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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.3 05-Jul-07  Version 8.33 xx-xxxx-201x
5    -------------------------
7    1.  Added 'U' to some constants that are compared to unsigned integers, to
8        avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
9        variables that are added to signed variables, to ensure the result is
10        signed and can be negated.
12    2.  Applied patch by Daniel Richard G for quashing MSVC warnings to the
13        CMake config files.
15    3.  Revise the creation of config.h.generic so that all boolean macros are
16        #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
17        overriding via -D on the command line possible.
19    4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
20        to unsigned int is reported to make a quite noticeable speed difference in
21        a specific Windows environment. Testing on Linux did also appear to show
22        some benefit (and it is clearly not harmful). Also fixed the definition of
23        Xop which should be unsigned.
25    5.  Related to (4), changing the definition of the intermediate variable cc
26        in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
27        improvements.
29    6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
30        unnecessary spaces.
32    7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
33        and later.
35    8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
37    9.  Optimizing fast_forward_start_bits in JIT.
39    10. Adding experimental support for callouts in JIT, and fixing some
40        issues revealed during this work. Namely:
42        (a) Unoptimized capturing brackets incorrectly reset on backtrack.
44        (b) Minimum length was not checked before the matching is started.
46    11. The value of capture_last that is passed to callouts was incorrect in some
47        cases when there was a capture on one path that was subsequently abandoned
48        after a backtrack. Also, the capture_last value is now reset after a
49        recursion, since all captures are also reset in this case.
51    12. The interpreter no longer returns the "too many substrings" error in the
52        case when an overflowing capture is in a branch that is subsequently
53        abandoned after a backtrack.
55    13. In the pathological case when an offset vector of size 2 is used, pcretest
56        now prints out the matched string after a yield of 0 or 1.
58    14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
59        Only supported by the JIT compiler at the moment.
61    15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
63    16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
64        offset of the starting point of the matching process, provided the offsets
65        vector is large enough.
67    17. The \A escape now records a lookbehind value of 1, though its execution
68        does not actually inspect the previous character. This is to ensure that,
69        in partial multi-segment matching, at least one character from the old
70        segment is retained when a new segment is processed. Otherwise, if there
71        are no lookbehinds in the pattern, \A might match incorrectly at the start
72        of a new segment.
74    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
76    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
77        gives some modest performance improvement in 8-bit mode.
79    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
80        be expressed in certain programming languages using Universal Character
81        Names.
83    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
84        which points out that "non characters" are not "characters that may not
85        appear in Unicode strings" but rather "characters that are reserved for
86        internal use and have only local meaning".
88    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
89        there was a conditional group that depended on an assertion, if the
90        assertion was false, the callout that immediately followed the alternation
91        in the condition was skipped when pcre_exec() was used for matching.
94    Version 8.32 30-November-2012
95    -----------------------------
97    1.  Improved JIT compiler optimizations for first character search and single
98        character iterators.
100    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
101        Patch by Daniel Richard G.
103    3.  Single character iterator optimizations in the JIT compiler.
105    4.  Improved JIT compiler optimizations for character ranges.
107    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
108        Reported by Giuseppe D'Angelo.
110    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
111        of a line, was being set incorrectly in cases where .* appeared inside
112        atomic brackets at the start of a pattern, or where there was a subsequent
113        *PRUNE or *SKIP.
115    7.  Improved instruction cache flush for POWER/PowerPC.
116        Patch by Daniel Richard G.
118    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
119        grep:
121        (a) There is now no limit to the number of patterns to be matched.
123        (b) An error is given if a pattern is too long.
125        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
126            are now supported.
128        (d) --exclude-from and --include-from (multiple use) have been added.
130        (e) Exclusions and inclusions now apply to all files and directories, not
131            just to those obtained from scanning a directory recursively.
133        (f) Multiple uses of -f and --file-list are now supported.
135        (g) In a Windows environment, the default for -d has been changed from
136            "read" (the GNU grep default) to "skip", because otherwise the presence
137            of a directory in the file list provokes an error.
139        (h) The documentation has been revised and clarified in places.
141    9.  Improve the matching speed of capturing brackets.
143    10. Changed the meaning of \X so that it now matches a Unicode extended
144        grapheme cluster.
146    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
147        out POSIX threads when JIT support is configured.
149    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
151    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
152        structure could go wrong in environments where size_t is not the same size
153        as int.
155    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
156        set.
158    15. The EBCDIC support had decayed; later updates to the code had included
159        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
160        general tidy up of EBCDIC-related issues, and the documentation was also
161        not quite right. There is now a test that can be run on ASCII systems to
162        check some of the EBCDIC-related things (but is it not a full test).
164    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
165        in a small tidy to the code.
167    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
169    18. If the --only-matching (-o) option in pcregrep is specified multiple
170        times, each one causes appropriate output. For example, -o1 -o2 outputs the
171        substrings matched by the 1st and 2nd capturing parentheses. A separating
172        string can be specified by --om-separator (default empty).
174    19. Improving the first n character searches.
176    20. Turn case lists for horizontal and vertical white space into macros so that
177        they are defined only once.
179    21. This set of changes together give more compatible Unicode case-folding
180        behaviour for characters that have more than one other case when UCP
181        support is available.
183        (a) The Unicode property table now has offsets into a new table of sets of
184            three or more characters that are case-equivalent. The MultiStage2.py
185            script that generates these tables (the pcre_ucd.c file) now scans
186            CaseFolding.txt instead of UnicodeData.txt for character case
187            information.
189        (b) The code for adding characters or ranges of characters to a character
190            class has been abstracted into a generalized function that also handles
191            case-independence. In UTF-mode with UCP support, this uses the new data
192            to handle characters with more than one other case.
194        (c) A bug that is fixed as a result of (b) is that codepoints less than 256
195            whose other case is greater than 256 are now correctly matched
196            caselessly. Previously, the high codepoint matched the low one, but not
197            vice versa.
199        (d) The processing of \h, \H, \v, and \ in character classes now makes use
200            of the new class addition function, using character lists defined as
201            macros alongside the case definitions of 20 above.
203        (e) Caseless back references now work with characters that have more than
204            one other case.
206        (f) General caseless matching of characters with more than one other case
207            is supported.
209    22. Unicode character properties were updated from Unicode 6.2.0
211    23. Improved CMake support under Windows. Patch by Daniel Richard G.
213    24. Add support for 32-bit character strings, and UTF-32
215    25. Major JIT compiler update (code refactoring and bugfixing).
216        Experimental Sparc 32 support is added.
218    26. Applied a modified version of Daniel Richard G's patch to create
219        pcre.h.generic and config.h.generic by "make" instead of in the
220        PrepareRelease script.
222    27. Added a definition for CHAR_NULL (helpful for the z/OS port), and use it in
223        pcre_compile.c when checking for a zero character.
225    28. Introducing a native interface for JIT. Through this interface, the compiled
226        machine code can be directly executed. The purpose of this interface is to
227        provide fast pattern matching, so several sanity checks are not performed.
228        However, feature tests are still performed. The new interface provides
229        1.4x speedup compared to the old one.
231    29. If pcre_exec() or pcre_dfa_exec() was called with a negative value for
232        the subject string length, the error given was PCRE_ERROR_BADOFFSET, which
233        was confusing. There is now a new error PCRE_ERROR_BADLENGTH for this case.
235    30. In 8-bit UTF-8 mode, pcretest failed to give an error for data codepoints
236        greater than 0x7fffffff (which cannot be represented in UTF-8, even under
237        the "old" RFC 2279). Instead, it ended up passing a negative length to
238        pcre_exec().
240    31. Add support for GCC's visibility feature to hide internal functions.
242    32. Running "pcretest -C pcre8" or "pcretest -C pcre16" gave a spurious error
243        "unknown -C option" after outputting 0 or 1.
245    33. There is now support for generating a code coverage report for the test
246        suite in environments where gcc is the compiler and lcov is installed. This
247        is mainly for the benefit of the developers.
249    34. If PCRE is built with --enable-valgrind, certain memory regions are marked
250        unaddressable using valgrind annotations, allowing valgrind to detect
251        invalid memory accesses. This is mainly for the benefit of the developers.
253    25. (*UTF) can now be used to start a pattern in any of the three libraries.
255    26. Give configure error if --enable-cpp but no C++ compiler found.
258    Version 8.31 06-July-2012
259    -------------------------
261    1.  Fixing a wrong JIT test case and some compiler warnings.
263    2.  Removed a bashism from the RunTest script.
265    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
266        to unsigned type, result still unsigned" that was given by an MS compiler
267        on encountering the code "-sizeof(xxx)".
269    4.  Partial matching support is added to the JIT compiler.
271    5.  Fixed several bugs concerned with partial matching of items that consist
272        of more than one character:
274        (a) /^(..)\1/ did not partially match "aba" because checking references was
275            done on an "all or nothing" basis. This also applied to repeated
276            references.
278        (b) \R did not give a hard partial match if \r was found at the end of the
279            subject.
281        (c) \X did not give a hard partial match after matching one or more
282            characters at the end of the subject.
284        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
285            a partial match for the string "\r".
287        (e) When newline was set to CRLF, the metacharacter "." did not recognize
288            a partial match for a CR character at the end of the subject string.
290    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
291        running pcretest, the text "(JIT)" added to the output whenever JIT is
292        actually used to run the match.
294    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
295        or /S+[+] with a digit between 1 and 7.
297    8.  OP_NOT now supports any UTF character not just single-byte ones.
299    9.  (*MARK) control verb is now supported by the JIT compiler.
301    10. The command "./RunTest list" lists the available tests without actually
302        running any of them. (Because I keep forgetting what they all are.)
306    12. Applied a (slightly modified) user-supplied patch that improves performance
307        when the heap is used for recursion (compiled with --disable-stack-for-
308        recursion). Instead of malloc and free for each heap frame each time a
309        logical recursion happens, frames are retained on a chain and re-used where
310        possible. This sometimes gives as much as 30% improvement.
312    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
313        call.
315    14. As documented, (*COMMIT) is now confined to within a positive assertion.
317    15. It is now possible to link pcretest with libedit as an alternative to
318        libreadline.
320    16. (*COMMIT) control verb is now supported by the JIT compiler.
322    17. The Unicode data tables have been updated to Unicode 6.1.0.
324    18. Added --file-list option to pcregrep.
326    19. Added binary file support to pcregrep, including the -a, --binary-files,
327        -I, and --text options.
329    20. The madvise function is renamed for posix_madvise for QNX compatibility
330        reasons. Fixed by Giuseppe D'Angelo.
332    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
334    22. Changed the option for creating symbolic links for 16-bit man pages from
335        -s to -sf so that re-installing does not cause issues.
337    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
339    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
340        matches in certain environments (the workspace was not being correctly
341        retained). Also added to pcre_dfa_exec() a simple plausibility check on
342        some of the workspace data at the beginning of a restart.
344    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
345        was not doing so when it should - probably a typo introduced by SVN 528
346        (change 8.10/14).
348    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
349        \w+ when the character tables indicated that \x{c4} was a word character.
350        There were several related cases, all because the tests for doing a table
351        lookup were testing for characters less than 127 instead of 255.
353    27. If a pattern contains capturing parentheses that are not used in a match,
354        their slots in the ovector are set to -1. For those that are higher than
355        any matched groups, this happens at the end of processing. In the case when
356        there were back references that the ovector was too small to contain
357        (causing temporary malloc'd memory to be used during matching), and the
358        highest capturing number was not used, memory off the end of the ovector
359        was incorrectly being set to -1. (It was using the size of the temporary
360        memory instead of the true size.)
362    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
363        ovector size, it uses memory at the end of the block that it has got.
365    29. Check for an overlong MARK name and give an error at compile time. The
366        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
368    30. JIT compiler update.
370    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
371        Rill for the patch.
373    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
375    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
377    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
378        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
379        was enabled.
381    35. Improve JIT code generation for greedy plus quantifier.
383    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
384        1 to "aa" instead of to an empty string. The bug affected repeated groups
385        that could potentially match an empty string.
387    37. Optimizing single character iterators in JIT.
389    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
390        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
391        codepoints that are too big for the mode are faulted, and in a UTF mode,
392        disallowed codepoints are also faulted.
394    39. If PCRE was compiled with UTF support, in three places in the DFA
395        matcher there was code that should only have been obeyed in UTF mode, but
396        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
397        processing when bytes with values greater than 127 were present. In 16-bit
398        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
399        both cases the values are those that cannot be the first data item in a UTF
400        character. The three items that might have provoked this were recursions,
401        possessively repeated groups, and atomic groups.
403    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
404        and pcregrep, because some OS require shared objects to be explicitly
405        passed to ld, causing the link step to fail if they are not.
407    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
408        mode, patterns that started with \h* or \R* might be incorrectly matched.
411    Version 8.30 04-February-2012
412    -----------------------------
414    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
415        name is defined in ctype.h.
417    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
418        only in quite long subpatterns.
420    3.  Removed the function pcre_info(), which has been obsolete and deprecated
421        since it was replaced by pcre_fullinfo() in February 2000.
423    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
424        match a (*MARK), and the match failed at the start of the subject, a
425        reference to memory before the start of the subject could occur. This bug
426        was introduced by fix 17 of release 8.21.
428    5.  A reference to an unset group with zero minimum repetition was giving
429        totally wrong answers (in non-JavaScript-compatibility mode). For example,
430        /(another)?(\1?)test/ matched against "hello world test". This bug was
431        introduced in release 8.13.
433    6.  Add support for 16-bit character strings (a large amount of work involving
434        many changes and refactorings).
436    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
437        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
438        from a file.
440    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
441        rounding is not applied in this particular case).
443    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
444        if they appear, or are escaped, in patterns.
446    10. Get rid of a number of -Wunused-but-set-variable warnings.
448    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
449        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
450        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
451        also returns the mark "x". This bug applied to capturing parentheses,
452        non-capturing parentheses, and atomic parentheses. It also applied to some
453        assertions.
455    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
456        information out of configure.ac instead of relying on pcre.h.generic, which
457        is not stored in the repository.
459    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
460        -lreadline.
462    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
464    15. Applied Graycode's patch to put the top-level frame on the stack rather
465        than the heap when not using the stack for recursion. This gives a
466        performance improvement in many cases when recursion is not deep.
468    16. Experimental code added to "pcretest -C" to output the stack frame size.
471    Version 8.21 12-Dec-2011
472    ------------------------
474    1.  Updating the JIT compiler.
476    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
477        are added as well.
479    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
480        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
481        calling _pcre_jit_exec. Some extra comments are added.
483    4.  (*MARK) settings inside atomic groups that do not contain any capturing
484        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
485        was introduced by change 18 for 8.20.
487    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
488        ECMA-262 standard.
490    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
491        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
492        This bug was probably introduced by change 9 of 8.13.
494    7.  While fixing 6 above, I noticed that a number of other items were being
495        incorrectly rejected as "not fixed length". This arose partly because newer
496        opcodes had not been added to the fixed-length checking code. I have (a)
497        corrected the bug and added tests for these items, and (b) arranged for an
498        error to occur if an unknown opcode is encountered while checking for fixed
499        length instead of just assuming "not fixed length". The items that were
500        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
501        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
502        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
504    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
505        being incorrectly compiled and would have given unpredicatble results.
507    9.  A possessively repeated subpattern with minimum repeat count greater than
508        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
509        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
510        the first (A) could occur when it should not.
512    10. Add a cast and remove a redundant test from the code.
514    11. JIT should use pcre_malloc/pcre_free for allocation.
516    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
517        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
518        is anything other than /usr, -L is still shown).
520    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
522    14. Perl does not support \N without a following name in a [] class; PCRE now
523        also gives an error.
525    15. If a forward reference was repeated with an upper limit of around 2000,
526        it caused the error "internal error: overran compiling workspace". The
527        maximum number of forward references (including repeats) was limited by the
528        internal workspace, and dependent on the LINK_SIZE. The code has been
529        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
530        the default depends on LINK_SIZE. There is a new upper limit (for safety)
531        of around 200,000 forward references. While doing this, I also speeded up
532        the filling in of repeated forward references.
534    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
535        incorrectly expecting the subject to contain another "a" after the start.
537    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
538        in the match, the SKIP should be ignored. This was not happening; instead
539        the SKIP was being treated as NOMATCH. For patterns such as
540        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
541        tested.
543    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
544        now much more compatible with Perl, in particular in cases where the result
545        is a non-match for a non-anchored pattern. For example, if
546        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
547        "m", where previously it did not return a name. A side effect of this
548        change is that for partial matches, the last encountered mark name is
549        returned, as for non matches. A number of tests that were previously not
550        Perl-compatible have been moved into the Perl-compatible test files. The
551        refactoring has had the pleasing side effect of removing one argument from
552        the match() function, thus reducing its stack requirements.
554    19. If the /S+ option was used in pcretest to study a pattern using JIT,
555        subsequent uses of /S (without +) incorrectly behaved like /S+.
557    21. Retrieve executable code size support for the JIT compiler and fixing
558        some warnings.
560    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
561        not work when the shorter character appeared right at the end of the
562        subject string.
564    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
565        systems.
567    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
568        output it when the /M option is used in pcretest.
570    25. The CheckMan script was not being included in the distribution. Also, added
571        an explicit "perl" to run Perl scripts from the PrepareRelease script
572        because this is reportedly needed in Windows.
574    26. If study data was being save in a file and studying had not found a set of
575        "starts with" bytes for the pattern, the data written to the file (though
576        never used) was taken from uninitialized memory and so caused valgrind to
577        complain.
579    27. Updated RunTest.bat as provided by Sheri Pierce.
581    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
583    29. Computation of memory usage for the table of capturing group names was
584        giving an unnecessarily large value.
587    Version 8.20 21-Oct-2011
588    ------------------------
590    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
591        a POSIX class. After further experiments with Perl, which convinced me that
592        Perl has bugs and confusions, a closing square bracket is no longer allowed
593        in a POSIX name. This bug also affected patterns with classes that started
594        with full stops.
596    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
597        captured substring, but while checking the failing first alternative,
598        substring 1 is temporarily captured. If the output vector supplied to
599        pcre_exec() was not big enough for this capture, the yield of the function
600        was still zero ("insufficient space for captured substrings"). This cannot
601        be totally fixed without adding another stack variable, which seems a lot
602        of expense for a edge case. However, I have improved the situation in cases
603        such as /(a)(b)x|abc/ matched against "abc", where the return code
604        indicates that fewer than the maximum number of slots in the ovector have
605        been set.
607    3.  Related to (2) above: when there are more back references in a pattern than
608        slots in the output vector, pcre_exec() uses temporary memory during
609        matching, and copies in the captures as far as possible afterwards. It was
610        using the entire output vector, but this conflicts with the specification
611        that only 2/3 is used for passing back captured substrings. Now it uses
612        only the first 2/3, for compatibility. This is, of course, another edge
613        case.
615    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
616        main code base, and can be used by building with --enable-jit. When this is
617        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
618        runtime --no-jit option is given.
620    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
621        ovector, the return from the function was zero, implying that there were
622        other matches that did not fit. The correct "exactly full" value is now
623        returned.
625    6.  If a subpattern that was called recursively or as a subroutine contained
626        (*PRUNE) or any other control that caused it to give a non-standard return,
627        invalid errors such as "Error -26 (nested recursion at the same subject
628        position)" or even infinite loops could occur.
630    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
631        computing the minimum length on reaching *ACCEPT, and so ended up with the
632        wrong value of 1 rather than 0. Further investigation indicates that
633        computing a minimum subject length in the presence of *ACCEPT is difficult
634        (think back references, subroutine calls), and so I have changed the code
635        so that no minimum is registered for a pattern that contains *ACCEPT.
637    8.  If (*THEN) was present in the first (true) branch of a conditional group,
638        it was not handled as intended. [But see 16 below.]
640    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
641        Sheri Pierce.
643    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
644        the first byte in a match must be "a".
646    11. Change 17 for 8.13 increased the recursion depth for patterns like
647        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
648        pattern contains any instances of (*THEN). If it does not, the old
649        optimizations are restored. It would be nice to do this on a per-group
650        basis, but at the moment that is not feasible.
652    12. In some environments, the output of pcretest -C is CRLF terminated. This
653        broke RunTest's code that checks for the link size. A single white space
654        character after the value is now allowed for.
656    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
657        For "fr", it uses the Windows-specific input and output files.
659    14. If (*THEN) appeared in a group that was called recursively or as a
660        subroutine, it did not work as intended. [But see next item.]
662    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
663        pattern fragments (but not containing any | characters). If A and B are
664        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
665        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
666        D. In other words, Perl considers parentheses that do not contain any |
667        characters to be part of a surrounding alternative, whereas PCRE was
668        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
669        differently. PCRE now behaves in the same way as Perl, except in the case
670        of subroutine/recursion calls such as (?1) which have in any case always
671        been different (but PCRE had them first :-).
673    16. Related to 15 above: Perl does not treat the | in a conditional group as
674        creating alternatives. Such a group is treated in the same way as an
675        ordinary group without any | characters when processing (*THEN). PCRE has
676        been changed to match Perl's behaviour.
678    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
679        RunGrepTest script failed.
681    18. Change 22 for version 13 caused atomic groups to use more stack. This is
682        inevitable for groups that contain captures, but it can lead to a lot of
683        stack use in large patterns. The old behaviour has been restored for atomic
684        groups that do not contain any capturing parentheses.
686    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
687        suppress the check for a minimum subject length at run time. (If it was
688        given to pcre_exec() or pcre_dfa_exec() it did work.)
690    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
691        fail to work when decoding hex characters in data strings in EBCDIC
692        environments.
694    21. It appears that in at least one Mac OS environment, the isxdigit() function
695        is implemented as a macro that evaluates to its argument more than once,
696        contravening the C 90 Standard (I haven't checked a later standard). There
697        was an instance in pcretest which caused it to go wrong when processing
698        \x{...} escapes in subject strings. The has been rewritten to avoid using
699        things like p++ in the argument of isxdigit().
702    Version 8.13 16-Aug-2011
703    ------------------------
705    1.  The Unicode data tables have been updated to Unicode 6.0.0.
707    2.  Two minor typos in pcre_internal.h have been fixed.
709    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
710        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
711        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
713    4.  There were a number of related bugs in the code for matching backrefences
714        caselessly in UTF-8 mode when codes for the characters concerned were
715        different numbers of bytes. For example, U+023A and U+2C65 are an upper
716        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
717        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
718        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
719        2-byte code at the end of the subject (it thought there wasn't enough data
720        left).
722    5.  Comprehensive information about what went wrong is now returned by
723        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
724        as the output vector has at least 2 elements. The offset of the start of
725        the failing character and a reason code are placed in the vector.
727    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
728        now returned is for the first byte of the failing character, instead of the
729        last byte inspected. This is an incompatible change, but I hope it is small
730        enough not to be a problem. It makes the returned offset consistent with
731        pcre_exec() and pcre_dfa_exec().
733    7.  pcretest now gives a text phrase as well as the error number when
734        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
735        failure, the offset and reason code are output.
737    8.  When \R was used with a maximizing quantifier it failed to skip backwards
738        over a \r\n pair if the subsequent match failed. Instead, it just skipped
739        back over a single character (\n). This seems wrong (because it treated the
740        two characters as a single entity when going forwards), conflicts with the
741        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
742        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
743        has been changed.
745    9.  Some internal refactoring has changed the processing so that the handling
746        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
747        time (the PCRE_DOTALL option was changed this way some time ago: version
748        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
749        which was always a bit of a fudge. It also means that there is one less
750        argument for the match() function, which reduces its stack requirements
751        slightly. This change also fixes an incompatibility with Perl: the pattern
752        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
754    10. More internal refactoring has drastically reduced the number of recursive
755        calls to match() for possessively repeated groups such as (abc)++ when
756        using pcre_exec().
758    11. While implementing 10, a number of bugs in the handling of groups were
759        discovered and fixed:
761        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
762        (a|)*(?1) gave a compile-time internal error.
763        ((a|)+)+  did not notice that the outer group could match an empty string.
764        (^a|^)+   was not marked as anchored.
765        (.*a|.*)+ was not marked as matching at start or after a newline.
767    12. Yet more internal refactoring has removed another argument from the match()
768        function. Special calls to this function are now indicated by setting a
769        value in a variable in the "match data" data block.
771    13. Be more explicit in pcre_study() instead of relying on "default" for
772        opcodes that mean there is no starting character; this means that when new
773        ones are added and accidentally left out of pcre_study(), testing should
774        pick them up.
776    14. The -s option of pcretest has been documented for ages as being an old
777        synonym of -m (show memory usage). I have changed it to mean "force study
778        for every regex", that is, assume /S for every regex. This is similar to -i
779        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
780        using it. It makes it easier to run collections of tests with and without
781        study enabled, and thereby test pcre_study() more easily. All the standard
782        tests are now run with and without -s (but some patterns can be marked as
783        "never study" - see 20 below).
785    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
786        restoration of the capturing data to the outer values was not happening
787        correctly.
789    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
790        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
791        pattern had matched an empty string, and so incorrectly returned a no
792        match.
794    17. There was optimizing code for the last branch of non-capturing parentheses,
795        and also for the obeyed branch of a conditional subexpression, which used
796        tail recursion to cut down on stack usage. Unfortunately, now that there is
797        the possibility of (*THEN) occurring in these branches, tail recursion is
798        no longer possible because the return has to be checked for (*THEN). These
799        two optimizations have therefore been removed. [But see 8.20/11 above.]
801    18. If a pattern containing \R was studied, it was assumed that \R always
802        matched two bytes, thus causing the minimum subject length to be
803        incorrectly computed because \R can also match just one byte.
805    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
806        was incorrectly computed.
808    20. If /S is present twice on a test pattern in pcretest input, it now
809        *disables* studying, thereby overriding the use of -s on the command line
810        (see 14 above). This is necessary for one or two tests to keep the output
811        identical in both cases.
813    21. When (*ACCEPT) was used in an assertion that matched an empty string and
814        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
816    22. When an atomic group that contained a capturing parenthesis was
817        successfully matched, but the branch in which it appeared failed, the
818        capturing was not being forgotten if a higher numbered group was later
819        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
820        group 1 to "a", when in fact it should be unset. This applied to multi-
821        branched capturing and non-capturing groups, repeated or not, and also to
822        positive assertions (capturing in negative assertions does not happen
823        in PCRE) and also to nested atomic groups.
825    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
826        subject after a captured substring, to make it easier to tell which of a
827        number of identical substrings has been captured.
829    24. The way atomic groups are processed by pcre_exec() has been changed so that
830        if they are repeated, backtracking one repetition now resets captured
831        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
832        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
833        "aaa". Previously, it would have been "a". As part of this code
834        refactoring, the way recursive calls are handled has also been changed.
836    25. If an assertion condition captured any substrings, they were not passed
837        back unless some other capturing happened later. For example, if
838        (?(?=(a))a) was matched against "a", no capturing was returned.
840    26. When studying a pattern that contained subroutine calls or assertions,
841        the code for finding the minimum length of a possible match was handling
842        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
843        group 1 called group 2 while simultaneously a separate group 2 called group
844        1). A stack overflow occurred in this case. I have fixed this by limiting
845        the recursion depth to 10.
847    27. Updated RunTest.bat in the distribution to the version supplied by Tom
848        Fortmann. This supports explicit test numbers on the command line, and has
849        argument validation and error reporting.
851    28. An instance of \X with an unlimited repeat could fail if at any point the
852        first character it looked at was a mark character.
854    29. Some minor code refactoring concerning Unicode properties and scripts
855        should reduce the stack requirement of match() slightly.
857    30. Added the '=' option to pcretest to check the setting of unused capturing
858        slots at the end of the pattern, which are documented as being -1, but are
859        not included in the return count.
861    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
862        compiled something random. Now it gives a compile-time error (as does
863        Perl).
865    32. A *MARK encountered during the processing of a positive assertion is now
866        recorded and passed back (compatible with Perl).
868    33. If --only-matching or --colour was set on a pcregrep call whose pattern
869        had alternative anchored branches, the search for a second match in a line
870        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
871        matched the line "0102" twice. The same bug affected patterns that started
872        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
873        twice.
875    34. Previously, PCRE did not allow quantification of assertions. However, Perl
876        does, and because of capturing effects, quantifying parenthesized
877        assertions may at times be useful. Quantifiers are now allowed for
878        parenthesized assertions.
880    35. A minor code tidy in pcre_compile() when checking options for \R usage.
882    36. \g was being checked for fancy things in a character class, when it should
883        just be a literal "g".
885    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
886        appearance of a nested POSIX class supersedes an apparent external class.
887        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
888        unescaped square brackets may also appear as part of class names. For
889        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
890        more like Perl. (But see 8.20/1 above.)
892    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
893        was because it thought it was \N{name}, which is not supported).
895    39. Add minix to OS list not supporting the -S option in pcretest.
897    40. PCRE tries to detect cases of infinite recursion at compile time, but it
898        cannot analyze patterns in sufficient detail to catch mutual recursions
899        such as ((?1))((?2)). There is now a runtime test that gives an error if a
900        subgroup is called recursively as a subpattern for a second time at the
901        same position in the subject string. In previous releases this might have
902        been caught by the recursion limit, or it might have run out of stack.
904    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
905        happen only once. PCRE was, however incorrectly giving a compile time error
906        "recursive call could loop indefinitely" because it cannot analyze the
907        pattern in sufficient detail. The compile time test no longer happens when
908        PCRE is compiling a conditional subpattern, but actual runaway loops are
909        now caught at runtime (see 40 above).
911    42. It seems that Perl allows any characters other than a closing parenthesis
912        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
913        has been changed to be the same.
915    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
916        as not to get warnings when autogen.sh is called. Also changed
917        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
919    44. To help people who use pcregrep to scan files containing exceedingly long
920        lines, the following changes have been made:
922        (a) The default value of the buffer size parameter has been increased from
923            8K to 20K. (The actual buffer used is three times this size.)
925        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
926            PCRE is built.
928        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
929            to be set at run time.
931        (d) Numerical values in pcregrep options can be followed by K or M, for
932            example --buffer-size=50K.
934        (e) If a line being scanned overflows pcregrep's buffer, an error is now
935            given and the return code is set to 2.
937    45. Add a pointer to the latest mark to the callout data block.
939    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
940        partial match of an empty string instead of no match. This was specific to
941        the use of ".".
943    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
944        complete match instead of a partial match. This bug was dependent on both
945        the PCRE_UTF8 and PCRE_DOTALL options being set.
947    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
948        starting byte set, because \b was not being ignored.
951    Version 8.12 15-Jan-2011
952    ------------------------
954    1.  Fixed some typos in the markup of the man pages, and wrote a script that
955        checks for such things as part of the documentation building process.
957    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
958        --match-limit and --recursion-limit options (added for 8.11). In
959        particular, this made one of the standard tests fail. (The integer value
960        went into the wrong half of a long int.)
962    3.  If the --colour option was given to pcregrep with -v (invert match), it
963        did strange things, either producing crazy output, or crashing. It should,
964        of course, ignore a request for colour when reporting lines that do not
965        match.
967    4.  Another pcregrep bug caused similar problems if --colour was specified with
968        -M (multiline) and the pattern match finished with a line ending.
970    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
971        matched in multiline mode, the following line was shown as part of the
972        match. This seems wrong, so I have changed it.
974    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
975        the check for further matches in the same line (so they could be coloured)
976        to overrun the end of the current line. If another match was found, it was
977        incorrectly shown (and then shown again when found in the next line).
979    7.  If pcregrep was compiled under Windows, there was a reference to the
980        function pcregrep_exit() before it was defined. I am assuming this was
981        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
982        reported by a user. I've moved the definition above the reference.
985    Version 8.11 10-Dec-2010
986    ------------------------
988    1.  (*THEN) was not working properly if there were untried alternatives prior
989        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
990        backtracked to try for "b" instead of moving to the next alternative branch
991        at the same level (in this case, to look for "c"). The Perl documentation
992        is clear that when (*THEN) is backtracked onto, it goes to the "next
993        alternative in the innermost enclosing group".
995    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
996        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
997        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
998        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
999        (*THEN).
1001    3.  If \s appeared in a character class, it removed the VT character from
1002        the class, even if it had been included by some previous item, for example
1003        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
1004        of \s, but is part of the POSIX "space" class.)
1006    4.  A partial match never returns an empty string (because you can always
1007        match an empty string at the end of the subject); however the checking for
1008        an empty string was starting at the "start of match" point. This has been
1009        changed to the "earliest inspected character" point, because the returned
1010        data for a partial match starts at this character. This means that, for
1011        example, /(?<=abc)def/ gives a partial match for the subject "abc"
1012        (previously it gave "no match").
1014    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
1015        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
1016        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
1017        has an implication that the given string is incomplete (because a partial
1018        match is preferred over a full match). For this reason, these items now
1019        give a partial match in this situation. [Aside: previously, the one case
1020        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
1021        match rather than a full match, which was wrong by the old rules, but is
1022        now correct.]
1024    6.  There was a bug in the handling of #-introduced comments, recognized when
1025        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
1026        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
1027        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
1028        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
1029        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
1030        places in pcre_compile().
1032    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
1033        comments when looking ahead for named forward references to subpatterns,
1034        the only newline sequence it recognized was NL. It now handles newlines
1035        according to the set newline convention.
1037    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
1038        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
1039        cater for a lack of strerror(). These oversights have been fixed.
1041    9.  Added --match-limit and --recursion-limit to pcregrep.
1043    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
1045    11. When the -o option was used, pcregrep was setting a return code of 1, even
1046        when matches were found, and --line-buffered was not being honoured.
1048    12. Added an optional parentheses number to the -o and --only-matching options
1049        of pcregrep.
1051    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
1052        can match an empty string. The code to do it in pcretest and pcredemo
1053        needed fixing:
1055        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
1056            only one byte after an empty string match just before CRLF (this case
1057            just got forgotten; "any" and "anycrlf" were OK).
1059        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
1060            mode when an empty string match preceded an ASCII character followed by
1061            a non-ASCII character. (The code for advancing by one character rather
1062            than one byte was nonsense.)
1064        (c) The pcredemo.c sample program did not have any code at all to handle
1065            the cases when CRLF is a valid newline sequence.
1067    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
1068        as a starting offset was within the subject string. There is now a new
1069        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
1070        negative or greater than the length of the string. In order to test this,
1071        pcretest is extended to allow the setting of negative starting offsets.
1073    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
1074        starting offset points to the beginning of a UTF-8 character was
1075        unnecessarily clumsy. I tidied it up.
1077    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
1078        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
1080    17. Nobody had reported that the --include_dir option, which was added in
1081        release 7.7 should have been called --include-dir (hyphen, not underscore)
1082        for compatibility with GNU grep. I have changed it to --include-dir, but
1083        left --include_dir as an undocumented synonym, and the same for
1084        --exclude-dir, though that is not available in GNU grep, at least as of
1085        release 2.5.4.
1087    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
1088        characters from a string of bytes) have been redefined so as not to use
1089        loops, in order to improve performance in some environments. At the same
1090        time, I abstracted some of the common code into auxiliary macros to save
1091        repetition (this should not affect the compiled code).
1093    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
1094        compile-time error is now given if \c is not followed by an ASCII
1095        character, that is, a byte less than 128. (In EBCDIC mode, the code is
1096        different, and any byte value is allowed.)
1098    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
1099        START_OPTIMIZE option, which is now allowed at compile time - but just
1100        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
1101        to pcregrep and other applications that have no direct access to PCRE
1102        options. The new /Y option in pcretest sets this option when calling
1103        pcre_compile().
1105    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
1106        back references. Groups containing recursive back references were forced to
1107        be atomic by that change, but in the case of named groups, the amount of
1108        memory required was incorrectly computed, leading to "Failed: internal
1109        error: code overflow". This has been fixed.
1111    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
1112        pcretest.c, to avoid build problems in some Borland environments.
1115    Version 8.10 25-Jun-2010
1116    ------------------------
1118    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
1119        THEN.
1121    2.  (*ACCEPT) was not working when inside an atomic group.
1123    3.  Inside a character class, \B is treated as a literal by default, but
1124        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
1125        causes the error). The code is unchanged, but I tidied the documentation.
1127    4.  Inside a character class, PCRE always treated \R and \X as literals,
1128        whereas Perl faults them if its -w option is set. I have changed PCRE so
1129        that it faults them when PCRE_EXTRA is set.
1131    5.  Added support for \N, which always matches any character other than
1132        newline. (It is the same as "." when PCRE_DOTALL is not set.)
1134    6.  When compiling pcregrep with newer versions of gcc which may have
1135        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
1136        declared with attribute warn_unused_result" were given. Just casting the
1137        result to (void) does not stop the warnings; a more elaborate fudge is
1138        needed. I've used a macro to implement this.
1140    7.  Minor change to pcretest.c to avoid a compiler warning.
1142    8.  Added four artifical Unicode properties to help with an option to make
1143        \s etc use properties (see next item). The new properties are: Xan
1144        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
1146    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
1147        use Unicode properties. (*UCP) at the start of a pattern can be used to set
1148        this option. Modified pcretest to add /W to test this facility. Added
1149        REG_UCP to make it available via the POSIX interface.
1151    10. Added --line-buffered to pcregrep.
1153    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
1154        studied, and the match started with a letter with a code point greater than
1155        127 whose first byte was different to the first byte of the other case of
1156        the letter, the other case of this starting letter was not recognized
1157        (#976).
1159    12. If a pattern that was studied started with a repeated Unicode property
1160        test, for example, \p{Nd}+, there was the theoretical possibility of
1161        setting up an incorrect bitmap of starting bytes, but fortunately it could
1162        not have actually happened in practice until change 8 above was made (it
1163        added property types that matched character-matching opcodes).
1165    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
1166        possible starting bytes for non-anchored patterns.
1168    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
1169        \R, and also a number of cases that involve Unicode properties, both
1170        explicit and implicit when PCRE_UCP is set.
1172    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
1173        input, it could crash or give wrong results if characters with values
1174        greater than 0xc0 were present in the subject string. (Detail: it assumed
1175        UTF-8 input when processing these items.)
1177    16. Added a lot of (int) casts to avoid compiler warnings in systems where
1178        size_t is 64-bit (#991).
1180    17. Added a check for running out of memory when PCRE is compiled with
1181        --disable-stack-for-recursion (#990).
1183    18. If the last data line in a file for pcretest does not have a newline on
1184        the end, a newline was missing in the output.
1186    19. The default pcre_chartables.c file recognizes only ASCII characters (values
1187        less than 128) in its various bitmaps. However, there is a facility for
1188        generating tables according to the current locale when PCRE is compiled. It
1189        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
1190        characters, are recognized by isspace() and therefore were getting set in
1191        these tables, and indeed these tables seem to approximate to ISO 8859. This
1192        caused a problem in UTF-8 mode when pcre_study() was used to create a list
1193        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
1194        which of course cannot start UTF-8 characters. I have changed the code so
1195        that only real ASCII characters (less than 128) and the correct starting
1196        bytes for UTF-8 encodings are set for characters greater than 127 when in
1197        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
1198        altogether.)
1200    20. Added the /T option to pcretest so as to be able to run tests with non-
1201        standard character tables, thus making it possible to include the tests
1202        used for 19 above in the standard set of tests.
1204    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
1205        reference to a subpattern the other side of a comment that contains an
1206        opening parenthesis caused either an internal compiling error, or a
1207        reference to the wrong subpattern.
1210    Version 8.02 19-Mar-2010
1211    ------------------------
1213    1.  The Unicode data tables have been updated to Unicode 5.2.0.
1215    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
1216        configured.
1218    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
1219        original author of that file, following a query about its status.
1221    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
1222        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
1224    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
1225        quantifier applied to a forward-referencing subroutine call, could compile
1226        incorrect code or give the error "internal error: previously-checked
1227        referenced subpattern not found".
1229    6.  Both MS Visual Studio and Symbian OS have problems with initializing
1230        variables to point to external functions. For these systems, therefore,
1231        pcre_malloc etc. are now initialized to local functions that call the
1232        relevant global functions.
1234    7.  There were two entries missing in the vectors called coptable and poptable
1235        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
1236        I've fixed the data, and added a kludgy way of testing at compile time that
1237        the lengths are correct (equal to the number of opcodes).
1239    8.  Following on from 7, I added a similar kludge to check the length of the
1240        eint vector in pcreposix.c.
1242    9.  Error texts for pcre_compile() are held as one long string to avoid too
1243        much relocation at load time. To find a text, the string is searched,
1244        counting zeros. There was no check for running off the end of the string,
1245        which could happen if a new error number was added without updating the
1246        string.
1248    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
1250    11. \K was not working if it appeared in an atomic group or in a group that
1251        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
1252        \K is "not well defined" if used in an assertion. PCRE now accepts it if
1253        the assertion is positive, but not if it is negative.
1255    12. Change 11 fortuitously reduced the size of the stack frame used in the
1256        "match()" function of pcre_exec.c by one pointer. Forthcoming
1257        implementation of support for (*MARK) will need an extra pointer on the
1258        stack; I have reserved it now, so that the stack frame size does not
1259        decrease.
1261    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
1262        item in branch that calls a recursion is a subroutine call - as in the
1263        second branch in the above example - was incorrectly given the compile-
1264        time error "recursive call could loop indefinitely" because pcre_compile()
1265        was not correctly checking the subroutine for matching a non-empty string.
1267    14. The checks for overrunning compiling workspace could trigger after an
1268        overrun had occurred. This is a "should never occur" error, but it can be
1269        triggered by pathological patterns such as hundreds of nested parentheses.
1270        The checks now trigger 100 bytes before the end of the workspace.
1272    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
1275    Version 8.01 19-Jan-2010
1276    ------------------------
1278    1.  If a pattern contained a conditional subpattern with only one branch (in
1279        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
1280        computed the wrong minimum data length (which is of course zero for such
1281        subpatterns). This could cause incorrect "no match" results.
1283    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
1284        the pattern is reset in the first branch, pcre_compile() failed with
1285        "internal error: code overflow at offset...". This happened only when
1286        the reset was to the original external option setting. (An optimization
1287        abstracts leading options settings into an external setting, which was the
1288        cause of this.)
1290    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
1291        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
1292        assertion pattern did not match (meaning that the assertion was true), it
1293        was incorrectly treated as false if the SKIP had been reached during the
1294        matching. This also applied to assertions used as conditions.
1296    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
1297        assertion subpattern, including such a pattern used as a condition,
1298        unpredictable results occurred, instead of the error return
1301    5.  The C++ GlobalReplace function was not working like Perl for the special
1302        situation when an empty string is matched. It now does the fancy magic
1303        stuff that is necessary.
1305    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
1306        removed. (These were left over from very, very early versions of PCRE.)
1308    7.  Some cosmetic changes to the code to make life easier when compiling it
1309        as part of something else:
1311        (a) Change DEBUG to PCRE_DEBUG.
1313        (b) In pcre_compile(), rename the member of the "branch_chain" structure
1314            called "current" as "current_branch", to prevent a collision with the
1315            Linux macro when compiled as a kernel module.
1317        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
1318            prevent a collision with the Linux macro when compiled as a kernel
1319            module.
1321    8.  In pcre_compile() there are some checks for integer overflows that used to
1322        cast potentially large values to (double). This has been changed to that
1323        when building, a check for int64_t is made, and if it is found, it is used
1324        instead, thus avoiding the use of floating point arithmetic. (There is no
1325        other use of FP in PCRE.) If int64_t is not found, the fallback is to
1326        double.
1328    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
1329        2005 (difference between two addresses compared to an unsigned value).
1331    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
1332        custom one, because of the following reported problem in Windows:
1334          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
1335              under Win32.
1336          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
1337              therefore missing the function definition.
1338          - The compiler thus generates a "C" signature for the test function.
1339          - The linker fails to find the "C" function.
1340          - PCRE fails to configure if asked to do so against libbz2.
1342    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1343        messages were output:
1345          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1346          rerunning libtoolize, to keep the correct libtool macros in-tree.
1347          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1349        I have done both of these things.
1351    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1352        most of the time, it *can* run out if it is given a pattern that contains a
1353        runaway infinite recursion. I updated the discussion in the pcrestack man
1354        page.
1356    13. Now that we have gone to the x.xx style of version numbers, the minor
1357        version may start with zero. Using 08 or 09 is a bad idea because users
1358        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1359        interpreted as invalid octal numbers. I've updated the previous comment in
1360        configure.ac, and also added a check that gives an error if 08 or 09 are
1361        used.
1363    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1364        causing partial matching to fail when the end of the subject matched \W
1365        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1367    15. There were some discrepancies between the declarations in pcre_internal.h
1368        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1369        their definitions. The declarations used "const uschar *" and the
1370        definitions used USPTR. Even though USPTR is normally defined as "const
1371        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1372        reported that: "This difference in casting confuses some C++ compilers, for
1373        example, SunCC recognizes above declarations as different functions and
1374        generates broken code for hbpcre." I have changed the declarations to use
1375        USPTR.
1377    16. GNU libtool is named differently on some systems. The autogen.sh script now
1378        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1379        (FreeBSD).
1381    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1382        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1383        comment: "Figure out how to create a longlong from a string: strtoll and
1384        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1385        instance, but it only takes 2 args instead of 3!"
1387    18. A subtle bug concerned with back references has been fixed by a change of
1388        specification, with a corresponding code fix. A pattern such as
1389        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1390        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1391        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1392        same bug. Such groups have to be quantified to be useful, or contained
1393        inside another quantified group. (If there's no repetition, the reference
1394        can never match.) The problem arises because, having left the group and
1395        moved on to the rest of the pattern, a later failure that backtracks into
1396        the group uses the captured value from the final iteration of the group
1397        rather than the correct earlier one. I have fixed this in PCRE by forcing
1398        any group that contains a reference to itself to be an atomic group; that
1399        is, there cannot be any backtracking into it once it has completed. This is
1400        similar to recursive and subroutine calls.
1403    Version 8.00 19-Oct-09
1404    ----------------------
1406    1.  The table for translating pcre_compile() error codes into POSIX error codes
1407        was out-of-date, and there was no check on the pcre_compile() error code
1408        being within the table. This could lead to an OK return being given in
1409        error.
1411    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1412        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1413        in a Windows environment.
1415    3.  The pcregrep --count option prints the count for each file even when it is
1416        zero, as does GNU grep. However, pcregrep was also printing all files when
1417        --files-with-matches was added. Now, when both options are given, it prints
1418        counts only for those files that have at least one match. (GNU grep just
1419        prints the file name in this circumstance, but including the count seems
1420        more useful - otherwise, why use --count?) Also ensured that the
1421        combination -clh just lists non-zero counts, with no names.
1423    4.  The long form of the pcregrep -F option was incorrectly implemented as
1424        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1425        but it seems right to fix it, and I didn't think it was worth preserving
1426        the old behaviour.
1428    5.  The command line items --regex=pattern and --regexp=pattern were not
1429        recognized by pcregrep, which required --regex pattern or --regexp pattern
1430        (with a space rather than an '='). The man page documented the '=' forms,
1431        which are compatible with GNU grep; these now work.
1433    6.  No libpcreposix.pc file was created for pkg-config; there was just
1434        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1436    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1437        when UCP support is not needed, by modifying the Python script that
1438        generates it from Unicode data files. This should not matter if the module
1439        is correctly used as a library, but I received one complaint about 50K of
1440        unwanted data. My guess is that the person linked everything into his
1441        program rather than using a library. Anyway, it does no harm.
1443    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1444        was a minimum greater than 1 for a wide character in a possessive
1445        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1446        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1447        character. Chaos in the form of incorrect output or a compiling loop could
1448        result.
1450    9.  The restrictions on what a pattern can contain when partial matching is
1451        requested for pcre_exec() have been removed. All patterns can now be
1452        partially matched by this function. In addition, if there are at least two
1453        slots in the offset vector, the offset of the earliest inspected character
1454        for the match and the offset of the end of the subject are set in them when
1455        PCRE_ERROR_PARTIAL is returned.
1457    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1458        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1459        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1460        and may be more useful for multi-segment matching.
1462    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1463        used to be given if ever the end of the subject was reached; now it is
1464        given only if matching could not proceed because another character was
1465        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1466        string "Z", which now yields "no match" instead of "partial match". In the
1467        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1468        final character ended with (*FAIL).
1470    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1471        if the pattern had a "must contain" character that was already found in the
1472        earlier partial match, unless partial matching was again requested. For
1473        example, with the pattern /dog.(body)?/, the "must contain" character is
1474        "g". If the first part-match was for the string "dog", restarting with
1475        "sbody" failed. This bug has been fixed.
1477    13. The string returned by pcre_dfa_exec() after a partial match has been
1478        changed so that it starts at the first inspected character rather than the
1479        first character of the match. This makes a difference only if the pattern
1480        starts with a lookbehind assertion or \b or \B (\K is not supported by
1481        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1482        matching functions compatible, and I think it's the right thing to do.
1484    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1485        so that the demonstration program is easily available in environments where
1486        PCRE has not been installed from source.
1488    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1489        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1490        library.
1492    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1493        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1494        is not the first non-POSIX option to be added. Clearly some people find
1495        these options useful.
1497    17. If a caller to the POSIX matching function regexec() passes a non-zero
1498        value for nmatch with a NULL value for pmatch, the value of
1499        nmatch is forced to zero.
1501    18. RunGrepTest did not have a test for the availability of the -u option of
1502        the diff command, as RunTest does. It now checks in the same way as
1503        RunTest, and also checks for the -b option.
1505    19. If an odd number of negated classes containing just a single character
1506        interposed, within parentheses, between a forward reference to a named
1507        subpattern and the definition of the subpattern, compilation crashed with
1508        an internal error, complaining that it could not find the referenced
1509        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1510        [The bug was that it was starting one character too far in when skipping
1511        over the character class, thus treating the ] as data rather than
1512        terminating the class. This meant it could skip too much.]
1514    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1515        /g option in pcretest when the pattern contains \K, which makes it possible
1516        to have an empty string match not at the start, even when the pattern is
1517        anchored. Updated pcretest and pcredemo to use this option.
1519    21. If the maximum number of capturing subpatterns in a recursion was greater
1520        than the maximum at the outer level, the higher number was returned, but
1521        with unset values at the outer level. The correct (outer level) value is
1522        now given.
1524    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1525        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1526        make it do so. The string so far is captured, making this feature
1527        compatible with Perl.
1529    23. The tests have been re-organized, adding tests 11 and 12, to make it
1530        possible to check the Perl 5.10 features against Perl 5.10.
1532    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1533        pattern matches a fixed length string. PCRE did not allow this; now it
1534        does. Neither allows recursion.
1536    25. I finally figured out how to implement a request to provide the minimum
1537        length of subject string that was needed in order to match a given pattern.
1538        (It was back references and recursion that I had previously got hung up
1539        on.) This code has now been added to pcre_study(); it finds a lower bound
1540        to the length of subject needed. It is not necessarily the greatest lower
1541        bound, but using it to avoid searching strings that are too short does give
1542        some useful speed-ups. The value is available to calling programs via
1543        pcre_fullinfo().
1545    26. While implementing 25, I discovered to my embarrassment that pcretest had
1546        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1547        study optimizations had never been tested with that matching function.
1548        Oops. What is worse, even when it was passed study data, there was a bug in
1549        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1550        were also very few tests of studied patterns with pcre_dfa_exec().
1552    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1553        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1554        on the other side of the coin, they are no longer allowed to have different
1555        names, because these cannot be distinguished in PCRE, and this has caused
1556        confusion. (This is a difference from Perl.)
1558    28. When duplicate subpattern names are present (necessarily with different
1559        numbers, as required by 27 above), and a test is made by name in a
1560        conditional pattern, either for a subpattern having been matched, or for
1561        recursion in such a pattern, all the associated numbered subpatterns are
1562        tested, and the overall condition is true if the condition is true for any
1563        one of them. This is the way Perl works, and is also more like the way
1564        testing by number works.
1567    Version 7.9 11-Apr-09
1568    ---------------------
1570    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1571        (pcretest), all targets were linked against these libraries. This included
1572        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1573        libraries. This caused unwanted dependencies to be created. This problem
1574        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1575        pcretest is linked with readline.
1577    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1578        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1579        moved outside it again, because FALSE and TRUE are already defined in AIX,
1580        but BOOL is not.
1582    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1583        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1585    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1586        hyphens) following file names and line numbers when outputting matching
1587        lines. This is not true; no spaces are inserted. I have also clarified the
1588        wording for the --colour (or --color) option.
1590    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1591        was not coloured; this is different to GNU grep, so I have changed it to be
1592        the same.
1594    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1595        each matching line was coloured. Now it goes on to look for further matches
1596        of any of the test patterns, which is the same behaviour as GNU grep.
1598    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1599        doesn't make sense to accept an empty string match in pcregrep, so I have
1600        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1601        seems to be how GNU grep behaves.
1603    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1604        start or after a newline", because the conditional assertion was not being
1605        correctly handled. The rule now is that both the assertion and what follows
1606        in the first alternative must satisfy the test.
1608    9.  If auto-callout was enabled in a pattern with a conditional group whose
1609        condition was an assertion, PCRE could crash during matching, both with
1610        pcre_exec() and pcre_dfa_exec().
1612    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1613        used for matching.
1615    11. Unicode property support in character classes was not working for
1616        characters (bytes) greater than 127 when not in UTF-8 mode.
1618    12. Added the -M command line option to pcretest.
1620    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1622    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1624    16. Added comments and documentation about mis-use of no_arg in the C++
1625        wrapper.
1627    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1628        from Martin Jerabek that uses macro names for all relevant character and
1629        string constants.
1631    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1632        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1633        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1634        these, but not everybody uses configure.
1636    19. A conditional group that had only one branch was not being correctly
1637        recognized as an item that could match an empty string. This meant that an
1638        enclosing group might also not be so recognized, causing infinite looping
1639        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1640        with the subject "ab", where knowledge that the repeated group can match
1641        nothing is needed in order to break the loop.
1643    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1644        exec(), but without supplying a callout function, matching went wrong.
1646    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1647        leak if the size of the offset vector was greater than 30. When the vector
1648        is smaller, the saved offsets during recursion go onto a local stack
1649        vector, but for larger vectors malloc() is used. It was failing to free
1650        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1651        error, in fact).
1653    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1654        heapframe that is used only when UTF-8 support is enabled. This caused no
1655        problem, but was untidy.
1657    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1658        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1659        included within another project.
1661    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1662        slightly modified by me:
1664          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1665              not building pcregrep.
1667          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1668              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1670    25. Forward references, both numeric and by name, in patterns that made use of
1671        duplicate group numbers, could behave incorrectly or give incorrect errors,
1672        because when scanning forward to find the reference group, PCRE was not
1673        taking into account the duplicate group numbers. A pattern such as
1674        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1676    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1677        the feature of a custom pointer more persuasive (as requested by a user).
1679    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1680        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1681        pre-defined.
1683    28. Added support for (*UTF8) at the start of a pattern.
1685    29. Arrange for flags added by the "release type" setting in CMake to be shown
1686        in the configuration summary.
1689    Version 7.8 05-Sep-08
1690    ---------------------
1692    1.  Replaced UCP searching code with optimized version as implemented for Ad
1693        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1694        stage table and inline lookup instead of a function, giving speed ups of 2
1695        to 5 times on some simple patterns that I tested. Permission was given to
1696        distribute the MultiStage2.py script that generates the tables (it's not in
1697        the tarball, but is in the Subversion repository).
1699    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1700        scripts.
1702    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1703        a group with a zero qualifier. The result of the study could be incorrect,
1704        or the function might crash, depending on the pattern.
1706    4.  Caseless matching was not working for non-ASCII characters in back
1707        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1708        It now works when Unicode Property Support is available.
1710    5.  In pcretest, an escape such as \x{de} in the data was always generating
1711        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1712        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1713        truncation.
1715    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1717    7.  Added two (int) casts to pcregrep when printing the difference of two
1718        pointers, in case they are 64-bit values.
1720    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1721        test 2 if it fails.
1723    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1724        and a #define of that name to empty if it is not externally set. This is to
1725        allow users of MSVC to set it if necessary.
1727    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1728        the convenience functions in the pcre_get.c source file.
1730    11. An option change at the start of a pattern that had top-level alternatives
1731        could cause overwriting and/or a crash. This command provoked a crash in
1732        some environments:
1734          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1736        This potential security problem was recorded as CVE-2008-2371.
1738    12. For a pattern where the match had to start at the beginning or immediately
1739        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1740        pcre_dfa_exec() could read past the end of the passed subject if there was
1741        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1742        pcretest so that it places the subject at the end of its malloc-ed buffer.
1744    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1745        exec() might read past the end of the data buffer in UTF-8 mode.
1747    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1748        the data contained the byte 0x85 as part of a UTF-8 character within its
1749        first line. This applied both to normal and DFA matching.
1751    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1752        /^[^d]*?$/8 failed to match "abc".
1754    16. Added a missing copyright notice to pcrecpp_internal.h.
1756    17. Make it more clear in the documentation that values returned from
1757        pcre_exec() in ovector are byte offsets, not character counts.
1759    18. Tidied a few places to stop certain compilers from issuing warnings.
1761    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1762        supplied by Stefan Weber. I made a further small update for 7.8 because
1763        there is a change of source arrangements: the pcre_searchfuncs.c module is
1764        replaced by pcre_ucd.c.
1767    Version 7.7 07-May-08
1768    ---------------------
1770    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1771        a string to a long long, pretend we don't even have a long long." This is
1772        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1774    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1775        pre-7.6 versions, which defined a global no_arg variable instead of putting
1776        it in the RE class. (See also #8 below.)
1778    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1779        Lopes.
1781    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1783        (1) The include/exclude patterns were being applied to the whole pathnames
1784            of files, instead of just to the final components.
1786        (2) If there was more than one level of directory, the subdirectories were
1787            skipped unless they satisfied the include/exclude conditions. This is
1788            inconsistent with GNU grep (and could even be seen as contrary to the
1789            pcregrep specification - which I improved to make it absolutely clear).
1790            The action now is always to scan all levels of directory, and just
1791            apply the include/exclude patterns to regular files.
1793    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1794        --exclude_dir in the tests to avoid scanning .svn directories.
1796    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1797        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1798        doesn't support NULs in patterns.
1800    7.  Added some missing "const"s to declarations of static tables in
1801        pcre_compile.c and pcre_dfa_exec.c.
1803    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1804        caused by fix #2  above. (Subsequently also a second patch to fix the
1805        first patch. And a third patch - this was a messy problem.)
1807    9.  Applied Craig's patch to remove the use of push_back().
1809    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1810        matching function regexec().
1812    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1813        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1814        references. PCRE supports relative numbers with this syntax (I don't think
1815        Oniguruma does).
1817    12. Previously, a group with a zero repeat such as (...){0} was completely
1818        omitted from the compiled regex. However, this means that if the group
1819        was called as a subroutine from elsewhere in the pattern, things went wrong
1820        (an internal error was given). Such groups are now left in the compiled
1821        pattern, with a new opcode that causes them to be skipped at execution
1822        time.
1824    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1825        to the way PCRE behaves:
1827        (a) A lone ] character is dis-allowed (Perl treats it as data).
1829        (b) A back reference to an unmatched subpattern matches an empty string
1830            (Perl fails the current match path).
1832        (c) A data ] in a character class must be notated as \] because if the
1833            first data character in a class is ], it defines an empty class. (In
1834            Perl it is not possible to have an empty class.) The empty class []
1835            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1836            The negative empty class [^] matches any one character, independently
1837            of the DOTALL setting.
1839    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1840        non-existent subpattern following a character class starting with ']' and
1841        containing () gave an internal compiling error instead of "reference to
1842        non-existent subpattern". Fortunately, when the pattern did exist, the
1843        compiled code was correct. (When scanning forwards to check for the
1844        existencd of the subpattern, it was treating the data ']' as terminating
1845        the class, so got the count wrong. When actually compiling, the reference
1846        was subsequently set up correctly.)
1848    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1849        it was being rejected as not supported by pcre_dfa_exec(), even though
1850        other assertions are supported. I have made pcre_dfa_exec() support
1851        (*FAIL).
1853    16. The implementation of 13c above involved the invention of a new opcode,
1854        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1855        cannot be changed at match time, I realized I could make a small
1856        improvement to matching performance by compiling OP_ALLANY instead of
1857        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1858        on the OP_ANY path.
1860    17. Compiling pcretest on Windows with readline support failed without the
1861        following two fixes: (1) Make the unistd.h include conditional on
1862        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1864    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1865        ncurses library to be included for pcretest when ReadLine support is
1866        requested, but also to allow for it to be overridden. This patch came from
1867        Daniel Bergström.
1869    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1870        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1871        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1872        spotting this.
1875    Version 7.6 28-Jan-08
1876    ---------------------
1878    1.  A character class containing a very large number of characters with
1879        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1880        overflow.
1882    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1883        HAVE_LONG_LONG is not defined.
1885    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1886        bring them up to date and include new features. This patch includes:
1888        - Fixed PH's badly added libz and libbz2 support.
1889        - Fixed a problem with static linking.
1890        - Added pcredemo. [But later removed - see 7 below.]
1891        - Fixed dftables problem and added an option.
1892        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1893            HAVE_LONG_LONG.
1894        - Added readline support for pcretest.
1895        - Added an listing of the option settings after cmake has run.
1897    4.  A user submitted a patch to Makefile that makes it easy to create
1898        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1899        Makefile.am that cause it to include this special target, without
1900        affecting anything else. Note that the same mingw target plus all
1901        the other distribution libraries and programs are now supported
1902        when configuring with CMake (see 6 below) instead of with
1903        Configure/Make.
1905    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1906        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1907        exported in the Windows port". It has not yet been confirmed that the patch
1908        solves the problem, but it does no harm.
1910    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1911        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1912        with CMake, and also correct the comment about stack recursion.
1914    7.  Remove the automatic building of pcredemo from the ./configure system and
1915        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1916        of a program that users should build themselves after PCRE is installed, so
1917        building it automatically is not really right. What is more, it gave
1918        trouble in some build environments.
1920    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1923    Version 7.5 10-Jan-08
1924    ---------------------
1926    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1927        values in parens when parsing an RE using the C++ wrapper."
1929    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1930        Characters greater than 255 were excluded from the class instead of being
1931        included.
1933    3.  The same bug as (2) above applied to negated POSIX classes such as
1934        [:^space:].
1936    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1937        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1938        I have changed it.
1940    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1941        first named subpattern) and a construct such as (?&a) would reference the
1942        first named subpattern whose name started with "a" (in other words, the
1943        length check was missing). Both these problems are fixed. "Subpattern name
1944        expected" is now given for (?&) (a zero-length name), and this patch also
1945        makes it give the same error for \k'' (previously it complained that that
1946        was a reference to a non-existent subpattern).
1948    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1949        this is right because (?- can be followed by option settings as well as by
1950        digits. I have, however, made the messages clearer.
1952    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1953        than the number used in the conditional) now cause a compile-time error.
1954        This is actually not compatible with Perl, which accepts such patterns, but
1955        treats the conditional as always being FALSE (as PCRE used to), but it
1956        seems to me that giving a diagnostic is better.
1958    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1959        and messages.
1961    9.  Fix two occurrences of "backslash" in comments that should have been
1962        "backspace".
1964    10. Remove two redundant lines of code that can never be obeyed (their function
1965        was moved elsewhere).
1967    11. The program that makes PCRE's Unicode character property table had a bug
1968        which caused it to generate incorrect table entries for sequences of
1969        characters that have the same character type, but are in different scripts.
1970        It amalgamated them into a single range, with the script of the first of
1971        them. In other words, some characters were in the wrong script. There were
1972        thirteen such cases, affecting characters in the following ranges:
1974          U+002b0 - U+002c1
1975          U+0060c - U+0060d
1976          U+0061e - U+00612
1977          U+0064b - U+0065e
1978          U+0074d - U+0076d
1979          U+01800 - U+01805
1980          U+01d00 - U+01d77
1981          U+01d9b - U+01dbf
1982          U+0200b - U+0200f
1983          U+030fc - U+030fe
1984          U+03260 - U+0327f
1985          U+0fb46 - U+0fbb1
1986          U+10450 - U+1049d
1988    12. The -o option (show only the matching part of a line) for pcregrep was not
1989        compatible with GNU grep in that, if there was more than one match in a
1990        line, it showed only the first of them. It now behaves in the same way as
1991        GNU grep.
1993    13. If the -o and -v options were combined for pcregrep, it printed a blank
1994        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1995        does the same. The return code can be used to tell if there were any
1996        non-matching lines.
1998    14. Added --file-offsets and --line-offsets to pcregrep.
2000    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
2001        infinitely looping recursion. The bug was that positive lookaheads were not
2002        being skipped when checking for a possible empty match (negative lookaheads
2003        and both kinds of lookbehind were skipped).
2005    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
2006        inclusion of <windows.h> to before rather than after the definition of
2007        INVALID_FILE_ATTRIBUTES (patch from David Byron).
2009    17. Specifying a possessive quantifier with a specific limit for a Unicode
2010        character property caused pcre_compile() to compile bad code, which led at
2011        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
2012        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
2013        caused the error; without that there was no problem.
2015    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
2017    19. Added --enable-pcretest-libreadline.
2019    20. In pcrecpp.cc, the variable 'count' was incremented twice in
2020        RE::GlobalReplace(). As a result, the number of replacements returned was
2021        double what it should be. I removed one of the increments, but Craig sent a
2022        later patch that removed the other one (the right fix) and added unit tests
2023        that check the return values (which was not done before).
2025    21. Several CMake things:
2027        (1) Arranged that, when cmake is used on Unix, the libraries end up with
2028            the names libpcre and libpcreposix, not just pcre and pcreposix.
2030        (2) The above change means that pcretest and pcregrep are now correctly
2031            linked with the newly-built libraries, not previously installed ones.
2035    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
2036        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
2037        UTF-8 newline character). The key issue is that the pattern starts .*;
2038        this means that the match must be either at the beginning, or after a
2039        newline. The bug was in the code for advancing after a failed match and
2040        checking that the new position followed a newline. It was not taking
2041        account of UTF-8 characters correctly.
2043    23. PCRE was behaving differently from Perl in the way it recognized POSIX
2044        character classes. PCRE was not treating the sequence [:...:] as a
2045        character class unless the ... were all letters. Perl, however, seems to
2046        allow any characters between [: and :], though of course it rejects as
2047        unknown any "names" that contain non-letters, because all the known class
2048        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
2049        for example, whereas PCRE did not - it did not recognize a POSIX character
2050        class. This seemed a bit dangerous, so the code has been changed to be
2051        closer to Perl. The behaviour is not identical to Perl, because PCRE will
2052        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
2053        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
2054        Perl does, and where it didn't before.
2056    24. Rewrite so as to remove the single use of %n from pcregrep because in some
2057        Windows environments %n is disabled by default.
2060    Version 7.4 21-Sep-07
2061    ---------------------
2063    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
2064        means that a class such as [\s] counted as "explicit reference to CR or
2065        LF". That isn't really right - the whole point of the change was to try to
2066        help when there was an actual mention of one of the two characters. So now
2067        the change happens only if \r or \n (or a literal CR or LF) character is
2068        encountered.
2070    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
2071        of both had grown to the point where there were only 3 bits left.
2072        Fortunately, there was spare space in the data structure, and so I have
2073        moved the internal flags into a new 16-bit field to free up more option
2074        bits.
2076    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
2077        but did not set the internal JCHANGED flag - either of these is enough to
2078        control the way the "get" function works - but the PCRE_INFO_JCHANGED
2079        facility is supposed to tell if (?J) was ever used, so now (?J) at the
2080        start sets both bits.
2082    4.  Added options (at build time, compile time, exec time) to change \R from
2083        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
2085    5.  doc/pcresyntax.html was missing from the distribution.
2087    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
2088        compatibility, even though it is no longer used.
2090    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
2091        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
2092        windows.h file is present (where different names are used). [This was
2093        reversed later after testing - see 16 below.]
2095    8.  Changed all #include <config.h> to #include "config.h". There were also
2096        some further <pcre.h> cases that I changed to "pcre.h".
2098    9.  When pcregrep was used with the --colour option, it missed the line ending
2099        sequence off the lines that it output.
2101    10. It was pointed out to me that arrays of string pointers cause lots of
2102        relocations when a shared library is dynamically loaded. A technique of
2103        using a single long string with a table of offsets can drastically reduce
2104        these. I have refactored PCRE in four places to do this. The result is
2105        dramatic:
2107          Originally:                          290
2108          After changing UCP table:            187
2109          After changing error message table:   43
2110          After changing table of "verbs"       36
2111          After changing table of Posix names   22
2113        Thanks to the folks working on Gregex for glib for this insight.
2115    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
2116        unicode-properties was also set.
2118    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
2120    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
2121        checked only for CRLF.
2123    14. Added casts to pcretest.c to avoid compiler warnings.
2125    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
2127    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
2128        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
2129        entirely. This removes changes made in 7 above.
2131    17. The CMake files have been updated, and there is now more information about
2132        building with CMake in the NON-UNIX-USE document.
2135    Version 7.3 28-Aug-07
2136  ---------------------  ---------------------
2138   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 64  Version 7.3 05-Jul-07 Line 2195  Version 7.3 05-Jul-07
2195      dynamic way, which I have now done. The artificial limitation on group      dynamic way, which I have now done. The artificial limitation on group
2196      length has been removed - we now have only the limit on the total length of      length has been removed - we now have only the limit on the total length of
2197      the compiled pattern, which depends on the LINK_SIZE setting.      the compiled pattern, which depends on the LINK_SIZE setting.
2199  10. Fixed a bug in the documentation for get/copy named substring when  10. Fixed a bug in the documentation for get/copy named substring when
2200      duplicate names are permitted. If none of the named substrings are set, the      duplicate names are permitted. If none of the named substrings are set, the
2201      functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an      functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
2202      empty string.      empty string.
2204  11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E  11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
2205      instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,      instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
2206      because the ] is interpreted as the first data character and the      because the ] is interpreted as the first data character and the
2207      terminating ] is not found. PCRE has been made compatible with Perl in this      terminating ] is not found. PCRE has been made compatible with Perl in this
2208      regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could      regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
2209      cause memory overwriting.      cause memory overwriting.
2211  10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty  10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
2212      string has been matched (to stop an infinite loop). It was not recognizing      string has been matched (to stop an infinite loop). It was not recognizing
2213      a conditional subpattern that could match an empty string if that      a conditional subpattern that could match an empty string if that
2214      subpattern was within another subpattern. For example, it looped when      subpattern was within another subpattern. For example, it looped when
2215      trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the      trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
2216      condition was not nested. This bug has been fixed.      condition was not nested. This bug has been fixed.
2218    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
2219        past the start of the subject in the presence of bytes with the top bit
2220        set, for example "\x8aBCD".
2222    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
2223        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
2225    14. Optimized (?!) to (*FAIL).
2227    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
2228        This restricts code points to be within the range 0 to 0x10FFFF, excluding
2229        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
2230        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
2231        does: it's just the validity check that is more restrictive.
2233    16. Inserted checks for integer overflows during escape sequence (backslash)
2234        processing, and also fixed erroneous offset values for syntax errors during
2235        backslash processing.
2237    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
2238        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
2240    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
2241        caused an overrun.
2243    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
2244        something other than just ASCII characters) inside a group that had an
2245        unlimited repeat caused a loop at compile time (while checking to see
2246        whether the group could match an empty string).
2248    20. Debugging a pattern containing \p or \P could cause a crash. For example,
2249        [\P{Any}] did so. (Error in the code for printing property names.)
2251    21. An orphan \E inside a character class could cause a crash.
2253    22. A repeated capturing bracket such as (A)? could cause a wild memory
2254        reference during compilation.
2256    23. There are several functions in pcre_compile() that scan along a compiled
2257        expression for various reasons (e.g. to see if it's fixed length for look
2258        behind). There were bugs in these functions when a repeated \p or \P was
2259        present in the pattern. These operators have additional parameters compared
2260        with \d, etc, and these were not being taken into account when moving along
2261        the compiled data. Specifically:
2263        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
2264            length.
2266        (b) An item such as \pL+ within a repeated group could cause crashes or
2267            loops.
2269        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
2270            "reference to non-existent subpattern" error.
2272        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
2274    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
2275        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
2277    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
2279    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
2280        character were causing crashes (broken optimization).
2282    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
2283        \p or \P) caused a compile-time loop.
2285    28. More problems have arisen in unanchored patterns when CRLF is a valid line
2286        break. For example, the unstudied pattern [\r\n]A does not match the string
2287        "\r\nA" because change 7.0/46 below moves the current point on by two
2288        characters after failing to match at the start. However, the pattern \nA
2289        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
2290        the same is true. There doesn't seem any very clean way out of this, but
2291        what I have chosen to do makes the common cases work: PCRE now takes note
2292        of whether there can be an explicit match for \r or \n anywhere in the
2293        pattern, and if so, 7.0/46 no longer applies. As part of this change,
2294        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
2295        pattern has explicit CR or LF references.
2297    29. Added (*CR) etc for changing newline setting at start of pattern.
2300  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07
2301  ---------------------  ---------------------

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