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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.01 06-Jan-10  Version 8.21
5  ----------------------  ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
50    Version 8.20 21-Oct-2011
51    ------------------------
53    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
54        a POSIX class. After further experiments with Perl, which convinced me that
55        Perl has bugs and confusions, a closing square bracket is no longer allowed
56        in a POSIX name. This bug also affected patterns with classes that started
57        with full stops.
59    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
60        captured substring, but while checking the failing first alternative,
61        substring 1 is temporarily captured. If the output vector supplied to
62        pcre_exec() was not big enough for this capture, the yield of the function
63        was still zero ("insufficient space for captured substrings"). This cannot
64        be totally fixed without adding another stack variable, which seems a lot
65        of expense for a edge case. However, I have improved the situation in cases
66        such as /(a)(b)x|abc/ matched against "abc", where the return code
67        indicates that fewer than the maximum number of slots in the ovector have
68        been set.
70    3.  Related to (2) above: when there are more back references in a pattern than
71        slots in the output vector, pcre_exec() uses temporary memory during
72        matching, and copies in the captures as far as possible afterwards. It was
73        using the entire output vector, but this conflicts with the specification
74        that only 2/3 is used for passing back captured substrings. Now it uses
75        only the first 2/3, for compatibility. This is, of course, another edge
76        case.
78    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
79        main code base, and can be used by building with --enable-jit. When this is
80        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
81        runtime --no-jit option is given.
83    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
84        ovector, the return from the function was zero, implying that there were
85        other matches that did not fit. The correct "exactly full" value is now
86        returned.
88    6.  If a subpattern that was called recursively or as a subroutine contained
89        (*PRUNE) or any other control that caused it to give a non-standard return,
90        invalid errors such as "Error -26 (nested recursion at the same subject
91        position)" or even infinite loops could occur.
93    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
94        computing the minimum length on reaching *ACCEPT, and so ended up with the
95        wrong value of 1 rather than 0. Further investigation indicates that
96        computing a minimum subject length in the presence of *ACCEPT is difficult
97        (think back references, subroutine calls), and so I have changed the code
98        so that no minimum is registered for a pattern that contains *ACCEPT.
100    8.  If (*THEN) was present in the first (true) branch of a conditional group,
101        it was not handled as intended. [But see 16 below.]
103    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
104        Sheri Pierce.
106    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
107        the first byte in a match must be "a".
109    11. Change 17 for 8.13 increased the recursion depth for patterns like
110        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
111        pattern contains any instances of (*THEN). If it does not, the old
112        optimizations are restored. It would be nice to do this on a per-group
113        basis, but at the moment that is not feasible.
115    12. In some environments, the output of pcretest -C is CRLF terminated. This
116        broke RunTest's code that checks for the link size. A single white space
117        character after the value is now allowed for.
119    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
120        For "fr", it uses the Windows-specific input and output files.
122    14. If (*THEN) appeared in a group that was called recursively or as a
123        subroutine, it did not work as intended. [But see next item.]
125    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
126        pattern fragments (but not containing any | characters). If A and B are
127        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
128        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
129        D. In other words, Perl considers parentheses that do not contain any |
130        characters to be part of a surrounding alternative, whereas PCRE was
131        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
132        differently. PCRE now behaves in the same way as Perl, except in the case
133        of subroutine/recursion calls such as (?1) which have in any case always
134        been different (but PCRE had them first :-).
136    16. Related to 15 above: Perl does not treat the | in a conditional group as
137        creating alternatives. Such a group is treated in the same way as an
138        ordinary group without any | characters when processing (*THEN). PCRE has
139        been changed to match Perl's behaviour.
141    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
142        RunGrepTest script failed.
144    18. Change 22 for version 13 caused atomic groups to use more stack. This is
145        inevitable for groups that contain captures, but it can lead to a lot of
146        stack use in large patterns. The old behaviour has been restored for atomic
147        groups that do not contain any capturing parentheses.
149    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
150        suppress the check for a minimum subject length at run time. (If it was
151        given to pcre_exec() or pcre_dfa_exec() it did work.)
153    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
154        fail to work when decoding hex characters in data strings in EBCDIC
155        environments.
157    21. It appears that in at least one Mac OS environment, the isxdigit() function
158        is implemented as a macro that evaluates to its argument more than once,
159        contravening the C 90 Standard (I haven't checked a later standard). There
160        was an instance in pcretest which caused it to go wrong when processing
161        \x{...} escapes in subject strings. The has been rewritten to avoid using
162        things like p++ in the argument of isxdigit().
165    Version 8.13 16-Aug-2011
166    ------------------------
168    1.  The Unicode data tables have been updated to Unicode 6.0.0.
170    2.  Two minor typos in pcre_internal.h have been fixed.
172    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
173        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
174        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
176    4.  There were a number of related bugs in the code for matching backrefences
177        caselessly in UTF-8 mode when codes for the characters concerned were
178        different numbers of bytes. For example, U+023A and U+2C65 are an upper
179        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
180        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
181        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
182        2-byte code at the end of the subject (it thought there wasn't enough data
183        left).
185    5.  Comprehensive information about what went wrong is now returned by
186        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
187        as the output vector has at least 2 elements. The offset of the start of
188        the failing character and a reason code are placed in the vector.
190    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
191        now returned is for the first byte of the failing character, instead of the
192        last byte inspected. This is an incompatible change, but I hope it is small
193        enough not to be a problem. It makes the returned offset consistent with
194        pcre_exec() and pcre_dfa_exec().
196    7.  pcretest now gives a text phrase as well as the error number when
197        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
198        failure, the offset and reason code are output.
200    8.  When \R was used with a maximizing quantifier it failed to skip backwards
201        over a \r\n pair if the subsequent match failed. Instead, it just skipped
202        back over a single character (\n). This seems wrong (because it treated the
203        two characters as a single entity when going forwards), conflicts with the
204        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
205        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
206        has been changed.
208    9.  Some internal refactoring has changed the processing so that the handling
209        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
210        time (the PCRE_DOTALL option was changed this way some time ago: version
211        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
212        which was always a bit of a fudge. It also means that there is one less
213        argument for the match() function, which reduces its stack requirements
214        slightly. This change also fixes an incompatibility with Perl: the pattern
215        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
217    10. More internal refactoring has drastically reduced the number of recursive
218        calls to match() for possessively repeated groups such as (abc)++ when
219        using pcre_exec().
221    11. While implementing 10, a number of bugs in the handling of groups were
222        discovered and fixed:
224        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
225        (a|)*(?1) gave a compile-time internal error.
226        ((a|)+)+  did not notice that the outer group could match an empty string.
227        (^a|^)+   was not marked as anchored.
228        (.*a|.*)+ was not marked as matching at start or after a newline.
230    12. Yet more internal refactoring has removed another argument from the match()
231        function. Special calls to this function are now indicated by setting a
232        value in a variable in the "match data" data block.
234    13. Be more explicit in pcre_study() instead of relying on "default" for
235        opcodes that mean there is no starting character; this means that when new
236        ones are added and accidentally left out of pcre_study(), testing should
237        pick them up.
239    14. The -s option of pcretest has been documented for ages as being an old
240        synonym of -m (show memory usage). I have changed it to mean "force study
241        for every regex", that is, assume /S for every regex. This is similar to -i
242        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
243        using it. It makes it easier to run collections of tests with and without
244        study enabled, and thereby test pcre_study() more easily. All the standard
245        tests are now run with and without -s (but some patterns can be marked as
246        "never study" - see 20 below).
248    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
249        restoration of the capturing data to the outer values was not happening
250        correctly.
252    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
253        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
254        pattern had matched an empty string, and so incorrectly returned a no
255        match.
257    17. There was optimizing code for the last branch of non-capturing parentheses,
258        and also for the obeyed branch of a conditional subexpression, which used
259        tail recursion to cut down on stack usage. Unfortunately, now that there is
260        the possibility of (*THEN) occurring in these branches, tail recursion is
261        no longer possible because the return has to be checked for (*THEN). These
262        two optimizations have therefore been removed. [But see 8.20/11 above.]
264    18. If a pattern containing \R was studied, it was assumed that \R always
265        matched two bytes, thus causing the minimum subject length to be
266        incorrectly computed because \R can also match just one byte.
268    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
269        was incorrectly computed.
271    20. If /S is present twice on a test pattern in pcretest input, it now
272        *disables* studying, thereby overriding the use of -s on the command line
273        (see 14 above). This is necessary for one or two tests to keep the output
274        identical in both cases.
276    21. When (*ACCEPT) was used in an assertion that matched an empty string and
277        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
279    22. When an atomic group that contained a capturing parenthesis was
280        successfully matched, but the branch in which it appeared failed, the
281        capturing was not being forgotten if a higher numbered group was later
282        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
283        group 1 to "a", when in fact it should be unset. This applied to multi-
284        branched capturing and non-capturing groups, repeated or not, and also to
285        positive assertions (capturing in negative assertions does not happen
286        in PCRE) and also to nested atomic groups.
288    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
289        subject after a captured substring, to make it easier to tell which of a
290        number of identical substrings has been captured.
292    24. The way atomic groups are processed by pcre_exec() has been changed so that
293        if they are repeated, backtracking one repetition now resets captured
294        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
295        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
296        "aaa". Previously, it would have been "a". As part of this code
297        refactoring, the way recursive calls are handled has also been changed.
299    25. If an assertion condition captured any substrings, they were not passed
300        back unless some other capturing happened later. For example, if
301        (?(?=(a))a) was matched against "a", no capturing was returned.
303    26. When studying a pattern that contained subroutine calls or assertions,
304        the code for finding the minimum length of a possible match was handling
305        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
306        group 1 called group 2 while simultaneously a separate group 2 called group
307        1). A stack overflow occurred in this case. I have fixed this by limiting
308        the recursion depth to 10.
310    27. Updated RunTest.bat in the distribution to the version supplied by Tom
311        Fortmann. This supports explicit test numbers on the command line, and has
312        argument validation and error reporting.
314    28. An instance of \X with an unlimited repeat could fail if at any point the
315        first character it looked at was a mark character.
317    29. Some minor code refactoring concerning Unicode properties and scripts
318        should reduce the stack requirement of match() slightly.
320    30. Added the '=' option to pcretest to check the setting of unused capturing
321        slots at the end of the pattern, which are documented as being -1, but are
322        not included in the return count.
324    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
325        compiled something random. Now it gives a compile-time error (as does
326        Perl).
328    32. A *MARK encountered during the processing of a positive assertion is now
329        recorded and passed back (compatible with Perl).
331    33. If --only-matching or --colour was set on a pcregrep call whose pattern
332        had alternative anchored branches, the search for a second match in a line
333        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
334        matched the line "0102" twice. The same bug affected patterns that started
335        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
336        twice.
338    34. Previously, PCRE did not allow quantification of assertions. However, Perl
339        does, and because of capturing effects, quantifying parenthesized
340        assertions may at times be useful. Quantifiers are now allowed for
341        parenthesized assertions.
343    35. A minor code tidy in pcre_compile() when checking options for \R usage.
345    36. \g was being checked for fancy things in a character class, when it should
346        just be a literal "g".
348    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
349        appearance of a nested POSIX class supersedes an apparent external class.
350        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
351        unescaped square brackets may also appear as part of class names. For
352        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
353        more like Perl. (But see 8.20/1 above.)
355    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
356        was because it thought it was \N{name}, which is not supported).
358    39. Add minix to OS list not supporting the -S option in pcretest.
360    40. PCRE tries to detect cases of infinite recursion at compile time, but it
361        cannot analyze patterns in sufficient detail to catch mutual recursions
362        such as ((?1))((?2)). There is now a runtime test that gives an error if a
363        subgroup is called recursively as a subpattern for a second time at the
364        same position in the subject string. In previous releases this might have
365        been caught by the recursion limit, or it might have run out of stack.
367    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
368        happen only once. PCRE was, however incorrectly giving a compile time error
369        "recursive call could loop indefinitely" because it cannot analyze the
370        pattern in sufficient detail. The compile time test no longer happens when
371        PCRE is compiling a conditional subpattern, but actual runaway loops are
372        now caught at runtime (see 40 above).
374    42. It seems that Perl allows any characters other than a closing parenthesis
375        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
376        has been changed to be the same.
378    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
379        as not to get warnings when autogen.sh is called. Also changed
380        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
382    44. To help people who use pcregrep to scan files containing exceedingly long
383        lines, the following changes have been made:
385        (a) The default value of the buffer size parameter has been increased from
386            8K to 20K. (The actual buffer used is three times this size.)
388        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
389            PCRE is built.
391        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
392            to be set at run time.
394        (d) Numerical values in pcregrep options can be followed by K or M, for
395            example --buffer-size=50K.
397        (e) If a line being scanned overflows pcregrep's buffer, an error is now
398            given and the return code is set to 2.
400    45. Add a pointer to the latest mark to the callout data block.
402    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
403        partial match of an empty string instead of no match. This was specific to
404        the use of ".".
406    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
407        complete match instead of a partial match. This bug was dependent on both
408        the PCRE_UTF8 and PCRE_DOTALL options being set.
410    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
411        starting byte set, because \b was not being ignored.
414    Version 8.12 15-Jan-2011
415    ------------------------
417    1.  Fixed some typos in the markup of the man pages, and wrote a script that
418        checks for such things as part of the documentation building process.
420    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
421        --match-limit and --recursion-limit options (added for 8.11). In
422        particular, this made one of the standard tests fail. (The integer value
423        went into the wrong half of a long int.)
425    3.  If the --colour option was given to pcregrep with -v (invert match), it
426        did strange things, either producing crazy output, or crashing. It should,
427        of course, ignore a request for colour when reporting lines that do not
428        match.
430    4.  Another pcregrep bug caused similar problems if --colour was specified with
431        -M (multiline) and the pattern match finished with a line ending.
433    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
434        matched in multiline mode, the following line was shown as part of the
435        match. This seems wrong, so I have changed it.
437    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
438        the check for further matches in the same line (so they could be coloured)
439        to overrun the end of the current line. If another match was found, it was
440        incorrectly shown (and then shown again when found in the next line).
442    7.  If pcregrep was compiled under Windows, there was a reference to the
443        function pcregrep_exit() before it was defined. I am assuming this was
444        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
445        reported by a user. I've moved the definition above the reference.
448    Version 8.11 10-Dec-2010
449    ------------------------
451    1.  (*THEN) was not working properly if there were untried alternatives prior
452        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
453        backtracked to try for "b" instead of moving to the next alternative branch
454        at the same level (in this case, to look for "c"). The Perl documentation
455        is clear that when (*THEN) is backtracked onto, it goes to the "next
456        alternative in the innermost enclosing group".
458    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
459        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
460        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
461        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
462        (*THEN).
464    3.  If \s appeared in a character class, it removed the VT character from
465        the class, even if it had been included by some previous item, for example
466        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
467        of \s, but is part of the POSIX "space" class.)
469    4.  A partial match never returns an empty string (because you can always
470        match an empty string at the end of the subject); however the checking for
471        an empty string was starting at the "start of match" point. This has been
472        changed to the "earliest inspected character" point, because the returned
473        data for a partial match starts at this character. This means that, for
474        example, /(?<=abc)def/ gives a partial match for the subject "abc"
475        (previously it gave "no match").
477    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
478        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
479        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
480        has an implication that the given string is incomplete (because a partial
481        match is preferred over a full match). For this reason, these items now
482        give a partial match in this situation. [Aside: previously, the one case
483        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
484        match rather than a full match, which was wrong by the old rules, but is
485        now correct.]
487    6.  There was a bug in the handling of #-introduced comments, recognized when
488        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
489        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
490        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
491        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
492        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
493        places in pcre_compile().
495    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
496        comments when looking ahead for named forward references to subpatterns,
497        the only newline sequence it recognized was NL. It now handles newlines
498        according to the set newline convention.
500    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
501        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
502        cater for a lack of strerror(). These oversights have been fixed.
504    9.  Added --match-limit and --recursion-limit to pcregrep.
506    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
508    11. When the -o option was used, pcregrep was setting a return code of 1, even
509        when matches were found, and --line-buffered was not being honoured.
511    12. Added an optional parentheses number to the -o and --only-matching options
512        of pcregrep.
514    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
515        can match an empty string. The code to do it in pcretest and pcredemo
516        needed fixing:
518        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
519            only one byte after an empty string match just before CRLF (this case
520            just got forgotten; "any" and "anycrlf" were OK).
522        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
523            mode when an empty string match preceded an ASCII character followed by
524            a non-ASCII character. (The code for advancing by one character rather
525            than one byte was nonsense.)
527        (c) The pcredemo.c sample program did not have any code at all to handle
528            the cases when CRLF is a valid newline sequence.
530    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
531        as a starting offset was within the subject string. There is now a new
532        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
533        negative or greater than the length of the string. In order to test this,
534        pcretest is extended to allow the setting of negative starting offsets.
536    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
537        starting offset points to the beginning of a UTF-8 character was
538        unnecessarily clumsy. I tidied it up.
540    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
541        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
543    17. Nobody had reported that the --include_dir option, which was added in
544        release 7.7 should have been called --include-dir (hyphen, not underscore)
545        for compatibility with GNU grep. I have changed it to --include-dir, but
546        left --include_dir as an undocumented synonym, and the same for
547        --exclude-dir, though that is not available in GNU grep, at least as of
548        release 2.5.4.
550    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
551        characters from a string of bytes) have been redefined so as not to use
552        loops, in order to improve performance in some environments. At the same
553        time, I abstracted some of the common code into auxiliary macros to save
554        repetition (this should not affect the compiled code).
556    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
557        compile-time error is now given if \c is not followed by an ASCII
558        character, that is, a byte less than 128. (In EBCDIC mode, the code is
559        different, and any byte value is allowed.)
561    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
562        START_OPTIMIZE option, which is now allowed at compile time - but just
563        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
564        to pcregrep and other applications that have no direct access to PCRE
565        options. The new /Y option in pcretest sets this option when calling
566        pcre_compile().
568    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
569        back references. Groups containing recursive back references were forced to
570        be atomic by that change, but in the case of named groups, the amount of
571        memory required was incorrectly computed, leading to "Failed: internal
572        error: code overflow". This has been fixed.
574    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
575        pcretest.c, to avoid build problems in some Borland environments.
578    Version 8.10 25-Jun-2010
579    ------------------------
581    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
582        THEN.
584    2.  (*ACCEPT) was not working when inside an atomic group.
586    3.  Inside a character class, \B is treated as a literal by default, but
587        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
588        causes the error). The code is unchanged, but I tidied the documentation.
590    4.  Inside a character class, PCRE always treated \R and \X as literals,
591        whereas Perl faults them if its -w option is set. I have changed PCRE so
592        that it faults them when PCRE_EXTRA is set.
594    5.  Added support for \N, which always matches any character other than
595        newline. (It is the same as "." when PCRE_DOTALL is not set.)
597    6.  When compiling pcregrep with newer versions of gcc which may have
598        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
599        declared with attribute warn_unused_result" were given. Just casting the
600        result to (void) does not stop the warnings; a more elaborate fudge is
601        needed. I've used a macro to implement this.
603    7.  Minor change to pcretest.c to avoid a compiler warning.
605    8.  Added four artifical Unicode properties to help with an option to make
606        \s etc use properties (see next item). The new properties are: Xan
607        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
609    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
610        use Unicode properties. (*UCP) at the start of a pattern can be used to set
611        this option. Modified pcretest to add /W to test this facility. Added
612        REG_UCP to make it available via the POSIX interface.
614    10. Added --line-buffered to pcregrep.
616    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
617        studied, and the match started with a letter with a code point greater than
618        127 whose first byte was different to the first byte of the other case of
619        the letter, the other case of this starting letter was not recognized
620        (#976).
622    12. If a pattern that was studied started with a repeated Unicode property
623        test, for example, \p{Nd}+, there was the theoretical possibility of
624        setting up an incorrect bitmap of starting bytes, but fortunately it could
625        not have actually happened in practice until change 8 above was made (it
626        added property types that matched character-matching opcodes).
628    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
629        possible starting bytes for non-anchored patterns.
631    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
632        \R, and also a number of cases that involve Unicode properties, both
633        explicit and implicit when PCRE_UCP is set.
635    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
636        input, it could crash or give wrong results if characters with values
637        greater than 0xc0 were present in the subject string. (Detail: it assumed
638        UTF-8 input when processing these items.)
640    16. Added a lot of (int) casts to avoid compiler warnings in systems where
641        size_t is 64-bit (#991).
643    17. Added a check for running out of memory when PCRE is compiled with
644        --disable-stack-for-recursion (#990).
646    18. If the last data line in a file for pcretest does not have a newline on
647        the end, a newline was missing in the output.
649    19. The default pcre_chartables.c file recognizes only ASCII characters (values
650        less than 128) in its various bitmaps. However, there is a facility for
651        generating tables according to the current locale when PCRE is compiled. It
652        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
653        characters, are recognized by isspace() and therefore were getting set in
654        these tables, and indeed these tables seem to approximate to ISO 8859. This
655        caused a problem in UTF-8 mode when pcre_study() was used to create a list
656        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
657        which of course cannot start UTF-8 characters. I have changed the code so
658        that only real ASCII characters (less than 128) and the correct starting
659        bytes for UTF-8 encodings are set for characters greater than 127 when in
660        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
661        altogether.)
663    20. Added the /T option to pcretest so as to be able to run tests with non-
664        standard character tables, thus making it possible to include the tests
665        used for 19 above in the standard set of tests.
667    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
668        reference to a subpattern the other side of a comment that contains an
669        opening parenthesis caused either an internal compiling error, or a
670        reference to the wrong subpattern.
673    Version 8.02 19-Mar-2010
674    ------------------------
676    1.  The Unicode data tables have been updated to Unicode 5.2.0.
678    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
679        configured.
681    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
682        original author of that file, following a query about its status.
684    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
685        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
687    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
688        quantifier applied to a forward-referencing subroutine call, could compile
689        incorrect code or give the error "internal error: previously-checked
690        referenced subpattern not found".
692    6.  Both MS Visual Studio and Symbian OS have problems with initializing
693        variables to point to external functions. For these systems, therefore,
694        pcre_malloc etc. are now initialized to local functions that call the
695        relevant global functions.
697    7.  There were two entries missing in the vectors called coptable and poptable
698        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
699        I've fixed the data, and added a kludgy way of testing at compile time that
700        the lengths are correct (equal to the number of opcodes).
702    8.  Following on from 7, I added a similar kludge to check the length of the
703        eint vector in pcreposix.c.
705    9.  Error texts for pcre_compile() are held as one long string to avoid too
706        much relocation at load time. To find a text, the string is searched,
707        counting zeros. There was no check for running off the end of the string,
708        which could happen if a new error number was added without updating the
709        string.
711    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
713    11. \K was not working if it appeared in an atomic group or in a group that
714        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
715        \K is "not well defined" if used in an assertion. PCRE now accepts it if
716        the assertion is positive, but not if it is negative.
718    12. Change 11 fortuitously reduced the size of the stack frame used in the
719        "match()" function of pcre_exec.c by one pointer. Forthcoming
720        implementation of support for (*MARK) will need an extra pointer on the
721        stack; I have reserved it now, so that the stack frame size does not
722        decrease.
724    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
725        item in branch that calls a recursion is a subroutine call - as in the
726        second branch in the above example - was incorrectly given the compile-
727        time error "recursive call could loop indefinitely" because pcre_compile()
728        was not correctly checking the subroutine for matching a non-empty string.
730    14. The checks for overrunning compiling workspace could trigger after an
731        overrun had occurred. This is a "should never occur" error, but it can be
732        triggered by pathological patterns such as hundreds of nested parentheses.
733        The checks now trigger 100 bytes before the end of the workspace.
735    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
738    Version 8.01 19-Jan-2010
739    ------------------------
741  1.  If a pattern contained a conditional subpattern with only one branch (in  1.  If a pattern contained a conditional subpattern with only one branch (in
742      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
743      computed the wrong minimum data length (which is of course zero for such      computed the wrong minimum data length (which is of course zero for such
744      subpatterns).      subpatterns). This could cause incorrect "no match" results.
746  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
747      the pattern is reset in the first branch, pcre_compile() failed with      the pattern is reset in the first branch, pcre_compile() failed with
# Line 61  Version 8.01 06-Jan-10 Line 795  Version 8.01 06-Jan-10
795      custom one, because of the following reported problem in Windows:      custom one, because of the following reported problem in Windows:
797        - libbz2 uses the Pascal calling convention (WINAPI) for the functions        - libbz2 uses the Pascal calling convention (WINAPI) for the functions
798          under Win32.            under Win32.
799        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
800          therefore missing the function definition.            therefore missing the function definition.
801        - The compiler thus generates a "C" signature for the test function.        - The compiler thus generates a "C" signature for the test function.
802        - The linker fails to find the "C" function.        - The linker fails to find the "C" function.
803        - PCRE fails to configure if asked to do so against libbz2.        - PCRE fails to configure if asked to do so against libbz2.
# Line 113  Version 8.01 06-Jan-10 Line 847  Version 8.01 06-Jan-10
847      equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for      equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
848      instance, but it only takes 2 args instead of 3!"      instance, but it only takes 2 args instead of 3!"
850    18. A subtle bug concerned with back references has been fixed by a change of
851        specification, with a corresponding code fix. A pattern such as
852        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
853        refers, was giving matches when it shouldn't. For example, xa=xaaa would
854        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
855        same bug. Such groups have to be quantified to be useful, or contained
856        inside another quantified group. (If there's no repetition, the reference
857        can never match.) The problem arises because, having left the group and
858        moved on to the rest of the pattern, a later failure that backtracks into
859        the group uses the captured value from the final iteration of the group
860        rather than the correct earlier one. I have fixed this in PCRE by forcing
861        any group that contains a reference to itself to be an atomic group; that
862        is, there cannot be any backtracking into it once it has completed. This is
863        similar to recursive and subroutine calls.
866  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
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