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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.0 02 Jul-08  Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    
16    Version 8.30 04-February-2012
17    -----------------------------
18    
19    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
20        name is defined in ctype.h.
21    
22    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
23        only in quite long subpatterns.
24    
25    3.  Removed the function pcre_info(), which has been obsolete and deprecated
26        since it was replaced by pcre_fullinfo() in February 2000.
27    
28    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
29        match a (*MARK), and the match failed at the start of the subject, a
30        reference to memory before the start of the subject could occur. This bug
31        was introduced by fix 17 of release 8.21.
32    
33    5.  A reference to an unset group with zero minimum repetition was giving
34        totally wrong answers (in non-JavaScript-compatibility mode). For example,
35        /(another)?(\1?)test/ matched against "hello world test". This bug was
36        introduced in release 8.13.
37    
38    6.  Add support for 16-bit character strings (a large amount of work involving
39        many changes and refactorings).
40    
41    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
42        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
43        from a file.
44    
45    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
46        rounding is not applied in this particular case).
47    
48    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
49        if they appear, or are escaped, in patterns.
50    
51    10. Get rid of a number of -Wunused-but-set-variable warnings.
52    
53    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
54        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
55        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
56        also returns the mark "x". This bug applied to capturing parentheses,
57        non-capturing parentheses, and atomic parentheses. It also applied to some
58        assertions.
59    
60    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
61        information out of configure.ac instead of relying on pcre.h.generic, which
62        is not stored in the repository.
63    
64    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
65        -lreadline.
66    
67    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
68    
69    15. Applied Graycode's patch to put the top-level frame on the stack rather
70        than the heap when not using the stack for recursion. This gives a
71        performance improvement in many cases when recursion is not deep.
72    
73    16. Experimental code added to "pcretest -C" to output the stack frame size.
74    
75    
76    Version 8.21 12-Dec-2011
77    ------------------------
78    
79    1.  Updating the JIT compiler.
80    
81    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
82        are added as well.
83    
84    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
85        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
86        calling _pcre_jit_exec. Some extra comments are added.
87    
88    4.  (*MARK) settings inside atomic groups that do not contain any capturing
89        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
90        was introduced by change 18 for 8.20.
91    
92    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
93        ECMA-262 standard.
94    
95    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
96        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
97        This bug was probably introduced by change 9 of 8.13.
98    
99    7.  While fixing 6 above, I noticed that a number of other items were being
100        incorrectly rejected as "not fixed length". This arose partly because newer
101        opcodes had not been added to the fixed-length checking code. I have (a)
102        corrected the bug and added tests for these items, and (b) arranged for an
103        error to occur if an unknown opcode is encountered while checking for fixed
104        length instead of just assuming "not fixed length". The items that were
105        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
106        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
107        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
108    
109    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
110        being incorrectly compiled and would have given unpredicatble results.
111    
112    9.  A possessively repeated subpattern with minimum repeat count greater than
113        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
114        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
115        the first (A) could occur when it should not.
116    
117    10. Add a cast and remove a redundant test from the code.
118    
119    11. JIT should use pcre_malloc/pcre_free for allocation.
120    
121    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
122        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
123        is anything other than /usr, -L is still shown).
124    
125    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
126    
127    14. Perl does not support \N without a following name in a [] class; PCRE now
128        also gives an error.
129    
130    15. If a forward reference was repeated with an upper limit of around 2000,
131        it caused the error "internal error: overran compiling workspace". The
132        maximum number of forward references (including repeats) was limited by the
133        internal workspace, and dependent on the LINK_SIZE. The code has been
134        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
135        the default depends on LINK_SIZE. There is a new upper limit (for safety)
136        of around 200,000 forward references. While doing this, I also speeded up
137        the filling in of repeated forward references.
138    
139    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
140        incorrectly expecting the subject to contain another "a" after the start.
141    
142    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
143        in the match, the SKIP should be ignored. This was not happening; instead
144        the SKIP was being treated as NOMATCH. For patterns such as
145        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
146        tested.
147    
148    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
149        now much more compatible with Perl, in particular in cases where the result
150        is a non-match for a non-anchored pattern. For example, if
151        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
152        "m", where previously it did not return a name. A side effect of this
153        change is that for partial matches, the last encountered mark name is
154        returned, as for non matches. A number of tests that were previously not
155        Perl-compatible have been moved into the Perl-compatible test files. The
156        refactoring has had the pleasing side effect of removing one argument from
157        the match() function, thus reducing its stack requirements.
158    
159    19. If the /S+ option was used in pcretest to study a pattern using JIT,
160        subsequent uses of /S (without +) incorrectly behaved like /S+.
161    
162    21. Retrieve executable code size support for the JIT compiler and fixing
163        some warnings.
164    
165    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
166        not work when the shorter character appeared right at the end of the
167        subject string.
168    
169    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
170        systems.
171    
172    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
173        output it when the /M option is used in pcretest.
174    
175    25. The CheckMan script was not being included in the distribution. Also, added
176        an explicit "perl" to run Perl scripts from the PrepareRelease script
177        because this is reportedly needed in Windows.
178    
179    26. If study data was being save in a file and studying had not found a set of
180        "starts with" bytes for the pattern, the data written to the file (though
181        never used) was taken from uninitialized memory and so caused valgrind to
182        complain.
183    
184    27. Updated RunTest.bat as provided by Sheri Pierce.
185    
186    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
187    
188    29. Computation of memory usage for the table of capturing group names was
189        giving an unnecessarily large value.
190    
191    
192    Version 8.20 21-Oct-2011
193    ------------------------
194    
195    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
196        a POSIX class. After further experiments with Perl, which convinced me that
197        Perl has bugs and confusions, a closing square bracket is no longer allowed
198        in a POSIX name. This bug also affected patterns with classes that started
199        with full stops.
200    
201    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
202        captured substring, but while checking the failing first alternative,
203        substring 1 is temporarily captured. If the output vector supplied to
204        pcre_exec() was not big enough for this capture, the yield of the function
205        was still zero ("insufficient space for captured substrings"). This cannot
206        be totally fixed without adding another stack variable, which seems a lot
207        of expense for a edge case. However, I have improved the situation in cases
208        such as /(a)(b)x|abc/ matched against "abc", where the return code
209        indicates that fewer than the maximum number of slots in the ovector have
210        been set.
211    
212    3.  Related to (2) above: when there are more back references in a pattern than
213        slots in the output vector, pcre_exec() uses temporary memory during
214        matching, and copies in the captures as far as possible afterwards. It was
215        using the entire output vector, but this conflicts with the specification
216        that only 2/3 is used for passing back captured substrings. Now it uses
217        only the first 2/3, for compatibility. This is, of course, another edge
218        case.
219    
220    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
221        main code base, and can be used by building with --enable-jit. When this is
222        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
223        runtime --no-jit option is given.
224    
225    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
226        ovector, the return from the function was zero, implying that there were
227        other matches that did not fit. The correct "exactly full" value is now
228        returned.
229    
230    6.  If a subpattern that was called recursively or as a subroutine contained
231        (*PRUNE) or any other control that caused it to give a non-standard return,
232        invalid errors such as "Error -26 (nested recursion at the same subject
233        position)" or even infinite loops could occur.
234    
235    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
236        computing the minimum length on reaching *ACCEPT, and so ended up with the
237        wrong value of 1 rather than 0. Further investigation indicates that
238        computing a minimum subject length in the presence of *ACCEPT is difficult
239        (think back references, subroutine calls), and so I have changed the code
240        so that no minimum is registered for a pattern that contains *ACCEPT.
241    
242    8.  If (*THEN) was present in the first (true) branch of a conditional group,
243        it was not handled as intended. [But see 16 below.]
244    
245    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
246        Sheri Pierce.
247    
248    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
249        the first byte in a match must be "a".
250    
251    11. Change 17 for 8.13 increased the recursion depth for patterns like
252        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
253        pattern contains any instances of (*THEN). If it does not, the old
254        optimizations are restored. It would be nice to do this on a per-group
255        basis, but at the moment that is not feasible.
256    
257    12. In some environments, the output of pcretest -C is CRLF terminated. This
258        broke RunTest's code that checks for the link size. A single white space
259        character after the value is now allowed for.
260    
261    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
262        For "fr", it uses the Windows-specific input and output files.
263    
264    14. If (*THEN) appeared in a group that was called recursively or as a
265        subroutine, it did not work as intended. [But see next item.]
266    
267    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
268        pattern fragments (but not containing any | characters). If A and B are
269        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
270        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
271        D. In other words, Perl considers parentheses that do not contain any |
272        characters to be part of a surrounding alternative, whereas PCRE was
273        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
274        differently. PCRE now behaves in the same way as Perl, except in the case
275        of subroutine/recursion calls such as (?1) which have in any case always
276        been different (but PCRE had them first :-).
277    
278    16. Related to 15 above: Perl does not treat the | in a conditional group as
279        creating alternatives. Such a group is treated in the same way as an
280        ordinary group without any | characters when processing (*THEN). PCRE has
281        been changed to match Perl's behaviour.
282    
283    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
284        RunGrepTest script failed.
285    
286    18. Change 22 for version 13 caused atomic groups to use more stack. This is
287        inevitable for groups that contain captures, but it can lead to a lot of
288        stack use in large patterns. The old behaviour has been restored for atomic
289        groups that do not contain any capturing parentheses.
290    
291    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
292        suppress the check for a minimum subject length at run time. (If it was
293        given to pcre_exec() or pcre_dfa_exec() it did work.)
294    
295    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
296        fail to work when decoding hex characters in data strings in EBCDIC
297        environments.
298    
299    21. It appears that in at least one Mac OS environment, the isxdigit() function
300        is implemented as a macro that evaluates to its argument more than once,
301        contravening the C 90 Standard (I haven't checked a later standard). There
302        was an instance in pcretest which caused it to go wrong when processing
303        \x{...} escapes in subject strings. The has been rewritten to avoid using
304        things like p++ in the argument of isxdigit().
305    
306    
307    Version 8.13 16-Aug-2011
308    ------------------------
309    
310    1.  The Unicode data tables have been updated to Unicode 6.0.0.
311    
312    2.  Two minor typos in pcre_internal.h have been fixed.
313    
314    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
315        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
316        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
317    
318    4.  There were a number of related bugs in the code for matching backrefences
319        caselessly in UTF-8 mode when codes for the characters concerned were
320        different numbers of bytes. For example, U+023A and U+2C65 are an upper
321        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
322        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
323        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
324        2-byte code at the end of the subject (it thought there wasn't enough data
325        left).
326    
327    5.  Comprehensive information about what went wrong is now returned by
328        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
329        as the output vector has at least 2 elements. The offset of the start of
330        the failing character and a reason code are placed in the vector.
331    
332    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
333        now returned is for the first byte of the failing character, instead of the
334        last byte inspected. This is an incompatible change, but I hope it is small
335        enough not to be a problem. It makes the returned offset consistent with
336        pcre_exec() and pcre_dfa_exec().
337    
338    7.  pcretest now gives a text phrase as well as the error number when
339        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
340        failure, the offset and reason code are output.
341    
342    8.  When \R was used with a maximizing quantifier it failed to skip backwards
343        over a \r\n pair if the subsequent match failed. Instead, it just skipped
344        back over a single character (\n). This seems wrong (because it treated the
345        two characters as a single entity when going forwards), conflicts with the
346        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
347        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
348        has been changed.
349    
350    9.  Some internal refactoring has changed the processing so that the handling
351        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
352        time (the PCRE_DOTALL option was changed this way some time ago: version
353        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
354        which was always a bit of a fudge. It also means that there is one less
355        argument for the match() function, which reduces its stack requirements
356        slightly. This change also fixes an incompatibility with Perl: the pattern
357        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
358    
359    10. More internal refactoring has drastically reduced the number of recursive
360        calls to match() for possessively repeated groups such as (abc)++ when
361        using pcre_exec().
362    
363    11. While implementing 10, a number of bugs in the handling of groups were
364        discovered and fixed:
365    
366        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
367        (a|)*(?1) gave a compile-time internal error.
368        ((a|)+)+  did not notice that the outer group could match an empty string.
369        (^a|^)+   was not marked as anchored.
370        (.*a|.*)+ was not marked as matching at start or after a newline.
371    
372    12. Yet more internal refactoring has removed another argument from the match()
373        function. Special calls to this function are now indicated by setting a
374        value in a variable in the "match data" data block.
375    
376    13. Be more explicit in pcre_study() instead of relying on "default" for
377        opcodes that mean there is no starting character; this means that when new
378        ones are added and accidentally left out of pcre_study(), testing should
379        pick them up.
380    
381    14. The -s option of pcretest has been documented for ages as being an old
382        synonym of -m (show memory usage). I have changed it to mean "force study
383        for every regex", that is, assume /S for every regex. This is similar to -i
384        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
385        using it. It makes it easier to run collections of tests with and without
386        study enabled, and thereby test pcre_study() more easily. All the standard
387        tests are now run with and without -s (but some patterns can be marked as
388        "never study" - see 20 below).
389    
390    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
391        restoration of the capturing data to the outer values was not happening
392        correctly.
393    
394    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
395        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
396        pattern had matched an empty string, and so incorrectly returned a no
397        match.
398    
399    17. There was optimizing code for the last branch of non-capturing parentheses,
400        and also for the obeyed branch of a conditional subexpression, which used
401        tail recursion to cut down on stack usage. Unfortunately, now that there is
402        the possibility of (*THEN) occurring in these branches, tail recursion is
403        no longer possible because the return has to be checked for (*THEN). These
404        two optimizations have therefore been removed. [But see 8.20/11 above.]
405    
406    18. If a pattern containing \R was studied, it was assumed that \R always
407        matched two bytes, thus causing the minimum subject length to be
408        incorrectly computed because \R can also match just one byte.
409    
410    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
411        was incorrectly computed.
412    
413    20. If /S is present twice on a test pattern in pcretest input, it now
414        *disables* studying, thereby overriding the use of -s on the command line
415        (see 14 above). This is necessary for one or two tests to keep the output
416        identical in both cases.
417    
418    21. When (*ACCEPT) was used in an assertion that matched an empty string and
419        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
420    
421    22. When an atomic group that contained a capturing parenthesis was
422        successfully matched, but the branch in which it appeared failed, the
423        capturing was not being forgotten if a higher numbered group was later
424        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
425        group 1 to "a", when in fact it should be unset. This applied to multi-
426        branched capturing and non-capturing groups, repeated or not, and also to
427        positive assertions (capturing in negative assertions does not happen
428        in PCRE) and also to nested atomic groups.
429    
430    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
431        subject after a captured substring, to make it easier to tell which of a
432        number of identical substrings has been captured.
433    
434    24. The way atomic groups are processed by pcre_exec() has been changed so that
435        if they are repeated, backtracking one repetition now resets captured
436        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
437        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
438        "aaa". Previously, it would have been "a". As part of this code
439        refactoring, the way recursive calls are handled has also been changed.
440    
441    25. If an assertion condition captured any substrings, they were not passed
442        back unless some other capturing happened later. For example, if
443        (?(?=(a))a) was matched against "a", no capturing was returned.
444    
445    26. When studying a pattern that contained subroutine calls or assertions,
446        the code for finding the minimum length of a possible match was handling
447        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
448        group 1 called group 2 while simultaneously a separate group 2 called group
449        1). A stack overflow occurred in this case. I have fixed this by limiting
450        the recursion depth to 10.
451    
452    27. Updated RunTest.bat in the distribution to the version supplied by Tom
453        Fortmann. This supports explicit test numbers on the command line, and has
454        argument validation and error reporting.
455    
456    28. An instance of \X with an unlimited repeat could fail if at any point the
457        first character it looked at was a mark character.
458    
459    29. Some minor code refactoring concerning Unicode properties and scripts
460        should reduce the stack requirement of match() slightly.
461    
462    30. Added the '=' option to pcretest to check the setting of unused capturing
463        slots at the end of the pattern, which are documented as being -1, but are
464        not included in the return count.
465    
466    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
467        compiled something random. Now it gives a compile-time error (as does
468        Perl).
469    
470    32. A *MARK encountered during the processing of a positive assertion is now
471        recorded and passed back (compatible with Perl).
472    
473    33. If --only-matching or --colour was set on a pcregrep call whose pattern
474        had alternative anchored branches, the search for a second match in a line
475        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
476        matched the line "0102" twice. The same bug affected patterns that started
477        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
478        twice.
479    
480    34. Previously, PCRE did not allow quantification of assertions. However, Perl
481        does, and because of capturing effects, quantifying parenthesized
482        assertions may at times be useful. Quantifiers are now allowed for
483        parenthesized assertions.
484    
485    35. A minor code tidy in pcre_compile() when checking options for \R usage.
486    
487    36. \g was being checked for fancy things in a character class, when it should
488        just be a literal "g".
489    
490    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
491        appearance of a nested POSIX class supersedes an apparent external class.
492        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
493        unescaped square brackets may also appear as part of class names. For
494        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
495        more like Perl. (But see 8.20/1 above.)
496    
497    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
498        was because it thought it was \N{name}, which is not supported).
499    
500    39. Add minix to OS list not supporting the -S option in pcretest.
501    
502    40. PCRE tries to detect cases of infinite recursion at compile time, but it
503        cannot analyze patterns in sufficient detail to catch mutual recursions
504        such as ((?1))((?2)). There is now a runtime test that gives an error if a
505        subgroup is called recursively as a subpattern for a second time at the
506        same position in the subject string. In previous releases this might have
507        been caught by the recursion limit, or it might have run out of stack.
508    
509    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
510        happen only once. PCRE was, however incorrectly giving a compile time error
511        "recursive call could loop indefinitely" because it cannot analyze the
512        pattern in sufficient detail. The compile time test no longer happens when
513        PCRE is compiling a conditional subpattern, but actual runaway loops are
514        now caught at runtime (see 40 above).
515    
516    42. It seems that Perl allows any characters other than a closing parenthesis
517        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
518        has been changed to be the same.
519    
520    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
521        as not to get warnings when autogen.sh is called. Also changed
522        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
523    
524    44. To help people who use pcregrep to scan files containing exceedingly long
525        lines, the following changes have been made:
526    
527        (a) The default value of the buffer size parameter has been increased from
528            8K to 20K. (The actual buffer used is three times this size.)
529    
530        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
531            PCRE is built.
532    
533        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
534            to be set at run time.
535    
536        (d) Numerical values in pcregrep options can be followed by K or M, for
537            example --buffer-size=50K.
538    
539        (e) If a line being scanned overflows pcregrep's buffer, an error is now
540            given and the return code is set to 2.
541    
542    45. Add a pointer to the latest mark to the callout data block.
543    
544    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
545        partial match of an empty string instead of no match. This was specific to
546        the use of ".".
547    
548    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
549        complete match instead of a partial match. This bug was dependent on both
550        the PCRE_UTF8 and PCRE_DOTALL options being set.
551    
552    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
553        starting byte set, because \b was not being ignored.
554    
555    
556    Version 8.12 15-Jan-2011
557    ------------------------
558    
559    1.  Fixed some typos in the markup of the man pages, and wrote a script that
560        checks for such things as part of the documentation building process.
561    
562    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
563        --match-limit and --recursion-limit options (added for 8.11). In
564        particular, this made one of the standard tests fail. (The integer value
565        went into the wrong half of a long int.)
566    
567    3.  If the --colour option was given to pcregrep with -v (invert match), it
568        did strange things, either producing crazy output, or crashing. It should,
569        of course, ignore a request for colour when reporting lines that do not
570        match.
571    
572    4.  Another pcregrep bug caused similar problems if --colour was specified with
573        -M (multiline) and the pattern match finished with a line ending.
574    
575    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
576        matched in multiline mode, the following line was shown as part of the
577        match. This seems wrong, so I have changed it.
578    
579    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
580        the check for further matches in the same line (so they could be coloured)
581        to overrun the end of the current line. If another match was found, it was
582        incorrectly shown (and then shown again when found in the next line).
583    
584    7.  If pcregrep was compiled under Windows, there was a reference to the
585        function pcregrep_exit() before it was defined. I am assuming this was
586        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
587        reported by a user. I've moved the definition above the reference.
588    
589    
590    Version 8.11 10-Dec-2010
591    ------------------------
592    
593    1.  (*THEN) was not working properly if there were untried alternatives prior
594        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
595        backtracked to try for "b" instead of moving to the next alternative branch
596        at the same level (in this case, to look for "c"). The Perl documentation
597        is clear that when (*THEN) is backtracked onto, it goes to the "next
598        alternative in the innermost enclosing group".
599    
600    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
601        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
602        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
603        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
604        (*THEN).
605    
606    3.  If \s appeared in a character class, it removed the VT character from
607        the class, even if it had been included by some previous item, for example
608        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
609        of \s, but is part of the POSIX "space" class.)
610    
611    4.  A partial match never returns an empty string (because you can always
612        match an empty string at the end of the subject); however the checking for
613        an empty string was starting at the "start of match" point. This has been
614        changed to the "earliest inspected character" point, because the returned
615        data for a partial match starts at this character. This means that, for
616        example, /(?<=abc)def/ gives a partial match for the subject "abc"
617        (previously it gave "no match").
618    
619    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
620        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
621        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
622        has an implication that the given string is incomplete (because a partial
623        match is preferred over a full match). For this reason, these items now
624        give a partial match in this situation. [Aside: previously, the one case
625        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
626        match rather than a full match, which was wrong by the old rules, but is
627        now correct.]
628    
629    6.  There was a bug in the handling of #-introduced comments, recognized when
630        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
631        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
632        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
633        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
634        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
635        places in pcre_compile().
636    
637    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
638        comments when looking ahead for named forward references to subpatterns,
639        the only newline sequence it recognized was NL. It now handles newlines
640        according to the set newline convention.
641    
642    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
643        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
644        cater for a lack of strerror(). These oversights have been fixed.
645    
646    9.  Added --match-limit and --recursion-limit to pcregrep.
647    
648    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
649    
650    11. When the -o option was used, pcregrep was setting a return code of 1, even
651        when matches were found, and --line-buffered was not being honoured.
652    
653    12. Added an optional parentheses number to the -o and --only-matching options
654        of pcregrep.
655    
656    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
657        can match an empty string. The code to do it in pcretest and pcredemo
658        needed fixing:
659    
660        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
661            only one byte after an empty string match just before CRLF (this case
662            just got forgotten; "any" and "anycrlf" were OK).
663    
664        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
665            mode when an empty string match preceded an ASCII character followed by
666            a non-ASCII character. (The code for advancing by one character rather
667            than one byte was nonsense.)
668    
669        (c) The pcredemo.c sample program did not have any code at all to handle
670            the cases when CRLF is a valid newline sequence.
671    
672    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
673        as a starting offset was within the subject string. There is now a new
674        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
675        negative or greater than the length of the string. In order to test this,
676        pcretest is extended to allow the setting of negative starting offsets.
677    
678    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
679        starting offset points to the beginning of a UTF-8 character was
680        unnecessarily clumsy. I tidied it up.
681    
682    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
683        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
684    
685    17. Nobody had reported that the --include_dir option, which was added in
686        release 7.7 should have been called --include-dir (hyphen, not underscore)
687        for compatibility with GNU grep. I have changed it to --include-dir, but
688        left --include_dir as an undocumented synonym, and the same for
689        --exclude-dir, though that is not available in GNU grep, at least as of
690        release 2.5.4.
691    
692    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
693        characters from a string of bytes) have been redefined so as not to use
694        loops, in order to improve performance in some environments. At the same
695        time, I abstracted some of the common code into auxiliary macros to save
696        repetition (this should not affect the compiled code).
697    
698    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
699        compile-time error is now given if \c is not followed by an ASCII
700        character, that is, a byte less than 128. (In EBCDIC mode, the code is
701        different, and any byte value is allowed.)
702    
703    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
704        START_OPTIMIZE option, which is now allowed at compile time - but just
705        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
706        to pcregrep and other applications that have no direct access to PCRE
707        options. The new /Y option in pcretest sets this option when calling
708        pcre_compile().
709    
710    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
711        back references. Groups containing recursive back references were forced to
712        be atomic by that change, but in the case of named groups, the amount of
713        memory required was incorrectly computed, leading to "Failed: internal
714        error: code overflow". This has been fixed.
715    
716    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
717        pcretest.c, to avoid build problems in some Borland environments.
718    
719    
720    Version 8.10 25-Jun-2010
721    ------------------------
722    
723    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
724        THEN.
725    
726    2.  (*ACCEPT) was not working when inside an atomic group.
727    
728    3.  Inside a character class, \B is treated as a literal by default, but
729        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
730        causes the error). The code is unchanged, but I tidied the documentation.
731    
732    4.  Inside a character class, PCRE always treated \R and \X as literals,
733        whereas Perl faults them if its -w option is set. I have changed PCRE so
734        that it faults them when PCRE_EXTRA is set.
735    
736    5.  Added support for \N, which always matches any character other than
737        newline. (It is the same as "." when PCRE_DOTALL is not set.)
738    
739    6.  When compiling pcregrep with newer versions of gcc which may have
740        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
741        declared with attribute warn_unused_result" were given. Just casting the
742        result to (void) does not stop the warnings; a more elaborate fudge is
743        needed. I've used a macro to implement this.
744    
745    7.  Minor change to pcretest.c to avoid a compiler warning.
746    
747    8.  Added four artifical Unicode properties to help with an option to make
748        \s etc use properties (see next item). The new properties are: Xan
749        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
750    
751    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
752        use Unicode properties. (*UCP) at the start of a pattern can be used to set
753        this option. Modified pcretest to add /W to test this facility. Added
754        REG_UCP to make it available via the POSIX interface.
755    
756    10. Added --line-buffered to pcregrep.
757    
758    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
759        studied, and the match started with a letter with a code point greater than
760        127 whose first byte was different to the first byte of the other case of
761        the letter, the other case of this starting letter was not recognized
762        (#976).
763    
764    12. If a pattern that was studied started with a repeated Unicode property
765        test, for example, \p{Nd}+, there was the theoretical possibility of
766        setting up an incorrect bitmap of starting bytes, but fortunately it could
767        not have actually happened in practice until change 8 above was made (it
768        added property types that matched character-matching opcodes).
769    
770    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
771        possible starting bytes for non-anchored patterns.
772    
773    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
774        \R, and also a number of cases that involve Unicode properties, both
775        explicit and implicit when PCRE_UCP is set.
776    
777    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
778        input, it could crash or give wrong results if characters with values
779        greater than 0xc0 were present in the subject string. (Detail: it assumed
780        UTF-8 input when processing these items.)
781    
782    16. Added a lot of (int) casts to avoid compiler warnings in systems where
783        size_t is 64-bit (#991).
784    
785    17. Added a check for running out of memory when PCRE is compiled with
786        --disable-stack-for-recursion (#990).
787    
788    18. If the last data line in a file for pcretest does not have a newline on
789        the end, a newline was missing in the output.
790    
791    19. The default pcre_chartables.c file recognizes only ASCII characters (values
792        less than 128) in its various bitmaps. However, there is a facility for
793        generating tables according to the current locale when PCRE is compiled. It
794        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
795        characters, are recognized by isspace() and therefore were getting set in
796        these tables, and indeed these tables seem to approximate to ISO 8859. This
797        caused a problem in UTF-8 mode when pcre_study() was used to create a list
798        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
799        which of course cannot start UTF-8 characters. I have changed the code so
800        that only real ASCII characters (less than 128) and the correct starting
801        bytes for UTF-8 encodings are set for characters greater than 127 when in
802        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
803        altogether.)
804    
805    20. Added the /T option to pcretest so as to be able to run tests with non-
806        standard character tables, thus making it possible to include the tests
807        used for 19 above in the standard set of tests.
808    
809    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
810        reference to a subpattern the other side of a comment that contains an
811        opening parenthesis caused either an internal compiling error, or a
812        reference to the wrong subpattern.
813    
814    
815    Version 8.02 19-Mar-2010
816    ------------------------
817    
818    1.  The Unicode data tables have been updated to Unicode 5.2.0.
819    
820    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
821        configured.
822    
823    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
824        original author of that file, following a query about its status.
825    
826    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
827        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
828    
829    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
830        quantifier applied to a forward-referencing subroutine call, could compile
831        incorrect code or give the error "internal error: previously-checked
832        referenced subpattern not found".
833    
834    6.  Both MS Visual Studio and Symbian OS have problems with initializing
835        variables to point to external functions. For these systems, therefore,
836        pcre_malloc etc. are now initialized to local functions that call the
837        relevant global functions.
838    
839    7.  There were two entries missing in the vectors called coptable and poptable
840        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
841        I've fixed the data, and added a kludgy way of testing at compile time that
842        the lengths are correct (equal to the number of opcodes).
843    
844    8.  Following on from 7, I added a similar kludge to check the length of the
845        eint vector in pcreposix.c.
846    
847    9.  Error texts for pcre_compile() are held as one long string to avoid too
848        much relocation at load time. To find a text, the string is searched,
849        counting zeros. There was no check for running off the end of the string,
850        which could happen if a new error number was added without updating the
851        string.
852    
853    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
854    
855    11. \K was not working if it appeared in an atomic group or in a group that
856        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
857        \K is "not well defined" if used in an assertion. PCRE now accepts it if
858        the assertion is positive, but not if it is negative.
859    
860    12. Change 11 fortuitously reduced the size of the stack frame used in the
861        "match()" function of pcre_exec.c by one pointer. Forthcoming
862        implementation of support for (*MARK) will need an extra pointer on the
863        stack; I have reserved it now, so that the stack frame size does not
864        decrease.
865    
866    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
867        item in branch that calls a recursion is a subroutine call - as in the
868        second branch in the above example - was incorrectly given the compile-
869        time error "recursive call could loop indefinitely" because pcre_compile()
870        was not correctly checking the subroutine for matching a non-empty string.
871    
872    14. The checks for overrunning compiling workspace could trigger after an
873        overrun had occurred. This is a "should never occur" error, but it can be
874        triggered by pathological patterns such as hundreds of nested parentheses.
875        The checks now trigger 100 bytes before the end of the workspace.
876    
877    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
878    
879    
880    Version 8.01 19-Jan-2010
881    ------------------------
882    
883    1.  If a pattern contained a conditional subpattern with only one branch (in
884        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
885        computed the wrong minimum data length (which is of course zero for such
886        subpatterns). This could cause incorrect "no match" results.
887    
888    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
889        the pattern is reset in the first branch, pcre_compile() failed with
890        "internal error: code overflow at offset...". This happened only when
891        the reset was to the original external option setting. (An optimization
892        abstracts leading options settings into an external setting, which was the
893        cause of this.)
894    
895    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
896        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
897        assertion pattern did not match (meaning that the assertion was true), it
898        was incorrectly treated as false if the SKIP had been reached during the
899        matching. This also applied to assertions used as conditions.
900    
901    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
902        assertion subpattern, including such a pattern used as a condition,
903        unpredictable results occurred, instead of the error return
904        PCRE_ERROR_DFA_UITEM.
905    
906    5.  The C++ GlobalReplace function was not working like Perl for the special
907        situation when an empty string is matched. It now does the fancy magic
908        stuff that is necessary.
909    
910    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
911        removed. (These were left over from very, very early versions of PCRE.)
912    
913    7.  Some cosmetic changes to the code to make life easier when compiling it
914        as part of something else:
915    
916        (a) Change DEBUG to PCRE_DEBUG.
917    
918        (b) In pcre_compile(), rename the member of the "branch_chain" structure
919            called "current" as "current_branch", to prevent a collision with the
920            Linux macro when compiled as a kernel module.
921    
922        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
923            prevent a collision with the Linux macro when compiled as a kernel
924            module.
925    
926    8.  In pcre_compile() there are some checks for integer overflows that used to
927        cast potentially large values to (double). This has been changed to that
928        when building, a check for int64_t is made, and if it is found, it is used
929        instead, thus avoiding the use of floating point arithmetic. (There is no
930        other use of FP in PCRE.) If int64_t is not found, the fallback is to
931        double.
932    
933    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
934        2005 (difference between two addresses compared to an unsigned value).
935    
936    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
937        custom one, because of the following reported problem in Windows:
938    
939          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
940              under Win32.
941          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
942              therefore missing the function definition.
943          - The compiler thus generates a "C" signature for the test function.
944          - The linker fails to find the "C" function.
945          - PCRE fails to configure if asked to do so against libbz2.
946    
947    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
948        messages were output:
949    
950          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
951          rerunning libtoolize, to keep the correct libtool macros in-tree.
952          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
953    
954        I have done both of these things.
955    
956    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
957        most of the time, it *can* run out if it is given a pattern that contains a
958        runaway infinite recursion. I updated the discussion in the pcrestack man
959        page.
960    
961    13. Now that we have gone to the x.xx style of version numbers, the minor
962        version may start with zero. Using 08 or 09 is a bad idea because users
963        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
964        interpreted as invalid octal numbers. I've updated the previous comment in
965        configure.ac, and also added a check that gives an error if 08 or 09 are
966        used.
967    
968    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
969        causing partial matching to fail when the end of the subject matched \W
970        in a UTF-8 pattern where \W was quantified with a minimum of 3.
971    
972    15. There were some discrepancies between the declarations in pcre_internal.h
973        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
974        their definitions. The declarations used "const uschar *" and the
975        definitions used USPTR. Even though USPTR is normally defined as "const
976        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
977        reported that: "This difference in casting confuses some C++ compilers, for
978        example, SunCC recognizes above declarations as different functions and
979        generates broken code for hbpcre." I have changed the declarations to use
980        USPTR.
981    
982    16. GNU libtool is named differently on some systems. The autogen.sh script now
983        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
984        (FreeBSD).
985    
986    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
987        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
988        comment: "Figure out how to create a longlong from a string: strtoll and
989        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
990        instance, but it only takes 2 args instead of 3!"
991    
992    18. A subtle bug concerned with back references has been fixed by a change of
993        specification, with a corresponding code fix. A pattern such as
994        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
995        refers, was giving matches when it shouldn't. For example, xa=xaaa would
996        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
997        same bug. Such groups have to be quantified to be useful, or contained
998        inside another quantified group. (If there's no repetition, the reference
999        can never match.) The problem arises because, having left the group and
1000        moved on to the rest of the pattern, a later failure that backtracks into
1001        the group uses the captured value from the final iteration of the group
1002        rather than the correct earlier one. I have fixed this in PCRE by forcing
1003        any group that contains a reference to itself to be an atomic group; that
1004        is, there cannot be any backtracking into it once it has completed. This is
1005        similar to recursive and subroutine calls.
1006    
1007    
1008    Version 8.00 19-Oct-09
1009    ----------------------
1010    
1011    1.  The table for translating pcre_compile() error codes into POSIX error codes
1012        was out-of-date, and there was no check on the pcre_compile() error code
1013        being within the table. This could lead to an OK return being given in
1014        error.
1015    
1016    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1017        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1018        in a Windows environment.
1019    
1020    3.  The pcregrep --count option prints the count for each file even when it is
1021        zero, as does GNU grep. However, pcregrep was also printing all files when
1022        --files-with-matches was added. Now, when both options are given, it prints
1023        counts only for those files that have at least one match. (GNU grep just
1024        prints the file name in this circumstance, but including the count seems
1025        more useful - otherwise, why use --count?) Also ensured that the
1026        combination -clh just lists non-zero counts, with no names.
1027    
1028    4.  The long form of the pcregrep -F option was incorrectly implemented as
1029        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1030        but it seems right to fix it, and I didn't think it was worth preserving
1031        the old behaviour.
1032    
1033    5.  The command line items --regex=pattern and --regexp=pattern were not
1034        recognized by pcregrep, which required --regex pattern or --regexp pattern
1035        (with a space rather than an '='). The man page documented the '=' forms,
1036        which are compatible with GNU grep; these now work.
1037    
1038    6.  No libpcreposix.pc file was created for pkg-config; there was just
1039        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1040    
1041    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1042        when UCP support is not needed, by modifying the Python script that
1043        generates it from Unicode data files. This should not matter if the module
1044        is correctly used as a library, but I received one complaint about 50K of
1045        unwanted data. My guess is that the person linked everything into his
1046        program rather than using a library. Anyway, it does no harm.
1047    
1048    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1049        was a minimum greater than 1 for a wide character in a possessive
1050        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1051        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1052        character. Chaos in the form of incorrect output or a compiling loop could
1053        result.
1054    
1055    9.  The restrictions on what a pattern can contain when partial matching is
1056        requested for pcre_exec() have been removed. All patterns can now be
1057        partially matched by this function. In addition, if there are at least two
1058        slots in the offset vector, the offset of the earliest inspected character
1059        for the match and the offset of the end of the subject are set in them when
1060        PCRE_ERROR_PARTIAL is returned.
1061    
1062    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1063        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1064        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1065        and may be more useful for multi-segment matching.
1066    
1067    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1068        used to be given if ever the end of the subject was reached; now it is
1069        given only if matching could not proceed because another character was
1070        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1071        string "Z", which now yields "no match" instead of "partial match". In the
1072        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1073        final character ended with (*FAIL).
1074    
1075    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1076        if the pattern had a "must contain" character that was already found in the
1077        earlier partial match, unless partial matching was again requested. For
1078        example, with the pattern /dog.(body)?/, the "must contain" character is
1079        "g". If the first part-match was for the string "dog", restarting with
1080        "sbody" failed. This bug has been fixed.
1081    
1082    13. The string returned by pcre_dfa_exec() after a partial match has been
1083        changed so that it starts at the first inspected character rather than the
1084        first character of the match. This makes a difference only if the pattern
1085        starts with a lookbehind assertion or \b or \B (\K is not supported by
1086        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1087        matching functions compatible, and I think it's the right thing to do.
1088    
1089    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1090        so that the demonstration program is easily available in environments where
1091        PCRE has not been installed from source.
1092    
1093    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1094        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1095        library.
1096    
1097    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1098        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1099        is not the first non-POSIX option to be added. Clearly some people find
1100        these options useful.
1101    
1102    17. If a caller to the POSIX matching function regexec() passes a non-zero
1103        value for nmatch with a NULL value for pmatch, the value of
1104        nmatch is forced to zero.
1105    
1106    18. RunGrepTest did not have a test for the availability of the -u option of
1107        the diff command, as RunTest does. It now checks in the same way as
1108        RunTest, and also checks for the -b option.
1109    
1110    19. If an odd number of negated classes containing just a single character
1111        interposed, within parentheses, between a forward reference to a named
1112        subpattern and the definition of the subpattern, compilation crashed with
1113        an internal error, complaining that it could not find the referenced
1114        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1115        [The bug was that it was starting one character too far in when skipping
1116        over the character class, thus treating the ] as data rather than
1117        terminating the class. This meant it could skip too much.]
1118    
1119    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1120        /g option in pcretest when the pattern contains \K, which makes it possible
1121        to have an empty string match not at the start, even when the pattern is
1122        anchored. Updated pcretest and pcredemo to use this option.
1123    
1124    21. If the maximum number of capturing subpatterns in a recursion was greater
1125        than the maximum at the outer level, the higher number was returned, but
1126        with unset values at the outer level. The correct (outer level) value is
1127        now given.
1128    
1129    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1130        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1131        make it do so. The string so far is captured, making this feature
1132        compatible with Perl.
1133    
1134    23. The tests have been re-organized, adding tests 11 and 12, to make it
1135        possible to check the Perl 5.10 features against Perl 5.10.
1136    
1137    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1138        pattern matches a fixed length string. PCRE did not allow this; now it
1139        does. Neither allows recursion.
1140    
1141    25. I finally figured out how to implement a request to provide the minimum
1142        length of subject string that was needed in order to match a given pattern.
1143        (It was back references and recursion that I had previously got hung up
1144        on.) This code has now been added to pcre_study(); it finds a lower bound
1145        to the length of subject needed. It is not necessarily the greatest lower
1146        bound, but using it to avoid searching strings that are too short does give
1147        some useful speed-ups. The value is available to calling programs via
1148        pcre_fullinfo().
1149    
1150    26. While implementing 25, I discovered to my embarrassment that pcretest had
1151        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1152        study optimizations had never been tested with that matching function.
1153        Oops. What is worse, even when it was passed study data, there was a bug in
1154        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1155        were also very few tests of studied patterns with pcre_dfa_exec().
1156    
1157    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1158        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1159        on the other side of the coin, they are no longer allowed to have different
1160        names, because these cannot be distinguished in PCRE, and this has caused
1161        confusion. (This is a difference from Perl.)
1162    
1163    28. When duplicate subpattern names are present (necessarily with different
1164        numbers, as required by 27 above), and a test is made by name in a
1165        conditional pattern, either for a subpattern having been matched, or for
1166        recursion in such a pattern, all the associated numbered subpatterns are
1167        tested, and the overall condition is true if the condition is true for any
1168        one of them. This is the way Perl works, and is also more like the way
1169        testing by number works.
1170    
1171    
1172    Version 7.9 11-Apr-09
1173    ---------------------
1174    
1175    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1176        (pcretest), all targets were linked against these libraries. This included
1177        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1178        libraries. This caused unwanted dependencies to be created. This problem
1179        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1180        pcretest is linked with readline.
1181    
1182    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1183        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1184        moved outside it again, because FALSE and TRUE are already defined in AIX,
1185        but BOOL is not.
1186    
1187    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1188        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1189    
1190    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1191        hyphens) following file names and line numbers when outputting matching
1192        lines. This is not true; no spaces are inserted. I have also clarified the
1193        wording for the --colour (or --color) option.
1194    
1195    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1196        was not coloured; this is different to GNU grep, so I have changed it to be
1197        the same.
1198    
1199    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1200        each matching line was coloured. Now it goes on to look for further matches
1201        of any of the test patterns, which is the same behaviour as GNU grep.
1202    
1203    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1204        doesn't make sense to accept an empty string match in pcregrep, so I have
1205        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1206        seems to be how GNU grep behaves.
1207    
1208    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1209        start or after a newline", because the conditional assertion was not being
1210        correctly handled. The rule now is that both the assertion and what follows
1211        in the first alternative must satisfy the test.
1212    
1213    9.  If auto-callout was enabled in a pattern with a conditional group whose
1214        condition was an assertion, PCRE could crash during matching, both with
1215        pcre_exec() and pcre_dfa_exec().
1216    
1217    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1218        used for matching.
1219    
1220    11. Unicode property support in character classes was not working for
1221        characters (bytes) greater than 127 when not in UTF-8 mode.
1222    
1223    12. Added the -M command line option to pcretest.
1224    
1225    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1226    
1227    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1228    
1229    16. Added comments and documentation about mis-use of no_arg in the C++
1230        wrapper.
1231    
1232    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1233        from Martin Jerabek that uses macro names for all relevant character and
1234        string constants.
1235    
1236    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1237        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1238        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1239        these, but not everybody uses configure.
1240    
1241    19. A conditional group that had only one branch was not being correctly
1242        recognized as an item that could match an empty string. This meant that an
1243        enclosing group might also not be so recognized, causing infinite looping
1244        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1245        with the subject "ab", where knowledge that the repeated group can match
1246        nothing is needed in order to break the loop.
1247    
1248    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1249        exec(), but without supplying a callout function, matching went wrong.
1250    
1251    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1252        leak if the size of the offset vector was greater than 30. When the vector
1253        is smaller, the saved offsets during recursion go onto a local stack
1254        vector, but for larger vectors malloc() is used. It was failing to free
1255        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1256        error, in fact).
1257    
1258    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1259        heapframe that is used only when UTF-8 support is enabled. This caused no
1260        problem, but was untidy.
1261    
1262    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1263        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1264        included within another project.
1265    
1266    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1267        slightly modified by me:
1268    
1269          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1270              not building pcregrep.
1271    
1272          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1273              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1274    
1275    25. Forward references, both numeric and by name, in patterns that made use of
1276        duplicate group numbers, could behave incorrectly or give incorrect errors,
1277        because when scanning forward to find the reference group, PCRE was not
1278        taking into account the duplicate group numbers. A pattern such as
1279        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1280    
1281    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1282        the feature of a custom pointer more persuasive (as requested by a user).
1283    
1284    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1285        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1286        pre-defined.
1287    
1288    28. Added support for (*UTF8) at the start of a pattern.
1289    
1290    29. Arrange for flags added by the "release type" setting in CMake to be shown
1291        in the configuration summary.
1292    
1293    
1294    Version 7.8 05-Sep-08
1295  ---------------------  ---------------------
1296    
1297  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
1298      Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-      Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1299      stage table and inline lookup instead of a function, giving speed ups of 2      stage table and inline lookup instead of a function, giving speed ups of 2
1300      to 5 times on some simple patterns that I tested. Permission was given to      to 5 times on some simple patterns that I tested. Permission was given to
1301      distribute the MultiStage2.py script that generates the tables (it's not in      distribute the MultiStage2.py script that generates the tables (it's not in
1302      the tarball, but is in the Subversion repository).      the tarball, but is in the Subversion repository).
1303    
1304    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1305        scripts.
1306    
1307    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1308        a group with a zero qualifier. The result of the study could be incorrect,
1309        or the function might crash, depending on the pattern.
1310    
1311    4.  Caseless matching was not working for non-ASCII characters in back
1312        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1313        It now works when Unicode Property Support is available.
1314    
1315    5.  In pcretest, an escape such as \x{de} in the data was always generating
1316        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1317        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1318        truncation.
1319    
1320    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1321    
1322    7.  Added two (int) casts to pcregrep when printing the difference of two
1323        pointers, in case they are 64-bit values.
1324    
1325    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1326        test 2 if it fails.
1327    
1328    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1329        and a #define of that name to empty if it is not externally set. This is to
1330        allow users of MSVC to set it if necessary.
1331    
1332    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1333        the convenience functions in the pcre_get.c source file.
1334    
1335    11. An option change at the start of a pattern that had top-level alternatives
1336        could cause overwriting and/or a crash. This command provoked a crash in
1337        some environments:
1338    
1339          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1340    
1341        This potential security problem was recorded as CVE-2008-2371.
1342    
1343    12. For a pattern where the match had to start at the beginning or immediately
1344        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1345        pcre_dfa_exec() could read past the end of the passed subject if there was
1346        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1347        pcretest so that it places the subject at the end of its malloc-ed buffer.
1348    
1349    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1350        exec() might read past the end of the data buffer in UTF-8 mode.
1351    
1352    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1353        the data contained the byte 0x85 as part of a UTF-8 character within its
1354        first line. This applied both to normal and DFA matching.
1355    
1356    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1357        /^[^d]*?$/8 failed to match "abc".
1358    
1359    16. Added a missing copyright notice to pcrecpp_internal.h.
1360    
1361    17. Make it more clear in the documentation that values returned from
1362        pcre_exec() in ovector are byte offsets, not character counts.
1363    
1364    18. Tidied a few places to stop certain compilers from issuing warnings.
1365    
1366    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1367        supplied by Stefan Weber. I made a further small update for 7.8 because
1368        there is a change of source arrangements: the pcre_searchfuncs.c module is
1369        replaced by pcre_ucd.c.
1370    
1371    
1372  Version 7.7 07-May-08  Version 7.7 07-May-08

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