Merge trunk. Don't use ListObjLength() in tclStrToD.c

Split tclEmptyStringRep declaration over two lines. Otherwise gcc warning.
Merge trunk. Just keep some shortcuts, no longer guarantee that SetListFromAny() really returns a list type. Still experimental.
2017-02-03 14:53:27 +00:00 · 2017-02-03 14:29:50 +00:00 · 2017-02-03 14:28:17 +00:00 · 2017-02-03 12:27:37 +00:00 · 2017-02-03 11:47:02 +00:00 · 2017-02-02 15:50:49 +00:00
674 changed files with 40723 additions and 44065 deletions
@@ -1,17 +0,0 @@
-compat/zlib/contrib/dotzlib/DotZLib/UnitTests.cs
-compat/zlib/contrib/vstudio/readme.txt
-compat/zlib/contrib/vstudio/*/zlib.rc
-compat/zlib/win32/*.txt
-compat/zlib/win64/*.txt
-libtommath/*.dsp
-libtommath/*.sln
-libtommath/*.vcproj
-tools/tcl.hpj.in
-tools/tcl.wse.in
-win/buildall.vc.bat
-win/coffbase.txt
-win/makefile.vc
-win/rules.vc
-win/tcl.dsp
-win/tcl.dsw
-win/tcl.hpj.in
@@ -3,13 +3,11 @@ compat/zlib/contrib/vstudio/readme.txt
 compat/zlib/contrib/vstudio/*/zlib.rc
 compat/zlib/win32/*.txt
 compat/zlib/win64/*.txt
-libtommath/*.dsp
-libtommath/*.sln
-libtommath/*.vcproj
 tools/tcl.hpj.in
 tools/tcl.wse.in
 win/buildall.vc.bat
 win/coffbase.txt
+win/makefile.bc
 win/makefile.vc
 win/rules.vc
 win/tcl.dsp
@@ -2,6 +2,7 @@ tools/tcl.hpj.in
 tools/tcl.wse.in
 win/buildall.vc.bat
 win/coffbase.txt
+win/makefile.bc
 win/makefile.vc
 win/rules.vc
 win/tcl.dsp
@@ -18,7 +18,6 @@
 */tclsh*
 */tcltest*
 */versions.vc
-*/version.vc
 html
 libtommath/bn.ilg
 libtommath/bn.ind
@@ -41,8 +40,7 @@ unix/dltest.marker
 unix/tcl.pc
 unix/tclIndex
 unix/pkgs/*
-win/Debug*
-win/Release*
+win/Debug_VC*
+win/Release_VC*
 win/pkgs/*
-win/tcl.hpj
-win/nmhlp-out.txt
+win/tcl.hpj
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <projectDescription>
-	<name>tcl8.6</name>
+	<name>tcl8.7</name>
 	<comment></comment>
 	<projects>
 	</projects>
@@ -1,5 +1,5 @@
 README:  Tcl
-    This is the Tcl 8.6.7 source distribution.
+    This is the Tcl 8.7a0 source distribution.
 	http://sourceforge.net/projects/tcl/files/Tcl/
    You can get any source release of Tcl from the URL above.

@@ -49,7 +49,7 @@ and selling it either in whole or in part.  See the file

 Extensive documentation is available at our website.
 The home page for this release, including new features, is
-	http://www.tcl.tk/software/tcltk/8.6.html
+	http://www.tcl.tk/software/tcltk/8.7.html

 Detailed release notes can be found at the file distributions page
 by clicking on the relevant version.
@@ -61,9 +61,9 @@ Information about Tcl itself can be found at
 There have been many Tcl books on the market.  Many are mentioned in the Wiki:
 	http://wiki.tcl.tk/_/ref?N=25206

-To view the complete set of reference manual entries for Tcl 8.6 online,
+To view the complete set of reference manual entries for Tcl 8.7 online,
 visit the URL:
-	http://www.tcl.tk/man/tcl8.6/
+	http://www.tcl.tk/man/tcl8.7/

 2a. Unix Documentation
 ----------------------
@@ -8624,177 +8624,3 @@ improvements to regexp engine from Postgres (lane,porter,fellows,seltenreich)
 2016-02-22 (bug)[9b4702] [info exists env(missing)] kills trace (nijtmans)

 --- Released 8.6.5, February 29, 2016 --- http://core.tcl.tk/tcl/ for details
-
-2016-03-01 (bug)[803042] mem leak due to reference cycle (porter)
-
-2016-03-08 (bug)[bbc304] reflected watch race condition (porter)
-
-2016-03-17 (bug)[fadc99] compile-5.3 (rodriguez,porter)
-
-2016-03-17 (enhancement)[1a25fd] compile [variable ${ns}::v] (porter)
-
-2016-03-20 (bug)[1af8de] crash in compiled [string replace] (harder,fellows)
-
-2016-03-21 (bug)[d30718] segv in notifier finalize (hirofumi,nijtmans)
-
-2016-03-23 (enhancement)[7d0db7] parallel make (yarda,nijtmans)
-
-2016-03-23 [f12535] enable test bindings customization (vogel,nijtmans)
-
-2016-04-04 (bug)[47ac84] compiled [lreplace] fixes (aspect,ferrieux,fellows)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-04-08 (bug)[866368] RE \w includes 'Punctuation Connector' (nijtmans)
-
-2016-04-08 (bug)[2538f3] Win crash Tcl_OpenTcpServer() (griffin)
-
-2016-04-10 [07d13d] Restore TclBlend support lost in 8.6.1 (buratti)
-
-2016-05-13 (bug)[3154ea] Mem corruption in assembler exceptions (tkob,kenny)
-
-2016-05-13 (bug) registry package support any Unicode env (nijtmans)
-=> registry 1.3.2
-
-2016-05-21 (bug)[f7d4e] [namespace delete] performance (fellows)
-
-2016-06-02 (TIP 447) execution time verbosity option (cerutti)
-=> tcltest 2.4.0
-
-2016-06-16 (bug)[16828b] crash due to [vwait] trace undo fail (dah,porter)
-
-2016-06-16 (enhancement)[4b61af] good [info frame] from more cases (beric)
-
-2016-06-21 (bug)[c383eb] crash in [glob -path a] (oehlmann,porter)
-
-2016-06-21 (update) Update Unicode data to 9.0 (nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-06-22 (bug)[16896d] Tcl_DString tolerate append to self. (dah,porter)
-
-2016-06-23 (bug)[d55322] crash in [dict update] (yorick,fellows)
-
-2016-06-27 (bug)[dd260a] crash in [chan configure -dictionary] (madden,aspect)
-
-2016-07-02 (bug)[f961d7] usage message with parameters with spaces (porter)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-07-02 (enhancement)[09fabc] Sort order of -relateddir (lanam)
-
-2016-07-07 (bug)[5d7ca0] Win: [file executable] for .cmd and .ps1 (nadkarni)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-07-08 (bug)[a47641] [file normalize] & Windows junctions (nadkarni)
-
-2016-07-09 [ae61a6] [file] handling of Win hardcoded names (CON) (nadkarni)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-07-09 [3613671] [file owned] (more) useful on Win (nadkarni)
-
-2016-07-09 (bug)[1493a4] [namespace upvar] use of resolvers (beric,fellows)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-07-10 (bug)[da340d] integer division in clock math (nadkarni)
-
-2016-07-20 tzdata updated to Olson's tzdata2016f (venkat)
-
--- Released 8.6.6, July 27, 2016 --- http://core.tcl.tk/tcl/ for details
-
-2016-09-07 (bug)[c09edf] Bad caching with  custom resolver (neumann,nijtmans)
-
-2016-09-07 (bug)[4dbdd9] Memleak in test var-8.3 (mr_calvin,porter)
-
-2016-10-03 (bug)[2bf561] Allow empty command as alias target (yorick,nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-10-04 (bug)[4d5ae7] Crash in async connects host no address (gahr,fellows)
-
-2016-10-08 (bug)[838e99] treat application/xml as text (gahr,fellows)
-=> http 2.8.10
-
-2016-10-11 (bug)[3cc1d9] Thread finalization crash in zippy (neumann)
-
-2016-10-12 (bug)[be003d] Fix [scan 0x1 %b], [scan 0x1 %o] (porter)
-
-2016-10-14 (bug)[eb6b68] Fix stringComp-14.5 (porter)
-
-2016-10-30 (bug)[b26e38] Fix zlib-7.8 (fellows)
-
-2016-10-30 (bug)[1ae129] Fix memleak in [history] destruction (fellows)
-
-2016-11-04 (feature) Provisional Tcl 9 support in msgcat and tcltest (nijtmans)
-=> msgcat 1.6.1
-=> tcltest 2.4.1
-
-2016-11-04 (bug)[824752] Crash in Tcl_ListObjReplace() (gahr,porter)
-
-2016-11-11 (bug)[79614f] invalidate VFS mounts on sytem encoding change (yorick)
-
-2016-11-14 OSX: End panic() as legacy support macro; system conflicts (nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2016-11-15 (bug) TclOO fix stops crash mixing Itcl and snit (fellows)
-
-2016-11-17 (update) Reconcile libtommath updates; purge unused files (nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2017-01-09 (bug)[b87ad7] Repair drifts in timer clock (sebres)
-
-2017-01-17 (update) => zlib 1.2.11 (nijtmans)
-
-2017-01-31 (bug)[39f630] Revise Tcl_LinkVar to tolerate some prefixes (nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2017-02-01 (bug)[d0f7ba] Improper NAN optimization. expr-22.1[01] (aspect)
-
-2017-02-26 (bug)[25842c] zlib stream finalization (aspect)
-
-2017-03-07 (deprecate) Remove unmaintained makefile.bc file (nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2017-03-14 (enhancement) [clock] and [encoding] are now ensembles (kenny)
-
-2017-03-15 (enhancement) several [clock] subcommands bytecoded (kenny)
-
-2017-03-23 tzdata updated to Olson's tzdata2017b (jima)
-
-2017-03-29 (bug)[900cb0] Fix OO unexport introspection (napier)
-
-2017-04-12 (bug)[42202b] Nesting imbalance in coro injection (nadkarni,sebres)
-
-2017-04-18 (bug)[bc4322] http package support for safe interps (nash,nijtmans)
-
-2017-04-28 (bug)[f34cf8] [file join a //b] => /b (neumann,porter)
-
-2017-05-01 (bug)[8bd13f] Windows threads and pipes (sebres,nijtmans)
-
-2017-05-01 (bug)[f9fe90] [file join //a b] EIAS violation (aspect,porter)
-
-2017-05-04 (bug) Make test filesystem-1.52 pass on Windows (nijtmans)
-
-2017-05-05 (bug)[601522] [binary] field spec overflow -> segfault (porter)
-
-2017-05-08 (bug)[6ca52a] http memleak handling keep-alive (aspect,nijtmans)
-=> http 2.8.11
-
-2017-05-29 (bug)[a3fb33] crash in [lsort] on long lists (sebres)
-
-2017-06-05 (bug)[67aa9a] Tcl_UtfToUniChar() revised handling invalid UTF-8 (nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2017-06-08 (bug)[2738427] Tcl_NumUtfChars() corner case utf-4.9 (nijtmans)
-
-2017-06-22 (update) Update Unicode data to 10.0 (nijtmans)
-        *** POTENTIAL INCOMPATIBILITY ***
-
-2017-06-22 (TIP 473) Let [oo::copy] specify target namespace (fellows)
-
-2017-06-26 (bug)[46f801] Repair autoloader fragility (porter)
-
-2017-07-06 (bug)[adb198] Plug memleak in TclJoinPath (sebres,porter)
-
-2017-07-17 (bug)[fb2208] Repeatable tclIndex generation (wiedemann,nijtmans)
-
--- Released 8.6.7, August 9, 2017 --- http://core.tcl.tk/tcl/ for details
-
-2017-08-31 (bug)[2a9465] http state 100 continue handling broken (oehlmann)
-=> http 2.8.12
@@ -106,5 +106,5 @@ closedir(
    close(dirp->dd_fd);
    dirp->dd_fd = -1;
    dirp->dd_loc = 0;
-    ckfree((char *) dirp);
+    ckfree(dirp);
 }
@@ -100,7 +100,7 @@ waitpid(
 	} else {
 	    prevPtr->nextPtr = waitPtr->nextPtr;
 	}
-	ckfree((char *) waitPtr);
+	ckfree(waitPtr);
 	return result;
    }

@@ -0,0 +1,209 @@
+1. Compression algorithm (deflate)
+
+The deflation algorithm used by gzip (also zip and zlib) is a variation of
+LZ77 (Lempel-Ziv 1977, see reference below). It finds duplicated strings in
+the input data.  The second occurrence of a string is replaced by a
+pointer to the previous string, in the form of a pair (distance,
+length).  Distances are limited to 32K bytes, and lengths are limited
+to 258 bytes. When a string does not occur anywhere in the previous
+32K bytes, it is emitted as a sequence of literal bytes.  (In this
+description, `string' must be taken as an arbitrary sequence of bytes,
+and is not restricted to printable characters.)
+
+Literals or match lengths are compressed with one Huffman tree, and
+match distances are compressed with another tree. The trees are stored
+in a compact form at the start of each block. The blocks can have any
+size (except that the compressed data for one block must fit in
+available memory). A block is terminated when deflate() determines that
+it would be useful to start another block with fresh trees. (This is
+somewhat similar to the behavior of LZW-based _compress_.)
+
+Duplicated strings are found using a hash table. All input strings of
+length 3 are inserted in the hash table. A hash index is computed for
+the next 3 bytes. If the hash chain for this index is not empty, all
+strings in the chain are compared with the current input string, and
+the longest match is selected.
+
+The hash chains are searched starting with the most recent strings, to
+favor small distances and thus take advantage of the Huffman encoding.
+The hash chains are singly linked. There are no deletions from the
+hash chains, the algorithm simply discards matches that are too old.
+
+To avoid a worst-case situation, very long hash chains are arbitrarily
+truncated at a certain length, determined by a runtime option (level
+parameter of deflateInit). So deflate() does not always find the longest
+possible match but generally finds a match which is long enough.
+
+deflate() also defers the selection of matches with a lazy evaluation
+mechanism. After a match of length N has been found, deflate() searches for
+a longer match at the next input byte. If a longer match is found, the
+previous match is truncated to a length of one (thus producing a single
+literal byte) and the process of lazy evaluation begins again. Otherwise,
+the original match is kept, and the next match search is attempted only N
+steps later.
+
+The lazy match evaluation is also subject to a runtime parameter. If
+the current match is long enough, deflate() reduces the search for a longer
+match, thus speeding up the whole process. If compression ratio is more
+important than speed, deflate() attempts a complete second search even if
+the first match is already long enough.
+
+The lazy match evaluation is not performed for the fastest compression
+modes (level parameter 1 to 3). For these fast modes, new strings
+are inserted in the hash table only when no match was found, or
+when the match is not too long. This degrades the compression ratio
+but saves time since there are both fewer insertions and fewer searches.
+
+
+2. Decompression algorithm (inflate)
+
+2.1 Introduction
+
+The key question is how to represent a Huffman code (or any prefix code) so
+that you can decode fast.  The most important characteristic is that shorter
+codes are much more common than longer codes, so pay attention to decoding the
+short codes fast, and let the long codes take longer to decode.
+
+inflate() sets up a first level table that covers some number of bits of
+input less than the length of longest code.  It gets that many bits from the
+stream, and looks it up in the table.  The table will tell if the next
+code is that many bits or less and how many, and if it is, it will tell
+the value, else it will point to the next level table for which inflate()
+grabs more bits and tries to decode a longer code.
+
+How many bits to make the first lookup is a tradeoff between the time it
+takes to decode and the time it takes to build the table.  If building the
+table took no time (and if you had infinite memory), then there would only
+be a first level table to cover all the way to the longest code.  However,
+building the table ends up taking a lot longer for more bits since short
+codes are replicated many times in such a table.  What inflate() does is
+simply to make the number of bits in the first table a variable, and  then
+to set that variable for the maximum speed.
+
+For inflate, which has 286 possible codes for the literal/length tree, the size
+of the first table is nine bits.  Also the distance trees have 30 possible
+values, and the size of the first table is six bits.  Note that for each of
+those cases, the table ended up one bit longer than the ``average'' code
+length, i.e. the code length of an approximately flat code which would be a
+little more than eight bits for 286 symbols and a little less than five bits
+for 30 symbols.
+
+
+2.2 More details on the inflate table lookup
+
+Ok, you want to know what this cleverly obfuscated inflate tree actually
+looks like.  You are correct that it's not a Huffman tree.  It is simply a
+lookup table for the first, let's say, nine bits of a Huffman symbol.  The
+symbol could be as short as one bit or as long as 15 bits.  If a particular
+symbol is shorter than nine bits, then that symbol's translation is duplicated
+in all those entries that start with that symbol's bits.  For example, if the
+symbol is four bits, then it's duplicated 32 times in a nine-bit table.  If a
+symbol is nine bits long, it appears in the table once.
+
+If the symbol is longer than nine bits, then that entry in the table points
+to another similar table for the remaining bits.  Again, there are duplicated
+entries as needed.  The idea is that most of the time the symbol will be short
+and there will only be one table look up.  (That's whole idea behind data
+compression in the first place.)  For the less frequent long symbols, there
+will be two lookups.  If you had a compression method with really long
+symbols, you could have as many levels of lookups as is efficient.  For
+inflate, two is enough.
+
+So a table entry either points to another table (in which case nine bits in
+the above example are gobbled), or it contains the translation for the symbol
+and the number of bits to gobble.  Then you start again with the next
+ungobbled bit.
+
+You may wonder: why not just have one lookup table for how ever many bits the
+longest symbol is?  The reason is that if you do that, you end up spending
+more time filling in duplicate symbol entries than you do actually decoding.
+At least for deflate's output that generates new trees every several 10's of
+kbytes.  You can imagine that filling in a 2^15 entry table for a 15-bit code
+would take too long if you're only decoding several thousand symbols.  At the
+other extreme, you could make a new table for every bit in the code.  In fact,
+that's essentially a Huffman tree.  But then you spend too much time
+traversing the tree while decoding, even for short symbols.
+
+So the number of bits for the first lookup table is a trade of the time to
+fill out the table vs. the time spent looking at the second level and above of
+the table.
+
+Here is an example, scaled down:
+
+The code being decoded, with 10 symbols, from 1 to 6 bits long:
+
+A: 0
+B: 10
+C: 1100
+D: 11010
+E: 11011
+F: 11100
+G: 11101
+H: 11110
+I: 111110
+J: 111111
+
+Let's make the first table three bits long (eight entries):
+
+000: A,1
+001: A,1
+010: A,1
+011: A,1
+100: B,2
+101: B,2
+110: -> table X (gobble 3 bits)
+111: -> table Y (gobble 3 bits)
+
+Each entry is what the bits decode as and how many bits that is, i.e. how
+many bits to gobble.  Or the entry points to another table, with the number of
+bits to gobble implicit in the size of the table.
+
+Table X is two bits long since the longest code starting with 110 is five bits
+long:
+
+00: C,1
+01: C,1
+10: D,2
+11: E,2
+
+Table Y is three bits long since the longest code starting with 111 is six
+bits long:
+
+000: F,2
+001: F,2
+010: G,2
+011: G,2
+100: H,2
+101: H,2
+110: I,3
+111: J,3
+
+So what we have here are three tables with a total of 20 entries that had to
+be constructed.  That's compared to 64 entries for a single table.  Or
+compared to 16 entries for a Huffman tree (six two entry tables and one four
+entry table).  Assuming that the code ideally represents the probability of
+the symbols, it takes on the average 1.25 lookups per symbol.  That's compared
+to one lookup for the single table, or 1.66 lookups per symbol for the
+Huffman tree.
+
+There, I think that gives you a picture of what's going on.  For inflate, the
+meaning of a particular symbol is often more than just a letter.  It can be a
+byte (a "literal"), or it can be either a length or a distance which
+indicates a base value and a number of bits to fetch after the code that is
+added to the base value.  Or it might be the special end-of-block code.  The
+data structures created in inftrees.c try to encode all that information
+compactly in the tables.
+
+
+Jean-loup Gailly        Mark Adler
+jloup@gzip.org          madler@alumni.caltech.edu
+
+
+References:
+
+[LZ77] Ziv J., Lempel A., ``A Universal Algorithm for Sequential Data
+Compression,'' IEEE Transactions on Information Theory, Vol. 23, No. 3,
+pp. 337-343.
+
+``DEFLATE Compressed Data Format Specification'' available in
+http://tools.ietf.org/html/rfc1951
@@ -0,0 +1,619 @@
+
+
+
+
+
+
+Network Working Group                                         P. Deutsch
+Request for Comments: 1950                           Aladdin Enterprises
+Category: Informational                                      J-L. Gailly
+                                                                Info-ZIP
+                                                                May 1996
+
+
+         ZLIB Compressed Data Format Specification version 3.3
+
+Status of This Memo
+
+   This memo provides information for the Internet community.  This memo
+   does not specify an Internet standard of any kind.  Distribution of
+   this memo is unlimited.
+
+IESG Note:
+
+   The IESG takes no position on the validity of any Intellectual
+   Property Rights statements contained in this document.
+
+Notices
+
+   Copyright (c) 1996 L. Peter Deutsch and Jean-Loup Gailly
+
+   Permission is granted to copy and distribute this document for any
+   purpose and without charge, including translations into other
+   languages and incorporation into compilations, provided that the
+   copyright notice and this notice are preserved, and that any
+   substantive changes or deletions from the original are clearly
+   marked.
+
+   A pointer to the latest version of this and related documentation in
+   HTML format can be found at the URL
+   <ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html>.
+
+Abstract
+
+   This specification defines a lossless compressed data format.  The
+   data can be produced or consumed, even for an arbitrarily long
+   sequentially presented input data stream, using only an a priori
+   bounded amount of intermediate storage.  The format presently uses
+   the DEFLATE compression method but can be easily extended to use
+   other compression methods.  It can be implemented readily in a manner
+   not covered by patents.  This specification also defines the ADLER-32
+   checksum (an extension and improvement of the Fletcher checksum),
+   used for detection of data corruption, and provides an algorithm for
+   computing it.
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 1]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+Table of Contents
+
+   1. Introduction ................................................... 2
+      1.1. Purpose ................................................... 2
+      1.2. Intended audience ......................................... 3
+      1.3. Scope ..................................................... 3
+      1.4. Compliance ................................................ 3
+      1.5.  Definitions of terms and conventions used ................ 3
+      1.6. Changes from previous versions ............................ 3
+   2. Detailed specification ......................................... 3
+      2.1. Overall conventions ....................................... 3
+      2.2. Data format ............................................... 4
+      2.3. Compliance ................................................ 7
+   3. References ..................................................... 7
+   4. Source code .................................................... 8
+   5. Security Considerations ........................................ 8
+   6. Acknowledgements ............................................... 8
+   7. Authors' Addresses ............................................. 8
+   8. Appendix: Rationale ............................................ 9
+   9. Appendix: Sample code ..........................................10
+
+1. Introduction
+
+   1.1. Purpose
+
+      The purpose of this specification is to define a lossless
+      compressed data format that:
+
+          * Is independent of CPU type, operating system, file system,
+            and character set, and hence can be used for interchange;
+
+          * Can be produced or consumed, even for an arbitrarily long
+            sequentially presented input data stream, using only an a
+            priori bounded amount of intermediate storage, and hence can
+            be used in data communications or similar structures such as
+            Unix filters;
+
+          * Can use a number of different compression methods;
+
+          * Can be implemented readily in a manner not covered by
+            patents, and hence can be practiced freely.
+
+      The data format defined by this specification does not attempt to
+      allow random access to compressed data.
+
+
+
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 2]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+   1.2. Intended audience
+
+      This specification is intended for use by implementors of software
+      to compress data into zlib format and/or decompress data from zlib
+      format.
+
+      The text of the specification assumes a basic background in
+      programming at the level of bits and other primitive data
+      representations.
+
+   1.3. Scope
+
+      The specification specifies a compressed data format that can be
+      used for in-memory compression of a sequence of arbitrary bytes.
+
+   1.4. Compliance
+
+      Unless otherwise indicated below, a compliant decompressor must be
+      able to accept and decompress any data set that conforms to all
+      the specifications presented here; a compliant compressor must
+      produce data sets that conform to all the specifications presented
+      here.
+
+   1.5.  Definitions of terms and conventions used
+
+      byte: 8 bits stored or transmitted as a unit (same as an octet).
+      (For this specification, a byte is exactly 8 bits, even on
+      machines which store a character on a number of bits different
+      from 8.) See below, for the numbering of bits within a byte.
+
+   1.6. Changes from previous versions
+
+      Version 3.1 was the first public release of this specification.
+      In version 3.2, some terminology was changed and the Adler-32
+      sample code was rewritten for clarity.  In version 3.3, the
+      support for a preset dictionary was introduced, and the
+      specification was converted to RFC style.
+
+2. Detailed specification
+
+   2.1. Overall conventions
+
+      In the diagrams below, a box like this:
+
+         +---+
+         |   | <-- the vertical bars might be missing
+         +---+
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 3]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+      represents one byte; a box like this:
+
+         +==============+
+         |              |
+         +==============+
+
+      represents a variable number of bytes.
+
+      Bytes stored within a computer do not have a "bit order", since
+      they are always treated as a unit.  However, a byte considered as
+      an integer between 0 and 255 does have a most- and least-
+      significant bit, and since we write numbers with the most-
+      significant digit on the left, we also write bytes with the most-
+      significant bit on the left.  In the diagrams below, we number the
+      bits of a byte so that bit 0 is the least-significant bit, i.e.,
+      the bits are numbered:
+
+         +--------+
+         |76543210|
+         +--------+
+
+      Within a computer, a number may occupy multiple bytes.  All
+      multi-byte numbers in the format described here are stored with
+      the MOST-significant byte first (at the lower memory address).
+      For example, the decimal number 520 is stored as:
+
+             0     1
+         +--------+--------+
+         |00000010|00001000|
+         +--------+--------+
+          ^        ^
+          |        |
+          |        + less significant byte = 8
+          + more significant byte = 2 x 256
+
+   2.2. Data format
+
+      A zlib stream has the following structure:
+
+           0   1
+         +---+---+
+         |CMF|FLG|   (more-->)
+         +---+---+
+
+
+
+
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 4]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+      (if FLG.FDICT set)
+
+           0   1   2   3
+         +---+---+---+---+
+         |     DICTID    |   (more-->)
+         +---+---+---+---+
+
+         +=====================+---+---+---+---+
+         |...compressed data...|    ADLER32    |
+         +=====================+---+---+---+---+
+
+      Any data which may appear after ADLER32 are not part of the zlib
+      stream.
+
+      CMF (Compression Method and flags)
+         This byte is divided into a 4-bit compression method and a 4-
+         bit information field depending on the compression method.
+
+            bits 0 to 3  CM     Compression method
+            bits 4 to 7  CINFO  Compression info
+
+      CM (Compression method)
+         This identifies the compression method used in the file. CM = 8
+         denotes the "deflate" compression method with a window size up
+         to 32K.  This is the method used by gzip and PNG (see
+         references [1] and [2] in Chapter 3, below, for the reference
+         documents).  CM = 15 is reserved.  It might be used in a future
+         version of this specification to indicate the presence of an
+         extra field before the compressed data.
+
+      CINFO (Compression info)
+         For CM = 8, CINFO is the base-2 logarithm of the LZ77 window
+         size, minus eight (CINFO=7 indicates a 32K window size). Values
+         of CINFO above 7 are not allowed in this version of the
+         specification.  CINFO is not defined in this specification for
+         CM not equal to 8.
+
+      FLG (FLaGs)
+         This flag byte is divided as follows:
+
+            bits 0 to 4  FCHECK  (check bits for CMF and FLG)
+            bit  5       FDICT   (preset dictionary)
+            bits 6 to 7  FLEVEL  (compression level)
+
+         The FCHECK value must be such that CMF and FLG, when viewed as
+         a 16-bit unsigned integer stored in MSB order (CMF*256 + FLG),
+         is a multiple of 31.
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 5]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+      FDICT (Preset dictionary)
+         If FDICT is set, a DICT dictionary identifier is present
+         immediately after the FLG byte. The dictionary is a sequence of
+         bytes which are initially fed to the compressor without
+         producing any compressed output. DICT is the Adler-32 checksum
+         of this sequence of bytes (see the definition of ADLER32
+         below).  The decompressor can use this identifier to determine
+         which dictionary has been used by the compressor.
+
+      FLEVEL (Compression level)
+         These flags are available for use by specific compression
+         methods.  The "deflate" method (CM = 8) sets these flags as
+         follows:
+
+            0 - compressor used fastest algorithm
+            1 - compressor used fast algorithm
+            2 - compressor used default algorithm
+            3 - compressor used maximum compression, slowest algorithm
+
+         The information in FLEVEL is not needed for decompression; it
+         is there to indicate if recompression might be worthwhile.
+
+      compressed data
+         For compression method 8, the compressed data is stored in the
+         deflate compressed data format as described in the document
+         "DEFLATE Compressed Data Format Specification" by L. Peter
+         Deutsch. (See reference [3] in Chapter 3, below)
+
+         Other compressed data formats are not specified in this version
+         of the zlib specification.
+
+      ADLER32 (Adler-32 checksum)
+         This contains a checksum value of the uncompressed data
+         (excluding any dictionary data) computed according to Adler-32
+         algorithm. This algorithm is a 32-bit extension and improvement
+         of the Fletcher algorithm, used in the ITU-T X.224 / ISO 8073
+         standard. See references [4] and [5] in Chapter 3, below)
+
+         Adler-32 is composed of two sums accumulated per byte: s1 is
+         the sum of all bytes, s2 is the sum of all s1 values. Both sums
+         are done modulo 65521. s1 is initialized to 1, s2 to zero.  The
+         Adler-32 checksum is stored as s2*65536 + s1 in most-
+         significant-byte first (network) order.
+
+
+
+
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 6]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+   2.3. Compliance
+
+      A compliant compressor must produce streams with correct CMF, FLG
+      and ADLER32, but need not support preset dictionaries.  When the
+      zlib data format is used as part of another standard data format,
+      the compressor may use only preset dictionaries that are specified
+      by this other data format.  If this other format does not use the
+      preset dictionary feature, the compressor must not set the FDICT
+      flag.
+
+      A compliant decompressor must check CMF, FLG, and ADLER32, and
+      provide an error indication if any of these have incorrect values.
+      A compliant decompressor must give an error indication if CM is
+      not one of the values defined in this specification (only the
+      value 8 is permitted in this version), since another value could
+      indicate the presence of new features that would cause subsequent
+      data to be interpreted incorrectly.  A compliant decompressor must
+      give an error indication if FDICT is set and DICTID is not the
+      identifier of a known preset dictionary.  A decompressor may
+      ignore FLEVEL and still be compliant.  When the zlib data format
+      is being used as a part of another standard format, a compliant
+      decompressor must support all the preset dictionaries specified by
+      the other format. When the other format does not use the preset
+      dictionary feature, a compliant decompressor must reject any
+      stream in which the FDICT flag is set.
+
+3. References
+
+   [1] Deutsch, L.P.,"GZIP Compressed Data Format Specification",
+       available in ftp://ftp.uu.net/pub/archiving/zip/doc/
+
+   [2] Thomas Boutell, "PNG (Portable Network Graphics) specification",
+       available in ftp://ftp.uu.net/graphics/png/documents/
+
+   [3] Deutsch, L.P.,"DEFLATE Compressed Data Format Specification",
+       available in ftp://ftp.uu.net/pub/archiving/zip/doc/
+
+   [4] Fletcher, J. G., "An Arithmetic Checksum for Serial
+       Transmissions," IEEE Transactions on Communications, Vol. COM-30,
+       No. 1, January 1982, pp. 247-252.
+
+   [5] ITU-T Recommendation X.224, Annex D, "Checksum Algorithms,"
+       November, 1993, pp. 144, 145. (Available from
+       gopher://info.itu.ch). ITU-T X.244 is also the same as ISO 8073.
+
+
+
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 7]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+4. Source code
+
+   Source code for a C language implementation of a "zlib" compliant
+   library is available at ftp://ftp.uu.net/pub/archiving/zip/zlib/.
+
+5. Security Considerations
+
+   A decoder that fails to check the ADLER32 checksum value may be
+   subject to undetected data corruption.
+
+6. Acknowledgements
+
+   Trademarks cited in this document are the property of their
+   respective owners.
+
+   Jean-Loup Gailly and Mark Adler designed the zlib format and wrote
+   the related software described in this specification.  Glenn
+   Randers-Pehrson converted this document to RFC and HTML format.
+
+7. Authors' Addresses
+
+   L. Peter Deutsch
+   Aladdin Enterprises
+   203 Santa Margarita Ave.
+   Menlo Park, CA 94025
+
+   Phone: (415) 322-0103 (AM only)
+   FAX:   (415) 322-1734
+   EMail: <ghost@aladdin.com>
+
+
+   Jean-Loup Gailly
+
+   EMail: <gzip@prep.ai.mit.edu>
+
+   Questions about the technical content of this specification can be
+   sent by email to
+
+   Jean-Loup Gailly <gzip@prep.ai.mit.edu> and
+   Mark Adler <madler@alumni.caltech.edu>
+
+   Editorial comments on this specification can be sent by email to
+
+   L. Peter Deutsch <ghost@aladdin.com> and
+   Glenn Randers-Pehrson <randeg@alumni.rpi.edu>
+
+
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 8]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+8. Appendix: Rationale
+
+   8.1. Preset dictionaries
+
+      A preset dictionary is specially useful to compress short input
+      sequences. The compressor can take advantage of the dictionary
+      context to encode the input in a more compact manner. The
+      decompressor can be initialized with the appropriate context by
+      virtually decompressing a compressed version of the dictionary
+      without producing any output. However for certain compression
+      algorithms such as the deflate algorithm this operation can be
+      achieved without actually performing any decompression.
+
+      The compressor and the decompressor must use exactly the same
+      dictionary. The dictionary may be fixed or may be chosen among a
+      certain number of predefined dictionaries, according to the kind
+      of input data. The decompressor can determine which dictionary has
+      been chosen by the compressor by checking the dictionary
+      identifier. This document does not specify the contents of
+      predefined dictionaries, since the optimal dictionaries are
+      application specific. Standard data formats using this feature of
+      the zlib specification must precisely define the allowed
+      dictionaries.
+
+   8.2. The Adler-32 algorithm
+
+      The Adler-32 algorithm is much faster than the CRC32 algorithm yet
+      still provides an extremely low probability of undetected errors.
+
+      The modulo on unsigned long accumulators can be delayed for 5552
+      bytes, so the modulo operation time is negligible.  If the bytes
+      are a, b, c, the second sum is 3a + 2b + c + 3, and so is position
+      and order sensitive, unlike the first sum, which is just a
+      checksum.  That 65521 is prime is important to avoid a possible
+      large class of two-byte errors that leave the check unchanged.
+      (The Fletcher checksum uses 255, which is not prime and which also
+      makes the Fletcher check insensitive to single byte changes 0 <->
+      255.)
+
+      The sum s1 is initialized to 1 instead of zero to make the length
+      of the sequence part of s2, so that the length does not have to be
+      checked separately. (Any sequence of zeroes has a Fletcher
+      checksum of zero.)
+
+
+
+
+
+
+
+
+Deutsch & Gailly             Informational                      [Page 9]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+9. Appendix: Sample code
+
+   The following C code computes the Adler-32 checksum of a data buffer.
+   It is written for clarity, not for speed.  The sample code is in the
+   ANSI C programming language. Non C users may find it easier to read
+   with these hints:
+
+      &      Bitwise AND operator.
+      >>     Bitwise right shift operator. When applied to an
+             unsigned quantity, as here, right shift inserts zero bit(s)
+             at the left.
+      <<     Bitwise left shift operator. Left shift inserts zero
+             bit(s) at the right.
+      ++     "n++" increments the variable n.
+      %      modulo operator: a % b is the remainder of a divided by b.
+
+      #define BASE 65521 /* largest prime smaller than 65536 */
+
+      /*
+         Update a running Adler-32 checksum with the bytes buf[0..len-1]
+       and return the updated checksum. The Adler-32 checksum should be
+       initialized to 1.
+
+       Usage example:
+
+         unsigned long adler = 1L;
+
+         while (read_buffer(buffer, length) != EOF) {
+           adler = update_adler32(adler, buffer, length);
+         }
+         if (adler != original_adler) error();
+      */
+      unsigned long update_adler32(unsigned long adler,
+         unsigned char *buf, int len)
+      {
+        unsigned long s1 = adler & 0xffff;
+        unsigned long s2 = (adler >> 16) & 0xffff;
+        int n;
+
+        for (n = 0; n < len; n++) {
+          s1 = (s1 + buf[n]) % BASE;
+          s2 = (s2 + s1)     % BASE;
+        }
+        return (s2 << 16) + s1;
+      }
+
+      /* Return the adler32 of the bytes buf[0..len-1] */
+
+
+
+
+Deutsch & Gailly             Informational                     [Page 10]
+
+RFC 1950       ZLIB Compressed Data Format Specification        May 1996
+
+
+      unsigned long adler32(unsigned char *buf, int len)
+      {
+        return update_adler32(1L, buf, len);
+      }
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
+
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+Deutsch & Gailly             Informational                     [Page 11]
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+
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+
+
+
+Network Working Group                                         P. Deutsch
+Request for Comments: 1951                           Aladdin Enterprises
+Category: Informational                                         May 1996
+
+
+        DEFLATE Compressed Data Format Specification version 1.3
+
+Status of This Memo
+
+   This memo provides information for the Internet community.  This memo
+   does not specify an Internet standard of any kind.  Distribution of
+   this memo is unlimited.
+
+IESG Note:
+
+   The IESG takes no position on the validity of any Intellectual
+   Property Rights statements contained in this document.
+
+Notices
+
+   Copyright (c) 1996 L. Peter Deutsch
+
+   Permission is granted to copy and distribute this document for any
+   purpose and without charge, including translations into other
+   languages and incorporation into compilations, provided that the
+   copyright notice and this notice are preserved, and that any
+   substantive changes or deletions from the original are clearly
+   marked.
+
+   A pointer to the latest version of this and related documentation in
+   HTML format can be found at the URL
+   <ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html>.
+
+Abstract
+
+   This specification defines a lossless compressed data format that
+   compresses data using a combination of the LZ77 algorithm and Huffman
+   coding, with efficiency comparable to the best currently available
+   general-purpose compression methods.  The data can be produced or
+   consumed, even for an arbitrarily long sequentially presented input
+   data stream, using only an a priori bounded amount of intermediate
+   storage.  The format can be implemented readily in a manner not
+   covered by patents.
+
+
+
+
+
+
+
+
+Deutsch                      Informational                      [Page 1]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+Table of Contents
+
+   1. Introduction ................................................... 2
+      1.1. Purpose ................................................... 2
+      1.2. Intended audience ......................................... 3
+      1.3. Scope ..................................................... 3
+      1.4. Compliance ................................................ 3
+      1.5.  Definitions of terms and conventions used ................ 3
+      1.6. Changes from previous versions ............................ 4
+   2. Compressed representation overview ............................. 4
+   3. Detailed specification ......................................... 5
+      3.1. Overall conventions ....................................... 5
+          3.1.1. Packing into bytes .................................. 5
+      3.2. Compressed block format ................................... 6
+          3.2.1. Synopsis of prefix and Huffman coding ............... 6
+          3.2.2. Use of Huffman coding in the "deflate" format ....... 7
+          3.2.3. Details of block format ............................. 9
+          3.2.4. Non-compressed blocks (BTYPE=00) ................... 11
+          3.2.5. Compressed blocks (length and distance codes) ...... 11
+          3.2.6. Compression with fixed Huffman codes (BTYPE=01) .... 12
+          3.2.7. Compression with dynamic Huffman codes (BTYPE=10) .. 13
+      3.3. Compliance ............................................... 14
+   4. Compression algorithm details ................................. 14
+   5. References .................................................... 16
+   6. Security Considerations ....................................... 16
+   7. Source code ................................................... 16
+   8. Acknowledgements .............................................. 16
+   9. Author's Address .............................................. 17
+
+1. Introduction
+
+   1.1. Purpose
+
+      The purpose of this specification is to define a lossless
+      compressed data format that:
+          * Is independent of CPU type, operating system, file system,
+            and character set, and hence can be used for interchange;
+          * Can be produced or consumed, even for an arbitrarily long
+            sequentially presented input data stream, using only an a
+            priori bounded amount of intermediate storage, and hence
+            can be used in data communications or similar structures
+            such as Unix filters;
+          * Compresses data with efficiency comparable to the best
+            currently available general-purpose compression methods,
+            and in particular considerably better than the "compress"
+            program;
+          * Can be implemented readily in a manner not covered by
+            patents, and hence can be practiced freely;
+
+
+
+Deutsch                      Informational                      [Page 2]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+          * Is compatible with the file format produced by the current
+            widely used gzip utility, in that conforming decompressors
+            will be able to read data produced by the existing gzip
+            compressor.
+
+      The data format defined by this specification does not attempt to:
+
+          * Allow random access to compressed data;
+          * Compress specialized data (e.g., raster graphics) as well
+            as the best currently available specialized algorithms.
+
+      A simple counting argument shows that no lossless compression
+      algorithm can compress every possible input data set.  For the
+      format defined here, the worst case expansion is 5 bytes per 32K-
+      byte block, i.e., a size increase of 0.015% for large data sets.
+      English text usually compresses by a factor of 2.5 to 3;
+      executable files usually compress somewhat less; graphical data
+      such as raster images may compress much more.
+
+   1.2. Intended audience
+
+      This specification is intended for use by implementors of software
+      to compress data into "deflate" format and/or decompress data from
+      "deflate" format.
+
+      The text of the specification assumes a basic background in
+      programming at the level of bits and other primitive data
+      representations.  Familiarity with the technique of Huffman coding
+      is helpful but not required.
+
+   1.3. Scope
+
+      The specification specifies a method for representing a sequence
+      of bytes as a (usually shorter) sequence of bits, and a method for
+      packing the latter bit sequence into bytes.
+
+   1.4. Compliance
+
+      Unless otherwise indicated below, a compliant decompressor must be
+      able to accept and decompress any data set that conforms to all
+      the specifications presented here; a compliant compressor must
+      produce data sets that conform to all the specifications presented
+      here.
+
+   1.5.  Definitions of terms and conventions used
+
+      Byte: 8 bits stored or transmitted as a unit (same as an octet).
+      For this specification, a byte is exactly 8 bits, even on machines
+
+
+
+Deutsch                      Informational                      [Page 3]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+      which store a character on a number of bits different from eight.
+      See below, for the numbering of bits within a byte.
+
+      String: a sequence of arbitrary bytes.
+
+   1.6. Changes from previous versions
+
+      There have been no technical changes to the deflate format since
+      version 1.1 of this specification.  In version 1.2, some
+      terminology was changed.  Version 1.3 is a conversion of the
+      specification to RFC style.
+
+2. Compressed representation overview
+
+   A compressed data set consists of a series of blocks, corresponding
+   to successive blocks of input data.  The block sizes are arbitrary,
+   except that non-compressible blocks are limited to 65,535 bytes.
+
+   Each block is compressed using a combination of the LZ77 algorithm
+   and Huffman coding. The Huffman trees for each block are independent
+   of those for previous or subsequent blocks; the LZ77 algorithm may
+   use a reference to a duplicated string occurring in a previous block,
+   up to 32K input bytes before.
+
+   Each block consists of two parts: a pair of Huffman code trees that
+   describe the representation of the compressed data part, and a
+   compressed data part.  (The Huffman trees themselves are compressed
+   using Huffman encoding.)  The compressed data consists of a series of
+   elements of two types: literal bytes (of strings that have not been
+   detected as duplicated within the previous 32K input bytes), and
+   pointers to duplicated strings, where a pointer is represented as a
+   pair <length, backward distance>.  The representation used in the
+   "deflate" format limits distances to 32K bytes and lengths to 258
+   bytes, but does not limit the size of a block, except for
+   uncompressible blocks, which are limited as noted above.
+
+   Each type of value (literals, distances, and lengths) in the
+   compressed data is represented using a Huffman code, using one code
+   tree for literals and lengths and a separate code tree for distances.
+   The code trees for each block appear in a compact form just before
+   the compressed data for that block.
+
+
+
+
+
+
+
+
+
+
+Deutsch                      Informational                      [Page 4]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+3. Detailed specification
+
+   3.1. Overall conventions In the diagrams below, a box like this:
+
+         +---+
+         |   | <-- the vertical bars might be missing
+         +---+
+
+      represents one byte; a box like this:
+
+         +==============+
+         |              |
+         +==============+
+
+      represents a variable number of bytes.
+
+      Bytes stored within a computer do not have a "bit order", since
+      they are always treated as a unit.  However, a byte considered as
+      an integer between 0 and 255 does have a most- and least-
+      significant bit, and since we write numbers with the most-
+      significant digit on the left, we also write bytes with the most-
+      significant bit on the left.  In the diagrams below, we number the
+      bits of a byte so that bit 0 is the least-significant bit, i.e.,
+      the bits are numbered:
+
+         +--------+
+         |76543210|
+         +--------+
+
+      Within a computer, a number may occupy multiple bytes.  All
+      multi-byte numbers in the format described here are stored with
+      the least-significant byte first (at the lower memory address).
+      For example, the decimal number 520 is stored as:
+
+             0        1
+         +--------+--------+
+         |00001000|00000010|
+         +--------+--------+
+          ^        ^
+          |        |
+          |        + more significant byte = 2 x 256
+          + less significant byte = 8
+
+      3.1.1. Packing into bytes
+
+         This document does not address the issue of the order in which
+         bits of a byte are transmitted on a bit-sequential medium,
+         since the final data format described here is byte- rather than
+
+
+
+Deutsch                      Informational                      [Page 5]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+         bit-oriented.  However, we describe the compressed block format
+         in below, as a sequence of data elements of various bit
+         lengths, not a sequence of bytes.  We must therefore specify
+         how to pack these data elements into bytes to form the final
+         compressed byte sequence:
+
+             * Data elements are packed into bytes in order of
+               increasing bit number within the byte, i.e., starting
+               with the least-significant bit of the byte.
+             * Data elements other than Huffman codes are packed
+               starting with the least-significant bit of the data
+               element.
+             * Huffman codes are packed starting with the most-
+               significant bit of the code.
+
+         In other words, if one were to print out the compressed data as
+         a sequence of bytes, starting with the first byte at the
+         *right* margin and proceeding to the *left*, with the most-
+         significant bit of each byte on the left as usual, one would be
+         able to parse the result from right to left, with fixed-width
+         elements in the correct MSB-to-LSB order and Huffman codes in
+         bit-reversed order (i.e., with the first bit of the code in the
+         relative LSB position).
+
+   3.2. Compressed block format
+
+      3.2.1. Synopsis of prefix and Huffman coding
+
+         Prefix coding represents symbols from an a priori known
+         alphabet by bit sequences (codes), one code for each symbol, in
+         a manner such that different symbols may be represented by bit
+         sequences of different lengths, but a parser can always parse
+         an encoded string unambiguously symbol-by-symbol.
+
+         We define a prefix code in terms of a binary tree in which the
+         two edges descending from each non-leaf node are labeled 0 and
+         1 and in which the leaf nodes correspond one-for-one with (are
+         labeled with) the symbols of the alphabet; then the code for a
+         symbol is the sequence of 0's and 1's on the edges leading from
+         the root to the leaf labeled with that symbol.  For example:
+
+
+
+
+
+
+
+
+
+
+
+Deutsch                      Informational                      [Page 6]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+                          /\              Symbol    Code
+                         0  1             ------    ----
+                        /    \                A      00
+                       /\     B               B       1
+                      0  1                    C     011
+                     /    \                   D     010
+                    A     /\
+                         0  1
+                        /    \
+                       D      C
+
+         A parser can decode the next symbol from an encoded input
+         stream by walking down the tree from the root, at each step
+         choosing the edge corresponding to the next input bit.
+
+         Given an alphabet with known symbol frequencies, the Huffman
+         algorithm allows the construction of an optimal prefix code
+         (one which represents strings with those symbol frequencies
+         using the fewest bits of any possible prefix codes for that
+         alphabet).  Such a code is called a Huffman code.  (See
+         reference [1] in Chapter 5, references for additional
+         information on Huffman codes.)
+
+         Note that in the "deflate" format, the Huffman codes for the
+         various alphabets must not exceed certain maximum code lengths.
+         This constraint complicates the algorithm for computing code
+         lengths from symbol frequencies.  Again, see Chapter 5,
+         references for details.
+
+      3.2.2. Use of Huffman coding in the "deflate" format
+
+         The Huffman codes used for each alphabet in the "deflate"
+         format have two additional rules:
+
+             * All codes of a given bit length have lexicographically
+               consecutive values, in the same order as the symbols
+               they represent;
+
+             * Shorter codes lexicographically precede longer codes.
+
+
+
+
+
+
+
+
+
+
+
+
+Deutsch                      Informational                      [Page 7]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+         We could recode the example above to follow this rule as
+         follows, assuming that the order of the alphabet is ABCD:
+
+            Symbol  Code
+            ------  ----
+            A       10
+            B       0
+            C       110
+            D       111
+
+         I.e., 0 precedes 10 which precedes 11x, and 110 and 111 are
+         lexicographically consecutive.
+
+         Given this rule, we can define the Huffman code for an alphabet
+         just by giving the bit lengths of the codes for each symbol of
+         the alphabet in order; this is sufficient to determine the
+         actual codes.  In our example, the code is completely defined
+         by the sequence of bit lengths (2, 1, 3, 3).  The following
+         algorithm generates the codes as integers, intended to be read
+         from most- to least-significant bit.  The code lengths are
+         initially in tree[I].Len; the codes are produced in
+         tree[I].Code.
+
+         1)  Count the number of codes for each code length.  Let
+             bl_count[N] be the number of codes of length N, N >= 1.
+
+         2)  Find the numerical value of the smallest code for each
+             code length:
+
+                code = 0;
+                bl_count[0] = 0;
+                for (bits = 1; bits <= MAX_BITS; bits++) {
+                    code = (code + bl_count[bits-1]) << 1;
+                    next_code[bits] = code;
+                }
+
+         3)  Assign numerical values to all codes, using consecutive
+             values for all codes of the same length with the base
+             values determined at step 2. Codes that are never used
+             (which have a bit length of zero) must not be assigned a
+             value.
+
+                for (n = 0;  n <= max_code; n++) {
+                    len = tree[n].Len;
+                    if (len != 0) {
+                        tree[n].Code = next_code[len];
+                        next_code[len]++;
+                    }
+
+
+
+Deutsch                      Informational                      [Page 8]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+                }
+
+         Example:
+
+         Consider the alphabet ABCDEFGH, with bit lengths (3, 3, 3, 3,
+         3, 2, 4, 4).  After step 1, we have:
+
+            N      bl_count[N]
+            -      -----------
+            2      1
+            3      5
+            4      2
+
+         Step 2 computes the following next_code values:
+
+            N      next_code[N]
+            -      ------------
+            1      0
+            2      0
+            3      2
+            4      14
+
+         Step 3 produces the following code values:
+
+            Symbol Length   Code
+            ------ ------   ----
+            A       3        010
+            B       3        011
+            C       3        100
+            D       3        101
+            E       3        110
+            F       2         00
+            G       4       1110
+            H       4       1111
+
+      3.2.3. Details of block format
+
+         Each block of compressed data begins with 3 header bits
+         containing the following data:
+
+            first bit       BFINAL
+            next 2 bits     BTYPE
+
+         Note that the header bits do not necessarily begin on a byte
+         boundary, since a block does not necessarily occupy an integral
+         number of bytes.
+
+
+
+
+
+Deutsch                      Informational                      [Page 9]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+         BFINAL is set if and only if this is the last block of the data
+         set.
+
+         BTYPE specifies how the data are compressed, as follows:
+
+            00 - no compression
+            01 - compressed with fixed Huffman codes
+            10 - compressed with dynamic Huffman codes
+            11 - reserved (error)
+
+         The only difference between the two compressed cases is how the
+         Huffman codes for the literal/length and distance alphabets are
+         defined.
+
+         In all cases, the decoding algorithm for the actual data is as
+         follows:
+
+            do
+               read block header from input stream.
+               if stored with no compression
+                  skip any remaining bits in current partially
+                     processed byte
+                  read LEN and NLEN (see next section)
+                  copy LEN bytes of data to output
+               otherwise
+                  if compressed with dynamic Huffman codes
+                     read representation of code trees (see
+                        subsection below)
+                  loop (until end of block code recognized)
+                     decode literal/length value from input stream
+                     if value < 256
+                        copy value (literal byte) to output stream
+                     otherwise
+                        if value = end of block (256)
+                           break from loop
+                        otherwise (value = 257..285)
+                           decode distance from input stream
+
+                           move backwards distance bytes in the output
+                           stream, and copy length bytes from this
+                           position to the output stream.
+                  end loop
+            while not last block
+
+         Note that a duplicated string reference may refer to a string
+         in a previous block; i.e., the backward distance may cross one
+         or more block boundaries.  However a distance cannot refer past
+         the beginning of the output stream.  (An application using a
+
+
+
+Deutsch                      Informational                     [Page 10]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+         preset dictionary might discard part of the output stream; a
+         distance can refer to that part of the output stream anyway)
+         Note also that the referenced string may overlap the current
+         position; for example, if the last 2 bytes decoded have values
+         X and Y, a string reference with <length = 5, distance = 2>
+         adds X,Y,X,Y,X to the output stream.
+
+         We now specify each compression method in turn.
+
+      3.2.4. Non-compressed blocks (BTYPE=00)
+
+         Any bits of input up to the next byte boundary are ignored.
+         The rest of the block consists of the following information:
+
+              0   1   2   3   4...
+            +---+---+---+---+================================+
+            |  LEN  | NLEN  |... LEN bytes of literal data...|
+            +---+---+---+---+================================+
+
+         LEN is the number of data bytes in the block.  NLEN is the
+         one's complement of LEN.
+
+      3.2.5. Compressed blocks (length and distance codes)
+
+         As noted above, encoded data blocks in the "deflate" format
+         consist of sequences of symbols drawn from three conceptually
+         distinct alphabets: either literal bytes, from the alphabet of
+         byte values (0..255), or <length, backward distance> pairs,
+         where the length is drawn from (3..258) and the distance is
+         drawn from (1..32,768).  In fact, the literal and length
+         alphabets are merged into a single alphabet (0..285), where
+         values 0..255 represent literal bytes, the value 256 indicates
+         end-of-block, and values 257..285 represent length codes
+         (possibly in conjunction with extra bits following the symbol
+         code) as follows:
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Deutsch                      Informational                     [Page 11]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+                 Extra               Extra               Extra
+            Code Bits Length(s) Code Bits Lengths   Code Bits Length(s)
+            ---- ---- ------     ---- ---- -------   ---- ---- -------
+             257   0     3       267   1   15,16     277   4   67-82
+             258   0     4       268   1   17,18     278   4   83-98
+             259   0     5       269   2   19-22     279   4   99-114
+             260   0     6       270   2   23-26     280   4  115-130
+             261   0     7       271   2   27-30     281   5  131-162
+             262   0     8       272   2   31-34     282   5  163-194
+             263   0     9       273   3   35-42     283   5  195-226
+             264   0    10       274   3   43-50     284   5  227-257
+             265   1  11,12      275   3   51-58     285   0    258
+             266   1  13,14      276   3   59-66
+
+         The extra bits should be interpreted as a machine integer
+         stored with the most-significant bit first, e.g., bits 1110
+         represent the value 14.
+
+                  Extra           Extra               Extra
+             Code Bits Dist  Code Bits   Dist     Code Bits Distance
+             ---- ---- ----  ---- ----  ------    ---- ---- --------
+               0   0    1     10   4     33-48    20    9   1025-1536
+               1   0    2     11   4     49-64    21    9   1537-2048
+               2   0    3     12   5     65-96    22   10   2049-3072
+               3   0    4     13   5     97-128   23   10   3073-4096
+               4   1   5,6    14   6    129-192   24   11   4097-6144
+               5   1   7,8    15   6    193-256   25   11   6145-8192
+               6   2   9-12   16   7    257-384   26   12  8193-12288
+               7   2  13-16   17   7    385-512   27   12 12289-16384
+               8   3  17-24   18   8    513-768   28   13 16385-24576
+               9   3  25-32   19   8   769-1024   29   13 24577-32768
+
+      3.2.6. Compression with fixed Huffman codes (BTYPE=01)
+
+         The Huffman codes for the two alphabets are fixed, and are not
+         represented explicitly in the data.  The Huffman code lengths
+         for the literal/length alphabet are:
+
+                   Lit Value    Bits        Codes
+                   ---------    ----        -----
+                     0 - 143     8          00110000 through
+                                            10111111
+                   144 - 255     9          110010000 through
+                                            111111111
+                   256 - 279     7          0000000 through
+                                            0010111
+                   280 - 287     8          11000000 through
+                                            11000111
+
+
+
+Deutsch                      Informational                     [Page 12]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+         The code lengths are sufficient to generate the actual codes,
+         as described above; we show the codes in the table for added
+         clarity.  Literal/length values 286-287 will never actually
+         occur in the compressed data, but participate in the code
+         construction.
+
+         Distance codes 0-31 are represented by (fixed-length) 5-bit
+         codes, with possible additional bits as shown in the table
+         shown in Paragraph 3.2.5, above.  Note that distance codes 30-
+         31 will never actually occur in the compressed data.
+
+      3.2.7. Compression with dynamic Huffman codes (BTYPE=10)
+
+         The Huffman codes for the two alphabets appear in the block
+         immediately after the header bits and before the actual
+         compressed data, first the literal/length code and then the
+         distance code.  Each code is defined by a sequence of code
+         lengths, as discussed in Paragraph 3.2.2, above.  For even
+         greater compactness, the code length sequences themselves are
+         compressed using a Huffman code.  The alphabet for code lengths
+         is as follows:
+
+               0 - 15: Represent code lengths of 0 - 15
+                   16: Copy the previous code length 3 - 6 times.
+                       The next 2 bits indicate repeat length
+                             (0 = 3, ... , 3 = 6)
+                          Example:  Codes 8, 16 (+2 bits 11),
+                                    16 (+2 bits 10) will expand to
+                                    12 code lengths of 8 (1 + 6 + 5)
+                   17: Repeat a code length of 0 for 3 - 10 times.
+                       (3 bits of length)
+                   18: Repeat a code length of 0 for 11 - 138 times
+                       (7 bits of length)
+
+         A code length of 0 indicates that the corresponding symbol in
+         the literal/length or distance alphabet will not occur in the
+         block, and should not participate in the Huffman code
+         construction algorithm given earlier.  If only one distance
+         code is used, it is encoded using one bit, not zero bits; in
+         this case there is a single code length of one, with one unused
+         code.  One distance code of zero bits means that there are no
+         distance codes used at all (the data is all literals).
+
+         We can now define the format of the block:
+
+               5 Bits: HLIT, # of Literal/Length codes - 257 (257 - 286)
+               5 Bits: HDIST, # of Distance codes - 1        (1 - 32)
+               4 Bits: HCLEN, # of Code Length codes - 4     (4 - 19)
+
+
+
+Deutsch                      Informational                     [Page 13]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+               (HCLEN + 4) x 3 bits: code lengths for the code length
+                  alphabet given just above, in the order: 16, 17, 18,
+                  0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
+
+                  These code lengths are interpreted as 3-bit integers
+                  (0-7); as above, a code length of 0 means the
+                  corresponding symbol (literal/length or distance code
+                  length) is not used.
+
+               HLIT + 257 code lengths for the literal/length alphabet,
+                  encoded using the code length Huffman code
+
+               HDIST + 1 code lengths for the distance alphabet,
+                  encoded using the code length Huffman code
+
+               The actual compressed data of the block,
+                  encoded using the literal/length and distance Huffman
+                  codes
+
+               The literal/length symbol 256 (end of data),
+                  encoded using the literal/length Huffman code
+
+         The code length repeat codes can cross from HLIT + 257 to the
+         HDIST + 1 code lengths.  In other words, all code lengths form
+         a single sequence of HLIT + HDIST + 258 values.
+
+   3.3. Compliance
+
+      A compressor may limit further the ranges of values specified in
+      the previous section and still be compliant; for example, it may
+      limit the range of backward pointers to some value smaller than
+      32K.  Similarly, a compressor may limit the size of blocks so that
+      a compressible block fits in memory.
+
+      A compliant decompressor must accept the full range of possible
+      values defined in the previous section, and must accept blocks of
+      arbitrary size.
+
+4. Compression algorithm details
+
+   While it is the intent of this document to define the "deflate"
+   compressed data format without reference to any particular
+   compression algorithm, the format is related to the compressed
+   formats produced by LZ77 (Lempel-Ziv 1977, see reference [2] below);
+   since many variations of LZ77 are patented, it is strongly
+   recommended that the implementor of a compressor follow the general
+   algorithm presented here, which is known not to be patented per se.
+   The material in this section is not part of the definition of the
+
+
+
+Deutsch                      Informational                     [Page 14]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+   specification per se, and a compressor need not follow it in order to
+   be compliant.
+
+   The compressor terminates a block when it determines that starting a
+   new block with fresh trees would be useful, or when the block size
+   fills up the compressor's block buffer.
+
+   The compressor uses a chained hash table to find duplicated strings,
+   using a hash function that operates on 3-byte sequences.  At any
+   given point during compression, let XYZ be the next 3 input bytes to
+   be examined (not necessarily all different, of course).  First, the
+   compressor examines the hash chain for XYZ.  If the chain is empty,
+   the compressor simply writes out X as a literal byte and advances one
+   byte in the input.  If the hash chain is not empty, indicating that
+   the sequence XYZ (or, if we are unlucky, some other 3 bytes with the
+   same hash function value) has occurred recently, the compressor
+   compares all strings on the XYZ hash chain with the actual input data
+   sequence starting at the current point, and selects the longest
+   match.
+
+   The compressor searches the hash chains starting with the most recent
+   strings, to favor small distances and thus take advantage of the
+   Huffman encoding.  The hash chains are singly linked. There are no
+   deletions from the hash chains; the algorithm simply discards matches
+   that are too old.  To avoid a worst-case situation, very long hash
+   chains are arbitrarily truncated at a certain length, determined by a
+   run-time parameter.
+
+   To improve overall compression, the compressor optionally defers the
+   selection of matches ("lazy matching"): after a match of length N has
+   been found, the compressor searches for a longer match starting at
+   the next input byte.  If it finds a longer match, it truncates the
+   previous match to a length of one (thus producing a single literal
+   byte) and then emits the longer match.  Otherwise, it emits the
+   original match, and, as described above, advances N bytes before
+   continuing.
+
+   Run-time parameters also control this "lazy match" procedure.  If
+   compression ratio is most important, the compressor attempts a
+   complete second search regardless of the length of the first match.
+   In the normal case, if the current match is "long enough", the
+   compressor reduces the search for a longer match, thus speeding up
+   the process.  If speed is most important, the compressor inserts new
+   strings in the hash table only when no match was found, or when the
+   match is not "too long".  This degrades the compression ratio but
+   saves time since there are both fewer insertions and fewer searches.
+
+
+
+
+
+Deutsch                      Informational                     [Page 15]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+5. References
+
+   [1] Huffman, D. A., "A Method for the Construction of Minimum
+       Redundancy Codes", Proceedings of the Institute of Radio
+       Engineers, September 1952, Volume 40, Number 9, pp. 1098-1101.
+
+   [2] Ziv J., Lempel A., "A Universal Algorithm for Sequential Data
+       Compression", IEEE Transactions on Information Theory, Vol. 23,
+       No. 3, pp. 337-343.
+
+   [3] Gailly, J.-L., and Adler, M., ZLIB documentation and sources,
+       available in ftp://ftp.uu.net/pub/archiving/zip/doc/
+
+   [4] Gailly, J.-L., and Adler, M., GZIP documentation and sources,
+       available as gzip-*.tar in ftp://prep.ai.mit.edu/pub/gnu/
+
+   [5] Schwartz, E. S., and Kallick, B. "Generating a canonical prefix
+       encoding." Comm. ACM, 7,3 (Mar. 1964), pp. 166-169.
+
+   [6] Hirschberg and Lelewer, "Efficient decoding of prefix codes,"
+       Comm. ACM, 33,4, April 1990, pp. 449-459.
+
+6. Security Considerations
+
+   Any data compression method involves the reduction of redundancy in
+   the data.  Consequently, any corruption of the data is likely to have
+   severe effects and be difficult to correct.  Uncompressed text, on
+   the other hand, will probably still be readable despite the presence
+   of some corrupted bytes.
+
+   It is recommended that systems using this data format provide some
+   means of validating the integrity of the compressed data.  See
+   reference [3], for example.
+
+7. Source code
+
+   Source code for a C language implementation of a "deflate" compliant
+   compressor and decompressor is available within the zlib package at
+   ftp://ftp.uu.net/pub/archiving/zip/zlib/.
+
+8. Acknowledgements
+
+   Trademarks cited in this document are the property of their
+   respective owners.
+
+   Phil Katz designed the deflate format.  Jean-Loup Gailly and Mark
+   Adler wrote the related software described in this specification.
+   Glenn Randers-Pehrson converted this document to RFC and HTML format.
+
+
+
+Deutsch                      Informational                     [Page 16]
+
+RFC 1951      DEFLATE Compressed Data Format Specification      May 1996
+
+
+9. Author's Address
+
+   L. Peter Deutsch
+   Aladdin Enterprises
+   203 Santa Margarita Ave.
+   Menlo Park, CA 94025
+
+   Phone: (415) 322-0103 (AM only)
+   FAX:   (415) 322-1734
+   EMail: <ghost@aladdin.com>
+
+   Questions about the technical content of this specification can be
+   sent by email to:
+
+   Jean-Loup Gailly <gzip@prep.ai.mit.edu> and
+   Mark Adler <madler@alumni.caltech.edu>
+
+   Editorial comments on this specification can be sent by email to:
+
+   L. Peter Deutsch <ghost@aladdin.com> and
+   Glenn Randers-Pehrson <randeg@alumni.rpi.edu>
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Deutsch                      Informational                     [Page 17]
+
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+
+
+
+
+
+
+Network Working Group                                         P. Deutsch
+Request for Comments: 1952                           Aladdin Enterprises
+Category: Informational                                         May 1996
+
+
+               GZIP file format specification version 4.3
+
+Status of This Memo
+
+   This memo provides information for the Internet community.  This memo
+   does not specify an Internet standard of any kind.  Distribution of
+   this memo is unlimited.
+
+IESG Note:
+
+   The IESG takes no position on the validity of any Intellectual
+   Property Rights statements contained in this document.
+
+Notices
+
+   Copyright (c) 1996 L. Peter Deutsch
+
+   Permission is granted to copy and distribute this document for any
+   purpose and without charge, including translations into other
+   languages and incorporation into compilations, provided that the
+   copyright notice and this notice are preserved, and that any
+   substantive changes or deletions from the original are clearly
+   marked.
+
+   A pointer to the latest version of this and related documentation in
+   HTML format can be found at the URL
+   <ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html>.
+
+Abstract
+
+   This specification defines a lossless compressed data format that is
+   compatible with the widely used GZIP utility.  The format includes a
+   cyclic redundancy check value for detecting data corruption.  The
+   format presently uses the DEFLATE method of compression but can be
+   easily extended to use other compression methods.  The format can be
+   implemented readily in a manner not covered by patents.
+
+
+
+
+
+
+
+
+
+
+Deutsch                      Informational                      [Page 1]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+Table of Contents
+
+   1. Introduction ................................................... 2
+      1.1. Purpose ................................................... 2
+      1.2. Intended audience ......................................... 3
+      1.3. Scope ..................................................... 3
+      1.4. Compliance ................................................ 3
+      1.5. Definitions of terms and conventions used ................. 3
+      1.6. Changes from previous versions ............................ 3
+   2. Detailed specification ......................................... 4
+      2.1. Overall conventions ....................................... 4
+      2.2. File format ............................................... 5
+      2.3. Member format ............................................. 5
+          2.3.1. Member header and trailer ........................... 6
+              2.3.1.1. Extra field ................................... 8
+              2.3.1.2. Compliance .................................... 9
+      3. References .................................................. 9
+      4. Security Considerations .................................... 10
+      5. Acknowledgements ........................................... 10
+      6. Author's Address ........................................... 10
+      7. Appendix: Jean-Loup Gailly's gzip utility .................. 11
+      8. Appendix: Sample CRC Code .................................. 11
+
+1. Introduction
+
+   1.1. Purpose
+
+      The purpose of this specification is to define a lossless
+      compressed data format that:
+
+          * Is independent of CPU type, operating system, file system,
+            and character set, and hence can be used for interchange;
+          * Can compress or decompress a data stream (as opposed to a
+            randomly accessible file) to produce another data stream,
+            using only an a priori bounded amount of intermediate
+            storage, and hence can be used in data communications or
+            similar structures such as Unix filters;
+          * Compresses data with efficiency comparable to the best
+            currently available general-purpose compression methods,
+            and in particular considerably better than the "compress"
+            program;
+          * Can be implemented readily in a manner not covered by
+            patents, and hence can be practiced freely;
+          * Is compatible with the file format produced by the current
+            widely used gzip utility, in that conforming decompressors
+            will be able to read data produced by the existing gzip
+            compressor.
+
+
+
+
+Deutsch                      Informational                      [Page 2]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+      The data format defined by this specification does not attempt to:
+
+          * Provide random access to compressed data;
+          * Compress specialized data (e.g., raster graphics) as well as
+            the best currently available specialized algorithms.
+
+   1.2. Intended audience
+
+      This specification is intended for use by implementors of software
+      to compress data into gzip format and/or decompress data from gzip
+      format.
+
+      The text of the specification assumes a basic background in
+      programming at the level of bits and other primitive data
+      representations.
+
+   1.3. Scope
+
+      The specification specifies a compression method and a file format
+      (the latter assuming only that a file can store a sequence of
+      arbitrary bytes).  It does not specify any particular interface to
+      a file system or anything about character sets or encodings
+      (except for file names and comments, which are optional).
+
+   1.4. Compliance
+
+      Unless otherwise indicated below, a compliant decompressor must be
+      able to accept and decompress any file that conforms to all the
+      specifications presented here; a compliant compressor must produce
+      files that conform to all the specifications presented here.  The
+      material in the appendices is not part of the specification per se
+      and is not relevant to compliance.
+
+   1.5. Definitions of terms and conventions used
+
+      byte: 8 bits stored or transmitted as a unit (same as an octet).
+      (For this specification, a byte is exactly 8 bits, even on
+      machines which store a character on a number of bits different
+      from 8.)  See below for the numbering of bits within a byte.
+
+   1.6. Changes from previous versions
+
+      There have been no technical changes to the gzip format since
+      version 4.1 of this specification.  In version 4.2, some
+      terminology was changed, and the sample CRC code was rewritten for
+      clarity and to eliminate the requirement for the caller to do pre-
+      and post-conditioning.  Version 4.3 is a conversion of the
+      specification to RFC style.
+
+
+
+Deutsch                      Informational                      [Page 3]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+2. Detailed specification
+
+   2.1. Overall conventions
+
+      In the diagrams below, a box like this:
+
+         +---+
+         |   | <-- the vertical bars might be missing
+         +---+
+
+      represents one byte; a box like this:
+
+         +==============+
+         |              |
+         +==============+
+
+      represents a variable number of bytes.
+
+      Bytes stored within a computer do not have a "bit order", since
+      they are always treated as a unit.  However, a byte considered as
+      an integer between 0 and 255 does have a most- and least-
+      significant bit, and since we write numbers with the most-
+      significant digit on the left, we also write bytes with the most-
+      significant bit on the left.  In the diagrams below, we number the
+      bits of a byte so that bit 0 is the least-significant bit, i.e.,
+      the bits are numbered:
+
+         +--------+
+         |76543210|
+         +--------+
+
+      This document does not address the issue of the order in which
+      bits of a byte are transmitted on a bit-sequential medium, since
+      the data format described here is byte- rather than bit-oriented.
+
+      Within a computer, a number may occupy multiple bytes.  All
+      multi-byte numbers in the format described here are stored with
+      the least-significant byte first (at the lower memory address).
+      For example, the decimal number 520 is stored as:
+
+             0        1
+         +--------+--------+
+         |00001000|00000010|
+         +--------+--------+
+          ^        ^
+          |        |
+          |        + more significant byte = 2 x 256
+          + less significant byte = 8
+
+
+
+Deutsch                      Informational                      [Page 4]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+   2.2. File format
+
+      A gzip file consists of a series of "members" (compressed data
+      sets).  The format of each member is specified in the following
+      section.  The members simply appear one after another in the file,
+      with no additional information before, between, or after them.
+
+   2.3. Member format
+
+      Each member has the following structure:
+
+         +---+---+---+---+---+---+---+---+---+---+
+         |ID1|ID2|CM |FLG|     MTIME     |XFL|OS | (more-->)
+         +---+---+---+---+---+---+---+---+---+---+
+
+      (if FLG.FEXTRA set)
+
+         +---+---+=================================+
+         | XLEN  |...XLEN bytes of "extra field"...| (more-->)
+         +---+---+=================================+
+
+      (if FLG.FNAME set)
+
+         +=========================================+
+         |...original file name, zero-terminated...| (more-->)
+         +=========================================+
+
+      (if FLG.FCOMMENT set)
+
+         +===================================+
+         |...file comment, zero-terminated...| (more-->)
+         +===================================+
+
+      (if FLG.FHCRC set)
+
+         +---+---+
+         | CRC16 |
+         +---+---+
+
+         +=======================+
+         |...compressed blocks...| (more-->)
+         +=======================+
+
+           0   1   2   3   4   5   6   7
+         +---+---+---+---+---+---+---+---+
+         |     CRC32     |     ISIZE     |
+         +---+---+---+---+---+---+---+---+
+
+
+
+
+Deutsch                      Informational                      [Page 5]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+      2.3.1. Member header and trailer
+
+         ID1 (IDentification 1)
+         ID2 (IDentification 2)
+            These have the fixed values ID1 = 31 (0x1f, \037), ID2 = 139
+            (0x8b, \213), to identify the file as being in gzip format.
+
+         CM (Compression Method)
+            This identifies the compression method used in the file.  CM
+            = 0-7 are reserved.  CM = 8 denotes the "deflate"
+            compression method, which is the one customarily used by
+            gzip and which is documented elsewhere.
+
+         FLG (FLaGs)
+            This flag byte is divided into individual bits as follows:
+
+               bit 0   FTEXT
+               bit 1   FHCRC
+               bit 2   FEXTRA
+               bit 3   FNAME
+               bit 4   FCOMMENT
+               bit 5   reserved
+               bit 6   reserved
+               bit 7   reserved
+
+            If FTEXT is set, the file is probably ASCII text.  This is
+            an optional indication, which the compressor may set by
+            checking a small amount of the input data to see whether any
+            non-ASCII characters are present.  In case of doubt, FTEXT
+            is cleared, indicating binary data. For systems which have
+            different file formats for ascii text and binary data, the
+            decompressor can use FTEXT to choose the appropriate format.
+            We deliberately do not specify the algorithm used to set
+            this bit, since a compressor always has the option of
+            leaving it cleared and a decompressor always has the option
+            of ignoring it and letting some other program handle issues
+            of data conversion.
+
+            If FHCRC is set, a CRC16 for the gzip header is present,
+            immediately before the compressed data. The CRC16 consists
+            of the two least significant bytes of the CRC32 for all
+            bytes of the gzip header up to and not including the CRC16.
+            [The FHCRC bit was never set by versions of gzip up to
+            1.2.4, even though it was documented with a different
+            meaning in gzip 1.2.4.]
+
+            If FEXTRA is set, optional extra fields are present, as
+            described in a following section.
+
+
+
+Deutsch                      Informational                      [Page 6]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+            If FNAME is set, an original file name is present,
+            terminated by a zero byte.  The name must consist of ISO
+            8859-1 (LATIN-1) characters; on operating systems using
+            EBCDIC or any other character set for file names, the name
+            must be translated to the ISO LATIN-1 character set.  This
+            is the original name of the file being compressed, with any
+            directory components removed, and, if the file being
+            compressed is on a file system with case insensitive names,
+            forced to lower case. There is no original file name if the
+            data was compressed from a source other than a named file;
+            for example, if the source was stdin on a Unix system, there
+            is no file name.
+
+            If FCOMMENT is set, a zero-terminated file comment is
+            present.  This comment is not interpreted; it is only
+            intended for human consumption.  The comment must consist of
+            ISO 8859-1 (LATIN-1) characters.  Line breaks should be
+            denoted by a single line feed character (10 decimal).
+
+            Reserved FLG bits must be zero.
+
+         MTIME (Modification TIME)
+            This gives the most recent modification time of the original
+            file being compressed.  The time is in Unix format, i.e.,
+            seconds since 00:00:00 GMT, Jan.  1, 1970.  (Note that this
+            may cause problems for MS-DOS and other systems that use
+            local rather than Universal time.)  If the compressed data
+            did not come from a file, MTIME is set to the time at which
+            compression started.  MTIME = 0 means no time stamp is
+            available.
+
+         XFL (eXtra FLags)
+            These flags are available for use by specific compression
+            methods.  The "deflate" method (CM = 8) sets these flags as
+            follows:
+
+               XFL = 2 - compressor used maximum compression,
+                         slowest algorithm
+               XFL = 4 - compressor used fastest algorithm
+
+         OS (Operating System)
+            This identifies the type of file system on which compression
+            took place.  This may be useful in determining end-of-line
+            convention for text files.  The currently defined values are
+            as follows:
+
+
+
+
+
+
+Deutsch                      Informational                      [Page 7]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+                 0 - FAT filesystem (MS-DOS, OS/2, NT/Win32)
+                 1 - Amiga
+                 2 - VMS (or OpenVMS)
+                 3 - Unix
+                 4 - VM/CMS
+                 5 - Atari TOS
+                 6 - HPFS filesystem (OS/2, NT)
+                 7 - Macintosh
+                 8 - Z-System
+                 9 - CP/M
+                10 - TOPS-20
+                11 - NTFS filesystem (NT)
+                12 - QDOS
+                13 - Acorn RISCOS
+               255 - unknown
+
+         XLEN (eXtra LENgth)
+            If FLG.FEXTRA is set, this gives the length of the optional
+            extra field.  See below for details.
+
+         CRC32 (CRC-32)
+            This contains a Cyclic Redundancy Check value of the
+            uncompressed data computed according to CRC-32 algorithm
+            used in the ISO 3309 standard and in section 8.1.1.6.2 of
+            ITU-T recommendation V.42.  (See http://www.iso.ch for
+            ordering ISO documents. See gopher://info.itu.ch for an
+            online version of ITU-T V.42.)
+
+         ISIZE (Input SIZE)
+            This contains the size of the original (uncompressed) input
+            data modulo 2^32.
+
+      2.3.1.1. Extra field
+
+         If the FLG.FEXTRA bit is set, an "extra field" is present in
+         the header, with total length XLEN bytes.  It consists of a
+         series of subfields, each of the form:
+
+            +---+---+---+---+==================================+
+            |SI1|SI2|  LEN  |... LEN bytes of subfield data ...|
+            +---+---+---+---+==================================+
+
+         SI1 and SI2 provide a subfield ID, typically two ASCII letters
+         with some mnemonic value.  Jean-Loup Gailly
+         <gzip@prep.ai.mit.edu> is maintaining a registry of subfield
+         IDs; please send him any subfield ID you wish to use.  Subfield
+         IDs with SI2 = 0 are reserved for future use.  The following
+         IDs are currently defined:
+
+
+
+Deutsch                      Informational                      [Page 8]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+            SI1         SI2         Data
+            ----------  ----------  ----
+            0x41 ('A')  0x70 ('P')  Apollo file type information
+
+         LEN gives the length of the subfield data, excluding the 4
+         initial bytes.
+
+      2.3.1.2. Compliance
+
+         A compliant compressor must produce files with correct ID1,
+         ID2, CM, CRC32, and ISIZE, but may set all the other fields in
+         the fixed-length part of the header to default values (255 for
+         OS, 0 for all others).  The compressor must set all reserved
+         bits to zero.
+
+         A compliant decompressor must check ID1, ID2, and CM, and
+         provide an error indication if any of these have incorrect
+         values.  It must examine FEXTRA/XLEN, FNAME, FCOMMENT and FHCRC
+         at least so it can skip over the optional fields if they are
+         present.  It need not examine any other part of the header or
+         trailer; in particular, a decompressor may ignore FTEXT and OS
+         and always produce binary output, and still be compliant.  A
+         compliant decompressor must give an error indication if any
+         reserved bit is non-zero, since such a bit could indicate the
+         presence of a new field that would cause subsequent data to be
+         interpreted incorrectly.
+
+3. References
+
+   [1] "Information Processing - 8-bit single-byte coded graphic
+       character sets - Part 1: Latin alphabet No.1" (ISO 8859-1:1987).
+       The ISO 8859-1 (Latin-1) character set is a superset of 7-bit
+       ASCII. Files defining this character set are available as
+       iso_8859-1.* in ftp://ftp.uu.net/graphics/png/documents/
+
+   [2] ISO 3309
+
+   [3] ITU-T recommendation V.42
+
+   [4] Deutsch, L.P.,"DEFLATE Compressed Data Format Specification",
+       available in ftp://ftp.uu.net/pub/archiving/zip/doc/
+
+   [5] Gailly, J.-L., GZIP documentation, available as gzip-*.tar in
+       ftp://prep.ai.mit.edu/pub/gnu/
+
+   [6] Sarwate, D.V., "Computation of Cyclic Redundancy Checks via Table
+       Look-Up", Communications of the ACM, 31(8), pp.1008-1013.
+
+
+
+
+Deutsch                      Informational                      [Page 9]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+   [7] Schwaderer, W.D., "CRC Calculation", April 85 PC Tech Journal,
+       pp.118-133.
+
+   [8] ftp://ftp.adelaide.edu.au/pub/rocksoft/papers/crc_v3.txt,
+       describing the CRC concept.
+
+4. Security Considerations
+
+   Any data compression method involves the reduction of redundancy in
+   the data.  Consequently, any corruption of the data is likely to have
+   severe effects and be difficult to correct.  Uncompressed text, on
+   the other hand, will probably still be readable despite the presence
+   of some corrupted bytes.
+
+   It is recommended that systems using this data format provide some
+   means of validating the integrity of the compressed data, such as by
+   setting and checking the CRC-32 check value.
+
+5. Acknowledgements
+
+   Trademarks cited in this document are the property of their
+   respective owners.
+
+   Jean-Loup Gailly designed the gzip format and wrote, with Mark Adler,
+   the related software described in this specification.  Glenn
+   Randers-Pehrson converted this document to RFC and HTML format.
+
+6. Author's Address
+
+   L. Peter Deutsch
+   Aladdin Enterprises
+   203 Santa Margarita Ave.
+   Menlo Park, CA 94025
+
+   Phone: (415) 322-0103 (AM only)
+   FAX:   (415) 322-1734
+   EMail: <ghost@aladdin.com>
+
+   Questions about the technical content of this specification can be
+   sent by email to:
+
+   Jean-Loup Gailly <gzip@prep.ai.mit.edu> and
+   Mark Adler <madler@alumni.caltech.edu>
+
+   Editorial comments on this specification can be sent by email to:
+
+   L. Peter Deutsch <ghost@aladdin.com> and
+   Glenn Randers-Pehrson <randeg@alumni.rpi.edu>
+
+
+
+Deutsch                      Informational                     [Page 10]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+7. Appendix: Jean-Loup Gailly's gzip utility
+
+   The most widely used implementation of gzip compression, and the
+   original documentation on which this specification is based, were
+   created by Jean-Loup Gailly <gzip@prep.ai.mit.edu>.  Since this
+   implementation is a de facto standard, we mention some more of its
+   features here.  Again, the material in this section is not part of
+   the specification per se, and implementations need not follow it to
+   be compliant.
+
+   When compressing or decompressing a file, gzip preserves the
+   protection, ownership, and modification time attributes on the local
+   file system, since there is no provision for representing protection
+   attributes in the gzip file format itself.  Since the file format
+   includes a modification time, the gzip decompressor provides a
+   command line switch that assigns the modification time from the file,
+   rather than the local modification time of the compressed input, to
+   the decompressed output.
+
+8. Appendix: Sample CRC Code
+
+   The following sample code represents a practical implementation of
+   the CRC (Cyclic Redundancy Check). (See also ISO 3309 and ITU-T V.42
+   for a formal specification.)
+
+   The sample code is in the ANSI C programming language. Non C users
+   may find it easier to read with these hints:
+
+      &      Bitwise AND operator.
+      ^      Bitwise exclusive-OR operator.
+      >>     Bitwise right shift operator. When applied to an
+             unsigned quantity, as here, right shift inserts zero
+             bit(s) at the left.
+      !      Logical NOT operator.
+      ++     "n++" increments the variable n.
+      0xNNN  0x introduces a hexadecimal (base 16) constant.
+             Suffix L indicates a long value (at least 32 bits).
+
+      /* Table of CRCs of all 8-bit messages. */
+      unsigned long crc_table[256];
+
+      /* Flag: has the table been computed? Initially false. */
+      int crc_table_computed = 0;
+
+      /* Make the table for a fast CRC. */
+      void make_crc_table(void)
+      {
+        unsigned long c;
+
+
+
+Deutsch                      Informational                     [Page 11]
+
+RFC 1952             GZIP File Format Specification             May 1996
+
+
+        int n, k;
+        for (n = 0; n < 256; n++) {
+          c = (unsigned long) n;
+          for (k = 0; k < 8; k++) {
+            if (c & 1) {
+              c = 0xedb88320L ^ (c >> 1);
+            } else {
+              c = c >> 1;
+            }
+          }
+          crc_table[n] = c;
+        }
+        crc_table_computed = 1;
+      }
+
+      /*
+         Update a running crc with the bytes buf[0..len-1] and return
+       the updated crc. The crc should be initialized to zero. Pre- and
+       post-conditioning (one's complement) is performed within this
+       function so it shouldn't be done by the caller. Usage example:
+
+         unsigned long crc = 0L;
+
+         while (read_buffer(buffer, length) != EOF) {
+           crc = update_crc(crc, buffer, length);
+         }
+         if (crc != original_crc) error();
+      */
+      unsigned long update_crc(unsigned long crc,
+                      unsigned char *buf, int len)
+      {
+        unsigned long c = crc ^ 0xffffffffL;
+        int n;
+
+        if (!crc_table_computed)
+          make_crc_table();
+        for (n = 0; n < len; n++) {
+          c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
+        }
+        return c ^ 0xffffffffL;
+      }
+
+      /* Return the CRC of the bytes buf[0..len-1]. */
+      unsigned long crc(unsigned char *buf, int len)
+      {
+        return update_crc(0L, buf, len);
+      }
+
+
+
+
+Deutsch                      Informational                     [Page 12]
+
@@ -0,0 +1,107 @@
+A Fast Method for Identifying Plain Text Files
+==============================================
+
+
+Introduction
+------------
+
+Given a file coming from an unknown source, it is sometimes desirable
+to find out whether the format of that file is plain text.  Although
+this may appear like a simple task, a fully accurate detection of the
+file type requires heavy-duty semantic analysis on the file contents.
+It is, however, possible to obtain satisfactory results by employing
+various heuristics.
+
+Previous versions of PKZip and other zip-compatible compression tools
+were using a crude detection scheme: if more than 80% (4/5) of the bytes
+found in a certain buffer are within the range [7..127], the file is
+labeled as plain text, otherwise it is labeled as binary.  A prominent
+limitation of this scheme is the restriction to Latin-based alphabets.
+Other alphabets, like Greek, Cyrillic or Asian, make extensive use of
+the bytes within the range [128..255], and texts using these alphabets
+are most often misidentified by this scheme; in other words, the rate
+of false negatives is sometimes too high, which means that the recall
+is low.  Another weakness of this scheme is a reduced precision, due to
+the false positives that may occur when binary files containing large
+amounts of textual characters are misidentified as plain text.
+
+In this article we propose a new, simple detection scheme that features
+a much increased precision and a near-100% recall.  This scheme is
+designed to work on ASCII, Unicode and other ASCII-derived alphabets,
+and it handles single-byte encodings (ISO-8859, MacRoman, KOI8, etc.)
+and variable-sized encodings (ISO-2022, UTF-8, etc.).  Wider encodings
+(UCS-2/UTF-16 and UCS-4/UTF-32) are not handled, however.
+
+
+The Algorithm
+-------------
+
+The algorithm works by dividing the set of bytecodes [0..255] into three
+categories:
+- The white list of textual bytecodes:
+  9 (TAB), 10 (LF), 13 (CR), 32 (SPACE) to 255.
+- The gray list of tolerated bytecodes:
+  7 (BEL), 8 (BS), 11 (VT), 12 (FF), 26 (SUB), 27 (ESC).
+- The black list of undesired, non-textual bytecodes:
+  0 (NUL) to 6, 14 to 31.
+
+If a file contains at least one byte that belongs to the white list and
+no byte that belongs to the black list, then the file is categorized as
+plain text; otherwise, it is categorized as binary.  (The boundary case,
+when the file is empty, automatically falls into the latter category.)
+
+
+Rationale
+---------
+
+The idea behind this algorithm relies on two observations.
+
+The first observation is that, although the full range of 7-bit codes
+[0..127] is properly specified by the ASCII standard, most control
+characters in the range [0..31] are not used in practice.  The only
+widely-used, almost universally-portable control codes are 9 (TAB),
+10 (LF) and 13 (CR).  There are a few more control codes that are
+recognized on a reduced range of platforms and text viewers/editors:
+7 (BEL), 8 (BS), 11 (VT), 12 (FF), 26 (SUB) and 27 (ESC); but these
+codes are rarely (if ever) used alone, without being accompanied by
+some printable text.  Even the newer, portable text formats such as
+XML avoid using control characters outside the list mentioned here.
+
+The second observation is that most of the binary files tend to contain
+control characters, especially 0 (NUL).  Even though the older text
+detection schemes observe the presence of non-ASCII codes from the range
+[128..255], the precision rarely has to suffer if this upper range is
+labeled as textual, because the files that are genuinely binary tend to
+contain both control characters and codes from the upper range.  On the
+other hand, the upper range needs to be labeled as textual, because it
+is used by virtually all ASCII extensions.  In particular, this range is
+used for encoding non-Latin scripts.
+
+Since there is no counting involved, other than simply observing the
+presence or the absence of some byte values, the algorithm produces
+consistent results, regardless what alphabet encoding is being used.
+(If counting were involved, it could be possible to obtain different
+results on a text encoded, say, using ISO-8859-16 versus UTF-8.)
+
+There is an extra category of plain text files that are "polluted" with
+one or more black-listed codes, either by mistake or by peculiar design
+considerations.  In such cases, a scheme that tolerates a small fraction
+of black-listed codes would provide an increased recall (i.e. more true
+positives).  This, however, incurs a reduced precision overall, since
+false positives are more likely to appear in binary files that contain
+large chunks of textual data.  Furthermore, "polluted" plain text should
+be regarded as binary by general-purpose text detection schemes, because
+general-purpose text processing algorithms might not be applicable.
+Under this premise, it is safe to say that our detection method provides
+a near-100% recall.
+
+Experiments have been run on many files coming from various platforms
+and applications.  We tried plain text files, system logs, source code,
+formatted office documents, compiled object code, etc.  The results
+confirm the optimistic assumptions about the capabilities of this
+algorithm.
+
+
+--
+Cosmin Truta
+Last updated: 2006-May-28
@@ -119,7 +119,7 @@ retrieve the stack trace when script evaluation returns
 \fBTCL_ERROR\fR, like so:
 .PP
 .CS
-int code = Tcl_Eval(interp, script);
+int code = Tcl_EvalEx(interp, script, -1, 0);
 if (code == TCL_ERROR) {
    Tcl_Obj *options = \fBTcl_GetReturnOptions\fR(interp, code);
    Tcl_Obj *key = Tcl_NewStringObj("-errorinfo", -1);
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_CallWhenDeleted 3 7.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_CommandComplete 3 "" Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_Concat 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_CreateFileHandler 3 8.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_CreateInterp 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_CreateTimerHandler 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_DetachPids 3 "" Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_DictObj 3 8.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_DoWhenIdle 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_PutEnv 3 "7.5" Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -205,7 +205,7 @@ and sets \fIinterp\fR's result to an error message indicating that
 the \fBreturn\fR, \fBbreak\fR, or \fBcontinue\fR command was
 invoked in an inappropriate place.
 This means that top-level applications should never see a return code
-from \fBTcl_EvalObjEx\fR other than \fBTCL_OK\fR or \fBTCL_ERROR\fR.
+from \fBTcl_EvalObjEx\fR other then \fBTCL_OK\fR or \fBTCL_ERROR\fR.

 .SH KEYWORDS
 execute, file, global, result, script, value
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_ExprLongObj 3 8.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_FindExecutable 3 8.1 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_GetCwd 3 8.1 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_GetIndexFromObj 3 8.1 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_GetOpenFile 3 8.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_GetTime 3 8.4 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -281,7 +281,7 @@ The \fIhashKeyProc\fR member contains the address of a function called to
 calculate a hash value for the key.
 .PP
 .CS
-typedef unsigned int \fBTcl_HashKeyProc\fR(
+typedef TCL_HASH_TYPE \fBTcl_HashKeyProc\fR(
        Tcl_HashTable *\fItablePtr\fR,
        void *\fIkeyPtr\fR);
 .CE
@@ -1,7 +1,7 @@
 '\"
 '\" Copyright (c) 1998-2000 by Scriptics Corporation.
 '\" All rights reserved.
-'\" 
+'\"
 .TH Tcl_Init 3 8.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_InitStubs 3 8.1 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -23,11 +23,11 @@ Tcl interpreter handle.
 A version string consisting of one or more decimal numbers
 separated by dots.
 .AP int exact in
-Non-zero means that only the particular version specified by
+1 means that only the particular version specified by
 \fIversion\fR is acceptable.
-Zero means that versions newer than \fIversion\fR are also
+0 means that versions newer than \fIversion\fR are also
 acceptable as long as they have the same major version number
-as \fIversion\fR.
+as \fIversion\fR. Other bits have no effect.
 .BE
 .SH INTRODUCTION
 .PP
@@ -97,7 +97,7 @@ are provided by the C language standard.  The \fBTcl_WideInt\fR type is a
 typedef defined to be whatever signed integral type covers at least the
 64-bit integer range (-9223372036854775808 to 9223372036854775807).  Depending
 on the platform and the C compiler, the actual type might be
-\fBlong int\fR, \fBlong long int\fR, \fB__int64\fR, or something else.
+\fBlong int\fR, \fBlong long int\fR, \fBint64\fR, or something else.
 The \fBmp_int\fR type is a multiple-precision integer type defined
 by the LibTomMath multiple-precision integer library.
 .PP
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_LimitCheck 3 8.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Load 3 8.6 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,10 +3,10 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 '\" Note that some of these functions do not seem to belong, but they
 '\" were all introduced with the same TIP (#139)
-'\" 
+'\"
 .TH Tcl_Namespace 3 8.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,12 +4,12 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\"
-.TH Tcl_OpenTcpClient 3 8.0 Tcl "Tcl Library Procedures"
+.TH Tcl_OpenTcpClient 3 8.7 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
 '\" Note:  do not modify the .SH NAME line immediately below!
 .SH NAME
-Tcl_OpenTcpClient, Tcl_MakeTcpClientChannel, Tcl_OpenTcpServer \- procedures to open channels using TCP sockets
+Tcl_OpenTcpClient, Tcl_MakeTcpClientChannel, Tcl_OpenTcpServer, Tcl_OpenTcpServerEx \- procedures to open channels using TCP sockets
 .SH SYNOPSIS
 .nf
 \fB#include <tcl.h> \fR
@@ -23,6 +23,9 @@ Tcl_Channel
 Tcl_Channel
 \fBTcl_OpenTcpServer\fR(\fIinterp, port, myaddr, proc, clientData\fR)
 .sp
+Tcl_Channel
+\fBTcl_OpenTcpServerEx\fR(\fIinterp, service, myaddr, flags, proc, clientData\fR)
+.sp
 .SH ARGUMENTS
 .AS Tcl_TcpAcceptProc clientData
 .AP Tcl_Interp *interp in
@@ -30,6 +33,9 @@ Tcl interpreter to use for error reporting.  If non-NULL and an
 error occurs, an error message is left in the interpreter's result.
 .AP int port in
 A port number to connect to as a client or to listen on as a server.
+.AP "const char" *service in
+A string specifying the port number to connect to as a client or to listen on as
+ a server.
 .AP "const char" *host in
 A string specifying a host name or address for the remote end of the connection.
 .AP int myport in
@@ -41,6 +47,9 @@ for the local end of the connection.  If NULL, a default interface is
 chosen.
 .AP int async in
 If nonzero, the client socket is connected asynchronously to the server.
+.AP "unsigned int" flags in
+ORed combination of \fBTCL_TCPSERVER\fR flags that specify additional
+informations about the socket being created.
 .AP ClientData sock in
 Platform-specific handle for client TCP socket.
 .AP Tcl_TcpAcceptProc *proc in
@@ -130,7 +139,7 @@ for the new channel, \fIhostName\fR points to a string containing
 the name of the client host making the connection, and \fIport\fR
 will contain the client's port number.
 The new channel
-is opened for both input and output. 
+is opened for both input and output.
 If \fIproc\fR raises an error, the connection is closed automatically.
 \fIProc\fR has no return value, but if it wishes to reject the
 connection it can close \fIchannel\fR.
@@ -158,6 +167,11 @@ register it, use \fBTcl_RegisterChannel\fR.
 If one of the standard channels, \fBstdin\fR, \fBstdout\fR or \fBstderr\fR was
 previously closed, the act of creating the new channel also assigns it as a
 replacement for the standard channel.
+.SS TCL_OPENTCPSERVEREX
+.PP
+\fBTcl_OpenTcpServerEx\fR behaviour is identical to \fBTcl_OpenTcpServer\fR but
+gives more flexibility to the user by providing a mean to further customize some
+aspects of the socket via the \fIflags\fR parameter.
 .SH "PLATFORM ISSUES"
 .PP
 On Unix platforms, the socket handle is a Unix file descriptor as
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_ParseArgsObjv 3 8.6 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_Preserve 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_PrintDouble 3 8.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_RecordAndEvalObj 3 8.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_RecordAndEval 3 7.4 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_SetErrno 3 8.3 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_SetRecursionLimit 3 7.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_SignalId 3 8.3 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_Sleep 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_SplitList 3 8.0 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_SplitPath 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_StaticPackage 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH "Standard Channels" 3 7.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_StringMatch 3 8.5 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH Tcl_SubstObj 3 8.4 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -1,8 +1,8 @@
-'\" 
+'\"
 '\" Copyright (c) 1992-1999 Karl Lehenbauer and Mark Diekhans.
 '\" Copyright (c) 2000 by Scriptics Corporation.
 '\" All rights reserved.
-'\" 
+'\"
 .TH TCL_MEM_DEBUG 3 8.1 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH TclZlib 3 8.6 Tcl "Tcl Library Procedures"
 .so man.macros
 .BS
@@ -47,13 +47,6 @@ been the return value from a previous invocation of
 Returns 1 if \fIarrayName\fR is an array variable, 0 if there
 is no variable by that name or if it is a scalar variable.
 .TP
-\fBarray for {\fIkeyVariable ?valueVariable?\fB} \fIarrayName body\fR
-The first argument is a one or two element list of variable names for the
-key and value of each entry in the array.  The second argument is the
-array name to iterate over.  The third argument is the body to execute
-for each key and value returned.
-The ordering of the returned keys is undefined.
-.TP
 \fBarray get \fIarrayName\fR ?\fIpattern\fR?
 Returns a list containing pairs of elements.  The first
 element in each pair is the name of an element in \fIarrayName\fR
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH break n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH case n 7.0 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH cd n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -89,10 +89,9 @@ have 59 or 61 seconds.
 .TP
 \fIunit\fR
 One of the words, \fBseconds\fR, \fBminutes\fR, \fBhours\fR,
-\fBdays\fR, \fBweeks\fR, \fBmonths\fR, or \fByears\fR, or
-any unique prefix of such a word. Used in conjunction with \fIcount\fR
-to identify an interval of time, for example, \fI3 seconds\fR or
-\fI1 year\fR.
+\fBdays\fR, \fBweekdays\fR, \fBweeks\fR, \fBmonths\fR, or \fByears\fR.
+Used in conjunction with \fIcount\fR to identify an interval of time,
+for example, \fI3 seconds\fR or \fI1 year\fR.
 .SS "OPTIONS"
 .TP
 \fB\-base\fR time
@@ -175,8 +174,7 @@ given as its first argument.  The remaining arguments (other than the
 possible \fB\-timezone\fR, \fB\-locale\fR and \fB\-gmt\fR options)
 are integers and keywords in alternation, where the keywords are chosen
 from \fBseconds\fR, \fBminutes\fR, \fBhours\fR,
-\fBdays\fR, \fBweeks\fR, \fBmonths\fR, or \fByears\fR, or
-any unique prefix of such a word.
+\fBdays\fR, \fBweekdays\fR, \fBweeks\fR, \fBmonths\fR, or \fByears\fR.
 .PP
 Addition of seconds, minutes and hours is fairly straightforward;
 the given time increment (times sixty for minutes, or 3600 for hours)
@@ -213,7 +211,8 @@ the given time to a calendar day and time of day in the appropriate
 time zone and locale.  The requisite number of days (weeks are converted
 to days by multiplying by seven) is added to the calendar day, and
 the date and time are then converted back to a count of seconds from
-the epoch time.
+the epoch time.  The \fBweekdays\fR keyword is similar to \fBdays\fR,
+with the only difference that weekends - Saturdays and Sundays - are skipped.
 .PP
 Adding and subtracting a given number of days across the point that
 the time changes at the start or end of summer time (Daylight Saving Time)
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH close n 7.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH concat n 8.3 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH continue n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -14,7 +14,7 @@ oo::copy \- create copies of objects and classes
 .nf
 package require TclOO

-\fBoo::copy\fI sourceObject \fR?\fItargetObject\fR? ?\fItargetNamespace\fR?
+\fBoo::copy\fI sourceObject \fR?\fItargetObject\fR?
 .fi
 .BE
 .SH DESCRIPTION
@@ -22,21 +22,11 @@ package require TclOO
 The \fBoo::copy\fR command creates a copy of an object or class. It takes the
 name of the object or class to be copied, \fIsourceObject\fR, and optionally
 the name of the object or class to create, \fItargetObject\fR, which will be
-resolved relative to the current namespace if not an absolute qualified name
-and
-.VS TIP473
-\fItargetNamespace\fR which is the name of the namespace that will hold the
-internal state of the object (\fBmy\fR command, etc.); it \fImust not\fR
-refer to an existing namespace.
-If either \fItargetObject\fR or \fItargetNamespace\fR is omitted or is given
-as the empty string, a new name is chosen. Names, unless specified, are
-chosen with the same algorithm used by the \fBnew\fR method of
-\fBoo::class\fR.
-.VE TIP473
-The copied object will be of the same class as the source object, and will have 
-all its per-object methods copied. If it is a class, it will also have all the 
-class methods in the class copied, but it will not have any of its instances 
-copied.
+resolved relative to the current namespace if not an absolute qualified name.
+If \fItargetObject\fR is omitted, a new name is chosen. The copied object will
+be of the same class as the source object, and will have all its per-object
+methods copied. If it is a class, it will also have all the class methods in
+the class copied, but it will not have any of its instances copied.
 .PP
 .VS
 After the \fItargetObject\fR has been created and all definitions of its
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH coroutine n 8.6 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -437,7 +437,7 @@ puts $foo
 #    prints: \fIa b foo {a b} bar 2 baz 3\fR
 .CE
 .SH "SEE ALSO"
-append(n), array(n), foreach(n), incr(n), list(n), lappend(n), lmap(n), set(n)
+append(n), array(n), foreach(n), mapeach(n), incr(n), list(n), lappend(n), set(n)
 .SH KEYWORDS
 dictionary, create, update, lookup, iterate, filter, map
 '\" Local Variables:
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH eof n 7.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH eval n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH exit n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -17,14 +17,14 @@ expr \- Evaluate an expression
 .BE
 .SH DESCRIPTION
 .PP
-Concatenates \fIarg\fRs (adding separator spaces between them),
-evaluates the result as a Tcl expression, and returns the value.
-The operators permitted in Tcl expressions include a subset of
+Concatenates \fIarg\fRs, separated by a space, into an expression, and evaluates
+that expression, returning its value.
+The operators permitted in an expression include a subset of
 the operators permitted in C expressions.  For those operators
 common to both Tcl and C, Tcl applies the same meaning and precedence
 as the corresponding C operators.
-Expressions almost always yield numeric results
-(integer or floating-point values).
+The value of an expression is often a numeric result, either an integer or a
+floating-point value, but may also be a non-numeric value.
 For example, the expression
 .PP
 .CS
@@ -32,78 +32,68 @@ For example, the expression
 .CE
 .PP
 evaluates to 14.2.
-Tcl expressions differ from C expressions in the way that
-operands are specified.  Also, Tcl expressions support
-non-numeric operands and string comparisons, as well as some
+Expressions differ from C expressions in the way that
+operands are specified.  Expressions also support
+non-numeric operands, string comparisons, and some
 additional operators not found in C.
+.PP
+When an expression evaluates to an integer, the value is the decimal form of
+the integer, and when an expression evaluates to a floating-point number, the
+value is the form produced by the \fB%g\fR format specifier of Tcl's
+\fBformat\fR command.
 .SS OPERANDS
 .PP
-A Tcl expression consists of a combination of operands, operators,
-parentheses and commas.
-White space may be used between the operands and operators and
-parentheses (or commas); it is ignored by the expression's instructions.
-Where possible, operands are interpreted as integer values.
-Integer values may be specified in decimal (the normal case), in binary
-(if the first two characters of the operand are \fB0b\fR), in octal
-(if the first two characters of the operand are \fB0o\fR), or in hexadecimal
-(if the first two characters of the operand are \fB0x\fR).  For
-compatibility with older Tcl releases, an octal integer value is also
-indicated simply when the first character of the operand is \fB0\fR,
-whether or not the second character is also \fBo\fR.
-If an operand does not have one of the integer formats given
-above, then it is treated as a floating-point number if that is
-possible.  Floating-point numbers may be specified in any of several
-common formats making use of the decimal digits, the decimal point \fB.\fR,
-the characters \fBe\fR or \fBE\fR indicating scientific notation, and
-the sign characters \fB+\fR or \fB\-\fR.  For example, all of the
-following are valid floating-point numbers:  2.1, 3., 6e4, 7.91e+16.
-Also recognized as floating point values are the strings \fBInf\fR
-and \fBNaN\fR making use of any case for each character.
-If no numeric interpretation is possible (note that all literal
-operands that are not numeric or boolean must be quoted with either
-braces or with double quotes), then an operand is left as a string
-(and only a limited set of operators may be applied to it).
+An expression consists of a combination of operands, operators, parentheses and
+commas, possibly with whitespace between any of these elements, which is
+ignored.
+An integer operand may be specified in decimal, binary
+(the first two characters are \fB0b\fR), octal
+(the first two characters are \fB0o\fR), or hexadecimal
+(the first two characters are \fB0x\fR) form.  For
+compatibility with older Tcl releases, an operand that begins with \fB0\fR is
+interpreted as an octal integer even if the second character is not \fBo\fR.
+A floating-point number may be specified in any of several
+common decimal formats, and may use the decimal point \fB.\fR,
+\fBe\fR or \fBE\fR for scientific notation, and
+the sign characters \fB+\fR and \fB\-\fR.  The
+following are all valid floating-point numbers:  2.1, 3., 6e4, 7.91e+16.
+The strings \fBInf\fR
+and \fBNaN\fR, in any combination of case, are also recognized as floating point
+values.  An operand that doesn't have a numeric interpretation must be quoted
+with either braces or with double quotes.
 .PP
-Operands may be specified in any of the following ways:
+An operand may be specified in any of the following ways:
 .IP [1]
 As a numeric value, either integer or floating-point.
 .IP [2]
 As a boolean value, using any form understood by \fBstring is\fR
 \fBboolean\fR.
 .IP [3]
-As a Tcl variable, using standard \fB$\fR notation.
-The variable's value will be used as the operand.
+As a variable, using standard \fB$\fR notation.
+The value of the variable is then the value of the operand.
 .IP [4]
 As a string enclosed in double-quotes.
-The expression parser will perform backslash, variable, and
-command substitutions on the information between the quotes,
-and use the resulting value as the operand
+Backslash, variable, and command substitution are performed as described in
+\fBTcl\fR.
 .IP [5]
 As a string enclosed in braces.
-The characters between the open brace and matching close brace
-will be used as the operand without any substitutions.
+The operand is treated as a braced value as described in \fBTcl\fR.
 .IP [6]
 As a Tcl command enclosed in brackets.
-The command will be executed and its result will be used as
-the operand.
+Command substitution is performed as described in \fBTcl\fR.
 .IP [7]
-As a mathematical function whose arguments have any of the above
-forms for operands, such as \fBsin($x)\fR.  See \fBMATH FUNCTIONS\fR below for
+As a mathematical function such as \fBsin($x)\fR, whose arguments have any of the above
+forms for operands.  See \fBMATH FUNCTIONS\fR below for
 a discussion of how mathematical functions are handled.
 .PP
-Where the above substitutions occur (e.g. inside quoted strings), they
-are performed by the expression's instructions.
-However, the command parser may already have performed one round of
-substitution before the expression processor was called.
-As discussed below, it is usually best to enclose expressions
-in braces to prevent the command parser from performing substitutions
-on the contents.
+Because \fBexpr\fR parses and performs substitutions on values that have
+already been parsed and substituted by \fBTcl\fR, it is usually best to enclose
+expressions in braces to avoid the first round of substitutions by
+\fBTcl\fR.
 .PP
-For some examples of simple expressions, suppose the variable
-\fBa\fR has the value 3 and
-the variable \fBb\fR has the value 6.
-Then the command on the left side of each of the lines below
-will produce the value on the right side of the line:
+Below are some examples of simple expressions where the value of \fBa\fR is 3
+and the value of \fBb\fR is 6.  The command on the left side of each line
+produces the value on the right side.
 .PP
 .CS
 .ta 6c
@@ -114,34 +104,41 @@ will produce the value on the right side of the line:
 .CE
 .SS OPERATORS
 .PP
-The valid operators (most of which are also available as commands in
-the \fBtcl::mathop\fR namespace; see the \fBmathop\fR(n) manual page
-for details) are listed below, grouped in decreasing order of precedence:
+For operators having both a numeric mode and a string mode, the numeric mode is
+chosen when all operands have a numeric interpretation.  The integer
+interpretation of an operand is preferred over the floating-point
+interpretation.  To ensure string operations on arbitrary values it is generally a
+good idea to use \fBeq\fR, \fBne\fR, or the \fBstring\fR command instead of
+more versatile operators such as \fB==\fR.
+.PP
+Unless otherwise specified, operators accept non-numeric operands.  The value
+of a boolean operation is 1 if true, 0 otherwise.  See also \fBstring is\fR
+\fBboolean\fR.  The valid operators, most of which are also available as
+commands in the \fBtcl::mathop\fR namespace (see \fBmathop\fR(n)), are listed
+below, grouped in decreasing order of precedence:
 .TP 20
 \fB\-\0\0+\0\0~\0\0!\fR
 .
-Unary minus, unary plus, bit-wise NOT, logical NOT.  None of these operators
-may be applied to string operands, and bit-wise NOT may be
-applied only to integers.
+Unary minus, unary plus, bit-wise NOT, logical NOT.  These operators
+may only be applied to numeric operands, and bit-wise NOT may only be
+applied to integers.
 .TP 20
 \fB**\fR
 .
-Exponentiation.  Valid for any numeric operands.
+Exponentiation.  Valid for numeric operands.
 .TP 20
 \fB*\0\0/\0\0%\fR
 .
-Multiply, divide, remainder.  None of these operators may be
-applied to string operands, and remainder may be applied only
-to integers.
-The remainder will always have the same sign as the divisor and
-an absolute value smaller than the absolute value of the divisor.
+Multiply and divide, which are valid for numeric operands, and remainder, which
+is valid for integers.  The remainder, an absolute value smaller than the
+absolute value of the divisor, has the same sign as the divisor.
 .RS
 .PP
-When applied to integers, the division and remainder operators can be
-considered to partition the number line into a sequence of equal-sized
-adjacent non-overlapping pieces where each piece is the size of the divisor;
-the division result identifies which piece the divisor lay within, and the
-remainder result identifies where within that piece the divisor lay. A
+When applied to integers, division and remainder can be
+considered to partition the number line into a sequence of
+adjacent non-overlapping pieces, where each piece is the size of the divisor;
+the quotient identifies which piece the dividend lies within, and the
+remainder identifies where within that piece the dividend lies. A
 consequence of this is that the result of
 .QW "-57 \fB/\fR 10"
 is always -6, and the result of
@@ -151,177 +148,157 @@ is always 3.
 .TP 20
 \fB+\0\0\-\fR
 .
-Add and subtract.  Valid for any numeric operands.
+Add and subtract.  Valid for numeric operands.
 .TP 20
 \fB<<\0\0>>\fR
 .
-Left and right shift.  Valid for integer operands only.
+Left and right shift.  Valid for integers.
 A right shift always propagates the sign bit.
 .TP 20
 \fB<\0\0>\0\0<=\0\0>=\fR
 .
-Boolean less, greater, less than or equal, and greater than or equal.
-Each operator produces 1 if the condition is true, 0 otherwise.
-These operators may be applied to strings as well as numeric operands,
-in which case string comparison is used.
+Boolean less than, greater than, less than or equal, and greater than or equal.
 .TP 20
 \fB==\0\0!=\fR
 .
-Boolean equal and not equal.  Each operator produces a zero/one result.
-Valid for all operand types.
+Boolean equal and not equal.
 .TP 20
 \fBeq\0\0ne\fR
 .
-Boolean string equal and string not equal.  Each operator produces a
-zero/one result.  The operand types are interpreted only as strings.
+Boolean string equal and string not equal.
 .TP 20
 \fBin\0\0ni\fR
 .
-List containment and negated list containment.  Each operator produces
-a zero/one result and treats its first argument as a string and its
-second argument as a Tcl list.  The \fBin\fR operator indicates
-whether the first argument is a member of the second argument list;
-the \fBni\fR operator inverts the sense of the result.
+List containment and negated list containment.  The first argument is
+interpreted as a string, the second as a list.  \fBin\fR tests for membership
+in the list, and \fBni\fR is the inverse.
 .TP 20
 \fB&\fR
 .
-Bit-wise AND.  Valid for integer operands only.
+Bit-wise AND.  Valid for integer operands.
 .TP 20
 \fB^\fR
 .
-Bit-wise exclusive OR.  Valid for integer operands only.
+Bit-wise exclusive OR.  Valid for integer operands.
 .TP 20
 \fB|\fR
 .
-Bit-wise OR.  Valid for integer operands only.
+Bit-wise OR.  Valid for integer operands.
 .TP 20
 \fB&&\fR
 .
-Logical AND.  Produces a 1 result if both operands are non-zero,
-0 otherwise.
-Valid for boolean and numeric (integers or floating-point) operands only.
+Logical AND.  If both operands are true, the result is 1, or 0 otherwise.
+
 .TP 20
 \fB||\fR
 .
-Logical OR.  Produces a 0 result if both operands are zero, 1 otherwise.
-Valid for boolean and numeric (integers or floating-point) operands only.
+Logical OR.  If both operands are false, the result is 0, or 1 otherwise.
 .TP 20
 \fIx\fB?\fIy\fB:\fIz\fR
 .
-If-then-else, as in C.  If \fIx\fR
-evaluates to non-zero, then the result is the value of \fIy\fR.
-Otherwise the result is the value of \fIz\fR.
-The \fIx\fR operand must have a boolean or numeric value.
+If-then-else, as in C.  If \fIx\fR is false , the result is the value of
+\fIy\fR.  Otherwise the result is the value of \fIz\fR.
 .PP
-See the C manual for more details on the results
-produced by each operator.
-The exponentiation operator promotes types like the multiply and
-divide operators, and produces a result that is the same as the output
-of the \fBpow\fR function (after any type conversions.)
-All of the binary operators but exponentiation group left-to-right
-within the same precedence level; exponentiation groups right-to-left.  For example, the command
+The exponentiation operator promotes types in the same way that the multiply
+and divide operators do, and the result is is the same as the result of
+\fBpow\fR.
+Exponentiation groups right-to-left within a precedence level. Other binary
+operators group left-to-right.  For example, the value of
 .PP
 .CS
 \fBexpr\fR {4*2 < 7}
 .CE
 .PP
-returns 0, while
+is 0, while the value of
 .PP
 .CS
 \fBexpr\fR {2**3**2}
 .CE
 .PP
-returns 512.
+is 512.
 .PP
-The \fB&&\fR, \fB||\fR, and \fB?:\fR operators have
+As in C, \fB&&\fR, \fB||\fR, and \fB?:\fR feature
 .QW "lazy evaluation" ,
-just as in C, which means that operands are not evaluated if they are
-not needed to determine the outcome.  For example, in the command
+which means that operands are not evaluated if they are
+not needed to determine the outcome.  For example, in
 .PP
 .CS
 \fBexpr\fR {$v ? [a] : [b]}
 .CE
 .PP
-only one of
-.QW \fB[a]\fR
-or
-.QW \fB[b]\fR
-will actually be evaluated,
-depending on the value of \fB$v\fR.  Note, however, that this is
-only true if the entire expression is enclosed in braces;  otherwise
-the Tcl parser will evaluate both
-.QW \fB[a]\fR
-and
-.QW \fB[b]\fR
-before invoking the \fBexpr\fR command.
+only one of \fB[a]\fR or \fB[b]\fR is evaluated,
+depending on the value of \fB$v\fR.  This is not true of the normal Tcl parser,
+so it is normally recommended to enclose the arguments to \fBexpr\fR in braces.
+Without braces, as in
+\fBexpr\fR $v ? [a] : [b]
+both \fB[a]\fR and \fB[b]\fR are evaluated before \fBexpr\fR is even called.
+.PP
+For more details on the results
+produced by each operator, see the documentation for C.
 .SS "MATH FUNCTIONS"
 .PP
-When the expression parser encounters a mathematical function
-such as \fBsin($x)\fR, it replaces it with a call to an ordinary
-Tcl function in the \fBtcl::mathfunc\fR namespace.  The processing
-of an expression such as:
+A mathematical function such as \fBsin($x)\fR is replaced with a call to an ordinary
+Tcl command in the \fBtcl::mathfunc\fR namespace.  The evaluation
+of an expression such as
 .PP
 .CS
 \fBexpr\fR {sin($x+$y)}
 .CE
 .PP
-is the same in every way as the processing of:
+is the same in every way as the evaluation of
 .PP
 .CS
 \fBexpr\fR {[tcl::mathfunc::sin [\fBexpr\fR {$x+$y}]]}
 .CE
 .PP
-which in turn is the same as the processing of:
+which in turn is the same as the evaluation of
 .PP
 .CS
 tcl::mathfunc::sin [\fBexpr\fR {$x+$y}]
 .CE
 .PP
-The executor will search for \fBtcl::mathfunc::sin\fR using the usual
-rules for resolving functions in namespaces. Either
-\fB::tcl::mathfunc::sin\fR or \fB[namespace
-current]::tcl::mathfunc::sin\fR will satisfy the request, and others
-may as well (depending on the current \fBnamespace path\fR setting).
+\fBtcl::mathfunc::sin\fR is resolved as described in
+\fBNAMESPACE RESOLUTION\fR in the \fBnamespace\fR(n) documentation.   Given the
+default value of \fBnamespace path\fR, \fB[namespace
+current]::tcl::mathfunc::sin\fR or \fB::tcl::mathfunc::sin\fR are the typical
+resolutions.
 .PP
-Some mathematical functions have several arguments, separated by commas like in C. Thus:
+As in C, a mathematical function may accept multiple arguments separated by commas. Thus,
 .PP
 .CS
 \fBexpr\fR {hypot($x,$y)}
 .CE
 .PP
-ends up as
+becomes
 .PP
 .CS
 tcl::mathfunc::hypot $x $y
 .CE
 .PP
-See the \fBmathfunc\fR(n) manual page for the math functions that are
+See the \fBmathfunc\fR(n) documentation for the math functions that are
 available by default.
 .SS "TYPES, OVERFLOW, AND PRECISION"
 .PP
-All internal computations involving integers are done calling on the
-LibTomMath multiple precision integer library as required so that all
-integer calculations are performed exactly.  Note that in Tcl releases
-prior to 8.5, integer calculations were performed with one of the C types
+When needed to guarantee exact performance, internal computations involving
+integers use the LibTomMath multiple precision integer library.  In Tcl releases
+prior to 8.5, integer calculations were performed using one of the C types
 \fIlong int\fR or \fITcl_WideInt\fR, causing implicit range truncation
 in those calculations where values overflowed the range of those types.
-Any code that relied on these implicit truncations will need to explicitly
-add \fBint()\fR or \fBwide()\fR function calls to expressions at the points
-where such truncation is required to take place.
+Any code that relied on these implicit truncations should instead call
+\fBint()\fR or \fBwide()\fR, which do truncate.
 .PP
-All internal computations involving floating-point are
-done with the C type \fIdouble\fR.
-When converting a string to floating-point, exponent overflow is
+Internal floating-point computations are
+performed using the \fIdouble\fR C type.
+When converting a string to floating-point value, exponent overflow is
 detected and results in the \fIdouble\fR value of \fBInf\fR or
 \fB\-Inf\fR as appropriate.  Floating-point overflow and underflow
 are detected to the degree supported by the hardware, which is generally
-pretty reliable.
+fairly reliable.
 .PP
-Conversion among internal representations for integer, floating-point,
-and string operands is done automatically as needed.
-For arithmetic computations, integers are used until some
-floating-point number is introduced, after which floating-point is used.
-For example,
+Conversion among internal representations for integer, floating-point, and
+string operands is done automatically as needed.  For arithmetic computations,
+integers are used until some floating-point number is introduced, after which
+floating-point values are used.  For example,
 .PP
 .CS
 \fBexpr\fR {5 / 4}
@@ -335,82 +312,62 @@ returns 1, while
 .CE
 .PP
 both return 1.25.
-Floating-point values are always returned with a
+A floating-point result can be distinguished from an integer result by the
+presence of either
 .QW \fB.\fR
-or an
+or
 .QW \fBe\fR
-so that they will not look like integer values.  For example,
+.PP
+. For example,
 .PP
 .CS
 \fBexpr\fR {20.0/5.0}
 .CE
 .PP
 returns \fB4.0\fR, not \fB4\fR.
-.SS "STRING OPERATIONS"
-.PP
-String values may be used as operands of the comparison operators,
-although the expression evaluator tries to do comparisons as integer
-or floating-point when it can,
-i.e., when all arguments to the operator allow numeric interpretations,
-except in the case of the \fBeq\fR and \fBne\fR operators.
-If one of the operands of a comparison is a string and the other
-has a numeric value, a canonical string representation of the numeric
-operand value is generated to compare with the string operand.
-Canonical string representation for integer values is a decimal string
-format.  Canonical string representation for floating-point values
-is that produced by the \fB%g\fR format specifier of Tcl's
-\fBformat\fR command.  For example, the commands
-.PP
-.CS
-\fBexpr\fR {"0x03" > "2"}
-\fBexpr\fR {"0y" > "0x12"}
-.CE
-.PP
-both return 1.  The first comparison is done using integer
-comparison, and the second is done using string comparison.
-Because of Tcl's tendency to treat values as numbers whenever
-possible, it is not generally a good idea to use operators like \fB==\fR
-when you really want string comparison and the values of the
-operands could be arbitrary;  it is better in these cases to use
-the \fBeq\fR or \fBne\fR operators, or the \fBstring\fR command instead.
 .SH "PERFORMANCE CONSIDERATIONS"
 .PP
-Enclose expressions in braces for the best speed and the smallest
-storage requirements.
-This allows the Tcl bytecode compiler to generate the best code.
-.PP
-As mentioned above, expressions are substituted twice:
-once by the Tcl parser and once by the \fBexpr\fR command.
-For example, the commands
+Where an expression contains syntax that Tcl would otherwise perform
+substitutions on, enclosing an expression in braces or otherwise quoting it
+so that it's a static value allows the Tcl compiler to generate bytecode for
+the expression, resulting in better speed and smaller storage requirements.
+This also avoids issues that can arise if Tcl is allowed to perform
+substitution on the value before \fBexpr\fR is called.
 .PP
+In the following example, the value of the expression is 11 because the Tcl parser first
+substitutes \fB$b\fR and \fBexpr\fR then substitutes \fB$a\fR.  Enclosing the
+expression in braces would result in a syntax error.
 .CS
 set a 3
 set b {$a + 2}
 \fBexpr\fR $b*4
 .CE
 .PP
-return 11, not a multiple of 4.
-This is because the Tcl parser will first substitute \fB$a + 2\fR for
-the variable \fBb\fR,
-then the \fBexpr\fR command will evaluate the expression \fB$a + 2*4\fR.
-.PP
-Most expressions do not require a second round of substitutions.
-Either they are enclosed in braces or, if not,
-their variable and command substitutions yield numbers or strings
-that do not themselves require substitutions.
-However, because a few unbraced expressions
-need two rounds of substitutions,
-the bytecode compiler must emit
-additional instructions to handle this situation.
-The most expensive code is required for
-unbraced expressions that contain command substitutions.
-These expressions must be implemented by generating new code
-each time the expression is executed.
-When the expression is unbraced to allow the substitution of a function or
-operator, consider using the commands documented in the \fBmathfunc\fR(n) or
-\fBmathop\fR(n) manual pages directly instead.
+
+When an expression is generated at runtime, like the one above is, the bytcode
+compiler must ensure that new code is generated each time the expression
+is evaluated.  This is the most costly kind of expression from a performance
+perspective.  In such cases, consider directly using the commands described in
+the \fBmathfunc\fR(n) or \fBmathop\fR(n) documentation instead of \fBexpr\fR.
+
+Most expressions are not formed at runtime, but are literal strings or contain
+substitutions that don't introduce other substitutions.  To allow the bytecode
+compiler to work with an expression as a string literal at compilation time,
+ensure that it contains no substitutions or that it is enclosed in braces or
+otherwise quoted to prevent Tcl from performing substitutions, allowing
+\fBexpr\fR to perform them instead.
 .SH EXAMPLES
 .PP
+A numeric comparison whose result is 1:
+.CS
+\fBexpr\fR {"0x03" > "2"}
+.CE
+.PP
+A string comparison whose result is 1:
+.CS
+\fBexpr\fR {"0y" > "0x12"}
+.CE
+.PP
 Define a procedure that computes an
 .QW interesting
 mathematical function:
@@ -444,8 +401,8 @@ each other:
 puts "a and b are [\fBexpr\fR {$a eq $b ? {equal} : {different}}]"
 .CE
 .PP
-Set a variable to whether an environment variable is both defined at
-all and also set to a true boolean value:
+Set a variable indicating whether an environment variable is defined and has
+value of true:
 .PP
 .CS
 set isTrue [\fBexpr\fR {
@@ -1,4 +1,4 @@
-'\" 
+'\"
 '\" Copyright (c) 1996 Sun Microsystems, Inc.
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
@@ -390,7 +390,7 @@ that use the third component do not attempt to perform tilde
 substitution.
 .RE
 .TP
-\fBfile stat  \fIname varName\fR
+\fBfile stat \fIname varName\fR
 .
 Invokes the \fBstat\fR kernel call on \fIname\fR, and uses the variable
 given by \fIvarName\fR to hold information returned from the kernel call.
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH flush n 7.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH foreach n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH gets n 7.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH history n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH if n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH incr n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -7,7 +7,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH info n 8.4 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -297,10 +297,11 @@ scripts are stored.
 This is actually the value of the \fBtcl_library\fR
 variable and may be changed by setting \fBtcl_library\fR.
 .TP
-\fBinfo loaded \fR?\fIinterp\fR?
+\fBinfo loaded \fR?\fIinterp\fR? \fR?\fIpackage\fR?
 .
-Returns a list describing all of the packages that have been loaded into
-\fIinterp\fR with the \fBload\fR command.
+Returns the filename loaded as part of \fIpackage\fR. If \fIpackage\fR
+is not specified, returns a list describing all of the packages
+that have been loaded into \fIinterp\fR with the \fBload\fR command.
 Each list element is a sub-list with two elements consisting of the
 name of the file from which the package was loaded and the name of
 the package.
@@ -5,7 +5,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH interp n 8.6 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH join n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -5,7 +5,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH lappend n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH lassign n 8.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -5,7 +5,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH list n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH load n 7.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH lrepeat n 8.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH lreverse n 8.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -303,7 +303,7 @@ used for qualified namespace or variable names.
 Sets or returns the unknown command handler for the current namespace.
 The handler is invoked when a command called from within the namespace
 cannot be found in the current namespace, the namespace's path nor in
-the global namespace. 
+the global namespace.
 The \fIscript\fR argument, if given, should be a well
 formed list representing a command name and optional arguments. When
 the handler is invoked, the full invocation line will be appended to the
@@ -138,7 +138,7 @@ before chaining from subclass, args = x 1 2 3 y
 in the superclass, args = a x 1 2 3 y b
 in the superclass, args = pureSynthesis
 after chaining from subclass
-before chaining from subclass, args = 
+before chaining from subclass, args =
 in the superclass, args = a b
 in the superclass, args = pureSynthesis
 after chaining from subclass
@@ -12,6 +12,7 @@
 package \- Facilities for package loading and version control
 .SH SYNOPSIS
 .nf
+\fBpackage files\fR \fIpackage\fR
 \fBpackage forget\fR ?\fIpackage package ...\fR?
 \fBpackage ifneeded \fIpackage version\fR ?\fIscript\fR?
 \fBpackage names\fR
@@ -43,6 +44,13 @@ primarily by system scripts that maintain the package database.
 The behavior of the \fBpackage\fR command is determined by its first argument.
 The following forms are permitted:
 .TP
+\fBpackage files\fR \fIpackage\fR
+.
+Lists all files forming part of \fIpackage\fR. Auto-loaded files are not
+included in this list, only files which were directly sourced during package
+initialization. The list order corresponds with the order in which the
+files were sourced.
+.TP
 \fBpackage forget\fR ?\fIpackage package ...\fR?
 .
 Removes all information about each specified package from this interpreter,
@@ -283,8 +291,8 @@ error.
 .PP
 When an interpreter is created, its initial selection mode value is set to
 .QW stable
-unless the environment variable \fBTCL_PKG_PREFER_LATEST\fR
-is set.  If that environment variable is defined (with any value) then
+unless the environment variable \fBTCL_PKG_PREFER_LATEST\fR is set
+(to any value) or the Tcl package itself is unstable. Otherwise
 the initial (and permanent) selection mode value is set to
 .QW latest .
 .RE
@@ -1,7 +1,7 @@
 '\"
 '\" Copyright (c) 1998-2000 by Scriptics Corporation.
 '\" All rights reserved.
-'\" 
+'\"
 .TH pkg::create n 8.3 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH pid n 7.0 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH "platform" n 1.0.4 platform "Tcl Bundled Packages"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH "platform::shell" n 1.1.4 platform::shell "Tcl Bundled Packages"
 .so man.macros
 .BS
@@ -3,7 +3,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH prefix n 8.6 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH puts n 7.5 Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -4,7 +4,7 @@
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
-'\" 
+'\"
 .TH pwd n "" Tcl "Tcl Built-In Commands"
 .so man.macros
 .BS
@@ -1,4 +1,4 @@
-'\" 
+'\"
 '\" Copyright (c) 2006 Andreas Kupries <andreas_kupries@users.sourceforge.net>
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
jan.nijtmans	f76c6ff3da	Merge trunk. Don't use ListObjLength() in tclStrToD.c	2017-02-03 14:53:27 +00:00
jan.nijtmans	19e0981d35	Split tclEmptyStringRep declaration over two lines. Otherwise gcc warning.	2017-02-03 14:29:50 +00:00
jan.nijtmans	596fd6687e	Merge trunk. Just keep some shortcuts, no longer guarantee that SetListFromAny() really returns a list type. Still experimental.	2017-02-03 14:28:17 +00:00
jan.nijtmans	b2a59d29b6	TIP #459 remaining part of implementation. Makes "package require Tk" give the right (... at least ... the expected ...) answer.	2017-02-03 12:27:37 +00:00
jan.nijtmans	d917353c7e	In TclGetNumberFromObj() macro (tclExecute.c): Don't fill in type if TCL_ERROR is returned: The caller doesn't do anything with this. Don't access (non-const) variable tclEmptyStringRep any more, use its value (&tclEmptyString) directly. Only keep it in tclPkg.c, for error checking.	2017-02-03 11:47:02 +00:00
jan.nijtmans	35ca781f6c	In stead of testing for tclEmptyStringRep, in many situations it is better to check whether the string ends with '\0'.	2017-02-02 15:50:49 +00:00
jan.nijtmans	28ac0c5353	Inpired by [pyk-emptystring] branch: Shortcuts/speedsup in number handling when dicts or lists are involved. Suppress generation of string rep in more situations.	2017-02-02 14:06:15 +00:00
jan.nijtmans	5fdbd4a749	Fix [d0f7ba56f0e8f93b7efb5b09ebc30a824bdd577a\|d0f7ba56f0]: INST_EQ first-argument NaN shortcut is too aggressive	2017-02-01 14:55:02 +00:00
jan.nijtmans	17cf9db2f7	Update documentation on recent changes in Tcl_LinkVar. Minor code clean-up. No functional changes.	2017-01-31 13:27:28 +00:00
ashok	4b357897d5	Added assoc, ftype and move as auto_execok shell built-ins on Windows.	2017-01-28 06:38:22 +00:00
jan.nijtmans	68275b03de	Some code cleanup: More internal use of size_t, less type casts (because of this). No functional changes.	2017-01-27 14:31:12 +00:00
jan.nijtmans	2645c0ef3a	If TCL_NO_DEPRECATED is defined, remove the "case" statement, and use much less interp->result. Implementation mostly taken over from "novem". If TCL_NO_DEPRECATED is not defined, nothing changes.	2017-01-25 12:22:16 +00:00
jan.nijtmans	7de961e9fa	Merge trunk	2017-01-23 09:11:34 +00:00
jan.nijtmans	c26df8ae12	Fix [39f6304c2e90549c209cd11a7920dc9921b9f48e\|39f6304c2e] follow-up: Make Tcl_LinkVar toleranto to the empty string as well	2017-01-20 16:21:43 +00:00
fvogel	47692f4e99	Fix [1f4bb8162f]: lsort -dictionary documentation to be improved	2017-01-19 22:38:40 +00:00
jan.nijtmans	e7e764dbdf	Implement tag "deprecated" in genStubs.tcl. Will be used in Tk 8.7, for tagging the deprecated function Tk_FreeXId()	2017-01-17 12:02:43 +00:00
jan.nijtmans	b0aa1e2416	merge core-8-6-branch	2017-01-17 10:04:42 +00:00
jan.nijtmans	3dba96d22a	Fix for missing proper initialization of the threaded allocator in some situations. Problem reported by Zoran Vasiljevic, only noted when building/running NaviServer/AOLServer with Tcl 8.7 (trunk).	2017-01-16 11:57:17 +00:00
jan.nijtmans	a0ea496ffb	Update zlib to version 1.2.11	2017-01-16 11:53:07 +00:00
venkat	893b999f51	Merge IETF tzdata2016j	2017-01-14 08:47:15 +00:00
jan.nijtmans	35d8e3912d	Introduce new function TclInitThreadAlloc(), symmetric with TclFinalizeThreadAlloc()	2017-01-13 14:43:07 +00:00
jan.nijtmans	a89608d308	Merge-mark (restoring the expected merge order from core-8-5-branch -> core-8-6-branch -> trunk -> novem)	2017-01-13 13:02:32 +00:00
sebres	bd9426f3e5	missing rules.vc after merge	2017-01-13 12:57:45 +00:00
jan.nijtmans	abdbe053ea	Enhance nmakehlp, allowing multiple arguments for "-l", and recognizing a new linker code LNK4224. Patch by sebres.	2017-01-13 12:20:21 +00:00
jan.nijtmans	6ecb7aeabf	Patch from Zoran Vasiljevic, fix for missing proper initialization of the threaded allocator in some situations.	2017-01-13 11:17:17 +00:00
jan.nijtmans	d42b3a00d3	Merge core-8-6-branch	2017-01-12 10:34:05 +00:00
jan.nijtmans	1ebb964dbc	Use more Tcl_AppendResult(), in order to prevent the use of a (char *) type case.	2017-01-11 16:23:18 +00:00
jan.nijtmans	e6d3efd5e1	Merge core-8-6-branch. Do gcc-compiles with the option -Wwrite-strings, so we can detect mis-usage of "const". Make Tcl_AddErrorInfo() and Tcl_AddObjErrorInfo() a macro.	2017-01-11 14:10:33 +00:00
sebres	ec306bb22e	Merge fix clock test-cases from 8.6: Make test clock-67.5 time zone independent - execution fails in the time zones below gmt	2017-01-09 18:28:56 +00:00
sebres	8b67c7f038	Merge bug_b87ad7e914	2017-01-09 17:53:00 +00:00
jan.nijtmans	cc89e55f7d	Merge trunk	2017-01-06 11:39:10 +00:00
jan.nijtmans	860e480e47	Complete the upgrade to Zlib 1.2.10: Now add the .lib and .dll files	2017-01-06 10:30:31 +00:00
jan.nijtmans	03d119a937	Make TclGetLoadedPackagesEx() work with other than the only current interpreter (didn't really think about that earlier ... ). Actually slightly more correct.	2017-01-05 15:13:58 +00:00
jan.nijtmans	3703dbd940	Merge trunk	2017-01-05 14:47:07 +00:00
jan.nijtmans	570a13bc17	Fix [7c7d3b4481d4e4e86420b54031f4abd1df18d64\|7c7d3b4481]: load test failures. There's a difference between "" and NULL as interpreter name.	2017-01-05 14:27:20 +00:00
jan.nijtmans	8da19e064b	One more ::tcl::Pkg::source, for the Mac	2017-01-05 13:09:26 +00:00
jan.nijtmans	666afa7352	Merge trunk. Improve test-case. Bring back "source -nopkg", but only as undocumented internal helper for ::tcl::Pkg::source.	2017-01-05 11:55:56 +00:00
fvogel	45db025684	Added more glob patterns in order to ignore html generated documentation and Windows-specific compilation products when running fossil extra	2017-01-04 16:34:03 +00:00
jan.nijtmans	5e02396d5e	In stead of "source -nopkg" use a ::tcl::Pkg::source utility function.	2017-01-04 16:23:23 +00:00
jan.nijtmans	2e108cd831	Fix safe.tcl test-cases: "source -nopkg" is not necessary here: "source" is an alias for "::safe::AliasSource", which doesn't use "source"	2017-01-04 15:16:31 +00:00
jan.nijtmans	27fb8875b7	Merge trunk. First steps in eliminating "source -nopkg". Some test-cases still fail.	2017-01-04 14:05:20 +00:00
jan.nijtmans	acdb5b2026	Fix 2 test-cases, due to changed command options.	2017-01-04 13:51:26 +00:00
jan.nijtmans	f711652d04	TIP [http://www.tcl.tk/cgi-bin/tct/tip/459 \|459] implementation, but (for now) without the "source -nopkg" part.	2017-01-04 13:38:56 +00:00
jan.nijtmans	ca2077254b	TIP [http://www.tcl.tk/cgi-bin/tct/tip/456 \|456] implementation: Extend the C API to Support Passing Options to TCP Server Creation	2017-01-04 12:55:27 +00:00
jan.nijtmans	99fa27bc91	merge core-8-6-branch	2017-01-04 11:55:28 +00:00
limeboy	a2c66d61f0	Make the code slightly more pleasing to the eyes.	2017-01-01 22:19:26 +00:00
jan.nijtmans	aba0a7a6cd	Make options -reuseaddr/-reuseport forbidden without -server, no matter the value being true or false. Some additional test-cases.	2016-12-20 12:35:33 +00:00
jan.nijtmans	d97bb854b0	merge fork	2016-12-20 11:47:11 +00:00
limeboy	f208386ff7	Decouple the switch handling.	2016-12-20 10:56:53 +00:00
limeboy	e574cfbc71	Correct the handling of -server and its options.	2016-12-20 10:22:22 +00:00
jan.nijtmans	7a1d9d5758	merge trunk (still has test failure in socket.test)	2016-12-20 09:30:02 +00:00
limeboy	dfbc8a6296	Update the documentation	2016-12-14 16:03:53 +00:00
limeboy	cbe4a7dae5	Adjust OpenTcpServer for the latest changes to OpenTcpServerEx	2016-12-14 15:59:43 +00:00
limeboy	caf8932e2e	Fix for the argument parsing phase in the [socket] command.	2016-12-14 15:52:21 +00:00
limeboy	2e467a4c9a	Make OpenTcpServerEx accept a 'service' string parameter instead of a port.	2016-12-14 15:49:27 +00:00
jan.nijtmans	3df1a90364	Bring back stub table in original state. Merge trunk	2016-12-08 17:52:36 +00:00
limeboy	13a4d32330	merge trunk	2016-12-01 12:01:01 +00:00
jan.nijtmans	804199d4b7	Implement the "package forget" part, which was still missing. Handle the case that a filename contains spaces.	2016-11-29 09:45:20 +00:00
jan.nijtmans	1df184e860	slightly simpler	2016-11-28 15:29:36 +00:00
jan.nijtmans	b7e862c565	Complete implementation, tests and documentation	2016-11-28 13:17:47 +00:00
jan.nijtmans	ee6806b80d	Add "package files" testcase, which doesn give the right answer. So still work to do	2016-11-26 17:47:27 +00:00
jan.nijtmans	ecda933dfc	Merge trunk. Implementation looks complete. Still missing: test-cases and documentation.	2016-11-25 15:06:13 +00:00
limeboy	8fe50e3f91	Windows support and minor touchups to the documentation.	2016-11-25 14:53:20 +00:00
limeboy	3d5c28f527	Minor documentation touchups.	2016-11-25 13:27:56 +00:00
jan.nijtmans	7a6b829025	Merge trunk, and fix two socket test-cases.	2016-11-25 09:38:04 +00:00
limeboy	e123cfc452	Forgot a - in the parameters array.	2016-11-24 21:15:15 +00:00
limeboy	467b6eeb8e	Allow a boolean argument to be passed.	2016-11-24 21:01:43 +00:00
jan.nijtmans	43f0f22700	merge trunk	2016-11-24 20:55:43 +00:00
limeboy	07020d6350	First round of documentation update.	2016-11-24 20:28:42 +00:00
jan.nijtmans	2cbc2f1993	merge fork	2016-11-24 16:21:20 +00:00
jan.nijtmans	1b0d436cc7	Starting implementing the "package files" command. TIP still to be written.	2016-11-24 16:20:05 +00:00
limeboy	15b2687d3c	Adjust the tests and add a handful of new ones.	2016-11-24 15:00:36 +00:00
jan.nijtmans	842d6d00f1	Fix compile error if SO_REUSEPORT not supported. Put command options in alphabetical order	2016-11-24 13:18:10 +00:00
limeboy	1859293255	Implement the whole TIP 456 specification. Also introduces the `-reuseaddr' and `-reuseport' options for the `socket' command.	2016-11-24 12:47:21 +00:00
jan.nijtmans	32f810fc3b	Fix indenting	2016-11-22 11:24:48 +00:00
jan.nijtmans	6989a199e7	Added stub entry for tip #456 . Documentation and tests still missing. Doesn't conform to TIP yet.	2016-11-22 11:21:00 +00:00
jan.nijtmans	ee70b22d59	This is patch.002 from ticket [0b9d3ba2ba3e1e3fc33c97d5a9fa7ef85d11a696\|0b9d3ba2ba], as first start of tip-456 implementation	2016-11-22 10:06:18 +00:00