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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.21
5    ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". This
60        is now checked, and causes "too many forward references" instead.
62    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
63        incorrectly expecting the subject to contain another "a" after the start.
65    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
66        in the match, the SKIP should be ignored. This was not happening; instead
67        the SKIP was being treated as NOMATCH. For patterns such as
68        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
69        tested.
71    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
72        now much more compatible with Perl, in particular in cases where the result
73        is a non-match for a non-anchored pattern. For example, if
74        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
75        "m", where previously it did not return a name. A side effect of this
76        change is that for partial matches, the last encountered mark name is
77        returned, as for non matches. A number of tests that were previously not
78        Perl-compatible have been moved into the Perl-compatible test files. The
79        refactoring has had the pleasing side effect of removing one argument from
80        the match() function, thus reducing its stack requirements.
83    Version 8.20 21-Oct-2011
84    ------------------------
86    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
87        a POSIX class. After further experiments with Perl, which convinced me that
88        Perl has bugs and confusions, a closing square bracket is no longer allowed
89        in a POSIX name. This bug also affected patterns with classes that started
90        with full stops.
92    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
93        captured substring, but while checking the failing first alternative,
94        substring 1 is temporarily captured. If the output vector supplied to
95        pcre_exec() was not big enough for this capture, the yield of the function
96        was still zero ("insufficient space for captured substrings"). This cannot
97        be totally fixed without adding another stack variable, which seems a lot
98        of expense for a edge case. However, I have improved the situation in cases
99        such as /(a)(b)x|abc/ matched against "abc", where the return code
100        indicates that fewer than the maximum number of slots in the ovector have
101        been set.
103    3.  Related to (2) above: when there are more back references in a pattern than
104        slots in the output vector, pcre_exec() uses temporary memory during
105        matching, and copies in the captures as far as possible afterwards. It was
106        using the entire output vector, but this conflicts with the specification
107        that only 2/3 is used for passing back captured substrings. Now it uses
108        only the first 2/3, for compatibility. This is, of course, another edge
109        case.
111    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
112        main code base, and can be used by building with --enable-jit. When this is
113        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
114        runtime --no-jit option is given.
116    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
117        ovector, the return from the function was zero, implying that there were
118        other matches that did not fit. The correct "exactly full" value is now
119        returned.
121    6.  If a subpattern that was called recursively or as a subroutine contained
122        (*PRUNE) or any other control that caused it to give a non-standard return,
123        invalid errors such as "Error -26 (nested recursion at the same subject
124        position)" or even infinite loops could occur.
126    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
127        computing the minimum length on reaching *ACCEPT, and so ended up with the
128        wrong value of 1 rather than 0. Further investigation indicates that
129        computing a minimum subject length in the presence of *ACCEPT is difficult
130        (think back references, subroutine calls), and so I have changed the code
131        so that no minimum is registered for a pattern that contains *ACCEPT.
133    8.  If (*THEN) was present in the first (true) branch of a conditional group,
134        it was not handled as intended. [But see 16 below.]
136    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
137        Sheri Pierce.
139    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
140        the first byte in a match must be "a".
142    11. Change 17 for 8.13 increased the recursion depth for patterns like
143        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
144        pattern contains any instances of (*THEN). If it does not, the old
145        optimizations are restored. It would be nice to do this on a per-group
146        basis, but at the moment that is not feasible.
148    12. In some environments, the output of pcretest -C is CRLF terminated. This
149        broke RunTest's code that checks for the link size. A single white space
150        character after the value is now allowed for.
152    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
153        For "fr", it uses the Windows-specific input and output files.
155    14. If (*THEN) appeared in a group that was called recursively or as a
156        subroutine, it did not work as intended. [But see next item.]
158    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
159        pattern fragments (but not containing any | characters). If A and B are
160        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
161        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
162        D. In other words, Perl considers parentheses that do not contain any |
163        characters to be part of a surrounding alternative, whereas PCRE was
164        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
165        differently. PCRE now behaves in the same way as Perl, except in the case
166        of subroutine/recursion calls such as (?1) which have in any case always
167        been different (but PCRE had them first :-).
169    16. Related to 15 above: Perl does not treat the | in a conditional group as
170        creating alternatives. Such a group is treated in the same way as an
171        ordinary group without any | characters when processing (*THEN). PCRE has
172        been changed to match Perl's behaviour.
174    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
175        RunGrepTest script failed.
177    18. Change 22 for version 13 caused atomic groups to use more stack. This is
178        inevitable for groups that contain captures, but it can lead to a lot of
179        stack use in large patterns. The old behaviour has been restored for atomic
180        groups that do not contain any capturing parentheses.
182    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
183        suppress the check for a minimum subject length at run time. (If it was
184        given to pcre_exec() or pcre_dfa_exec() it did work.)
186    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
187        fail to work when decoding hex characters in data strings in EBCDIC
188        environments.
190    21. It appears that in at least one Mac OS environment, the isxdigit() function
191        is implemented as a macro that evaluates to its argument more than once,
192        contravening the C 90 Standard (I haven't checked a later standard). There
193        was an instance in pcretest which caused it to go wrong when processing
194        \x{...} escapes in subject strings. The has been rewritten to avoid using
195        things like p++ in the argument of isxdigit().
198    Version 8.13 16-Aug-2011
199    ------------------------
201    1.  The Unicode data tables have been updated to Unicode 6.0.0.
203    2.  Two minor typos in pcre_internal.h have been fixed.
205    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
206        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
207        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
209    4.  There were a number of related bugs in the code for matching backrefences
210        caselessly in UTF-8 mode when codes for the characters concerned were
211        different numbers of bytes. For example, U+023A and U+2C65 are an upper
212        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
213        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
214        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
215        2-byte code at the end of the subject (it thought there wasn't enough data
216        left).
218    5.  Comprehensive information about what went wrong is now returned by
219        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
220        as the output vector has at least 2 elements. The offset of the start of
221        the failing character and a reason code are placed in the vector.
223    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
224        now returned is for the first byte of the failing character, instead of the
225        last byte inspected. This is an incompatible change, but I hope it is small
226        enough not to be a problem. It makes the returned offset consistent with
227        pcre_exec() and pcre_dfa_exec().
229    7.  pcretest now gives a text phrase as well as the error number when
230        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
231        failure, the offset and reason code are output.
233    8.  When \R was used with a maximizing quantifier it failed to skip backwards
234        over a \r\n pair if the subsequent match failed. Instead, it just skipped
235        back over a single character (\n). This seems wrong (because it treated the
236        two characters as a single entity when going forwards), conflicts with the
237        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
238        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
239        has been changed.
241    9.  Some internal refactoring has changed the processing so that the handling
242        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
243        time (the PCRE_DOTALL option was changed this way some time ago: version
244        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
245        which was always a bit of a fudge. It also means that there is one less
246        argument for the match() function, which reduces its stack requirements
247        slightly. This change also fixes an incompatibility with Perl: the pattern
248        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
250    10. More internal refactoring has drastically reduced the number of recursive
251        calls to match() for possessively repeated groups such as (abc)++ when
252        using pcre_exec().
254    11. While implementing 10, a number of bugs in the handling of groups were
255        discovered and fixed:
257        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
258        (a|)*(?1) gave a compile-time internal error.
259        ((a|)+)+  did not notice that the outer group could match an empty string.
260        (^a|^)+   was not marked as anchored.
261        (.*a|.*)+ was not marked as matching at start or after a newline.
263    12. Yet more internal refactoring has removed another argument from the match()
264        function. Special calls to this function are now indicated by setting a
265        value in a variable in the "match data" data block.
267    13. Be more explicit in pcre_study() instead of relying on "default" for
268        opcodes that mean there is no starting character; this means that when new
269        ones are added and accidentally left out of pcre_study(), testing should
270        pick them up.
272    14. The -s option of pcretest has been documented for ages as being an old
273        synonym of -m (show memory usage). I have changed it to mean "force study
274        for every regex", that is, assume /S for every regex. This is similar to -i
275        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
276        using it. It makes it easier to run collections of tests with and without
277        study enabled, and thereby test pcre_study() more easily. All the standard
278        tests are now run with and without -s (but some patterns can be marked as
279        "never study" - see 20 below).
281    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
282        restoration of the capturing data to the outer values was not happening
283        correctly.
285    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
286        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
287        pattern had matched an empty string, and so incorrectly returned a no
288        match.
290    17. There was optimizing code for the last branch of non-capturing parentheses,
291        and also for the obeyed branch of a conditional subexpression, which used
292        tail recursion to cut down on stack usage. Unfortunately, now that there is
293        the possibility of (*THEN) occurring in these branches, tail recursion is
294        no longer possible because the return has to be checked for (*THEN). These
295        two optimizations have therefore been removed. [But see 8.20/11 above.]
297    18. If a pattern containing \R was studied, it was assumed that \R always
298        matched two bytes, thus causing the minimum subject length to be
299        incorrectly computed because \R can also match just one byte.
301    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
302        was incorrectly computed.
304    20. If /S is present twice on a test pattern in pcretest input, it now
305        *disables* studying, thereby overriding the use of -s on the command line
306        (see 14 above). This is necessary for one or two tests to keep the output
307        identical in both cases.
309    21. When (*ACCEPT) was used in an assertion that matched an empty string and
310        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
312    22. When an atomic group that contained a capturing parenthesis was
313        successfully matched, but the branch in which it appeared failed, the
314        capturing was not being forgotten if a higher numbered group was later
315        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
316        group 1 to "a", when in fact it should be unset. This applied to multi-
317        branched capturing and non-capturing groups, repeated or not, and also to
318        positive assertions (capturing in negative assertions does not happen
319        in PCRE) and also to nested atomic groups.
321    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
322        subject after a captured substring, to make it easier to tell which of a
323        number of identical substrings has been captured.
325    24. The way atomic groups are processed by pcre_exec() has been changed so that
326        if they are repeated, backtracking one repetition now resets captured
327        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
328        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
329        "aaa". Previously, it would have been "a". As part of this code
330        refactoring, the way recursive calls are handled has also been changed.
332    25. If an assertion condition captured any substrings, they were not passed
333        back unless some other capturing happened later. For example, if
334        (?(?=(a))a) was matched against "a", no capturing was returned.
336    26. When studying a pattern that contained subroutine calls or assertions,
337        the code for finding the minimum length of a possible match was handling
338        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
339        group 1 called group 2 while simultaneously a separate group 2 called group
340        1). A stack overflow occurred in this case. I have fixed this by limiting
341        the recursion depth to 10.
343    27. Updated RunTest.bat in the distribution to the version supplied by Tom
344        Fortmann. This supports explicit test numbers on the command line, and has
345        argument validation and error reporting.
347    28. An instance of \X with an unlimited repeat could fail if at any point the
348        first character it looked at was a mark character.
350    29. Some minor code refactoring concerning Unicode properties and scripts
351        should reduce the stack requirement of match() slightly.
353    30. Added the '=' option to pcretest to check the setting of unused capturing
354        slots at the end of the pattern, which are documented as being -1, but are
355        not included in the return count.
357    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
358        compiled something random. Now it gives a compile-time error (as does
359        Perl).
361    32. A *MARK encountered during the processing of a positive assertion is now
362        recorded and passed back (compatible with Perl).
364    33. If --only-matching or --colour was set on a pcregrep call whose pattern
365        had alternative anchored branches, the search for a second match in a line
366        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
367        matched the line "0102" twice. The same bug affected patterns that started
368        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
369        twice.
371    34. Previously, PCRE did not allow quantification of assertions. However, Perl
372        does, and because of capturing effects, quantifying parenthesized
373        assertions may at times be useful. Quantifiers are now allowed for
374        parenthesized assertions.
376    35. A minor code tidy in pcre_compile() when checking options for \R usage.
378    36. \g was being checked for fancy things in a character class, when it should
379        just be a literal "g".
381    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
382        appearance of a nested POSIX class supersedes an apparent external class.
383        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
384        unescaped square brackets may also appear as part of class names. For
385        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
386        more like Perl. (But see 8.20/1 above.)
388    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
389        was because it thought it was \N{name}, which is not supported).
391    39. Add minix to OS list not supporting the -S option in pcretest.
393    40. PCRE tries to detect cases of infinite recursion at compile time, but it
394        cannot analyze patterns in sufficient detail to catch mutual recursions
395        such as ((?1))((?2)). There is now a runtime test that gives an error if a
396        subgroup is called recursively as a subpattern for a second time at the
397        same position in the subject string. In previous releases this might have
398        been caught by the recursion limit, or it might have run out of stack.
400    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
401        happen only once. PCRE was, however incorrectly giving a compile time error
402        "recursive call could loop indefinitely" because it cannot analyze the
403        pattern in sufficient detail. The compile time test no longer happens when
404        PCRE is compiling a conditional subpattern, but actual runaway loops are
405        now caught at runtime (see 40 above).
407    42. It seems that Perl allows any characters other than a closing parenthesis
408        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
409        has been changed to be the same.
411    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
412        as not to get warnings when autogen.sh is called. Also changed
413        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
415    44. To help people who use pcregrep to scan files containing exceedingly long
416        lines, the following changes have been made:
418        (a) The default value of the buffer size parameter has been increased from
419            8K to 20K. (The actual buffer used is three times this size.)
421        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
422            PCRE is built.
424        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
425            to be set at run time.
427        (d) Numerical values in pcregrep options can be followed by K or M, for
428            example --buffer-size=50K.
430        (e) If a line being scanned overflows pcregrep's buffer, an error is now
431            given and the return code is set to 2.
433    45. Add a pointer to the latest mark to the callout data block.
435    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
436        partial match of an empty string instead of no match. This was specific to
437        the use of ".".
439    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
440        complete match instead of a partial match. This bug was dependent on both
441        the PCRE_UTF8 and PCRE_DOTALL options being set.
443    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
444        starting byte set, because \b was not being ignored.
447    Version 8.12 15-Jan-2011
448    ------------------------
450    1.  Fixed some typos in the markup of the man pages, and wrote a script that
451        checks for such things as part of the documentation building process.
453    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
454        --match-limit and --recursion-limit options (added for 8.11). In
455        particular, this made one of the standard tests fail. (The integer value
456        went into the wrong half of a long int.)
458    3.  If the --colour option was given to pcregrep with -v (invert match), it
459        did strange things, either producing crazy output, or crashing. It should,
460        of course, ignore a request for colour when reporting lines that do not
461        match.
463    4.  Another pcregrep bug caused similar problems if --colour was specified with
464        -M (multiline) and the pattern match finished with a line ending.
466    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
467        matched in multiline mode, the following line was shown as part of the
468        match. This seems wrong, so I have changed it.
470    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
471        the check for further matches in the same line (so they could be coloured)
472        to overrun the end of the current line. If another match was found, it was
473        incorrectly shown (and then shown again when found in the next line).
475    7.  If pcregrep was compiled under Windows, there was a reference to the
476        function pcregrep_exit() before it was defined. I am assuming this was
477        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
478        reported by a user. I've moved the definition above the reference.
481    Version 8.11 10-Dec-2010
482    ------------------------
484    1.  (*THEN) was not working properly if there were untried alternatives prior
485        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
486        backtracked to try for "b" instead of moving to the next alternative branch
487        at the same level (in this case, to look for "c"). The Perl documentation
488        is clear that when (*THEN) is backtracked onto, it goes to the "next
489        alternative in the innermost enclosing group".
491    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
492        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
493        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
494        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
495        (*THEN).
497    3.  If \s appeared in a character class, it removed the VT character from
498        the class, even if it had been included by some previous item, for example
499        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
500        of \s, but is part of the POSIX "space" class.)
502    4.  A partial match never returns an empty string (because you can always
503        match an empty string at the end of the subject); however the checking for
504        an empty string was starting at the "start of match" point. This has been
505        changed to the "earliest inspected character" point, because the returned
506        data for a partial match starts at this character. This means that, for
507        example, /(?<=abc)def/ gives a partial match for the subject "abc"
508        (previously it gave "no match").
510    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
511        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
512        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
513        has an implication that the given string is incomplete (because a partial
514        match is preferred over a full match). For this reason, these items now
515        give a partial match in this situation. [Aside: previously, the one case
516        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
517        match rather than a full match, which was wrong by the old rules, but is
518        now correct.]
520    6.  There was a bug in the handling of #-introduced comments, recognized when
521        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
522        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
523        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
524        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
525        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
526        places in pcre_compile().
528    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
529        comments when looking ahead for named forward references to subpatterns,
530        the only newline sequence it recognized was NL. It now handles newlines
531        according to the set newline convention.
533    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
534        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
535        cater for a lack of strerror(). These oversights have been fixed.
537    9.  Added --match-limit and --recursion-limit to pcregrep.
539    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
541    11. When the -o option was used, pcregrep was setting a return code of 1, even
542        when matches were found, and --line-buffered was not being honoured.
544    12. Added an optional parentheses number to the -o and --only-matching options
545        of pcregrep.
547    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
548        can match an empty string. The code to do it in pcretest and pcredemo
549        needed fixing:
551        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
552            only one byte after an empty string match just before CRLF (this case
553            just got forgotten; "any" and "anycrlf" were OK).
555        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
556            mode when an empty string match preceded an ASCII character followed by
557            a non-ASCII character. (The code for advancing by one character rather
558            than one byte was nonsense.)
560        (c) The pcredemo.c sample program did not have any code at all to handle
561            the cases when CRLF is a valid newline sequence.
563    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
564        as a starting offset was within the subject string. There is now a new
565        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
566        negative or greater than the length of the string. In order to test this,
567        pcretest is extended to allow the setting of negative starting offsets.
569    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
570        starting offset points to the beginning of a UTF-8 character was
571        unnecessarily clumsy. I tidied it up.
573    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
574        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
576    17. Nobody had reported that the --include_dir option, which was added in
577        release 7.7 should have been called --include-dir (hyphen, not underscore)
578        for compatibility with GNU grep. I have changed it to --include-dir, but
579        left --include_dir as an undocumented synonym, and the same for
580        --exclude-dir, though that is not available in GNU grep, at least as of
581        release 2.5.4.
583    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
584        characters from a string of bytes) have been redefined so as not to use
585        loops, in order to improve performance in some environments. At the same
586        time, I abstracted some of the common code into auxiliary macros to save
587        repetition (this should not affect the compiled code).
589    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
590        compile-time error is now given if \c is not followed by an ASCII
591        character, that is, a byte less than 128. (In EBCDIC mode, the code is
592        different, and any byte value is allowed.)
594    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
595        START_OPTIMIZE option, which is now allowed at compile time - but just
596        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
597        to pcregrep and other applications that have no direct access to PCRE
598        options. The new /Y option in pcretest sets this option when calling
599        pcre_compile().
601    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
602        back references. Groups containing recursive back references were forced to
603        be atomic by that change, but in the case of named groups, the amount of
604        memory required was incorrectly computed, leading to "Failed: internal
605        error: code overflow". This has been fixed.
607    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
608        pcretest.c, to avoid build problems in some Borland environments.
611    Version 8.10 25-Jun-2010
612    ------------------------
614    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
615        THEN.
617    2.  (*ACCEPT) was not working when inside an atomic group.
619    3.  Inside a character class, \B is treated as a literal by default, but
620        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
621        causes the error). The code is unchanged, but I tidied the documentation.
623    4.  Inside a character class, PCRE always treated \R and \X as literals,
624        whereas Perl faults them if its -w option is set. I have changed PCRE so
625        that it faults them when PCRE_EXTRA is set.
627    5.  Added support for \N, which always matches any character other than
628        newline. (It is the same as "." when PCRE_DOTALL is not set.)
630    6.  When compiling pcregrep with newer versions of gcc which may have
631        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
632        declared with attribute warn_unused_result" were given. Just casting the
633        result to (void) does not stop the warnings; a more elaborate fudge is
634        needed. I've used a macro to implement this.
636    7.  Minor change to pcretest.c to avoid a compiler warning.
638    8.  Added four artifical Unicode properties to help with an option to make
639        \s etc use properties (see next item). The new properties are: Xan
640        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
642    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
643        use Unicode properties. (*UCP) at the start of a pattern can be used to set
644        this option. Modified pcretest to add /W to test this facility. Added
645        REG_UCP to make it available via the POSIX interface.
647    10. Added --line-buffered to pcregrep.
649    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
650        studied, and the match started with a letter with a code point greater than
651        127 whose first byte was different to the first byte of the other case of
652        the letter, the other case of this starting letter was not recognized
653        (#976).
655    12. If a pattern that was studied started with a repeated Unicode property
656        test, for example, \p{Nd}+, there was the theoretical possibility of
657        setting up an incorrect bitmap of starting bytes, but fortunately it could
658        not have actually happened in practice until change 8 above was made (it
659        added property types that matched character-matching opcodes).
661    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
662        possible starting bytes for non-anchored patterns.
664    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
665        \R, and also a number of cases that involve Unicode properties, both
666        explicit and implicit when PCRE_UCP is set.
668    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
669        input, it could crash or give wrong results if characters with values
670        greater than 0xc0 were present in the subject string. (Detail: it assumed
671        UTF-8 input when processing these items.)
673    16. Added a lot of (int) casts to avoid compiler warnings in systems where
674        size_t is 64-bit (#991).
676    17. Added a check for running out of memory when PCRE is compiled with
677        --disable-stack-for-recursion (#990).
679    18. If the last data line in a file for pcretest does not have a newline on
680        the end, a newline was missing in the output.
682    19. The default pcre_chartables.c file recognizes only ASCII characters (values
683        less than 128) in its various bitmaps. However, there is a facility for
684        generating tables according to the current locale when PCRE is compiled. It
685        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
686        characters, are recognized by isspace() and therefore were getting set in
687        these tables, and indeed these tables seem to approximate to ISO 8859. This
688        caused a problem in UTF-8 mode when pcre_study() was used to create a list
689        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
690        which of course cannot start UTF-8 characters. I have changed the code so
691        that only real ASCII characters (less than 128) and the correct starting
692        bytes for UTF-8 encodings are set for characters greater than 127 when in
693        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
694        altogether.)
696    20. Added the /T option to pcretest so as to be able to run tests with non-
697        standard character tables, thus making it possible to include the tests
698        used for 19 above in the standard set of tests.
700    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
701        reference to a subpattern the other side of a comment that contains an
702        opening parenthesis caused either an internal compiling error, or a
703        reference to the wrong subpattern.
706    Version 8.02 19-Mar-2010
707    ------------------------
709    1.  The Unicode data tables have been updated to Unicode 5.2.0.
711    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
712        configured.
714    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
715        original author of that file, following a query about its status.
717    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
718        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
720    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
721        quantifier applied to a forward-referencing subroutine call, could compile
722        incorrect code or give the error "internal error: previously-checked
723        referenced subpattern not found".
725    6.  Both MS Visual Studio and Symbian OS have problems with initializing
726        variables to point to external functions. For these systems, therefore,
727        pcre_malloc etc. are now initialized to local functions that call the
728        relevant global functions.
730    7.  There were two entries missing in the vectors called coptable and poptable
731        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
732        I've fixed the data, and added a kludgy way of testing at compile time that
733        the lengths are correct (equal to the number of opcodes).
735    8.  Following on from 7, I added a similar kludge to check the length of the
736        eint vector in pcreposix.c.
738    9.  Error texts for pcre_compile() are held as one long string to avoid too
739        much relocation at load time. To find a text, the string is searched,
740        counting zeros. There was no check for running off the end of the string,
741        which could happen if a new error number was added without updating the
742        string.
744    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
746    11. \K was not working if it appeared in an atomic group or in a group that
747        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
748        \K is "not well defined" if used in an assertion. PCRE now accepts it if
749        the assertion is positive, but not if it is negative.
751    12. Change 11 fortuitously reduced the size of the stack frame used in the
752        "match()" function of pcre_exec.c by one pointer. Forthcoming
753        implementation of support for (*MARK) will need an extra pointer on the
754        stack; I have reserved it now, so that the stack frame size does not
755        decrease.
757    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
758        item in branch that calls a recursion is a subroutine call - as in the
759        second branch in the above example - was incorrectly given the compile-
760        time error "recursive call could loop indefinitely" because pcre_compile()
761        was not correctly checking the subroutine for matching a non-empty string.
763    14. The checks for overrunning compiling workspace could trigger after an
764        overrun had occurred. This is a "should never occur" error, but it can be
765        triggered by pathological patterns such as hundreds of nested parentheses.
766        The checks now trigger 100 bytes before the end of the workspace.
768    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
771    Version 8.01 19-Jan-2010
772    ------------------------
774    1.  If a pattern contained a conditional subpattern with only one branch (in
775        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
776        computed the wrong minimum data length (which is of course zero for such
777        subpatterns). This could cause incorrect "no match" results.
779    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
780        the pattern is reset in the first branch, pcre_compile() failed with
781        "internal error: code overflow at offset...". This happened only when
782        the reset was to the original external option setting. (An optimization
783        abstracts leading options settings into an external setting, which was the
784        cause of this.)
786    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
787        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
788        assertion pattern did not match (meaning that the assertion was true), it
789        was incorrectly treated as false if the SKIP had been reached during the
790        matching. This also applied to assertions used as conditions.
792    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
793        assertion subpattern, including such a pattern used as a condition,
794        unpredictable results occurred, instead of the error return
797    5.  The C++ GlobalReplace function was not working like Perl for the special
798        situation when an empty string is matched. It now does the fancy magic
799        stuff that is necessary.
801    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
802        removed. (These were left over from very, very early versions of PCRE.)
804    7.  Some cosmetic changes to the code to make life easier when compiling it
805        as part of something else:
807        (a) Change DEBUG to PCRE_DEBUG.
809        (b) In pcre_compile(), rename the member of the "branch_chain" structure
810            called "current" as "current_branch", to prevent a collision with the
811            Linux macro when compiled as a kernel module.
813        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
814            prevent a collision with the Linux macro when compiled as a kernel
815            module.
817    8.  In pcre_compile() there are some checks for integer overflows that used to
818        cast potentially large values to (double). This has been changed to that
819        when building, a check for int64_t is made, and if it is found, it is used
820        instead, thus avoiding the use of floating point arithmetic. (There is no
821        other use of FP in PCRE.) If int64_t is not found, the fallback is to
822        double.
824    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
825        2005 (difference between two addresses compared to an unsigned value).
827    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
828        custom one, because of the following reported problem in Windows:
830          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
831              under Win32.
832          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
833              therefore missing the function definition.
834          - The compiler thus generates a "C" signature for the test function.
835          - The linker fails to find the "C" function.
836          - PCRE fails to configure if asked to do so against libbz2.
838    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
839        messages were output:
841          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
842          rerunning libtoolize, to keep the correct libtool macros in-tree.
843          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
845        I have done both of these things.
847    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
848        most of the time, it *can* run out if it is given a pattern that contains a
849        runaway infinite recursion. I updated the discussion in the pcrestack man
850        page.
852    13. Now that we have gone to the x.xx style of version numbers, the minor
853        version may start with zero. Using 08 or 09 is a bad idea because users
854        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
855        interpreted as invalid octal numbers. I've updated the previous comment in
856        configure.ac, and also added a check that gives an error if 08 or 09 are
857        used.
859    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
860        causing partial matching to fail when the end of the subject matched \W
861        in a UTF-8 pattern where \W was quantified with a minimum of 3.
863    15. There were some discrepancies between the declarations in pcre_internal.h
864        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
865        their definitions. The declarations used "const uschar *" and the
866        definitions used USPTR. Even though USPTR is normally defined as "const
867        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
868        reported that: "This difference in casting confuses some C++ compilers, for
869        example, SunCC recognizes above declarations as different functions and
870        generates broken code for hbpcre." I have changed the declarations to use
871        USPTR.
873    16. GNU libtool is named differently on some systems. The autogen.sh script now
874        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
875        (FreeBSD).
877    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
878        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
879        comment: "Figure out how to create a longlong from a string: strtoll and
880        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
881        instance, but it only takes 2 args instead of 3!"
883    18. A subtle bug concerned with back references has been fixed by a change of
884        specification, with a corresponding code fix. A pattern such as
885        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
886        refers, was giving matches when it shouldn't. For example, xa=xaaa would
887        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
888        same bug. Such groups have to be quantified to be useful, or contained
889        inside another quantified group. (If there's no repetition, the reference
890        can never match.) The problem arises because, having left the group and
891        moved on to the rest of the pattern, a later failure that backtracks into
892        the group uses the captured value from the final iteration of the group
893        rather than the correct earlier one. I have fixed this in PCRE by forcing
894        any group that contains a reference to itself to be an atomic group; that
895        is, there cannot be any backtracking into it once it has completed. This is
896        similar to recursive and subroutine calls.
899    Version 8.00 19-Oct-09
900    ----------------------
902    1.  The table for translating pcre_compile() error codes into POSIX error codes
903        was out-of-date, and there was no check on the pcre_compile() error code
904        being within the table. This could lead to an OK return being given in
905        error.
907    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
908        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
909        in a Windows environment.
911    3.  The pcregrep --count option prints the count for each file even when it is
912        zero, as does GNU grep. However, pcregrep was also printing all files when
913        --files-with-matches was added. Now, when both options are given, it prints
914        counts only for those files that have at least one match. (GNU grep just
915        prints the file name in this circumstance, but including the count seems
916        more useful - otherwise, why use --count?) Also ensured that the
917        combination -clh just lists non-zero counts, with no names.
919    4.  The long form of the pcregrep -F option was incorrectly implemented as
920        --fixed_strings instead of --fixed-strings. This is an incompatible change,
921        but it seems right to fix it, and I didn't think it was worth preserving
922        the old behaviour.
924    5.  The command line items --regex=pattern and --regexp=pattern were not
925        recognized by pcregrep, which required --regex pattern or --regexp pattern
926        (with a space rather than an '='). The man page documented the '=' forms,
927        which are compatible with GNU grep; these now work.
929    6.  No libpcreposix.pc file was created for pkg-config; there was just
930        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
932    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
933        when UCP support is not needed, by modifying the Python script that
934        generates it from Unicode data files. This should not matter if the module
935        is correctly used as a library, but I received one complaint about 50K of
936        unwanted data. My guess is that the person linked everything into his
937        program rather than using a library. Anyway, it does no harm.
939    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
940        was a minimum greater than 1 for a wide character in a possessive
941        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
942        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
943        character. Chaos in the form of incorrect output or a compiling loop could
944        result.
946    9.  The restrictions on what a pattern can contain when partial matching is
947        requested for pcre_exec() have been removed. All patterns can now be
948        partially matched by this function. In addition, if there are at least two
949        slots in the offset vector, the offset of the earliest inspected character
950        for the match and the offset of the end of the subject are set in them when
951        PCRE_ERROR_PARTIAL is returned.
953    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
954        synonymous with PCRE_PARTIAL, for backwards compatibility, and
955        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
956        and may be more useful for multi-segment matching.
958    11. Partial matching with pcre_exec() is now more intuitive. A partial match
959        used to be given if ever the end of the subject was reached; now it is
960        given only if matching could not proceed because another character was
961        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
962        string "Z", which now yields "no match" instead of "partial match". In the
963        case of pcre_dfa_exec(), "no match" is given if every matching path for the
964        final character ended with (*FAIL).
966    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
967        if the pattern had a "must contain" character that was already found in the
968        earlier partial match, unless partial matching was again requested. For
969        example, with the pattern /dog.(body)?/, the "must contain" character is
970        "g". If the first part-match was for the string "dog", restarting with
971        "sbody" failed. This bug has been fixed.
973    13. The string returned by pcre_dfa_exec() after a partial match has been
974        changed so that it starts at the first inspected character rather than the
975        first character of the match. This makes a difference only if the pattern
976        starts with a lookbehind assertion or \b or \B (\K is not supported by
977        pcre_dfa_exec()). It's an incompatible change, but it makes the two
978        matching functions compatible, and I think it's the right thing to do.
980    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
981        so that the demonstration program is easily available in environments where
982        PCRE has not been installed from source.
984    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
985        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
986        library.
988    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
989        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
990        is not the first non-POSIX option to be added. Clearly some people find
991        these options useful.
993    17. If a caller to the POSIX matching function regexec() passes a non-zero
994        value for nmatch with a NULL value for pmatch, the value of
995        nmatch is forced to zero.
997    18. RunGrepTest did not have a test for the availability of the -u option of
998        the diff command, as RunTest does. It now checks in the same way as
999        RunTest, and also checks for the -b option.
1001    19. If an odd number of negated classes containing just a single character
1002        interposed, within parentheses, between a forward reference to a named
1003        subpattern and the definition of the subpattern, compilation crashed with
1004        an internal error, complaining that it could not find the referenced
1005        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1006        [The bug was that it was starting one character too far in when skipping
1007        over the character class, thus treating the ] as data rather than
1008        terminating the class. This meant it could skip too much.]
1010    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1011        /g option in pcretest when the pattern contains \K, which makes it possible
1012        to have an empty string match not at the start, even when the pattern is
1013        anchored. Updated pcretest and pcredemo to use this option.
1015    21. If the maximum number of capturing subpatterns in a recursion was greater
1016        than the maximum at the outer level, the higher number was returned, but
1017        with unset values at the outer level. The correct (outer level) value is
1018        now given.
1020    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1021        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1022        make it do so. The string so far is captured, making this feature
1023        compatible with Perl.
1025    23. The tests have been re-organized, adding tests 11 and 12, to make it
1026        possible to check the Perl 5.10 features against Perl 5.10.
1028    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1029        pattern matches a fixed length string. PCRE did not allow this; now it
1030        does. Neither allows recursion.
1032    25. I finally figured out how to implement a request to provide the minimum
1033        length of subject string that was needed in order to match a given pattern.
1034        (It was back references and recursion that I had previously got hung up
1035        on.) This code has now been added to pcre_study(); it finds a lower bound
1036        to the length of subject needed. It is not necessarily the greatest lower
1037        bound, but using it to avoid searching strings that are too short does give
1038        some useful speed-ups. The value is available to calling programs via
1039        pcre_fullinfo().
1041    26. While implementing 25, I discovered to my embarrassment that pcretest had
1042        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1043        study optimizations had never been tested with that matching function.
1044        Oops. What is worse, even when it was passed study data, there was a bug in
1045        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1046        were also very few tests of studied patterns with pcre_dfa_exec().
1048    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1049        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1050        on the other side of the coin, they are no longer allowed to have different
1051        names, because these cannot be distinguished in PCRE, and this has caused
1052        confusion. (This is a difference from Perl.)
1054    28. When duplicate subpattern names are present (necessarily with different
1055        numbers, as required by 27 above), and a test is made by name in a
1056        conditional pattern, either for a subpattern having been matched, or for
1057        recursion in such a pattern, all the associated numbered subpatterns are
1058        tested, and the overall condition is true if the condition is true for any
1059        one of them. This is the way Perl works, and is also more like the way
1060        testing by number works.
1063    Version 7.9 11-Apr-09
1064    ---------------------
1066    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1067        (pcretest), all targets were linked against these libraries. This included
1068        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1069        libraries. This caused unwanted dependencies to be created. This problem
1070        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1071        pcretest is linked with readline.
1073    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1074        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1075        moved outside it again, because FALSE and TRUE are already defined in AIX,
1076        but BOOL is not.
1078    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1079        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1081    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1082        hyphens) following file names and line numbers when outputting matching
1083        lines. This is not true; no spaces are inserted. I have also clarified the
1084        wording for the --colour (or --color) option.
1086    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1087        was not coloured; this is different to GNU grep, so I have changed it to be
1088        the same.
1090    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1091        each matching line was coloured. Now it goes on to look for further matches
1092        of any of the test patterns, which is the same behaviour as GNU grep.
1094    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1095        doesn't make sense to accept an empty string match in pcregrep, so I have
1096        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1097        seems to be how GNU grep behaves.
1099    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1100        start or after a newline", because the conditional assertion was not being
1101        correctly handled. The rule now is that both the assertion and what follows
1102        in the first alternative must satisfy the test.
1104    9.  If auto-callout was enabled in a pattern with a conditional group whose
1105        condition was an assertion, PCRE could crash during matching, both with
1106        pcre_exec() and pcre_dfa_exec().
1108    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1109        used for matching.
1111    11. Unicode property support in character classes was not working for
1112        characters (bytes) greater than 127 when not in UTF-8 mode.
1114    12. Added the -M command line option to pcretest.
1116    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1118    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1120    16. Added comments and documentation about mis-use of no_arg in the C++
1121        wrapper.
1123    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1124        from Martin Jerabek that uses macro names for all relevant character and
1125        string constants.
1127    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1128        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1129        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1130        these, but not everybody uses configure.
1132    19. A conditional group that had only one branch was not being correctly
1133        recognized as an item that could match an empty string. This meant that an
1134        enclosing group might also not be so recognized, causing infinite looping
1135        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1136        with the subject "ab", where knowledge that the repeated group can match
1137        nothing is needed in order to break the loop.
1139    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1140        exec(), but without supplying a callout function, matching went wrong.
1142    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1143        leak if the size of the offset vector was greater than 30. When the vector
1144        is smaller, the saved offsets during recursion go onto a local stack
1145        vector, but for larger vectors malloc() is used. It was failing to free
1146        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1147        error, in fact).
1149    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1150        heapframe that is used only when UTF-8 support is enabled. This caused no
1151        problem, but was untidy.
1153    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1154        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1155        included within another project.
1157    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1158        slightly modified by me:
1160          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1161              not building pcregrep.
1163          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1164              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1166    25. Forward references, both numeric and by name, in patterns that made use of
1167        duplicate group numbers, could behave incorrectly or give incorrect errors,
1168        because when scanning forward to find the reference group, PCRE was not
1169        taking into account the duplicate group numbers. A pattern such as
1170        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1172    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1173        the feature of a custom pointer more persuasive (as requested by a user).
1175    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1176        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1177        pre-defined.
1179    28. Added support for (*UTF8) at the start of a pattern.
1181    29. Arrange for flags added by the "release type" setting in CMake to be shown
1182        in the configuration summary.
1185    Version 7.8 05-Sep-08
1186    ---------------------
1188    1.  Replaced UCP searching code with optimized version as implemented for Ad
1189        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1190        stage table and inline lookup instead of a function, giving speed ups of 2
1191        to 5 times on some simple patterns that I tested. Permission was given to
1192        distribute the MultiStage2.py script that generates the tables (it's not in
1193        the tarball, but is in the Subversion repository).
1195    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1196        scripts.
1198    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1199        a group with a zero qualifier. The result of the study could be incorrect,
1200        or the function might crash, depending on the pattern.
1202    4.  Caseless matching was not working for non-ASCII characters in back
1203        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1204        It now works when Unicode Property Support is available.
1206    5.  In pcretest, an escape such as \x{de} in the data was always generating
1207        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1208        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1209        truncation.
1211    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1213    7.  Added two (int) casts to pcregrep when printing the difference of two
1214        pointers, in case they are 64-bit values.
1216    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1217        test 2 if it fails.
1219    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1220        and a #define of that name to empty if it is not externally set. This is to
1221        allow users of MSVC to set it if necessary.
1223    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1224        the convenience functions in the pcre_get.c source file.
1226    11. An option change at the start of a pattern that had top-level alternatives
1227        could cause overwriting and/or a crash. This command provoked a crash in
1228        some environments:
1230          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1232        This potential security problem was recorded as CVE-2008-2371.
1234    12. For a pattern where the match had to start at the beginning or immediately
1235        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1236        pcre_dfa_exec() could read past the end of the passed subject if there was
1237        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1238        pcretest so that it places the subject at the end of its malloc-ed buffer.
1240    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1241        exec() might read past the end of the data buffer in UTF-8 mode.
1243    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1244        the data contained the byte 0x85 as part of a UTF-8 character within its
1245        first line. This applied both to normal and DFA matching.
1247    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1248        /^[^d]*?$/8 failed to match "abc".
1250    16. Added a missing copyright notice to pcrecpp_internal.h.
1252    17. Make it more clear in the documentation that values returned from
1253        pcre_exec() in ovector are byte offsets, not character counts.
1255    18. Tidied a few places to stop certain compilers from issuing warnings.
1257    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1258        supplied by Stefan Weber. I made a further small update for 7.8 because
1259        there is a change of source arrangements: the pcre_searchfuncs.c module is
1260        replaced by pcre_ucd.c.
1263    Version 7.7 07-May-08
1264    ---------------------
1266    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1267        a string to a long long, pretend we don't even have a long long." This is
1268        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1270    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1271        pre-7.6 versions, which defined a global no_arg variable instead of putting
1272        it in the RE class. (See also #8 below.)
1274    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1275        Lopes.
1277    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1279        (1) The include/exclude patterns were being applied to the whole pathnames
1280            of files, instead of just to the final components.
1282        (2) If there was more than one level of directory, the subdirectories were
1283            skipped unless they satisfied the include/exclude conditions. This is
1284            inconsistent with GNU grep (and could even be seen as contrary to the
1285            pcregrep specification - which I improved to make it absolutely clear).
1286            The action now is always to scan all levels of directory, and just
1287            apply the include/exclude patterns to regular files.
1289    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1290        --exclude_dir in the tests to avoid scanning .svn directories.
1292    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1293        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1294        doesn't support NULs in patterns.
1296    7.  Added some missing "const"s to declarations of static tables in
1297        pcre_compile.c and pcre_dfa_exec.c.
1299    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1300        caused by fix #2  above. (Subsequently also a second patch to fix the
1301        first patch. And a third patch - this was a messy problem.)
1303    9.  Applied Craig's patch to remove the use of push_back().
1305    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1306        matching function regexec().
1308    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1309        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1310        references. PCRE supports relative numbers with this syntax (I don't think
1311        Oniguruma does).
1313    12. Previously, a group with a zero repeat such as (...){0} was completely
1314        omitted from the compiled regex. However, this means that if the group
1315        was called as a subroutine from elsewhere in the pattern, things went wrong
1316        (an internal error was given). Such groups are now left in the compiled
1317        pattern, with a new opcode that causes them to be skipped at execution
1318        time.
1320    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1321        to the way PCRE behaves:
1323        (a) A lone ] character is dis-allowed (Perl treats it as data).
1325        (b) A back reference to an unmatched subpattern matches an empty string
1326            (Perl fails the current match path).
1328        (c) A data ] in a character class must be notated as \] because if the
1329            first data character in a class is ], it defines an empty class. (In
1330            Perl it is not possible to have an empty class.) The empty class []
1331            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1332            The negative empty class [^] matches any one character, independently
1333            of the DOTALL setting.
1335    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1336        non-existent subpattern following a character class starting with ']' and
1337        containing () gave an internal compiling error instead of "reference to
1338        non-existent subpattern". Fortunately, when the pattern did exist, the
1339        compiled code was correct. (When scanning forwards to check for the
1340        existencd of the subpattern, it was treating the data ']' as terminating
1341        the class, so got the count wrong. When actually compiling, the reference
1342        was subsequently set up correctly.)
1344    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1345        it was being rejected as not supported by pcre_dfa_exec(), even though
1346        other assertions are supported. I have made pcre_dfa_exec() support
1347        (*FAIL).
1349    16. The implementation of 13c above involved the invention of a new opcode,
1350        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1351        cannot be changed at match time, I realized I could make a small
1352        improvement to matching performance by compiling OP_ALLANY instead of
1353        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1354        on the OP_ANY path.
1356    17. Compiling pcretest on Windows with readline support failed without the
1357        following two fixes: (1) Make the unistd.h include conditional on
1358        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1360    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1361        ncurses library to be included for pcretest when ReadLine support is
1362        requested, but also to allow for it to be overridden. This patch came from
1363        Daniel Bergström.
1365    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1366        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1367        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1368        spotting this.
1371    Version 7.6 28-Jan-08
1372    ---------------------
1374    1.  A character class containing a very large number of characters with
1375        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1376        overflow.
1378    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1379        HAVE_LONG_LONG is not defined.
1381    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1382        bring them up to date and include new features. This patch includes:
1384        - Fixed PH's badly added libz and libbz2 support.
1385        - Fixed a problem with static linking.
1386        - Added pcredemo. [But later removed - see 7 below.]
1387        - Fixed dftables problem and added an option.
1388        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1389            HAVE_LONG_LONG.
1390        - Added readline support for pcretest.
1391        - Added an listing of the option settings after cmake has run.
1393    4.  A user submitted a patch to Makefile that makes it easy to create
1394        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1395        Makefile.am that cause it to include this special target, without
1396        affecting anything else. Note that the same mingw target plus all
1397        the other distribution libraries and programs are now supported
1398        when configuring with CMake (see 6 below) instead of with
1399        Configure/Make.
1401    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1402        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1403        exported in the Windows port". It has not yet been confirmed that the patch
1404        solves the problem, but it does no harm.
1406    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1407        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1408        with CMake, and also correct the comment about stack recursion.
1410    7.  Remove the automatic building of pcredemo from the ./configure system and
1411        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1412        of a program that users should build themselves after PCRE is installed, so
1413        building it automatically is not really right. What is more, it gave
1414        trouble in some build environments.
1416    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1419    Version 7.5 10-Jan-08
1420    ---------------------
1422    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1423        values in parens when parsing an RE using the C++ wrapper."
1425    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1426        Characters greater than 255 were excluded from the class instead of being
1427        included.
1429    3.  The same bug as (2) above applied to negated POSIX classes such as
1430        [:^space:].
1432    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1433        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1434        I have changed it.
1436    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1437        first named subpattern) and a construct such as (?&a) would reference the
1438        first named subpattern whose name started with "a" (in other words, the
1439        length check was missing). Both these problems are fixed. "Subpattern name
1440        expected" is now given for (?&) (a zero-length name), and this patch also
1441        makes it give the same error for \k'' (previously it complained that that
1442        was a reference to a non-existent subpattern).
1444    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1445        this is right because (?- can be followed by option settings as well as by
1446        digits. I have, however, made the messages clearer.
1448    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1449        than the number used in the conditional) now cause a compile-time error.
1450        This is actually not compatible with Perl, which accepts such patterns, but
1451        treats the conditional as always being FALSE (as PCRE used to), but it
1452        seems to me that giving a diagnostic is better.
1454    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1455        and messages.
1457    9.  Fix two occurrences of "backslash" in comments that should have been
1458        "backspace".
1460    10. Remove two redundant lines of code that can never be obeyed (their function
1461        was moved elsewhere).
1463    11. The program that makes PCRE's Unicode character property table had a bug
1464        which caused it to generate incorrect table entries for sequences of
1465        characters that have the same character type, but are in different scripts.
1466        It amalgamated them into a single range, with the script of the first of
1467        them. In other words, some characters were in the wrong script. There were
1468        thirteen such cases, affecting characters in the following ranges:
1470          U+002b0 - U+002c1
1471          U+0060c - U+0060d
1472          U+0061e - U+00612
1473          U+0064b - U+0065e
1474          U+0074d - U+0076d
1475          U+01800 - U+01805
1476          U+01d00 - U+01d77
1477          U+01d9b - U+01dbf
1478          U+0200b - U+0200f
1479          U+030fc - U+030fe
1480          U+03260 - U+0327f
1481          U+0fb46 - U+0fbb1
1482          U+10450 - U+1049d
1484    12. The -o option (show only the matching part of a line) for pcregrep was not
1485        compatible with GNU grep in that, if there was more than one match in a
1486        line, it showed only the first of them. It now behaves in the same way as
1487        GNU grep.
1489    13. If the -o and -v options were combined for pcregrep, it printed a blank
1490        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1491        does the same. The return code can be used to tell if there were any
1492        non-matching lines.
1494    14. Added --file-offsets and --line-offsets to pcregrep.
1496    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1497        infinitely looping recursion. The bug was that positive lookaheads were not
1498        being skipped when checking for a possible empty match (negative lookaheads
1499        and both kinds of lookbehind were skipped).
1501    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1502        inclusion of <windows.h> to before rather than after the definition of
1503        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1505    17. Specifying a possessive quantifier with a specific limit for a Unicode
1506        character property caused pcre_compile() to compile bad code, which led at
1507        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1508        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1509        caused the error; without that there was no problem.
1511    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1513    19. Added --enable-pcretest-libreadline.
1515    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1516        RE::GlobalReplace(). As a result, the number of replacements returned was
1517        double what it should be. I removed one of the increments, but Craig sent a
1518        later patch that removed the other one (the right fix) and added unit tests
1519        that check the return values (which was not done before).
1521    21. Several CMake things:
1523        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1524            the names libpcre and libpcreposix, not just pcre and pcreposix.
1526        (2) The above change means that pcretest and pcregrep are now correctly
1527            linked with the newly-built libraries, not previously installed ones.
1531    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1532        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1533        UTF-8 newline character). The key issue is that the pattern starts .*;
1534        this means that the match must be either at the beginning, or after a
1535        newline. The bug was in the code for advancing after a failed match and
1536        checking that the new position followed a newline. It was not taking
1537        account of UTF-8 characters correctly.
1539    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1540        character classes. PCRE was not treating the sequence [:...:] as a
1541        character class unless the ... were all letters. Perl, however, seems to
1542        allow any characters between [: and :], though of course it rejects as
1543        unknown any "names" that contain non-letters, because all the known class
1544        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1545        for example, whereas PCRE did not - it did not recognize a POSIX character
1546        class. This seemed a bit dangerous, so the code has been changed to be
1547        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1548        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1549        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1550        Perl does, and where it didn't before.
1552    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1553        Windows environments %n is disabled by default.
1556    Version 7.4 21-Sep-07
1557    ---------------------
1559    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1560        means that a class such as [\s] counted as "explicit reference to CR or
1561        LF". That isn't really right - the whole point of the change was to try to
1562        help when there was an actual mention of one of the two characters. So now
1563        the change happens only if \r or \n (or a literal CR or LF) character is
1564        encountered.
1566    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1567        of both had grown to the point where there were only 3 bits left.
1568        Fortunately, there was spare space in the data structure, and so I have
1569        moved the internal flags into a new 16-bit field to free up more option
1570        bits.
1572    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1573        but did not set the internal JCHANGED flag - either of these is enough to
1574        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1575        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1576        start sets both bits.
1578    4.  Added options (at build time, compile time, exec time) to change \R from
1579        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1581    5.  doc/pcresyntax.html was missing from the distribution.
1583    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1584        compatibility, even though it is no longer used.
1586    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1587        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1588        windows.h file is present (where different names are used). [This was
1589        reversed later after testing - see 16 below.]
1591    8.  Changed all #include <config.h> to #include "config.h". There were also
1592        some further <pcre.h> cases that I changed to "pcre.h".
1594    9.  When pcregrep was used with the --colour option, it missed the line ending
1595        sequence off the lines that it output.
1597    10. It was pointed out to me that arrays of string pointers cause lots of
1598        relocations when a shared library is dynamically loaded. A technique of
1599        using a single long string with a table of offsets can drastically reduce
1600        these. I have refactored PCRE in four places to do this. The result is
1601        dramatic:
1603          Originally:                          290
1604          After changing UCP table:            187
1605          After changing error message table:   43
1606          After changing table of "verbs"       36
1607          After changing table of Posix names   22
1609        Thanks to the folks working on Gregex for glib for this insight.
1611    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1612        unicode-properties was also set.
1614    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1616    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1617        checked only for CRLF.
1619    14. Added casts to pcretest.c to avoid compiler warnings.
1621    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1623    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1624        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1625        entirely. This removes changes made in 7 above.
1627    17. The CMake files have been updated, and there is now more information about
1628        building with CMake in the NON-UNIX-USE document.
1631    Version 7.3 28-Aug-07
1632    ---------------------
1634     1. In the rejigging of the build system that eventually resulted in 7.1, the
1635        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1636        brackets there is not right, since it causes compilers to look for an
1637        installed pcre.h, not the version that is in the source that is being
1638        compiled (which of course may be different). I have changed it back to:
1640          #include "pcre.h"
1642        I have a vague recollection that the change was concerned with compiling in
1643        different directories, but in the new build system, that is taken care of
1644        by the VPATH setting the Makefile.
1646     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1647        when the subject happened to end in the byte 0x85 (e.g. if the last
1648        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1649        characters but of course it shouldn't be taken as a newline when it is part
1650        of another character. The bug was that, for an unlimited repeat of . in
1651        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1652        characters when looking for a newline.
1654     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1656     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1657        in debug output.
1659     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1660        long printing in the pcrecpp unittest when running under MinGW.
1662     6. ESC_K was left out of the EBCDIC table.
1664     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1665        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1666        limit also applies to "virtual nesting" when a pattern is recursive, and in
1667        this case 1000 isn't so big. I have been able to remove this limit at the
1668        expense of backing off one optimization in certain circumstances. Normally,
1669        when pcre_exec() would call its internal match() function recursively and
1670        immediately return the result unconditionally, it uses a "tail recursion"
1671        feature to save stack. However, when a subpattern that can match an empty
1672        string has an unlimited repetition quantifier, it no longer makes this
1673        optimization. That gives it a stack frame in which to save the data for
1674        checking that an empty string has been matched. Previously this was taken
1675        from the 1000-entry workspace that had been reserved. So now there is no
1676        explicit limit, but more stack is used.
1678     8. Applied Daniel's patches to solve problems with the import/export magic
1679        syntax that is required for Windows, and which was going wrong for the
1680        pcreposix and pcrecpp parts of the library. These were overlooked when this
1681        problem was solved for the main library.
1683     9. There were some crude static tests to avoid integer overflow when computing
1684        the size of patterns that contain repeated groups with explicit upper
1685        limits. As the maximum quantifier is 65535, the maximum group length was
1686        set at 30,000 so that the product of these two numbers did not overflow a
1687        32-bit integer. However, it turns out that people want to use groups that
1688        are longer than 30,000 bytes (though not repeat them that many times).
1689        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1690        made it possible to implement the integer overflow checks in a much more
1691        dynamic way, which I have now done. The artificial limitation on group
1692        length has been removed - we now have only the limit on the total length of
1693        the compiled pattern, which depends on the LINK_SIZE setting.
1695    10. Fixed a bug in the documentation for get/copy named substring when
1696        duplicate names are permitted. If none of the named substrings are set, the
1697        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1698        empty string.
1700    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1701        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1702        because the ] is interpreted as the first data character and the
1703        terminating ] is not found. PCRE has been made compatible with Perl in this
1704        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1705        cause memory overwriting.
1707    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1708        string has been matched (to stop an infinite loop). It was not recognizing
1709        a conditional subpattern that could match an empty string if that
1710        subpattern was within another subpattern. For example, it looped when
1711        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1712        condition was not nested. This bug has been fixed.
1714    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1715        past the start of the subject in the presence of bytes with the top bit
1716        set, for example "\x8aBCD".
1718    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1719        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1721    14. Optimized (?!) to (*FAIL).
1723    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1724        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1725        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1726        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1727        does: it's just the validity check that is more restrictive.
1729    16. Inserted checks for integer overflows during escape sequence (backslash)
1730        processing, and also fixed erroneous offset values for syntax errors during
1731        backslash processing.
1733    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1734        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1736    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1737        caused an overrun.
1739    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1740        something other than just ASCII characters) inside a group that had an
1741        unlimited repeat caused a loop at compile time (while checking to see
1742        whether the group could match an empty string).
1744    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1745        [\P{Any}] did so. (Error in the code for printing property names.)
1747    21. An orphan \E inside a character class could cause a crash.
1749    22. A repeated capturing bracket such as (A)? could cause a wild memory
1750        reference during compilation.
1752    23. There are several functions in pcre_compile() that scan along a compiled
1753        expression for various reasons (e.g. to see if it's fixed length for look
1754        behind). There were bugs in these functions when a repeated \p or \P was
1755        present in the pattern. These operators have additional parameters compared
1756        with \d, etc, and these were not being taken into account when moving along
1757        the compiled data. Specifically:
1759        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1760            length.
1762        (b) An item such as \pL+ within a repeated group could cause crashes or
1763            loops.
1765        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1766            "reference to non-existent subpattern" error.
1768        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1770    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1771        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1773    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1775    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1776        character were causing crashes (broken optimization).
1778    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1779        \p or \P) caused a compile-time loop.
1781    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1782        break. For example, the unstudied pattern [\r\n]A does not match the string
1783        "\r\nA" because change 7.0/46 below moves the current point on by two
1784        characters after failing to match at the start. However, the pattern \nA
1785        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1786        the same is true. There doesn't seem any very clean way out of this, but
1787        what I have chosen to do makes the common cases work: PCRE now takes note
1788        of whether there can be an explicit match for \r or \n anywhere in the
1789        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1790        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1791        pattern has explicit CR or LF references.
1793    29. Added (*CR) etc for changing newline setting at start of pattern.
1796    Version 7.2 19-Jun-07
1797    ---------------------
1799     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1800        which is apparently normally available under Windows.
1802     2. Re-jig the pcregrep tests with different newline settings in an attempt
1803        to make them independent of the local environment's newline setting.
1805     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1807     4. Some of the "internals" tests were previously cut out when the link size
1808        was not 2, because the output contained actual offsets. The recent new
1809        "Z" feature of pcretest means that these can be cut out, making the tests
1810        usable with all link sizes.
1812     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1813        stack recursion. This gives a massive performance boost under BSD, but just
1814        a small improvement under Linux. However, it saves one field in the frame
1815        in all cases.
1817     6. Added more features from the forthcoming Perl 5.10:
1819        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1820            recursion call. It refers to the nth most recently opened parentheses.
1822        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1823            to be opened parentheses.
1825        (c) Conditions that refer to capturing parentheses can be specified
1826            relatively, for example, (?(-2)... or (?(+3)...
1828        (d) \K resets the start of the current match so that everything before
1829            is not part of it.
1831        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1833        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1834            reference syntax.
1836        (g) (?| introduces a group in which the numbering of parentheses in each
1837            alternative starts with the same number.
1839        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1841     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1844     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1845        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1846        for detecting groups that can match an empty string.
1848     9. A pattern with a very large number of alternatives (more than several
1849        hundred) was running out of internal workspace during the pre-compile
1850        phase, where pcre_compile() figures out how much memory will be needed. A
1851        bit of new cunning has reduced the workspace needed for groups with
1852        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1853        workspace instead of running out of the 4096 that are available.
1855    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1857    11. Applied patch from Google to remove an optimization that didn't quite work.
1858        The report of the bug said:
1860          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1861          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1862          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1864    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1865        it matched the wrong number of bytes.
1868    Version 7.1 24-Apr-07
1869    ---------------------
1871     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1872        that is more "standard", making use of automake and other Autotools. There
1873        is some re-arrangement of the files and adjustment of comments consequent
1874        on this.
1876     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1877        for recursive directory scanning broke on some systems because the files
1878        are not scanned in any specific order and on different systems the order
1879        was different. A call to "sort" has been inserted into RunGrepTest for the
1880        approprate test as a short-term fix. In the longer term there may be an
1881        alternative.
1883     3. I had an email from Eric Raymond about problems translating some of PCRE's
1884        man pages to HTML (despite the fact that I distribute HTML pages, some
1885        people do their own conversions for various reasons). The problems
1886        concerned the use of low-level troff macros .br and .in. I have therefore
1887        removed all such uses from the man pages (some were redundant, some could
1888        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1889        HTML has been updated to handle .nf/.fi and to complain if it encounters
1890        .br or .in.
1892     4. Updated comments in configure.ac that get placed in config.h.in and also
1893        arranged for config.h to be included in the distribution, with the name
1894        config.h.generic, for the benefit of those who have to compile without
1895        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1897     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1898        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1899        makevp.bat for the current PCRE, using the additional files
1900        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1902     6. A Windows user reported a minor discrepancy with test 2, which turned out
1903        to be caused by a trailing space on an input line that had got lost in his
1904        copy. The trailing space was an accident, so I've just removed it.
1906     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1907        that is needed.
1909     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1910        as "const" (a) because they are and (b) because it helps the PHP
1911        maintainers who have recently made a script to detect big data structures
1912        in the php code that should be moved to the .rodata section. I remembered
1913        to update Builducptable as well, so it won't revert if ucptable.h is ever
1914        re-created.
1916     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1917        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1918        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1919        support is not required. This saves 1.5-2K of code, which is important in
1920        some applications.
1922        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1923        so as not to refer to the tables, even though these functions will never be
1924        called when UTF-8 support is disabled. Otherwise there are problems with a
1925        shared library.
1927    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1929        (a) It was defining its arguments as char * instead of void *.
1931        (b) It was assuming that all moves were upwards in memory; this was true
1932            a long time ago when I wrote it, but is no longer the case.
1934        The emulated memove() is provided for those environments that have neither
1935        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1936        is clearly not the case, as these two bugs were recently reported.
1938    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1939        and Detrail to create the HTML documentation, the .txt form of the man
1940        pages, and it removes trailing spaces from listed files. It also creates
1941        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1942        case, it wraps all the #defines with #ifndefs. This script should be run
1943        before "make dist".
1945    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1946        with Unicode property support.
1948        (a) For a maximizing quantifier, if the two different cases of the
1949            character were of different lengths in their UTF-8 codings (there are
1950            some cases like this - I found 11), and the matching function had to
1951            back up over a mixture of the two cases, it incorrectly assumed they
1952            were both the same length.
1954        (b) When PCRE was configured to use the heap rather than the stack for
1955            recursion during matching, it was not correctly preserving the data for
1956            the other case of a UTF-8 character when checking ahead for a match
1957            while processing a minimizing repeat. If the check also involved
1958            matching a wide character, but failed, corruption could cause an
1959            erroneous result when trying to check for a repeat of the original
1960            character.
1962    13. Some tidying changes to the testing mechanism:
1964        (a) The RunTest script now detects the internal link size and whether there
1965            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1966            values substituted by "configure". (The RunGrepTest script already did
1967            this for UTF-8.) The configure.ac script no longer substitutes the
1968            relevant variables.
1970        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1971            with length and offset values. This means that the output is different
1972            for different internal link sizes. Test 2 is skipped for link sizes
1973            other than 2 because of this, bypassing the problem. Unfortunately,
1974            there was also a test in test 3 (the locale tests) that used /B and
1975            failed for link sizes other than 2. Rather than cut the whole test out,
1976            I have added a new /Z option to pcretest that replaces the length and
1977            offset values with spaces. This is now used to make test 3 independent
1978            of link size. (Test 2 will be tidied up later.)
1980    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1981        segmentation fault instead of returning the appropriate error message.
1983    15. In multiline mode when the newline sequence was set to "any", the pattern
1984        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1985        This doesn't seem right; it now treats the CRLF combination as the line
1986        ending, and so does not match in that case. It's only a pattern such as ^$
1987        that would hit this one: something like ^ABC$ would have failed after \r
1988        and then tried again after \r\n.
1990    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1991        in an attempt to make files that differ only in their line terminators
1992        compare equal. This works on Linux.
1994    17. Under certain error circumstances pcregrep might try to free random memory
1995        as it exited. This is now fixed, thanks to valgrind.
1997    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1998        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1999        was because its rules for how to advance for /g after matching an empty
2000        string at the end of a line did not allow for this case. They now check for
2001        it specially.
2003    20. pcretest is supposed to handle patterns and data of any length, by
2004        extending its buffers when necessary. It was getting this wrong when the
2005        buffer for a data line had to be extended.
2007    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2008        CRLF as a newline sequence.
2010    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2011        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2012        I have nevertheless tidied it up.
2014    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2016    24. Added a man page for pcre-config.
2019    Version 7.0 19-Dec-06
2020    ---------------------
2022     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2023        moving to gcc 4.1.1.
2025     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2026        sys/time.h, which is documented as needed for this function. It doesn't
2027        seem to matter on Linux, but it showed up on some releases of OS X.
2029     3. It seems that there are systems where bytes whose values are greater than
2030        127 match isprint() in the "C" locale. The "C" locale should be the
2031        default when a C program starts up. In most systems, only ASCII printing
2032        characters match isprint(). This difference caused the output from pcretest
2033        to vary, making some of the tests fail. I have changed pcretest so that:
2035        (a) When it is outputting text in the compiled version of a pattern, bytes
2036            other than 32-126 are always shown as hex escapes.
2038        (b) When it is outputting text that is a matched part of a subject string,
2039            it does the same, unless a different locale has been set for the match
2040            (using the /L modifier). In this case, it uses isprint() to decide.
2042     4. Fixed a major bug that caused incorrect computation of the amount of memory
2043        required for a compiled pattern when options that changed within the
2044        pattern affected the logic of the preliminary scan that determines the
2045        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2046        that the computed length was too small. The symptoms of this bug were
2047        either the PCRE error "internal error: code overflow" from pcre_compile(),
2048        or a glibc crash with a message such as "pcretest: free(): invalid next
2049        size (fast)". Examples of patterns that provoked this bug (shown in
2050        pcretest format) are:
2052          /(?-x: )/x
2053          /(?x)(?-x: \s*#\s*)/
2054          /((?i)[\x{c0}])/8
2055          /(?i:[\x{c0}])/8
2057        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2058        is now done differently.
2060     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2061        wrapper classes; (b) implement a new function in the C++ scanner that is
2062        more efficient than the old way of doing things because it avoids levels of
2063        recursion in the regex matching; (c) add a paragraph to the documentation
2064        for the FullMatch() function.
2066     6. The escape sequence \n was being treated as whatever was defined as
2067        "newline". Not only was this contrary to the documentation, which states
2068        that \n is character 10 (hex 0A), but it also went horribly wrong when
2069        "newline" was defined as CRLF. This has been fixed.
2071     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2072        was being set to -1 for the "end of line" case (supposedly a value that no
2073        character can have). Though this value is never used (the check for end of
2074        line is "zero bytes in current character"), it caused compiler complaints.
2075        I've changed it to 0xffffffff.
2077     8. In pcre_version.c, the version string was being built by a sequence of
2078        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2079        string (as it is for production releases) called a macro with an empty
2080        argument. The C standard says the result of this is undefined. The gcc
2081        compiler treats it as an empty string (which was what was wanted) but it is
2082        reported that Visual C gives an error. The source has been hacked around to
2083        avoid this problem.
2085     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2086        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2087        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2088        of them did).
2090    10. Originally, pcretest opened its input and output without "b"; then I was
2091        told that "b" was needed in some environments, so it was added for release
2092        5.0 to both the input and output. (It makes no difference on Unix-like
2093        systems.) Later I was told that it is wrong for the input on Windows. I've
2094        now abstracted the modes into two macros, to make it easier to fiddle with
2095        them, and removed "b" from the input mode under Windows.
2097    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2099    12. Added -help and --help to pcretest as an official way of being reminded
2100        of the options.
2102    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2103        and pcrecpp.cc because they annoy compilers at high warning levels.
2105    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2107    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2108        scripts are not C programs :-) and which was not noticed because it works
2109        on Linux.
2111    16. pcretest is supposed to handle any length of pattern and data line (as one
2112        line or as a continued sequence of lines) by extending its input buffer if
2113        necessary. This feature was broken for very long pattern lines, leading to
2114        a string of junk being passed to pcre_compile() if the pattern was longer
2115        than about 50K.
2117    17. I have done a major re-factoring of the way pcre_compile() computes the
2118        amount of memory needed for a compiled pattern. Previously, there was code
2119        that made a preliminary scan of the pattern in order to do this. That was
2120        OK when PCRE was new, but as the facilities have expanded, it has become
2121        harder and harder to keep it in step with the real compile phase, and there
2122        have been a number of bugs (see for example, 4 above). I have now found a
2123        cunning way of running the real compile function in a "fake" mode that
2124        enables it to compute how much memory it would need, while actually only
2125        ever using a few hundred bytes of working memory and without too many
2126        tests of the mode. This should make future maintenance and development
2127        easier. A side effect of this work is that the limit of 200 on the nesting
2128        depth of parentheses has been removed (though this was never a serious
2129        limitation, I suspect). However, there is a downside: pcre_compile() now
2130        runs more slowly than before (30% or more, depending on the pattern). I
2131        hope this isn't a big issue. There is no effect on runtime performance.
2133    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2134        newline (only possible for the last line of a file) and it was a
2135        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2137    19. Added additional timing features to pcretest. (1) The -tm option now times
2138        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2139        separate command line item, by a number that specifies the number of
2140        repeats to use when timing. The default is 50000; this gives better
2141        precision, but takes uncomfortably long for very large patterns.
2143    20. Extended pcre_study() to be more clever in cases where a branch of a
2144        subpattern has no definite first character. For example, (a*|b*)[cd] would
2145        previously give no result from pcre_study(). Now it recognizes that the
2146        first character must be a, b, c, or d.
2148    21. There was an incorrect error "recursive call could loop indefinitely" if
2149        a subpattern (or the entire pattern) that was being tested for matching an
2150        empty string contained only one non-empty item after a nested subpattern.
2151        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2152        incorrectly, because the \d was being skipped in the check.
2154    22. The pcretest program now has a new pattern option /B and a command line
2155        option -b, which is equivalent to adding /B to every pattern. This causes
2156        it to show the compiled bytecode, without the additional information that
2157        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2158        is the same as /B/I).
2160    23. A new optimization is now able automatically to treat some sequences such
2161        as a*b as a*+b. More specifically, if something simple (such as a character
2162        or a simple class like \d) has an unlimited quantifier, and is followed by
2163        something that cannot possibly match the quantified thing, the quantifier
2164        is automatically "possessified".
2166    24. A recursive reference to a subpattern whose number was greater than 39
2167        went wrong under certain circumstances in UTF-8 mode. This bug could also
2168        have affected the operation of pcre_study().
2170    25. Realized that a little bit of performance could be had by replacing
2171        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2173    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2175    27. Possessive quantifiers such as a++ were previously implemented by turning
2176        them into atomic groups such as ($>a+). Now they have their own opcodes,
2177        which improves performance. This includes the automatically created ones
2178        from 23 above.
2180    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2181        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2182        the first matched character to be a colon. This applied both to named and
2183        numbered groups.
2185    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2187    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2188        building PCRE on Windows easier, so I have included it in the distribution.
2190    31. There is now a check in pcretest against a ridiculously large number being
2191        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2192        loop, the loop is abandoned.
2194    32. Forward references to subpatterns in conditions such as (?(2)...) where
2195        subpattern 2 is defined later cause pcre_compile() to search forwards in
2196        the pattern for the relevant set of parentheses. This search went wrong
2197        when there were unescaped parentheses in a character class, parentheses
2198        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2200    33. "Subroutine" calls and backreferences were previously restricted to
2201        referencing subpatterns earlier in the regex. This restriction has now
2202        been removed.
2204    34. Added a number of extra features that are going to be in Perl 5.10. On the
2205        whole, these are just syntactic alternatives for features that PCRE had
2206        previously implemented using the Python syntax or my own invention. The
2207        other formats are all retained for compatibility.
2209        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2210            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2211            also .NET compatible.
2213        (b) A recursion or subroutine call to a named group can now be defined as
2214            (?&name) as well as (?P>name).
2216        (c) A backreference to a named group can now be defined as \k<name> or
2217            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2218            5.10, are also .NET compatible.
2220        (d) A conditional reference to a named group can now use the syntax
2221            (?(<name>) or (?('name') as well as (?(name).
2223        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2224            groups (named and numbered) that are never evaluated inline, but can be
2225            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2226            is always false. There may be only one alternative in such a group.
2228        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2229            as the simple (?(R). The condition is true only if the most recent
2230            recursion is that of the given number or name. It does not search out
2231            through the entire recursion stack.
2233        (g) The escape \gN or \g{N} has been added, where N is a positive or
2234            negative number, specifying an absolute or relative reference.
2236    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2237        some "unreachable code" warnings.
2239    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2240        things, this adds five new scripts.
2242    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2243        There were also incompatibilities regarding the handling of \Q..\E inside
2244        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2245        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2247    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2248        matches an empty string, and forcibly breaks the loop. There were bugs in
2249        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2250        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2251        separate and independent bugs (that affected different cases) have been
2252        fixed.
2254    39. Refactored the code to abolish the use of different opcodes for small
2255        capturing bracket numbers. This is a tidy that I avoided doing when I
2256        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2257        The new approach is not only tidier, it makes it possible to reduce the
2258        memory needed to fix the previous bug (38).
2260    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2261        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2262        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2263        mode.
2265    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2266        report.
2268    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2269        copy construction and assignment in the C++ wrapper.
2271    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2272        couple of bugs that could have given wrong results in the "--newline=crlf"
2273        case.
2275    44. Added a number of casts and did some reorganization of signed/unsigned int
2276        variables following suggestions from Dair Grant. Also renamed the variable
2277        "this" as "item" because it is a C++ keyword.
2279    45. Arranged for dftables to add
2281          #include "pcre_internal.h"
2283        to pcre_chartables.c because without it, gcc 4.x may remove the array
2284        definition from the final binary if PCRE is built into a static library and
2285        dead code stripping is activated.
2287    46. For an unanchored pattern, if a match attempt fails at the start of a
2288        newline sequence, and the newline setting is CRLF or ANY, and the next two
2289        characters are CRLF, advance by two characters instead of one.
2292  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
2293  ---------------------  ---------------------

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