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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.10 03-Jun-2010  Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
60    
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
62    
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
65    
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
67    
68    17. The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    18. Added --file-list option to pcregrep.
71    
72    19. Added binary file support to pcregrep, including the -a, --binary-files,
73        -I, and --text options.
74    
75    20. The madvise function is renamed for posix_madvise for QNX compatibility
76        reasons. Fixed by Giuseppe D'Angelo.
77    
78    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
79    
80    22. Changed the option for creating symbolic links for 16-bit man pages from
81        -s to -sf so that re-installing does not cause issues.
82    
83    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
84    
85    
86    Version 8.30 04-February-2012
87    -----------------------------
88    
89    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
90        name is defined in ctype.h.
91    
92    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
93        only in quite long subpatterns.
94    
95    3.  Removed the function pcre_info(), which has been obsolete and deprecated
96        since it was replaced by pcre_fullinfo() in February 2000.
97    
98    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
99        match a (*MARK), and the match failed at the start of the subject, a
100        reference to memory before the start of the subject could occur. This bug
101        was introduced by fix 17 of release 8.21.
102    
103    5.  A reference to an unset group with zero minimum repetition was giving
104        totally wrong answers (in non-JavaScript-compatibility mode). For example,
105        /(another)?(\1?)test/ matched against "hello world test". This bug was
106        introduced in release 8.13.
107    
108    6.  Add support for 16-bit character strings (a large amount of work involving
109        many changes and refactorings).
110    
111    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
112        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
113        from a file.
114    
115    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
116        rounding is not applied in this particular case).
117    
118    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
119        if they appear, or are escaped, in patterns.
120    
121    10. Get rid of a number of -Wunused-but-set-variable warnings.
122    
123    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
124        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
125        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
126        also returns the mark "x". This bug applied to capturing parentheses,
127        non-capturing parentheses, and atomic parentheses. It also applied to some
128        assertions.
129    
130    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
131        information out of configure.ac instead of relying on pcre.h.generic, which
132        is not stored in the repository.
133    
134    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
135        -lreadline.
136    
137    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
138    
139    15. Applied Graycode's patch to put the top-level frame on the stack rather
140        than the heap when not using the stack for recursion. This gives a
141        performance improvement in many cases when recursion is not deep.
142    
143    16. Experimental code added to "pcretest -C" to output the stack frame size.
144    
145    
146    Version 8.21 12-Dec-2011
147    ------------------------
148    
149    1.  Updating the JIT compiler.
150    
151    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
152        are added as well.
153    
154    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
155        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
156        calling _pcre_jit_exec. Some extra comments are added.
157    
158    4.  (*MARK) settings inside atomic groups that do not contain any capturing
159        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
160        was introduced by change 18 for 8.20.
161    
162    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
163        ECMA-262 standard.
164    
165    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
166        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
167        This bug was probably introduced by change 9 of 8.13.
168    
169    7.  While fixing 6 above, I noticed that a number of other items were being
170        incorrectly rejected as "not fixed length". This arose partly because newer
171        opcodes had not been added to the fixed-length checking code. I have (a)
172        corrected the bug and added tests for these items, and (b) arranged for an
173        error to occur if an unknown opcode is encountered while checking for fixed
174        length instead of just assuming "not fixed length". The items that were
175        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
176        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
177        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
178    
179    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
180        being incorrectly compiled and would have given unpredicatble results.
181    
182    9.  A possessively repeated subpattern with minimum repeat count greater than
183        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
184        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
185        the first (A) could occur when it should not.
186    
187    10. Add a cast and remove a redundant test from the code.
188    
189    11. JIT should use pcre_malloc/pcre_free for allocation.
190    
191    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
192        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
193        is anything other than /usr, -L is still shown).
194    
195    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
196    
197    14. Perl does not support \N without a following name in a [] class; PCRE now
198        also gives an error.
199    
200    15. If a forward reference was repeated with an upper limit of around 2000,
201        it caused the error "internal error: overran compiling workspace". The
202        maximum number of forward references (including repeats) was limited by the
203        internal workspace, and dependent on the LINK_SIZE. The code has been
204        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
205        the default depends on LINK_SIZE. There is a new upper limit (for safety)
206        of around 200,000 forward references. While doing this, I also speeded up
207        the filling in of repeated forward references.
208    
209    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
210        incorrectly expecting the subject to contain another "a" after the start.
211    
212    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
213        in the match, the SKIP should be ignored. This was not happening; instead
214        the SKIP was being treated as NOMATCH. For patterns such as
215        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
216        tested.
217    
218    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
219        now much more compatible with Perl, in particular in cases where the result
220        is a non-match for a non-anchored pattern. For example, if
221        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
222        "m", where previously it did not return a name. A side effect of this
223        change is that for partial matches, the last encountered mark name is
224        returned, as for non matches. A number of tests that were previously not
225        Perl-compatible have been moved into the Perl-compatible test files. The
226        refactoring has had the pleasing side effect of removing one argument from
227        the match() function, thus reducing its stack requirements.
228    
229    19. If the /S+ option was used in pcretest to study a pattern using JIT,
230        subsequent uses of /S (without +) incorrectly behaved like /S+.
231    
232    21. Retrieve executable code size support for the JIT compiler and fixing
233        some warnings.
234    
235    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
236        not work when the shorter character appeared right at the end of the
237        subject string.
238    
239    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
240        systems.
241    
242    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
243        output it when the /M option is used in pcretest.
244    
245    25. The CheckMan script was not being included in the distribution. Also, added
246        an explicit "perl" to run Perl scripts from the PrepareRelease script
247        because this is reportedly needed in Windows.
248    
249    26. If study data was being save in a file and studying had not found a set of
250        "starts with" bytes for the pattern, the data written to the file (though
251        never used) was taken from uninitialized memory and so caused valgrind to
252        complain.
253    
254    27. Updated RunTest.bat as provided by Sheri Pierce.
255    
256    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
257    
258    29. Computation of memory usage for the table of capturing group names was
259        giving an unnecessarily large value.
260    
261    
262    Version 8.20 21-Oct-2011
263    ------------------------
264    
265    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
266        a POSIX class. After further experiments with Perl, which convinced me that
267        Perl has bugs and confusions, a closing square bracket is no longer allowed
268        in a POSIX name. This bug also affected patterns with classes that started
269        with full stops.
270    
271    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
272        captured substring, but while checking the failing first alternative,
273        substring 1 is temporarily captured. If the output vector supplied to
274        pcre_exec() was not big enough for this capture, the yield of the function
275        was still zero ("insufficient space for captured substrings"). This cannot
276        be totally fixed without adding another stack variable, which seems a lot
277        of expense for a edge case. However, I have improved the situation in cases
278        such as /(a)(b)x|abc/ matched against "abc", where the return code
279        indicates that fewer than the maximum number of slots in the ovector have
280        been set.
281    
282    3.  Related to (2) above: when there are more back references in a pattern than
283        slots in the output vector, pcre_exec() uses temporary memory during
284        matching, and copies in the captures as far as possible afterwards. It was
285        using the entire output vector, but this conflicts with the specification
286        that only 2/3 is used for passing back captured substrings. Now it uses
287        only the first 2/3, for compatibility. This is, of course, another edge
288        case.
289    
290    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
291        main code base, and can be used by building with --enable-jit. When this is
292        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
293        runtime --no-jit option is given.
294    
295    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
296        ovector, the return from the function was zero, implying that there were
297        other matches that did not fit. The correct "exactly full" value is now
298        returned.
299    
300    6.  If a subpattern that was called recursively or as a subroutine contained
301        (*PRUNE) or any other control that caused it to give a non-standard return,
302        invalid errors such as "Error -26 (nested recursion at the same subject
303        position)" or even infinite loops could occur.
304    
305    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
306        computing the minimum length on reaching *ACCEPT, and so ended up with the
307        wrong value of 1 rather than 0. Further investigation indicates that
308        computing a minimum subject length in the presence of *ACCEPT is difficult
309        (think back references, subroutine calls), and so I have changed the code
310        so that no minimum is registered for a pattern that contains *ACCEPT.
311    
312    8.  If (*THEN) was present in the first (true) branch of a conditional group,
313        it was not handled as intended. [But see 16 below.]
314    
315    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
316        Sheri Pierce.
317    
318    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
319        the first byte in a match must be "a".
320    
321    11. Change 17 for 8.13 increased the recursion depth for patterns like
322        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
323        pattern contains any instances of (*THEN). If it does not, the old
324        optimizations are restored. It would be nice to do this on a per-group
325        basis, but at the moment that is not feasible.
326    
327    12. In some environments, the output of pcretest -C is CRLF terminated. This
328        broke RunTest's code that checks for the link size. A single white space
329        character after the value is now allowed for.
330    
331    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
332        For "fr", it uses the Windows-specific input and output files.
333    
334    14. If (*THEN) appeared in a group that was called recursively or as a
335        subroutine, it did not work as intended. [But see next item.]
336    
337    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
338        pattern fragments (but not containing any | characters). If A and B are
339        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
340        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
341        D. In other words, Perl considers parentheses that do not contain any |
342        characters to be part of a surrounding alternative, whereas PCRE was
343        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
344        differently. PCRE now behaves in the same way as Perl, except in the case
345        of subroutine/recursion calls such as (?1) which have in any case always
346        been different (but PCRE had them first :-).
347    
348    16. Related to 15 above: Perl does not treat the | in a conditional group as
349        creating alternatives. Such a group is treated in the same way as an
350        ordinary group without any | characters when processing (*THEN). PCRE has
351        been changed to match Perl's behaviour.
352    
353    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
354        RunGrepTest script failed.
355    
356    18. Change 22 for version 13 caused atomic groups to use more stack. This is
357        inevitable for groups that contain captures, but it can lead to a lot of
358        stack use in large patterns. The old behaviour has been restored for atomic
359        groups that do not contain any capturing parentheses.
360    
361    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
362        suppress the check for a minimum subject length at run time. (If it was
363        given to pcre_exec() or pcre_dfa_exec() it did work.)
364    
365    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
366        fail to work when decoding hex characters in data strings in EBCDIC
367        environments.
368    
369    21. It appears that in at least one Mac OS environment, the isxdigit() function
370        is implemented as a macro that evaluates to its argument more than once,
371        contravening the C 90 Standard (I haven't checked a later standard). There
372        was an instance in pcretest which caused it to go wrong when processing
373        \x{...} escapes in subject strings. The has been rewritten to avoid using
374        things like p++ in the argument of isxdigit().
375    
376    
377    Version 8.13 16-Aug-2011
378    ------------------------
379    
380    1.  The Unicode data tables have been updated to Unicode 6.0.0.
381    
382    2.  Two minor typos in pcre_internal.h have been fixed.
383    
384    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
385        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
386        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
387    
388    4.  There were a number of related bugs in the code for matching backrefences
389        caselessly in UTF-8 mode when codes for the characters concerned were
390        different numbers of bytes. For example, U+023A and U+2C65 are an upper
391        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
392        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
393        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
394        2-byte code at the end of the subject (it thought there wasn't enough data
395        left).
396    
397    5.  Comprehensive information about what went wrong is now returned by
398        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
399        as the output vector has at least 2 elements. The offset of the start of
400        the failing character and a reason code are placed in the vector.
401    
402    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
403        now returned is for the first byte of the failing character, instead of the
404        last byte inspected. This is an incompatible change, but I hope it is small
405        enough not to be a problem. It makes the returned offset consistent with
406        pcre_exec() and pcre_dfa_exec().
407    
408    7.  pcretest now gives a text phrase as well as the error number when
409        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
410        failure, the offset and reason code are output.
411    
412    8.  When \R was used with a maximizing quantifier it failed to skip backwards
413        over a \r\n pair if the subsequent match failed. Instead, it just skipped
414        back over a single character (\n). This seems wrong (because it treated the
415        two characters as a single entity when going forwards), conflicts with the
416        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
417        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
418        has been changed.
419    
420    9.  Some internal refactoring has changed the processing so that the handling
421        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
422        time (the PCRE_DOTALL option was changed this way some time ago: version
423        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
424        which was always a bit of a fudge. It also means that there is one less
425        argument for the match() function, which reduces its stack requirements
426        slightly. This change also fixes an incompatibility with Perl: the pattern
427        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
428    
429    10. More internal refactoring has drastically reduced the number of recursive
430        calls to match() for possessively repeated groups such as (abc)++ when
431        using pcre_exec().
432    
433    11. While implementing 10, a number of bugs in the handling of groups were
434        discovered and fixed:
435    
436        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
437        (a|)*(?1) gave a compile-time internal error.
438        ((a|)+)+  did not notice that the outer group could match an empty string.
439        (^a|^)+   was not marked as anchored.
440        (.*a|.*)+ was not marked as matching at start or after a newline.
441    
442    12. Yet more internal refactoring has removed another argument from the match()
443        function. Special calls to this function are now indicated by setting a
444        value in a variable in the "match data" data block.
445    
446    13. Be more explicit in pcre_study() instead of relying on "default" for
447        opcodes that mean there is no starting character; this means that when new
448        ones are added and accidentally left out of pcre_study(), testing should
449        pick them up.
450    
451    14. The -s option of pcretest has been documented for ages as being an old
452        synonym of -m (show memory usage). I have changed it to mean "force study
453        for every regex", that is, assume /S for every regex. This is similar to -i
454        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
455        using it. It makes it easier to run collections of tests with and without
456        study enabled, and thereby test pcre_study() more easily. All the standard
457        tests are now run with and without -s (but some patterns can be marked as
458        "never study" - see 20 below).
459    
460    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
461        restoration of the capturing data to the outer values was not happening
462        correctly.
463    
464    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
465        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
466        pattern had matched an empty string, and so incorrectly returned a no
467        match.
468    
469    17. There was optimizing code for the last branch of non-capturing parentheses,
470        and also for the obeyed branch of a conditional subexpression, which used
471        tail recursion to cut down on stack usage. Unfortunately, now that there is
472        the possibility of (*THEN) occurring in these branches, tail recursion is
473        no longer possible because the return has to be checked for (*THEN). These
474        two optimizations have therefore been removed. [But see 8.20/11 above.]
475    
476    18. If a pattern containing \R was studied, it was assumed that \R always
477        matched two bytes, thus causing the minimum subject length to be
478        incorrectly computed because \R can also match just one byte.
479    
480    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
481        was incorrectly computed.
482    
483    20. If /S is present twice on a test pattern in pcretest input, it now
484        *disables* studying, thereby overriding the use of -s on the command line
485        (see 14 above). This is necessary for one or two tests to keep the output
486        identical in both cases.
487    
488    21. When (*ACCEPT) was used in an assertion that matched an empty string and
489        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
490    
491    22. When an atomic group that contained a capturing parenthesis was
492        successfully matched, but the branch in which it appeared failed, the
493        capturing was not being forgotten if a higher numbered group was later
494        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
495        group 1 to "a", when in fact it should be unset. This applied to multi-
496        branched capturing and non-capturing groups, repeated or not, and also to
497        positive assertions (capturing in negative assertions does not happen
498        in PCRE) and also to nested atomic groups.
499    
500    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
501        subject after a captured substring, to make it easier to tell which of a
502        number of identical substrings has been captured.
503    
504    24. The way atomic groups are processed by pcre_exec() has been changed so that
505        if they are repeated, backtracking one repetition now resets captured
506        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
507        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
508        "aaa". Previously, it would have been "a". As part of this code
509        refactoring, the way recursive calls are handled has also been changed.
510    
511    25. If an assertion condition captured any substrings, they were not passed
512        back unless some other capturing happened later. For example, if
513        (?(?=(a))a) was matched against "a", no capturing was returned.
514    
515    26. When studying a pattern that contained subroutine calls or assertions,
516        the code for finding the minimum length of a possible match was handling
517        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
518        group 1 called group 2 while simultaneously a separate group 2 called group
519        1). A stack overflow occurred in this case. I have fixed this by limiting
520        the recursion depth to 10.
521    
522    27. Updated RunTest.bat in the distribution to the version supplied by Tom
523        Fortmann. This supports explicit test numbers on the command line, and has
524        argument validation and error reporting.
525    
526    28. An instance of \X with an unlimited repeat could fail if at any point the
527        first character it looked at was a mark character.
528    
529    29. Some minor code refactoring concerning Unicode properties and scripts
530        should reduce the stack requirement of match() slightly.
531    
532    30. Added the '=' option to pcretest to check the setting of unused capturing
533        slots at the end of the pattern, which are documented as being -1, but are
534        not included in the return count.
535    
536    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
537        compiled something random. Now it gives a compile-time error (as does
538        Perl).
539    
540    32. A *MARK encountered during the processing of a positive assertion is now
541        recorded and passed back (compatible with Perl).
542    
543    33. If --only-matching or --colour was set on a pcregrep call whose pattern
544        had alternative anchored branches, the search for a second match in a line
545        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
546        matched the line "0102" twice. The same bug affected patterns that started
547        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
548        twice.
549    
550    34. Previously, PCRE did not allow quantification of assertions. However, Perl
551        does, and because of capturing effects, quantifying parenthesized
552        assertions may at times be useful. Quantifiers are now allowed for
553        parenthesized assertions.
554    
555    35. A minor code tidy in pcre_compile() when checking options for \R usage.
556    
557    36. \g was being checked for fancy things in a character class, when it should
558        just be a literal "g".
559    
560    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
561        appearance of a nested POSIX class supersedes an apparent external class.
562        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
563        unescaped square brackets may also appear as part of class names. For
564        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
565        more like Perl. (But see 8.20/1 above.)
566    
567    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
568        was because it thought it was \N{name}, which is not supported).
569    
570    39. Add minix to OS list not supporting the -S option in pcretest.
571    
572    40. PCRE tries to detect cases of infinite recursion at compile time, but it
573        cannot analyze patterns in sufficient detail to catch mutual recursions
574        such as ((?1))((?2)). There is now a runtime test that gives an error if a
575        subgroup is called recursively as a subpattern for a second time at the
576        same position in the subject string. In previous releases this might have
577        been caught by the recursion limit, or it might have run out of stack.
578    
579    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
580        happen only once. PCRE was, however incorrectly giving a compile time error
581        "recursive call could loop indefinitely" because it cannot analyze the
582        pattern in sufficient detail. The compile time test no longer happens when
583        PCRE is compiling a conditional subpattern, but actual runaway loops are
584        now caught at runtime (see 40 above).
585    
586    42. It seems that Perl allows any characters other than a closing parenthesis
587        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
588        has been changed to be the same.
589    
590    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
591        as not to get warnings when autogen.sh is called. Also changed
592        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
593    
594    44. To help people who use pcregrep to scan files containing exceedingly long
595        lines, the following changes have been made:
596    
597        (a) The default value of the buffer size parameter has been increased from
598            8K to 20K. (The actual buffer used is three times this size.)
599    
600        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
601            PCRE is built.
602    
603        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
604            to be set at run time.
605    
606        (d) Numerical values in pcregrep options can be followed by K or M, for
607            example --buffer-size=50K.
608    
609        (e) If a line being scanned overflows pcregrep's buffer, an error is now
610            given and the return code is set to 2.
611    
612    45. Add a pointer to the latest mark to the callout data block.
613    
614    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
615        partial match of an empty string instead of no match. This was specific to
616        the use of ".".
617    
618    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
619        complete match instead of a partial match. This bug was dependent on both
620        the PCRE_UTF8 and PCRE_DOTALL options being set.
621    
622    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
623        starting byte set, because \b was not being ignored.
624    
625    
626    Version 8.12 15-Jan-2011
627    ------------------------
628    
629    1.  Fixed some typos in the markup of the man pages, and wrote a script that
630        checks for such things as part of the documentation building process.
631    
632    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
633        --match-limit and --recursion-limit options (added for 8.11). In
634        particular, this made one of the standard tests fail. (The integer value
635        went into the wrong half of a long int.)
636    
637    3.  If the --colour option was given to pcregrep with -v (invert match), it
638        did strange things, either producing crazy output, or crashing. It should,
639        of course, ignore a request for colour when reporting lines that do not
640        match.
641    
642    4.  Another pcregrep bug caused similar problems if --colour was specified with
643        -M (multiline) and the pattern match finished with a line ending.
644    
645    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
646        matched in multiline mode, the following line was shown as part of the
647        match. This seems wrong, so I have changed it.
648    
649    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
650        the check for further matches in the same line (so they could be coloured)
651        to overrun the end of the current line. If another match was found, it was
652        incorrectly shown (and then shown again when found in the next line).
653    
654    7.  If pcregrep was compiled under Windows, there was a reference to the
655        function pcregrep_exit() before it was defined. I am assuming this was
656        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
657        reported by a user. I've moved the definition above the reference.
658    
659    
660    Version 8.11 10-Dec-2010
661    ------------------------
662    
663    1.  (*THEN) was not working properly if there were untried alternatives prior
664        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
665        backtracked to try for "b" instead of moving to the next alternative branch
666        at the same level (in this case, to look for "c"). The Perl documentation
667        is clear that when (*THEN) is backtracked onto, it goes to the "next
668        alternative in the innermost enclosing group".
669    
670    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
671        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
672        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
673        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
674        (*THEN).
675    
676    3.  If \s appeared in a character class, it removed the VT character from
677        the class, even if it had been included by some previous item, for example
678        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
679        of \s, but is part of the POSIX "space" class.)
680    
681    4.  A partial match never returns an empty string (because you can always
682        match an empty string at the end of the subject); however the checking for
683        an empty string was starting at the "start of match" point. This has been
684        changed to the "earliest inspected character" point, because the returned
685        data for a partial match starts at this character. This means that, for
686        example, /(?<=abc)def/ gives a partial match for the subject "abc"
687        (previously it gave "no match").
688    
689    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
690        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
691        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
692        has an implication that the given string is incomplete (because a partial
693        match is preferred over a full match). For this reason, these items now
694        give a partial match in this situation. [Aside: previously, the one case
695        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
696        match rather than a full match, which was wrong by the old rules, but is
697        now correct.]
698    
699    6.  There was a bug in the handling of #-introduced comments, recognized when
700        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
701        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
702        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
703        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
704        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
705        places in pcre_compile().
706    
707    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
708        comments when looking ahead for named forward references to subpatterns,
709        the only newline sequence it recognized was NL. It now handles newlines
710        according to the set newline convention.
711    
712    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
713        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
714        cater for a lack of strerror(). These oversights have been fixed.
715    
716    9.  Added --match-limit and --recursion-limit to pcregrep.
717    
718    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
719    
720    11. When the -o option was used, pcregrep was setting a return code of 1, even
721        when matches were found, and --line-buffered was not being honoured.
722    
723    12. Added an optional parentheses number to the -o and --only-matching options
724        of pcregrep.
725    
726    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
727        can match an empty string. The code to do it in pcretest and pcredemo
728        needed fixing:
729    
730        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
731            only one byte after an empty string match just before CRLF (this case
732            just got forgotten; "any" and "anycrlf" were OK).
733    
734        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
735            mode when an empty string match preceded an ASCII character followed by
736            a non-ASCII character. (The code for advancing by one character rather
737            than one byte was nonsense.)
738    
739        (c) The pcredemo.c sample program did not have any code at all to handle
740            the cases when CRLF is a valid newline sequence.
741    
742    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
743        as a starting offset was within the subject string. There is now a new
744        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
745        negative or greater than the length of the string. In order to test this,
746        pcretest is extended to allow the setting of negative starting offsets.
747    
748    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
749        starting offset points to the beginning of a UTF-8 character was
750        unnecessarily clumsy. I tidied it up.
751    
752    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
753        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
754    
755    17. Nobody had reported that the --include_dir option, which was added in
756        release 7.7 should have been called --include-dir (hyphen, not underscore)
757        for compatibility with GNU grep. I have changed it to --include-dir, but
758        left --include_dir as an undocumented synonym, and the same for
759        --exclude-dir, though that is not available in GNU grep, at least as of
760        release 2.5.4.
761    
762    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
763        characters from a string of bytes) have been redefined so as not to use
764        loops, in order to improve performance in some environments. At the same
765        time, I abstracted some of the common code into auxiliary macros to save
766        repetition (this should not affect the compiled code).
767    
768    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
769        compile-time error is now given if \c is not followed by an ASCII
770        character, that is, a byte less than 128. (In EBCDIC mode, the code is
771        different, and any byte value is allowed.)
772    
773    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
774        START_OPTIMIZE option, which is now allowed at compile time - but just
775        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
776        to pcregrep and other applications that have no direct access to PCRE
777        options. The new /Y option in pcretest sets this option when calling
778        pcre_compile().
779    
780    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
781        back references. Groups containing recursive back references were forced to
782        be atomic by that change, but in the case of named groups, the amount of
783        memory required was incorrectly computed, leading to "Failed: internal
784        error: code overflow". This has been fixed.
785    
786    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
787        pcretest.c, to avoid build problems in some Borland environments.
788    
789    
790    Version 8.10 25-Jun-2010
791  ------------------------  ------------------------
792    
793  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 42  Version 8.10 03-Jun-2010 Line 828  Version 8.10 03-Jun-2010
828  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
829      studied, and the match started with a letter with a code point greater than      studied, and the match started with a letter with a code point greater than
830      127 whose first byte was different to the first byte of the other case of      127 whose first byte was different to the first byte of the other case of
831      the letter, the other case of this starting letter was not recognized      the letter, the other case of this starting letter was not recognized
832      (#976).      (#976).
833    
834  12. If a pattern that was studied started with a repeated Unicode property  12. If a pattern that was studied started with a repeated Unicode property
# Line 68  Version 8.10 03-Jun-2010 Line 854  Version 8.10 03-Jun-2010
854    
855  17. Added a check for running out of memory when PCRE is compiled with  17. Added a check for running out of memory when PCRE is compiled with
856      --disable-stack-for-recursion (#990).      --disable-stack-for-recursion (#990).
857    
858    18. If the last data line in a file for pcretest does not have a newline on
859        the end, a newline was missing in the output.
860    
861    19. The default pcre_chartables.c file recognizes only ASCII characters (values
862        less than 128) in its various bitmaps. However, there is a facility for
863        generating tables according to the current locale when PCRE is compiled. It
864        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
865        characters, are recognized by isspace() and therefore were getting set in
866        these tables, and indeed these tables seem to approximate to ISO 8859. This
867        caused a problem in UTF-8 mode when pcre_study() was used to create a list
868        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
869        which of course cannot start UTF-8 characters. I have changed the code so
870        that only real ASCII characters (less than 128) and the correct starting
871        bytes for UTF-8 encodings are set for characters greater than 127 when in
872        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
873        altogether.)
874    
875    20. Added the /T option to pcretest so as to be able to run tests with non-
876        standard character tables, thus making it possible to include the tests
877        used for 19 above in the standard set of tests.
878    
879    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
880        reference to a subpattern the other side of a comment that contains an
881        opening parenthesis caused either an internal compiling error, or a
882        reference to the wrong subpattern.
883    
884    
885  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010

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