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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  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.
30    Version 8.13 16-Aug-2011
31    ------------------------
33    1.  The Unicode data tables have been updated to Unicode 6.0.0.
35    2.  Two minor typos in pcre_internal.h have been fixed.
37    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
38        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
39        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
41    4.  There were a number of related bugs in the code for matching backrefences
42        caselessly in UTF-8 mode when codes for the characters concerned were
43        different numbers of bytes. For example, U+023A and U+2C65 are an upper
44        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
45        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
46        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
47        2-byte code at the end of the subject (it thought there wasn't enough data
48        left).
50    5.  Comprehensive information about what went wrong is now returned by
51        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
52        as the output vector has at least 2 elements. The offset of the start of
53        the failing character and a reason code are placed in the vector.
55    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
56        now returned is for the first byte of the failing character, instead of the
57        last byte inspected. This is an incompatible change, but I hope it is small
58        enough not to be a problem. It makes the returned offset consistent with
59        pcre_exec() and pcre_dfa_exec().
61    7.  pcretest now gives a text phrase as well as the error number when
62        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
63        failure, the offset and reason code are output.
65    8.  When \R was used with a maximizing quantifier it failed to skip backwards
66        over a \r\n pair if the subsequent match failed. Instead, it just skipped
67        back over a single character (\n). This seems wrong (because it treated the
68        two characters as a single entity when going forwards), conflicts with the
69        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
70        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
71        has been changed.
73    9.  Some internal refactoring has changed the processing so that the handling
74        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
75        time (the PCRE_DOTALL option was changed this way some time ago: version
76        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
77        which was always a bit of a fudge. It also means that there is one less
78        argument for the match() function, which reduces its stack requirements
79        slightly. This change also fixes an incompatibility with Perl: the pattern
80        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
82    10. More internal refactoring has drastically reduced the number of recursive
83        calls to match() for possessively repeated groups such as (abc)++ when
84        using pcre_exec().
86    11. While implementing 10, a number of bugs in the handling of groups were
87        discovered and fixed:
89        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
90        (a|)*(?1) gave a compile-time internal error.
91        ((a|)+)+  did not notice that the outer group could match an empty string.
92        (^a|^)+   was not marked as anchored.
93        (.*a|.*)+ was not marked as matching at start or after a newline.
95    12. Yet more internal refactoring has removed another argument from the match()
96        function. Special calls to this function are now indicated by setting a
97        value in a variable in the "match data" data block.
99    13. Be more explicit in pcre_study() instead of relying on "default" for
100        opcodes that mean there is no starting character; this means that when new
101        ones are added and accidentally left out of pcre_study(), testing should
102        pick them up.
104    14. The -s option of pcretest has been documented for ages as being an old
105        synonym of -m (show memory usage). I have changed it to mean "force study
106        for every regex", that is, assume /S for every regex. This is similar to -i
107        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
108        using it. It makes it easier to run collections of tests with and without
109        study enabled, and thereby test pcre_study() more easily. All the standard
110        tests are now run with and without -s (but some patterns can be marked as
111        "never study" - see 20 below).
113    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
114        restoration of the capturing data to the outer values was not happening
115        correctly.
117    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
118        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
119        pattern had matched an empty string, and so incorrectly returned a no
120        match.
122    17. There was optimizing code for the last branch of non-capturing parentheses,
123        and also for the obeyed branch of a conditional subexpression, which used
124        tail recursion to cut down on stack usage. Unfortunately, now that there is
125        the possibility of (*THEN) occurring in these branches, tail recursion is
126        no longer possible because the return has to be checked for (*THEN). These
127        two optimizations have therefore been removed.
129    18. If a pattern containing \R was studied, it was assumed that \R always
130        matched two bytes, thus causing the minimum subject length to be
131        incorrectly computed because \R can also match just one byte.
133    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
134        was incorrectly computed.
136    20. If /S is present twice on a test pattern in pcretest input, it now
137        *disables* studying, thereby overriding the use of -s on the command line
138        (see 14 above). This is necessary for one or two tests to keep the output
139        identical in both cases.
141    21. When (*ACCEPT) was used in an assertion that matched an empty string and
142        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
144    22. When an atomic group that contained a capturing parenthesis was
145        successfully matched, but the branch in which it appeared failed, the
146        capturing was not being forgotten if a higher numbered group was later
147        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
148        group 1 to "a", when in fact it should be unset. This applied to multi-
149        branched capturing and non-capturing groups, repeated or not, and also to
150        positive assertions (capturing in negative assertions does not happen
151        in PCRE) and also to nested atomic groups.
153    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
154        subject after a captured substring, to make it easier to tell which of a
155        number of identical substrings has been captured.
157    24. The way atomic groups are processed by pcre_exec() has been changed so that
158        if they are repeated, backtracking one repetition now resets captured
159        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
160        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
161        "aaa". Previously, it would have been "a". As part of this code
162        refactoring, the way recursive calls are handled has also been changed.
164    25. If an assertion condition captured any substrings, they were not passed
165        back unless some other capturing happened later. For example, if
166        (?(?=(a))a) was matched against "a", no capturing was returned.
168    26. When studying a pattern that contained subroutine calls or assertions,
169        the code for finding the minimum length of a possible match was handling
170        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
171        group 1 called group 2 while simultaneously a separate group 2 called group
172        1). A stack overflow occurred in this case. I have fixed this by limiting
173        the recursion depth to 10.
175    27. Updated RunTest.bat in the distribution to the version supplied by Tom
176        Fortmann. This supports explicit test numbers on the command line, and has
177        argument validation and error reporting.
179    28. An instance of \X with an unlimited repeat could fail if at any point the
180        first character it looked at was a mark character.
182    29. Some minor code refactoring concerning Unicode properties and scripts
183        should reduce the stack requirement of match() slightly.
185    30. Added the '=' option to pcretest to check the setting of unused capturing
186        slots at the end of the pattern, which are documented as being -1, but are
187        not included in the return count.
189    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
190        compiled something random. Now it gives a compile-time error (as does
191        Perl).
193    32. A *MARK encountered during the processing of a positive assertion is now
194        recorded and passed back (compatible with Perl).
196    33. If --only-matching or --colour was set on a pcregrep call whose pattern
197        had alternative anchored branches, the search for a second match in a line
198        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
199        matched the line "0102" twice. The same bug affected patterns that started
200        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
201        twice.
203    34. Previously, PCRE did not allow quantification of assertions. However, Perl
204        does, and because of capturing effects, quantifying parenthesized
205        assertions may at times be useful. Quantifiers are now allowed for
206        parenthesized assertions.
208    35. A minor code tidy in pcre_compile() when checking options for \R usage.
210    36. \g was being checked for fancy things in a character class, when it should
211        just be a literal "g".
213    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
214        appearance of a nested POSIX class supersedes an apparent external class.
215        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
216        unescaped square brackets may also appear as part of class names. For
217        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
218        more like Perl. (But see 8.20/1 above.)
220    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
221        was because it thought it was \N{name}, which is not supported).
223    39. Add minix to OS list not supporting the -S option in pcretest.
225    40. PCRE tries to detect cases of infinite recursion at compile time, but it
226        cannot analyze patterns in sufficient detail to catch mutual recursions
227        such as ((?1))((?2)). There is now a runtime test that gives an error if a
228        subgroup is called recursively as a subpattern for a second time at the
229        same position in the subject string. In previous releases this might have
230        been caught by the recursion limit, or it might have run out of stack.
232    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
233        happen only once. PCRE was, however incorrectly giving a compile time error
234        "recursive call could loop indefinitely" because it cannot analyze the
235        pattern in sufficient detail. The compile time test no longer happens when
236        PCRE is compiling a conditional subpattern, but actual runaway loops are
237        now caught at runtime (see 40 above).
239    42. It seems that Perl allows any characters other than a closing parenthesis
240        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
241        has been changed to be the same.
243    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
244        as not to get warnings when autogen.sh is called. Also changed
245        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
247    44. To help people who use pcregrep to scan files containing exceedingly long
248        lines, the following changes have been made:
250        (a) The default value of the buffer size parameter has been increased from
251            8K to 20K. (The actual buffer used is three times this size.)
253        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
254            PCRE is built.
256        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
257            to be set at run time.
259        (d) Numerical values in pcregrep options can be followed by K or M, for
260            example --buffer-size=50K.
262        (e) If a line being scanned overflows pcregrep's buffer, an error is now
263            given and the return code is set to 2.
265    45. Add a pointer to the latest mark to the callout data block.
267    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
268        partial match of an empty string instead of no match. This was specific to
269        the use of ".".
271    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
272        complete match instead of a partial match. This bug was dependent on both
273        the PCRE_UTF8 and PCRE_DOTALL options being set.
275    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
276        starting byte set, because \b was not being ignored.
279    Version 8.12 15-Jan-2011
280    ------------------------
282    1.  Fixed some typos in the markup of the man pages, and wrote a script that
283        checks for such things as part of the documentation building process.
285    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
286        --match-limit and --recursion-limit options (added for 8.11). In
287        particular, this made one of the standard tests fail. (The integer value
288        went into the wrong half of a long int.)
290    3.  If the --colour option was given to pcregrep with -v (invert match), it
291        did strange things, either producing crazy output, or crashing. It should,
292        of course, ignore a request for colour when reporting lines that do not
293        match.
295    4.  Another pcregrep bug caused similar problems if --colour was specified with
296        -M (multiline) and the pattern match finished with a line ending.
298    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
299        matched in multiline mode, the following line was shown as part of the
300        match. This seems wrong, so I have changed it.
302    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
303        the check for further matches in the same line (so they could be coloured)
304        to overrun the end of the current line. If another match was found, it was
305        incorrectly shown (and then shown again when found in the next line).
307    7.  If pcregrep was compiled under Windows, there was a reference to the
308        function pcregrep_exit() before it was defined. I am assuming this was
309        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
310        reported by a user. I've moved the definition above the reference.
313    Version 8.11 10-Dec-2010
314    ------------------------
316    1.  (*THEN) was not working properly if there were untried alternatives prior
317        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
318        backtracked to try for "b" instead of moving to the next alternative branch
319        at the same level (in this case, to look for "c"). The Perl documentation
320        is clear that when (*THEN) is backtracked onto, it goes to the "next
321        alternative in the innermost enclosing group".
323    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
324        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
325        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
326        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
327        (*THEN).
329    3.  If \s appeared in a character class, it removed the VT character from
330        the class, even if it had been included by some previous item, for example
331        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
332        of \s, but is part of the POSIX "space" class.)
334    4.  A partial match never returns an empty string (because you can always
335        match an empty string at the end of the subject); however the checking for
336        an empty string was starting at the "start of match" point. This has been
337        changed to the "earliest inspected character" point, because the returned
338        data for a partial match starts at this character. This means that, for
339        example, /(?<=abc)def/ gives a partial match for the subject "abc"
340        (previously it gave "no match").
342    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
343        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
344        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
345        has an implication that the given string is incomplete (because a partial
346        match is preferred over a full match). For this reason, these items now
347        give a partial match in this situation. [Aside: previously, the one case
348        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
349        match rather than a full match, which was wrong by the old rules, but is
350        now correct.]
352    6.  There was a bug in the handling of #-introduced comments, recognized when
353        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
354        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
355        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
356        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
357        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
358        places in pcre_compile().
360    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
361        comments when looking ahead for named forward references to subpatterns,
362        the only newline sequence it recognized was NL. It now handles newlines
363        according to the set newline convention.
365    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
366        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
367        cater for a lack of strerror(). These oversights have been fixed.
369    9.  Added --match-limit and --recursion-limit to pcregrep.
371    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
373    11. When the -o option was used, pcregrep was setting a return code of 1, even
374        when matches were found, and --line-buffered was not being honoured.
376    12. Added an optional parentheses number to the -o and --only-matching options
377        of pcregrep.
379    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
380        can match an empty string. The code to do it in pcretest and pcredemo
381        needed fixing:
383        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
384            only one byte after an empty string match just before CRLF (this case
385            just got forgotten; "any" and "anycrlf" were OK).
387        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
388            mode when an empty string match preceded an ASCII character followed by
389            a non-ASCII character. (The code for advancing by one character rather
390            than one byte was nonsense.)
392        (c) The pcredemo.c sample program did not have any code at all to handle
393            the cases when CRLF is a valid newline sequence.
395    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
396        as a starting offset was within the subject string. There is now a new
397        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
398        negative or greater than the length of the string. In order to test this,
399        pcretest is extended to allow the setting of negative starting offsets.
401    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
402        starting offset points to the beginning of a UTF-8 character was
403        unnecessarily clumsy. I tidied it up.
405    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
406        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
408    17. Nobody had reported that the --include_dir option, which was added in
409        release 7.7 should have been called --include-dir (hyphen, not underscore)
410        for compatibility with GNU grep. I have changed it to --include-dir, but
411        left --include_dir as an undocumented synonym, and the same for
412        --exclude-dir, though that is not available in GNU grep, at least as of
413        release 2.5.4.
415    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
416        characters from a string of bytes) have been redefined so as not to use
417        loops, in order to improve performance in some environments. At the same
418        time, I abstracted some of the common code into auxiliary macros to save
419        repetition (this should not affect the compiled code).
421    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
422        compile-time error is now given if \c is not followed by an ASCII
423        character, that is, a byte less than 128. (In EBCDIC mode, the code is
424        different, and any byte value is allowed.)
426    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
427        START_OPTIMIZE option, which is now allowed at compile time - but just
428        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
429        to pcregrep and other applications that have no direct access to PCRE
430        options. The new /Y option in pcretest sets this option when calling
431        pcre_compile().
433    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
434        back references. Groups containing recursive back references were forced to
435        be atomic by that change, but in the case of named groups, the amount of
436        memory required was incorrectly computed, leading to "Failed: internal
437        error: code overflow". This has been fixed.
439    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
440        pcretest.c, to avoid build problems in some Borland environments.
443    Version 8.10 25-Jun-2010
444    ------------------------
446    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
447        THEN.
449    2.  (*ACCEPT) was not working when inside an atomic group.
451    3.  Inside a character class, \B is treated as a literal by default, but
452        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
453        causes the error). The code is unchanged, but I tidied the documentation.
455    4.  Inside a character class, PCRE always treated \R and \X as literals,
456        whereas Perl faults them if its -w option is set. I have changed PCRE so
457        that it faults them when PCRE_EXTRA is set.
459    5.  Added support for \N, which always matches any character other than
460        newline. (It is the same as "." when PCRE_DOTALL is not set.)
462    6.  When compiling pcregrep with newer versions of gcc which may have
463        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
464        declared with attribute warn_unused_result" were given. Just casting the
465        result to (void) does not stop the warnings; a more elaborate fudge is
466        needed. I've used a macro to implement this.
468    7.  Minor change to pcretest.c to avoid a compiler warning.
470    8.  Added four artifical Unicode properties to help with an option to make
471        \s etc use properties (see next item). The new properties are: Xan
472        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
474    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
475        use Unicode properties. (*UCP) at the start of a pattern can be used to set
476        this option. Modified pcretest to add /W to test this facility. Added
477        REG_UCP to make it available via the POSIX interface.
479    10. Added --line-buffered to pcregrep.
481    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
482        studied, and the match started with a letter with a code point greater than
483        127 whose first byte was different to the first byte of the other case of
484        the letter, the other case of this starting letter was not recognized
485        (#976).
487    12. If a pattern that was studied started with a repeated Unicode property
488        test, for example, \p{Nd}+, there was the theoretical possibility of
489        setting up an incorrect bitmap of starting bytes, but fortunately it could
490        not have actually happened in practice until change 8 above was made (it
491        added property types that matched character-matching opcodes).
493    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
494        possible starting bytes for non-anchored patterns.
496    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
497        \R, and also a number of cases that involve Unicode properties, both
498        explicit and implicit when PCRE_UCP is set.
500    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
501        input, it could crash or give wrong results if characters with values
502        greater than 0xc0 were present in the subject string. (Detail: it assumed
503        UTF-8 input when processing these items.)
505    16. Added a lot of (int) casts to avoid compiler warnings in systems where
506        size_t is 64-bit (#991).
508    17. Added a check for running out of memory when PCRE is compiled with
509        --disable-stack-for-recursion (#990).
511    18. If the last data line in a file for pcretest does not have a newline on
512        the end, a newline was missing in the output.
514    19. The default pcre_chartables.c file recognizes only ASCII characters (values
515        less than 128) in its various bitmaps. However, there is a facility for
516        generating tables according to the current locale when PCRE is compiled. It
517        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
518        characters, are recognized by isspace() and therefore were getting set in
519        these tables, and indeed these tables seem to approximate to ISO 8859. This
520        caused a problem in UTF-8 mode when pcre_study() was used to create a list
521        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
522        which of course cannot start UTF-8 characters. I have changed the code so
523        that only real ASCII characters (less than 128) and the correct starting
524        bytes for UTF-8 encodings are set for characters greater than 127 when in
525        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
526        altogether.)
528    20. Added the /T option to pcretest so as to be able to run tests with non-
529        standard character tables, thus making it possible to include the tests
530        used for 19 above in the standard set of tests.
532    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
533        reference to a subpattern the other side of a comment that contains an
534        opening parenthesis caused either an internal compiling error, or a
535        reference to the wrong subpattern.
538    Version 8.02 19-Mar-2010
539    ------------------------
541    1.  The Unicode data tables have been updated to Unicode 5.2.0.
543    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
544        configured.
546    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
547        original author of that file, following a query about its status.
549    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
550        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
552    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
553        quantifier applied to a forward-referencing subroutine call, could compile
554        incorrect code or give the error "internal error: previously-checked
555        referenced subpattern not found".
557    6.  Both MS Visual Studio and Symbian OS have problems with initializing
558        variables to point to external functions. For these systems, therefore,
559        pcre_malloc etc. are now initialized to local functions that call the
560        relevant global functions.
562    7.  There were two entries missing in the vectors called coptable and poptable
563        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
564        I've fixed the data, and added a kludgy way of testing at compile time that
565        the lengths are correct (equal to the number of opcodes).
567    8.  Following on from 7, I added a similar kludge to check the length of the
568        eint vector in pcreposix.c.
570    9.  Error texts for pcre_compile() are held as one long string to avoid too
571        much relocation at load time. To find a text, the string is searched,
572        counting zeros. There was no check for running off the end of the string,
573        which could happen if a new error number was added without updating the
574        string.
576    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
578    11. \K was not working if it appeared in an atomic group or in a group that
579        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
580        \K is "not well defined" if used in an assertion. PCRE now accepts it if
581        the assertion is positive, but not if it is negative.
583    12. Change 11 fortuitously reduced the size of the stack frame used in the
584        "match()" function of pcre_exec.c by one pointer. Forthcoming
585        implementation of support for (*MARK) will need an extra pointer on the
586        stack; I have reserved it now, so that the stack frame size does not
587        decrease.
589    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
590        item in branch that calls a recursion is a subroutine call - as in the
591        second branch in the above example - was incorrectly given the compile-
592        time error "recursive call could loop indefinitely" because pcre_compile()
593        was not correctly checking the subroutine for matching a non-empty string.
595    14. The checks for overrunning compiling workspace could trigger after an
596        overrun had occurred. This is a "should never occur" error, but it can be
597        triggered by pathological patterns such as hundreds of nested parentheses.
598        The checks now trigger 100 bytes before the end of the workspace.
600    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
603    Version 8.01 19-Jan-2010
604    ------------------------
606    1.  If a pattern contained a conditional subpattern with only one branch (in
607        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
608        computed the wrong minimum data length (which is of course zero for such
609        subpatterns). This could cause incorrect "no match" results.
611    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
612        the pattern is reset in the first branch, pcre_compile() failed with
613        "internal error: code overflow at offset...". This happened only when
614        the reset was to the original external option setting. (An optimization
615        abstracts leading options settings into an external setting, which was the
616        cause of this.)
618    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
619        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
620        assertion pattern did not match (meaning that the assertion was true), it
621        was incorrectly treated as false if the SKIP had been reached during the
622        matching. This also applied to assertions used as conditions.
624    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
625        assertion subpattern, including such a pattern used as a condition,
626        unpredictable results occurred, instead of the error return
629    5.  The C++ GlobalReplace function was not working like Perl for the special
630        situation when an empty string is matched. It now does the fancy magic
631        stuff that is necessary.
633    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
634        removed. (These were left over from very, very early versions of PCRE.)
636    7.  Some cosmetic changes to the code to make life easier when compiling it
637        as part of something else:
639        (a) Change DEBUG to PCRE_DEBUG.
641        (b) In pcre_compile(), rename the member of the "branch_chain" structure
642            called "current" as "current_branch", to prevent a collision with the
643            Linux macro when compiled as a kernel module.
645        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
646            prevent a collision with the Linux macro when compiled as a kernel
647            module.
649    8.  In pcre_compile() there are some checks for integer overflows that used to
650        cast potentially large values to (double). This has been changed to that
651        when building, a check for int64_t is made, and if it is found, it is used
652        instead, thus avoiding the use of floating point arithmetic. (There is no
653        other use of FP in PCRE.) If int64_t is not found, the fallback is to
654        double.
656    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
657        2005 (difference between two addresses compared to an unsigned value).
659    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
660        custom one, because of the following reported problem in Windows:
662          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
663              under Win32.
664          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
665              therefore missing the function definition.
666          - The compiler thus generates a "C" signature for the test function.
667          - The linker fails to find the "C" function.
668          - PCRE fails to configure if asked to do so against libbz2.
670    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
671        messages were output:
673          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
674          rerunning libtoolize, to keep the correct libtool macros in-tree.
675          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
677        I have done both of these things.
679    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
680        most of the time, it *can* run out if it is given a pattern that contains a
681        runaway infinite recursion. I updated the discussion in the pcrestack man
682        page.
684    13. Now that we have gone to the x.xx style of version numbers, the minor
685        version may start with zero. Using 08 or 09 is a bad idea because users
686        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
687        interpreted as invalid octal numbers. I've updated the previous comment in
688        configure.ac, and also added a check that gives an error if 08 or 09 are
689        used.
691    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
692        causing partial matching to fail when the end of the subject matched \W
693        in a UTF-8 pattern where \W was quantified with a minimum of 3.
695    15. There were some discrepancies between the declarations in pcre_internal.h
696        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
697        their definitions. The declarations used "const uschar *" and the
698        definitions used USPTR. Even though USPTR is normally defined as "const
699        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
700        reported that: "This difference in casting confuses some C++ compilers, for
701        example, SunCC recognizes above declarations as different functions and
702        generates broken code for hbpcre." I have changed the declarations to use
703        USPTR.
705    16. GNU libtool is named differently on some systems. The autogen.sh script now
706        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
707        (FreeBSD).
709    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
710        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
711        comment: "Figure out how to create a longlong from a string: strtoll and
712        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
713        instance, but it only takes 2 args instead of 3!"
715    18. A subtle bug concerned with back references has been fixed by a change of
716        specification, with a corresponding code fix. A pattern such as
717        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
718        refers, was giving matches when it shouldn't. For example, xa=xaaa would
719        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
720        same bug. Such groups have to be quantified to be useful, or contained
721        inside another quantified group. (If there's no repetition, the reference
722        can never match.) The problem arises because, having left the group and
723        moved on to the rest of the pattern, a later failure that backtracks into
724        the group uses the captured value from the final iteration of the group
725        rather than the correct earlier one. I have fixed this in PCRE by forcing
726        any group that contains a reference to itself to be an atomic group; that
727        is, there cannot be any backtracking into it once it has completed. This is
728        similar to recursive and subroutine calls.
731    Version 8.00 19-Oct-09
732    ----------------------
734    1.  The table for translating pcre_compile() error codes into POSIX error codes
735        was out-of-date, and there was no check on the pcre_compile() error code
736        being within the table. This could lead to an OK return being given in
737        error.
739    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
740        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
741        in a Windows environment.
743    3.  The pcregrep --count option prints the count for each file even when it is
744        zero, as does GNU grep. However, pcregrep was also printing all files when
745        --files-with-matches was added. Now, when both options are given, it prints
746        counts only for those files that have at least one match. (GNU grep just
747        prints the file name in this circumstance, but including the count seems
748        more useful - otherwise, why use --count?) Also ensured that the
749        combination -clh just lists non-zero counts, with no names.
751    4.  The long form of the pcregrep -F option was incorrectly implemented as
752        --fixed_strings instead of --fixed-strings. This is an incompatible change,
753        but it seems right to fix it, and I didn't think it was worth preserving
754        the old behaviour.
756    5.  The command line items --regex=pattern and --regexp=pattern were not
757        recognized by pcregrep, which required --regex pattern or --regexp pattern
758        (with a space rather than an '='). The man page documented the '=' forms,
759        which are compatible with GNU grep; these now work.
761    6.  No libpcreposix.pc file was created for pkg-config; there was just
762        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
764    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
765        when UCP support is not needed, by modifying the Python script that
766        generates it from Unicode data files. This should not matter if the module
767        is correctly used as a library, but I received one complaint about 50K of
768        unwanted data. My guess is that the person linked everything into his
769        program rather than using a library. Anyway, it does no harm.
771    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
772        was a minimum greater than 1 for a wide character in a possessive
773        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
774        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
775        character. Chaos in the form of incorrect output or a compiling loop could
776        result.
778    9.  The restrictions on what a pattern can contain when partial matching is
779        requested for pcre_exec() have been removed. All patterns can now be
780        partially matched by this function. In addition, if there are at least two
781        slots in the offset vector, the offset of the earliest inspected character
782        for the match and the offset of the end of the subject are set in them when
783        PCRE_ERROR_PARTIAL is returned.
785    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
786        synonymous with PCRE_PARTIAL, for backwards compatibility, and
787        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
788        and may be more useful for multi-segment matching.
790    11. Partial matching with pcre_exec() is now more intuitive. A partial match
791        used to be given if ever the end of the subject was reached; now it is
792        given only if matching could not proceed because another character was
793        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
794        string "Z", which now yields "no match" instead of "partial match". In the
795        case of pcre_dfa_exec(), "no match" is given if every matching path for the
796        final character ended with (*FAIL).
798    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
799        if the pattern had a "must contain" character that was already found in the
800        earlier partial match, unless partial matching was again requested. For
801        example, with the pattern /dog.(body)?/, the "must contain" character is
802        "g". If the first part-match was for the string "dog", restarting with
803        "sbody" failed. This bug has been fixed.
805    13. The string returned by pcre_dfa_exec() after a partial match has been
806        changed so that it starts at the first inspected character rather than the
807        first character of the match. This makes a difference only if the pattern
808        starts with a lookbehind assertion or \b or \B (\K is not supported by
809        pcre_dfa_exec()). It's an incompatible change, but it makes the two
810        matching functions compatible, and I think it's the right thing to do.
812    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
813        so that the demonstration program is easily available in environments where
814        PCRE has not been installed from source.
816    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
817        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
818        library.
820    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
821        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
822        is not the first non-POSIX option to be added. Clearly some people find
823        these options useful.
825    17. If a caller to the POSIX matching function regexec() passes a non-zero
826        value for nmatch with a NULL value for pmatch, the value of
827        nmatch is forced to zero.
829    18. RunGrepTest did not have a test for the availability of the -u option of
830        the diff command, as RunTest does. It now checks in the same way as
831        RunTest, and also checks for the -b option.
833    19. If an odd number of negated classes containing just a single character
834        interposed, within parentheses, between a forward reference to a named
835        subpattern and the definition of the subpattern, compilation crashed with
836        an internal error, complaining that it could not find the referenced
837        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
838        [The bug was that it was starting one character too far in when skipping
839        over the character class, thus treating the ] as data rather than
840        terminating the class. This meant it could skip too much.]
842    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
843        /g option in pcretest when the pattern contains \K, which makes it possible
844        to have an empty string match not at the start, even when the pattern is
845        anchored. Updated pcretest and pcredemo to use this option.
847    21. If the maximum number of capturing subpatterns in a recursion was greater
848        than the maximum at the outer level, the higher number was returned, but
849        with unset values at the outer level. The correct (outer level) value is
850        now given.
852    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
853        PCRE did not set those parentheses (unlike Perl). I have now found a way to
854        make it do so. The string so far is captured, making this feature
855        compatible with Perl.
857    23. The tests have been re-organized, adding tests 11 and 12, to make it
858        possible to check the Perl 5.10 features against Perl 5.10.
860    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
861        pattern matches a fixed length string. PCRE did not allow this; now it
862        does. Neither allows recursion.
864    25. I finally figured out how to implement a request to provide the minimum
865        length of subject string that was needed in order to match a given pattern.
866        (It was back references and recursion that I had previously got hung up
867        on.) This code has now been added to pcre_study(); it finds a lower bound
868        to the length of subject needed. It is not necessarily the greatest lower
869        bound, but using it to avoid searching strings that are too short does give
870        some useful speed-ups. The value is available to calling programs via
871        pcre_fullinfo().
873    26. While implementing 25, I discovered to my embarrassment that pcretest had
874        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
875        study optimizations had never been tested with that matching function.
876        Oops. What is worse, even when it was passed study data, there was a bug in
877        pcre_dfa_exec() that meant it never actually used it. Double oops. There
878        were also very few tests of studied patterns with pcre_dfa_exec().
880    27. If (?| is used to create subpatterns with duplicate numbers, they are now
881        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
882        on the other side of the coin, they are no longer allowed to have different
883        names, because these cannot be distinguished in PCRE, and this has caused
884        confusion. (This is a difference from Perl.)
886    28. When duplicate subpattern names are present (necessarily with different
887        numbers, as required by 27 above), and a test is made by name in a
888        conditional pattern, either for a subpattern having been matched, or for
889        recursion in such a pattern, all the associated numbered subpatterns are
890        tested, and the overall condition is true if the condition is true for any
891        one of them. This is the way Perl works, and is also more like the way
892        testing by number works.
895    Version 7.9 11-Apr-09
896  ---------------------  ---------------------
898  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 908  Version 7.9 xx-xxx-09
908      but BOOL is not.      but BOOL is not.
910  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
911      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.
913  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
914      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 95  Version 7.9 xx-xxx-09 Line 986  Version 7.9 xx-xxx-09
986      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
987      included within another project.      included within another project.
989    24. Steven Van Ingelgem's patches to add more options to the CMake support,
990        slightly modified by me:
992          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
993              not building pcregrep.
995          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
996              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
998    25. Forward references, both numeric and by name, in patterns that made use of
999        duplicate group numbers, could behave incorrectly or give incorrect errors,
1000        because when scanning forward to find the reference group, PCRE was not
1001        taking into account the duplicate group numbers. A pattern such as
1002        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1004    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1005        the feature of a custom pointer more persuasive (as requested by a user).
1007    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1008        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1009        pre-defined.
1011    28. Added support for (*UTF8) at the start of a pattern.
1013    29. Arrange for flags added by the "release type" setting in CMake to be shown
1014        in the configuration summary.
1017  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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