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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.32
5    ------------
6    
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
9    
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
12    
13    3.  Single character iterator optimizations in the JIT compiler.
14    
15    4.  Improved JIT compiler optimizations for character ranges.
16    
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
19    
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
24    
25    7.  Improved instruction cache flush for POWER/PowerPC.
26        Patch by Daniel Richard G.
27    
28    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
29        grep:
30    
31        (a) There is now no limit to the number of patterns to be matched.
32    
33        (b) An error is given if a pattern is too long.
34    
35        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
36            are now supported.
37    
38        (d) --exclude-from and --include-from (multiple use) have been added.
39    
40        (e) Exclusions and inclusions now apply to all files and directories, not
41            just to those obtained from scanning a directory recursively.
42    
43        (f) Multiple uses of -f and --file-list are now supported.
44    
45        (g) In a Windows environment, the default for -d has been changed from
46            "read" (the GNU grep default) to "skip", because otherwise the presence
47            of a directory in the file list provokes an error.
48    
49        (h) The documentation has been revised and clarified in places.
50    
51    9.  Improve the matching speed of capturing brackets.
52    
53    10. Changed the meaning of \X so that it now matches a Unicode extended
54        grapheme cluster.
55    
56    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
57        out POSIX threads when JIT support is configured.
58    
59    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
60    
61    13. In the POSIX wrapper regcomp() function, setting re_nsub field in the preg
62        structure could go wrong in environments where size_t is not the same size
63        as int.
64    
65    14. Applied user-supplied patch to pcrecpp.cc to allow PCRE_NO_UTF8_CHECK to be
66        set.
67    
68    15. The EBCDIC support had decayed; later updates to the code had included
69        explicit references to (e.g.) \x0a instead of CHAR_LF. There has been a
70        general tidy up of EBCDIC-related issues, and the documentation was also
71        not quite right. There is now a test that can be run on ASCII systems to
72        check some of the EBCDIC-related things (but is it not a full test).
73    
74    16. The new PCRE_STUDY_EXTRA_NEEDED option is now used by pcregrep, resulting
75        in a small tidy to the code.
76    
77    17. Fix JIT tests when UTF is disabled and both 8 and 16 bit mode are enabled.
78    
79    
80    Version 8.31 06-July-2012
81    -------------------------
82    
83    1.  Fixing a wrong JIT test case and some compiler warnings.
84    
85    2.  Removed a bashism from the RunTest script.
86    
87    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
88        to unsigned type, result still unsigned" that was given by an MS compiler
89        on encountering the code "-sizeof(xxx)".
90    
91    4.  Partial matching support is added to the JIT compiler.
92    
93    5.  Fixed several bugs concerned with partial matching of items that consist
94        of more than one character:
95    
96        (a) /^(..)\1/ did not partially match "aba" because checking references was
97            done on an "all or nothing" basis. This also applied to repeated
98            references.
99    
100        (b) \R did not give a hard partial match if \r was found at the end of the
101            subject.
102    
103        (c) \X did not give a hard partial match after matching one or more
104            characters at the end of the subject.
105    
106        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
107            a partial match for the string "\r".
108    
109        (e) When newline was set to CRLF, the metacharacter "." did not recognize
110            a partial match for a CR character at the end of the subject string.
111    
112    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
113        running pcretest, the text "(JIT)" added to the output whenever JIT is
114        actually used to run the match.
115    
116    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
117        or /S+[+] with a digit between 1 and 7.
118    
119    8.  OP_NOT now supports any UTF character not just single-byte ones.
120    
121    9.  (*MARK) control verb is now supported by the JIT compiler.
122    
123    10. The command "./RunTest list" lists the available tests without actually
124        running any of them. (Because I keep forgetting what they all are.)
125    
126    11. Add PCRE_INFO_MAXLOOKBEHIND.
127    
128    12. Applied a (slightly modified) user-supplied patch that improves performance
129        when the heap is used for recursion (compiled with --disable-stack-for-
130        recursion). Instead of malloc and free for each heap frame each time a
131        logical recursion happens, frames are retained on a chain and re-used where
132        possible. This sometimes gives as much as 30% improvement.
133    
134    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
135        call.
136    
137    14. As documented, (*COMMIT) is now confined to within a positive assertion.
138    
139    15. It is now possible to link pcretest with libedit as an alternative to
140        libreadline.
141    
142    16. (*COMMIT) control verb is now supported by the JIT compiler.
143    
144    17. The Unicode data tables have been updated to Unicode 6.1.0.
145    
146    18. Added --file-list option to pcregrep.
147    
148    19. Added binary file support to pcregrep, including the -a, --binary-files,
149        -I, and --text options.
150    
151    20. The madvise function is renamed for posix_madvise for QNX compatibility
152        reasons. Fixed by Giuseppe D'Angelo.
153    
154    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
155    
156    22. Changed the option for creating symbolic links for 16-bit man pages from
157        -s to -sf so that re-installing does not cause issues.
158    
159    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
160    
161    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
162        matches in certain environments (the workspace was not being correctly
163        retained). Also added to pcre_dfa_exec() a simple plausibility check on
164        some of the workspace data at the beginning of a restart.
165    
166    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
167        was not doing so when it should - probably a typo introduced by SVN 528
168        (change 8.10/14).
169    
170    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
171        \w+ when the character tables indicated that \x{c4} was a word character.
172        There were several related cases, all because the tests for doing a table
173        lookup were testing for characters less than 127 instead of 255.
174    
175    27. If a pattern contains capturing parentheses that are not used in a match,
176        their slots in the ovector are set to -1. For those that are higher than
177        any matched groups, this happens at the end of processing. In the case when
178        there were back references that the ovector was too small to contain
179        (causing temporary malloc'd memory to be used during matching), and the
180        highest capturing number was not used, memory off the end of the ovector
181        was incorrectly being set to -1. (It was using the size of the temporary
182        memory instead of the true size.)
183    
184    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
185        ovector size, it uses memory at the end of the block that it has got.
186    
187    29. Check for an overlong MARK name and give an error at compile time. The
188        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
189    
190    30. JIT compiler update.
191    
192    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
193        Rill for the patch.
194    
195    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
196    
197    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
198    
199    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
200        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
201        was enabled.
202    
203    35. Improve JIT code generation for greedy plus quantifier.
204    
205    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
206        1 to "aa" instead of to an empty string. The bug affected repeated groups
207        that could potentially match an empty string.
208    
209    37. Optimizing single character iterators in JIT.
210    
211    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
212        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
213        codepoints that are too big for the mode are faulted, and in a UTF mode,
214        disallowed codepoints are also faulted.
215    
216    39. If PCRE was compiled with UTF support, in three places in the DFA
217        matcher there was code that should only have been obeyed in UTF mode, but
218        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
219        processing when bytes with values greater than 127 were present. In 16-bit
220        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
221        both cases the values are those that cannot be the first data item in a UTF
222        character. The three items that might have provoked this were recursions,
223        possessively repeated groups, and atomic groups.
224    
225    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
226        and pcregrep, because some OS require shared objects to be explicitly
227        passed to ld, causing the link step to fail if they are not.
228    
229    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
230        mode, patterns that started with \h* or \R* might be incorrectly matched.
231    
232    
233    Version 8.30 04-February-2012
234    -----------------------------
235    
236    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
237        name is defined in ctype.h.
238    
239    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
240        only in quite long subpatterns.
241    
242    3.  Removed the function pcre_info(), which has been obsolete and deprecated
243        since it was replaced by pcre_fullinfo() in February 2000.
244    
245    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
246        match a (*MARK), and the match failed at the start of the subject, a
247        reference to memory before the start of the subject could occur. This bug
248        was introduced by fix 17 of release 8.21.
249    
250    5.  A reference to an unset group with zero minimum repetition was giving
251        totally wrong answers (in non-JavaScript-compatibility mode). For example,
252        /(another)?(\1?)test/ matched against "hello world test". This bug was
253        introduced in release 8.13.
254    
255    6.  Add support for 16-bit character strings (a large amount of work involving
256        many changes and refactorings).
257    
258    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
259        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
260        from a file.
261    
262    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
263        rounding is not applied in this particular case).
264    
265    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
266        if they appear, or are escaped, in patterns.
267    
268    10. Get rid of a number of -Wunused-but-set-variable warnings.
269    
270    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
271        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
272        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
273        also returns the mark "x". This bug applied to capturing parentheses,
274        non-capturing parentheses, and atomic parentheses. It also applied to some
275        assertions.
276    
277    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
278        information out of configure.ac instead of relying on pcre.h.generic, which
279        is not stored in the repository.
280    
281    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
282        -lreadline.
283    
284    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
285    
286    15. Applied Graycode's patch to put the top-level frame on the stack rather
287        than the heap when not using the stack for recursion. This gives a
288        performance improvement in many cases when recursion is not deep.
289    
290    16. Experimental code added to "pcretest -C" to output the stack frame size.
291    
292    
293    Version 8.21 12-Dec-2011
294    ------------------------
295    
296    1.  Updating the JIT compiler.
297    
298    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
299        are added as well.
300    
301    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
302        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
303        calling _pcre_jit_exec. Some extra comments are added.
304    
305    4.  (*MARK) settings inside atomic groups that do not contain any capturing
306        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
307        was introduced by change 18 for 8.20.
308    
309    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
310        ECMA-262 standard.
311    
312    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
313        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
314        This bug was probably introduced by change 9 of 8.13.
315    
316    7.  While fixing 6 above, I noticed that a number of other items were being
317        incorrectly rejected as "not fixed length". This arose partly because newer
318        opcodes had not been added to the fixed-length checking code. I have (a)
319        corrected the bug and added tests for these items, and (b) arranged for an
320        error to occur if an unknown opcode is encountered while checking for fixed
321        length instead of just assuming "not fixed length". The items that were
322        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
323        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
324        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
325    
326    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
327        being incorrectly compiled and would have given unpredicatble results.
328    
329    9.  A possessively repeated subpattern with minimum repeat count greater than
330        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
331        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
332        the first (A) could occur when it should not.
333    
334    10. Add a cast and remove a redundant test from the code.
335    
336    11. JIT should use pcre_malloc/pcre_free for allocation.
337    
338    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
339        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
340        is anything other than /usr, -L is still shown).
341    
342    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
343    
344    14. Perl does not support \N without a following name in a [] class; PCRE now
345        also gives an error.
346    
347    15. If a forward reference was repeated with an upper limit of around 2000,
348        it caused the error "internal error: overran compiling workspace". The
349        maximum number of forward references (including repeats) was limited by the
350        internal workspace, and dependent on the LINK_SIZE. The code has been
351        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
352        the default depends on LINK_SIZE. There is a new upper limit (for safety)
353        of around 200,000 forward references. While doing this, I also speeded up
354        the filling in of repeated forward references.
355    
356    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
357        incorrectly expecting the subject to contain another "a" after the start.
358    
359    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
360        in the match, the SKIP should be ignored. This was not happening; instead
361        the SKIP was being treated as NOMATCH. For patterns such as
362        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
363        tested.
364    
365    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
366        now much more compatible with Perl, in particular in cases where the result
367        is a non-match for a non-anchored pattern. For example, if
368        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
369        "m", where previously it did not return a name. A side effect of this
370        change is that for partial matches, the last encountered mark name is
371        returned, as for non matches. A number of tests that were previously not
372        Perl-compatible have been moved into the Perl-compatible test files. The
373        refactoring has had the pleasing side effect of removing one argument from
374        the match() function, thus reducing its stack requirements.
375    
376    19. If the /S+ option was used in pcretest to study a pattern using JIT,
377        subsequent uses of /S (without +) incorrectly behaved like /S+.
378    
379    21. Retrieve executable code size support for the JIT compiler and fixing
380        some warnings.
381    
382    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
383        not work when the shorter character appeared right at the end of the
384        subject string.
385    
386    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
387        systems.
388    
389    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
390        output it when the /M option is used in pcretest.
391    
392    25. The CheckMan script was not being included in the distribution. Also, added
393        an explicit "perl" to run Perl scripts from the PrepareRelease script
394        because this is reportedly needed in Windows.
395    
396    26. If study data was being save in a file and studying had not found a set of
397        "starts with" bytes for the pattern, the data written to the file (though
398        never used) was taken from uninitialized memory and so caused valgrind to
399        complain.
400    
401    27. Updated RunTest.bat as provided by Sheri Pierce.
402    
403    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
404    
405    29. Computation of memory usage for the table of capturing group names was
406        giving an unnecessarily large value.
407    
408    
409    Version 8.20 21-Oct-2011
410    ------------------------
411    
412    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
413        a POSIX class. After further experiments with Perl, which convinced me that
414        Perl has bugs and confusions, a closing square bracket is no longer allowed
415        in a POSIX name. This bug also affected patterns with classes that started
416        with full stops.
417    
418    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
419        captured substring, but while checking the failing first alternative,
420        substring 1 is temporarily captured. If the output vector supplied to
421        pcre_exec() was not big enough for this capture, the yield of the function
422        was still zero ("insufficient space for captured substrings"). This cannot
423        be totally fixed without adding another stack variable, which seems a lot
424        of expense for a edge case. However, I have improved the situation in cases
425        such as /(a)(b)x|abc/ matched against "abc", where the return code
426        indicates that fewer than the maximum number of slots in the ovector have
427        been set.
428    
429    3.  Related to (2) above: when there are more back references in a pattern than
430        slots in the output vector, pcre_exec() uses temporary memory during
431        matching, and copies in the captures as far as possible afterwards. It was
432        using the entire output vector, but this conflicts with the specification
433        that only 2/3 is used for passing back captured substrings. Now it uses
434        only the first 2/3, for compatibility. This is, of course, another edge
435        case.
436    
437    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
438        main code base, and can be used by building with --enable-jit. When this is
439        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
440        runtime --no-jit option is given.
441    
442    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
443        ovector, the return from the function was zero, implying that there were
444        other matches that did not fit. The correct "exactly full" value is now
445        returned.
446    
447    6.  If a subpattern that was called recursively or as a subroutine contained
448        (*PRUNE) or any other control that caused it to give a non-standard return,
449        invalid errors such as "Error -26 (nested recursion at the same subject
450        position)" or even infinite loops could occur.
451    
452    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
453        computing the minimum length on reaching *ACCEPT, and so ended up with the
454        wrong value of 1 rather than 0. Further investigation indicates that
455        computing a minimum subject length in the presence of *ACCEPT is difficult
456        (think back references, subroutine calls), and so I have changed the code
457        so that no minimum is registered for a pattern that contains *ACCEPT.
458    
459    8.  If (*THEN) was present in the first (true) branch of a conditional group,
460        it was not handled as intended. [But see 16 below.]
461    
462    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
463        Sheri Pierce.
464    
465    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
466        the first byte in a match must be "a".
467    
468    11. Change 17 for 8.13 increased the recursion depth for patterns like
469        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
470        pattern contains any instances of (*THEN). If it does not, the old
471        optimizations are restored. It would be nice to do this on a per-group
472        basis, but at the moment that is not feasible.
473    
474    12. In some environments, the output of pcretest -C is CRLF terminated. This
475        broke RunTest's code that checks for the link size. A single white space
476        character after the value is now allowed for.
477    
478    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
479        For "fr", it uses the Windows-specific input and output files.
480    
481    14. If (*THEN) appeared in a group that was called recursively or as a
482        subroutine, it did not work as intended. [But see next item.]
483    
484    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
485        pattern fragments (but not containing any | characters). If A and B are
486        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
487        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
488        D. In other words, Perl considers parentheses that do not contain any |
489        characters to be part of a surrounding alternative, whereas PCRE was
490        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
491        differently. PCRE now behaves in the same way as Perl, except in the case
492        of subroutine/recursion calls such as (?1) which have in any case always
493        been different (but PCRE had them first :-).
494    
495    16. Related to 15 above: Perl does not treat the | in a conditional group as
496        creating alternatives. Such a group is treated in the same way as an
497        ordinary group without any | characters when processing (*THEN). PCRE has
498        been changed to match Perl's behaviour.
499    
500    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
501        RunGrepTest script failed.
502    
503    18. Change 22 for version 13 caused atomic groups to use more stack. This is
504        inevitable for groups that contain captures, but it can lead to a lot of
505        stack use in large patterns. The old behaviour has been restored for atomic
506        groups that do not contain any capturing parentheses.
507    
508    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
509        suppress the check for a minimum subject length at run time. (If it was
510        given to pcre_exec() or pcre_dfa_exec() it did work.)
511    
512    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
513        fail to work when decoding hex characters in data strings in EBCDIC
514        environments.
515    
516    21. It appears that in at least one Mac OS environment, the isxdigit() function
517        is implemented as a macro that evaluates to its argument more than once,
518        contravening the C 90 Standard (I haven't checked a later standard). There
519        was an instance in pcretest which caused it to go wrong when processing
520        \x{...} escapes in subject strings. The has been rewritten to avoid using
521        things like p++ in the argument of isxdigit().
522    
523    
524    Version 8.13 16-Aug-2011
525  ------------------------  ------------------------
526    
527  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 20  Version 8.13 30-Apr-2011 Line 540  Version 8.13 30-Apr-2011
540      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
541      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
542      left).      left).
543    
544  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
545      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
546      as the output vector has at least 2 elements. The offset of the start of      as the output vector has at least 2 elements. The offset of the start of
547      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
548    
549  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
550      now returned is for the first byte of the failing character, instead of the      now returned is for the first byte of the failing character, instead of the
551      last byte inspected. This is an incompatible change, but I hope it is small      last byte inspected. This is an incompatible change, but I hope it is small
552      enough not to be a problem. It makes the returned offset consistent with      enough not to be a problem. It makes the returned offset consistent with
553      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
554    
555  7.  pcretest now gives a text phrase as well as the error number when  7.  pcretest now gives a text phrase as well as the error number when
556      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
557      failure, the offset and reason code are output.      failure, the offset and reason code are output.
558    
559  8.  When \R was used with a maximizing quantifier it failed to skip backwards  8.  When \R was used with a maximizing quantifier it failed to skip backwards
560      over a \r\n pair if the subsequent match failed. Instead, it just skipped      over a \r\n pair if the subsequent match failed. Instead, it just skipped
561      back over a single character (\n). This seems wrong (because it treated the      back over a single character (\n). This seems wrong (because it treated the
562      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
563      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
564      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
565      has been changed.      has been changed.
566    
567  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
568      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
569      time (the PCRE_DOTALL option was changed this way some time ago: version      time (the PCRE_DOTALL option was changed this way some time ago: version
570      7.7 change 16). This has made it possible to abolish the OP_OPT op code,      7.7 change 16). This has made it possible to abolish the OP_OPT op code,
571      which was always a bit of a fudge. It also means that there is one less      which was always a bit of a fudge. It also means that there is one less
572      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
573      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
574      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
575    
576  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
577      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
578      using pcre_exec().      using pcre_exec().
579    
580  11. While implementing 10, a number of bugs in the handling of groups were  11. While implementing 10, a number of bugs in the handling of groups were
581      discovered and fixed:      discovered and fixed:
582    
583      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
584      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
585      ((a|)+)+  did not notice that the outer group could match an empty string.      ((a|)+)+  did not notice that the outer group could match an empty string.
586      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
587      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
588    
589  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
590      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
591      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
592    
593  13. Be more explicit in pcre_study() instead of relying on "default" for  13. Be more explicit in pcre_study() instead of relying on "default" for
594      opcodes that mean there is no starting character; this means that when new      opcodes that mean there is no starting character; this means that when new
595      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
596      pick them up.      pick them up.
597    
598  14. The -s option of pcretest has been documented for ages as being an old  14. The -s option of pcretest has been documented for ages as being an old
599      synonym of -m (show memory usage). I have changed it to mean "force study      synonym of -m (show memory usage). I have changed it to mean "force study
600      for every regex", that is, assume /S for every regex. This is similar to -i      for every regex", that is, assume /S for every regex. This is similar to -i
601      and -d etc. It's slightly incompatible, but I'm hoping nobody is still      and -d etc. It's slightly incompatible, but I'm hoping nobody is still
602      using it. It makes it easier to run collection of tests with study enabled,      using it. It makes it easier to run collections of tests with and without
603      and thereby test pcre_study() more easily.      study enabled, and thereby test pcre_study() more easily. All the standard
604        tests are now run with and without -s (but some patterns can be marked as
605        "never study" - see 20 below).
606    
607  15. When (*ACCEPT) was used in a subpattern that was called recursively, the  15. When (*ACCEPT) was used in a subpattern that was called recursively, the
608      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
609      correctly.      correctly.
610    
611  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
612      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
613      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
614      match.      match.
615    
616    17. There was optimizing code for the last branch of non-capturing parentheses,
617        and also for the obeyed branch of a conditional subexpression, which used
618        tail recursion to cut down on stack usage. Unfortunately, now that there is
619        the possibility of (*THEN) occurring in these branches, tail recursion is
620        no longer possible because the return has to be checked for (*THEN). These
621        two optimizations have therefore been removed. [But see 8.20/11 above.]
622    
623    18. If a pattern containing \R was studied, it was assumed that \R always
624        matched two bytes, thus causing the minimum subject length to be
625        incorrectly computed because \R can also match just one byte.
626    
627    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
628        was incorrectly computed.
629    
630    20. If /S is present twice on a test pattern in pcretest input, it now
631        *disables* studying, thereby overriding the use of -s on the command line
632        (see 14 above). This is necessary for one or two tests to keep the output
633        identical in both cases.
634    
635    21. When (*ACCEPT) was used in an assertion that matched an empty string and
636        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
637    
638    22. When an atomic group that contained a capturing parenthesis was
639        successfully matched, but the branch in which it appeared failed, the
640        capturing was not being forgotten if a higher numbered group was later
641        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
642        group 1 to "a", when in fact it should be unset. This applied to multi-
643        branched capturing and non-capturing groups, repeated or not, and also to
644        positive assertions (capturing in negative assertions does not happen
645        in PCRE) and also to nested atomic groups.
646    
647    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
648        subject after a captured substring, to make it easier to tell which of a
649        number of identical substrings has been captured.
650    
651    24. The way atomic groups are processed by pcre_exec() has been changed so that
652        if they are repeated, backtracking one repetition now resets captured
653        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
654        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
655        "aaa". Previously, it would have been "a". As part of this code
656        refactoring, the way recursive calls are handled has also been changed.
657    
658    25. If an assertion condition captured any substrings, they were not passed
659        back unless some other capturing happened later. For example, if
660        (?(?=(a))a) was matched against "a", no capturing was returned.
661    
662    26. When studying a pattern that contained subroutine calls or assertions,
663        the code for finding the minimum length of a possible match was handling
664        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
665        group 1 called group 2 while simultaneously a separate group 2 called group
666        1). A stack overflow occurred in this case. I have fixed this by limiting
667        the recursion depth to 10.
668    
669    27. Updated RunTest.bat in the distribution to the version supplied by Tom
670        Fortmann. This supports explicit test numbers on the command line, and has
671        argument validation and error reporting.
672    
673    28. An instance of \X with an unlimited repeat could fail if at any point the
674        first character it looked at was a mark character.
675    
676    29. Some minor code refactoring concerning Unicode properties and scripts
677        should reduce the stack requirement of match() slightly.
678    
679    30. Added the '=' option to pcretest to check the setting of unused capturing
680        slots at the end of the pattern, which are documented as being -1, but are
681        not included in the return count.
682    
683    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
684        compiled something random. Now it gives a compile-time error (as does
685        Perl).
686    
687    32. A *MARK encountered during the processing of a positive assertion is now
688        recorded and passed back (compatible with Perl).
689    
690    33. If --only-matching or --colour was set on a pcregrep call whose pattern
691        had alternative anchored branches, the search for a second match in a line
692        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
693        matched the line "0102" twice. The same bug affected patterns that started
694        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
695        twice.
696    
697    34. Previously, PCRE did not allow quantification of assertions. However, Perl
698        does, and because of capturing effects, quantifying parenthesized
699        assertions may at times be useful. Quantifiers are now allowed for
700        parenthesized assertions.
701    
702    35. A minor code tidy in pcre_compile() when checking options for \R usage.
703    
704    36. \g was being checked for fancy things in a character class, when it should
705        just be a literal "g".
706    
707    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
708        appearance of a nested POSIX class supersedes an apparent external class.
709        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
710        unescaped square brackets may also appear as part of class names. For
711        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
712        more like Perl. (But see 8.20/1 above.)
713    
714    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
715        was because it thought it was \N{name}, which is not supported).
716    
717    39. Add minix to OS list not supporting the -S option in pcretest.
718    
719    40. PCRE tries to detect cases of infinite recursion at compile time, but it
720        cannot analyze patterns in sufficient detail to catch mutual recursions
721        such as ((?1))((?2)). There is now a runtime test that gives an error if a
722        subgroup is called recursively as a subpattern for a second time at the
723        same position in the subject string. In previous releases this might have
724        been caught by the recursion limit, or it might have run out of stack.
725    
726    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
727        happen only once. PCRE was, however incorrectly giving a compile time error
728        "recursive call could loop indefinitely" because it cannot analyze the
729        pattern in sufficient detail. The compile time test no longer happens when
730        PCRE is compiling a conditional subpattern, but actual runaway loops are
731        now caught at runtime (see 40 above).
732    
733    42. It seems that Perl allows any characters other than a closing parenthesis
734        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
735        has been changed to be the same.
736    
737    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
738        as not to get warnings when autogen.sh is called. Also changed
739        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
740    
741    44. To help people who use pcregrep to scan files containing exceedingly long
742        lines, the following changes have been made:
743    
744        (a) The default value of the buffer size parameter has been increased from
745            8K to 20K. (The actual buffer used is three times this size.)
746    
747        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
748            PCRE is built.
749    
750        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
751            to be set at run time.
752    
753        (d) Numerical values in pcregrep options can be followed by K or M, for
754            example --buffer-size=50K.
755    
756        (e) If a line being scanned overflows pcregrep's buffer, an error is now
757            given and the return code is set to 2.
758    
759    45. Add a pointer to the latest mark to the callout data block.
760    
761    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
762        partial match of an empty string instead of no match. This was specific to
763        the use of ".".
764    
765    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
766        complete match instead of a partial match. This bug was dependent on both
767        the PCRE_UTF8 and PCRE_DOTALL options being set.
768    
769    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
770        starting byte set, because \b was not being ignored.
771    
772    
773  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
774  ------------------------  ------------------------

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