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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.01 11-Dec-09  Version 8.21
5  ----------------------  ------------
6    
7    1.  Updating the JIT compiler.
8    
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
11    
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.
15    
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.
19    
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
22    
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.
26    
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.
36    
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
39    
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.
44    
45    
46    Version 8.20 21-Oct-2011
47    ------------------------
48    
49    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
50        a POSIX class. After further experiments with Perl, which convinced me that
51        Perl has bugs and confusions, a closing square bracket is no longer allowed
52        in a POSIX name. This bug also affected patterns with classes that started
53        with full stops.
54    
55    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
56        captured substring, but while checking the failing first alternative,
57        substring 1 is temporarily captured. If the output vector supplied to
58        pcre_exec() was not big enough for this capture, the yield of the function
59        was still zero ("insufficient space for captured substrings"). This cannot
60        be totally fixed without adding another stack variable, which seems a lot
61        of expense for a edge case. However, I have improved the situation in cases
62        such as /(a)(b)x|abc/ matched against "abc", where the return code
63        indicates that fewer than the maximum number of slots in the ovector have
64        been set.
65    
66    3.  Related to (2) above: when there are more back references in a pattern than
67        slots in the output vector, pcre_exec() uses temporary memory during
68        matching, and copies in the captures as far as possible afterwards. It was
69        using the entire output vector, but this conflicts with the specification
70        that only 2/3 is used for passing back captured substrings. Now it uses
71        only the first 2/3, for compatibility. This is, of course, another edge
72        case.
73    
74    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
75        main code base, and can be used by building with --enable-jit. When this is
76        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
77        runtime --no-jit option is given.
78    
79    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
80        ovector, the return from the function was zero, implying that there were
81        other matches that did not fit. The correct "exactly full" value is now
82        returned.
83    
84    6.  If a subpattern that was called recursively or as a subroutine contained
85        (*PRUNE) or any other control that caused it to give a non-standard return,
86        invalid errors such as "Error -26 (nested recursion at the same subject
87        position)" or even infinite loops could occur.
88    
89    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
90        computing the minimum length on reaching *ACCEPT, and so ended up with the
91        wrong value of 1 rather than 0. Further investigation indicates that
92        computing a minimum subject length in the presence of *ACCEPT is difficult
93        (think back references, subroutine calls), and so I have changed the code
94        so that no minimum is registered for a pattern that contains *ACCEPT.
95    
96    8.  If (*THEN) was present in the first (true) branch of a conditional group,
97        it was not handled as intended. [But see 16 below.]
98    
99    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
100        Sheri Pierce.
101    
102    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
103        the first byte in a match must be "a".
104    
105    11. Change 17 for 8.13 increased the recursion depth for patterns like
106        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
107        pattern contains any instances of (*THEN). If it does not, the old
108        optimizations are restored. It would be nice to do this on a per-group
109        basis, but at the moment that is not feasible.
110    
111    12. In some environments, the output of pcretest -C is CRLF terminated. This
112        broke RunTest's code that checks for the link size. A single white space
113        character after the value is now allowed for.
114    
115    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
116        For "fr", it uses the Windows-specific input and output files.
117    
118    14. If (*THEN) appeared in a group that was called recursively or as a
119        subroutine, it did not work as intended. [But see next item.]
120    
121    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
122        pattern fragments (but not containing any | characters). If A and B are
123        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
124        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
125        D. In other words, Perl considers parentheses that do not contain any |
126        characters to be part of a surrounding alternative, whereas PCRE was
127        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
128        differently. PCRE now behaves in the same way as Perl, except in the case
129        of subroutine/recursion calls such as (?1) which have in any case always
130        been different (but PCRE had them first :-).
131    
132    16. Related to 15 above: Perl does not treat the | in a conditional group as
133        creating alternatives. Such a group is treated in the same way as an
134        ordinary group without any | characters when processing (*THEN). PCRE has
135        been changed to match Perl's behaviour.
136    
137    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
138        RunGrepTest script failed.
139    
140    18. Change 22 for version 13 caused atomic groups to use more stack. This is
141        inevitable for groups that contain captures, but it can lead to a lot of
142        stack use in large patterns. The old behaviour has been restored for atomic
143        groups that do not contain any capturing parentheses.
144    
145    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
146        suppress the check for a minimum subject length at run time. (If it was
147        given to pcre_exec() or pcre_dfa_exec() it did work.)
148    
149    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
150        fail to work when decoding hex characters in data strings in EBCDIC
151        environments.
152    
153    21. It appears that in at least one Mac OS environment, the isxdigit() function
154        is implemented as a macro that evaluates to its argument more than once,
155        contravening the C 90 Standard (I haven't checked a later standard). There
156        was an instance in pcretest which caused it to go wrong when processing
157        \x{...} escapes in subject strings. The has been rewritten to avoid using
158        things like p++ in the argument of isxdigit().
159    
160    
161    Version 8.13 16-Aug-2011
162    ------------------------
163    
164    1.  The Unicode data tables have been updated to Unicode 6.0.0.
165    
166    2.  Two minor typos in pcre_internal.h have been fixed.
167    
168    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
169        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
170        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
171    
172    4.  There were a number of related bugs in the code for matching backrefences
173        caselessly in UTF-8 mode when codes for the characters concerned were
174        different numbers of bytes. For example, U+023A and U+2C65 are an upper
175        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
176        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
177        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
178        2-byte code at the end of the subject (it thought there wasn't enough data
179        left).
180    
181    5.  Comprehensive information about what went wrong is now returned by
182        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
183        as the output vector has at least 2 elements. The offset of the start of
184        the failing character and a reason code are placed in the vector.
185    
186    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
187        now returned is for the first byte of the failing character, instead of the
188        last byte inspected. This is an incompatible change, but I hope it is small
189        enough not to be a problem. It makes the returned offset consistent with
190        pcre_exec() and pcre_dfa_exec().
191    
192    7.  pcretest now gives a text phrase as well as the error number when
193        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
194        failure, the offset and reason code are output.
195    
196    8.  When \R was used with a maximizing quantifier it failed to skip backwards
197        over a \r\n pair if the subsequent match failed. Instead, it just skipped
198        back over a single character (\n). This seems wrong (because it treated the
199        two characters as a single entity when going forwards), conflicts with the
200        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
201        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
202        has been changed.
203    
204    9.  Some internal refactoring has changed the processing so that the handling
205        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
206        time (the PCRE_DOTALL option was changed this way some time ago: version
207        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
208        which was always a bit of a fudge. It also means that there is one less
209        argument for the match() function, which reduces its stack requirements
210        slightly. This change also fixes an incompatibility with Perl: the pattern
211        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
212    
213    10. More internal refactoring has drastically reduced the number of recursive
214        calls to match() for possessively repeated groups such as (abc)++ when
215        using pcre_exec().
216    
217    11. While implementing 10, a number of bugs in the handling of groups were
218        discovered and fixed:
219    
220        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
221        (a|)*(?1) gave a compile-time internal error.
222        ((a|)+)+  did not notice that the outer group could match an empty string.
223        (^a|^)+   was not marked as anchored.
224        (.*a|.*)+ was not marked as matching at start or after a newline.
225    
226    12. Yet more internal refactoring has removed another argument from the match()
227        function. Special calls to this function are now indicated by setting a
228        value in a variable in the "match data" data block.
229    
230    13. Be more explicit in pcre_study() instead of relying on "default" for
231        opcodes that mean there is no starting character; this means that when new
232        ones are added and accidentally left out of pcre_study(), testing should
233        pick them up.
234    
235    14. The -s option of pcretest has been documented for ages as being an old
236        synonym of -m (show memory usage). I have changed it to mean "force study
237        for every regex", that is, assume /S for every regex. This is similar to -i
238        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
239        using it. It makes it easier to run collections of tests with and without
240        study enabled, and thereby test pcre_study() more easily. All the standard
241        tests are now run with and without -s (but some patterns can be marked as
242        "never study" - see 20 below).
243    
244    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
245        restoration of the capturing data to the outer values was not happening
246        correctly.
247    
248    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
249        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
250        pattern had matched an empty string, and so incorrectly returned a no
251        match.
252    
253    17. There was optimizing code for the last branch of non-capturing parentheses,
254        and also for the obeyed branch of a conditional subexpression, which used
255        tail recursion to cut down on stack usage. Unfortunately, now that there is
256        the possibility of (*THEN) occurring in these branches, tail recursion is
257        no longer possible because the return has to be checked for (*THEN). These
258        two optimizations have therefore been removed. [But see 8.20/11 above.]
259    
260    18. If a pattern containing \R was studied, it was assumed that \R always
261        matched two bytes, thus causing the minimum subject length to be
262        incorrectly computed because \R can also match just one byte.
263    
264    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
265        was incorrectly computed.
266    
267    20. If /S is present twice on a test pattern in pcretest input, it now
268        *disables* studying, thereby overriding the use of -s on the command line
269        (see 14 above). This is necessary for one or two tests to keep the output
270        identical in both cases.
271    
272    21. When (*ACCEPT) was used in an assertion that matched an empty string and
273        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
274    
275    22. When an atomic group that contained a capturing parenthesis was
276        successfully matched, but the branch in which it appeared failed, the
277        capturing was not being forgotten if a higher numbered group was later
278        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
279        group 1 to "a", when in fact it should be unset. This applied to multi-
280        branched capturing and non-capturing groups, repeated or not, and also to
281        positive assertions (capturing in negative assertions does not happen
282        in PCRE) and also to nested atomic groups.
283    
284    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
285        subject after a captured substring, to make it easier to tell which of a
286        number of identical substrings has been captured.
287    
288    24. The way atomic groups are processed by pcre_exec() has been changed so that
289        if they are repeated, backtracking one repetition now resets captured
290        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
291        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
292        "aaa". Previously, it would have been "a". As part of this code
293        refactoring, the way recursive calls are handled has also been changed.
294    
295    25. If an assertion condition captured any substrings, they were not passed
296        back unless some other capturing happened later. For example, if
297        (?(?=(a))a) was matched against "a", no capturing was returned.
298    
299    26. When studying a pattern that contained subroutine calls or assertions,
300        the code for finding the minimum length of a possible match was handling
301        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
302        group 1 called group 2 while simultaneously a separate group 2 called group
303        1). A stack overflow occurred in this case. I have fixed this by limiting
304        the recursion depth to 10.
305    
306    27. Updated RunTest.bat in the distribution to the version supplied by Tom
307        Fortmann. This supports explicit test numbers on the command line, and has
308        argument validation and error reporting.
309    
310    28. An instance of \X with an unlimited repeat could fail if at any point the
311        first character it looked at was a mark character.
312    
313    29. Some minor code refactoring concerning Unicode properties and scripts
314        should reduce the stack requirement of match() slightly.
315    
316    30. Added the '=' option to pcretest to check the setting of unused capturing
317        slots at the end of the pattern, which are documented as being -1, but are
318        not included in the return count.
319    
320    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
321        compiled something random. Now it gives a compile-time error (as does
322        Perl).
323    
324    32. A *MARK encountered during the processing of a positive assertion is now
325        recorded and passed back (compatible with Perl).
326    
327    33. If --only-matching or --colour was set on a pcregrep call whose pattern
328        had alternative anchored branches, the search for a second match in a line
329        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
330        matched the line "0102" twice. The same bug affected patterns that started
331        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
332        twice.
333    
334    34. Previously, PCRE did not allow quantification of assertions. However, Perl
335        does, and because of capturing effects, quantifying parenthesized
336        assertions may at times be useful. Quantifiers are now allowed for
337        parenthesized assertions.
338    
339    35. A minor code tidy in pcre_compile() when checking options for \R usage.
340    
341    36. \g was being checked for fancy things in a character class, when it should
342        just be a literal "g".
343    
344    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
345        appearance of a nested POSIX class supersedes an apparent external class.
346        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
347        unescaped square brackets may also appear as part of class names. For
348        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
349        more like Perl. (But see 8.20/1 above.)
350    
351    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
352        was because it thought it was \N{name}, which is not supported).
353    
354    39. Add minix to OS list not supporting the -S option in pcretest.
355    
356    40. PCRE tries to detect cases of infinite recursion at compile time, but it
357        cannot analyze patterns in sufficient detail to catch mutual recursions
358        such as ((?1))((?2)). There is now a runtime test that gives an error if a
359        subgroup is called recursively as a subpattern for a second time at the
360        same position in the subject string. In previous releases this might have
361        been caught by the recursion limit, or it might have run out of stack.
362    
363    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
364        happen only once. PCRE was, however incorrectly giving a compile time error
365        "recursive call could loop indefinitely" because it cannot analyze the
366        pattern in sufficient detail. The compile time test no longer happens when
367        PCRE is compiling a conditional subpattern, but actual runaway loops are
368        now caught at runtime (see 40 above).
369    
370    42. It seems that Perl allows any characters other than a closing parenthesis
371        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
372        has been changed to be the same.
373    
374    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
375        as not to get warnings when autogen.sh is called. Also changed
376        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
377    
378    44. To help people who use pcregrep to scan files containing exceedingly long
379        lines, the following changes have been made:
380    
381        (a) The default value of the buffer size parameter has been increased from
382            8K to 20K. (The actual buffer used is three times this size.)
383    
384        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
385            PCRE is built.
386    
387        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
388            to be set at run time.
389    
390        (d) Numerical values in pcregrep options can be followed by K or M, for
391            example --buffer-size=50K.
392    
393        (e) If a line being scanned overflows pcregrep's buffer, an error is now
394            given and the return code is set to 2.
395    
396    45. Add a pointer to the latest mark to the callout data block.
397    
398    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
399        partial match of an empty string instead of no match. This was specific to
400        the use of ".".
401    
402    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
403        complete match instead of a partial match. This bug was dependent on both
404        the PCRE_UTF8 and PCRE_DOTALL options being set.
405    
406    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
407        starting byte set, because \b was not being ignored.
408    
409    
410    Version 8.12 15-Jan-2011
411    ------------------------
412    
413    1.  Fixed some typos in the markup of the man pages, and wrote a script that
414        checks for such things as part of the documentation building process.
415    
416    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
417        --match-limit and --recursion-limit options (added for 8.11). In
418        particular, this made one of the standard tests fail. (The integer value
419        went into the wrong half of a long int.)
420    
421    3.  If the --colour option was given to pcregrep with -v (invert match), it
422        did strange things, either producing crazy output, or crashing. It should,
423        of course, ignore a request for colour when reporting lines that do not
424        match.
425    
426    4.  Another pcregrep bug caused similar problems if --colour was specified with
427        -M (multiline) and the pattern match finished with a line ending.
428    
429    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
430        matched in multiline mode, the following line was shown as part of the
431        match. This seems wrong, so I have changed it.
432    
433    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
434        the check for further matches in the same line (so they could be coloured)
435        to overrun the end of the current line. If another match was found, it was
436        incorrectly shown (and then shown again when found in the next line).
437    
438    7.  If pcregrep was compiled under Windows, there was a reference to the
439        function pcregrep_exit() before it was defined. I am assuming this was
440        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
441        reported by a user. I've moved the definition above the reference.
442    
443    
444    Version 8.11 10-Dec-2010
445    ------------------------
446    
447    1.  (*THEN) was not working properly if there were untried alternatives prior
448        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
449        backtracked to try for "b" instead of moving to the next alternative branch
450        at the same level (in this case, to look for "c"). The Perl documentation
451        is clear that when (*THEN) is backtracked onto, it goes to the "next
452        alternative in the innermost enclosing group".
453    
454    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
455        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
456        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
457        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
458        (*THEN).
459    
460    3.  If \s appeared in a character class, it removed the VT character from
461        the class, even if it had been included by some previous item, for example
462        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
463        of \s, but is part of the POSIX "space" class.)
464    
465    4.  A partial match never returns an empty string (because you can always
466        match an empty string at the end of the subject); however the checking for
467        an empty string was starting at the "start of match" point. This has been
468        changed to the "earliest inspected character" point, because the returned
469        data for a partial match starts at this character. This means that, for
470        example, /(?<=abc)def/ gives a partial match for the subject "abc"
471        (previously it gave "no match").
472    
473    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
474        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
475        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
476        has an implication that the given string is incomplete (because a partial
477        match is preferred over a full match). For this reason, these items now
478        give a partial match in this situation. [Aside: previously, the one case
479        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
480        match rather than a full match, which was wrong by the old rules, but is
481        now correct.]
482    
483    6.  There was a bug in the handling of #-introduced comments, recognized when
484        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
485        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
486        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
487        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
488        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
489        places in pcre_compile().
490    
491    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
492        comments when looking ahead for named forward references to subpatterns,
493        the only newline sequence it recognized was NL. It now handles newlines
494        according to the set newline convention.
495    
496    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
497        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
498        cater for a lack of strerror(). These oversights have been fixed.
499    
500    9.  Added --match-limit and --recursion-limit to pcregrep.
501    
502    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
503    
504    11. When the -o option was used, pcregrep was setting a return code of 1, even
505        when matches were found, and --line-buffered was not being honoured.
506    
507    12. Added an optional parentheses number to the -o and --only-matching options
508        of pcregrep.
509    
510    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
511        can match an empty string. The code to do it in pcretest and pcredemo
512        needed fixing:
513    
514        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
515            only one byte after an empty string match just before CRLF (this case
516            just got forgotten; "any" and "anycrlf" were OK).
517    
518        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
519            mode when an empty string match preceded an ASCII character followed by
520            a non-ASCII character. (The code for advancing by one character rather
521            than one byte was nonsense.)
522    
523        (c) The pcredemo.c sample program did not have any code at all to handle
524            the cases when CRLF is a valid newline sequence.
525    
526    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
527        as a starting offset was within the subject string. There is now a new
528        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
529        negative or greater than the length of the string. In order to test this,
530        pcretest is extended to allow the setting of negative starting offsets.
531    
532    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
533        starting offset points to the beginning of a UTF-8 character was
534        unnecessarily clumsy. I tidied it up.
535    
536    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
537        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
538    
539    17. Nobody had reported that the --include_dir option, which was added in
540        release 7.7 should have been called --include-dir (hyphen, not underscore)
541        for compatibility with GNU grep. I have changed it to --include-dir, but
542        left --include_dir as an undocumented synonym, and the same for
543        --exclude-dir, though that is not available in GNU grep, at least as of
544        release 2.5.4.
545    
546    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
547        characters from a string of bytes) have been redefined so as not to use
548        loops, in order to improve performance in some environments. At the same
549        time, I abstracted some of the common code into auxiliary macros to save
550        repetition (this should not affect the compiled code).
551    
552    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
553        compile-time error is now given if \c is not followed by an ASCII
554        character, that is, a byte less than 128. (In EBCDIC mode, the code is
555        different, and any byte value is allowed.)
556    
557    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
558        START_OPTIMIZE option, which is now allowed at compile time - but just
559        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
560        to pcregrep and other applications that have no direct access to PCRE
561        options. The new /Y option in pcretest sets this option when calling
562        pcre_compile().
563    
564    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
565        back references. Groups containing recursive back references were forced to
566        be atomic by that change, but in the case of named groups, the amount of
567        memory required was incorrectly computed, leading to "Failed: internal
568        error: code overflow". This has been fixed.
569    
570    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
571        pcretest.c, to avoid build problems in some Borland environments.
572    
573    
574    Version 8.10 25-Jun-2010
575    ------------------------
576    
577    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
578        THEN.
579    
580    2.  (*ACCEPT) was not working when inside an atomic group.
581    
582    3.  Inside a character class, \B is treated as a literal by default, but
583        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
584        causes the error). The code is unchanged, but I tidied the documentation.
585    
586    4.  Inside a character class, PCRE always treated \R and \X as literals,
587        whereas Perl faults them if its -w option is set. I have changed PCRE so
588        that it faults them when PCRE_EXTRA is set.
589    
590    5.  Added support for \N, which always matches any character other than
591        newline. (It is the same as "." when PCRE_DOTALL is not set.)
592    
593    6.  When compiling pcregrep with newer versions of gcc which may have
594        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
595        declared with attribute warn_unused_result" were given. Just casting the
596        result to (void) does not stop the warnings; a more elaborate fudge is
597        needed. I've used a macro to implement this.
598    
599    7.  Minor change to pcretest.c to avoid a compiler warning.
600    
601    8.  Added four artifical Unicode properties to help with an option to make
602        \s etc use properties (see next item). The new properties are: Xan
603        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
604    
605    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
606        use Unicode properties. (*UCP) at the start of a pattern can be used to set
607        this option. Modified pcretest to add /W to test this facility. Added
608        REG_UCP to make it available via the POSIX interface.
609    
610    10. Added --line-buffered to pcregrep.
611    
612    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
613        studied, and the match started with a letter with a code point greater than
614        127 whose first byte was different to the first byte of the other case of
615        the letter, the other case of this starting letter was not recognized
616        (#976).
617    
618    12. If a pattern that was studied started with a repeated Unicode property
619        test, for example, \p{Nd}+, there was the theoretical possibility of
620        setting up an incorrect bitmap of starting bytes, but fortunately it could
621        not have actually happened in practice until change 8 above was made (it
622        added property types that matched character-matching opcodes).
623    
624    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
625        possible starting bytes for non-anchored patterns.
626    
627    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
628        \R, and also a number of cases that involve Unicode properties, both
629        explicit and implicit when PCRE_UCP is set.
630    
631    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
632        input, it could crash or give wrong results if characters with values
633        greater than 0xc0 were present in the subject string. (Detail: it assumed
634        UTF-8 input when processing these items.)
635    
636    16. Added a lot of (int) casts to avoid compiler warnings in systems where
637        size_t is 64-bit (#991).
638    
639    17. Added a check for running out of memory when PCRE is compiled with
640        --disable-stack-for-recursion (#990).
641    
642    18. If the last data line in a file for pcretest does not have a newline on
643        the end, a newline was missing in the output.
644    
645    19. The default pcre_chartables.c file recognizes only ASCII characters (values
646        less than 128) in its various bitmaps. However, there is a facility for
647        generating tables according to the current locale when PCRE is compiled. It
648        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
649        characters, are recognized by isspace() and therefore were getting set in
650        these tables, and indeed these tables seem to approximate to ISO 8859. This
651        caused a problem in UTF-8 mode when pcre_study() was used to create a list
652        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
653        which of course cannot start UTF-8 characters. I have changed the code so
654        that only real ASCII characters (less than 128) and the correct starting
655        bytes for UTF-8 encodings are set for characters greater than 127 when in
656        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
657        altogether.)
658    
659    20. Added the /T option to pcretest so as to be able to run tests with non-
660        standard character tables, thus making it possible to include the tests
661        used for 19 above in the standard set of tests.
662    
663    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
664        reference to a subpattern the other side of a comment that contains an
665        opening parenthesis caused either an internal compiling error, or a
666        reference to the wrong subpattern.
667    
668    
669    Version 8.02 19-Mar-2010
670    ------------------------
671    
672    1.  The Unicode data tables have been updated to Unicode 5.2.0.
673    
674    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
675        configured.
676    
677    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
678        original author of that file, following a query about its status.
679    
680    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
681        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
682    
683    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
684        quantifier applied to a forward-referencing subroutine call, could compile
685        incorrect code or give the error "internal error: previously-checked
686        referenced subpattern not found".
687    
688    6.  Both MS Visual Studio and Symbian OS have problems with initializing
689        variables to point to external functions. For these systems, therefore,
690        pcre_malloc etc. are now initialized to local functions that call the
691        relevant global functions.
692    
693    7.  There were two entries missing in the vectors called coptable and poptable
694        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
695        I've fixed the data, and added a kludgy way of testing at compile time that
696        the lengths are correct (equal to the number of opcodes).
697    
698    8.  Following on from 7, I added a similar kludge to check the length of the
699        eint vector in pcreposix.c.
700    
701    9.  Error texts for pcre_compile() are held as one long string to avoid too
702        much relocation at load time. To find a text, the string is searched,
703        counting zeros. There was no check for running off the end of the string,
704        which could happen if a new error number was added without updating the
705        string.
706    
707    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
708    
709    11. \K was not working if it appeared in an atomic group or in a group that
710        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
711        \K is "not well defined" if used in an assertion. PCRE now accepts it if
712        the assertion is positive, but not if it is negative.
713    
714    12. Change 11 fortuitously reduced the size of the stack frame used in the
715        "match()" function of pcre_exec.c by one pointer. Forthcoming
716        implementation of support for (*MARK) will need an extra pointer on the
717        stack; I have reserved it now, so that the stack frame size does not
718        decrease.
719    
720    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
721        item in branch that calls a recursion is a subroutine call - as in the
722        second branch in the above example - was incorrectly given the compile-
723        time error "recursive call could loop indefinitely" because pcre_compile()
724        was not correctly checking the subroutine for matching a non-empty string.
725    
726    14. The checks for overrunning compiling workspace could trigger after an
727        overrun had occurred. This is a "should never occur" error, but it can be
728        triggered by pathological patterns such as hundreds of nested parentheses.
729        The checks now trigger 100 bytes before the end of the workspace.
730    
731    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
732    
733    
734    Version 8.01 19-Jan-2010
735    ------------------------
736    
737  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
738      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
739      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
740      subpatterns).      subpatterns). This could cause incorrect "no match" results.
741    
742  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
743      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 26  Version 8.01 11-Dec-09 Line 756  Version 8.01 11-Dec-09
756      assertion subpattern, including such a pattern used as a condition,      assertion subpattern, including such a pattern used as a condition,
757      unpredictable results occurred, instead of the error return      unpredictable results occurred, instead of the error return
758      PCRE_ERROR_DFA_UITEM.      PCRE_ERROR_DFA_UITEM.
759    
760  5.  The C++ GlobalReplace function was not working like Perl for the special  5.  The C++ GlobalReplace function was not working like Perl for the special
761      situation when an empty string is matched. It now does the fancy magic      situation when an empty string is matched. It now does the fancy magic
762      stuff that is necessary.      stuff that is necessary.
763    
764  6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been  6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
765      removed. (These were left over from very, very early versions of PCRE.)      removed. (These were left over from very, very early versions of PCRE.)
766    
767  7.  Some cosmetic changes to the code to make life easier when compiling it  7.  Some cosmetic changes to the code to make life easier when compiling it
768      as part of something else:      as part of something else:
769    
770      (a) Change DEBUG to PCRE_DEBUG.      (a) Change DEBUG to PCRE_DEBUG.
771    
772      (b) In pcre_compile(), rename the member of the "branch_chain" structure      (b) In pcre_compile(), rename the member of the "branch_chain" structure
773          called "current" as "current_branch", to prevent a collision with the          called "current" as "current_branch", to prevent a collision with the
774          Linux macro when compiled as a kernel module.          Linux macro when compiled as a kernel module.
775    
776      (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to      (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
777          prevent a collision with the Linux macro when compiled as a kernel          prevent a collision with the Linux macro when compiled as a kernel
778          module.          module.
779    
780  8.  In pcre_compile() there are some checks for integer overflows that used to  8.  In pcre_compile() there are some checks for integer overflows that used to
781      cast potentially large values to (double). This has been changed to that      cast potentially large values to (double). This has been changed to that
782      when building, a check for int64_t is made, and if it is found, it is used      when building, a check for int64_t is made, and if it is found, it is used
783      instead, thus avoiding the use of floating point arithmetic. (There is no      instead, thus avoiding the use of floating point arithmetic. (There is no
784      other use of FP in PCRE.) If int64_t is not found, the fallback is to      other use of FP in PCRE.) If int64_t is not found, the fallback is to
785      double.      double.
786    
787  9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express  9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
788      2005 (difference between two addresses compared to an unsigned value).      2005 (difference between two addresses compared to an unsigned value).
789    
790    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
791        custom one, because of the following reported problem in Windows:
792    
793          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
794              under Win32.
795          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
796              therefore missing the function definition.
797          - The compiler thus generates a "C" signature for the test function.
798          - The linker fails to find the "C" function.
799          - PCRE fails to configure if asked to do so against libbz2.
800    
801    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
802        messages were output:
803    
804          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
805          rerunning libtoolize, to keep the correct libtool macros in-tree.
806          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
807    
808        I have done both of these things.
809    
810    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
811        most of the time, it *can* run out if it is given a pattern that contains a
812        runaway infinite recursion. I updated the discussion in the pcrestack man
813        page.
814    
815    13. Now that we have gone to the x.xx style of version numbers, the minor
816        version may start with zero. Using 08 or 09 is a bad idea because users
817        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
818        interpreted as invalid octal numbers. I've updated the previous comment in
819        configure.ac, and also added a check that gives an error if 08 or 09 are
820        used.
821    
822    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
823        causing partial matching to fail when the end of the subject matched \W
824        in a UTF-8 pattern where \W was quantified with a minimum of 3.
825    
826    15. There were some discrepancies between the declarations in pcre_internal.h
827        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
828        their definitions. The declarations used "const uschar *" and the
829        definitions used USPTR. Even though USPTR is normally defined as "const
830        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
831        reported that: "This difference in casting confuses some C++ compilers, for
832        example, SunCC recognizes above declarations as different functions and
833        generates broken code for hbpcre." I have changed the declarations to use
834        USPTR.
835    
836    16. GNU libtool is named differently on some systems. The autogen.sh script now
837        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
838        (FreeBSD).
839    
840    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
841        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
842        comment: "Figure out how to create a longlong from a string: strtoll and
843        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
844        instance, but it only takes 2 args instead of 3!"
845    
846    18. A subtle bug concerned with back references has been fixed by a change of
847        specification, with a corresponding code fix. A pattern such as
848        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
849        refers, was giving matches when it shouldn't. For example, xa=xaaa would
850        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
851        same bug. Such groups have to be quantified to be useful, or contained
852        inside another quantified group. (If there's no repetition, the reference
853        can never match.) The problem arises because, having left the group and
854        moved on to the rest of the pattern, a later failure that backtracks into
855        the group uses the captured value from the final iteration of the group
856        rather than the correct earlier one. I have fixed this in PCRE by forcing
857        any group that contains a reference to itself to be an atomic group; that
858        is, there cannot be any backtracking into it once it has completed. This is
859        similar to recursive and subroutine calls.
860    
861    
862  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09

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