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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.1 12-Mar-07  Version 8.21 05-Dec-2011
5    ------------------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  (*MARK) settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". The
60        maximum number of forward references (including repeats) was limited by the
61        internal workspace, and dependent on the LINK_SIZE. The code has been
62        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
63        the default depends on LINK_SIZE. There is a new upper limit (for safety)
64        of around 200,000 forward references. While doing this, I also speeded up
65        the filling in of repeated forward references.
67    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
68        incorrectly expecting the subject to contain another "a" after the start.
70    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
71        in the match, the SKIP should be ignored. This was not happening; instead
72        the SKIP was being treated as NOMATCH. For patterns such as
73        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
74        tested.
76    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
77        now much more compatible with Perl, in particular in cases where the result
78        is a non-match for a non-anchored pattern. For example, if
79        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
80        "m", where previously it did not return a name. A side effect of this
81        change is that for partial matches, the last encountered mark name is
82        returned, as for non matches. A number of tests that were previously not
83        Perl-compatible have been moved into the Perl-compatible test files. The
84        refactoring has had the pleasing side effect of removing one argument from
85        the match() function, thus reducing its stack requirements.
87    19. If the /S+ option was used in pcretest to study a pattern using JIT,
88        subsequent uses of /S (without +) incorrectly behaved like /S+.
90    21. Retrieve executable code size support for the JIT compiler and fixing
91        some warnings.
93    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
94        not work when the shorter character appeared right at the end of the
95        subject string.
97    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
98        systems.
100    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
101        output it when the /M option is used in pcretest.
103    25. The CheckMan script was not being included in the distribution. Also, added
104        an explicit "perl" to run Perl scripts from the PrepareRelease script
105        because this is reportedly needed in Windows.
107    26. If study data was being save in a file and studying had not found a set of
108        "starts with" bytes for the pattern, the data written to the file (though
109        never used) was taken from uninitialized memory and so caused valgrind to
110        complain.
112    27. Updated RunTest.bat as provided by Sheri Pierce.
115    Version 8.20 21-Oct-2011
116    ------------------------
118    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
119        a POSIX class. After further experiments with Perl, which convinced me that
120        Perl has bugs and confusions, a closing square bracket is no longer allowed
121        in a POSIX name. This bug also affected patterns with classes that started
122        with full stops.
124    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
125        captured substring, but while checking the failing first alternative,
126        substring 1 is temporarily captured. If the output vector supplied to
127        pcre_exec() was not big enough for this capture, the yield of the function
128        was still zero ("insufficient space for captured substrings"). This cannot
129        be totally fixed without adding another stack variable, which seems a lot
130        of expense for a edge case. However, I have improved the situation in cases
131        such as /(a)(b)x|abc/ matched against "abc", where the return code
132        indicates that fewer than the maximum number of slots in the ovector have
133        been set.
135    3.  Related to (2) above: when there are more back references in a pattern than
136        slots in the output vector, pcre_exec() uses temporary memory during
137        matching, and copies in the captures as far as possible afterwards. It was
138        using the entire output vector, but this conflicts with the specification
139        that only 2/3 is used for passing back captured substrings. Now it uses
140        only the first 2/3, for compatibility. This is, of course, another edge
141        case.
143    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
144        main code base, and can be used by building with --enable-jit. When this is
145        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
146        runtime --no-jit option is given.
148    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
149        ovector, the return from the function was zero, implying that there were
150        other matches that did not fit. The correct "exactly full" value is now
151        returned.
153    6.  If a subpattern that was called recursively or as a subroutine contained
154        (*PRUNE) or any other control that caused it to give a non-standard return,
155        invalid errors such as "Error -26 (nested recursion at the same subject
156        position)" or even infinite loops could occur.
158    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
159        computing the minimum length on reaching *ACCEPT, and so ended up with the
160        wrong value of 1 rather than 0. Further investigation indicates that
161        computing a minimum subject length in the presence of *ACCEPT is difficult
162        (think back references, subroutine calls), and so I have changed the code
163        so that no minimum is registered for a pattern that contains *ACCEPT.
165    8.  If (*THEN) was present in the first (true) branch of a conditional group,
166        it was not handled as intended. [But see 16 below.]
168    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
169        Sheri Pierce.
171    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
172        the first byte in a match must be "a".
174    11. Change 17 for 8.13 increased the recursion depth for patterns like
175        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
176        pattern contains any instances of (*THEN). If it does not, the old
177        optimizations are restored. It would be nice to do this on a per-group
178        basis, but at the moment that is not feasible.
180    12. In some environments, the output of pcretest -C is CRLF terminated. This
181        broke RunTest's code that checks for the link size. A single white space
182        character after the value is now allowed for.
184    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
185        For "fr", it uses the Windows-specific input and output files.
187    14. If (*THEN) appeared in a group that was called recursively or as a
188        subroutine, it did not work as intended. [But see next item.]
190    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
191        pattern fragments (but not containing any | characters). If A and B are
192        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
193        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
194        D. In other words, Perl considers parentheses that do not contain any |
195        characters to be part of a surrounding alternative, whereas PCRE was
196        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
197        differently. PCRE now behaves in the same way as Perl, except in the case
198        of subroutine/recursion calls such as (?1) which have in any case always
199        been different (but PCRE had them first :-).
201    16. Related to 15 above: Perl does not treat the | in a conditional group as
202        creating alternatives. Such a group is treated in the same way as an
203        ordinary group without any | characters when processing (*THEN). PCRE has
204        been changed to match Perl's behaviour.
206    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
207        RunGrepTest script failed.
209    18. Change 22 for version 13 caused atomic groups to use more stack. This is
210        inevitable for groups that contain captures, but it can lead to a lot of
211        stack use in large patterns. The old behaviour has been restored for atomic
212        groups that do not contain any capturing parentheses.
214    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
215        suppress the check for a minimum subject length at run time. (If it was
216        given to pcre_exec() or pcre_dfa_exec() it did work.)
218    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
219        fail to work when decoding hex characters in data strings in EBCDIC
220        environments.
222    21. It appears that in at least one Mac OS environment, the isxdigit() function
223        is implemented as a macro that evaluates to its argument more than once,
224        contravening the C 90 Standard (I haven't checked a later standard). There
225        was an instance in pcretest which caused it to go wrong when processing
226        \x{...} escapes in subject strings. The has been rewritten to avoid using
227        things like p++ in the argument of isxdigit().
230    Version 8.13 16-Aug-2011
231    ------------------------
233    1.  The Unicode data tables have been updated to Unicode 6.0.0.
235    2.  Two minor typos in pcre_internal.h have been fixed.
237    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
238        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
239        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
241    4.  There were a number of related bugs in the code for matching backrefences
242        caselessly in UTF-8 mode when codes for the characters concerned were
243        different numbers of bytes. For example, U+023A and U+2C65 are an upper
244        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
245        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
246        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
247        2-byte code at the end of the subject (it thought there wasn't enough data
248        left).
250    5.  Comprehensive information about what went wrong is now returned by
251        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
252        as the output vector has at least 2 elements. The offset of the start of
253        the failing character and a reason code are placed in the vector.
255    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
256        now returned is for the first byte of the failing character, instead of the
257        last byte inspected. This is an incompatible change, but I hope it is small
258        enough not to be a problem. It makes the returned offset consistent with
259        pcre_exec() and pcre_dfa_exec().
261    7.  pcretest now gives a text phrase as well as the error number when
262        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
263        failure, the offset and reason code are output.
265    8.  When \R was used with a maximizing quantifier it failed to skip backwards
266        over a \r\n pair if the subsequent match failed. Instead, it just skipped
267        back over a single character (\n). This seems wrong (because it treated the
268        two characters as a single entity when going forwards), conflicts with the
269        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
270        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
271        has been changed.
273    9.  Some internal refactoring has changed the processing so that the handling
274        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
275        time (the PCRE_DOTALL option was changed this way some time ago: version
276        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
277        which was always a bit of a fudge. It also means that there is one less
278        argument for the match() function, which reduces its stack requirements
279        slightly. This change also fixes an incompatibility with Perl: the pattern
280        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
282    10. More internal refactoring has drastically reduced the number of recursive
283        calls to match() for possessively repeated groups such as (abc)++ when
284        using pcre_exec().
286    11. While implementing 10, a number of bugs in the handling of groups were
287        discovered and fixed:
289        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
290        (a|)*(?1) gave a compile-time internal error.
291        ((a|)+)+  did not notice that the outer group could match an empty string.
292        (^a|^)+   was not marked as anchored.
293        (.*a|.*)+ was not marked as matching at start or after a newline.
295    12. Yet more internal refactoring has removed another argument from the match()
296        function. Special calls to this function are now indicated by setting a
297        value in a variable in the "match data" data block.
299    13. Be more explicit in pcre_study() instead of relying on "default" for
300        opcodes that mean there is no starting character; this means that when new
301        ones are added and accidentally left out of pcre_study(), testing should
302        pick them up.
304    14. The -s option of pcretest has been documented for ages as being an old
305        synonym of -m (show memory usage). I have changed it to mean "force study
306        for every regex", that is, assume /S for every regex. This is similar to -i
307        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
308        using it. It makes it easier to run collections of tests with and without
309        study enabled, and thereby test pcre_study() more easily. All the standard
310        tests are now run with and without -s (but some patterns can be marked as
311        "never study" - see 20 below).
313    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
314        restoration of the capturing data to the outer values was not happening
315        correctly.
317    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
318        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
319        pattern had matched an empty string, and so incorrectly returned a no
320        match.
322    17. There was optimizing code for the last branch of non-capturing parentheses,
323        and also for the obeyed branch of a conditional subexpression, which used
324        tail recursion to cut down on stack usage. Unfortunately, now that there is
325        the possibility of (*THEN) occurring in these branches, tail recursion is
326        no longer possible because the return has to be checked for (*THEN). These
327        two optimizations have therefore been removed. [But see 8.20/11 above.]
329    18. If a pattern containing \R was studied, it was assumed that \R always
330        matched two bytes, thus causing the minimum subject length to be
331        incorrectly computed because \R can also match just one byte.
333    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
334        was incorrectly computed.
336    20. If /S is present twice on a test pattern in pcretest input, it now
337        *disables* studying, thereby overriding the use of -s on the command line
338        (see 14 above). This is necessary for one or two tests to keep the output
339        identical in both cases.
341    21. When (*ACCEPT) was used in an assertion that matched an empty string and
342        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
344    22. When an atomic group that contained a capturing parenthesis was
345        successfully matched, but the branch in which it appeared failed, the
346        capturing was not being forgotten if a higher numbered group was later
347        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
348        group 1 to "a", when in fact it should be unset. This applied to multi-
349        branched capturing and non-capturing groups, repeated or not, and also to
350        positive assertions (capturing in negative assertions does not happen
351        in PCRE) and also to nested atomic groups.
353    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
354        subject after a captured substring, to make it easier to tell which of a
355        number of identical substrings has been captured.
357    24. The way atomic groups are processed by pcre_exec() has been changed so that
358        if they are repeated, backtracking one repetition now resets captured
359        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
360        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
361        "aaa". Previously, it would have been "a". As part of this code
362        refactoring, the way recursive calls are handled has also been changed.
364    25. If an assertion condition captured any substrings, they were not passed
365        back unless some other capturing happened later. For example, if
366        (?(?=(a))a) was matched against "a", no capturing was returned.
368    26. When studying a pattern that contained subroutine calls or assertions,
369        the code for finding the minimum length of a possible match was handling
370        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
371        group 1 called group 2 while simultaneously a separate group 2 called group
372        1). A stack overflow occurred in this case. I have fixed this by limiting
373        the recursion depth to 10.
375    27. Updated RunTest.bat in the distribution to the version supplied by Tom
376        Fortmann. This supports explicit test numbers on the command line, and has
377        argument validation and error reporting.
379    28. An instance of \X with an unlimited repeat could fail if at any point the
380        first character it looked at was a mark character.
382    29. Some minor code refactoring concerning Unicode properties and scripts
383        should reduce the stack requirement of match() slightly.
385    30. Added the '=' option to pcretest to check the setting of unused capturing
386        slots at the end of the pattern, which are documented as being -1, but are
387        not included in the return count.
389    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
390        compiled something random. Now it gives a compile-time error (as does
391        Perl).
393    32. A *MARK encountered during the processing of a positive assertion is now
394        recorded and passed back (compatible with Perl).
396    33. If --only-matching or --colour was set on a pcregrep call whose pattern
397        had alternative anchored branches, the search for a second match in a line
398        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
399        matched the line "0102" twice. The same bug affected patterns that started
400        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
401        twice.
403    34. Previously, PCRE did not allow quantification of assertions. However, Perl
404        does, and because of capturing effects, quantifying parenthesized
405        assertions may at times be useful. Quantifiers are now allowed for
406        parenthesized assertions.
408    35. A minor code tidy in pcre_compile() when checking options for \R usage.
410    36. \g was being checked for fancy things in a character class, when it should
411        just be a literal "g".
413    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
414        appearance of a nested POSIX class supersedes an apparent external class.
415        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
416        unescaped square brackets may also appear as part of class names. For
417        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
418        more like Perl. (But see 8.20/1 above.)
420    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
421        was because it thought it was \N{name}, which is not supported).
423    39. Add minix to OS list not supporting the -S option in pcretest.
425    40. PCRE tries to detect cases of infinite recursion at compile time, but it
426        cannot analyze patterns in sufficient detail to catch mutual recursions
427        such as ((?1))((?2)). There is now a runtime test that gives an error if a
428        subgroup is called recursively as a subpattern for a second time at the
429        same position in the subject string. In previous releases this might have
430        been caught by the recursion limit, or it might have run out of stack.
432    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
433        happen only once. PCRE was, however incorrectly giving a compile time error
434        "recursive call could loop indefinitely" because it cannot analyze the
435        pattern in sufficient detail. The compile time test no longer happens when
436        PCRE is compiling a conditional subpattern, but actual runaway loops are
437        now caught at runtime (see 40 above).
439    42. It seems that Perl allows any characters other than a closing parenthesis
440        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
441        has been changed to be the same.
443    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
444        as not to get warnings when autogen.sh is called. Also changed
445        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
447    44. To help people who use pcregrep to scan files containing exceedingly long
448        lines, the following changes have been made:
450        (a) The default value of the buffer size parameter has been increased from
451            8K to 20K. (The actual buffer used is three times this size.)
453        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
454            PCRE is built.
456        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
457            to be set at run time.
459        (d) Numerical values in pcregrep options can be followed by K or M, for
460            example --buffer-size=50K.
462        (e) If a line being scanned overflows pcregrep's buffer, an error is now
463            given and the return code is set to 2.
465    45. Add a pointer to the latest mark to the callout data block.
467    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
468        partial match of an empty string instead of no match. This was specific to
469        the use of ".".
471    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
472        complete match instead of a partial match. This bug was dependent on both
473        the PCRE_UTF8 and PCRE_DOTALL options being set.
475    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
476        starting byte set, because \b was not being ignored.
479    Version 8.12 15-Jan-2011
480    ------------------------
482    1.  Fixed some typos in the markup of the man pages, and wrote a script that
483        checks for such things as part of the documentation building process.
485    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
486        --match-limit and --recursion-limit options (added for 8.11). In
487        particular, this made one of the standard tests fail. (The integer value
488        went into the wrong half of a long int.)
490    3.  If the --colour option was given to pcregrep with -v (invert match), it
491        did strange things, either producing crazy output, or crashing. It should,
492        of course, ignore a request for colour when reporting lines that do not
493        match.
495    4.  Another pcregrep bug caused similar problems if --colour was specified with
496        -M (multiline) and the pattern match finished with a line ending.
498    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
499        matched in multiline mode, the following line was shown as part of the
500        match. This seems wrong, so I have changed it.
502    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
503        the check for further matches in the same line (so they could be coloured)
504        to overrun the end of the current line. If another match was found, it was
505        incorrectly shown (and then shown again when found in the next line).
507    7.  If pcregrep was compiled under Windows, there was a reference to the
508        function pcregrep_exit() before it was defined. I am assuming this was
509        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
510        reported by a user. I've moved the definition above the reference.
513    Version 8.11 10-Dec-2010
514    ------------------------
516    1.  (*THEN) was not working properly if there were untried alternatives prior
517        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
518        backtracked to try for "b" instead of moving to the next alternative branch
519        at the same level (in this case, to look for "c"). The Perl documentation
520        is clear that when (*THEN) is backtracked onto, it goes to the "next
521        alternative in the innermost enclosing group".
523    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
524        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
525        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
526        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
527        (*THEN).
529    3.  If \s appeared in a character class, it removed the VT character from
530        the class, even if it had been included by some previous item, for example
531        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
532        of \s, but is part of the POSIX "space" class.)
534    4.  A partial match never returns an empty string (because you can always
535        match an empty string at the end of the subject); however the checking for
536        an empty string was starting at the "start of match" point. This has been
537        changed to the "earliest inspected character" point, because the returned
538        data for a partial match starts at this character. This means that, for
539        example, /(?<=abc)def/ gives a partial match for the subject "abc"
540        (previously it gave "no match").
542    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
543        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
544        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
545        has an implication that the given string is incomplete (because a partial
546        match is preferred over a full match). For this reason, these items now
547        give a partial match in this situation. [Aside: previously, the one case
548        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
549        match rather than a full match, which was wrong by the old rules, but is
550        now correct.]
552    6.  There was a bug in the handling of #-introduced comments, recognized when
553        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
554        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
555        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
556        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
557        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
558        places in pcre_compile().
560    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
561        comments when looking ahead for named forward references to subpatterns,
562        the only newline sequence it recognized was NL. It now handles newlines
563        according to the set newline convention.
565    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
566        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
567        cater for a lack of strerror(). These oversights have been fixed.
569    9.  Added --match-limit and --recursion-limit to pcregrep.
571    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
573    11. When the -o option was used, pcregrep was setting a return code of 1, even
574        when matches were found, and --line-buffered was not being honoured.
576    12. Added an optional parentheses number to the -o and --only-matching options
577        of pcregrep.
579    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
580        can match an empty string. The code to do it in pcretest and pcredemo
581        needed fixing:
583        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
584            only one byte after an empty string match just before CRLF (this case
585            just got forgotten; "any" and "anycrlf" were OK).
587        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
588            mode when an empty string match preceded an ASCII character followed by
589            a non-ASCII character. (The code for advancing by one character rather
590            than one byte was nonsense.)
592        (c) The pcredemo.c sample program did not have any code at all to handle
593            the cases when CRLF is a valid newline sequence.
595    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
596        as a starting offset was within the subject string. There is now a new
597        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
598        negative or greater than the length of the string. In order to test this,
599        pcretest is extended to allow the setting of negative starting offsets.
601    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
602        starting offset points to the beginning of a UTF-8 character was
603        unnecessarily clumsy. I tidied it up.
605    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
606        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
608    17. Nobody had reported that the --include_dir option, which was added in
609        release 7.7 should have been called --include-dir (hyphen, not underscore)
610        for compatibility with GNU grep. I have changed it to --include-dir, but
611        left --include_dir as an undocumented synonym, and the same for
612        --exclude-dir, though that is not available in GNU grep, at least as of
613        release 2.5.4.
615    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
616        characters from a string of bytes) have been redefined so as not to use
617        loops, in order to improve performance in some environments. At the same
618        time, I abstracted some of the common code into auxiliary macros to save
619        repetition (this should not affect the compiled code).
621    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
622        compile-time error is now given if \c is not followed by an ASCII
623        character, that is, a byte less than 128. (In EBCDIC mode, the code is
624        different, and any byte value is allowed.)
626    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
627        START_OPTIMIZE option, which is now allowed at compile time - but just
628        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
629        to pcregrep and other applications that have no direct access to PCRE
630        options. The new /Y option in pcretest sets this option when calling
631        pcre_compile().
633    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
634        back references. Groups containing recursive back references were forced to
635        be atomic by that change, but in the case of named groups, the amount of
636        memory required was incorrectly computed, leading to "Failed: internal
637        error: code overflow". This has been fixed.
639    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
640        pcretest.c, to avoid build problems in some Borland environments.
643    Version 8.10 25-Jun-2010
644    ------------------------
646    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
647        THEN.
649    2.  (*ACCEPT) was not working when inside an atomic group.
651    3.  Inside a character class, \B is treated as a literal by default, but
652        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
653        causes the error). The code is unchanged, but I tidied the documentation.
655    4.  Inside a character class, PCRE always treated \R and \X as literals,
656        whereas Perl faults them if its -w option is set. I have changed PCRE so
657        that it faults them when PCRE_EXTRA is set.
659    5.  Added support for \N, which always matches any character other than
660        newline. (It is the same as "." when PCRE_DOTALL is not set.)
662    6.  When compiling pcregrep with newer versions of gcc which may have
663        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
664        declared with attribute warn_unused_result" were given. Just casting the
665        result to (void) does not stop the warnings; a more elaborate fudge is
666        needed. I've used a macro to implement this.
668    7.  Minor change to pcretest.c to avoid a compiler warning.
670    8.  Added four artifical Unicode properties to help with an option to make
671        \s etc use properties (see next item). The new properties are: Xan
672        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
674    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
675        use Unicode properties. (*UCP) at the start of a pattern can be used to set
676        this option. Modified pcretest to add /W to test this facility. Added
677        REG_UCP to make it available via the POSIX interface.
679    10. Added --line-buffered to pcregrep.
681    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
682        studied, and the match started with a letter with a code point greater than
683        127 whose first byte was different to the first byte of the other case of
684        the letter, the other case of this starting letter was not recognized
685        (#976).
687    12. If a pattern that was studied started with a repeated Unicode property
688        test, for example, \p{Nd}+, there was the theoretical possibility of
689        setting up an incorrect bitmap of starting bytes, but fortunately it could
690        not have actually happened in practice until change 8 above was made (it
691        added property types that matched character-matching opcodes).
693    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
694        possible starting bytes for non-anchored patterns.
696    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
697        \R, and also a number of cases that involve Unicode properties, both
698        explicit and implicit when PCRE_UCP is set.
700    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
701        input, it could crash or give wrong results if characters with values
702        greater than 0xc0 were present in the subject string. (Detail: it assumed
703        UTF-8 input when processing these items.)
705    16. Added a lot of (int) casts to avoid compiler warnings in systems where
706        size_t is 64-bit (#991).
708    17. Added a check for running out of memory when PCRE is compiled with
709        --disable-stack-for-recursion (#990).
711    18. If the last data line in a file for pcretest does not have a newline on
712        the end, a newline was missing in the output.
714    19. The default pcre_chartables.c file recognizes only ASCII characters (values
715        less than 128) in its various bitmaps. However, there is a facility for
716        generating tables according to the current locale when PCRE is compiled. It
717        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
718        characters, are recognized by isspace() and therefore were getting set in
719        these tables, and indeed these tables seem to approximate to ISO 8859. This
720        caused a problem in UTF-8 mode when pcre_study() was used to create a list
721        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
722        which of course cannot start UTF-8 characters. I have changed the code so
723        that only real ASCII characters (less than 128) and the correct starting
724        bytes for UTF-8 encodings are set for characters greater than 127 when in
725        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
726        altogether.)
728    20. Added the /T option to pcretest so as to be able to run tests with non-
729        standard character tables, thus making it possible to include the tests
730        used for 19 above in the standard set of tests.
732    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
733        reference to a subpattern the other side of a comment that contains an
734        opening parenthesis caused either an internal compiling error, or a
735        reference to the wrong subpattern.
738    Version 8.02 19-Mar-2010
739    ------------------------
741    1.  The Unicode data tables have been updated to Unicode 5.2.0.
743    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
744        configured.
746    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
747        original author of that file, following a query about its status.
749    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
750        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
752    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
753        quantifier applied to a forward-referencing subroutine call, could compile
754        incorrect code or give the error "internal error: previously-checked
755        referenced subpattern not found".
757    6.  Both MS Visual Studio and Symbian OS have problems with initializing
758        variables to point to external functions. For these systems, therefore,
759        pcre_malloc etc. are now initialized to local functions that call the
760        relevant global functions.
762    7.  There were two entries missing in the vectors called coptable and poptable
763        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
764        I've fixed the data, and added a kludgy way of testing at compile time that
765        the lengths are correct (equal to the number of opcodes).
767    8.  Following on from 7, I added a similar kludge to check the length of the
768        eint vector in pcreposix.c.
770    9.  Error texts for pcre_compile() are held as one long string to avoid too
771        much relocation at load time. To find a text, the string is searched,
772        counting zeros. There was no check for running off the end of the string,
773        which could happen if a new error number was added without updating the
774        string.
776    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
778    11. \K was not working if it appeared in an atomic group or in a group that
779        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
780        \K is "not well defined" if used in an assertion. PCRE now accepts it if
781        the assertion is positive, but not if it is negative.
783    12. Change 11 fortuitously reduced the size of the stack frame used in the
784        "match()" function of pcre_exec.c by one pointer. Forthcoming
785        implementation of support for (*MARK) will need an extra pointer on the
786        stack; I have reserved it now, so that the stack frame size does not
787        decrease.
789    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
790        item in branch that calls a recursion is a subroutine call - as in the
791        second branch in the above example - was incorrectly given the compile-
792        time error "recursive call could loop indefinitely" because pcre_compile()
793        was not correctly checking the subroutine for matching a non-empty string.
795    14. The checks for overrunning compiling workspace could trigger after an
796        overrun had occurred. This is a "should never occur" error, but it can be
797        triggered by pathological patterns such as hundreds of nested parentheses.
798        The checks now trigger 100 bytes before the end of the workspace.
800    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
803    Version 8.01 19-Jan-2010
804    ------------------------
806    1.  If a pattern contained a conditional subpattern with only one branch (in
807        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
808        computed the wrong minimum data length (which is of course zero for such
809        subpatterns). This could cause incorrect "no match" results.
811    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
812        the pattern is reset in the first branch, pcre_compile() failed with
813        "internal error: code overflow at offset...". This happened only when
814        the reset was to the original external option setting. (An optimization
815        abstracts leading options settings into an external setting, which was the
816        cause of this.)
818    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
819        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
820        assertion pattern did not match (meaning that the assertion was true), it
821        was incorrectly treated as false if the SKIP had been reached during the
822        matching. This also applied to assertions used as conditions.
824    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
825        assertion subpattern, including such a pattern used as a condition,
826        unpredictable results occurred, instead of the error return
829    5.  The C++ GlobalReplace function was not working like Perl for the special
830        situation when an empty string is matched. It now does the fancy magic
831        stuff that is necessary.
833    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
834        removed. (These were left over from very, very early versions of PCRE.)
836    7.  Some cosmetic changes to the code to make life easier when compiling it
837        as part of something else:
839        (a) Change DEBUG to PCRE_DEBUG.
841        (b) In pcre_compile(), rename the member of the "branch_chain" structure
842            called "current" as "current_branch", to prevent a collision with the
843            Linux macro when compiled as a kernel module.
845        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
846            prevent a collision with the Linux macro when compiled as a kernel
847            module.
849    8.  In pcre_compile() there are some checks for integer overflows that used to
850        cast potentially large values to (double). This has been changed to that
851        when building, a check for int64_t is made, and if it is found, it is used
852        instead, thus avoiding the use of floating point arithmetic. (There is no
853        other use of FP in PCRE.) If int64_t is not found, the fallback is to
854        double.
856    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
857        2005 (difference between two addresses compared to an unsigned value).
859    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
860        custom one, because of the following reported problem in Windows:
862          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
863              under Win32.
864          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
865              therefore missing the function definition.
866          - The compiler thus generates a "C" signature for the test function.
867          - The linker fails to find the "C" function.
868          - PCRE fails to configure if asked to do so against libbz2.
870    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
871        messages were output:
873          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
874          rerunning libtoolize, to keep the correct libtool macros in-tree.
875          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
877        I have done both of these things.
879    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
880        most of the time, it *can* run out if it is given a pattern that contains a
881        runaway infinite recursion. I updated the discussion in the pcrestack man
882        page.
884    13. Now that we have gone to the x.xx style of version numbers, the minor
885        version may start with zero. Using 08 or 09 is a bad idea because users
886        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
887        interpreted as invalid octal numbers. I've updated the previous comment in
888        configure.ac, and also added a check that gives an error if 08 or 09 are
889        used.
891    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
892        causing partial matching to fail when the end of the subject matched \W
893        in a UTF-8 pattern where \W was quantified with a minimum of 3.
895    15. There were some discrepancies between the declarations in pcre_internal.h
896        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
897        their definitions. The declarations used "const uschar *" and the
898        definitions used USPTR. Even though USPTR is normally defined as "const
899        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
900        reported that: "This difference in casting confuses some C++ compilers, for
901        example, SunCC recognizes above declarations as different functions and
902        generates broken code for hbpcre." I have changed the declarations to use
903        USPTR.
905    16. GNU libtool is named differently on some systems. The autogen.sh script now
906        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
907        (FreeBSD).
909    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
910        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
911        comment: "Figure out how to create a longlong from a string: strtoll and
912        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
913        instance, but it only takes 2 args instead of 3!"
915    18. A subtle bug concerned with back references has been fixed by a change of
916        specification, with a corresponding code fix. A pattern such as
917        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
918        refers, was giving matches when it shouldn't. For example, xa=xaaa would
919        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
920        same bug. Such groups have to be quantified to be useful, or contained
921        inside another quantified group. (If there's no repetition, the reference
922        can never match.) The problem arises because, having left the group and
923        moved on to the rest of the pattern, a later failure that backtracks into
924        the group uses the captured value from the final iteration of the group
925        rather than the correct earlier one. I have fixed this in PCRE by forcing
926        any group that contains a reference to itself to be an atomic group; that
927        is, there cannot be any backtracking into it once it has completed. This is
928        similar to recursive and subroutine calls.
931    Version 8.00 19-Oct-09
932    ----------------------
934    1.  The table for translating pcre_compile() error codes into POSIX error codes
935        was out-of-date, and there was no check on the pcre_compile() error code
936        being within the table. This could lead to an OK return being given in
937        error.
939    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
940        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
941        in a Windows environment.
943    3.  The pcregrep --count option prints the count for each file even when it is
944        zero, as does GNU grep. However, pcregrep was also printing all files when
945        --files-with-matches was added. Now, when both options are given, it prints
946        counts only for those files that have at least one match. (GNU grep just
947        prints the file name in this circumstance, but including the count seems
948        more useful - otherwise, why use --count?) Also ensured that the
949        combination -clh just lists non-zero counts, with no names.
951    4.  The long form of the pcregrep -F option was incorrectly implemented as
952        --fixed_strings instead of --fixed-strings. This is an incompatible change,
953        but it seems right to fix it, and I didn't think it was worth preserving
954        the old behaviour.
956    5.  The command line items --regex=pattern and --regexp=pattern were not
957        recognized by pcregrep, which required --regex pattern or --regexp pattern
958        (with a space rather than an '='). The man page documented the '=' forms,
959        which are compatible with GNU grep; these now work.
961    6.  No libpcreposix.pc file was created for pkg-config; there was just
962        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
964    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
965        when UCP support is not needed, by modifying the Python script that
966        generates it from Unicode data files. This should not matter if the module
967        is correctly used as a library, but I received one complaint about 50K of
968        unwanted data. My guess is that the person linked everything into his
969        program rather than using a library. Anyway, it does no harm.
971    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
972        was a minimum greater than 1 for a wide character in a possessive
973        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
974        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
975        character. Chaos in the form of incorrect output or a compiling loop could
976        result.
978    9.  The restrictions on what a pattern can contain when partial matching is
979        requested for pcre_exec() have been removed. All patterns can now be
980        partially matched by this function. In addition, if there are at least two
981        slots in the offset vector, the offset of the earliest inspected character
982        for the match and the offset of the end of the subject are set in them when
983        PCRE_ERROR_PARTIAL is returned.
985    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
986        synonymous with PCRE_PARTIAL, for backwards compatibility, and
987        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
988        and may be more useful for multi-segment matching.
990    11. Partial matching with pcre_exec() is now more intuitive. A partial match
991        used to be given if ever the end of the subject was reached; now it is
992        given only if matching could not proceed because another character was
993        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
994        string "Z", which now yields "no match" instead of "partial match". In the
995        case of pcre_dfa_exec(), "no match" is given if every matching path for the
996        final character ended with (*FAIL).
998    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
999        if the pattern had a "must contain" character that was already found in the
1000        earlier partial match, unless partial matching was again requested. For
1001        example, with the pattern /dog.(body)?/, the "must contain" character is
1002        "g". If the first part-match was for the string "dog", restarting with
1003        "sbody" failed. This bug has been fixed.
1005    13. The string returned by pcre_dfa_exec() after a partial match has been
1006        changed so that it starts at the first inspected character rather than the
1007        first character of the match. This makes a difference only if the pattern
1008        starts with a lookbehind assertion or \b or \B (\K is not supported by
1009        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1010        matching functions compatible, and I think it's the right thing to do.
1012    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1013        so that the demonstration program is easily available in environments where
1014        PCRE has not been installed from source.
1016    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1017        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1018        library.
1020    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1021        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1022        is not the first non-POSIX option to be added. Clearly some people find
1023        these options useful.
1025    17. If a caller to the POSIX matching function regexec() passes a non-zero
1026        value for nmatch with a NULL value for pmatch, the value of
1027        nmatch is forced to zero.
1029    18. RunGrepTest did not have a test for the availability of the -u option of
1030        the diff command, as RunTest does. It now checks in the same way as
1031        RunTest, and also checks for the -b option.
1033    19. If an odd number of negated classes containing just a single character
1034        interposed, within parentheses, between a forward reference to a named
1035        subpattern and the definition of the subpattern, compilation crashed with
1036        an internal error, complaining that it could not find the referenced
1037        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1038        [The bug was that it was starting one character too far in when skipping
1039        over the character class, thus treating the ] as data rather than
1040        terminating the class. This meant it could skip too much.]
1042    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1043        /g option in pcretest when the pattern contains \K, which makes it possible
1044        to have an empty string match not at the start, even when the pattern is
1045        anchored. Updated pcretest and pcredemo to use this option.
1047    21. If the maximum number of capturing subpatterns in a recursion was greater
1048        than the maximum at the outer level, the higher number was returned, but
1049        with unset values at the outer level. The correct (outer level) value is
1050        now given.
1052    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1053        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1054        make it do so. The string so far is captured, making this feature
1055        compatible with Perl.
1057    23. The tests have been re-organized, adding tests 11 and 12, to make it
1058        possible to check the Perl 5.10 features against Perl 5.10.
1060    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1061        pattern matches a fixed length string. PCRE did not allow this; now it
1062        does. Neither allows recursion.
1064    25. I finally figured out how to implement a request to provide the minimum
1065        length of subject string that was needed in order to match a given pattern.
1066        (It was back references and recursion that I had previously got hung up
1067        on.) This code has now been added to pcre_study(); it finds a lower bound
1068        to the length of subject needed. It is not necessarily the greatest lower
1069        bound, but using it to avoid searching strings that are too short does give
1070        some useful speed-ups. The value is available to calling programs via
1071        pcre_fullinfo().
1073    26. While implementing 25, I discovered to my embarrassment that pcretest had
1074        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1075        study optimizations had never been tested with that matching function.
1076        Oops. What is worse, even when it was passed study data, there was a bug in
1077        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1078        were also very few tests of studied patterns with pcre_dfa_exec().
1080    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1081        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1082        on the other side of the coin, they are no longer allowed to have different
1083        names, because these cannot be distinguished in PCRE, and this has caused
1084        confusion. (This is a difference from Perl.)
1086    28. When duplicate subpattern names are present (necessarily with different
1087        numbers, as required by 27 above), and a test is made by name in a
1088        conditional pattern, either for a subpattern having been matched, or for
1089        recursion in such a pattern, all the associated numbered subpatterns are
1090        tested, and the overall condition is true if the condition is true for any
1091        one of them. This is the way Perl works, and is also more like the way
1092        testing by number works.
1095    Version 7.9 11-Apr-09
1096    ---------------------
1098    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1099        (pcretest), all targets were linked against these libraries. This included
1100        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1101        libraries. This caused unwanted dependencies to be created. This problem
1102        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1103        pcretest is linked with readline.
1105    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1106        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1107        moved outside it again, because FALSE and TRUE are already defined in AIX,
1108        but BOOL is not.
1110    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1111        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1113    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1114        hyphens) following file names and line numbers when outputting matching
1115        lines. This is not true; no spaces are inserted. I have also clarified the
1116        wording for the --colour (or --color) option.
1118    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1119        was not coloured; this is different to GNU grep, so I have changed it to be
1120        the same.
1122    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1123        each matching line was coloured. Now it goes on to look for further matches
1124        of any of the test patterns, which is the same behaviour as GNU grep.
1126    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1127        doesn't make sense to accept an empty string match in pcregrep, so I have
1128        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1129        seems to be how GNU grep behaves.
1131    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1132        start or after a newline", because the conditional assertion was not being
1133        correctly handled. The rule now is that both the assertion and what follows
1134        in the first alternative must satisfy the test.
1136    9.  If auto-callout was enabled in a pattern with a conditional group whose
1137        condition was an assertion, PCRE could crash during matching, both with
1138        pcre_exec() and pcre_dfa_exec().
1140    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1141        used for matching.
1143    11. Unicode property support in character classes was not working for
1144        characters (bytes) greater than 127 when not in UTF-8 mode.
1146    12. Added the -M command line option to pcretest.
1148    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1150    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1152    16. Added comments and documentation about mis-use of no_arg in the C++
1153        wrapper.
1155    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1156        from Martin Jerabek that uses macro names for all relevant character and
1157        string constants.
1159    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1160        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1161        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1162        these, but not everybody uses configure.
1164    19. A conditional group that had only one branch was not being correctly
1165        recognized as an item that could match an empty string. This meant that an
1166        enclosing group might also not be so recognized, causing infinite looping
1167        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1168        with the subject "ab", where knowledge that the repeated group can match
1169        nothing is needed in order to break the loop.
1171    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1172        exec(), but without supplying a callout function, matching went wrong.
1174    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1175        leak if the size of the offset vector was greater than 30. When the vector
1176        is smaller, the saved offsets during recursion go onto a local stack
1177        vector, but for larger vectors malloc() is used. It was failing to free
1178        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1179        error, in fact).
1181    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1182        heapframe that is used only when UTF-8 support is enabled. This caused no
1183        problem, but was untidy.
1185    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1186        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1187        included within another project.
1189    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1190        slightly modified by me:
1192          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1193              not building pcregrep.
1195          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1196              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1198    25. Forward references, both numeric and by name, in patterns that made use of
1199        duplicate group numbers, could behave incorrectly or give incorrect errors,
1200        because when scanning forward to find the reference group, PCRE was not
1201        taking into account the duplicate group numbers. A pattern such as
1202        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1204    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1205        the feature of a custom pointer more persuasive (as requested by a user).
1207    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1208        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1209        pre-defined.
1211    28. Added support for (*UTF8) at the start of a pattern.
1213    29. Arrange for flags added by the "release type" setting in CMake to be shown
1214        in the configuration summary.
1217    Version 7.8 05-Sep-08
1218    ---------------------
1220    1.  Replaced UCP searching code with optimized version as implemented for Ad
1221        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1222        stage table and inline lookup instead of a function, giving speed ups of 2
1223        to 5 times on some simple patterns that I tested. Permission was given to
1224        distribute the MultiStage2.py script that generates the tables (it's not in
1225        the tarball, but is in the Subversion repository).
1227    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1228        scripts.
1230    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1231        a group with a zero qualifier. The result of the study could be incorrect,
1232        or the function might crash, depending on the pattern.
1234    4.  Caseless matching was not working for non-ASCII characters in back
1235        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1236        It now works when Unicode Property Support is available.
1238    5.  In pcretest, an escape such as \x{de} in the data was always generating
1239        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1240        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1241        truncation.
1243    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1245    7.  Added two (int) casts to pcregrep when printing the difference of two
1246        pointers, in case they are 64-bit values.
1248    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1249        test 2 if it fails.
1251    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1252        and a #define of that name to empty if it is not externally set. This is to
1253        allow users of MSVC to set it if necessary.
1255    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1256        the convenience functions in the pcre_get.c source file.
1258    11. An option change at the start of a pattern that had top-level alternatives
1259        could cause overwriting and/or a crash. This command provoked a crash in
1260        some environments:
1262          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1264        This potential security problem was recorded as CVE-2008-2371.
1266    12. For a pattern where the match had to start at the beginning or immediately
1267        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1268        pcre_dfa_exec() could read past the end of the passed subject if there was
1269        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1270        pcretest so that it places the subject at the end of its malloc-ed buffer.
1272    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1273        exec() might read past the end of the data buffer in UTF-8 mode.
1275    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1276        the data contained the byte 0x85 as part of a UTF-8 character within its
1277        first line. This applied both to normal and DFA matching.
1279    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1280        /^[^d]*?$/8 failed to match "abc".
1282    16. Added a missing copyright notice to pcrecpp_internal.h.
1284    17. Make it more clear in the documentation that values returned from
1285        pcre_exec() in ovector are byte offsets, not character counts.
1287    18. Tidied a few places to stop certain compilers from issuing warnings.
1289    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1290        supplied by Stefan Weber. I made a further small update for 7.8 because
1291        there is a change of source arrangements: the pcre_searchfuncs.c module is
1292        replaced by pcre_ucd.c.
1295    Version 7.7 07-May-08
1296    ---------------------
1298    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1299        a string to a long long, pretend we don't even have a long long." This is
1300        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1302    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1303        pre-7.6 versions, which defined a global no_arg variable instead of putting
1304        it in the RE class. (See also #8 below.)
1306    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1307        Lopes.
1309    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1311        (1) The include/exclude patterns were being applied to the whole pathnames
1312            of files, instead of just to the final components.
1314        (2) If there was more than one level of directory, the subdirectories were
1315            skipped unless they satisfied the include/exclude conditions. This is
1316            inconsistent with GNU grep (and could even be seen as contrary to the
1317            pcregrep specification - which I improved to make it absolutely clear).
1318            The action now is always to scan all levels of directory, and just
1319            apply the include/exclude patterns to regular files.
1321    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1322        --exclude_dir in the tests to avoid scanning .svn directories.
1324    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1325        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1326        doesn't support NULs in patterns.
1328    7.  Added some missing "const"s to declarations of static tables in
1329        pcre_compile.c and pcre_dfa_exec.c.
1331    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1332        caused by fix #2  above. (Subsequently also a second patch to fix the
1333        first patch. And a third patch - this was a messy problem.)
1335    9.  Applied Craig's patch to remove the use of push_back().
1337    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1338        matching function regexec().
1340    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1341        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1342        references. PCRE supports relative numbers with this syntax (I don't think
1343        Oniguruma does).
1345    12. Previously, a group with a zero repeat such as (...){0} was completely
1346        omitted from the compiled regex. However, this means that if the group
1347        was called as a subroutine from elsewhere in the pattern, things went wrong
1348        (an internal error was given). Such groups are now left in the compiled
1349        pattern, with a new opcode that causes them to be skipped at execution
1350        time.
1352    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1353        to the way PCRE behaves:
1355        (a) A lone ] character is dis-allowed (Perl treats it as data).
1357        (b) A back reference to an unmatched subpattern matches an empty string
1358            (Perl fails the current match path).
1360        (c) A data ] in a character class must be notated as \] because if the
1361            first data character in a class is ], it defines an empty class. (In
1362            Perl it is not possible to have an empty class.) The empty class []
1363            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1364            The negative empty class [^] matches any one character, independently
1365            of the DOTALL setting.
1367    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1368        non-existent subpattern following a character class starting with ']' and
1369        containing () gave an internal compiling error instead of "reference to
1370        non-existent subpattern". Fortunately, when the pattern did exist, the
1371        compiled code was correct. (When scanning forwards to check for the
1372        existencd of the subpattern, it was treating the data ']' as terminating
1373        the class, so got the count wrong. When actually compiling, the reference
1374        was subsequently set up correctly.)
1376    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1377        it was being rejected as not supported by pcre_dfa_exec(), even though
1378        other assertions are supported. I have made pcre_dfa_exec() support
1379        (*FAIL).
1381    16. The implementation of 13c above involved the invention of a new opcode,
1382        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1383        cannot be changed at match time, I realized I could make a small
1384        improvement to matching performance by compiling OP_ALLANY instead of
1385        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1386        on the OP_ANY path.
1388    17. Compiling pcretest on Windows with readline support failed without the
1389        following two fixes: (1) Make the unistd.h include conditional on
1390        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1392    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1393        ncurses library to be included for pcretest when ReadLine support is
1394        requested, but also to allow for it to be overridden. This patch came from
1395        Daniel Bergström.
1397    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1398        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1399        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1400        spotting this.
1403    Version 7.6 28-Jan-08
1404    ---------------------
1406    1.  A character class containing a very large number of characters with
1407        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1408        overflow.
1410    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1411        HAVE_LONG_LONG is not defined.
1413    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1414        bring them up to date and include new features. This patch includes:
1416        - Fixed PH's badly added libz and libbz2 support.
1417        - Fixed a problem with static linking.
1418        - Added pcredemo. [But later removed - see 7 below.]
1419        - Fixed dftables problem and added an option.
1420        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1421            HAVE_LONG_LONG.
1422        - Added readline support for pcretest.
1423        - Added an listing of the option settings after cmake has run.
1425    4.  A user submitted a patch to Makefile that makes it easy to create
1426        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1427        Makefile.am that cause it to include this special target, without
1428        affecting anything else. Note that the same mingw target plus all
1429        the other distribution libraries and programs are now supported
1430        when configuring with CMake (see 6 below) instead of with
1431        Configure/Make.
1433    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1434        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1435        exported in the Windows port". It has not yet been confirmed that the patch
1436        solves the problem, but it does no harm.
1438    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1439        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1440        with CMake, and also correct the comment about stack recursion.
1442    7.  Remove the automatic building of pcredemo from the ./configure system and
1443        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1444        of a program that users should build themselves after PCRE is installed, so
1445        building it automatically is not really right. What is more, it gave
1446        trouble in some build environments.
1448    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1451    Version 7.5 10-Jan-08
1452    ---------------------
1454    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1455        values in parens when parsing an RE using the C++ wrapper."
1457    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1458        Characters greater than 255 were excluded from the class instead of being
1459        included.
1461    3.  The same bug as (2) above applied to negated POSIX classes such as
1462        [:^space:].
1464    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1465        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1466        I have changed it.
1468    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1469        first named subpattern) and a construct such as (?&a) would reference the
1470        first named subpattern whose name started with "a" (in other words, the
1471        length check was missing). Both these problems are fixed. "Subpattern name
1472        expected" is now given for (?&) (a zero-length name), and this patch also
1473        makes it give the same error for \k'' (previously it complained that that
1474        was a reference to a non-existent subpattern).
1476    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1477        this is right because (?- can be followed by option settings as well as by
1478        digits. I have, however, made the messages clearer.
1480    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1481        than the number used in the conditional) now cause a compile-time error.
1482        This is actually not compatible with Perl, which accepts such patterns, but
1483        treats the conditional as always being FALSE (as PCRE used to), but it
1484        seems to me that giving a diagnostic is better.
1486    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1487        and messages.
1489    9.  Fix two occurrences of "backslash" in comments that should have been
1490        "backspace".
1492    10. Remove two redundant lines of code that can never be obeyed (their function
1493        was moved elsewhere).
1495    11. The program that makes PCRE's Unicode character property table had a bug
1496        which caused it to generate incorrect table entries for sequences of
1497        characters that have the same character type, but are in different scripts.
1498        It amalgamated them into a single range, with the script of the first of
1499        them. In other words, some characters were in the wrong script. There were
1500        thirteen such cases, affecting characters in the following ranges:
1502          U+002b0 - U+002c1
1503          U+0060c - U+0060d
1504          U+0061e - U+00612
1505          U+0064b - U+0065e
1506          U+0074d - U+0076d
1507          U+01800 - U+01805
1508          U+01d00 - U+01d77
1509          U+01d9b - U+01dbf
1510          U+0200b - U+0200f
1511          U+030fc - U+030fe
1512          U+03260 - U+0327f
1513          U+0fb46 - U+0fbb1
1514          U+10450 - U+1049d
1516    12. The -o option (show only the matching part of a line) for pcregrep was not
1517        compatible with GNU grep in that, if there was more than one match in a
1518        line, it showed only the first of them. It now behaves in the same way as
1519        GNU grep.
1521    13. If the -o and -v options were combined for pcregrep, it printed a blank
1522        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1523        does the same. The return code can be used to tell if there were any
1524        non-matching lines.
1526    14. Added --file-offsets and --line-offsets to pcregrep.
1528    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1529        infinitely looping recursion. The bug was that positive lookaheads were not
1530        being skipped when checking for a possible empty match (negative lookaheads
1531        and both kinds of lookbehind were skipped).
1533    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1534        inclusion of <windows.h> to before rather than after the definition of
1535        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1537    17. Specifying a possessive quantifier with a specific limit for a Unicode
1538        character property caused pcre_compile() to compile bad code, which led at
1539        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1540        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1541        caused the error; without that there was no problem.
1543    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1545    19. Added --enable-pcretest-libreadline.
1547    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1548        RE::GlobalReplace(). As a result, the number of replacements returned was
1549        double what it should be. I removed one of the increments, but Craig sent a
1550        later patch that removed the other one (the right fix) and added unit tests
1551        that check the return values (which was not done before).
1553    21. Several CMake things:
1555        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1556            the names libpcre and libpcreposix, not just pcre and pcreposix.
1558        (2) The above change means that pcretest and pcregrep are now correctly
1559            linked with the newly-built libraries, not previously installed ones.
1563    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1564        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1565        UTF-8 newline character). The key issue is that the pattern starts .*;
1566        this means that the match must be either at the beginning, or after a
1567        newline. The bug was in the code for advancing after a failed match and
1568        checking that the new position followed a newline. It was not taking
1569        account of UTF-8 characters correctly.
1571    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1572        character classes. PCRE was not treating the sequence [:...:] as a
1573        character class unless the ... were all letters. Perl, however, seems to
1574        allow any characters between [: and :], though of course it rejects as
1575        unknown any "names" that contain non-letters, because all the known class
1576        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1577        for example, whereas PCRE did not - it did not recognize a POSIX character
1578        class. This seemed a bit dangerous, so the code has been changed to be
1579        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1580        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1581        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1582        Perl does, and where it didn't before.
1584    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1585        Windows environments %n is disabled by default.
1588    Version 7.4 21-Sep-07
1589    ---------------------
1591    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1592        means that a class such as [\s] counted as "explicit reference to CR or
1593        LF". That isn't really right - the whole point of the change was to try to
1594        help when there was an actual mention of one of the two characters. So now
1595        the change happens only if \r or \n (or a literal CR or LF) character is
1596        encountered.
1598    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1599        of both had grown to the point where there were only 3 bits left.
1600        Fortunately, there was spare space in the data structure, and so I have
1601        moved the internal flags into a new 16-bit field to free up more option
1602        bits.
1604    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1605        but did not set the internal JCHANGED flag - either of these is enough to
1606        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1607        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1608        start sets both bits.
1610    4.  Added options (at build time, compile time, exec time) to change \R from
1611        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1613    5.  doc/pcresyntax.html was missing from the distribution.
1615    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1616        compatibility, even though it is no longer used.
1618    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1619        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1620        windows.h file is present (where different names are used). [This was
1621        reversed later after testing - see 16 below.]
1623    8.  Changed all #include <config.h> to #include "config.h". There were also
1624        some further <pcre.h> cases that I changed to "pcre.h".
1626    9.  When pcregrep was used with the --colour option, it missed the line ending
1627        sequence off the lines that it output.
1629    10. It was pointed out to me that arrays of string pointers cause lots of
1630        relocations when a shared library is dynamically loaded. A technique of
1631        using a single long string with a table of offsets can drastically reduce
1632        these. I have refactored PCRE in four places to do this. The result is
1633        dramatic:
1635          Originally:                          290
1636          After changing UCP table:            187
1637          After changing error message table:   43
1638          After changing table of "verbs"       36
1639          After changing table of Posix names   22
1641        Thanks to the folks working on Gregex for glib for this insight.
1643    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1644        unicode-properties was also set.
1646    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1648    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1649        checked only for CRLF.
1651    14. Added casts to pcretest.c to avoid compiler warnings.
1653    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1655    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1656        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1657        entirely. This removes changes made in 7 above.
1659    17. The CMake files have been updated, and there is now more information about
1660        building with CMake in the NON-UNIX-USE document.
1663    Version 7.3 28-Aug-07
1664    ---------------------
1666     1. In the rejigging of the build system that eventually resulted in 7.1, the
1667        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1668        brackets there is not right, since it causes compilers to look for an
1669        installed pcre.h, not the version that is in the source that is being
1670        compiled (which of course may be different). I have changed it back to:
1672          #include "pcre.h"
1674        I have a vague recollection that the change was concerned with compiling in
1675        different directories, but in the new build system, that is taken care of
1676        by the VPATH setting the Makefile.
1678     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1679        when the subject happened to end in the byte 0x85 (e.g. if the last
1680        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1681        characters but of course it shouldn't be taken as a newline when it is part
1682        of another character. The bug was that, for an unlimited repeat of . in
1683        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1684        characters when looking for a newline.
1686     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1688     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1689        in debug output.
1691     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1692        long printing in the pcrecpp unittest when running under MinGW.
1694     6. ESC_K was left out of the EBCDIC table.
1696     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1697        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1698        limit also applies to "virtual nesting" when a pattern is recursive, and in
1699        this case 1000 isn't so big. I have been able to remove this limit at the
1700        expense of backing off one optimization in certain circumstances. Normally,
1701        when pcre_exec() would call its internal match() function recursively and
1702        immediately return the result unconditionally, it uses a "tail recursion"
1703        feature to save stack. However, when a subpattern that can match an empty
1704        string has an unlimited repetition quantifier, it no longer makes this
1705        optimization. That gives it a stack frame in which to save the data for
1706        checking that an empty string has been matched. Previously this was taken
1707        from the 1000-entry workspace that had been reserved. So now there is no
1708        explicit limit, but more stack is used.
1710     8. Applied Daniel's patches to solve problems with the import/export magic
1711        syntax that is required for Windows, and which was going wrong for the
1712        pcreposix and pcrecpp parts of the library. These were overlooked when this
1713        problem was solved for the main library.
1715     9. There were some crude static tests to avoid integer overflow when computing
1716        the size of patterns that contain repeated groups with explicit upper
1717        limits. As the maximum quantifier is 65535, the maximum group length was
1718        set at 30,000 so that the product of these two numbers did not overflow a
1719        32-bit integer. However, it turns out that people want to use groups that
1720        are longer than 30,000 bytes (though not repeat them that many times).
1721        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1722        made it possible to implement the integer overflow checks in a much more
1723        dynamic way, which I have now done. The artificial limitation on group
1724        length has been removed - we now have only the limit on the total length of
1725        the compiled pattern, which depends on the LINK_SIZE setting.
1727    10. Fixed a bug in the documentation for get/copy named substring when
1728        duplicate names are permitted. If none of the named substrings are set, the
1729        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1730        empty string.
1732    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1733        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1734        because the ] is interpreted as the first data character and the
1735        terminating ] is not found. PCRE has been made compatible with Perl in this
1736        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1737        cause memory overwriting.
1739    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1740        string has been matched (to stop an infinite loop). It was not recognizing
1741        a conditional subpattern that could match an empty string if that
1742        subpattern was within another subpattern. For example, it looped when
1743        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1744        condition was not nested. This bug has been fixed.
1746    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1747        past the start of the subject in the presence of bytes with the top bit
1748        set, for example "\x8aBCD".
1750    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1751        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1753    14. Optimized (?!) to (*FAIL).
1755    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1756        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1757        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1758        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1759        does: it's just the validity check that is more restrictive.
1761    16. Inserted checks for integer overflows during escape sequence (backslash)
1762        processing, and also fixed erroneous offset values for syntax errors during
1763        backslash processing.
1765    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1766        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1768    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1769        caused an overrun.
1771    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1772        something other than just ASCII characters) inside a group that had an
1773        unlimited repeat caused a loop at compile time (while checking to see
1774        whether the group could match an empty string).
1776    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1777        [\P{Any}] did so. (Error in the code for printing property names.)
1779    21. An orphan \E inside a character class could cause a crash.
1781    22. A repeated capturing bracket such as (A)? could cause a wild memory
1782        reference during compilation.
1784    23. There are several functions in pcre_compile() that scan along a compiled
1785        expression for various reasons (e.g. to see if it's fixed length for look
1786        behind). There were bugs in these functions when a repeated \p or \P was
1787        present in the pattern. These operators have additional parameters compared
1788        with \d, etc, and these were not being taken into account when moving along
1789        the compiled data. Specifically:
1791        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1792            length.
1794        (b) An item such as \pL+ within a repeated group could cause crashes or
1795            loops.
1797        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1798            "reference to non-existent subpattern" error.
1800        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1802    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1803        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1805    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1807    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1808        character were causing crashes (broken optimization).
1810    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1811        \p or \P) caused a compile-time loop.
1813    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1814        break. For example, the unstudied pattern [\r\n]A does not match the string
1815        "\r\nA" because change 7.0/46 below moves the current point on by two
1816        characters after failing to match at the start. However, the pattern \nA
1817        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1818        the same is true. There doesn't seem any very clean way out of this, but
1819        what I have chosen to do makes the common cases work: PCRE now takes note
1820        of whether there can be an explicit match for \r or \n anywhere in the
1821        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1822        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1823        pattern has explicit CR or LF references.
1825    29. Added (*CR) etc for changing newline setting at start of pattern.
1828    Version 7.2 19-Jun-07
1829    ---------------------
1831     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1832        which is apparently normally available under Windows.
1834     2. Re-jig the pcregrep tests with different newline settings in an attempt
1835        to make them independent of the local environment's newline setting.
1837     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1839     4. Some of the "internals" tests were previously cut out when the link size
1840        was not 2, because the output contained actual offsets. The recent new
1841        "Z" feature of pcretest means that these can be cut out, making the tests
1842        usable with all link sizes.
1844     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1845        stack recursion. This gives a massive performance boost under BSD, but just
1846        a small improvement under Linux. However, it saves one field in the frame
1847        in all cases.
1849     6. Added more features from the forthcoming Perl 5.10:
1851        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1852            recursion call. It refers to the nth most recently opened parentheses.
1854        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1855            to be opened parentheses.
1857        (c) Conditions that refer to capturing parentheses can be specified
1858            relatively, for example, (?(-2)... or (?(+3)...
1860        (d) \K resets the start of the current match so that everything before
1861            is not part of it.
1863        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1865        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1866            reference syntax.
1868        (g) (?| introduces a group in which the numbering of parentheses in each
1869            alternative starts with the same number.
1871        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1873     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1876     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1877        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1878        for detecting groups that can match an empty string.
1880     9. A pattern with a very large number of alternatives (more than several
1881        hundred) was running out of internal workspace during the pre-compile
1882        phase, where pcre_compile() figures out how much memory will be needed. A
1883        bit of new cunning has reduced the workspace needed for groups with
1884        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1885        workspace instead of running out of the 4096 that are available.
1887    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1889    11. Applied patch from Google to remove an optimization that didn't quite work.
1890        The report of the bug said:
1892          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1893          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1894          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1896    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1897        it matched the wrong number of bytes.
1900    Version 7.1 24-Apr-07
1901  ---------------------  ---------------------
1903   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 26  Version 7.1 12-Mar-07 Line 1922  Version 7.1 12-Mar-07
1922      .br or .in.      .br or .in.
1924   4. Updated comments in configure.ac that get placed in config.h.in and also   4. Updated comments in configure.ac that get placed in config.h.in and also
1925      arranged for config.h to be included in the distribution, with the name      arranged for config.h to be included in the distribution, with the name
1926      config.h.generic, for the benefit of those who have to compile without      config.h.generic, for the benefit of those who have to compile without
1927      Autotools (compare pcre.h, which is now distributed as pcre.h.generic).      Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1929   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1930      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1931      makevp.bat for the current PCRE, using the additional files !compile.txt,      makevp.bat for the current PCRE, using the additional files
1932      !linklib.txt, and pcregexp.pas.      makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1934   6. A Windows user reported a minor discrepancy with test 2, which turned out   6. A Windows user reported a minor discrepancy with test 2, which turned out
1935      to be caused by a trailing space on an input line that had got lost in his      to be caused by a trailing space on an input line that had got lost in his
# Line 63  Version 7.1 12-Mar-07 Line 1959  Version 7.1 12-Mar-07
1959  10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:  10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1961      (a) It was defining its arguments as char * instead of void *.      (a) It was defining its arguments as char * instead of void *.
1963      (b) It was assuming that all moves were upwards in memory; this was true      (b) It was assuming that all moves were upwards in memory; this was true
1964          a long time ago when I wrote it, but is no longer the case.          a long time ago when I wrote it, but is no longer the case.
1966      The emulated memove() is provided for those environments that have neither      The emulated memove() is provided for those environments that have neither
1967      memmove() nor bcopy(). I didn't think anyone used it these days, but that      memmove() nor bcopy(). I didn't think anyone used it these days, but that
1968      is clearly not the case, as these two bugs were recently reported.      is clearly not the case, as these two bugs were recently reported.
1970  11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,  11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1971      and Detrail to create the HTML documentation, the .txt form of the man      and Detrail to create the HTML documentation, the .txt form of the man
1972      pages, and it removes trailing spaces from listed files. It also creates      pages, and it removes trailing spaces from listed files. It also creates
1973      pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter      pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1974      case, it wraps all the #defines with #ifndefs. This script should be run      case, it wraps all the #defines with #ifndefs. This script should be run
1975      before "make dist".      before "make dist".
1977  12. Fixed two fairly obscure bugs concerned with quantified caseless matching  12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1978      with Unicode property support.      with Unicode property support.
1980      (a) For a maximizing quantifier, if the two different cases of the      (a) For a maximizing quantifier, if the two different cases of the
1981          character were of different lengths in their UTF-8 codings (there are          character were of different lengths in their UTF-8 codings (there are
1982          some cases like this - I found 11), and the matching function had to          some cases like this - I found 11), and the matching function had to
1983          back up over a mixture of the two cases, it incorrectly assumed they          back up over a mixture of the two cases, it incorrectly assumed they
1984          were both the same length.          were both the same length.
1986      (b) When PCRE was configured to use the heap rather than the stack for      (b) When PCRE was configured to use the heap rather than the stack for
1987          recursion during matching, it was not correctly preserving the data for          recursion during matching, it was not correctly preserving the data for
1988          the other case of a UTF-8 character when checking ahead for a match          the other case of a UTF-8 character when checking ahead for a match
1989          while processing a minimizing repeat. If the check also involved          while processing a minimizing repeat. If the check also involved
1990          matching a wide character, but failed, corruption could cause an          matching a wide character, but failed, corruption could cause an
1991          erroneous result when trying to check for a repeat of the original          erroneous result when trying to check for a repeat of the original
1992          character.          character.
1994  13. Some tidying changes to the testing mechanism:  13. Some tidying changes to the testing mechanism:
1996      (a) The RunTest script now detects the internal link size and whether there      (a) The RunTest script now detects the internal link size and whether there
1997          is UTF-8 and UCP support by running ./pcretest -C instead of relying on          is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1998          values substituted by "configure". (The RunGrepTest script already did          values substituted by "configure". (The RunGrepTest script already did
1999          this for UTF-8.) The configure.ac script no longer substitutes the          this for UTF-8.) The configure.ac script no longer substitutes the
2000          relevant variables.          relevant variables.
2002      (b) The debugging options /B and /D in pcretest show the compiled bytecode      (b) The debugging options /B and /D in pcretest show the compiled bytecode
2003          with length and offset values. This means that the output is different          with length and offset values. This means that the output is different
2004          for different internal link sizes. Test 2 is skipped for link sizes          for different internal link sizes. Test 2 is skipped for link sizes
2005          other than 2 because of this, bypassing the problem. Unfortunately,          other than 2 because of this, bypassing the problem. Unfortunately,
2006          there was also a test in test 3 (the locale tests) that used /B and          there was also a test in test 3 (the locale tests) that used /B and
2007          failed for link sizes other than 2. Rather than cut the whole test out,          failed for link sizes other than 2. Rather than cut the whole test out,
2008          I have added a new /Z option to pcretest that replaces the length and          I have added a new /Z option to pcretest that replaces the length and
2009          offset values with spaces. This is now used to make test 3 independent          offset values with spaces. This is now used to make test 3 independent
2010          of link size. (Test 2 will be tidied up later.)          of link size. (Test 2 will be tidied up later.)
2012  14. If erroroffset was passed as NULL to pcre_compile, it provoked a  14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2013      segmentation fault instead of returning the appropriate error message.      segmentation fault instead of returning the appropriate error message.
2015    15. In multiline mode when the newline sequence was set to "any", the pattern
2016        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2017        This doesn't seem right; it now treats the CRLF combination as the line
2018        ending, and so does not match in that case. It's only a pattern such as ^$
2019        that would hit this one: something like ^ABC$ would have failed after \r
2020        and then tried again after \r\n.
2022    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2023        in an attempt to make files that differ only in their line terminators
2024        compare equal. This works on Linux.
2026    17. Under certain error circumstances pcregrep might try to free random memory
2027        as it exited. This is now fixed, thanks to valgrind.
2029    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2030        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2031        was because its rules for how to advance for /g after matching an empty
2032        string at the end of a line did not allow for this case. They now check for
2033        it specially.
2035    20. pcretest is supposed to handle patterns and data of any length, by
2036        extending its buffers when necessary. It was getting this wrong when the
2037        buffer for a data line had to be extended.
2039    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2040        CRLF as a newline sequence.
2042    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2043        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2044        I have nevertheless tidied it up.
2046    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2048    24. Added a man page for pcre-config.
2051  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
2052  ---------------------  ---------------------

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