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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.6 21-Jan-08  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    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
98        systems.
99    
100    
101    Version 8.20 21-Oct-2011
102    ------------------------
103    
104    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
105        a POSIX class. After further experiments with Perl, which convinced me that
106        Perl has bugs and confusions, a closing square bracket is no longer allowed
107        in a POSIX name. This bug also affected patterns with classes that started
108        with full stops.
109    
110    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
111        captured substring, but while checking the failing first alternative,
112        substring 1 is temporarily captured. If the output vector supplied to
113        pcre_exec() was not big enough for this capture, the yield of the function
114        was still zero ("insufficient space for captured substrings"). This cannot
115        be totally fixed without adding another stack variable, which seems a lot
116        of expense for a edge case. However, I have improved the situation in cases
117        such as /(a)(b)x|abc/ matched against "abc", where the return code
118        indicates that fewer than the maximum number of slots in the ovector have
119        been set.
120    
121    3.  Related to (2) above: when there are more back references in a pattern than
122        slots in the output vector, pcre_exec() uses temporary memory during
123        matching, and copies in the captures as far as possible afterwards. It was
124        using the entire output vector, but this conflicts with the specification
125        that only 2/3 is used for passing back captured substrings. Now it uses
126        only the first 2/3, for compatibility. This is, of course, another edge
127        case.
128    
129    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
130        main code base, and can be used by building with --enable-jit. When this is
131        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
132        runtime --no-jit option is given.
133    
134    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
135        ovector, the return from the function was zero, implying that there were
136        other matches that did not fit. The correct "exactly full" value is now
137        returned.
138    
139    6.  If a subpattern that was called recursively or as a subroutine contained
140        (*PRUNE) or any other control that caused it to give a non-standard return,
141        invalid errors such as "Error -26 (nested recursion at the same subject
142        position)" or even infinite loops could occur.
143    
144    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
145        computing the minimum length on reaching *ACCEPT, and so ended up with the
146        wrong value of 1 rather than 0. Further investigation indicates that
147        computing a minimum subject length in the presence of *ACCEPT is difficult
148        (think back references, subroutine calls), and so I have changed the code
149        so that no minimum is registered for a pattern that contains *ACCEPT.
150    
151    8.  If (*THEN) was present in the first (true) branch of a conditional group,
152        it was not handled as intended. [But see 16 below.]
153    
154    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
155        Sheri Pierce.
156    
157    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
158        the first byte in a match must be "a".
159    
160    11. Change 17 for 8.13 increased the recursion depth for patterns like
161        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
162        pattern contains any instances of (*THEN). If it does not, the old
163        optimizations are restored. It would be nice to do this on a per-group
164        basis, but at the moment that is not feasible.
165    
166    12. In some environments, the output of pcretest -C is CRLF terminated. This
167        broke RunTest's code that checks for the link size. A single white space
168        character after the value is now allowed for.
169    
170    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
171        For "fr", it uses the Windows-specific input and output files.
172    
173    14. If (*THEN) appeared in a group that was called recursively or as a
174        subroutine, it did not work as intended. [But see next item.]
175    
176    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
177        pattern fragments (but not containing any | characters). If A and B are
178        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
179        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
180        D. In other words, Perl considers parentheses that do not contain any |
181        characters to be part of a surrounding alternative, whereas PCRE was
182        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
183        differently. PCRE now behaves in the same way as Perl, except in the case
184        of subroutine/recursion calls such as (?1) which have in any case always
185        been different (but PCRE had them first :-).
186    
187    16. Related to 15 above: Perl does not treat the | in a conditional group as
188        creating alternatives. Such a group is treated in the same way as an
189        ordinary group without any | characters when processing (*THEN). PCRE has
190        been changed to match Perl's behaviour.
191    
192    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
193        RunGrepTest script failed.
194    
195    18. Change 22 for version 13 caused atomic groups to use more stack. This is
196        inevitable for groups that contain captures, but it can lead to a lot of
197        stack use in large patterns. The old behaviour has been restored for atomic
198        groups that do not contain any capturing parentheses.
199    
200    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
201        suppress the check for a minimum subject length at run time. (If it was
202        given to pcre_exec() or pcre_dfa_exec() it did work.)
203    
204    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
205        fail to work when decoding hex characters in data strings in EBCDIC
206        environments.
207    
208    21. It appears that in at least one Mac OS environment, the isxdigit() function
209        is implemented as a macro that evaluates to its argument more than once,
210        contravening the C 90 Standard (I haven't checked a later standard). There
211        was an instance in pcretest which caused it to go wrong when processing
212        \x{...} escapes in subject strings. The has been rewritten to avoid using
213        things like p++ in the argument of isxdigit().
214    
215    
216    Version 8.13 16-Aug-2011
217    ------------------------
218    
219    1.  The Unicode data tables have been updated to Unicode 6.0.0.
220    
221    2.  Two minor typos in pcre_internal.h have been fixed.
222    
223    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
224        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
225        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
226    
227    4.  There were a number of related bugs in the code for matching backrefences
228        caselessly in UTF-8 mode when codes for the characters concerned were
229        different numbers of bytes. For example, U+023A and U+2C65 are an upper
230        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
231        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
232        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
233        2-byte code at the end of the subject (it thought there wasn't enough data
234        left).
235    
236    5.  Comprehensive information about what went wrong is now returned by
237        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
238        as the output vector has at least 2 elements. The offset of the start of
239        the failing character and a reason code are placed in the vector.
240    
241    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
242        now returned is for the first byte of the failing character, instead of the
243        last byte inspected. This is an incompatible change, but I hope it is small
244        enough not to be a problem. It makes the returned offset consistent with
245        pcre_exec() and pcre_dfa_exec().
246    
247    7.  pcretest now gives a text phrase as well as the error number when
248        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
249        failure, the offset and reason code are output.
250    
251    8.  When \R was used with a maximizing quantifier it failed to skip backwards
252        over a \r\n pair if the subsequent match failed. Instead, it just skipped
253        back over a single character (\n). This seems wrong (because it treated the
254        two characters as a single entity when going forwards), conflicts with the
255        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
256        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
257        has been changed.
258    
259    9.  Some internal refactoring has changed the processing so that the handling
260        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
261        time (the PCRE_DOTALL option was changed this way some time ago: version
262        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
263        which was always a bit of a fudge. It also means that there is one less
264        argument for the match() function, which reduces its stack requirements
265        slightly. This change also fixes an incompatibility with Perl: the pattern
266        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
267    
268    10. More internal refactoring has drastically reduced the number of recursive
269        calls to match() for possessively repeated groups such as (abc)++ when
270        using pcre_exec().
271    
272    11. While implementing 10, a number of bugs in the handling of groups were
273        discovered and fixed:
274    
275        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
276        (a|)*(?1) gave a compile-time internal error.
277        ((a|)+)+  did not notice that the outer group could match an empty string.
278        (^a|^)+   was not marked as anchored.
279        (.*a|.*)+ was not marked as matching at start or after a newline.
280    
281    12. Yet more internal refactoring has removed another argument from the match()
282        function. Special calls to this function are now indicated by setting a
283        value in a variable in the "match data" data block.
284    
285    13. Be more explicit in pcre_study() instead of relying on "default" for
286        opcodes that mean there is no starting character; this means that when new
287        ones are added and accidentally left out of pcre_study(), testing should
288        pick them up.
289    
290    14. The -s option of pcretest has been documented for ages as being an old
291        synonym of -m (show memory usage). I have changed it to mean "force study
292        for every regex", that is, assume /S for every regex. This is similar to -i
293        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
294        using it. It makes it easier to run collections of tests with and without
295        study enabled, and thereby test pcre_study() more easily. All the standard
296        tests are now run with and without -s (but some patterns can be marked as
297        "never study" - see 20 below).
298    
299    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
300        restoration of the capturing data to the outer values was not happening
301        correctly.
302    
303    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
304        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
305        pattern had matched an empty string, and so incorrectly returned a no
306        match.
307    
308    17. There was optimizing code for the last branch of non-capturing parentheses,
309        and also for the obeyed branch of a conditional subexpression, which used
310        tail recursion to cut down on stack usage. Unfortunately, now that there is
311        the possibility of (*THEN) occurring in these branches, tail recursion is
312        no longer possible because the return has to be checked for (*THEN). These
313        two optimizations have therefore been removed. [But see 8.20/11 above.]
314    
315    18. If a pattern containing \R was studied, it was assumed that \R always
316        matched two bytes, thus causing the minimum subject length to be
317        incorrectly computed because \R can also match just one byte.
318    
319    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
320        was incorrectly computed.
321    
322    20. If /S is present twice on a test pattern in pcretest input, it now
323        *disables* studying, thereby overriding the use of -s on the command line
324        (see 14 above). This is necessary for one or two tests to keep the output
325        identical in both cases.
326    
327    21. When (*ACCEPT) was used in an assertion that matched an empty string and
328        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
329    
330    22. When an atomic group that contained a capturing parenthesis was
331        successfully matched, but the branch in which it appeared failed, the
332        capturing was not being forgotten if a higher numbered group was later
333        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
334        group 1 to "a", when in fact it should be unset. This applied to multi-
335        branched capturing and non-capturing groups, repeated or not, and also to
336        positive assertions (capturing in negative assertions does not happen
337        in PCRE) and also to nested atomic groups.
338    
339    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
340        subject after a captured substring, to make it easier to tell which of a
341        number of identical substrings has been captured.
342    
343    24. The way atomic groups are processed by pcre_exec() has been changed so that
344        if they are repeated, backtracking one repetition now resets captured
345        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
346        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
347        "aaa". Previously, it would have been "a". As part of this code
348        refactoring, the way recursive calls are handled has also been changed.
349    
350    25. If an assertion condition captured any substrings, they were not passed
351        back unless some other capturing happened later. For example, if
352        (?(?=(a))a) was matched against "a", no capturing was returned.
353    
354    26. When studying a pattern that contained subroutine calls or assertions,
355        the code for finding the minimum length of a possible match was handling
356        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
357        group 1 called group 2 while simultaneously a separate group 2 called group
358        1). A stack overflow occurred in this case. I have fixed this by limiting
359        the recursion depth to 10.
360    
361    27. Updated RunTest.bat in the distribution to the version supplied by Tom
362        Fortmann. This supports explicit test numbers on the command line, and has
363        argument validation and error reporting.
364    
365    28. An instance of \X with an unlimited repeat could fail if at any point the
366        first character it looked at was a mark character.
367    
368    29. Some minor code refactoring concerning Unicode properties and scripts
369        should reduce the stack requirement of match() slightly.
370    
371    30. Added the '=' option to pcretest to check the setting of unused capturing
372        slots at the end of the pattern, which are documented as being -1, but are
373        not included in the return count.
374    
375    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
376        compiled something random. Now it gives a compile-time error (as does
377        Perl).
378    
379    32. A *MARK encountered during the processing of a positive assertion is now
380        recorded and passed back (compatible with Perl).
381    
382    33. If --only-matching or --colour was set on a pcregrep call whose pattern
383        had alternative anchored branches, the search for a second match in a line
384        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
385        matched the line "0102" twice. The same bug affected patterns that started
386        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
387        twice.
388    
389    34. Previously, PCRE did not allow quantification of assertions. However, Perl
390        does, and because of capturing effects, quantifying parenthesized
391        assertions may at times be useful. Quantifiers are now allowed for
392        parenthesized assertions.
393    
394    35. A minor code tidy in pcre_compile() when checking options for \R usage.
395    
396    36. \g was being checked for fancy things in a character class, when it should
397        just be a literal "g".
398    
399    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
400        appearance of a nested POSIX class supersedes an apparent external class.
401        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
402        unescaped square brackets may also appear as part of class names. For
403        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
404        more like Perl. (But see 8.20/1 above.)
405    
406    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
407        was because it thought it was \N{name}, which is not supported).
408    
409    39. Add minix to OS list not supporting the -S option in pcretest.
410    
411    40. PCRE tries to detect cases of infinite recursion at compile time, but it
412        cannot analyze patterns in sufficient detail to catch mutual recursions
413        such as ((?1))((?2)). There is now a runtime test that gives an error if a
414        subgroup is called recursively as a subpattern for a second time at the
415        same position in the subject string. In previous releases this might have
416        been caught by the recursion limit, or it might have run out of stack.
417    
418    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
419        happen only once. PCRE was, however incorrectly giving a compile time error
420        "recursive call could loop indefinitely" because it cannot analyze the
421        pattern in sufficient detail. The compile time test no longer happens when
422        PCRE is compiling a conditional subpattern, but actual runaway loops are
423        now caught at runtime (see 40 above).
424    
425    42. It seems that Perl allows any characters other than a closing parenthesis
426        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
427        has been changed to be the same.
428    
429    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
430        as not to get warnings when autogen.sh is called. Also changed
431        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
432    
433    44. To help people who use pcregrep to scan files containing exceedingly long
434        lines, the following changes have been made:
435    
436        (a) The default value of the buffer size parameter has been increased from
437            8K to 20K. (The actual buffer used is three times this size.)
438    
439        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
440            PCRE is built.
441    
442        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
443            to be set at run time.
444    
445        (d) Numerical values in pcregrep options can be followed by K or M, for
446            example --buffer-size=50K.
447    
448        (e) If a line being scanned overflows pcregrep's buffer, an error is now
449            given and the return code is set to 2.
450    
451    45. Add a pointer to the latest mark to the callout data block.
452    
453    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
454        partial match of an empty string instead of no match. This was specific to
455        the use of ".".
456    
457    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
458        complete match instead of a partial match. This bug was dependent on both
459        the PCRE_UTF8 and PCRE_DOTALL options being set.
460    
461    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
462        starting byte set, because \b was not being ignored.
463    
464    
465    Version 8.12 15-Jan-2011
466    ------------------------
467    
468    1.  Fixed some typos in the markup of the man pages, and wrote a script that
469        checks for such things as part of the documentation building process.
470    
471    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
472        --match-limit and --recursion-limit options (added for 8.11). In
473        particular, this made one of the standard tests fail. (The integer value
474        went into the wrong half of a long int.)
475    
476    3.  If the --colour option was given to pcregrep with -v (invert match), it
477        did strange things, either producing crazy output, or crashing. It should,
478        of course, ignore a request for colour when reporting lines that do not
479        match.
480    
481    4.  Another pcregrep bug caused similar problems if --colour was specified with
482        -M (multiline) and the pattern match finished with a line ending.
483    
484    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
485        matched in multiline mode, the following line was shown as part of the
486        match. This seems wrong, so I have changed it.
487    
488    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
489        the check for further matches in the same line (so they could be coloured)
490        to overrun the end of the current line. If another match was found, it was
491        incorrectly shown (and then shown again when found in the next line).
492    
493    7.  If pcregrep was compiled under Windows, there was a reference to the
494        function pcregrep_exit() before it was defined. I am assuming this was
495        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
496        reported by a user. I've moved the definition above the reference.
497    
498    
499    Version 8.11 10-Dec-2010
500    ------------------------
501    
502    1.  (*THEN) was not working properly if there were untried alternatives prior
503        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
504        backtracked to try for "b" instead of moving to the next alternative branch
505        at the same level (in this case, to look for "c"). The Perl documentation
506        is clear that when (*THEN) is backtracked onto, it goes to the "next
507        alternative in the innermost enclosing group".
508    
509    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
510        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
511        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
512        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
513        (*THEN).
514    
515    3.  If \s appeared in a character class, it removed the VT character from
516        the class, even if it had been included by some previous item, for example
517        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
518        of \s, but is part of the POSIX "space" class.)
519    
520    4.  A partial match never returns an empty string (because you can always
521        match an empty string at the end of the subject); however the checking for
522        an empty string was starting at the "start of match" point. This has been
523        changed to the "earliest inspected character" point, because the returned
524        data for a partial match starts at this character. This means that, for
525        example, /(?<=abc)def/ gives a partial match for the subject "abc"
526        (previously it gave "no match").
527    
528    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
529        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
530        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
531        has an implication that the given string is incomplete (because a partial
532        match is preferred over a full match). For this reason, these items now
533        give a partial match in this situation. [Aside: previously, the one case
534        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
535        match rather than a full match, which was wrong by the old rules, but is
536        now correct.]
537    
538    6.  There was a bug in the handling of #-introduced comments, recognized when
539        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
540        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
541        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
542        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
543        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
544        places in pcre_compile().
545    
546    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
547        comments when looking ahead for named forward references to subpatterns,
548        the only newline sequence it recognized was NL. It now handles newlines
549        according to the set newline convention.
550    
551    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
552        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
553        cater for a lack of strerror(). These oversights have been fixed.
554    
555    9.  Added --match-limit and --recursion-limit to pcregrep.
556    
557    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
558    
559    11. When the -o option was used, pcregrep was setting a return code of 1, even
560        when matches were found, and --line-buffered was not being honoured.
561    
562    12. Added an optional parentheses number to the -o and --only-matching options
563        of pcregrep.
564    
565    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
566        can match an empty string. The code to do it in pcretest and pcredemo
567        needed fixing:
568    
569        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
570            only one byte after an empty string match just before CRLF (this case
571            just got forgotten; "any" and "anycrlf" were OK).
572    
573        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
574            mode when an empty string match preceded an ASCII character followed by
575            a non-ASCII character. (The code for advancing by one character rather
576            than one byte was nonsense.)
577    
578        (c) The pcredemo.c sample program did not have any code at all to handle
579            the cases when CRLF is a valid newline sequence.
580    
581    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
582        as a starting offset was within the subject string. There is now a new
583        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
584        negative or greater than the length of the string. In order to test this,
585        pcretest is extended to allow the setting of negative starting offsets.
586    
587    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
588        starting offset points to the beginning of a UTF-8 character was
589        unnecessarily clumsy. I tidied it up.
590    
591    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
592        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
593    
594    17. Nobody had reported that the --include_dir option, which was added in
595        release 7.7 should have been called --include-dir (hyphen, not underscore)
596        for compatibility with GNU grep. I have changed it to --include-dir, but
597        left --include_dir as an undocumented synonym, and the same for
598        --exclude-dir, though that is not available in GNU grep, at least as of
599        release 2.5.4.
600    
601    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
602        characters from a string of bytes) have been redefined so as not to use
603        loops, in order to improve performance in some environments. At the same
604        time, I abstracted some of the common code into auxiliary macros to save
605        repetition (this should not affect the compiled code).
606    
607    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
608        compile-time error is now given if \c is not followed by an ASCII
609        character, that is, a byte less than 128. (In EBCDIC mode, the code is
610        different, and any byte value is allowed.)
611    
612    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
613        START_OPTIMIZE option, which is now allowed at compile time - but just
614        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
615        to pcregrep and other applications that have no direct access to PCRE
616        options. The new /Y option in pcretest sets this option when calling
617        pcre_compile().
618    
619    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
620        back references. Groups containing recursive back references were forced to
621        be atomic by that change, but in the case of named groups, the amount of
622        memory required was incorrectly computed, leading to "Failed: internal
623        error: code overflow". This has been fixed.
624    
625    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
626        pcretest.c, to avoid build problems in some Borland environments.
627    
628    
629    Version 8.10 25-Jun-2010
630    ------------------------
631    
632    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
633        THEN.
634    
635    2.  (*ACCEPT) was not working when inside an atomic group.
636    
637    3.  Inside a character class, \B is treated as a literal by default, but
638        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
639        causes the error). The code is unchanged, but I tidied the documentation.
640    
641    4.  Inside a character class, PCRE always treated \R and \X as literals,
642        whereas Perl faults them if its -w option is set. I have changed PCRE so
643        that it faults them when PCRE_EXTRA is set.
644    
645    5.  Added support for \N, which always matches any character other than
646        newline. (It is the same as "." when PCRE_DOTALL is not set.)
647    
648    6.  When compiling pcregrep with newer versions of gcc which may have
649        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
650        declared with attribute warn_unused_result" were given. Just casting the
651        result to (void) does not stop the warnings; a more elaborate fudge is
652        needed. I've used a macro to implement this.
653    
654    7.  Minor change to pcretest.c to avoid a compiler warning.
655    
656    8.  Added four artifical Unicode properties to help with an option to make
657        \s etc use properties (see next item). The new properties are: Xan
658        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
659    
660    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
661        use Unicode properties. (*UCP) at the start of a pattern can be used to set
662        this option. Modified pcretest to add /W to test this facility. Added
663        REG_UCP to make it available via the POSIX interface.
664    
665    10. Added --line-buffered to pcregrep.
666    
667    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
668        studied, and the match started with a letter with a code point greater than
669        127 whose first byte was different to the first byte of the other case of
670        the letter, the other case of this starting letter was not recognized
671        (#976).
672    
673    12. If a pattern that was studied started with a repeated Unicode property
674        test, for example, \p{Nd}+, there was the theoretical possibility of
675        setting up an incorrect bitmap of starting bytes, but fortunately it could
676        not have actually happened in practice until change 8 above was made (it
677        added property types that matched character-matching opcodes).
678    
679    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
680        possible starting bytes for non-anchored patterns.
681    
682    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
683        \R, and also a number of cases that involve Unicode properties, both
684        explicit and implicit when PCRE_UCP is set.
685    
686    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
687        input, it could crash or give wrong results if characters with values
688        greater than 0xc0 were present in the subject string. (Detail: it assumed
689        UTF-8 input when processing these items.)
690    
691    16. Added a lot of (int) casts to avoid compiler warnings in systems where
692        size_t is 64-bit (#991).
693    
694    17. Added a check for running out of memory when PCRE is compiled with
695        --disable-stack-for-recursion (#990).
696    
697    18. If the last data line in a file for pcretest does not have a newline on
698        the end, a newline was missing in the output.
699    
700    19. The default pcre_chartables.c file recognizes only ASCII characters (values
701        less than 128) in its various bitmaps. However, there is a facility for
702        generating tables according to the current locale when PCRE is compiled. It
703        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
704        characters, are recognized by isspace() and therefore were getting set in
705        these tables, and indeed these tables seem to approximate to ISO 8859. This
706        caused a problem in UTF-8 mode when pcre_study() was used to create a list
707        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
708        which of course cannot start UTF-8 characters. I have changed the code so
709        that only real ASCII characters (less than 128) and the correct starting
710        bytes for UTF-8 encodings are set for characters greater than 127 when in
711        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
712        altogether.)
713    
714    20. Added the /T option to pcretest so as to be able to run tests with non-
715        standard character tables, thus making it possible to include the tests
716        used for 19 above in the standard set of tests.
717    
718    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
719        reference to a subpattern the other side of a comment that contains an
720        opening parenthesis caused either an internal compiling error, or a
721        reference to the wrong subpattern.
722    
723    
724    Version 8.02 19-Mar-2010
725    ------------------------
726    
727    1.  The Unicode data tables have been updated to Unicode 5.2.0.
728    
729    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
730        configured.
731    
732    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
733        original author of that file, following a query about its status.
734    
735    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
736        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
737    
738    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
739        quantifier applied to a forward-referencing subroutine call, could compile
740        incorrect code or give the error "internal error: previously-checked
741        referenced subpattern not found".
742    
743    6.  Both MS Visual Studio and Symbian OS have problems with initializing
744        variables to point to external functions. For these systems, therefore,
745        pcre_malloc etc. are now initialized to local functions that call the
746        relevant global functions.
747    
748    7.  There were two entries missing in the vectors called coptable and poptable
749        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
750        I've fixed the data, and added a kludgy way of testing at compile time that
751        the lengths are correct (equal to the number of opcodes).
752    
753    8.  Following on from 7, I added a similar kludge to check the length of the
754        eint vector in pcreposix.c.
755    
756    9.  Error texts for pcre_compile() are held as one long string to avoid too
757        much relocation at load time. To find a text, the string is searched,
758        counting zeros. There was no check for running off the end of the string,
759        which could happen if a new error number was added without updating the
760        string.
761    
762    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
763    
764    11. \K was not working if it appeared in an atomic group or in a group that
765        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
766        \K is "not well defined" if used in an assertion. PCRE now accepts it if
767        the assertion is positive, but not if it is negative.
768    
769    12. Change 11 fortuitously reduced the size of the stack frame used in the
770        "match()" function of pcre_exec.c by one pointer. Forthcoming
771        implementation of support for (*MARK) will need an extra pointer on the
772        stack; I have reserved it now, so that the stack frame size does not
773        decrease.
774    
775    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
776        item in branch that calls a recursion is a subroutine call - as in the
777        second branch in the above example - was incorrectly given the compile-
778        time error "recursive call could loop indefinitely" because pcre_compile()
779        was not correctly checking the subroutine for matching a non-empty string.
780    
781    14. The checks for overrunning compiling workspace could trigger after an
782        overrun had occurred. This is a "should never occur" error, but it can be
783        triggered by pathological patterns such as hundreds of nested parentheses.
784        The checks now trigger 100 bytes before the end of the workspace.
785    
786    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
787    
788    
789    Version 8.01 19-Jan-2010
790    ------------------------
791    
792    1.  If a pattern contained a conditional subpattern with only one branch (in
793        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
794        computed the wrong minimum data length (which is of course zero for such
795        subpatterns). This could cause incorrect "no match" results.
796    
797    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
798        the pattern is reset in the first branch, pcre_compile() failed with
799        "internal error: code overflow at offset...". This happened only when
800        the reset was to the original external option setting. (An optimization
801        abstracts leading options settings into an external setting, which was the
802        cause of this.)
803    
804    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
805        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
806        assertion pattern did not match (meaning that the assertion was true), it
807        was incorrectly treated as false if the SKIP had been reached during the
808        matching. This also applied to assertions used as conditions.
809    
810    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
811        assertion subpattern, including such a pattern used as a condition,
812        unpredictable results occurred, instead of the error return
813        PCRE_ERROR_DFA_UITEM.
814    
815    5.  The C++ GlobalReplace function was not working like Perl for the special
816        situation when an empty string is matched. It now does the fancy magic
817        stuff that is necessary.
818    
819    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
820        removed. (These were left over from very, very early versions of PCRE.)
821    
822    7.  Some cosmetic changes to the code to make life easier when compiling it
823        as part of something else:
824    
825        (a) Change DEBUG to PCRE_DEBUG.
826    
827        (b) In pcre_compile(), rename the member of the "branch_chain" structure
828            called "current" as "current_branch", to prevent a collision with the
829            Linux macro when compiled as a kernel module.
830    
831        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
832            prevent a collision with the Linux macro when compiled as a kernel
833            module.
834    
835    8.  In pcre_compile() there are some checks for integer overflows that used to
836        cast potentially large values to (double). This has been changed to that
837        when building, a check for int64_t is made, and if it is found, it is used
838        instead, thus avoiding the use of floating point arithmetic. (There is no
839        other use of FP in PCRE.) If int64_t is not found, the fallback is to
840        double.
841    
842    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
843        2005 (difference between two addresses compared to an unsigned value).
844    
845    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
846        custom one, because of the following reported problem in Windows:
847    
848          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
849              under Win32.
850          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
851              therefore missing the function definition.
852          - The compiler thus generates a "C" signature for the test function.
853          - The linker fails to find the "C" function.
854          - PCRE fails to configure if asked to do so against libbz2.
855    
856    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
857        messages were output:
858    
859          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
860          rerunning libtoolize, to keep the correct libtool macros in-tree.
861          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
862    
863        I have done both of these things.
864    
865    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
866        most of the time, it *can* run out if it is given a pattern that contains a
867        runaway infinite recursion. I updated the discussion in the pcrestack man
868        page.
869    
870    13. Now that we have gone to the x.xx style of version numbers, the minor
871        version may start with zero. Using 08 or 09 is a bad idea because users
872        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
873        interpreted as invalid octal numbers. I've updated the previous comment in
874        configure.ac, and also added a check that gives an error if 08 or 09 are
875        used.
876    
877    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
878        causing partial matching to fail when the end of the subject matched \W
879        in a UTF-8 pattern where \W was quantified with a minimum of 3.
880    
881    15. There were some discrepancies between the declarations in pcre_internal.h
882        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
883        their definitions. The declarations used "const uschar *" and the
884        definitions used USPTR. Even though USPTR is normally defined as "const
885        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
886        reported that: "This difference in casting confuses some C++ compilers, for
887        example, SunCC recognizes above declarations as different functions and
888        generates broken code for hbpcre." I have changed the declarations to use
889        USPTR.
890    
891    16. GNU libtool is named differently on some systems. The autogen.sh script now
892        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
893        (FreeBSD).
894    
895    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
896        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
897        comment: "Figure out how to create a longlong from a string: strtoll and
898        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
899        instance, but it only takes 2 args instead of 3!"
900    
901    18. A subtle bug concerned with back references has been fixed by a change of
902        specification, with a corresponding code fix. A pattern such as
903        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
904        refers, was giving matches when it shouldn't. For example, xa=xaaa would
905        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
906        same bug. Such groups have to be quantified to be useful, or contained
907        inside another quantified group. (If there's no repetition, the reference
908        can never match.) The problem arises because, having left the group and
909        moved on to the rest of the pattern, a later failure that backtracks into
910        the group uses the captured value from the final iteration of the group
911        rather than the correct earlier one. I have fixed this in PCRE by forcing
912        any group that contains a reference to itself to be an atomic group; that
913        is, there cannot be any backtracking into it once it has completed. This is
914        similar to recursive and subroutine calls.
915    
916    
917    Version 8.00 19-Oct-09
918    ----------------------
919    
920    1.  The table for translating pcre_compile() error codes into POSIX error codes
921        was out-of-date, and there was no check on the pcre_compile() error code
922        being within the table. This could lead to an OK return being given in
923        error.
924    
925    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
926        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
927        in a Windows environment.
928    
929    3.  The pcregrep --count option prints the count for each file even when it is
930        zero, as does GNU grep. However, pcregrep was also printing all files when
931        --files-with-matches was added. Now, when both options are given, it prints
932        counts only for those files that have at least one match. (GNU grep just
933        prints the file name in this circumstance, but including the count seems
934        more useful - otherwise, why use --count?) Also ensured that the
935        combination -clh just lists non-zero counts, with no names.
936    
937    4.  The long form of the pcregrep -F option was incorrectly implemented as
938        --fixed_strings instead of --fixed-strings. This is an incompatible change,
939        but it seems right to fix it, and I didn't think it was worth preserving
940        the old behaviour.
941    
942    5.  The command line items --regex=pattern and --regexp=pattern were not
943        recognized by pcregrep, which required --regex pattern or --regexp pattern
944        (with a space rather than an '='). The man page documented the '=' forms,
945        which are compatible with GNU grep; these now work.
946    
947    6.  No libpcreposix.pc file was created for pkg-config; there was just
948        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
949    
950    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
951        when UCP support is not needed, by modifying the Python script that
952        generates it from Unicode data files. This should not matter if the module
953        is correctly used as a library, but I received one complaint about 50K of
954        unwanted data. My guess is that the person linked everything into his
955        program rather than using a library. Anyway, it does no harm.
956    
957    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
958        was a minimum greater than 1 for a wide character in a possessive
959        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
960        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
961        character. Chaos in the form of incorrect output or a compiling loop could
962        result.
963    
964    9.  The restrictions on what a pattern can contain when partial matching is
965        requested for pcre_exec() have been removed. All patterns can now be
966        partially matched by this function. In addition, if there are at least two
967        slots in the offset vector, the offset of the earliest inspected character
968        for the match and the offset of the end of the subject are set in them when
969        PCRE_ERROR_PARTIAL is returned.
970    
971    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
972        synonymous with PCRE_PARTIAL, for backwards compatibility, and
973        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
974        and may be more useful for multi-segment matching.
975    
976    11. Partial matching with pcre_exec() is now more intuitive. A partial match
977        used to be given if ever the end of the subject was reached; now it is
978        given only if matching could not proceed because another character was
979        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
980        string "Z", which now yields "no match" instead of "partial match". In the
981        case of pcre_dfa_exec(), "no match" is given if every matching path for the
982        final character ended with (*FAIL).
983    
984    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
985        if the pattern had a "must contain" character that was already found in the
986        earlier partial match, unless partial matching was again requested. For
987        example, with the pattern /dog.(body)?/, the "must contain" character is
988        "g". If the first part-match was for the string "dog", restarting with
989        "sbody" failed. This bug has been fixed.
990    
991    13. The string returned by pcre_dfa_exec() after a partial match has been
992        changed so that it starts at the first inspected character rather than the
993        first character of the match. This makes a difference only if the pattern
994        starts with a lookbehind assertion or \b or \B (\K is not supported by
995        pcre_dfa_exec()). It's an incompatible change, but it makes the two
996        matching functions compatible, and I think it's the right thing to do.
997    
998    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
999        so that the demonstration program is easily available in environments where
1000        PCRE has not been installed from source.
1001    
1002    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1003        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1004        library.
1005    
1006    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1007        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1008        is not the first non-POSIX option to be added. Clearly some people find
1009        these options useful.
1010    
1011    17. If a caller to the POSIX matching function regexec() passes a non-zero
1012        value for nmatch with a NULL value for pmatch, the value of
1013        nmatch is forced to zero.
1014    
1015    18. RunGrepTest did not have a test for the availability of the -u option of
1016        the diff command, as RunTest does. It now checks in the same way as
1017        RunTest, and also checks for the -b option.
1018    
1019    19. If an odd number of negated classes containing just a single character
1020        interposed, within parentheses, between a forward reference to a named
1021        subpattern and the definition of the subpattern, compilation crashed with
1022        an internal error, complaining that it could not find the referenced
1023        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1024        [The bug was that it was starting one character too far in when skipping
1025        over the character class, thus treating the ] as data rather than
1026        terminating the class. This meant it could skip too much.]
1027    
1028    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1029        /g option in pcretest when the pattern contains \K, which makes it possible
1030        to have an empty string match not at the start, even when the pattern is
1031        anchored. Updated pcretest and pcredemo to use this option.
1032    
1033    21. If the maximum number of capturing subpatterns in a recursion was greater
1034        than the maximum at the outer level, the higher number was returned, but
1035        with unset values at the outer level. The correct (outer level) value is
1036        now given.
1037    
1038    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1039        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1040        make it do so. The string so far is captured, making this feature
1041        compatible with Perl.
1042    
1043    23. The tests have been re-organized, adding tests 11 and 12, to make it
1044        possible to check the Perl 5.10 features against Perl 5.10.
1045    
1046    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1047        pattern matches a fixed length string. PCRE did not allow this; now it
1048        does. Neither allows recursion.
1049    
1050    25. I finally figured out how to implement a request to provide the minimum
1051        length of subject string that was needed in order to match a given pattern.
1052        (It was back references and recursion that I had previously got hung up
1053        on.) This code has now been added to pcre_study(); it finds a lower bound
1054        to the length of subject needed. It is not necessarily the greatest lower
1055        bound, but using it to avoid searching strings that are too short does give
1056        some useful speed-ups. The value is available to calling programs via
1057        pcre_fullinfo().
1058    
1059    26. While implementing 25, I discovered to my embarrassment that pcretest had
1060        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1061        study optimizations had never been tested with that matching function.
1062        Oops. What is worse, even when it was passed study data, there was a bug in
1063        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1064        were also very few tests of studied patterns with pcre_dfa_exec().
1065    
1066    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1067        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1068        on the other side of the coin, they are no longer allowed to have different
1069        names, because these cannot be distinguished in PCRE, and this has caused
1070        confusion. (This is a difference from Perl.)
1071    
1072    28. When duplicate subpattern names are present (necessarily with different
1073        numbers, as required by 27 above), and a test is made by name in a
1074        conditional pattern, either for a subpattern having been matched, or for
1075        recursion in such a pattern, all the associated numbered subpatterns are
1076        tested, and the overall condition is true if the condition is true for any
1077        one of them. This is the way Perl works, and is also more like the way
1078        testing by number works.
1079    
1080    
1081    Version 7.9 11-Apr-09
1082    ---------------------
1083    
1084    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1085        (pcretest), all targets were linked against these libraries. This included
1086        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1087        libraries. This caused unwanted dependencies to be created. This problem
1088        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1089        pcretest is linked with readline.
1090    
1091    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1092        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1093        moved outside it again, because FALSE and TRUE are already defined in AIX,
1094        but BOOL is not.
1095    
1096    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1097        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1098    
1099    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1100        hyphens) following file names and line numbers when outputting matching
1101        lines. This is not true; no spaces are inserted. I have also clarified the
1102        wording for the --colour (or --color) option.
1103    
1104    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1105        was not coloured; this is different to GNU grep, so I have changed it to be
1106        the same.
1107    
1108    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1109        each matching line was coloured. Now it goes on to look for further matches
1110        of any of the test patterns, which is the same behaviour as GNU grep.
1111    
1112    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1113        doesn't make sense to accept an empty string match in pcregrep, so I have
1114        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1115        seems to be how GNU grep behaves.
1116    
1117    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1118        start or after a newline", because the conditional assertion was not being
1119        correctly handled. The rule now is that both the assertion and what follows
1120        in the first alternative must satisfy the test.
1121    
1122    9.  If auto-callout was enabled in a pattern with a conditional group whose
1123        condition was an assertion, PCRE could crash during matching, both with
1124        pcre_exec() and pcre_dfa_exec().
1125    
1126    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1127        used for matching.
1128    
1129    11. Unicode property support in character classes was not working for
1130        characters (bytes) greater than 127 when not in UTF-8 mode.
1131    
1132    12. Added the -M command line option to pcretest.
1133    
1134    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1135    
1136    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1137    
1138    16. Added comments and documentation about mis-use of no_arg in the C++
1139        wrapper.
1140    
1141    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1142        from Martin Jerabek that uses macro names for all relevant character and
1143        string constants.
1144    
1145    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1146        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1147        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1148        these, but not everybody uses configure.
1149    
1150    19. A conditional group that had only one branch was not being correctly
1151        recognized as an item that could match an empty string. This meant that an
1152        enclosing group might also not be so recognized, causing infinite looping
1153        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1154        with the subject "ab", where knowledge that the repeated group can match
1155        nothing is needed in order to break the loop.
1156    
1157    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1158        exec(), but without supplying a callout function, matching went wrong.
1159    
1160    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1161        leak if the size of the offset vector was greater than 30. When the vector
1162        is smaller, the saved offsets during recursion go onto a local stack
1163        vector, but for larger vectors malloc() is used. It was failing to free
1164        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1165        error, in fact).
1166    
1167    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1168        heapframe that is used only when UTF-8 support is enabled. This caused no
1169        problem, but was untidy.
1170    
1171    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1172        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1173        included within another project.
1174    
1175    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1176        slightly modified by me:
1177    
1178          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1179              not building pcregrep.
1180    
1181          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1182              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1183    
1184    25. Forward references, both numeric and by name, in patterns that made use of
1185        duplicate group numbers, could behave incorrectly or give incorrect errors,
1186        because when scanning forward to find the reference group, PCRE was not
1187        taking into account the duplicate group numbers. A pattern such as
1188        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1189    
1190    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1191        the feature of a custom pointer more persuasive (as requested by a user).
1192    
1193    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1194        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1195        pre-defined.
1196    
1197    28. Added support for (*UTF8) at the start of a pattern.
1198    
1199    29. Arrange for flags added by the "release type" setting in CMake to be shown
1200        in the configuration summary.
1201    
1202    
1203    Version 7.8 05-Sep-08
1204    ---------------------
1205    
1206    1.  Replaced UCP searching code with optimized version as implemented for Ad
1207        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1208        stage table and inline lookup instead of a function, giving speed ups of 2
1209        to 5 times on some simple patterns that I tested. Permission was given to
1210        distribute the MultiStage2.py script that generates the tables (it's not in
1211        the tarball, but is in the Subversion repository).
1212    
1213    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1214        scripts.
1215    
1216    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1217        a group with a zero qualifier. The result of the study could be incorrect,
1218        or the function might crash, depending on the pattern.
1219    
1220    4.  Caseless matching was not working for non-ASCII characters in back
1221        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1222        It now works when Unicode Property Support is available.
1223    
1224    5.  In pcretest, an escape such as \x{de} in the data was always generating
1225        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1226        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1227        truncation.
1228    
1229    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1230    
1231    7.  Added two (int) casts to pcregrep when printing the difference of two
1232        pointers, in case they are 64-bit values.
1233    
1234    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1235        test 2 if it fails.
1236    
1237    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1238        and a #define of that name to empty if it is not externally set. This is to
1239        allow users of MSVC to set it if necessary.
1240    
1241    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1242        the convenience functions in the pcre_get.c source file.
1243    
1244    11. An option change at the start of a pattern that had top-level alternatives
1245        could cause overwriting and/or a crash. This command provoked a crash in
1246        some environments:
1247    
1248          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1249    
1250        This potential security problem was recorded as CVE-2008-2371.
1251    
1252    12. For a pattern where the match had to start at the beginning or immediately
1253        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1254        pcre_dfa_exec() could read past the end of the passed subject if there was
1255        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1256        pcretest so that it places the subject at the end of its malloc-ed buffer.
1257    
1258    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1259        exec() might read past the end of the data buffer in UTF-8 mode.
1260    
1261    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1262        the data contained the byte 0x85 as part of a UTF-8 character within its
1263        first line. This applied both to normal and DFA matching.
1264    
1265    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1266        /^[^d]*?$/8 failed to match "abc".
1267    
1268    16. Added a missing copyright notice to pcrecpp_internal.h.
1269    
1270    17. Make it more clear in the documentation that values returned from
1271        pcre_exec() in ovector are byte offsets, not character counts.
1272    
1273    18. Tidied a few places to stop certain compilers from issuing warnings.
1274    
1275    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1276        supplied by Stefan Weber. I made a further small update for 7.8 because
1277        there is a change of source arrangements: the pcre_searchfuncs.c module is
1278        replaced by pcre_ucd.c.
1279    
1280    
1281    Version 7.7 07-May-08
1282    ---------------------
1283    
1284    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1285        a string to a long long, pretend we don't even have a long long." This is
1286        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1287    
1288    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1289        pre-7.6 versions, which defined a global no_arg variable instead of putting
1290        it in the RE class. (See also #8 below.)
1291    
1292    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1293        Lopes.
1294    
1295    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1296    
1297        (1) The include/exclude patterns were being applied to the whole pathnames
1298            of files, instead of just to the final components.
1299    
1300        (2) If there was more than one level of directory, the subdirectories were
1301            skipped unless they satisfied the include/exclude conditions. This is
1302            inconsistent with GNU grep (and could even be seen as contrary to the
1303            pcregrep specification - which I improved to make it absolutely clear).
1304            The action now is always to scan all levels of directory, and just
1305            apply the include/exclude patterns to regular files.
1306    
1307    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1308        --exclude_dir in the tests to avoid scanning .svn directories.
1309    
1310    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1311        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1312        doesn't support NULs in patterns.
1313    
1314    7.  Added some missing "const"s to declarations of static tables in
1315        pcre_compile.c and pcre_dfa_exec.c.
1316    
1317    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1318        caused by fix #2  above. (Subsequently also a second patch to fix the
1319        first patch. And a third patch - this was a messy problem.)
1320    
1321    9.  Applied Craig's patch to remove the use of push_back().
1322    
1323    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1324        matching function regexec().
1325    
1326    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1327        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1328        references. PCRE supports relative numbers with this syntax (I don't think
1329        Oniguruma does).
1330    
1331    12. Previously, a group with a zero repeat such as (...){0} was completely
1332        omitted from the compiled regex. However, this means that if the group
1333        was called as a subroutine from elsewhere in the pattern, things went wrong
1334        (an internal error was given). Such groups are now left in the compiled
1335        pattern, with a new opcode that causes them to be skipped at execution
1336        time.
1337    
1338    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1339        to the way PCRE behaves:
1340    
1341        (a) A lone ] character is dis-allowed (Perl treats it as data).
1342    
1343        (b) A back reference to an unmatched subpattern matches an empty string
1344            (Perl fails the current match path).
1345    
1346        (c) A data ] in a character class must be notated as \] because if the
1347            first data character in a class is ], it defines an empty class. (In
1348            Perl it is not possible to have an empty class.) The empty class []
1349            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1350            The negative empty class [^] matches any one character, independently
1351            of the DOTALL setting.
1352    
1353    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1354        non-existent subpattern following a character class starting with ']' and
1355        containing () gave an internal compiling error instead of "reference to
1356        non-existent subpattern". Fortunately, when the pattern did exist, the
1357        compiled code was correct. (When scanning forwards to check for the
1358        existencd of the subpattern, it was treating the data ']' as terminating
1359        the class, so got the count wrong. When actually compiling, the reference
1360        was subsequently set up correctly.)
1361    
1362    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1363        it was being rejected as not supported by pcre_dfa_exec(), even though
1364        other assertions are supported. I have made pcre_dfa_exec() support
1365        (*FAIL).
1366    
1367    16. The implementation of 13c above involved the invention of a new opcode,
1368        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1369        cannot be changed at match time, I realized I could make a small
1370        improvement to matching performance by compiling OP_ALLANY instead of
1371        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1372        on the OP_ANY path.
1373    
1374    17. Compiling pcretest on Windows with readline support failed without the
1375        following two fixes: (1) Make the unistd.h include conditional on
1376        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1377    
1378    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1379        ncurses library to be included for pcretest when ReadLine support is
1380        requested, but also to allow for it to be overridden. This patch came from
1381        Daniel Bergström.
1382    
1383    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1384        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1385        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1386        spotting this.
1387    
1388    
1389    Version 7.6 28-Jan-08
1390  ---------------------  ---------------------
1391    
1392  1.  A character class containing a very large number of characters with  1.  A character class containing a very large number of characters with
# Line 37  Version 7.6 21-Jan-08 Line 1422  Version 7.6 21-Jan-08
1422      solves the problem, but it does no harm.      solves the problem, but it does no harm.
1423    
1424  6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and  6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1425      NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured      NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1426      with CMake, and also correct the comment about stack recursion.      with CMake, and also correct the comment about stack recursion.
1427    
1428  7.  Remove the automatic building of pcredemo from the ./configure system and  7.  Remove the automatic building of pcredemo from the ./configure system and
# Line 46  Version 7.6 21-Jan-08 Line 1431  Version 7.6 21-Jan-08
1431      building it automatically is not really right. What is more, it gave      building it automatically is not really right. What is more, it gave
1432      trouble in some build environments.      trouble in some build environments.
1433    
1434    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1435    
1436    
1437  Version 7.5 10-Jan-08  Version 7.5 10-Jan-08
1438  ---------------------  ---------------------

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