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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.10 03-Jun-2010  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". The
60        maximum number of forward references (including repeats) was limited by the
61        internal workspace, and dependent on the LINK_SIZE. The code has been
62        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
63        the default depends on LINK_SIZE. There is a new upper limit (for safety)
64        of around 200,000 forward references. While doing this, I also speeded up
65        the filling in of repeated forward references.
66    
67    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
68        incorrectly expecting the subject to contain another "a" after the start.
69    
70    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
71        in the match, the SKIP should be ignored. This was not happening; instead
72        the SKIP was being treated as NOMATCH. For patterns such as
73        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
74        tested.
75    
76    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
77        now much more compatible with Perl, in particular in cases where the result
78        is a non-match for a non-anchored pattern. For example, if
79        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
80        "m", where previously it did not return a name. A side effect of this
81        change is that for partial matches, the last encountered mark name is
82        returned, as for non matches. A number of tests that were previously not
83        Perl-compatible have been moved into the Perl-compatible test files. The
84        refactoring has had the pleasing side effect of removing one argument from
85        the match() function, thus reducing its stack requirements.
86    
87    19. If the /S+ option was used in pcretest to study a pattern using JIT,
88        subsequent uses of /S (without +) incorrectly behaved like /S+.
89    
90    21. Retrieve executable code size support for the JIT compiler and fixing
91        some warnings.
92    
93    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
94        not work when the shorter character appeared right at the end of the
95        subject string.
96    
97    
98    Version 8.20 21-Oct-2011
99    ------------------------
100    
101    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
102        a POSIX class. After further experiments with Perl, which convinced me that
103        Perl has bugs and confusions, a closing square bracket is no longer allowed
104        in a POSIX name. This bug also affected patterns with classes that started
105        with full stops.
106    
107    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
108        captured substring, but while checking the failing first alternative,
109        substring 1 is temporarily captured. If the output vector supplied to
110        pcre_exec() was not big enough for this capture, the yield of the function
111        was still zero ("insufficient space for captured substrings"). This cannot
112        be totally fixed without adding another stack variable, which seems a lot
113        of expense for a edge case. However, I have improved the situation in cases
114        such as /(a)(b)x|abc/ matched against "abc", where the return code
115        indicates that fewer than the maximum number of slots in the ovector have
116        been set.
117    
118    3.  Related to (2) above: when there are more back references in a pattern than
119        slots in the output vector, pcre_exec() uses temporary memory during
120        matching, and copies in the captures as far as possible afterwards. It was
121        using the entire output vector, but this conflicts with the specification
122        that only 2/3 is used for passing back captured substrings. Now it uses
123        only the first 2/3, for compatibility. This is, of course, another edge
124        case.
125    
126    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
127        main code base, and can be used by building with --enable-jit. When this is
128        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
129        runtime --no-jit option is given.
130    
131    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
132        ovector, the return from the function was zero, implying that there were
133        other matches that did not fit. The correct "exactly full" value is now
134        returned.
135    
136    6.  If a subpattern that was called recursively or as a subroutine contained
137        (*PRUNE) or any other control that caused it to give a non-standard return,
138        invalid errors such as "Error -26 (nested recursion at the same subject
139        position)" or even infinite loops could occur.
140    
141    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
142        computing the minimum length on reaching *ACCEPT, and so ended up with the
143        wrong value of 1 rather than 0. Further investigation indicates that
144        computing a minimum subject length in the presence of *ACCEPT is difficult
145        (think back references, subroutine calls), and so I have changed the code
146        so that no minimum is registered for a pattern that contains *ACCEPT.
147    
148    8.  If (*THEN) was present in the first (true) branch of a conditional group,
149        it was not handled as intended. [But see 16 below.]
150    
151    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
152        Sheri Pierce.
153    
154    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
155        the first byte in a match must be "a".
156    
157    11. Change 17 for 8.13 increased the recursion depth for patterns like
158        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
159        pattern contains any instances of (*THEN). If it does not, the old
160        optimizations are restored. It would be nice to do this on a per-group
161        basis, but at the moment that is not feasible.
162    
163    12. In some environments, the output of pcretest -C is CRLF terminated. This
164        broke RunTest's code that checks for the link size. A single white space
165        character after the value is now allowed for.
166    
167    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
168        For "fr", it uses the Windows-specific input and output files.
169    
170    14. If (*THEN) appeared in a group that was called recursively or as a
171        subroutine, it did not work as intended. [But see next item.]
172    
173    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
174        pattern fragments (but not containing any | characters). If A and B are
175        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
176        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
177        D. In other words, Perl considers parentheses that do not contain any |
178        characters to be part of a surrounding alternative, whereas PCRE was
179        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
180        differently. PCRE now behaves in the same way as Perl, except in the case
181        of subroutine/recursion calls such as (?1) which have in any case always
182        been different (but PCRE had them first :-).
183    
184    16. Related to 15 above: Perl does not treat the | in a conditional group as
185        creating alternatives. Such a group is treated in the same way as an
186        ordinary group without any | characters when processing (*THEN). PCRE has
187        been changed to match Perl's behaviour.
188    
189    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
190        RunGrepTest script failed.
191    
192    18. Change 22 for version 13 caused atomic groups to use more stack. This is
193        inevitable for groups that contain captures, but it can lead to a lot of
194        stack use in large patterns. The old behaviour has been restored for atomic
195        groups that do not contain any capturing parentheses.
196    
197    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
198        suppress the check for a minimum subject length at run time. (If it was
199        given to pcre_exec() or pcre_dfa_exec() it did work.)
200    
201    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
202        fail to work when decoding hex characters in data strings in EBCDIC
203        environments.
204    
205    21. It appears that in at least one Mac OS environment, the isxdigit() function
206        is implemented as a macro that evaluates to its argument more than once,
207        contravening the C 90 Standard (I haven't checked a later standard). There
208        was an instance in pcretest which caused it to go wrong when processing
209        \x{...} escapes in subject strings. The has been rewritten to avoid using
210        things like p++ in the argument of isxdigit().
211    
212    
213    Version 8.13 16-Aug-2011
214    ------------------------
215    
216    1.  The Unicode data tables have been updated to Unicode 6.0.0.
217    
218    2.  Two minor typos in pcre_internal.h have been fixed.
219    
220    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
221        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
222        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
223    
224    4.  There were a number of related bugs in the code for matching backrefences
225        caselessly in UTF-8 mode when codes for the characters concerned were
226        different numbers of bytes. For example, U+023A and U+2C65 are an upper
227        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
228        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
229        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
230        2-byte code at the end of the subject (it thought there wasn't enough data
231        left).
232    
233    5.  Comprehensive information about what went wrong is now returned by
234        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
235        as the output vector has at least 2 elements. The offset of the start of
236        the failing character and a reason code are placed in the vector.
237    
238    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
239        now returned is for the first byte of the failing character, instead of the
240        last byte inspected. This is an incompatible change, but I hope it is small
241        enough not to be a problem. It makes the returned offset consistent with
242        pcre_exec() and pcre_dfa_exec().
243    
244    7.  pcretest now gives a text phrase as well as the error number when
245        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
246        failure, the offset and reason code are output.
247    
248    8.  When \R was used with a maximizing quantifier it failed to skip backwards
249        over a \r\n pair if the subsequent match failed. Instead, it just skipped
250        back over a single character (\n). This seems wrong (because it treated the
251        two characters as a single entity when going forwards), conflicts with the
252        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
253        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
254        has been changed.
255    
256    9.  Some internal refactoring has changed the processing so that the handling
257        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
258        time (the PCRE_DOTALL option was changed this way some time ago: version
259        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
260        which was always a bit of a fudge. It also means that there is one less
261        argument for the match() function, which reduces its stack requirements
262        slightly. This change also fixes an incompatibility with Perl: the pattern
263        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
264    
265    10. More internal refactoring has drastically reduced the number of recursive
266        calls to match() for possessively repeated groups such as (abc)++ when
267        using pcre_exec().
268    
269    11. While implementing 10, a number of bugs in the handling of groups were
270        discovered and fixed:
271    
272        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
273        (a|)*(?1) gave a compile-time internal error.
274        ((a|)+)+  did not notice that the outer group could match an empty string.
275        (^a|^)+   was not marked as anchored.
276        (.*a|.*)+ was not marked as matching at start or after a newline.
277    
278    12. Yet more internal refactoring has removed another argument from the match()
279        function. Special calls to this function are now indicated by setting a
280        value in a variable in the "match data" data block.
281    
282    13. Be more explicit in pcre_study() instead of relying on "default" for
283        opcodes that mean there is no starting character; this means that when new
284        ones are added and accidentally left out of pcre_study(), testing should
285        pick them up.
286    
287    14. The -s option of pcretest has been documented for ages as being an old
288        synonym of -m (show memory usage). I have changed it to mean "force study
289        for every regex", that is, assume /S for every regex. This is similar to -i
290        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
291        using it. It makes it easier to run collections of tests with and without
292        study enabled, and thereby test pcre_study() more easily. All the standard
293        tests are now run with and without -s (but some patterns can be marked as
294        "never study" - see 20 below).
295    
296    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
297        restoration of the capturing data to the outer values was not happening
298        correctly.
299    
300    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
301        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
302        pattern had matched an empty string, and so incorrectly returned a no
303        match.
304    
305    17. There was optimizing code for the last branch of non-capturing parentheses,
306        and also for the obeyed branch of a conditional subexpression, which used
307        tail recursion to cut down on stack usage. Unfortunately, now that there is
308        the possibility of (*THEN) occurring in these branches, tail recursion is
309        no longer possible because the return has to be checked for (*THEN). These
310        two optimizations have therefore been removed. [But see 8.20/11 above.]
311    
312    18. If a pattern containing \R was studied, it was assumed that \R always
313        matched two bytes, thus causing the minimum subject length to be
314        incorrectly computed because \R can also match just one byte.
315    
316    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
317        was incorrectly computed.
318    
319    20. If /S is present twice on a test pattern in pcretest input, it now
320        *disables* studying, thereby overriding the use of -s on the command line
321        (see 14 above). This is necessary for one or two tests to keep the output
322        identical in both cases.
323    
324    21. When (*ACCEPT) was used in an assertion that matched an empty string and
325        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
326    
327    22. When an atomic group that contained a capturing parenthesis was
328        successfully matched, but the branch in which it appeared failed, the
329        capturing was not being forgotten if a higher numbered group was later
330        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
331        group 1 to "a", when in fact it should be unset. This applied to multi-
332        branched capturing and non-capturing groups, repeated or not, and also to
333        positive assertions (capturing in negative assertions does not happen
334        in PCRE) and also to nested atomic groups.
335    
336    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
337        subject after a captured substring, to make it easier to tell which of a
338        number of identical substrings has been captured.
339    
340    24. The way atomic groups are processed by pcre_exec() has been changed so that
341        if they are repeated, backtracking one repetition now resets captured
342        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
343        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
344        "aaa". Previously, it would have been "a". As part of this code
345        refactoring, the way recursive calls are handled has also been changed.
346    
347    25. If an assertion condition captured any substrings, they were not passed
348        back unless some other capturing happened later. For example, if
349        (?(?=(a))a) was matched against "a", no capturing was returned.
350    
351    26. When studying a pattern that contained subroutine calls or assertions,
352        the code for finding the minimum length of a possible match was handling
353        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
354        group 1 called group 2 while simultaneously a separate group 2 called group
355        1). A stack overflow occurred in this case. I have fixed this by limiting
356        the recursion depth to 10.
357    
358    27. Updated RunTest.bat in the distribution to the version supplied by Tom
359        Fortmann. This supports explicit test numbers on the command line, and has
360        argument validation and error reporting.
361    
362    28. An instance of \X with an unlimited repeat could fail if at any point the
363        first character it looked at was a mark character.
364    
365    29. Some minor code refactoring concerning Unicode properties and scripts
366        should reduce the stack requirement of match() slightly.
367    
368    30. Added the '=' option to pcretest to check the setting of unused capturing
369        slots at the end of the pattern, which are documented as being -1, but are
370        not included in the return count.
371    
372    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
373        compiled something random. Now it gives a compile-time error (as does
374        Perl).
375    
376    32. A *MARK encountered during the processing of a positive assertion is now
377        recorded and passed back (compatible with Perl).
378    
379    33. If --only-matching or --colour was set on a pcregrep call whose pattern
380        had alternative anchored branches, the search for a second match in a line
381        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
382        matched the line "0102" twice. The same bug affected patterns that started
383        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
384        twice.
385    
386    34. Previously, PCRE did not allow quantification of assertions. However, Perl
387        does, and because of capturing effects, quantifying parenthesized
388        assertions may at times be useful. Quantifiers are now allowed for
389        parenthesized assertions.
390    
391    35. A minor code tidy in pcre_compile() when checking options for \R usage.
392    
393    36. \g was being checked for fancy things in a character class, when it should
394        just be a literal "g".
395    
396    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
397        appearance of a nested POSIX class supersedes an apparent external class.
398        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
399        unescaped square brackets may also appear as part of class names. For
400        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
401        more like Perl. (But see 8.20/1 above.)
402    
403    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
404        was because it thought it was \N{name}, which is not supported).
405    
406    39. Add minix to OS list not supporting the -S option in pcretest.
407    
408    40. PCRE tries to detect cases of infinite recursion at compile time, but it
409        cannot analyze patterns in sufficient detail to catch mutual recursions
410        such as ((?1))((?2)). There is now a runtime test that gives an error if a
411        subgroup is called recursively as a subpattern for a second time at the
412        same position in the subject string. In previous releases this might have
413        been caught by the recursion limit, or it might have run out of stack.
414    
415    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
416        happen only once. PCRE was, however incorrectly giving a compile time error
417        "recursive call could loop indefinitely" because it cannot analyze the
418        pattern in sufficient detail. The compile time test no longer happens when
419        PCRE is compiling a conditional subpattern, but actual runaway loops are
420        now caught at runtime (see 40 above).
421    
422    42. It seems that Perl allows any characters other than a closing parenthesis
423        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
424        has been changed to be the same.
425    
426    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
427        as not to get warnings when autogen.sh is called. Also changed
428        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
429    
430    44. To help people who use pcregrep to scan files containing exceedingly long
431        lines, the following changes have been made:
432    
433        (a) The default value of the buffer size parameter has been increased from
434            8K to 20K. (The actual buffer used is three times this size.)
435    
436        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
437            PCRE is built.
438    
439        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
440            to be set at run time.
441    
442        (d) Numerical values in pcregrep options can be followed by K or M, for
443            example --buffer-size=50K.
444    
445        (e) If a line being scanned overflows pcregrep's buffer, an error is now
446            given and the return code is set to 2.
447    
448    45. Add a pointer to the latest mark to the callout data block.
449    
450    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
451        partial match of an empty string instead of no match. This was specific to
452        the use of ".".
453    
454    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
455        complete match instead of a partial match. This bug was dependent on both
456        the PCRE_UTF8 and PCRE_DOTALL options being set.
457    
458    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
459        starting byte set, because \b was not being ignored.
460    
461    
462    Version 8.12 15-Jan-2011
463    ------------------------
464    
465    1.  Fixed some typos in the markup of the man pages, and wrote a script that
466        checks for such things as part of the documentation building process.
467    
468    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
469        --match-limit and --recursion-limit options (added for 8.11). In
470        particular, this made one of the standard tests fail. (The integer value
471        went into the wrong half of a long int.)
472    
473    3.  If the --colour option was given to pcregrep with -v (invert match), it
474        did strange things, either producing crazy output, or crashing. It should,
475        of course, ignore a request for colour when reporting lines that do not
476        match.
477    
478    4.  Another pcregrep bug caused similar problems if --colour was specified with
479        -M (multiline) and the pattern match finished with a line ending.
480    
481    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
482        matched in multiline mode, the following line was shown as part of the
483        match. This seems wrong, so I have changed it.
484    
485    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
486        the check for further matches in the same line (so they could be coloured)
487        to overrun the end of the current line. If another match was found, it was
488        incorrectly shown (and then shown again when found in the next line).
489    
490    7.  If pcregrep was compiled under Windows, there was a reference to the
491        function pcregrep_exit() before it was defined. I am assuming this was
492        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
493        reported by a user. I've moved the definition above the reference.
494    
495    
496    Version 8.11 10-Dec-2010
497    ------------------------
498    
499    1.  (*THEN) was not working properly if there were untried alternatives prior
500        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
501        backtracked to try for "b" instead of moving to the next alternative branch
502        at the same level (in this case, to look for "c"). The Perl documentation
503        is clear that when (*THEN) is backtracked onto, it goes to the "next
504        alternative in the innermost enclosing group".
505    
506    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
507        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
508        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
509        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
510        (*THEN).
511    
512    3.  If \s appeared in a character class, it removed the VT character from
513        the class, even if it had been included by some previous item, for example
514        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
515        of \s, but is part of the POSIX "space" class.)
516    
517    4.  A partial match never returns an empty string (because you can always
518        match an empty string at the end of the subject); however the checking for
519        an empty string was starting at the "start of match" point. This has been
520        changed to the "earliest inspected character" point, because the returned
521        data for a partial match starts at this character. This means that, for
522        example, /(?<=abc)def/ gives a partial match for the subject "abc"
523        (previously it gave "no match").
524    
525    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
526        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
527        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
528        has an implication that the given string is incomplete (because a partial
529        match is preferred over a full match). For this reason, these items now
530        give a partial match in this situation. [Aside: previously, the one case
531        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
532        match rather than a full match, which was wrong by the old rules, but is
533        now correct.]
534    
535    6.  There was a bug in the handling of #-introduced comments, recognized when
536        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
537        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
538        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
539        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
540        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
541        places in pcre_compile().
542    
543    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
544        comments when looking ahead for named forward references to subpatterns,
545        the only newline sequence it recognized was NL. It now handles newlines
546        according to the set newline convention.
547    
548    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
549        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
550        cater for a lack of strerror(). These oversights have been fixed.
551    
552    9.  Added --match-limit and --recursion-limit to pcregrep.
553    
554    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
555    
556    11. When the -o option was used, pcregrep was setting a return code of 1, even
557        when matches were found, and --line-buffered was not being honoured.
558    
559    12. Added an optional parentheses number to the -o and --only-matching options
560        of pcregrep.
561    
562    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
563        can match an empty string. The code to do it in pcretest and pcredemo
564        needed fixing:
565    
566        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
567            only one byte after an empty string match just before CRLF (this case
568            just got forgotten; "any" and "anycrlf" were OK).
569    
570        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
571            mode when an empty string match preceded an ASCII character followed by
572            a non-ASCII character. (The code for advancing by one character rather
573            than one byte was nonsense.)
574    
575        (c) The pcredemo.c sample program did not have any code at all to handle
576            the cases when CRLF is a valid newline sequence.
577    
578    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
579        as a starting offset was within the subject string. There is now a new
580        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
581        negative or greater than the length of the string. In order to test this,
582        pcretest is extended to allow the setting of negative starting offsets.
583    
584    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
585        starting offset points to the beginning of a UTF-8 character was
586        unnecessarily clumsy. I tidied it up.
587    
588    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
589        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
590    
591    17. Nobody had reported that the --include_dir option, which was added in
592        release 7.7 should have been called --include-dir (hyphen, not underscore)
593        for compatibility with GNU grep. I have changed it to --include-dir, but
594        left --include_dir as an undocumented synonym, and the same for
595        --exclude-dir, though that is not available in GNU grep, at least as of
596        release 2.5.4.
597    
598    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
599        characters from a string of bytes) have been redefined so as not to use
600        loops, in order to improve performance in some environments. At the same
601        time, I abstracted some of the common code into auxiliary macros to save
602        repetition (this should not affect the compiled code).
603    
604    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
605        compile-time error is now given if \c is not followed by an ASCII
606        character, that is, a byte less than 128. (In EBCDIC mode, the code is
607        different, and any byte value is allowed.)
608    
609    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
610        START_OPTIMIZE option, which is now allowed at compile time - but just
611        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
612        to pcregrep and other applications that have no direct access to PCRE
613        options. The new /Y option in pcretest sets this option when calling
614        pcre_compile().
615    
616    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
617        back references. Groups containing recursive back references were forced to
618        be atomic by that change, but in the case of named groups, the amount of
619        memory required was incorrectly computed, leading to "Failed: internal
620        error: code overflow". This has been fixed.
621    
622    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
623        pcretest.c, to avoid build problems in some Borland environments.
624    
625    
626    Version 8.10 25-Jun-2010
627  ------------------------  ------------------------
628    
629  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 42  Version 8.10 03-Jun-2010 Line 664  Version 8.10 03-Jun-2010
664  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
665      studied, and the match started with a letter with a code point greater than      studied, and the match started with a letter with a code point greater than
666      127 whose first byte was different to the first byte of the other case of      127 whose first byte was different to the first byte of the other case of
667      the letter, the other case of this starting letter was not recognized.      the letter, the other case of this starting letter was not recognized
668        (#976).
669    
670  12. pcreposix.c included pcre.h before including pcre_internal.h. This caused a  12. If a pattern that was studied started with a repeated Unicode property
     conflict in the definition of PCRE_EXP_DECL. I have removed the include of  
     pcre.h as pcre_internal.h includes pcre.h itself. (This may be a bit of  
     historical tidying that never got done.)  
   
 13. If a pattern that was studied started with a repeated Unicode property  
671      test, for example, \p{Nd}+, there was the theoretical possibility of      test, for example, \p{Nd}+, there was the theoretical possibility of
672      setting up an incorrect bitmap of starting bytes, but fortunately it could      setting up an incorrect bitmap of starting bytes, but fortunately it could
673      not have actually happened in practice until change 8 above was made (it      not have actually happened in practice until change 8 above was made (it
674      added property types that matched character-matching opcodes).      added property types that matched character-matching opcodes).
675    
676  14. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of  13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
677      possible starting bytes for non-anchored patterns.      possible starting bytes for non-anchored patterns.
678    
679  15. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes  14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
680      \R, and also a number of cases that involve Unicode properties, both      \R, and also a number of cases that involve Unicode properties, both
681      explicit and implicit when PCRE_UCP is set.      explicit and implicit when PCRE_UCP is set.
682    
683  16. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8  15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
684      input, it could crash or give wrong results if characters with values      input, it could crash or give wrong results if characters with values
685      greater than 0xc0 were present in the subject string. (Detail: it assumed      greater than 0xc0 were present in the subject string. (Detail: it assumed
686      UTF-8 input when processing these items.)      UTF-8 input when processing these items.)
687    
688  17. Added a lot of (int) casts to avoid compiler warnings in systems where  16. Added a lot of (int) casts to avoid compiler warnings in systems where
689      size_t is 64-bit.      size_t is 64-bit (#991).
690    
691    17. Added a check for running out of memory when PCRE is compiled with
692        --disable-stack-for-recursion (#990).
693    
694    18. If the last data line in a file for pcretest does not have a newline on
695        the end, a newline was missing in the output.
696    
697  18. Added a check for running out of memory when PCRE is compiled with  19. The default pcre_chartables.c file recognizes only ASCII characters (values
698      --disable-stack-for-recursion.      less than 128) in its various bitmaps. However, there is a facility for
699        generating tables according to the current locale when PCRE is compiled. It
700        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
701        characters, are recognized by isspace() and therefore were getting set in
702        these tables, and indeed these tables seem to approximate to ISO 8859. This
703        caused a problem in UTF-8 mode when pcre_study() was used to create a list
704        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
705        which of course cannot start UTF-8 characters. I have changed the code so
706        that only real ASCII characters (less than 128) and the correct starting
707        bytes for UTF-8 encodings are set for characters greater than 127 when in
708        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
709        altogether.)
710    
711    20. Added the /T option to pcretest so as to be able to run tests with non-
712        standard character tables, thus making it possible to include the tests
713        used for 19 above in the standard set of tests.
714    
715    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
716        reference to a subpattern the other side of a comment that contains an
717        opening parenthesis caused either an internal compiling error, or a
718        reference to the wrong subpattern.
719    
720    
721  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010

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