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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.2 01-May-07  Version 8.31
5    -----------------------------
7    1.  Fixing a wrong JIT test case and some compiler warnings.
9    2.  Removed a bashism from the RunTest script.
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
36    6.  When matching is performed using JIT-compiled code, the flag bit
37        PCRE_EXTRA_USED_JIT is set in the pcre_extra block and can be tested by the
38        caller. This bit is checked by pcretest if JIT is requested by /S++ or -s++
39        (instead of just /S+ or -s+) and the text "(JIT)" added to the output if
40        the bit is set.
43    Version 8.30 04-February-2012
44    -----------------------------
46    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
47        name is defined in ctype.h.
49    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
50        only in quite long subpatterns.
52    3.  Removed the function pcre_info(), which has been obsolete and deprecated
53        since it was replaced by pcre_fullinfo() in February 2000.
55    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
56        match a (*MARK), and the match failed at the start of the subject, a
57        reference to memory before the start of the subject could occur. This bug
58        was introduced by fix 17 of release 8.21.
60    5.  A reference to an unset group with zero minimum repetition was giving
61        totally wrong answers (in non-JavaScript-compatibility mode). For example,
62        /(another)?(\1?)test/ matched against "hello world test". This bug was
63        introduced in release 8.13.
65    6.  Add support for 16-bit character strings (a large amount of work involving
66        many changes and refactorings).
68    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
69        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
70        from a file.
72    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
73        rounding is not applied in this particular case).
75    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
76        if they appear, or are escaped, in patterns.
78    10. Get rid of a number of -Wunused-but-set-variable warnings.
80    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
81        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
82        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
83        also returns the mark "x". This bug applied to capturing parentheses,
84        non-capturing parentheses, and atomic parentheses. It also applied to some
85        assertions.
87    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
88        information out of configure.ac instead of relying on pcre.h.generic, which
89        is not stored in the repository.
91    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
92        -lreadline.
94    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
96    15. Applied Graycode's patch to put the top-level frame on the stack rather
97        than the heap when not using the stack for recursion. This gives a
98        performance improvement in many cases when recursion is not deep.
100    16. Experimental code added to "pcretest -C" to output the stack frame size.
103    Version 8.21 12-Dec-2011
104    ------------------------
106    1.  Updating the JIT compiler.
108    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
109        are added as well.
111    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
112        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
113        calling _pcre_jit_exec. Some extra comments are added.
115    4.  (*MARK) settings inside atomic groups that do not contain any capturing
116        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
117        was introduced by change 18 for 8.20.
119    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
120        ECMA-262 standard.
122    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
123        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
124        This bug was probably introduced by change 9 of 8.13.
126    7.  While fixing 6 above, I noticed that a number of other items were being
127        incorrectly rejected as "not fixed length". This arose partly because newer
128        opcodes had not been added to the fixed-length checking code. I have (a)
129        corrected the bug and added tests for these items, and (b) arranged for an
130        error to occur if an unknown opcode is encountered while checking for fixed
131        length instead of just assuming "not fixed length". The items that were
132        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
133        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
134        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
136    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
137        being incorrectly compiled and would have given unpredicatble results.
139    9.  A possessively repeated subpattern with minimum repeat count greater than
140        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
141        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
142        the first (A) could occur when it should not.
144    10. Add a cast and remove a redundant test from the code.
146    11. JIT should use pcre_malloc/pcre_free for allocation.
148    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
149        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
150        is anything other than /usr, -L is still shown).
152    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
154    14. Perl does not support \N without a following name in a [] class; PCRE now
155        also gives an error.
157    15. If a forward reference was repeated with an upper limit of around 2000,
158        it caused the error "internal error: overran compiling workspace". The
159        maximum number of forward references (including repeats) was limited by the
160        internal workspace, and dependent on the LINK_SIZE. The code has been
161        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
162        the default depends on LINK_SIZE. There is a new upper limit (for safety)
163        of around 200,000 forward references. While doing this, I also speeded up
164        the filling in of repeated forward references.
166    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
167        incorrectly expecting the subject to contain another "a" after the start.
169    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
170        in the match, the SKIP should be ignored. This was not happening; instead
171        the SKIP was being treated as NOMATCH. For patterns such as
172        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
173        tested.
175    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
176        now much more compatible with Perl, in particular in cases where the result
177        is a non-match for a non-anchored pattern. For example, if
178        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
179        "m", where previously it did not return a name. A side effect of this
180        change is that for partial matches, the last encountered mark name is
181        returned, as for non matches. A number of tests that were previously not
182        Perl-compatible have been moved into the Perl-compatible test files. The
183        refactoring has had the pleasing side effect of removing one argument from
184        the match() function, thus reducing its stack requirements.
186    19. If the /S+ option was used in pcretest to study a pattern using JIT,
187        subsequent uses of /S (without +) incorrectly behaved like /S+.
189    21. Retrieve executable code size support for the JIT compiler and fixing
190        some warnings.
192    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
193        not work when the shorter character appeared right at the end of the
194        subject string.
196    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
197        systems.
199    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
200        output it when the /M option is used in pcretest.
202    25. The CheckMan script was not being included in the distribution. Also, added
203        an explicit "perl" to run Perl scripts from the PrepareRelease script
204        because this is reportedly needed in Windows.
206    26. If study data was being save in a file and studying had not found a set of
207        "starts with" bytes for the pattern, the data written to the file (though
208        never used) was taken from uninitialized memory and so caused valgrind to
209        complain.
211    27. Updated RunTest.bat as provided by Sheri Pierce.
213    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
215    29. Computation of memory usage for the table of capturing group names was
216        giving an unnecessarily large value.
219    Version 8.20 21-Oct-2011
220    ------------------------
222    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
223        a POSIX class. After further experiments with Perl, which convinced me that
224        Perl has bugs and confusions, a closing square bracket is no longer allowed
225        in a POSIX name. This bug also affected patterns with classes that started
226        with full stops.
228    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
229        captured substring, but while checking the failing first alternative,
230        substring 1 is temporarily captured. If the output vector supplied to
231        pcre_exec() was not big enough for this capture, the yield of the function
232        was still zero ("insufficient space for captured substrings"). This cannot
233        be totally fixed without adding another stack variable, which seems a lot
234        of expense for a edge case. However, I have improved the situation in cases
235        such as /(a)(b)x|abc/ matched against "abc", where the return code
236        indicates that fewer than the maximum number of slots in the ovector have
237        been set.
239    3.  Related to (2) above: when there are more back references in a pattern than
240        slots in the output vector, pcre_exec() uses temporary memory during
241        matching, and copies in the captures as far as possible afterwards. It was
242        using the entire output vector, but this conflicts with the specification
243        that only 2/3 is used for passing back captured substrings. Now it uses
244        only the first 2/3, for compatibility. This is, of course, another edge
245        case.
247    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
248        main code base, and can be used by building with --enable-jit. When this is
249        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
250        runtime --no-jit option is given.
252    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
253        ovector, the return from the function was zero, implying that there were
254        other matches that did not fit. The correct "exactly full" value is now
255        returned.
257    6.  If a subpattern that was called recursively or as a subroutine contained
258        (*PRUNE) or any other control that caused it to give a non-standard return,
259        invalid errors such as "Error -26 (nested recursion at the same subject
260        position)" or even infinite loops could occur.
262    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
263        computing the minimum length on reaching *ACCEPT, and so ended up with the
264        wrong value of 1 rather than 0. Further investigation indicates that
265        computing a minimum subject length in the presence of *ACCEPT is difficult
266        (think back references, subroutine calls), and so I have changed the code
267        so that no minimum is registered for a pattern that contains *ACCEPT.
269    8.  If (*THEN) was present in the first (true) branch of a conditional group,
270        it was not handled as intended. [But see 16 below.]
272    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
273        Sheri Pierce.
275    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
276        the first byte in a match must be "a".
278    11. Change 17 for 8.13 increased the recursion depth for patterns like
279        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
280        pattern contains any instances of (*THEN). If it does not, the old
281        optimizations are restored. It would be nice to do this on a per-group
282        basis, but at the moment that is not feasible.
284    12. In some environments, the output of pcretest -C is CRLF terminated. This
285        broke RunTest's code that checks for the link size. A single white space
286        character after the value is now allowed for.
288    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
289        For "fr", it uses the Windows-specific input and output files.
291    14. If (*THEN) appeared in a group that was called recursively or as a
292        subroutine, it did not work as intended. [But see next item.]
294    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
295        pattern fragments (but not containing any | characters). If A and B are
296        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
297        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
298        D. In other words, Perl considers parentheses that do not contain any |
299        characters to be part of a surrounding alternative, whereas PCRE was
300        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
301        differently. PCRE now behaves in the same way as Perl, except in the case
302        of subroutine/recursion calls such as (?1) which have in any case always
303        been different (but PCRE had them first :-).
305    16. Related to 15 above: Perl does not treat the | in a conditional group as
306        creating alternatives. Such a group is treated in the same way as an
307        ordinary group without any | characters when processing (*THEN). PCRE has
308        been changed to match Perl's behaviour.
310    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
311        RunGrepTest script failed.
313    18. Change 22 for version 13 caused atomic groups to use more stack. This is
314        inevitable for groups that contain captures, but it can lead to a lot of
315        stack use in large patterns. The old behaviour has been restored for atomic
316        groups that do not contain any capturing parentheses.
318    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
319        suppress the check for a minimum subject length at run time. (If it was
320        given to pcre_exec() or pcre_dfa_exec() it did work.)
322    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
323        fail to work when decoding hex characters in data strings in EBCDIC
324        environments.
326    21. It appears that in at least one Mac OS environment, the isxdigit() function
327        is implemented as a macro that evaluates to its argument more than once,
328        contravening the C 90 Standard (I haven't checked a later standard). There
329        was an instance in pcretest which caused it to go wrong when processing
330        \x{...} escapes in subject strings. The has been rewritten to avoid using
331        things like p++ in the argument of isxdigit().
334    Version 8.13 16-Aug-2011
335    ------------------------
337    1.  The Unicode data tables have been updated to Unicode 6.0.0.
339    2.  Two minor typos in pcre_internal.h have been fixed.
341    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
342        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
343        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
345    4.  There were a number of related bugs in the code for matching backrefences
346        caselessly in UTF-8 mode when codes for the characters concerned were
347        different numbers of bytes. For example, U+023A and U+2C65 are an upper
348        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
349        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
350        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
351        2-byte code at the end of the subject (it thought there wasn't enough data
352        left).
354    5.  Comprehensive information about what went wrong is now returned by
355        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
356        as the output vector has at least 2 elements. The offset of the start of
357        the failing character and a reason code are placed in the vector.
359    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
360        now returned is for the first byte of the failing character, instead of the
361        last byte inspected. This is an incompatible change, but I hope it is small
362        enough not to be a problem. It makes the returned offset consistent with
363        pcre_exec() and pcre_dfa_exec().
365    7.  pcretest now gives a text phrase as well as the error number when
366        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
367        failure, the offset and reason code are output.
369    8.  When \R was used with a maximizing quantifier it failed to skip backwards
370        over a \r\n pair if the subsequent match failed. Instead, it just skipped
371        back over a single character (\n). This seems wrong (because it treated the
372        two characters as a single entity when going forwards), conflicts with the
373        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
374        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
375        has been changed.
377    9.  Some internal refactoring has changed the processing so that the handling
378        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
379        time (the PCRE_DOTALL option was changed this way some time ago: version
380        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
381        which was always a bit of a fudge. It also means that there is one less
382        argument for the match() function, which reduces its stack requirements
383        slightly. This change also fixes an incompatibility with Perl: the pattern
384        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
386    10. More internal refactoring has drastically reduced the number of recursive
387        calls to match() for possessively repeated groups such as (abc)++ when
388        using pcre_exec().
390    11. While implementing 10, a number of bugs in the handling of groups were
391        discovered and fixed:
393        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
394        (a|)*(?1) gave a compile-time internal error.
395        ((a|)+)+  did not notice that the outer group could match an empty string.
396        (^a|^)+   was not marked as anchored.
397        (.*a|.*)+ was not marked as matching at start or after a newline.
399    12. Yet more internal refactoring has removed another argument from the match()
400        function. Special calls to this function are now indicated by setting a
401        value in a variable in the "match data" data block.
403    13. Be more explicit in pcre_study() instead of relying on "default" for
404        opcodes that mean there is no starting character; this means that when new
405        ones are added and accidentally left out of pcre_study(), testing should
406        pick them up.
408    14. The -s option of pcretest has been documented for ages as being an old
409        synonym of -m (show memory usage). I have changed it to mean "force study
410        for every regex", that is, assume /S for every regex. This is similar to -i
411        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
412        using it. It makes it easier to run collections of tests with and without
413        study enabled, and thereby test pcre_study() more easily. All the standard
414        tests are now run with and without -s (but some patterns can be marked as
415        "never study" - see 20 below).
417    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
418        restoration of the capturing data to the outer values was not happening
419        correctly.
421    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
422        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
423        pattern had matched an empty string, and so incorrectly returned a no
424        match.
426    17. There was optimizing code for the last branch of non-capturing parentheses,
427        and also for the obeyed branch of a conditional subexpression, which used
428        tail recursion to cut down on stack usage. Unfortunately, now that there is
429        the possibility of (*THEN) occurring in these branches, tail recursion is
430        no longer possible because the return has to be checked for (*THEN). These
431        two optimizations have therefore been removed. [But see 8.20/11 above.]
433    18. If a pattern containing \R was studied, it was assumed that \R always
434        matched two bytes, thus causing the minimum subject length to be
435        incorrectly computed because \R can also match just one byte.
437    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
438        was incorrectly computed.
440    20. If /S is present twice on a test pattern in pcretest input, it now
441        *disables* studying, thereby overriding the use of -s on the command line
442        (see 14 above). This is necessary for one or two tests to keep the output
443        identical in both cases.
445    21. When (*ACCEPT) was used in an assertion that matched an empty string and
446        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
448    22. When an atomic group that contained a capturing parenthesis was
449        successfully matched, but the branch in which it appeared failed, the
450        capturing was not being forgotten if a higher numbered group was later
451        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
452        group 1 to "a", when in fact it should be unset. This applied to multi-
453        branched capturing and non-capturing groups, repeated or not, and also to
454        positive assertions (capturing in negative assertions does not happen
455        in PCRE) and also to nested atomic groups.
457    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
458        subject after a captured substring, to make it easier to tell which of a
459        number of identical substrings has been captured.
461    24. The way atomic groups are processed by pcre_exec() has been changed so that
462        if they are repeated, backtracking one repetition now resets captured
463        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
464        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
465        "aaa". Previously, it would have been "a". As part of this code
466        refactoring, the way recursive calls are handled has also been changed.
468    25. If an assertion condition captured any substrings, they were not passed
469        back unless some other capturing happened later. For example, if
470        (?(?=(a))a) was matched against "a", no capturing was returned.
472    26. When studying a pattern that contained subroutine calls or assertions,
473        the code for finding the minimum length of a possible match was handling
474        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
475        group 1 called group 2 while simultaneously a separate group 2 called group
476        1). A stack overflow occurred in this case. I have fixed this by limiting
477        the recursion depth to 10.
479    27. Updated RunTest.bat in the distribution to the version supplied by Tom
480        Fortmann. This supports explicit test numbers on the command line, and has
481        argument validation and error reporting.
483    28. An instance of \X with an unlimited repeat could fail if at any point the
484        first character it looked at was a mark character.
486    29. Some minor code refactoring concerning Unicode properties and scripts
487        should reduce the stack requirement of match() slightly.
489    30. Added the '=' option to pcretest to check the setting of unused capturing
490        slots at the end of the pattern, which are documented as being -1, but are
491        not included in the return count.
493    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
494        compiled something random. Now it gives a compile-time error (as does
495        Perl).
497    32. A *MARK encountered during the processing of a positive assertion is now
498        recorded and passed back (compatible with Perl).
500    33. If --only-matching or --colour was set on a pcregrep call whose pattern
501        had alternative anchored branches, the search for a second match in a line
502        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
503        matched the line "0102" twice. The same bug affected patterns that started
504        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
505        twice.
507    34. Previously, PCRE did not allow quantification of assertions. However, Perl
508        does, and because of capturing effects, quantifying parenthesized
509        assertions may at times be useful. Quantifiers are now allowed for
510        parenthesized assertions.
512    35. A minor code tidy in pcre_compile() when checking options for \R usage.
514    36. \g was being checked for fancy things in a character class, when it should
515        just be a literal "g".
517    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
518        appearance of a nested POSIX class supersedes an apparent external class.
519        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
520        unescaped square brackets may also appear as part of class names. For
521        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
522        more like Perl. (But see 8.20/1 above.)
524    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
525        was because it thought it was \N{name}, which is not supported).
527    39. Add minix to OS list not supporting the -S option in pcretest.
529    40. PCRE tries to detect cases of infinite recursion at compile time, but it
530        cannot analyze patterns in sufficient detail to catch mutual recursions
531        such as ((?1))((?2)). There is now a runtime test that gives an error if a
532        subgroup is called recursively as a subpattern for a second time at the
533        same position in the subject string. In previous releases this might have
534        been caught by the recursion limit, or it might have run out of stack.
536    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
537        happen only once. PCRE was, however incorrectly giving a compile time error
538        "recursive call could loop indefinitely" because it cannot analyze the
539        pattern in sufficient detail. The compile time test no longer happens when
540        PCRE is compiling a conditional subpattern, but actual runaway loops are
541        now caught at runtime (see 40 above).
543    42. It seems that Perl allows any characters other than a closing parenthesis
544        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
545        has been changed to be the same.
547    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
548        as not to get warnings when autogen.sh is called. Also changed
549        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
551    44. To help people who use pcregrep to scan files containing exceedingly long
552        lines, the following changes have been made:
554        (a) The default value of the buffer size parameter has been increased from
555            8K to 20K. (The actual buffer used is three times this size.)
557        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
558            PCRE is built.
560        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
561            to be set at run time.
563        (d) Numerical values in pcregrep options can be followed by K or M, for
564            example --buffer-size=50K.
566        (e) If a line being scanned overflows pcregrep's buffer, an error is now
567            given and the return code is set to 2.
569    45. Add a pointer to the latest mark to the callout data block.
571    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
572        partial match of an empty string instead of no match. This was specific to
573        the use of ".".
575    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
576        complete match instead of a partial match. This bug was dependent on both
577        the PCRE_UTF8 and PCRE_DOTALL options being set.
579    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
580        starting byte set, because \b was not being ignored.
583    Version 8.12 15-Jan-2011
584    ------------------------
586    1.  Fixed some typos in the markup of the man pages, and wrote a script that
587        checks for such things as part of the documentation building process.
589    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
590        --match-limit and --recursion-limit options (added for 8.11). In
591        particular, this made one of the standard tests fail. (The integer value
592        went into the wrong half of a long int.)
594    3.  If the --colour option was given to pcregrep with -v (invert match), it
595        did strange things, either producing crazy output, or crashing. It should,
596        of course, ignore a request for colour when reporting lines that do not
597        match.
599    4.  Another pcregrep bug caused similar problems if --colour was specified with
600        -M (multiline) and the pattern match finished with a line ending.
602    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
603        matched in multiline mode, the following line was shown as part of the
604        match. This seems wrong, so I have changed it.
606    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
607        the check for further matches in the same line (so they could be coloured)
608        to overrun the end of the current line. If another match was found, it was
609        incorrectly shown (and then shown again when found in the next line).
611    7.  If pcregrep was compiled under Windows, there was a reference to the
612        function pcregrep_exit() before it was defined. I am assuming this was
613        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
614        reported by a user. I've moved the definition above the reference.
617    Version 8.11 10-Dec-2010
618    ------------------------
620    1.  (*THEN) was not working properly if there were untried alternatives prior
621        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
622        backtracked to try for "b" instead of moving to the next alternative branch
623        at the same level (in this case, to look for "c"). The Perl documentation
624        is clear that when (*THEN) is backtracked onto, it goes to the "next
625        alternative in the innermost enclosing group".
627    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
628        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
629        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
630        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
631        (*THEN).
633    3.  If \s appeared in a character class, it removed the VT character from
634        the class, even if it had been included by some previous item, for example
635        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
636        of \s, but is part of the POSIX "space" class.)
638    4.  A partial match never returns an empty string (because you can always
639        match an empty string at the end of the subject); however the checking for
640        an empty string was starting at the "start of match" point. This has been
641        changed to the "earliest inspected character" point, because the returned
642        data for a partial match starts at this character. This means that, for
643        example, /(?<=abc)def/ gives a partial match for the subject "abc"
644        (previously it gave "no match").
646    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
647        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
648        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
649        has an implication that the given string is incomplete (because a partial
650        match is preferred over a full match). For this reason, these items now
651        give a partial match in this situation. [Aside: previously, the one case
652        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
653        match rather than a full match, which was wrong by the old rules, but is
654        now correct.]
656    6.  There was a bug in the handling of #-introduced comments, recognized when
657        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
658        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
659        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
660        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
661        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
662        places in pcre_compile().
664    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
665        comments when looking ahead for named forward references to subpatterns,
666        the only newline sequence it recognized was NL. It now handles newlines
667        according to the set newline convention.
669    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
670        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
671        cater for a lack of strerror(). These oversights have been fixed.
673    9.  Added --match-limit and --recursion-limit to pcregrep.
675    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
677    11. When the -o option was used, pcregrep was setting a return code of 1, even
678        when matches were found, and --line-buffered was not being honoured.
680    12. Added an optional parentheses number to the -o and --only-matching options
681        of pcregrep.
683    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
684        can match an empty string. The code to do it in pcretest and pcredemo
685        needed fixing:
687        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
688            only one byte after an empty string match just before CRLF (this case
689            just got forgotten; "any" and "anycrlf" were OK).
691        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
692            mode when an empty string match preceded an ASCII character followed by
693            a non-ASCII character. (The code for advancing by one character rather
694            than one byte was nonsense.)
696        (c) The pcredemo.c sample program did not have any code at all to handle
697            the cases when CRLF is a valid newline sequence.
699    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
700        as a starting offset was within the subject string. There is now a new
701        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
702        negative or greater than the length of the string. In order to test this,
703        pcretest is extended to allow the setting of negative starting offsets.
705    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
706        starting offset points to the beginning of a UTF-8 character was
707        unnecessarily clumsy. I tidied it up.
709    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
710        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
712    17. Nobody had reported that the --include_dir option, which was added in
713        release 7.7 should have been called --include-dir (hyphen, not underscore)
714        for compatibility with GNU grep. I have changed it to --include-dir, but
715        left --include_dir as an undocumented synonym, and the same for
716        --exclude-dir, though that is not available in GNU grep, at least as of
717        release 2.5.4.
719    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
720        characters from a string of bytes) have been redefined so as not to use
721        loops, in order to improve performance in some environments. At the same
722        time, I abstracted some of the common code into auxiliary macros to save
723        repetition (this should not affect the compiled code).
725    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
726        compile-time error is now given if \c is not followed by an ASCII
727        character, that is, a byte less than 128. (In EBCDIC mode, the code is
728        different, and any byte value is allowed.)
730    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
731        START_OPTIMIZE option, which is now allowed at compile time - but just
732        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
733        to pcregrep and other applications that have no direct access to PCRE
734        options. The new /Y option in pcretest sets this option when calling
735        pcre_compile().
737    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
738        back references. Groups containing recursive back references were forced to
739        be atomic by that change, but in the case of named groups, the amount of
740        memory required was incorrectly computed, leading to "Failed: internal
741        error: code overflow". This has been fixed.
743    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
744        pcretest.c, to avoid build problems in some Borland environments.
747    Version 8.10 25-Jun-2010
748    ------------------------
750    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
751        THEN.
753    2.  (*ACCEPT) was not working when inside an atomic group.
755    3.  Inside a character class, \B is treated as a literal by default, but
756        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
757        causes the error). The code is unchanged, but I tidied the documentation.
759    4.  Inside a character class, PCRE always treated \R and \X as literals,
760        whereas Perl faults them if its -w option is set. I have changed PCRE so
761        that it faults them when PCRE_EXTRA is set.
763    5.  Added support for \N, which always matches any character other than
764        newline. (It is the same as "." when PCRE_DOTALL is not set.)
766    6.  When compiling pcregrep with newer versions of gcc which may have
767        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
768        declared with attribute warn_unused_result" were given. Just casting the
769        result to (void) does not stop the warnings; a more elaborate fudge is
770        needed. I've used a macro to implement this.
772    7.  Minor change to pcretest.c to avoid a compiler warning.
774    8.  Added four artifical Unicode properties to help with an option to make
775        \s etc use properties (see next item). The new properties are: Xan
776        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
778    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
779        use Unicode properties. (*UCP) at the start of a pattern can be used to set
780        this option. Modified pcretest to add /W to test this facility. Added
781        REG_UCP to make it available via the POSIX interface.
783    10. Added --line-buffered to pcregrep.
785    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
786        studied, and the match started with a letter with a code point greater than
787        127 whose first byte was different to the first byte of the other case of
788        the letter, the other case of this starting letter was not recognized
789        (#976).
791    12. If a pattern that was studied started with a repeated Unicode property
792        test, for example, \p{Nd}+, there was the theoretical possibility of
793        setting up an incorrect bitmap of starting bytes, but fortunately it could
794        not have actually happened in practice until change 8 above was made (it
795        added property types that matched character-matching opcodes).
797    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
798        possible starting bytes for non-anchored patterns.
800    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
801        \R, and also a number of cases that involve Unicode properties, both
802        explicit and implicit when PCRE_UCP is set.
804    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
805        input, it could crash or give wrong results if characters with values
806        greater than 0xc0 were present in the subject string. (Detail: it assumed
807        UTF-8 input when processing these items.)
809    16. Added a lot of (int) casts to avoid compiler warnings in systems where
810        size_t is 64-bit (#991).
812    17. Added a check for running out of memory when PCRE is compiled with
813        --disable-stack-for-recursion (#990).
815    18. If the last data line in a file for pcretest does not have a newline on
816        the end, a newline was missing in the output.
818    19. The default pcre_chartables.c file recognizes only ASCII characters (values
819        less than 128) in its various bitmaps. However, there is a facility for
820        generating tables according to the current locale when PCRE is compiled. It
821        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
822        characters, are recognized by isspace() and therefore were getting set in
823        these tables, and indeed these tables seem to approximate to ISO 8859. This
824        caused a problem in UTF-8 mode when pcre_study() was used to create a list
825        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
826        which of course cannot start UTF-8 characters. I have changed the code so
827        that only real ASCII characters (less than 128) and the correct starting
828        bytes for UTF-8 encodings are set for characters greater than 127 when in
829        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
830        altogether.)
832    20. Added the /T option to pcretest so as to be able to run tests with non-
833        standard character tables, thus making it possible to include the tests
834        used for 19 above in the standard set of tests.
836    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
837        reference to a subpattern the other side of a comment that contains an
838        opening parenthesis caused either an internal compiling error, or a
839        reference to the wrong subpattern.
842    Version 8.02 19-Mar-2010
843    ------------------------
845    1.  The Unicode data tables have been updated to Unicode 5.2.0.
847    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
848        configured.
850    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
851        original author of that file, following a query about its status.
853    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
854        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
856    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
857        quantifier applied to a forward-referencing subroutine call, could compile
858        incorrect code or give the error "internal error: previously-checked
859        referenced subpattern not found".
861    6.  Both MS Visual Studio and Symbian OS have problems with initializing
862        variables to point to external functions. For these systems, therefore,
863        pcre_malloc etc. are now initialized to local functions that call the
864        relevant global functions.
866    7.  There were two entries missing in the vectors called coptable and poptable
867        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
868        I've fixed the data, and added a kludgy way of testing at compile time that
869        the lengths are correct (equal to the number of opcodes).
871    8.  Following on from 7, I added a similar kludge to check the length of the
872        eint vector in pcreposix.c.
874    9.  Error texts for pcre_compile() are held as one long string to avoid too
875        much relocation at load time. To find a text, the string is searched,
876        counting zeros. There was no check for running off the end of the string,
877        which could happen if a new error number was added without updating the
878        string.
880    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
882    11. \K was not working if it appeared in an atomic group or in a group that
883        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
884        \K is "not well defined" if used in an assertion. PCRE now accepts it if
885        the assertion is positive, but not if it is negative.
887    12. Change 11 fortuitously reduced the size of the stack frame used in the
888        "match()" function of pcre_exec.c by one pointer. Forthcoming
889        implementation of support for (*MARK) will need an extra pointer on the
890        stack; I have reserved it now, so that the stack frame size does not
891        decrease.
893    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
894        item in branch that calls a recursion is a subroutine call - as in the
895        second branch in the above example - was incorrectly given the compile-
896        time error "recursive call could loop indefinitely" because pcre_compile()
897        was not correctly checking the subroutine for matching a non-empty string.
899    14. The checks for overrunning compiling workspace could trigger after an
900        overrun had occurred. This is a "should never occur" error, but it can be
901        triggered by pathological patterns such as hundreds of nested parentheses.
902        The checks now trigger 100 bytes before the end of the workspace.
904    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
907    Version 8.01 19-Jan-2010
908    ------------------------
910    1.  If a pattern contained a conditional subpattern with only one branch (in
911        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
912        computed the wrong minimum data length (which is of course zero for such
913        subpatterns). This could cause incorrect "no match" results.
915    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
916        the pattern is reset in the first branch, pcre_compile() failed with
917        "internal error: code overflow at offset...". This happened only when
918        the reset was to the original external option setting. (An optimization
919        abstracts leading options settings into an external setting, which was the
920        cause of this.)
922    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
923        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
924        assertion pattern did not match (meaning that the assertion was true), it
925        was incorrectly treated as false if the SKIP had been reached during the
926        matching. This also applied to assertions used as conditions.
928    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
929        assertion subpattern, including such a pattern used as a condition,
930        unpredictable results occurred, instead of the error return
933    5.  The C++ GlobalReplace function was not working like Perl for the special
934        situation when an empty string is matched. It now does the fancy magic
935        stuff that is necessary.
937    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
938        removed. (These were left over from very, very early versions of PCRE.)
940    7.  Some cosmetic changes to the code to make life easier when compiling it
941        as part of something else:
943        (a) Change DEBUG to PCRE_DEBUG.
945        (b) In pcre_compile(), rename the member of the "branch_chain" structure
946            called "current" as "current_branch", to prevent a collision with the
947            Linux macro when compiled as a kernel module.
949        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
950            prevent a collision with the Linux macro when compiled as a kernel
951            module.
953    8.  In pcre_compile() there are some checks for integer overflows that used to
954        cast potentially large values to (double). This has been changed to that
955        when building, a check for int64_t is made, and if it is found, it is used
956        instead, thus avoiding the use of floating point arithmetic. (There is no
957        other use of FP in PCRE.) If int64_t is not found, the fallback is to
958        double.
960    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
961        2005 (difference between two addresses compared to an unsigned value).
963    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
964        custom one, because of the following reported problem in Windows:
966          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
967              under Win32.
968          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
969              therefore missing the function definition.
970          - The compiler thus generates a "C" signature for the test function.
971          - The linker fails to find the "C" function.
972          - PCRE fails to configure if asked to do so against libbz2.
974    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
975        messages were output:
977          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
978          rerunning libtoolize, to keep the correct libtool macros in-tree.
979          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
981        I have done both of these things.
983    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
984        most of the time, it *can* run out if it is given a pattern that contains a
985        runaway infinite recursion. I updated the discussion in the pcrestack man
986        page.
988    13. Now that we have gone to the x.xx style of version numbers, the minor
989        version may start with zero. Using 08 or 09 is a bad idea because users
990        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
991        interpreted as invalid octal numbers. I've updated the previous comment in
992        configure.ac, and also added a check that gives an error if 08 or 09 are
993        used.
995    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
996        causing partial matching to fail when the end of the subject matched \W
997        in a UTF-8 pattern where \W was quantified with a minimum of 3.
999    15. There were some discrepancies between the declarations in pcre_internal.h
1000        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
1001        their definitions. The declarations used "const uschar *" and the
1002        definitions used USPTR. Even though USPTR is normally defined as "const
1003        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
1004        reported that: "This difference in casting confuses some C++ compilers, for
1005        example, SunCC recognizes above declarations as different functions and
1006        generates broken code for hbpcre." I have changed the declarations to use
1007        USPTR.
1009    16. GNU libtool is named differently on some systems. The autogen.sh script now
1010        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
1011        (FreeBSD).
1013    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
1014        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
1015        comment: "Figure out how to create a longlong from a string: strtoll and
1016        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
1017        instance, but it only takes 2 args instead of 3!"
1019    18. A subtle bug concerned with back references has been fixed by a change of
1020        specification, with a corresponding code fix. A pattern such as
1021        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
1022        refers, was giving matches when it shouldn't. For example, xa=xaaa would
1023        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
1024        same bug. Such groups have to be quantified to be useful, or contained
1025        inside another quantified group. (If there's no repetition, the reference
1026        can never match.) The problem arises because, having left the group and
1027        moved on to the rest of the pattern, a later failure that backtracks into
1028        the group uses the captured value from the final iteration of the group
1029        rather than the correct earlier one. I have fixed this in PCRE by forcing
1030        any group that contains a reference to itself to be an atomic group; that
1031        is, there cannot be any backtracking into it once it has completed. This is
1032        similar to recursive and subroutine calls.
1035    Version 8.00 19-Oct-09
1036    ----------------------
1038    1.  The table for translating pcre_compile() error codes into POSIX error codes
1039        was out-of-date, and there was no check on the pcre_compile() error code
1040        being within the table. This could lead to an OK return being given in
1041        error.
1043    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
1044        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
1045        in a Windows environment.
1047    3.  The pcregrep --count option prints the count for each file even when it is
1048        zero, as does GNU grep. However, pcregrep was also printing all files when
1049        --files-with-matches was added. Now, when both options are given, it prints
1050        counts only for those files that have at least one match. (GNU grep just
1051        prints the file name in this circumstance, but including the count seems
1052        more useful - otherwise, why use --count?) Also ensured that the
1053        combination -clh just lists non-zero counts, with no names.
1055    4.  The long form of the pcregrep -F option was incorrectly implemented as
1056        --fixed_strings instead of --fixed-strings. This is an incompatible change,
1057        but it seems right to fix it, and I didn't think it was worth preserving
1058        the old behaviour.
1060    5.  The command line items --regex=pattern and --regexp=pattern were not
1061        recognized by pcregrep, which required --regex pattern or --regexp pattern
1062        (with a space rather than an '='). The man page documented the '=' forms,
1063        which are compatible with GNU grep; these now work.
1065    6.  No libpcreposix.pc file was created for pkg-config; there was just
1066        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
1068    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
1069        when UCP support is not needed, by modifying the Python script that
1070        generates it from Unicode data files. This should not matter if the module
1071        is correctly used as a library, but I received one complaint about 50K of
1072        unwanted data. My guess is that the person linked everything into his
1073        program rather than using a library. Anyway, it does no harm.
1075    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
1076        was a minimum greater than 1 for a wide character in a possessive
1077        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
1078        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
1079        character. Chaos in the form of incorrect output or a compiling loop could
1080        result.
1082    9.  The restrictions on what a pattern can contain when partial matching is
1083        requested for pcre_exec() have been removed. All patterns can now be
1084        partially matched by this function. In addition, if there are at least two
1085        slots in the offset vector, the offset of the earliest inspected character
1086        for the match and the offset of the end of the subject are set in them when
1087        PCRE_ERROR_PARTIAL is returned.
1089    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
1090        synonymous with PCRE_PARTIAL, for backwards compatibility, and
1091        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
1092        and may be more useful for multi-segment matching.
1094    11. Partial matching with pcre_exec() is now more intuitive. A partial match
1095        used to be given if ever the end of the subject was reached; now it is
1096        given only if matching could not proceed because another character was
1097        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
1098        string "Z", which now yields "no match" instead of "partial match". In the
1099        case of pcre_dfa_exec(), "no match" is given if every matching path for the
1100        final character ended with (*FAIL).
1102    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
1103        if the pattern had a "must contain" character that was already found in the
1104        earlier partial match, unless partial matching was again requested. For
1105        example, with the pattern /dog.(body)?/, the "must contain" character is
1106        "g". If the first part-match was for the string "dog", restarting with
1107        "sbody" failed. This bug has been fixed.
1109    13. The string returned by pcre_dfa_exec() after a partial match has been
1110        changed so that it starts at the first inspected character rather than the
1111        first character of the match. This makes a difference only if the pattern
1112        starts with a lookbehind assertion or \b or \B (\K is not supported by
1113        pcre_dfa_exec()). It's an incompatible change, but it makes the two
1114        matching functions compatible, and I think it's the right thing to do.
1116    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
1117        so that the demonstration program is easily available in environments where
1118        PCRE has not been installed from source.
1120    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
1121        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
1122        library.
1124    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
1125        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
1126        is not the first non-POSIX option to be added. Clearly some people find
1127        these options useful.
1129    17. If a caller to the POSIX matching function regexec() passes a non-zero
1130        value for nmatch with a NULL value for pmatch, the value of
1131        nmatch is forced to zero.
1133    18. RunGrepTest did not have a test for the availability of the -u option of
1134        the diff command, as RunTest does. It now checks in the same way as
1135        RunTest, and also checks for the -b option.
1137    19. If an odd number of negated classes containing just a single character
1138        interposed, within parentheses, between a forward reference to a named
1139        subpattern and the definition of the subpattern, compilation crashed with
1140        an internal error, complaining that it could not find the referenced
1141        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
1142        [The bug was that it was starting one character too far in when skipping
1143        over the character class, thus treating the ] as data rather than
1144        terminating the class. This meant it could skip too much.]
1146    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
1147        /g option in pcretest when the pattern contains \K, which makes it possible
1148        to have an empty string match not at the start, even when the pattern is
1149        anchored. Updated pcretest and pcredemo to use this option.
1151    21. If the maximum number of capturing subpatterns in a recursion was greater
1152        than the maximum at the outer level, the higher number was returned, but
1153        with unset values at the outer level. The correct (outer level) value is
1154        now given.
1156    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1157        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1158        make it do so. The string so far is captured, making this feature
1159        compatible with Perl.
1161    23. The tests have been re-organized, adding tests 11 and 12, to make it
1162        possible to check the Perl 5.10 features against Perl 5.10.
1164    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1165        pattern matches a fixed length string. PCRE did not allow this; now it
1166        does. Neither allows recursion.
1168    25. I finally figured out how to implement a request to provide the minimum
1169        length of subject string that was needed in order to match a given pattern.
1170        (It was back references and recursion that I had previously got hung up
1171        on.) This code has now been added to pcre_study(); it finds a lower bound
1172        to the length of subject needed. It is not necessarily the greatest lower
1173        bound, but using it to avoid searching strings that are too short does give
1174        some useful speed-ups. The value is available to calling programs via
1175        pcre_fullinfo().
1177    26. While implementing 25, I discovered to my embarrassment that pcretest had
1178        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1179        study optimizations had never been tested with that matching function.
1180        Oops. What is worse, even when it was passed study data, there was a bug in
1181        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1182        were also very few tests of studied patterns with pcre_dfa_exec().
1184    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1185        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1186        on the other side of the coin, they are no longer allowed to have different
1187        names, because these cannot be distinguished in PCRE, and this has caused
1188        confusion. (This is a difference from Perl.)
1190    28. When duplicate subpattern names are present (necessarily with different
1191        numbers, as required by 27 above), and a test is made by name in a
1192        conditional pattern, either for a subpattern having been matched, or for
1193        recursion in such a pattern, all the associated numbered subpatterns are
1194        tested, and the overall condition is true if the condition is true for any
1195        one of them. This is the way Perl works, and is also more like the way
1196        testing by number works.
1199    Version 7.9 11-Apr-09
1200    ---------------------
1202    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1203        (pcretest), all targets were linked against these libraries. This included
1204        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1205        libraries. This caused unwanted dependencies to be created. This problem
1206        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1207        pcretest is linked with readline.
1209    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1210        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1211        moved outside it again, because FALSE and TRUE are already defined in AIX,
1212        but BOOL is not.
1214    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1215        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1217    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1218        hyphens) following file names and line numbers when outputting matching
1219        lines. This is not true; no spaces are inserted. I have also clarified the
1220        wording for the --colour (or --color) option.
1222    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1223        was not coloured; this is different to GNU grep, so I have changed it to be
1224        the same.
1226    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1227        each matching line was coloured. Now it goes on to look for further matches
1228        of any of the test patterns, which is the same behaviour as GNU grep.
1230    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1231        doesn't make sense to accept an empty string match in pcregrep, so I have
1232        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1233        seems to be how GNU grep behaves.
1235    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1236        start or after a newline", because the conditional assertion was not being
1237        correctly handled. The rule now is that both the assertion and what follows
1238        in the first alternative must satisfy the test.
1240    9.  If auto-callout was enabled in a pattern with a conditional group whose
1241        condition was an assertion, PCRE could crash during matching, both with
1242        pcre_exec() and pcre_dfa_exec().
1244    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1245        used for matching.
1247    11. Unicode property support in character classes was not working for
1248        characters (bytes) greater than 127 when not in UTF-8 mode.
1250    12. Added the -M command line option to pcretest.
1252    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1254    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1256    16. Added comments and documentation about mis-use of no_arg in the C++
1257        wrapper.
1259    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1260        from Martin Jerabek that uses macro names for all relevant character and
1261        string constants.
1263    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1264        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1265        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1266        these, but not everybody uses configure.
1268    19. A conditional group that had only one branch was not being correctly
1269        recognized as an item that could match an empty string. This meant that an
1270        enclosing group might also not be so recognized, causing infinite looping
1271        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1272        with the subject "ab", where knowledge that the repeated group can match
1273        nothing is needed in order to break the loop.
1275    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1276        exec(), but without supplying a callout function, matching went wrong.
1278    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1279        leak if the size of the offset vector was greater than 30. When the vector
1280        is smaller, the saved offsets during recursion go onto a local stack
1281        vector, but for larger vectors malloc() is used. It was failing to free
1282        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1283        error, in fact).
1285    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1286        heapframe that is used only when UTF-8 support is enabled. This caused no
1287        problem, but was untidy.
1289    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1290        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1291        included within another project.
1293    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1294        slightly modified by me:
1296          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1297              not building pcregrep.
1299          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1300              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1302    25. Forward references, both numeric and by name, in patterns that made use of
1303        duplicate group numbers, could behave incorrectly or give incorrect errors,
1304        because when scanning forward to find the reference group, PCRE was not
1305        taking into account the duplicate group numbers. A pattern such as
1306        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1308    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1309        the feature of a custom pointer more persuasive (as requested by a user).
1311    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1312        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1313        pre-defined.
1315    28. Added support for (*UTF8) at the start of a pattern.
1317    29. Arrange for flags added by the "release type" setting in CMake to be shown
1318        in the configuration summary.
1321    Version 7.8 05-Sep-08
1322    ---------------------
1324    1.  Replaced UCP searching code with optimized version as implemented for Ad
1325        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1326        stage table and inline lookup instead of a function, giving speed ups of 2
1327        to 5 times on some simple patterns that I tested. Permission was given to
1328        distribute the MultiStage2.py script that generates the tables (it's not in
1329        the tarball, but is in the Subversion repository).
1331    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1332        scripts.
1334    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1335        a group with a zero qualifier. The result of the study could be incorrect,
1336        or the function might crash, depending on the pattern.
1338    4.  Caseless matching was not working for non-ASCII characters in back
1339        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1340        It now works when Unicode Property Support is available.
1342    5.  In pcretest, an escape such as \x{de} in the data was always generating
1343        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1344        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1345        truncation.
1347    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1349    7.  Added two (int) casts to pcregrep when printing the difference of two
1350        pointers, in case they are 64-bit values.
1352    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1353        test 2 if it fails.
1355    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1356        and a #define of that name to empty if it is not externally set. This is to
1357        allow users of MSVC to set it if necessary.
1359    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1360        the convenience functions in the pcre_get.c source file.
1362    11. An option change at the start of a pattern that had top-level alternatives
1363        could cause overwriting and/or a crash. This command provoked a crash in
1364        some environments:
1366          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1368        This potential security problem was recorded as CVE-2008-2371.
1370    12. For a pattern where the match had to start at the beginning or immediately
1371        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1372        pcre_dfa_exec() could read past the end of the passed subject if there was
1373        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1374        pcretest so that it places the subject at the end of its malloc-ed buffer.
1376    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1377        exec() might read past the end of the data buffer in UTF-8 mode.
1379    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1380        the data contained the byte 0x85 as part of a UTF-8 character within its
1381        first line. This applied both to normal and DFA matching.
1383    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1384        /^[^d]*?$/8 failed to match "abc".
1386    16. Added a missing copyright notice to pcrecpp_internal.h.
1388    17. Make it more clear in the documentation that values returned from
1389        pcre_exec() in ovector are byte offsets, not character counts.
1391    18. Tidied a few places to stop certain compilers from issuing warnings.
1393    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1394        supplied by Stefan Weber. I made a further small update for 7.8 because
1395        there is a change of source arrangements: the pcre_searchfuncs.c module is
1396        replaced by pcre_ucd.c.
1399    Version 7.7 07-May-08
1400    ---------------------
1402    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1403        a string to a long long, pretend we don't even have a long long." This is
1404        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1406    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1407        pre-7.6 versions, which defined a global no_arg variable instead of putting
1408        it in the RE class. (See also #8 below.)
1410    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1411        Lopes.
1413    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1415        (1) The include/exclude patterns were being applied to the whole pathnames
1416            of files, instead of just to the final components.
1418        (2) If there was more than one level of directory, the subdirectories were
1419            skipped unless they satisfied the include/exclude conditions. This is
1420            inconsistent with GNU grep (and could even be seen as contrary to the
1421            pcregrep specification - which I improved to make it absolutely clear).
1422            The action now is always to scan all levels of directory, and just
1423            apply the include/exclude patterns to regular files.
1425    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1426        --exclude_dir in the tests to avoid scanning .svn directories.
1428    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1429        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1430        doesn't support NULs in patterns.
1432    7.  Added some missing "const"s to declarations of static tables in
1433        pcre_compile.c and pcre_dfa_exec.c.
1435    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1436        caused by fix #2  above. (Subsequently also a second patch to fix the
1437        first patch. And a third patch - this was a messy problem.)
1439    9.  Applied Craig's patch to remove the use of push_back().
1441    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1442        matching function regexec().
1444    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1445        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1446        references. PCRE supports relative numbers with this syntax (I don't think
1447        Oniguruma does).
1449    12. Previously, a group with a zero repeat such as (...){0} was completely
1450        omitted from the compiled regex. However, this means that if the group
1451        was called as a subroutine from elsewhere in the pattern, things went wrong
1452        (an internal error was given). Such groups are now left in the compiled
1453        pattern, with a new opcode that causes them to be skipped at execution
1454        time.
1456    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1457        to the way PCRE behaves:
1459        (a) A lone ] character is dis-allowed (Perl treats it as data).
1461        (b) A back reference to an unmatched subpattern matches an empty string
1462            (Perl fails the current match path).
1464        (c) A data ] in a character class must be notated as \] because if the
1465            first data character in a class is ], it defines an empty class. (In
1466            Perl it is not possible to have an empty class.) The empty class []
1467            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1468            The negative empty class [^] matches any one character, independently
1469            of the DOTALL setting.
1471    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1472        non-existent subpattern following a character class starting with ']' and
1473        containing () gave an internal compiling error instead of "reference to
1474        non-existent subpattern". Fortunately, when the pattern did exist, the
1475        compiled code was correct. (When scanning forwards to check for the
1476        existencd of the subpattern, it was treating the data ']' as terminating
1477        the class, so got the count wrong. When actually compiling, the reference
1478        was subsequently set up correctly.)
1480    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1481        it was being rejected as not supported by pcre_dfa_exec(), even though
1482        other assertions are supported. I have made pcre_dfa_exec() support
1483        (*FAIL).
1485    16. The implementation of 13c above involved the invention of a new opcode,
1486        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1487        cannot be changed at match time, I realized I could make a small
1488        improvement to matching performance by compiling OP_ALLANY instead of
1489        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1490        on the OP_ANY path.
1492    17. Compiling pcretest on Windows with readline support failed without the
1493        following two fixes: (1) Make the unistd.h include conditional on
1494        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1496    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1497        ncurses library to be included for pcretest when ReadLine support is
1498        requested, but also to allow for it to be overridden. This patch came from
1499        Daniel Bergström.
1501    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1502        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1503        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1504        spotting this.
1507    Version 7.6 28-Jan-08
1508    ---------------------
1510    1.  A character class containing a very large number of characters with
1511        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1512        overflow.
1514    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1515        HAVE_LONG_LONG is not defined.
1517    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1518        bring them up to date and include new features. This patch includes:
1520        - Fixed PH's badly added libz and libbz2 support.
1521        - Fixed a problem with static linking.
1522        - Added pcredemo. [But later removed - see 7 below.]
1523        - Fixed dftables problem and added an option.
1524        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1525            HAVE_LONG_LONG.
1526        - Added readline support for pcretest.
1527        - Added an listing of the option settings after cmake has run.
1529    4.  A user submitted a patch to Makefile that makes it easy to create
1530        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1531        Makefile.am that cause it to include this special target, without
1532        affecting anything else. Note that the same mingw target plus all
1533        the other distribution libraries and programs are now supported
1534        when configuring with CMake (see 6 below) instead of with
1535        Configure/Make.
1537    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1538        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1539        exported in the Windows port". It has not yet been confirmed that the patch
1540        solves the problem, but it does no harm.
1542    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1543        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1544        with CMake, and also correct the comment about stack recursion.
1546    7.  Remove the automatic building of pcredemo from the ./configure system and
1547        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1548        of a program that users should build themselves after PCRE is installed, so
1549        building it automatically is not really right. What is more, it gave
1550        trouble in some build environments.
1552    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1555    Version 7.5 10-Jan-08
1556    ---------------------
1558    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1559        values in parens when parsing an RE using the C++ wrapper."
1561    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1562        Characters greater than 255 were excluded from the class instead of being
1563        included.
1565    3.  The same bug as (2) above applied to negated POSIX classes such as
1566        [:^space:].
1568    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1569        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1570        I have changed it.
1572    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1573        first named subpattern) and a construct such as (?&a) would reference the
1574        first named subpattern whose name started with "a" (in other words, the
1575        length check was missing). Both these problems are fixed. "Subpattern name
1576        expected" is now given for (?&) (a zero-length name), and this patch also
1577        makes it give the same error for \k'' (previously it complained that that
1578        was a reference to a non-existent subpattern).
1580    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1581        this is right because (?- can be followed by option settings as well as by
1582        digits. I have, however, made the messages clearer.
1584    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1585        than the number used in the conditional) now cause a compile-time error.
1586        This is actually not compatible with Perl, which accepts such patterns, but
1587        treats the conditional as always being FALSE (as PCRE used to), but it
1588        seems to me that giving a diagnostic is better.
1590    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1591        and messages.
1593    9.  Fix two occurrences of "backslash" in comments that should have been
1594        "backspace".
1596    10. Remove two redundant lines of code that can never be obeyed (their function
1597        was moved elsewhere).
1599    11. The program that makes PCRE's Unicode character property table had a bug
1600        which caused it to generate incorrect table entries for sequences of
1601        characters that have the same character type, but are in different scripts.
1602        It amalgamated them into a single range, with the script of the first of
1603        them. In other words, some characters were in the wrong script. There were
1604        thirteen such cases, affecting characters in the following ranges:
1606          U+002b0 - U+002c1
1607          U+0060c - U+0060d
1608          U+0061e - U+00612
1609          U+0064b - U+0065e
1610          U+0074d - U+0076d
1611          U+01800 - U+01805
1612          U+01d00 - U+01d77
1613          U+01d9b - U+01dbf
1614          U+0200b - U+0200f
1615          U+030fc - U+030fe
1616          U+03260 - U+0327f
1617          U+0fb46 - U+0fbb1
1618          U+10450 - U+1049d
1620    12. The -o option (show only the matching part of a line) for pcregrep was not
1621        compatible with GNU grep in that, if there was more than one match in a
1622        line, it showed only the first of them. It now behaves in the same way as
1623        GNU grep.
1625    13. If the -o and -v options were combined for pcregrep, it printed a blank
1626        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1627        does the same. The return code can be used to tell if there were any
1628        non-matching lines.
1630    14. Added --file-offsets and --line-offsets to pcregrep.
1632    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1633        infinitely looping recursion. The bug was that positive lookaheads were not
1634        being skipped when checking for a possible empty match (negative lookaheads
1635        and both kinds of lookbehind were skipped).
1637    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1638        inclusion of <windows.h> to before rather than after the definition of
1639        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1641    17. Specifying a possessive quantifier with a specific limit for a Unicode
1642        character property caused pcre_compile() to compile bad code, which led at
1643        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1644        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1645        caused the error; without that there was no problem.
1647    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1649    19. Added --enable-pcretest-libreadline.
1651    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1652        RE::GlobalReplace(). As a result, the number of replacements returned was
1653        double what it should be. I removed one of the increments, but Craig sent a
1654        later patch that removed the other one (the right fix) and added unit tests
1655        that check the return values (which was not done before).
1657    21. Several CMake things:
1659        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1660            the names libpcre and libpcreposix, not just pcre and pcreposix.
1662        (2) The above change means that pcretest and pcregrep are now correctly
1663            linked with the newly-built libraries, not previously installed ones.
1667    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1668        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1669        UTF-8 newline character). The key issue is that the pattern starts .*;
1670        this means that the match must be either at the beginning, or after a
1671        newline. The bug was in the code for advancing after a failed match and
1672        checking that the new position followed a newline. It was not taking
1673        account of UTF-8 characters correctly.
1675    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1676        character classes. PCRE was not treating the sequence [:...:] as a
1677        character class unless the ... were all letters. Perl, however, seems to
1678        allow any characters between [: and :], though of course it rejects as
1679        unknown any "names" that contain non-letters, because all the known class
1680        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1681        for example, whereas PCRE did not - it did not recognize a POSIX character
1682        class. This seemed a bit dangerous, so the code has been changed to be
1683        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1684        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1685        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1686        Perl does, and where it didn't before.
1688    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1689        Windows environments %n is disabled by default.
1692    Version 7.4 21-Sep-07
1693    ---------------------
1695    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1696        means that a class such as [\s] counted as "explicit reference to CR or
1697        LF". That isn't really right - the whole point of the change was to try to
1698        help when there was an actual mention of one of the two characters. So now
1699        the change happens only if \r or \n (or a literal CR or LF) character is
1700        encountered.
1702    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1703        of both had grown to the point where there were only 3 bits left.
1704        Fortunately, there was spare space in the data structure, and so I have
1705        moved the internal flags into a new 16-bit field to free up more option
1706        bits.
1708    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1709        but did not set the internal JCHANGED flag - either of these is enough to
1710        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1711        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1712        start sets both bits.
1714    4.  Added options (at build time, compile time, exec time) to change \R from
1715        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1717    5.  doc/pcresyntax.html was missing from the distribution.
1719    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1720        compatibility, even though it is no longer used.
1722    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1723        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1724        windows.h file is present (where different names are used). [This was
1725        reversed later after testing - see 16 below.]
1727    8.  Changed all #include <config.h> to #include "config.h". There were also
1728        some further <pcre.h> cases that I changed to "pcre.h".
1730    9.  When pcregrep was used with the --colour option, it missed the line ending
1731        sequence off the lines that it output.
1733    10. It was pointed out to me that arrays of string pointers cause lots of
1734        relocations when a shared library is dynamically loaded. A technique of
1735        using a single long string with a table of offsets can drastically reduce
1736        these. I have refactored PCRE in four places to do this. The result is
1737        dramatic:
1739          Originally:                          290
1740          After changing UCP table:            187
1741          After changing error message table:   43
1742          After changing table of "verbs"       36
1743          After changing table of Posix names   22
1745        Thanks to the folks working on Gregex for glib for this insight.
1747    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1748        unicode-properties was also set.
1750    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1752    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1753        checked only for CRLF.
1755    14. Added casts to pcretest.c to avoid compiler warnings.
1757    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1759    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1760        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1761        entirely. This removes changes made in 7 above.
1763    17. The CMake files have been updated, and there is now more information about
1764        building with CMake in the NON-UNIX-USE document.
1767    Version 7.3 28-Aug-07
1768    ---------------------
1770     1. In the rejigging of the build system that eventually resulted in 7.1, the
1771        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1772        brackets there is not right, since it causes compilers to look for an
1773        installed pcre.h, not the version that is in the source that is being
1774        compiled (which of course may be different). I have changed it back to:
1776          #include "pcre.h"
1778        I have a vague recollection that the change was concerned with compiling in
1779        different directories, but in the new build system, that is taken care of
1780        by the VPATH setting the Makefile.
1782     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1783        when the subject happened to end in the byte 0x85 (e.g. if the last
1784        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1785        characters but of course it shouldn't be taken as a newline when it is part
1786        of another character. The bug was that, for an unlimited repeat of . in
1787        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1788        characters when looking for a newline.
1790     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1792     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1793        in debug output.
1795     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1796        long printing in the pcrecpp unittest when running under MinGW.
1798     6. ESC_K was left out of the EBCDIC table.
1800     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1801        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1802        limit also applies to "virtual nesting" when a pattern is recursive, and in
1803        this case 1000 isn't so big. I have been able to remove this limit at the
1804        expense of backing off one optimization in certain circumstances. Normally,
1805        when pcre_exec() would call its internal match() function recursively and
1806        immediately return the result unconditionally, it uses a "tail recursion"
1807        feature to save stack. However, when a subpattern that can match an empty
1808        string has an unlimited repetition quantifier, it no longer makes this
1809        optimization. That gives it a stack frame in which to save the data for
1810        checking that an empty string has been matched. Previously this was taken
1811        from the 1000-entry workspace that had been reserved. So now there is no
1812        explicit limit, but more stack is used.
1814     8. Applied Daniel's patches to solve problems with the import/export magic
1815        syntax that is required for Windows, and which was going wrong for the
1816        pcreposix and pcrecpp parts of the library. These were overlooked when this
1817        problem was solved for the main library.
1819     9. There were some crude static tests to avoid integer overflow when computing
1820        the size of patterns that contain repeated groups with explicit upper
1821        limits. As the maximum quantifier is 65535, the maximum group length was
1822        set at 30,000 so that the product of these two numbers did not overflow a
1823        32-bit integer. However, it turns out that people want to use groups that
1824        are longer than 30,000 bytes (though not repeat them that many times).
1825        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1826        made it possible to implement the integer overflow checks in a much more
1827        dynamic way, which I have now done. The artificial limitation on group
1828        length has been removed - we now have only the limit on the total length of
1829        the compiled pattern, which depends on the LINK_SIZE setting.
1831    10. Fixed a bug in the documentation for get/copy named substring when
1832        duplicate names are permitted. If none of the named substrings are set, the
1833        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1834        empty string.
1836    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1837        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1838        because the ] is interpreted as the first data character and the
1839        terminating ] is not found. PCRE has been made compatible with Perl in this
1840        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1841        cause memory overwriting.
1843    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1844        string has been matched (to stop an infinite loop). It was not recognizing
1845        a conditional subpattern that could match an empty string if that
1846        subpattern was within another subpattern. For example, it looped when
1847        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1848        condition was not nested. This bug has been fixed.
1850    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1851        past the start of the subject in the presence of bytes with the top bit
1852        set, for example "\x8aBCD".
1854    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1855        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1857    14. Optimized (?!) to (*FAIL).
1859    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1860        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1861        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1862        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1863        does: it's just the validity check that is more restrictive.
1865    16. Inserted checks for integer overflows during escape sequence (backslash)
1866        processing, and also fixed erroneous offset values for syntax errors during
1867        backslash processing.
1869    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1870        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1872    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1873        caused an overrun.
1875    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1876        something other than just ASCII characters) inside a group that had an
1877        unlimited repeat caused a loop at compile time (while checking to see
1878        whether the group could match an empty string).
1880    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1881        [\P{Any}] did so. (Error in the code for printing property names.)
1883    21. An orphan \E inside a character class could cause a crash.
1885    22. A repeated capturing bracket such as (A)? could cause a wild memory
1886        reference during compilation.
1888    23. There are several functions in pcre_compile() that scan along a compiled
1889        expression for various reasons (e.g. to see if it's fixed length for look
1890        behind). There were bugs in these functions when a repeated \p or \P was
1891        present in the pattern. These operators have additional parameters compared
1892        with \d, etc, and these were not being taken into account when moving along
1893        the compiled data. Specifically:
1895        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1896            length.
1898        (b) An item such as \pL+ within a repeated group could cause crashes or
1899            loops.
1901        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1902            "reference to non-existent subpattern" error.
1904        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1906    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1907        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1909    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1911    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1912        character were causing crashes (broken optimization).
1914    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1915        \p or \P) caused a compile-time loop.
1917    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1918        break. For example, the unstudied pattern [\r\n]A does not match the string
1919        "\r\nA" because change 7.0/46 below moves the current point on by two
1920        characters after failing to match at the start. However, the pattern \nA
1921        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1922        the same is true. There doesn't seem any very clean way out of this, but
1923        what I have chosen to do makes the common cases work: PCRE now takes note
1924        of whether there can be an explicit match for \r or \n anywhere in the
1925        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1926        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1927        pattern has explicit CR or LF references.
1929    29. Added (*CR) etc for changing newline setting at start of pattern.
1932    Version 7.2 19-Jun-07
1933  ---------------------  ---------------------
1935   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1936      which is apparently normally available under Windows.      which is apparently normally available under Windows.
1938     2. Re-jig the pcregrep tests with different newline settings in an attempt
1939        to make them independent of the local environment's newline setting.
1941     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1943     4. Some of the "internals" tests were previously cut out when the link size
1944        was not 2, because the output contained actual offsets. The recent new
1945        "Z" feature of pcretest means that these can be cut out, making the tests
1946        usable with all link sizes.
1948     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1949        stack recursion. This gives a massive performance boost under BSD, but just
1950        a small improvement under Linux. However, it saves one field in the frame
1951        in all cases.
1953     6. Added more features from the forthcoming Perl 5.10:
1955        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1956            recursion call. It refers to the nth most recently opened parentheses.
1958        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1959            to be opened parentheses.
1961        (c) Conditions that refer to capturing parentheses can be specified
1962            relatively, for example, (?(-2)... or (?(+3)...
1964        (d) \K resets the start of the current match so that everything before
1965            is not part of it.
1967        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1969        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1970            reference syntax.
1972        (g) (?| introduces a group in which the numbering of parentheses in each
1973            alternative starts with the same number.
1975        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1977     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1980     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1981        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1982        for detecting groups that can match an empty string.
1984     9. A pattern with a very large number of alternatives (more than several
1985        hundred) was running out of internal workspace during the pre-compile
1986        phase, where pcre_compile() figures out how much memory will be needed. A
1987        bit of new cunning has reduced the workspace needed for groups with
1988        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1989        workspace instead of running out of the 4096 that are available.
1991    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1993    11. Applied patch from Google to remove an optimization that didn't quite work.
1994        The report of the bug said:
1996          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1997          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1998          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
2000    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
2001        it matched the wrong number of bytes.
2004  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
2005  ---------------------  ---------------------

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