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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    
18    Version 8.31 06-July-2012
19    -------------------------
20    
21    1.  Fixing a wrong JIT test case and some compiler warnings.
22    
23    2.  Removed a bashism from the RunTest script.
24    
25    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
26        to unsigned type, result still unsigned" that was given by an MS compiler
27        on encountering the code "-sizeof(xxx)".
28    
29    4.  Partial matching support is added to the JIT compiler.
30    
31    5.  Fixed several bugs concerned with partial matching of items that consist
32        of more than one character:
33    
34        (a) /^(..)\1/ did not partially match "aba" because checking references was
35            done on an "all or nothing" basis. This also applied to repeated
36            references.
37    
38        (b) \R did not give a hard partial match if \r was found at the end of the
39            subject.
40    
41        (c) \X did not give a hard partial match after matching one or more
42            characters at the end of the subject.
43    
44        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
45            a partial match for the string "\r".
46    
47        (e) When newline was set to CRLF, the metacharacter "." did not recognize
48            a partial match for a CR character at the end of the subject string.
49    
50    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
51        running pcretest, the text "(JIT)" added to the output whenever JIT is
52        actually used to run the match.
53    
54    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
55        or /S+[+] with a digit between 1 and 7.
56    
57    8.  OP_NOT now supports any UTF character not just single-byte ones.
58    
59    9.  (*MARK) control verb is now supported by the JIT compiler.
60    
61    10. The command "./RunTest list" lists the available tests without actually
62        running any of them. (Because I keep forgetting what they all are.)
63    
64    11. Add PCRE_INFO_MAXLOOKBEHIND.
65    
66    12. Applied a (slightly modified) user-supplied patch that improves performance
67        when the heap is used for recursion (compiled with --disable-stack-for-
68        recursion). Instead of malloc and free for each heap frame each time a
69        logical recursion happens, frames are retained on a chain and re-used where
70        possible. This sometimes gives as much as 30% improvement.
71    
72    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
73        call.
74    
75    14. As documented, (*COMMIT) is now confined to within a positive assertion.
76    
77    15. It is now possible to link pcretest with libedit as an alternative to
78        libreadline.
79    
80    16. (*COMMIT) control verb is now supported by the JIT compiler.
81    
82    17. The Unicode data tables have been updated to Unicode 6.1.0.
83    
84    18. Added --file-list option to pcregrep.
85    
86    19. Added binary file support to pcregrep, including the -a, --binary-files,
87        -I, and --text options.
88    
89    20. The madvise function is renamed for posix_madvise for QNX compatibility
90        reasons. Fixed by Giuseppe D'Angelo.
91    
92    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
93    
94    22. Changed the option for creating symbolic links for 16-bit man pages from
95        -s to -sf so that re-installing does not cause issues.
96    
97    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
98    
99    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
100        matches in certain environments (the workspace was not being correctly
101        retained). Also added to pcre_dfa_exec() a simple plausibility check on
102        some of the workspace data at the beginning of a restart.
103    
104    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
105        was not doing so when it should - probably a typo introduced by SVN 528
106        (change 8.10/14).
107    
108    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
109        \w+ when the character tables indicated that \x{c4} was a word character.
110        There were several related cases, all because the tests for doing a table
111        lookup were testing for characters less than 127 instead of 255.
112    
113    27. If a pattern contains capturing parentheses that are not used in a match,
114        their slots in the ovector are set to -1. For those that are higher than
115        any matched groups, this happens at the end of processing. In the case when
116        there were back references that the ovector was too small to contain
117        (causing temporary malloc'd memory to be used during matching), and the
118        highest capturing number was not used, memory off the end of the ovector
119        was incorrectly being set to -1. (It was using the size of the temporary
120        memory instead of the true size.)
121    
122    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
123        ovector size, it uses memory at the end of the block that it has got.
124    
125    29. Check for an overlong MARK name and give an error at compile time. The
126        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
127    
128    30. JIT compiler update.
129    
130    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
131        Rill for the patch.
132    
133    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
134    
135    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
136    
137    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
138        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
139        was enabled.
140    
141    35. Improve JIT code generation for greedy plus quantifier.
142    
143    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
144        1 to "aa" instead of to an empty string. The bug affected repeated groups
145        that could potentially match an empty string.
146    
147    37. Optimizing single character iterators in JIT.
148    
149    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
150        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
151        codepoints that are too big for the mode are faulted, and in a UTF mode,
152        disallowed codepoints are also faulted.
153    
154    39. If PCRE was compiled with UTF support, in three places in the DFA
155        matcher there was code that should only have been obeyed in UTF mode, but
156        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
157        processing when bytes with values greater than 127 were present. In 16-bit
158        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
159        both cases the values are those that cannot be the first data item in a UTF
160        character. The three items that might have provoked this were recursions,
161        possessively repeated groups, and atomic groups.
162    
163    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
164        and pcregrep, because some OS require shared objects to be explicitly
165        passed to ld, causing the link step to fail if they are not.
166    
167    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
168        mode, patterns that started with \h* or \R* might be incorrectly matched.
169    
170    
171    Version 8.30 04-February-2012
172    -----------------------------
173    
174    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
175        name is defined in ctype.h.
176    
177    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
178        only in quite long subpatterns.
179    
180    3.  Removed the function pcre_info(), which has been obsolete and deprecated
181        since it was replaced by pcre_fullinfo() in February 2000.
182    
183    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
184        match a (*MARK), and the match failed at the start of the subject, a
185        reference to memory before the start of the subject could occur. This bug
186        was introduced by fix 17 of release 8.21.
187    
188    5.  A reference to an unset group with zero minimum repetition was giving
189        totally wrong answers (in non-JavaScript-compatibility mode). For example,
190        /(another)?(\1?)test/ matched against "hello world test". This bug was
191        introduced in release 8.13.
192    
193    6.  Add support for 16-bit character strings (a large amount of work involving
194        many changes and refactorings).
195    
196    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
197        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
198        from a file.
199    
200    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
201        rounding is not applied in this particular case).
202    
203    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
204        if they appear, or are escaped, in patterns.
205    
206    10. Get rid of a number of -Wunused-but-set-variable warnings.
207    
208    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
209        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
210        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
211        also returns the mark "x". This bug applied to capturing parentheses,
212        non-capturing parentheses, and atomic parentheses. It also applied to some
213        assertions.
214    
215    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
216        information out of configure.ac instead of relying on pcre.h.generic, which
217        is not stored in the repository.
218    
219    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
220        -lreadline.
221    
222    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
223    
224    15. Applied Graycode's patch to put the top-level frame on the stack rather
225        than the heap when not using the stack for recursion. This gives a
226        performance improvement in many cases when recursion is not deep.
227    
228    16. Experimental code added to "pcretest -C" to output the stack frame size.
229    
230    
231    Version 8.21 12-Dec-2011
232    ------------------------
233    
234    1.  Updating the JIT compiler.
235    
236    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
237        are added as well.
238    
239    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
240        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
241        calling _pcre_jit_exec. Some extra comments are added.
242    
243    4.  (*MARK) settings inside atomic groups that do not contain any capturing
244        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
245        was introduced by change 18 for 8.20.
246    
247    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
248        ECMA-262 standard.
249    
250    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
251        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
252        This bug was probably introduced by change 9 of 8.13.
253    
254    7.  While fixing 6 above, I noticed that a number of other items were being
255        incorrectly rejected as "not fixed length". This arose partly because newer
256        opcodes had not been added to the fixed-length checking code. I have (a)
257        corrected the bug and added tests for these items, and (b) arranged for an
258        error to occur if an unknown opcode is encountered while checking for fixed
259        length instead of just assuming "not fixed length". The items that were
260        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
261        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
262        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
263    
264    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
265        being incorrectly compiled and would have given unpredicatble results.
266    
267    9.  A possessively repeated subpattern with minimum repeat count greater than
268        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
269        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
270        the first (A) could occur when it should not.
271    
272    10. Add a cast and remove a redundant test from the code.
273    
274    11. JIT should use pcre_malloc/pcre_free for allocation.
275    
276    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
277        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
278        is anything other than /usr, -L is still shown).
279    
280    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
281    
282    14. Perl does not support \N without a following name in a [] class; PCRE now
283        also gives an error.
284    
285    15. If a forward reference was repeated with an upper limit of around 2000,
286        it caused the error "internal error: overran compiling workspace". The
287        maximum number of forward references (including repeats) was limited by the
288        internal workspace, and dependent on the LINK_SIZE. The code has been
289        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
290        the default depends on LINK_SIZE. There is a new upper limit (for safety)
291        of around 200,000 forward references. While doing this, I also speeded up
292        the filling in of repeated forward references.
293    
294    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
295        incorrectly expecting the subject to contain another "a" after the start.
296    
297    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
298        in the match, the SKIP should be ignored. This was not happening; instead
299        the SKIP was being treated as NOMATCH. For patterns such as
300        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
301        tested.
302    
303    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
304        now much more compatible with Perl, in particular in cases where the result
305        is a non-match for a non-anchored pattern. For example, if
306        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
307        "m", where previously it did not return a name. A side effect of this
308        change is that for partial matches, the last encountered mark name is
309        returned, as for non matches. A number of tests that were previously not
310        Perl-compatible have been moved into the Perl-compatible test files. The
311        refactoring has had the pleasing side effect of removing one argument from
312        the match() function, thus reducing its stack requirements.
313    
314    19. If the /S+ option was used in pcretest to study a pattern using JIT,
315        subsequent uses of /S (without +) incorrectly behaved like /S+.
316    
317    21. Retrieve executable code size support for the JIT compiler and fixing
318        some warnings.
319    
320    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
321        not work when the shorter character appeared right at the end of the
322        subject string.
323    
324    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
325        systems.
326    
327    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
328        output it when the /M option is used in pcretest.
329    
330    25. The CheckMan script was not being included in the distribution. Also, added
331        an explicit "perl" to run Perl scripts from the PrepareRelease script
332        because this is reportedly needed in Windows.
333    
334    26. If study data was being save in a file and studying had not found a set of
335        "starts with" bytes for the pattern, the data written to the file (though
336        never used) was taken from uninitialized memory and so caused valgrind to
337        complain.
338    
339    27. Updated RunTest.bat as provided by Sheri Pierce.
340    
341    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
342    
343    29. Computation of memory usage for the table of capturing group names was
344        giving an unnecessarily large value.
345    
346    
347    Version 8.20 21-Oct-2011
348    ------------------------
349    
350    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
351        a POSIX class. After further experiments with Perl, which convinced me that
352        Perl has bugs and confusions, a closing square bracket is no longer allowed
353        in a POSIX name. This bug also affected patterns with classes that started
354        with full stops.
355    
356    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
357        captured substring, but while checking the failing first alternative,
358        substring 1 is temporarily captured. If the output vector supplied to
359        pcre_exec() was not big enough for this capture, the yield of the function
360        was still zero ("insufficient space for captured substrings"). This cannot
361        be totally fixed without adding another stack variable, which seems a lot
362        of expense for a edge case. However, I have improved the situation in cases
363        such as /(a)(b)x|abc/ matched against "abc", where the return code
364        indicates that fewer than the maximum number of slots in the ovector have
365        been set.
366    
367    3.  Related to (2) above: when there are more back references in a pattern than
368        slots in the output vector, pcre_exec() uses temporary memory during
369        matching, and copies in the captures as far as possible afterwards. It was
370        using the entire output vector, but this conflicts with the specification
371        that only 2/3 is used for passing back captured substrings. Now it uses
372        only the first 2/3, for compatibility. This is, of course, another edge
373        case.
374    
375    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
376        main code base, and can be used by building with --enable-jit. When this is
377        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
378        runtime --no-jit option is given.
379    
380    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
381        ovector, the return from the function was zero, implying that there were
382        other matches that did not fit. The correct "exactly full" value is now
383        returned.
384    
385    6.  If a subpattern that was called recursively or as a subroutine contained
386        (*PRUNE) or any other control that caused it to give a non-standard return,
387        invalid errors such as "Error -26 (nested recursion at the same subject
388        position)" or even infinite loops could occur.
389    
390    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
391        computing the minimum length on reaching *ACCEPT, and so ended up with the
392        wrong value of 1 rather than 0. Further investigation indicates that
393        computing a minimum subject length in the presence of *ACCEPT is difficult
394        (think back references, subroutine calls), and so I have changed the code
395        so that no minimum is registered for a pattern that contains *ACCEPT.
396    
397    8.  If (*THEN) was present in the first (true) branch of a conditional group,
398        it was not handled as intended. [But see 16 below.]
399    
400    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
401        Sheri Pierce.
402    
403    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
404        the first byte in a match must be "a".
405    
406    11. Change 17 for 8.13 increased the recursion depth for patterns like
407        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
408        pattern contains any instances of (*THEN). If it does not, the old
409        optimizations are restored. It would be nice to do this on a per-group
410        basis, but at the moment that is not feasible.
411    
412    12. In some environments, the output of pcretest -C is CRLF terminated. This
413        broke RunTest's code that checks for the link size. A single white space
414        character after the value is now allowed for.
415    
416    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
417        For "fr", it uses the Windows-specific input and output files.
418    
419    14. If (*THEN) appeared in a group that was called recursively or as a
420        subroutine, it did not work as intended. [But see next item.]
421    
422    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
423        pattern fragments (but not containing any | characters). If A and B are
424        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
425        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
426        D. In other words, Perl considers parentheses that do not contain any |
427        characters to be part of a surrounding alternative, whereas PCRE was
428        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
429        differently. PCRE now behaves in the same way as Perl, except in the case
430        of subroutine/recursion calls such as (?1) which have in any case always
431        been different (but PCRE had them first :-).
432    
433    16. Related to 15 above: Perl does not treat the | in a conditional group as
434        creating alternatives. Such a group is treated in the same way as an
435        ordinary group without any | characters when processing (*THEN). PCRE has
436        been changed to match Perl's behaviour.
437    
438    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
439        RunGrepTest script failed.
440    
441    18. Change 22 for version 13 caused atomic groups to use more stack. This is
442        inevitable for groups that contain captures, but it can lead to a lot of
443        stack use in large patterns. The old behaviour has been restored for atomic
444        groups that do not contain any capturing parentheses.
445    
446    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
447        suppress the check for a minimum subject length at run time. (If it was
448        given to pcre_exec() or pcre_dfa_exec() it did work.)
449    
450    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
451        fail to work when decoding hex characters in data strings in EBCDIC
452        environments.
453    
454    21. It appears that in at least one Mac OS environment, the isxdigit() function
455        is implemented as a macro that evaluates to its argument more than once,
456        contravening the C 90 Standard (I haven't checked a later standard). There
457        was an instance in pcretest which caused it to go wrong when processing
458        \x{...} escapes in subject strings. The has been rewritten to avoid using
459        things like p++ in the argument of isxdigit().
460    
461    
462    Version 8.13 16-Aug-2011
463  ------------------------  ------------------------
464    
465  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 478  Version 8.13 30-Apr-2011
478      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
479      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
480      left).      left).
481    
482  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
483      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
484      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
485      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
486    
487  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
488      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
489      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
490      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
491      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
492    
493  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
494      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
495      failure, the offset and reason code are output.      failure, the offset and reason code are output.
496    
497  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
498      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
499      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
500      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
501      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
502      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
503      has been changed.      has been changed.
504    
505  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
506      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
507      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
508      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,
509      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
510      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
511      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
512      (?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.
513    
514  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
515      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
516      using pcre_exec().      using pcre_exec().
517    
518  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
519      discovered and fixed:      discovered and fixed:
520    
521      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
522      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
523      ((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.
524      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
525      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
526    
527  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
528      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
529      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
530    
531  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
532      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
533      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
534      pick them up.      pick them up.
535    
536  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
537      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
538      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
539      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
540      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
541      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
542      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
543      "never study" - see 20 below).      "never study" - see 20 below).
544    
545  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
546      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
547      correctly.      correctly.
548    
549  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
550      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
551      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
552      match.      match.
553    
554  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,
555      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
556      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
557      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
558      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
559      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
560    
561  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
562      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
563      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
564    
565  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
566      was incorrectly computed.      was incorrectly computed.
567    
568  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
569      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
570      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
571        identical in both cases.
572    
573  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
574      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.
575    
576  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
577      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
578      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
579      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
580      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-
581      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
582      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
583      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
584    
585  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
586      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
587      number of identical substrings has been captured).      number of identical substrings has been captured.
588    
589  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
590      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
591      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
592      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
593      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
594      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
595    
596  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
597      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
598      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
599    
600  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
601      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
602      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
603      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
604      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
605      the recursion depth to 10.      the recursion depth to 10.
606    
607  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
608      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
609      argument validation and error reporting.      argument validation and error reporting.
610    
611  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
612      first character it looked at was a mark character.      first character it looked at was a mark character.
613    
614  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
615      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
616    
617  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
618      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
619      not included in the return count.      not included in the return count.
620    
621  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
622      compiled something random. Now it gives a compile-time error (as does      compiled something random. Now it gives a compile-time error (as does
623      Perl).      Perl).
624    
625  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
626      recorded and passed back (compatible with Perl).      recorded and passed back (compatible with Perl).
627    
628  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
629      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
630      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
631      matched the line "0102" twice. The same bug affected patterns that started      matched the line "0102" twice. The same bug affected patterns that started
632      with a backwards assertion. For example /\b01|\b02/ also matched "0102"      with a backwards assertion. For example /\b01|\b02/ also matched "0102"
633      twice.      twice.
634    
635  33. Previously, PCRE did not allow quantification of assertions. However, Perl  34. Previously, PCRE did not allow quantification of assertions. However, Perl
636      does, and because of capturing effects, quantifying parenthesized      does, and because of capturing effects, quantifying parenthesized
637      assertions may at times be useful. Quantifiers are now allowed for      assertions may at times be useful. Quantifiers are now allowed for
638      parenthesized assertions.      parenthesized assertions.
639    
640    35. A minor code tidy in pcre_compile() when checking options for \R usage.
641    
642    36. \g was being checked for fancy things in a character class, when it should
643        just be a literal "g".
644    
645    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
646        appearance of a nested POSIX class supersedes an apparent external class.
647        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
648        unescaped square brackets may also appear as part of class names. For
649        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
650        more like Perl. (But see 8.20/1 above.)
651    
652    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
653        was because it thought it was \N{name}, which is not supported).
654    
655    39. Add minix to OS list not supporting the -S option in pcretest.
656    
657    40. PCRE tries to detect cases of infinite recursion at compile time, but it
658        cannot analyze patterns in sufficient detail to catch mutual recursions
659        such as ((?1))((?2)). There is now a runtime test that gives an error if a
660        subgroup is called recursively as a subpattern for a second time at the
661        same position in the subject string. In previous releases this might have
662        been caught by the recursion limit, or it might have run out of stack.
663    
664    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
665        happen only once. PCRE was, however incorrectly giving a compile time error
666        "recursive call could loop indefinitely" because it cannot analyze the
667        pattern in sufficient detail. The compile time test no longer happens when
668        PCRE is compiling a conditional subpattern, but actual runaway loops are
669        now caught at runtime (see 40 above).
670    
671    42. It seems that Perl allows any characters other than a closing parenthesis
672        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
673        has been changed to be the same.
674    
675    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
676        as not to get warnings when autogen.sh is called. Also changed
677        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
678    
679    44. To help people who use pcregrep to scan files containing exceedingly long
680        lines, the following changes have been made:
681    
682        (a) The default value of the buffer size parameter has been increased from
683            8K to 20K. (The actual buffer used is three times this size.)
684    
685        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
686            PCRE is built.
687    
688        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
689            to be set at run time.
690    
691        (d) Numerical values in pcregrep options can be followed by K or M, for
692            example --buffer-size=50K.
693    
694        (e) If a line being scanned overflows pcregrep's buffer, an error is now
695            given and the return code is set to 2.
696    
697    45. Add a pointer to the latest mark to the callout data block.
698    
699    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
700        partial match of an empty string instead of no match. This was specific to
701        the use of ".".
702    
703    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
704        complete match instead of a partial match. This bug was dependent on both
705        the PCRE_UTF8 and PCRE_DOTALL options being set.
706    
707    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
708        starting byte set, because \b was not being ignored.
709    
710    
711  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
712  ------------------------  ------------------------

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