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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.00 ??-???-??  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.
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
68    6.  The Unicode data tables have been updated to Unicode 6.1.0.
71    Version 8.30 04-February-2012
72    -----------------------------
74    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
75        name is defined in ctype.h.
77    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
78        only in quite long subpatterns.
80    3.  Removed the function pcre_info(), which has been obsolete and deprecated
81        since it was replaced by pcre_fullinfo() in February 2000.
83    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
84        match a (*MARK), and the match failed at the start of the subject, a
85        reference to memory before the start of the subject could occur. This bug
86        was introduced by fix 17 of release 8.21.
88    5.  A reference to an unset group with zero minimum repetition was giving
89        totally wrong answers (in non-JavaScript-compatibility mode). For example,
90        /(another)?(\1?)test/ matched against "hello world test". This bug was
91        introduced in release 8.13.
93    6.  Add support for 16-bit character strings (a large amount of work involving
94        many changes and refactorings).
96    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
97        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
98        from a file.
100    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
101        rounding is not applied in this particular case).
103    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
104        if they appear, or are escaped, in patterns.
106    10. Get rid of a number of -Wunused-but-set-variable warnings.
108    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
109        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
110        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
111        also returns the mark "x". This bug applied to capturing parentheses,
112        non-capturing parentheses, and atomic parentheses. It also applied to some
113        assertions.
115    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
116        information out of configure.ac instead of relying on pcre.h.generic, which
117        is not stored in the repository.
119    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
120        -lreadline.
122    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
124    15. Applied Graycode's patch to put the top-level frame on the stack rather
125        than the heap when not using the stack for recursion. This gives a
126        performance improvement in many cases when recursion is not deep.
128    16. Experimental code added to "pcretest -C" to output the stack frame size.
131    Version 8.21 12-Dec-2011
132    ------------------------
134    1.  Updating the JIT compiler.
136    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
137        are added as well.
139    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
140        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
141        calling _pcre_jit_exec. Some extra comments are added.
143    4.  (*MARK) settings inside atomic groups that do not contain any capturing
144        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
145        was introduced by change 18 for 8.20.
147    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
148        ECMA-262 standard.
150    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
151        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
152        This bug was probably introduced by change 9 of 8.13.
154    7.  While fixing 6 above, I noticed that a number of other items were being
155        incorrectly rejected as "not fixed length". This arose partly because newer
156        opcodes had not been added to the fixed-length checking code. I have (a)
157        corrected the bug and added tests for these items, and (b) arranged for an
158        error to occur if an unknown opcode is encountered while checking for fixed
159        length instead of just assuming "not fixed length". The items that were
160        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
161        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
162        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
164    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
165        being incorrectly compiled and would have given unpredicatble results.
167    9.  A possessively repeated subpattern with minimum repeat count greater than
168        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
169        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
170        the first (A) could occur when it should not.
172    10. Add a cast and remove a redundant test from the code.
174    11. JIT should use pcre_malloc/pcre_free for allocation.
176    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
177        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
178        is anything other than /usr, -L is still shown).
180    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
182    14. Perl does not support \N without a following name in a [] class; PCRE now
183        also gives an error.
185    15. If a forward reference was repeated with an upper limit of around 2000,
186        it caused the error "internal error: overran compiling workspace". The
187        maximum number of forward references (including repeats) was limited by the
188        internal workspace, and dependent on the LINK_SIZE. The code has been
189        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
190        the default depends on LINK_SIZE. There is a new upper limit (for safety)
191        of around 200,000 forward references. While doing this, I also speeded up
192        the filling in of repeated forward references.
194    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
195        incorrectly expecting the subject to contain another "a" after the start.
197    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
198        in the match, the SKIP should be ignored. This was not happening; instead
199        the SKIP was being treated as NOMATCH. For patterns such as
200        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
201        tested.
203    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
204        now much more compatible with Perl, in particular in cases where the result
205        is a non-match for a non-anchored pattern. For example, if
206        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
207        "m", where previously it did not return a name. A side effect of this
208        change is that for partial matches, the last encountered mark name is
209        returned, as for non matches. A number of tests that were previously not
210        Perl-compatible have been moved into the Perl-compatible test files. The
211        refactoring has had the pleasing side effect of removing one argument from
212        the match() function, thus reducing its stack requirements.
214    19. If the /S+ option was used in pcretest to study a pattern using JIT,
215        subsequent uses of /S (without +) incorrectly behaved like /S+.
217    21. Retrieve executable code size support for the JIT compiler and fixing
218        some warnings.
220    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
221        not work when the shorter character appeared right at the end of the
222        subject string.
224    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
225        systems.
227    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
228        output it when the /M option is used in pcretest.
230    25. The CheckMan script was not being included in the distribution. Also, added
231        an explicit "perl" to run Perl scripts from the PrepareRelease script
232        because this is reportedly needed in Windows.
234    26. If study data was being save in a file and studying had not found a set of
235        "starts with" bytes for the pattern, the data written to the file (though
236        never used) was taken from uninitialized memory and so caused valgrind to
237        complain.
239    27. Updated RunTest.bat as provided by Sheri Pierce.
241    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
243    29. Computation of memory usage for the table of capturing group names was
244        giving an unnecessarily large value.
247    Version 8.20 21-Oct-2011
248    ------------------------
250    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
251        a POSIX class. After further experiments with Perl, which convinced me that
252        Perl has bugs and confusions, a closing square bracket is no longer allowed
253        in a POSIX name. This bug also affected patterns with classes that started
254        with full stops.
256    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
257        captured substring, but while checking the failing first alternative,
258        substring 1 is temporarily captured. If the output vector supplied to
259        pcre_exec() was not big enough for this capture, the yield of the function
260        was still zero ("insufficient space for captured substrings"). This cannot
261        be totally fixed without adding another stack variable, which seems a lot
262        of expense for a edge case. However, I have improved the situation in cases
263        such as /(a)(b)x|abc/ matched against "abc", where the return code
264        indicates that fewer than the maximum number of slots in the ovector have
265        been set.
267    3.  Related to (2) above: when there are more back references in a pattern than
268        slots in the output vector, pcre_exec() uses temporary memory during
269        matching, and copies in the captures as far as possible afterwards. It was
270        using the entire output vector, but this conflicts with the specification
271        that only 2/3 is used for passing back captured substrings. Now it uses
272        only the first 2/3, for compatibility. This is, of course, another edge
273        case.
275    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
276        main code base, and can be used by building with --enable-jit. When this is
277        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
278        runtime --no-jit option is given.
280    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
281        ovector, the return from the function was zero, implying that there were
282        other matches that did not fit. The correct "exactly full" value is now
283        returned.
285    6.  If a subpattern that was called recursively or as a subroutine contained
286        (*PRUNE) or any other control that caused it to give a non-standard return,
287        invalid errors such as "Error -26 (nested recursion at the same subject
288        position)" or even infinite loops could occur.
290    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
291        computing the minimum length on reaching *ACCEPT, and so ended up with the
292        wrong value of 1 rather than 0. Further investigation indicates that
293        computing a minimum subject length in the presence of *ACCEPT is difficult
294        (think back references, subroutine calls), and so I have changed the code
295        so that no minimum is registered for a pattern that contains *ACCEPT.
297    8.  If (*THEN) was present in the first (true) branch of a conditional group,
298        it was not handled as intended. [But see 16 below.]
300    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
301        Sheri Pierce.
303    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
304        the first byte in a match must be "a".
306    11. Change 17 for 8.13 increased the recursion depth for patterns like
307        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
308        pattern contains any instances of (*THEN). If it does not, the old
309        optimizations are restored. It would be nice to do this on a per-group
310        basis, but at the moment that is not feasible.
312    12. In some environments, the output of pcretest -C is CRLF terminated. This
313        broke RunTest's code that checks for the link size. A single white space
314        character after the value is now allowed for.
316    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
317        For "fr", it uses the Windows-specific input and output files.
319    14. If (*THEN) appeared in a group that was called recursively or as a
320        subroutine, it did not work as intended. [But see next item.]
322    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
323        pattern fragments (but not containing any | characters). If A and B are
324        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
325        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
326        D. In other words, Perl considers parentheses that do not contain any |
327        characters to be part of a surrounding alternative, whereas PCRE was
328        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
329        differently. PCRE now behaves in the same way as Perl, except in the case
330        of subroutine/recursion calls such as (?1) which have in any case always
331        been different (but PCRE had them first :-).
333    16. Related to 15 above: Perl does not treat the | in a conditional group as
334        creating alternatives. Such a group is treated in the same way as an
335        ordinary group without any | characters when processing (*THEN). PCRE has
336        been changed to match Perl's behaviour.
338    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
339        RunGrepTest script failed.
341    18. Change 22 for version 13 caused atomic groups to use more stack. This is
342        inevitable for groups that contain captures, but it can lead to a lot of
343        stack use in large patterns. The old behaviour has been restored for atomic
344        groups that do not contain any capturing parentheses.
346    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
347        suppress the check for a minimum subject length at run time. (If it was
348        given to pcre_exec() or pcre_dfa_exec() it did work.)
350    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
351        fail to work when decoding hex characters in data strings in EBCDIC
352        environments.
354    21. It appears that in at least one Mac OS environment, the isxdigit() function
355        is implemented as a macro that evaluates to its argument more than once,
356        contravening the C 90 Standard (I haven't checked a later standard). There
357        was an instance in pcretest which caused it to go wrong when processing
358        \x{...} escapes in subject strings. The has been rewritten to avoid using
359        things like p++ in the argument of isxdigit().
362    Version 8.13 16-Aug-2011
363    ------------------------
365    1.  The Unicode data tables have been updated to Unicode 6.0.0.
367    2.  Two minor typos in pcre_internal.h have been fixed.
369    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
370        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
371        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
373    4.  There were a number of related bugs in the code for matching backrefences
374        caselessly in UTF-8 mode when codes for the characters concerned were
375        different numbers of bytes. For example, U+023A and U+2C65 are an upper
376        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
377        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
378        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
379        2-byte code at the end of the subject (it thought there wasn't enough data
380        left).
382    5.  Comprehensive information about what went wrong is now returned by
383        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
384        as the output vector has at least 2 elements. The offset of the start of
385        the failing character and a reason code are placed in the vector.
387    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
388        now returned is for the first byte of the failing character, instead of the
389        last byte inspected. This is an incompatible change, but I hope it is small
390        enough not to be a problem. It makes the returned offset consistent with
391        pcre_exec() and pcre_dfa_exec().
393    7.  pcretest now gives a text phrase as well as the error number when
394        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
395        failure, the offset and reason code are output.
397    8.  When \R was used with a maximizing quantifier it failed to skip backwards
398        over a \r\n pair if the subsequent match failed. Instead, it just skipped
399        back over a single character (\n). This seems wrong (because it treated the
400        two characters as a single entity when going forwards), conflicts with the
401        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
402        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
403        has been changed.
405    9.  Some internal refactoring has changed the processing so that the handling
406        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
407        time (the PCRE_DOTALL option was changed this way some time ago: version
408        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
409        which was always a bit of a fudge. It also means that there is one less
410        argument for the match() function, which reduces its stack requirements
411        slightly. This change also fixes an incompatibility with Perl: the pattern
412        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
414    10. More internal refactoring has drastically reduced the number of recursive
415        calls to match() for possessively repeated groups such as (abc)++ when
416        using pcre_exec().
418    11. While implementing 10, a number of bugs in the handling of groups were
419        discovered and fixed:
421        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
422        (a|)*(?1) gave a compile-time internal error.
423        ((a|)+)+  did not notice that the outer group could match an empty string.
424        (^a|^)+   was not marked as anchored.
425        (.*a|.*)+ was not marked as matching at start or after a newline.
427    12. Yet more internal refactoring has removed another argument from the match()
428        function. Special calls to this function are now indicated by setting a
429        value in a variable in the "match data" data block.
431    13. Be more explicit in pcre_study() instead of relying on "default" for
432        opcodes that mean there is no starting character; this means that when new
433        ones are added and accidentally left out of pcre_study(), testing should
434        pick them up.
436    14. The -s option of pcretest has been documented for ages as being an old
437        synonym of -m (show memory usage). I have changed it to mean "force study
438        for every regex", that is, assume /S for every regex. This is similar to -i
439        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
440        using it. It makes it easier to run collections of tests with and without
441        study enabled, and thereby test pcre_study() more easily. All the standard
442        tests are now run with and without -s (but some patterns can be marked as
443        "never study" - see 20 below).
445    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
446        restoration of the capturing data to the outer values was not happening
447        correctly.
449    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
450        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
451        pattern had matched an empty string, and so incorrectly returned a no
452        match.
454    17. There was optimizing code for the last branch of non-capturing parentheses,
455        and also for the obeyed branch of a conditional subexpression, which used
456        tail recursion to cut down on stack usage. Unfortunately, now that there is
457        the possibility of (*THEN) occurring in these branches, tail recursion is
458        no longer possible because the return has to be checked for (*THEN). These
459        two optimizations have therefore been removed. [But see 8.20/11 above.]
461    18. If a pattern containing \R was studied, it was assumed that \R always
462        matched two bytes, thus causing the minimum subject length to be
463        incorrectly computed because \R can also match just one byte.
465    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
466        was incorrectly computed.
468    20. If /S is present twice on a test pattern in pcretest input, it now
469        *disables* studying, thereby overriding the use of -s on the command line
470        (see 14 above). This is necessary for one or two tests to keep the output
471        identical in both cases.
473    21. When (*ACCEPT) was used in an assertion that matched an empty string and
474        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
476    22. When an atomic group that contained a capturing parenthesis was
477        successfully matched, but the branch in which it appeared failed, the
478        capturing was not being forgotten if a higher numbered group was later
479        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
480        group 1 to "a", when in fact it should be unset. This applied to multi-
481        branched capturing and non-capturing groups, repeated or not, and also to
482        positive assertions (capturing in negative assertions does not happen
483        in PCRE) and also to nested atomic groups.
485    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
486        subject after a captured substring, to make it easier to tell which of a
487        number of identical substrings has been captured.
489    24. The way atomic groups are processed by pcre_exec() has been changed so that
490        if they are repeated, backtracking one repetition now resets captured
491        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
492        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
493        "aaa". Previously, it would have been "a". As part of this code
494        refactoring, the way recursive calls are handled has also been changed.
496    25. If an assertion condition captured any substrings, they were not passed
497        back unless some other capturing happened later. For example, if
498        (?(?=(a))a) was matched against "a", no capturing was returned.
500    26. When studying a pattern that contained subroutine calls or assertions,
501        the code for finding the minimum length of a possible match was handling
502        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
503        group 1 called group 2 while simultaneously a separate group 2 called group
504        1). A stack overflow occurred in this case. I have fixed this by limiting
505        the recursion depth to 10.
507    27. Updated RunTest.bat in the distribution to the version supplied by Tom
508        Fortmann. This supports explicit test numbers on the command line, and has
509        argument validation and error reporting.
511    28. An instance of \X with an unlimited repeat could fail if at any point the
512        first character it looked at was a mark character.
514    29. Some minor code refactoring concerning Unicode properties and scripts
515        should reduce the stack requirement of match() slightly.
517    30. Added the '=' option to pcretest to check the setting of unused capturing
518        slots at the end of the pattern, which are documented as being -1, but are
519        not included in the return count.
521    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
522        compiled something random. Now it gives a compile-time error (as does
523        Perl).
525    32. A *MARK encountered during the processing of a positive assertion is now
526        recorded and passed back (compatible with Perl).
528    33. If --only-matching or --colour was set on a pcregrep call whose pattern
529        had alternative anchored branches, the search for a second match in a line
530        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
531        matched the line "0102" twice. The same bug affected patterns that started
532        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
533        twice.
535    34. Previously, PCRE did not allow quantification of assertions. However, Perl
536        does, and because of capturing effects, quantifying parenthesized
537        assertions may at times be useful. Quantifiers are now allowed for
538        parenthesized assertions.
540    35. A minor code tidy in pcre_compile() when checking options for \R usage.
542    36. \g was being checked for fancy things in a character class, when it should
543        just be a literal "g".
545    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
546        appearance of a nested POSIX class supersedes an apparent external class.
547        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
548        unescaped square brackets may also appear as part of class names. For
549        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
550        more like Perl. (But see 8.20/1 above.)
552    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
553        was because it thought it was \N{name}, which is not supported).
555    39. Add minix to OS list not supporting the -S option in pcretest.
557    40. PCRE tries to detect cases of infinite recursion at compile time, but it
558        cannot analyze patterns in sufficient detail to catch mutual recursions
559        such as ((?1))((?2)). There is now a runtime test that gives an error if a
560        subgroup is called recursively as a subpattern for a second time at the
561        same position in the subject string. In previous releases this might have
562        been caught by the recursion limit, or it might have run out of stack.
564    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
565        happen only once. PCRE was, however incorrectly giving a compile time error
566        "recursive call could loop indefinitely" because it cannot analyze the
567        pattern in sufficient detail. The compile time test no longer happens when
568        PCRE is compiling a conditional subpattern, but actual runaway loops are
569        now caught at runtime (see 40 above).
571    42. It seems that Perl allows any characters other than a closing parenthesis
572        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
573        has been changed to be the same.
575    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
576        as not to get warnings when autogen.sh is called. Also changed
577        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
579    44. To help people who use pcregrep to scan files containing exceedingly long
580        lines, the following changes have been made:
582        (a) The default value of the buffer size parameter has been increased from
583            8K to 20K. (The actual buffer used is three times this size.)
585        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
586            PCRE is built.
588        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
589            to be set at run time.
591        (d) Numerical values in pcregrep options can be followed by K or M, for
592            example --buffer-size=50K.
594        (e) If a line being scanned overflows pcregrep's buffer, an error is now
595            given and the return code is set to 2.
597    45. Add a pointer to the latest mark to the callout data block.
599    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
600        partial match of an empty string instead of no match. This was specific to
601        the use of ".".
603    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
604        complete match instead of a partial match. This bug was dependent on both
605        the PCRE_UTF8 and PCRE_DOTALL options being set.
607    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
608        starting byte set, because \b was not being ignored.
611    Version 8.12 15-Jan-2011
612    ------------------------
614    1.  Fixed some typos in the markup of the man pages, and wrote a script that
615        checks for such things as part of the documentation building process.
617    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
618        --match-limit and --recursion-limit options (added for 8.11). In
619        particular, this made one of the standard tests fail. (The integer value
620        went into the wrong half of a long int.)
622    3.  If the --colour option was given to pcregrep with -v (invert match), it
623        did strange things, either producing crazy output, or crashing. It should,
624        of course, ignore a request for colour when reporting lines that do not
625        match.
627    4.  Another pcregrep bug caused similar problems if --colour was specified with
628        -M (multiline) and the pattern match finished with a line ending.
630    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
631        matched in multiline mode, the following line was shown as part of the
632        match. This seems wrong, so I have changed it.
634    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
635        the check for further matches in the same line (so they could be coloured)
636        to overrun the end of the current line. If another match was found, it was
637        incorrectly shown (and then shown again when found in the next line).
639    7.  If pcregrep was compiled under Windows, there was a reference to the
640        function pcregrep_exit() before it was defined. I am assuming this was
641        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
642        reported by a user. I've moved the definition above the reference.
645    Version 8.11 10-Dec-2010
646    ------------------------
648    1.  (*THEN) was not working properly if there were untried alternatives prior
649        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
650        backtracked to try for "b" instead of moving to the next alternative branch
651        at the same level (in this case, to look for "c"). The Perl documentation
652        is clear that when (*THEN) is backtracked onto, it goes to the "next
653        alternative in the innermost enclosing group".
655    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
656        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
657        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
658        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
659        (*THEN).
661    3.  If \s appeared in a character class, it removed the VT character from
662        the class, even if it had been included by some previous item, for example
663        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
664        of \s, but is part of the POSIX "space" class.)
666    4.  A partial match never returns an empty string (because you can always
667        match an empty string at the end of the subject); however the checking for
668        an empty string was starting at the "start of match" point. This has been
669        changed to the "earliest inspected character" point, because the returned
670        data for a partial match starts at this character. This means that, for
671        example, /(?<=abc)def/ gives a partial match for the subject "abc"
672        (previously it gave "no match").
674    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
675        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
676        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
677        has an implication that the given string is incomplete (because a partial
678        match is preferred over a full match). For this reason, these items now
679        give a partial match in this situation. [Aside: previously, the one case
680        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
681        match rather than a full match, which was wrong by the old rules, but is
682        now correct.]
684    6.  There was a bug in the handling of #-introduced comments, recognized when
685        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
686        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
687        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
688        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
689        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
690        places in pcre_compile().
692    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
693        comments when looking ahead for named forward references to subpatterns,
694        the only newline sequence it recognized was NL. It now handles newlines
695        according to the set newline convention.
697    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
698        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
699        cater for a lack of strerror(). These oversights have been fixed.
701    9.  Added --match-limit and --recursion-limit to pcregrep.
703    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
705    11. When the -o option was used, pcregrep was setting a return code of 1, even
706        when matches were found, and --line-buffered was not being honoured.
708    12. Added an optional parentheses number to the -o and --only-matching options
709        of pcregrep.
711    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
712        can match an empty string. The code to do it in pcretest and pcredemo
713        needed fixing:
715        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
716            only one byte after an empty string match just before CRLF (this case
717            just got forgotten; "any" and "anycrlf" were OK).
719        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
720            mode when an empty string match preceded an ASCII character followed by
721            a non-ASCII character. (The code for advancing by one character rather
722            than one byte was nonsense.)
724        (c) The pcredemo.c sample program did not have any code at all to handle
725            the cases when CRLF is a valid newline sequence.
727    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
728        as a starting offset was within the subject string. There is now a new
729        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
730        negative or greater than the length of the string. In order to test this,
731        pcretest is extended to allow the setting of negative starting offsets.
733    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
734        starting offset points to the beginning of a UTF-8 character was
735        unnecessarily clumsy. I tidied it up.
737    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
738        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
740    17. Nobody had reported that the --include_dir option, which was added in
741        release 7.7 should have been called --include-dir (hyphen, not underscore)
742        for compatibility with GNU grep. I have changed it to --include-dir, but
743        left --include_dir as an undocumented synonym, and the same for
744        --exclude-dir, though that is not available in GNU grep, at least as of
745        release 2.5.4.
747    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
748        characters from a string of bytes) have been redefined so as not to use
749        loops, in order to improve performance in some environments. At the same
750        time, I abstracted some of the common code into auxiliary macros to save
751        repetition (this should not affect the compiled code).
753    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
754        compile-time error is now given if \c is not followed by an ASCII
755        character, that is, a byte less than 128. (In EBCDIC mode, the code is
756        different, and any byte value is allowed.)
758    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
759        START_OPTIMIZE option, which is now allowed at compile time - but just
760        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
761        to pcregrep and other applications that have no direct access to PCRE
762        options. The new /Y option in pcretest sets this option when calling
763        pcre_compile().
765    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
766        back references. Groups containing recursive back references were forced to
767        be atomic by that change, but in the case of named groups, the amount of
768        memory required was incorrectly computed, leading to "Failed: internal
769        error: code overflow". This has been fixed.
771    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
772        pcretest.c, to avoid build problems in some Borland environments.
775    Version 8.10 25-Jun-2010
776    ------------------------
778    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
779        THEN.
781    2.  (*ACCEPT) was not working when inside an atomic group.
783    3.  Inside a character class, \B is treated as a literal by default, but
784        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
785        causes the error). The code is unchanged, but I tidied the documentation.
787    4.  Inside a character class, PCRE always treated \R and \X as literals,
788        whereas Perl faults them if its -w option is set. I have changed PCRE so
789        that it faults them when PCRE_EXTRA is set.
791    5.  Added support for \N, which always matches any character other than
792        newline. (It is the same as "." when PCRE_DOTALL is not set.)
794    6.  When compiling pcregrep with newer versions of gcc which may have
795        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
796        declared with attribute warn_unused_result" were given. Just casting the
797        result to (void) does not stop the warnings; a more elaborate fudge is
798        needed. I've used a macro to implement this.
800    7.  Minor change to pcretest.c to avoid a compiler warning.
802    8.  Added four artifical Unicode properties to help with an option to make
803        \s etc use properties (see next item). The new properties are: Xan
804        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
806    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
807        use Unicode properties. (*UCP) at the start of a pattern can be used to set
808        this option. Modified pcretest to add /W to test this facility. Added
809        REG_UCP to make it available via the POSIX interface.
811    10. Added --line-buffered to pcregrep.
813    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
814        studied, and the match started with a letter with a code point greater than
815        127 whose first byte was different to the first byte of the other case of
816        the letter, the other case of this starting letter was not recognized
817        (#976).
819    12. If a pattern that was studied started with a repeated Unicode property
820        test, for example, \p{Nd}+, there was the theoretical possibility of
821        setting up an incorrect bitmap of starting bytes, but fortunately it could
822        not have actually happened in practice until change 8 above was made (it
823        added property types that matched character-matching opcodes).
825    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
826        possible starting bytes for non-anchored patterns.
828    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
829        \R, and also a number of cases that involve Unicode properties, both
830        explicit and implicit when PCRE_UCP is set.
832    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
833        input, it could crash or give wrong results if characters with values
834        greater than 0xc0 were present in the subject string. (Detail: it assumed
835        UTF-8 input when processing these items.)
837    16. Added a lot of (int) casts to avoid compiler warnings in systems where
838        size_t is 64-bit (#991).
840    17. Added a check for running out of memory when PCRE is compiled with
841        --disable-stack-for-recursion (#990).
843    18. If the last data line in a file for pcretest does not have a newline on
844        the end, a newline was missing in the output.
846    19. The default pcre_chartables.c file recognizes only ASCII characters (values
847        less than 128) in its various bitmaps. However, there is a facility for
848        generating tables according to the current locale when PCRE is compiled. It
849        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
850        characters, are recognized by isspace() and therefore were getting set in
851        these tables, and indeed these tables seem to approximate to ISO 8859. This
852        caused a problem in UTF-8 mode when pcre_study() was used to create a list
853        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
854        which of course cannot start UTF-8 characters. I have changed the code so
855        that only real ASCII characters (less than 128) and the correct starting
856        bytes for UTF-8 encodings are set for characters greater than 127 when in
857        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
858        altogether.)
860    20. Added the /T option to pcretest so as to be able to run tests with non-
861        standard character tables, thus making it possible to include the tests
862        used for 19 above in the standard set of tests.
864    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
865        reference to a subpattern the other side of a comment that contains an
866        opening parenthesis caused either an internal compiling error, or a
867        reference to the wrong subpattern.
870    Version 8.02 19-Mar-2010
871    ------------------------
873    1.  The Unicode data tables have been updated to Unicode 5.2.0.
875    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
876        configured.
878    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
879        original author of that file, following a query about its status.
881    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
882        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
884    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
885        quantifier applied to a forward-referencing subroutine call, could compile
886        incorrect code or give the error "internal error: previously-checked
887        referenced subpattern not found".
889    6.  Both MS Visual Studio and Symbian OS have problems with initializing
890        variables to point to external functions. For these systems, therefore,
891        pcre_malloc etc. are now initialized to local functions that call the
892        relevant global functions.
894    7.  There were two entries missing in the vectors called coptable and poptable
895        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
896        I've fixed the data, and added a kludgy way of testing at compile time that
897        the lengths are correct (equal to the number of opcodes).
899    8.  Following on from 7, I added a similar kludge to check the length of the
900        eint vector in pcreposix.c.
902    9.  Error texts for pcre_compile() are held as one long string to avoid too
903        much relocation at load time. To find a text, the string is searched,
904        counting zeros. There was no check for running off the end of the string,
905        which could happen if a new error number was added without updating the
906        string.
908    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
910    11. \K was not working if it appeared in an atomic group or in a group that
911        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
912        \K is "not well defined" if used in an assertion. PCRE now accepts it if
913        the assertion is positive, but not if it is negative.
915    12. Change 11 fortuitously reduced the size of the stack frame used in the
916        "match()" function of pcre_exec.c by one pointer. Forthcoming
917        implementation of support for (*MARK) will need an extra pointer on the
918        stack; I have reserved it now, so that the stack frame size does not
919        decrease.
921    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
922        item in branch that calls a recursion is a subroutine call - as in the
923        second branch in the above example - was incorrectly given the compile-
924        time error "recursive call could loop indefinitely" because pcre_compile()
925        was not correctly checking the subroutine for matching a non-empty string.
927    14. The checks for overrunning compiling workspace could trigger after an
928        overrun had occurred. This is a "should never occur" error, but it can be
929        triggered by pathological patterns such as hundreds of nested parentheses.
930        The checks now trigger 100 bytes before the end of the workspace.
932    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
935    Version 8.01 19-Jan-2010
936    ------------------------
938    1.  If a pattern contained a conditional subpattern with only one branch (in
939        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
940        computed the wrong minimum data length (which is of course zero for such
941        subpatterns). This could cause incorrect "no match" results.
943    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
944        the pattern is reset in the first branch, pcre_compile() failed with
945        "internal error: code overflow at offset...". This happened only when
946        the reset was to the original external option setting. (An optimization
947        abstracts leading options settings into an external setting, which was the
948        cause of this.)
950    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
951        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
952        assertion pattern did not match (meaning that the assertion was true), it
953        was incorrectly treated as false if the SKIP had been reached during the
954        matching. This also applied to assertions used as conditions.
956    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
957        assertion subpattern, including such a pattern used as a condition,
958        unpredictable results occurred, instead of the error return
961    5.  The C++ GlobalReplace function was not working like Perl for the special
962        situation when an empty string is matched. It now does the fancy magic
963        stuff that is necessary.
965    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
966        removed. (These were left over from very, very early versions of PCRE.)
968    7.  Some cosmetic changes to the code to make life easier when compiling it
969        as part of something else:
971        (a) Change DEBUG to PCRE_DEBUG.
973        (b) In pcre_compile(), rename the member of the "branch_chain" structure
974            called "current" as "current_branch", to prevent a collision with the
975            Linux macro when compiled as a kernel module.
977        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
978            prevent a collision with the Linux macro when compiled as a kernel
979            module.
981    8.  In pcre_compile() there are some checks for integer overflows that used to
982        cast potentially large values to (double). This has been changed to that
983        when building, a check for int64_t is made, and if it is found, it is used
984        instead, thus avoiding the use of floating point arithmetic. (There is no
985        other use of FP in PCRE.) If int64_t is not found, the fallback is to
986        double.
988    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
989        2005 (difference between two addresses compared to an unsigned value).
991    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
992        custom one, because of the following reported problem in Windows:
994          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
995              under Win32.
996          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
997              therefore missing the function definition.
998          - The compiler thus generates a "C" signature for the test function.
999          - The linker fails to find the "C" function.
1000          - PCRE fails to configure if asked to do so against libbz2.
1002    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
1003        messages were output:
1005          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
1006          rerunning libtoolize, to keep the correct libtool macros in-tree.
1007          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
1009        I have done both of these things.
1011    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
1012        most of the time, it *can* run out if it is given a pattern that contains a
1013        runaway infinite recursion. I updated the discussion in the pcrestack man
1014        page.
1016    13. Now that we have gone to the x.xx style of version numbers, the minor
1017        version may start with zero. Using 08 or 09 is a bad idea because users
1018        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
1019        interpreted as invalid octal numbers. I've updated the previous comment in
1020        configure.ac, and also added a check that gives an error if 08 or 09 are
1021        used.
1023    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1024        causing partial matching to fail when the end of the subject matched \W
1025        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1027    15. There were some discrepancies between the declarations in pcre_internal.h
1028        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1029        their definitions. The declarations used "const uschar *" and the
1030        definitions used USPTR. Even though USPTR is normally defined as "const
1031        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1032        reported that: "This difference in casting confuses some C++ compilers, for
1033        example, SunCC recognizes above declarations as different functions and
1034        generates broken code for hbpcre." I have changed the declarations to use
1035        USPTR.
1037    16. GNU libtool is named differently on some systems. The autogen.sh script now
1038        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1039        (FreeBSD).
1041    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1042        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1043        comment: "Figure out how to create a longlong from a string: strtoll and
1044        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1045        instance, but it only takes 2 args instead of 3!"
1047    18. A subtle bug concerned with back references has been fixed by a change of
1048        specification, with a corresponding code fix. A pattern such as
1049        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1050        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1051        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1052        same bug. Such groups have to be quantified to be useful, or contained
1053        inside another quantified group. (If there's no repetition, the reference
1054        can never match.) The problem arises because, having left the group and
1055        moved on to the rest of the pattern, a later failure that backtracks into
1056        the group uses the captured value from the final iteration of the group
1057        rather than the correct earlier one. I have fixed this in PCRE by forcing
1058        any group that contains a reference to itself to be an atomic group; that
1059        is, there cannot be any backtracking into it once it has completed. This is
1060        similar to recursive and subroutine calls.
1063    Version 8.00 19-Oct-09
1064  ----------------------  ----------------------
1066  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
1067      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
1068      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
1069      error.      error.
1071    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1072        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1073        in a Windows environment.
1075    3.  The pcregrep --count option prints the count for each file even when it is
1076        zero, as does GNU grep. However, pcregrep was also printing all files when
1077        --files-with-matches was added. Now, when both options are given, it prints
1078        counts only for those files that have at least one match. (GNU grep just
1079        prints the file name in this circumstance, but including the count seems
1080        more useful - otherwise, why use --count?) Also ensured that the
1081        combination -clh just lists non-zero counts, with no names.
1083    4.  The long form of the pcregrep -F option was incorrectly implemented as
1084        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1085        but it seems right to fix it, and I didn't think it was worth preserving
1086        the old behaviour.
1088    5.  The command line items --regex=pattern and --regexp=pattern were not
1089        recognized by pcregrep, which required --regex pattern or --regexp pattern
1090        (with a space rather than an '='). The man page documented the '=' forms,
1091        which are compatible with GNU grep; these now work.
1093    6.  No libpcreposix.pc file was created for pkg-config; there was just
1094        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1096    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1097        when UCP support is not needed, by modifying the Python script that
1098        generates it from Unicode data files. This should not matter if the module
1099        is correctly used as a library, but I received one complaint about 50K of
1100        unwanted data. My guess is that the person linked everything into his
1101        program rather than using a library. Anyway, it does no harm.
1103    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1104        was a minimum greater than 1 for a wide character in a possessive
1105        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1106        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1107        character. Chaos in the form of incorrect output or a compiling loop could
1108        result.
1110    9.  The restrictions on what a pattern can contain when partial matching is
1111        requested for pcre_exec() have been removed. All patterns can now be
1112        partially matched by this function. In addition, if there are at least two
1113        slots in the offset vector, the offset of the earliest inspected character
1114        for the match and the offset of the end of the subject are set in them when
1115        PCRE_ERROR_PARTIAL is returned.
1117    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1118        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1119        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1120        and may be more useful for multi-segment matching.
1122    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1123        used to be given if ever the end of the subject was reached; now it is
1124        given only if matching could not proceed because another character was
1125        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1126        string "Z", which now yields "no match" instead of "partial match". In the
1127        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1128        final character ended with (*FAIL).
1130    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1131        if the pattern had a "must contain" character that was already found in the
1132        earlier partial match, unless partial matching was again requested. For
1133        example, with the pattern /dog.(body)?/, the "must contain" character is
1134        "g". If the first part-match was for the string "dog", restarting with
1135        "sbody" failed. This bug has been fixed.
1137    13. The string returned by pcre_dfa_exec() after a partial match has been
1138        changed so that it starts at the first inspected character rather than the
1139        first character of the match. This makes a difference only if the pattern
1140        starts with a lookbehind assertion or \b or \B (\K is not supported by
1141        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1142        matching functions compatible, and I think it's the right thing to do.
1144    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1145        so that the demonstration program is easily available in environments where
1146        PCRE has not been installed from source.
1148    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1149        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1150        library.
1152    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1153        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1154        is not the first non-POSIX option to be added. Clearly some people find
1155        these options useful.
1157    17. If a caller to the POSIX matching function regexec() passes a non-zero
1158        value for nmatch with a NULL value for pmatch, the value of
1159        nmatch is forced to zero.
1161    18. RunGrepTest did not have a test for the availability of the -u option of
1162        the diff command, as RunTest does. It now checks in the same way as
1163        RunTest, and also checks for the -b option.
1165    19. If an odd number of negated classes containing just a single character
1166        interposed, within parentheses, between a forward reference to a named
1167        subpattern and the definition of the subpattern, compilation crashed with
1168        an internal error, complaining that it could not find the referenced
1169        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1170        [The bug was that it was starting one character too far in when skipping
1171        over the character class, thus treating the ] as data rather than
1172        terminating the class. This meant it could skip too much.]
1174    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1175        /g option in pcretest when the pattern contains \K, which makes it possible
1176        to have an empty string match not at the start, even when the pattern is
1177        anchored. Updated pcretest and pcredemo to use this option.
1179    21. If the maximum number of capturing subpatterns in a recursion was greater
1180        than the maximum at the outer level, the higher number was returned, but
1181        with unset values at the outer level. The correct (outer level) value is
1182        now given.
1184    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1185        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1186        make it do so. The string so far is captured, making this feature
1187        compatible with Perl.
1189    23. The tests have been re-organized, adding tests 11 and 12, to make it
1190        possible to check the Perl 5.10 features against Perl 5.10.
1192    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1193        pattern matches a fixed length string. PCRE did not allow this; now it
1194        does. Neither allows recursion.
1196    25. I finally figured out how to implement a request to provide the minimum
1197        length of subject string that was needed in order to match a given pattern.
1198        (It was back references and recursion that I had previously got hung up
1199        on.) This code has now been added to pcre_study(); it finds a lower bound
1200        to the length of subject needed. It is not necessarily the greatest lower
1201        bound, but using it to avoid searching strings that are too short does give
1202        some useful speed-ups. The value is available to calling programs via
1203        pcre_fullinfo().
1205    26. While implementing 25, I discovered to my embarrassment that pcretest had
1206        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1207        study optimizations had never been tested with that matching function.
1208        Oops. What is worse, even when it was passed study data, there was a bug in
1209        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1210        were also very few tests of studied patterns with pcre_dfa_exec().
1212    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1213        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1214        on the other side of the coin, they are no longer allowed to have different
1215        names, because these cannot be distinguished in PCRE, and this has caused
1216        confusion. (This is a difference from Perl.)
1218    28. When duplicate subpattern names are present (necessarily with different
1219        numbers, as required by 27 above), and a test is made by name in a
1220        conditional pattern, either for a subpattern having been matched, or for
1221        recursion in such a pattern, all the associated numbered subpatterns are
1222        tested, and the overall condition is true if the condition is true for any
1223        one of them. This is the way Perl works, and is also more like the way
1224        testing by number works.
1227  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
1228  ---------------------  ---------------------

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