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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.3 20-Aug-07  Version 8.31
5    -----------------------------
7    1.  Fixing a wrong JIT test case and some compiler warnings.
9    2.  Removed a bashism from the RunTest script.
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)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
36    6.  When matching is performed using JIT-compiled code, the flag bit
37        PCRE_EXTRA_USED_JIT is set in the pcre_extra block and can be tested by the
38        caller. This bit is checked by pcretest if JIT is requested by /S++ or -s++
39        (instead of just /S+ or -s+) and the text "(JIT)" added to the output if
40        the bit is set.
42    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
43        or /S+[+] with a digit between 1 and 7.
46    Version 8.30 04-February-2012
47    -----------------------------
49    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
50        name is defined in ctype.h.
52    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
53        only in quite long subpatterns.
55    3.  Removed the function pcre_info(), which has been obsolete and deprecated
56        since it was replaced by pcre_fullinfo() in February 2000.
58    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
59        match a (*MARK), and the match failed at the start of the subject, a
60        reference to memory before the start of the subject could occur. This bug
61        was introduced by fix 17 of release 8.21.
63    5.  A reference to an unset group with zero minimum repetition was giving
64        totally wrong answers (in non-JavaScript-compatibility mode). For example,
65        /(another)?(\1?)test/ matched against "hello world test". This bug was
66        introduced in release 8.13.
68    6.  Add support for 16-bit character strings (a large amount of work involving
69        many changes and refactorings).
71    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
72        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
73        from a file.
75    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
76        rounding is not applied in this particular case).
78    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
79        if they appear, or are escaped, in patterns.
81    10. Get rid of a number of -Wunused-but-set-variable warnings.
83    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
84        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
85        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
86        also returns the mark "x". This bug applied to capturing parentheses,
87        non-capturing parentheses, and atomic parentheses. It also applied to some
88        assertions.
90    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
91        information out of configure.ac instead of relying on pcre.h.generic, which
92        is not stored in the repository.
94    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
95        -lreadline.
97    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
99    15. Applied Graycode's patch to put the top-level frame on the stack rather
100        than the heap when not using the stack for recursion. This gives a
101        performance improvement in many cases when recursion is not deep.
103    16. Experimental code added to "pcretest -C" to output the stack frame size.
106    Version 8.21 12-Dec-2011
107    ------------------------
109    1.  Updating the JIT compiler.
111    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
112        are added as well.
114    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
115        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
116        calling _pcre_jit_exec. Some extra comments are added.
118    4.  (*MARK) settings inside atomic groups that do not contain any capturing
119        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
120        was introduced by change 18 for 8.20.
122    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
123        ECMA-262 standard.
125    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
126        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
127        This bug was probably introduced by change 9 of 8.13.
129    7.  While fixing 6 above, I noticed that a number of other items were being
130        incorrectly rejected as "not fixed length". This arose partly because newer
131        opcodes had not been added to the fixed-length checking code. I have (a)
132        corrected the bug and added tests for these items, and (b) arranged for an
133        error to occur if an unknown opcode is encountered while checking for fixed
134        length instead of just assuming "not fixed length". The items that were
135        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
136        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
137        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
139    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
140        being incorrectly compiled and would have given unpredicatble results.
142    9.  A possessively repeated subpattern with minimum repeat count greater than
143        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
144        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
145        the first (A) could occur when it should not.
147    10. Add a cast and remove a redundant test from the code.
149    11. JIT should use pcre_malloc/pcre_free for allocation.
151    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
152        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
153        is anything other than /usr, -L is still shown).
155    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
157    14. Perl does not support \N without a following name in a [] class; PCRE now
158        also gives an error.
160    15. If a forward reference was repeated with an upper limit of around 2000,
161        it caused the error "internal error: overran compiling workspace". The
162        maximum number of forward references (including repeats) was limited by the
163        internal workspace, and dependent on the LINK_SIZE. The code has been
164        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
165        the default depends on LINK_SIZE. There is a new upper limit (for safety)
166        of around 200,000 forward references. While doing this, I also speeded up
167        the filling in of repeated forward references.
169    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
170        incorrectly expecting the subject to contain another "a" after the start.
172    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
173        in the match, the SKIP should be ignored. This was not happening; instead
174        the SKIP was being treated as NOMATCH. For patterns such as
175        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
176        tested.
178    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
179        now much more compatible with Perl, in particular in cases where the result
180        is a non-match for a non-anchored pattern. For example, if
181        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
182        "m", where previously it did not return a name. A side effect of this
183        change is that for partial matches, the last encountered mark name is
184        returned, as for non matches. A number of tests that were previously not
185        Perl-compatible have been moved into the Perl-compatible test files. The
186        refactoring has had the pleasing side effect of removing one argument from
187        the match() function, thus reducing its stack requirements.
189    19. If the /S+ option was used in pcretest to study a pattern using JIT,
190        subsequent uses of /S (without +) incorrectly behaved like /S+.
192    21. Retrieve executable code size support for the JIT compiler and fixing
193        some warnings.
195    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
196        not work when the shorter character appeared right at the end of the
197        subject string.
199    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
200        systems.
202    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
203        output it when the /M option is used in pcretest.
205    25. The CheckMan script was not being included in the distribution. Also, added
206        an explicit "perl" to run Perl scripts from the PrepareRelease script
207        because this is reportedly needed in Windows.
209    26. If study data was being save in a file and studying had not found a set of
210        "starts with" bytes for the pattern, the data written to the file (though
211        never used) was taken from uninitialized memory and so caused valgrind to
212        complain.
214    27. Updated RunTest.bat as provided by Sheri Pierce.
216    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
218    29. Computation of memory usage for the table of capturing group names was
219        giving an unnecessarily large value.
222    Version 8.20 21-Oct-2011
223    ------------------------
225    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
226        a POSIX class. After further experiments with Perl, which convinced me that
227        Perl has bugs and confusions, a closing square bracket is no longer allowed
228        in a POSIX name. This bug also affected patterns with classes that started
229        with full stops.
231    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
232        captured substring, but while checking the failing first alternative,
233        substring 1 is temporarily captured. If the output vector supplied to
234        pcre_exec() was not big enough for this capture, the yield of the function
235        was still zero ("insufficient space for captured substrings"). This cannot
236        be totally fixed without adding another stack variable, which seems a lot
237        of expense for a edge case. However, I have improved the situation in cases
238        such as /(a)(b)x|abc/ matched against "abc", where the return code
239        indicates that fewer than the maximum number of slots in the ovector have
240        been set.
242    3.  Related to (2) above: when there are more back references in a pattern than
243        slots in the output vector, pcre_exec() uses temporary memory during
244        matching, and copies in the captures as far as possible afterwards. It was
245        using the entire output vector, but this conflicts with the specification
246        that only 2/3 is used for passing back captured substrings. Now it uses
247        only the first 2/3, for compatibility. This is, of course, another edge
248        case.
250    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
251        main code base, and can be used by building with --enable-jit. When this is
252        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
253        runtime --no-jit option is given.
255    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
256        ovector, the return from the function was zero, implying that there were
257        other matches that did not fit. The correct "exactly full" value is now
258        returned.
260    6.  If a subpattern that was called recursively or as a subroutine contained
261        (*PRUNE) or any other control that caused it to give a non-standard return,
262        invalid errors such as "Error -26 (nested recursion at the same subject
263        position)" or even infinite loops could occur.
265    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
266        computing the minimum length on reaching *ACCEPT, and so ended up with the
267        wrong value of 1 rather than 0. Further investigation indicates that
268        computing a minimum subject length in the presence of *ACCEPT is difficult
269        (think back references, subroutine calls), and so I have changed the code
270        so that no minimum is registered for a pattern that contains *ACCEPT.
272    8.  If (*THEN) was present in the first (true) branch of a conditional group,
273        it was not handled as intended. [But see 16 below.]
275    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
276        Sheri Pierce.
278    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
279        the first byte in a match must be "a".
281    11. Change 17 for 8.13 increased the recursion depth for patterns like
282        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
283        pattern contains any instances of (*THEN). If it does not, the old
284        optimizations are restored. It would be nice to do this on a per-group
285        basis, but at the moment that is not feasible.
287    12. In some environments, the output of pcretest -C is CRLF terminated. This
288        broke RunTest's code that checks for the link size. A single white space
289        character after the value is now allowed for.
291    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
292        For "fr", it uses the Windows-specific input and output files.
294    14. If (*THEN) appeared in a group that was called recursively or as a
295        subroutine, it did not work as intended. [But see next item.]
297    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
298        pattern fragments (but not containing any | characters). If A and B are
299        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
300        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
301        D. In other words, Perl considers parentheses that do not contain any |
302        characters to be part of a surrounding alternative, whereas PCRE was
303        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
304        differently. PCRE now behaves in the same way as Perl, except in the case
305        of subroutine/recursion calls such as (?1) which have in any case always
306        been different (but PCRE had them first :-).
308    16. Related to 15 above: Perl does not treat the | in a conditional group as
309        creating alternatives. Such a group is treated in the same way as an
310        ordinary group without any | characters when processing (*THEN). PCRE has
311        been changed to match Perl's behaviour.
313    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
314        RunGrepTest script failed.
316    18. Change 22 for version 13 caused atomic groups to use more stack. This is
317        inevitable for groups that contain captures, but it can lead to a lot of
318        stack use in large patterns. The old behaviour has been restored for atomic
319        groups that do not contain any capturing parentheses.
321    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
322        suppress the check for a minimum subject length at run time. (If it was
323        given to pcre_exec() or pcre_dfa_exec() it did work.)
325    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
326        fail to work when decoding hex characters in data strings in EBCDIC
327        environments.
329    21. It appears that in at least one Mac OS environment, the isxdigit() function
330        is implemented as a macro that evaluates to its argument more than once,
331        contravening the C 90 Standard (I haven't checked a later standard). There
332        was an instance in pcretest which caused it to go wrong when processing
333        \x{...} escapes in subject strings. The has been rewritten to avoid using
334        things like p++ in the argument of isxdigit().
337    Version 8.13 16-Aug-2011
338    ------------------------
340    1.  The Unicode data tables have been updated to Unicode 6.0.0.
342    2.  Two minor typos in pcre_internal.h have been fixed.
344    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
345        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
346        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
348    4.  There were a number of related bugs in the code for matching backrefences
349        caselessly in UTF-8 mode when codes for the characters concerned were
350        different numbers of bytes. For example, U+023A and U+2C65 are an upper
351        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
352        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
353        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
354        2-byte code at the end of the subject (it thought there wasn't enough data
355        left).
357    5.  Comprehensive information about what went wrong is now returned by
358        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
359        as the output vector has at least 2 elements. The offset of the start of
360        the failing character and a reason code are placed in the vector.
362    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
363        now returned is for the first byte of the failing character, instead of the
364        last byte inspected. This is an incompatible change, but I hope it is small
365        enough not to be a problem. It makes the returned offset consistent with
366        pcre_exec() and pcre_dfa_exec().
368    7.  pcretest now gives a text phrase as well as the error number when
369        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
370        failure, the offset and reason code are output.
372    8.  When \R was used with a maximizing quantifier it failed to skip backwards
373        over a \r\n pair if the subsequent match failed. Instead, it just skipped
374        back over a single character (\n). This seems wrong (because it treated the
375        two characters as a single entity when going forwards), conflicts with the
376        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
377        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
378        has been changed.
380    9.  Some internal refactoring has changed the processing so that the handling
381        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
382        time (the PCRE_DOTALL option was changed this way some time ago: version
383        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
384        which was always a bit of a fudge. It also means that there is one less
385        argument for the match() function, which reduces its stack requirements
386        slightly. This change also fixes an incompatibility with Perl: the pattern
387        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
389    10. More internal refactoring has drastically reduced the number of recursive
390        calls to match() for possessively repeated groups such as (abc)++ when
391        using pcre_exec().
393    11. While implementing 10, a number of bugs in the handling of groups were
394        discovered and fixed:
396        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
397        (a|)*(?1) gave a compile-time internal error.
398        ((a|)+)+  did not notice that the outer group could match an empty string.
399        (^a|^)+   was not marked as anchored.
400        (.*a|.*)+ was not marked as matching at start or after a newline.
402    12. Yet more internal refactoring has removed another argument from the match()
403        function. Special calls to this function are now indicated by setting a
404        value in a variable in the "match data" data block.
406    13. Be more explicit in pcre_study() instead of relying on "default" for
407        opcodes that mean there is no starting character; this means that when new
408        ones are added and accidentally left out of pcre_study(), testing should
409        pick them up.
411    14. The -s option of pcretest has been documented for ages as being an old
412        synonym of -m (show memory usage). I have changed it to mean "force study
413        for every regex", that is, assume /S for every regex. This is similar to -i
414        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
415        using it. It makes it easier to run collections of tests with and without
416        study enabled, and thereby test pcre_study() more easily. All the standard
417        tests are now run with and without -s (but some patterns can be marked as
418        "never study" - see 20 below).
420    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
421        restoration of the capturing data to the outer values was not happening
422        correctly.
424    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
425        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
426        pattern had matched an empty string, and so incorrectly returned a no
427        match.
429    17. There was optimizing code for the last branch of non-capturing parentheses,
430        and also for the obeyed branch of a conditional subexpression, which used
431        tail recursion to cut down on stack usage. Unfortunately, now that there is
432        the possibility of (*THEN) occurring in these branches, tail recursion is
433        no longer possible because the return has to be checked for (*THEN). These
434        two optimizations have therefore been removed. [But see 8.20/11 above.]
436    18. If a pattern containing \R was studied, it was assumed that \R always
437        matched two bytes, thus causing the minimum subject length to be
438        incorrectly computed because \R can also match just one byte.
440    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
441        was incorrectly computed.
443    20. If /S is present twice on a test pattern in pcretest input, it now
444        *disables* studying, thereby overriding the use of -s on the command line
445        (see 14 above). This is necessary for one or two tests to keep the output
446        identical in both cases.
448    21. When (*ACCEPT) was used in an assertion that matched an empty string and
449        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
451    22. When an atomic group that contained a capturing parenthesis was
452        successfully matched, but the branch in which it appeared failed, the
453        capturing was not being forgotten if a higher numbered group was later
454        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
455        group 1 to "a", when in fact it should be unset. This applied to multi-
456        branched capturing and non-capturing groups, repeated or not, and also to
457        positive assertions (capturing in negative assertions does not happen
458        in PCRE) and also to nested atomic groups.
460    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
461        subject after a captured substring, to make it easier to tell which of a
462        number of identical substrings has been captured.
464    24. The way atomic groups are processed by pcre_exec() has been changed so that
465        if they are repeated, backtracking one repetition now resets captured
466        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
467        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
468        "aaa". Previously, it would have been "a". As part of this code
469        refactoring, the way recursive calls are handled has also been changed.
471    25. If an assertion condition captured any substrings, they were not passed
472        back unless some other capturing happened later. For example, if
473        (?(?=(a))a) was matched against "a", no capturing was returned.
475    26. When studying a pattern that contained subroutine calls or assertions,
476        the code for finding the minimum length of a possible match was handling
477        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
478        group 1 called group 2 while simultaneously a separate group 2 called group
479        1). A stack overflow occurred in this case. I have fixed this by limiting
480        the recursion depth to 10.
482    27. Updated RunTest.bat in the distribution to the version supplied by Tom
483        Fortmann. This supports explicit test numbers on the command line, and has
484        argument validation and error reporting.
486    28. An instance of \X with an unlimited repeat could fail if at any point the
487        first character it looked at was a mark character.
489    29. Some minor code refactoring concerning Unicode properties and scripts
490        should reduce the stack requirement of match() slightly.
492    30. Added the '=' option to pcretest to check the setting of unused capturing
493        slots at the end of the pattern, which are documented as being -1, but are
494        not included in the return count.
496    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
497        compiled something random. Now it gives a compile-time error (as does
498        Perl).
500    32. A *MARK encountered during the processing of a positive assertion is now
501        recorded and passed back (compatible with Perl).
503    33. If --only-matching or --colour was set on a pcregrep call whose pattern
504        had alternative anchored branches, the search for a second match in a line
505        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
506        matched the line "0102" twice. The same bug affected patterns that started
507        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
508        twice.
510    34. Previously, PCRE did not allow quantification of assertions. However, Perl
511        does, and because of capturing effects, quantifying parenthesized
512        assertions may at times be useful. Quantifiers are now allowed for
513        parenthesized assertions.
515    35. A minor code tidy in pcre_compile() when checking options for \R usage.
517    36. \g was being checked for fancy things in a character class, when it should
518        just be a literal "g".
520    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
521        appearance of a nested POSIX class supersedes an apparent external class.
522        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
523        unescaped square brackets may also appear as part of class names. For
524        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
525        more like Perl. (But see 8.20/1 above.)
527    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
528        was because it thought it was \N{name}, which is not supported).
530    39. Add minix to OS list not supporting the -S option in pcretest.
532    40. PCRE tries to detect cases of infinite recursion at compile time, but it
533        cannot analyze patterns in sufficient detail to catch mutual recursions
534        such as ((?1))((?2)). There is now a runtime test that gives an error if a
535        subgroup is called recursively as a subpattern for a second time at the
536        same position in the subject string. In previous releases this might have
537        been caught by the recursion limit, or it might have run out of stack.
539    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
540        happen only once. PCRE was, however incorrectly giving a compile time error
541        "recursive call could loop indefinitely" because it cannot analyze the
542        pattern in sufficient detail. The compile time test no longer happens when
543        PCRE is compiling a conditional subpattern, but actual runaway loops are
544        now caught at runtime (see 40 above).
546    42. It seems that Perl allows any characters other than a closing parenthesis
547        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
548        has been changed to be the same.
550    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
551        as not to get warnings when autogen.sh is called. Also changed
552        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
554    44. To help people who use pcregrep to scan files containing exceedingly long
555        lines, the following changes have been made:
557        (a) The default value of the buffer size parameter has been increased from
558            8K to 20K. (The actual buffer used is three times this size.)
560        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
561            PCRE is built.
563        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
564            to be set at run time.
566        (d) Numerical values in pcregrep options can be followed by K or M, for
567            example --buffer-size=50K.
569        (e) If a line being scanned overflows pcregrep's buffer, an error is now
570            given and the return code is set to 2.
572    45. Add a pointer to the latest mark to the callout data block.
574    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
575        partial match of an empty string instead of no match. This was specific to
576        the use of ".".
578    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
579        complete match instead of a partial match. This bug was dependent on both
580        the PCRE_UTF8 and PCRE_DOTALL options being set.
582    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
583        starting byte set, because \b was not being ignored.
586    Version 8.12 15-Jan-2011
587    ------------------------
589    1.  Fixed some typos in the markup of the man pages, and wrote a script that
590        checks for such things as part of the documentation building process.
592    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
593        --match-limit and --recursion-limit options (added for 8.11). In
594        particular, this made one of the standard tests fail. (The integer value
595        went into the wrong half of a long int.)
597    3.  If the --colour option was given to pcregrep with -v (invert match), it
598        did strange things, either producing crazy output, or crashing. It should,
599        of course, ignore a request for colour when reporting lines that do not
600        match.
602    4.  Another pcregrep bug caused similar problems if --colour was specified with
603        -M (multiline) and the pattern match finished with a line ending.
605    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
606        matched in multiline mode, the following line was shown as part of the
607        match. This seems wrong, so I have changed it.
609    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
610        the check for further matches in the same line (so they could be coloured)
611        to overrun the end of the current line. If another match was found, it was
612        incorrectly shown (and then shown again when found in the next line).
614    7.  If pcregrep was compiled under Windows, there was a reference to the
615        function pcregrep_exit() before it was defined. I am assuming this was
616        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
617        reported by a user. I've moved the definition above the reference.
620    Version 8.11 10-Dec-2010
621    ------------------------
623    1.  (*THEN) was not working properly if there were untried alternatives prior
624        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
625        backtracked to try for "b" instead of moving to the next alternative branch
626        at the same level (in this case, to look for "c"). The Perl documentation
627        is clear that when (*THEN) is backtracked onto, it goes to the "next
628        alternative in the innermost enclosing group".
630    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
631        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
632        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
633        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
634        (*THEN).
636    3.  If \s appeared in a character class, it removed the VT character from
637        the class, even if it had been included by some previous item, for example
638        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
639        of \s, but is part of the POSIX "space" class.)
641    4.  A partial match never returns an empty string (because you can always
642        match an empty string at the end of the subject); however the checking for
643        an empty string was starting at the "start of match" point. This has been
644        changed to the "earliest inspected character" point, because the returned
645        data for a partial match starts at this character. This means that, for
646        example, /(?<=abc)def/ gives a partial match for the subject "abc"
647        (previously it gave "no match").
649    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
650        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
651        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
652        has an implication that the given string is incomplete (because a partial
653        match is preferred over a full match). For this reason, these items now
654        give a partial match in this situation. [Aside: previously, the one case
655        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
656        match rather than a full match, which was wrong by the old rules, but is
657        now correct.]
659    6.  There was a bug in the handling of #-introduced comments, recognized when
660        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
661        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
662        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
663        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
664        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
665        places in pcre_compile().
667    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
668        comments when looking ahead for named forward references to subpatterns,
669        the only newline sequence it recognized was NL. It now handles newlines
670        according to the set newline convention.
672    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
673        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
674        cater for a lack of strerror(). These oversights have been fixed.
676    9.  Added --match-limit and --recursion-limit to pcregrep.
678    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
680    11. When the -o option was used, pcregrep was setting a return code of 1, even
681        when matches were found, and --line-buffered was not being honoured.
683    12. Added an optional parentheses number to the -o and --only-matching options
684        of pcregrep.
686    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
687        can match an empty string. The code to do it in pcretest and pcredemo
688        needed fixing:
690        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
691            only one byte after an empty string match just before CRLF (this case
692            just got forgotten; "any" and "anycrlf" were OK).
694        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
695            mode when an empty string match preceded an ASCII character followed by
696            a non-ASCII character. (The code for advancing by one character rather
697            than one byte was nonsense.)
699        (c) The pcredemo.c sample program did not have any code at all to handle
700            the cases when CRLF is a valid newline sequence.
702    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
703        as a starting offset was within the subject string. There is now a new
704        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
705        negative or greater than the length of the string. In order to test this,
706        pcretest is extended to allow the setting of negative starting offsets.
708    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
709        starting offset points to the beginning of a UTF-8 character was
710        unnecessarily clumsy. I tidied it up.
712    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
713        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
715    17. Nobody had reported that the --include_dir option, which was added in
716        release 7.7 should have been called --include-dir (hyphen, not underscore)
717        for compatibility with GNU grep. I have changed it to --include-dir, but
718        left --include_dir as an undocumented synonym, and the same for
719        --exclude-dir, though that is not available in GNU grep, at least as of
720        release 2.5.4.
722    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
723        characters from a string of bytes) have been redefined so as not to use
724        loops, in order to improve performance in some environments. At the same
725        time, I abstracted some of the common code into auxiliary macros to save
726        repetition (this should not affect the compiled code).
728    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
729        compile-time error is now given if \c is not followed by an ASCII
730        character, that is, a byte less than 128. (In EBCDIC mode, the code is
731        different, and any byte value is allowed.)
733    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
734        START_OPTIMIZE option, which is now allowed at compile time - but just
735        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
736        to pcregrep and other applications that have no direct access to PCRE
737        options. The new /Y option in pcretest sets this option when calling
738        pcre_compile().
740    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
741        back references. Groups containing recursive back references were forced to
742        be atomic by that change, but in the case of named groups, the amount of
743        memory required was incorrectly computed, leading to "Failed: internal
744        error: code overflow". This has been fixed.
746    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
747        pcretest.c, to avoid build problems in some Borland environments.
750    Version 8.10 25-Jun-2010
751    ------------------------
753    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
754        THEN.
756    2.  (*ACCEPT) was not working when inside an atomic group.
758    3.  Inside a character class, \B is treated as a literal by default, but
759        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
760        causes the error). The code is unchanged, but I tidied the documentation.
762    4.  Inside a character class, PCRE always treated \R and \X as literals,
763        whereas Perl faults them if its -w option is set. I have changed PCRE so
764        that it faults them when PCRE_EXTRA is set.
766    5.  Added support for \N, which always matches any character other than
767        newline. (It is the same as "." when PCRE_DOTALL is not set.)
769    6.  When compiling pcregrep with newer versions of gcc which may have
770        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
771        declared with attribute warn_unused_result" were given. Just casting the
772        result to (void) does not stop the warnings; a more elaborate fudge is
773        needed. I've used a macro to implement this.
775    7.  Minor change to pcretest.c to avoid a compiler warning.
777    8.  Added four artifical Unicode properties to help with an option to make
778        \s etc use properties (see next item). The new properties are: Xan
779        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
781    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
782        use Unicode properties. (*UCP) at the start of a pattern can be used to set
783        this option. Modified pcretest to add /W to test this facility. Added
784        REG_UCP to make it available via the POSIX interface.
786    10. Added --line-buffered to pcregrep.
788    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
789        studied, and the match started with a letter with a code point greater than
790        127 whose first byte was different to the first byte of the other case of
791        the letter, the other case of this starting letter was not recognized
792        (#976).
794    12. If a pattern that was studied started with a repeated Unicode property
795        test, for example, \p{Nd}+, there was the theoretical possibility of
796        setting up an incorrect bitmap of starting bytes, but fortunately it could
797        not have actually happened in practice until change 8 above was made (it
798        added property types that matched character-matching opcodes).
800    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
801        possible starting bytes for non-anchored patterns.
803    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
804        \R, and also a number of cases that involve Unicode properties, both
805        explicit and implicit when PCRE_UCP is set.
807    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
808        input, it could crash or give wrong results if characters with values
809        greater than 0xc0 were present in the subject string. (Detail: it assumed
810        UTF-8 input when processing these items.)
812    16. Added a lot of (int) casts to avoid compiler warnings in systems where
813        size_t is 64-bit (#991).
815    17. Added a check for running out of memory when PCRE is compiled with
816        --disable-stack-for-recursion (#990).
818    18. If the last data line in a file for pcretest does not have a newline on
819        the end, a newline was missing in the output.
821    19. The default pcre_chartables.c file recognizes only ASCII characters (values
822        less than 128) in its various bitmaps. However, there is a facility for
823        generating tables according to the current locale when PCRE is compiled. It
824        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
825        characters, are recognized by isspace() and therefore were getting set in
826        these tables, and indeed these tables seem to approximate to ISO 8859. This
827        caused a problem in UTF-8 mode when pcre_study() was used to create a list
828        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
829        which of course cannot start UTF-8 characters. I have changed the code so
830        that only real ASCII characters (less than 128) and the correct starting
831        bytes for UTF-8 encodings are set for characters greater than 127 when in
832        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
833        altogether.)
835    20. Added the /T option to pcretest so as to be able to run tests with non-
836        standard character tables, thus making it possible to include the tests
837        used for 19 above in the standard set of tests.
839    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
840        reference to a subpattern the other side of a comment that contains an
841        opening parenthesis caused either an internal compiling error, or a
842        reference to the wrong subpattern.
845    Version 8.02 19-Mar-2010
846    ------------------------
848    1.  The Unicode data tables have been updated to Unicode 5.2.0.
850    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
851        configured.
853    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
854        original author of that file, following a query about its status.
856    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
857        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
859    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
860        quantifier applied to a forward-referencing subroutine call, could compile
861        incorrect code or give the error "internal error: previously-checked
862        referenced subpattern not found".
864    6.  Both MS Visual Studio and Symbian OS have problems with initializing
865        variables to point to external functions. For these systems, therefore,
866        pcre_malloc etc. are now initialized to local functions that call the
867        relevant global functions.
869    7.  There were two entries missing in the vectors called coptable and poptable
870        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
871        I've fixed the data, and added a kludgy way of testing at compile time that
872        the lengths are correct (equal to the number of opcodes).
874    8.  Following on from 7, I added a similar kludge to check the length of the
875        eint vector in pcreposix.c.
877    9.  Error texts for pcre_compile() are held as one long string to avoid too
878        much relocation at load time. To find a text, the string is searched,
879        counting zeros. There was no check for running off the end of the string,
880        which could happen if a new error number was added without updating the
881        string.
883    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
885    11. \K was not working if it appeared in an atomic group or in a group that
886        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
887        \K is "not well defined" if used in an assertion. PCRE now accepts it if
888        the assertion is positive, but not if it is negative.
890    12. Change 11 fortuitously reduced the size of the stack frame used in the
891        "match()" function of pcre_exec.c by one pointer. Forthcoming
892        implementation of support for (*MARK) will need an extra pointer on the
893        stack; I have reserved it now, so that the stack frame size does not
894        decrease.
896    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
897        item in branch that calls a recursion is a subroutine call - as in the
898        second branch in the above example - was incorrectly given the compile-
899        time error "recursive call could loop indefinitely" because pcre_compile()
900        was not correctly checking the subroutine for matching a non-empty string.
902    14. The checks for overrunning compiling workspace could trigger after an
903        overrun had occurred. This is a "should never occur" error, but it can be
904        triggered by pathological patterns such as hundreds of nested parentheses.
905        The checks now trigger 100 bytes before the end of the workspace.
907    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
910    Version 8.01 19-Jan-2010
911    ------------------------
913    1.  If a pattern contained a conditional subpattern with only one branch (in
914        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
915        computed the wrong minimum data length (which is of course zero for such
916        subpatterns). This could cause incorrect "no match" results.
918    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
919        the pattern is reset in the first branch, pcre_compile() failed with
920        "internal error: code overflow at offset...". This happened only when
921        the reset was to the original external option setting. (An optimization
922        abstracts leading options settings into an external setting, which was the
923        cause of this.)
925    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
926        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
927        assertion pattern did not match (meaning that the assertion was true), it
928        was incorrectly treated as false if the SKIP had been reached during the
929        matching. This also applied to assertions used as conditions.
931    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
932        assertion subpattern, including such a pattern used as a condition,
933        unpredictable results occurred, instead of the error return
936    5.  The C++ GlobalReplace function was not working like Perl for the special
937        situation when an empty string is matched. It now does the fancy magic
938        stuff that is necessary.
940    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
941        removed. (These were left over from very, very early versions of PCRE.)
943    7.  Some cosmetic changes to the code to make life easier when compiling it
944        as part of something else:
946        (a) Change DEBUG to PCRE_DEBUG.
948        (b) In pcre_compile(), rename the member of the "branch_chain" structure
949            called "current" as "current_branch", to prevent a collision with the
950            Linux macro when compiled as a kernel module.
952        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
953            prevent a collision with the Linux macro when compiled as a kernel
954            module.
956    8.  In pcre_compile() there are some checks for integer overflows that used to
957        cast potentially large values to (double). This has been changed to that
958        when building, a check for int64_t is made, and if it is found, it is used
959        instead, thus avoiding the use of floating point arithmetic. (There is no
960        other use of FP in PCRE.) If int64_t is not found, the fallback is to
961        double.
963    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
964        2005 (difference between two addresses compared to an unsigned value).
966    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
967        custom one, because of the following reported problem in Windows:
969          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
970              under Win32.
971          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
972              therefore missing the function definition.
973          - The compiler thus generates a "C" signature for the test function.
974          - The linker fails to find the "C" function.
975          - PCRE fails to configure if asked to do so against libbz2.
977    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
978        messages were output:
980          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
981          rerunning libtoolize, to keep the correct libtool macros in-tree.
982          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
984        I have done both of these things.
986    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
987        most of the time, it *can* run out if it is given a pattern that contains a
988        runaway infinite recursion. I updated the discussion in the pcrestack man
989        page.
991    13. Now that we have gone to the x.xx style of version numbers, the minor
992        version may start with zero. Using 08 or 09 is a bad idea because users
993        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
994        interpreted as invalid octal numbers. I've updated the previous comment in
995        configure.ac, and also added a check that gives an error if 08 or 09 are
996        used.
998    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
999        causing partial matching to fail when the end of the subject matched \W
1000        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1002    15. There were some discrepancies between the declarations in pcre_internal.h
1003        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1004        their definitions. The declarations used "const uschar *" and the
1005        definitions used USPTR. Even though USPTR is normally defined as "const
1006        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1007        reported that: "This difference in casting confuses some C++ compilers, for
1008        example, SunCC recognizes above declarations as different functions and
1009        generates broken code for hbpcre." I have changed the declarations to use
1010        USPTR.
1012    16. GNU libtool is named differently on some systems. The autogen.sh script now
1013        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1014        (FreeBSD).
1016    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1017        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1018        comment: "Figure out how to create a longlong from a string: strtoll and
1019        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1020        instance, but it only takes 2 args instead of 3!"
1022    18. A subtle bug concerned with back references has been fixed by a change of
1023        specification, with a corresponding code fix. A pattern such as
1024        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1025        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1026        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1027        same bug. Such groups have to be quantified to be useful, or contained
1028        inside another quantified group. (If there's no repetition, the reference
1029        can never match.) The problem arises because, having left the group and
1030        moved on to the rest of the pattern, a later failure that backtracks into
1031        the group uses the captured value from the final iteration of the group
1032        rather than the correct earlier one. I have fixed this in PCRE by forcing
1033        any group that contains a reference to itself to be an atomic group; that
1034        is, there cannot be any backtracking into it once it has completed. This is
1035        similar to recursive and subroutine calls.
1038    Version 8.00 19-Oct-09
1039    ----------------------
1041    1.  The table for translating pcre_compile() error codes into POSIX error codes
1042        was out-of-date, and there was no check on the pcre_compile() error code
1043        being within the table. This could lead to an OK return being given in
1044        error.
1046    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1047        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1048        in a Windows environment.
1050    3.  The pcregrep --count option prints the count for each file even when it is
1051        zero, as does GNU grep. However, pcregrep was also printing all files when
1052        --files-with-matches was added. Now, when both options are given, it prints
1053        counts only for those files that have at least one match. (GNU grep just
1054        prints the file name in this circumstance, but including the count seems
1055        more useful - otherwise, why use --count?) Also ensured that the
1056        combination -clh just lists non-zero counts, with no names.
1058    4.  The long form of the pcregrep -F option was incorrectly implemented as
1059        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1060        but it seems right to fix it, and I didn't think it was worth preserving
1061        the old behaviour.
1063    5.  The command line items --regex=pattern and --regexp=pattern were not
1064        recognized by pcregrep, which required --regex pattern or --regexp pattern
1065        (with a space rather than an '='). The man page documented the '=' forms,
1066        which are compatible with GNU grep; these now work.
1068    6.  No libpcreposix.pc file was created for pkg-config; there was just
1069        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1071    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1072        when UCP support is not needed, by modifying the Python script that
1073        generates it from Unicode data files. This should not matter if the module
1074        is correctly used as a library, but I received one complaint about 50K of
1075        unwanted data. My guess is that the person linked everything into his
1076        program rather than using a library. Anyway, it does no harm.
1078    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1079        was a minimum greater than 1 for a wide character in a possessive
1080        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1081        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1082        character. Chaos in the form of incorrect output or a compiling loop could
1083        result.
1085    9.  The restrictions on what a pattern can contain when partial matching is
1086        requested for pcre_exec() have been removed. All patterns can now be
1087        partially matched by this function. In addition, if there are at least two
1088        slots in the offset vector, the offset of the earliest inspected character
1089        for the match and the offset of the end of the subject are set in them when
1090        PCRE_ERROR_PARTIAL is returned.
1092    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1093        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1094        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1095        and may be more useful for multi-segment matching.
1097    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1098        used to be given if ever the end of the subject was reached; now it is
1099        given only if matching could not proceed because another character was
1100        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1101        string "Z", which now yields "no match" instead of "partial match". In the
1102        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1103        final character ended with (*FAIL).
1105    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1106        if the pattern had a "must contain" character that was already found in the
1107        earlier partial match, unless partial matching was again requested. For
1108        example, with the pattern /dog.(body)?/, the "must contain" character is
1109        "g". If the first part-match was for the string "dog", restarting with
1110        "sbody" failed. This bug has been fixed.
1112    13. The string returned by pcre_dfa_exec() after a partial match has been
1113        changed so that it starts at the first inspected character rather than the
1114        first character of the match. This makes a difference only if the pattern
1115        starts with a lookbehind assertion or \b or \B (\K is not supported by
1116        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1117        matching functions compatible, and I think it's the right thing to do.
1119    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1120        so that the demonstration program is easily available in environments where
1121        PCRE has not been installed from source.
1123    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1124        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1125        library.
1127    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1128        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1129        is not the first non-POSIX option to be added. Clearly some people find
1130        these options useful.
1132    17. If a caller to the POSIX matching function regexec() passes a non-zero
1133        value for nmatch with a NULL value for pmatch, the value of
1134        nmatch is forced to zero.
1136    18. RunGrepTest did not have a test for the availability of the -u option of
1137        the diff command, as RunTest does. It now checks in the same way as
1138        RunTest, and also checks for the -b option.
1140    19. If an odd number of negated classes containing just a single character
1141        interposed, within parentheses, between a forward reference to a named
1142        subpattern and the definition of the subpattern, compilation crashed with
1143        an internal error, complaining that it could not find the referenced
1144        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1145        [The bug was that it was starting one character too far in when skipping
1146        over the character class, thus treating the ] as data rather than
1147        terminating the class. This meant it could skip too much.]
1149    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1150        /g option in pcretest when the pattern contains \K, which makes it possible
1151        to have an empty string match not at the start, even when the pattern is
1152        anchored. Updated pcretest and pcredemo to use this option.
1154    21. If the maximum number of capturing subpatterns in a recursion was greater
1155        than the maximum at the outer level, the higher number was returned, but
1156        with unset values at the outer level. The correct (outer level) value is
1157        now given.
1159    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1160        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1161        make it do so. The string so far is captured, making this feature
1162        compatible with Perl.
1164    23. The tests have been re-organized, adding tests 11 and 12, to make it
1165        possible to check the Perl 5.10 features against Perl 5.10.
1167    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1168        pattern matches a fixed length string. PCRE did not allow this; now it
1169        does. Neither allows recursion.
1171    25. I finally figured out how to implement a request to provide the minimum
1172        length of subject string that was needed in order to match a given pattern.
1173        (It was back references and recursion that I had previously got hung up
1174        on.) This code has now been added to pcre_study(); it finds a lower bound
1175        to the length of subject needed. It is not necessarily the greatest lower
1176        bound, but using it to avoid searching strings that are too short does give
1177        some useful speed-ups. The value is available to calling programs via
1178        pcre_fullinfo().
1180    26. While implementing 25, I discovered to my embarrassment that pcretest had
1181        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1182        study optimizations had never been tested with that matching function.
1183        Oops. What is worse, even when it was passed study data, there was a bug in
1184        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1185        were also very few tests of studied patterns with pcre_dfa_exec().
1187    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1188        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1189        on the other side of the coin, they are no longer allowed to have different
1190        names, because these cannot be distinguished in PCRE, and this has caused
1191        confusion. (This is a difference from Perl.)
1193    28. When duplicate subpattern names are present (necessarily with different
1194        numbers, as required by 27 above), and a test is made by name in a
1195        conditional pattern, either for a subpattern having been matched, or for
1196        recursion in such a pattern, all the associated numbered subpatterns are
1197        tested, and the overall condition is true if the condition is true for any
1198        one of them. This is the way Perl works, and is also more like the way
1199        testing by number works.
1202    Version 7.9 11-Apr-09
1203    ---------------------
1205    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1206        (pcretest), all targets were linked against these libraries. This included
1207        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1208        libraries. This caused unwanted dependencies to be created. This problem
1209        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1210        pcretest is linked with readline.
1212    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1213        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1214        moved outside it again, because FALSE and TRUE are already defined in AIX,
1215        but BOOL is not.
1217    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1218        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1220    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1221        hyphens) following file names and line numbers when outputting matching
1222        lines. This is not true; no spaces are inserted. I have also clarified the
1223        wording for the --colour (or --color) option.
1225    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1226        was not coloured; this is different to GNU grep, so I have changed it to be
1227        the same.
1229    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1230        each matching line was coloured. Now it goes on to look for further matches
1231        of any of the test patterns, which is the same behaviour as GNU grep.
1233    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1234        doesn't make sense to accept an empty string match in pcregrep, so I have
1235        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1236        seems to be how GNU grep behaves.
1238    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1239        start or after a newline", because the conditional assertion was not being
1240        correctly handled. The rule now is that both the assertion and what follows
1241        in the first alternative must satisfy the test.
1243    9.  If auto-callout was enabled in a pattern with a conditional group whose
1244        condition was an assertion, PCRE could crash during matching, both with
1245        pcre_exec() and pcre_dfa_exec().
1247    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1248        used for matching.
1250    11. Unicode property support in character classes was not working for
1251        characters (bytes) greater than 127 when not in UTF-8 mode.
1253    12. Added the -M command line option to pcretest.
1255    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1257    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1259    16. Added comments and documentation about mis-use of no_arg in the C++
1260        wrapper.
1262    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1263        from Martin Jerabek that uses macro names for all relevant character and
1264        string constants.
1266    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1267        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1268        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1269        these, but not everybody uses configure.
1271    19. A conditional group that had only one branch was not being correctly
1272        recognized as an item that could match an empty string. This meant that an
1273        enclosing group might also not be so recognized, causing infinite looping
1274        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1275        with the subject "ab", where knowledge that the repeated group can match
1276        nothing is needed in order to break the loop.
1278    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1279        exec(), but without supplying a callout function, matching went wrong.
1281    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1282        leak if the size of the offset vector was greater than 30. When the vector
1283        is smaller, the saved offsets during recursion go onto a local stack
1284        vector, but for larger vectors malloc() is used. It was failing to free
1285        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1286        error, in fact).
1288    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1289        heapframe that is used only when UTF-8 support is enabled. This caused no
1290        problem, but was untidy.
1292    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1293        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1294        included within another project.
1296    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1297        slightly modified by me:
1299          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1300              not building pcregrep.
1302          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1303              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1305    25. Forward references, both numeric and by name, in patterns that made use of
1306        duplicate group numbers, could behave incorrectly or give incorrect errors,
1307        because when scanning forward to find the reference group, PCRE was not
1308        taking into account the duplicate group numbers. A pattern such as
1309        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1311    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1312        the feature of a custom pointer more persuasive (as requested by a user).
1314    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1315        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1316        pre-defined.
1318    28. Added support for (*UTF8) at the start of a pattern.
1320    29. Arrange for flags added by the "release type" setting in CMake to be shown
1321        in the configuration summary.
1324    Version 7.8 05-Sep-08
1325    ---------------------
1327    1.  Replaced UCP searching code with optimized version as implemented for Ad
1328        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1329        stage table and inline lookup instead of a function, giving speed ups of 2
1330        to 5 times on some simple patterns that I tested. Permission was given to
1331        distribute the MultiStage2.py script that generates the tables (it's not in
1332        the tarball, but is in the Subversion repository).
1334    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1335        scripts.
1337    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1338        a group with a zero qualifier. The result of the study could be incorrect,
1339        or the function might crash, depending on the pattern.
1341    4.  Caseless matching was not working for non-ASCII characters in back
1342        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1343        It now works when Unicode Property Support is available.
1345    5.  In pcretest, an escape such as \x{de} in the data was always generating
1346        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1347        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1348        truncation.
1350    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1352    7.  Added two (int) casts to pcregrep when printing the difference of two
1353        pointers, in case they are 64-bit values.
1355    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1356        test 2 if it fails.
1358    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1359        and a #define of that name to empty if it is not externally set. This is to
1360        allow users of MSVC to set it if necessary.
1362    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1363        the convenience functions in the pcre_get.c source file.
1365    11. An option change at the start of a pattern that had top-level alternatives
1366        could cause overwriting and/or a crash. This command provoked a crash in
1367        some environments:
1369          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1371        This potential security problem was recorded as CVE-2008-2371.
1373    12. For a pattern where the match had to start at the beginning or immediately
1374        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1375        pcre_dfa_exec() could read past the end of the passed subject if there was
1376        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1377        pcretest so that it places the subject at the end of its malloc-ed buffer.
1379    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1380        exec() might read past the end of the data buffer in UTF-8 mode.
1382    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1383        the data contained the byte 0x85 as part of a UTF-8 character within its
1384        first line. This applied both to normal and DFA matching.
1386    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1387        /^[^d]*?$/8 failed to match "abc".
1389    16. Added a missing copyright notice to pcrecpp_internal.h.
1391    17. Make it more clear in the documentation that values returned from
1392        pcre_exec() in ovector are byte offsets, not character counts.
1394    18. Tidied a few places to stop certain compilers from issuing warnings.
1396    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1397        supplied by Stefan Weber. I made a further small update for 7.8 because
1398        there is a change of source arrangements: the pcre_searchfuncs.c module is
1399        replaced by pcre_ucd.c.
1402    Version 7.7 07-May-08
1403    ---------------------
1405    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1406        a string to a long long, pretend we don't even have a long long." This is
1407        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1409    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1410        pre-7.6 versions, which defined a global no_arg variable instead of putting
1411        it in the RE class. (See also #8 below.)
1413    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1414        Lopes.
1416    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1418        (1) The include/exclude patterns were being applied to the whole pathnames
1419            of files, instead of just to the final components.
1421        (2) If there was more than one level of directory, the subdirectories were
1422            skipped unless they satisfied the include/exclude conditions. This is
1423            inconsistent with GNU grep (and could even be seen as contrary to the
1424            pcregrep specification - which I improved to make it absolutely clear).
1425            The action now is always to scan all levels of directory, and just
1426            apply the include/exclude patterns to regular files.
1428    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1429        --exclude_dir in the tests to avoid scanning .svn directories.
1431    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1432        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1433        doesn't support NULs in patterns.
1435    7.  Added some missing "const"s to declarations of static tables in
1436        pcre_compile.c and pcre_dfa_exec.c.
1438    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1439        caused by fix #2  above. (Subsequently also a second patch to fix the
1440        first patch. And a third patch - this was a messy problem.)
1442    9.  Applied Craig's patch to remove the use of push_back().
1444    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1445        matching function regexec().
1447    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1448        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1449        references. PCRE supports relative numbers with this syntax (I don't think
1450        Oniguruma does).
1452    12. Previously, a group with a zero repeat such as (...){0} was completely
1453        omitted from the compiled regex. However, this means that if the group
1454        was called as a subroutine from elsewhere in the pattern, things went wrong
1455        (an internal error was given). Such groups are now left in the compiled
1456        pattern, with a new opcode that causes them to be skipped at execution
1457        time.
1459    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1460        to the way PCRE behaves:
1462        (a) A lone ] character is dis-allowed (Perl treats it as data).
1464        (b) A back reference to an unmatched subpattern matches an empty string
1465            (Perl fails the current match path).
1467        (c) A data ] in a character class must be notated as \] because if the
1468            first data character in a class is ], it defines an empty class. (In
1469            Perl it is not possible to have an empty class.) The empty class []
1470            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1471            The negative empty class [^] matches any one character, independently
1472            of the DOTALL setting.
1474    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1475        non-existent subpattern following a character class starting with ']' and
1476        containing () gave an internal compiling error instead of "reference to
1477        non-existent subpattern". Fortunately, when the pattern did exist, the
1478        compiled code was correct. (When scanning forwards to check for the
1479        existencd of the subpattern, it was treating the data ']' as terminating
1480        the class, so got the count wrong. When actually compiling, the reference
1481        was subsequently set up correctly.)
1483    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1484        it was being rejected as not supported by pcre_dfa_exec(), even though
1485        other assertions are supported. I have made pcre_dfa_exec() support
1486        (*FAIL).
1488    16. The implementation of 13c above involved the invention of a new opcode,
1489        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1490        cannot be changed at match time, I realized I could make a small
1491        improvement to matching performance by compiling OP_ALLANY instead of
1492        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1493        on the OP_ANY path.
1495    17. Compiling pcretest on Windows with readline support failed without the
1496        following two fixes: (1) Make the unistd.h include conditional on
1497        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1499    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1500        ncurses library to be included for pcretest when ReadLine support is
1501        requested, but also to allow for it to be overridden. This patch came from
1502        Daniel Bergström.
1504    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1505        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1506        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1507        spotting this.
1510    Version 7.6 28-Jan-08
1511    ---------------------
1513    1.  A character class containing a very large number of characters with
1514        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1515        overflow.
1517    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1518        HAVE_LONG_LONG is not defined.
1520    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1521        bring them up to date and include new features. This patch includes:
1523        - Fixed PH's badly added libz and libbz2 support.
1524        - Fixed a problem with static linking.
1525        - Added pcredemo. [But later removed - see 7 below.]
1526        - Fixed dftables problem and added an option.
1527        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1528            HAVE_LONG_LONG.
1529        - Added readline support for pcretest.
1530        - Added an listing of the option settings after cmake has run.
1532    4.  A user submitted a patch to Makefile that makes it easy to create
1533        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1534        Makefile.am that cause it to include this special target, without
1535        affecting anything else. Note that the same mingw target plus all
1536        the other distribution libraries and programs are now supported
1537        when configuring with CMake (see 6 below) instead of with
1538        Configure/Make.
1540    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1541        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1542        exported in the Windows port". It has not yet been confirmed that the patch
1543        solves the problem, but it does no harm.
1545    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1546        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1547        with CMake, and also correct the comment about stack recursion.
1549    7.  Remove the automatic building of pcredemo from the ./configure system and
1550        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1551        of a program that users should build themselves after PCRE is installed, so
1552        building it automatically is not really right. What is more, it gave
1553        trouble in some build environments.
1555    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1558    Version 7.5 10-Jan-08
1559    ---------------------
1561    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1562        values in parens when parsing an RE using the C++ wrapper."
1564    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1565        Characters greater than 255 were excluded from the class instead of being
1566        included.
1568    3.  The same bug as (2) above applied to negated POSIX classes such as
1569        [:^space:].
1571    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1572        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1573        I have changed it.
1575    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1576        first named subpattern) and a construct such as (?&a) would reference the
1577        first named subpattern whose name started with "a" (in other words, the
1578        length check was missing). Both these problems are fixed. "Subpattern name
1579        expected" is now given for (?&) (a zero-length name), and this patch also
1580        makes it give the same error for \k'' (previously it complained that that
1581        was a reference to a non-existent subpattern).
1583    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1584        this is right because (?- can be followed by option settings as well as by
1585        digits. I have, however, made the messages clearer.
1587    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1588        than the number used in the conditional) now cause a compile-time error.
1589        This is actually not compatible with Perl, which accepts such patterns, but
1590        treats the conditional as always being FALSE (as PCRE used to), but it
1591        seems to me that giving a diagnostic is better.
1593    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1594        and messages.
1596    9.  Fix two occurrences of "backslash" in comments that should have been
1597        "backspace".
1599    10. Remove two redundant lines of code that can never be obeyed (their function
1600        was moved elsewhere).
1602    11. The program that makes PCRE's Unicode character property table had a bug
1603        which caused it to generate incorrect table entries for sequences of
1604        characters that have the same character type, but are in different scripts.
1605        It amalgamated them into a single range, with the script of the first of
1606        them. In other words, some characters were in the wrong script. There were
1607        thirteen such cases, affecting characters in the following ranges:
1609          U+002b0 - U+002c1
1610          U+0060c - U+0060d
1611          U+0061e - U+00612
1612          U+0064b - U+0065e
1613          U+0074d - U+0076d
1614          U+01800 - U+01805
1615          U+01d00 - U+01d77
1616          U+01d9b - U+01dbf
1617          U+0200b - U+0200f
1618          U+030fc - U+030fe
1619          U+03260 - U+0327f
1620          U+0fb46 - U+0fbb1
1621          U+10450 - U+1049d
1623    12. The -o option (show only the matching part of a line) for pcregrep was not
1624        compatible with GNU grep in that, if there was more than one match in a
1625        line, it showed only the first of them. It now behaves in the same way as
1626        GNU grep.
1628    13. If the -o and -v options were combined for pcregrep, it printed a blank
1629        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1630        does the same. The return code can be used to tell if there were any
1631        non-matching lines.
1633    14. Added --file-offsets and --line-offsets to pcregrep.
1635    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1636        infinitely looping recursion. The bug was that positive lookaheads were not
1637        being skipped when checking for a possible empty match (negative lookaheads
1638        and both kinds of lookbehind were skipped).
1640    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1641        inclusion of <windows.h> to before rather than after the definition of
1642        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1644    17. Specifying a possessive quantifier with a specific limit for a Unicode
1645        character property caused pcre_compile() to compile bad code, which led at
1646        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1647        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1648        caused the error; without that there was no problem.
1650    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1652    19. Added --enable-pcretest-libreadline.
1654    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1655        RE::GlobalReplace(). As a result, the number of replacements returned was
1656        double what it should be. I removed one of the increments, but Craig sent a
1657        later patch that removed the other one (the right fix) and added unit tests
1658        that check the return values (which was not done before).
1660    21. Several CMake things:
1662        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1663            the names libpcre and libpcreposix, not just pcre and pcreposix.
1665        (2) The above change means that pcretest and pcregrep are now correctly
1666            linked with the newly-built libraries, not previously installed ones.
1670    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1671        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1672        UTF-8 newline character). The key issue is that the pattern starts .*;
1673        this means that the match must be either at the beginning, or after a
1674        newline. The bug was in the code for advancing after a failed match and
1675        checking that the new position followed a newline. It was not taking
1676        account of UTF-8 characters correctly.
1678    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1679        character classes. PCRE was not treating the sequence [:...:] as a
1680        character class unless the ... were all letters. Perl, however, seems to
1681        allow any characters between [: and :], though of course it rejects as
1682        unknown any "names" that contain non-letters, because all the known class
1683        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1684        for example, whereas PCRE did not - it did not recognize a POSIX character
1685        class. This seemed a bit dangerous, so the code has been changed to be
1686        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1687        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1688        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1689        Perl does, and where it didn't before.
1691    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1692        Windows environments %n is disabled by default.
1695    Version 7.4 21-Sep-07
1696    ---------------------
1698    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1699        means that a class such as [\s] counted as "explicit reference to CR or
1700        LF". That isn't really right - the whole point of the change was to try to
1701        help when there was an actual mention of one of the two characters. So now
1702        the change happens only if \r or \n (or a literal CR or LF) character is
1703        encountered.
1705    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1706        of both had grown to the point where there were only 3 bits left.
1707        Fortunately, there was spare space in the data structure, and so I have
1708        moved the internal flags into a new 16-bit field to free up more option
1709        bits.
1711    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1712        but did not set the internal JCHANGED flag - either of these is enough to
1713        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1714        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1715        start sets both bits.
1717    4.  Added options (at build time, compile time, exec time) to change \R from
1718        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1720    5.  doc/pcresyntax.html was missing from the distribution.
1722    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1723        compatibility, even though it is no longer used.
1725    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1726        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1727        windows.h file is present (where different names are used). [This was
1728        reversed later after testing - see 16 below.]
1730    8.  Changed all #include <config.h> to #include "config.h". There were also
1731        some further <pcre.h> cases that I changed to "pcre.h".
1733    9.  When pcregrep was used with the --colour option, it missed the line ending
1734        sequence off the lines that it output.
1736    10. It was pointed out to me that arrays of string pointers cause lots of
1737        relocations when a shared library is dynamically loaded. A technique of
1738        using a single long string with a table of offsets can drastically reduce
1739        these. I have refactored PCRE in four places to do this. The result is
1740        dramatic:
1742          Originally:                          290
1743          After changing UCP table:            187
1744          After changing error message table:   43
1745          After changing table of "verbs"       36
1746          After changing table of Posix names   22
1748        Thanks to the folks working on Gregex for glib for this insight.
1750    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1751        unicode-properties was also set.
1753    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1755    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1756        checked only for CRLF.
1758    14. Added casts to pcretest.c to avoid compiler warnings.
1760    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1762    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1763        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1764        entirely. This removes changes made in 7 above.
1766    17. The CMake files have been updated, and there is now more information about
1767        building with CMake in the NON-UNIX-USE document.
1770    Version 7.3 28-Aug-07
1771  ---------------------  ---------------------
1773   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 145  Version 7.3 20-Aug-07 Line 1911  Version 7.3 20-Aug-07
1912  25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.  25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1914  26. Patterns such as [\P{Yi}A] which include \p or \P and just one other  26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1915      character were causing crashes (broken optimization).      character were causing crashes (broken optimization).
1917    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1918        \p or \P) caused a compile-time loop.
1920    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1921        break. For example, the unstudied pattern [\r\n]A does not match the string
1922        "\r\nA" because change 7.0/46 below moves the current point on by two
1923        characters after failing to match at the start. However, the pattern \nA
1924        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1925        the same is true. There doesn't seem any very clean way out of this, but
1926        what I have chosen to do makes the common cases work: PCRE now takes note
1927        of whether there can be an explicit match for \r or \n anywhere in the
1928        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1929        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1930        pattern has explicit CR or LF references.
1932    29. Added (*CR) etc for changing newline setting at start of pattern.
1935  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07
1936  ---------------------  ---------------------

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