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

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