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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  Version 8.20 12-Sep-2011
5    ------------------------
7    1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8       a POSIX class. After further experiments with Perl, which convinced me that
9       Perl has bugs and confusions, a closing square bracket is no longer allowed
10       in a POSIX name. This bug also affected patterns with classes that started
11       with full stops.
13    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
14       substring, but while checking the failing first alternative, substring 1 is
15       temporarily captured. If the output vector supplied to pcre_exec() was not
16       big enough for this capture, the yield of the function was still zero
17       ("insufficient space for captured substrings"). This cannot be totally fixed
18       without adding another stack variable, which seems a lot of expense for a
19       edge case. However, I have improved the situation in cases such as
20       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
21       fewer than the maximum number of slots in the ovector have been set.
23    3. Related to (2) above: when there are more back references in a pattern than
24       slots in the output vector, pcre_exec() uses temporary memory during
25       matching, and copies in the captures as far as possible afterwards. It was
26       using the entire output vector, but this conflicts with the specification
27       that only 2/3 is used for passing back captured substrings. Now it uses only
28       the first 2/3, for compatibility. This is, of course, another edge case.
30    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
31       main code base, and can be used by building with --enable-jit. When this is
32       done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
33       runtime --no-jit option is given.
35    5. When the number of matches in a pcre_dfa_exec() run exactly filled the
36       ovector, the return from the function was zero, implying that there were
37       other matches that did not fit. The correct "exactly full" value is now
38       returned.
40    6. If a subpattern that was called recursively or as a subroutine contained
41       (*PRUNE) or any other control that caused it to give a non-standard return,
42       invalid errors such as "Error -26 (nested recursion at the same subject
43       position)" or even infinite loops could occur.
45    7. If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
46       computing the minimum length on reaching *ACCEPT, and so ended up with the
47       wrong value of 1 rather than 0. Further investigation indicates that
48       computing a minimum subject length in the presence of *ACCEPT is difficult
49       (think back references, subroutine calls), and so I have changed the code so
50       that no minimum is registered for a pattern that contains *ACCEPT.
53    Version 8.13 16-Aug-2011
54    ------------------------
56    1.  The Unicode data tables have been updated to Unicode 6.0.0.
58    2.  Two minor typos in pcre_internal.h have been fixed.
60    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
61        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
62        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
64    4.  There were a number of related bugs in the code for matching backrefences
65        caselessly in UTF-8 mode when codes for the characters concerned were
66        different numbers of bytes. For example, U+023A and U+2C65 are an upper
67        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
68        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
69        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
70        2-byte code at the end of the subject (it thought there wasn't enough data
71        left).
73    5.  Comprehensive information about what went wrong is now returned by
74        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
75        as the output vector has at least 2 elements. The offset of the start of
76        the failing character and a reason code are placed in the vector.
78    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
79        now returned is for the first byte of the failing character, instead of the
80        last byte inspected. This is an incompatible change, but I hope it is small
81        enough not to be a problem. It makes the returned offset consistent with
82        pcre_exec() and pcre_dfa_exec().
84    7.  pcretest now gives a text phrase as well as the error number when
85        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
86        failure, the offset and reason code are output.
88    8.  When \R was used with a maximizing quantifier it failed to skip backwards
89        over a \r\n pair if the subsequent match failed. Instead, it just skipped
90        back over a single character (\n). This seems wrong (because it treated the
91        two characters as a single entity when going forwards), conflicts with the
92        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
93        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
94        has been changed.
96    9.  Some internal refactoring has changed the processing so that the handling
97        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
98        time (the PCRE_DOTALL option was changed this way some time ago: version
99        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
100        which was always a bit of a fudge. It also means that there is one less
101        argument for the match() function, which reduces its stack requirements
102        slightly. This change also fixes an incompatibility with Perl: the pattern
103        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
105    10. More internal refactoring has drastically reduced the number of recursive
106        calls to match() for possessively repeated groups such as (abc)++ when
107        using pcre_exec().
109    11. While implementing 10, a number of bugs in the handling of groups were
110        discovered and fixed:
112        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
113        (a|)*(?1) gave a compile-time internal error.
114        ((a|)+)+  did not notice that the outer group could match an empty string.
115        (^a|^)+   was not marked as anchored.
116        (.*a|.*)+ was not marked as matching at start or after a newline.
118    12. Yet more internal refactoring has removed another argument from the match()
119        function. Special calls to this function are now indicated by setting a
120        value in a variable in the "match data" data block.
122    13. Be more explicit in pcre_study() instead of relying on "default" for
123        opcodes that mean there is no starting character; this means that when new
124        ones are added and accidentally left out of pcre_study(), testing should
125        pick them up.
127    14. The -s option of pcretest has been documented for ages as being an old
128        synonym of -m (show memory usage). I have changed it to mean "force study
129        for every regex", that is, assume /S for every regex. This is similar to -i
130        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
131        using it. It makes it easier to run collections of tests with and without
132        study enabled, and thereby test pcre_study() more easily. All the standard
133        tests are now run with and without -s (but some patterns can be marked as
134        "never study" - see 20 below).
136    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
137        restoration of the capturing data to the outer values was not happening
138        correctly.
140    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
141        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
142        pattern had matched an empty string, and so incorrectly returned a no
143        match.
145    17. There was optimizing code for the last branch of non-capturing parentheses,
146        and also for the obeyed branch of a conditional subexpression, which used
147        tail recursion to cut down on stack usage. Unfortunately, now that there is
148        the possibility of (*THEN) occurring in these branches, tail recursion is
149        no longer possible because the return has to be checked for (*THEN). These
150        two optimizations have therefore been removed.
152    18. If a pattern containing \R was studied, it was assumed that \R always
153        matched two bytes, thus causing the minimum subject length to be
154        incorrectly computed because \R can also match just one byte.
156    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
157        was incorrectly computed.
159    20. If /S is present twice on a test pattern in pcretest input, it now
160        *disables* studying, thereby overriding the use of -s on the command line
161        (see 14 above). This is necessary for one or two tests to keep the output
162        identical in both cases.
164    21. When (*ACCEPT) was used in an assertion that matched an empty string and
165        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
167    22. When an atomic group that contained a capturing parenthesis was
168        successfully matched, but the branch in which it appeared failed, the
169        capturing was not being forgotten if a higher numbered group was later
170        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
171        group 1 to "a", when in fact it should be unset. This applied to multi-
172        branched capturing and non-capturing groups, repeated or not, and also to
173        positive assertions (capturing in negative assertions does not happen
174        in PCRE) and also to nested atomic groups.
176    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
177        subject after a captured substring, to make it easier to tell which of a
178        number of identical substrings has been captured.
180    24. The way atomic groups are processed by pcre_exec() has been changed so that
181        if they are repeated, backtracking one repetition now resets captured
182        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
183        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
184        "aaa". Previously, it would have been "a". As part of this code
185        refactoring, the way recursive calls are handled has also been changed.
187    25. If an assertion condition captured any substrings, they were not passed
188        back unless some other capturing happened later. For example, if
189        (?(?=(a))a) was matched against "a", no capturing was returned.
191    26. When studying a pattern that contained subroutine calls or assertions,
192        the code for finding the minimum length of a possible match was handling
193        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
194        group 1 called group 2 while simultaneously a separate group 2 called group
195        1). A stack overflow occurred in this case. I have fixed this by limiting
196        the recursion depth to 10.
198    27. Updated RunTest.bat in the distribution to the version supplied by Tom
199        Fortmann. This supports explicit test numbers on the command line, and has
200        argument validation and error reporting.
202    28. An instance of \X with an unlimited repeat could fail if at any point the
203        first character it looked at was a mark character.
205    29. Some minor code refactoring concerning Unicode properties and scripts
206        should reduce the stack requirement of match() slightly.
208    30. Added the '=' option to pcretest to check the setting of unused capturing
209        slots at the end of the pattern, which are documented as being -1, but are
210        not included in the return count.
212    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
213        compiled something random. Now it gives a compile-time error (as does
214        Perl).
216    32. A *MARK encountered during the processing of a positive assertion is now
217        recorded and passed back (compatible with Perl).
219    33. If --only-matching or --colour was set on a pcregrep call whose pattern
220        had alternative anchored branches, the search for a second match in a line
221        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
222        matched the line "0102" twice. The same bug affected patterns that started
223        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
224        twice.
226    34. Previously, PCRE did not allow quantification of assertions. However, Perl
227        does, and because of capturing effects, quantifying parenthesized
228        assertions may at times be useful. Quantifiers are now allowed for
229        parenthesized assertions.
231    35. A minor code tidy in pcre_compile() when checking options for \R usage.
233    36. \g was being checked for fancy things in a character class, when it should
234        just be a literal "g".
236    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
237        appearance of a nested POSIX class supersedes an apparent external class.
238        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
239        unescaped square brackets may also appear as part of class names. For
240        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
241        more like Perl. (But see 8.20/1 above.)
243    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
244        was because it thought it was \N{name}, which is not supported).
246    39. Add minix to OS list not supporting the -S option in pcretest.
248    40. PCRE tries to detect cases of infinite recursion at compile time, but it
249        cannot analyze patterns in sufficient detail to catch mutual recursions
250        such as ((?1))((?2)). There is now a runtime test that gives an error if a
251        subgroup is called recursively as a subpattern for a second time at the
252        same position in the subject string. In previous releases this might have
253        been caught by the recursion limit, or it might have run out of stack.
255    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
256        happen only once. PCRE was, however incorrectly giving a compile time error
257        "recursive call could loop indefinitely" because it cannot analyze the
258        pattern in sufficient detail. The compile time test no longer happens when
259        PCRE is compiling a conditional subpattern, but actual runaway loops are
260        now caught at runtime (see 40 above).
262    42. It seems that Perl allows any characters other than a closing parenthesis
263        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
264        has been changed to be the same.
266    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
267        as not to get warnings when autogen.sh is called. Also changed
268        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
270    44. To help people who use pcregrep to scan files containing exceedingly long
271        lines, the following changes have been made:
273        (a) The default value of the buffer size parameter has been increased from
274            8K to 20K. (The actual buffer used is three times this size.)
276        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
277            PCRE is built.
279        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
280            to be set at run time.
282        (d) Numerical values in pcregrep options can be followed by K or M, for
283            example --buffer-size=50K.
285        (e) If a line being scanned overflows pcregrep's buffer, an error is now
286            given and the return code is set to 2.
288    45. Add a pointer to the latest mark to the callout data block.
290    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
291        partial match of an empty string instead of no match. This was specific to
292        the use of ".".
294    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
295        complete match instead of a partial match. This bug was dependent on both
296        the PCRE_UTF8 and PCRE_DOTALL options being set.
298    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
299        starting byte set, because \b was not being ignored.
302    Version 8.12 15-Jan-2011
303    ------------------------
305    1.  Fixed some typos in the markup of the man pages, and wrote a script that
306        checks for such things as part of the documentation building process.
308    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
309        --match-limit and --recursion-limit options (added for 8.11). In
310        particular, this made one of the standard tests fail. (The integer value
311        went into the wrong half of a long int.)
313    3.  If the --colour option was given to pcregrep with -v (invert match), it
314        did strange things, either producing crazy output, or crashing. It should,
315        of course, ignore a request for colour when reporting lines that do not
316        match.
318    4.  Another pcregrep bug caused similar problems if --colour was specified with
319        -M (multiline) and the pattern match finished with a line ending.
321    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
322        matched in multiline mode, the following line was shown as part of the
323        match. This seems wrong, so I have changed it.
325    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
326        the check for further matches in the same line (so they could be coloured)
327        to overrun the end of the current line. If another match was found, it was
328        incorrectly shown (and then shown again when found in the next line).
330    7.  If pcregrep was compiled under Windows, there was a reference to the
331        function pcregrep_exit() before it was defined. I am assuming this was
332        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
333        reported by a user. I've moved the definition above the reference.
336    Version 8.11 10-Dec-2010
337    ------------------------
339    1.  (*THEN) was not working properly if there were untried alternatives prior
340        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
341        backtracked to try for "b" instead of moving to the next alternative branch
342        at the same level (in this case, to look for "c"). The Perl documentation
343        is clear that when (*THEN) is backtracked onto, it goes to the "next
344        alternative in the innermost enclosing group".
346    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
347        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
348        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
349        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
350        (*THEN).
352    3.  If \s appeared in a character class, it removed the VT character from
353        the class, even if it had been included by some previous item, for example
354        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
355        of \s, but is part of the POSIX "space" class.)
357    4.  A partial match never returns an empty string (because you can always
358        match an empty string at the end of the subject); however the checking for
359        an empty string was starting at the "start of match" point. This has been
360        changed to the "earliest inspected character" point, because the returned
361        data for a partial match starts at this character. This means that, for
362        example, /(?<=abc)def/ gives a partial match for the subject "abc"
363        (previously it gave "no match").
365    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
366        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
367        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
368        has an implication that the given string is incomplete (because a partial
369        match is preferred over a full match). For this reason, these items now
370        give a partial match in this situation. [Aside: previously, the one case
371        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
372        match rather than a full match, which was wrong by the old rules, but is
373        now correct.]
375    6.  There was a bug in the handling of #-introduced comments, recognized when
376        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
377        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
378        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
379        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
380        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
381        places in pcre_compile().
383    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
384        comments when looking ahead for named forward references to subpatterns,
385        the only newline sequence it recognized was NL. It now handles newlines
386        according to the set newline convention.
388    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
389        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
390        cater for a lack of strerror(). These oversights have been fixed.
392    9.  Added --match-limit and --recursion-limit to pcregrep.
394    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
396    11. When the -o option was used, pcregrep was setting a return code of 1, even
397        when matches were found, and --line-buffered was not being honoured.
399    12. Added an optional parentheses number to the -o and --only-matching options
400        of pcregrep.
402    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
403        can match an empty string. The code to do it in pcretest and pcredemo
404        needed fixing:
406        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
407            only one byte after an empty string match just before CRLF (this case
408            just got forgotten; "any" and "anycrlf" were OK).
410        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
411            mode when an empty string match preceded an ASCII character followed by
412            a non-ASCII character. (The code for advancing by one character rather
413            than one byte was nonsense.)
415        (c) The pcredemo.c sample program did not have any code at all to handle
416            the cases when CRLF is a valid newline sequence.
418    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
419        as a starting offset was within the subject string. There is now a new
420        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
421        negative or greater than the length of the string. In order to test this,
422        pcretest is extended to allow the setting of negative starting offsets.
424    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
425        starting offset points to the beginning of a UTF-8 character was
426        unnecessarily clumsy. I tidied it up.
428    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
429        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
431    17. Nobody had reported that the --include_dir option, which was added in
432        release 7.7 should have been called --include-dir (hyphen, not underscore)
433        for compatibility with GNU grep. I have changed it to --include-dir, but
434        left --include_dir as an undocumented synonym, and the same for
435        --exclude-dir, though that is not available in GNU grep, at least as of
436        release 2.5.4.
438    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
439        characters from a string of bytes) have been redefined so as not to use
440        loops, in order to improve performance in some environments. At the same
441        time, I abstracted some of the common code into auxiliary macros to save
442        repetition (this should not affect the compiled code).
444    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
445        compile-time error is now given if \c is not followed by an ASCII
446        character, that is, a byte less than 128. (In EBCDIC mode, the code is
447        different, and any byte value is allowed.)
449    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
450        START_OPTIMIZE option, which is now allowed at compile time - but just
451        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
452        to pcregrep and other applications that have no direct access to PCRE
453        options. The new /Y option in pcretest sets this option when calling
454        pcre_compile().
456    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
457        back references. Groups containing recursive back references were forced to
458        be atomic by that change, but in the case of named groups, the amount of
459        memory required was incorrectly computed, leading to "Failed: internal
460        error: code overflow". This has been fixed.
462    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
463        pcretest.c, to avoid build problems in some Borland environments.
466    Version 8.10 25-Jun-2010
467    ------------------------
469    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
470        THEN.
472    2.  (*ACCEPT) was not working when inside an atomic group.
474    3.  Inside a character class, \B is treated as a literal by default, but
475        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
476        causes the error). The code is unchanged, but I tidied the documentation.
478    4.  Inside a character class, PCRE always treated \R and \X as literals,
479        whereas Perl faults them if its -w option is set. I have changed PCRE so
480        that it faults them when PCRE_EXTRA is set.
482    5.  Added support for \N, which always matches any character other than
483        newline. (It is the same as "." when PCRE_DOTALL is not set.)
485    6.  When compiling pcregrep with newer versions of gcc which may have
486        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
487        declared with attribute warn_unused_result" were given. Just casting the
488        result to (void) does not stop the warnings; a more elaborate fudge is
489        needed. I've used a macro to implement this.
491    7.  Minor change to pcretest.c to avoid a compiler warning.
493    8.  Added four artifical Unicode properties to help with an option to make
494        \s etc use properties (see next item). The new properties are: Xan
495        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
497    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
498        use Unicode properties. (*UCP) at the start of a pattern can be used to set
499        this option. Modified pcretest to add /W to test this facility. Added
500        REG_UCP to make it available via the POSIX interface.
502    10. Added --line-buffered to pcregrep.
504    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
505        studied, and the match started with a letter with a code point greater than
506        127 whose first byte was different to the first byte of the other case of
507        the letter, the other case of this starting letter was not recognized
508        (#976).
510    12. If a pattern that was studied started with a repeated Unicode property
511        test, for example, \p{Nd}+, there was the theoretical possibility of
512        setting up an incorrect bitmap of starting bytes, but fortunately it could
513        not have actually happened in practice until change 8 above was made (it
514        added property types that matched character-matching opcodes).
516    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
517        possible starting bytes for non-anchored patterns.
519    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
520        \R, and also a number of cases that involve Unicode properties, both
521        explicit and implicit when PCRE_UCP is set.
523    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
524        input, it could crash or give wrong results if characters with values
525        greater than 0xc0 were present in the subject string. (Detail: it assumed
526        UTF-8 input when processing these items.)
528    16. Added a lot of (int) casts to avoid compiler warnings in systems where
529        size_t is 64-bit (#991).
531    17. Added a check for running out of memory when PCRE is compiled with
532        --disable-stack-for-recursion (#990).
534    18. If the last data line in a file for pcretest does not have a newline on
535        the end, a newline was missing in the output.
537    19. The default pcre_chartables.c file recognizes only ASCII characters (values
538        less than 128) in its various bitmaps. However, there is a facility for
539        generating tables according to the current locale when PCRE is compiled. It
540        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
541        characters, are recognized by isspace() and therefore were getting set in
542        these tables, and indeed these tables seem to approximate to ISO 8859. This
543        caused a problem in UTF-8 mode when pcre_study() was used to create a list
544        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
545        which of course cannot start UTF-8 characters. I have changed the code so
546        that only real ASCII characters (less than 128) and the correct starting
547        bytes for UTF-8 encodings are set for characters greater than 127 when in
548        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
549        altogether.)
551    20. Added the /T option to pcretest so as to be able to run tests with non-
552        standard character tables, thus making it possible to include the tests
553        used for 19 above in the standard set of tests.
555    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
556        reference to a subpattern the other side of a comment that contains an
557        opening parenthesis caused either an internal compiling error, or a
558        reference to the wrong subpattern.
561    Version 8.02 19-Mar-2010
562    ------------------------
564    1.  The Unicode data tables have been updated to Unicode 5.2.0.
566    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
567        configured.
569    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
570        original author of that file, following a query about its status.
572    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
573        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
575    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
576        quantifier applied to a forward-referencing subroutine call, could compile
577        incorrect code or give the error "internal error: previously-checked
578        referenced subpattern not found".
580    6.  Both MS Visual Studio and Symbian OS have problems with initializing
581        variables to point to external functions. For these systems, therefore,
582        pcre_malloc etc. are now initialized to local functions that call the
583        relevant global functions.
585    7.  There were two entries missing in the vectors called coptable and poptable
586        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
587        I've fixed the data, and added a kludgy way of testing at compile time that
588        the lengths are correct (equal to the number of opcodes).
590    8.  Following on from 7, I added a similar kludge to check the length of the
591        eint vector in pcreposix.c.
593    9.  Error texts for pcre_compile() are held as one long string to avoid too
594        much relocation at load time. To find a text, the string is searched,
595        counting zeros. There was no check for running off the end of the string,
596        which could happen if a new error number was added without updating the
597        string.
599    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
601    11. \K was not working if it appeared in an atomic group or in a group that
602        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
603        \K is "not well defined" if used in an assertion. PCRE now accepts it if
604        the assertion is positive, but not if it is negative.
606    12. Change 11 fortuitously reduced the size of the stack frame used in the
607        "match()" function of pcre_exec.c by one pointer. Forthcoming
608        implementation of support for (*MARK) will need an extra pointer on the
609        stack; I have reserved it now, so that the stack frame size does not
610        decrease.
612    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
613        item in branch that calls a recursion is a subroutine call - as in the
614        second branch in the above example - was incorrectly given the compile-
615        time error "recursive call could loop indefinitely" because pcre_compile()
616        was not correctly checking the subroutine for matching a non-empty string.
618    14. The checks for overrunning compiling workspace could trigger after an
619        overrun had occurred. This is a "should never occur" error, but it can be
620        triggered by pathological patterns such as hundreds of nested parentheses.
621        The checks now trigger 100 bytes before the end of the workspace.
623    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
626    Version 8.01 19-Jan-2010
627    ------------------------
629    1.  If a pattern contained a conditional subpattern with only one branch (in
630        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
631        computed the wrong minimum data length (which is of course zero for such
632        subpatterns). This could cause incorrect "no match" results.
634    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
635        the pattern is reset in the first branch, pcre_compile() failed with
636        "internal error: code overflow at offset...". This happened only when
637        the reset was to the original external option setting. (An optimization
638        abstracts leading options settings into an external setting, which was the
639        cause of this.)
641    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
642        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
643        assertion pattern did not match (meaning that the assertion was true), it
644        was incorrectly treated as false if the SKIP had been reached during the
645        matching. This also applied to assertions used as conditions.
647    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
648        assertion subpattern, including such a pattern used as a condition,
649        unpredictable results occurred, instead of the error return
652    5.  The C++ GlobalReplace function was not working like Perl for the special
653        situation when an empty string is matched. It now does the fancy magic
654        stuff that is necessary.
656    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
657        removed. (These were left over from very, very early versions of PCRE.)
659    7.  Some cosmetic changes to the code to make life easier when compiling it
660        as part of something else:
662        (a) Change DEBUG to PCRE_DEBUG.
664        (b) In pcre_compile(), rename the member of the "branch_chain" structure
665            called "current" as "current_branch", to prevent a collision with the
666            Linux macro when compiled as a kernel module.
668        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
669            prevent a collision with the Linux macro when compiled as a kernel
670            module.
672    8.  In pcre_compile() there are some checks for integer overflows that used to
673        cast potentially large values to (double). This has been changed to that
674        when building, a check for int64_t is made, and if it is found, it is used
675        instead, thus avoiding the use of floating point arithmetic. (There is no
676        other use of FP in PCRE.) If int64_t is not found, the fallback is to
677        double.
679    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
680        2005 (difference between two addresses compared to an unsigned value).
682    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
683        custom one, because of the following reported problem in Windows:
685          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
686              under Win32.
687          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
688              therefore missing the function definition.
689          - The compiler thus generates a "C" signature for the test function.
690          - The linker fails to find the "C" function.
691          - PCRE fails to configure if asked to do so against libbz2.
693    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
694        messages were output:
696          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
697          rerunning libtoolize, to keep the correct libtool macros in-tree.
698          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
700        I have done both of these things.
702    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
703        most of the time, it *can* run out if it is given a pattern that contains a
704        runaway infinite recursion. I updated the discussion in the pcrestack man
705        page.
707    13. Now that we have gone to the x.xx style of version numbers, the minor
708        version may start with zero. Using 08 or 09 is a bad idea because users
709        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
710        interpreted as invalid octal numbers. I've updated the previous comment in
711        configure.ac, and also added a check that gives an error if 08 or 09 are
712        used.
714    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
715        causing partial matching to fail when the end of the subject matched \W
716        in a UTF-8 pattern where \W was quantified with a minimum of 3.
718    15. There were some discrepancies between the declarations in pcre_internal.h
719        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
720        their definitions. The declarations used "const uschar *" and the
721        definitions used USPTR. Even though USPTR is normally defined as "const
722        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
723        reported that: "This difference in casting confuses some C++ compilers, for
724        example, SunCC recognizes above declarations as different functions and
725        generates broken code for hbpcre." I have changed the declarations to use
726        USPTR.
728    16. GNU libtool is named differently on some systems. The autogen.sh script now
729        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
730        (FreeBSD).
732    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
733        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
734        comment: "Figure out how to create a longlong from a string: strtoll and
735        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
736        instance, but it only takes 2 args instead of 3!"
738    18. A subtle bug concerned with back references has been fixed by a change of
739        specification, with a corresponding code fix. A pattern such as
740        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
741        refers, was giving matches when it shouldn't. For example, xa=xaaa would
742        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
743        same bug. Such groups have to be quantified to be useful, or contained
744        inside another quantified group. (If there's no repetition, the reference
745        can never match.) The problem arises because, having left the group and
746        moved on to the rest of the pattern, a later failure that backtracks into
747        the group uses the captured value from the final iteration of the group
748        rather than the correct earlier one. I have fixed this in PCRE by forcing
749        any group that contains a reference to itself to be an atomic group; that
750        is, there cannot be any backtracking into it once it has completed. This is
751        similar to recursive and subroutine calls.
754    Version 8.00 19-Oct-09
755    ----------------------
757    1.  The table for translating pcre_compile() error codes into POSIX error codes
758        was out-of-date, and there was no check on the pcre_compile() error code
759        being within the table. This could lead to an OK return being given in
760        error.
762    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
763        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
764        in a Windows environment.
766    3.  The pcregrep --count option prints the count for each file even when it is
767        zero, as does GNU grep. However, pcregrep was also printing all files when
768        --files-with-matches was added. Now, when both options are given, it prints
769        counts only for those files that have at least one match. (GNU grep just
770        prints the file name in this circumstance, but including the count seems
771        more useful - otherwise, why use --count?) Also ensured that the
772        combination -clh just lists non-zero counts, with no names.
774    4.  The long form of the pcregrep -F option was incorrectly implemented as
775        --fixed_strings instead of --fixed-strings. This is an incompatible change,
776        but it seems right to fix it, and I didn't think it was worth preserving
777        the old behaviour.
779    5.  The command line items --regex=pattern and --regexp=pattern were not
780        recognized by pcregrep, which required --regex pattern or --regexp pattern
781        (with a space rather than an '='). The man page documented the '=' forms,
782        which are compatible with GNU grep; these now work.
784    6.  No libpcreposix.pc file was created for pkg-config; there was just
785        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
787    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
788        when UCP support is not needed, by modifying the Python script that
789        generates it from Unicode data files. This should not matter if the module
790        is correctly used as a library, but I received one complaint about 50K of
791        unwanted data. My guess is that the person linked everything into his
792        program rather than using a library. Anyway, it does no harm.
794    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
795        was a minimum greater than 1 for a wide character in a possessive
796        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
797        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
798        character. Chaos in the form of incorrect output or a compiling loop could
799        result.
801    9.  The restrictions on what a pattern can contain when partial matching is
802        requested for pcre_exec() have been removed. All patterns can now be
803        partially matched by this function. In addition, if there are at least two
804        slots in the offset vector, the offset of the earliest inspected character
805        for the match and the offset of the end of the subject are set in them when
806        PCRE_ERROR_PARTIAL is returned.
808    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
809        synonymous with PCRE_PARTIAL, for backwards compatibility, and
810        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
811        and may be more useful for multi-segment matching.
813    11. Partial matching with pcre_exec() is now more intuitive. A partial match
814        used to be given if ever the end of the subject was reached; now it is
815        given only if matching could not proceed because another character was
816        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
817        string "Z", which now yields "no match" instead of "partial match". In the
818        case of pcre_dfa_exec(), "no match" is given if every matching path for the
819        final character ended with (*FAIL).
821    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
822        if the pattern had a "must contain" character that was already found in the
823        earlier partial match, unless partial matching was again requested. For
824        example, with the pattern /dog.(body)?/, the "must contain" character is
825        "g". If the first part-match was for the string "dog", restarting with
826        "sbody" failed. This bug has been fixed.
828    13. The string returned by pcre_dfa_exec() after a partial match has been
829        changed so that it starts at the first inspected character rather than the
830        first character of the match. This makes a difference only if the pattern
831        starts with a lookbehind assertion or \b or \B (\K is not supported by
832        pcre_dfa_exec()). It's an incompatible change, but it makes the two
833        matching functions compatible, and I think it's the right thing to do.
835    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
836        so that the demonstration program is easily available in environments where
837        PCRE has not been installed from source.
839    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
840        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
841        library.
843    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
844        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
845        is not the first non-POSIX option to be added. Clearly some people find
846        these options useful.
848    17. If a caller to the POSIX matching function regexec() passes a non-zero
849        value for nmatch with a NULL value for pmatch, the value of
850        nmatch is forced to zero.
852    18. RunGrepTest did not have a test for the availability of the -u option of
853        the diff command, as RunTest does. It now checks in the same way as
854        RunTest, and also checks for the -b option.
856    19. If an odd number of negated classes containing just a single character
857        interposed, within parentheses, between a forward reference to a named
858        subpattern and the definition of the subpattern, compilation crashed with
859        an internal error, complaining that it could not find the referenced
860        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
861        [The bug was that it was starting one character too far in when skipping
862        over the character class, thus treating the ] as data rather than
863        terminating the class. This meant it could skip too much.]
865    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
866        /g option in pcretest when the pattern contains \K, which makes it possible
867        to have an empty string match not at the start, even when the pattern is
868        anchored. Updated pcretest and pcredemo to use this option.
870    21. If the maximum number of capturing subpatterns in a recursion was greater
871        than the maximum at the outer level, the higher number was returned, but
872        with unset values at the outer level. The correct (outer level) value is
873        now given.
875    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
876        PCRE did not set those parentheses (unlike Perl). I have now found a way to
877        make it do so. The string so far is captured, making this feature
878        compatible with Perl.
880    23. The tests have been re-organized, adding tests 11 and 12, to make it
881        possible to check the Perl 5.10 features against Perl 5.10.
883    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
884        pattern matches a fixed length string. PCRE did not allow this; now it
885        does. Neither allows recursion.
887    25. I finally figured out how to implement a request to provide the minimum
888        length of subject string that was needed in order to match a given pattern.
889        (It was back references and recursion that I had previously got hung up
890        on.) This code has now been added to pcre_study(); it finds a lower bound
891        to the length of subject needed. It is not necessarily the greatest lower
892        bound, but using it to avoid searching strings that are too short does give
893        some useful speed-ups. The value is available to calling programs via
894        pcre_fullinfo().
896    26. While implementing 25, I discovered to my embarrassment that pcretest had
897        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
898        study optimizations had never been tested with that matching function.
899        Oops. What is worse, even when it was passed study data, there was a bug in
900        pcre_dfa_exec() that meant it never actually used it. Double oops. There
901        were also very few tests of studied patterns with pcre_dfa_exec().
903    27. If (?| is used to create subpatterns with duplicate numbers, they are now
904        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
905        on the other side of the coin, they are no longer allowed to have different
906        names, because these cannot be distinguished in PCRE, and this has caused
907        confusion. (This is a difference from Perl.)
909    28. When duplicate subpattern names are present (necessarily with different
910        numbers, as required by 27 above), and a test is made by name in a
911        conditional pattern, either for a subpattern having been matched, or for
912        recursion in such a pattern, all the associated numbered subpatterns are
913        tested, and the overall condition is true if the condition is true for any
914        one of them. This is the way Perl works, and is also more like the way
915        testing by number works.
918    Version 7.9 11-Apr-09
919  ---------------------  ---------------------
921  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 931  Version 7.9 xx-xxx-09
931      but BOOL is not.      but BOOL is not.
933  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
934      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
936  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
937      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 94  Version 7.9 xx-xxx-09 Line 1008  Version 7.9 xx-xxx-09
1008  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name  23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1009      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is      CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1010      included within another project.      included within another project.
1012  24. Steven Van Ingelgem's patches to add more options to the CMake support,  24. Steven Van Ingelgem's patches to add more options to the CMake support,
1013      slightly modified by me:      slightly modified by me:
1015        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including        (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1016            not building pcregrep.            not building pcregrep.
1018        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only        (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1019            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.            if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1021  25. Forward references, both numeric and by name, in patterns that made use of  25. Forward references, both numeric and by name, in patterns that made use of
1022      duplicate group numbers, could behave incorrectly or give incorrect errors,      duplicate group numbers, could behave incorrectly or give incorrect errors,
1023      because when scanning forward to find the reference group, PCRE was not      because when scanning forward to find the reference group, PCRE was not
1024      taking into account the duplicate group numbers. A pattern such as      taking into account the duplicate group numbers. A pattern such as
1025      ^X(?3)(a)(?|(b)|(q))(Y) is an example.      ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1027    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1028        the feature of a custom pointer more persuasive (as requested by a user).
1030    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1031        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1032        pre-defined.
1034    28. Added support for (*UTF8) at the start of a pattern.
1036    29. Arrange for flags added by the "release type" setting in CMake to be shown
1037        in the configuration summary.
1040  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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