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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.32 30-November-2012
5    -----------------------------
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
13    3.  Single character iterator optimizations in the JIT compiler.
15    4.  Improved JIT compiler optimizations for character ranges.
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
25    7.  Improved instruction cache flush for POWER/PowerPC.
26        Patch by Daniel Richard G.
28    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
29        grep:
31        (a) There is now no limit to the number of patterns to be matched.
33        (b) An error is given if a pattern is too long.
35        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
36            are now supported.
38        (d) --exclude-from and --include-from (multiple use) have been added.
40        (e) Exclusions and inclusions now apply to all files and directories, not
41            just to those obtained from scanning a directory recursively.
43        (f) Multiple uses of -f and --file-list are now supported.
45        (g) In a Windows environment, the default for -d has been changed from
46            "read" (the GNU grep default) to "skip", because otherwise the presence
47            of a directory in the file list provokes an error.
49        (h) The documentation has been revised and clarified in places.
51    9.  Improve the matching speed of capturing brackets.
53    10. Changed the meaning of \X so that it now matches a Unicode extended
54        grapheme cluster.
56    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
57        out POSIX threads when JIT support is configured.
59    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
61    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
62        structure could go wrong in environments where size_t is not the same size
63        as int.
65    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
66        set.
68    15. The EBCDIC support had decayed; later updates to the code had included
69        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
70        general tidy up of EBCDIC-related issues, and the documentation was also
71        not quite right. There is now a test that can be run on ASCII systems to
72        check some of the EBCDIC-related things (but is it not a full test).
74    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
75        in a small tidy to the code.
77    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
79    18. If the --only-matching (-o) option in pcregrep is specified multiple
80        times, each one causes appropriate output. For example, -o1 -o2 outputs the
81        substrings matched by the 1st and 2nd capturing parentheses. A separating
82        string can be specified by --om-separator (default empty).
84    19. Improving the first n character searches.
86    20. Turn case lists for horizontal and vertical white space into macros so that
87        they are defined only once.
89    21. This set of changes together give more compatible Unicode case-folding
90        behaviour for characters that have more than one other case when UCP
91        support is available.
93        (a) The Unicode property table now has offsets into a new table of sets of
94            three or more characters that are case-equivalent. The MultiStage2.py
95            script that generates these tables (the pcre_ucd.c file) now scans
96            CaseFolding.txt instead of UnicodeData.txt for character case
97            information.
99        (b) The code for adding characters or ranges of characters to a character
100            class has been abstracted into a generalized function that also handles
101            case-independence. In UTF-mode with UCP support, this uses the new data
102            to handle characters with more than one other case.
104        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
105            whose other case is greater than 256 are now correctly matched
106            caselessly. Previously, the high codepoint matched the low one, but not
107            vice versa.
109        (d) The processing of \h, \H, \v, and \ in character classes now makes use
110            of the new class addition function, using character lists defined as
111            macros alongside the case definitions of 20 above.
113        (e) Caseless back references now work with characters that have more than
114            one other case.
116        (f) General caseless matching of characters with more than one other case
117            is supported.
119    22. Unicode character properties were updated from Unicode 6.2.0
121    23. Improved CMake support under Windows. Patch by Daniel Richard G.
123    24. Add support for 32-bit character strings, and UTF-32
125    25. Major JIT compiler update (code refactoring and bugfixing).
126        Experimental Sparc 32 support is added.
128    26. Applied a modified version of Daniel Richard G's patch to create
129        pcre.h.generic and config.h.generic by "make" instead of in the
130        PrepareRelease script.
132    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
133        pcre_compile.c when checking for a zero character.
135    28. Introducing a native interface for JIT. Through this interface, the compiled
136        machine code can be directly executed. The purpose of this interface is to
137        provide fast pattern matching, so several sanity checks are not performed.
138        However, feature tests are still performed. The new interface provides
139        1.4x speedup compared to the old one.
141    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
142        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
143        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
145    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
146        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
147        the "old" RFC 2279). Instead, it ended up passing a negative length to
148        pcre_exec().
150    31. Add support for GCC's visibility feature to hide internal functions.
152    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
153        "unknown -C option" after outputting 0 or 1.
155    33. There is now support for generating a code coverage report for the test
156        suite in environments where gcc is the compiler and lcov is installed. This
157        is mainly for the benefit of the developers.
159    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
160        unaddressable using valgrind annotations, allowing valgrind to detect
161        invalid memory accesses. This is mainly for the benefit of the developers.
163    25. (*UTF) can now be used to start a pattern in any of the three libraries.
165    26. Give configure error if --enable-cpp but no C++ compiler found.
168    Version 8.31 06-July-2012
169    -------------------------
171    1.  Fixing a wrong JIT test case and some compiler warnings.
173    2.  Removed a bashism from the RunTest script.
175    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
176        to unsigned type, result still unsigned" that was given by an MS compiler
177        on encountering the code "-sizeof(xxx)".
179    4.  Partial matching support is added to the JIT compiler.
181    5.  Fixed several bugs concerned with partial matching of items that consist
182        of more than one character:
184        (a) /^(..)\1/ did not partially match "aba" because checking references was
185            done on an "all or nothing" basis. This also applied to repeated
186            references.
188        (b) \R did not give a hard partial match if \r was found at the end of the
189            subject.
191        (c) \X did not give a hard partial match after matching one or more
192            characters at the end of the subject.
194        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
195            a partial match for the string "\r".
197        (e) When newline was set to CRLF, the metacharacter "." did not recognize
198            a partial match for a CR character at the end of the subject string.
200    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
201        running pcretest, the text "(JIT)" added to the output whenever JIT is
202        actually used to run the match.
204    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
205        or /S+[+] with a digit between 1 and 7.
207    8.  OP_NOT now supports any UTF character not just single-byte ones.
209    9.  (*MARK) control verb is now supported by the JIT compiler.
211    10. The command "./RunTest list" lists the available tests without actually
212        running any of them. (Because I keep forgetting what they all are.)
216    12. Applied a (slightly modified) user-supplied patch that improves performance
217        when the heap is used for recursion (compiled with --disable-stack-for-
218        recursion). Instead of malloc and free for each heap frame each time a
219        logical recursion happens, frames are retained on a chain and re-used where
220        possible. This sometimes gives as much as 30% improvement.
222    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
223        call.
225    14. As documented, (*COMMIT) is now confined to within a positive assertion.
227    15. It is now possible to link pcretest with libedit as an alternative to
228        libreadline.
230    16. (*COMMIT) control verb is now supported by the JIT compiler.
232    17. The Unicode data tables have been updated to Unicode 6.1.0.
234    18. Added --file-list option to pcregrep.
236    19. Added binary file support to pcregrep, including the -a, --binary-files,
237        -I, and --text options.
239    20. The madvise function is renamed for posix_madvise for QNX compatibility
240        reasons. Fixed by Giuseppe D'Angelo.
242    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
244    22. Changed the option for creating symbolic links for 16-bit man pages from
245        -s to -sf so that re-installing does not cause issues.
247    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
249    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
250        matches in certain environments (the workspace was not being correctly
251        retained). Also added to pcre_dfa_exec() a simple plausibility check on
252        some of the workspace data at the beginning of a restart.
254    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
255        was not doing so when it should - probably a typo introduced by SVN 528
256        (change 8.10/14).
258    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
259        \w+ when the character tables indicated that \x{c4} was a word character.
260        There were several related cases, all because the tests for doing a table
261        lookup were testing for characters less than 127 instead of 255.
263    27. If a pattern contains capturing parentheses that are not used in a match,
264        their slots in the ovector are set to -1. For those that are higher than
265        any matched groups, this happens at the end of processing. In the case when
266        there were back references that the ovector was too small to contain
267        (causing temporary malloc'd memory to be used during matching), and the
268        highest capturing number was not used, memory off the end of the ovector
269        was incorrectly being set to -1. (It was using the size of the temporary
270        memory instead of the true size.)
272    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
273        ovector size, it uses memory at the end of the block that it has got.
275    29. Check for an overlong MARK name and give an error at compile time. The
276        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
278    30. JIT compiler update.
280    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
281        Rill for the patch.
283    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
285    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
287    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
288        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
289        was enabled.
291    35. Improve JIT code generation for greedy plus quantifier.
293    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
294        1 to "aa" instead of to an empty string. The bug affected repeated groups
295        that could potentially match an empty string.
297    37. Optimizing single character iterators in JIT.
299    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
300        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
301        codepoints that are too big for the mode are faulted, and in a UTF mode,
302        disallowed codepoints are also faulted.
304    39. If PCRE was compiled with UTF support, in three places in the DFA
305        matcher there was code that should only have been obeyed in UTF mode, but
306        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
307        processing when bytes with values greater than 127 were present. In 16-bit
308        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
309        both cases the values are those that cannot be the first data item in a UTF
310        character. The three items that might have provoked this were recursions,
311        possessively repeated groups, and atomic groups.
313    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
314        and pcregrep, because some OS require shared objects to be explicitly
315        passed to ld, causing the link step to fail if they are not.
317    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
318        mode, patterns that started with \h* or \R* might be incorrectly matched.
321    Version 8.30 04-February-2012
322    -----------------------------
324    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
325        name is defined in ctype.h.
327    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
328        only in quite long subpatterns.
330    3.  Removed the function pcre_info(), which has been obsolete and deprecated
331        since it was replaced by pcre_fullinfo() in February 2000.
333    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
334        match a (*MARK), and the match failed at the start of the subject, a
335        reference to memory before the start of the subject could occur. This bug
336        was introduced by fix 17 of release 8.21.
338    5.  A reference to an unset group with zero minimum repetition was giving
339        totally wrong answers (in non-JavaScript-compatibility mode). For example,
340        /(another)?(\1?)test/ matched against "hello world test". This bug was
341        introduced in release 8.13.
343    6.  Add support for 16-bit character strings (a large amount of work involving
344        many changes and refactorings).
346    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
347        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
348        from a file.
350    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
351        rounding is not applied in this particular case).
353    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
354        if they appear, or are escaped, in patterns.
356    10. Get rid of a number of -Wunused-but-set-variable warnings.
358    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
359        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
360        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
361        also returns the mark "x". This bug applied to capturing parentheses,
362        non-capturing parentheses, and atomic parentheses. It also applied to some
363        assertions.
365    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
366        information out of configure.ac instead of relying on pcre.h.generic, which
367        is not stored in the repository.
369    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
370        -lreadline.
372    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
374    15. Applied Graycode's patch to put the top-level frame on the stack rather
375        than the heap when not using the stack for recursion. This gives a
376        performance improvement in many cases when recursion is not deep.
378    16. Experimental code added to "pcretest -C" to output the stack frame size.
381    Version 8.21 12-Dec-2011
382    ------------------------
384    1.  Updating the JIT compiler.
386    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
387        are added as well.
389    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
390        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
391        calling _pcre_jit_exec. Some extra comments are added.
393    4.  (*MARK) settings inside atomic groups that do not contain any capturing
394        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
395        was introduced by change 18 for 8.20.
397    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
398        ECMA-262 standard.
400    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
401        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
402        This bug was probably introduced by change 9 of 8.13.
404    7.  While fixing 6 above, I noticed that a number of other items were being
405        incorrectly rejected as "not fixed length". This arose partly because newer
406        opcodes had not been added to the fixed-length checking code. I have (a)
407        corrected the bug and added tests for these items, and (b) arranged for an
408        error to occur if an unknown opcode is encountered while checking for fixed
409        length instead of just assuming "not fixed length". The items that were
410        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
411        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
412        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
414    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
415        being incorrectly compiled and would have given unpredicatble results.
417    9.  A possessively repeated subpattern with minimum repeat count greater than
418        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
419        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
420        the first (A) could occur when it should not.
422    10. Add a cast and remove a redundant test from the code.
424    11. JIT should use pcre_malloc/pcre_free for allocation.
426    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
427        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
428        is anything other than /usr, -L is still shown).
430    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
432    14. Perl does not support \N without a following name in a [] class; PCRE now
433        also gives an error.
435    15. If a forward reference was repeated with an upper limit of around 2000,
436        it caused the error "internal error: overran compiling workspace". The
437        maximum number of forward references (including repeats) was limited by the
438        internal workspace, and dependent on the LINK_SIZE. The code has been
439        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
440        the default depends on LINK_SIZE. There is a new upper limit (for safety)
441        of around 200,000 forward references. While doing this, I also speeded up
442        the filling in of repeated forward references.
444    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
445        incorrectly expecting the subject to contain another "a" after the start.
447    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
448        in the match, the SKIP should be ignored. This was not happening; instead
449        the SKIP was being treated as NOMATCH. For patterns such as
450        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
451        tested.
453    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
454        now much more compatible with Perl, in particular in cases where the result
455        is a non-match for a non-anchored pattern. For example, if
456        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
457        "m", where previously it did not return a name. A side effect of this
458        change is that for partial matches, the last encountered mark name is
459        returned, as for non matches. A number of tests that were previously not
460        Perl-compatible have been moved into the Perl-compatible test files. The
461        refactoring has had the pleasing side effect of removing one argument from
462        the match() function, thus reducing its stack requirements.
464    19. If the /S+ option was used in pcretest to study a pattern using JIT,
465        subsequent uses of /S (without +) incorrectly behaved like /S+.
467    21. Retrieve executable code size support for the JIT compiler and fixing
468        some warnings.
470    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
471        not work when the shorter character appeared right at the end of the
472        subject string.
474    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
475        systems.
477    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
478        output it when the /M option is used in pcretest.
480    25. The CheckMan script was not being included in the distribution. Also, added
481        an explicit "perl" to run Perl scripts from the PrepareRelease script
482        because this is reportedly needed in Windows.
484    26. If study data was being save in a file and studying had not found a set of
485        "starts with" bytes for the pattern, the data written to the file (though
486        never used) was taken from uninitialized memory and so caused valgrind to
487        complain.
489    27. Updated RunTest.bat as provided by Sheri Pierce.
491    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
493    29. Computation of memory usage for the table of capturing group names was
494        giving an unnecessarily large value.
497    Version 8.20 21-Oct-2011
498    ------------------------
500    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
501        a POSIX class. After further experiments with Perl, which convinced me that
502        Perl has bugs and confusions, a closing square bracket is no longer allowed
503        in a POSIX name. This bug also affected patterns with classes that started
504        with full stops.
506    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
507        captured substring, but while checking the failing first alternative,
508        substring 1 is temporarily captured. If the output vector supplied to
509        pcre_exec() was not big enough for this capture, the yield of the function
510        was still zero ("insufficient space for captured substrings"). This cannot
511        be totally fixed without adding another stack variable, which seems a lot
512        of expense for a edge case. However, I have improved the situation in cases
513        such as /(a)(b)x|abc/ matched against "abc", where the return code
514        indicates that fewer than the maximum number of slots in the ovector have
515        been set.
517    3.  Related to (2) above: when there are more back references in a pattern than
518        slots in the output vector, pcre_exec() uses temporary memory during
519        matching, and copies in the captures as far as possible afterwards. It was
520        using the entire output vector, but this conflicts with the specification
521        that only 2/3 is used for passing back captured substrings. Now it uses
522        only the first 2/3, for compatibility. This is, of course, another edge
523        case.
525    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
526        main code base, and can be used by building with --enable-jit. When this is
527        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
528        runtime --no-jit option is given.
530    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
531        ovector, the return from the function was zero, implying that there were
532        other matches that did not fit. The correct "exactly full" value is now
533        returned.
535    6.  If a subpattern that was called recursively or as a subroutine contained
536        (*PRUNE) or any other control that caused it to give a non-standard return,
537        invalid errors such as "Error -26 (nested recursion at the same subject
538        position)" or even infinite loops could occur.
540    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
541        computing the minimum length on reaching *ACCEPT, and so ended up with the
542        wrong value of 1 rather than 0. Further investigation indicates that
543        computing a minimum subject length in the presence of *ACCEPT is difficult
544        (think back references, subroutine calls), and so I have changed the code
545        so that no minimum is registered for a pattern that contains *ACCEPT.
547    8.  If (*THEN) was present in the first (true) branch of a conditional group,
548        it was not handled as intended. [But see 16 below.]
550    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
551        Sheri Pierce.
553    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
554        the first byte in a match must be "a".
556    11. Change 17 for 8.13 increased the recursion depth for patterns like
557        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
558        pattern contains any instances of (*THEN). If it does not, the old
559        optimizations are restored. It would be nice to do this on a per-group
560        basis, but at the moment that is not feasible.
562    12. In some environments, the output of pcretest -C is CRLF terminated. This
563        broke RunTest's code that checks for the link size. A single white space
564        character after the value is now allowed for.
566    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
567        For "fr", it uses the Windows-specific input and output files.
569    14. If (*THEN) appeared in a group that was called recursively or as a
570        subroutine, it did not work as intended. [But see next item.]
572    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
573        pattern fragments (but not containing any | characters). If A and B are
574        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
575        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
576        D. In other words, Perl considers parentheses that do not contain any |
577        characters to be part of a surrounding alternative, whereas PCRE was
578        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
579        differently. PCRE now behaves in the same way as Perl, except in the case
580        of subroutine/recursion calls such as (?1) which have in any case always
581        been different (but PCRE had them first :-).
583    16. Related to 15 above: Perl does not treat the | in a conditional group as
584        creating alternatives. Such a group is treated in the same way as an
585        ordinary group without any | characters when processing (*THEN). PCRE has
586        been changed to match Perl's behaviour.
588    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
589        RunGrepTest script failed.
591    18. Change 22 for version 13 caused atomic groups to use more stack. This is
592        inevitable for groups that contain captures, but it can lead to a lot of
593        stack use in large patterns. The old behaviour has been restored for atomic
594        groups that do not contain any capturing parentheses.
596    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
597        suppress the check for a minimum subject length at run time. (If it was
598        given to pcre_exec() or pcre_dfa_exec() it did work.)
600    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
601        fail to work when decoding hex characters in data strings in EBCDIC
602        environments.
604    21. It appears that in at least one Mac OS environment, the isxdigit() function
605        is implemented as a macro that evaluates to its argument more than once,
606        contravening the C 90 Standard (I haven't checked a later standard). There
607        was an instance in pcretest which caused it to go wrong when processing
608        \x{...} escapes in subject strings. The has been rewritten to avoid using
609        things like p++ in the argument of isxdigit().
612    Version 8.13 16-Aug-2011
613    ------------------------
615    1.  The Unicode data tables have been updated to Unicode 6.0.0.
617    2.  Two minor typos in pcre_internal.h have been fixed.
619    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
620        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
621        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
623    4.  There were a number of related bugs in the code for matching backrefences
624        caselessly in UTF-8 mode when codes for the characters concerned were
625        different numbers of bytes. For example, U+023A and U+2C65 are an upper
626        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
627        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
628        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
629        2-byte code at the end of the subject (it thought there wasn't enough data
630        left).
632    5.  Comprehensive information about what went wrong is now returned by
633        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
634        as the output vector has at least 2 elements. The offset of the start of
635        the failing character and a reason code are placed in the vector.
637    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
638        now returned is for the first byte of the failing character, instead of the
639        last byte inspected. This is an incompatible change, but I hope it is small
640        enough not to be a problem. It makes the returned offset consistent with
641        pcre_exec() and pcre_dfa_exec().
643    7.  pcretest now gives a text phrase as well as the error number when
644        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
645        failure, the offset and reason code are output.
647    8.  When \R was used with a maximizing quantifier it failed to skip backwards
648        over a \r\n pair if the subsequent match failed. Instead, it just skipped
649        back over a single character (\n). This seems wrong (because it treated the
650        two characters as a single entity when going forwards), conflicts with the
651        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
652        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
653        has been changed.
655    9.  Some internal refactoring has changed the processing so that the handling
656        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
657        time (the PCRE_DOTALL option was changed this way some time ago: version
658        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
659        which was always a bit of a fudge. It also means that there is one less
660        argument for the match() function, which reduces its stack requirements
661        slightly. This change also fixes an incompatibility with Perl: the pattern
662        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
664    10. More internal refactoring has drastically reduced the number of recursive
665        calls to match() for possessively repeated groups such as (abc)++ when
666        using pcre_exec().
668    11. While implementing 10, a number of bugs in the handling of groups were
669        discovered and fixed:
671        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
672        (a|)*(?1) gave a compile-time internal error.
673        ((a|)+)+  did not notice that the outer group could match an empty string.
674        (^a|^)+   was not marked as anchored.
675        (.*a|.*)+ was not marked as matching at start or after a newline.
677    12. Yet more internal refactoring has removed another argument from the match()
678        function. Special calls to this function are now indicated by setting a
679        value in a variable in the "match data" data block.
681    13. Be more explicit in pcre_study() instead of relying on "default" for
682        opcodes that mean there is no starting character; this means that when new
683        ones are added and accidentally left out of pcre_study(), testing should
684        pick them up.
686    14. The -s option of pcretest has been documented for ages as being an old
687        synonym of -m (show memory usage). I have changed it to mean "force study
688        for every regex", that is, assume /S for every regex. This is similar to -i
689        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
690        using it. It makes it easier to run collections of tests with and without
691        study enabled, and thereby test pcre_study() more easily. All the standard
692        tests are now run with and without -s (but some patterns can be marked as
693        "never study" - see 20 below).
695    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
696        restoration of the capturing data to the outer values was not happening
697        correctly.
699    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
700        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
701        pattern had matched an empty string, and so incorrectly returned a no
702        match.
704    17. There was optimizing code for the last branch of non-capturing parentheses,
705        and also for the obeyed branch of a conditional subexpression, which used
706        tail recursion to cut down on stack usage. Unfortunately, now that there is
707        the possibility of (*THEN) occurring in these branches, tail recursion is
708        no longer possible because the return has to be checked for (*THEN). These
709        two optimizations have therefore been removed. [But see 8.20/11 above.]
711    18. If a pattern containing \R was studied, it was assumed that \R always
712        matched two bytes, thus causing the minimum subject length to be
713        incorrectly computed because \R can also match just one byte.
715    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
716        was incorrectly computed.
718    20. If /S is present twice on a test pattern in pcretest input, it now
719        *disables* studying, thereby overriding the use of -s on the command line
720        (see 14 above). This is necessary for one or two tests to keep the output
721        identical in both cases.
723    21. When (*ACCEPT) was used in an assertion that matched an empty string and
724        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
726    22. When an atomic group that contained a capturing parenthesis was
727        successfully matched, but the branch in which it appeared failed, the
728        capturing was not being forgotten if a higher numbered group was later
729        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
730        group 1 to "a", when in fact it should be unset. This applied to multi-
731        branched capturing and non-capturing groups, repeated or not, and also to
732        positive assertions (capturing in negative assertions does not happen
733        in PCRE) and also to nested atomic groups.
735    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
736        subject after a captured substring, to make it easier to tell which of a
737        number of identical substrings has been captured.
739    24. The way atomic groups are processed by pcre_exec() has been changed so that
740        if they are repeated, backtracking one repetition now resets captured
741        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
742        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
743        "aaa". Previously, it would have been "a". As part of this code
744        refactoring, the way recursive calls are handled has also been changed.
746    25. If an assertion condition captured any substrings, they were not passed
747        back unless some other capturing happened later. For example, if
748        (?(?=(a))a) was matched against "a", no capturing was returned.
750    26. When studying a pattern that contained subroutine calls or assertions,
751        the code for finding the minimum length of a possible match was handling
752        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
753        group 1 called group 2 while simultaneously a separate group 2 called group
754        1). A stack overflow occurred in this case. I have fixed this by limiting
755        the recursion depth to 10.
757    27. Updated RunTest.bat in the distribution to the version supplied by Tom
758        Fortmann. This supports explicit test numbers on the command line, and has
759        argument validation and error reporting.
761    28. An instance of \X with an unlimited repeat could fail if at any point the
762        first character it looked at was a mark character.
764    29. Some minor code refactoring concerning Unicode properties and scripts
765        should reduce the stack requirement of match() slightly.
767    30. Added the '=' option to pcretest to check the setting of unused capturing
768        slots at the end of the pattern, which are documented as being -1, but are
769        not included in the return count.
771    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
772        compiled something random. Now it gives a compile-time error (as does
773        Perl).
775    32. A *MARK encountered during the processing of a positive assertion is now
776        recorded and passed back (compatible with Perl).
778    33. If --only-matching or --colour was set on a pcregrep call whose pattern
779        had alternative anchored branches, the search for a second match in a line
780        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
781        matched the line "0102" twice. The same bug affected patterns that started
782        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
783        twice.
785    34. Previously, PCRE did not allow quantification of assertions. However, Perl
786        does, and because of capturing effects, quantifying parenthesized
787        assertions may at times be useful. Quantifiers are now allowed for
788        parenthesized assertions.
790    35. A minor code tidy in pcre_compile() when checking options for \R usage.
792    36. \g was being checked for fancy things in a character class, when it should
793        just be a literal "g".
795    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
796        appearance of a nested POSIX class supersedes an apparent external class.
797        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
798        unescaped square brackets may also appear as part of class names. For
799        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
800        more like Perl. (But see 8.20/1 above.)
802    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
803        was because it thought it was \N{name}, which is not supported).
805    39. Add minix to OS list not supporting the -S option in pcretest.
807    40. PCRE tries to detect cases of infinite recursion at compile time, but it
808        cannot analyze patterns in sufficient detail to catch mutual recursions
809        such as ((?1))((?2)). There is now a runtime test that gives an error if a
810        subgroup is called recursively as a subpattern for a second time at the
811        same position in the subject string. In previous releases this might have
812        been caught by the recursion limit, or it might have run out of stack.
814    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
815        happen only once. PCRE was, however incorrectly giving a compile time error
816        "recursive call could loop indefinitely" because it cannot analyze the
817        pattern in sufficient detail. The compile time test no longer happens when
818        PCRE is compiling a conditional subpattern, but actual runaway loops are
819        now caught at runtime (see 40 above).
821    42. It seems that Perl allows any characters other than a closing parenthesis
822        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
823        has been changed to be the same.
825    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
826        as not to get warnings when autogen.sh is called. Also changed
827        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
829    44. To help people who use pcregrep to scan files containing exceedingly long
830        lines, the following changes have been made:
832        (a) The default value of the buffer size parameter has been increased from
833            8K to 20K. (The actual buffer used is three times this size.)
835        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
836            PCRE is built.
838        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
839            to be set at run time.
841        (d) Numerical values in pcregrep options can be followed by K or M, for
842            example --buffer-size=50K.
844        (e) If a line being scanned overflows pcregrep's buffer, an error is now
845            given and the return code is set to 2.
847    45. Add a pointer to the latest mark to the callout data block.
849    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
850        partial match of an empty string instead of no match. This was specific to
851        the use of ".".
853    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
854        complete match instead of a partial match. This bug was dependent on both
855        the PCRE_UTF8 and PCRE_DOTALL options being set.
857    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
858        starting byte set, because \b was not being ignored.
861    Version 8.12 15-Jan-2011
862    ------------------------
864    1.  Fixed some typos in the markup of the man pages, and wrote a script that
865        checks for such things as part of the documentation building process.
867    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
868        --match-limit and --recursion-limit options (added for 8.11). In
869        particular, this made one of the standard tests fail. (The integer value
870        went into the wrong half of a long int.)
872    3.  If the --colour option was given to pcregrep with -v (invert match), it
873        did strange things, either producing crazy output, or crashing. It should,
874        of course, ignore a request for colour when reporting lines that do not
875        match.
877    4.  Another pcregrep bug caused similar problems if --colour was specified with
878        -M (multiline) and the pattern match finished with a line ending.
880    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
881        matched in multiline mode, the following line was shown as part of the
882        match. This seems wrong, so I have changed it.
884    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
885        the check for further matches in the same line (so they could be coloured)
886        to overrun the end of the current line. If another match was found, it was
887        incorrectly shown (and then shown again when found in the next line).
889    7.  If pcregrep was compiled under Windows, there was a reference to the
890        function pcregrep_exit() before it was defined. I am assuming this was
891        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
892        reported by a user. I've moved the definition above the reference.
895    Version 8.11 10-Dec-2010
896    ------------------------
898    1.  (*THEN) was not working properly if there were untried alternatives prior
899        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
900        backtracked to try for "b" instead of moving to the next alternative branch
901        at the same level (in this case, to look for "c"). The Perl documentation
902        is clear that when (*THEN) is backtracked onto, it goes to the "next
903        alternative in the innermost enclosing group".
905    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
906        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
907        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
908        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
909        (*THEN).
911    3.  If \s appeared in a character class, it removed the VT character from
912        the class, even if it had been included by some previous item, for example
913        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
914        of \s, but is part of the POSIX "space" class.)
916    4.  A partial match never returns an empty string (because you can always
917        match an empty string at the end of the subject); however the checking for
918        an empty string was starting at the "start of match" point. This has been
919        changed to the "earliest inspected character" point, because the returned
920        data for a partial match starts at this character. This means that, for
921        example, /(?<=abc)def/ gives a partial match for the subject "abc"
922        (previously it gave "no match").
924    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
925        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
926        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
927        has an implication that the given string is incomplete (because a partial
928        match is preferred over a full match). For this reason, these items now
929        give a partial match in this situation. [Aside: previously, the one case
930        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
931        match rather than a full match, which was wrong by the old rules, but is
932        now correct.]
934    6.  There was a bug in the handling of #-introduced comments, recognized when
935        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
936        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
937        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
938        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
939        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
940        places in pcre_compile().
942    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
943        comments when looking ahead for named forward references to subpatterns,
944        the only newline sequence it recognized was NL. It now handles newlines
945        according to the set newline convention.
947    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
948        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
949        cater for a lack of strerror(). These oversights have been fixed.
951    9.  Added --match-limit and --recursion-limit to pcregrep.
953    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
955    11. When the -o option was used, pcregrep was setting a return code of 1, even
956        when matches were found, and --line-buffered was not being honoured.
958    12. Added an optional parentheses number to the -o and --only-matching options
959        of pcregrep.
961    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
962        can match an empty string. The code to do it in pcretest and pcredemo
963        needed fixing:
965        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
966            only one byte after an empty string match just before CRLF (this case
967            just got forgotten; "any" and "anycrlf" were OK).
969        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
970            mode when an empty string match preceded an ASCII character followed by
971            a non-ASCII character. (The code for advancing by one character rather
972            than one byte was nonsense.)
974        (c) The pcredemo.c sample program did not have any code at all to handle
975            the cases when CRLF is a valid newline sequence.
977    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
978        as a starting offset was within the subject string. There is now a new
979        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
980        negative or greater than the length of the string. In order to test this,
981        pcretest is extended to allow the setting of negative starting offsets.
983    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
984        starting offset points to the beginning of a UTF-8 character was
985        unnecessarily clumsy. I tidied it up.
987    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
988        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
990    17. Nobody had reported that the --include_dir option, which was added in
991        release 7.7 should have been called --include-dir (hyphen, not underscore)
992        for compatibility with GNU grep. I have changed it to --include-dir, but
993        left --include_dir as an undocumented synonym, and the same for
994        --exclude-dir, though that is not available in GNU grep, at least as of
995        release 2.5.4.
997    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
998        characters from a string of bytes) have been redefined so as not to use
999        loops, in order to improve performance in some environments. At the same
1000        time, I abstracted some of the common code into auxiliary macros to save
1001        repetition (this should not affect the compiled code).
1003    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1004        compile-time error is now given if \c is not followed by an ASCII
1005        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1006        different, and any byte value is allowed.)
1008    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1009        START_OPTIMIZE option, which is now allowed at compile time - but just
1010        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1011        to pcregrep and other applications that have no direct access to PCRE
1012        options. The new /Y option in pcretest sets this option when calling
1013        pcre_compile().
1015    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1016        back references. Groups containing recursive back references were forced to
1017        be atomic by that change, but in the case of named groups, the amount of
1018        memory required was incorrectly computed, leading to "Failed: internal
1019        error: code overflow". This has been fixed.
1021    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1022        pcretest.c, to avoid build problems in some Borland environments.
1025    Version 8.10 25-Jun-2010
1026    ------------------------
1028    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1029        THEN.
1031    2.  (*ACCEPT) was not working when inside an atomic group.
1033    3.  Inside a character class, \B is treated as a literal by default, but
1034        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1035        causes the error). The code is unchanged, but I tidied the documentation.
1037    4.  Inside a character class, PCRE always treated \R and \X as literals,
1038        whereas Perl faults them if its -w option is set. I have changed PCRE so
1039        that it faults them when PCRE_EXTRA is set.
1041    5.  Added support for \N, which always matches any character other than
1042        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1044    6.  When compiling pcregrep with newer versions of gcc which may have
1045        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1046        declared with attribute warn_unused_result" were given. Just casting the
1047        result to (void) does not stop the warnings; a more elaborate fudge is
1048        needed. I've used a macro to implement this.
1050    7.  Minor change to pcretest.c to avoid a compiler warning.
1052    8.  Added four artifical Unicode properties to help with an option to make
1053        \s etc use properties (see next item). The new properties are: Xan
1054        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1056    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1057        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1058        this option. Modified pcretest to add /W to test this facility. Added
1059        REG_UCP to make it available via the POSIX interface.
1061    10. Added --line-buffered to pcregrep.
1063    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1064        studied, and the match started with a letter with a code point greater than
1065        127 whose first byte was different to the first byte of the other case of
1066        the letter, the other case of this starting letter was not recognized
1067        (#976).
1069    12. If a pattern that was studied started with a repeated Unicode property
1070        test, for example, \p{Nd}+, there was the theoretical possibility of
1071        setting up an incorrect bitmap of starting bytes, but fortunately it could
1072        not have actually happened in practice until change 8 above was made (it
1073        added property types that matched character-matching opcodes).
1075    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1076        possible starting bytes for non-anchored patterns.
1078    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1079        \R, and also a number of cases that involve Unicode properties, both
1080        explicit and implicit when PCRE_UCP is set.
1082    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1083        input, it could crash or give wrong results if characters with values
1084        greater than 0xc0 were present in the subject string. (Detail: it assumed
1085        UTF-8 input when processing these items.)
1087    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1088        size_t is 64-bit (#991).
1090    17. Added a check for running out of memory when PCRE is compiled with
1091        --disable-stack-for-recursion (#990).
1093    18. If the last data line in a file for pcretest does not have a newline on
1094        the end, a newline was missing in the output.
1096    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1097        less than 128) in its various bitmaps. However, there is a facility for
1098        generating tables according to the current locale when PCRE is compiled. It
1099        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1100        characters, are recognized by isspace() and therefore were getting set in
1101        these tables, and indeed these tables seem to approximate to ISO 8859. This
1102        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1103        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1104        which of course cannot start UTF-8 characters. I have changed the code so
1105        that only real ASCII characters (less than 128) and the correct starting
1106        bytes for UTF-8 encodings are set for characters greater than 127 when in
1107        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1108        altogether.)
1110    20. Added the /T option to pcretest so as to be able to run tests with non-
1111        standard character tables, thus making it possible to include the tests
1112        used for 19 above in the standard set of tests.
1114    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1115        reference to a subpattern the other side of a comment that contains an
1116        opening parenthesis caused either an internal compiling error, or a
1117        reference to the wrong subpattern.
1120    Version 8.02 19-Mar-2010
1121    ------------------------
1123    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1125    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1126        configured.
1128    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1129        original author of that file, following a query about its status.
1131    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1132        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1134    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1135        quantifier applied to a forward-referencing subroutine call, could compile
1136        incorrect code or give the error "internal error: previously-checked
1137        referenced subpattern not found".
1139    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1140        variables to point to external functions. For these systems, therefore,
1141        pcre_malloc etc. are now initialized to local functions that call the
1142        relevant global functions.
1144    7.  There were two entries missing in the vectors called coptable and poptable
1145        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1146        I've fixed the data, and added a kludgy way of testing at compile time that
1147        the lengths are correct (equal to the number of opcodes).
1149    8.  Following on from 7, I added a similar kludge to check the length of the
1150        eint vector in pcreposix.c.
1152    9.  Error texts for pcre_compile() are held as one long string to avoid too
1153        much relocation at load time. To find a text, the string is searched,
1154        counting zeros. There was no check for running off the end of the string,
1155        which could happen if a new error number was added without updating the
1156        string.
1158    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1160    11. \K was not working if it appeared in an atomic group or in a group that
1161        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1162        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1163        the assertion is positive, but not if it is negative.
1165    12. Change 11 fortuitously reduced the size of the stack frame used in the
1166        "match()" function of pcre_exec.c by one pointer. Forthcoming
1167        implementation of support for (*MARK) will need an extra pointer on the
1168        stack; I have reserved it now, so that the stack frame size does not
1169        decrease.
1171    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1172        item in branch that calls a recursion is a subroutine call - as in the
1173        second branch in the above example - was incorrectly given the compile-
1174        time error "recursive call could loop indefinitely" because pcre_compile()
1175        was not correctly checking the subroutine for matching a non-empty string.
1177    14. The checks for overrunning compiling workspace could trigger after an
1178        overrun had occurred. This is a "should never occur" error, but it can be
1179        triggered by pathological patterns such as hundreds of nested parentheses.
1180        The checks now trigger 100 bytes before the end of the workspace.
1182    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1185    Version 8.01 19-Jan-2010
1186    ------------------------
1188    1.  If a pattern contained a conditional subpattern with only one branch (in
1189        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1190        computed the wrong minimum data length (which is of course zero for such
1191        subpatterns). This could cause incorrect "no match" results.
1193    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1194        the pattern is reset in the first branch, pcre_compile() failed with
1195        "internal error: code overflow at offset...". This happened only when
1196        the reset was to the original external option setting. (An optimization
1197        abstracts leading options settings into an external setting, which was the
1198        cause of this.)
1200    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1201        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1202        assertion pattern did not match (meaning that the assertion was true), it
1203        was incorrectly treated as false if the SKIP had been reached during the
1204        matching. This also applied to assertions used as conditions.
1206    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1207        assertion subpattern, including such a pattern used as a condition,
1208        unpredictable results occurred, instead of the error return
1211    5.  The C++ GlobalReplace function was not working like Perl for the special
1212        situation when an empty string is matched. It now does the fancy magic
1213        stuff that is necessary.
1215    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1216        removed. (These were left over from very, very early versions of PCRE.)
1218    7.  Some cosmetic changes to the code to make life easier when compiling it
1219        as part of something else:
1221        (a) Change DEBUG to PCRE_DEBUG.
1223        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1224            called "current" as "current_branch", to prevent a collision with the
1225            Linux macro when compiled as a kernel module.
1227        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1228            prevent a collision with the Linux macro when compiled as a kernel
1229            module.
1231    8.  In pcre_compile() there are some checks for integer overflows that used to
1232        cast potentially large values to (double). This has been changed to that
1233        when building, a check for int64_t is made, and if it is found, it is used
1234        instead, thus avoiding the use of floating point arithmetic. (There is no
1235        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1236        double.
1238    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1239        2005 (difference between two addresses compared to an unsigned value).
1241    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1242        custom one, because of the following reported problem in Windows:
1244          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1245              under Win32.
1246          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1247              therefore missing the function definition.
1248          - The compiler thus generates a "C" signature for the test function.
1249          - The linker fails to find the "C" function.
1250          - PCRE fails to configure if asked to do so against libbz2.
1252    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1253        messages were output:
1255          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1256          rerunning libtoolize, to keep the correct libtool macros in-tree.
1257          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1259        I have done both of these things.
1261    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1262        most of the time, it *can* run out if it is given a pattern that contains a
1263        runaway infinite recursion. I updated the discussion in the pcrestack man
1264        page.
1266    13. Now that we have gone to the x.xx style of version numbers, the minor
1267        version may start with zero. Using 08 or 09 is a bad idea because users
1268        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1269        interpreted as invalid octal numbers. I've updated the previous comment in
1270        configure.ac, and also added a check that gives an error if 08 or 09 are
1271        used.
1273    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1274        causing partial matching to fail when the end of the subject matched \W
1275        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1277    15. There were some discrepancies between the declarations in pcre_internal.h
1278        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1279        their definitions. The declarations used "const uschar *" and the
1280        definitions used USPTR. Even though USPTR is normally defined as "const
1281        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1282        reported that: "This difference in casting confuses some C++ compilers, for
1283        example, SunCC recognizes above declarations as different functions and
1284        generates broken code for hbpcre." I have changed the declarations to use
1285        USPTR.
1287    16. GNU libtool is named differently on some systems. The autogen.sh script now
1288        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1289        (FreeBSD).
1291    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1292        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1293        comment: "Figure out how to create a longlong from a string: strtoll and
1294        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1295        instance, but it only takes 2 args instead of 3!"
1297    18. A subtle bug concerned with back references has been fixed by a change of
1298        specification, with a corresponding code fix. A pattern such as
1299        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1300        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1301        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1302        same bug. Such groups have to be quantified to be useful, or contained
1303        inside another quantified group. (If there's no repetition, the reference
1304        can never match.) The problem arises because, having left the group and
1305        moved on to the rest of the pattern, a later failure that backtracks into
1306        the group uses the captured value from the final iteration of the group
1307        rather than the correct earlier one. I have fixed this in PCRE by forcing
1308        any group that contains a reference to itself to be an atomic group; that
1309        is, there cannot be any backtracking into it once it has completed. This is
1310        similar to recursive and subroutine calls.
1313    Version 8.00 19-Oct-09
1314    ----------------------
1316    1.  The table for translating pcre_compile() error codes into POSIX error codes
1317        was out-of-date, and there was no check on the pcre_compile() error code
1318        being within the table. This could lead to an OK return being given in
1319        error.
1321    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1322        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1323        in a Windows environment.
1325    3.  The pcregrep --count option prints the count for each file even when it is
1326        zero, as does GNU grep. However, pcregrep was also printing all files when
1327        --files-with-matches was added. Now, when both options are given, it prints
1328        counts only for those files that have at least one match. (GNU grep just
1329        prints the file name in this circumstance, but including the count seems
1330        more useful - otherwise, why use --count?) Also ensured that the
1331        combination -clh just lists non-zero counts, with no names.
1333    4.  The long form of the pcregrep -F option was incorrectly implemented as
1334        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1335        but it seems right to fix it, and I didn't think it was worth preserving
1336        the old behaviour.
1338    5.  The command line items --regex=pattern and --regexp=pattern were not
1339        recognized by pcregrep, which required --regex pattern or --regexp pattern
1340        (with a space rather than an '='). The man page documented the '=' forms,
1341        which are compatible with GNU grep; these now work.
1343    6.  No libpcreposix.pc file was created for pkg-config; there was just
1344        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1346    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1347        when UCP support is not needed, by modifying the Python script that
1348        generates it from Unicode data files. This should not matter if the module
1349        is correctly used as a library, but I received one complaint about 50K of
1350        unwanted data. My guess is that the person linked everything into his
1351        program rather than using a library. Anyway, it does no harm.
1353    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1354        was a minimum greater than 1 for a wide character in a possessive
1355        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1356        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1357        character. Chaos in the form of incorrect output or a compiling loop could
1358        result.
1360    9.  The restrictions on what a pattern can contain when partial matching is
1361        requested for pcre_exec() have been removed. All patterns can now be
1362        partially matched by this function. In addition, if there are at least two
1363        slots in the offset vector, the offset of the earliest inspected character
1364        for the match and the offset of the end of the subject are set in them when
1365        PCRE_ERROR_PARTIAL is returned.
1367    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1368        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1369        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1370        and may be more useful for multi-segment matching.
1372    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1373        used to be given if ever the end of the subject was reached; now it is
1374        given only if matching could not proceed because another character was
1375        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1376        string "Z", which now yields "no match" instead of "partial match". In the
1377        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1378        final character ended with (*FAIL).
1380    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1381        if the pattern had a "must contain" character that was already found in the
1382        earlier partial match, unless partial matching was again requested. For
1383        example, with the pattern /dog.(body)?/, the "must contain" character is
1384        "g". If the first part-match was for the string "dog", restarting with
1385        "sbody" failed. This bug has been fixed.
1387    13. The string returned by pcre_dfa_exec() after a partial match has been
1388        changed so that it starts at the first inspected character rather than the
1389        first character of the match. This makes a difference only if the pattern
1390        starts with a lookbehind assertion or \b or \B (\K is not supported by
1391        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1392        matching functions compatible, and I think it's the right thing to do.
1394    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1395        so that the demonstration program is easily available in environments where
1396        PCRE has not been installed from source.
1398    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1399        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1400        library.
1402    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1403        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1404        is not the first non-POSIX option to be added. Clearly some people find
1405        these options useful.
1407    17. If a caller to the POSIX matching function regexec() passes a non-zero
1408        value for nmatch with a NULL value for pmatch, the value of
1409        nmatch is forced to zero.
1411    18. RunGrepTest did not have a test for the availability of the -u option of
1412        the diff command, as RunTest does. It now checks in the same way as
1413        RunTest, and also checks for the -b option.
1415    19. If an odd number of negated classes containing just a single character
1416        interposed, within parentheses, between a forward reference to a named
1417        subpattern and the definition of the subpattern, compilation crashed with
1418        an internal error, complaining that it could not find the referenced
1419        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1420        [The bug was that it was starting one character too far in when skipping
1421        over the character class, thus treating the ] as data rather than
1422        terminating the class. This meant it could skip too much.]
1424    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1425        /g option in pcretest when the pattern contains \K, which makes it possible
1426        to have an empty string match not at the start, even when the pattern is
1427        anchored. Updated pcretest and pcredemo to use this option.
1429    21. If the maximum number of capturing subpatterns in a recursion was greater
1430        than the maximum at the outer level, the higher number was returned, but
1431        with unset values at the outer level. The correct (outer level) value is
1432        now given.
1434    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1435        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1436        make it do so. The string so far is captured, making this feature
1437        compatible with Perl.
1439    23. The tests have been re-organized, adding tests 11 and 12, to make it
1440        possible to check the Perl 5.10 features against Perl 5.10.
1442    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1443        pattern matches a fixed length string. PCRE did not allow this; now it
1444        does. Neither allows recursion.
1446    25. I finally figured out how to implement a request to provide the minimum
1447        length of subject string that was needed in order to match a given pattern.
1448        (It was back references and recursion that I had previously got hung up
1449        on.) This code has now been added to pcre_study(); it finds a lower bound
1450        to the length of subject needed. It is not necessarily the greatest lower
1451        bound, but using it to avoid searching strings that are too short does give
1452        some useful speed-ups. The value is available to calling programs via
1453        pcre_fullinfo().
1455    26. While implementing 25, I discovered to my embarrassment that pcretest had
1456        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1457        study optimizations had never been tested with that matching function.
1458        Oops. What is worse, even when it was passed study data, there was a bug in
1459        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1460        were also very few tests of studied patterns with pcre_dfa_exec().
1462    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1463        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1464        on the other side of the coin, they are no longer allowed to have different
1465        names, because these cannot be distinguished in PCRE, and this has caused
1466        confusion. (This is a difference from Perl.)
1468    28. When duplicate subpattern names are present (necessarily with different
1469        numbers, as required by 27 above), and a test is made by name in a
1470        conditional pattern, either for a subpattern having been matched, or for
1471        recursion in such a pattern, all the associated numbered subpatterns are
1472        tested, and the overall condition is true if the condition is true for any
1473        one of them. This is the way Perl works, and is also more like the way
1474        testing by number works.
1477    Version 7.9 11-Apr-09
1478    ---------------------
1480    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1481        (pcretest), all targets were linked against these libraries. This included
1482        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1483        libraries. This caused unwanted dependencies to be created. This problem
1484        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1485        pcretest is linked with readline.
1487    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1488        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1489        moved outside it again, because FALSE and TRUE are already defined in AIX,
1490        but BOOL is not.
1492    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1493        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1495    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1496        hyphens) following file names and line numbers when outputting matching
1497        lines. This is not true; no spaces are inserted. I have also clarified the
1498        wording for the --colour (or --color) option.
1500    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1501        was not coloured; this is different to GNU grep, so I have changed it to be
1502        the same.
1504    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1505        each matching line was coloured. Now it goes on to look for further matches
1506        of any of the test patterns, which is the same behaviour as GNU grep.
1508    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1509        doesn't make sense to accept an empty string match in pcregrep, so I have
1510        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1511        seems to be how GNU grep behaves.
1513    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1514        start or after a newline", because the conditional assertion was not being
1515        correctly handled. The rule now is that both the assertion and what follows
1516        in the first alternative must satisfy the test.
1518    9.  If auto-callout was enabled in a pattern with a conditional group whose
1519        condition was an assertion, PCRE could crash during matching, both with
1520        pcre_exec() and pcre_dfa_exec().
1522    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1523        used for matching.
1525    11. Unicode property support in character classes was not working for
1526        characters (bytes) greater than 127 when not in UTF-8 mode.
1528    12. Added the -M command line option to pcretest.
1530    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1532    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1534    16. Added comments and documentation about mis-use of no_arg in the C++
1535        wrapper.
1537    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1538        from Martin Jerabek that uses macro names for all relevant character and
1539        string constants.
1541    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1542        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1543        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1544        these, but not everybody uses configure.
1546    19. A conditional group that had only one branch was not being correctly
1547        recognized as an item that could match an empty string. This meant that an
1548        enclosing group might also not be so recognized, causing infinite looping
1549        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1550        with the subject "ab", where knowledge that the repeated group can match
1551        nothing is needed in order to break the loop.
1553    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1554        exec(), but without supplying a callout function, matching went wrong.
1556    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1557        leak if the size of the offset vector was greater than 30. When the vector
1558        is smaller, the saved offsets during recursion go onto a local stack
1559        vector, but for larger vectors malloc() is used. It was failing to free
1560        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1561        error, in fact).
1563    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1564        heapframe that is used only when UTF-8 support is enabled. This caused no
1565        problem, but was untidy.
1567    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1568        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1569        included within another project.
1571    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1572        slightly modified by me:
1574          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1575              not building pcregrep.
1577          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1578              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1580    25. Forward references, both numeric and by name, in patterns that made use of
1581        duplicate group numbers, could behave incorrectly or give incorrect errors,
1582        because when scanning forward to find the reference group, PCRE was not
1583        taking into account the duplicate group numbers. A pattern such as
1584        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1586    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1587        the feature of a custom pointer more persuasive (as requested by a user).
1589    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1590        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1591        pre-defined.
1593    28. Added support for (*UTF8) at the start of a pattern.
1595    29. Arrange for flags added by the "release type" setting in CMake to be shown
1596        in the configuration summary.
1599    Version 7.8 05-Sep-08
1600    ---------------------
1602    1.  Replaced UCP searching code with optimized version as implemented for Ad
1603        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1604        stage table and inline lookup instead of a function, giving speed ups of 2
1605        to 5 times on some simple patterns that I tested. Permission was given to
1606        distribute the MultiStage2.py script that generates the tables (it's not in
1607        the tarball, but is in the Subversion repository).
1609    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1610        scripts.
1612    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1613        a group with a zero qualifier. The result of the study could be incorrect,
1614        or the function might crash, depending on the pattern.
1616    4.  Caseless matching was not working for non-ASCII characters in back
1617        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1618        It now works when Unicode Property Support is available.
1620    5.  In pcretest, an escape such as \x{de} in the data was always generating
1621        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1622        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1623        truncation.
1625    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1627    7.  Added two (int) casts to pcregrep when printing the difference of two
1628        pointers, in case they are 64-bit values.
1630    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1631        test 2 if it fails.
1633    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1634        and a #define of that name to empty if it is not externally set. This is to
1635        allow users of MSVC to set it if necessary.
1637    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1638        the convenience functions in the pcre_get.c source file.
1640    11. An option change at the start of a pattern that had top-level alternatives
1641        could cause overwriting and/or a crash. This command provoked a crash in
1642        some environments:
1644          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1646        This potential security problem was recorded as CVE-2008-2371.
1648    12. For a pattern where the match had to start at the beginning or immediately
1649        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1650        pcre_dfa_exec() could read past the end of the passed subject if there was
1651        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1652        pcretest so that it places the subject at the end of its malloc-ed buffer.
1654    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1655        exec() might read past the end of the data buffer in UTF-8 mode.
1657    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1658        the data contained the byte 0x85 as part of a UTF-8 character within its
1659        first line. This applied both to normal and DFA matching.
1661    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1662        /^[^d]*?$/8 failed to match "abc".
1664    16. Added a missing copyright notice to pcrecpp_internal.h.
1666    17. Make it more clear in the documentation that values returned from
1667        pcre_exec() in ovector are byte offsets, not character counts.
1669    18. Tidied a few places to stop certain compilers from issuing warnings.
1671    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1672        supplied by Stefan Weber. I made a further small update for 7.8 because
1673        there is a change of source arrangements: the pcre_searchfuncs.c module is
1674        replaced by pcre_ucd.c.
1677    Version 7.7 07-May-08
1678    ---------------------
1680    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1681        a string to a long long, pretend we don't even have a long long." This is
1682        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1684    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1685        pre-7.6 versions, which defined a global no_arg variable instead of putting
1686        it in the RE class. (See also #8 below.)
1688    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1689        Lopes.
1691    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1693        (1) The include/exclude patterns were being applied to the whole pathnames
1694            of files, instead of just to the final components.
1696        (2) If there was more than one level of directory, the subdirectories were
1697            skipped unless they satisfied the include/exclude conditions. This is
1698            inconsistent with GNU grep (and could even be seen as contrary to the
1699            pcregrep specification - which I improved to make it absolutely clear).
1700            The action now is always to scan all levels of directory, and just
1701            apply the include/exclude patterns to regular files.
1703    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1704        --exclude_dir in the tests to avoid scanning .svn directories.
1706    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1707        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1708        doesn't support NULs in patterns.
1710    7.  Added some missing "const"s to declarations of static tables in
1711        pcre_compile.c and pcre_dfa_exec.c.
1713    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1714        caused by fix #2  above. (Subsequently also a second patch to fix the
1715        first patch. And a third patch - this was a messy problem.)
1717    9.  Applied Craig's patch to remove the use of push_back().
1719    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1720        matching function regexec().
1722    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1723        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1724        references. PCRE supports relative numbers with this syntax (I don't think
1725        Oniguruma does).
1727    12. Previously, a group with a zero repeat such as (...){0} was completely
1728        omitted from the compiled regex. However, this means that if the group
1729        was called as a subroutine from elsewhere in the pattern, things went wrong
1730        (an internal error was given). Such groups are now left in the compiled
1731        pattern, with a new opcode that causes them to be skipped at execution
1732        time.
1734    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1735        to the way PCRE behaves:
1737        (a) A lone ] character is dis-allowed (Perl treats it as data).
1739        (b) A back reference to an unmatched subpattern matches an empty string
1740            (Perl fails the current match path).
1742        (c) A data ] in a character class must be notated as \] because if the
1743            first data character in a class is ], it defines an empty class. (In
1744            Perl it is not possible to have an empty class.) The empty class []
1745            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1746            The negative empty class [^] matches any one character, independently
1747            of the DOTALL setting.
1749    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1750        non-existent subpattern following a character class starting with ']' and
1751        containing () gave an internal compiling error instead of "reference to
1752        non-existent subpattern". Fortunately, when the pattern did exist, the
1753        compiled code was correct. (When scanning forwards to check for the
1754        existencd of the subpattern, it was treating the data ']' as terminating
1755        the class, so got the count wrong. When actually compiling, the reference
1756        was subsequently set up correctly.)
1758    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1759        it was being rejected as not supported by pcre_dfa_exec(), even though
1760        other assertions are supported. I have made pcre_dfa_exec() support
1761        (*FAIL).
1763    16. The implementation of 13c above involved the invention of a new opcode,
1764        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1765        cannot be changed at match time, I realized I could make a small
1766        improvement to matching performance by compiling OP_ALLANY instead of
1767        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1768        on the OP_ANY path.
1770    17. Compiling pcretest on Windows with readline support failed without the
1771        following two fixes: (1) Make the unistd.h include conditional on
1772        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1774    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1775        ncurses library to be included for pcretest when ReadLine support is
1776        requested, but also to allow for it to be overridden. This patch came from
1777        Daniel Bergström.
1779    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1780        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1781        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1782        spotting this.
1785    Version 7.6 28-Jan-08
1786    ---------------------
1788    1.  A character class containing a very large number of characters with
1789        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1790        overflow.
1792    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1793        HAVE_LONG_LONG is not defined.
1795    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1796        bring them up to date and include new features. This patch includes:
1798        - Fixed PH's badly added libz and libbz2 support.
1799        - Fixed a problem with static linking.
1800        - Added pcredemo. [But later removed - see 7 below.]
1801        - Fixed dftables problem and added an option.
1802        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1803            HAVE_LONG_LONG.
1804        - Added readline support for pcretest.
1805        - Added an listing of the option settings after cmake has run.
1807    4.  A user submitted a patch to Makefile that makes it easy to create
1808        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1809        Makefile.am that cause it to include this special target, without
1810        affecting anything else. Note that the same mingw target plus all
1811        the other distribution libraries and programs are now supported
1812        when configuring with CMake (see 6 below) instead of with
1813        Configure/Make.
1815    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1816        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1817        exported in the Windows port". It has not yet been confirmed that the patch
1818        solves the problem, but it does no harm.
1820    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1821        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1822        with CMake, and also correct the comment about stack recursion.
1824    7.  Remove the automatic building of pcredemo from the ./configure system and
1825        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1826        of a program that users should build themselves after PCRE is installed, so
1827        building it automatically is not really right. What is more, it gave
1828        trouble in some build environments.
1830    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1833    Version 7.5 10-Jan-08
1834    ---------------------
1836    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1837        values in parens when parsing an RE using the C++ wrapper."
1839    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1840        Characters greater than 255 were excluded from the class instead of being
1841        included.
1843    3.  The same bug as (2) above applied to negated POSIX classes such as
1844        [:^space:].
1846    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1847        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1848        I have changed it.
1850    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1851        first named subpattern) and a construct such as (?&a) would reference the
1852        first named subpattern whose name started with "a" (in other words, the
1853        length check was missing). Both these problems are fixed. "Subpattern name
1854        expected" is now given for (?&) (a zero-length name), and this patch also
1855        makes it give the same error for \k'' (previously it complained that that
1856        was a reference to a non-existent subpattern).
1858    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1859        this is right because (?- can be followed by option settings as well as by
1860        digits. I have, however, made the messages clearer.
1862    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1863        than the number used in the conditional) now cause a compile-time error.
1864        This is actually not compatible with Perl, which accepts such patterns, but
1865        treats the conditional as always being FALSE (as PCRE used to), but it
1866        seems to me that giving a diagnostic is better.
1868    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1869        and messages.
1871    9.  Fix two occurrences of "backslash" in comments that should have been
1872        "backspace".
1874    10. Remove two redundant lines of code that can never be obeyed (their function
1875        was moved elsewhere).
1877    11. The program that makes PCRE's Unicode character property table had a bug
1878        which caused it to generate incorrect table entries for sequences of
1879        characters that have the same character type, but are in different scripts.
1880        It amalgamated them into a single range, with the script of the first of
1881        them. In other words, some characters were in the wrong script. There were
1882        thirteen such cases, affecting characters in the following ranges:
1884          U+002b0 - U+002c1
1885          U+0060c - U+0060d
1886          U+0061e - U+00612
1887          U+0064b - U+0065e
1888          U+0074d - U+0076d
1889          U+01800 - U+01805
1890          U+01d00 - U+01d77
1891          U+01d9b - U+01dbf
1892          U+0200b - U+0200f
1893          U+030fc - U+030fe
1894          U+03260 - U+0327f
1895          U+0fb46 - U+0fbb1
1896          U+10450 - U+1049d
1898    12. The -o option (show only the matching part of a line) for pcregrep was not
1899        compatible with GNU grep in that, if there was more than one match in a
1900        line, it showed only the first of them. It now behaves in the same way as
1901        GNU grep.
1903    13. If the -o and -v options were combined for pcregrep, it printed a blank
1904        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1905        does the same. The return code can be used to tell if there were any
1906        non-matching lines.
1908    14. Added --file-offsets and --line-offsets to pcregrep.
1910    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1911        infinitely looping recursion. The bug was that positive lookaheads were not
1912        being skipped when checking for a possible empty match (negative lookaheads
1913        and both kinds of lookbehind were skipped).
1915    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1916        inclusion of <windows.h> to before rather than after the definition of
1917        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1919    17. Specifying a possessive quantifier with a specific limit for a Unicode
1920        character property caused pcre_compile() to compile bad code, which led at
1921        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1922        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1923        caused the error; without that there was no problem.
1925    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1927    19. Added --enable-pcretest-libreadline.
1929    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1930        RE::GlobalReplace(). As a result, the number of replacements returned was
1931        double what it should be. I removed one of the increments, but Craig sent a
1932        later patch that removed the other one (the right fix) and added unit tests
1933        that check the return values (which was not done before).
1935    21. Several CMake things:
1937        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1938            the names libpcre and libpcreposix, not just pcre and pcreposix.
1940        (2) The above change means that pcretest and pcregrep are now correctly
1941            linked with the newly-built libraries, not previously installed ones.
1945    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1946        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1947        UTF-8 newline character). The key issue is that the pattern starts .*;
1948        this means that the match must be either at the beginning, or after a
1949        newline. The bug was in the code for advancing after a failed match and
1950        checking that the new position followed a newline. It was not taking
1951        account of UTF-8 characters correctly.
1953    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1954        character classes. PCRE was not treating the sequence [:...:] as a
1955        character class unless the ... were all letters. Perl, however, seems to
1956        allow any characters between [: and :], though of course it rejects as
1957        unknown any "names" that contain non-letters, because all the known class
1958        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1959        for example, whereas PCRE did not - it did not recognize a POSIX character
1960        class. This seemed a bit dangerous, so the code has been changed to be
1961        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1962        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1963        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1964        Perl does, and where it didn't before.
1966    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1967        Windows environments %n is disabled by default.
1970    Version 7.4 21-Sep-07
1971    ---------------------
1973    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1974        means that a class such as [\s] counted as "explicit reference to CR or
1975        LF". That isn't really right - the whole point of the change was to try to
1976        help when there was an actual mention of one of the two characters. So now
1977        the change happens only if \r or \n (or a literal CR or LF) character is
1978        encountered.
1980    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1981        of both had grown to the point where there were only 3 bits left.
1982        Fortunately, there was spare space in the data structure, and so I have
1983        moved the internal flags into a new 16-bit field to free up more option
1984        bits.
1986    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1987        but did not set the internal JCHANGED flag - either of these is enough to
1988        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1989        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1990        start sets both bits.
1992    4.  Added options (at build time, compile time, exec time) to change \R from
1993        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1995    5.  doc/pcresyntax.html was missing from the distribution.
1997    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1998        compatibility, even though it is no longer used.
2000    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
2001        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
2002        windows.h file is present (where different names are used). [This was
2003        reversed later after testing - see 16 below.]
2005    8.  Changed all #include <config.h> to #include "config.h". There were also
2006        some further <pcre.h> cases that I changed to "pcre.h".
2008    9.  When pcregrep was used with the --colour option, it missed the line ending
2009        sequence off the lines that it output.
2011    10. It was pointed out to me that arrays of string pointers cause lots of
2012        relocations when a shared library is dynamically loaded. A technique of
2013        using a single long string with a table of offsets can drastically reduce
2014        these. I have refactored PCRE in four places to do this. The result is
2015        dramatic:
2017          Originally:                          290
2018          After changing UCP table:            187
2019          After changing error message table:   43
2020          After changing table of "verbs"       36
2021          After changing table of Posix names   22
2023        Thanks to the folks working on Gregex for glib for this insight.
2025    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
2026        unicode-properties was also set.
2028    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
2030    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
2031        checked only for CRLF.
2033    14. Added casts to pcretest.c to avoid compiler warnings.
2035    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
2037    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
2038        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
2039        entirely. This removes changes made in 7 above.
2041    17. The CMake files have been updated, and there is now more information about
2042        building with CMake in the NON-UNIX-USE document.
2045    Version 7.3 28-Aug-07
2046    ---------------------
2048     1. In the rejigging of the build system that eventually resulted in 7.1, the
2049        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
2050        brackets there is not right, since it causes compilers to look for an
2051        installed pcre.h, not the version that is in the source that is being
2052        compiled (which of course may be different). I have changed it back to:
2054          #include "pcre.h"
2056        I have a vague recollection that the change was concerned with compiling in
2057        different directories, but in the new build system, that is taken care of
2058        by the VPATH setting the Makefile.
2060     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
2061        when the subject happened to end in the byte 0x85 (e.g. if the last
2062        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
2063        characters but of course it shouldn't be taken as a newline when it is part
2064        of another character. The bug was that, for an unlimited repeat of . in
2065        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
2066        characters when looking for a newline.
2068     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
2070     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
2071        in debug output.
2073     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
2074        long printing in the pcrecpp unittest when running under MinGW.
2076     6. ESC_K was left out of the EBCDIC table.
2078     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
2079        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
2080        limit also applies to "virtual nesting" when a pattern is recursive, and in
2081        this case 1000 isn't so big. I have been able to remove this limit at the
2082        expense of backing off one optimization in certain circumstances. Normally,
2083        when pcre_exec() would call its internal match() function recursively and
2084        immediately return the result unconditionally, it uses a "tail recursion"
2085        feature to save stack. However, when a subpattern that can match an empty
2086        string has an unlimited repetition quantifier, it no longer makes this
2087        optimization. That gives it a stack frame in which to save the data for
2088        checking that an empty string has been matched. Previously this was taken
2089        from the 1000-entry workspace that had been reserved. So now there is no
2090        explicit limit, but more stack is used.
2092     8. Applied Daniel's patches to solve problems with the import/export magic
2093        syntax that is required for Windows, and which was going wrong for the
2094        pcreposix and pcrecpp parts of the library. These were overlooked when this
2095        problem was solved for the main library.
2097     9. There were some crude static tests to avoid integer overflow when computing
2098        the size of patterns that contain repeated groups with explicit upper
2099        limits. As the maximum quantifier is 65535, the maximum group length was
2100        set at 30,000 so that the product of these two numbers did not overflow a
2101        32-bit integer. However, it turns out that people want to use groups that
2102        are longer than 30,000 bytes (though not repeat them that many times).
2103        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
2104        made it possible to implement the integer overflow checks in a much more
2105        dynamic way, which I have now done. The artificial limitation on group
2106        length has been removed - we now have only the limit on the total length of
2107        the compiled pattern, which depends on the LINK_SIZE setting.
2109    10. Fixed a bug in the documentation for get/copy named substring when
2110        duplicate names are permitted. If none of the named substrings are set, the
2111        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
2112        empty string.
2114    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
2115        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
2116        because the ] is interpreted as the first data character and the
2117        terminating ] is not found. PCRE has been made compatible with Perl in this
2118        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
2119        cause memory overwriting.
2121    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
2122        string has been matched (to stop an infinite loop). It was not recognizing
2123        a conditional subpattern that could match an empty string if that
2124        subpattern was within another subpattern. For example, it looped when
2125        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
2126        condition was not nested. This bug has been fixed.
2128    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
2129        past the start of the subject in the presence of bytes with the top bit
2130        set, for example "\x8aBCD".
2132    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
2133        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
2135    14. Optimized (?!) to (*FAIL).
2137    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
2138        This restricts code points to be within the range 0 to 0x10FFFF, excluding
2139        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
2140        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
2141        does: it's just the validity check that is more restrictive.
2143    16. Inserted checks for integer overflows during escape sequence (backslash)
2144        processing, and also fixed erroneous offset values for syntax errors during
2145        backslash processing.
2147    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
2148        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
2150    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
2151        caused an overrun.
2153    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
2154        something other than just ASCII characters) inside a group that had an
2155        unlimited repeat caused a loop at compile time (while checking to see
2156        whether the group could match an empty string).
2158    20. Debugging a pattern containing \p or \P could cause a crash. For example,
2159        [\P{Any}] did so. (Error in the code for printing property names.)
2161    21. An orphan \E inside a character class could cause a crash.
2163    22. A repeated capturing bracket such as (A)? could cause a wild memory
2164        reference during compilation.
2166    23. There are several functions in pcre_compile() that scan along a compiled
2167        expression for various reasons (e.g. to see if it's fixed length for look
2168        behind). There were bugs in these functions when a repeated \p or \P was
2169        present in the pattern. These operators have additional parameters compared
2170        with \d, etc, and these were not being taken into account when moving along
2171        the compiled data. Specifically:
2173        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
2174            length.
2176        (b) An item such as \pL+ within a repeated group could cause crashes or
2177            loops.
2179        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
2180            "reference to non-existent subpattern" error.
2182        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
2184    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
2185        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
2187    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
2189    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
2190        character were causing crashes (broken optimization).
2192    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
2193        \p or \P) caused a compile-time loop.
2195    28. More problems have arisen in unanchored patterns when CRLF is a valid line
2196        break. For example, the unstudied pattern [\r\n]A does not match the string
2197        "\r\nA" because change 7.0/46 below moves the current point on by two
2198        characters after failing to match at the start. However, the pattern \nA
2199        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
2200        the same is true. There doesn't seem any very clean way out of this, but
2201        what I have chosen to do makes the common cases work: PCRE now takes note
2202        of whether there can be an explicit match for \r or \n anywhere in the
2203        pattern, and if so, 7.0/46 no longer applies. As part of this change,
2204        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
2205        pattern has explicit CR or LF references.
2207    29. Added (*CR) etc for changing newline setting at start of pattern.
2210    Version 7.2 19-Jun-07
2211    ---------------------
2213     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
2214        which is apparently normally available under Windows.
2216     2. Re-jig the pcregrep tests with different newline settings in an attempt
2217        to make them independent of the local environment's newline setting.
2219     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
2221     4. Some of the "internals" tests were previously cut out when the link size
2222        was not 2, because the output contained actual offsets. The recent new
2223        "Z" feature of pcretest means that these can be cut out, making the tests
2224        usable with all link sizes.
2226     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
2227        stack recursion. This gives a massive performance boost under BSD, but just
2228        a small improvement under Linux. However, it saves one field in the frame
2229        in all cases.
2231     6. Added more features from the forthcoming Perl 5.10:
2233        (a) (?-n) (where n is a string of digits) is a relative subroutine or
2234            recursion call. It refers to the nth most recently opened parentheses.
2236        (b) (?+n) is also a relative subroutine call; it refers to the nth next
2237            to be opened parentheses.
2239        (c) Conditions that refer to capturing parentheses can be specified
2240            relatively, for example, (?(-2)... or (?(+3)...
2242        (d) \K resets the start of the current match so that everything before
2243            is not part of it.
2245        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
2247        (f) \g{name} is another synonym - part of Perl 5.10's unification of
2248            reference syntax.
2250        (g) (?| introduces a group in which the numbering of parentheses in each
2251            alternative starts with the same number.
2253        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
2255     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
2258     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
2259        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
2260        for detecting groups that can match an empty string.
2262     9. A pattern with a very large number of alternatives (more than several
2263        hundred) was running out of internal workspace during the pre-compile
2264        phase, where pcre_compile() figures out how much memory will be needed. A
2265        bit of new cunning has reduced the workspace needed for groups with
2266        alternatives. The 1000-alternative test pattern now uses 12 bytes of
2267        workspace instead of running out of the 4096 that are available.
2269    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
2271    11. Applied patch from Google to remove an optimization that didn't quite work.
2272        The report of the bug said:
2274          pcrecpp::RE("a*").FullMatch("aaa") matches, while
2275          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
2276          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
2278    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
2279        it matched the wrong number of bytes.
2282    Version 7.1 24-Apr-07
2283    ---------------------
2285     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
2286        that is more "standard", making use of automake and other Autotools. There
2287        is some re-arrangement of the files and adjustment of comments consequent
2288        on this.
2290     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
2291        for recursive directory scanning broke on some systems because the files
2292        are not scanned in any specific order and on different systems the order
2293        was different. A call to "sort" has been inserted into RunGrepTest for the
2294        approprate test as a short-term fix. In the longer term there may be an
2295        alternative.
2297     3. I had an email from Eric Raymond about problems translating some of PCRE's
2298        man pages to HTML (despite the fact that I distribute HTML pages, some
2299        people do their own conversions for various reasons). The problems
2300        concerned the use of low-level troff macros .br and .in. I have therefore
2301        removed all such uses from the man pages (some were redundant, some could
2302        be replaced by .nf/.fi pairs). The 132html script that I use to generate
2303        HTML has been updated to handle .nf/.fi and to complain if it encounters
2304        .br or .in.
2306     4. Updated comments in configure.ac that get placed in config.h.in and also
2307        arranged for config.h to be included in the distribution, with the name
2308        config.h.generic, for the benefit of those who have to compile without
2309        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
2311     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
2312        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
2313        makevp.bat for the current PCRE, using the additional files
2314        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
2316     6. A Windows user reported a minor discrepancy with test 2, which turned out
2317        to be caused by a trailing space on an input line that had got lost in his
2318        copy. The trailing space was an accident, so I've just removed it.
2320     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
2321        that is needed.
2323     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
2324        as "const" (a) because they are and (b) because it helps the PHP
2325        maintainers who have recently made a script to detect big data structures
2326        in the php code that should be moved to the .rodata section. I remembered
2327        to update Builducptable as well, so it won't revert if ucptable.h is ever
2328        re-created.
2330     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
2331        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
2332        order to be able to cut out the UTF-8 tables in the latter when UTF-8
2333        support is not required. This saves 1.5-2K of code, which is important in
2334        some applications.
2336        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
2337        so as not to refer to the tables, even though these functions will never be
2338        called when UTF-8 support is disabled. Otherwise there are problems with a
2339        shared library.
2341    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
2343        (a) It was defining its arguments as char * instead of void *.
2345        (b) It was assuming that all moves were upwards in memory; this was true
2346            a long time ago when I wrote it, but is no longer the case.
2348        The emulated memove() is provided for those environments that have neither
2349        memmove() nor bcopy(). I didn't think anyone used it these days, but that
2350        is clearly not the case, as these two bugs were recently reported.
2352    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
2353        and Detrail to create the HTML documentation, the .txt form of the man
2354        pages, and it removes trailing spaces from listed files. It also creates
2355        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
2356        case, it wraps all the #defines with #ifndefs. This script should be run
2357        before "make dist".
2359    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
2360        with Unicode property support.
2362        (a) For a maximizing quantifier, if the two different cases of the
2363            character were of different lengths in their UTF-8 codings (there are
2364            some cases like this - I found 11), and the matching function had to
2365            back up over a mixture of the two cases, it incorrectly assumed they
2366            were both the same length.
2368        (b) When PCRE was configured to use the heap rather than the stack for
2369            recursion during matching, it was not correctly preserving the data for
2370            the other case of a UTF-8 character when checking ahead for a match
2371            while processing a minimizing repeat. If the check also involved
2372            matching a wide character, but failed, corruption could cause an
2373            erroneous result when trying to check for a repeat of the original
2374            character.
2376    13. Some tidying changes to the testing mechanism:
2378        (a) The RunTest script now detects the internal link size and whether there
2379            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
2380            values substituted by "configure". (The RunGrepTest script already did
2381            this for UTF-8.) The configure.ac script no longer substitutes the
2382            relevant variables.
2384        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2385            with length and offset values. This means that the output is different
2386            for different internal link sizes. Test 2 is skipped for link sizes
2387            other than 2 because of this, bypassing the problem. Unfortunately,
2388            there was also a test in test 3 (the locale tests) that used /B and
2389            failed for link sizes other than 2. Rather than cut the whole test out,
2390            I have added a new /Z option to pcretest that replaces the length and
2391            offset values with spaces. This is now used to make test 3 independent
2392            of link size. (Test 2 will be tidied up later.)
2394    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2395        segmentation fault instead of returning the appropriate error message.
2397    15. In multiline mode when the newline sequence was set to "any", the pattern
2398        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2399        This doesn't seem right; it now treats the CRLF combination as the line
2400        ending, and so does not match in that case. It's only a pattern such as ^$
2401        that would hit this one: something like ^ABC$ would have failed after \r
2402        and then tried again after \r\n.
2404    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2405        in an attempt to make files that differ only in their line terminators
2406        compare equal. This works on Linux.
2408    17. Under certain error circumstances pcregrep might try to free random memory
2409        as it exited. This is now fixed, thanks to valgrind.
2411    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2412        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2413        was because its rules for how to advance for /g after matching an empty
2414        string at the end of a line did not allow for this case. They now check for
2415        it specially.
2417    20. pcretest is supposed to handle patterns and data of any length, by
2418        extending its buffers when necessary. It was getting this wrong when the
2419        buffer for a data line had to be extended.
2421    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2422        CRLF as a newline sequence.
2424    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2425        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2426        I have nevertheless tidied it up.
2428    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2430    24. Added a man page for pcre-config.
2433    Version 7.0 19-Dec-06
2434    ---------------------
2436     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2437        moving to gcc 4.1.1.
2439     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2440        sys/time.h, which is documented as needed for this function. It doesn't
2441        seem to matter on Linux, but it showed up on some releases of OS X.
2443     3. It seems that there are systems where bytes whose values are greater than
2444        127 match isprint() in the "C" locale. The "C" locale should be the
2445        default when a C program starts up. In most systems, only ASCII printing
2446        characters match isprint(). This difference caused the output from pcretest
2447        to vary, making some of the tests fail. I have changed pcretest so that:
2449        (a) When it is outputting text in the compiled version of a pattern, bytes
2450            other than 32-126 are always shown as hex escapes.
2452        (b) When it is outputting text that is a matched part of a subject string,
2453            it does the same, unless a different locale has been set for the match
2454            (using the /L modifier). In this case, it uses isprint() to decide.
2456     4. Fixed a major bug that caused incorrect computation of the amount of memory
2457        required for a compiled pattern when options that changed within the
2458        pattern affected the logic of the preliminary scan that determines the
2459        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2460        that the computed length was too small. The symptoms of this bug were
2461        either the PCRE error "internal error: code overflow" from pcre_compile(),
2462        or a glibc crash with a message such as "pcretest: free(): invalid next
2463        size (fast)". Examples of patterns that provoked this bug (shown in
2464        pcretest format) are:
2466          /(?-x: )/x
2467          /(?x)(?-x: \s*#\s*)/
2468          /((?i)[\x{c0}])/8
2469          /(?i:[\x{c0}])/8
2471        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2472        is now done differently.
2474     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2475        wrapper classes; (b) implement a new function in the C++ scanner that is
2476        more efficient than the old way of doing things because it avoids levels of
2477        recursion in the regex matching; (c) add a paragraph to the documentation
2478        for the FullMatch() function.
2480     6. The escape sequence \n was being treated as whatever was defined as
2481        "newline". Not only was this contrary to the documentation, which states
2482        that \n is character 10 (hex 0A), but it also went horribly wrong when
2483        "newline" was defined as CRLF. This has been fixed.
2485     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2486        was being set to -1 for the "end of line" case (supposedly a value that no
2487        character can have). Though this value is never used (the check for end of
2488        line is "zero bytes in current character"), it caused compiler complaints.
2489        I've changed it to 0xffffffff.
2491     8. In pcre_version.c, the version string was being built by a sequence of
2492        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2493        string (as it is for production releases) called a macro with an empty
2494        argument. The C standard says the result of this is undefined. The gcc
2495        compiler treats it as an empty string (which was what was wanted) but it is
2496        reported that Visual C gives an error. The source has been hacked around to
2497        avoid this problem.
2499     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2500        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2501        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2502        of them did).
2504    10. Originally, pcretest opened its input and output without "b"; then I was
2505        told that "b" was needed in some environments, so it was added for release
2506        5.0 to both the input and output. (It makes no difference on Unix-like
2507        systems.) Later I was told that it is wrong for the input on Windows. I've
2508        now abstracted the modes into two macros, to make it easier to fiddle with
2509        them, and removed "b" from the input mode under Windows.
2511    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2513    12. Added -help and --help to pcretest as an official way of being reminded
2514        of the options.
2516    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2517        and pcrecpp.cc because they annoy compilers at high warning levels.
2519    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2521    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2522        scripts are not C programs :-) and which was not noticed because it works
2523        on Linux.
2525    16. pcretest is supposed to handle any length of pattern and data line (as one
2526        line or as a continued sequence of lines) by extending its input buffer if
2527        necessary. This feature was broken for very long pattern lines, leading to
2528        a string of junk being passed to pcre_compile() if the pattern was longer
2529        than about 50K.
2531    17. I have done a major re-factoring of the way pcre_compile() computes the
2532        amount of memory needed for a compiled pattern. Previously, there was code
2533        that made a preliminary scan of the pattern in order to do this. That was
2534        OK when PCRE was new, but as the facilities have expanded, it has become
2535        harder and harder to keep it in step with the real compile phase, and there
2536        have been a number of bugs (see for example, 4 above). I have now found a
2537        cunning way of running the real compile function in a "fake" mode that
2538        enables it to compute how much memory it would need, while actually only
2539        ever using a few hundred bytes of working memory and without too many
2540        tests of the mode. This should make future maintenance and development
2541        easier. A side effect of this work is that the limit of 200 on the nesting
2542        depth of parentheses has been removed (though this was never a serious
2543        limitation, I suspect). However, there is a downside: pcre_compile() now
2544        runs more slowly than before (30% or more, depending on the pattern). I
2545        hope this isn't a big issue. There is no effect on runtime performance.
2547    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2548        newline (only possible for the last line of a file) and it was a
2549        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2551    19. Added additional timing features to pcretest. (1) The -tm option now times
2552        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2553        separate command line item, by a number that specifies the number of
2554        repeats to use when timing. The default is 50000; this gives better
2555        precision, but takes uncomfortably long for very large patterns.
2557    20. Extended pcre_study() to be more clever in cases where a branch of a
2558        subpattern has no definite first character. For example, (a*|b*)[cd] would
2559        previously give no result from pcre_study(). Now it recognizes that the
2560        first character must be a, b, c, or d.
2562    21. There was an incorrect error "recursive call could loop indefinitely" if
2563        a subpattern (or the entire pattern) that was being tested for matching an
2564        empty string contained only one non-empty item after a nested subpattern.
2565        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2566        incorrectly, because the \d was being skipped in the check.
2568    22. The pcretest program now has a new pattern option /B and a command line
2569        option -b, which is equivalent to adding /B to every pattern. This causes
2570        it to show the compiled bytecode, without the additional information that
2571        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2572        is the same as /B/I).
2574    23. A new optimization is now able automatically to treat some sequences such
2575        as a*b as a*+b. More specifically, if something simple (such as a character
2576        or a simple class like \d) has an unlimited quantifier, and is followed by
2577        something that cannot possibly match the quantified thing, the quantifier
2578        is automatically "possessified".
2580    24. A recursive reference to a subpattern whose number was greater than 39
2581        went wrong under certain circumstances in UTF-8 mode. This bug could also
2582        have affected the operation of pcre_study().
2584    25. Realized that a little bit of performance could be had by replacing
2585        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2587    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2589    27. Possessive quantifiers such as a++ were previously implemented by turning
2590        them into atomic groups such as ($>a+). Now they have their own opcodes,
2591        which improves performance. This includes the automatically created ones
2592        from 23 above.
2594    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2595        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2596        the first matched character to be a colon. This applied both to named and
2597        numbered groups.
2599    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2601    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2602        building PCRE on Windows easier, so I have included it in the distribution.
2604    31. There is now a check in pcretest against a ridiculously large number being
2605        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2606        loop, the loop is abandoned.
2608    32. Forward references to subpatterns in conditions such as (?(2)...) where
2609        subpattern 2 is defined later cause pcre_compile() to search forwards in
2610        the pattern for the relevant set of parentheses. This search went wrong
2611        when there were unescaped parentheses in a character class, parentheses
2612        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2614    33. "Subroutine" calls and backreferences were previously restricted to
2615        referencing subpatterns earlier in the regex. This restriction has now
2616        been removed.
2618    34. Added a number of extra features that are going to be in Perl 5.10. On the
2619        whole, these are just syntactic alternatives for features that PCRE had
2620        previously implemented using the Python syntax or my own invention. The
2621        other formats are all retained for compatibility.
2623        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2624            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2625            also .NET compatible.
2627        (b) A recursion or subroutine call to a named group can now be defined as
2628            (?&name) as well as (?P>name).
2630        (c) A backreference to a named group can now be defined as \k<name> or
2631            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2632            5.10, are also .NET compatible.
2634        (d) A conditional reference to a named group can now use the syntax
2635            (?(<name>) or (?('name') as well as (?(name).
2637        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2638            groups (named and numbered) that are never evaluated inline, but can be
2639            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2640            is always false. There may be only one alternative in such a group.
2642        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2643            as the simple (?(R). The condition is true only if the most recent
2644            recursion is that of the given number or name. It does not search out
2645            through the entire recursion stack.
2647        (g) The escape \gN or \g{N} has been added, where N is a positive or
2648            negative number, specifying an absolute or relative reference.
2650    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2651        some "unreachable code" warnings.
2653    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2654        things, this adds five new scripts.
2656    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2657        There were also incompatibilities regarding the handling of \Q..\E inside
2658        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2659        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2661    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2662        matches an empty string, and forcibly breaks the loop. There were bugs in
2663        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2664        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2665        separate and independent bugs (that affected different cases) have been
2666        fixed.
2668    39. Refactored the code to abolish the use of different opcodes for small
2669        capturing bracket numbers. This is a tidy that I avoided doing when I
2670        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2671        The new approach is not only tidier, it makes it possible to reduce the
2672        memory needed to fix the previous bug (38).
2674    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2675        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2676        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2677        mode.
2679    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2680        report.
2682    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2683        copy construction and assignment in the C++ wrapper.
2685    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2686        couple of bugs that could have given wrong results in the "--newline=crlf"
2687        case.
2689    44. Added a number of casts and did some reorganization of signed/unsigned int
2690        variables following suggestions from Dair Grant. Also renamed the variable
2691        "this" as "item" because it is a C++ keyword.
2693    45. Arranged for dftables to add
2695          #include "pcre_internal.h"
2697        to pcre_chartables.c because without it, gcc 4.x may remove the array
2698        definition from the final binary if PCRE is built into a static library and
2699        dead code stripping is activated.
2701    46. For an unanchored pattern, if a match attempt fails at the start of a
2702        newline sequence, and the newline setting is CRLF or ANY, and the next two
2703        characters are CRLF, advance by two characters instead of one.
2706    Version 6.7 04-Jul-06
2707    ---------------------
2709     1. In order to handle tests when input lines are enormously long, pcretest has
2710        been re-factored so that it automatically extends its buffers when
2711        necessary. The code is crude, but this _is_ just a test program. The
2712        default size has been increased from 32K to 50K.
2714     2. The code in pcre_study() was using the value of the re argument before
2715        testing it for NULL. (Of course, in any sensible call of the function, it
2716        won't be NULL.)
2718     3. The memmove() emulation function in pcre_internal.h, which is used on
2719        systems that lack both memmove() and bcopy() - that is, hardly ever -
2720        was missing a "static" storage class specifier.
2722     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2723        containing an extended class (one that cannot be represented by a bitmap
2724        because it contains high-valued characters or Unicode property items, e.g.
2725        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2726        pattern, but PCRE should not loop if you do not (it no longer does).
2727        [Detail: two cases were found: (a) a repeated subpattern containing an
2728        extended class; (b) a recursive reference to a subpattern that followed a
2729        previous extended class. It wasn't skipping over the extended class
2730        correctly when UTF-8 mode was not set.]
2732     5. A negated single-character class was not being recognized as fixed-length
2733        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2734        compile error "lookbehind assertion is not fixed length".
2736     6. The RunPerlTest auxiliary script was showing an unexpected difference
2737        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2738        write a Perl script that can interpret lines of an input file either as
2739        byte characters or as UTF-8, which is what "perltest" was being required to
2740        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2741        can't do is switch easily at run time between having the "use utf8;" pragma
2742        or not. In the end, I fudged it by using the RunPerlTest script to insert
2743        "use utf8;" explicitly for the UTF-8 tests.
2745     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2746        the end of the subject string, contrary to the documentation and to what
2747        Perl does. This was true of both matching functions. Now it matches only at
2748        the start of the subject and immediately after *internal* newlines.
2750     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2751        a pointer to an int instead of a pointer to an unsigned long int. This
2752        caused problems on 64-bit systems.
2754     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2755        instance of the 'standard' template library not being so standard".
2757    10. There was no check on the number of named subpatterns nor the maximum
2758        length of a subpattern name. The product of these values is used to compute
2759        the size of the memory block for a compiled pattern. By supplying a very
2760        long subpattern name and a large number of named subpatterns, the size
2761        computation could be caused to overflow. This is now prevented by limiting
2762        the length of names to 32 characters, and the number of named subpatterns
2763        to 10,000.
2765    11. Subpatterns that are repeated with specific counts have to be replicated in
2766        the compiled pattern. The size of memory for this was computed from the
2767        length of the subpattern and the repeat count. The latter is limited to
2768        65535, but there was no limit on the former, meaning that integer overflow
2769        could in principle occur. The compiled length of a repeated subpattern is
2770        now limited to 30,000 bytes in order to prevent this.
2772    12. Added the optional facility to have named substrings with the same name.
2774    13. Added the ability to use a named substring as a condition, using the
2775        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2776        are numbers (not recommended). Forward references are permitted.
2778    14. Added forward references in named backreferences (if you see what I mean).
2780    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2781        pattern could run off the end of the subject. For example, the pattern
2782        "(?s)(.{1,5})"8 did this with the subject "ab".
2784    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2785        PCRE_CASELESS was set when matching characters that were quantified with ?
2786        or *.
2788    17. A character class other than a single negated character that had a minimum
2789        but no maximum quantifier - for example [ab]{6,} - was not handled
2790        correctly by pce_dfa_exec(). It would match only one character.
2792    18. A valid (though odd) pattern that looked like a POSIX character
2793        class but used an invalid character after [ (for example [[,abc,]]) caused
2794        pcre_compile() to give the error "Failed: internal error: code overflow" or
2795        in some cases to crash with a glibc free() error. This could even happen if
2796        the pattern terminated after [[ but there just happened to be a sequence of
2797        letters, a binary zero, and a closing ] in the memory that followed.
2799    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2800        over the years. Originally (before any Unicode support), just the bottom 8
2801        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2802        output from "man perlunicode" includes this:
2804          The regular expression compiler produces polymorphic opcodes.  That
2805          is, the pattern adapts to the data and automatically switches to
2806          the Unicode character scheme when presented with Unicode data--or
2807          instead uses a traditional byte scheme when presented with byte
2808          data.
2810        Sadly, a wide octal escape does not cause a switch, and in a string with
2811        no other multibyte characters, these octal escapes are treated as before.
2812        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2813        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2814        Unicode string.
2816        I have not perpetrated such confusion in PCRE. Up till now, it took just
2817        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2818        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2819        translate to the appropriate multibyte character.
2821    29. Applied some refactoring to reduce the number of warnings from Microsoft
2822        and Borland compilers. This has included removing the fudge introduced
2823        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2824        a warning about an unused variable.
2826    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2827        characters since release 4.0, because Perl (from release 5.004) does not.
2828        [Or at least, is documented not to: some releases seem to be in conflict
2829        with the documentation.] However, when a pattern was studied with
2830        pcre_study() and all its branches started with \s, PCRE still included VT
2831        as a possible starting character. Of course, this did no harm; it just
2832        caused an unnecessary match attempt.
2834    22. Removed a now-redundant internal flag bit that recorded the fact that case
2835        dependency changed within the pattern. This was once needed for "required
2836        byte" processing, but is no longer used. This recovers a now-scarce options
2837        bit. Also moved the least significant internal flag bit to the most-
2838        significant bit of the word, which was not previously used (hangover from
2839        the days when it was an int rather than a uint) to free up another bit for
2840        the future.
2842    23. Added support for CRLF line endings as well as CR and LF. As well as the
2843        default being selectable at build time, it can now be changed at runtime
2844        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2845        specify that it is scanning data with non-default line endings.
2847    24. Changed the definition of CXXLINK to make it agree with the definition of
2848        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2850    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2851        recursions. This makes a big different to stack usage for some patterns.
2853    26. If a subpattern containing a named recursion or subroutine reference such
2854        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2855        the space required for the compiled pattern went wrong and gave too small a
2856        value. Depending on the environment, this could lead to "Failed: internal
2857        error: code overflow at offset 49" or "glibc detected double free or
2858        corruption" errors.
2860    27. Applied patches from Google (a) to support the new newline modes and (b) to
2861        advance over multibyte UTF-8 characters in GlobalReplace.
2863    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2864        difference for some implementation of PCRE in some Windows version.
2866    29. Added some extra testing facilities to pcretest:
2868        \q<number>   in a data line sets the "match limit" value
2869        \Q<number>   in a data line sets the "match recursion limt" value
2870        -S <number>  sets the stack size, where <number> is in megabytes
2872        The -S option isn't available for Windows.
2875    Version 6.6 06-Feb-06
2876    ---------------------
2878     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2879        in pcreposix.h. I have copied the definition from pcre.h.
2881     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2882        because pcre.h is no longer a built file.
2884     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2885        not normally included in the compiled code.
2888    Version 6.5 01-Feb-06
2889    ---------------------
2891     1. When using the partial match feature with pcre_dfa_exec(), it was not
2892        anchoring the second and subsequent partial matches at the new starting
2893        point. This could lead to incorrect results. For example, with the pattern
2894        /1234/, partially matching against "123" and then "a4" gave a match.
2896     2. Changes to pcregrep:
2898        (a) All non-match returns from pcre_exec() were being treated as failures
2899            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2900            error message is output. Some extra information is given for the
2901            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2902            probably the only errors that are likely to be caused by users (by
2903            specifying a regex that has nested indefinite repeats, for instance).
2904            If there are more than 20 of these errors, pcregrep is abandoned.
2906        (b) A binary zero was treated as data while matching, but terminated the
2907            output line if it was written out. This has been fixed: binary zeroes
2908            are now no different to any other data bytes.
2910        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2911            used to set a locale for matching. The --locale=xxxx long option has
2912            been added (no short equivalent) to specify a locale explicitly on the
2913            pcregrep command, overriding the environment variables.
2915        (d) When -B was used with -n, some line numbers in the output were one less
2916            than they should have been.
2918        (e) Added the -o (--only-matching) option.
2920        (f) If -A or -C was used with -c (count only), some lines of context were
2921            accidentally printed for the final match.
2923        (g) Added the -H (--with-filename) option.
2925        (h) The combination of options -rh failed to suppress file names for files
2926            that were found from directory arguments.
2928        (i) Added the -D (--devices) and -d (--directories) options.
2930        (j) Added the -F (--fixed-strings) option.
2932        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2934        (l) Added the --colo(u)r option.
2936        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2937            is not present by default.
2939     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2940        items such as (?R) or (?1), when the recursion could match a number of
2941        alternatives. If it matched one of the alternatives, but subsequently,
2942        outside the recursion, there was a failure, the code tried to back up into
2943        the recursion. However, because of the way PCRE is implemented, this is not
2944        possible, and the result was an incorrect result from the match.
2946        In order to prevent this happening, the specification of recursion has
2947        been changed so that all such subpatterns are automatically treated as
2948        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2950     4. I had overlooked the fact that, in some locales, there are characters for
2951        which isalpha() is true but neither isupper() nor islower() are true. In
2952        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2953        and ordfeminine) are like this. This affected the treatment of \w and \W
2954        when they appeared in character classes, but not when they appeared outside
2955        a character class. The bit map for "word" characters is now created
2956        separately from the results of isalnum() instead of just taking it from the
2957        upper, lower, and digit maps. (Plus the underscore character, of course.)
2959     5. The above bug also affected the handling of POSIX character classes such as
2960        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2961        permanent tables. Instead, the bit maps for such a class were previously
2962        created as the appropriate unions of the upper, lower, and digit bitmaps.
2963        Now they are created by subtraction from the [[:word:]] class, which has
2964        its own bitmap.
2966     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2967        It is created by subtracting the vertical space characters (\x09, \x0a,
2968        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2969        subtraction was done in the overall bitmap for a character class, meaning
2970        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2971        be recognized. This bug has been fixed.
2973     7. Patches from the folks at Google:
2975          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2976          real life, but is still worth protecting against".
2978          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2979          regular expressions".
2981          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2982          have it.
2984          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2985          "configure" and the latter not, in order to fix a problem somebody had
2986          with compiling the Arg class on HP-UX.
2988          (e) Improve the error-handling of the C++ wrapper a little bit.
2990          (f) New tests for checking recursion limiting.
2992     8. The pcre_memmove() function, which is used only if the environment does not
2993        have a standard memmove() function (and is therefore rarely compiled),
2994        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2995        returning a result (though PCRE never actually uses the result).
2997     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2998        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2999        returned instead of calling malloc() with an overflowing number that would
3000        most likely cause subsequent chaos.
3002    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
3004    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
3005        with this option is matched, the nmatch and pmatch options of regexec() are
3006        ignored.
3008    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
3009        provided in case anyone wants to the the POSIX interface with UTF-8
3010        strings.
3012    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
3013        C++ linking (needed for some HP-UX environments).
3015    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
3016        (unused parameter) and in the pcre_printint() function (omitted "default"
3017        switch label when the default is to do nothing).
3019    15. Added some code to make it possible, when PCRE is compiled as a C++
3020        library, to replace subject pointers for pcre_exec() with a smart pointer
3021        class, thus making it possible to process discontinuous strings.
3023    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
3024        much the same function. They were added by different people who were trying
3025        to make PCRE easy to compile on non-Unix systems. It has been suggested
3026        that PCRE_EXPORT be abolished now that there is more automatic apparatus
3027        for compiling on Windows systems. I have therefore replaced it with
3028        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
3029        defaults to "extern" for C or "extern C" for C++, which works fine on
3030        Unix-like systems. It is now possible to override the value of PCRE_DATA_
3031        SCOPE with something explicit in config.h. In addition:
3033        (a) pcreposix.h still had just "extern" instead of either of these macros;
3034            I have replaced it with PCRE_DATA_SCOPE.
3036        (b) Functions such as _pcre_xclass(), which are internal to the library,
3037            but external in the C sense, all had PCRE_EXPORT in their definitions.
3038            This is apparently wrong for the Windows case, so I have removed it.
3039            (It makes no difference on Unix-like systems.)
3041    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
3042        of recursive calls to match(). This is different to MATCH_LIMIT because
3043        that limits the total number of calls to match(), not all of which increase
3044        the depth of recursion. Limiting the recursion depth limits the amount of
3045        stack (or heap if NO_RECURSE is set) that is used. The default can be set
3046        when PCRE is compiled, and changed at run time. A patch from Google adds
3047        this functionality to the C++ interface.
3049    18. Changes to the handling of Unicode character properties:
3051        (a) Updated the table to Unicode 4.1.0.
3053        (b) Recognize characters that are not in the table as "Cn" (undefined).
3055        (c) I revised the way the table is implemented to a much improved format
3056            which includes recognition of ranges. It now supports the ranges that
3057            are defined in UnicodeData.txt, and it also amalgamates other
3058            characters into ranges. This has reduced the number of entries in the
3059            table from around 16,000 to around 3,000, thus reducing its size
3060            considerably. I realized I did not need to use a tree structure after
3061            all - a binary chop search is just as efficient. Having reduced the
3062            number of entries, I extended their size from 6 bytes to 8 bytes to
3063            allow for more data.
3065        (d) Added support for Unicode script names via properties such as \p{Han}.
3067    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
3068        matching that character.
3070    20. When matching a repeated Unicode property with a minimum greater than zero,
3071        (for example \pL{2,}), PCRE could look past the end of the subject if it
3072        reached it while seeking the minimum number of characters. This could
3073        happen only if some of the characters were more than one byte long, because
3074        there is a check for at least the minimum number of bytes.
3076    21. Refactored the implementation of \p and \P so as to be more general, to
3077        allow for more different types of property in future. This has changed the
3078        compiled form incompatibly. Anybody with saved compiled patterns that use
3079        \p or \P will have to recompile them.
3081    22. Added "Any" and "L&" to the supported property types.
3083    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
3084        but give a compile time error if the value is greater than 0xff.
3086    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
3087        accidentally not being installed or uninstalled.
3089    25. The pcre.h file was built from pcre.h.in, but the only changes that were
3090        made were to insert the current release number. This seemed silly, because
3091        it made things harder for people building PCRE on systems that don't run
3092        "configure". I have turned pcre.h into a distributed file, no longer built
3093        by "configure", with the version identification directly included. There is
3094        no longer a pcre.h.in file.
3096        However, this change necessitated a change to the pcre-config script as
3097        well. It is built from pcre-config.in, and one of the substitutions was the
3098        release number. I have updated configure.ac so that ./configure now finds
3099        the release number by grepping pcre.h.
3101    26. Added the ability to run the tests under valgrind.
3104    Version 6.4 05-Sep-05
3105    ---------------------
3107     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
3108        "--" to be printed when multiple files were scanned, even when none of the
3109        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
3110        consider it to be a bug, and have restored the previous behaviour.
3112     2. A couple of code tidies to get rid of compiler warnings.
3114     3. The pcretest program used to cheat by referring to symbols in the library
3115        whose names begin with _pcre_. These are internal symbols that are not
3116        really supposed to be visible externally, and in some environments it is
3117        possible to suppress them. The cheating is now confined to including
3118        certain files from the library's source, which is a bit cleaner.
3120     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
3121        file's purpose clearer.
3123     5. Reorganized pcre_ucp_findchar().
3126    Version 6.3 15-Aug-05
3127    ---------------------
3129     1. The file libpcre.pc.in did not have general read permission in the tarball.
3131     2. There were some problems when building without C++ support:
3133        (a) If C++ support was not built, "make install" and "make test" still
3134            tried to test it.
3136        (b) There were problems when the value of CXX was explicitly set. Some
3137            changes have been made to try to fix these, and ...
3139        (c) --disable-cpp can now be used to explicitly disable C++ support.
3141        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
3142            backslash in a target when C++ was disabled. This confuses some
3143            versions of "make", apparently. Using an intermediate variable solves
3144            this. (Same for CPP_LOBJ.)
3146     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
3147        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
3148        necessary on certain architectures.
3150     4. Added a setting of -export-symbols-regex to the link command to remove
3151        those symbols that are exported in the C sense, but actually are local
3152        within the library, and not documented. Their names all begin with
3153        "_pcre_". This is not a perfect job, because (a) we have to except some
3154        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
3155        available (and never for static libraries). I have made a note to try to
3156        find a way round (a) in the future.
3159    Version 6.2 01-Aug-05
3160    ---------------------
3162     1. There was no test for integer overflow of quantifier values. A construction
3163        such as {1111111111111111} would give undefined results. What is worse, if
3164        a minimum quantifier for a parenthesized subpattern overflowed and became
3165        negative, the calculation of the memory size went wrong. This could have
3166        led to memory overwriting.
3168     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
3170     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
3171        operating environments where this matters.
3173     4. Applied Giuseppe Maxia's patch to add additional features for controlling
3174        PCRE options from within the C++ wrapper.
3176     5. Named capturing subpatterns were not being correctly counted when a pattern
3177        was compiled. This caused two problems: (a) If there were more than 100
3178        such subpatterns, the calculation of the memory needed for the whole
3179        compiled pattern went wrong, leading to an overflow error. (b) Numerical
3180        back references of the form \12, where the number was greater than 9, were
3181        not recognized as back references, even though there were sufficient
3182        previous subpatterns.
3184     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
3185        versions of gcc, e.g. 2.95.4.
3188    Version 6.1 21-Jun-05
3189    ---------------------
3191     1. There was one reference to the variable "posix" in pcretest.c that was not
3192        surrounded by "#if !defined NOPOSIX".
3194     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
3195        the cross-check on the old pcre_info() function, for the benefit of the
3196        cut-down version of PCRE that is currently imported into Exim.
3198     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
3199        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
3200        patterns that start (?i) but I don't think that matters. The use of (?i) is
3201        just an example; this all applies to the other options as well.
3203     4. Since libtool seems to echo the compile commands it is issuing, the output
3204        from "make" can be reduced a bit by putting "@" in front of each libtool
3205        compile command.
3207     5. Patch from the folks at Google for configure.in to be a bit more thorough
3208        in checking for a suitable C++ installation before trying to compile the
3209        C++ stuff. This should fix a reported problem when a compiler was present,
3210        but no suitable headers.
3212     6. The man pages all had just "PCRE" as their title. I have changed them to
3213        be the relevant file name. I have also arranged that these names are
3214        retained in the file doc/pcre.txt, which is a concatenation in text format
3215        of all the man pages except the little individual ones for each function.
3217     7. The NON-UNIX-USE file had not been updated for the different set of source
3218        files that come with release 6. I also added a few comments about the C++
3219        wrapper.
3222    Version 6.0 07-Jun-05
3223    ---------------------
3225     1. Some minor internal re-organization to help with my DFA experiments.
3227     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
3228        didn't matter for the library itself when fully configured, but did matter
3229        when compiling without UCP support, or within Exim, where the ucp files are
3230        not imported.
3232     3. Refactoring of the library code to split up the various functions into
3233        different source modules. The addition of the new DFA matching code (see
3234        below) to a single monolithic source would have made it really too
3235        unwieldy, quite apart from causing all the code to be include in a
3236        statically linked application, when only some functions are used. This is
3237        relevant even without the DFA addition now that patterns can be compiled in
3238        one application and matched in another.
3240        The downside of splitting up is that there have to be some external
3241        functions and data tables that are used internally in different modules of
3242        the library but which are not part of the API. These have all had their
3243        names changed to start with "_pcre_" so that they are unlikely to clash
3244        with other external names.
3246     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
3247        a different (DFA) algorithm. Although it is slower than the original
3248        function, it does have some advantages for certain types of matching
3249        problem.
3251     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
3252        including restarting after a partial match.
3254     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
3255        defined when compiling for Windows was sent to me. I have put it into the
3256        code, though I have no means of testing or verifying it.
3258     7. Added the pcre_refcount() auxiliary function.
3260     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
3261        match before or at the first newline in the subject string. In pcretest,
3262        the /f option on a pattern can be used to set this.
3264     9. A repeated \w when used in UTF-8 mode with characters greater than 256
3265        would behave wrongly. This has been present in PCRE since release 4.0.
3267    10. A number of changes to the pcregrep command:
3269        (a) Refactored how -x works; insert ^(...)$ instead of setting
3270            PCRE_ANCHORED and checking the length, in preparation for adding
3271            something similar for -w.
3273        (b) Added the -w (match as a word) option.
3275        (c) Refactored the way lines are read and buffered so as to have more
3276            than one at a time available.
3278        (d) Implemented a pcregrep test script.
3280        (e) Added the -M (multiline match) option. This allows patterns to match
3281            over several lines of the subject. The buffering ensures that at least
3282            8K, or the rest of the document (whichever is the shorter) is available
3283            for matching (and similarly the previous 8K for lookbehind assertions).
3285        (f) Changed the --help output so that it now says
3287              -w, --word-regex(p)
3289            instead of two lines, one with "regex" and the other with "regexp"
3290            because that confused at least one person since the short forms are the
3291            same. (This required a bit of code, as the output is generated
3292            automatically from a table. It wasn't just a text change.)
3294        (g) -- can be used to terminate pcregrep options if the next thing isn't an
3295            option but starts with a hyphen. Could be a pattern or a path name
3296            starting with a hyphen, for instance.
3298        (h) "-" can be given as a file name to represent stdin.
3300        (i) When file names are being printed, "(standard input)" is used for
3301            the standard input, for compatibility with GNU grep. Previously
3302            "<stdin>" was used.
3304        (j) The option --label=xxx can be used to supply a name to be used for
3305            stdin when file names are being printed. There is no short form.
3307        (k) Re-factored the options decoding logic because we are going to add
3308            two more options that take data. Such options can now be given in four
3309            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
3311        (l) Added the -A, -B, and -C options for requesting that lines of context
3312            around matches be printed.
3314        (m) Added the -L option to print the names of files that do not contain
3315            any matching lines, that is, the complement of -l.
3317        (n) The return code is 2 if any file cannot be opened, but pcregrep does
3318            continue to scan other files.
3320        (o) The -s option was incorrectly implemented. For compatibility with other
3321            greps, it now suppresses the error message for a non-existent or non-
3322            accessible file (but not the return code). There is a new option called
3323            -q that suppresses the output of matching lines, which was what -s was
3324            previously doing.
3326        (p) Added --include and --exclude options to specify files for inclusion
3327            and exclusion when recursing.
3329    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
3330        Hopefully, it now does.
3332    12. Missing cast in pcre_study().
3334    13. Added an "uninstall" target to the makefile.
3336    14. Replaced "extern" in the function prototypes in Makefile.in with
3337        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
3338        world, but is set differently for Windows.
3340    15. Added a second compiling function called pcre_compile2(). The only
3341        difference is that it has an extra argument, which is a pointer to an
3342        integer error code. When there is a compile-time failure, this is set
3343        non-zero, in addition to the error test pointer being set to point to an
3344        error message. The new argument may be NULL if no error number is required
3345        (but then you may as well call pcre_compile(), which is now just a
3346        wrapper). This facility is provided because some applications need a
3347        numeric error indication, but it has also enabled me to tidy up the way
3348        compile-time errors are handled in the POSIX wrapper.
3350    16. Added VPATH=.libs to the makefile; this should help when building with one
3351        prefix path and installing with another. (Or so I'm told by someone who
3352        knows more about this stuff than I do.)
3354    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
3355        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
3356        match everything, including newlines. This is not POSIX-compatible, but
3357        somebody wanted the feature. From pcretest it can be activated by using
3358        both the P and the s flags.
3360    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
3362    19. libpcre.pc was being incorrectly installed as executable.
3364    20. A couple of places in pcretest check for end-of-line by looking for '\n';
3365        it now also looks for '\r' so that it will work unmodified on Windows.
3367    21. Added Google's contributed C++ wrapper to the distribution.
3369    22. Added some untidy missing memory free() calls in pcretest, to keep
3370        Electric Fence happy when testing.
3374    Version 5.0 13-Sep-04
3375    ---------------------
3377     1. Internal change: literal characters are no longer packed up into items
3378        containing multiple characters in a single byte-string. Each character
3379        is now matched using a separate opcode. However, there may be more than one
3380        byte in the character in UTF-8 mode.
3382     2. The pcre_callout_block structure has two new fields: pattern_position and
3383        next_item_length. These contain the offset in the pattern to the next match
3384        item, and its length, respectively.
3386     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
3387        insertion of callouts before each pattern item. Added the /C option to
3388        pcretest to make use of this.
3390     4. On the advice of a Windows user, the lines
3392          #if defined(_WIN32) || defined(WIN32)
3393          _setmode( _fileno( stdout ), 0x8000 );
3394          #endif  /* defined(_WIN32) || defined(WIN32) */
3396        have been added to the source of pcretest. This apparently does useful
3397        magic in relation to line terminators.
3399     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
3400        for the benefit of those environments where the "b" makes a difference.
3402     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
3403        to know about it. I have put a hack into configure.in that adds in code
3404        to set GCC=yes if CC=icc. This seems to end up at a point in the
3405        generated configure script that is early enough to affect the setting of
3406        compiler options, which is what is needed, but I have no means of testing
3407        whether it really works. (The user who reported this had patched the
3408        generated configure script, which of course I cannot do.)
3410        LATER: After change 22 below (new libtool files), the configure script
3411        seems to know about icc (and also ecc). Therefore, I have commented out
3412        this hack in configure.in.
3414     7. Added support for pkg-config (2 patches were sent in).
3416     8. Negated POSIX character classes that used a combination of internal tables
3417        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
3418        [[:^ascii]]. Typically, they would match almost any characters. The other
3419        POSIX classes were not broken in this way.
3421     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
3422        to find the match, as PCRE was deluded into thinking that the match had to
3423        start at the start point or following a newline. The same bug applied to
3424        patterns with negative forward assertions or any backward assertions
3425        preceding ".*" at the start, unless the pattern required a fixed first
3426        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
3428    10. In UTF-8 mode, when moving forwards in the subject after a failed match
3429        starting at the last subject character, bytes beyond the end of the subject
3430        string were read.
3432    11. Renamed the variable "class" as "classbits" to make life easier for C++
3433        users. (Previously there was a macro definition, but it apparently wasn't
3434        enough.)
3436    12. Added the new field "tables" to the extra data so that tables can be passed
3437        in at exec time, or the internal tables can be re-selected. This allows
3438        a compiled regex to be saved and re-used at a later time by a different
3439        program that might have everything at different addresses.
3441    13. Modified the pcre-config script so that, when run on Solaris, it shows a
3442        -R library as well as a -L library.
3444    14. The debugging options of pcretest (-d on the command line or D on a
3445        pattern) showed incorrect output for anything following an extended class
3446        that contained multibyte characters and which was followed by a quantifier.
3448    15. Added optional support for general category Unicode character properties
3449        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
3450        support. It adds about 90K to the size of the library. The meanings of the
3451        inbuilt class escapes such as \d and \s have NOT been changed.
3453    16. Updated pcredemo.c to include calls to free() to release the memory for the
3454        compiled pattern.
3456    17. The generated file chartables.c was being created in the source directory
3457        instead of in the building directory. This caused the build to fail if the
3458        source directory was different from the building directory, and was
3459        read-only.
3461    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
3462        file. No doubt somebody will tell me if they don't make sense... Also added
3463        Dan Mooney's comments about building on OpenVMS.
3465    19. Added support for partial matching via the PCRE_PARTIAL option for
3466        pcre_exec() and the \P data escape in pcretest.
3468    20. Extended pcretest with 3 new pattern features:
3470        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
3471              write the compiled pattern to the file whose name is "rest-of-line".
3472              This is a straight binary dump of the data, with the saved pointer to
3473              the character tables forced to be NULL. The study data, if any, is
3474              written too. After writing, pcretest reads a new pattern.
3476        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
3477              compiled pattern from the given file. There must not be any
3478              occurrences of "<" in the file name (pretty unlikely); if there are,
3479              pcretest will instead treat the initial "<" as a pattern delimiter.
3480              After reading in the pattern, pcretest goes on to read data lines as
3481              usual.
3483        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
3484              and 16-bit fields in a compiled pattern, to simulate a pattern that
3485              was compiled on a host of opposite endianness.
3487    21. The pcre-exec() function can now cope with patterns that were compiled on
3488        hosts of opposite endianness, with this restriction:
3490          As for any compiled expression that is saved and used later, the tables
3491          pointer field cannot be preserved; the extra_data field in the arguments
3492          to pcre_exec() should be used to pass in a tables address if a value
3493          other than the default internal tables were used at compile time.
3495    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
3496        now diagnosed as an error. Previously, most of the time, a negative number
3497        would have been treated as zero, but if in addition "ovector" was passed as
3498        NULL, a crash could occur.
3500    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
3501        new versions from the libtool 1.5 distribution (the last one is a copy of
3502        a file called libtool.m4). This seems to have fixed the need to patch
3503        "configure" to support Darwin 1.3 (which I used to do). However, I still
3504        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
3505        workstation).
3507    24. Changed the PCRE licence to be the more standard "BSD" licence.
3510    Version 4.5 01-Dec-03
3511    ---------------------
3513     1. There has been some re-arrangement of the code for the match() function so
3514        that it can be compiled in a version that does not call itself recursively.
3515        Instead, it keeps those local variables that need separate instances for
3516        each "recursion" in a frame on the heap, and gets/frees frames whenever it
3517        needs to "recurse". Keeping track of where control must go is done by means
3518        of setjmp/longjmp. The whole thing is implemented by a set of macros that
3519        hide most of the details from the main code, and operates only if
3520        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
3521        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
3522        operating.
3524        To make it easier for callers to provide specially tailored get/free
3525        functions for this usage, two new functions, pcre_stack_malloc, and
3526        pcre_stack_free, are used. They are always called in strict stacking order,
3527        and the size of block requested is always the same.
3529        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
3530        PCRE has been compiled to use the stack or the heap for recursion. The
3531        -C option of pcretest uses this to show which version is compiled.
3533        A new data escape \S, is added to pcretest; it causes the amounts of store
3534        obtained and freed by both kinds of malloc/free at match time to be added
3535        to the output.
3537     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
3538        what's available on my current Linux desktop machine.
3540     3. When matching a UTF-8 string, the test for a valid string at the start has
3541        been extended. If start_offset is not zero, PCRE now checks that it points
3542        to a byte that is the start of a UTF-8 character. If not, it returns
3543        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
3544        this is necessary because there may be backward assertions in the pattern.
3545        When matching the same subject several times, it may save resources to use
3546        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
3548     4. The code for checking the validity of UTF-8 strings has been tightened so
3549        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
3550        containing "overlong sequences".
3552     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
3553        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
3554        should have been "&", but it just so happened that all the cases this let
3555        through by mistake were picked up later in the function.
3557     6. I had used a variable called "isblank" - this is a C99 function, causing
3558        some compilers to warn. To avoid this, I renamed it (as "blankclass").
3560     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
3561        prompting; (b) run "./pcretest /dev/null" at the start of the test script
3562        so the version is shown; (c) stop "make test" echoing "./RunTest".
3564     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
3566     9. The prototype for memmove() for systems that don't have it was using
3567        size_t, but the inclusion of the header that defines size_t was later. I've
3568        moved the #includes for the C headers earlier to avoid this.
3570    10. Added some adjustments to the code to make it easier to compiler on certain
3571        special systems:
3573          (a) Some "const" qualifiers were missing.
3574          (b) Added the macro EXPORT before all exported functions; by default this
3575              is defined to be empty.
3576          (c) Changed the dftables auxiliary program (that builds chartables.c) so
3577              that it reads its output file name as an argument instead of writing
3578              to the standard output and assuming this can be redirected.
3580    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
3581        class containing characters with values greater than 255, PCRE compilation
3582        went into a loop.
3584    12. A recursive reference to a subpattern that was within another subpattern
3585        that had a minimum quantifier of zero caused PCRE to crash. For example,
3586        (x(y(?2))z)? provoked this bug with a subject that got as far as the
3587        recursion. If the recursively-called subpattern itself had a zero repeat,
3588        that was OK.
3590    13. In pcretest, the buffer for reading a data line was set at 30K, but the
3591        buffer into which it was copied (for escape processing) was still set at
3592        1024, so long lines caused crashes.
3594    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
3595        "internal error: code overflow...". This applied to any character class
3596        that was followed by a possessive quantifier.
3598    15. Modified the Makefile to add libpcre.la as a prerequisite for
3599        libpcreposix.la because I was told this is needed for a parallel build to
3600        work.
3602    16. If a pattern that contained .* following optional items at the start was
3603        studied, the wrong optimizing data was generated, leading to matching
3604        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
3605        matching string must start with a or b or c. The correct conclusion for
3606        this pattern is that a match can start with any character.
3609    Version 4.4 13-Aug-03
3610    ---------------------
3612     1. In UTF-8 mode, a character class containing characters with values between
3613        127 and 255 was not handled correctly if the compiled pattern was studied.
3614        In fixing this, I have also improved the studying algorithm for such
3615        classes (slightly).
3617     2. Three internal functions had redundant arguments passed to them. Removal
3618        might give a very teeny performance improvement.
3620     3. Documentation bug: the value of the capture_top field in a callout is *one
3621        more than* the number of the hightest numbered captured substring.
3623     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
3624        in incorrectly linking with a previously installed version. They now link
3625        explicitly with libpcre.la.
3627     5. configure.in no longer needs to recognize Cygwin specially.
3629     6. A problem in pcre.in for Windows platforms is fixed.
3631     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
3632        pcretest, it used to include the size of the study block as part of its
3633        output. Unfortunately, the structure contains a field that has a different
3634        size on different hardware architectures. This meant that the tests that
3635        showed this size failed. As the block is currently always of a fixed size,
3636        this information isn't actually particularly useful in pcretest output, so
3637        I have just removed it.
3639     8. Three pre-processor statements accidentally did not start in column 1.
3640        Sadly, there are *still* compilers around that complain, even though
3641        standard C has not required this for well over a decade. Sigh.
3643     9. In pcretest, the code for checking callouts passed small integers in the
3644        callout_data field, which is a void * field. However, some picky compilers
3645        complained about the casts involved for this on 64-bit systems. Now
3646        pcretest passes the address of the small integer instead, which should get
3647        rid of the warnings.
3649    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
3650        both compile and run time, and gives an error if an invalid UTF-8 sequence
3651        is found. There is a option for disabling this check in cases where the
3652        string is known to be correct and/or the maximum performance is wanted.
3654    11. In response to a bug report, I changed one line in Makefile.in from
3656            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
3657        to
3658            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
3660        to look similar to other lines, but I have no way of telling whether this
3661        is the right thing to do, as I do not use Windows. No doubt I'll get told
3662        if it's wrong...
3665    Version 4.3 21-May-03
3666    ---------------------
3668    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
3669       Makefile.
3671    2. Some refactoring to improve the quality of the code:
3673       (i)   The utf8_table... variables are now declared "const".
3675       (ii)  The code for \cx, which used the "case flipping" table to upper case
3676             lower case letters, now just substracts 32. This is ASCII-specific,
3677             but the whole concept of \cx is ASCII-specific, so it seems
3678             reasonable.
3680       (iii) PCRE was using its character types table to recognize decimal and
3681             hexadecimal digits in the pattern. This is silly, because it handles
3682             only 0-9, a-f, and A-F, but the character types table is locale-
3683             specific, which means strange things might happen. A private
3684             table is now used for this - though it costs 256 bytes, a table is
3685             much faster than multiple explicit tests. Of course, the standard
3686             character types table is still used for matching digits in subject
3687             strings against \d.
3689       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
3690             ending in _t are). So I've renamed it as ESC_tee.
3692    3. The first argument for regexec() in the POSIX wrapper should have been
3693       defined as "const".
3695    4. Changed pcretest to use malloc() for its buffers so that they can be
3696       Electric Fenced for debugging.
3698    5. There were several places in the code where, in UTF-8 mode, PCRE would try
3699       to read one or more bytes before the start of the subject string. Often this
3700       had no effect on PCRE's behaviour, but in some circumstances it could
3701       provoke a segmentation fault.
3703    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
3704       to try to read one or more bytes before the start of the subject string.
3706    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
3707       UTF-8 support could misbehave in various ways if the subject string
3708       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
3709       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
3710       back over UTF-8 characters.)
3713    Version 4.2 14-Apr-03
3714    ---------------------
3716    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
3718    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
3719         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
3720         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
3721         [WIN_PREFIX]: new variable, "cyg" for Cygwin
3722         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
3723           and BUILD_EXEEXT
3724         Note: automatic setting of the BUILD variables is not yet working
3725         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
3726           compile-time but not at link-time
3727         [LINK]: use for linking executables only
3728         make different versions for Windows and non-Windows
3729         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
3730           libraries
3731         [LINK_FOR_BUILD]: new variable
3732         [OBJEXT]: use throughout
3733         [EXEEXT]: use throughout
3734         <winshared>: new target
3735         <wininstall>: new target
3736         <dftables.o>: use native compiler
3737         <dftables>: use native linker
3738         <install>: handle Windows platform correctly
3739         <clean>: ditto
3740         <check>: ditto
3741         copy DLL to top builddir before testing
3743       As part of these changes, -no-undefined was removed again. This was reported
3744       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
3745       in any case.
3747    3. Some tidies to get rid of compiler warnings:
3749       . In the match_data structure, match_limit was an unsigned long int, whereas
3750         match_call_count was an int. I've made them both unsigned long ints.
3752       . In pcretest the fact that a const uschar * doesn't automatically cast to
3753         a void * provoked a warning.
3755       . Turning on some more compiler warnings threw up some "shadow" variables
3756         and a few more missing casts.
3758    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
3759       option, a class that contained a single character with a value between 128
3760       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
3762    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
3763       option, a class that contained several characters, but with at least one
3764       whose value was between 128 and 255 caused PCRE to crash.
3767  Version 4.1 12-Mar-03  Version 4.1 12-Mar-03
3768  ---------------------  ---------------------

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