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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.01 11-Dec-09  Version 8.20 23-Sep-2011
5  ----------------------  ------------------------
7  1.  If a pattern contained a conditional subpattern with only one branch (in  1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8      particular, this includes all (DEFINE) patterns), a call to pcre_study()      a POSIX class. After further experiments with Perl, which convinced me that
9      computed the wrong minimum data length (which is of course zero for such      Perl has bugs and confusions, a closing square bracket is no longer allowed
10      subpatterns).      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 with the much improved version provided by Sheri
58        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  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of  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.
96    Version 8.13 16-Aug-2011
97    ------------------------
99    1.  The Unicode data tables have been updated to Unicode 6.0.0.
101    2.  Two minor typos in pcre_internal.h have been fixed.
103    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
104        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
105        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
107    4.  There were a number of related bugs in the code for matching backrefences
108        caselessly in UTF-8 mode when codes for the characters concerned were
109        different numbers of bytes. For example, U+023A and U+2C65 are an upper
110        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
111        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
112        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
113        2-byte code at the end of the subject (it thought there wasn't enough data
114        left).
116    5.  Comprehensive information about what went wrong is now returned by
117        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
118        as the output vector has at least 2 elements. The offset of the start of
119        the failing character and a reason code are placed in the vector.
121    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
122        now returned is for the first byte of the failing character, instead of the
123        last byte inspected. This is an incompatible change, but I hope it is small
124        enough not to be a problem. It makes the returned offset consistent with
125        pcre_exec() and pcre_dfa_exec().
127    7.  pcretest now gives a text phrase as well as the error number when
128        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
129        failure, the offset and reason code are output.
131    8.  When \R was used with a maximizing quantifier it failed to skip backwards
132        over a \r\n pair if the subsequent match failed. Instead, it just skipped
133        back over a single character (\n). This seems wrong (because it treated the
134        two characters as a single entity when going forwards), conflicts with the
135        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
136        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
137        has been changed.
139    9.  Some internal refactoring has changed the processing so that the handling
140        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
141        time (the PCRE_DOTALL option was changed this way some time ago: version
142        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
143        which was always a bit of a fudge. It also means that there is one less
144        argument for the match() function, which reduces its stack requirements
145        slightly. This change also fixes an incompatibility with Perl: the pattern
146        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
148    10. More internal refactoring has drastically reduced the number of recursive
149        calls to match() for possessively repeated groups such as (abc)++ when
150        using pcre_exec().
152    11. While implementing 10, a number of bugs in the handling of groups were
153        discovered and fixed:
155        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
156        (a|)*(?1) gave a compile-time internal error.
157        ((a|)+)+  did not notice that the outer group could match an empty string.
158        (^a|^)+   was not marked as anchored.
159        (.*a|.*)+ was not marked as matching at start or after a newline.
161    12. Yet more internal refactoring has removed another argument from the match()
162        function. Special calls to this function are now indicated by setting a
163        value in a variable in the "match data" data block.
165    13. Be more explicit in pcre_study() instead of relying on "default" for
166        opcodes that mean there is no starting character; this means that when new
167        ones are added and accidentally left out of pcre_study(), testing should
168        pick them up.
170    14. The -s option of pcretest has been documented for ages as being an old
171        synonym of -m (show memory usage). I have changed it to mean "force study
172        for every regex", that is, assume /S for every regex. This is similar to -i
173        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
174        using it. It makes it easier to run collections of tests with and without
175        study enabled, and thereby test pcre_study() more easily. All the standard
176        tests are now run with and without -s (but some patterns can be marked as
177        "never study" - see 20 below).
179    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
180        restoration of the capturing data to the outer values was not happening
181        correctly.
183    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
184        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
185        pattern had matched an empty string, and so incorrectly returned a no
186        match.
188    17. There was optimizing code for the last branch of non-capturing parentheses,
189        and also for the obeyed branch of a conditional subexpression, which used
190        tail recursion to cut down on stack usage. Unfortunately, now that there is
191        the possibility of (*THEN) occurring in these branches, tail recursion is
192        no longer possible because the return has to be checked for (*THEN). These
193        two optimizations have therefore been removed. [But see 8.20/11 above.]
195    18. If a pattern containing \R was studied, it was assumed that \R always
196        matched two bytes, thus causing the minimum subject length to be
197        incorrectly computed because \R can also match just one byte.
199    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
200        was incorrectly computed.
202    20. If /S is present twice on a test pattern in pcretest input, it now
203        *disables* studying, thereby overriding the use of -s on the command line
204        (see 14 above). This is necessary for one or two tests to keep the output
205        identical in both cases.
207    21. When (*ACCEPT) was used in an assertion that matched an empty string and
208        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
210    22. When an atomic group that contained a capturing parenthesis was
211        successfully matched, but the branch in which it appeared failed, the
212        capturing was not being forgotten if a higher numbered group was later
213        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
214        group 1 to "a", when in fact it should be unset. This applied to multi-
215        branched capturing and non-capturing groups, repeated or not, and also to
216        positive assertions (capturing in negative assertions does not happen
217        in PCRE) and also to nested atomic groups.
219    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
220        subject after a captured substring, to make it easier to tell which of a
221        number of identical substrings has been captured.
223    24. The way atomic groups are processed by pcre_exec() has been changed so that
224        if they are repeated, backtracking one repetition now resets captured
225        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
226        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
227        "aaa". Previously, it would have been "a". As part of this code
228        refactoring, the way recursive calls are handled has also been changed.
230    25. If an assertion condition captured any substrings, they were not passed
231        back unless some other capturing happened later. For example, if
232        (?(?=(a))a) was matched against "a", no capturing was returned.
234    26. When studying a pattern that contained subroutine calls or assertions,
235        the code for finding the minimum length of a possible match was handling
236        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
237        group 1 called group 2 while simultaneously a separate group 2 called group
238        1). A stack overflow occurred in this case. I have fixed this by limiting
239        the recursion depth to 10.
241    27. Updated RunTest.bat in the distribution to the version supplied by Tom
242        Fortmann. This supports explicit test numbers on the command line, and has
243        argument validation and error reporting.
245    28. An instance of \X with an unlimited repeat could fail if at any point the
246        first character it looked at was a mark character.
248    29. Some minor code refactoring concerning Unicode properties and scripts
249        should reduce the stack requirement of match() slightly.
251    30. Added the '=' option to pcretest to check the setting of unused capturing
252        slots at the end of the pattern, which are documented as being -1, but are
253        not included in the return count.
255    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
256        compiled something random. Now it gives a compile-time error (as does
257        Perl).
259    32. A *MARK encountered during the processing of a positive assertion is now
260        recorded and passed back (compatible with Perl).
262    33. If --only-matching or --colour was set on a pcregrep call whose pattern
263        had alternative anchored branches, the search for a second match in a line
264        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
265        matched the line "0102" twice. The same bug affected patterns that started
266        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
267        twice.
269    34. Previously, PCRE did not allow quantification of assertions. However, Perl
270        does, and because of capturing effects, quantifying parenthesized
271        assertions may at times be useful. Quantifiers are now allowed for
272        parenthesized assertions.
274    35. A minor code tidy in pcre_compile() when checking options for \R usage.
276    36. \g was being checked for fancy things in a character class, when it should
277        just be a literal "g".
279    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
280        appearance of a nested POSIX class supersedes an apparent external class.
281        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
282        unescaped square brackets may also appear as part of class names. For
283        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
284        more like Perl. (But see 8.20/1 above.)
286    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
287        was because it thought it was \N{name}, which is not supported).
289    39. Add minix to OS list not supporting the -S option in pcretest.
291    40. PCRE tries to detect cases of infinite recursion at compile time, but it
292        cannot analyze patterns in sufficient detail to catch mutual recursions
293        such as ((?1))((?2)). There is now a runtime test that gives an error if a
294        subgroup is called recursively as a subpattern for a second time at the
295        same position in the subject string. In previous releases this might have
296        been caught by the recursion limit, or it might have run out of stack.
298    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
299        happen only once. PCRE was, however incorrectly giving a compile time error
300        "recursive call could loop indefinitely" because it cannot analyze the
301        pattern in sufficient detail. The compile time test no longer happens when
302        PCRE is compiling a conditional subpattern, but actual runaway loops are
303        now caught at runtime (see 40 above).
305    42. It seems that Perl allows any characters other than a closing parenthesis
306        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
307        has been changed to be the same.
309    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
310        as not to get warnings when autogen.sh is called. Also changed
311        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
313    44. To help people who use pcregrep to scan files containing exceedingly long
314        lines, the following changes have been made:
316        (a) The default value of the buffer size parameter has been increased from
317            8K to 20K. (The actual buffer used is three times this size.)
319        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
320            PCRE is built.
322        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
323            to be set at run time.
325        (d) Numerical values in pcregrep options can be followed by K or M, for
326            example --buffer-size=50K.
328        (e) If a line being scanned overflows pcregrep's buffer, an error is now
329            given and the return code is set to 2.
331    45. Add a pointer to the latest mark to the callout data block.
333    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
334        partial match of an empty string instead of no match. This was specific to
335        the use of ".".
337    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
338        complete match instead of a partial match. This bug was dependent on both
339        the PCRE_UTF8 and PCRE_DOTALL options being set.
341    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
342        starting byte set, because \b was not being ignored.
345    Version 8.12 15-Jan-2011
346    ------------------------
348    1.  Fixed some typos in the markup of the man pages, and wrote a script that
349        checks for such things as part of the documentation building process.
351    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
352        --match-limit and --recursion-limit options (added for 8.11). In
353        particular, this made one of the standard tests fail. (The integer value
354        went into the wrong half of a long int.)
356    3.  If the --colour option was given to pcregrep with -v (invert match), it
357        did strange things, either producing crazy output, or crashing. It should,
358        of course, ignore a request for colour when reporting lines that do not
359        match.
361    4.  Another pcregrep bug caused similar problems if --colour was specified with
362        -M (multiline) and the pattern match finished with a line ending.
364    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
365        matched in multiline mode, the following line was shown as part of the
366        match. This seems wrong, so I have changed it.
368    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
369        the check for further matches in the same line (so they could be coloured)
370        to overrun the end of the current line. If another match was found, it was
371        incorrectly shown (and then shown again when found in the next line).
373    7.  If pcregrep was compiled under Windows, there was a reference to the
374        function pcregrep_exit() before it was defined. I am assuming this was
375        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
376        reported by a user. I've moved the definition above the reference.
379    Version 8.11 10-Dec-2010
380    ------------------------
382    1.  (*THEN) was not working properly if there were untried alternatives prior
383        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
384        backtracked to try for "b" instead of moving to the next alternative branch
385        at the same level (in this case, to look for "c"). The Perl documentation
386        is clear that when (*THEN) is backtracked onto, it goes to the "next
387        alternative in the innermost enclosing group".
389    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
390        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
391        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
392        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
393        (*THEN).
395    3.  If \s appeared in a character class, it removed the VT character from
396        the class, even if it had been included by some previous item, for example
397        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
398        of \s, but is part of the POSIX "space" class.)
400    4.  A partial match never returns an empty string (because you can always
401        match an empty string at the end of the subject); however the checking for
402        an empty string was starting at the "start of match" point. This has been
403        changed to the "earliest inspected character" point, because the returned
404        data for a partial match starts at this character. This means that, for
405        example, /(?<=abc)def/ gives a partial match for the subject "abc"
406        (previously it gave "no match").
408    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
409        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
410        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
411        has an implication that the given string is incomplete (because a partial
412        match is preferred over a full match). For this reason, these items now
413        give a partial match in this situation. [Aside: previously, the one case
414        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
415        match rather than a full match, which was wrong by the old rules, but is
416        now correct.]
418    6.  There was a bug in the handling of #-introduced comments, recognized when
419        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
420        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
421        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
422        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
423        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
424        places in pcre_compile().
426    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
427        comments when looking ahead for named forward references to subpatterns,
428        the only newline sequence it recognized was NL. It now handles newlines
429        according to the set newline convention.
431    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
432        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
433        cater for a lack of strerror(). These oversights have been fixed.
435    9.  Added --match-limit and --recursion-limit to pcregrep.
437    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
439    11. When the -o option was used, pcregrep was setting a return code of 1, even
440        when matches were found, and --line-buffered was not being honoured.
442    12. Added an optional parentheses number to the -o and --only-matching options
443        of pcregrep.
445    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
446        can match an empty string. The code to do it in pcretest and pcredemo
447        needed fixing:
449        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
450            only one byte after an empty string match just before CRLF (this case
451            just got forgotten; "any" and "anycrlf" were OK).
453        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
454            mode when an empty string match preceded an ASCII character followed by
455            a non-ASCII character. (The code for advancing by one character rather
456            than one byte was nonsense.)
458        (c) The pcredemo.c sample program did not have any code at all to handle
459            the cases when CRLF is a valid newline sequence.
461    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
462        as a starting offset was within the subject string. There is now a new
463        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
464        negative or greater than the length of the string. In order to test this,
465        pcretest is extended to allow the setting of negative starting offsets.
467    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
468        starting offset points to the beginning of a UTF-8 character was
469        unnecessarily clumsy. I tidied it up.
471    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
472        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
474    17. Nobody had reported that the --include_dir option, which was added in
475        release 7.7 should have been called --include-dir (hyphen, not underscore)
476        for compatibility with GNU grep. I have changed it to --include-dir, but
477        left --include_dir as an undocumented synonym, and the same for
478        --exclude-dir, though that is not available in GNU grep, at least as of
479        release 2.5.4.
481    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
482        characters from a string of bytes) have been redefined so as not to use
483        loops, in order to improve performance in some environments. At the same
484        time, I abstracted some of the common code into auxiliary macros to save
485        repetition (this should not affect the compiled code).
487    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
488        compile-time error is now given if \c is not followed by an ASCII
489        character, that is, a byte less than 128. (In EBCDIC mode, the code is
490        different, and any byte value is allowed.)
492    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
493        START_OPTIMIZE option, which is now allowed at compile time - but just
494        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
495        to pcregrep and other applications that have no direct access to PCRE
496        options. The new /Y option in pcretest sets this option when calling
497        pcre_compile().
499    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
500        back references. Groups containing recursive back references were forced to
501        be atomic by that change, but in the case of named groups, the amount of
502        memory required was incorrectly computed, leading to "Failed: internal
503        error: code overflow". This has been fixed.
505    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
506        pcretest.c, to avoid build problems in some Borland environments.
509    Version 8.10 25-Jun-2010
510    ------------------------
512    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
513        THEN.
515    2.  (*ACCEPT) was not working when inside an atomic group.
517    3.  Inside a character class, \B is treated as a literal by default, but
518        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
519        causes the error). The code is unchanged, but I tidied the documentation.
521    4.  Inside a character class, PCRE always treated \R and \X as literals,
522        whereas Perl faults them if its -w option is set. I have changed PCRE so
523        that it faults them when PCRE_EXTRA is set.
525    5.  Added support for \N, which always matches any character other than
526        newline. (It is the same as "." when PCRE_DOTALL is not set.)
528    6.  When compiling pcregrep with newer versions of gcc which may have
529        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
530        declared with attribute warn_unused_result" were given. Just casting the
531        result to (void) does not stop the warnings; a more elaborate fudge is
532        needed. I've used a macro to implement this.
534    7.  Minor change to pcretest.c to avoid a compiler warning.
536    8.  Added four artifical Unicode properties to help with an option to make
537        \s etc use properties (see next item). The new properties are: Xan
538        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
540    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
541        use Unicode properties. (*UCP) at the start of a pattern can be used to set
542        this option. Modified pcretest to add /W to test this facility. Added
543        REG_UCP to make it available via the POSIX interface.
545    10. Added --line-buffered to pcregrep.
547    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
548        studied, and the match started with a letter with a code point greater than
549        127 whose first byte was different to the first byte of the other case of
550        the letter, the other case of this starting letter was not recognized
551        (#976).
553    12. If a pattern that was studied started with a repeated Unicode property
554        test, for example, \p{Nd}+, there was the theoretical possibility of
555        setting up an incorrect bitmap of starting bytes, but fortunately it could
556        not have actually happened in practice until change 8 above was made (it
557        added property types that matched character-matching opcodes).
559    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
560        possible starting bytes for non-anchored patterns.
562    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
563        \R, and also a number of cases that involve Unicode properties, both
564        explicit and implicit when PCRE_UCP is set.
566    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
567        input, it could crash or give wrong results if characters with values
568        greater than 0xc0 were present in the subject string. (Detail: it assumed
569        UTF-8 input when processing these items.)
571    16. Added a lot of (int) casts to avoid compiler warnings in systems where
572        size_t is 64-bit (#991).
574    17. Added a check for running out of memory when PCRE is compiled with
575        --disable-stack-for-recursion (#990).
577    18. If the last data line in a file for pcretest does not have a newline on
578        the end, a newline was missing in the output.
580    19. The default pcre_chartables.c file recognizes only ASCII characters (values
581        less than 128) in its various bitmaps. However, there is a facility for
582        generating tables according to the current locale when PCRE is compiled. It
583        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
584        characters, are recognized by isspace() and therefore were getting set in
585        these tables, and indeed these tables seem to approximate to ISO 8859. This
586        caused a problem in UTF-8 mode when pcre_study() was used to create a list
587        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
588        which of course cannot start UTF-8 characters. I have changed the code so
589        that only real ASCII characters (less than 128) and the correct starting
590        bytes for UTF-8 encodings are set for characters greater than 127 when in
591        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
592        altogether.)
594    20. Added the /T option to pcretest so as to be able to run tests with non-
595        standard character tables, thus making it possible to include the tests
596        used for 19 above in the standard set of tests.
598    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
599        reference to a subpattern the other side of a comment that contains an
600        opening parenthesis caused either an internal compiling error, or a
601        reference to the wrong subpattern.
604    Version 8.02 19-Mar-2010
605    ------------------------
607    1.  The Unicode data tables have been updated to Unicode 5.2.0.
609    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
610        configured.
612    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
613        original author of that file, following a query about its status.
615    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
616        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
618    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
619        quantifier applied to a forward-referencing subroutine call, could compile
620        incorrect code or give the error "internal error: previously-checked
621        referenced subpattern not found".
623    6.  Both MS Visual Studio and Symbian OS have problems with initializing
624        variables to point to external functions. For these systems, therefore,
625        pcre_malloc etc. are now initialized to local functions that call the
626        relevant global functions.
628    7.  There were two entries missing in the vectors called coptable and poptable
629        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
630        I've fixed the data, and added a kludgy way of testing at compile time that
631        the lengths are correct (equal to the number of opcodes).
633    8.  Following on from 7, I added a similar kludge to check the length of the
634        eint vector in pcreposix.c.
636    9.  Error texts for pcre_compile() are held as one long string to avoid too
637        much relocation at load time. To find a text, the string is searched,
638        counting zeros. There was no check for running off the end of the string,
639        which could happen if a new error number was added without updating the
640        string.
642    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
644    11. \K was not working if it appeared in an atomic group or in a group that
645        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
646        \K is "not well defined" if used in an assertion. PCRE now accepts it if
647        the assertion is positive, but not if it is negative.
649    12. Change 11 fortuitously reduced the size of the stack frame used in the
650        "match()" function of pcre_exec.c by one pointer. Forthcoming
651        implementation of support for (*MARK) will need an extra pointer on the
652        stack; I have reserved it now, so that the stack frame size does not
653        decrease.
655    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
656        item in branch that calls a recursion is a subroutine call - as in the
657        second branch in the above example - was incorrectly given the compile-
658        time error "recursive call could loop indefinitely" because pcre_compile()
659        was not correctly checking the subroutine for matching a non-empty string.
661    14. The checks for overrunning compiling workspace could trigger after an
662        overrun had occurred. This is a "should never occur" error, but it can be
663        triggered by pathological patterns such as hundreds of nested parentheses.
664        The checks now trigger 100 bytes before the end of the workspace.
666    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
669    Version 8.01 19-Jan-2010
670    ------------------------
672    1.  If a pattern contained a conditional subpattern with only one branch (in
673        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
674        computed the wrong minimum data length (which is of course zero for such
675        subpatterns). This could cause incorrect "no match" results.
677    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
678      the pattern is reset in the first branch, pcre_compile() failed with      the pattern is reset in the first branch, pcre_compile() failed with
679      "internal error: code overflow at offset...". This happened only when      "internal error: code overflow at offset...". This happened only when
680      the reset was to the original external option setting. (An optimization      the reset was to the original external option setting. (An optimization
681      abstracts leading options settings into an external setting, which was the      abstracts leading options settings into an external setting, which was the
682      cause of this.)      cause of this.)
684    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
685        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
686        assertion pattern did not match (meaning that the assertion was true), it
687        was incorrectly treated as false if the SKIP had been reached during the
688        matching. This also applied to assertions used as conditions.
690    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
691        assertion subpattern, including such a pattern used as a condition,
692        unpredictable results occurred, instead of the error return
695    5.  The C++ GlobalReplace function was not working like Perl for the special
696        situation when an empty string is matched. It now does the fancy magic
697        stuff that is necessary.
699    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
700        removed. (These were left over from very, very early versions of PCRE.)
702    7.  Some cosmetic changes to the code to make life easier when compiling it
703        as part of something else:
705        (a) Change DEBUG to PCRE_DEBUG.
707        (b) In pcre_compile(), rename the member of the "branch_chain" structure
708            called "current" as "current_branch", to prevent a collision with the
709            Linux macro when compiled as a kernel module.
711        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
712            prevent a collision with the Linux macro when compiled as a kernel
713            module.
715    8.  In pcre_compile() there are some checks for integer overflows that used to
716        cast potentially large values to (double). This has been changed to that
717        when building, a check for int64_t is made, and if it is found, it is used
718        instead, thus avoiding the use of floating point arithmetic. (There is no
719        other use of FP in PCRE.) If int64_t is not found, the fallback is to
720        double.
722    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
723        2005 (difference between two addresses compared to an unsigned value).
725    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
726        custom one, because of the following reported problem in Windows:
728          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
729              under Win32.
730          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
731              therefore missing the function definition.
732          - The compiler thus generates a "C" signature for the test function.
733          - The linker fails to find the "C" function.
734          - PCRE fails to configure if asked to do so against libbz2.
736    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
737        messages were output:
739          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
740          rerunning libtoolize, to keep the correct libtool macros in-tree.
741          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
743        I have done both of these things.
745    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
746        most of the time, it *can* run out if it is given a pattern that contains a
747        runaway infinite recursion. I updated the discussion in the pcrestack man
748        page.
750    13. Now that we have gone to the x.xx style of version numbers, the minor
751        version may start with zero. Using 08 or 09 is a bad idea because users
752        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
753        interpreted as invalid octal numbers. I've updated the previous comment in
754        configure.ac, and also added a check that gives an error if 08 or 09 are
755        used.
757    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
758        causing partial matching to fail when the end of the subject matched \W
759        in a UTF-8 pattern where \W was quantified with a minimum of 3.
761    15. There were some discrepancies between the declarations in pcre_internal.h
762        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
763        their definitions. The declarations used "const uschar *" and the
764        definitions used USPTR. Even though USPTR is normally defined as "const
765        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
766        reported that: "This difference in casting confuses some C++ compilers, for
767        example, SunCC recognizes above declarations as different functions and
768        generates broken code for hbpcre." I have changed the declarations to use
769        USPTR.
771    16. GNU libtool is named differently on some systems. The autogen.sh script now
772        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
773        (FreeBSD).
775    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
776        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
777        comment: "Figure out how to create a longlong from a string: strtoll and
778        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
779        instance, but it only takes 2 args instead of 3!"
781    18. A subtle bug concerned with back references has been fixed by a change of
782        specification, with a corresponding code fix. A pattern such as
783        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
784        refers, was giving matches when it shouldn't. For example, xa=xaaa would
785        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
786        same bug. Such groups have to be quantified to be useful, or contained
787        inside another quantified group. (If there's no repetition, the reference
788        can never match.) The problem arises because, having left the group and
789        moved on to the rest of the pattern, a later failure that backtracks into
790        the group uses the captured value from the final iteration of the group
791        rather than the correct earlier one. I have fixed this in PCRE by forcing
792        any group that contains a reference to itself to be an atomic group; that
793        is, there cannot be any backtracking into it once it has completed. This is
794        similar to recursive and subroutine calls.
797  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
798  ----------------------  ----------------------

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