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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.7 05-Mar-08  Version 8.30
5    ------------
6    
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
9    
10    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
11        only in quite long subpatterns.
12    
13    3.  Removed the function pcre_info(), which has been obsolete and deprecated
14        since it was replaced by pcre_fullinfo() in February 2000.
15    
16    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
17        match a (*MARK), and the match failed at the start of the subject, a
18        reference to memory before the start of the subject could occur. This bug
19        was introduced by fix 17 of release 8.21.
20    
21    5.  A reference to an unset group with zero minimum repetition was giving
22        totally wrong answers (in non-JavaScript-compatibility mode). For example,
23        /(another)?(\1?)test/ matched against "hello world test". This bug was
24        introduced in release 8.13.
25    
26    6.  Add support for 16-bit character strings (a large amount of work involving
27        many changes and refactorings).
28    
29    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
30        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
31        from a file.
32    
33    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
34        rounding is not applied in this particular case).
35    
36    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
37        if they appear, or are escaped, in patterns.
38    
39    10. Get rid of a number of -Wunused-but-set-variable warnings.
40    
41    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
42        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
43        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
44        also returns the mark "x". This bug applied to capturing parentheses,
45        non-capturing parentheses, and atomic parentheses.
46    
47    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
48        information out of configure.ac instead of relying on pcre.h.generic, which
49        is not stored in the repository.
50    
51    
52    Version 8.21 12-Dec-2011
53    ------------------------
54    
55    1.  Updating the JIT compiler.
56    
57    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
58        are added as well.
59    
60    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
61        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
62        calling _pcre_jit_exec. Some extra comments are added.
63    
64    4.  (*MARK) settings inside atomic groups that do not contain any capturing
65        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
66        was introduced by change 18 for 8.20.
67    
68    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
69        ECMA-262 standard.
70    
71    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
72        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
73        This bug was probably introduced by change 9 of 8.13.
74    
75    7.  While fixing 6 above, I noticed that a number of other items were being
76        incorrectly rejected as "not fixed length". This arose partly because newer
77        opcodes had not been added to the fixed-length checking code. I have (a)
78        corrected the bug and added tests for these items, and (b) arranged for an
79        error to occur if an unknown opcode is encountered while checking for fixed
80        length instead of just assuming "not fixed length". The items that were
81        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
82        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
83        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
84    
85    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
86        being incorrectly compiled and would have given unpredicatble results.
87    
88    9.  A possessively repeated subpattern with minimum repeat count greater than
89        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
90        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
91        the first (A) could occur when it should not.
92    
93    10. Add a cast and remove a redundant test from the code.
94    
95    11. JIT should use pcre_malloc/pcre_free for allocation.
96    
97    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
98        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
99        is anything other than /usr, -L is still shown).
100    
101    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
102    
103    14. Perl does not support \N without a following name in a [] class; PCRE now
104        also gives an error.
105    
106    15. If a forward reference was repeated with an upper limit of around 2000,
107        it caused the error "internal error: overran compiling workspace". The
108        maximum number of forward references (including repeats) was limited by the
109        internal workspace, and dependent on the LINK_SIZE. The code has been
110        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
111        the default depends on LINK_SIZE. There is a new upper limit (for safety)
112        of around 200,000 forward references. While doing this, I also speeded up
113        the filling in of repeated forward references.
114    
115    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
116        incorrectly expecting the subject to contain another "a" after the start.
117    
118    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
119        in the match, the SKIP should be ignored. This was not happening; instead
120        the SKIP was being treated as NOMATCH. For patterns such as
121        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
122        tested.
123    
124    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
125        now much more compatible with Perl, in particular in cases where the result
126        is a non-match for a non-anchored pattern. For example, if
127        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
128        "m", where previously it did not return a name. A side effect of this
129        change is that for partial matches, the last encountered mark name is
130        returned, as for non matches. A number of tests that were previously not
131        Perl-compatible have been moved into the Perl-compatible test files. The
132        refactoring has had the pleasing side effect of removing one argument from
133        the match() function, thus reducing its stack requirements.
134    
135    19. If the /S+ option was used in pcretest to study a pattern using JIT,
136        subsequent uses of /S (without +) incorrectly behaved like /S+.
137    
138    21. Retrieve executable code size support for the JIT compiler and fixing
139        some warnings.
140    
141    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
142        not work when the shorter character appeared right at the end of the
143        subject string.
144    
145    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
146        systems.
147    
148    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
149        output it when the /M option is used in pcretest.
150    
151    25. The CheckMan script was not being included in the distribution. Also, added
152        an explicit "perl" to run Perl scripts from the PrepareRelease script
153        because this is reportedly needed in Windows.
154    
155    26. If study data was being save in a file and studying had not found a set of
156        "starts with" bytes for the pattern, the data written to the file (though
157        never used) was taken from uninitialized memory and so caused valgrind to
158        complain.
159    
160    27. Updated RunTest.bat as provided by Sheri Pierce.
161    
162    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
163    
164    29. Computation of memory usage for the table of capturing group names was
165        giving an unnecessarily large value.
166    
167    
168    Version 8.20 21-Oct-2011
169    ------------------------
170    
171    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
172        a POSIX class. After further experiments with Perl, which convinced me that
173        Perl has bugs and confusions, a closing square bracket is no longer allowed
174        in a POSIX name. This bug also affected patterns with classes that started
175        with full stops.
176    
177    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
178        captured substring, but while checking the failing first alternative,
179        substring 1 is temporarily captured. If the output vector supplied to
180        pcre_exec() was not big enough for this capture, the yield of the function
181        was still zero ("insufficient space for captured substrings"). This cannot
182        be totally fixed without adding another stack variable, which seems a lot
183        of expense for a edge case. However, I have improved the situation in cases
184        such as /(a)(b)x|abc/ matched against "abc", where the return code
185        indicates that fewer than the maximum number of slots in the ovector have
186        been set.
187    
188    3.  Related to (2) above: when there are more back references in a pattern than
189        slots in the output vector, pcre_exec() uses temporary memory during
190        matching, and copies in the captures as far as possible afterwards. It was
191        using the entire output vector, but this conflicts with the specification
192        that only 2/3 is used for passing back captured substrings. Now it uses
193        only the first 2/3, for compatibility. This is, of course, another edge
194        case.
195    
196    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
197        main code base, and can be used by building with --enable-jit. When this is
198        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
199        runtime --no-jit option is given.
200    
201    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
202        ovector, the return from the function was zero, implying that there were
203        other matches that did not fit. The correct "exactly full" value is now
204        returned.
205    
206    6.  If a subpattern that was called recursively or as a subroutine contained
207        (*PRUNE) or any other control that caused it to give a non-standard return,
208        invalid errors such as "Error -26 (nested recursion at the same subject
209        position)" or even infinite loops could occur.
210    
211    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
212        computing the minimum length on reaching *ACCEPT, and so ended up with the
213        wrong value of 1 rather than 0. Further investigation indicates that
214        computing a minimum subject length in the presence of *ACCEPT is difficult
215        (think back references, subroutine calls), and so I have changed the code
216        so that no minimum is registered for a pattern that contains *ACCEPT.
217    
218    8.  If (*THEN) was present in the first (true) branch of a conditional group,
219        it was not handled as intended. [But see 16 below.]
220    
221    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
222        Sheri Pierce.
223    
224    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
225        the first byte in a match must be "a".
226    
227    11. Change 17 for 8.13 increased the recursion depth for patterns like
228        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
229        pattern contains any instances of (*THEN). If it does not, the old
230        optimizations are restored. It would be nice to do this on a per-group
231        basis, but at the moment that is not feasible.
232    
233    12. In some environments, the output of pcretest -C is CRLF terminated. This
234        broke RunTest's code that checks for the link size. A single white space
235        character after the value is now allowed for.
236    
237    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
238        For "fr", it uses the Windows-specific input and output files.
239    
240    14. If (*THEN) appeared in a group that was called recursively or as a
241        subroutine, it did not work as intended. [But see next item.]
242    
243    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
244        pattern fragments (but not containing any | characters). If A and B are
245        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
246        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
247        D. In other words, Perl considers parentheses that do not contain any |
248        characters to be part of a surrounding alternative, whereas PCRE was
249        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
250        differently. PCRE now behaves in the same way as Perl, except in the case
251        of subroutine/recursion calls such as (?1) which have in any case always
252        been different (but PCRE had them first :-).
253    
254    16. Related to 15 above: Perl does not treat the | in a conditional group as
255        creating alternatives. Such a group is treated in the same way as an
256        ordinary group without any | characters when processing (*THEN). PCRE has
257        been changed to match Perl's behaviour.
258    
259    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
260        RunGrepTest script failed.
261    
262    18. Change 22 for version 13 caused atomic groups to use more stack. This is
263        inevitable for groups that contain captures, but it can lead to a lot of
264        stack use in large patterns. The old behaviour has been restored for atomic
265        groups that do not contain any capturing parentheses.
266    
267    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
268        suppress the check for a minimum subject length at run time. (If it was
269        given to pcre_exec() or pcre_dfa_exec() it did work.)
270    
271    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
272        fail to work when decoding hex characters in data strings in EBCDIC
273        environments.
274    
275    21. It appears that in at least one Mac OS environment, the isxdigit() function
276        is implemented as a macro that evaluates to its argument more than once,
277        contravening the C 90 Standard (I haven't checked a later standard). There
278        was an instance in pcretest which caused it to go wrong when processing
279        \x{...} escapes in subject strings. The has been rewritten to avoid using
280        things like p++ in the argument of isxdigit().
281    
282    
283    Version 8.13 16-Aug-2011
284    ------------------------
285    
286    1.  The Unicode data tables have been updated to Unicode 6.0.0.
287    
288    2.  Two minor typos in pcre_internal.h have been fixed.
289    
290    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
291        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
292        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
293    
294    4.  There were a number of related bugs in the code for matching backrefences
295        caselessly in UTF-8 mode when codes for the characters concerned were
296        different numbers of bytes. For example, U+023A and U+2C65 are an upper
297        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
298        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
299        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
300        2-byte code at the end of the subject (it thought there wasn't enough data
301        left).
302    
303    5.  Comprehensive information about what went wrong is now returned by
304        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
305        as the output vector has at least 2 elements. The offset of the start of
306        the failing character and a reason code are placed in the vector.
307    
308    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
309        now returned is for the first byte of the failing character, instead of the
310        last byte inspected. This is an incompatible change, but I hope it is small
311        enough not to be a problem. It makes the returned offset consistent with
312        pcre_exec() and pcre_dfa_exec().
313    
314    7.  pcretest now gives a text phrase as well as the error number when
315        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
316        failure, the offset and reason code are output.
317    
318    8.  When \R was used with a maximizing quantifier it failed to skip backwards
319        over a \r\n pair if the subsequent match failed. Instead, it just skipped
320        back over a single character (\n). This seems wrong (because it treated the
321        two characters as a single entity when going forwards), conflicts with the
322        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
323        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
324        has been changed.
325    
326    9.  Some internal refactoring has changed the processing so that the handling
327        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
328        time (the PCRE_DOTALL option was changed this way some time ago: version
329        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
330        which was always a bit of a fudge. It also means that there is one less
331        argument for the match() function, which reduces its stack requirements
332        slightly. This change also fixes an incompatibility with Perl: the pattern
333        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
334    
335    10. More internal refactoring has drastically reduced the number of recursive
336        calls to match() for possessively repeated groups such as (abc)++ when
337        using pcre_exec().
338    
339    11. While implementing 10, a number of bugs in the handling of groups were
340        discovered and fixed:
341    
342        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
343        (a|)*(?1) gave a compile-time internal error.
344        ((a|)+)+  did not notice that the outer group could match an empty string.
345        (^a|^)+   was not marked as anchored.
346        (.*a|.*)+ was not marked as matching at start or after a newline.
347    
348    12. Yet more internal refactoring has removed another argument from the match()
349        function. Special calls to this function are now indicated by setting a
350        value in a variable in the "match data" data block.
351    
352    13. Be more explicit in pcre_study() instead of relying on "default" for
353        opcodes that mean there is no starting character; this means that when new
354        ones are added and accidentally left out of pcre_study(), testing should
355        pick them up.
356    
357    14. The -s option of pcretest has been documented for ages as being an old
358        synonym of -m (show memory usage). I have changed it to mean "force study
359        for every regex", that is, assume /S for every regex. This is similar to -i
360        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
361        using it. It makes it easier to run collections of tests with and without
362        study enabled, and thereby test pcre_study() more easily. All the standard
363        tests are now run with and without -s (but some patterns can be marked as
364        "never study" - see 20 below).
365    
366    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
367        restoration of the capturing data to the outer values was not happening
368        correctly.
369    
370    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
371        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
372        pattern had matched an empty string, and so incorrectly returned a no
373        match.
374    
375    17. There was optimizing code for the last branch of non-capturing parentheses,
376        and also for the obeyed branch of a conditional subexpression, which used
377        tail recursion to cut down on stack usage. Unfortunately, now that there is
378        the possibility of (*THEN) occurring in these branches, tail recursion is
379        no longer possible because the return has to be checked for (*THEN). These
380        two optimizations have therefore been removed. [But see 8.20/11 above.]
381    
382    18. If a pattern containing \R was studied, it was assumed that \R always
383        matched two bytes, thus causing the minimum subject length to be
384        incorrectly computed because \R can also match just one byte.
385    
386    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
387        was incorrectly computed.
388    
389    20. If /S is present twice on a test pattern in pcretest input, it now
390        *disables* studying, thereby overriding the use of -s on the command line
391        (see 14 above). This is necessary for one or two tests to keep the output
392        identical in both cases.
393    
394    21. When (*ACCEPT) was used in an assertion that matched an empty string and
395        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
396    
397    22. When an atomic group that contained a capturing parenthesis was
398        successfully matched, but the branch in which it appeared failed, the
399        capturing was not being forgotten if a higher numbered group was later
400        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
401        group 1 to "a", when in fact it should be unset. This applied to multi-
402        branched capturing and non-capturing groups, repeated or not, and also to
403        positive assertions (capturing in negative assertions does not happen
404        in PCRE) and also to nested atomic groups.
405    
406    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
407        subject after a captured substring, to make it easier to tell which of a
408        number of identical substrings has been captured.
409    
410    24. The way atomic groups are processed by pcre_exec() has been changed so that
411        if they are repeated, backtracking one repetition now resets captured
412        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
413        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
414        "aaa". Previously, it would have been "a". As part of this code
415        refactoring, the way recursive calls are handled has also been changed.
416    
417    25. If an assertion condition captured any substrings, they were not passed
418        back unless some other capturing happened later. For example, if
419        (?(?=(a))a) was matched against "a", no capturing was returned.
420    
421    26. When studying a pattern that contained subroutine calls or assertions,
422        the code for finding the minimum length of a possible match was handling
423        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
424        group 1 called group 2 while simultaneously a separate group 2 called group
425        1). A stack overflow occurred in this case. I have fixed this by limiting
426        the recursion depth to 10.
427    
428    27. Updated RunTest.bat in the distribution to the version supplied by Tom
429        Fortmann. This supports explicit test numbers on the command line, and has
430        argument validation and error reporting.
431    
432    28. An instance of \X with an unlimited repeat could fail if at any point the
433        first character it looked at was a mark character.
434    
435    29. Some minor code refactoring concerning Unicode properties and scripts
436        should reduce the stack requirement of match() slightly.
437    
438    30. Added the '=' option to pcretest to check the setting of unused capturing
439        slots at the end of the pattern, which are documented as being -1, but are
440        not included in the return count.
441    
442    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
443        compiled something random. Now it gives a compile-time error (as does
444        Perl).
445    
446    32. A *MARK encountered during the processing of a positive assertion is now
447        recorded and passed back (compatible with Perl).
448    
449    33. If --only-matching or --colour was set on a pcregrep call whose pattern
450        had alternative anchored branches, the search for a second match in a line
451        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
452        matched the line "0102" twice. The same bug affected patterns that started
453        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
454        twice.
455    
456    34. Previously, PCRE did not allow quantification of assertions. However, Perl
457        does, and because of capturing effects, quantifying parenthesized
458        assertions may at times be useful. Quantifiers are now allowed for
459        parenthesized assertions.
460    
461    35. A minor code tidy in pcre_compile() when checking options for \R usage.
462    
463    36. \g was being checked for fancy things in a character class, when it should
464        just be a literal "g".
465    
466    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
467        appearance of a nested POSIX class supersedes an apparent external class.
468        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
469        unescaped square brackets may also appear as part of class names. For
470        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
471        more like Perl. (But see 8.20/1 above.)
472    
473    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
474        was because it thought it was \N{name}, which is not supported).
475    
476    39. Add minix to OS list not supporting the -S option in pcretest.
477    
478    40. PCRE tries to detect cases of infinite recursion at compile time, but it
479        cannot analyze patterns in sufficient detail to catch mutual recursions
480        such as ((?1))((?2)). There is now a runtime test that gives an error if a
481        subgroup is called recursively as a subpattern for a second time at the
482        same position in the subject string. In previous releases this might have
483        been caught by the recursion limit, or it might have run out of stack.
484    
485    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
486        happen only once. PCRE was, however incorrectly giving a compile time error
487        "recursive call could loop indefinitely" because it cannot analyze the
488        pattern in sufficient detail. The compile time test no longer happens when
489        PCRE is compiling a conditional subpattern, but actual runaway loops are
490        now caught at runtime (see 40 above).
491    
492    42. It seems that Perl allows any characters other than a closing parenthesis
493        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
494        has been changed to be the same.
495    
496    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
497        as not to get warnings when autogen.sh is called. Also changed
498        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
499    
500    44. To help people who use pcregrep to scan files containing exceedingly long
501        lines, the following changes have been made:
502    
503        (a) The default value of the buffer size parameter has been increased from
504            8K to 20K. (The actual buffer used is three times this size.)
505    
506        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
507            PCRE is built.
508    
509        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
510            to be set at run time.
511    
512        (d) Numerical values in pcregrep options can be followed by K or M, for
513            example --buffer-size=50K.
514    
515        (e) If a line being scanned overflows pcregrep's buffer, an error is now
516            given and the return code is set to 2.
517    
518    45. Add a pointer to the latest mark to the callout data block.
519    
520    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
521        partial match of an empty string instead of no match. This was specific to
522        the use of ".".
523    
524    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
525        complete match instead of a partial match. This bug was dependent on both
526        the PCRE_UTF8 and PCRE_DOTALL options being set.
527    
528    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
529        starting byte set, because \b was not being ignored.
530    
531    
532    Version 8.12 15-Jan-2011
533    ------------------------
534    
535    1.  Fixed some typos in the markup of the man pages, and wrote a script that
536        checks for such things as part of the documentation building process.
537    
538    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
539        --match-limit and --recursion-limit options (added for 8.11). In
540        particular, this made one of the standard tests fail. (The integer value
541        went into the wrong half of a long int.)
542    
543    3.  If the --colour option was given to pcregrep with -v (invert match), it
544        did strange things, either producing crazy output, or crashing. It should,
545        of course, ignore a request for colour when reporting lines that do not
546        match.
547    
548    4.  Another pcregrep bug caused similar problems if --colour was specified with
549        -M (multiline) and the pattern match finished with a line ending.
550    
551    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
552        matched in multiline mode, the following line was shown as part of the
553        match. This seems wrong, so I have changed it.
554    
555    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
556        the check for further matches in the same line (so they could be coloured)
557        to overrun the end of the current line. If another match was found, it was
558        incorrectly shown (and then shown again when found in the next line).
559    
560    7.  If pcregrep was compiled under Windows, there was a reference to the
561        function pcregrep_exit() before it was defined. I am assuming this was
562        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
563        reported by a user. I've moved the definition above the reference.
564    
565    
566    Version 8.11 10-Dec-2010
567    ------------------------
568    
569    1.  (*THEN) was not working properly if there were untried alternatives prior
570        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
571        backtracked to try for "b" instead of moving to the next alternative branch
572        at the same level (in this case, to look for "c"). The Perl documentation
573        is clear that when (*THEN) is backtracked onto, it goes to the "next
574        alternative in the innermost enclosing group".
575    
576    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
577        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
578        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
579        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
580        (*THEN).
581    
582    3.  If \s appeared in a character class, it removed the VT character from
583        the class, even if it had been included by some previous item, for example
584        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
585        of \s, but is part of the POSIX "space" class.)
586    
587    4.  A partial match never returns an empty string (because you can always
588        match an empty string at the end of the subject); however the checking for
589        an empty string was starting at the "start of match" point. This has been
590        changed to the "earliest inspected character" point, because the returned
591        data for a partial match starts at this character. This means that, for
592        example, /(?<=abc)def/ gives a partial match for the subject "abc"
593        (previously it gave "no match").
594    
595    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
596        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
597        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
598        has an implication that the given string is incomplete (because a partial
599        match is preferred over a full match). For this reason, these items now
600        give a partial match in this situation. [Aside: previously, the one case
601        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
602        match rather than a full match, which was wrong by the old rules, but is
603        now correct.]
604    
605    6.  There was a bug in the handling of #-introduced comments, recognized when
606        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
607        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
608        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
609        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
610        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
611        places in pcre_compile().
612    
613    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
614        comments when looking ahead for named forward references to subpatterns,
615        the only newline sequence it recognized was NL. It now handles newlines
616        according to the set newline convention.
617    
618    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
619        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
620        cater for a lack of strerror(). These oversights have been fixed.
621    
622    9.  Added --match-limit and --recursion-limit to pcregrep.
623    
624    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
625    
626    11. When the -o option was used, pcregrep was setting a return code of 1, even
627        when matches were found, and --line-buffered was not being honoured.
628    
629    12. Added an optional parentheses number to the -o and --only-matching options
630        of pcregrep.
631    
632    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
633        can match an empty string. The code to do it in pcretest and pcredemo
634        needed fixing:
635    
636        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
637            only one byte after an empty string match just before CRLF (this case
638            just got forgotten; "any" and "anycrlf" were OK).
639    
640        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
641            mode when an empty string match preceded an ASCII character followed by
642            a non-ASCII character. (The code for advancing by one character rather
643            than one byte was nonsense.)
644    
645        (c) The pcredemo.c sample program did not have any code at all to handle
646            the cases when CRLF is a valid newline sequence.
647    
648    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
649        as a starting offset was within the subject string. There is now a new
650        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
651        negative or greater than the length of the string. In order to test this,
652        pcretest is extended to allow the setting of negative starting offsets.
653    
654    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
655        starting offset points to the beginning of a UTF-8 character was
656        unnecessarily clumsy. I tidied it up.
657    
658    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
659        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
660    
661    17. Nobody had reported that the --include_dir option, which was added in
662        release 7.7 should have been called --include-dir (hyphen, not underscore)
663        for compatibility with GNU grep. I have changed it to --include-dir, but
664        left --include_dir as an undocumented synonym, and the same for
665        --exclude-dir, though that is not available in GNU grep, at least as of
666        release 2.5.4.
667    
668    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
669        characters from a string of bytes) have been redefined so as not to use
670        loops, in order to improve performance in some environments. At the same
671        time, I abstracted some of the common code into auxiliary macros to save
672        repetition (this should not affect the compiled code).
673    
674    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
675        compile-time error is now given if \c is not followed by an ASCII
676        character, that is, a byte less than 128. (In EBCDIC mode, the code is
677        different, and any byte value is allowed.)
678    
679    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
680        START_OPTIMIZE option, which is now allowed at compile time - but just
681        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
682        to pcregrep and other applications that have no direct access to PCRE
683        options. The new /Y option in pcretest sets this option when calling
684        pcre_compile().
685    
686    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
687        back references. Groups containing recursive back references were forced to
688        be atomic by that change, but in the case of named groups, the amount of
689        memory required was incorrectly computed, leading to "Failed: internal
690        error: code overflow". This has been fixed.
691    
692    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
693        pcretest.c, to avoid build problems in some Borland environments.
694    
695    
696    Version 8.10 25-Jun-2010
697    ------------------------
698    
699    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
700        THEN.
701    
702    2.  (*ACCEPT) was not working when inside an atomic group.
703    
704    3.  Inside a character class, \B is treated as a literal by default, but
705        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
706        causes the error). The code is unchanged, but I tidied the documentation.
707    
708    4.  Inside a character class, PCRE always treated \R and \X as literals,
709        whereas Perl faults them if its -w option is set. I have changed PCRE so
710        that it faults them when PCRE_EXTRA is set.
711    
712    5.  Added support for \N, which always matches any character other than
713        newline. (It is the same as "." when PCRE_DOTALL is not set.)
714    
715    6.  When compiling pcregrep with newer versions of gcc which may have
716        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
717        declared with attribute warn_unused_result" were given. Just casting the
718        result to (void) does not stop the warnings; a more elaborate fudge is
719        needed. I've used a macro to implement this.
720    
721    7.  Minor change to pcretest.c to avoid a compiler warning.
722    
723    8.  Added four artifical Unicode properties to help with an option to make
724        \s etc use properties (see next item). The new properties are: Xan
725        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
726    
727    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
728        use Unicode properties. (*UCP) at the start of a pattern can be used to set
729        this option. Modified pcretest to add /W to test this facility. Added
730        REG_UCP to make it available via the POSIX interface.
731    
732    10. Added --line-buffered to pcregrep.
733    
734    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
735        studied, and the match started with a letter with a code point greater than
736        127 whose first byte was different to the first byte of the other case of
737        the letter, the other case of this starting letter was not recognized
738        (#976).
739    
740    12. If a pattern that was studied started with a repeated Unicode property
741        test, for example, \p{Nd}+, there was the theoretical possibility of
742        setting up an incorrect bitmap of starting bytes, but fortunately it could
743        not have actually happened in practice until change 8 above was made (it
744        added property types that matched character-matching opcodes).
745    
746    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
747        possible starting bytes for non-anchored patterns.
748    
749    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
750        \R, and also a number of cases that involve Unicode properties, both
751        explicit and implicit when PCRE_UCP is set.
752    
753    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
754        input, it could crash or give wrong results if characters with values
755        greater than 0xc0 were present in the subject string. (Detail: it assumed
756        UTF-8 input when processing these items.)
757    
758    16. Added a lot of (int) casts to avoid compiler warnings in systems where
759        size_t is 64-bit (#991).
760    
761    17. Added a check for running out of memory when PCRE is compiled with
762        --disable-stack-for-recursion (#990).
763    
764    18. If the last data line in a file for pcretest does not have a newline on
765        the end, a newline was missing in the output.
766    
767    19. The default pcre_chartables.c file recognizes only ASCII characters (values
768        less than 128) in its various bitmaps. However, there is a facility for
769        generating tables according to the current locale when PCRE is compiled. It
770        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
771        characters, are recognized by isspace() and therefore were getting set in
772        these tables, and indeed these tables seem to approximate to ISO 8859. This
773        caused a problem in UTF-8 mode when pcre_study() was used to create a list
774        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
775        which of course cannot start UTF-8 characters. I have changed the code so
776        that only real ASCII characters (less than 128) and the correct starting
777        bytes for UTF-8 encodings are set for characters greater than 127 when in
778        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
779        altogether.)
780    
781    20. Added the /T option to pcretest so as to be able to run tests with non-
782        standard character tables, thus making it possible to include the tests
783        used for 19 above in the standard set of tests.
784    
785    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
786        reference to a subpattern the other side of a comment that contains an
787        opening parenthesis caused either an internal compiling error, or a
788        reference to the wrong subpattern.
789    
790    
791    Version 8.02 19-Mar-2010
792    ------------------------
793    
794    1.  The Unicode data tables have been updated to Unicode 5.2.0.
795    
796    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
797        configured.
798    
799    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
800        original author of that file, following a query about its status.
801    
802    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
803        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
804    
805    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
806        quantifier applied to a forward-referencing subroutine call, could compile
807        incorrect code or give the error "internal error: previously-checked
808        referenced subpattern not found".
809    
810    6.  Both MS Visual Studio and Symbian OS have problems with initializing
811        variables to point to external functions. For these systems, therefore,
812        pcre_malloc etc. are now initialized to local functions that call the
813        relevant global functions.
814    
815    7.  There were two entries missing in the vectors called coptable and poptable
816        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
817        I've fixed the data, and added a kludgy way of testing at compile time that
818        the lengths are correct (equal to the number of opcodes).
819    
820    8.  Following on from 7, I added a similar kludge to check the length of the
821        eint vector in pcreposix.c.
822    
823    9.  Error texts for pcre_compile() are held as one long string to avoid too
824        much relocation at load time. To find a text, the string is searched,
825        counting zeros. There was no check for running off the end of the string,
826        which could happen if a new error number was added without updating the
827        string.
828    
829    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
830    
831    11. \K was not working if it appeared in an atomic group or in a group that
832        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
833        \K is "not well defined" if used in an assertion. PCRE now accepts it if
834        the assertion is positive, but not if it is negative.
835    
836    12. Change 11 fortuitously reduced the size of the stack frame used in the
837        "match()" function of pcre_exec.c by one pointer. Forthcoming
838        implementation of support for (*MARK) will need an extra pointer on the
839        stack; I have reserved it now, so that the stack frame size does not
840        decrease.
841    
842    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
843        item in branch that calls a recursion is a subroutine call - as in the
844        second branch in the above example - was incorrectly given the compile-
845        time error "recursive call could loop indefinitely" because pcre_compile()
846        was not correctly checking the subroutine for matching a non-empty string.
847    
848    14. The checks for overrunning compiling workspace could trigger after an
849        overrun had occurred. This is a "should never occur" error, but it can be
850        triggered by pathological patterns such as hundreds of nested parentheses.
851        The checks now trigger 100 bytes before the end of the workspace.
852    
853    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
854    
855    
856    Version 8.01 19-Jan-2010
857    ------------------------
858    
859    1.  If a pattern contained a conditional subpattern with only one branch (in
860        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
861        computed the wrong minimum data length (which is of course zero for such
862        subpatterns). This could cause incorrect "no match" results.
863    
864    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
865        the pattern is reset in the first branch, pcre_compile() failed with
866        "internal error: code overflow at offset...". This happened only when
867        the reset was to the original external option setting. (An optimization
868        abstracts leading options settings into an external setting, which was the
869        cause of this.)
870    
871    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
872        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
873        assertion pattern did not match (meaning that the assertion was true), it
874        was incorrectly treated as false if the SKIP had been reached during the
875        matching. This also applied to assertions used as conditions.
876    
877    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
878        assertion subpattern, including such a pattern used as a condition,
879        unpredictable results occurred, instead of the error return
880        PCRE_ERROR_DFA_UITEM.
881    
882    5.  The C++ GlobalReplace function was not working like Perl for the special
883        situation when an empty string is matched. It now does the fancy magic
884        stuff that is necessary.
885    
886    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
887        removed. (These were left over from very, very early versions of PCRE.)
888    
889    7.  Some cosmetic changes to the code to make life easier when compiling it
890        as part of something else:
891    
892        (a) Change DEBUG to PCRE_DEBUG.
893    
894        (b) In pcre_compile(), rename the member of the "branch_chain" structure
895            called "current" as "current_branch", to prevent a collision with the
896            Linux macro when compiled as a kernel module.
897    
898        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
899            prevent a collision with the Linux macro when compiled as a kernel
900            module.
901    
902    8.  In pcre_compile() there are some checks for integer overflows that used to
903        cast potentially large values to (double). This has been changed to that
904        when building, a check for int64_t is made, and if it is found, it is used
905        instead, thus avoiding the use of floating point arithmetic. (There is no
906        other use of FP in PCRE.) If int64_t is not found, the fallback is to
907        double.
908    
909    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
910        2005 (difference between two addresses compared to an unsigned value).
911    
912    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
913        custom one, because of the following reported problem in Windows:
914    
915          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
916              under Win32.
917          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
918              therefore missing the function definition.
919          - The compiler thus generates a "C" signature for the test function.
920          - The linker fails to find the "C" function.
921          - PCRE fails to configure if asked to do so against libbz2.
922    
923    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
924        messages were output:
925    
926          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
927          rerunning libtoolize, to keep the correct libtool macros in-tree.
928          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
929    
930        I have done both of these things.
931    
932    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
933        most of the time, it *can* run out if it is given a pattern that contains a
934        runaway infinite recursion. I updated the discussion in the pcrestack man
935        page.
936    
937    13. Now that we have gone to the x.xx style of version numbers, the minor
938        version may start with zero. Using 08 or 09 is a bad idea because users
939        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
940        interpreted as invalid octal numbers. I've updated the previous comment in
941        configure.ac, and also added a check that gives an error if 08 or 09 are
942        used.
943    
944    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
945        causing partial matching to fail when the end of the subject matched \W
946        in a UTF-8 pattern where \W was quantified with a minimum of 3.
947    
948    15. There were some discrepancies between the declarations in pcre_internal.h
949        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
950        their definitions. The declarations used "const uschar *" and the
951        definitions used USPTR. Even though USPTR is normally defined as "const
952        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
953        reported that: "This difference in casting confuses some C++ compilers, for
954        example, SunCC recognizes above declarations as different functions and
955        generates broken code for hbpcre." I have changed the declarations to use
956        USPTR.
957    
958    16. GNU libtool is named differently on some systems. The autogen.sh script now
959        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
960        (FreeBSD).
961    
962    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
963        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
964        comment: "Figure out how to create a longlong from a string: strtoll and
965        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
966        instance, but it only takes 2 args instead of 3!"
967    
968    18. A subtle bug concerned with back references has been fixed by a change of
969        specification, with a corresponding code fix. A pattern such as
970        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
971        refers, was giving matches when it shouldn't. For example, xa=xaaa would
972        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
973        same bug. Such groups have to be quantified to be useful, or contained
974        inside another quantified group. (If there's no repetition, the reference
975        can never match.) The problem arises because, having left the group and
976        moved on to the rest of the pattern, a later failure that backtracks into
977        the group uses the captured value from the final iteration of the group
978        rather than the correct earlier one. I have fixed this in PCRE by forcing
979        any group that contains a reference to itself to be an atomic group; that
980        is, there cannot be any backtracking into it once it has completed. This is
981        similar to recursive and subroutine calls.
982    
983    
984    Version 8.00 19-Oct-09
985    ----------------------
986    
987    1.  The table for translating pcre_compile() error codes into POSIX error codes
988        was out-of-date, and there was no check on the pcre_compile() error code
989        being within the table. This could lead to an OK return being given in
990        error.
991    
992    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
993        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
994        in a Windows environment.
995    
996    3.  The pcregrep --count option prints the count for each file even when it is
997        zero, as does GNU grep. However, pcregrep was also printing all files when
998        --files-with-matches was added. Now, when both options are given, it prints
999        counts only for those files that have at least one match. (GNU grep just
1000        prints the file name in this circumstance, but including the count seems
1001        more useful - otherwise, why use --count?) Also ensured that the
1002        combination -clh just lists non-zero counts, with no names.
1003    
1004    4.  The long form of the pcregrep -F option was incorrectly implemented as
1005        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1006        but it seems right to fix it, and I didn't think it was worth preserving
1007        the old behaviour.
1008    
1009    5.  The command line items --regex=pattern and --regexp=pattern were not
1010        recognized by pcregrep, which required --regex pattern or --regexp pattern
1011        (with a space rather than an '='). The man page documented the '=' forms,
1012        which are compatible with GNU grep; these now work.
1013    
1014    6.  No libpcreposix.pc file was created for pkg-config; there was just
1015        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1016    
1017    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1018        when UCP support is not needed, by modifying the Python script that
1019        generates it from Unicode data files. This should not matter if the module
1020        is correctly used as a library, but I received one complaint about 50K of
1021        unwanted data. My guess is that the person linked everything into his
1022        program rather than using a library. Anyway, it does no harm.
1023    
1024    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1025        was a minimum greater than 1 for a wide character in a possessive
1026        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1027        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1028        character. Chaos in the form of incorrect output or a compiling loop could
1029        result.
1030    
1031    9.  The restrictions on what a pattern can contain when partial matching is
1032        requested for pcre_exec() have been removed. All patterns can now be
1033        partially matched by this function. In addition, if there are at least two
1034        slots in the offset vector, the offset of the earliest inspected character
1035        for the match and the offset of the end of the subject are set in them when
1036        PCRE_ERROR_PARTIAL is returned.
1037    
1038    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1039        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1040        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1041        and may be more useful for multi-segment matching.
1042    
1043    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1044        used to be given if ever the end of the subject was reached; now it is
1045        given only if matching could not proceed because another character was
1046        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1047        string "Z", which now yields "no match" instead of "partial match". In the
1048        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1049        final character ended with (*FAIL).
1050    
1051    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1052        if the pattern had a "must contain" character that was already found in the
1053        earlier partial match, unless partial matching was again requested. For
1054        example, with the pattern /dog.(body)?/, the "must contain" character is
1055        "g". If the first part-match was for the string "dog", restarting with
1056        "sbody" failed. This bug has been fixed.
1057    
1058    13. The string returned by pcre_dfa_exec() after a partial match has been
1059        changed so that it starts at the first inspected character rather than the
1060        first character of the match. This makes a difference only if the pattern
1061        starts with a lookbehind assertion or \b or \B (\K is not supported by
1062        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1063        matching functions compatible, and I think it's the right thing to do.
1064    
1065    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1066        so that the demonstration program is easily available in environments where
1067        PCRE has not been installed from source.
1068    
1069    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1070        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1071        library.
1072    
1073    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1074        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1075        is not the first non-POSIX option to be added. Clearly some people find
1076        these options useful.
1077    
1078    17. If a caller to the POSIX matching function regexec() passes a non-zero
1079        value for nmatch with a NULL value for pmatch, the value of
1080        nmatch is forced to zero.
1081    
1082    18. RunGrepTest did not have a test for the availability of the -u option of
1083        the diff command, as RunTest does. It now checks in the same way as
1084        RunTest, and also checks for the -b option.
1085    
1086    19. If an odd number of negated classes containing just a single character
1087        interposed, within parentheses, between a forward reference to a named
1088        subpattern and the definition of the subpattern, compilation crashed with
1089        an internal error, complaining that it could not find the referenced
1090        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1091        [The bug was that it was starting one character too far in when skipping
1092        over the character class, thus treating the ] as data rather than
1093        terminating the class. This meant it could skip too much.]
1094    
1095    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1096        /g option in pcretest when the pattern contains \K, which makes it possible
1097        to have an empty string match not at the start, even when the pattern is
1098        anchored. Updated pcretest and pcredemo to use this option.
1099    
1100    21. If the maximum number of capturing subpatterns in a recursion was greater
1101        than the maximum at the outer level, the higher number was returned, but
1102        with unset values at the outer level. The correct (outer level) value is
1103        now given.
1104    
1105    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1106        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1107        make it do so. The string so far is captured, making this feature
1108        compatible with Perl.
1109    
1110    23. The tests have been re-organized, adding tests 11 and 12, to make it
1111        possible to check the Perl 5.10 features against Perl 5.10.
1112    
1113    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1114        pattern matches a fixed length string. PCRE did not allow this; now it
1115        does. Neither allows recursion.
1116    
1117    25. I finally figured out how to implement a request to provide the minimum
1118        length of subject string that was needed in order to match a given pattern.
1119        (It was back references and recursion that I had previously got hung up
1120        on.) This code has now been added to pcre_study(); it finds a lower bound
1121        to the length of subject needed. It is not necessarily the greatest lower
1122        bound, but using it to avoid searching strings that are too short does give
1123        some useful speed-ups. The value is available to calling programs via
1124        pcre_fullinfo().
1125    
1126    26. While implementing 25, I discovered to my embarrassment that pcretest had
1127        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1128        study optimizations had never been tested with that matching function.
1129        Oops. What is worse, even when it was passed study data, there was a bug in
1130        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1131        were also very few tests of studied patterns with pcre_dfa_exec().
1132    
1133    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1134        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1135        on the other side of the coin, they are no longer allowed to have different
1136        names, because these cannot be distinguished in PCRE, and this has caused
1137        confusion. (This is a difference from Perl.)
1138    
1139    28. When duplicate subpattern names are present (necessarily with different
1140        numbers, as required by 27 above), and a test is made by name in a
1141        conditional pattern, either for a subpattern having been matched, or for
1142        recursion in such a pattern, all the associated numbered subpatterns are
1143        tested, and the overall condition is true if the condition is true for any
1144        one of them. This is the way Perl works, and is also more like the way
1145        testing by number works.
1146    
1147    
1148    Version 7.9 11-Apr-09
1149    ---------------------
1150    
1151    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1152        (pcretest), all targets were linked against these libraries. This included
1153        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1154        libraries. This caused unwanted dependencies to be created. This problem
1155        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1156        pcretest is linked with readline.
1157    
1158    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1159        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1160        moved outside it again, because FALSE and TRUE are already defined in AIX,
1161        but BOOL is not.
1162    
1163    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1164        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1165    
1166    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1167        hyphens) following file names and line numbers when outputting matching
1168        lines. This is not true; no spaces are inserted. I have also clarified the
1169        wording for the --colour (or --color) option.
1170    
1171    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1172        was not coloured; this is different to GNU grep, so I have changed it to be
1173        the same.
1174    
1175    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1176        each matching line was coloured. Now it goes on to look for further matches
1177        of any of the test patterns, which is the same behaviour as GNU grep.
1178    
1179    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1180        doesn't make sense to accept an empty string match in pcregrep, so I have
1181        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1182        seems to be how GNU grep behaves.
1183    
1184    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1185        start or after a newline", because the conditional assertion was not being
1186        correctly handled. The rule now is that both the assertion and what follows
1187        in the first alternative must satisfy the test.
1188    
1189    9.  If auto-callout was enabled in a pattern with a conditional group whose
1190        condition was an assertion, PCRE could crash during matching, both with
1191        pcre_exec() and pcre_dfa_exec().
1192    
1193    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1194        used for matching.
1195    
1196    11. Unicode property support in character classes was not working for
1197        characters (bytes) greater than 127 when not in UTF-8 mode.
1198    
1199    12. Added the -M command line option to pcretest.
1200    
1201    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1202    
1203    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1204    
1205    16. Added comments and documentation about mis-use of no_arg in the C++
1206        wrapper.
1207    
1208    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1209        from Martin Jerabek that uses macro names for all relevant character and
1210        string constants.
1211    
1212    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1213        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1214        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1215        these, but not everybody uses configure.
1216    
1217    19. A conditional group that had only one branch was not being correctly
1218        recognized as an item that could match an empty string. This meant that an
1219        enclosing group might also not be so recognized, causing infinite looping
1220        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1221        with the subject "ab", where knowledge that the repeated group can match
1222        nothing is needed in order to break the loop.
1223    
1224    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1225        exec(), but without supplying a callout function, matching went wrong.
1226    
1227    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1228        leak if the size of the offset vector was greater than 30. When the vector
1229        is smaller, the saved offsets during recursion go onto a local stack
1230        vector, but for larger vectors malloc() is used. It was failing to free
1231        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1232        error, in fact).
1233    
1234    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1235        heapframe that is used only when UTF-8 support is enabled. This caused no
1236        problem, but was untidy.
1237    
1238    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1239        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1240        included within another project.
1241    
1242    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1243        slightly modified by me:
1244    
1245          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1246              not building pcregrep.
1247    
1248          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1249              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1250    
1251    25. Forward references, both numeric and by name, in patterns that made use of
1252        duplicate group numbers, could behave incorrectly or give incorrect errors,
1253        because when scanning forward to find the reference group, PCRE was not
1254        taking into account the duplicate group numbers. A pattern such as
1255        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1256    
1257    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1258        the feature of a custom pointer more persuasive (as requested by a user).
1259    
1260    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1261        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1262        pre-defined.
1263    
1264    28. Added support for (*UTF8) at the start of a pattern.
1265    
1266    29. Arrange for flags added by the "release type" setting in CMake to be shown
1267        in the configuration summary.
1268    
1269    
1270    Version 7.8 05-Sep-08
1271    ---------------------
1272    
1273    1.  Replaced UCP searching code with optimized version as implemented for Ad
1274        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1275        stage table and inline lookup instead of a function, giving speed ups of 2
1276        to 5 times on some simple patterns that I tested. Permission was given to
1277        distribute the MultiStage2.py script that generates the tables (it's not in
1278        the tarball, but is in the Subversion repository).
1279    
1280    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1281        scripts.
1282    
1283    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1284        a group with a zero qualifier. The result of the study could be incorrect,
1285        or the function might crash, depending on the pattern.
1286    
1287    4.  Caseless matching was not working for non-ASCII characters in back
1288        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1289        It now works when Unicode Property Support is available.
1290    
1291    5.  In pcretest, an escape such as \x{de} in the data was always generating
1292        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1293        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1294        truncation.
1295    
1296    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1297    
1298    7.  Added two (int) casts to pcregrep when printing the difference of two
1299        pointers, in case they are 64-bit values.
1300    
1301    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1302        test 2 if it fails.
1303    
1304    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1305        and a #define of that name to empty if it is not externally set. This is to
1306        allow users of MSVC to set it if necessary.
1307    
1308    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1309        the convenience functions in the pcre_get.c source file.
1310    
1311    11. An option change at the start of a pattern that had top-level alternatives
1312        could cause overwriting and/or a crash. This command provoked a crash in
1313        some environments:
1314    
1315          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1316    
1317        This potential security problem was recorded as CVE-2008-2371.
1318    
1319    12. For a pattern where the match had to start at the beginning or immediately
1320        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1321        pcre_dfa_exec() could read past the end of the passed subject if there was
1322        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1323        pcretest so that it places the subject at the end of its malloc-ed buffer.
1324    
1325    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1326        exec() might read past the end of the data buffer in UTF-8 mode.
1327    
1328    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1329        the data contained the byte 0x85 as part of a UTF-8 character within its
1330        first line. This applied both to normal and DFA matching.
1331    
1332    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1333        /^[^d]*?$/8 failed to match "abc".
1334    
1335    16. Added a missing copyright notice to pcrecpp_internal.h.
1336    
1337    17. Make it more clear in the documentation that values returned from
1338        pcre_exec() in ovector are byte offsets, not character counts.
1339    
1340    18. Tidied a few places to stop certain compilers from issuing warnings.
1341    
1342    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1343        supplied by Stefan Weber. I made a further small update for 7.8 because
1344        there is a change of source arrangements: the pcre_searchfuncs.c module is
1345        replaced by pcre_ucd.c.
1346    
1347    
1348    Version 7.7 07-May-08
1349  ---------------------  ---------------------
1350    
1351  1.  Applied Craig's patch to sort out a long long problem: "If we can't convert  1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1352      a string to a long long, pretend we don't even have a long long." This is      a string to a long long, pretend we don't even have a long long." This is
1353      done by checking for the strtoq, strtoll, and _strtoi64 functions.      done by checking for the strtoq, strtoll, and _strtoi64 functions.
1354    
1355  2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with  2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1356      pre-7.6 versions, which defined a global no_arg variable instead of putting      pre-7.6 versions, which defined a global no_arg variable instead of putting
1357      it in the RE class. (See also #8 below.)      it in the RE class. (See also #8 below.)
1358    
1359  3.  Remove a line of dead code, identified by coverity and reported by Nuno  3.  Remove a line of dead code, identified by coverity and reported by Nuno
1360      Lopes.      Lopes.
1361    
1362  4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:  4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1363    
1364      (1) The include/exclude patterns were being applied to the whole pathnames      (1) The include/exclude patterns were being applied to the whole pathnames
1365          of files, instead of just to the final components.          of files, instead of just to the final components.
1366    
1367      (2) If there was more than one level of directory, the subdirectories were      (2) If there was more than one level of directory, the subdirectories were
1368          skipped unless they satisfied the include/exclude conditions. This is          skipped unless they satisfied the include/exclude conditions. This is
1369          inconsistent with GNU grep (and could even be seen as contrary to the          inconsistent with GNU grep (and could even be seen as contrary to the
1370          pcregrep specification - which I improved to make it absolutely clear).          pcregrep specification - which I improved to make it absolutely clear).
1371          The action now is always to scan all levels of directory, and just          The action now is always to scan all levels of directory, and just
1372          apply the include/exclude patterns to regular files.          apply the include/exclude patterns to regular files.
1373    
1374  5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used  5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1375      --exclude_dir in the tests to avoid scanning .svn directories.      --exclude_dir in the tests to avoid scanning .svn directories.
1376    
1377  6.  Applied Craig's patch to the QuoteMeta function so that it escapes the  6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1378      NUL character as backslash + 0 rather than backslash + NUL, because PCRE      NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1379      doesn't support NULs in patterns.      doesn't support NULs in patterns.
1380    
1381  7.  Added some missing "const"s to declarations of static tables in  7.  Added some missing "const"s to declarations of static tables in
1382      pcre_compile.c and pcre_dfa_exec.c.      pcre_compile.c and pcre_dfa_exec.c.
1383    
1384  8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was  8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1385      caused by fix #2  above. (Subsequently also a second patch to fix the      caused by fix #2  above. (Subsequently also a second patch to fix the
1386      first patch. And a third patch - this was a messy problem.)      first patch. And a third patch - this was a messy problem.)
1387    
1388  9.  Applied Craig's patch to remove the use of push_back().  9.  Applied Craig's patch to remove the use of push_back().
1389    
1390  10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX  10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1391      matching function regexec().      matching function regexec().
1392    
1393    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1394        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1395        references. PCRE supports relative numbers with this syntax (I don't think
1396        Oniguruma does).
1397    
1398    12. Previously, a group with a zero repeat such as (...){0} was completely
1399        omitted from the compiled regex. However, this means that if the group
1400        was called as a subroutine from elsewhere in the pattern, things went wrong
1401        (an internal error was given). Such groups are now left in the compiled
1402        pattern, with a new opcode that causes them to be skipped at execution
1403        time.
1404    
1405    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1406        to the way PCRE behaves:
1407    
1408        (a) A lone ] character is dis-allowed (Perl treats it as data).
1409    
1410        (b) A back reference to an unmatched subpattern matches an empty string
1411            (Perl fails the current match path).
1412    
1413        (c) A data ] in a character class must be notated as \] because if the
1414            first data character in a class is ], it defines an empty class. (In
1415            Perl it is not possible to have an empty class.) The empty class []
1416            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1417            The negative empty class [^] matches any one character, independently
1418            of the DOTALL setting.
1419    
1420    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1421        non-existent subpattern following a character class starting with ']' and
1422        containing () gave an internal compiling error instead of "reference to
1423        non-existent subpattern". Fortunately, when the pattern did exist, the
1424        compiled code was correct. (When scanning forwards to check for the
1425        existencd of the subpattern, it was treating the data ']' as terminating
1426        the class, so got the count wrong. When actually compiling, the reference
1427        was subsequently set up correctly.)
1428    
1429    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1430        it was being rejected as not supported by pcre_dfa_exec(), even though
1431        other assertions are supported. I have made pcre_dfa_exec() support
1432        (*FAIL).
1433    
1434    16. The implementation of 13c above involved the invention of a new opcode,
1435        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1436        cannot be changed at match time, I realized I could make a small
1437        improvement to matching performance by compiling OP_ALLANY instead of
1438        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1439        on the OP_ANY path.
1440    
1441    17. Compiling pcretest on Windows with readline support failed without the
1442        following two fixes: (1) Make the unistd.h include conditional on
1443        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1444    
1445    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1446        ncurses library to be included for pcretest when ReadLine support is
1447        requested, but also to allow for it to be overridden. This patch came from
1448        Daniel Bergström.
1449    
1450    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1451        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1452        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1453        spotting this.
1454    
1455    
1456  Version 7.6 28-Jan-08  Version 7.6 28-Jan-08
1457  ---------------------  ---------------------

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