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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 05-Oct-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    10. Add a cast and remove a redundant test from the code.
46    
47    11. JIT should use pcre_malloc/pcre_free for allocation.
48    
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
52    
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
54    
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
57    
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". This
60        is now checked, and causes "too many forward references" instead.
61    
62    
63    Version 8.20 21-Oct-2011
64    ------------------------
65    
66    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
67        a POSIX class. After further experiments with Perl, which convinced me that
68        Perl has bugs and confusions, a closing square bracket is no longer allowed
69        in a POSIX name. This bug also affected patterns with classes that started
70        with full stops.
71    
72    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
73        captured substring, but while checking the failing first alternative,
74        substring 1 is temporarily captured. If the output vector supplied to
75        pcre_exec() was not big enough for this capture, the yield of the function
76        was still zero ("insufficient space for captured substrings"). This cannot
77        be totally fixed without adding another stack variable, which seems a lot
78        of expense for a edge case. However, I have improved the situation in cases
79        such as /(a)(b)x|abc/ matched against "abc", where the return code
80        indicates that fewer than the maximum number of slots in the ovector have
81        been set.
82    
83    3.  Related to (2) above: when there are more back references in a pattern than
84        slots in the output vector, pcre_exec() uses temporary memory during
85        matching, and copies in the captures as far as possible afterwards. It was
86        using the entire output vector, but this conflicts with the specification
87        that only 2/3 is used for passing back captured substrings. Now it uses
88        only the first 2/3, for compatibility. This is, of course, another edge
89        case.
90    
91    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
92        main code base, and can be used by building with --enable-jit. When this is
93        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
94        runtime --no-jit option is given.
95    
96    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
97        ovector, the return from the function was zero, implying that there were
98        other matches that did not fit. The correct "exactly full" value is now
99        returned.
100    
101    6.  If a subpattern that was called recursively or as a subroutine contained
102        (*PRUNE) or any other control that caused it to give a non-standard return,
103        invalid errors such as "Error -26 (nested recursion at the same subject
104        position)" or even infinite loops could occur.
105    
106    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
107        computing the minimum length on reaching *ACCEPT, and so ended up with the
108        wrong value of 1 rather than 0. Further investigation indicates that
109        computing a minimum subject length in the presence of *ACCEPT is difficult
110        (think back references, subroutine calls), and so I have changed the code
111        so that no minimum is registered for a pattern that contains *ACCEPT.
112    
113    8.  If (*THEN) was present in the first (true) branch of a conditional group,
114        it was not handled as intended. [But see 16 below.]
115    
116    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
117        Sheri Pierce.
118    
119    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
120        the first byte in a match must be "a".
121    
122    11. Change 17 for 8.13 increased the recursion depth for patterns like
123        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
124        pattern contains any instances of (*THEN). If it does not, the old
125        optimizations are restored. It would be nice to do this on a per-group
126        basis, but at the moment that is not feasible.
127    
128    12. In some environments, the output of pcretest -C is CRLF terminated. This
129        broke RunTest's code that checks for the link size. A single white space
130        character after the value is now allowed for.
131    
132    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
133        For "fr", it uses the Windows-specific input and output files.
134    
135    14. If (*THEN) appeared in a group that was called recursively or as a
136        subroutine, it did not work as intended. [But see next item.]
137    
138    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
139        pattern fragments (but not containing any | characters). If A and B are
140        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
141        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
142        D. In other words, Perl considers parentheses that do not contain any |
143        characters to be part of a surrounding alternative, whereas PCRE was
144        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
145        differently. PCRE now behaves in the same way as Perl, except in the case
146        of subroutine/recursion calls such as (?1) which have in any case always
147        been different (but PCRE had them first :-).
148    
149    16. Related to 15 above: Perl does not treat the | in a conditional group as
150        creating alternatives. Such a group is treated in the same way as an
151        ordinary group without any | characters when processing (*THEN). PCRE has
152        been changed to match Perl's behaviour.
153    
154    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
155        RunGrepTest script failed.
156    
157    18. Change 22 for version 13 caused atomic groups to use more stack. This is
158        inevitable for groups that contain captures, but it can lead to a lot of
159        stack use in large patterns. The old behaviour has been restored for atomic
160        groups that do not contain any capturing parentheses.
161    
162    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
163        suppress the check for a minimum subject length at run time. (If it was
164        given to pcre_exec() or pcre_dfa_exec() it did work.)
165    
166    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
167        fail to work when decoding hex characters in data strings in EBCDIC
168        environments.
169    
170    21. It appears that in at least one Mac OS environment, the isxdigit() function
171        is implemented as a macro that evaluates to its argument more than once,
172        contravening the C 90 Standard (I haven't checked a later standard). There
173        was an instance in pcretest which caused it to go wrong when processing
174        \x{...} escapes in subject strings. The has been rewritten to avoid using
175        things like p++ in the argument of isxdigit().
176    
177    
178    Version 8.13 16-Aug-2011
179    ------------------------
180    
181    1.  The Unicode data tables have been updated to Unicode 6.0.0.
182    
183    2.  Two minor typos in pcre_internal.h have been fixed.
184    
185    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
186        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
187        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
188    
189    4.  There were a number of related bugs in the code for matching backrefences
190        caselessly in UTF-8 mode when codes for the characters concerned were
191        different numbers of bytes. For example, U+023A and U+2C65 are an upper
192        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
193        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
194        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
195        2-byte code at the end of the subject (it thought there wasn't enough data
196        left).
197    
198    5.  Comprehensive information about what went wrong is now returned by
199        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
200        as the output vector has at least 2 elements. The offset of the start of
201        the failing character and a reason code are placed in the vector.
202    
203    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
204        now returned is for the first byte of the failing character, instead of the
205        last byte inspected. This is an incompatible change, but I hope it is small
206        enough not to be a problem. It makes the returned offset consistent with
207        pcre_exec() and pcre_dfa_exec().
208    
209    7.  pcretest now gives a text phrase as well as the error number when
210        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
211        failure, the offset and reason code are output.
212    
213    8.  When \R was used with a maximizing quantifier it failed to skip backwards
214        over a \r\n pair if the subsequent match failed. Instead, it just skipped
215        back over a single character (\n). This seems wrong (because it treated the
216        two characters as a single entity when going forwards), conflicts with the
217        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
218        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
219        has been changed.
220    
221    9.  Some internal refactoring has changed the processing so that the handling
222        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
223        time (the PCRE_DOTALL option was changed this way some time ago: version
224        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
225        which was always a bit of a fudge. It also means that there is one less
226        argument for the match() function, which reduces its stack requirements
227        slightly. This change also fixes an incompatibility with Perl: the pattern
228        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
229    
230    10. More internal refactoring has drastically reduced the number of recursive
231        calls to match() for possessively repeated groups such as (abc)++ when
232        using pcre_exec().
233    
234    11. While implementing 10, a number of bugs in the handling of groups were
235        discovered and fixed:
236    
237        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
238        (a|)*(?1) gave a compile-time internal error.
239        ((a|)+)+  did not notice that the outer group could match an empty string.
240        (^a|^)+   was not marked as anchored.
241        (.*a|.*)+ was not marked as matching at start or after a newline.
242    
243    12. Yet more internal refactoring has removed another argument from the match()
244        function. Special calls to this function are now indicated by setting a
245        value in a variable in the "match data" data block.
246    
247    13. Be more explicit in pcre_study() instead of relying on "default" for
248        opcodes that mean there is no starting character; this means that when new
249        ones are added and accidentally left out of pcre_study(), testing should
250        pick them up.
251    
252    14. The -s option of pcretest has been documented for ages as being an old
253        synonym of -m (show memory usage). I have changed it to mean "force study
254        for every regex", that is, assume /S for every regex. This is similar to -i
255        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
256        using it. It makes it easier to run collections of tests with and without
257        study enabled, and thereby test pcre_study() more easily. All the standard
258        tests are now run with and without -s (but some patterns can be marked as
259        "never study" - see 20 below).
260    
261    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
262        restoration of the capturing data to the outer values was not happening
263        correctly.
264    
265    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
266        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
267        pattern had matched an empty string, and so incorrectly returned a no
268        match.
269    
270    17. There was optimizing code for the last branch of non-capturing parentheses,
271        and also for the obeyed branch of a conditional subexpression, which used
272        tail recursion to cut down on stack usage. Unfortunately, now that there is
273        the possibility of (*THEN) occurring in these branches, tail recursion is
274        no longer possible because the return has to be checked for (*THEN). These
275        two optimizations have therefore been removed. [But see 8.20/11 above.]
276    
277    18. If a pattern containing \R was studied, it was assumed that \R always
278        matched two bytes, thus causing the minimum subject length to be
279        incorrectly computed because \R can also match just one byte.
280    
281    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
282        was incorrectly computed.
283    
284    20. If /S is present twice on a test pattern in pcretest input, it now
285        *disables* studying, thereby overriding the use of -s on the command line
286        (see 14 above). This is necessary for one or two tests to keep the output
287        identical in both cases.
288    
289    21. When (*ACCEPT) was used in an assertion that matched an empty string and
290        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
291    
292    22. When an atomic group that contained a capturing parenthesis was
293        successfully matched, but the branch in which it appeared failed, the
294        capturing was not being forgotten if a higher numbered group was later
295        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
296        group 1 to "a", when in fact it should be unset. This applied to multi-
297        branched capturing and non-capturing groups, repeated or not, and also to
298        positive assertions (capturing in negative assertions does not happen
299        in PCRE) and also to nested atomic groups.
300    
301    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
302        subject after a captured substring, to make it easier to tell which of a
303        number of identical substrings has been captured.
304    
305    24. The way atomic groups are processed by pcre_exec() has been changed so that
306        if they are repeated, backtracking one repetition now resets captured
307        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
308        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
309        "aaa". Previously, it would have been "a". As part of this code
310        refactoring, the way recursive calls are handled has also been changed.
311    
312    25. If an assertion condition captured any substrings, they were not passed
313        back unless some other capturing happened later. For example, if
314        (?(?=(a))a) was matched against "a", no capturing was returned.
315    
316    26. When studying a pattern that contained subroutine calls or assertions,
317        the code for finding the minimum length of a possible match was handling
318        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
319        group 1 called group 2 while simultaneously a separate group 2 called group
320        1). A stack overflow occurred in this case. I have fixed this by limiting
321        the recursion depth to 10.
322    
323    27. Updated RunTest.bat in the distribution to the version supplied by Tom
324        Fortmann. This supports explicit test numbers on the command line, and has
325        argument validation and error reporting.
326    
327    28. An instance of \X with an unlimited repeat could fail if at any point the
328        first character it looked at was a mark character.
329    
330    29. Some minor code refactoring concerning Unicode properties and scripts
331        should reduce the stack requirement of match() slightly.
332    
333    30. Added the '=' option to pcretest to check the setting of unused capturing
334        slots at the end of the pattern, which are documented as being -1, but are
335        not included in the return count.
336    
337    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
338        compiled something random. Now it gives a compile-time error (as does
339        Perl).
340    
341    32. A *MARK encountered during the processing of a positive assertion is now
342        recorded and passed back (compatible with Perl).
343    
344    33. If --only-matching or --colour was set on a pcregrep call whose pattern
345        had alternative anchored branches, the search for a second match in a line
346        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
347        matched the line "0102" twice. The same bug affected patterns that started
348        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
349        twice.
350    
351    34. Previously, PCRE did not allow quantification of assertions. However, Perl
352        does, and because of capturing effects, quantifying parenthesized
353        assertions may at times be useful. Quantifiers are now allowed for
354        parenthesized assertions.
355    
356    35. A minor code tidy in pcre_compile() when checking options for \R usage.
357    
358    36. \g was being checked for fancy things in a character class, when it should
359        just be a literal "g".
360    
361    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
362        appearance of a nested POSIX class supersedes an apparent external class.
363        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
364        unescaped square brackets may also appear as part of class names. For
365        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
366        more like Perl. (But see 8.20/1 above.)
367    
368    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
369        was because it thought it was \N{name}, which is not supported).
370    
371    39. Add minix to OS list not supporting the -S option in pcretest.
372    
373    40. PCRE tries to detect cases of infinite recursion at compile time, but it
374        cannot analyze patterns in sufficient detail to catch mutual recursions
375        such as ((?1))((?2)). There is now a runtime test that gives an error if a
376        subgroup is called recursively as a subpattern for a second time at the
377        same position in the subject string. In previous releases this might have
378        been caught by the recursion limit, or it might have run out of stack.
379    
380    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
381        happen only once. PCRE was, however incorrectly giving a compile time error
382        "recursive call could loop indefinitely" because it cannot analyze the
383        pattern in sufficient detail. The compile time test no longer happens when
384        PCRE is compiling a conditional subpattern, but actual runaway loops are
385        now caught at runtime (see 40 above).
386    
387    42. It seems that Perl allows any characters other than a closing parenthesis
388        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
389        has been changed to be the same.
390    
391    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
392        as not to get warnings when autogen.sh is called. Also changed
393        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
394    
395    44. To help people who use pcregrep to scan files containing exceedingly long
396        lines, the following changes have been made:
397    
398        (a) The default value of the buffer size parameter has been increased from
399            8K to 20K. (The actual buffer used is three times this size.)
400    
401        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
402            PCRE is built.
403    
404        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
405            to be set at run time.
406    
407        (d) Numerical values in pcregrep options can be followed by K or M, for
408            example --buffer-size=50K.
409    
410        (e) If a line being scanned overflows pcregrep's buffer, an error is now
411            given and the return code is set to 2.
412    
413    45. Add a pointer to the latest mark to the callout data block.
414    
415    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
416        partial match of an empty string instead of no match. This was specific to
417        the use of ".".
418    
419    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
420        complete match instead of a partial match. This bug was dependent on both
421        the PCRE_UTF8 and PCRE_DOTALL options being set.
422    
423    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
424        starting byte set, because \b was not being ignored.
425    
426    
427    Version 8.12 15-Jan-2011
428    ------------------------
429    
430    1.  Fixed some typos in the markup of the man pages, and wrote a script that
431        checks for such things as part of the documentation building process.
432    
433    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
434        --match-limit and --recursion-limit options (added for 8.11). In
435        particular, this made one of the standard tests fail. (The integer value
436        went into the wrong half of a long int.)
437    
438    3.  If the --colour option was given to pcregrep with -v (invert match), it
439        did strange things, either producing crazy output, or crashing. It should,
440        of course, ignore a request for colour when reporting lines that do not
441        match.
442    
443    4.  Another pcregrep bug caused similar problems if --colour was specified with
444        -M (multiline) and the pattern match finished with a line ending.
445    
446    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
447        matched in multiline mode, the following line was shown as part of the
448        match. This seems wrong, so I have changed it.
449    
450    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
451        the check for further matches in the same line (so they could be coloured)
452        to overrun the end of the current line. If another match was found, it was
453        incorrectly shown (and then shown again when found in the next line).
454    
455    7.  If pcregrep was compiled under Windows, there was a reference to the
456        function pcregrep_exit() before it was defined. I am assuming this was
457        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
458        reported by a user. I've moved the definition above the reference.
459    
460    
461    Version 8.11 10-Dec-2010
462    ------------------------
463    
464    1.  (*THEN) was not working properly if there were untried alternatives prior
465        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
466        backtracked to try for "b" instead of moving to the next alternative branch
467        at the same level (in this case, to look for "c"). The Perl documentation
468        is clear that when (*THEN) is backtracked onto, it goes to the "next
469        alternative in the innermost enclosing group".
470    
471    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
472        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
473        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
474        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
475        (*THEN).
476    
477    3.  If \s appeared in a character class, it removed the VT character from
478        the class, even if it had been included by some previous item, for example
479        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
480        of \s, but is part of the POSIX "space" class.)
481    
482    4.  A partial match never returns an empty string (because you can always
483        match an empty string at the end of the subject); however the checking for
484        an empty string was starting at the "start of match" point. This has been
485        changed to the "earliest inspected character" point, because the returned
486        data for a partial match starts at this character. This means that, for
487        example, /(?<=abc)def/ gives a partial match for the subject "abc"
488        (previously it gave "no match").
489    
490    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
491        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
492        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
493        has an implication that the given string is incomplete (because a partial
494        match is preferred over a full match). For this reason, these items now
495        give a partial match in this situation. [Aside: previously, the one case
496        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
497        match rather than a full match, which was wrong by the old rules, but is
498        now correct.]
499    
500    6.  There was a bug in the handling of #-introduced comments, recognized when
501        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
502        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
503        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
504        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
505        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
506        places in pcre_compile().
507    
508    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
509        comments when looking ahead for named forward references to subpatterns,
510        the only newline sequence it recognized was NL. It now handles newlines
511        according to the set newline convention.
512    
513    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
514        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
515        cater for a lack of strerror(). These oversights have been fixed.
516    
517    9.  Added --match-limit and --recursion-limit to pcregrep.
518    
519    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
520    
521    11. When the -o option was used, pcregrep was setting a return code of 1, even
522        when matches were found, and --line-buffered was not being honoured.
523    
524    12. Added an optional parentheses number to the -o and --only-matching options
525        of pcregrep.
526    
527    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
528        can match an empty string. The code to do it in pcretest and pcredemo
529        needed fixing:
530    
531        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
532            only one byte after an empty string match just before CRLF (this case
533            just got forgotten; "any" and "anycrlf" were OK).
534    
535        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
536            mode when an empty string match preceded an ASCII character followed by
537            a non-ASCII character. (The code for advancing by one character rather
538            than one byte was nonsense.)
539    
540        (c) The pcredemo.c sample program did not have any code at all to handle
541            the cases when CRLF is a valid newline sequence.
542    
543    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
544        as a starting offset was within the subject string. There is now a new
545        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
546        negative or greater than the length of the string. In order to test this,
547        pcretest is extended to allow the setting of negative starting offsets.
548    
549    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
550        starting offset points to the beginning of a UTF-8 character was
551        unnecessarily clumsy. I tidied it up.
552    
553    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
554        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
555    
556    17. Nobody had reported that the --include_dir option, which was added in
557        release 7.7 should have been called --include-dir (hyphen, not underscore)
558        for compatibility with GNU grep. I have changed it to --include-dir, but
559        left --include_dir as an undocumented synonym, and the same for
560        --exclude-dir, though that is not available in GNU grep, at least as of
561        release 2.5.4.
562    
563    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
564        characters from a string of bytes) have been redefined so as not to use
565        loops, in order to improve performance in some environments. At the same
566        time, I abstracted some of the common code into auxiliary macros to save
567        repetition (this should not affect the compiled code).
568    
569    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
570        compile-time error is now given if \c is not followed by an ASCII
571        character, that is, a byte less than 128. (In EBCDIC mode, the code is
572        different, and any byte value is allowed.)
573    
574    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
575        START_OPTIMIZE option, which is now allowed at compile time - but just
576        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
577        to pcregrep and other applications that have no direct access to PCRE
578        options. The new /Y option in pcretest sets this option when calling
579        pcre_compile().
580    
581    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
582        back references. Groups containing recursive back references were forced to
583        be atomic by that change, but in the case of named groups, the amount of
584        memory required was incorrectly computed, leading to "Failed: internal
585        error: code overflow". This has been fixed.
586    
587    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
588        pcretest.c, to avoid build problems in some Borland environments.
589    
590    
591    Version 8.10 25-Jun-2010
592    ------------------------
593    
594    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
595        THEN.
596    
597    2.  (*ACCEPT) was not working when inside an atomic group.
598    
599    3.  Inside a character class, \B is treated as a literal by default, but
600        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
601        causes the error). The code is unchanged, but I tidied the documentation.
602    
603    4.  Inside a character class, PCRE always treated \R and \X as literals,
604        whereas Perl faults them if its -w option is set. I have changed PCRE so
605        that it faults them when PCRE_EXTRA is set.
606    
607    5.  Added support for \N, which always matches any character other than
608        newline. (It is the same as "." when PCRE_DOTALL is not set.)
609    
610    6.  When compiling pcregrep with newer versions of gcc which may have
611        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
612        declared with attribute warn_unused_result" were given. Just casting the
613        result to (void) does not stop the warnings; a more elaborate fudge is
614        needed. I've used a macro to implement this.
615    
616    7.  Minor change to pcretest.c to avoid a compiler warning.
617    
618    8.  Added four artifical Unicode properties to help with an option to make
619        \s etc use properties (see next item). The new properties are: Xan
620        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
621    
622    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
623        use Unicode properties. (*UCP) at the start of a pattern can be used to set
624        this option. Modified pcretest to add /W to test this facility. Added
625        REG_UCP to make it available via the POSIX interface.
626    
627    10. Added --line-buffered to pcregrep.
628    
629    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
630        studied, and the match started with a letter with a code point greater than
631        127 whose first byte was different to the first byte of the other case of
632        the letter, the other case of this starting letter was not recognized
633        (#976).
634    
635    12. If a pattern that was studied started with a repeated Unicode property
636        test, for example, \p{Nd}+, there was the theoretical possibility of
637        setting up an incorrect bitmap of starting bytes, but fortunately it could
638        not have actually happened in practice until change 8 above was made (it
639        added property types that matched character-matching opcodes).
640    
641    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
642        possible starting bytes for non-anchored patterns.
643    
644    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
645        \R, and also a number of cases that involve Unicode properties, both
646        explicit and implicit when PCRE_UCP is set.
647    
648    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
649        input, it could crash or give wrong results if characters with values
650        greater than 0xc0 were present in the subject string. (Detail: it assumed
651        UTF-8 input when processing these items.)
652    
653    16. Added a lot of (int) casts to avoid compiler warnings in systems where
654        size_t is 64-bit (#991).
655    
656    17. Added a check for running out of memory when PCRE is compiled with
657        --disable-stack-for-recursion (#990).
658    
659    18. If the last data line in a file for pcretest does not have a newline on
660        the end, a newline was missing in the output.
661    
662    19. The default pcre_chartables.c file recognizes only ASCII characters (values
663        less than 128) in its various bitmaps. However, there is a facility for
664        generating tables according to the current locale when PCRE is compiled. It
665        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
666        characters, are recognized by isspace() and therefore were getting set in
667        these tables, and indeed these tables seem to approximate to ISO 8859. This
668        caused a problem in UTF-8 mode when pcre_study() was used to create a list
669        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
670        which of course cannot start UTF-8 characters. I have changed the code so
671        that only real ASCII characters (less than 128) and the correct starting
672        bytes for UTF-8 encodings are set for characters greater than 127 when in
673        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
674        altogether.)
675    
676    20. Added the /T option to pcretest so as to be able to run tests with non-
677        standard character tables, thus making it possible to include the tests
678        used for 19 above in the standard set of tests.
679    
680    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
681        reference to a subpattern the other side of a comment that contains an
682        opening parenthesis caused either an internal compiling error, or a
683        reference to the wrong subpattern.
684    
685    
686    Version 8.02 19-Mar-2010
687    ------------------------
688    
689    1.  The Unicode data tables have been updated to Unicode 5.2.0.
690    
691    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
692        configured.
693    
694    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
695        original author of that file, following a query about its status.
696    
697    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
698        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
699    
700    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
701        quantifier applied to a forward-referencing subroutine call, could compile
702        incorrect code or give the error "internal error: previously-checked
703        referenced subpattern not found".
704    
705    6.  Both MS Visual Studio and Symbian OS have problems with initializing
706        variables to point to external functions. For these systems, therefore,
707        pcre_malloc etc. are now initialized to local functions that call the
708        relevant global functions.
709    
710    7.  There were two entries missing in the vectors called coptable and poptable
711        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
712        I've fixed the data, and added a kludgy way of testing at compile time that
713        the lengths are correct (equal to the number of opcodes).
714    
715    8.  Following on from 7, I added a similar kludge to check the length of the
716        eint vector in pcreposix.c.
717    
718    9.  Error texts for pcre_compile() are held as one long string to avoid too
719        much relocation at load time. To find a text, the string is searched,
720        counting zeros. There was no check for running off the end of the string,
721        which could happen if a new error number was added without updating the
722        string.
723    
724    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
725    
726    11. \K was not working if it appeared in an atomic group or in a group that
727        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
728        \K is "not well defined" if used in an assertion. PCRE now accepts it if
729        the assertion is positive, but not if it is negative.
730    
731    12. Change 11 fortuitously reduced the size of the stack frame used in the
732        "match()" function of pcre_exec.c by one pointer. Forthcoming
733        implementation of support for (*MARK) will need an extra pointer on the
734        stack; I have reserved it now, so that the stack frame size does not
735        decrease.
736    
737    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
738        item in branch that calls a recursion is a subroutine call - as in the
739        second branch in the above example - was incorrectly given the compile-
740        time error "recursive call could loop indefinitely" because pcre_compile()
741        was not correctly checking the subroutine for matching a non-empty string.
742    
743    14. The checks for overrunning compiling workspace could trigger after an
744        overrun had occurred. This is a "should never occur" error, but it can be
745        triggered by pathological patterns such as hundreds of nested parentheses.
746        The checks now trigger 100 bytes before the end of the workspace.
747    
748    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
749    
750    
751    Version 8.01 19-Jan-2010
752    ------------------------
753    
754    1.  If a pattern contained a conditional subpattern with only one branch (in
755        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
756        computed the wrong minimum data length (which is of course zero for such
757        subpatterns). This could cause incorrect "no match" results.
758    
759    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
760        the pattern is reset in the first branch, pcre_compile() failed with
761        "internal error: code overflow at offset...". This happened only when
762        the reset was to the original external option setting. (An optimization
763        abstracts leading options settings into an external setting, which was the
764        cause of this.)
765    
766    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
767        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
768        assertion pattern did not match (meaning that the assertion was true), it
769        was incorrectly treated as false if the SKIP had been reached during the
770        matching. This also applied to assertions used as conditions.
771    
772    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
773        assertion subpattern, including such a pattern used as a condition,
774        unpredictable results occurred, instead of the error return
775        PCRE_ERROR_DFA_UITEM.
776    
777    5.  The C++ GlobalReplace function was not working like Perl for the special
778        situation when an empty string is matched. It now does the fancy magic
779        stuff that is necessary.
780    
781    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
782        removed. (These were left over from very, very early versions of PCRE.)
783    
784    7.  Some cosmetic changes to the code to make life easier when compiling it
785        as part of something else:
786    
787        (a) Change DEBUG to PCRE_DEBUG.
788    
789        (b) In pcre_compile(), rename the member of the "branch_chain" structure
790            called "current" as "current_branch", to prevent a collision with the
791            Linux macro when compiled as a kernel module.
792    
793        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
794            prevent a collision with the Linux macro when compiled as a kernel
795            module.
796    
797    8.  In pcre_compile() there are some checks for integer overflows that used to
798        cast potentially large values to (double). This has been changed to that
799        when building, a check for int64_t is made, and if it is found, it is used
800        instead, thus avoiding the use of floating point arithmetic. (There is no
801        other use of FP in PCRE.) If int64_t is not found, the fallback is to
802        double.
803    
804    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
805        2005 (difference between two addresses compared to an unsigned value).
806    
807    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
808        custom one, because of the following reported problem in Windows:
809    
810          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
811              under Win32.
812          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
813              therefore missing the function definition.
814          - The compiler thus generates a "C" signature for the test function.
815          - The linker fails to find the "C" function.
816          - PCRE fails to configure if asked to do so against libbz2.
817    
818    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
819        messages were output:
820    
821          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
822          rerunning libtoolize, to keep the correct libtool macros in-tree.
823          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
824    
825        I have done both of these things.
826    
827    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
828        most of the time, it *can* run out if it is given a pattern that contains a
829        runaway infinite recursion. I updated the discussion in the pcrestack man
830        page.
831    
832    13. Now that we have gone to the x.xx style of version numbers, the minor
833        version may start with zero. Using 08 or 09 is a bad idea because users
834        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
835        interpreted as invalid octal numbers. I've updated the previous comment in
836        configure.ac, and also added a check that gives an error if 08 or 09 are
837        used.
838    
839    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
840        causing partial matching to fail when the end of the subject matched \W
841        in a UTF-8 pattern where \W was quantified with a minimum of 3.
842    
843    15. There were some discrepancies between the declarations in pcre_internal.h
844        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
845        their definitions. The declarations used "const uschar *" and the
846        definitions used USPTR. Even though USPTR is normally defined as "const
847        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
848        reported that: "This difference in casting confuses some C++ compilers, for
849        example, SunCC recognizes above declarations as different functions and
850        generates broken code for hbpcre." I have changed the declarations to use
851        USPTR.
852    
853    16. GNU libtool is named differently on some systems. The autogen.sh script now
854        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
855        (FreeBSD).
856    
857    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
858        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
859        comment: "Figure out how to create a longlong from a string: strtoll and
860        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
861        instance, but it only takes 2 args instead of 3!"
862    
863    18. A subtle bug concerned with back references has been fixed by a change of
864        specification, with a corresponding code fix. A pattern such as
865        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
866        refers, was giving matches when it shouldn't. For example, xa=xaaa would
867        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
868        same bug. Such groups have to be quantified to be useful, or contained
869        inside another quantified group. (If there's no repetition, the reference
870        can never match.) The problem arises because, having left the group and
871        moved on to the rest of the pattern, a later failure that backtracks into
872        the group uses the captured value from the final iteration of the group
873        rather than the correct earlier one. I have fixed this in PCRE by forcing
874        any group that contains a reference to itself to be an atomic group; that
875        is, there cannot be any backtracking into it once it has completed. This is
876        similar to recursive and subroutine calls.
877    
878    
879    Version 8.00 19-Oct-09
880  ----------------------  ----------------------
881    
882  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
# Line 58  Version 8.00 05-Oct-09 Line 933  Version 8.00 05-Oct-09
933  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
934      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
935      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
936      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
     pcre_exec().  
937    
938  11. Partial matching with pcre_exec() is now more intuitive. A partial match  11. Partial matching with pcre_exec() is now more intuitive. A partial match
939      used to be given if ever the end of the subject was reached; now it is      used to be given if ever the end of the subject was reached; now it is

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