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-revision 691 by ph10,
Sun Sep 11 14:31:21 2011 UTC
+revision 937 by ph10,
Sun Feb 26 15:58:56 2012 UTC
 Line 1
  ChangeLog for PCRE
  ------------------
- Version 8.20 12-Sep-2011
+ Version 8.31
+ -----------------------------
+.  Fixing a wrong JIT test case and some compiler warnings.
+.  Removed a bashism from the RunTest script.
+.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
+     to unsigned type, result still unsigned" that was given by an MS compiler
+     on encountering the code "-sizeof(xxx)".
+.  Partial matching support is added to the JIT compiler.
+.  Fixed several bugs concerned with partial matching of items that consist
+     of more than one character:
+     (a) /^(..)\1/ did not partially match "aba" because checking references was
+         done on an "all or nothing" basis. This also applied to repeated
+         references.
+     (b) \R did not give a hard partial match if \r was found at the end of the
+         subject.
+     (c) \X did not give a hard partial match after matching one or more
+         characters at the end of the subject.
+     (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
+         a partial match for the string "\r".
+     (e) When newline was set to CRLF, the metacharacter "." did not recognize
+         a partial match for a CR character at the end of the subject string.
+.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
+     running pcretest, the text "(JIT)" added to the output whenever JIT is
+     actually used to run the match.
+.  Individual JIT compile options can be set in pcretest by following -s+[+]
+     or /S+[+] with a digit between 1 and 7.
+.  OP_NOT now supports any UTF character not just single-byte ones.
+.  (*MARK) control verb is now supported by the JIT compiler.
+. The command "./RunTest list" lists the available tests without actually
+     running any of them. (Because I keep forgetting what they all are.)
+. Add PCRE_INFO_MAXLOOKBEHIND.
+. Applied a (slightly modified) user-supplied patch that improves performance
+     when the heap is used for recursion (compiled with --disable-stack-for-
+     recursion). Instead of malloc and free for each heap frame each time a
+     logical recursion happens, frames are retained on a chain and re-used where
+     possible. This sometimes gives as much as 30% improvement.
+. As documented, (*COMMIT) is now confined to within a recursive subpattern
+     call.
+. As documented, (*COMMIT) is now confined to within a positive assertion.
+. It is now possible to link pcretest with libedit as an alternative to
+     libreadline.
+ Version 8.30 04-February-2012
+ -----------------------------
+.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
+     name is defined in ctype.h.
+.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
+     only in quite long subpatterns.
+.  Removed the function pcre_info(), which has been obsolete and deprecated
+     since it was replaced by pcre_fullinfo() in February 2000.
+.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
+     match a (*MARK), and the match failed at the start of the subject, a
+     reference to memory before the start of the subject could occur. This bug
+     was introduced by fix 17 of release 8.21.
+.  A reference to an unset group with zero minimum repetition was giving
+     totally wrong answers (in non-JavaScript-compatibility mode). For example,
+     /(another)?(\1?)test/ matched against "hello world test". This bug was
+     introduced in release 8.13.
+.  Add support for 16-bit character strings (a large amount of work involving
+     many changes and refactorings).
+.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
+     command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
+     from a file.
+.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
+     rounding is not applied in this particular case).
+.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
+     if they appear, or are escaped, in patterns.
+. Get rid of a number of -Wunused-but-set-variable warnings.
+. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
+     "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
+     Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
+     also returns the mark "x". This bug applied to capturing parentheses,
+     non-capturing parentheses, and atomic parentheses. It also applied to some
+     assertions.
+. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
+     information out of configure.ac instead of relying on pcre.h.generic, which
+     is not stored in the repository.
+. Applied Dmitry V. Levin's patch for a more portable method for linking with
+     -lreadline.
+. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
+. Applied Graycode's patch to put the top-level frame on the stack rather
+     than the heap when not using the stack for recursion. This gives a
+     performance improvement in many cases when recursion is not deep.
+. Experimental code added to "pcretest -C" to output the stack frame size.
+ Version 8.21 12-Dec-2011
  ------------------------
-. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
+.  Updating the JIT compiler.
-    a POSIX class. After further experiments with Perl, which convinced me that
-    Perl has bugs and confusions, a closing square bracket is no longer allowed
+.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
-    in a POSIX name. This bug also affected patterns with classes that started
+     are added as well.
-    with full stops.
+.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
-. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
+     PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
-    substring, but while checking the failing first alternative, substring 1 is
+     calling _pcre_jit_exec. Some extra comments are added.
-    temporarily captured. If the output vector supplied to pcre_exec() was not
-    big enough for this capture, the yield of the function was still zero
+.  (*MARK) settings inside atomic groups that do not contain any capturing
-    ("insufficient space for captured substrings"). This cannot be totally fixed
+     parentheses, for example, (?>a(*:m)), were not being passed out. This bug
-    without adding another stack variable, which seems a lot of expense for a
+     was introduced by change 18 for 8.20.
-    edge case. However, I have improved the situation in cases such as
-    /(a)(b)x|abc/ matched against "abc", where the return code indicates that
+.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
-    fewer than the maximum number of slots in the ovector have been set.
+     ECMA-262 standard.
-. Related to (2) above: when there are more back references in a pattern than
+.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
-    slots in the output vector, pcre_exec() uses temporary memory during
+     erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
-    matching, and copies in the captures as far as possible afterwards. It was
+     This bug was probably introduced by change 9 of 8.13.
-    using the entire output vector, but this conflicts with the specification
-    that only 2/3 is used for passing back captured substrings. Now it uses only
+.  While fixing 6 above, I noticed that a number of other items were being
-    the first 2/3, for compatibility. This is, of course, another edge case.
+     incorrectly rejected as "not fixed length". This arose partly because newer
+     opcodes had not been added to the fixed-length checking code. I have (a)
-. Zoltan Herczeg's just-in-time compiler support has been integrated into the
+     corrected the bug and added tests for these items, and (b) arranged for an
-    main code base, and can be used by building with --enable-jit. When this is
+     error to occur if an unknown opcode is encountered while checking for fixed
-    done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
+     length instead of just assuming "not fixed length". The items that were
-    runtime --no-jit option is given.
+     rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
+     (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
-. When the number of matches in a pcre_dfa_exec() run exactly filled the
+     repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
-    ovector, the return from the function was zero, implying that there were
-    other matches that did not fit. The correct "exactly full" value is now
+.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
-    returned.
+     being incorrectly compiled and would have given unpredicatble results.
-. If a subpattern that was called recursively or as a subroutine contained
+.  A possessively repeated subpattern with minimum repeat count greater than
-    (*PRUNE) or any other control that caused it to give a non-standard return,
+     one behaved incorrectly. For example, (A){2,}+ behaved as if it was
-    invalid errors such as "Error -26 (nested recursion at the same subject
+     (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
-    position)" or even infinite loops could occur.
+     the first (A) could occur when it should not.
+. Add a cast and remove a redundant test from the code.
+. JIT should use pcre_malloc/pcre_free for allocation.
+. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
+     best practice nowadays, and helps with cross-compiling. (If the exec_prefix
+     is anything other than /usr, -L is still shown).
+. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
+. Perl does not support \N without a following name in a [] class; PCRE now
+     also gives an error.
+. If a forward reference was repeated with an upper limit of around 2000,
+     it caused the error "internal error: overran compiling workspace". The
+     maximum number of forward references (including repeats) was limited by the
+     internal workspace, and dependent on the LINK_SIZE. The code has been
+     rewritten so that the workspace expands (via pcre_malloc) if necessary, and
+     the default depends on LINK_SIZE. There is a new upper limit (for safety)
+     of around 200,000 forward references. While doing this, I also speeded up
+     the filling in of repeated forward references.
+. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
+     incorrectly expecting the subject to contain another "a" after the start.
+. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
+     in the match, the SKIP should be ignored. This was not happening; instead
+     the SKIP was being treated as NOMATCH. For patterns such as
+     /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
+     tested.
+. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
+     now much more compatible with Perl, in particular in cases where the result
+     is a non-match for a non-anchored pattern. For example, if
+     /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
+     "m", where previously it did not return a name. A side effect of this
+     change is that for partial matches, the last encountered mark name is
+     returned, as for non matches. A number of tests that were previously not
+     Perl-compatible have been moved into the Perl-compatible test files. The
+     refactoring has had the pleasing side effect of removing one argument from
+     the match() function, thus reducing its stack requirements.
+. If the /S+ option was used in pcretest to study a pattern using JIT,
+     subsequent uses of /S (without +) incorrectly behaved like /S+.
+. Retrieve executable code size support for the JIT compiler and fixing
+     some warnings.
+. A caseless match of a UTF-8 character whose other case uses fewer bytes did
+     not work when the shorter character appeared right at the end of the
+     subject string.
+. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
+     systems.
+. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
+     output it when the /M option is used in pcretest.
+. The CheckMan script was not being included in the distribution. Also, added
+     an explicit "perl" to run Perl scripts from the PrepareRelease script
+     because this is reportedly needed in Windows.
+. If study data was being save in a file and studying had not found a set of
+     "starts with" bytes for the pattern, the data written to the file (though
+     never used) was taken from uninitialized memory and so caused valgrind to
+     complain.
+. Updated RunTest.bat as provided by Sheri Pierce.
+. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
+. Computation of memory usage for the table of capturing group names was
+     giving an unnecessarily large value.
+ Version 8.20 21-Oct-2011
+ ------------------------
+.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
+     a POSIX class. After further experiments with Perl, which convinced me that
+     Perl has bugs and confusions, a closing square bracket is no longer allowed
+     in a POSIX name. This bug also affected patterns with classes that started
+     with full stops.
+.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
+     captured substring, but while checking the failing first alternative,
+     substring 1 is temporarily captured. If the output vector supplied to
+     pcre_exec() was not big enough for this capture, the yield of the function
+     was still zero ("insufficient space for captured substrings"). This cannot
+     be totally fixed without adding another stack variable, which seems a lot
+     of expense for a edge case. However, I have improved the situation in cases
+     such as /(a)(b)x|abc/ matched against "abc", where the return code
+     indicates that fewer than the maximum number of slots in the ovector have
+     been set.
+.  Related to (2) above: when there are more back references in a pattern than
+     slots in the output vector, pcre_exec() uses temporary memory during
+     matching, and copies in the captures as far as possible afterwards. It was
+     using the entire output vector, but this conflicts with the specification
+     that only 2/3 is used for passing back captured substrings. Now it uses
+     only the first 2/3, for compatibility. This is, of course, another edge
+     case.
+.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
+     main code base, and can be used by building with --enable-jit. When this is
+     done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
+     runtime --no-jit option is given.
+.  When the number of matches in a pcre_dfa_exec() run exactly filled the
+     ovector, the return from the function was zero, implying that there were
+     other matches that did not fit. The correct "exactly full" value is now
+     returned.
+.  If a subpattern that was called recursively or as a subroutine contained
+     (*PRUNE) or any other control that caused it to give a non-standard return,
+     invalid errors such as "Error -26 (nested recursion at the same subject
+     position)" or even infinite loops could occur.
+.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
+     computing the minimum length on reaching *ACCEPT, and so ended up with the
+     wrong value of 1 rather than 0. Further investigation indicates that
+     computing a minimum subject length in the presence of *ACCEPT is difficult
+     (think back references, subroutine calls), and so I have changed the code
+     so that no minimum is registered for a pattern that contains *ACCEPT.
+.  If (*THEN) was present in the first (true) branch of a conditional group,
+     it was not handled as intended. [But see 16 below.]
+.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
+     Sheri Pierce.
+. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
+     the first byte in a match must be "a".
+. Change 17 for 8.13 increased the recursion depth for patterns like
+     /a(?:.)*?a/ drastically. I've improved things by remembering whether a
+     pattern contains any instances of (*THEN). If it does not, the old
+     optimizations are restored. It would be nice to do this on a per-group
+     basis, but at the moment that is not feasible.
+. In some environments, the output of pcretest -C is CRLF terminated. This
+     broke RunTest's code that checks for the link size. A single white space
+     character after the value is now allowed for.
+. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
+     For "fr", it uses the Windows-specific input and output files.
+. If (*THEN) appeared in a group that was called recursively or as a
+     subroutine, it did not work as intended. [But see next item.]
+. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
+     pattern fragments (but not containing any | characters). If A and B are
+     matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
+     was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
+     D. In other words, Perl considers parentheses that do not contain any |
+     characters to be part of a surrounding alternative, whereas PCRE was
+     treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
+     differently. PCRE now behaves in the same way as Perl, except in the case
+     of subroutine/recursion calls such as (?1) which have in any case always
+     been different (but PCRE had them first :-).
+. Related to 15 above: Perl does not treat the | in a conditional group as
+     creating alternatives. Such a group is treated in the same way as an
+     ordinary group without any | characters when processing (*THEN). PCRE has
+     been changed to match Perl's behaviour.
+. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
+     RunGrepTest script failed.
+. Change 22 for version 13 caused atomic groups to use more stack. This is
+     inevitable for groups that contain captures, but it can lead to a lot of
+     stack use in large patterns. The old behaviour has been restored for atomic
+     groups that do not contain any capturing parentheses.
+. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
+     suppress the check for a minimum subject length at run time. (If it was
+     given to pcre_exec() or pcre_dfa_exec() it did work.)
+. Fixed an ASCII-dependent infelicity in pcretest that would have made it
+     fail to work when decoding hex characters in data strings in EBCDIC
+     environments.
+. It appears that in at least one Mac OS environment, the isxdigit() function
+     is implemented as a macro that evaluates to its argument more than once,
+     contravening the C 90 Standard (I haven't checked a later standard). There
+     was an instance in pcretest which caused it to go wrong when processing
+     \x{...} escapes in subject strings. The has been rewritten to avoid using
+     things like p++ in the argument of isxdigit().
  Version 8.13 16-Aug-2011
-Line 140 
 Version 8.13 16-Aug-2011
+Line 452 
 Version 8.13 16-Aug-2011
      tail recursion to cut down on stack usage. Unfortunately, now that there is
      the possibility of (*THEN) occurring in these branches, tail recursion is
      no longer possible because the return has to be checked for (*THEN). These
-     two optimizations have therefore been removed.
+     two optimizations have therefore been removed. [But see 8.20/11 above.]
 . If a pattern containing \R was studied, it was assumed that \R always
      matched two bytes, thus causing the minimum subject length to be

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