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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.00 ??-???-??  Version 8.20
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.
12    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
13       substring, but while checking the failing first alternative, substring 1 is
14       temporarily captured. If the output vector supplied to pcre_exec() was not
15       big enough for this capture, the yield of the function was still zero
16       ("insufficient space for captured substrings"). This cannot be totally fixed
17       without adding another stack variable, which seems a lot of expense for a
18       edge case. However, I have improved the situation in cases such as
19       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
20       fewer than the maximum number of slots in the ovector have been set.
22    3. Related to (2) above: when there are more back references in a pattern than
23       slots in the output vector, pcre_exec() uses temporary memory during
24       matching, and copies in the captures as far as possible afterwards. It was
25       using the entire output vector, but this conflicts with the specification
26       that only 2/3 is used for passing back captured substrings. Now it uses only
27       the first 2/3, for compatibility. This is, of course, another edge case.
29    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
30       main code base, and can be used by building with --enable-jit.
33    Version 8.13 16-Aug-2011
34    ------------------------
36    1.  The Unicode data tables have been updated to Unicode 6.0.0.
38    2.  Two minor typos in pcre_internal.h have been fixed.
40    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
41        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
42        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
44    4.  There were a number of related bugs in the code for matching backrefences
45        caselessly in UTF-8 mode when codes for the characters concerned were
46        different numbers of bytes. For example, U+023A and U+2C65 are an upper
47        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
48        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
49        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
50        2-byte code at the end of the subject (it thought there wasn't enough data
51        left).
53    5.  Comprehensive information about what went wrong is now returned by
54        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
55        as the output vector has at least 2 elements. The offset of the start of
56        the failing character and a reason code are placed in the vector.
58    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
59        now returned is for the first byte of the failing character, instead of the
60        last byte inspected. This is an incompatible change, but I hope it is small
61        enough not to be a problem. It makes the returned offset consistent with
62        pcre_exec() and pcre_dfa_exec().
64    7.  pcretest now gives a text phrase as well as the error number when
65        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
66        failure, the offset and reason code are output.
68    8.  When \R was used with a maximizing quantifier it failed to skip backwards
69        over a \r\n pair if the subsequent match failed. Instead, it just skipped
70        back over a single character (\n). This seems wrong (because it treated the
71        two characters as a single entity when going forwards), conflicts with the
72        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
73        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
74        has been changed.
76    9.  Some internal refactoring has changed the processing so that the handling
77        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
78        time (the PCRE_DOTALL option was changed this way some time ago: version
79        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
80        which was always a bit of a fudge. It also means that there is one less
81        argument for the match() function, which reduces its stack requirements
82        slightly. This change also fixes an incompatibility with Perl: the pattern
83        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
85    10. More internal refactoring has drastically reduced the number of recursive
86        calls to match() for possessively repeated groups such as (abc)++ when
87        using pcre_exec().
89    11. While implementing 10, a number of bugs in the handling of groups were
90        discovered and fixed:
92        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
93        (a|)*(?1) gave a compile-time internal error.
94        ((a|)+)+  did not notice that the outer group could match an empty string.
95        (^a|^)+   was not marked as anchored.
96        (.*a|.*)+ was not marked as matching at start or after a newline.
98    12. Yet more internal refactoring has removed another argument from the match()
99        function. Special calls to this function are now indicated by setting a
100        value in a variable in the "match data" data block.
102    13. Be more explicit in pcre_study() instead of relying on "default" for
103        opcodes that mean there is no starting character; this means that when new
104        ones are added and accidentally left out of pcre_study(), testing should
105        pick them up.
107    14. The -s option of pcretest has been documented for ages as being an old
108        synonym of -m (show memory usage). I have changed it to mean "force study
109        for every regex", that is, assume /S for every regex. This is similar to -i
110        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
111        using it. It makes it easier to run collections of tests with and without
112        study enabled, and thereby test pcre_study() more easily. All the standard
113        tests are now run with and without -s (but some patterns can be marked as
114        "never study" - see 20 below).
116    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
117        restoration of the capturing data to the outer values was not happening
118        correctly.
120    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
121        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
122        pattern had matched an empty string, and so incorrectly returned a no
123        match.
125    17. There was optimizing code for the last branch of non-capturing parentheses,
126        and also for the obeyed branch of a conditional subexpression, which used
127        tail recursion to cut down on stack usage. Unfortunately, now that there is
128        the possibility of (*THEN) occurring in these branches, tail recursion is
129        no longer possible because the return has to be checked for (*THEN). These
130        two optimizations have therefore been removed.
132    18. If a pattern containing \R was studied, it was assumed that \R always
133        matched two bytes, thus causing the minimum subject length to be
134        incorrectly computed because \R can also match just one byte.
136    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
137        was incorrectly computed.
139    20. If /S is present twice on a test pattern in pcretest input, it now
140        *disables* studying, thereby overriding the use of -s on the command line
141        (see 14 above). This is necessary for one or two tests to keep the output
142        identical in both cases.
144    21. When (*ACCEPT) was used in an assertion that matched an empty string and
145        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
147    22. When an atomic group that contained a capturing parenthesis was
148        successfully matched, but the branch in which it appeared failed, the
149        capturing was not being forgotten if a higher numbered group was later
150        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
151        group 1 to "a", when in fact it should be unset. This applied to multi-
152        branched capturing and non-capturing groups, repeated or not, and also to
153        positive assertions (capturing in negative assertions does not happen
154        in PCRE) and also to nested atomic groups.
156    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
157        subject after a captured substring, to make it easier to tell which of a
158        number of identical substrings has been captured.
160    24. The way atomic groups are processed by pcre_exec() has been changed so that
161        if they are repeated, backtracking one repetition now resets captured
162        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
163        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
164        "aaa". Previously, it would have been "a". As part of this code
165        refactoring, the way recursive calls are handled has also been changed.
167    25. If an assertion condition captured any substrings, they were not passed
168        back unless some other capturing happened later. For example, if
169        (?(?=(a))a) was matched against "a", no capturing was returned.
171    26. When studying a pattern that contained subroutine calls or assertions,
172        the code for finding the minimum length of a possible match was handling
173        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
174        group 1 called group 2 while simultaneously a separate group 2 called group
175        1). A stack overflow occurred in this case. I have fixed this by limiting
176        the recursion depth to 10.
178    27. Updated RunTest.bat in the distribution to the version supplied by Tom
179        Fortmann. This supports explicit test numbers on the command line, and has
180        argument validation and error reporting.
182    28. An instance of \X with an unlimited repeat could fail if at any point the
183        first character it looked at was a mark character.
185    29. Some minor code refactoring concerning Unicode properties and scripts
186        should reduce the stack requirement of match() slightly.
188    30. Added the '=' option to pcretest to check the setting of unused capturing
189        slots at the end of the pattern, which are documented as being -1, but are
190        not included in the return count.
192    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
193        compiled something random. Now it gives a compile-time error (as does
194        Perl).
196    32. A *MARK encountered during the processing of a positive assertion is now
197        recorded and passed back (compatible with Perl).
199    33. If --only-matching or --colour was set on a pcregrep call whose pattern
200        had alternative anchored branches, the search for a second match in a line
201        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
202        matched the line "0102" twice. The same bug affected patterns that started
203        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
204        twice.
206    34. Previously, PCRE did not allow quantification of assertions. However, Perl
207        does, and because of capturing effects, quantifying parenthesized
208        assertions may at times be useful. Quantifiers are now allowed for
209        parenthesized assertions.
211    35. A minor code tidy in pcre_compile() when checking options for \R usage.
213    36. \g was being checked for fancy things in a character class, when it should
214        just be a literal "g".
216    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
217        appearance of a nested POSIX class supersedes an apparent external class.
218        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
219        unescaped square brackets may also appear as part of class names. For
220        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
221        more like Perl. (But see 8.20/1 above.)
223    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
224        was because it thought it was \N{name}, which is not supported).
226    39. Add minix to OS list not supporting the -S option in pcretest.
228    40. PCRE tries to detect cases of infinite recursion at compile time, but it
229        cannot analyze patterns in sufficient detail to catch mutual recursions
230        such as ((?1))((?2)). There is now a runtime test that gives an error if a
231        subgroup is called recursively as a subpattern for a second time at the
232        same position in the subject string. In previous releases this might have
233        been caught by the recursion limit, or it might have run out of stack.
235    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
236        happen only once. PCRE was, however incorrectly giving a compile time error
237        "recursive call could loop indefinitely" because it cannot analyze the
238        pattern in sufficient detail. The compile time test no longer happens when
239        PCRE is compiling a conditional subpattern, but actual runaway loops are
240        now caught at runtime (see 40 above).
242    42. It seems that Perl allows any characters other than a closing parenthesis
243        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
244        has been changed to be the same.
246    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
247        as not to get warnings when autogen.sh is called. Also changed
248        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
250    44. To help people who use pcregrep to scan files containing exceedingly long
251        lines, the following changes have been made:
253        (a) The default value of the buffer size parameter has been increased from
254            8K to 20K. (The actual buffer used is three times this size.)
256        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
257            PCRE is built.
259        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
260            to be set at run time.
262        (d) Numerical values in pcregrep options can be followed by K or M, for
263            example --buffer-size=50K.
265        (e) If a line being scanned overflows pcregrep's buffer, an error is now
266            given and the return code is set to 2.
268    45. Add a pointer to the latest mark to the callout data block.
270    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
271        partial match of an empty string instead of no match. This was specific to
272        the use of ".".
274    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
275        complete match instead of a partial match. This bug was dependent on both
276        the PCRE_UTF8 and PCRE_DOTALL options being set.
278    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
279        starting byte set, because \b was not being ignored.
282    Version 8.12 15-Jan-2011
283    ------------------------
285    1.  Fixed some typos in the markup of the man pages, and wrote a script that
286        checks for such things as part of the documentation building process.
288    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
289        --match-limit and --recursion-limit options (added for 8.11). In
290        particular, this made one of the standard tests fail. (The integer value
291        went into the wrong half of a long int.)
293    3.  If the --colour option was given to pcregrep with -v (invert match), it
294        did strange things, either producing crazy output, or crashing. It should,
295        of course, ignore a request for colour when reporting lines that do not
296        match.
298    4.  Another pcregrep bug caused similar problems if --colour was specified with
299        -M (multiline) and the pattern match finished with a line ending.
301    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
302        matched in multiline mode, the following line was shown as part of the
303        match. This seems wrong, so I have changed it.
305    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
306        the check for further matches in the same line (so they could be coloured)
307        to overrun the end of the current line. If another match was found, it was
308        incorrectly shown (and then shown again when found in the next line).
310    7.  If pcregrep was compiled under Windows, there was a reference to the
311        function pcregrep_exit() before it was defined. I am assuming this was
312        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
313        reported by a user. I've moved the definition above the reference.
316    Version 8.11 10-Dec-2010
317    ------------------------
319    1.  (*THEN) was not working properly if there were untried alternatives prior
320        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
321        backtracked to try for "b" instead of moving to the next alternative branch
322        at the same level (in this case, to look for "c"). The Perl documentation
323        is clear that when (*THEN) is backtracked onto, it goes to the "next
324        alternative in the innermost enclosing group".
326    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
327        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
328        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
329        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
330        (*THEN).
332    3.  If \s appeared in a character class, it removed the VT character from
333        the class, even if it had been included by some previous item, for example
334        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
335        of \s, but is part of the POSIX "space" class.)
337    4.  A partial match never returns an empty string (because you can always
338        match an empty string at the end of the subject); however the checking for
339        an empty string was starting at the "start of match" point. This has been
340        changed to the "earliest inspected character" point, because the returned
341        data for a partial match starts at this character. This means that, for
342        example, /(?<=abc)def/ gives a partial match for the subject "abc"
343        (previously it gave "no match").
345    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
346        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
347        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
348        has an implication that the given string is incomplete (because a partial
349        match is preferred over a full match). For this reason, these items now
350        give a partial match in this situation. [Aside: previously, the one case
351        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
352        match rather than a full match, which was wrong by the old rules, but is
353        now correct.]
355    6.  There was a bug in the handling of #-introduced comments, recognized when
356        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
357        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
358        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
359        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
360        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
361        places in pcre_compile().
363    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
364        comments when looking ahead for named forward references to subpatterns,
365        the only newline sequence it recognized was NL. It now handles newlines
366        according to the set newline convention.
368    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
369        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
370        cater for a lack of strerror(). These oversights have been fixed.
372    9.  Added --match-limit and --recursion-limit to pcregrep.
374    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
376    11. When the -o option was used, pcregrep was setting a return code of 1, even
377        when matches were found, and --line-buffered was not being honoured.
379    12. Added an optional parentheses number to the -o and --only-matching options
380        of pcregrep.
382    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
383        can match an empty string. The code to do it in pcretest and pcredemo
384        needed fixing:
386        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
387            only one byte after an empty string match just before CRLF (this case
388            just got forgotten; "any" and "anycrlf" were OK).
390        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
391            mode when an empty string match preceded an ASCII character followed by
392            a non-ASCII character. (The code for advancing by one character rather
393            than one byte was nonsense.)
395        (c) The pcredemo.c sample program did not have any code at all to handle
396            the cases when CRLF is a valid newline sequence.
398    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
399        as a starting offset was within the subject string. There is now a new
400        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
401        negative or greater than the length of the string. In order to test this,
402        pcretest is extended to allow the setting of negative starting offsets.
404    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
405        starting offset points to the beginning of a UTF-8 character was
406        unnecessarily clumsy. I tidied it up.
408    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
409        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
411    17. Nobody had reported that the --include_dir option, which was added in
412        release 7.7 should have been called --include-dir (hyphen, not underscore)
413        for compatibility with GNU grep. I have changed it to --include-dir, but
414        left --include_dir as an undocumented synonym, and the same for
415        --exclude-dir, though that is not available in GNU grep, at least as of
416        release 2.5.4.
418    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
419        characters from a string of bytes) have been redefined so as not to use
420        loops, in order to improve performance in some environments. At the same
421        time, I abstracted some of the common code into auxiliary macros to save
422        repetition (this should not affect the compiled code).
424    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
425        compile-time error is now given if \c is not followed by an ASCII
426        character, that is, a byte less than 128. (In EBCDIC mode, the code is
427        different, and any byte value is allowed.)
429    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
430        START_OPTIMIZE option, which is now allowed at compile time - but just
431        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
432        to pcregrep and other applications that have no direct access to PCRE
433        options. The new /Y option in pcretest sets this option when calling
434        pcre_compile().
436    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
437        back references. Groups containing recursive back references were forced to
438        be atomic by that change, but in the case of named groups, the amount of
439        memory required was incorrectly computed, leading to "Failed: internal
440        error: code overflow". This has been fixed.
442    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
443        pcretest.c, to avoid build problems in some Borland environments.
446    Version 8.10 25-Jun-2010
447    ------------------------
449    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
450        THEN.
452    2.  (*ACCEPT) was not working when inside an atomic group.
454    3.  Inside a character class, \B is treated as a literal by default, but
455        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
456        causes the error). The code is unchanged, but I tidied the documentation.
458    4.  Inside a character class, PCRE always treated \R and \X as literals,
459        whereas Perl faults them if its -w option is set. I have changed PCRE so
460        that it faults them when PCRE_EXTRA is set.
462    5.  Added support for \N, which always matches any character other than
463        newline. (It is the same as "." when PCRE_DOTALL is not set.)
465    6.  When compiling pcregrep with newer versions of gcc which may have
466        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
467        declared with attribute warn_unused_result" were given. Just casting the
468        result to (void) does not stop the warnings; a more elaborate fudge is
469        needed. I've used a macro to implement this.
471    7.  Minor change to pcretest.c to avoid a compiler warning.
473    8.  Added four artifical Unicode properties to help with an option to make
474        \s etc use properties (see next item). The new properties are: Xan
475        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
477    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
478        use Unicode properties. (*UCP) at the start of a pattern can be used to set
479        this option. Modified pcretest to add /W to test this facility. Added
480        REG_UCP to make it available via the POSIX interface.
482    10. Added --line-buffered to pcregrep.
484    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
485        studied, and the match started with a letter with a code point greater than
486        127 whose first byte was different to the first byte of the other case of
487        the letter, the other case of this starting letter was not recognized
488        (#976).
490    12. If a pattern that was studied started with a repeated Unicode property
491        test, for example, \p{Nd}+, there was the theoretical possibility of
492        setting up an incorrect bitmap of starting bytes, but fortunately it could
493        not have actually happened in practice until change 8 above was made (it
494        added property types that matched character-matching opcodes).
496    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
497        possible starting bytes for non-anchored patterns.
499    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
500        \R, and also a number of cases that involve Unicode properties, both
501        explicit and implicit when PCRE_UCP is set.
503    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
504        input, it could crash or give wrong results if characters with values
505        greater than 0xc0 were present in the subject string. (Detail: it assumed
506        UTF-8 input when processing these items.)
508    16. Added a lot of (int) casts to avoid compiler warnings in systems where
509        size_t is 64-bit (#991).
511    17. Added a check for running out of memory when PCRE is compiled with
512        --disable-stack-for-recursion (#990).
514    18. If the last data line in a file for pcretest does not have a newline on
515        the end, a newline was missing in the output.
517    19. The default pcre_chartables.c file recognizes only ASCII characters (values
518        less than 128) in its various bitmaps. However, there is a facility for
519        generating tables according to the current locale when PCRE is compiled. It
520        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
521        characters, are recognized by isspace() and therefore were getting set in
522        these tables, and indeed these tables seem to approximate to ISO 8859. This
523        caused a problem in UTF-8 mode when pcre_study() was used to create a list
524        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
525        which of course cannot start UTF-8 characters. I have changed the code so
526        that only real ASCII characters (less than 128) and the correct starting
527        bytes for UTF-8 encodings are set for characters greater than 127 when in
528        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
529        altogether.)
531    20. Added the /T option to pcretest so as to be able to run tests with non-
532        standard character tables, thus making it possible to include the tests
533        used for 19 above in the standard set of tests.
535    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
536        reference to a subpattern the other side of a comment that contains an
537        opening parenthesis caused either an internal compiling error, or a
538        reference to the wrong subpattern.
541    Version 8.02 19-Mar-2010
542    ------------------------
544    1.  The Unicode data tables have been updated to Unicode 5.2.0.
546    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
547        configured.
549    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
550        original author of that file, following a query about its status.
552    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
553        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
555    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
556        quantifier applied to a forward-referencing subroutine call, could compile
557        incorrect code or give the error "internal error: previously-checked
558        referenced subpattern not found".
560    6.  Both MS Visual Studio and Symbian OS have problems with initializing
561        variables to point to external functions. For these systems, therefore,
562        pcre_malloc etc. are now initialized to local functions that call the
563        relevant global functions.
565    7.  There were two entries missing in the vectors called coptable and poptable
566        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
567        I've fixed the data, and added a kludgy way of testing at compile time that
568        the lengths are correct (equal to the number of opcodes).
570    8.  Following on from 7, I added a similar kludge to check the length of the
571        eint vector in pcreposix.c.
573    9.  Error texts for pcre_compile() are held as one long string to avoid too
574        much relocation at load time. To find a text, the string is searched,
575        counting zeros. There was no check for running off the end of the string,
576        which could happen if a new error number was added without updating the
577        string.
579    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
581    11. \K was not working if it appeared in an atomic group or in a group that
582        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
583        \K is "not well defined" if used in an assertion. PCRE now accepts it if
584        the assertion is positive, but not if it is negative.
586    12. Change 11 fortuitously reduced the size of the stack frame used in the
587        "match()" function of pcre_exec.c by one pointer. Forthcoming
588        implementation of support for (*MARK) will need an extra pointer on the
589        stack; I have reserved it now, so that the stack frame size does not
590        decrease.
592    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
593        item in branch that calls a recursion is a subroutine call - as in the
594        second branch in the above example - was incorrectly given the compile-
595        time error "recursive call could loop indefinitely" because pcre_compile()
596        was not correctly checking the subroutine for matching a non-empty string.
598    14. The checks for overrunning compiling workspace could trigger after an
599        overrun had occurred. This is a "should never occur" error, but it can be
600        triggered by pathological patterns such as hundreds of nested parentheses.
601        The checks now trigger 100 bytes before the end of the workspace.
603    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
606    Version 8.01 19-Jan-2010
607    ------------------------
609    1.  If a pattern contained a conditional subpattern with only one branch (in
610        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
611        computed the wrong minimum data length (which is of course zero for such
612        subpatterns). This could cause incorrect "no match" results.
614    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
615        the pattern is reset in the first branch, pcre_compile() failed with
616        "internal error: code overflow at offset...". This happened only when
617        the reset was to the original external option setting. (An optimization
618        abstracts leading options settings into an external setting, which was the
619        cause of this.)
621    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
622        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
623        assertion pattern did not match (meaning that the assertion was true), it
624        was incorrectly treated as false if the SKIP had been reached during the
625        matching. This also applied to assertions used as conditions.
627    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
628        assertion subpattern, including such a pattern used as a condition,
629        unpredictable results occurred, instead of the error return
632    5.  The C++ GlobalReplace function was not working like Perl for the special
633        situation when an empty string is matched. It now does the fancy magic
634        stuff that is necessary.
636    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
637        removed. (These were left over from very, very early versions of PCRE.)
639    7.  Some cosmetic changes to the code to make life easier when compiling it
640        as part of something else:
642        (a) Change DEBUG to PCRE_DEBUG.
644        (b) In pcre_compile(), rename the member of the "branch_chain" structure
645            called "current" as "current_branch", to prevent a collision with the
646            Linux macro when compiled as a kernel module.
648        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
649            prevent a collision with the Linux macro when compiled as a kernel
650            module.
652    8.  In pcre_compile() there are some checks for integer overflows that used to
653        cast potentially large values to (double). This has been changed to that
654        when building, a check for int64_t is made, and if it is found, it is used
655        instead, thus avoiding the use of floating point arithmetic. (There is no
656        other use of FP in PCRE.) If int64_t is not found, the fallback is to
657        double.
659    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
660        2005 (difference between two addresses compared to an unsigned value).
662    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
663        custom one, because of the following reported problem in Windows:
665          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
666              under Win32.
667          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
668              therefore missing the function definition.
669          - The compiler thus generates a "C" signature for the test function.
670          - The linker fails to find the "C" function.
671          - PCRE fails to configure if asked to do so against libbz2.
673    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
674        messages were output:
676          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
677          rerunning libtoolize, to keep the correct libtool macros in-tree.
678          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
680        I have done both of these things.
682    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
683        most of the time, it *can* run out if it is given a pattern that contains a
684        runaway infinite recursion. I updated the discussion in the pcrestack man
685        page.
687    13. Now that we have gone to the x.xx style of version numbers, the minor
688        version may start with zero. Using 08 or 09 is a bad idea because users
689        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
690        interpreted as invalid octal numbers. I've updated the previous comment in
691        configure.ac, and also added a check that gives an error if 08 or 09 are
692        used.
694    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
695        causing partial matching to fail when the end of the subject matched \W
696        in a UTF-8 pattern where \W was quantified with a minimum of 3.
698    15. There were some discrepancies between the declarations in pcre_internal.h
699        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
700        their definitions. The declarations used "const uschar *" and the
701        definitions used USPTR. Even though USPTR is normally defined as "const
702        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
703        reported that: "This difference in casting confuses some C++ compilers, for
704        example, SunCC recognizes above declarations as different functions and
705        generates broken code for hbpcre." I have changed the declarations to use
706        USPTR.
708    16. GNU libtool is named differently on some systems. The autogen.sh script now
709        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
710        (FreeBSD).
712    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
713        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
714        comment: "Figure out how to create a longlong from a string: strtoll and
715        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
716        instance, but it only takes 2 args instead of 3!"
718    18. A subtle bug concerned with back references has been fixed by a change of
719        specification, with a corresponding code fix. A pattern such as
720        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
721        refers, was giving matches when it shouldn't. For example, xa=xaaa would
722        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
723        same bug. Such groups have to be quantified to be useful, or contained
724        inside another quantified group. (If there's no repetition, the reference
725        can never match.) The problem arises because, having left the group and
726        moved on to the rest of the pattern, a later failure that backtracks into
727        the group uses the captured value from the final iteration of the group
728        rather than the correct earlier one. I have fixed this in PCRE by forcing
729        any group that contains a reference to itself to be an atomic group; that
730        is, there cannot be any backtracking into it once it has completed. This is
731        similar to recursive and subroutine calls.
734    Version 8.00 19-Oct-09
735  ----------------------  ----------------------
737  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
738      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
739      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
740      error.      error.
742  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
743      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
744      in a Windows environment.      in a Windows environment.
746  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
747      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
748      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
749      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
750      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
751      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
752      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
754  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
755      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
756      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
757      the old behaviour.      the old behaviour.
759  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
760      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
761      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
762      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
764    6.  No libpcreposix.pc file was created for pkg-config; there was just
765        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
767    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
768        when UCP support is not needed, by modifying the Python script that
769        generates it from Unicode data files. This should not matter if the module
770        is correctly used as a library, but I received one complaint about 50K of
771        unwanted data. My guess is that the person linked everything into his
772        program rather than using a library. Anyway, it does no harm.
774    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
775        was a minimum greater than 1 for a wide character in a possessive
776        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
777        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
778        character. Chaos in the form of incorrect output or a compiling loop could
779        result.
781    9.  The restrictions on what a pattern can contain when partial matching is
782        requested for pcre_exec() have been removed. All patterns can now be
783        partially matched by this function. In addition, if there are at least two
784        slots in the offset vector, the offset of the earliest inspected character
785        for the match and the offset of the end of the subject are set in them when
786        PCRE_ERROR_PARTIAL is returned.
788    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
789        synonymous with PCRE_PARTIAL, for backwards compatibility, and
790        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
791        and may be more useful for multi-segment matching.
793    11. Partial matching with pcre_exec() is now more intuitive. A partial match
794        used to be given if ever the end of the subject was reached; now it is
795        given only if matching could not proceed because another character was
796        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
797        string "Z", which now yields "no match" instead of "partial match". In the
798        case of pcre_dfa_exec(), "no match" is given if every matching path for the
799        final character ended with (*FAIL).
801    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
802        if the pattern had a "must contain" character that was already found in the
803        earlier partial match, unless partial matching was again requested. For
804        example, with the pattern /dog.(body)?/, the "must contain" character is
805        "g". If the first part-match was for the string "dog", restarting with
806        "sbody" failed. This bug has been fixed.
808    13. The string returned by pcre_dfa_exec() after a partial match has been
809        changed so that it starts at the first inspected character rather than the
810        first character of the match. This makes a difference only if the pattern
811        starts with a lookbehind assertion or \b or \B (\K is not supported by
812        pcre_dfa_exec()). It's an incompatible change, but it makes the two
813        matching functions compatible, and I think it's the right thing to do.
815    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
816        so that the demonstration program is easily available in environments where
817        PCRE has not been installed from source.
819    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
820        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
821        library.
823    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
824        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
825        is not the first non-POSIX option to be added. Clearly some people find
826        these options useful.
828    17. If a caller to the POSIX matching function regexec() passes a non-zero
829        value for nmatch with a NULL value for pmatch, the value of
830        nmatch is forced to zero.
832    18. RunGrepTest did not have a test for the availability of the -u option of
833        the diff command, as RunTest does. It now checks in the same way as
834        RunTest, and also checks for the -b option.
836    19. If an odd number of negated classes containing just a single character
837        interposed, within parentheses, between a forward reference to a named
838        subpattern and the definition of the subpattern, compilation crashed with
839        an internal error, complaining that it could not find the referenced
840        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
841        [The bug was that it was starting one character too far in when skipping
842        over the character class, thus treating the ] as data rather than
843        terminating the class. This meant it could skip too much.]
845    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
846        /g option in pcretest when the pattern contains \K, which makes it possible
847        to have an empty string match not at the start, even when the pattern is
848        anchored. Updated pcretest and pcredemo to use this option.
850    21. If the maximum number of capturing subpatterns in a recursion was greater
851        than the maximum at the outer level, the higher number was returned, but
852        with unset values at the outer level. The correct (outer level) value is
853        now given.
855    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
856        PCRE did not set those parentheses (unlike Perl). I have now found a way to
857        make it do so. The string so far is captured, making this feature
858        compatible with Perl.
860    23. The tests have been re-organized, adding tests 11 and 12, to make it
861        possible to check the Perl 5.10 features against Perl 5.10.
863    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
864        pattern matches a fixed length string. PCRE did not allow this; now it
865        does. Neither allows recursion.
867    25. I finally figured out how to implement a request to provide the minimum
868        length of subject string that was needed in order to match a given pattern.
869        (It was back references and recursion that I had previously got hung up
870        on.) This code has now been added to pcre_study(); it finds a lower bound
871        to the length of subject needed. It is not necessarily the greatest lower
872        bound, but using it to avoid searching strings that are too short does give
873        some useful speed-ups. The value is available to calling programs via
874        pcre_fullinfo().
876    26. While implementing 25, I discovered to my embarrassment that pcretest had
877        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
878        study optimizations had never been tested with that matching function.
879        Oops. What is worse, even when it was passed study data, there was a bug in
880        pcre_dfa_exec() that meant it never actually used it. Double oops. There
881        were also very few tests of studied patterns with pcre_dfa_exec().
883    27. If (?| is used to create subpatterns with duplicate numbers, they are now
884        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
885        on the other side of the coin, they are no longer allowed to have different
886        names, because these cannot be distinguished in PCRE, and this has caused
887        confusion. (This is a difference from Perl.)
889    28. When duplicate subpattern names are present (necessarily with different
890        numbers, as required by 27 above), and a test is made by name in a
891        conditional pattern, either for a subpattern having been matched, or for
892        recursion in such a pattern, all the associated numbered subpatterns are
893        tested, and the overall condition is true if the condition is true for any
894        one of them. This is the way Perl works, and is also more like the way
895        testing by number works.
898  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
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