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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.11 24-Nov-2010  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    
75    
76    Version 8.31 06-July-2012
77    -------------------------
78    
79    1.  Fixing a wrong JIT test case and some compiler warnings.
80    
81    2.  Removed a bashism from the RunTest script.
82    
83    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
84        to unsigned type, result still unsigned" that was given by an MS compiler
85        on encountering the code "-sizeof(xxx)".
86    
87    4.  Partial matching support is added to the JIT compiler.
88    
89    5.  Fixed several bugs concerned with partial matching of items that consist
90        of more than one character:
91    
92        (a) /^(..)\1/ did not partially match "aba" because checking references was
93            done on an "all or nothing" basis. This also applied to repeated
94            references.
95    
96        (b) \R did not give a hard partial match if \r was found at the end of the
97            subject.
98    
99        (c) \X did not give a hard partial match after matching one or more
100            characters at the end of the subject.
101    
102        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
103            a partial match for the string "\r".
104    
105        (e) When newline was set to CRLF, the metacharacter "." did not recognize
106            a partial match for a CR character at the end of the subject string.
107    
108    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
109        running pcretest, the text "(JIT)" added to the output whenever JIT is
110        actually used to run the match.
111    
112    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
113        or /S+[+] with a digit between 1 and 7.
114    
115    8.  OP_NOT now supports any UTF character not just single-byte ones.
116    
117    9.  (*MARK) control verb is now supported by the JIT compiler.
118    
119    10. The command "./RunTest list" lists the available tests without actually
120        running any of them. (Because I keep forgetting what they all are.)
121    
122    11. Add PCRE_INFO_MAXLOOKBEHIND.
123    
124    12. Applied a (slightly modified) user-supplied patch that improves performance
125        when the heap is used for recursion (compiled with --disable-stack-for-
126        recursion). Instead of malloc and free for each heap frame each time a
127        logical recursion happens, frames are retained on a chain and re-used where
128        possible. This sometimes gives as much as 30% improvement.
129    
130    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
131        call.
132    
133    14. As documented, (*COMMIT) is now confined to within a positive assertion.
134    
135    15. It is now possible to link pcretest with libedit as an alternative to
136        libreadline.
137    
138    16. (*COMMIT) control verb is now supported by the JIT compiler.
139    
140    17. The Unicode data tables have been updated to Unicode 6.1.0.
141    
142    18. Added --file-list option to pcregrep.
143    
144    19. Added binary file support to pcregrep, including the -a, --binary-files,
145        -I, and --text options.
146    
147    20. The madvise function is renamed for posix_madvise for QNX compatibility
148        reasons. Fixed by Giuseppe D'Angelo.
149    
150    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
151    
152    22. Changed the option for creating symbolic links for 16-bit man pages from
153        -s to -sf so that re-installing does not cause issues.
154    
155    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
156    
157    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
158        matches in certain environments (the workspace was not being correctly
159        retained). Also added to pcre_dfa_exec() a simple plausibility check on
160        some of the workspace data at the beginning of a restart.
161    
162    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
163        was not doing so when it should - probably a typo introduced by SVN 528
164        (change 8.10/14).
165    
166    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
167        \w+ when the character tables indicated that \x{c4} was a word character.
168        There were several related cases, all because the tests for doing a table
169        lookup were testing for characters less than 127 instead of 255.
170    
171    27. If a pattern contains capturing parentheses that are not used in a match,
172        their slots in the ovector are set to -1. For those that are higher than
173        any matched groups, this happens at the end of processing. In the case when
174        there were back references that the ovector was too small to contain
175        (causing temporary malloc'd memory to be used during matching), and the
176        highest capturing number was not used, memory off the end of the ovector
177        was incorrectly being set to -1. (It was using the size of the temporary
178        memory instead of the true size.)
179    
180    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
181        ovector size, it uses memory at the end of the block that it has got.
182    
183    29. Check for an overlong MARK name and give an error at compile time. The
184        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
185    
186    30. JIT compiler update.
187    
188    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
189        Rill for the patch.
190    
191    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
192    
193    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
194    
195    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
196        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
197        was enabled.
198    
199    35. Improve JIT code generation for greedy plus quantifier.
200    
201    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
202        1 to "aa" instead of to an empty string. The bug affected repeated groups
203        that could potentially match an empty string.
204    
205    37. Optimizing single character iterators in JIT.
206    
207    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
208        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
209        codepoints that are too big for the mode are faulted, and in a UTF mode,
210        disallowed codepoints are also faulted.
211    
212    39. If PCRE was compiled with UTF support, in three places in the DFA
213        matcher there was code that should only have been obeyed in UTF mode, but
214        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
215        processing when bytes with values greater than 127 were present. In 16-bit
216        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
217        both cases the values are those that cannot be the first data item in a UTF
218        character. The three items that might have provoked this were recursions,
219        possessively repeated groups, and atomic groups.
220    
221    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
222        and pcregrep, because some OS require shared objects to be explicitly
223        passed to ld, causing the link step to fail if they are not.
224    
225    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
226        mode, patterns that started with \h* or \R* might be incorrectly matched.
227    
228    
229    Version 8.30 04-February-2012
230    -----------------------------
231    
232    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
233        name is defined in ctype.h.
234    
235    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
236        only in quite long subpatterns.
237    
238    3.  Removed the function pcre_info(), which has been obsolete and deprecated
239        since it was replaced by pcre_fullinfo() in February 2000.
240    
241    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
242        match a (*MARK), and the match failed at the start of the subject, a
243        reference to memory before the start of the subject could occur. This bug
244        was introduced by fix 17 of release 8.21.
245    
246    5.  A reference to an unset group with zero minimum repetition was giving
247        totally wrong answers (in non-JavaScript-compatibility mode). For example,
248        /(another)?(\1?)test/ matched against "hello world test". This bug was
249        introduced in release 8.13.
250    
251    6.  Add support for 16-bit character strings (a large amount of work involving
252        many changes and refactorings).
253    
254    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
255        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
256        from a file.
257    
258    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
259        rounding is not applied in this particular case).
260    
261    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
262        if they appear, or are escaped, in patterns.
263    
264    10. Get rid of a number of -Wunused-but-set-variable warnings.
265    
266    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
267        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
268        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
269        also returns the mark "x". This bug applied to capturing parentheses,
270        non-capturing parentheses, and atomic parentheses. It also applied to some
271        assertions.
272    
273    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
274        information out of configure.ac instead of relying on pcre.h.generic, which
275        is not stored in the repository.
276    
277    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
278        -lreadline.
279    
280    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
281    
282    15. Applied Graycode's patch to put the top-level frame on the stack rather
283        than the heap when not using the stack for recursion. This gives a
284        performance improvement in many cases when recursion is not deep.
285    
286    16. Experimental code added to "pcretest -C" to output the stack frame size.
287    
288    
289    Version 8.21 12-Dec-2011
290    ------------------------
291    
292    1.  Updating the JIT compiler.
293    
294    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
295        are added as well.
296    
297    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
298        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
299        calling _pcre_jit_exec. Some extra comments are added.
300    
301    4.  (*MARK) settings inside atomic groups that do not contain any capturing
302        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
303        was introduced by change 18 for 8.20.
304    
305    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
306        ECMA-262 standard.
307    
308    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
309        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
310        This bug was probably introduced by change 9 of 8.13.
311    
312    7.  While fixing 6 above, I noticed that a number of other items were being
313        incorrectly rejected as "not fixed length". This arose partly because newer
314        opcodes had not been added to the fixed-length checking code. I have (a)
315        corrected the bug and added tests for these items, and (b) arranged for an
316        error to occur if an unknown opcode is encountered while checking for fixed
317        length instead of just assuming "not fixed length". The items that were
318        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
319        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
320        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
321    
322    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
323        being incorrectly compiled and would have given unpredicatble results.
324    
325    9.  A possessively repeated subpattern with minimum repeat count greater than
326        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
327        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
328        the first (A) could occur when it should not.
329    
330    10. Add a cast and remove a redundant test from the code.
331    
332    11. JIT should use pcre_malloc/pcre_free for allocation.
333    
334    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
335        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
336        is anything other than /usr, -L is still shown).
337    
338    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
339    
340    14. Perl does not support \N without a following name in a [] class; PCRE now
341        also gives an error.
342    
343    15. If a forward reference was repeated with an upper limit of around 2000,
344        it caused the error "internal error: overran compiling workspace". The
345        maximum number of forward references (including repeats) was limited by the
346        internal workspace, and dependent on the LINK_SIZE. The code has been
347        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
348        the default depends on LINK_SIZE. There is a new upper limit (for safety)
349        of around 200,000 forward references. While doing this, I also speeded up
350        the filling in of repeated forward references.
351    
352    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
353        incorrectly expecting the subject to contain another "a" after the start.
354    
355    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
356        in the match, the SKIP should be ignored. This was not happening; instead
357        the SKIP was being treated as NOMATCH. For patterns such as
358        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
359        tested.
360    
361    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
362        now much more compatible with Perl, in particular in cases where the result
363        is a non-match for a non-anchored pattern. For example, if
364        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
365        "m", where previously it did not return a name. A side effect of this
366        change is that for partial matches, the last encountered mark name is
367        returned, as for non matches. A number of tests that were previously not
368        Perl-compatible have been moved into the Perl-compatible test files. The
369        refactoring has had the pleasing side effect of removing one argument from
370        the match() function, thus reducing its stack requirements.
371    
372    19. If the /S+ option was used in pcretest to study a pattern using JIT,
373        subsequent uses of /S (without +) incorrectly behaved like /S+.
374    
375    21. Retrieve executable code size support for the JIT compiler and fixing
376        some warnings.
377    
378    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
379        not work when the shorter character appeared right at the end of the
380        subject string.
381    
382    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
383        systems.
384    
385    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
386        output it when the /M option is used in pcretest.
387    
388    25. The CheckMan script was not being included in the distribution. Also, added
389        an explicit "perl" to run Perl scripts from the PrepareRelease script
390        because this is reportedly needed in Windows.
391    
392    26. If study data was being save in a file and studying had not found a set of
393        "starts with" bytes for the pattern, the data written to the file (though
394        never used) was taken from uninitialized memory and so caused valgrind to
395        complain.
396    
397    27. Updated RunTest.bat as provided by Sheri Pierce.
398    
399    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
400    
401    29. Computation of memory usage for the table of capturing group names was
402        giving an unnecessarily large value.
403    
404    
405    Version 8.20 21-Oct-2011
406    ------------------------
407    
408    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
409        a POSIX class. After further experiments with Perl, which convinced me that
410        Perl has bugs and confusions, a closing square bracket is no longer allowed
411        in a POSIX name. This bug also affected patterns with classes that started
412        with full stops.
413    
414    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
415        captured substring, but while checking the failing first alternative,
416        substring 1 is temporarily captured. If the output vector supplied to
417        pcre_exec() was not big enough for this capture, the yield of the function
418        was still zero ("insufficient space for captured substrings"). This cannot
419        be totally fixed without adding another stack variable, which seems a lot
420        of expense for a edge case. However, I have improved the situation in cases
421        such as /(a)(b)x|abc/ matched against "abc", where the return code
422        indicates that fewer than the maximum number of slots in the ovector have
423        been set.
424    
425    3.  Related to (2) above: when there are more back references in a pattern than
426        slots in the output vector, pcre_exec() uses temporary memory during
427        matching, and copies in the captures as far as possible afterwards. It was
428        using the entire output vector, but this conflicts with the specification
429        that only 2/3 is used for passing back captured substrings. Now it uses
430        only the first 2/3, for compatibility. This is, of course, another edge
431        case.
432    
433    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
434        main code base, and can be used by building with --enable-jit. When this is
435        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
436        runtime --no-jit option is given.
437    
438    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
439        ovector, the return from the function was zero, implying that there were
440        other matches that did not fit. The correct "exactly full" value is now
441        returned.
442    
443    6.  If a subpattern that was called recursively or as a subroutine contained
444        (*PRUNE) or any other control that caused it to give a non-standard return,
445        invalid errors such as "Error -26 (nested recursion at the same subject
446        position)" or even infinite loops could occur.
447    
448    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
449        computing the minimum length on reaching *ACCEPT, and so ended up with the
450        wrong value of 1 rather than 0. Further investigation indicates that
451        computing a minimum subject length in the presence of *ACCEPT is difficult
452        (think back references, subroutine calls), and so I have changed the code
453        so that no minimum is registered for a pattern that contains *ACCEPT.
454    
455    8.  If (*THEN) was present in the first (true) branch of a conditional group,
456        it was not handled as intended. [But see 16 below.]
457    
458    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
459        Sheri Pierce.
460    
461    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
462        the first byte in a match must be "a".
463    
464    11. Change 17 for 8.13 increased the recursion depth for patterns like
465        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
466        pattern contains any instances of (*THEN). If it does not, the old
467        optimizations are restored. It would be nice to do this on a per-group
468        basis, but at the moment that is not feasible.
469    
470    12. In some environments, the output of pcretest -C is CRLF terminated. This
471        broke RunTest's code that checks for the link size. A single white space
472        character after the value is now allowed for.
473    
474    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
475        For "fr", it uses the Windows-specific input and output files.
476    
477    14. If (*THEN) appeared in a group that was called recursively or as a
478        subroutine, it did not work as intended. [But see next item.]
479    
480    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
481        pattern fragments (but not containing any | characters). If A and B are
482        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
483        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
484        D. In other words, Perl considers parentheses that do not contain any |
485        characters to be part of a surrounding alternative, whereas PCRE was
486        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
487        differently. PCRE now behaves in the same way as Perl, except in the case
488        of subroutine/recursion calls such as (?1) which have in any case always
489        been different (but PCRE had them first :-).
490    
491    16. Related to 15 above: Perl does not treat the | in a conditional group as
492        creating alternatives. Such a group is treated in the same way as an
493        ordinary group without any | characters when processing (*THEN). PCRE has
494        been changed to match Perl's behaviour.
495    
496    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
497        RunGrepTest script failed.
498    
499    18. Change 22 for version 13 caused atomic groups to use more stack. This is
500        inevitable for groups that contain captures, but it can lead to a lot of
501        stack use in large patterns. The old behaviour has been restored for atomic
502        groups that do not contain any capturing parentheses.
503    
504    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
505        suppress the check for a minimum subject length at run time. (If it was
506        given to pcre_exec() or pcre_dfa_exec() it did work.)
507    
508    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
509        fail to work when decoding hex characters in data strings in EBCDIC
510        environments.
511    
512    21. It appears that in at least one Mac OS environment, the isxdigit() function
513        is implemented as a macro that evaluates to its argument more than once,
514        contravening the C 90 Standard (I haven't checked a later standard). There
515        was an instance in pcretest which caused it to go wrong when processing
516        \x{...} escapes in subject strings. The has been rewritten to avoid using
517        things like p++ in the argument of isxdigit().
518    
519    
520    Version 8.13 16-Aug-2011
521    ------------------------
522    
523    1.  The Unicode data tables have been updated to Unicode 6.0.0.
524    
525    2.  Two minor typos in pcre_internal.h have been fixed.
526    
527    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
528        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
529        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
530    
531    4.  There were a number of related bugs in the code for matching backrefences
532        caselessly in UTF-8 mode when codes for the characters concerned were
533        different numbers of bytes. For example, U+023A and U+2C65 are an upper
534        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
535        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
536        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
537        2-byte code at the end of the subject (it thought there wasn't enough data
538        left).
539    
540    5.  Comprehensive information about what went wrong is now returned by
541        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
542        as the output vector has at least 2 elements. The offset of the start of
543        the failing character and a reason code are placed in the vector.
544    
545    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
546        now returned is for the first byte of the failing character, instead of the
547        last byte inspected. This is an incompatible change, but I hope it is small
548        enough not to be a problem. It makes the returned offset consistent with
549        pcre_exec() and pcre_dfa_exec().
550    
551    7.  pcretest now gives a text phrase as well as the error number when
552        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
553        failure, the offset and reason code are output.
554    
555    8.  When \R was used with a maximizing quantifier it failed to skip backwards
556        over a \r\n pair if the subsequent match failed. Instead, it just skipped
557        back over a single character (\n). This seems wrong (because it treated the
558        two characters as a single entity when going forwards), conflicts with the
559        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
560        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
561        has been changed.
562    
563    9.  Some internal refactoring has changed the processing so that the handling
564        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
565        time (the PCRE_DOTALL option was changed this way some time ago: version
566        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
567        which was always a bit of a fudge. It also means that there is one less
568        argument for the match() function, which reduces its stack requirements
569        slightly. This change also fixes an incompatibility with Perl: the pattern
570        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
571    
572    10. More internal refactoring has drastically reduced the number of recursive
573        calls to match() for possessively repeated groups such as (abc)++ when
574        using pcre_exec().
575    
576    11. While implementing 10, a number of bugs in the handling of groups were
577        discovered and fixed:
578    
579        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
580        (a|)*(?1) gave a compile-time internal error.
581        ((a|)+)+  did not notice that the outer group could match an empty string.
582        (^a|^)+   was not marked as anchored.
583        (.*a|.*)+ was not marked as matching at start or after a newline.
584    
585    12. Yet more internal refactoring has removed another argument from the match()
586        function. Special calls to this function are now indicated by setting a
587        value in a variable in the "match data" data block.
588    
589    13. Be more explicit in pcre_study() instead of relying on "default" for
590        opcodes that mean there is no starting character; this means that when new
591        ones are added and accidentally left out of pcre_study(), testing should
592        pick them up.
593    
594    14. The -s option of pcretest has been documented for ages as being an old
595        synonym of -m (show memory usage). I have changed it to mean "force study
596        for every regex", that is, assume /S for every regex. This is similar to -i
597        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
598        using it. It makes it easier to run collections of tests with and without
599        study enabled, and thereby test pcre_study() more easily. All the standard
600        tests are now run with and without -s (but some patterns can be marked as
601        "never study" - see 20 below).
602    
603    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
604        restoration of the capturing data to the outer values was not happening
605        correctly.
606    
607    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
608        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
609        pattern had matched an empty string, and so incorrectly returned a no
610        match.
611    
612    17. There was optimizing code for the last branch of non-capturing parentheses,
613        and also for the obeyed branch of a conditional subexpression, which used
614        tail recursion to cut down on stack usage. Unfortunately, now that there is
615        the possibility of (*THEN) occurring in these branches, tail recursion is
616        no longer possible because the return has to be checked for (*THEN). These
617        two optimizations have therefore been removed. [But see 8.20/11 above.]
618    
619    18. If a pattern containing \R was studied, it was assumed that \R always
620        matched two bytes, thus causing the minimum subject length to be
621        incorrectly computed because \R can also match just one byte.
622    
623    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
624        was incorrectly computed.
625    
626    20. If /S is present twice on a test pattern in pcretest input, it now
627        *disables* studying, thereby overriding the use of -s on the command line
628        (see 14 above). This is necessary for one or two tests to keep the output
629        identical in both cases.
630    
631    21. When (*ACCEPT) was used in an assertion that matched an empty string and
632        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
633    
634    22. When an atomic group that contained a capturing parenthesis was
635        successfully matched, but the branch in which it appeared failed, the
636        capturing was not being forgotten if a higher numbered group was later
637        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
638        group 1 to "a", when in fact it should be unset. This applied to multi-
639        branched capturing and non-capturing groups, repeated or not, and also to
640        positive assertions (capturing in negative assertions does not happen
641        in PCRE) and also to nested atomic groups.
642    
643    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
644        subject after a captured substring, to make it easier to tell which of a
645        number of identical substrings has been captured.
646    
647    24. The way atomic groups are processed by pcre_exec() has been changed so that
648        if they are repeated, backtracking one repetition now resets captured
649        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
650        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
651        "aaa". Previously, it would have been "a". As part of this code
652        refactoring, the way recursive calls are handled has also been changed.
653    
654    25. If an assertion condition captured any substrings, they were not passed
655        back unless some other capturing happened later. For example, if
656        (?(?=(a))a) was matched against "a", no capturing was returned.
657    
658    26. When studying a pattern that contained subroutine calls or assertions,
659        the code for finding the minimum length of a possible match was handling
660        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
661        group 1 called group 2 while simultaneously a separate group 2 called group
662        1). A stack overflow occurred in this case. I have fixed this by limiting
663        the recursion depth to 10.
664    
665    27. Updated RunTest.bat in the distribution to the version supplied by Tom
666        Fortmann. This supports explicit test numbers on the command line, and has
667        argument validation and error reporting.
668    
669    28. An instance of \X with an unlimited repeat could fail if at any point the
670        first character it looked at was a mark character.
671    
672    29. Some minor code refactoring concerning Unicode properties and scripts
673        should reduce the stack requirement of match() slightly.
674    
675    30. Added the '=' option to pcretest to check the setting of unused capturing
676        slots at the end of the pattern, which are documented as being -1, but are
677        not included in the return count.
678    
679    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
680        compiled something random. Now it gives a compile-time error (as does
681        Perl).
682    
683    32. A *MARK encountered during the processing of a positive assertion is now
684        recorded and passed back (compatible with Perl).
685    
686    33. If --only-matching or --colour was set on a pcregrep call whose pattern
687        had alternative anchored branches, the search for a second match in a line
688        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
689        matched the line "0102" twice. The same bug affected patterns that started
690        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
691        twice.
692    
693    34. Previously, PCRE did not allow quantification of assertions. However, Perl
694        does, and because of capturing effects, quantifying parenthesized
695        assertions may at times be useful. Quantifiers are now allowed for
696        parenthesized assertions.
697    
698    35. A minor code tidy in pcre_compile() when checking options for \R usage.
699    
700    36. \g was being checked for fancy things in a character class, when it should
701        just be a literal "g".
702    
703    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
704        appearance of a nested POSIX class supersedes an apparent external class.
705        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
706        unescaped square brackets may also appear as part of class names. For
707        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
708        more like Perl. (But see 8.20/1 above.)
709    
710    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
711        was because it thought it was \N{name}, which is not supported).
712    
713    39. Add minix to OS list not supporting the -S option in pcretest.
714    
715    40. PCRE tries to detect cases of infinite recursion at compile time, but it
716        cannot analyze patterns in sufficient detail to catch mutual recursions
717        such as ((?1))((?2)). There is now a runtime test that gives an error if a
718        subgroup is called recursively as a subpattern for a second time at the
719        same position in the subject string. In previous releases this might have
720        been caught by the recursion limit, or it might have run out of stack.
721    
722    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
723        happen only once. PCRE was, however incorrectly giving a compile time error
724        "recursive call could loop indefinitely" because it cannot analyze the
725        pattern in sufficient detail. The compile time test no longer happens when
726        PCRE is compiling a conditional subpattern, but actual runaway loops are
727        now caught at runtime (see 40 above).
728    
729    42. It seems that Perl allows any characters other than a closing parenthesis
730        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
731        has been changed to be the same.
732    
733    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
734        as not to get warnings when autogen.sh is called. Also changed
735        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
736    
737    44. To help people who use pcregrep to scan files containing exceedingly long
738        lines, the following changes have been made:
739    
740        (a) The default value of the buffer size parameter has been increased from
741            8K to 20K. (The actual buffer used is three times this size.)
742    
743        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
744            PCRE is built.
745    
746        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
747            to be set at run time.
748    
749        (d) Numerical values in pcregrep options can be followed by K or M, for
750            example --buffer-size=50K.
751    
752        (e) If a line being scanned overflows pcregrep's buffer, an error is now
753            given and the return code is set to 2.
754    
755    45. Add a pointer to the latest mark to the callout data block.
756    
757    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
758        partial match of an empty string instead of no match. This was specific to
759        the use of ".".
760    
761    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
762        complete match instead of a partial match. This bug was dependent on both
763        the PCRE_UTF8 and PCRE_DOTALL options being set.
764    
765    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
766        starting byte set, because \b was not being ignored.
767    
768    
769    Version 8.12 15-Jan-2011
770    ------------------------
771    
772    1.  Fixed some typos in the markup of the man pages, and wrote a script that
773        checks for such things as part of the documentation building process.
774    
775    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
776        --match-limit and --recursion-limit options (added for 8.11). In
777        particular, this made one of the standard tests fail. (The integer value
778        went into the wrong half of a long int.)
779    
780    3.  If the --colour option was given to pcregrep with -v (invert match), it
781        did strange things, either producing crazy output, or crashing. It should,
782        of course, ignore a request for colour when reporting lines that do not
783        match.
784    
785    4.  Another pcregrep bug caused similar problems if --colour was specified with
786        -M (multiline) and the pattern match finished with a line ending.
787    
788    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
789        matched in multiline mode, the following line was shown as part of the
790        match. This seems wrong, so I have changed it.
791    
792    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
793        the check for further matches in the same line (so they could be coloured)
794        to overrun the end of the current line. If another match was found, it was
795        incorrectly shown (and then shown again when found in the next line).
796    
797    7.  If pcregrep was compiled under Windows, there was a reference to the
798        function pcregrep_exit() before it was defined. I am assuming this was
799        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
800        reported by a user. I've moved the definition above the reference.
801    
802    
803    Version 8.11 10-Dec-2010
804  ------------------------  ------------------------
805    
806  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
# Line 127  Version 8.11 24-Nov-2010 Line 926  Version 8.11 24-Nov-2010
926      memory required was incorrectly computed, leading to "Failed: internal      memory required was incorrectly computed, leading to "Failed: internal
927      error: code overflow". This has been fixed.      error: code overflow". This has been fixed.
928    
929    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
930        pcretest.c, to avoid build problems in some Borland environments.
931    
932    
933  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010
934  ------------------------  ------------------------

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