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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  Version 8.31
5    -----------------------------
7    1.  Fixing a wrong JIT test case and some compiler warnings.
9    2.  Removed a bashism from the RunTest script.
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)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
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.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
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.
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.
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
45    9.  (*MARK) control verb is now supported by the JIT compiler.
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.)
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.
59    Version 8.30 04-February-2012
60    -----------------------------
62    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
63        name is defined in ctype.h.
65    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
66        only in quite long subpatterns.
68    3.  Removed the function pcre_info(), which has been obsolete and deprecated
69        since it was replaced by pcre_fullinfo() in February 2000.
71    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
72        match a (*MARK), and the match failed at the start of the subject, a
73        reference to memory before the start of the subject could occur. This bug
74        was introduced by fix 17 of release 8.21.
76    5.  A reference to an unset group with zero minimum repetition was giving
77        totally wrong answers (in non-JavaScript-compatibility mode). For example,
78        /(another)?(\1?)test/ matched against "hello world test". This bug was
79        introduced in release 8.13.
81    6.  Add support for 16-bit character strings (a large amount of work involving
82        many changes and refactorings).
84    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
85        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
86        from a file.
88    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
89        rounding is not applied in this particular case).
91    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
92        if they appear, or are escaped, in patterns.
94    10. Get rid of a number of -Wunused-but-set-variable warnings.
96    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
97        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
98        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
99        also returns the mark "x". This bug applied to capturing parentheses,
100        non-capturing parentheses, and atomic parentheses. It also applied to some
101        assertions.
103    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
104        information out of configure.ac instead of relying on pcre.h.generic, which
105        is not stored in the repository.
107    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
108        -lreadline.
110    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
112    15. Applied Graycode's patch to put the top-level frame on the stack rather
113        than the heap when not using the stack for recursion. This gives a
114        performance improvement in many cases when recursion is not deep.
116    16. Experimental code added to "pcretest -C" to output the stack frame size.
119    Version 8.21 12-Dec-2011
120    ------------------------
122    1.  Updating the JIT compiler.
124    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
125        are added as well.
127    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
128        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
129        calling _pcre_jit_exec. Some extra comments are added.
131    4.  (*MARK) settings inside atomic groups that do not contain any capturing
132        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
133        was introduced by change 18 for 8.20.
135    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
136        ECMA-262 standard.
138    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
139        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
140        This bug was probably introduced by change 9 of 8.13.
142    7.  While fixing 6 above, I noticed that a number of other items were being
143        incorrectly rejected as "not fixed length". This arose partly because newer
144        opcodes had not been added to the fixed-length checking code. I have (a)
145        corrected the bug and added tests for these items, and (b) arranged for an
146        error to occur if an unknown opcode is encountered while checking for fixed
147        length instead of just assuming "not fixed length". The items that were
148        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
149        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
150        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
152    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
153        being incorrectly compiled and would have given unpredicatble results.
155    9.  A possessively repeated subpattern with minimum repeat count greater than
156        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
157        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
158        the first (A) could occur when it should not.
160    10. Add a cast and remove a redundant test from the code.
162    11. JIT should use pcre_malloc/pcre_free for allocation.
164    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
165        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
166        is anything other than /usr, -L is still shown).
168    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
170    14. Perl does not support \N without a following name in a [] class; PCRE now
171        also gives an error.
173    15. If a forward reference was repeated with an upper limit of around 2000,
174        it caused the error "internal error: overran compiling workspace". The
175        maximum number of forward references (including repeats) was limited by the
176        internal workspace, and dependent on the LINK_SIZE. The code has been
177        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
178        the default depends on LINK_SIZE. There is a new upper limit (for safety)
179        of around 200,000 forward references. While doing this, I also speeded up
180        the filling in of repeated forward references.
182    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
183        incorrectly expecting the subject to contain another "a" after the start.
185    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
186        in the match, the SKIP should be ignored. This was not happening; instead
187        the SKIP was being treated as NOMATCH. For patterns such as
188        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
189        tested.
191    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
192        now much more compatible with Perl, in particular in cases where the result
193        is a non-match for a non-anchored pattern. For example, if
194        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
195        "m", where previously it did not return a name. A side effect of this
196        change is that for partial matches, the last encountered mark name is
197        returned, as for non matches. A number of tests that were previously not
198        Perl-compatible have been moved into the Perl-compatible test files. The
199        refactoring has had the pleasing side effect of removing one argument from
200        the match() function, thus reducing its stack requirements.
202    19. If the /S+ option was used in pcretest to study a pattern using JIT,
203        subsequent uses of /S (without +) incorrectly behaved like /S+.
205    21. Retrieve executable code size support for the JIT compiler and fixing
206        some warnings.
208    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
209        not work when the shorter character appeared right at the end of the
210        subject string.
212    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
213        systems.
215    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
216        output it when the /M option is used in pcretest.
218    25. The CheckMan script was not being included in the distribution. Also, added
219        an explicit "perl" to run Perl scripts from the PrepareRelease script
220        because this is reportedly needed in Windows.
222    26. If study data was being save in a file and studying had not found a set of
223        "starts with" bytes for the pattern, the data written to the file (though
224        never used) was taken from uninitialized memory and so caused valgrind to
225        complain.
227    27. Updated RunTest.bat as provided by Sheri Pierce.
229    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
231    29. Computation of memory usage for the table of capturing group names was
232        giving an unnecessarily large value.
235    Version 8.20 21-Oct-2011
236    ------------------------
238    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
239        a POSIX class. After further experiments with Perl, which convinced me that
240        Perl has bugs and confusions, a closing square bracket is no longer allowed
241        in a POSIX name. This bug also affected patterns with classes that started
242        with full stops.
244    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
245        captured substring, but while checking the failing first alternative,
246        substring 1 is temporarily captured. If the output vector supplied to
247        pcre_exec() was not big enough for this capture, the yield of the function
248        was still zero ("insufficient space for captured substrings"). This cannot
249        be totally fixed without adding another stack variable, which seems a lot
250        of expense for a edge case. However, I have improved the situation in cases
251        such as /(a)(b)x|abc/ matched against "abc", where the return code
252        indicates that fewer than the maximum number of slots in the ovector have
253        been set.
255    3.  Related to (2) above: when there are more back references in a pattern than
256        slots in the output vector, pcre_exec() uses temporary memory during
257        matching, and copies in the captures as far as possible afterwards. It was
258        using the entire output vector, but this conflicts with the specification
259        that only 2/3 is used for passing back captured substrings. Now it uses
260        only the first 2/3, for compatibility. This is, of course, another edge
261        case.
263    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
264        main code base, and can be used by building with --enable-jit. When this is
265        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
266        runtime --no-jit option is given.
268    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
269        ovector, the return from the function was zero, implying that there were
270        other matches that did not fit. The correct "exactly full" value is now
271        returned.
273    6.  If a subpattern that was called recursively or as a subroutine contained
274        (*PRUNE) or any other control that caused it to give a non-standard return,
275        invalid errors such as "Error -26 (nested recursion at the same subject
276        position)" or even infinite loops could occur.
278    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
279        computing the minimum length on reaching *ACCEPT, and so ended up with the
280        wrong value of 1 rather than 0. Further investigation indicates that
281        computing a minimum subject length in the presence of *ACCEPT is difficult
282        (think back references, subroutine calls), and so I have changed the code
283        so that no minimum is registered for a pattern that contains *ACCEPT.
285    8.  If (*THEN) was present in the first (true) branch of a conditional group,
286        it was not handled as intended. [But see 16 below.]
288    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
289        Sheri Pierce.
291    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
292        the first byte in a match must be "a".
294    11. Change 17 for 8.13 increased the recursion depth for patterns like
295        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
296        pattern contains any instances of (*THEN). If it does not, the old
297        optimizations are restored. It would be nice to do this on a per-group
298        basis, but at the moment that is not feasible.
300    12. In some environments, the output of pcretest -C is CRLF terminated. This
301        broke RunTest's code that checks for the link size. A single white space
302        character after the value is now allowed for.
304    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
305        For "fr", it uses the Windows-specific input and output files.
307    14. If (*THEN) appeared in a group that was called recursively or as a
308        subroutine, it did not work as intended. [But see next item.]
310    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
311        pattern fragments (but not containing any | characters). If A and B are
312        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
313        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
314        D. In other words, Perl considers parentheses that do not contain any |
315        characters to be part of a surrounding alternative, whereas PCRE was
316        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
317        differently. PCRE now behaves in the same way as Perl, except in the case
318        of subroutine/recursion calls such as (?1) which have in any case always
319        been different (but PCRE had them first :-).
321    16. Related to 15 above: Perl does not treat the | in a conditional group as
322        creating alternatives. Such a group is treated in the same way as an
323        ordinary group without any | characters when processing (*THEN). PCRE has
324        been changed to match Perl's behaviour.
326    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
327        RunGrepTest script failed.
329    18. Change 22 for version 13 caused atomic groups to use more stack. This is
330        inevitable for groups that contain captures, but it can lead to a lot of
331        stack use in large patterns. The old behaviour has been restored for atomic
332        groups that do not contain any capturing parentheses.
334    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
335        suppress the check for a minimum subject length at run time. (If it was
336        given to pcre_exec() or pcre_dfa_exec() it did work.)
338    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
339        fail to work when decoding hex characters in data strings in EBCDIC
340        environments.
342    21. It appears that in at least one Mac OS environment, the isxdigit() function
343        is implemented as a macro that evaluates to its argument more than once,
344        contravening the C 90 Standard (I haven't checked a later standard). There
345        was an instance in pcretest which caused it to go wrong when processing
346        \x{...} escapes in subject strings. The has been rewritten to avoid using
347        things like p++ in the argument of isxdigit().
350    Version 8.13 16-Aug-2011
351    ------------------------
353    1.  The Unicode data tables have been updated to Unicode 6.0.0.
355    2.  Two minor typos in pcre_internal.h have been fixed.
357    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
358        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
359        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
361    4.  There were a number of related bugs in the code for matching backrefences
362        caselessly in UTF-8 mode when codes for the characters concerned were
363        different numbers of bytes. For example, U+023A and U+2C65 are an upper
364        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
365        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
366        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
367        2-byte code at the end of the subject (it thought there wasn't enough data
368        left).
370    5.  Comprehensive information about what went wrong is now returned by
371        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
372        as the output vector has at least 2 elements. The offset of the start of
373        the failing character and a reason code are placed in the vector.
375    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
376        now returned is for the first byte of the failing character, instead of the
377        last byte inspected. This is an incompatible change, but I hope it is small
378        enough not to be a problem. It makes the returned offset consistent with
379        pcre_exec() and pcre_dfa_exec().
381    7.  pcretest now gives a text phrase as well as the error number when
382        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
383        failure, the offset and reason code are output.
385    8.  When \R was used with a maximizing quantifier it failed to skip backwards
386        over a \r\n pair if the subsequent match failed. Instead, it just skipped
387        back over a single character (\n). This seems wrong (because it treated the
388        two characters as a single entity when going forwards), conflicts with the
389        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
390        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
391        has been changed.
393    9.  Some internal refactoring has changed the processing so that the handling
394        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
395        time (the PCRE_DOTALL option was changed this way some time ago: version
396        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
397        which was always a bit of a fudge. It also means that there is one less
398        argument for the match() function, which reduces its stack requirements
399        slightly. This change also fixes an incompatibility with Perl: the pattern
400        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
402    10. More internal refactoring has drastically reduced the number of recursive
403        calls to match() for possessively repeated groups such as (abc)++ when
404        using pcre_exec().
406    11. While implementing 10, a number of bugs in the handling of groups were
407        discovered and fixed:
409        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
410        (a|)*(?1) gave a compile-time internal error.
411        ((a|)+)+  did not notice that the outer group could match an empty string.
412        (^a|^)+   was not marked as anchored.
413        (.*a|.*)+ was not marked as matching at start or after a newline.
415    12. Yet more internal refactoring has removed another argument from the match()
416        function. Special calls to this function are now indicated by setting a
417        value in a variable in the "match data" data block.
419    13. Be more explicit in pcre_study() instead of relying on "default" for
420        opcodes that mean there is no starting character; this means that when new
421        ones are added and accidentally left out of pcre_study(), testing should
422        pick them up.
424    14. The -s option of pcretest has been documented for ages as being an old
425        synonym of -m (show memory usage). I have changed it to mean "force study
426        for every regex", that is, assume /S for every regex. This is similar to -i
427        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
428        using it. It makes it easier to run collections of tests with and without
429        study enabled, and thereby test pcre_study() more easily. All the standard
430        tests are now run with and without -s (but some patterns can be marked as
431        "never study" - see 20 below).
433    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
434        restoration of the capturing data to the outer values was not happening
435        correctly.
437    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
438        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
439        pattern had matched an empty string, and so incorrectly returned a no
440        match.
442    17. There was optimizing code for the last branch of non-capturing parentheses,
443        and also for the obeyed branch of a conditional subexpression, which used
444        tail recursion to cut down on stack usage. Unfortunately, now that there is
445        the possibility of (*THEN) occurring in these branches, tail recursion is
446        no longer possible because the return has to be checked for (*THEN). These
447        two optimizations have therefore been removed. [But see 8.20/11 above.]
449    18. If a pattern containing \R was studied, it was assumed that \R always
450        matched two bytes, thus causing the minimum subject length to be
451        incorrectly computed because \R can also match just one byte.
453    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
454        was incorrectly computed.
456    20. If /S is present twice on a test pattern in pcretest input, it now
457        *disables* studying, thereby overriding the use of -s on the command line
458        (see 14 above). This is necessary for one or two tests to keep the output
459        identical in both cases.
461    21. When (*ACCEPT) was used in an assertion that matched an empty string and
462        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
464    22. When an atomic group that contained a capturing parenthesis was
465        successfully matched, but the branch in which it appeared failed, the
466        capturing was not being forgotten if a higher numbered group was later
467        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
468        group 1 to "a", when in fact it should be unset. This applied to multi-
469        branched capturing and non-capturing groups, repeated or not, and also to
470        positive assertions (capturing in negative assertions does not happen
471        in PCRE) and also to nested atomic groups.
473    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
474        subject after a captured substring, to make it easier to tell which of a
475        number of identical substrings has been captured.
477    24. The way atomic groups are processed by pcre_exec() has been changed so that
478        if they are repeated, backtracking one repetition now resets captured
479        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
480        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
481        "aaa". Previously, it would have been "a". As part of this code
482        refactoring, the way recursive calls are handled has also been changed.
484    25. If an assertion condition captured any substrings, they were not passed
485        back unless some other capturing happened later. For example, if
486        (?(?=(a))a) was matched against "a", no capturing was returned.
488    26. When studying a pattern that contained subroutine calls or assertions,
489        the code for finding the minimum length of a possible match was handling
490        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
491        group 1 called group 2 while simultaneously a separate group 2 called group
492        1). A stack overflow occurred in this case. I have fixed this by limiting
493        the recursion depth to 10.
495    27. Updated RunTest.bat in the distribution to the version supplied by Tom
496        Fortmann. This supports explicit test numbers on the command line, and has
497        argument validation and error reporting.
499    28. An instance of \X with an unlimited repeat could fail if at any point the
500        first character it looked at was a mark character.
502    29. Some minor code refactoring concerning Unicode properties and scripts
503        should reduce the stack requirement of match() slightly.
505    30. Added the '=' option to pcretest to check the setting of unused capturing
506        slots at the end of the pattern, which are documented as being -1, but are
507        not included in the return count.
509    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
510        compiled something random. Now it gives a compile-time error (as does
511        Perl).
513    32. A *MARK encountered during the processing of a positive assertion is now
514        recorded and passed back (compatible with Perl).
516    33. If --only-matching or --colour was set on a pcregrep call whose pattern
517        had alternative anchored branches, the search for a second match in a line
518        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
519        matched the line "0102" twice. The same bug affected patterns that started
520        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
521        twice.
523    34. Previously, PCRE did not allow quantification of assertions. However, Perl
524        does, and because of capturing effects, quantifying parenthesized
525        assertions may at times be useful. Quantifiers are now allowed for
526        parenthesized assertions.
528    35. A minor code tidy in pcre_compile() when checking options for \R usage.
530    36. \g was being checked for fancy things in a character class, when it should
531        just be a literal "g".
533    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
534        appearance of a nested POSIX class supersedes an apparent external class.
535        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
536        unescaped square brackets may also appear as part of class names. For
537        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
538        more like Perl. (But see 8.20/1 above.)
540    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
541        was because it thought it was \N{name}, which is not supported).
543    39. Add minix to OS list not supporting the -S option in pcretest.
545    40. PCRE tries to detect cases of infinite recursion at compile time, but it
546        cannot analyze patterns in sufficient detail to catch mutual recursions
547        such as ((?1))((?2)). There is now a runtime test that gives an error if a
548        subgroup is called recursively as a subpattern for a second time at the
549        same position in the subject string. In previous releases this might have
550        been caught by the recursion limit, or it might have run out of stack.
552    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
553        happen only once. PCRE was, however incorrectly giving a compile time error
554        "recursive call could loop indefinitely" because it cannot analyze the
555        pattern in sufficient detail. The compile time test no longer happens when
556        PCRE is compiling a conditional subpattern, but actual runaway loops are
557        now caught at runtime (see 40 above).
559    42. It seems that Perl allows any characters other than a closing parenthesis
560        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
561        has been changed to be the same.
563    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
564        as not to get warnings when autogen.sh is called. Also changed
565        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
567    44. To help people who use pcregrep to scan files containing exceedingly long
568        lines, the following changes have been made:
570        (a) The default value of the buffer size parameter has been increased from
571            8K to 20K. (The actual buffer used is three times this size.)
573        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
574            PCRE is built.
576        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
577            to be set at run time.
579        (d) Numerical values in pcregrep options can be followed by K or M, for
580            example --buffer-size=50K.
582        (e) If a line being scanned overflows pcregrep's buffer, an error is now
583            given and the return code is set to 2.
585    45. Add a pointer to the latest mark to the callout data block.
587    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
588        partial match of an empty string instead of no match. This was specific to
589        the use of ".".
591    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
592        complete match instead of a partial match. This bug was dependent on both
593        the PCRE_UTF8 and PCRE_DOTALL options being set.
595    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
596        starting byte set, because \b was not being ignored.
599    Version 8.12 15-Jan-2011
600    ------------------------
602    1.  Fixed some typos in the markup of the man pages, and wrote a script that
603        checks for such things as part of the documentation building process.
605    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
606        --match-limit and --recursion-limit options (added for 8.11). In
607        particular, this made one of the standard tests fail. (The integer value
608        went into the wrong half of a long int.)
610    3.  If the --colour option was given to pcregrep with -v (invert match), it
611        did strange things, either producing crazy output, or crashing. It should,
612        of course, ignore a request for colour when reporting lines that do not
613        match.
615    4.  Another pcregrep bug caused similar problems if --colour was specified with
616        -M (multiline) and the pattern match finished with a line ending.
618    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
619        matched in multiline mode, the following line was shown as part of the
620        match. This seems wrong, so I have changed it.
622    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
623        the check for further matches in the same line (so they could be coloured)
624        to overrun the end of the current line. If another match was found, it was
625        incorrectly shown (and then shown again when found in the next line).
627    7.  If pcregrep was compiled under Windows, there was a reference to the
628        function pcregrep_exit() before it was defined. I am assuming this was
629        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
630        reported by a user. I've moved the definition above the reference.
633    Version 8.11 10-Dec-2010
634    ------------------------
636    1.  (*THEN) was not working properly if there were untried alternatives prior
637        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
638        backtracked to try for "b" instead of moving to the next alternative branch
639        at the same level (in this case, to look for "c"). The Perl documentation
640        is clear that when (*THEN) is backtracked onto, it goes to the "next
641        alternative in the innermost enclosing group".
643    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
644        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
645        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
646        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
647        (*THEN).
649    3.  If \s appeared in a character class, it removed the VT character from
650        the class, even if it had been included by some previous item, for example
651        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
652        of \s, but is part of the POSIX "space" class.)
654    4.  A partial match never returns an empty string (because you can always
655        match an empty string at the end of the subject); however the checking for
656        an empty string was starting at the "start of match" point. This has been
657        changed to the "earliest inspected character" point, because the returned
658        data for a partial match starts at this character. This means that, for
659        example, /(?<=abc)def/ gives a partial match for the subject "abc"
660        (previously it gave "no match").
662    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
663        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
664        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
665        has an implication that the given string is incomplete (because a partial
666        match is preferred over a full match). For this reason, these items now
667        give a partial match in this situation. [Aside: previously, the one case
668        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
669        match rather than a full match, which was wrong by the old rules, but is
670        now correct.]
672    6.  There was a bug in the handling of #-introduced comments, recognized when
673        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
674        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
675        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
676        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
677        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
678        places in pcre_compile().
680    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
681        comments when looking ahead for named forward references to subpatterns,
682        the only newline sequence it recognized was NL. It now handles newlines
683        according to the set newline convention.
685    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
686        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
687        cater for a lack of strerror(). These oversights have been fixed.
689    9.  Added --match-limit and --recursion-limit to pcregrep.
691    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
693    11. When the -o option was used, pcregrep was setting a return code of 1, even
694        when matches were found, and --line-buffered was not being honoured.
696    12. Added an optional parentheses number to the -o and --only-matching options
697        of pcregrep.
699    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
700        can match an empty string. The code to do it in pcretest and pcredemo
701        needed fixing:
703        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
704            only one byte after an empty string match just before CRLF (this case
705            just got forgotten; "any" and "anycrlf" were OK).
707        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
708            mode when an empty string match preceded an ASCII character followed by
709            a non-ASCII character. (The code for advancing by one character rather
710            than one byte was nonsense.)
712        (c) The pcredemo.c sample program did not have any code at all to handle
713            the cases when CRLF is a valid newline sequence.
715    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
716        as a starting offset was within the subject string. There is now a new
717        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
718        negative or greater than the length of the string. In order to test this,
719        pcretest is extended to allow the setting of negative starting offsets.
721    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
722        starting offset points to the beginning of a UTF-8 character was
723        unnecessarily clumsy. I tidied it up.
725    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
726        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
728    17. Nobody had reported that the --include_dir option, which was added in
729        release 7.7 should have been called --include-dir (hyphen, not underscore)
730        for compatibility with GNU grep. I have changed it to --include-dir, but
731        left --include_dir as an undocumented synonym, and the same for
732        --exclude-dir, though that is not available in GNU grep, at least as of
733        release 2.5.4.
735    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
736        characters from a string of bytes) have been redefined so as not to use
737        loops, in order to improve performance in some environments. At the same
738        time, I abstracted some of the common code into auxiliary macros to save
739        repetition (this should not affect the compiled code).
741    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
742        compile-time error is now given if \c is not followed by an ASCII
743        character, that is, a byte less than 128. (In EBCDIC mode, the code is
744        different, and any byte value is allowed.)
746    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
747        START_OPTIMIZE option, which is now allowed at compile time - but just
748        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
749        to pcregrep and other applications that have no direct access to PCRE
750        options. The new /Y option in pcretest sets this option when calling
751        pcre_compile().
753    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
754        back references. Groups containing recursive back references were forced to
755        be atomic by that change, but in the case of named groups, the amount of
756        memory required was incorrectly computed, leading to "Failed: internal
757        error: code overflow". This has been fixed.
759    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
760        pcretest.c, to avoid build problems in some Borland environments.
763    Version 8.10 25-Jun-2010
764    ------------------------
766    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
767        THEN.
769    2.  (*ACCEPT) was not working when inside an atomic group.
771    3.  Inside a character class, \B is treated as a literal by default, but
772        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
773        causes the error). The code is unchanged, but I tidied the documentation.
775    4.  Inside a character class, PCRE always treated \R and \X as literals,
776        whereas Perl faults them if its -w option is set. I have changed PCRE so
777        that it faults them when PCRE_EXTRA is set.
779    5.  Added support for \N, which always matches any character other than
780        newline. (It is the same as "." when PCRE_DOTALL is not set.)
782    6.  When compiling pcregrep with newer versions of gcc which may have
783        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
784        declared with attribute warn_unused_result" were given. Just casting the
785        result to (void) does not stop the warnings; a more elaborate fudge is
786        needed. I've used a macro to implement this.
788    7.  Minor change to pcretest.c to avoid a compiler warning.
790    8.  Added four artifical Unicode properties to help with an option to make
791        \s etc use properties (see next item). The new properties are: Xan
792        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
794    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
795        use Unicode properties. (*UCP) at the start of a pattern can be used to set
796        this option. Modified pcretest to add /W to test this facility. Added
797        REG_UCP to make it available via the POSIX interface.
799    10. Added --line-buffered to pcregrep.
801    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
802        studied, and the match started with a letter with a code point greater than
803        127 whose first byte was different to the first byte of the other case of
804        the letter, the other case of this starting letter was not recognized
805        (#976).
807    12. If a pattern that was studied started with a repeated Unicode property
808        test, for example, \p{Nd}+, there was the theoretical possibility of
809        setting up an incorrect bitmap of starting bytes, but fortunately it could
810        not have actually happened in practice until change 8 above was made (it
811        added property types that matched character-matching opcodes).
813    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
814        possible starting bytes for non-anchored patterns.
816    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
817        \R, and also a number of cases that involve Unicode properties, both
818        explicit and implicit when PCRE_UCP is set.
820    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
821        input, it could crash or give wrong results if characters with values
822        greater than 0xc0 were present in the subject string. (Detail: it assumed
823        UTF-8 input when processing these items.)
825    16. Added a lot of (int) casts to avoid compiler warnings in systems where
826        size_t is 64-bit (#991).
828    17. Added a check for running out of memory when PCRE is compiled with
829        --disable-stack-for-recursion (#990).
831    18. If the last data line in a file for pcretest does not have a newline on
832        the end, a newline was missing in the output.
834    19. The default pcre_chartables.c file recognizes only ASCII characters (values
835        less than 128) in its various bitmaps. However, there is a facility for
836        generating tables according to the current locale when PCRE is compiled. It
837        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
838        characters, are recognized by isspace() and therefore were getting set in
839        these tables, and indeed these tables seem to approximate to ISO 8859. This
840        caused a problem in UTF-8 mode when pcre_study() was used to create a list
841        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
842        which of course cannot start UTF-8 characters. I have changed the code so
843        that only real ASCII characters (less than 128) and the correct starting
844        bytes for UTF-8 encodings are set for characters greater than 127 when in
845        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
846        altogether.)
848    20. Added the /T option to pcretest so as to be able to run tests with non-
849        standard character tables, thus making it possible to include the tests
850        used for 19 above in the standard set of tests.
852    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
853        reference to a subpattern the other side of a comment that contains an
854        opening parenthesis caused either an internal compiling error, or a
855        reference to the wrong subpattern.
858    Version 8.02 19-Mar-2010
859    ------------------------
861    1.  The Unicode data tables have been updated to Unicode 5.2.0.
863    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
864        configured.
866    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
867        original author of that file, following a query about its status.
869    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
870        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
872    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
873        quantifier applied to a forward-referencing subroutine call, could compile
874        incorrect code or give the error "internal error: previously-checked
875        referenced subpattern not found".
877    6.  Both MS Visual Studio and Symbian OS have problems with initializing
878        variables to point to external functions. For these systems, therefore,
879        pcre_malloc etc. are now initialized to local functions that call the
880        relevant global functions.
882    7.  There were two entries missing in the vectors called coptable and poptable
883        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
884        I've fixed the data, and added a kludgy way of testing at compile time that
885        the lengths are correct (equal to the number of opcodes).
887    8.  Following on from 7, I added a similar kludge to check the length of the
888        eint vector in pcreposix.c.
890    9.  Error texts for pcre_compile() are held as one long string to avoid too
891        much relocation at load time. To find a text, the string is searched,
892        counting zeros. There was no check for running off the end of the string,
893        which could happen if a new error number was added without updating the
894        string.
896    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
898    11. \K was not working if it appeared in an atomic group or in a group that
899        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
900        \K is "not well defined" if used in an assertion. PCRE now accepts it if
901        the assertion is positive, but not if it is negative.
903    12. Change 11 fortuitously reduced the size of the stack frame used in the
904        "match()" function of pcre_exec.c by one pointer. Forthcoming
905        implementation of support for (*MARK) will need an extra pointer on the
906        stack; I have reserved it now, so that the stack frame size does not
907        decrease.
909    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
910        item in branch that calls a recursion is a subroutine call - as in the
911        second branch in the above example - was incorrectly given the compile-
912        time error "recursive call could loop indefinitely" because pcre_compile()
913        was not correctly checking the subroutine for matching a non-empty string.
915    14. The checks for overrunning compiling workspace could trigger after an
916        overrun had occurred. This is a "should never occur" error, but it can be
917        triggered by pathological patterns such as hundreds of nested parentheses.
918        The checks now trigger 100 bytes before the end of the workspace.
920    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
923    Version 8.01 19-Jan-2010
924    ------------------------
926    1.  If a pattern contained a conditional subpattern with only one branch (in
927        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
928        computed the wrong minimum data length (which is of course zero for such
929        subpatterns). This could cause incorrect "no match" results.
931    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
932        the pattern is reset in the first branch, pcre_compile() failed with
933        "internal error: code overflow at offset...". This happened only when
934        the reset was to the original external option setting. (An optimization
935        abstracts leading options settings into an external setting, which was the
936        cause of this.)
938    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
939        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
940        assertion pattern did not match (meaning that the assertion was true), it
941        was incorrectly treated as false if the SKIP had been reached during the
942        matching. This also applied to assertions used as conditions.
944    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
945        assertion subpattern, including such a pattern used as a condition,
946        unpredictable results occurred, instead of the error return
949    5.  The C++ GlobalReplace function was not working like Perl for the special
950        situation when an empty string is matched. It now does the fancy magic
951        stuff that is necessary.
953    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
954        removed. (These were left over from very, very early versions of PCRE.)
956    7.  Some cosmetic changes to the code to make life easier when compiling it
957        as part of something else:
959        (a) Change DEBUG to PCRE_DEBUG.
961        (b) In pcre_compile(), rename the member of the "branch_chain" structure
962            called "current" as "current_branch", to prevent a collision with the
963            Linux macro when compiled as a kernel module.
965        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
966            prevent a collision with the Linux macro when compiled as a kernel
967            module.
969    8.  In pcre_compile() there are some checks for integer overflows that used to
970        cast potentially large values to (double). This has been changed to that
971        when building, a check for int64_t is made, and if it is found, it is used
972        instead, thus avoiding the use of floating point arithmetic. (There is no
973        other use of FP in PCRE.) If int64_t is not found, the fallback is to
974        double.
976    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
977        2005 (difference between two addresses compared to an unsigned value).
979    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
980        custom one, because of the following reported problem in Windows:
982          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
983              under Win32.
984          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
985              therefore missing the function definition.
986          - The compiler thus generates a "C" signature for the test function.
987          - The linker fails to find the "C" function.
988          - PCRE fails to configure if asked to do so against libbz2.
990    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
991        messages were output:
993          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
994          rerunning libtoolize, to keep the correct libtool macros in-tree.
995          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
997        I have done both of these things.
999    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1000        most of the time, it *can* run out if it is given a pattern that contains a
1001        runaway infinite recursion. I updated the discussion in the pcrestack man
1002        page.
1004    13. Now that we have gone to the x.xx style of version numbers, the minor
1005        version may start with zero. Using 08 or 09 is a bad idea because users
1006        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1007        interpreted as invalid octal numbers. I've updated the previous comment in
1008        configure.ac, and also added a check that gives an error if 08 or 09 are
1009        used.
1011    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1012        causing partial matching to fail when the end of the subject matched \W
1013        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1015    15. There were some discrepancies between the declarations in pcre_internal.h
1016        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1017        their definitions. The declarations used "const uschar *" and the
1018        definitions used USPTR. Even though USPTR is normally defined as "const
1019        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1020        reported that: "This difference in casting confuses some C++ compilers, for
1021        example, SunCC recognizes above declarations as different functions and
1022        generates broken code for hbpcre." I have changed the declarations to use
1023        USPTR.
1025    16. GNU libtool is named differently on some systems. The autogen.sh script now
1026        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1027        (FreeBSD).
1029    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1030        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1031        comment: "Figure out how to create a longlong from a string: strtoll and
1032        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1033        instance, but it only takes 2 args instead of 3!"
1035    18. A subtle bug concerned with back references has been fixed by a change of
1036        specification, with a corresponding code fix. A pattern such as
1037        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1038        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1039        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1040        same bug. Such groups have to be quantified to be useful, or contained
1041        inside another quantified group. (If there's no repetition, the reference
1042        can never match.) The problem arises because, having left the group and
1043        moved on to the rest of the pattern, a later failure that backtracks into
1044        the group uses the captured value from the final iteration of the group
1045        rather than the correct earlier one. I have fixed this in PCRE by forcing
1046        any group that contains a reference to itself to be an atomic group; that
1047        is, there cannot be any backtracking into it once it has completed. This is
1048        similar to recursive and subroutine calls.
1051    Version 8.00 19-Oct-09
1052    ----------------------
1054    1.  The table for translating pcre_compile() error codes into POSIX error codes
1055        was out-of-date, and there was no check on the pcre_compile() error code
1056        being within the table. This could lead to an OK return being given in
1057        error.
1059    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1060        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1061        in a Windows environment.
1063    3.  The pcregrep --count option prints the count for each file even when it is
1064        zero, as does GNU grep. However, pcregrep was also printing all files when
1065        --files-with-matches was added. Now, when both options are given, it prints
1066        counts only for those files that have at least one match. (GNU grep just
1067        prints the file name in this circumstance, but including the count seems
1068        more useful - otherwise, why use --count?) Also ensured that the
1069        combination -clh just lists non-zero counts, with no names.
1071    4.  The long form of the pcregrep -F option was incorrectly implemented as
1072        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1073        but it seems right to fix it, and I didn't think it was worth preserving
1074        the old behaviour.
1076    5.  The command line items --regex=pattern and --regexp=pattern were not
1077        recognized by pcregrep, which required --regex pattern or --regexp pattern
1078        (with a space rather than an '='). The man page documented the '=' forms,
1079        which are compatible with GNU grep; these now work.
1081    6.  No libpcreposix.pc file was created for pkg-config; there was just
1082        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1084    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1085        when UCP support is not needed, by modifying the Python script that
1086        generates it from Unicode data files. This should not matter if the module
1087        is correctly used as a library, but I received one complaint about 50K of
1088        unwanted data. My guess is that the person linked everything into his
1089        program rather than using a library. Anyway, it does no harm.
1091    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1092        was a minimum greater than 1 for a wide character in a possessive
1093        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1094        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1095        character. Chaos in the form of incorrect output or a compiling loop could
1096        result.
1098    9.  The restrictions on what a pattern can contain when partial matching is
1099        requested for pcre_exec() have been removed. All patterns can now be
1100        partially matched by this function. In addition, if there are at least two
1101        slots in the offset vector, the offset of the earliest inspected character
1102        for the match and the offset of the end of the subject are set in them when
1103        PCRE_ERROR_PARTIAL is returned.
1105    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1106        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1107        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1108        and may be more useful for multi-segment matching.
1110    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1111        used to be given if ever the end of the subject was reached; now it is
1112        given only if matching could not proceed because another character was
1113        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1114        string "Z", which now yields "no match" instead of "partial match". In the
1115        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1116        final character ended with (*FAIL).
1118    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1119        if the pattern had a "must contain" character that was already found in the
1120        earlier partial match, unless partial matching was again requested. For
1121        example, with the pattern /dog.(body)?/, the "must contain" character is
1122        "g". If the first part-match was for the string "dog", restarting with
1123        "sbody" failed. This bug has been fixed.
1125    13. The string returned by pcre_dfa_exec() after a partial match has been
1126        changed so that it starts at the first inspected character rather than the
1127        first character of the match. This makes a difference only if the pattern
1128        starts with a lookbehind assertion or \b or \B (\K is not supported by
1129        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1130        matching functions compatible, and I think it's the right thing to do.
1132    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1133        so that the demonstration program is easily available in environments where
1134        PCRE has not been installed from source.
1136    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1137        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1138        library.
1140    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1141        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1142        is not the first non-POSIX option to be added. Clearly some people find
1143        these options useful.
1145    17. If a caller to the POSIX matching function regexec() passes a non-zero
1146        value for nmatch with a NULL value for pmatch, the value of
1147        nmatch is forced to zero.
1149    18. RunGrepTest did not have a test for the availability of the -u option of
1150        the diff command, as RunTest does. It now checks in the same way as
1151        RunTest, and also checks for the -b option.
1153    19. If an odd number of negated classes containing just a single character
1154        interposed, within parentheses, between a forward reference to a named
1155        subpattern and the definition of the subpattern, compilation crashed with
1156        an internal error, complaining that it could not find the referenced
1157        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1158        [The bug was that it was starting one character too far in when skipping
1159        over the character class, thus treating the ] as data rather than
1160        terminating the class. This meant it could skip too much.]
1162    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1163        /g option in pcretest when the pattern contains \K, which makes it possible
1164        to have an empty string match not at the start, even when the pattern is
1165        anchored. Updated pcretest and pcredemo to use this option.
1167    21. If the maximum number of capturing subpatterns in a recursion was greater
1168        than the maximum at the outer level, the higher number was returned, but
1169        with unset values at the outer level. The correct (outer level) value is
1170        now given.
1172    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1173        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1174        make it do so. The string so far is captured, making this feature
1175        compatible with Perl.
1177    23. The tests have been re-organized, adding tests 11 and 12, to make it
1178        possible to check the Perl 5.10 features against Perl 5.10.
1180    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1181        pattern matches a fixed length string. PCRE did not allow this; now it
1182        does. Neither allows recursion.
1184    25. I finally figured out how to implement a request to provide the minimum
1185        length of subject string that was needed in order to match a given pattern.
1186        (It was back references and recursion that I had previously got hung up
1187        on.) This code has now been added to pcre_study(); it finds a lower bound
1188        to the length of subject needed. It is not necessarily the greatest lower
1189        bound, but using it to avoid searching strings that are too short does give
1190        some useful speed-ups. The value is available to calling programs via
1191        pcre_fullinfo().
1193    26. While implementing 25, I discovered to my embarrassment that pcretest had
1194        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1195        study optimizations had never been tested with that matching function.
1196        Oops. What is worse, even when it was passed study data, there was a bug in
1197        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1198        were also very few tests of studied patterns with pcre_dfa_exec().
1200    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1201        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1202        on the other side of the coin, they are no longer allowed to have different
1203        names, because these cannot be distinguished in PCRE, and this has caused
1204        confusion. (This is a difference from Perl.)
1206    28. When duplicate subpattern names are present (necessarily with different
1207        numbers, as required by 27 above), and a test is made by name in a
1208        conditional pattern, either for a subpattern having been matched, or for
1209        recursion in such a pattern, all the associated numbered subpatterns are
1210        tested, and the overall condition is true if the condition is true for any
1211        one of them. This is the way Perl works, and is also more like the way
1212        testing by number works.
1215    Version 7.9 11-Apr-09
1216  ---------------------  ---------------------
1218  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 1228  Version 7.9 xx-xxx-09
1228      but BOOL is not.      but BOOL is not.
1230  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1231      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1233  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
1234      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 94  Version 7.9 xx-xxx-09 Line 1305  Version 7.9 xx-xxx-09
1305  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1306      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1307      included within another project.      included within another project.
1309  24. Steven Van Ingelgem's patches to add more options to the CMake support,  24. Steven Van Ingelgem's patches to add more options to the CMake support,
1310      slightly modified by me:      slightly modified by me:
1312        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1313            not building pcregrep.            not building pcregrep.
1315        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1316            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1318  25. Forward references, both numeric and by name, in patterns that made use of  25. Forward references, both numeric and by name, in patterns that made use of
1319      duplicate group numbers, could behave incorrectly or give incorrect errors,      duplicate group numbers, could behave incorrectly or give incorrect errors,
1320      because when scanning forward to find the reference group, PCRE was not      because when scanning forward to find the reference group, PCRE was not
1321      taking into account the duplicate group numbers. A pattern such as      taking into account the duplicate group numbers. A pattern such as
1322      ^X(?3)(a)(?|(b)|(q))(Y) is an example.      ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1324    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1325        the feature of a custom pointer more persuasive (as requested by a user).
1327    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1328        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1329        pre-defined.
1331    28. Added support for (*UTF8) at the start of a pattern.
1333    29. Arrange for flags added by the "release type" setting in CMake to be shown
1334        in the configuration summary.
1337  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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