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-revision 122 by ph10,
Mon Mar 12 15:10:25 2007 UTC
+revision 230 by ph10,
Mon Sep 10 13:23:56 2007 UTC
 Line 1
  ChangeLog for PCRE
  ------------------
- Version 7.1 12-Mar-07
+ Version 7.4 10-Sep-07
+ ---------------------
+.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
+     means that a class such as [\s] counted as "explicit reference to CR or
+     LF". That isn't really right - the whole point of the change was to try to
+     help when there was an actual mention of one of the two characters. So now
+     the change happens only if \r or \n (or a literal CR or LF) character is
+     encountered.
+.  The 32-bit options word was also used for 6 internal flags, but the numbers
+     of both had grown to the point where there were only 3 bits left.
+     Fortunately, there was spare space in the data structure, and so I have
+     moved the internal flags into a new 16-bit field to free up more option
+     bits.
+.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
+     but did not set the internal JCHANGED flag - either of these is enough to
+     control the way the "get" function works - but the PCRE_INFO_JCHANGED
+     facility is supposed to tell if (?J) was ever used, so now (?J) at the
+     start sets both bits.
+ Version 7.3 28-Aug-07
+ ---------------------
+. In the rejigging of the build system that eventually resulted in 7.1, the
+     line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
+     brackets there is not right, since it causes compilers to look for an
+     installed pcre.h, not the version that is in the source that is being
+     compiled (which of course may be different). I have changed it back to:
+       #include "pcre.h"
+     I have a vague recollection that the change was concerned with compiling in
+     different directories, but in the new build system, that is taken care of
+     by the VPATH setting the Makefile.
+. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
+     when the subject happened to end in the byte 0x85 (e.g. if the last
+     character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
+     characters but of course it shouldn't be taken as a newline when it is part
+     of another character. The bug was that, for an unlimited repeat of . in
+     not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
+     characters when looking for a newline.
+. A small performance improvement in the DOTALL UTF-8 mode .* case.
+. Debugging: adjusted the names of opcodes for different kinds of parentheses
+     in debug output.
+. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
+     long printing in the pcrecpp unittest when running under MinGW.
+. ESC_K was left out of the EBCDIC table.
+. Change 7.0/38 introduced a new limit on the number of nested non-capturing
+     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
+     limit also applies to "virtual nesting" when a pattern is recursive, and in
+     this case 1000 isn't so big. I have been able to remove this limit at the
+     expense of backing off one optimization in certain circumstances. Normally,
+     when pcre_exec() would call its internal match() function recursively and
+     immediately return the result unconditionally, it uses a "tail recursion"
+     feature to save stack. However, when a subpattern that can match an empty
+     string has an unlimited repetition quantifier, it no longer makes this
+     optimization. That gives it a stack frame in which to save the data for
+     checking that an empty string has been matched. Previously this was taken
+     from the 1000-entry workspace that had been reserved. So now there is no
+     explicit limit, but more stack is used.
+. Applied Daniel's patches to solve problems with the import/export magic
+     syntax that is required for Windows, and which was going wrong for the
+     pcreposix and pcrecpp parts of the library. These were overlooked when this
+     problem was solved for the main library.
+. There were some crude static tests to avoid integer overflow when computing
+     the size of patterns that contain repeated groups with explicit upper
+     limits. As the maximum quantifier is 65535, the maximum group length was
+     set at 30,000 so that the product of these two numbers did not overflow a
+-bit integer. However, it turns out that people want to use groups that
+     are longer than 30,000 bytes (though not repeat them that many times).
+     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
+     made it possible to implement the integer overflow checks in a much more
+     dynamic way, which I have now done. The artificial limitation on group
+     length has been removed - we now have only the limit on the total length of
+     the compiled pattern, which depends on the LINK_SIZE setting.
+. Fixed a bug in the documentation for get/copy named substring when
+     duplicate names are permitted. If none of the named substrings are set, the
+     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
+     empty string.
+. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
+     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
+     because the ] is interpreted as the first data character and the
+     terminating ] is not found. PCRE has been made compatible with Perl in this
+     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
+     cause memory overwriting.
+. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
+     string has been matched (to stop an infinite loop). It was not recognizing
+     a conditional subpattern that could match an empty string if that
+     subpattern was within another subpattern. For example, it looped when
+     trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
+     condition was not nested. This bug has been fixed.
+. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
+     past the start of the subject in the presence of bytes with the top bit
+     set, for example "\x8aBCD".
+. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
+     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
+. Optimized (?!) to (*FAIL).
+. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
+     This restricts code points to be within the range 0 to 0x10FFFF, excluding
+     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
+     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
+     does: it's just the validity check that is more restrictive.
+. Inserted checks for integer overflows during escape sequence (backslash)
+     processing, and also fixed erroneous offset values for syntax errors during
+     backslash processing.
+. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
+     for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
+. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
+     caused an overrun.
+. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
+     something other than just ASCII characters) inside a group that had an
+     unlimited repeat caused a loop at compile time (while checking to see
+     whether the group could match an empty string).
+. Debugging a pattern containing \p or \P could cause a crash. For example,
+     [\P{Any}] did so. (Error in the code for printing property names.)
+. An orphan \E inside a character class could cause a crash.
+. A repeated capturing bracket such as (A)? could cause a wild memory
+     reference during compilation.
+. There are several functions in pcre_compile() that scan along a compiled
+     expression for various reasons (e.g. to see if it's fixed length for look
+     behind). There were bugs in these functions when a repeated \p or \P was
+     present in the pattern. These operators have additional parameters compared
+     with \d, etc, and these were not being taken into account when moving along
+     the compiled data. Specifically:
+     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
+         length.
+     (b) An item such as \pL+ within a repeated group could cause crashes or
+         loops.
+     (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
+         "reference to non-existent subpattern" error.
+     (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
+. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
+     characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
+. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
+. Patterns such as [\P{Yi}A] which include \p or \P and just one other
+     character were causing crashes (broken optimization).
+. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
+     \p or \P) caused a compile-time loop.
+. More problems have arisen in unanchored patterns when CRLF is a valid line
+     break. For example, the unstudied pattern [\r\n]A does not match the string
+     "\r\nA" because change 7.0/46 below moves the current point on by two
+     characters after failing to match at the start. However, the pattern \nA
+     *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
+     the same is true. There doesn't seem any very clean way out of this, but
+     what I have chosen to do makes the common cases work: PCRE now takes note
+     of whether there can be an explicit match for \r or \n anywhere in the
+     pattern, and if so, 7.0/46 no longer applies. As part of this change,
+     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
+     pattern has explicit CR or LF references.
+. Added (*CR) etc for changing newline setting at start of pattern.
+ Version 7.2 19-Jun-07
+ ---------------------
+. If the fr_FR locale cannot be found for test 3, try the "french" locale,
+     which is apparently normally available under Windows.
+. Re-jig the pcregrep tests with different newline settings in an attempt
+     to make them independent of the local environment's newline setting.
+. Add code to configure.ac to remove -g from the CFLAGS default settings.
+. Some of the "internals" tests were previously cut out when the link size
+     was not 2, because the output contained actual offsets. The recent new
+     "Z" feature of pcretest means that these can be cut out, making the tests
+     usable with all link sizes.
+. Implemented Stan Switzer's goto replacement for longjmp() when not using
+     stack recursion. This gives a massive performance boost under BSD, but just
+     a small improvement under Linux. However, it saves one field in the frame
+     in all cases.
+. Added more features from the forthcoming Perl 5.10:
+     (a) (?-n) (where n is a string of digits) is a relative subroutine or
+         recursion call. It refers to the nth most recently opened parentheses.
+     (b) (?+n) is also a relative subroutine call; it refers to the nth next
+         to be opened parentheses.
+     (c) Conditions that refer to capturing parentheses can be specified
+         relatively, for example, (?(-2)... or (?(+3)...
+     (d) \K resets the start of the current match so that everything before
+         is not part of it.
+     (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
+     (f) \g{name} is another synonym - part of Perl 5.10's unification of
+         reference syntax.
+     (g) (?| introduces a group in which the numbering of parentheses in each
+         alternative starts with the same number.
+     (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
+. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
+     PCRE_INFO_JCHANGED.
+. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
+     terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
+     for detecting groups that can match an empty string.
+. A pattern with a very large number of alternatives (more than several
+     hundred) was running out of internal workspace during the pre-compile
+     phase, where pcre_compile() figures out how much memory will be needed. A
+     bit of new cunning has reduced the workspace needed for groups with
+     alternatives. The 1000-alternative test pattern now uses 12 bytes of
+     workspace instead of running out of the 4096 that are available.
+. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
+. Applied patch from Google to remove an optimization that didn't quite work.
+     The report of the bug said:
+       pcrecpp::RE("a*").FullMatch("aaa") matches, while
+       pcrecpp::RE("a*?").FullMatch("aaa") does not, and
+       pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
+. If \p or \P was used in non-UTF-8 mode on a character greater than 127
+     it matched the wrong number of bytes.
+ Version 7.1 24-Apr-07
  ---------------------
 . Applied Bob Rossi and Daniel G's patches to convert the build system to one
-Line 26 
 Version 7.1 12-Mar-07
+Line 286 
 Version 7.1 12-Mar-07
      .br or .in.
 . Updated comments in configure.ac that get placed in config.h.in and also
      arranged for config.h to be included in the distribution, with the name
      config.h.generic, for the benefit of those who have to compile without
      Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
 . Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
-     makevp.bat for the current PCRE, using the additional files !compile.txt,
+     makevp.bat for the current PCRE, using the additional files
-     !linklib.txt, and pcregexp.pas.
+     makevp_c.txt, makevp_l.txt, and pcregexp.pas.
 . A Windows user reported a minor discrepancy with test 2, which turned out
      to be caused by a trailing space on an input line that had got lost in his
-Line 63 
 Version 7.1 12-Mar-07
+Line 323 
 Version 7.1 12-Mar-07
 . Fixed two bugs in the emulated memmove() function in pcre_internal.h:
      (a) It was defining its arguments as char * instead of void *.
      (b) It was assuming that all moves were upwards in memory; this was true
          a long time ago when I wrote it, but is no longer the case.
      The emulated memove() is provided for those environments that have neither
      memmove() nor bcopy(). I didn't think anyone used it these days, but that
      is clearly not the case, as these two bugs were recently reported.
 . The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
      and Detrail to create the HTML documentation, the .txt form of the man
      pages, and it removes trailing spaces from listed files. It also creates
      pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
      case, it wraps all the #defines with #ifndefs. This script should be run
      before "make dist".
 . Fixed two fairly obscure bugs concerned with quantified caseless matching
      with Unicode property support.
      (a) For a maximizing quantifier, if the two different cases of the
          character were of different lengths in their UTF-8 codings (there are
          some cases like this - I found 11), and the matching function had to
          back up over a mixture of the two cases, it incorrectly assumed they
          were both the same length.
      (b) When PCRE was configured to use the heap rather than the stack for
          recursion during matching, it was not correctly preserving the data for
          the other case of a UTF-8 character when checking ahead for a match
          while processing a minimizing repeat. If the check also involved
          matching a wide character, but failed, corruption could cause an
          erroneous result when trying to check for a repeat of the original
          character.
 . Some tidying changes to the testing mechanism:
      (a) The RunTest script now detects the internal link size and whether there
          is UTF-8 and UCP support by running ./pcretest -C instead of relying on
          values substituted by "configure". (The RunGrepTest script already did
          this for UTF-8.) The configure.ac script no longer substitutes the
          relevant variables.
      (b) The debugging options /B and /D in pcretest show the compiled bytecode
          with length and offset values. This means that the output is different
          for different internal link sizes. Test 2 is skipped for link sizes
          other than 2 because of this, bypassing the problem. Unfortunately,
          there was also a test in test 3 (the locale tests) that used /B and
          failed for link sizes other than 2. Rather than cut the whole test out,
          I have added a new /Z option to pcretest that replaces the length and
          offset values with spaces. This is now used to make test 3 independent
          of link size. (Test 2 will be tidied up later.)
 . If erroroffset was passed as NULL to pcre_compile, it provoked a
      segmentation fault instead of returning the appropriate error message.
+. In multiline mode when the newline sequence was set to "any", the pattern
+     ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
+     This doesn't seem right; it now treats the CRLF combination as the line
+     ending, and so does not match in that case. It's only a pattern such as ^$
+     that would hit this one: something like ^ABC$ would have failed after \r
+     and then tried again after \r\n.
+. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
+     in an attempt to make files that differ only in their line terminators
+     compare equal. This works on Linux.
+. Under certain error circumstances pcregrep might try to free random memory
+     as it exited. This is now fixed, thanks to valgrind.
+. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
+     "abc\r\n\r\n", it found an unwanted second match after the second \r. This
+     was because its rules for how to advance for /g after matching an empty
+     string at the end of a line did not allow for this case. They now check for
+     it specially.
+. pcretest is supposed to handle patterns and data of any length, by
+     extending its buffers when necessary. It was getting this wrong when the
+     buffer for a data line had to be extended.
+. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
+     CRLF as a newline sequence.
+. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
+     out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
+     I have nevertheless tidied it up.
+. Added some casts to kill warnings from HP-UX ia64 compiler.
+. Added a man page for pcre-config.
  Version 7.0 19-Dec-06
  ---------------------

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