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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    
66    
67    Version 8.31 06-July-2012
68    -------------------------
69    
70    1.  Fixing a wrong JIT test case and some compiler warnings.
71    
72    2.  Removed a bashism from the RunTest script.
73    
74    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
75        to unsigned type, result still unsigned" that was given by an MS compiler
76        on encountering the code "-sizeof(xxx)".
77    
78    4.  Partial matching support is added to the JIT compiler.
79    
80    5.  Fixed several bugs concerned with partial matching of items that consist
81        of more than one character:
82    
83        (a) /^(..)\1/ did not partially match "aba" because checking references was
84            done on an "all or nothing" basis. This also applied to repeated
85            references.
86    
87        (b) \R did not give a hard partial match if \r was found at the end of the
88            subject.
89    
90        (c) \X did not give a hard partial match after matching one or more
91            characters at the end of the subject.
92    
93        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
94            a partial match for the string "\r".
95    
96        (e) When newline was set to CRLF, the metacharacter "." did not recognize
97            a partial match for a CR character at the end of the subject string.
98    
99    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
100        running pcretest, the text "(JIT)" added to the output whenever JIT is
101        actually used to run the match.
102    
103    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
104        or /S+[+] with a digit between 1 and 7.
105    
106    8.  OP_NOT now supports any UTF character not just single-byte ones.
107    
108    9.  (*MARK) control verb is now supported by the JIT compiler.
109    
110    10. The command "./RunTest list" lists the available tests without actually
111        running any of them. (Because I keep forgetting what they all are.)
112    
113    11. Add PCRE_INFO_MAXLOOKBEHIND.
114    
115    12. Applied a (slightly modified) user-supplied patch that improves performance
116        when the heap is used for recursion (compiled with --disable-stack-for-
117        recursion). Instead of malloc and free for each heap frame each time a
118        logical recursion happens, frames are retained on a chain and re-used where
119        possible. This sometimes gives as much as 30% improvement.
120    
121    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
122        call.
123    
124    14. As documented, (*COMMIT) is now confined to within a positive assertion.
125    
126    15. It is now possible to link pcretest with libedit as an alternative to
127        libreadline.
128    
129    16. (*COMMIT) control verb is now supported by the JIT compiler.
130    
131    17. The Unicode data tables have been updated to Unicode 6.1.0.
132    
133    18. Added --file-list option to pcregrep.
134    
135    19. Added binary file support to pcregrep, including the -a, --binary-files,
136        -I, and --text options.
137    
138    20. The madvise function is renamed for posix_madvise for QNX compatibility
139        reasons. Fixed by Giuseppe D'Angelo.
140    
141    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
142    
143    22. Changed the option for creating symbolic links for 16-bit man pages from
144        -s to -sf so that re-installing does not cause issues.
145    
146    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
147    
148    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
149        matches in certain environments (the workspace was not being correctly
150        retained). Also added to pcre_dfa_exec() a simple plausibility check on
151        some of the workspace data at the beginning of a restart.
152    
153    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
154        was not doing so when it should - probably a typo introduced by SVN 528
155        (change 8.10/14).
156    
157    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
158        \w+ when the character tables indicated that \x{c4} was a word character.
159        There were several related cases, all because the tests for doing a table
160        lookup were testing for characters less than 127 instead of 255.
161    
162    27. If a pattern contains capturing parentheses that are not used in a match,
163        their slots in the ovector are set to -1. For those that are higher than
164        any matched groups, this happens at the end of processing. In the case when
165        there were back references that the ovector was too small to contain
166        (causing temporary malloc'd memory to be used during matching), and the
167        highest capturing number was not used, memory off the end of the ovector
168        was incorrectly being set to -1. (It was using the size of the temporary
169        memory instead of the true size.)
170    
171    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
172        ovector size, it uses memory at the end of the block that it has got.
173    
174    29. Check for an overlong MARK name and give an error at compile time. The
175        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
176    
177    30. JIT compiler update.
178    
179    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
180        Rill for the patch.
181    
182    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
183    
184    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
185    
186    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
187        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
188        was enabled.
189    
190    35. Improve JIT code generation for greedy plus quantifier.
191    
192    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
193        1 to "aa" instead of to an empty string. The bug affected repeated groups
194        that could potentially match an empty string.
195    
196    37. Optimizing single character iterators in JIT.
197    
198    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
199        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
200        codepoints that are too big for the mode are faulted, and in a UTF mode,
201        disallowed codepoints are also faulted.
202    
203    39. If PCRE was compiled with UTF support, in three places in the DFA
204        matcher there was code that should only have been obeyed in UTF mode, but
205        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
206        processing when bytes with values greater than 127 were present. In 16-bit
207        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
208        both cases the values are those that cannot be the first data item in a UTF
209        character. The three items that might have provoked this were recursions,
210        possessively repeated groups, and atomic groups.
211    
212    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
213        and pcregrep, because some OS require shared objects to be explicitly
214        passed to ld, causing the link step to fail if they are not.
215    
216    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
217        mode, patterns that started with \h* or \R* might be incorrectly matched.
218    
219    
220    Version 8.30 04-February-2012
221    -----------------------------
222    
223    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
224        name is defined in ctype.h.
225    
226    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
227        only in quite long subpatterns.
228    
229    3.  Removed the function pcre_info(), which has been obsolete and deprecated
230        since it was replaced by pcre_fullinfo() in February 2000.
231    
232    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
233        match a (*MARK), and the match failed at the start of the subject, a
234        reference to memory before the start of the subject could occur. This bug
235        was introduced by fix 17 of release 8.21.
236    
237    5.  A reference to an unset group with zero minimum repetition was giving
238        totally wrong answers (in non-JavaScript-compatibility mode). For example,
239        /(another)?(\1?)test/ matched against "hello world test". This bug was
240        introduced in release 8.13.
241    
242    6.  Add support for 16-bit character strings (a large amount of work involving
243        many changes and refactorings).
244    
245    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
246        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
247        from a file.
248    
249    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
250        rounding is not applied in this particular case).
251    
252    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
253        if they appear, or are escaped, in patterns.
254    
255    10. Get rid of a number of -Wunused-but-set-variable warnings.
256    
257    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
258        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
259        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
260        also returns the mark "x". This bug applied to capturing parentheses,
261        non-capturing parentheses, and atomic parentheses. It also applied to some
262        assertions.
263    
264    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
265        information out of configure.ac instead of relying on pcre.h.generic, which
266        is not stored in the repository.
267    
268    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
269        -lreadline.
270    
271    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
272    
273    15. Applied Graycode's patch to put the top-level frame on the stack rather
274        than the heap when not using the stack for recursion. This gives a
275        performance improvement in many cases when recursion is not deep.
276    
277    16. Experimental code added to "pcretest -C" to output the stack frame size.
278    
279    
280    Version 8.21 12-Dec-2011
281    ------------------------
282    
283    1.  Updating the JIT compiler.
284    
285    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
286        are added as well.
287    
288    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
289        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
290        calling _pcre_jit_exec. Some extra comments are added.
291    
292    4.  (*MARK) settings inside atomic groups that do not contain any capturing
293        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
294        was introduced by change 18 for 8.20.
295    
296    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
297        ECMA-262 standard.
298    
299    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
300        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
301        This bug was probably introduced by change 9 of 8.13.
302    
303    7.  While fixing 6 above, I noticed that a number of other items were being
304        incorrectly rejected as "not fixed length". This arose partly because newer
305        opcodes had not been added to the fixed-length checking code. I have (a)
306        corrected the bug and added tests for these items, and (b) arranged for an
307        error to occur if an unknown opcode is encountered while checking for fixed
308        length instead of just assuming "not fixed length". The items that were
309        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
310        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
311        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
312    
313    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
314        being incorrectly compiled and would have given unpredicatble results.
315    
316    9.  A possessively repeated subpattern with minimum repeat count greater than
317        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
318        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
319        the first (A) could occur when it should not.
320    
321    10. Add a cast and remove a redundant test from the code.
322    
323    11. JIT should use pcre_malloc/pcre_free for allocation.
324    
325    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
326        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
327        is anything other than /usr, -L is still shown).
328    
329    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
330    
331    14. Perl does not support \N without a following name in a [] class; PCRE now
332        also gives an error.
333    
334    15. If a forward reference was repeated with an upper limit of around 2000,
335        it caused the error "internal error: overran compiling workspace". The
336        maximum number of forward references (including repeats) was limited by the
337        internal workspace, and dependent on the LINK_SIZE. The code has been
338        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
339        the default depends on LINK_SIZE. There is a new upper limit (for safety)
340        of around 200,000 forward references. While doing this, I also speeded up
341        the filling in of repeated forward references.
342    
343    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
344        incorrectly expecting the subject to contain another "a" after the start.
345    
346    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
347        in the match, the SKIP should be ignored. This was not happening; instead
348        the SKIP was being treated as NOMATCH. For patterns such as
349        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
350        tested.
351    
352    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
353        now much more compatible with Perl, in particular in cases where the result
354        is a non-match for a non-anchored pattern. For example, if
355        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
356        "m", where previously it did not return a name. A side effect of this
357        change is that for partial matches, the last encountered mark name is
358        returned, as for non matches. A number of tests that were previously not
359        Perl-compatible have been moved into the Perl-compatible test files. The
360        refactoring has had the pleasing side effect of removing one argument from
361        the match() function, thus reducing its stack requirements.
362    
363    19. If the /S+ option was used in pcretest to study a pattern using JIT,
364        subsequent uses of /S (without +) incorrectly behaved like /S+.
365    
366    21. Retrieve executable code size support for the JIT compiler and fixing
367        some warnings.
368    
369    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
370        not work when the shorter character appeared right at the end of the
371        subject string.
372    
373    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
374        systems.
375    
376    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
377        output it when the /M option is used in pcretest.
378    
379    25. The CheckMan script was not being included in the distribution. Also, added
380        an explicit "perl" to run Perl scripts from the PrepareRelease script
381        because this is reportedly needed in Windows.
382    
383    26. If study data was being save in a file and studying had not found a set of
384        "starts with" bytes for the pattern, the data written to the file (though
385        never used) was taken from uninitialized memory and so caused valgrind to
386        complain.
387    
388    27. Updated RunTest.bat as provided by Sheri Pierce.
389    
390    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
391    
392    29. Computation of memory usage for the table of capturing group names was
393        giving an unnecessarily large value.
394    
395    
396    Version 8.20 21-Oct-2011
397    ------------------------
398    
399    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
400        a POSIX class. After further experiments with Perl, which convinced me that
401        Perl has bugs and confusions, a closing square bracket is no longer allowed
402        in a POSIX name. This bug also affected patterns with classes that started
403        with full stops.
404    
405    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
406        captured substring, but while checking the failing first alternative,
407        substring 1 is temporarily captured. If the output vector supplied to
408        pcre_exec() was not big enough for this capture, the yield of the function
409        was still zero ("insufficient space for captured substrings"). This cannot
410        be totally fixed without adding another stack variable, which seems a lot
411        of expense for a edge case. However, I have improved the situation in cases
412        such as /(a)(b)x|abc/ matched against "abc", where the return code
413        indicates that fewer than the maximum number of slots in the ovector have
414        been set.
415    
416    3.  Related to (2) above: when there are more back references in a pattern than
417        slots in the output vector, pcre_exec() uses temporary memory during
418        matching, and copies in the captures as far as possible afterwards. It was
419        using the entire output vector, but this conflicts with the specification
420        that only 2/3 is used for passing back captured substrings. Now it uses
421        only the first 2/3, for compatibility. This is, of course, another edge
422        case.
423    
424    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
425        main code base, and can be used by building with --enable-jit. When this is
426        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
427        runtime --no-jit option is given.
428    
429    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
430        ovector, the return from the function was zero, implying that there were
431        other matches that did not fit. The correct "exactly full" value is now
432        returned.
433    
434    6.  If a subpattern that was called recursively or as a subroutine contained
435        (*PRUNE) or any other control that caused it to give a non-standard return,
436        invalid errors such as "Error -26 (nested recursion at the same subject
437        position)" or even infinite loops could occur.
438    
439    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
440        computing the minimum length on reaching *ACCEPT, and so ended up with the
441        wrong value of 1 rather than 0. Further investigation indicates that
442        computing a minimum subject length in the presence of *ACCEPT is difficult
443        (think back references, subroutine calls), and so I have changed the code
444        so that no minimum is registered for a pattern that contains *ACCEPT.
445    
446    8.  If (*THEN) was present in the first (true) branch of a conditional group,
447        it was not handled as intended. [But see 16 below.]
448    
449    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
450        Sheri Pierce.
451    
452    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
453        the first byte in a match must be "a".
454    
455    11. Change 17 for 8.13 increased the recursion depth for patterns like
456        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
457        pattern contains any instances of (*THEN). If it does not, the old
458        optimizations are restored. It would be nice to do this on a per-group
459        basis, but at the moment that is not feasible.
460    
461    12. In some environments, the output of pcretest -C is CRLF terminated. This
462        broke RunTest's code that checks for the link size. A single white space
463        character after the value is now allowed for.
464    
465    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
466        For "fr", it uses the Windows-specific input and output files.
467    
468    14. If (*THEN) appeared in a group that was called recursively or as a
469        subroutine, it did not work as intended. [But see next item.]
470    
471    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
472        pattern fragments (but not containing any | characters). If A and B are
473        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
474        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
475        D. In other words, Perl considers parentheses that do not contain any |
476        characters to be part of a surrounding alternative, whereas PCRE was
477        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
478        differently. PCRE now behaves in the same way as Perl, except in the case
479        of subroutine/recursion calls such as (?1) which have in any case always
480        been different (but PCRE had them first :-).
481    
482    16. Related to 15 above: Perl does not treat the | in a conditional group as
483        creating alternatives. Such a group is treated in the same way as an
484        ordinary group without any | characters when processing (*THEN). PCRE has
485        been changed to match Perl's behaviour.
486    
487    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
488        RunGrepTest script failed.
489    
490    18. Change 22 for version 13 caused atomic groups to use more stack. This is
491        inevitable for groups that contain captures, but it can lead to a lot of
492        stack use in large patterns. The old behaviour has been restored for atomic
493        groups that do not contain any capturing parentheses.
494    
495    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
496        suppress the check for a minimum subject length at run time. (If it was
497        given to pcre_exec() or pcre_dfa_exec() it did work.)
498    
499    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
500        fail to work when decoding hex characters in data strings in EBCDIC
501        environments.
502    
503    21. It appears that in at least one Mac OS environment, the isxdigit() function
504        is implemented as a macro that evaluates to its argument more than once,
505        contravening the C 90 Standard (I haven't checked a later standard). There
506        was an instance in pcretest which caused it to go wrong when processing
507        \x{...} escapes in subject strings. The has been rewritten to avoid using
508        things like p++ in the argument of isxdigit().
509    
510    
511    Version 8.13 16-Aug-2011
512  ------------------------  ------------------------
513    
514  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 527  Version 8.13 30-Apr-2011
527      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
528      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
529      left).      left).
530    
531  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
532      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
533      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
534      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
535    
536  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
537      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
538      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
539      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
540      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
541    
542  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
543      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
544      failure, the offset and reason code are output.      failure, the offset and reason code are output.
545    
546  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
547      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
548      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
549      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
550      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
551      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
552      has been changed.      has been changed.
553    
554  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
555      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
556      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
557      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,
558      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
559      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
560      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
561      (?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.
562    
563  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
564      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
565      using pcre_exec().      using pcre_exec().
566    
567  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
568      discovered and fixed:      discovered and fixed:
569    
570      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
571      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
572      ((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.
573      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
574      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
575    
576  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
577      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
578      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
579    
580  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
581      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
582      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
583      pick them up.      pick them up.
584    
585  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
586      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
587      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
588      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
589      using it. It makes it easier to run collections of tests with and without      using it. It makes it easier to run collections of tests with and without
590      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
591      tests are now run with and without -s (but some patterns can be marked as      tests are now run with and without -s (but some patterns can be marked as
592      "never study" - see 20 below).      "never study" - see 20 below).
593    
594  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
595      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
596      correctly.      correctly.
597    
598  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
599      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
600      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
601      match.      match.
602    
603  17. There was optimizing code for the last branch of non-capturing parentheses,  17. There was optimizing code for the last branch of non-capturing parentheses,
604      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
605      tail recursion to cut down on stack usage. Unfortunately, not that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
606      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
607      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
608      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
609    
610  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
611      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
612      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
613    
614  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
615      was incorrectly computed.      was incorrectly computed.
616    
617  20. If /S is present twice on a test pattern in pcretest input, it *disables*  20. If /S is present twice on a test pattern in pcretest input, it now
618      studying, thereby overriding the use of -s on the command line. This is      *disables* studying, thereby overriding the use of -s on the command line
619      necessary for one or two tests to keep the output identical in both cases.      (see 14 above). This is necessary for one or two tests to keep the output
620        identical in both cases.
621    
622  21. When (*ACCEPT) was used in an assertion that matched an empty string and  21. When (*ACCEPT) was used in an assertion that matched an empty string and
623      PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.      PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
624    
625  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
626      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
627      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
628      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
629      group 1 to "a", when in fact it should be unset. This applied to multi-      group 1 to "a", when in fact it should be unset. This applied to multi-
630      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
631      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
632      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
633    
634  23. Add the ++ qualifier feature to pcretest, to show the remainder of the  23. Add the ++ qualifier feature to pcretest, to show the remainder of the
635      subject after a captured substring (to make it easier to tell which of a      subject after a captured substring, to make it easier to tell which of a
636      number of identical substrings has been captured).      number of identical substrings has been captured.
637    
638  24. The way atomic groups are processed by pcre_exec() has been changed so that  24. The way atomic groups are processed by pcre_exec() has been changed so that
639      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
640      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
641      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
642      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
643      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
644    
645  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
646      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
647      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
648    
649  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
650      the code for finding the minimum length of a possible match was handling      the code for finding the minimum length of a possible match was handling
651      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
652      group 1 called group 2 while simultaneously a separate group 2 called group      group 1 called group 2 while simultaneously a separate group 2 called group
653      1). A stack overflow occurred in this case. I have fixed this by limiting      1). A stack overflow occurred in this case. I have fixed this by limiting
654      the recursion depth to 10.      the recursion depth to 10.
655    
656  26. Updated RunTest.bat in the distribution to the version supplied by Tom  27. Updated RunTest.bat in the distribution to the version supplied by Tom
657      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
658      argument validation and error reporting.      argument validation and error reporting.
659    
660  27. An instance of \X with an unlimited repeat could fail if at any point the  28. An instance of \X with an unlimited repeat could fail if at any point the
661      first character it looked at was a mark character.      first character it looked at was a mark character.
662    
663  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
664      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
665    
666  29. Added the '=' option to pcretest to check the setting of unused capturing  30. Added the '=' option to pcretest to check the setting of unused capturing
667      slots at the end of the pattern, which are documented as being -1, but are      slots at the end of the pattern, which are documented as being -1, but are
668      not included in the return count.      not included in the return count.
669    
670  30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE  31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
671      compiled something random. Now it gives a compile-time error (as does      compiled something random. Now it gives a compile-time error (as does
672      Perl).      Perl).
673    
674  31. A *MARK encountered during the processing of a positive assertion is now  32. A *MARK encountered during the processing of a positive assertion is now
675      recorded and passed back (compatible with Perl).      recorded and passed back (compatible with Perl).
676    
677  32. If --only-matching or --colour was set on a pcregrep call whose pattern  33. If --only-matching or --colour was set on a pcregrep call whose pattern
678      had alternative anchored branches, the search for a second match in a line      had alternative anchored branches, the search for a second match in a line
679      was done as if at the line start. Thus, for example, /^01|^02/ incorrectly      was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
680      matched the line "0102" twice. The same bug affected patterns that started      matched the line "0102" twice. The same bug affected patterns that started
681      with a backwards assertion. For example /\b01|\b02/ also matched "0102"      with a backwards assertion. For example /\b01|\b02/ also matched "0102"
682      twice.      twice.
683    
684  33. Previously, PCRE did not allow quantification of assertions. However, Perl  34. Previously, PCRE did not allow quantification of assertions. However, Perl
685      does, and because of capturing effects, quantifying parenthesized      does, and because of capturing effects, quantifying parenthesized
686      assertions may at times be useful. Quantifiers are now allowed for      assertions may at times be useful. Quantifiers are now allowed for
687      parenthesized assertions.      parenthesized assertions.
688    
689  34. A minor code tidy in pcre_compile() when checking options for \R usage.  35. A minor code tidy in pcre_compile() when checking options for \R usage.
690    
691    36. \g was being checked for fancy things in a character class, when it should
692        just be a literal "g".
693    
694    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
695        appearance of a nested POSIX class supersedes an apparent external class.
696        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
697        unescaped square brackets may also appear as part of class names. For
698        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
699        more like Perl. (But see 8.20/1 above.)
700    
701    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
702        was because it thought it was \N{name}, which is not supported).
703    
704    39. Add minix to OS list not supporting the -S option in pcretest.
705    
706    40. PCRE tries to detect cases of infinite recursion at compile time, but it
707        cannot analyze patterns in sufficient detail to catch mutual recursions
708        such as ((?1))((?2)). There is now a runtime test that gives an error if a
709        subgroup is called recursively as a subpattern for a second time at the
710        same position in the subject string. In previous releases this might have
711        been caught by the recursion limit, or it might have run out of stack.
712    
713    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
714        happen only once. PCRE was, however incorrectly giving a compile time error
715        "recursive call could loop indefinitely" because it cannot analyze the
716        pattern in sufficient detail. The compile time test no longer happens when
717        PCRE is compiling a conditional subpattern, but actual runaway loops are
718        now caught at runtime (see 40 above).
719    
720    42. It seems that Perl allows any characters other than a closing parenthesis
721        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
722        has been changed to be the same.
723    
724    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
725        as not to get warnings when autogen.sh is called. Also changed
726        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
727    
728    44. To help people who use pcregrep to scan files containing exceedingly long
729        lines, the following changes have been made:
730    
731        (a) The default value of the buffer size parameter has been increased from
732            8K to 20K. (The actual buffer used is three times this size.)
733    
734        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
735            PCRE is built.
736    
737        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
738            to be set at run time.
739    
740        (d) Numerical values in pcregrep options can be followed by K or M, for
741            example --buffer-size=50K.
742    
743        (e) If a line being scanned overflows pcregrep's buffer, an error is now
744            given and the return code is set to 2.
745    
746    45. Add a pointer to the latest mark to the callout data block.
747    
748    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
749        partial match of an empty string instead of no match. This was specific to
750        the use of ".".
751    
752    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
753        complete match instead of a partial match. This bug was dependent on both
754        the PCRE_UTF8 and PCRE_DOTALL options being set.
755    
756    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
757        starting byte set, because \b was not being ignored.
758    
759    
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