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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.10 16-Jun-2010  Version 8.31
5    -----------------------------
7    1.  Fixing a wrong JIT test case and some compiler warnings.
9    2.  Removed a bashism from the RunTest script.
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
45    9.  (*MARK) control verb is now supported by the JIT compiler.
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
68    17. The Unicode data tables have been updated to Unicode 6.1.0.
70    18. Added --file-list option to pcregrep.
72    19. Added binary file support to pcregrep, including the -a, --binary-files,
73        -I, and --text options.
75    20. The madvise function is renamed for posix_madvise for QNX compatibility
76        reasons. Fixed by Giuseppe D'Angelo.
78    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
80    22. Changed the option for creating symbolic links for 16-bit man pages from
81        -s to -sf so that re-installing does not cause issues.
83    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
85    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
86        matches in certain environments (the workspace was not being correctly
87        retained). Also added to pcre_dfa_exec() a simple plausibility check on
88        some of the workspace data at the beginning of a restart.
90    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
91        was not doing so when it should - probably a typo introduced by SVN 528
92        (change 8.10/14).
94    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
95        \w+ when the character tables indicated that \x{c4} was a word character.
96        There were several related cases, all because the tests for doing a table
97        lookup were testing for characters less than 127 instead of 255.
99    27. If a pattern contains capturing parentheses that are not used in a match,
100        their slots in the ovector are set to -1. For those that are higher than
101        any matched groups, this happens at the end of processing. In the case when
102        there were back references that the ovector was too small to contain
103        (causing temporary malloc'd memory to be used during matching), and the
104        highest capturing number was not used, memory off the end of the ovector
105        was incorrectly being set to -1. (It was using the size of the temporary
106        memory instead of the true size.)
108    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
109        ovector size, it uses memory at the end of the block that it has got.
112    Version 8.30 04-February-2012
113    -----------------------------
115    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
116        name is defined in ctype.h.
118    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
119        only in quite long subpatterns.
121    3.  Removed the function pcre_info(), which has been obsolete and deprecated
122        since it was replaced by pcre_fullinfo() in February 2000.
124    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
125        match a (*MARK), and the match failed at the start of the subject, a
126        reference to memory before the start of the subject could occur. This bug
127        was introduced by fix 17 of release 8.21.
129    5.  A reference to an unset group with zero minimum repetition was giving
130        totally wrong answers (in non-JavaScript-compatibility mode). For example,
131        /(another)?(\1?)test/ matched against "hello world test". This bug was
132        introduced in release 8.13.
134    6.  Add support for 16-bit character strings (a large amount of work involving
135        many changes and refactorings).
137    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
138        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
139        from a file.
141    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
142        rounding is not applied in this particular case).
144    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
145        if they appear, or are escaped, in patterns.
147    10. Get rid of a number of -Wunused-but-set-variable warnings.
149    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
150        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
151        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
152        also returns the mark "x". This bug applied to capturing parentheses,
153        non-capturing parentheses, and atomic parentheses. It also applied to some
154        assertions.
156    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
157        information out of configure.ac instead of relying on pcre.h.generic, which
158        is not stored in the repository.
160    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
161        -lreadline.
163    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
165    15. Applied Graycode's patch to put the top-level frame on the stack rather
166        than the heap when not using the stack for recursion. This gives a
167        performance improvement in many cases when recursion is not deep.
169    16. Experimental code added to "pcretest -C" to output the stack frame size.
172    Version 8.21 12-Dec-2011
173    ------------------------
175    1.  Updating the JIT compiler.
177    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
178        are added as well.
180    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
181        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
182        calling _pcre_jit_exec. Some extra comments are added.
184    4.  (*MARK) settings inside atomic groups that do not contain any capturing
185        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
186        was introduced by change 18 for 8.20.
188    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
189        ECMA-262 standard.
191    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
192        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
193        This bug was probably introduced by change 9 of 8.13.
195    7.  While fixing 6 above, I noticed that a number of other items were being
196        incorrectly rejected as "not fixed length". This arose partly because newer
197        opcodes had not been added to the fixed-length checking code. I have (a)
198        corrected the bug and added tests for these items, and (b) arranged for an
199        error to occur if an unknown opcode is encountered while checking for fixed
200        length instead of just assuming "not fixed length". The items that were
201        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
202        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
203        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
205    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
206        being incorrectly compiled and would have given unpredicatble results.
208    9.  A possessively repeated subpattern with minimum repeat count greater than
209        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
210        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
211        the first (A) could occur when it should not.
213    10. Add a cast and remove a redundant test from the code.
215    11. JIT should use pcre_malloc/pcre_free for allocation.
217    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
218        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
219        is anything other than /usr, -L is still shown).
221    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
223    14. Perl does not support \N without a following name in a [] class; PCRE now
224        also gives an error.
226    15. If a forward reference was repeated with an upper limit of around 2000,
227        it caused the error "internal error: overran compiling workspace". The
228        maximum number of forward references (including repeats) was limited by the
229        internal workspace, and dependent on the LINK_SIZE. The code has been
230        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
231        the default depends on LINK_SIZE. There is a new upper limit (for safety)
232        of around 200,000 forward references. While doing this, I also speeded up
233        the filling in of repeated forward references.
235    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
236        incorrectly expecting the subject to contain another "a" after the start.
238    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
239        in the match, the SKIP should be ignored. This was not happening; instead
240        the SKIP was being treated as NOMATCH. For patterns such as
241        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
242        tested.
244    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
245        now much more compatible with Perl, in particular in cases where the result
246        is a non-match for a non-anchored pattern. For example, if
247        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
248        "m", where previously it did not return a name. A side effect of this
249        change is that for partial matches, the last encountered mark name is
250        returned, as for non matches. A number of tests that were previously not
251        Perl-compatible have been moved into the Perl-compatible test files. The
252        refactoring has had the pleasing side effect of removing one argument from
253        the match() function, thus reducing its stack requirements.
255    19. If the /S+ option was used in pcretest to study a pattern using JIT,
256        subsequent uses of /S (without +) incorrectly behaved like /S+.
258    21. Retrieve executable code size support for the JIT compiler and fixing
259        some warnings.
261    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
262        not work when the shorter character appeared right at the end of the
263        subject string.
265    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
266        systems.
268    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
269        output it when the /M option is used in pcretest.
271    25. The CheckMan script was not being included in the distribution. Also, added
272        an explicit "perl" to run Perl scripts from the PrepareRelease script
273        because this is reportedly needed in Windows.
275    26. If study data was being save in a file and studying had not found a set of
276        "starts with" bytes for the pattern, the data written to the file (though
277        never used) was taken from uninitialized memory and so caused valgrind to
278        complain.
280    27. Updated RunTest.bat as provided by Sheri Pierce.
282    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
284    29. Computation of memory usage for the table of capturing group names was
285        giving an unnecessarily large value.
288    Version 8.20 21-Oct-2011
289    ------------------------
291    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
292        a POSIX class. After further experiments with Perl, which convinced me that
293        Perl has bugs and confusions, a closing square bracket is no longer allowed
294        in a POSIX name. This bug also affected patterns with classes that started
295        with full stops.
297    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
298        captured substring, but while checking the failing first alternative,
299        substring 1 is temporarily captured. If the output vector supplied to
300        pcre_exec() was not big enough for this capture, the yield of the function
301        was still zero ("insufficient space for captured substrings"). This cannot
302        be totally fixed without adding another stack variable, which seems a lot
303        of expense for a edge case. However, I have improved the situation in cases
304        such as /(a)(b)x|abc/ matched against "abc", where the return code
305        indicates that fewer than the maximum number of slots in the ovector have
306        been set.
308    3.  Related to (2) above: when there are more back references in a pattern than
309        slots in the output vector, pcre_exec() uses temporary memory during
310        matching, and copies in the captures as far as possible afterwards. It was
311        using the entire output vector, but this conflicts with the specification
312        that only 2/3 is used for passing back captured substrings. Now it uses
313        only the first 2/3, for compatibility. This is, of course, another edge
314        case.
316    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
317        main code base, and can be used by building with --enable-jit. When this is
318        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
319        runtime --no-jit option is given.
321    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
322        ovector, the return from the function was zero, implying that there were
323        other matches that did not fit. The correct "exactly full" value is now
324        returned.
326    6.  If a subpattern that was called recursively or as a subroutine contained
327        (*PRUNE) or any other control that caused it to give a non-standard return,
328        invalid errors such as "Error -26 (nested recursion at the same subject
329        position)" or even infinite loops could occur.
331    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
332        computing the minimum length on reaching *ACCEPT, and so ended up with the
333        wrong value of 1 rather than 0. Further investigation indicates that
334        computing a minimum subject length in the presence of *ACCEPT is difficult
335        (think back references, subroutine calls), and so I have changed the code
336        so that no minimum is registered for a pattern that contains *ACCEPT.
338    8.  If (*THEN) was present in the first (true) branch of a conditional group,
339        it was not handled as intended. [But see 16 below.]
341    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
342        Sheri Pierce.
344    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
345        the first byte in a match must be "a".
347    11. Change 17 for 8.13 increased the recursion depth for patterns like
348        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
349        pattern contains any instances of (*THEN). If it does not, the old
350        optimizations are restored. It would be nice to do this on a per-group
351        basis, but at the moment that is not feasible.
353    12. In some environments, the output of pcretest -C is CRLF terminated. This
354        broke RunTest's code that checks for the link size. A single white space
355        character after the value is now allowed for.
357    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
358        For "fr", it uses the Windows-specific input and output files.
360    14. If (*THEN) appeared in a group that was called recursively or as a
361        subroutine, it did not work as intended. [But see next item.]
363    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
364        pattern fragments (but not containing any | characters). If A and B are
365        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
366        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
367        D. In other words, Perl considers parentheses that do not contain any |
368        characters to be part of a surrounding alternative, whereas PCRE was
369        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
370        differently. PCRE now behaves in the same way as Perl, except in the case
371        of subroutine/recursion calls such as (?1) which have in any case always
372        been different (but PCRE had them first :-).
374    16. Related to 15 above: Perl does not treat the | in a conditional group as
375        creating alternatives. Such a group is treated in the same way as an
376        ordinary group without any | characters when processing (*THEN). PCRE has
377        been changed to match Perl's behaviour.
379    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
380        RunGrepTest script failed.
382    18. Change 22 for version 13 caused atomic groups to use more stack. This is
383        inevitable for groups that contain captures, but it can lead to a lot of
384        stack use in large patterns. The old behaviour has been restored for atomic
385        groups that do not contain any capturing parentheses.
387    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
388        suppress the check for a minimum subject length at run time. (If it was
389        given to pcre_exec() or pcre_dfa_exec() it did work.)
391    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
392        fail to work when decoding hex characters in data strings in EBCDIC
393        environments.
395    21. It appears that in at least one Mac OS environment, the isxdigit() function
396        is implemented as a macro that evaluates to its argument more than once,
397        contravening the C 90 Standard (I haven't checked a later standard). There
398        was an instance in pcretest which caused it to go wrong when processing
399        \x{...} escapes in subject strings. The has been rewritten to avoid using
400        things like p++ in the argument of isxdigit().
403    Version 8.13 16-Aug-2011
404    ------------------------
406    1.  The Unicode data tables have been updated to Unicode 6.0.0.
408    2.  Two minor typos in pcre_internal.h have been fixed.
410    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
411        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
412        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
414    4.  There were a number of related bugs in the code for matching backrefences
415        caselessly in UTF-8 mode when codes for the characters concerned were
416        different numbers of bytes. For example, U+023A and U+2C65 are an upper
417        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
418        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
419        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
420        2-byte code at the end of the subject (it thought there wasn't enough data
421        left).
423    5.  Comprehensive information about what went wrong is now returned by
424        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
425        as the output vector has at least 2 elements. The offset of the start of
426        the failing character and a reason code are placed in the vector.
428    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
429        now returned is for the first byte of the failing character, instead of the
430        last byte inspected. This is an incompatible change, but I hope it is small
431        enough not to be a problem. It makes the returned offset consistent with
432        pcre_exec() and pcre_dfa_exec().
434    7.  pcretest now gives a text phrase as well as the error number when
435        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
436        failure, the offset and reason code are output.
438    8.  When \R was used with a maximizing quantifier it failed to skip backwards
439        over a \r\n pair if the subsequent match failed. Instead, it just skipped
440        back over a single character (\n). This seems wrong (because it treated the
441        two characters as a single entity when going forwards), conflicts with the
442        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
443        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
444        has been changed.
446    9.  Some internal refactoring has changed the processing so that the handling
447        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
448        time (the PCRE_DOTALL option was changed this way some time ago: version
449        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
450        which was always a bit of a fudge. It also means that there is one less
451        argument for the match() function, which reduces its stack requirements
452        slightly. This change also fixes an incompatibility with Perl: the pattern
453        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
455    10. More internal refactoring has drastically reduced the number of recursive
456        calls to match() for possessively repeated groups such as (abc)++ when
457        using pcre_exec().
459    11. While implementing 10, a number of bugs in the handling of groups were
460        discovered and fixed:
462        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
463        (a|)*(?1) gave a compile-time internal error.
464        ((a|)+)+  did not notice that the outer group could match an empty string.
465        (^a|^)+   was not marked as anchored.
466        (.*a|.*)+ was not marked as matching at start or after a newline.
468    12. Yet more internal refactoring has removed another argument from the match()
469        function. Special calls to this function are now indicated by setting a
470        value in a variable in the "match data" data block.
472    13. Be more explicit in pcre_study() instead of relying on "default" for
473        opcodes that mean there is no starting character; this means that when new
474        ones are added and accidentally left out of pcre_study(), testing should
475        pick them up.
477    14. The -s option of pcretest has been documented for ages as being an old
478        synonym of -m (show memory usage). I have changed it to mean "force study
479        for every regex", that is, assume /S for every regex. This is similar to -i
480        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
481        using it. It makes it easier to run collections of tests with and without
482        study enabled, and thereby test pcre_study() more easily. All the standard
483        tests are now run with and without -s (but some patterns can be marked as
484        "never study" - see 20 below).
486    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
487        restoration of the capturing data to the outer values was not happening
488        correctly.
490    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
491        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
492        pattern had matched an empty string, and so incorrectly returned a no
493        match.
495    17. There was optimizing code for the last branch of non-capturing parentheses,
496        and also for the obeyed branch of a conditional subexpression, which used
497        tail recursion to cut down on stack usage. Unfortunately, now that there is
498        the possibility of (*THEN) occurring in these branches, tail recursion is
499        no longer possible because the return has to be checked for (*THEN). These
500        two optimizations have therefore been removed. [But see 8.20/11 above.]
502    18. If a pattern containing \R was studied, it was assumed that \R always
503        matched two bytes, thus causing the minimum subject length to be
504        incorrectly computed because \R can also match just one byte.
506    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
507        was incorrectly computed.
509    20. If /S is present twice on a test pattern in pcretest input, it now
510        *disables* studying, thereby overriding the use of -s on the command line
511        (see 14 above). This is necessary for one or two tests to keep the output
512        identical in both cases.
514    21. When (*ACCEPT) was used in an assertion that matched an empty string and
515        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
517    22. When an atomic group that contained a capturing parenthesis was
518        successfully matched, but the branch in which it appeared failed, the
519        capturing was not being forgotten if a higher numbered group was later
520        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
521        group 1 to "a", when in fact it should be unset. This applied to multi-
522        branched capturing and non-capturing groups, repeated or not, and also to
523        positive assertions (capturing in negative assertions does not happen
524        in PCRE) and also to nested atomic groups.
526    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
527        subject after a captured substring, to make it easier to tell which of a
528        number of identical substrings has been captured.
530    24. The way atomic groups are processed by pcre_exec() has been changed so that
531        if they are repeated, backtracking one repetition now resets captured
532        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
533        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
534        "aaa". Previously, it would have been "a". As part of this code
535        refactoring, the way recursive calls are handled has also been changed.
537    25. If an assertion condition captured any substrings, they were not passed
538        back unless some other capturing happened later. For example, if
539        (?(?=(a))a) was matched against "a", no capturing was returned.
541    26. When studying a pattern that contained subroutine calls or assertions,
542        the code for finding the minimum length of a possible match was handling
543        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
544        group 1 called group 2 while simultaneously a separate group 2 called group
545        1). A stack overflow occurred in this case. I have fixed this by limiting
546        the recursion depth to 10.
548    27. Updated RunTest.bat in the distribution to the version supplied by Tom
549        Fortmann. This supports explicit test numbers on the command line, and has
550        argument validation and error reporting.
552    28. An instance of \X with an unlimited repeat could fail if at any point the
553        first character it looked at was a mark character.
555    29. Some minor code refactoring concerning Unicode properties and scripts
556        should reduce the stack requirement of match() slightly.
558    30. Added the '=' option to pcretest to check the setting of unused capturing
559        slots at the end of the pattern, which are documented as being -1, but are
560        not included in the return count.
562    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
563        compiled something random. Now it gives a compile-time error (as does
564        Perl).
566    32. A *MARK encountered during the processing of a positive assertion is now
567        recorded and passed back (compatible with Perl).
569    33. If --only-matching or --colour was set on a pcregrep call whose pattern
570        had alternative anchored branches, the search for a second match in a line
571        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
572        matched the line "0102" twice. The same bug affected patterns that started
573        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
574        twice.
576    34. Previously, PCRE did not allow quantification of assertions. However, Perl
577        does, and because of capturing effects, quantifying parenthesized
578        assertions may at times be useful. Quantifiers are now allowed for
579        parenthesized assertions.
581    35. A minor code tidy in pcre_compile() when checking options for \R usage.
583    36. \g was being checked for fancy things in a character class, when it should
584        just be a literal "g".
586    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
587        appearance of a nested POSIX class supersedes an apparent external class.
588        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
589        unescaped square brackets may also appear as part of class names. For
590        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
591        more like Perl. (But see 8.20/1 above.)
593    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
594        was because it thought it was \N{name}, which is not supported).
596    39. Add minix to OS list not supporting the -S option in pcretest.
598    40. PCRE tries to detect cases of infinite recursion at compile time, but it
599        cannot analyze patterns in sufficient detail to catch mutual recursions
600        such as ((?1))((?2)). There is now a runtime test that gives an error if a
601        subgroup is called recursively as a subpattern for a second time at the
602        same position in the subject string. In previous releases this might have
603        been caught by the recursion limit, or it might have run out of stack.
605    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
606        happen only once. PCRE was, however incorrectly giving a compile time error
607        "recursive call could loop indefinitely" because it cannot analyze the
608        pattern in sufficient detail. The compile time test no longer happens when
609        PCRE is compiling a conditional subpattern, but actual runaway loops are
610        now caught at runtime (see 40 above).
612    42. It seems that Perl allows any characters other than a closing parenthesis
613        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
614        has been changed to be the same.
616    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
617        as not to get warnings when autogen.sh is called. Also changed
618        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
620    44. To help people who use pcregrep to scan files containing exceedingly long
621        lines, the following changes have been made:
623        (a) The default value of the buffer size parameter has been increased from
624            8K to 20K. (The actual buffer used is three times this size.)
626        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
627            PCRE is built.
629        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
630            to be set at run time.
632        (d) Numerical values in pcregrep options can be followed by K or M, for
633            example --buffer-size=50K.
635        (e) If a line being scanned overflows pcregrep's buffer, an error is now
636            given and the return code is set to 2.
638    45. Add a pointer to the latest mark to the callout data block.
640    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
641        partial match of an empty string instead of no match. This was specific to
642        the use of ".".
644    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
645        complete match instead of a partial match. This bug was dependent on both
646        the PCRE_UTF8 and PCRE_DOTALL options being set.
648    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
649        starting byte set, because \b was not being ignored.
652    Version 8.12 15-Jan-2011
653    ------------------------
655    1.  Fixed some typos in the markup of the man pages, and wrote a script that
656        checks for such things as part of the documentation building process.
658    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
659        --match-limit and --recursion-limit options (added for 8.11). In
660        particular, this made one of the standard tests fail. (The integer value
661        went into the wrong half of a long int.)
663    3.  If the --colour option was given to pcregrep with -v (invert match), it
664        did strange things, either producing crazy output, or crashing. It should,
665        of course, ignore a request for colour when reporting lines that do not
666        match.
668    4.  Another pcregrep bug caused similar problems if --colour was specified with
669        -M (multiline) and the pattern match finished with a line ending.
671    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
672        matched in multiline mode, the following line was shown as part of the
673        match. This seems wrong, so I have changed it.
675    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
676        the check for further matches in the same line (so they could be coloured)
677        to overrun the end of the current line. If another match was found, it was
678        incorrectly shown (and then shown again when found in the next line).
680    7.  If pcregrep was compiled under Windows, there was a reference to the
681        function pcregrep_exit() before it was defined. I am assuming this was
682        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
683        reported by a user. I've moved the definition above the reference.
686    Version 8.11 10-Dec-2010
687    ------------------------
689    1.  (*THEN) was not working properly if there were untried alternatives prior
690        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
691        backtracked to try for "b" instead of moving to the next alternative branch
692        at the same level (in this case, to look for "c"). The Perl documentation
693        is clear that when (*THEN) is backtracked onto, it goes to the "next
694        alternative in the innermost enclosing group".
696    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
697        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
698        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
699        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
700        (*THEN).
702    3.  If \s appeared in a character class, it removed the VT character from
703        the class, even if it had been included by some previous item, for example
704        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
705        of \s, but is part of the POSIX "space" class.)
707    4.  A partial match never returns an empty string (because you can always
708        match an empty string at the end of the subject); however the checking for
709        an empty string was starting at the "start of match" point. This has been
710        changed to the "earliest inspected character" point, because the returned
711        data for a partial match starts at this character. This means that, for
712        example, /(?<=abc)def/ gives a partial match for the subject "abc"
713        (previously it gave "no match").
715    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
716        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
717        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
718        has an implication that the given string is incomplete (because a partial
719        match is preferred over a full match). For this reason, these items now
720        give a partial match in this situation. [Aside: previously, the one case
721        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
722        match rather than a full match, which was wrong by the old rules, but is
723        now correct.]
725    6.  There was a bug in the handling of #-introduced comments, recognized when
726        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
727        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
728        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
729        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
730        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
731        places in pcre_compile().
733    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
734        comments when looking ahead for named forward references to subpatterns,
735        the only newline sequence it recognized was NL. It now handles newlines
736        according to the set newline convention.
738    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
739        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
740        cater for a lack of strerror(). These oversights have been fixed.
742    9.  Added --match-limit and --recursion-limit to pcregrep.
744    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
746    11. When the -o option was used, pcregrep was setting a return code of 1, even
747        when matches were found, and --line-buffered was not being honoured.
749    12. Added an optional parentheses number to the -o and --only-matching options
750        of pcregrep.
752    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
753        can match an empty string. The code to do it in pcretest and pcredemo
754        needed fixing:
756        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
757            only one byte after an empty string match just before CRLF (this case
758            just got forgotten; "any" and "anycrlf" were OK).
760        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
761            mode when an empty string match preceded an ASCII character followed by
762            a non-ASCII character. (The code for advancing by one character rather
763            than one byte was nonsense.)
765        (c) The pcredemo.c sample program did not have any code at all to handle
766            the cases when CRLF is a valid newline sequence.
768    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
769        as a starting offset was within the subject string. There is now a new
770        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
771        negative or greater than the length of the string. In order to test this,
772        pcretest is extended to allow the setting of negative starting offsets.
774    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
775        starting offset points to the beginning of a UTF-8 character was
776        unnecessarily clumsy. I tidied it up.
778    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
779        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
781    17. Nobody had reported that the --include_dir option, which was added in
782        release 7.7 should have been called --include-dir (hyphen, not underscore)
783        for compatibility with GNU grep. I have changed it to --include-dir, but
784        left --include_dir as an undocumented synonym, and the same for
785        --exclude-dir, though that is not available in GNU grep, at least as of
786        release 2.5.4.
788    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
789        characters from a string of bytes) have been redefined so as not to use
790        loops, in order to improve performance in some environments. At the same
791        time, I abstracted some of the common code into auxiliary macros to save
792        repetition (this should not affect the compiled code).
794    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
795        compile-time error is now given if \c is not followed by an ASCII
796        character, that is, a byte less than 128. (In EBCDIC mode, the code is
797        different, and any byte value is allowed.)
799    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
800        START_OPTIMIZE option, which is now allowed at compile time - but just
801        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
802        to pcregrep and other applications that have no direct access to PCRE
803        options. The new /Y option in pcretest sets this option when calling
804        pcre_compile().
806    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
807        back references. Groups containing recursive back references were forced to
808        be atomic by that change, but in the case of named groups, the amount of
809        memory required was incorrectly computed, leading to "Failed: internal
810        error: code overflow". This has been fixed.
812    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
813        pcretest.c, to avoid build problems in some Borland environments.
816    Version 8.10 25-Jun-2010
817  ------------------------  ------------------------
819  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and

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