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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.31
5    -----------------------------
7    1.  Fixing a wrong JIT test case and some compiler warnings.
9    2.  Removed a bashism from the RunTest script.
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
45    9.  (*MARK) control verb is now supported by the JIT compiler.
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
51    Version 8.30 04-February-2012
52    -----------------------------
54    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
55        name is defined in ctype.h.
57    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
58        only in quite long subpatterns.
60    3.  Removed the function pcre_info(), which has been obsolete and deprecated
61        since it was replaced by pcre_fullinfo() in February 2000.
63    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
64        match a (*MARK), and the match failed at the start of the subject, a
65        reference to memory before the start of the subject could occur. This bug
66        was introduced by fix 17 of release 8.21.
68    5.  A reference to an unset group with zero minimum repetition was giving
69        totally wrong answers (in non-JavaScript-compatibility mode). For example,
70        /(another)?(\1?)test/ matched against "hello world test". This bug was
71        introduced in release 8.13.
73    6.  Add support for 16-bit character strings (a large amount of work involving
74        many changes and refactorings).
76    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
77        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
78        from a file.
80    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
81        rounding is not applied in this particular case).
83    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
84        if they appear, or are escaped, in patterns.
86    10. Get rid of a number of -Wunused-but-set-variable warnings.
88    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
89        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
90        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
91        also returns the mark "x". This bug applied to capturing parentheses,
92        non-capturing parentheses, and atomic parentheses. It also applied to some
93        assertions.
95    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
96        information out of configure.ac instead of relying on pcre.h.generic, which
97        is not stored in the repository.
99    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
100        -lreadline.
102    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
104    15. Applied Graycode's patch to put the top-level frame on the stack rather
105        than the heap when not using the stack for recursion. This gives a
106        performance improvement in many cases when recursion is not deep.
108    16. Experimental code added to "pcretest -C" to output the stack frame size.
111    Version 8.21 12-Dec-2011
112    ------------------------
114    1.  Updating the JIT compiler.
116    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
117        are added as well.
119    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
120        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
121        calling _pcre_jit_exec. Some extra comments are added.
123    4.  (*MARK) settings inside atomic groups that do not contain any capturing
124        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
125        was introduced by change 18 for 8.20.
127    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
128        ECMA-262 standard.
130    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
131        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
132        This bug was probably introduced by change 9 of 8.13.
134    7.  While fixing 6 above, I noticed that a number of other items were being
135        incorrectly rejected as "not fixed length". This arose partly because newer
136        opcodes had not been added to the fixed-length checking code. I have (a)
137        corrected the bug and added tests for these items, and (b) arranged for an
138        error to occur if an unknown opcode is encountered while checking for fixed
139        length instead of just assuming "not fixed length". The items that were
140        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
141        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
142        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
144    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
145        being incorrectly compiled and would have given unpredicatble results.
147    9.  A possessively repeated subpattern with minimum repeat count greater than
148        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
149        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
150        the first (A) could occur when it should not.
152    10. Add a cast and remove a redundant test from the code.
154    11. JIT should use pcre_malloc/pcre_free for allocation.
156    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
157        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
158        is anything other than /usr, -L is still shown).
160    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
162    14. Perl does not support \N without a following name in a [] class; PCRE now
163        also gives an error.
165    15. If a forward reference was repeated with an upper limit of around 2000,
166        it caused the error "internal error: overran compiling workspace". The
167        maximum number of forward references (including repeats) was limited by the
168        internal workspace, and dependent on the LINK_SIZE. The code has been
169        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
170        the default depends on LINK_SIZE. There is a new upper limit (for safety)
171        of around 200,000 forward references. While doing this, I also speeded up
172        the filling in of repeated forward references.
174    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
175        incorrectly expecting the subject to contain another "a" after the start.
177    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
178        in the match, the SKIP should be ignored. This was not happening; instead
179        the SKIP was being treated as NOMATCH. For patterns such as
180        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
181        tested.
183    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
184        now much more compatible with Perl, in particular in cases where the result
185        is a non-match for a non-anchored pattern. For example, if
186        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
187        "m", where previously it did not return a name. A side effect of this
188        change is that for partial matches, the last encountered mark name is
189        returned, as for non matches. A number of tests that were previously not
190        Perl-compatible have been moved into the Perl-compatible test files. The
191        refactoring has had the pleasing side effect of removing one argument from
192        the match() function, thus reducing its stack requirements.
194    19. If the /S+ option was used in pcretest to study a pattern using JIT,
195        subsequent uses of /S (without +) incorrectly behaved like /S+.
197    21. Retrieve executable code size support for the JIT compiler and fixing
198        some warnings.
200    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
201        not work when the shorter character appeared right at the end of the
202        subject string.
204    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
205        systems.
207    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
208        output it when the /M option is used in pcretest.
210    25. The CheckMan script was not being included in the distribution. Also, added
211        an explicit "perl" to run Perl scripts from the PrepareRelease script
212        because this is reportedly needed in Windows.
214    26. If study data was being save in a file and studying had not found a set of
215        "starts with" bytes for the pattern, the data written to the file (though
216        never used) was taken from uninitialized memory and so caused valgrind to
217        complain.
219    27. Updated RunTest.bat as provided by Sheri Pierce.
221    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
223    29. Computation of memory usage for the table of capturing group names was
224        giving an unnecessarily large value.
227    Version 8.20 21-Oct-2011
228    ------------------------
230    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
231        a POSIX class. After further experiments with Perl, which convinced me that
232        Perl has bugs and confusions, a closing square bracket is no longer allowed
233        in a POSIX name. This bug also affected patterns with classes that started
234        with full stops.
236    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
237        captured substring, but while checking the failing first alternative,
238        substring 1 is temporarily captured. If the output vector supplied to
239        pcre_exec() was not big enough for this capture, the yield of the function
240        was still zero ("insufficient space for captured substrings"). This cannot
241        be totally fixed without adding another stack variable, which seems a lot
242        of expense for a edge case. However, I have improved the situation in cases
243        such as /(a)(b)x|abc/ matched against "abc", where the return code
244        indicates that fewer than the maximum number of slots in the ovector have
245        been set.
247    3.  Related to (2) above: when there are more back references in a pattern than
248        slots in the output vector, pcre_exec() uses temporary memory during
249        matching, and copies in the captures as far as possible afterwards. It was
250        using the entire output vector, but this conflicts with the specification
251        that only 2/3 is used for passing back captured substrings. Now it uses
252        only the first 2/3, for compatibility. This is, of course, another edge
253        case.
255    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
256        main code base, and can be used by building with --enable-jit. When this is
257        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
258        runtime --no-jit option is given.
260    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
261        ovector, the return from the function was zero, implying that there were
262        other matches that did not fit. The correct "exactly full" value is now
263        returned.
265    6.  If a subpattern that was called recursively or as a subroutine contained
266        (*PRUNE) or any other control that caused it to give a non-standard return,
267        invalid errors such as "Error -26 (nested recursion at the same subject
268        position)" or even infinite loops could occur.
270    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
271        computing the minimum length on reaching *ACCEPT, and so ended up with the
272        wrong value of 1 rather than 0. Further investigation indicates that
273        computing a minimum subject length in the presence of *ACCEPT is difficult
274        (think back references, subroutine calls), and so I have changed the code
275        so that no minimum is registered for a pattern that contains *ACCEPT.
277    8.  If (*THEN) was present in the first (true) branch of a conditional group,
278        it was not handled as intended. [But see 16 below.]
280    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
281        Sheri Pierce.
283    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
284        the first byte in a match must be "a".
286    11. Change 17 for 8.13 increased the recursion depth for patterns like
287        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
288        pattern contains any instances of (*THEN). If it does not, the old
289        optimizations are restored. It would be nice to do this on a per-group
290        basis, but at the moment that is not feasible.
292    12. In some environments, the output of pcretest -C is CRLF terminated. This
293        broke RunTest's code that checks for the link size. A single white space
294        character after the value is now allowed for.
296    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
297        For "fr", it uses the Windows-specific input and output files.
299    14. If (*THEN) appeared in a group that was called recursively or as a
300        subroutine, it did not work as intended. [But see next item.]
302    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
303        pattern fragments (but not containing any | characters). If A and B are
304        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
305        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
306        D. In other words, Perl considers parentheses that do not contain any |
307        characters to be part of a surrounding alternative, whereas PCRE was
308        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
309        differently. PCRE now behaves in the same way as Perl, except in the case
310        of subroutine/recursion calls such as (?1) which have in any case always
311        been different (but PCRE had them first :-).
313    16. Related to 15 above: Perl does not treat the | in a conditional group as
314        creating alternatives. Such a group is treated in the same way as an
315        ordinary group without any | characters when processing (*THEN). PCRE has
316        been changed to match Perl's behaviour.
318    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
319        RunGrepTest script failed.
321    18. Change 22 for version 13 caused atomic groups to use more stack. This is
322        inevitable for groups that contain captures, but it can lead to a lot of
323        stack use in large patterns. The old behaviour has been restored for atomic
324        groups that do not contain any capturing parentheses.
326    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
327        suppress the check for a minimum subject length at run time. (If it was
328        given to pcre_exec() or pcre_dfa_exec() it did work.)
330    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
331        fail to work when decoding hex characters in data strings in EBCDIC
332        environments.
334    21. It appears that in at least one Mac OS environment, the isxdigit() function
335        is implemented as a macro that evaluates to its argument more than once,
336        contravening the C 90 Standard (I haven't checked a later standard). There
337        was an instance in pcretest which caused it to go wrong when processing
338        \x{...} escapes in subject strings. The has been rewritten to avoid using
339        things like p++ in the argument of isxdigit().
342    Version 8.13 16-Aug-2011
343    ------------------------
345    1.  The Unicode data tables have been updated to Unicode 6.0.0.
347    2.  Two minor typos in pcre_internal.h have been fixed.
349    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
350        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
351        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
353    4.  There were a number of related bugs in the code for matching backrefences
354        caselessly in UTF-8 mode when codes for the characters concerned were
355        different numbers of bytes. For example, U+023A and U+2C65 are an upper
356        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
357        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
358        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
359        2-byte code at the end of the subject (it thought there wasn't enough data
360        left).
362    5.  Comprehensive information about what went wrong is now returned by
363        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
364        as the output vector has at least 2 elements. The offset of the start of
365        the failing character and a reason code are placed in the vector.
367    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
368        now returned is for the first byte of the failing character, instead of the
369        last byte inspected. This is an incompatible change, but I hope it is small
370        enough not to be a problem. It makes the returned offset consistent with
371        pcre_exec() and pcre_dfa_exec().
373    7.  pcretest now gives a text phrase as well as the error number when
374        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
375        failure, the offset and reason code are output.
377    8.  When \R was used with a maximizing quantifier it failed to skip backwards
378        over a \r\n pair if the subsequent match failed. Instead, it just skipped
379        back over a single character (\n). This seems wrong (because it treated the
380        two characters as a single entity when going forwards), conflicts with the
381        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
382        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
383        has been changed.
385    9.  Some internal refactoring has changed the processing so that the handling
386        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
387        time (the PCRE_DOTALL option was changed this way some time ago: version
388        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
389        which was always a bit of a fudge. It also means that there is one less
390        argument for the match() function, which reduces its stack requirements
391        slightly. This change also fixes an incompatibility with Perl: the pattern
392        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
394    10. More internal refactoring has drastically reduced the number of recursive
395        calls to match() for possessively repeated groups such as (abc)++ when
396        using pcre_exec().
398    11. While implementing 10, a number of bugs in the handling of groups were
399        discovered and fixed:
401        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
402        (a|)*(?1) gave a compile-time internal error.
403        ((a|)+)+  did not notice that the outer group could match an empty string.
404        (^a|^)+   was not marked as anchored.
405        (.*a|.*)+ was not marked as matching at start or after a newline.
407    12. Yet more internal refactoring has removed another argument from the match()
408        function. Special calls to this function are now indicated by setting a
409        value in a variable in the "match data" data block.
411    13. Be more explicit in pcre_study() instead of relying on "default" for
412        opcodes that mean there is no starting character; this means that when new
413        ones are added and accidentally left out of pcre_study(), testing should
414        pick them up.
416    14. The -s option of pcretest has been documented for ages as being an old
417        synonym of -m (show memory usage). I have changed it to mean "force study
418        for every regex", that is, assume /S for every regex. This is similar to -i
419        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
420        using it. It makes it easier to run collections of tests with and without
421        study enabled, and thereby test pcre_study() more easily. All the standard
422        tests are now run with and without -s (but some patterns can be marked as
423        "never study" - see 20 below).
425    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
426        restoration of the capturing data to the outer values was not happening
427        correctly.
429    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
430        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
431        pattern had matched an empty string, and so incorrectly returned a no
432        match.
434    17. There was optimizing code for the last branch of non-capturing parentheses,
435        and also for the obeyed branch of a conditional subexpression, which used
436        tail recursion to cut down on stack usage. Unfortunately, now that there is
437        the possibility of (*THEN) occurring in these branches, tail recursion is
438        no longer possible because the return has to be checked for (*THEN). These
439        two optimizations have therefore been removed. [But see 8.20/11 above.]
441    18. If a pattern containing \R was studied, it was assumed that \R always
442        matched two bytes, thus causing the minimum subject length to be
443        incorrectly computed because \R can also match just one byte.
445    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
446        was incorrectly computed.
448    20. If /S is present twice on a test pattern in pcretest input, it now
449        *disables* studying, thereby overriding the use of -s on the command line
450        (see 14 above). This is necessary for one or two tests to keep the output
451        identical in both cases.
453    21. When (*ACCEPT) was used in an assertion that matched an empty string and
454        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
456    22. When an atomic group that contained a capturing parenthesis was
457        successfully matched, but the branch in which it appeared failed, the
458        capturing was not being forgotten if a higher numbered group was later
459        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
460        group 1 to "a", when in fact it should be unset. This applied to multi-
461        branched capturing and non-capturing groups, repeated or not, and also to
462        positive assertions (capturing in negative assertions does not happen
463        in PCRE) and also to nested atomic groups.
465    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
466        subject after a captured substring, to make it easier to tell which of a
467        number of identical substrings has been captured.
469    24. The way atomic groups are processed by pcre_exec() has been changed so that
470        if they are repeated, backtracking one repetition now resets captured
471        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
472        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
473        "aaa". Previously, it would have been "a". As part of this code
474        refactoring, the way recursive calls are handled has also been changed.
476    25. If an assertion condition captured any substrings, they were not passed
477        back unless some other capturing happened later. For example, if
478        (?(?=(a))a) was matched against "a", no capturing was returned.
480    26. When studying a pattern that contained subroutine calls or assertions,
481        the code for finding the minimum length of a possible match was handling
482        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
483        group 1 called group 2 while simultaneously a separate group 2 called group
484        1). A stack overflow occurred in this case. I have fixed this by limiting
485        the recursion depth to 10.
487    27. Updated RunTest.bat in the distribution to the version supplied by Tom
488        Fortmann. This supports explicit test numbers on the command line, and has
489        argument validation and error reporting.
491    28. An instance of \X with an unlimited repeat could fail if at any point the
492        first character it looked at was a mark character.
494    29. Some minor code refactoring concerning Unicode properties and scripts
495        should reduce the stack requirement of match() slightly.
497    30. Added the '=' option to pcretest to check the setting of unused capturing
498        slots at the end of the pattern, which are documented as being -1, but are
499        not included in the return count.
501    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
502        compiled something random. Now it gives a compile-time error (as does
503        Perl).
505    32. A *MARK encountered during the processing of a positive assertion is now
506        recorded and passed back (compatible with Perl).
508    33. If --only-matching or --colour was set on a pcregrep call whose pattern
509        had alternative anchored branches, the search for a second match in a line
510        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
511        matched the line "0102" twice. The same bug affected patterns that started
512        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
513        twice.
515    34. Previously, PCRE did not allow quantification of assertions. However, Perl
516        does, and because of capturing effects, quantifying parenthesized
517        assertions may at times be useful. Quantifiers are now allowed for
518        parenthesized assertions.
520    35. A minor code tidy in pcre_compile() when checking options for \R usage.
522    36. \g was being checked for fancy things in a character class, when it should
523        just be a literal "g".
525    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
526        appearance of a nested POSIX class supersedes an apparent external class.
527        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
528        unescaped square brackets may also appear as part of class names. For
529        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
530        more like Perl. (But see 8.20/1 above.)
532    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
533        was because it thought it was \N{name}, which is not supported).
535    39. Add minix to OS list not supporting the -S option in pcretest.
537    40. PCRE tries to detect cases of infinite recursion at compile time, but it
538        cannot analyze patterns in sufficient detail to catch mutual recursions
539        such as ((?1))((?2)). There is now a runtime test that gives an error if a
540        subgroup is called recursively as a subpattern for a second time at the
541        same position in the subject string. In previous releases this might have
542        been caught by the recursion limit, or it might have run out of stack.
544    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
545        happen only once. PCRE was, however incorrectly giving a compile time error
546        "recursive call could loop indefinitely" because it cannot analyze the
547        pattern in sufficient detail. The compile time test no longer happens when
548        PCRE is compiling a conditional subpattern, but actual runaway loops are
549        now caught at runtime (see 40 above).
551    42. It seems that Perl allows any characters other than a closing parenthesis
552        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
553        has been changed to be the same.
555    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
556        as not to get warnings when autogen.sh is called. Also changed
557        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
559    44. To help people who use pcregrep to scan files containing exceedingly long
560        lines, the following changes have been made:
562        (a) The default value of the buffer size parameter has been increased from
563            8K to 20K. (The actual buffer used is three times this size.)
565        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
566            PCRE is built.
568        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
569            to be set at run time.
571        (d) Numerical values in pcregrep options can be followed by K or M, for
572            example --buffer-size=50K.
574        (e) If a line being scanned overflows pcregrep's buffer, an error is now
575            given and the return code is set to 2.
577    45. Add a pointer to the latest mark to the callout data block.
579    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
580        partial match of an empty string instead of no match. This was specific to
581        the use of ".".
583    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
584        complete match instead of a partial match. This bug was dependent on both
585        the PCRE_UTF8 and PCRE_DOTALL options being set.
587    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
588        starting byte set, because \b was not being ignored.
591    Version 8.12 15-Jan-2011
592    ------------------------
594    1.  Fixed some typos in the markup of the man pages, and wrote a script that
595        checks for such things as part of the documentation building process.
597    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
598        --match-limit and --recursion-limit options (added for 8.11). In
599        particular, this made one of the standard tests fail. (The integer value
600        went into the wrong half of a long int.)
602    3.  If the --colour option was given to pcregrep with -v (invert match), it
603        did strange things, either producing crazy output, or crashing. It should,
604        of course, ignore a request for colour when reporting lines that do not
605        match.
607    4.  Another pcregrep bug caused similar problems if --colour was specified with
608        -M (multiline) and the pattern match finished with a line ending.
610    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
611        matched in multiline mode, the following line was shown as part of the
612        match. This seems wrong, so I have changed it.
614    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
615        the check for further matches in the same line (so they could be coloured)
616        to overrun the end of the current line. If another match was found, it was
617        incorrectly shown (and then shown again when found in the next line).
619    7.  If pcregrep was compiled under Windows, there was a reference to the
620        function pcregrep_exit() before it was defined. I am assuming this was
621        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
622        reported by a user. I've moved the definition above the reference.
625    Version 8.11 10-Dec-2010
626    ------------------------
628    1.  (*THEN) was not working properly if there were untried alternatives prior
629        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
630        backtracked to try for "b" instead of moving to the next alternative branch
631        at the same level (in this case, to look for "c"). The Perl documentation
632        is clear that when (*THEN) is backtracked onto, it goes to the "next
633        alternative in the innermost enclosing group".
635    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
636        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
637        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
638        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
639        (*THEN).
641    3.  If \s appeared in a character class, it removed the VT character from
642        the class, even if it had been included by some previous item, for example
643        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
644        of \s, but is part of the POSIX "space" class.)
646    4.  A partial match never returns an empty string (because you can always
647        match an empty string at the end of the subject); however the checking for
648        an empty string was starting at the "start of match" point. This has been
649        changed to the "earliest inspected character" point, because the returned
650        data for a partial match starts at this character. This means that, for
651        example, /(?<=abc)def/ gives a partial match for the subject "abc"
652        (previously it gave "no match").
654    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
655        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
656        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
657        has an implication that the given string is incomplete (because a partial
658        match is preferred over a full match). For this reason, these items now
659        give a partial match in this situation. [Aside: previously, the one case
660        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
661        match rather than a full match, which was wrong by the old rules, but is
662        now correct.]
664    6.  There was a bug in the handling of #-introduced comments, recognized when
665        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
666        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
667        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
668        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
669        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
670        places in pcre_compile().
672    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
673        comments when looking ahead for named forward references to subpatterns,
674        the only newline sequence it recognized was NL. It now handles newlines
675        according to the set newline convention.
677    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
678        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
679        cater for a lack of strerror(). These oversights have been fixed.
681    9.  Added --match-limit and --recursion-limit to pcregrep.
683    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
685    11. When the -o option was used, pcregrep was setting a return code of 1, even
686        when matches were found, and --line-buffered was not being honoured.
688    12. Added an optional parentheses number to the -o and --only-matching options
689        of pcregrep.
691    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
692        can match an empty string. The code to do it in pcretest and pcredemo
693        needed fixing:
695        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
696            only one byte after an empty string match just before CRLF (this case
697            just got forgotten; "any" and "anycrlf" were OK).
699        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
700            mode when an empty string match preceded an ASCII character followed by
701            a non-ASCII character. (The code for advancing by one character rather
702            than one byte was nonsense.)
704        (c) The pcredemo.c sample program did not have any code at all to handle
705            the cases when CRLF is a valid newline sequence.
707    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
708        as a starting offset was within the subject string. There is now a new
709        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
710        negative or greater than the length of the string. In order to test this,
711        pcretest is extended to allow the setting of negative starting offsets.
713    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
714        starting offset points to the beginning of a UTF-8 character was
715        unnecessarily clumsy. I tidied it up.
717    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
718        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
720    17. Nobody had reported that the --include_dir option, which was added in
721        release 7.7 should have been called --include-dir (hyphen, not underscore)
722        for compatibility with GNU grep. I have changed it to --include-dir, but
723        left --include_dir as an undocumented synonym, and the same for
724        --exclude-dir, though that is not available in GNU grep, at least as of
725        release 2.5.4.
727    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
728        characters from a string of bytes) have been redefined so as not to use
729        loops, in order to improve performance in some environments. At the same
730        time, I abstracted some of the common code into auxiliary macros to save
731        repetition (this should not affect the compiled code).
733    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
734        compile-time error is now given if \c is not followed by an ASCII
735        character, that is, a byte less than 128. (In EBCDIC mode, the code is
736        different, and any byte value is allowed.)
738    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
739        START_OPTIMIZE option, which is now allowed at compile time - but just
740        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
741        to pcregrep and other applications that have no direct access to PCRE
742        options. The new /Y option in pcretest sets this option when calling
743        pcre_compile().
745    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
746        back references. Groups containing recursive back references were forced to
747        be atomic by that change, but in the case of named groups, the amount of
748        memory required was incorrectly computed, leading to "Failed: internal
749        error: code overflow". This has been fixed.
751    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
752        pcretest.c, to avoid build problems in some Borland environments.
755    Version 8.10 25-Jun-2010
756    ------------------------
758    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
759        THEN.
761    2.  (*ACCEPT) was not working when inside an atomic group.
763    3.  Inside a character class, \B is treated as a literal by default, but
764        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
765        causes the error). The code is unchanged, but I tidied the documentation.
767    4.  Inside a character class, PCRE always treated \R and \X as literals,
768        whereas Perl faults them if its -w option is set. I have changed PCRE so
769        that it faults them when PCRE_EXTRA is set.
771    5.  Added support for \N, which always matches any character other than
772        newline. (It is the same as "." when PCRE_DOTALL is not set.)
774    6.  When compiling pcregrep with newer versions of gcc which may have
775        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
776        declared with attribute warn_unused_result" were given. Just casting the
777        result to (void) does not stop the warnings; a more elaborate fudge is
778        needed. I've used a macro to implement this.
780    7.  Minor change to pcretest.c to avoid a compiler warning.
782    8.  Added four artifical Unicode properties to help with an option to make
783        \s etc use properties (see next item). The new properties are: Xan
784        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
786    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
787        use Unicode properties. (*UCP) at the start of a pattern can be used to set
788        this option. Modified pcretest to add /W to test this facility. Added
789        REG_UCP to make it available via the POSIX interface.
791    10. Added --line-buffered to pcregrep.
793    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
794        studied, and the match started with a letter with a code point greater than
795        127 whose first byte was different to the first byte of the other case of
796        the letter, the other case of this starting letter was not recognized
797        (#976).
799    12. If a pattern that was studied started with a repeated Unicode property
800        test, for example, \p{Nd}+, there was the theoretical possibility of
801        setting up an incorrect bitmap of starting bytes, but fortunately it could
802        not have actually happened in practice until change 8 above was made (it
803        added property types that matched character-matching opcodes).
805    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
806        possible starting bytes for non-anchored patterns.
808    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
809        \R, and also a number of cases that involve Unicode properties, both
810        explicit and implicit when PCRE_UCP is set.
812    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
813        input, it could crash or give wrong results if characters with values
814        greater than 0xc0 were present in the subject string. (Detail: it assumed
815        UTF-8 input when processing these items.)
817    16. Added a lot of (int) casts to avoid compiler warnings in systems where
818        size_t is 64-bit (#991).
820    17. Added a check for running out of memory when PCRE is compiled with
821        --disable-stack-for-recursion (#990).
823    18. If the last data line in a file for pcretest does not have a newline on
824        the end, a newline was missing in the output.
826    19. The default pcre_chartables.c file recognizes only ASCII characters (values
827        less than 128) in its various bitmaps. However, there is a facility for
828        generating tables according to the current locale when PCRE is compiled. It
829        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
830        characters, are recognized by isspace() and therefore were getting set in
831        these tables, and indeed these tables seem to approximate to ISO 8859. This
832        caused a problem in UTF-8 mode when pcre_study() was used to create a list
833        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
834        which of course cannot start UTF-8 characters. I have changed the code so
835        that only real ASCII characters (less than 128) and the correct starting
836        bytes for UTF-8 encodings are set for characters greater than 127 when in
837        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
838        altogether.)
840    20. Added the /T option to pcretest so as to be able to run tests with non-
841        standard character tables, thus making it possible to include the tests
842        used for 19 above in the standard set of tests.
844    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
845        reference to a subpattern the other side of a comment that contains an
846        opening parenthesis caused either an internal compiling error, or a
847        reference to the wrong subpattern.
850    Version 8.02 19-Mar-2010
851    ------------------------
853    1.  The Unicode data tables have been updated to Unicode 5.2.0.
855    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
856        configured.
858    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
859        original author of that file, following a query about its status.
861    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
862        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
864    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
865        quantifier applied to a forward-referencing subroutine call, could compile
866        incorrect code or give the error "internal error: previously-checked
867        referenced subpattern not found".
869    6.  Both MS Visual Studio and Symbian OS have problems with initializing
870        variables to point to external functions. For these systems, therefore,
871        pcre_malloc etc. are now initialized to local functions that call the
872        relevant global functions.
874    7.  There were two entries missing in the vectors called coptable and poptable
875        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
876        I've fixed the data, and added a kludgy way of testing at compile time that
877        the lengths are correct (equal to the number of opcodes).
879    8.  Following on from 7, I added a similar kludge to check the length of the
880        eint vector in pcreposix.c.
882    9.  Error texts for pcre_compile() are held as one long string to avoid too
883        much relocation at load time. To find a text, the string is searched,
884        counting zeros. There was no check for running off the end of the string,
885        which could happen if a new error number was added without updating the
886        string.
888    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
890    11. \K was not working if it appeared in an atomic group or in a group that
891        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
892        \K is "not well defined" if used in an assertion. PCRE now accepts it if
893        the assertion is positive, but not if it is negative.
895    12. Change 11 fortuitously reduced the size of the stack frame used in the
896        "match()" function of pcre_exec.c by one pointer. Forthcoming
897        implementation of support for (*MARK) will need an extra pointer on the
898        stack; I have reserved it now, so that the stack frame size does not
899        decrease.
901    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
902        item in branch that calls a recursion is a subroutine call - as in the
903        second branch in the above example - was incorrectly given the compile-
904        time error "recursive call could loop indefinitely" because pcre_compile()
905        was not correctly checking the subroutine for matching a non-empty string.
907    14. The checks for overrunning compiling workspace could trigger after an
908        overrun had occurred. This is a "should never occur" error, but it can be
909        triggered by pathological patterns such as hundreds of nested parentheses.
910        The checks now trigger 100 bytes before the end of the workspace.
912    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
915    Version 8.01 19-Jan-2010
916    ------------------------
918    1.  If a pattern contained a conditional subpattern with only one branch (in
919        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
920        computed the wrong minimum data length (which is of course zero for such
921        subpatterns). This could cause incorrect "no match" results.
923    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
924        the pattern is reset in the first branch, pcre_compile() failed with
925        "internal error: code overflow at offset...". This happened only when
926        the reset was to the original external option setting. (An optimization
927        abstracts leading options settings into an external setting, which was the
928        cause of this.)
930    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
931        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
932        assertion pattern did not match (meaning that the assertion was true), it
933        was incorrectly treated as false if the SKIP had been reached during the
934        matching. This also applied to assertions used as conditions.
936    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
937        assertion subpattern, including such a pattern used as a condition,
938        unpredictable results occurred, instead of the error return
941    5.  The C++ GlobalReplace function was not working like Perl for the special
942        situation when an empty string is matched. It now does the fancy magic
943        stuff that is necessary.
945    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
946        removed. (These were left over from very, very early versions of PCRE.)
948    7.  Some cosmetic changes to the code to make life easier when compiling it
949        as part of something else:
951        (a) Change DEBUG to PCRE_DEBUG.
953        (b) In pcre_compile(), rename the member of the "branch_chain" structure
954            called "current" as "current_branch", to prevent a collision with the
955            Linux macro when compiled as a kernel module.
957        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
958            prevent a collision with the Linux macro when compiled as a kernel
959            module.
961    8.  In pcre_compile() there are some checks for integer overflows that used to
962        cast potentially large values to (double). This has been changed to that
963        when building, a check for int64_t is made, and if it is found, it is used
964        instead, thus avoiding the use of floating point arithmetic. (There is no
965        other use of FP in PCRE.) If int64_t is not found, the fallback is to
966        double.
968    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
969        2005 (difference between two addresses compared to an unsigned value).
971    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
972        custom one, because of the following reported problem in Windows:
974          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
975              under Win32.
976          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
977              therefore missing the function definition.
978          - The compiler thus generates a "C" signature for the test function.
979          - The linker fails to find the "C" function.
980          - PCRE fails to configure if asked to do so against libbz2.
982    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
983        messages were output:
985          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
986          rerunning libtoolize, to keep the correct libtool macros in-tree.
987          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
989        I have done both of these things.
991    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
992        most of the time, it *can* run out if it is given a pattern that contains a
993        runaway infinite recursion. I updated the discussion in the pcrestack man
994        page.
996    13. Now that we have gone to the x.xx style of version numbers, the minor
997        version may start with zero. Using 08 or 09 is a bad idea because users
998        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
999        interpreted as invalid octal numbers. I've updated the previous comment in
1000        configure.ac, and also added a check that gives an error if 08 or 09 are
1001        used.
1003    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
1004        causing partial matching to fail when the end of the subject matched \W
1005        in a UTF-8 pattern where \W was quantified with a minimum of 3.
1007    15. There were some discrepancies between the declarations in pcre_internal.h
1008        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1009        their definitions. The declarations used "const uschar *" and the
1010        definitions used USPTR. Even though USPTR is normally defined as "const
1011        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1012        reported that: "This difference in casting confuses some C++ compilers, for
1013        example, SunCC recognizes above declarations as different functions and
1014        generates broken code for hbpcre." I have changed the declarations to use
1015        USPTR.
1017    16. GNU libtool is named differently on some systems. The autogen.sh script now
1018        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1019        (FreeBSD).
1021    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1022        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1023        comment: "Figure out how to create a longlong from a string: strtoll and
1024        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1025        instance, but it only takes 2 args instead of 3!"
1027    18. A subtle bug concerned with back references has been fixed by a change of
1028        specification, with a corresponding code fix. A pattern such as
1029        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1030        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1031        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1032        same bug. Such groups have to be quantified to be useful, or contained
1033        inside another quantified group. (If there's no repetition, the reference
1034        can never match.) The problem arises because, having left the group and
1035        moved on to the rest of the pattern, a later failure that backtracks into
1036        the group uses the captured value from the final iteration of the group
1037        rather than the correct earlier one. I have fixed this in PCRE by forcing
1038        any group that contains a reference to itself to be an atomic group; that
1039        is, there cannot be any backtracking into it once it has completed. This is
1040        similar to recursive and subroutine calls.
1043    Version 8.00 19-Oct-09
1044    ----------------------
1046    1.  The table for translating pcre_compile() error codes into POSIX error codes
1047        was out-of-date, and there was no check on the pcre_compile() error code
1048        being within the table. This could lead to an OK return being given in
1049        error.
1051    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1052        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1053        in a Windows environment.
1055    3.  The pcregrep --count option prints the count for each file even when it is
1056        zero, as does GNU grep. However, pcregrep was also printing all files when
1057        --files-with-matches was added. Now, when both options are given, it prints
1058        counts only for those files that have at least one match. (GNU grep just
1059        prints the file name in this circumstance, but including the count seems
1060        more useful - otherwise, why use --count?) Also ensured that the
1061        combination -clh just lists non-zero counts, with no names.
1063    4.  The long form of the pcregrep -F option was incorrectly implemented as
1064        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1065        but it seems right to fix it, and I didn't think it was worth preserving
1066        the old behaviour.
1068    5.  The command line items --regex=pattern and --regexp=pattern were not
1069        recognized by pcregrep, which required --regex pattern or --regexp pattern
1070        (with a space rather than an '='). The man page documented the '=' forms,
1071        which are compatible with GNU grep; these now work.
1073    6.  No libpcreposix.pc file was created for pkg-config; there was just
1074        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1076    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1077        when UCP support is not needed, by modifying the Python script that
1078        generates it from Unicode data files. This should not matter if the module
1079        is correctly used as a library, but I received one complaint about 50K of
1080        unwanted data. My guess is that the person linked everything into his
1081        program rather than using a library. Anyway, it does no harm.
1083    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1084        was a minimum greater than 1 for a wide character in a possessive
1085        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1086        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1087        character. Chaos in the form of incorrect output or a compiling loop could
1088        result.
1090    9.  The restrictions on what a pattern can contain when partial matching is
1091        requested for pcre_exec() have been removed. All patterns can now be
1092        partially matched by this function. In addition, if there are at least two
1093        slots in the offset vector, the offset of the earliest inspected character
1094        for the match and the offset of the end of the subject are set in them when
1095        PCRE_ERROR_PARTIAL is returned.
1097    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1098        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1099        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1100        and may be more useful for multi-segment matching.
1102    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1103        used to be given if ever the end of the subject was reached; now it is
1104        given only if matching could not proceed because another character was
1105        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1106        string "Z", which now yields "no match" instead of "partial match". In the
1107        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1108        final character ended with (*FAIL).
1110    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1111        if the pattern had a "must contain" character that was already found in the
1112        earlier partial match, unless partial matching was again requested. For
1113        example, with the pattern /dog.(body)?/, the "must contain" character is
1114        "g". If the first part-match was for the string "dog", restarting with
1115        "sbody" failed. This bug has been fixed.
1117    13. The string returned by pcre_dfa_exec() after a partial match has been
1118        changed so that it starts at the first inspected character rather than the
1119        first character of the match. This makes a difference only if the pattern
1120        starts with a lookbehind assertion or \b or \B (\K is not supported by
1121        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1122        matching functions compatible, and I think it's the right thing to do.
1124    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1125        so that the demonstration program is easily available in environments where
1126        PCRE has not been installed from source.
1128    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1129        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1130        library.
1132    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1133        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1134        is not the first non-POSIX option to be added. Clearly some people find
1135        these options useful.
1137    17. If a caller to the POSIX matching function regexec() passes a non-zero
1138        value for nmatch with a NULL value for pmatch, the value of
1139        nmatch is forced to zero.
1141    18. RunGrepTest did not have a test for the availability of the -u option of
1142        the diff command, as RunTest does. It now checks in the same way as
1143        RunTest, and also checks for the -b option.
1145    19. If an odd number of negated classes containing just a single character
1146        interposed, within parentheses, between a forward reference to a named
1147        subpattern and the definition of the subpattern, compilation crashed with
1148        an internal error, complaining that it could not find the referenced
1149        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1150        [The bug was that it was starting one character too far in when skipping
1151        over the character class, thus treating the ] as data rather than
1152        terminating the class. This meant it could skip too much.]
1154    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1155        /g option in pcretest when the pattern contains \K, which makes it possible
1156        to have an empty string match not at the start, even when the pattern is
1157        anchored. Updated pcretest and pcredemo to use this option.
1159    21. If the maximum number of capturing subpatterns in a recursion was greater
1160        than the maximum at the outer level, the higher number was returned, but
1161        with unset values at the outer level. The correct (outer level) value is
1162        now given.
1164    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1165        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1166        make it do so. The string so far is captured, making this feature
1167        compatible with Perl.
1169    23. The tests have been re-organized, adding tests 11 and 12, to make it
1170        possible to check the Perl 5.10 features against Perl 5.10.
1172    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1173        pattern matches a fixed length string. PCRE did not allow this; now it
1174        does. Neither allows recursion.
1176    25. I finally figured out how to implement a request to provide the minimum
1177        length of subject string that was needed in order to match a given pattern.
1178        (It was back references and recursion that I had previously got hung up
1179        on.) This code has now been added to pcre_study(); it finds a lower bound
1180        to the length of subject needed. It is not necessarily the greatest lower
1181        bound, but using it to avoid searching strings that are too short does give
1182        some useful speed-ups. The value is available to calling programs via
1183        pcre_fullinfo().
1185    26. While implementing 25, I discovered to my embarrassment that pcretest had
1186        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1187        study optimizations had never been tested with that matching function.
1188        Oops. What is worse, even when it was passed study data, there was a bug in
1189        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1190        were also very few tests of studied patterns with pcre_dfa_exec().
1192    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1193        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1194        on the other side of the coin, they are no longer allowed to have different
1195        names, because these cannot be distinguished in PCRE, and this has caused
1196        confusion. (This is a difference from Perl.)
1198    28. When duplicate subpattern names are present (necessarily with different
1199        numbers, as required by 27 above), and a test is made by name in a
1200        conditional pattern, either for a subpattern having been matched, or for
1201        recursion in such a pattern, all the associated numbered subpatterns are
1202        tested, and the overall condition is true if the condition is true for any
1203        one of them. This is the way Perl works, and is also more like the way
1204        testing by number works.
1207    Version 7.9 11-Apr-09
1208    ---------------------
1210    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1211        (pcretest), all targets were linked against these libraries. This included
1212        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1213        libraries. This caused unwanted dependencies to be created. This problem
1214        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1215        pcretest is linked with readline.
1217    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1218        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1219        moved outside it again, because FALSE and TRUE are already defined in AIX,
1220        but BOOL is not.
1222    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1223        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1225    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1226        hyphens) following file names and line numbers when outputting matching
1227        lines. This is not true; no spaces are inserted. I have also clarified the
1228        wording for the --colour (or --color) option.
1230    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1231        was not coloured; this is different to GNU grep, so I have changed it to be
1232        the same.
1234    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1235        each matching line was coloured. Now it goes on to look for further matches
1236        of any of the test patterns, which is the same behaviour as GNU grep.
1238    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1239        doesn't make sense to accept an empty string match in pcregrep, so I have
1240        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1241        seems to be how GNU grep behaves.
1243    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1244        start or after a newline", because the conditional assertion was not being
1245        correctly handled. The rule now is that both the assertion and what follows
1246        in the first alternative must satisfy the test.
1248    9.  If auto-callout was enabled in a pattern with a conditional group whose
1249        condition was an assertion, PCRE could crash during matching, both with
1250        pcre_exec() and pcre_dfa_exec().
1252    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1253        used for matching.
1255    11. Unicode property support in character classes was not working for
1256        characters (bytes) greater than 127 when not in UTF-8 mode.
1258    12. Added the -M command line option to pcretest.
1260    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1262    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1264    16. Added comments and documentation about mis-use of no_arg in the C++
1265        wrapper.
1267    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1268        from Martin Jerabek that uses macro names for all relevant character and
1269        string constants.
1271    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1272        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1273        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1274        these, but not everybody uses configure.
1276    19. A conditional group that had only one branch was not being correctly
1277        recognized as an item that could match an empty string. This meant that an
1278        enclosing group might also not be so recognized, causing infinite looping
1279        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1280        with the subject "ab", where knowledge that the repeated group can match
1281        nothing is needed in order to break the loop.
1283    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1284        exec(), but without supplying a callout function, matching went wrong.
1286    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1287        leak if the size of the offset vector was greater than 30. When the vector
1288        is smaller, the saved offsets during recursion go onto a local stack
1289        vector, but for larger vectors malloc() is used. It was failing to free
1290        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1291        error, in fact).
1293    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1294        heapframe that is used only when UTF-8 support is enabled. This caused no
1295        problem, but was untidy.
1297    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1298        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1299        included within another project.
1301    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1302        slightly modified by me:
1304          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1305              not building pcregrep.
1307          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1308              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1310    25. Forward references, both numeric and by name, in patterns that made use of
1311        duplicate group numbers, could behave incorrectly or give incorrect errors,
1312        because when scanning forward to find the reference group, PCRE was not
1313        taking into account the duplicate group numbers. A pattern such as
1314        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1316    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1317        the feature of a custom pointer more persuasive (as requested by a user).
1319    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1320        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1321        pre-defined.
1323    28. Added support for (*UTF8) at the start of a pattern.
1325    29. Arrange for flags added by the "release type" setting in CMake to be shown
1326        in the configuration summary.
1329    Version 7.8 05-Sep-08
1330    ---------------------
1332    1.  Replaced UCP searching code with optimized version as implemented for Ad
1333        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1334        stage table and inline lookup instead of a function, giving speed ups of 2
1335        to 5 times on some simple patterns that I tested. Permission was given to
1336        distribute the MultiStage2.py script that generates the tables (it's not in
1337        the tarball, but is in the Subversion repository).
1339    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1340        scripts.
1342    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1343        a group with a zero qualifier. The result of the study could be incorrect,
1344        or the function might crash, depending on the pattern.
1346    4.  Caseless matching was not working for non-ASCII characters in back
1347        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1348        It now works when Unicode Property Support is available.
1350    5.  In pcretest, an escape such as \x{de} in the data was always generating
1351        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1352        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1353        truncation.
1355    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1357    7.  Added two (int) casts to pcregrep when printing the difference of two
1358        pointers, in case they are 64-bit values.
1360    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1361        test 2 if it fails.
1363    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1364        and a #define of that name to empty if it is not externally set. This is to
1365        allow users of MSVC to set it if necessary.
1367    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1368        the convenience functions in the pcre_get.c source file.
1370    11. An option change at the start of a pattern that had top-level alternatives
1371        could cause overwriting and/or a crash. This command provoked a crash in
1372        some environments:
1374          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1376        This potential security problem was recorded as CVE-2008-2371.
1378    12. For a pattern where the match had to start at the beginning or immediately
1379        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1380        pcre_dfa_exec() could read past the end of the passed subject if there was
1381        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1382        pcretest so that it places the subject at the end of its malloc-ed buffer.
1384    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1385        exec() might read past the end of the data buffer in UTF-8 mode.
1387    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1388        the data contained the byte 0x85 as part of a UTF-8 character within its
1389        first line. This applied both to normal and DFA matching.
1391    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1392        /^[^d]*?$/8 failed to match "abc".
1394    16. Added a missing copyright notice to pcrecpp_internal.h.
1396    17. Make it more clear in the documentation that values returned from
1397        pcre_exec() in ovector are byte offsets, not character counts.
1399    18. Tidied a few places to stop certain compilers from issuing warnings.
1401    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1402        supplied by Stefan Weber. I made a further small update for 7.8 because
1403        there is a change of source arrangements: the pcre_searchfuncs.c module is
1404        replaced by pcre_ucd.c.
1407    Version 7.7 07-May-08
1408    ---------------------
1410    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1411        a string to a long long, pretend we don't even have a long long." This is
1412        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1414    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1415        pre-7.6 versions, which defined a global no_arg variable instead of putting
1416        it in the RE class. (See also #8 below.)
1418    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1419        Lopes.
1421    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1423        (1) The include/exclude patterns were being applied to the whole pathnames
1424            of files, instead of just to the final components.
1426        (2) If there was more than one level of directory, the subdirectories were
1427            skipped unless they satisfied the include/exclude conditions. This is
1428            inconsistent with GNU grep (and could even be seen as contrary to the
1429            pcregrep specification - which I improved to make it absolutely clear).
1430            The action now is always to scan all levels of directory, and just
1431            apply the include/exclude patterns to regular files.
1433    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1434        --exclude_dir in the tests to avoid scanning .svn directories.
1436    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1437        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1438        doesn't support NULs in patterns.
1440    7.  Added some missing "const"s to declarations of static tables in
1441        pcre_compile.c and pcre_dfa_exec.c.
1443    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1444        caused by fix #2  above. (Subsequently also a second patch to fix the
1445        first patch. And a third patch - this was a messy problem.)
1447    9.  Applied Craig's patch to remove the use of push_back().
1449    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1450        matching function regexec().
1452    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1453        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1454        references. PCRE supports relative numbers with this syntax (I don't think
1455        Oniguruma does).
1457    12. Previously, a group with a zero repeat such as (...){0} was completely
1458        omitted from the compiled regex. However, this means that if the group
1459        was called as a subroutine from elsewhere in the pattern, things went wrong
1460        (an internal error was given). Such groups are now left in the compiled
1461        pattern, with a new opcode that causes them to be skipped at execution
1462        time.
1464    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1465        to the way PCRE behaves:
1467        (a) A lone ] character is dis-allowed (Perl treats it as data).
1469        (b) A back reference to an unmatched subpattern matches an empty string
1470            (Perl fails the current match path).
1472        (c) A data ] in a character class must be notated as \] because if the
1473            first data character in a class is ], it defines an empty class. (In
1474            Perl it is not possible to have an empty class.) The empty class []
1475            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1476            The negative empty class [^] matches any one character, independently
1477            of the DOTALL setting.
1479    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1480        non-existent subpattern following a character class starting with ']' and
1481        containing () gave an internal compiling error instead of "reference to
1482        non-existent subpattern". Fortunately, when the pattern did exist, the
1483        compiled code was correct. (When scanning forwards to check for the
1484        existencd of the subpattern, it was treating the data ']' as terminating
1485        the class, so got the count wrong. When actually compiling, the reference
1486        was subsequently set up correctly.)
1488    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1489        it was being rejected as not supported by pcre_dfa_exec(), even though
1490        other assertions are supported. I have made pcre_dfa_exec() support
1491        (*FAIL).
1493    16. The implementation of 13c above involved the invention of a new opcode,
1494        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1495        cannot be changed at match time, I realized I could make a small
1496        improvement to matching performance by compiling OP_ALLANY instead of
1497        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1498        on the OP_ANY path.
1500    17. Compiling pcretest on Windows with readline support failed without the
1501        following two fixes: (1) Make the unistd.h include conditional on
1502        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1504    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1505        ncurses library to be included for pcretest when ReadLine support is
1506        requested, but also to allow for it to be overridden. This patch came from
1507        Daniel Bergström.
1509    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1510        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1511        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1512        spotting this.
1515    Version 7.6 28-Jan-08
1516    ---------------------
1518    1.  A character class containing a very large number of characters with
1519        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1520        overflow.
1522    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1523        HAVE_LONG_LONG is not defined.
1525    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1526        bring them up to date and include new features. This patch includes:
1528        - Fixed PH's badly added libz and libbz2 support.
1529        - Fixed a problem with static linking.
1530        - Added pcredemo. [But later removed - see 7 below.]
1531        - Fixed dftables problem and added an option.
1532        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1533            HAVE_LONG_LONG.
1534        - Added readline support for pcretest.
1535        - Added an listing of the option settings after cmake has run.
1537    4.  A user submitted a patch to Makefile that makes it easy to create
1538        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1539        Makefile.am that cause it to include this special target, without
1540        affecting anything else. Note that the same mingw target plus all
1541        the other distribution libraries and programs are now supported
1542        when configuring with CMake (see 6 below) instead of with
1543        Configure/Make.
1545    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1546        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1547        exported in the Windows port". It has not yet been confirmed that the patch
1548        solves the problem, but it does no harm.
1550    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1551        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1552        with CMake, and also correct the comment about stack recursion.
1554    7.  Remove the automatic building of pcredemo from the ./configure system and
1555        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1556        of a program that users should build themselves after PCRE is installed, so
1557        building it automatically is not really right. What is more, it gave
1558        trouble in some build environments.
1560    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1563    Version 7.5 10-Jan-08
1564    ---------------------
1566    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1567        values in parens when parsing an RE using the C++ wrapper."
1569    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1570        Characters greater than 255 were excluded from the class instead of being
1571        included.
1573    3.  The same bug as (2) above applied to negated POSIX classes such as
1574        [:^space:].
1576    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1577        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1578        I have changed it.
1580    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1581        first named subpattern) and a construct such as (?&a) would reference the
1582        first named subpattern whose name started with "a" (in other words, the
1583        length check was missing). Both these problems are fixed. "Subpattern name
1584        expected" is now given for (?&) (a zero-length name), and this patch also
1585        makes it give the same error for \k'' (previously it complained that that
1586        was a reference to a non-existent subpattern).
1588    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1589        this is right because (?- can be followed by option settings as well as by
1590        digits. I have, however, made the messages clearer.
1592    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1593        than the number used in the conditional) now cause a compile-time error.
1594        This is actually not compatible with Perl, which accepts such patterns, but
1595        treats the conditional as always being FALSE (as PCRE used to), but it
1596        seems to me that giving a diagnostic is better.
1598    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1599        and messages.
1601    9.  Fix two occurrences of "backslash" in comments that should have been
1602        "backspace".
1604    10. Remove two redundant lines of code that can never be obeyed (their function
1605        was moved elsewhere).
1607    11. The program that makes PCRE's Unicode character property table had a bug
1608        which caused it to generate incorrect table entries for sequences of
1609        characters that have the same character type, but are in different scripts.
1610        It amalgamated them into a single range, with the script of the first of
1611        them. In other words, some characters were in the wrong script. There were
1612        thirteen such cases, affecting characters in the following ranges:
1614          U+002b0 - U+002c1
1615          U+0060c - U+0060d
1616          U+0061e - U+00612
1617          U+0064b - U+0065e
1618          U+0074d - U+0076d
1619          U+01800 - U+01805
1620          U+01d00 - U+01d77
1621          U+01d9b - U+01dbf
1622          U+0200b - U+0200f
1623          U+030fc - U+030fe
1624          U+03260 - U+0327f
1625          U+0fb46 - U+0fbb1
1626          U+10450 - U+1049d
1628    12. The -o option (show only the matching part of a line) for pcregrep was not
1629        compatible with GNU grep in that, if there was more than one match in a
1630        line, it showed only the first of them. It now behaves in the same way as
1631        GNU grep.
1633    13. If the -o and -v options were combined for pcregrep, it printed a blank
1634        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1635        does the same. The return code can be used to tell if there were any
1636        non-matching lines.
1638    14. Added --file-offsets and --line-offsets to pcregrep.
1640    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1641        infinitely looping recursion. The bug was that positive lookaheads were not
1642        being skipped when checking for a possible empty match (negative lookaheads
1643        and both kinds of lookbehind were skipped).
1645    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1646        inclusion of <windows.h> to before rather than after the definition of
1647        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1649    17. Specifying a possessive quantifier with a specific limit for a Unicode
1650        character property caused pcre_compile() to compile bad code, which led at
1651        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1652        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1653        caused the error; without that there was no problem.
1655    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1657    19. Added --enable-pcretest-libreadline.
1659    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1660        RE::GlobalReplace(). As a result, the number of replacements returned was
1661        double what it should be. I removed one of the increments, but Craig sent a
1662        later patch that removed the other one (the right fix) and added unit tests
1663        that check the return values (which was not done before).
1665    21. Several CMake things:
1667        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1668            the names libpcre and libpcreposix, not just pcre and pcreposix.
1670        (2) The above change means that pcretest and pcregrep are now correctly
1671            linked with the newly-built libraries, not previously installed ones.
1675    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1676        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1677        UTF-8 newline character). The key issue is that the pattern starts .*;
1678        this means that the match must be either at the beginning, or after a
1679        newline. The bug was in the code for advancing after a failed match and
1680        checking that the new position followed a newline. It was not taking
1681        account of UTF-8 characters correctly.
1683    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1684        character classes. PCRE was not treating the sequence [:...:] as a
1685        character class unless the ... were all letters. Perl, however, seems to
1686        allow any characters between [: and :], though of course it rejects as
1687        unknown any "names" that contain non-letters, because all the known class
1688        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1689        for example, whereas PCRE did not - it did not recognize a POSIX character
1690        class. This seemed a bit dangerous, so the code has been changed to be
1691        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1692        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1693        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1694        Perl does, and where it didn't before.
1696    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1697        Windows environments %n is disabled by default.
1700    Version 7.4 21-Sep-07
1701    ---------------------
1703    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1704        means that a class such as [\s] counted as "explicit reference to CR or
1705        LF". That isn't really right - the whole point of the change was to try to
1706        help when there was an actual mention of one of the two characters. So now
1707        the change happens only if \r or \n (or a literal CR or LF) character is
1708        encountered.
1710    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1711        of both had grown to the point where there were only 3 bits left.
1712        Fortunately, there was spare space in the data structure, and so I have
1713        moved the internal flags into a new 16-bit field to free up more option
1714        bits.
1716    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1717        but did not set the internal JCHANGED flag - either of these is enough to
1718        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1719        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1720        start sets both bits.
1722    4.  Added options (at build time, compile time, exec time) to change \R from
1723        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1725    5.  doc/pcresyntax.html was missing from the distribution.
1727    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1728        compatibility, even though it is no longer used.
1730    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1731        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1732        windows.h file is present (where different names are used). [This was
1733        reversed later after testing - see 16 below.]
1735    8.  Changed all #include <config.h> to #include "config.h". There were also
1736        some further <pcre.h> cases that I changed to "pcre.h".
1738    9.  When pcregrep was used with the --colour option, it missed the line ending
1739        sequence off the lines that it output.
1741    10. It was pointed out to me that arrays of string pointers cause lots of
1742        relocations when a shared library is dynamically loaded. A technique of
1743        using a single long string with a table of offsets can drastically reduce
1744        these. I have refactored PCRE in four places to do this. The result is
1745        dramatic:
1747          Originally:                          290
1748          After changing UCP table:            187
1749          After changing error message table:   43
1750          After changing table of "verbs"       36
1751          After changing table of Posix names   22
1753        Thanks to the folks working on Gregex for glib for this insight.
1755    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1756        unicode-properties was also set.
1758    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1760    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1761        checked only for CRLF.
1763    14. Added casts to pcretest.c to avoid compiler warnings.
1765    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1767    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1768        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1769        entirely. This removes changes made in 7 above.
1771    17. The CMake files have been updated, and there is now more information about
1772        building with CMake in the NON-UNIX-USE document.
1775    Version 7.3 28-Aug-07
1776    ---------------------
1778     1. In the rejigging of the build system that eventually resulted in 7.1, the
1779        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1780        brackets there is not right, since it causes compilers to look for an
1781        installed pcre.h, not the version that is in the source that is being
1782        compiled (which of course may be different). I have changed it back to:
1784          #include "pcre.h"
1786        I have a vague recollection that the change was concerned with compiling in
1787        different directories, but in the new build system, that is taken care of
1788        by the VPATH setting the Makefile.
1790     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1791        when the subject happened to end in the byte 0x85 (e.g. if the last
1792        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1793        characters but of course it shouldn't be taken as a newline when it is part
1794        of another character. The bug was that, for an unlimited repeat of . in
1795        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1796        characters when looking for a newline.
1798     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1800     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1801        in debug output.
1803     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1804        long printing in the pcrecpp unittest when running under MinGW.
1806     6. ESC_K was left out of the EBCDIC table.
1808     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1809        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1810        limit also applies to "virtual nesting" when a pattern is recursive, and in
1811        this case 1000 isn't so big. I have been able to remove this limit at the
1812        expense of backing off one optimization in certain circumstances. Normally,
1813        when pcre_exec() would call its internal match() function recursively and
1814        immediately return the result unconditionally, it uses a "tail recursion"
1815        feature to save stack. However, when a subpattern that can match an empty
1816        string has an unlimited repetition quantifier, it no longer makes this
1817        optimization. That gives it a stack frame in which to save the data for
1818        checking that an empty string has been matched. Previously this was taken
1819        from the 1000-entry workspace that had been reserved. So now there is no
1820        explicit limit, but more stack is used.
1822     8. Applied Daniel's patches to solve problems with the import/export magic
1823        syntax that is required for Windows, and which was going wrong for the
1824        pcreposix and pcrecpp parts of the library. These were overlooked when this
1825        problem was solved for the main library.
1827     9. There were some crude static tests to avoid integer overflow when computing
1828        the size of patterns that contain repeated groups with explicit upper
1829        limits. As the maximum quantifier is 65535, the maximum group length was
1830        set at 30,000 so that the product of these two numbers did not overflow a
1831        32-bit integer. However, it turns out that people want to use groups that
1832        are longer than 30,000 bytes (though not repeat them that many times).
1833        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1834        made it possible to implement the integer overflow checks in a much more
1835        dynamic way, which I have now done. The artificial limitation on group
1836        length has been removed - we now have only the limit on the total length of
1837        the compiled pattern, which depends on the LINK_SIZE setting.
1839    10. Fixed a bug in the documentation for get/copy named substring when
1840        duplicate names are permitted. If none of the named substrings are set, the
1841        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1842        empty string.
1844    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1845        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1846        because the ] is interpreted as the first data character and the
1847        terminating ] is not found. PCRE has been made compatible with Perl in this
1848        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1849        cause memory overwriting.
1851    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1852        string has been matched (to stop an infinite loop). It was not recognizing
1853        a conditional subpattern that could match an empty string if that
1854        subpattern was within another subpattern. For example, it looped when
1855        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1856        condition was not nested. This bug has been fixed.
1858    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1859        past the start of the subject in the presence of bytes with the top bit
1860        set, for example "\x8aBCD".
1862    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1863        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1865    14. Optimized (?!) to (*FAIL).
1867    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1868        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1869        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1870        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1871        does: it's just the validity check that is more restrictive.
1873    16. Inserted checks for integer overflows during escape sequence (backslash)
1874        processing, and also fixed erroneous offset values for syntax errors during
1875        backslash processing.
1877    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1878        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1880    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1881        caused an overrun.
1883    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1884        something other than just ASCII characters) inside a group that had an
1885        unlimited repeat caused a loop at compile time (while checking to see
1886        whether the group could match an empty string).
1888    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1889        [\P{Any}] did so. (Error in the code for printing property names.)
1891    21. An orphan \E inside a character class could cause a crash.
1893    22. A repeated capturing bracket such as (A)? could cause a wild memory
1894        reference during compilation.
1896    23. There are several functions in pcre_compile() that scan along a compiled
1897        expression for various reasons (e.g. to see if it's fixed length for look
1898        behind). There were bugs in these functions when a repeated \p or \P was
1899        present in the pattern. These operators have additional parameters compared
1900        with \d, etc, and these were not being taken into account when moving along
1901        the compiled data. Specifically:
1903        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1904            length.
1906        (b) An item such as \pL+ within a repeated group could cause crashes or
1907            loops.
1909        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1910            "reference to non-existent subpattern" error.
1912        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1914    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1915        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1917    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1919    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1920        character were causing crashes (broken optimization).
1922    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1923        \p or \P) caused a compile-time loop.
1925    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1926        break. For example, the unstudied pattern [\r\n]A does not match the string
1927        "\r\nA" because change 7.0/46 below moves the current point on by two
1928        characters after failing to match at the start. However, the pattern \nA
1929        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1930        the same is true. There doesn't seem any very clean way out of this, but
1931        what I have chosen to do makes the common cases work: PCRE now takes note
1932        of whether there can be an explicit match for \r or \n anywhere in the
1933        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1934        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1935        pattern has explicit CR or LF references.
1937    29. Added (*CR) etc for changing newline setting at start of pattern.
1940    Version 7.2 19-Jun-07
1941    ---------------------
1943     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1944        which is apparently normally available under Windows.
1946     2. Re-jig the pcregrep tests with different newline settings in an attempt
1947        to make them independent of the local environment's newline setting.
1949     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1951     4. Some of the "internals" tests were previously cut out when the link size
1952        was not 2, because the output contained actual offsets. The recent new
1953        "Z" feature of pcretest means that these can be cut out, making the tests
1954        usable with all link sizes.
1956     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1957        stack recursion. This gives a massive performance boost under BSD, but just
1958        a small improvement under Linux. However, it saves one field in the frame
1959        in all cases.
1961     6. Added more features from the forthcoming Perl 5.10:
1963        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1964            recursion call. It refers to the nth most recently opened parentheses.
1966        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1967            to be opened parentheses.
1969        (c) Conditions that refer to capturing parentheses can be specified
1970            relatively, for example, (?(-2)... or (?(+3)...
1972        (d) \K resets the start of the current match so that everything before
1973            is not part of it.
1975        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1977        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1978            reference syntax.
1980        (g) (?| introduces a group in which the numbering of parentheses in each
1981            alternative starts with the same number.
1983        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1985     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1988     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1989        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1990        for detecting groups that can match an empty string.
1992     9. A pattern with a very large number of alternatives (more than several
1993        hundred) was running out of internal workspace during the pre-compile
1994        phase, where pcre_compile() figures out how much memory will be needed. A
1995        bit of new cunning has reduced the workspace needed for groups with
1996        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1997        workspace instead of running out of the 4096 that are available.
1999    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
2001    11. Applied patch from Google to remove an optimization that didn't quite work.
2002        The report of the bug said:
2004          pcrecpp::RE("a*").FullMatch("aaa") matches, while
2005          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
2006          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
2008    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
2009        it matched the wrong number of bytes.
2012    Version 7.1 24-Apr-07
2013    ---------------------
2015     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
2016        that is more "standard", making use of automake and other Autotools. There
2017        is some re-arrangement of the files and adjustment of comments consequent
2018        on this.
2020     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
2021        for recursive directory scanning broke on some systems because the files
2022        are not scanned in any specific order and on different systems the order
2023        was different. A call to "sort" has been inserted into RunGrepTest for the
2024        approprate test as a short-term fix. In the longer term there may be an
2025        alternative.
2027     3. I had an email from Eric Raymond about problems translating some of PCRE's
2028        man pages to HTML (despite the fact that I distribute HTML pages, some
2029        people do their own conversions for various reasons). The problems
2030        concerned the use of low-level troff macros .br and .in. I have therefore
2031        removed all such uses from the man pages (some were redundant, some could
2032        be replaced by .nf/.fi pairs). The 132html script that I use to generate
2033        HTML has been updated to handle .nf/.fi and to complain if it encounters
2034        .br or .in.
2036     4. Updated comments in configure.ac that get placed in config.h.in and also
2037        arranged for config.h to be included in the distribution, with the name
2038        config.h.generic, for the benefit of those who have to compile without
2039        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
2041     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
2042        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
2043        makevp.bat for the current PCRE, using the additional files
2044        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
2046     6. A Windows user reported a minor discrepancy with test 2, which turned out
2047        to be caused by a trailing space on an input line that had got lost in his
2048        copy. The trailing space was an accident, so I've just removed it.
2050     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
2051        that is needed.
2053     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
2054        as "const" (a) because they are and (b) because it helps the PHP
2055        maintainers who have recently made a script to detect big data structures
2056        in the php code that should be moved to the .rodata section. I remembered
2057        to update Builducptable as well, so it won't revert if ucptable.h is ever
2058        re-created.
2060     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
2061        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
2062        order to be able to cut out the UTF-8 tables in the latter when UTF-8
2063        support is not required. This saves 1.5-2K of code, which is important in
2064        some applications.
2066        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
2067        so as not to refer to the tables, even though these functions will never be
2068        called when UTF-8 support is disabled. Otherwise there are problems with a
2069        shared library.
2071    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
2073        (a) It was defining its arguments as char * instead of void *.
2075        (b) It was assuming that all moves were upwards in memory; this was true
2076            a long time ago when I wrote it, but is no longer the case.
2078        The emulated memove() is provided for those environments that have neither
2079        memmove() nor bcopy(). I didn't think anyone used it these days, but that
2080        is clearly not the case, as these two bugs were recently reported.
2082    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
2083        and Detrail to create the HTML documentation, the .txt form of the man
2084        pages, and it removes trailing spaces from listed files. It also creates
2085        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
2086        case, it wraps all the #defines with #ifndefs. This script should be run
2087        before "make dist".
2089    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
2090        with Unicode property support.
2092        (a) For a maximizing quantifier, if the two different cases of the
2093            character were of different lengths in their UTF-8 codings (there are
2094            some cases like this - I found 11), and the matching function had to
2095            back up over a mixture of the two cases, it incorrectly assumed they
2096            were both the same length.
2098        (b) When PCRE was configured to use the heap rather than the stack for
2099            recursion during matching, it was not correctly preserving the data for
2100            the other case of a UTF-8 character when checking ahead for a match
2101            while processing a minimizing repeat. If the check also involved
2102            matching a wide character, but failed, corruption could cause an
2103            erroneous result when trying to check for a repeat of the original
2104            character.
2106    13. Some tidying changes to the testing mechanism:
2108        (a) The RunTest script now detects the internal link size and whether there
2109            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
2110            values substituted by "configure". (The RunGrepTest script already did
2111            this for UTF-8.) The configure.ac script no longer substitutes the
2112            relevant variables.
2114        (b) The debugging options /B and /D in pcretest show the compiled bytecode
2115            with length and offset values. This means that the output is different
2116            for different internal link sizes. Test 2 is skipped for link sizes
2117            other than 2 because of this, bypassing the problem. Unfortunately,
2118            there was also a test in test 3 (the locale tests) that used /B and
2119            failed for link sizes other than 2. Rather than cut the whole test out,
2120            I have added a new /Z option to pcretest that replaces the length and
2121            offset values with spaces. This is now used to make test 3 independent
2122            of link size. (Test 2 will be tidied up later.)
2124    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
2125        segmentation fault instead of returning the appropriate error message.
2127    15. In multiline mode when the newline sequence was set to "any", the pattern
2128        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
2129        This doesn't seem right; it now treats the CRLF combination as the line
2130        ending, and so does not match in that case. It's only a pattern such as ^$
2131        that would hit this one: something like ^ABC$ would have failed after \r
2132        and then tried again after \r\n.
2134    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
2135        in an attempt to make files that differ only in their line terminators
2136        compare equal. This works on Linux.
2138    17. Under certain error circumstances pcregrep might try to free random memory
2139        as it exited. This is now fixed, thanks to valgrind.
2141    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
2142        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
2143        was because its rules for how to advance for /g after matching an empty
2144        string at the end of a line did not allow for this case. They now check for
2145        it specially.
2147    20. pcretest is supposed to handle patterns and data of any length, by
2148        extending its buffers when necessary. It was getting this wrong when the
2149        buffer for a data line had to be extended.
2151    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
2152        CRLF as a newline sequence.
2154    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
2155        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
2156        I have nevertheless tidied it up.
2158    23. Added some casts to kill warnings from HP-UX ia64 compiler.
2160    24. Added a man page for pcre-config.
2163    Version 7.0 19-Dec-06
2164    ---------------------
2166     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2167        moving to gcc 4.1.1.
2169     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2170        sys/time.h, which is documented as needed for this function. It doesn't
2171        seem to matter on Linux, but it showed up on some releases of OS X.
2173     3. It seems that there are systems where bytes whose values are greater than
2174        127 match isprint() in the "C" locale. The "C" locale should be the
2175        default when a C program starts up. In most systems, only ASCII printing
2176        characters match isprint(). This difference caused the output from pcretest
2177        to vary, making some of the tests fail. I have changed pcretest so that:
2179        (a) When it is outputting text in the compiled version of a pattern, bytes
2180            other than 32-126 are always shown as hex escapes.
2182        (b) When it is outputting text that is a matched part of a subject string,
2183            it does the same, unless a different locale has been set for the match
2184            (using the /L modifier). In this case, it uses isprint() to decide.
2186     4. Fixed a major bug that caused incorrect computation of the amount of memory
2187        required for a compiled pattern when options that changed within the
2188        pattern affected the logic of the preliminary scan that determines the
2189        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2190        that the computed length was too small. The symptoms of this bug were
2191        either the PCRE error "internal error: code overflow" from pcre_compile(),
2192        or a glibc crash with a message such as "pcretest: free(): invalid next
2193        size (fast)". Examples of patterns that provoked this bug (shown in
2194        pcretest format) are:
2196          /(?-x: )/x
2197          /(?x)(?-x: \s*#\s*)/
2198          /((?i)[\x{c0}])/8
2199          /(?i:[\x{c0}])/8
2201        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2202        is now done differently.
2204     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2205        wrapper classes; (b) implement a new function in the C++ scanner that is
2206        more efficient than the old way of doing things because it avoids levels of
2207        recursion in the regex matching; (c) add a paragraph to the documentation
2208        for the FullMatch() function.
2210     6. The escape sequence \n was being treated as whatever was defined as
2211        "newline". Not only was this contrary to the documentation, which states
2212        that \n is character 10 (hex 0A), but it also went horribly wrong when
2213        "newline" was defined as CRLF. This has been fixed.
2215     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2216        was being set to -1 for the "end of line" case (supposedly a value that no
2217        character can have). Though this value is never used (the check for end of
2218        line is "zero bytes in current character"), it caused compiler complaints.
2219        I've changed it to 0xffffffff.
2221     8. In pcre_version.c, the version string was being built by a sequence of
2222        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2223        string (as it is for production releases) called a macro with an empty
2224        argument. The C standard says the result of this is undefined. The gcc
2225        compiler treats it as an empty string (which was what was wanted) but it is
2226        reported that Visual C gives an error. The source has been hacked around to
2227        avoid this problem.
2229     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2230        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2231        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2232        of them did).
2234    10. Originally, pcretest opened its input and output without "b"; then I was
2235        told that "b" was needed in some environments, so it was added for release
2236        5.0 to both the input and output. (It makes no difference on Unix-like
2237        systems.) Later I was told that it is wrong for the input on Windows. I've
2238        now abstracted the modes into two macros, to make it easier to fiddle with
2239        them, and removed "b" from the input mode under Windows.
2241    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2243    12. Added -help and --help to pcretest as an official way of being reminded
2244        of the options.
2246    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2247        and pcrecpp.cc because they annoy compilers at high warning levels.
2249    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2251    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2252        scripts are not C programs :-) and which was not noticed because it works
2253        on Linux.
2255    16. pcretest is supposed to handle any length of pattern and data line (as one
2256        line or as a continued sequence of lines) by extending its input buffer if
2257        necessary. This feature was broken for very long pattern lines, leading to
2258        a string of junk being passed to pcre_compile() if the pattern was longer
2259        than about 50K.
2261    17. I have done a major re-factoring of the way pcre_compile() computes the
2262        amount of memory needed for a compiled pattern. Previously, there was code
2263        that made a preliminary scan of the pattern in order to do this. That was
2264        OK when PCRE was new, but as the facilities have expanded, it has become
2265        harder and harder to keep it in step with the real compile phase, and there
2266        have been a number of bugs (see for example, 4 above). I have now found a
2267        cunning way of running the real compile function in a "fake" mode that
2268        enables it to compute how much memory it would need, while actually only
2269        ever using a few hundred bytes of working memory and without too many
2270        tests of the mode. This should make future maintenance and development
2271        easier. A side effect of this work is that the limit of 200 on the nesting
2272        depth of parentheses has been removed (though this was never a serious
2273        limitation, I suspect). However, there is a downside: pcre_compile() now
2274        runs more slowly than before (30% or more, depending on the pattern). I
2275        hope this isn't a big issue. There is no effect on runtime performance.
2277    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2278        newline (only possible for the last line of a file) and it was a
2279        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2281    19. Added additional timing features to pcretest. (1) The -tm option now times
2282        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2283        separate command line item, by a number that specifies the number of
2284        repeats to use when timing. The default is 50000; this gives better
2285        precision, but takes uncomfortably long for very large patterns.
2287    20. Extended pcre_study() to be more clever in cases where a branch of a
2288        subpattern has no definite first character. For example, (a*|b*)[cd] would
2289        previously give no result from pcre_study(). Now it recognizes that the
2290        first character must be a, b, c, or d.
2292    21. There was an incorrect error "recursive call could loop indefinitely" if
2293        a subpattern (or the entire pattern) that was being tested for matching an
2294        empty string contained only one non-empty item after a nested subpattern.
2295        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2296        incorrectly, because the \d was being skipped in the check.
2298    22. The pcretest program now has a new pattern option /B and a command line
2299        option -b, which is equivalent to adding /B to every pattern. This causes
2300        it to show the compiled bytecode, without the additional information that
2301        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2302        is the same as /B/I).
2304    23. A new optimization is now able automatically to treat some sequences such
2305        as a*b as a*+b. More specifically, if something simple (such as a character
2306        or a simple class like \d) has an unlimited quantifier, and is followed by
2307        something that cannot possibly match the quantified thing, the quantifier
2308        is automatically "possessified".
2310    24. A recursive reference to a subpattern whose number was greater than 39
2311        went wrong under certain circumstances in UTF-8 mode. This bug could also
2312        have affected the operation of pcre_study().
2314    25. Realized that a little bit of performance could be had by replacing
2315        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2317    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2319    27. Possessive quantifiers such as a++ were previously implemented by turning
2320        them into atomic groups such as ($>a+). Now they have their own opcodes,
2321        which improves performance. This includes the automatically created ones
2322        from 23 above.
2324    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2325        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2326        the first matched character to be a colon. This applied both to named and
2327        numbered groups.
2329    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2331    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2332        building PCRE on Windows easier, so I have included it in the distribution.
2334    31. There is now a check in pcretest against a ridiculously large number being
2335        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2336        loop, the loop is abandoned.
2338    32. Forward references to subpatterns in conditions such as (?(2)...) where
2339        subpattern 2 is defined later cause pcre_compile() to search forwards in
2340        the pattern for the relevant set of parentheses. This search went wrong
2341        when there were unescaped parentheses in a character class, parentheses
2342        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2344    33. "Subroutine" calls and backreferences were previously restricted to
2345        referencing subpatterns earlier in the regex. This restriction has now
2346        been removed.
2348    34. Added a number of extra features that are going to be in Perl 5.10. On the
2349        whole, these are just syntactic alternatives for features that PCRE had
2350        previously implemented using the Python syntax or my own invention. The
2351        other formats are all retained for compatibility.
2353        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2354            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2355            also .NET compatible.
2357        (b) A recursion or subroutine call to a named group can now be defined as
2358            (?&name) as well as (?P>name).
2360        (c) A backreference to a named group can now be defined as \k<name> or
2361            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2362            5.10, are also .NET compatible.
2364        (d) A conditional reference to a named group can now use the syntax
2365            (?(<name>) or (?('name') as well as (?(name).
2367        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2368            groups (named and numbered) that are never evaluated inline, but can be
2369            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2370            is always false. There may be only one alternative in such a group.
2372        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2373            as the simple (?(R). The condition is true only if the most recent
2374            recursion is that of the given number or name. It does not search out
2375            through the entire recursion stack.
2377        (g) The escape \gN or \g{N} has been added, where N is a positive or
2378            negative number, specifying an absolute or relative reference.
2380    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2381        some "unreachable code" warnings.
2383    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2384        things, this adds five new scripts.
2386    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2387        There were also incompatibilities regarding the handling of \Q..\E inside
2388        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2389        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2391    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2392        matches an empty string, and forcibly breaks the loop. There were bugs in
2393        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2394        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2395        separate and independent bugs (that affected different cases) have been
2396        fixed.
2398    39. Refactored the code to abolish the use of different opcodes for small
2399        capturing bracket numbers. This is a tidy that I avoided doing when I
2400        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2401        The new approach is not only tidier, it makes it possible to reduce the
2402        memory needed to fix the previous bug (38).
2404    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2405        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2406        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2407        mode.
2409    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2410        report.
2412    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2413        copy construction and assignment in the C++ wrapper.
2415    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2416        couple of bugs that could have given wrong results in the "--newline=crlf"
2417        case.
2419    44. Added a number of casts and did some reorganization of signed/unsigned int
2420        variables following suggestions from Dair Grant. Also renamed the variable
2421        "this" as "item" because it is a C++ keyword.
2423    45. Arranged for dftables to add
2425          #include "pcre_internal.h"
2427        to pcre_chartables.c because without it, gcc 4.x may remove the array
2428        definition from the final binary if PCRE is built into a static library and
2429        dead code stripping is activated.
2431    46. For an unanchored pattern, if a match attempt fails at the start of a
2432        newline sequence, and the newline setting is CRLF or ANY, and the next two
2433        characters are CRLF, advance by two characters instead of one.
2436    Version 6.7 04-Jul-06
2437    ---------------------
2439     1. In order to handle tests when input lines are enormously long, pcretest has
2440        been re-factored so that it automatically extends its buffers when
2441        necessary. The code is crude, but this _is_ just a test program. The
2442        default size has been increased from 32K to 50K.
2444     2. The code in pcre_study() was using the value of the re argument before
2445        testing it for NULL. (Of course, in any sensible call of the function, it
2446        won't be NULL.)
2448     3. The memmove() emulation function in pcre_internal.h, which is used on
2449        systems that lack both memmove() and bcopy() - that is, hardly ever -
2450        was missing a "static" storage class specifier.
2452     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2453        containing an extended class (one that cannot be represented by a bitmap
2454        because it contains high-valued characters or Unicode property items, e.g.
2455        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2456        pattern, but PCRE should not loop if you do not (it no longer does).
2457        [Detail: two cases were found: (a) a repeated subpattern containing an
2458        extended class; (b) a recursive reference to a subpattern that followed a
2459        previous extended class. It wasn't skipping over the extended class
2460        correctly when UTF-8 mode was not set.]
2462     5. A negated single-character class was not being recognized as fixed-length
2463        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2464        compile error "lookbehind assertion is not fixed length".
2466     6. The RunPerlTest auxiliary script was showing an unexpected difference
2467        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2468        write a Perl script that can interpret lines of an input file either as
2469        byte characters or as UTF-8, which is what "perltest" was being required to
2470        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2471        can't do is switch easily at run time between having the "use utf8;" pragma
2472        or not. In the end, I fudged it by using the RunPerlTest script to insert
2473        "use utf8;" explicitly for the UTF-8 tests.
2475     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2476        the end of the subject string, contrary to the documentation and to what
2477        Perl does. This was true of both matching functions. Now it matches only at
2478        the start of the subject and immediately after *internal* newlines.
2480     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2481        a pointer to an int instead of a pointer to an unsigned long int. This
2482        caused problems on 64-bit systems.
2484     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2485        instance of the 'standard' template library not being so standard".
2487    10. There was no check on the number of named subpatterns nor the maximum
2488        length of a subpattern name. The product of these values is used to compute
2489        the size of the memory block for a compiled pattern. By supplying a very
2490        long subpattern name and a large number of named subpatterns, the size
2491        computation could be caused to overflow. This is now prevented by limiting
2492        the length of names to 32 characters, and the number of named subpatterns
2493        to 10,000.
2495    11. Subpatterns that are repeated with specific counts have to be replicated in
2496        the compiled pattern. The size of memory for this was computed from the
2497        length of the subpattern and the repeat count. The latter is limited to
2498        65535, but there was no limit on the former, meaning that integer overflow
2499        could in principle occur. The compiled length of a repeated subpattern is
2500        now limited to 30,000 bytes in order to prevent this.
2502    12. Added the optional facility to have named substrings with the same name.
2504    13. Added the ability to use a named substring as a condition, using the
2505        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2506        are numbers (not recommended). Forward references are permitted.
2508    14. Added forward references in named backreferences (if you see what I mean).
2510    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2511        pattern could run off the end of the subject. For example, the pattern
2512        "(?s)(.{1,5})"8 did this with the subject "ab".
2514    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2515        PCRE_CASELESS was set when matching characters that were quantified with ?
2516        or *.
2518    17. A character class other than a single negated character that had a minimum
2519        but no maximum quantifier - for example [ab]{6,} - was not handled
2520        correctly by pce_dfa_exec(). It would match only one character.
2522    18. A valid (though odd) pattern that looked like a POSIX character
2523        class but used an invalid character after [ (for example [[,abc,]]) caused
2524        pcre_compile() to give the error "Failed: internal error: code overflow" or
2525        in some cases to crash with a glibc free() error. This could even happen if
2526        the pattern terminated after [[ but there just happened to be a sequence of
2527        letters, a binary zero, and a closing ] in the memory that followed.
2529    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2530        over the years. Originally (before any Unicode support), just the bottom 8
2531        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2532        output from "man perlunicode" includes this:
2534          The regular expression compiler produces polymorphic opcodes.  That
2535          is, the pattern adapts to the data and automatically switches to
2536          the Unicode character scheme when presented with Unicode data--or
2537          instead uses a traditional byte scheme when presented with byte
2538          data.
2540        Sadly, a wide octal escape does not cause a switch, and in a string with
2541        no other multibyte characters, these octal escapes are treated as before.
2542        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2543        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2544        Unicode string.
2546        I have not perpetrated such confusion in PCRE. Up till now, it took just
2547        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2548        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2549        translate to the appropriate multibyte character.
2551    29. Applied some refactoring to reduce the number of warnings from Microsoft
2552        and Borland compilers. This has included removing the fudge introduced
2553        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2554        a warning about an unused variable.
2556    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2557        characters since release 4.0, because Perl (from release 5.004) does not.
2558        [Or at least, is documented not to: some releases seem to be in conflict
2559        with the documentation.] However, when a pattern was studied with
2560        pcre_study() and all its branches started with \s, PCRE still included VT
2561        as a possible starting character. Of course, this did no harm; it just
2562        caused an unnecessary match attempt.
2564    22. Removed a now-redundant internal flag bit that recorded the fact that case
2565        dependency changed within the pattern. This was once needed for "required
2566        byte" processing, but is no longer used. This recovers a now-scarce options
2567        bit. Also moved the least significant internal flag bit to the most-
2568        significant bit of the word, which was not previously used (hangover from
2569        the days when it was an int rather than a uint) to free up another bit for
2570        the future.
2572    23. Added support for CRLF line endings as well as CR and LF. As well as the
2573        default being selectable at build time, it can now be changed at runtime
2574        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2575        specify that it is scanning data with non-default line endings.
2577    24. Changed the definition of CXXLINK to make it agree with the definition of
2578        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2580    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2581        recursions. This makes a big different to stack usage for some patterns.
2583    26. If a subpattern containing a named recursion or subroutine reference such
2584        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2585        the space required for the compiled pattern went wrong and gave too small a
2586        value. Depending on the environment, this could lead to "Failed: internal
2587        error: code overflow at offset 49" or "glibc detected double free or
2588        corruption" errors.
2590    27. Applied patches from Google (a) to support the new newline modes and (b) to
2591        advance over multibyte UTF-8 characters in GlobalReplace.
2593    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2594        difference for some implementation of PCRE in some Windows version.
2596    29. Added some extra testing facilities to pcretest:
2598        \q<number>   in a data line sets the "match limit" value
2599        \Q<number>   in a data line sets the "match recursion limt" value
2600        -S <number>  sets the stack size, where <number> is in megabytes
2602        The -S option isn't available for Windows.
2605    Version 6.6 06-Feb-06
2606    ---------------------
2608     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2609        in pcreposix.h. I have copied the definition from pcre.h.
2611     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2612        because pcre.h is no longer a built file.
2614     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2615        not normally included in the compiled code.
2618    Version 6.5 01-Feb-06
2619    ---------------------
2621     1. When using the partial match feature with pcre_dfa_exec(), it was not
2622        anchoring the second and subsequent partial matches at the new starting
2623        point. This could lead to incorrect results. For example, with the pattern
2624        /1234/, partially matching against "123" and then "a4" gave a match.
2626     2. Changes to pcregrep:
2628        (a) All non-match returns from pcre_exec() were being treated as failures
2629            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2630            error message is output. Some extra information is given for the
2631            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2632            probably the only errors that are likely to be caused by users (by
2633            specifying a regex that has nested indefinite repeats, for instance).
2634            If there are more than 20 of these errors, pcregrep is abandoned.
2636        (b) A binary zero was treated as data while matching, but terminated the
2637            output line if it was written out. This has been fixed: binary zeroes
2638            are now no different to any other data bytes.
2640        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2641            used to set a locale for matching. The --locale=xxxx long option has
2642            been added (no short equivalent) to specify a locale explicitly on the
2643            pcregrep command, overriding the environment variables.
2645        (d) When -B was used with -n, some line numbers in the output were one less
2646            than they should have been.
2648        (e) Added the -o (--only-matching) option.
2650        (f) If -A or -C was used with -c (count only), some lines of context were
2651            accidentally printed for the final match.
2653        (g) Added the -H (--with-filename) option.
2655        (h) The combination of options -rh failed to suppress file names for files
2656            that were found from directory arguments.
2658        (i) Added the -D (--devices) and -d (--directories) options.
2660        (j) Added the -F (--fixed-strings) option.
2662        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2664        (l) Added the --colo(u)r option.
2666        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2667            is not present by default.
2669     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2670        items such as (?R) or (?1), when the recursion could match a number of
2671        alternatives. If it matched one of the alternatives, but subsequently,
2672        outside the recursion, there was a failure, the code tried to back up into
2673        the recursion. However, because of the way PCRE is implemented, this is not
2674        possible, and the result was an incorrect result from the match.
2676        In order to prevent this happening, the specification of recursion has
2677        been changed so that all such subpatterns are automatically treated as
2678        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2680     4. I had overlooked the fact that, in some locales, there are characters for
2681        which isalpha() is true but neither isupper() nor islower() are true. In
2682        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2683        and ordfeminine) are like this. This affected the treatment of \w and \W
2684        when they appeared in character classes, but not when they appeared outside
2685        a character class. The bit map for "word" characters is now created
2686        separately from the results of isalnum() instead of just taking it from the
2687        upper, lower, and digit maps. (Plus the underscore character, of course.)
2689     5. The above bug also affected the handling of POSIX character classes such as
2690        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2691        permanent tables. Instead, the bit maps for such a class were previously
2692        created as the appropriate unions of the upper, lower, and digit bitmaps.
2693        Now they are created by subtraction from the [[:word:]] class, which has
2694        its own bitmap.
2696     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2697        It is created by subtracting the vertical space characters (\x09, \x0a,
2698        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2699        subtraction was done in the overall bitmap for a character class, meaning
2700        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2701        be recognized. This bug has been fixed.
2703     7. Patches from the folks at Google:
2705          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2706          real life, but is still worth protecting against".
2708          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2709          regular expressions".
2711          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2712          have it.
2714          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2715          "configure" and the latter not, in order to fix a problem somebody had
2716          with compiling the Arg class on HP-UX.
2718          (e) Improve the error-handling of the C++ wrapper a little bit.
2720          (f) New tests for checking recursion limiting.
2722     8. The pcre_memmove() function, which is used only if the environment does not
2723        have a standard memmove() function (and is therefore rarely compiled),
2724        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2725        returning a result (though PCRE never actually uses the result).
2727     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2728        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2729        returned instead of calling malloc() with an overflowing number that would
2730        most likely cause subsequent chaos.
2732    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2734    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2735        with this option is matched, the nmatch and pmatch options of regexec() are
2736        ignored.
2738    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2739        provided in case anyone wants to the the POSIX interface with UTF-8
2740        strings.
2742    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2743        C++ linking (needed for some HP-UX environments).
2745    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2746        (unused parameter) and in the pcre_printint() function (omitted "default"
2747        switch label when the default is to do nothing).
2749    15. Added some code to make it possible, when PCRE is compiled as a C++
2750        library, to replace subject pointers for pcre_exec() with a smart pointer
2751        class, thus making it possible to process discontinuous strings.
2753    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2754        much the same function. They were added by different people who were trying
2755        to make PCRE easy to compile on non-Unix systems. It has been suggested
2756        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2757        for compiling on Windows systems. I have therefore replaced it with
2758        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2759        defaults to "extern" for C or "extern C" for C++, which works fine on
2760        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2761        SCOPE with something explicit in config.h. In addition:
2763        (a) pcreposix.h still had just "extern" instead of either of these macros;
2764            I have replaced it with PCRE_DATA_SCOPE.
2766        (b) Functions such as _pcre_xclass(), which are internal to the library,
2767            but external in the C sense, all had PCRE_EXPORT in their definitions.
2768            This is apparently wrong for the Windows case, so I have removed it.
2769            (It makes no difference on Unix-like systems.)
2771    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2772        of recursive calls to match(). This is different to MATCH_LIMIT because
2773        that limits the total number of calls to match(), not all of which increase
2774        the depth of recursion. Limiting the recursion depth limits the amount of
2775        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2776        when PCRE is compiled, and changed at run time. A patch from Google adds
2777        this functionality to the C++ interface.
2779    18. Changes to the handling of Unicode character properties:
2781        (a) Updated the table to Unicode 4.1.0.
2783        (b) Recognize characters that are not in the table as "Cn" (undefined).
2785        (c) I revised the way the table is implemented to a much improved format
2786            which includes recognition of ranges. It now supports the ranges that
2787            are defined in UnicodeData.txt, and it also amalgamates other
2788            characters into ranges. This has reduced the number of entries in the
2789            table from around 16,000 to around 3,000, thus reducing its size
2790            considerably. I realized I did not need to use a tree structure after
2791            all - a binary chop search is just as efficient. Having reduced the
2792            number of entries, I extended their size from 6 bytes to 8 bytes to
2793            allow for more data.
2795        (d) Added support for Unicode script names via properties such as \p{Han}.
2797    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2798        matching that character.
2800    20. When matching a repeated Unicode property with a minimum greater than zero,
2801        (for example \pL{2,}), PCRE could look past the end of the subject if it
2802        reached it while seeking the minimum number of characters. This could
2803        happen only if some of the characters were more than one byte long, because
2804        there is a check for at least the minimum number of bytes.
2806    21. Refactored the implementation of \p and \P so as to be more general, to
2807        allow for more different types of property in future. This has changed the
2808        compiled form incompatibly. Anybody with saved compiled patterns that use
2809        \p or \P will have to recompile them.
2811    22. Added "Any" and "L&" to the supported property types.
2813    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2814        but give a compile time error if the value is greater than 0xff.
2816    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2817        accidentally not being installed or uninstalled.
2819    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2820        made were to insert the current release number. This seemed silly, because
2821        it made things harder for people building PCRE on systems that don't run
2822        "configure". I have turned pcre.h into a distributed file, no longer built
2823        by "configure", with the version identification directly included. There is
2824        no longer a pcre.h.in file.
2826        However, this change necessitated a change to the pcre-config script as
2827        well. It is built from pcre-config.in, and one of the substitutions was the
2828        release number. I have updated configure.ac so that ./configure now finds
2829        the release number by grepping pcre.h.
2831    26. Added the ability to run the tests under valgrind.
2834    Version 6.4 05-Sep-05
2835    ---------------------
2837     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2838        "--" to be printed when multiple files were scanned, even when none of the
2839        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2840        consider it to be a bug, and have restored the previous behaviour.
2842     2. A couple of code tidies to get rid of compiler warnings.
2844     3. The pcretest program used to cheat by referring to symbols in the library
2845        whose names begin with _pcre_. These are internal symbols that are not
2846        really supposed to be visible externally, and in some environments it is
2847        possible to suppress them. The cheating is now confined to including
2848        certain files from the library's source, which is a bit cleaner.
2850     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2851        file's purpose clearer.
2853     5. Reorganized pcre_ucp_findchar().
2856    Version 6.3 15-Aug-05
2857    ---------------------
2859     1. The file libpcre.pc.in did not have general read permission in the tarball.
2861     2. There were some problems when building without C++ support:
2863        (a) If C++ support was not built, "make install" and "make test" still
2864            tried to test it.
2866        (b) There were problems when the value of CXX was explicitly set. Some
2867            changes have been made to try to fix these, and ...
2869        (c) --disable-cpp can now be used to explicitly disable C++ support.
2871        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2872            backslash in a target when C++ was disabled. This confuses some
2873            versions of "make", apparently. Using an intermediate variable solves
2874            this. (Same for CPP_LOBJ.)
2876     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2877        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2878        necessary on certain architectures.
2880     4. Added a setting of -export-symbols-regex to the link command to remove
2881        those symbols that are exported in the C sense, but actually are local
2882        within the library, and not documented. Their names all begin with
2883        "_pcre_". This is not a perfect job, because (a) we have to except some
2884        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2885        available (and never for static libraries). I have made a note to try to
2886        find a way round (a) in the future.
2889    Version 6.2 01-Aug-05
2890    ---------------------
2892     1. There was no test for integer overflow of quantifier values. A construction
2893        such as {1111111111111111} would give undefined results. What is worse, if
2894        a minimum quantifier for a parenthesized subpattern overflowed and became
2895        negative, the calculation of the memory size went wrong. This could have
2896        led to memory overwriting.
2898     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2900     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2901        operating environments where this matters.
2903     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2904        PCRE options from within the C++ wrapper.
2906     5. Named capturing subpatterns were not being correctly counted when a pattern
2907        was compiled. This caused two problems: (a) If there were more than 100
2908        such subpatterns, the calculation of the memory needed for the whole
2909        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2910        back references of the form \12, where the number was greater than 9, were
2911        not recognized as back references, even though there were sufficient
2912        previous subpatterns.
2914     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2915        versions of gcc, e.g. 2.95.4.
2918    Version 6.1 21-Jun-05
2919    ---------------------
2921     1. There was one reference to the variable "posix" in pcretest.c that was not
2922        surrounded by "#if !defined NOPOSIX".
2924     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2925        the cross-check on the old pcre_info() function, for the benefit of the
2926        cut-down version of PCRE that is currently imported into Exim.
2928     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2929        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2930        patterns that start (?i) but I don't think that matters. The use of (?i) is
2931        just an example; this all applies to the other options as well.
2933     4. Since libtool seems to echo the compile commands it is issuing, the output
2934        from "make" can be reduced a bit by putting "@" in front of each libtool
2935        compile command.
2937     5. Patch from the folks at Google for configure.in to be a bit more thorough
2938        in checking for a suitable C++ installation before trying to compile the
2939        C++ stuff. This should fix a reported problem when a compiler was present,
2940        but no suitable headers.
2942     6. The man pages all had just "PCRE" as their title. I have changed them to
2943        be the relevant file name. I have also arranged that these names are
2944        retained in the file doc/pcre.txt, which is a concatenation in text format
2945        of all the man pages except the little individual ones for each function.
2947     7. The NON-UNIX-USE file had not been updated for the different set of source
2948        files that come with release 6. I also added a few comments about the C++
2949        wrapper.
2952    Version 6.0 07-Jun-05
2953    ---------------------
2955     1. Some minor internal re-organization to help with my DFA experiments.
2957     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2958        didn't matter for the library itself when fully configured, but did matter
2959        when compiling without UCP support, or within Exim, where the ucp files are
2960        not imported.
2962     3. Refactoring of the library code to split up the various functions into
2963        different source modules. The addition of the new DFA matching code (see
2964        below) to a single monolithic source would have made it really too
2965        unwieldy, quite apart from causing all the code to be include in a
2966        statically linked application, when only some functions are used. This is
2967        relevant even without the DFA addition now that patterns can be compiled in
2968        one application and matched in another.
2970        The downside of splitting up is that there have to be some external
2971        functions and data tables that are used internally in different modules of
2972        the library but which are not part of the API. These have all had their
2973        names changed to start with "_pcre_" so that they are unlikely to clash
2974        with other external names.
2976     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2977        a different (DFA) algorithm. Although it is slower than the original
2978        function, it does have some advantages for certain types of matching
2979        problem.
2981     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2982        including restarting after a partial match.
2984     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2985        defined when compiling for Windows was sent to me. I have put it into the
2986        code, though I have no means of testing or verifying it.
2988     7. Added the pcre_refcount() auxiliary function.
2990     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2991        match before or at the first newline in the subject string. In pcretest,
2992        the /f option on a pattern can be used to set this.
2994     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2995        would behave wrongly. This has been present in PCRE since release 4.0.
2997    10. A number of changes to the pcregrep command:
2999        (a) Refactored how -x works; insert ^(...)$ instead of setting
3000            PCRE_ANCHORED and checking the length, in preparation for adding
3001            something similar for -w.
3003        (b) Added the -w (match as a word) option.
3005        (c) Refactored the way lines are read and buffered so as to have more
3006            than one at a time available.
3008        (d) Implemented a pcregrep test script.
3010        (e) Added the -M (multiline match) option. This allows patterns to match
3011            over several lines of the subject. The buffering ensures that at least
3012            8K, or the rest of the document (whichever is the shorter) is available
3013            for matching (and similarly the previous 8K for lookbehind assertions).
3015        (f) Changed the --help output so that it now says
3017              -w, --word-regex(p)
3019            instead of two lines, one with "regex" and the other with "regexp"
3020            because that confused at least one person since the short forms are the
3021            same. (This required a bit of code, as the output is generated
3022            automatically from a table. It wasn't just a text change.)
3024        (g) -- can be used to terminate pcregrep options if the next thing isn't an
3025            option but starts with a hyphen. Could be a pattern or a path name
3026            starting with a hyphen, for instance.
3028        (h) "-" can be given as a file name to represent stdin.
3030        (i) When file names are being printed, "(standard input)" is used for
3031            the standard input, for compatibility with GNU grep. Previously
3032            "<stdin>" was used.
3034        (j) The option --label=xxx can be used to supply a name to be used for
3035            stdin when file names are being printed. There is no short form.
3037        (k) Re-factored the options decoding logic because we are going to add
3038            two more options that take data. Such options can now be given in four
3039            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
3041        (l) Added the -A, -B, and -C options for requesting that lines of context
3042            around matches be printed.
3044        (m) Added the -L option to print the names of files that do not contain
3045            any matching lines, that is, the complement of -l.
3047        (n) The return code is 2 if any file cannot be opened, but pcregrep does
3048            continue to scan other files.
3050        (o) The -s option was incorrectly implemented. For compatibility with other
3051            greps, it now suppresses the error message for a non-existent or non-
3052            accessible file (but not the return code). There is a new option called
3053            -q that suppresses the output of matching lines, which was what -s was
3054            previously doing.
3056        (p) Added --include and --exclude options to specify files for inclusion
3057            and exclusion when recursing.
3059    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
3060        Hopefully, it now does.
3062    12. Missing cast in pcre_study().
3064    13. Added an "uninstall" target to the makefile.
3066    14. Replaced "extern" in the function prototypes in Makefile.in with
3067        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
3068        world, but is set differently for Windows.
3070    15. Added a second compiling function called pcre_compile2(). The only
3071        difference is that it has an extra argument, which is a pointer to an
3072        integer error code. When there is a compile-time failure, this is set
3073        non-zero, in addition to the error test pointer being set to point to an
3074        error message. The new argument may be NULL if no error number is required
3075        (but then you may as well call pcre_compile(), which is now just a
3076        wrapper). This facility is provided because some applications need a
3077        numeric error indication, but it has also enabled me to tidy up the way
3078        compile-time errors are handled in the POSIX wrapper.
3080    16. Added VPATH=.libs to the makefile; this should help when building with one
3081        prefix path and installing with another. (Or so I'm told by someone who
3082        knows more about this stuff than I do.)
3084    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
3085        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
3086        match everything, including newlines. This is not POSIX-compatible, but
3087        somebody wanted the feature. From pcretest it can be activated by using
3088        both the P and the s flags.
3090    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
3092    19. libpcre.pc was being incorrectly installed as executable.
3094    20. A couple of places in pcretest check for end-of-line by looking for '\n';
3095        it now also looks for '\r' so that it will work unmodified on Windows.
3097    21. Added Google's contributed C++ wrapper to the distribution.
3099    22. Added some untidy missing memory free() calls in pcretest, to keep
3100        Electric Fence happy when testing.
3104    Version 5.0 13-Sep-04
3105    ---------------------
3107     1. Internal change: literal characters are no longer packed up into items
3108        containing multiple characters in a single byte-string. Each character
3109        is now matched using a separate opcode. However, there may be more than one
3110        byte in the character in UTF-8 mode.
3112     2. The pcre_callout_block structure has two new fields: pattern_position and
3113        next_item_length. These contain the offset in the pattern to the next match
3114        item, and its length, respectively.
3116     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
3117        insertion of callouts before each pattern item. Added the /C option to
3118        pcretest to make use of this.
3120     4. On the advice of a Windows user, the lines
3122          #if defined(_WIN32) || defined(WIN32)
3123          _setmode( _fileno( stdout ), 0x8000 );
3124          #endif  /* defined(_WIN32) || defined(WIN32) */
3126        have been added to the source of pcretest. This apparently does useful
3127        magic in relation to line terminators.
3129     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
3130        for the benefit of those environments where the "b" makes a difference.
3132     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
3133        to know about it. I have put a hack into configure.in that adds in code
3134        to set GCC=yes if CC=icc. This seems to end up at a point in the
3135        generated configure script that is early enough to affect the setting of
3136        compiler options, which is what is needed, but I have no means of testing
3137        whether it really works. (The user who reported this had patched the
3138        generated configure script, which of course I cannot do.)
3140        LATER: After change 22 below (new libtool files), the configure script
3141        seems to know about icc (and also ecc). Therefore, I have commented out
3142        this hack in configure.in.
3144     7. Added support for pkg-config (2 patches were sent in).
3146     8. Negated POSIX character classes that used a combination of internal tables
3147        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
3148        [[:^ascii]]. Typically, they would match almost any characters. The other
3149        POSIX classes were not broken in this way.
3151     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
3152        to find the match, as PCRE was deluded into thinking that the match had to
3153        start at the start point or following a newline. The same bug applied to
3154        patterns with negative forward assertions or any backward assertions
3155        preceding ".*" at the start, unless the pattern required a fixed first
3156        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
3158    10. In UTF-8 mode, when moving forwards in the subject after a failed match
3159        starting at the last subject character, bytes beyond the end of the subject
3160        string were read.
3162    11. Renamed the variable "class" as "classbits" to make life easier for C++
3163        users. (Previously there was a macro definition, but it apparently wasn't
3164        enough.)
3166    12. Added the new field "tables" to the extra data so that tables can be passed
3167        in at exec time, or the internal tables can be re-selected. This allows
3168        a compiled regex to be saved and re-used at a later time by a different
3169        program that might have everything at different addresses.
3171    13. Modified the pcre-config script so that, when run on Solaris, it shows a
3172        -R library as well as a -L library.
3174    14. The debugging options of pcretest (-d on the command line or D on a
3175        pattern) showed incorrect output for anything following an extended class
3176        that contained multibyte characters and which was followed by a quantifier.
3178    15. Added optional support for general category Unicode character properties
3179        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
3180        support. It adds about 90K to the size of the library. The meanings of the
3181        inbuilt class escapes such as \d and \s have NOT been changed.
3183    16. Updated pcredemo.c to include calls to free() to release the memory for the
3184        compiled pattern.
3186    17. The generated file chartables.c was being created in the source directory
3187        instead of in the building directory. This caused the build to fail if the
3188        source directory was different from the building directory, and was
3189        read-only.
3191    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
3192        file. No doubt somebody will tell me if they don't make sense... Also added
3193        Dan Mooney's comments about building on OpenVMS.
3195    19. Added support for partial matching via the PCRE_PARTIAL option for
3196        pcre_exec() and the \P data escape in pcretest.
3198    20. Extended pcretest with 3 new pattern features:
3200        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
3201              write the compiled pattern to the file whose name is "rest-of-line".
3202              This is a straight binary dump of the data, with the saved pointer to
3203              the character tables forced to be NULL. The study data, if any, is
3204              written too. After writing, pcretest reads a new pattern.
3206        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
3207              compiled pattern from the given file. There must not be any
3208              occurrences of "<" in the file name (pretty unlikely); if there are,
3209              pcretest will instead treat the initial "<" as a pattern delimiter.
3210              After reading in the pattern, pcretest goes on to read data lines as
3211              usual.
3213        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
3214              and 16-bit fields in a compiled pattern, to simulate a pattern that
3215              was compiled on a host of opposite endianness.
3217    21. The pcre-exec() function can now cope with patterns that were compiled on
3218        hosts of opposite endianness, with this restriction:
3220          As for any compiled expression that is saved and used later, the tables
3221          pointer field cannot be preserved; the extra_data field in the arguments
3222          to pcre_exec() should be used to pass in a tables address if a value
3223          other than the default internal tables were used at compile time.
3225    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
3226        now diagnosed as an error. Previously, most of the time, a negative number
3227        would have been treated as zero, but if in addition "ovector" was passed as
3228        NULL, a crash could occur.
3230    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
3231        new versions from the libtool 1.5 distribution (the last one is a copy of
3232        a file called libtool.m4). This seems to have fixed the need to patch
3233        "configure" to support Darwin 1.3 (which I used to do). However, I still
3234        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
3235        workstation).
3237    24. Changed the PCRE licence to be the more standard "BSD" licence.
3240    Version 4.5 01-Dec-03
3241    ---------------------
3243     1. There has been some re-arrangement of the code for the match() function so
3244        that it can be compiled in a version that does not call itself recursively.
3245        Instead, it keeps those local variables that need separate instances for
3246        each "recursion" in a frame on the heap, and gets/frees frames whenever it
3247        needs to "recurse". Keeping track of where control must go is done by means
3248        of setjmp/longjmp. The whole thing is implemented by a set of macros that
3249        hide most of the details from the main code, and operates only if
3250        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
3251        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
3252        operating.
3254        To make it easier for callers to provide specially tailored get/free
3255        functions for this usage, two new functions, pcre_stack_malloc, and
3256        pcre_stack_free, are used. They are always called in strict stacking order,
3257        and the size of block requested is always the same.
3259        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
3260        PCRE has been compiled to use the stack or the heap for recursion. The
3261        -C option of pcretest uses this to show which version is compiled.
3263        A new data escape \S, is added to pcretest; it causes the amounts of store
3264        obtained and freed by both kinds of malloc/free at match time to be added
3265        to the output.
3267     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
3268        what's available on my current Linux desktop machine.
3270     3. When matching a UTF-8 string, the test for a valid string at the start has
3271        been extended. If start_offset is not zero, PCRE now checks that it points
3272        to a byte that is the start of a UTF-8 character. If not, it returns
3273        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
3274        this is necessary because there may be backward assertions in the pattern.
3275        When matching the same subject several times, it may save resources to use
3276        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
3278     4. The code for checking the validity of UTF-8 strings has been tightened so
3279        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
3280        containing "overlong sequences".
3282     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
3283        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
3284        should have been "&", but it just so happened that all the cases this let
3285        through by mistake were picked up later in the function.
3287     6. I had used a variable called "isblank" - this is a C99 function, causing
3288        some compilers to warn. To avoid this, I renamed it (as "blankclass").
3290     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
3291        prompting; (b) run "./pcretest /dev/null" at the start of the test script
3292        so the version is shown; (c) stop "make test" echoing "./RunTest".
3294     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
3296     9. The prototype for memmove() for systems that don't have it was using
3297        size_t, but the inclusion of the header that defines size_t was later. I've
3298        moved the #includes for the C headers earlier to avoid this.
3300    10. Added some adjustments to the code to make it easier to compiler on certain
3301        special systems:
3303          (a) Some "const" qualifiers were missing.
3304          (b) Added the macro EXPORT before all exported functions; by default this
3305              is defined to be empty.
3306          (c) Changed the dftables auxiliary program (that builds chartables.c) so
3307              that it reads its output file name as an argument instead of writing
3308              to the standard output and assuming this can be redirected.
3310    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
3311        class containing characters with values greater than 255, PCRE compilation
3312        went into a loop.
3314    12. A recursive reference to a subpattern that was within another subpattern
3315        that had a minimum quantifier of zero caused PCRE to crash. For example,
3316        (x(y(?2))z)? provoked this bug with a subject that got as far as the
3317        recursion. If the recursively-called subpattern itself had a zero repeat,
3318        that was OK.
3320    13. In pcretest, the buffer for reading a data line was set at 30K, but the
3321        buffer into which it was copied (for escape processing) was still set at
3322        1024, so long lines caused crashes.
3324    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
3325        "internal error: code overflow...". This applied to any character class
3326        that was followed by a possessive quantifier.
3328    15. Modified the Makefile to add libpcre.la as a prerequisite for
3329        libpcreposix.la because I was told this is needed for a parallel build to
3330        work.
3332    16. If a pattern that contained .* following optional items at the start was
3333        studied, the wrong optimizing data was generated, leading to matching
3334        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
3335        matching string must start with a or b or c. The correct conclusion for
3336        this pattern is that a match can start with any character.
3339    Version 4.4 13-Aug-03
3340    ---------------------
3342     1. In UTF-8 mode, a character class containing characters with values between
3343        127 and 255 was not handled correctly if the compiled pattern was studied.
3344        In fixing this, I have also improved the studying algorithm for such
3345        classes (slightly).
3347     2. Three internal functions had redundant arguments passed to them. Removal
3348        might give a very teeny performance improvement.
3350     3. Documentation bug: the value of the capture_top field in a callout is *one
3351        more than* the number of the hightest numbered captured substring.
3353     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
3354        in incorrectly linking with a previously installed version. They now link
3355        explicitly with libpcre.la.
3357     5. configure.in no longer needs to recognize Cygwin specially.
3359     6. A problem in pcre.in for Windows platforms is fixed.
3361     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
3362        pcretest, it used to include the size of the study block as part of its
3363        output. Unfortunately, the structure contains a field that has a different
3364        size on different hardware architectures. This meant that the tests that
3365        showed this size failed. As the block is currently always of a fixed size,
3366        this information isn't actually particularly useful in pcretest output, so
3367        I have just removed it.
3369     8. Three pre-processor statements accidentally did not start in column 1.
3370        Sadly, there are *still* compilers around that complain, even though
3371        standard C has not required this for well over a decade. Sigh.
3373     9. In pcretest, the code for checking callouts passed small integers in the
3374        callout_data field, which is a void * field. However, some picky compilers
3375        complained about the casts involved for this on 64-bit systems. Now
3376        pcretest passes the address of the small integer instead, which should get
3377        rid of the warnings.
3379    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
3380        both compile and run time, and gives an error if an invalid UTF-8 sequence
3381        is found. There is a option for disabling this check in cases where the
3382        string is known to be correct and/or the maximum performance is wanted.
3384    11. In response to a bug report, I changed one line in Makefile.in from
3386            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
3387        to
3388            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
3390        to look similar to other lines, but I have no way of telling whether this
3391        is the right thing to do, as I do not use Windows. No doubt I'll get told
3392        if it's wrong...
3395    Version 4.3 21-May-03
3396    ---------------------
3398    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
3399       Makefile.
3401    2. Some refactoring to improve the quality of the code:
3403       (i)   The utf8_table... variables are now declared "const".
3405       (ii)  The code for \cx, which used the "case flipping" table to upper case
3406             lower case letters, now just substracts 32. This is ASCII-specific,
3407             but the whole concept of \cx is ASCII-specific, so it seems
3408             reasonable.
3410       (iii) PCRE was using its character types table to recognize decimal and
3411             hexadecimal digits in the pattern. This is silly, because it handles
3412             only 0-9, a-f, and A-F, but the character types table is locale-
3413             specific, which means strange things might happen. A private
3414             table is now used for this - though it costs 256 bytes, a table is
3415             much faster than multiple explicit tests. Of course, the standard
3416             character types table is still used for matching digits in subject
3417             strings against \d.
3419       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
3420             ending in _t are). So I've renamed it as ESC_tee.
3422    3. The first argument for regexec() in the POSIX wrapper should have been
3423       defined as "const".
3425    4. Changed pcretest to use malloc() for its buffers so that they can be
3426       Electric Fenced for debugging.
3428    5. There were several places in the code where, in UTF-8 mode, PCRE would try
3429       to read one or more bytes before the start of the subject string. Often this
3430       had no effect on PCRE's behaviour, but in some circumstances it could
3431       provoke a segmentation fault.
3433    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
3434       to try to read one or more bytes before the start of the subject string.
3436    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
3437       UTF-8 support could misbehave in various ways if the subject string
3438       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
3439       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
3440       back over UTF-8 characters.)
3443    Version 4.2 14-Apr-03
3444    ---------------------
3446    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
3448    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
3449         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
3450         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
3451         [WIN_PREFIX]: new variable, "cyg" for Cygwin
3452         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
3453           and BUILD_EXEEXT
3454         Note: automatic setting of the BUILD variables is not yet working
3455         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
3456           compile-time but not at link-time
3457         [LINK]: use for linking executables only
3458         make different versions for Windows and non-Windows
3459         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
3460           libraries
3461         [LINK_FOR_BUILD]: new variable
3462         [OBJEXT]: use throughout
3463         [EXEEXT]: use throughout
3464         <winshared>: new target
3465         <wininstall>: new target
3466         <dftables.o>: use native compiler
3467         <dftables>: use native linker
3468         <install>: handle Windows platform correctly
3469         <clean>: ditto
3470         <check>: ditto
3471         copy DLL to top builddir before testing
3473       As part of these changes, -no-undefined was removed again. This was reported
3474       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
3475       in any case.
3477    3. Some tidies to get rid of compiler warnings:
3479       . In the match_data structure, match_limit was an unsigned long int, whereas
3480         match_call_count was an int. I've made them both unsigned long ints.
3482       . In pcretest the fact that a const uschar * doesn't automatically cast to
3483         a void * provoked a warning.
3485       . Turning on some more compiler warnings threw up some "shadow" variables
3486         and a few more missing casts.
3488    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
3489       option, a class that contained a single character with a value between 128
3490       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
3492    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
3493       option, a class that contained several characters, but with at least one
3494       whose value was between 128 and 255 caused PCRE to crash.
3497    Version 4.1 12-Mar-03
3498    ---------------------
3500    1. Compiling with gcc -pedantic found a couple of places where casts were
3501    needed, and a string in dftables.c that was longer than standard compilers are
3502    required to support.
3504    2. Compiling with Sun's compiler found a few more places where the code could
3505    be tidied up in order to avoid warnings.
3507    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
3508    first of these names is deprecated in the latest Autoconf in favour of the name
3509    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
3510    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
3511    analogy I have changed it to CFLAGS_FOR_BUILD.
3513    4. Added -no-undefined to the linking command in the Makefile, because this is
3514    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
3515    linking step for the pcreposix library.
3517    5. PCRE was failing to diagnose the case of two named groups with the same
3518    name.
3520    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
3521    literal character that is needed in the subject for a match, and scans along to
3522    ensure that it is present before embarking on the full matching process. This
3523    saves time in cases of nested unlimited repeats that are never going to match.
3524    Problem: the scan can take a lot of time if the subject is very long (e.g.
3525    megabytes), thus penalizing straightforward matches. It is now done only if the
3526    amount of subject to be scanned is less than 1000 bytes.
3528    7. A lesser problem with the same optimization is that it was recording the
3529    first character of an anchored pattern as "needed", thus provoking a search
3530    right along the subject, even when the first match of the pattern was going to
3531    fail. The "needed" character is now not set for anchored patterns, unless it
3532    follows something in the pattern that is of non-fixed length. Thus, it still
3533    fulfils its original purpose of finding quick non-matches in cases of nested
3534    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
3537    Version 4.0 17-Feb-03
3538    ---------------------
3540    1. If a comment in an extended regex that started immediately after a meta-item
3541    extended to the end of string, PCRE compiled incorrect data. This could lead to
3542    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
3544    2. Moved to autoconf 2.53 and libtool 1.4.2.
3546    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
3547    the special perltest8 script is no longer needed - all the tests can be run
3548    from a single perltest script.
3550    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
3551    by \s. It has now been removed in PCRE. This means it isn't recognized as
3552    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
3553    class [:space:] *does* include VT, thereby creating a mess.
3555    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
3556    space and tab.
3558    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
3559    its new features into the main test script, reducing the number of scripts.
3561    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
3562    were backward compatible, and made the (?i) apply to the whole pattern, as if
3563    /i were given. Now it behaves more logically, and applies the option setting
3564    only to what follows. PCRE has been changed to follow suit. However, if it
3565    finds options settings right at the start of the pattern, it extracts them into
3566    the global options, as before. Thus, they show up in the info data.
3568    8. Added support for the \Q...\E escape sequence. Characters in between are
3569    treated as literals. This is slightly different from Perl in that $ and @ are
3570    also handled as literals inside the quotes. In Perl, they will cause variable
3571    interpolation. Note the following examples:
3573        Pattern            PCRE matches      Perl matches
3575        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
3576        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
3577        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
3579    For compatibility with Perl, \Q...\E sequences are recognized inside character
3580    classes as well as outside them.
3582    9. Re-organized 3 code statements in pcretest to avoid "overflow in
3583    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
3584    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
3585    signed/unsigned warnings.
3587    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o