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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.20 23-Sep-2011
5    ------------------------
6    
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.
12    
13    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
14        captured substring, but while checking the failing first alternative,
15        substring 1 is temporarily captured. If the output vector supplied to
16        pcre_exec() was not big enough for this capture, the yield of the function
17        was still zero ("insufficient space for captured substrings"). This cannot
18        be totally fixed without adding another stack variable, which seems a lot
19        of expense for a edge case. However, I have improved the situation in cases
20        such as /(a)(b)x|abc/ matched against "abc", where the return code
21        indicates that fewer than the maximum number of slots in the ovector have
22        been set.
23    
24    3.  Related to (2) above: when there are more back references in a pattern than
25        slots in the output vector, pcre_exec() uses temporary memory during
26        matching, and copies in the captures as far as possible afterwards. It was
27        using the entire output vector, but this conflicts with the specification
28        that only 2/3 is used for passing back captured substrings. Now it uses
29        only the first 2/3, for compatibility. This is, of course, another edge
30        case.
31    
32    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
33        main code base, and can be used by building with --enable-jit. When this is
34        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
35        runtime --no-jit option is given.
36    
37    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
38        ovector, the return from the function was zero, implying that there were
39        other matches that did not fit. The correct "exactly full" value is now
40        returned.
41    
42    6.  If a subpattern that was called recursively or as a subroutine contained
43        (*PRUNE) or any other control that caused it to give a non-standard return,
44        invalid errors such as "Error -26 (nested recursion at the same subject
45        position)" or even infinite loops could occur.
46    
47    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
48        computing the minimum length on reaching *ACCEPT, and so ended up with the
49        wrong value of 1 rather than 0. Further investigation indicates that
50        computing a minimum subject length in the presence of *ACCEPT is difficult
51        (think back references, subroutine calls), and so I have changed the code
52        so that no minimum is registered for a pattern that contains *ACCEPT.
53    
54    8.  If (*THEN) was present in the first (true) branch of a conditional group,
55        it was not handled as intended.
56    
57    9.  Replaced RunTest.bat with the much improved version provided by Sheri
58        Pierce.
59    
60    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
61        the first byte in a match must be "a".
62    
63    11. Change 17 for 8.13 increased the recursion depth for patterns like
64        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
65        pattern contains any instances of (*THEN). If it does not, the old
66        optimizations are restored. It would be nice to do this on a per-group
67        basis, but at the moment that is not feasible.
68    
69    12. In some environments, the output of pcretest -C is CRLF terminated. This
70        broke RunTest's code that checks for the link size. A single white space
71        after the value is now allowed for.
72    
73    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
74        For "fr", it uses the Windows-specific input and output files.
75    
76    14. If (*THEN) appeared in a group that was called recursively or as a
77        subroutine, it did not work as intended.
78    
79    
80    Version 8.13 16-Aug-2011
81    ------------------------
82    
83    1.  The Unicode data tables have been updated to Unicode 6.0.0.
84    
85    2.  Two minor typos in pcre_internal.h have been fixed.
86    
87    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
88        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
89        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
90    
91    4.  There were a number of related bugs in the code for matching backrefences
92        caselessly in UTF-8 mode when codes for the characters concerned were
93        different numbers of bytes. For example, U+023A and U+2C65 are an upper
94        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
95        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
96        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
97        2-byte code at the end of the subject (it thought there wasn't enough data
98        left).
99    
100    5.  Comprehensive information about what went wrong is now returned by
101        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
102        as the output vector has at least 2 elements. The offset of the start of
103        the failing character and a reason code are placed in the vector.
104    
105    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
106        now returned is for the first byte of the failing character, instead of the
107        last byte inspected. This is an incompatible change, but I hope it is small
108        enough not to be a problem. It makes the returned offset consistent with
109        pcre_exec() and pcre_dfa_exec().
110    
111    7.  pcretest now gives a text phrase as well as the error number when
112        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
113        failure, the offset and reason code are output.
114    
115    8.  When \R was used with a maximizing quantifier it failed to skip backwards
116        over a \r\n pair if the subsequent match failed. Instead, it just skipped
117        back over a single character (\n). This seems wrong (because it treated the
118        two characters as a single entity when going forwards), conflicts with the
119        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
120        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
121        has been changed.
122    
123    9.  Some internal refactoring has changed the processing so that the handling
124        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
125        time (the PCRE_DOTALL option was changed this way some time ago: version
126        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
127        which was always a bit of a fudge. It also means that there is one less
128        argument for the match() function, which reduces its stack requirements
129        slightly. This change also fixes an incompatibility with Perl: the pattern
130        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
131    
132    10. More internal refactoring has drastically reduced the number of recursive
133        calls to match() for possessively repeated groups such as (abc)++ when
134        using pcre_exec().
135    
136    11. While implementing 10, a number of bugs in the handling of groups were
137        discovered and fixed:
138    
139        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
140        (a|)*(?1) gave a compile-time internal error.
141        ((a|)+)+  did not notice that the outer group could match an empty string.
142        (^a|^)+   was not marked as anchored.
143        (.*a|.*)+ was not marked as matching at start or after a newline.
144    
145    12. Yet more internal refactoring has removed another argument from the match()
146        function. Special calls to this function are now indicated by setting a
147        value in a variable in the "match data" data block.
148    
149    13. Be more explicit in pcre_study() instead of relying on "default" for
150        opcodes that mean there is no starting character; this means that when new
151        ones are added and accidentally left out of pcre_study(), testing should
152        pick them up.
153    
154    14. The -s option of pcretest has been documented for ages as being an old
155        synonym of -m (show memory usage). I have changed it to mean "force study
156        for every regex", that is, assume /S for every regex. This is similar to -i
157        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
158        using it. It makes it easier to run collections of tests with and without
159        study enabled, and thereby test pcre_study() more easily. All the standard
160        tests are now run with and without -s (but some patterns can be marked as
161        "never study" - see 20 below).
162    
163    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
164        restoration of the capturing data to the outer values was not happening
165        correctly.
166    
167    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
168        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
169        pattern had matched an empty string, and so incorrectly returned a no
170        match.
171    
172    17. There was optimizing code for the last branch of non-capturing parentheses,
173        and also for the obeyed branch of a conditional subexpression, which used
174        tail recursion to cut down on stack usage. Unfortunately, now that there is
175        the possibility of (*THEN) occurring in these branches, tail recursion is
176        no longer possible because the return has to be checked for (*THEN). These
177        two optimizations have therefore been removed. [But see 8.20/11 above.]
178    
179    18. If a pattern containing \R was studied, it was assumed that \R always
180        matched two bytes, thus causing the minimum subject length to be
181        incorrectly computed because \R can also match just one byte.
182    
183    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
184        was incorrectly computed.
185    
186    20. If /S is present twice on a test pattern in pcretest input, it now
187        *disables* studying, thereby overriding the use of -s on the command line
188        (see 14 above). This is necessary for one or two tests to keep the output
189        identical in both cases.
190    
191    21. When (*ACCEPT) was used in an assertion that matched an empty string and
192        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
193    
194    22. When an atomic group that contained a capturing parenthesis was
195        successfully matched, but the branch in which it appeared failed, the
196        capturing was not being forgotten if a higher numbered group was later
197        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
198        group 1 to "a", when in fact it should be unset. This applied to multi-
199        branched capturing and non-capturing groups, repeated or not, and also to
200        positive assertions (capturing in negative assertions does not happen
201        in PCRE) and also to nested atomic groups.
202    
203    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
204        subject after a captured substring, to make it easier to tell which of a
205        number of identical substrings has been captured.
206    
207    24. The way atomic groups are processed by pcre_exec() has been changed so that
208        if they are repeated, backtracking one repetition now resets captured
209        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
210        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
211        "aaa". Previously, it would have been "a". As part of this code
212        refactoring, the way recursive calls are handled has also been changed.
213    
214    25. If an assertion condition captured any substrings, they were not passed
215        back unless some other capturing happened later. For example, if
216        (?(?=(a))a) was matched against "a", no capturing was returned.
217    
218    26. When studying a pattern that contained subroutine calls or assertions,
219        the code for finding the minimum length of a possible match was handling
220        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
221        group 1 called group 2 while simultaneously a separate group 2 called group
222        1). A stack overflow occurred in this case. I have fixed this by limiting
223        the recursion depth to 10.
224    
225    27. Updated RunTest.bat in the distribution to the version supplied by Tom
226        Fortmann. This supports explicit test numbers on the command line, and has
227        argument validation and error reporting.
228    
229    28. An instance of \X with an unlimited repeat could fail if at any point the
230        first character it looked at was a mark character.
231    
232    29. Some minor code refactoring concerning Unicode properties and scripts
233        should reduce the stack requirement of match() slightly.
234    
235    30. Added the '=' option to pcretest to check the setting of unused capturing
236        slots at the end of the pattern, which are documented as being -1, but are
237        not included in the return count.
238    
239    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
240        compiled something random. Now it gives a compile-time error (as does
241        Perl).
242    
243    32. A *MARK encountered during the processing of a positive assertion is now
244        recorded and passed back (compatible with Perl).
245    
246    33. If --only-matching or --colour was set on a pcregrep call whose pattern
247        had alternative anchored branches, the search for a second match in a line
248        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
249        matched the line "0102" twice. The same bug affected patterns that started
250        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
251        twice.
252    
253    34. Previously, PCRE did not allow quantification of assertions. However, Perl
254        does, and because of capturing effects, quantifying parenthesized
255        assertions may at times be useful. Quantifiers are now allowed for
256        parenthesized assertions.
257    
258    35. A minor code tidy in pcre_compile() when checking options for \R usage.
259    
260    36. \g was being checked for fancy things in a character class, when it should
261        just be a literal "g".
262    
263    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
264        appearance of a nested POSIX class supersedes an apparent external class.
265        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
266        unescaped square brackets may also appear as part of class names. For
267        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
268        more like Perl. (But see 8.20/1 above.)
269    
270    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
271        was because it thought it was \N{name}, which is not supported).
272    
273    39. Add minix to OS list not supporting the -S option in pcretest.
274    
275    40. PCRE tries to detect cases of infinite recursion at compile time, but it
276        cannot analyze patterns in sufficient detail to catch mutual recursions
277        such as ((?1))((?2)). There is now a runtime test that gives an error if a
278        subgroup is called recursively as a subpattern for a second time at the
279        same position in the subject string. In previous releases this might have
280        been caught by the recursion limit, or it might have run out of stack.
281    
282    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
283        happen only once. PCRE was, however incorrectly giving a compile time error
284        "recursive call could loop indefinitely" because it cannot analyze the
285        pattern in sufficient detail. The compile time test no longer happens when
286        PCRE is compiling a conditional subpattern, but actual runaway loops are
287        now caught at runtime (see 40 above).
288    
289    42. It seems that Perl allows any characters other than a closing parenthesis
290        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
291        has been changed to be the same.
292    
293    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
294        as not to get warnings when autogen.sh is called. Also changed
295        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
296    
297    44. To help people who use pcregrep to scan files containing exceedingly long
298        lines, the following changes have been made:
299    
300        (a) The default value of the buffer size parameter has been increased from
301            8K to 20K. (The actual buffer used is three times this size.)
302    
303        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
304            PCRE is built.
305    
306        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
307            to be set at run time.
308    
309        (d) Numerical values in pcregrep options can be followed by K or M, for
310            example --buffer-size=50K.
311    
312        (e) If a line being scanned overflows pcregrep's buffer, an error is now
313            given and the return code is set to 2.
314    
315    45. Add a pointer to the latest mark to the callout data block.
316    
317    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
318        partial match of an empty string instead of no match. This was specific to
319        the use of ".".
320    
321    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
322        complete match instead of a partial match. This bug was dependent on both
323        the PCRE_UTF8 and PCRE_DOTALL options being set.
324    
325    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
326        starting byte set, because \b was not being ignored.
327    
328    
329    Version 8.12 15-Jan-2011
330    ------------------------
331    
332    1.  Fixed some typos in the markup of the man pages, and wrote a script that
333        checks for such things as part of the documentation building process.
334    
335    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
336        --match-limit and --recursion-limit options (added for 8.11). In
337        particular, this made one of the standard tests fail. (The integer value
338        went into the wrong half of a long int.)
339    
340    3.  If the --colour option was given to pcregrep with -v (invert match), it
341        did strange things, either producing crazy output, or crashing. It should,
342        of course, ignore a request for colour when reporting lines that do not
343        match.
344    
345    4.  Another pcregrep bug caused similar problems if --colour was specified with
346        -M (multiline) and the pattern match finished with a line ending.
347    
348    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
349        matched in multiline mode, the following line was shown as part of the
350        match. This seems wrong, so I have changed it.
351    
352    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
353        the check for further matches in the same line (so they could be coloured)
354        to overrun the end of the current line. If another match was found, it was
355        incorrectly shown (and then shown again when found in the next line).
356    
357    7.  If pcregrep was compiled under Windows, there was a reference to the
358        function pcregrep_exit() before it was defined. I am assuming this was
359        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
360        reported by a user. I've moved the definition above the reference.
361    
362    
363    Version 8.11 10-Dec-2010
364    ------------------------
365    
366    1.  (*THEN) was not working properly if there were untried alternatives prior
367        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
368        backtracked to try for "b" instead of moving to the next alternative branch
369        at the same level (in this case, to look for "c"). The Perl documentation
370        is clear that when (*THEN) is backtracked onto, it goes to the "next
371        alternative in the innermost enclosing group".
372    
373    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
374        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
375        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
376        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
377        (*THEN).
378    
379    3.  If \s appeared in a character class, it removed the VT character from
380        the class, even if it had been included by some previous item, for example
381        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
382        of \s, but is part of the POSIX "space" class.)
383    
384    4.  A partial match never returns an empty string (because you can always
385        match an empty string at the end of the subject); however the checking for
386        an empty string was starting at the "start of match" point. This has been
387        changed to the "earliest inspected character" point, because the returned
388        data for a partial match starts at this character. This means that, for
389        example, /(?<=abc)def/ gives a partial match for the subject "abc"
390        (previously it gave "no match").
391    
392    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
393        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
394        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
395        has an implication that the given string is incomplete (because a partial
396        match is preferred over a full match). For this reason, these items now
397        give a partial match in this situation. [Aside: previously, the one case
398        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
399        match rather than a full match, which was wrong by the old rules, but is
400        now correct.]
401    
402    6.  There was a bug in the handling of #-introduced comments, recognized when
403        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
404        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
405        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
406        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
407        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
408        places in pcre_compile().
409    
410    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
411        comments when looking ahead for named forward references to subpatterns,
412        the only newline sequence it recognized was NL. It now handles newlines
413        according to the set newline convention.
414    
415    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
416        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
417        cater for a lack of strerror(). These oversights have been fixed.
418    
419    9.  Added --match-limit and --recursion-limit to pcregrep.
420    
421    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
422    
423    11. When the -o option was used, pcregrep was setting a return code of 1, even
424        when matches were found, and --line-buffered was not being honoured.
425    
426    12. Added an optional parentheses number to the -o and --only-matching options
427        of pcregrep.
428    
429    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
430        can match an empty string. The code to do it in pcretest and pcredemo
431        needed fixing:
432    
433        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
434            only one byte after an empty string match just before CRLF (this case
435            just got forgotten; "any" and "anycrlf" were OK).
436    
437        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
438            mode when an empty string match preceded an ASCII character followed by
439            a non-ASCII character. (The code for advancing by one character rather
440            than one byte was nonsense.)
441    
442        (c) The pcredemo.c sample program did not have any code at all to handle
443            the cases when CRLF is a valid newline sequence.
444    
445    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
446        as a starting offset was within the subject string. There is now a new
447        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
448        negative or greater than the length of the string. In order to test this,
449        pcretest is extended to allow the setting of negative starting offsets.
450    
451    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
452        starting offset points to the beginning of a UTF-8 character was
453        unnecessarily clumsy. I tidied it up.
454    
455    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
456        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
457    
458    17. Nobody had reported that the --include_dir option, which was added in
459        release 7.7 should have been called --include-dir (hyphen, not underscore)
460        for compatibility with GNU grep. I have changed it to --include-dir, but
461        left --include_dir as an undocumented synonym, and the same for
462        --exclude-dir, though that is not available in GNU grep, at least as of
463        release 2.5.4.
464    
465    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
466        characters from a string of bytes) have been redefined so as not to use
467        loops, in order to improve performance in some environments. At the same
468        time, I abstracted some of the common code into auxiliary macros to save
469        repetition (this should not affect the compiled code).
470    
471    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
472        compile-time error is now given if \c is not followed by an ASCII
473        character, that is, a byte less than 128. (In EBCDIC mode, the code is
474        different, and any byte value is allowed.)
475    
476    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
477        START_OPTIMIZE option, which is now allowed at compile time - but just
478        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
479        to pcregrep and other applications that have no direct access to PCRE
480        options. The new /Y option in pcretest sets this option when calling
481        pcre_compile().
482    
483    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
484        back references. Groups containing recursive back references were forced to
485        be atomic by that change, but in the case of named groups, the amount of
486        memory required was incorrectly computed, leading to "Failed: internal
487        error: code overflow". This has been fixed.
488    
489    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
490        pcretest.c, to avoid build problems in some Borland environments.
491    
492    
493    Version 8.10 25-Jun-2010
494    ------------------------
495    
496    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
497        THEN.
498    
499    2.  (*ACCEPT) was not working when inside an atomic group.
500    
501    3.  Inside a character class, \B is treated as a literal by default, but
502        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
503        causes the error). The code is unchanged, but I tidied the documentation.
504    
505    4.  Inside a character class, PCRE always treated \R and \X as literals,
506        whereas Perl faults them if its -w option is set. I have changed PCRE so
507        that it faults them when PCRE_EXTRA is set.
508    
509    5.  Added support for \N, which always matches any character other than
510        newline. (It is the same as "." when PCRE_DOTALL is not set.)
511    
512    6.  When compiling pcregrep with newer versions of gcc which may have
513        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
514        declared with attribute warn_unused_result" were given. Just casting the
515        result to (void) does not stop the warnings; a more elaborate fudge is
516        needed. I've used a macro to implement this.
517    
518    7.  Minor change to pcretest.c to avoid a compiler warning.
519    
520    8.  Added four artifical Unicode properties to help with an option to make
521        \s etc use properties (see next item). The new properties are: Xan
522        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
523    
524    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
525        use Unicode properties. (*UCP) at the start of a pattern can be used to set
526        this option. Modified pcretest to add /W to test this facility. Added
527        REG_UCP to make it available via the POSIX interface.
528    
529    10. Added --line-buffered to pcregrep.
530    
531    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
532        studied, and the match started with a letter with a code point greater than
533        127 whose first byte was different to the first byte of the other case of
534        the letter, the other case of this starting letter was not recognized
535        (#976).
536    
537    12. If a pattern that was studied started with a repeated Unicode property
538        test, for example, \p{Nd}+, there was the theoretical possibility of
539        setting up an incorrect bitmap of starting bytes, but fortunately it could
540        not have actually happened in practice until change 8 above was made (it
541        added property types that matched character-matching opcodes).
542    
543    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
544        possible starting bytes for non-anchored patterns.
545    
546    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
547        \R, and also a number of cases that involve Unicode properties, both
548        explicit and implicit when PCRE_UCP is set.
549    
550    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
551        input, it could crash or give wrong results if characters with values
552        greater than 0xc0 were present in the subject string. (Detail: it assumed
553        UTF-8 input when processing these items.)
554    
555    16. Added a lot of (int) casts to avoid compiler warnings in systems where
556        size_t is 64-bit (#991).
557    
558    17. Added a check for running out of memory when PCRE is compiled with
559        --disable-stack-for-recursion (#990).
560    
561    18. If the last data line in a file for pcretest does not have a newline on
562        the end, a newline was missing in the output.
563    
564    19. The default pcre_chartables.c file recognizes only ASCII characters (values
565        less than 128) in its various bitmaps. However, there is a facility for
566        generating tables according to the current locale when PCRE is compiled. It
567        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
568        characters, are recognized by isspace() and therefore were getting set in
569        these tables, and indeed these tables seem to approximate to ISO 8859. This
570        caused a problem in UTF-8 mode when pcre_study() was used to create a list
571        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
572        which of course cannot start UTF-8 characters. I have changed the code so
573        that only real ASCII characters (less than 128) and the correct starting
574        bytes for UTF-8 encodings are set for characters greater than 127 when in
575        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
576        altogether.)
577    
578    20. Added the /T option to pcretest so as to be able to run tests with non-
579        standard character tables, thus making it possible to include the tests
580        used for 19 above in the standard set of tests.
581    
582    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
583        reference to a subpattern the other side of a comment that contains an
584        opening parenthesis caused either an internal compiling error, or a
585        reference to the wrong subpattern.
586    
587    
588    Version 8.02 19-Mar-2010
589    ------------------------
590    
591    1.  The Unicode data tables have been updated to Unicode 5.2.0.
592    
593    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
594        configured.
595    
596    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
597        original author of that file, following a query about its status.
598    
599    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
600        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
601    
602    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
603        quantifier applied to a forward-referencing subroutine call, could compile
604        incorrect code or give the error "internal error: previously-checked
605        referenced subpattern not found".
606    
607    6.  Both MS Visual Studio and Symbian OS have problems with initializing
608        variables to point to external functions. For these systems, therefore,
609        pcre_malloc etc. are now initialized to local functions that call the
610        relevant global functions.
611    
612    7.  There were two entries missing in the vectors called coptable and poptable
613        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
614        I've fixed the data, and added a kludgy way of testing at compile time that
615        the lengths are correct (equal to the number of opcodes).
616    
617    8.  Following on from 7, I added a similar kludge to check the length of the
618        eint vector in pcreposix.c.
619    
620    9.  Error texts for pcre_compile() are held as one long string to avoid too
621        much relocation at load time. To find a text, the string is searched,
622        counting zeros. There was no check for running off the end of the string,
623        which could happen if a new error number was added without updating the
624        string.
625    
626    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
627    
628    11. \K was not working if it appeared in an atomic group or in a group that
629        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
630        \K is "not well defined" if used in an assertion. PCRE now accepts it if
631        the assertion is positive, but not if it is negative.
632    
633    12. Change 11 fortuitously reduced the size of the stack frame used in the
634        "match()" function of pcre_exec.c by one pointer. Forthcoming
635        implementation of support for (*MARK) will need an extra pointer on the
636        stack; I have reserved it now, so that the stack frame size does not
637        decrease.
638    
639    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
640        item in branch that calls a recursion is a subroutine call - as in the
641        second branch in the above example - was incorrectly given the compile-
642        time error "recursive call could loop indefinitely" because pcre_compile()
643        was not correctly checking the subroutine for matching a non-empty string.
644    
645    14. The checks for overrunning compiling workspace could trigger after an
646        overrun had occurred. This is a "should never occur" error, but it can be
647        triggered by pathological patterns such as hundreds of nested parentheses.
648        The checks now trigger 100 bytes before the end of the workspace.
649    
650    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
651    
652    
653    Version 8.01 19-Jan-2010
654    ------------------------
655    
656    1.  If a pattern contained a conditional subpattern with only one branch (in
657        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
658        computed the wrong minimum data length (which is of course zero for such
659        subpatterns). This could cause incorrect "no match" results.
660    
661    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
662        the pattern is reset in the first branch, pcre_compile() failed with
663        "internal error: code overflow at offset...". This happened only when
664        the reset was to the original external option setting. (An optimization
665        abstracts leading options settings into an external setting, which was the
666        cause of this.)
667    
668    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
669        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
670        assertion pattern did not match (meaning that the assertion was true), it
671        was incorrectly treated as false if the SKIP had been reached during the
672        matching. This also applied to assertions used as conditions.
673    
674    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
675        assertion subpattern, including such a pattern used as a condition,
676        unpredictable results occurred, instead of the error return
677        PCRE_ERROR_DFA_UITEM.
678    
679    5.  The C++ GlobalReplace function was not working like Perl for the special
680        situation when an empty string is matched. It now does the fancy magic
681        stuff that is necessary.
682    
683    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
684        removed. (These were left over from very, very early versions of PCRE.)
685    
686    7.  Some cosmetic changes to the code to make life easier when compiling it
687        as part of something else:
688    
689        (a) Change DEBUG to PCRE_DEBUG.
690    
691        (b) In pcre_compile(), rename the member of the "branch_chain" structure
692            called "current" as "current_branch", to prevent a collision with the
693            Linux macro when compiled as a kernel module.
694    
695        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
696            prevent a collision with the Linux macro when compiled as a kernel
697            module.
698    
699    8.  In pcre_compile() there are some checks for integer overflows that used to
700        cast potentially large values to (double). This has been changed to that
701        when building, a check for int64_t is made, and if it is found, it is used
702        instead, thus avoiding the use of floating point arithmetic. (There is no
703        other use of FP in PCRE.) If int64_t is not found, the fallback is to
704        double.
705    
706    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
707        2005 (difference between two addresses compared to an unsigned value).
708    
709    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
710        custom one, because of the following reported problem in Windows:
711    
712          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
713              under Win32.
714          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
715              therefore missing the function definition.
716          - The compiler thus generates a "C" signature for the test function.
717          - The linker fails to find the "C" function.
718          - PCRE fails to configure if asked to do so against libbz2.
719    
720    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
721        messages were output:
722    
723          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
724          rerunning libtoolize, to keep the correct libtool macros in-tree.
725          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
726    
727        I have done both of these things.
728    
729    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
730        most of the time, it *can* run out if it is given a pattern that contains a
731        runaway infinite recursion. I updated the discussion in the pcrestack man
732        page.
733    
734    13. Now that we have gone to the x.xx style of version numbers, the minor
735        version may start with zero. Using 08 or 09 is a bad idea because users
736        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
737        interpreted as invalid octal numbers. I've updated the previous comment in
738        configure.ac, and also added a check that gives an error if 08 or 09 are
739        used.
740    
741    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
742        causing partial matching to fail when the end of the subject matched \W
743        in a UTF-8 pattern where \W was quantified with a minimum of 3.
744    
745    15. There were some discrepancies between the declarations in pcre_internal.h
746        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
747        their definitions. The declarations used "const uschar *" and the
748        definitions used USPTR. Even though USPTR is normally defined as "const
749        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
750        reported that: "This difference in casting confuses some C++ compilers, for
751        example, SunCC recognizes above declarations as different functions and
752        generates broken code for hbpcre." I have changed the declarations to use
753        USPTR.
754    
755    16. GNU libtool is named differently on some systems. The autogen.sh script now
756        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
757        (FreeBSD).
758    
759    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
760        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
761        comment: "Figure out how to create a longlong from a string: strtoll and
762        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
763        instance, but it only takes 2 args instead of 3!"
764    
765    18. A subtle bug concerned with back references has been fixed by a change of
766        specification, with a corresponding code fix. A pattern such as
767        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
768        refers, was giving matches when it shouldn't. For example, xa=xaaa would
769        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
770        same bug. Such groups have to be quantified to be useful, or contained
771        inside another quantified group. (If there's no repetition, the reference
772        can never match.) The problem arises because, having left the group and
773        moved on to the rest of the pattern, a later failure that backtracks into
774        the group uses the captured value from the final iteration of the group
775        rather than the correct earlier one. I have fixed this in PCRE by forcing
776        any group that contains a reference to itself to be an atomic group; that
777        is, there cannot be any backtracking into it once it has completed. This is
778        similar to recursive and subroutine calls.
779    
780    
781    Version 8.00 19-Oct-09
782  ----------------------  ----------------------
783    
784  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
785      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
786      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
787      error.      error.
788    
789  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
790      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
791      in a Windows environment.      in a Windows environment.
792    
793  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
794      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
795      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
796      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
797      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
798      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
799      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
800    
801    4.  The long form of the pcregrep -F option was incorrectly implemented as
802        --fixed_strings instead of --fixed-strings. This is an incompatible change,
803        but it seems right to fix it, and I didn't think it was worth preserving
804        the old behaviour.
805    
806    5.  The command line items --regex=pattern and --regexp=pattern were not
807        recognized by pcregrep, which required --regex pattern or --regexp pattern
808        (with a space rather than an '='). The man page documented the '=' forms,
809        which are compatible with GNU grep; these now work.
810    
811    6.  No libpcreposix.pc file was created for pkg-config; there was just
812        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
813    
814    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
815        when UCP support is not needed, by modifying the Python script that
816        generates it from Unicode data files. This should not matter if the module
817        is correctly used as a library, but I received one complaint about 50K of
818        unwanted data. My guess is that the person linked everything into his
819        program rather than using a library. Anyway, it does no harm.
820    
821    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
822        was a minimum greater than 1 for a wide character in a possessive
823        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
824        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
825        character. Chaos in the form of incorrect output or a compiling loop could
826        result.
827    
828    9.  The restrictions on what a pattern can contain when partial matching is
829        requested for pcre_exec() have been removed. All patterns can now be
830        partially matched by this function. In addition, if there are at least two
831        slots in the offset vector, the offset of the earliest inspected character
832        for the match and the offset of the end of the subject are set in them when
833        PCRE_ERROR_PARTIAL is returned.
834    
835    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
836        synonymous with PCRE_PARTIAL, for backwards compatibility, and
837        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
838        and may be more useful for multi-segment matching.
839    
840    11. Partial matching with pcre_exec() is now more intuitive. A partial match
841        used to be given if ever the end of the subject was reached; now it is
842        given only if matching could not proceed because another character was
843        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
844        string "Z", which now yields "no match" instead of "partial match". In the
845        case of pcre_dfa_exec(), "no match" is given if every matching path for the
846        final character ended with (*FAIL).
847    
848    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
849        if the pattern had a "must contain" character that was already found in the
850        earlier partial match, unless partial matching was again requested. For
851        example, with the pattern /dog.(body)?/, the "must contain" character is
852        "g". If the first part-match was for the string "dog", restarting with
853        "sbody" failed. This bug has been fixed.
854    
855    13. The string returned by pcre_dfa_exec() after a partial match has been
856        changed so that it starts at the first inspected character rather than the
857        first character of the match. This makes a difference only if the pattern
858        starts with a lookbehind assertion or \b or \B (\K is not supported by
859        pcre_dfa_exec()). It's an incompatible change, but it makes the two
860        matching functions compatible, and I think it's the right thing to do.
861    
862    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
863        so that the demonstration program is easily available in environments where
864        PCRE has not been installed from source.
865    
866    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
867        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
868        library.
869    
870    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
871        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
872        is not the first non-POSIX option to be added. Clearly some people find
873        these options useful.
874    
875    17. If a caller to the POSIX matching function regexec() passes a non-zero
876        value for nmatch with a NULL value for pmatch, the value of
877        nmatch is forced to zero.
878    
879    18. RunGrepTest did not have a test for the availability of the -u option of
880        the diff command, as RunTest does. It now checks in the same way as
881        RunTest, and also checks for the -b option.
882    
883    19. If an odd number of negated classes containing just a single character
884        interposed, within parentheses, between a forward reference to a named
885        subpattern and the definition of the subpattern, compilation crashed with
886        an internal error, complaining that it could not find the referenced
887        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
888        [The bug was that it was starting one character too far in when skipping
889        over the character class, thus treating the ] as data rather than
890        terminating the class. This meant it could skip too much.]
891    
892    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
893        /g option in pcretest when the pattern contains \K, which makes it possible
894        to have an empty string match not at the start, even when the pattern is
895        anchored. Updated pcretest and pcredemo to use this option.
896    
897    21. If the maximum number of capturing subpatterns in a recursion was greater
898        than the maximum at the outer level, the higher number was returned, but
899        with unset values at the outer level. The correct (outer level) value is
900        now given.
901    
902    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
903        PCRE did not set those parentheses (unlike Perl). I have now found a way to
904        make it do so. The string so far is captured, making this feature
905        compatible with Perl.
906    
907    23. The tests have been re-organized, adding tests 11 and 12, to make it
908        possible to check the Perl 5.10 features against Perl 5.10.
909    
910    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
911        pattern matches a fixed length string. PCRE did not allow this; now it
912        does. Neither allows recursion.
913    
914    25. I finally figured out how to implement a request to provide the minimum
915        length of subject string that was needed in order to match a given pattern.
916        (It was back references and recursion that I had previously got hung up
917        on.) This code has now been added to pcre_study(); it finds a lower bound
918        to the length of subject needed. It is not necessarily the greatest lower
919        bound, but using it to avoid searching strings that are too short does give
920        some useful speed-ups. The value is available to calling programs via
921        pcre_fullinfo().
922    
923    26. While implementing 25, I discovered to my embarrassment that pcretest had
924        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
925        study optimizations had never been tested with that matching function.
926        Oops. What is worse, even when it was passed study data, there was a bug in
927        pcre_dfa_exec() that meant it never actually used it. Double oops. There
928        were also very few tests of studied patterns with pcre_dfa_exec().
929    
930    27. If (?| is used to create subpatterns with duplicate numbers, they are now
931        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
932        on the other side of the coin, they are no longer allowed to have different
933        names, because these cannot be distinguished in PCRE, and this has caused
934        confusion. (This is a difference from Perl.)
935    
936    28. When duplicate subpattern names are present (necessarily with different
937        numbers, as required by 27 above), and a test is made by name in a
938        conditional pattern, either for a subpattern having been matched, or for
939        recursion in such a pattern, all the associated numbered subpatterns are
940        tested, and the overall condition is true if the condition is true for any
941        one of them. This is the way Perl works, and is also more like the way
942        testing by number works.
943    
944    
945  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
946  ---------------------  ---------------------

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