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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  Version 8.20 23-Sep-2011
5    ------------------------
7    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8        a POSIX class. After further experiments with Perl, which convinced me that
9        Perl has bugs and confusions, a closing square bracket is no longer allowed
10        in a POSIX name. This bug also affected patterns with classes that started
11        with full stops.
13    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
14        captured substring, but while checking the failing first alternative,
15        substring 1 is temporarily captured. If the output vector supplied to
16        pcre_exec() was not big enough for this capture, the yield of the function
17        was still zero ("insufficient space for captured substrings"). This cannot
18        be totally fixed without adding another stack variable, which seems a lot
19        of expense for a edge case. However, I have improved the situation in cases
20        such as /(a)(b)x|abc/ matched against "abc", where the return code
21        indicates that fewer than the maximum number of slots in the ovector have
22        been set.
24    3.  Related to (2) above: when there are more back references in a pattern than
25        slots in the output vector, pcre_exec() uses temporary memory during
26        matching, and copies in the captures as far as possible afterwards. It was
27        using the entire output vector, but this conflicts with the specification
28        that only 2/3 is used for passing back captured substrings. Now it uses
29        only the first 2/3, for compatibility. This is, of course, another edge
30        case.
32    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
33        main code base, and can be used by building with --enable-jit. When this is
34        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
35        runtime --no-jit option is given.
37    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
38        ovector, the return from the function was zero, implying that there were
39        other matches that did not fit. The correct "exactly full" value is now
40        returned.
42    6.  If a subpattern that was called recursively or as a subroutine contained
43        (*PRUNE) or any other control that caused it to give a non-standard return,
44        invalid errors such as "Error -26 (nested recursion at the same subject
45        position)" or even infinite loops could occur.
47    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
48        computing the minimum length on reaching *ACCEPT, and so ended up with the
49        wrong value of 1 rather than 0. Further investigation indicates that
50        computing a minimum subject length in the presence of *ACCEPT is difficult
51        (think back references, subroutine calls), and so I have changed the code
52        so that no minimum is registered for a pattern that contains *ACCEPT.
54    8.  If (*THEN) was present in the first (true) branch of a conditional group,
55        it was not handled as intended. [But see 16 below.]
57    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
58        Sheri Pierce.
60    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
61        the first byte in a match must be "a".
63    11. Change 17 for 8.13 increased the recursion depth for patterns like
64        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
65        pattern contains any instances of (*THEN). If it does not, the old
66        optimizations are restored. It would be nice to do this on a per-group
67        basis, but at the moment that is not feasible.
69    12. In some environments, the output of pcretest -C is CRLF terminated. This
70        broke RunTest's code that checks for the link size. A single white space
71        after the value is now allowed for.
73    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
74        For "fr", it uses the Windows-specific input and output files.
76    14. If (*THEN) appeared in a group that was called recursively or as a
77        subroutine, it did not work as intended. [But see next item.]
79    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
80        pattern fragments (but not containing any | characters). If A and B are
81        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
82        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
83        D. In other words, Perl considers parentheses that do not contain any |
84        characters to be part of a surrounding alternative, whereas PCRE was
85        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
86        differently. PCRE now behaves in the same way as Perl, except in the case
87        of subroutine/recursion calls such as (?1) which have in any case always
88        been different (but PCRE had them first :-).
90    16. Related to 15 above: Perl does not treat the | in a conditional group as
91        creating alternatives. Such a group is treated in the same way as an
92        ordinary group without any | characters when processing (*THEN). PCRE has
93        been changed to match Perl's behaviour.
95    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
96        RunGrepTest script failed.
98    18. Change 22 for version 13 caused atomic groups to use more stack. This is
99        inevitable for groups that contain captures, but it can lead to a lot of
100        stack use in large patterns. The old behaviour has been restored for atomic
101        groups that do not contain any capturing parentheses.
104    Version 8.13 16-Aug-2011
105    ------------------------
107    1.  The Unicode data tables have been updated to Unicode 6.0.0.
109    2.  Two minor typos in pcre_internal.h have been fixed.
111    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
112        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
113        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
115    4.  There were a number of related bugs in the code for matching backrefences
116        caselessly in UTF-8 mode when codes for the characters concerned were
117        different numbers of bytes. For example, U+023A and U+2C65 are an upper
118        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
119        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
120        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
121        2-byte code at the end of the subject (it thought there wasn't enough data
122        left).
124    5.  Comprehensive information about what went wrong is now returned by
125        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
126        as the output vector has at least 2 elements. The offset of the start of
127        the failing character and a reason code are placed in the vector.
129    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
130        now returned is for the first byte of the failing character, instead of the
131        last byte inspected. This is an incompatible change, but I hope it is small
132        enough not to be a problem. It makes the returned offset consistent with
133        pcre_exec() and pcre_dfa_exec().
135    7.  pcretest now gives a text phrase as well as the error number when
136        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
137        failure, the offset and reason code are output.
139    8.  When \R was used with a maximizing quantifier it failed to skip backwards
140        over a \r\n pair if the subsequent match failed. Instead, it just skipped
141        back over a single character (\n). This seems wrong (because it treated the
142        two characters as a single entity when going forwards), conflicts with the
143        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
144        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
145        has been changed.
147    9.  Some internal refactoring has changed the processing so that the handling
148        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
149        time (the PCRE_DOTALL option was changed this way some time ago: version
150        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
151        which was always a bit of a fudge. It also means that there is one less
152        argument for the match() function, which reduces its stack requirements
153        slightly. This change also fixes an incompatibility with Perl: the pattern
154        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
156    10. More internal refactoring has drastically reduced the number of recursive
157        calls to match() for possessively repeated groups such as (abc)++ when
158        using pcre_exec().
160    11. While implementing 10, a number of bugs in the handling of groups were
161        discovered and fixed:
163        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
164        (a|)*(?1) gave a compile-time internal error.
165        ((a|)+)+  did not notice that the outer group could match an empty string.
166        (^a|^)+   was not marked as anchored.
167        (.*a|.*)+ was not marked as matching at start or after a newline.
169    12. Yet more internal refactoring has removed another argument from the match()
170        function. Special calls to this function are now indicated by setting a
171        value in a variable in the "match data" data block.
173    13. Be more explicit in pcre_study() instead of relying on "default" for
174        opcodes that mean there is no starting character; this means that when new
175        ones are added and accidentally left out of pcre_study(), testing should
176        pick them up.
178    14. The -s option of pcretest has been documented for ages as being an old
179        synonym of -m (show memory usage). I have changed it to mean "force study
180        for every regex", that is, assume /S for every regex. This is similar to -i
181        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
182        using it. It makes it easier to run collections of tests with and without
183        study enabled, and thereby test pcre_study() more easily. All the standard
184        tests are now run with and without -s (but some patterns can be marked as
185        "never study" - see 20 below).
187    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
188        restoration of the capturing data to the outer values was not happening
189        correctly.
191    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
192        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
193        pattern had matched an empty string, and so incorrectly returned a no
194        match.
196    17. There was optimizing code for the last branch of non-capturing parentheses,
197        and also for the obeyed branch of a conditional subexpression, which used
198        tail recursion to cut down on stack usage. Unfortunately, now that there is
199        the possibility of (*THEN) occurring in these branches, tail recursion is
200        no longer possible because the return has to be checked for (*THEN). These
201        two optimizations have therefore been removed. [But see 8.20/11 above.]
203    18. If a pattern containing \R was studied, it was assumed that \R always
204        matched two bytes, thus causing the minimum subject length to be
205        incorrectly computed because \R can also match just one byte.
207    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
208        was incorrectly computed.
210    20. If /S is present twice on a test pattern in pcretest input, it now
211        *disables* studying, thereby overriding the use of -s on the command line
212        (see 14 above). This is necessary for one or two tests to keep the output
213        identical in both cases.
215    21. When (*ACCEPT) was used in an assertion that matched an empty string and
216        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
218    22. When an atomic group that contained a capturing parenthesis was
219        successfully matched, but the branch in which it appeared failed, the
220        capturing was not being forgotten if a higher numbered group was later
221        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
222        group 1 to "a", when in fact it should be unset. This applied to multi-
223        branched capturing and non-capturing groups, repeated or not, and also to
224        positive assertions (capturing in negative assertions does not happen
225        in PCRE) and also to nested atomic groups.
227    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
228        subject after a captured substring, to make it easier to tell which of a
229        number of identical substrings has been captured.
231    24. The way atomic groups are processed by pcre_exec() has been changed so that
232        if they are repeated, backtracking one repetition now resets captured
233        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
234        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
235        "aaa". Previously, it would have been "a". As part of this code
236        refactoring, the way recursive calls are handled has also been changed.
238    25. If an assertion condition captured any substrings, they were not passed
239        back unless some other capturing happened later. For example, if
240        (?(?=(a))a) was matched against "a", no capturing was returned.
242    26. When studying a pattern that contained subroutine calls or assertions,
243        the code for finding the minimum length of a possible match was handling
244        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
245        group 1 called group 2 while simultaneously a separate group 2 called group
246        1). A stack overflow occurred in this case. I have fixed this by limiting
247        the recursion depth to 10.
249    27. Updated RunTest.bat in the distribution to the version supplied by Tom
250        Fortmann. This supports explicit test numbers on the command line, and has
251        argument validation and error reporting.
253    28. An instance of \X with an unlimited repeat could fail if at any point the
254        first character it looked at was a mark character.
256    29. Some minor code refactoring concerning Unicode properties and scripts
257        should reduce the stack requirement of match() slightly.
259    30. Added the '=' option to pcretest to check the setting of unused capturing
260        slots at the end of the pattern, which are documented as being -1, but are
261        not included in the return count.
263    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
264        compiled something random. Now it gives a compile-time error (as does
265        Perl).
267    32. A *MARK encountered during the processing of a positive assertion is now
268        recorded and passed back (compatible with Perl).
270    33. If --only-matching or --colour was set on a pcregrep call whose pattern
271        had alternative anchored branches, the search for a second match in a line
272        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
273        matched the line "0102" twice. The same bug affected patterns that started
274        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
275        twice.
277    34. Previously, PCRE did not allow quantification of assertions. However, Perl
278        does, and because of capturing effects, quantifying parenthesized
279        assertions may at times be useful. Quantifiers are now allowed for
280        parenthesized assertions.
282    35. A minor code tidy in pcre_compile() when checking options for \R usage.
284    36. \g was being checked for fancy things in a character class, when it should
285        just be a literal "g".
287    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
288        appearance of a nested POSIX class supersedes an apparent external class.
289        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
290        unescaped square brackets may also appear as part of class names. For
291        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
292        more like Perl. (But see 8.20/1 above.)
294    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
295        was because it thought it was \N{name}, which is not supported).
297    39. Add minix to OS list not supporting the -S option in pcretest.
299    40. PCRE tries to detect cases of infinite recursion at compile time, but it
300        cannot analyze patterns in sufficient detail to catch mutual recursions
301        such as ((?1))((?2)). There is now a runtime test that gives an error if a
302        subgroup is called recursively as a subpattern for a second time at the
303        same position in the subject string. In previous releases this might have
304        been caught by the recursion limit, or it might have run out of stack.
306    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
307        happen only once. PCRE was, however incorrectly giving a compile time error
308        "recursive call could loop indefinitely" because it cannot analyze the
309        pattern in sufficient detail. The compile time test no longer happens when
310        PCRE is compiling a conditional subpattern, but actual runaway loops are
311        now caught at runtime (see 40 above).
313    42. It seems that Perl allows any characters other than a closing parenthesis
314        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
315        has been changed to be the same.
317    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
318        as not to get warnings when autogen.sh is called. Also changed
319        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
321    44. To help people who use pcregrep to scan files containing exceedingly long
322        lines, the following changes have been made:
324        (a) The default value of the buffer size parameter has been increased from
325            8K to 20K. (The actual buffer used is three times this size.)
327        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
328            PCRE is built.
330        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
331            to be set at run time.
333        (d) Numerical values in pcregrep options can be followed by K or M, for
334            example --buffer-size=50K.
336        (e) If a line being scanned overflows pcregrep's buffer, an error is now
337            given and the return code is set to 2.
339    45. Add a pointer to the latest mark to the callout data block.
341    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
342        partial match of an empty string instead of no match. This was specific to
343        the use of ".".
345    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
346        complete match instead of a partial match. This bug was dependent on both
347        the PCRE_UTF8 and PCRE_DOTALL options being set.
349    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
350        starting byte set, because \b was not being ignored.
353    Version 8.12 15-Jan-2011
354    ------------------------
356    1.  Fixed some typos in the markup of the man pages, and wrote a script that
357        checks for such things as part of the documentation building process.
359    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
360        --match-limit and --recursion-limit options (added for 8.11). In
361        particular, this made one of the standard tests fail. (The integer value
362        went into the wrong half of a long int.)
364    3.  If the --colour option was given to pcregrep with -v (invert match), it
365        did strange things, either producing crazy output, or crashing. It should,
366        of course, ignore a request for colour when reporting lines that do not
367        match.
369    4.  Another pcregrep bug caused similar problems if --colour was specified with
370        -M (multiline) and the pattern match finished with a line ending.
372    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
373        matched in multiline mode, the following line was shown as part of the
374        match. This seems wrong, so I have changed it.
376    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
377        the check for further matches in the same line (so they could be coloured)
378        to overrun the end of the current line. If another match was found, it was
379        incorrectly shown (and then shown again when found in the next line).
381    7.  If pcregrep was compiled under Windows, there was a reference to the
382        function pcregrep_exit() before it was defined. I am assuming this was
383        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
384        reported by a user. I've moved the definition above the reference.
387    Version 8.11 10-Dec-2010
388    ------------------------
390    1.  (*THEN) was not working properly if there were untried alternatives prior
391        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
392        backtracked to try for "b" instead of moving to the next alternative branch
393        at the same level (in this case, to look for "c"). The Perl documentation
394        is clear that when (*THEN) is backtracked onto, it goes to the "next
395        alternative in the innermost enclosing group".
397    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
398        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
399        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
400        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
401        (*THEN).
403    3.  If \s appeared in a character class, it removed the VT character from
404        the class, even if it had been included by some previous item, for example
405        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
406        of \s, but is part of the POSIX "space" class.)
408    4.  A partial match never returns an empty string (because you can always
409        match an empty string at the end of the subject); however the checking for
410        an empty string was starting at the "start of match" point. This has been
411        changed to the "earliest inspected character" point, because the returned
412        data for a partial match starts at this character. This means that, for
413        example, /(?<=abc)def/ gives a partial match for the subject "abc"
414        (previously it gave "no match").
416    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
417        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
418        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
419        has an implication that the given string is incomplete (because a partial
420        match is preferred over a full match). For this reason, these items now
421        give a partial match in this situation. [Aside: previously, the one case
422        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
423        match rather than a full match, which was wrong by the old rules, but is
424        now correct.]
426    6.  There was a bug in the handling of #-introduced comments, recognized when
427        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
428        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
429        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
430        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
431        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
432        places in pcre_compile().
434    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
435        comments when looking ahead for named forward references to subpatterns,
436        the only newline sequence it recognized was NL. It now handles newlines
437        according to the set newline convention.
439    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
440        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
441        cater for a lack of strerror(). These oversights have been fixed.
443    9.  Added --match-limit and --recursion-limit to pcregrep.
445    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
447    11. When the -o option was used, pcregrep was setting a return code of 1, even
448        when matches were found, and --line-buffered was not being honoured.
450    12. Added an optional parentheses number to the -o and --only-matching options
451        of pcregrep.
453    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
454        can match an empty string. The code to do it in pcretest and pcredemo
455        needed fixing:
457        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
458            only one byte after an empty string match just before CRLF (this case
459            just got forgotten; "any" and "anycrlf" were OK).
461        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
462            mode when an empty string match preceded an ASCII character followed by
463            a non-ASCII character. (The code for advancing by one character rather
464            than one byte was nonsense.)
466        (c) The pcredemo.c sample program did not have any code at all to handle
467            the cases when CRLF is a valid newline sequence.
469    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
470        as a starting offset was within the subject string. There is now a new
471        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
472        negative or greater than the length of the string. In order to test this,
473        pcretest is extended to allow the setting of negative starting offsets.
475    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
476        starting offset points to the beginning of a UTF-8 character was
477        unnecessarily clumsy. I tidied it up.
479    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
480        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
482    17. Nobody had reported that the --include_dir option, which was added in
483        release 7.7 should have been called --include-dir (hyphen, not underscore)
484        for compatibility with GNU grep. I have changed it to --include-dir, but
485        left --include_dir as an undocumented synonym, and the same for
486        --exclude-dir, though that is not available in GNU grep, at least as of
487        release 2.5.4.
489    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
490        characters from a string of bytes) have been redefined so as not to use
491        loops, in order to improve performance in some environments. At the same
492        time, I abstracted some of the common code into auxiliary macros to save
493        repetition (this should not affect the compiled code).
495    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
496        compile-time error is now given if \c is not followed by an ASCII
497        character, that is, a byte less than 128. (In EBCDIC mode, the code is
498        different, and any byte value is allowed.)
500    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
501        START_OPTIMIZE option, which is now allowed at compile time - but just
502        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
503        to pcregrep and other applications that have no direct access to PCRE
504        options. The new /Y option in pcretest sets this option when calling
505        pcre_compile().
507    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
508        back references. Groups containing recursive back references were forced to
509        be atomic by that change, but in the case of named groups, the amount of
510        memory required was incorrectly computed, leading to "Failed: internal
511        error: code overflow". This has been fixed.
513    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
514        pcretest.c, to avoid build problems in some Borland environments.
517    Version 8.10 25-Jun-2010
518    ------------------------
520    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
521        THEN.
523    2.  (*ACCEPT) was not working when inside an atomic group.
525    3.  Inside a character class, \B is treated as a literal by default, but
526        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
527        causes the error). The code is unchanged, but I tidied the documentation.
529    4.  Inside a character class, PCRE always treated \R and \X as literals,
530        whereas Perl faults them if its -w option is set. I have changed PCRE so
531        that it faults them when PCRE_EXTRA is set.
533    5.  Added support for \N, which always matches any character other than
534        newline. (It is the same as "." when PCRE_DOTALL is not set.)
536    6.  When compiling pcregrep with newer versions of gcc which may have
537        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
538        declared with attribute warn_unused_result" were given. Just casting the
539        result to (void) does not stop the warnings; a more elaborate fudge is
540        needed. I've used a macro to implement this.
542    7.  Minor change to pcretest.c to avoid a compiler warning.
544    8.  Added four artifical Unicode properties to help with an option to make
545        \s etc use properties (see next item). The new properties are: Xan
546        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
548    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
549        use Unicode properties. (*UCP) at the start of a pattern can be used to set
550        this option. Modified pcretest to add /W to test this facility. Added
551        REG_UCP to make it available via the POSIX interface.
553    10. Added --line-buffered to pcregrep.
555    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
556        studied, and the match started with a letter with a code point greater than
557        127 whose first byte was different to the first byte of the other case of
558        the letter, the other case of this starting letter was not recognized
559        (#976).
561    12. If a pattern that was studied started with a repeated Unicode property
562        test, for example, \p{Nd}+, there was the theoretical possibility of
563        setting up an incorrect bitmap of starting bytes, but fortunately it could
564        not have actually happened in practice until change 8 above was made (it
565        added property types that matched character-matching opcodes).
567    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
568        possible starting bytes for non-anchored patterns.
570    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
571        \R, and also a number of cases that involve Unicode properties, both
572        explicit and implicit when PCRE_UCP is set.
574    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
575        input, it could crash or give wrong results if characters with values
576        greater than 0xc0 were present in the subject string. (Detail: it assumed
577        UTF-8 input when processing these items.)
579    16. Added a lot of (int) casts to avoid compiler warnings in systems where
580        size_t is 64-bit (#991).
582    17. Added a check for running out of memory when PCRE is compiled with
583        --disable-stack-for-recursion (#990).
585    18. If the last data line in a file for pcretest does not have a newline on
586        the end, a newline was missing in the output.
588    19. The default pcre_chartables.c file recognizes only ASCII characters (values
589        less than 128) in its various bitmaps. However, there is a facility for
590        generating tables according to the current locale when PCRE is compiled. It
591        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
592        characters, are recognized by isspace() and therefore were getting set in
593        these tables, and indeed these tables seem to approximate to ISO 8859. This
594        caused a problem in UTF-8 mode when pcre_study() was used to create a list
595        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
596        which of course cannot start UTF-8 characters. I have changed the code so
597        that only real ASCII characters (less than 128) and the correct starting
598        bytes for UTF-8 encodings are set for characters greater than 127 when in
599        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
600        altogether.)
602    20. Added the /T option to pcretest so as to be able to run tests with non-
603        standard character tables, thus making it possible to include the tests
604        used for 19 above in the standard set of tests.
606    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
607        reference to a subpattern the other side of a comment that contains an
608        opening parenthesis caused either an internal compiling error, or a
609        reference to the wrong subpattern.
612    Version 8.02 19-Mar-2010
613    ------------------------
615    1.  The Unicode data tables have been updated to Unicode 5.2.0.
617    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
618        configured.
620    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
621        original author of that file, following a query about its status.
623    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
624        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
626    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
627        quantifier applied to a forward-referencing subroutine call, could compile
628        incorrect code or give the error "internal error: previously-checked
629        referenced subpattern not found".
631    6.  Both MS Visual Studio and Symbian OS have problems with initializing
632        variables to point to external functions. For these systems, therefore,
633        pcre_malloc etc. are now initialized to local functions that call the
634        relevant global functions.
636    7.  There were two entries missing in the vectors called coptable and poptable
637        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
638        I've fixed the data, and added a kludgy way of testing at compile time that
639        the lengths are correct (equal to the number of opcodes).
641    8.  Following on from 7, I added a similar kludge to check the length of the
642        eint vector in pcreposix.c.
644    9.  Error texts for pcre_compile() are held as one long string to avoid too
645        much relocation at load time. To find a text, the string is searched,
646        counting zeros. There was no check for running off the end of the string,
647        which could happen if a new error number was added without updating the
648        string.
650    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
652    11. \K was not working if it appeared in an atomic group or in a group that
653        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
654        \K is "not well defined" if used in an assertion. PCRE now accepts it if
655        the assertion is positive, but not if it is negative.
657    12. Change 11 fortuitously reduced the size of the stack frame used in the
658        "match()" function of pcre_exec.c by one pointer. Forthcoming
659        implementation of support for (*MARK) will need an extra pointer on the
660        stack; I have reserved it now, so that the stack frame size does not
661        decrease.
663    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
664        item in branch that calls a recursion is a subroutine call - as in the
665        second branch in the above example - was incorrectly given the compile-
666        time error "recursive call could loop indefinitely" because pcre_compile()
667        was not correctly checking the subroutine for matching a non-empty string.
669    14. The checks for overrunning compiling workspace could trigger after an
670        overrun had occurred. This is a "should never occur" error, but it can be
671        triggered by pathological patterns such as hundreds of nested parentheses.
672        The checks now trigger 100 bytes before the end of the workspace.
674    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
677    Version 8.01 19-Jan-2010
678    ------------------------
680    1.  If a pattern contained a conditional subpattern with only one branch (in
681        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
682        computed the wrong minimum data length (which is of course zero for such
683        subpatterns). This could cause incorrect "no match" results.
685    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
686        the pattern is reset in the first branch, pcre_compile() failed with
687        "internal error: code overflow at offset...". This happened only when
688        the reset was to the original external option setting. (An optimization
689        abstracts leading options settings into an external setting, which was the
690        cause of this.)
692    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
693        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
694        assertion pattern did not match (meaning that the assertion was true), it
695        was incorrectly treated as false if the SKIP had been reached during the
696        matching. This also applied to assertions used as conditions.
698    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
699        assertion subpattern, including such a pattern used as a condition,
700        unpredictable results occurred, instead of the error return
703    5.  The C++ GlobalReplace function was not working like Perl for the special
704        situation when an empty string is matched. It now does the fancy magic
705        stuff that is necessary.
707    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
708        removed. (These were left over from very, very early versions of PCRE.)
710    7.  Some cosmetic changes to the code to make life easier when compiling it
711        as part of something else:
713        (a) Change DEBUG to PCRE_DEBUG.
715        (b) In pcre_compile(), rename the member of the "branch_chain" structure
716            called "current" as "current_branch", to prevent a collision with the
717            Linux macro when compiled as a kernel module.
719        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
720            prevent a collision with the Linux macro when compiled as a kernel
721            module.
723    8.  In pcre_compile() there are some checks for integer overflows that used to
724        cast potentially large values to (double). This has been changed to that
725        when building, a check for int64_t is made, and if it is found, it is used
726        instead, thus avoiding the use of floating point arithmetic. (There is no
727        other use of FP in PCRE.) If int64_t is not found, the fallback is to
728        double.
730    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
731        2005 (difference between two addresses compared to an unsigned value).
733    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
734        custom one, because of the following reported problem in Windows:
736          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
737              under Win32.
738          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
739              therefore missing the function definition.
740          - The compiler thus generates a "C" signature for the test function.
741          - The linker fails to find the "C" function.
742          - PCRE fails to configure if asked to do so against libbz2.
744    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
745        messages were output:
747          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
748          rerunning libtoolize, to keep the correct libtool macros in-tree.
749          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
751        I have done both of these things.
753    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
754        most of the time, it *can* run out if it is given a pattern that contains a
755        runaway infinite recursion. I updated the discussion in the pcrestack man
756        page.
758    13. Now that we have gone to the x.xx style of version numbers, the minor
759        version may start with zero. Using 08 or 09 is a bad idea because users
760        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
761        interpreted as invalid octal numbers. I've updated the previous comment in
762        configure.ac, and also added a check that gives an error if 08 or 09 are
763        used.
765    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
766        causing partial matching to fail when the end of the subject matched \W
767        in a UTF-8 pattern where \W was quantified with a minimum of 3.
769    15. There were some discrepancies between the declarations in pcre_internal.h
770        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
771        their definitions. The declarations used "const uschar *" and the
772        definitions used USPTR. Even though USPTR is normally defined as "const
773        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
774        reported that: "This difference in casting confuses some C++ compilers, for
775        example, SunCC recognizes above declarations as different functions and
776        generates broken code for hbpcre." I have changed the declarations to use
777        USPTR.
779    16. GNU libtool is named differently on some systems. The autogen.sh script now
780        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
781        (FreeBSD).
783    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
784        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
785        comment: "Figure out how to create a longlong from a string: strtoll and
786        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
787        instance, but it only takes 2 args instead of 3!"
789    18. A subtle bug concerned with back references has been fixed by a change of
790        specification, with a corresponding code fix. A pattern such as
791        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
792        refers, was giving matches when it shouldn't. For example, xa=xaaa would
793        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
794        same bug. Such groups have to be quantified to be useful, or contained
795        inside another quantified group. (If there's no repetition, the reference
796        can never match.) The problem arises because, having left the group and
797        moved on to the rest of the pattern, a later failure that backtracks into
798        the group uses the captured value from the final iteration of the group
799        rather than the correct earlier one. I have fixed this in PCRE by forcing
800        any group that contains a reference to itself to be an atomic group; that
801        is, there cannot be any backtracking into it once it has completed. This is
802        similar to recursive and subroutine calls.
805    Version 8.00 19-Oct-09
806    ----------------------
808    1.  The table for translating pcre_compile() error codes into POSIX error codes
809        was out-of-date, and there was no check on the pcre_compile() error code
810        being within the table. This could lead to an OK return being given in
811        error.
813    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
814        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
815        in a Windows environment.
817    3.  The pcregrep --count option prints the count for each file even when it is
818        zero, as does GNU grep. However, pcregrep was also printing all files when
819        --files-with-matches was added. Now, when both options are given, it prints
820        counts only for those files that have at least one match. (GNU grep just
821        prints the file name in this circumstance, but including the count seems
822        more useful - otherwise, why use --count?) Also ensured that the
823        combination -clh just lists non-zero counts, with no names.
825    4.  The long form of the pcregrep -F option was incorrectly implemented as
826        --fixed_strings instead of --fixed-strings. This is an incompatible change,
827        but it seems right to fix it, and I didn't think it was worth preserving
828        the old behaviour.
830    5.  The command line items --regex=pattern and --regexp=pattern were not
831        recognized by pcregrep, which required --regex pattern or --regexp pattern
832        (with a space rather than an '='). The man page documented the '=' forms,
833        which are compatible with GNU grep; these now work.
835    6.  No libpcreposix.pc file was created for pkg-config; there was just
836        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
838    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
839        when UCP support is not needed, by modifying the Python script that
840        generates it from Unicode data files. This should not matter if the module
841        is correctly used as a library, but I received one complaint about 50K of
842        unwanted data. My guess is that the person linked everything into his
843        program rather than using a library. Anyway, it does no harm.
845    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
846        was a minimum greater than 1 for a wide character in a possessive
847        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
848        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
849        character. Chaos in the form of incorrect output or a compiling loop could
850        result.
852    9.  The restrictions on what a pattern can contain when partial matching is
853        requested for pcre_exec() have been removed. All patterns can now be
854        partially matched by this function. In addition, if there are at least two
855        slots in the offset vector, the offset of the earliest inspected character
856        for the match and the offset of the end of the subject are set in them when
857        PCRE_ERROR_PARTIAL is returned.
859    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
860        synonymous with PCRE_PARTIAL, for backwards compatibility, and
861        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
862        and may be more useful for multi-segment matching.
864    11. Partial matching with pcre_exec() is now more intuitive. A partial match
865        used to be given if ever the end of the subject was reached; now it is
866        given only if matching could not proceed because another character was
867        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
868        string "Z", which now yields "no match" instead of "partial match". In the
869        case of pcre_dfa_exec(), "no match" is given if every matching path for the
870        final character ended with (*FAIL).
872    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
873        if the pattern had a "must contain" character that was already found in the
874        earlier partial match, unless partial matching was again requested. For
875        example, with the pattern /dog.(body)?/, the "must contain" character is
876        "g". If the first part-match was for the string "dog", restarting with
877        "sbody" failed. This bug has been fixed.
879    13. The string returned by pcre_dfa_exec() after a partial match has been
880        changed so that it starts at the first inspected character rather than the
881        first character of the match. This makes a difference only if the pattern
882        starts with a lookbehind assertion or \b or \B (\K is not supported by
883        pcre_dfa_exec()). It's an incompatible change, but it makes the two
884        matching functions compatible, and I think it's the right thing to do.
886    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
887        so that the demonstration program is easily available in environments where
888        PCRE has not been installed from source.
890    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
891        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
892        library.
894    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
895        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
896        is not the first non-POSIX option to be added. Clearly some people find
897        these options useful.
899    17. If a caller to the POSIX matching function regexec() passes a non-zero
900        value for nmatch with a NULL value for pmatch, the value of
901        nmatch is forced to zero.
903    18. RunGrepTest did not have a test for the availability of the -u option of
904        the diff command, as RunTest does. It now checks in the same way as
905        RunTest, and also checks for the -b option.
907    19. If an odd number of negated classes containing just a single character
908        interposed, within parentheses, between a forward reference to a named
909        subpattern and the definition of the subpattern, compilation crashed with
910        an internal error, complaining that it could not find the referenced
911        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
912        [The bug was that it was starting one character too far in when skipping
913        over the character class, thus treating the ] as data rather than
914        terminating the class. This meant it could skip too much.]
916    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
917        /g option in pcretest when the pattern contains \K, which makes it possible
918        to have an empty string match not at the start, even when the pattern is
919        anchored. Updated pcretest and pcredemo to use this option.
921    21. If the maximum number of capturing subpatterns in a recursion was greater
922        than the maximum at the outer level, the higher number was returned, but
923        with unset values at the outer level. The correct (outer level) value is
924        now given.
926    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
927        PCRE did not set those parentheses (unlike Perl). I have now found a way to
928        make it do so. The string so far is captured, making this feature
929        compatible with Perl.
931    23. The tests have been re-organized, adding tests 11 and 12, to make it
932        possible to check the Perl 5.10 features against Perl 5.10.
934    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
935        pattern matches a fixed length string. PCRE did not allow this; now it
936        does. Neither allows recursion.
938    25. I finally figured out how to implement a request to provide the minimum
939        length of subject string that was needed in order to match a given pattern.
940        (It was back references and recursion that I had previously got hung up
941        on.) This code has now been added to pcre_study(); it finds a lower bound
942        to the length of subject needed. It is not necessarily the greatest lower
943        bound, but using it to avoid searching strings that are too short does give
944        some useful speed-ups. The value is available to calling programs via
945        pcre_fullinfo().
947    26. While implementing 25, I discovered to my embarrassment that pcretest had
948        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
949        study optimizations had never been tested with that matching function.
950        Oops. What is worse, even when it was passed study data, there was a bug in
951        pcre_dfa_exec() that meant it never actually used it. Double oops. There
952        were also very few tests of studied patterns with pcre_dfa_exec().
954    27. If (?| is used to create subpatterns with duplicate numbers, they are now
955        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
956        on the other side of the coin, they are no longer allowed to have different
957        names, because these cannot be distinguished in PCRE, and this has caused
958        confusion. (This is a difference from Perl.)
960    28. When duplicate subpattern names are present (necessarily with different
961        numbers, as required by 27 above), and a test is made by name in a
962        conditional pattern, either for a subpattern having been matched, or for
963        recursion in such a pattern, all the associated numbered subpatterns are
964        tested, and the overall condition is true if the condition is true for any
965        one of them. This is the way Perl works, and is also more like the way
966        testing by number works.
969    Version 7.9 11-Apr-09
970  ---------------------  ---------------------
972  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 94  Version 7.9 xx-xxx-09 Line 1059  Version 7.9 xx-xxx-09
1059  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1060      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1061      included within another project.      included within another project.
1063  24. Steven Van Ingelgem's patches to add more options to the CMake support,  24. Steven Van Ingelgem's patches to add more options to the CMake support,
1064      slightly modified by me:      slightly modified by me:
1066        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1067            not building pcregrep.            not building pcregrep.
1069        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1070            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1072  25. Forward references, both numeric and by name, in patterns that made use of  25. Forward references, both numeric and by name, in patterns that made use of
1073      duplicate group numbers, could behave incorrectly or give incorrect errors,      duplicate group numbers, could behave incorrectly or give incorrect errors,
1074      because when scanning forward to find the reference group, PCRE was not      because when scanning forward to find the reference group, PCRE was not
1075      taking into account the duplicate group numbers. A pattern such as      taking into account the duplicate group numbers. A pattern such as
1076      ^X(?3)(a)(?|(b)|(q))(Y) is an example.      ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1078  26. Changed a few more instances of "const unsigned char *" to USPTR, making  26. Changed a few more instances of "const unsigned char *" to USPTR, making
1079      the feature of a custom pointer more persuasive (as requested by a user).      the feature of a custom pointer more persuasive (as requested by a user).
1081    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1082        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1083        pre-defined.
1085    28. Added support for (*UTF8) at the start of a pattern.
1087    29. Arrange for flags added by the "release type" setting in CMake to be shown
1088        in the configuration summary.
1091  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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