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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.21
5    ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". This
60        is now checked, and causes "too many forward references" instead.
63    Version 8.20 21-Oct-2011
64    ------------------------
66    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
67        a POSIX class. After further experiments with Perl, which convinced me that
68        Perl has bugs and confusions, a closing square bracket is no longer allowed
69        in a POSIX name. This bug also affected patterns with classes that started
70        with full stops.
72    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
73        captured substring, but while checking the failing first alternative,
74        substring 1 is temporarily captured. If the output vector supplied to
75        pcre_exec() was not big enough for this capture, the yield of the function
76        was still zero ("insufficient space for captured substrings"). This cannot
77        be totally fixed without adding another stack variable, which seems a lot
78        of expense for a edge case. However, I have improved the situation in cases
79        such as /(a)(b)x|abc/ matched against "abc", where the return code
80        indicates that fewer than the maximum number of slots in the ovector have
81        been set.
83    3.  Related to (2) above: when there are more back references in a pattern than
84        slots in the output vector, pcre_exec() uses temporary memory during
85        matching, and copies in the captures as far as possible afterwards. It was
86        using the entire output vector, but this conflicts with the specification
87        that only 2/3 is used for passing back captured substrings. Now it uses
88        only the first 2/3, for compatibility. This is, of course, another edge
89        case.
91    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
92        main code base, and can be used by building with --enable-jit. When this is
93        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
94        runtime --no-jit option is given.
96    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
97        ovector, the return from the function was zero, implying that there were
98        other matches that did not fit. The correct "exactly full" value is now
99        returned.
101    6.  If a subpattern that was called recursively or as a subroutine contained
102        (*PRUNE) or any other control that caused it to give a non-standard return,
103        invalid errors such as "Error -26 (nested recursion at the same subject
104        position)" or even infinite loops could occur.
106    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
107        computing the minimum length on reaching *ACCEPT, and so ended up with the
108        wrong value of 1 rather than 0. Further investigation indicates that
109        computing a minimum subject length in the presence of *ACCEPT is difficult
110        (think back references, subroutine calls), and so I have changed the code
111        so that no minimum is registered for a pattern that contains *ACCEPT.
113    8.  If (*THEN) was present in the first (true) branch of a conditional group,
114        it was not handled as intended. [But see 16 below.]
116    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
117        Sheri Pierce.
119    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
120        the first byte in a match must be "a".
122    11. Change 17 for 8.13 increased the recursion depth for patterns like
123        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
124        pattern contains any instances of (*THEN). If it does not, the old
125        optimizations are restored. It would be nice to do this on a per-group
126        basis, but at the moment that is not feasible.
128    12. In some environments, the output of pcretest -C is CRLF terminated. This
129        broke RunTest's code that checks for the link size. A single white space
130        character after the value is now allowed for.
132    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
133        For "fr", it uses the Windows-specific input and output files.
135    14. If (*THEN) appeared in a group that was called recursively or as a
136        subroutine, it did not work as intended. [But see next item.]
138    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
139        pattern fragments (but not containing any | characters). If A and B are
140        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
141        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
142        D. In other words, Perl considers parentheses that do not contain any |
143        characters to be part of a surrounding alternative, whereas PCRE was
144        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
145        differently. PCRE now behaves in the same way as Perl, except in the case
146        of subroutine/recursion calls such as (?1) which have in any case always
147        been different (but PCRE had them first :-).
149    16. Related to 15 above: Perl does not treat the | in a conditional group as
150        creating alternatives. Such a group is treated in the same way as an
151        ordinary group without any | characters when processing (*THEN). PCRE has
152        been changed to match Perl's behaviour.
154    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
155        RunGrepTest script failed.
157    18. Change 22 for version 13 caused atomic groups to use more stack. This is
158        inevitable for groups that contain captures, but it can lead to a lot of
159        stack use in large patterns. The old behaviour has been restored for atomic
160        groups that do not contain any capturing parentheses.
162    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
163        suppress the check for a minimum subject length at run time. (If it was
164        given to pcre_exec() or pcre_dfa_exec() it did work.)
166    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
167        fail to work when decoding hex characters in data strings in EBCDIC
168        environments.
170    21. It appears that in at least one Mac OS environment, the isxdigit() function
171        is implemented as a macro that evaluates to its argument more than once,
172        contravening the C 90 Standard (I haven't checked a later standard). There
173        was an instance in pcretest which caused it to go wrong when processing
174        \x{...} escapes in subject strings. The has been rewritten to avoid using
175        things like p++ in the argument of isxdigit().
178    Version 8.13 16-Aug-2011
179    ------------------------
181    1.  The Unicode data tables have been updated to Unicode 6.0.0.
183    2.  Two minor typos in pcre_internal.h have been fixed.
185    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
186        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
187        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
189    4.  There were a number of related bugs in the code for matching backrefences
190        caselessly in UTF-8 mode when codes for the characters concerned were
191        different numbers of bytes. For example, U+023A and U+2C65 are an upper
192        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
193        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
194        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
195        2-byte code at the end of the subject (it thought there wasn't enough data
196        left).
198    5.  Comprehensive information about what went wrong is now returned by
199        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
200        as the output vector has at least 2 elements. The offset of the start of
201        the failing character and a reason code are placed in the vector.
203    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
204        now returned is for the first byte of the failing character, instead of the
205        last byte inspected. This is an incompatible change, but I hope it is small
206        enough not to be a problem. It makes the returned offset consistent with
207        pcre_exec() and pcre_dfa_exec().
209    7.  pcretest now gives a text phrase as well as the error number when
210        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
211        failure, the offset and reason code are output.
213    8.  When \R was used with a maximizing quantifier it failed to skip backwards
214        over a \r\n pair if the subsequent match failed. Instead, it just skipped
215        back over a single character (\n). This seems wrong (because it treated the
216        two characters as a single entity when going forwards), conflicts with the
217        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
218        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
219        has been changed.
221    9.  Some internal refactoring has changed the processing so that the handling
222        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
223        time (the PCRE_DOTALL option was changed this way some time ago: version
224        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
225        which was always a bit of a fudge. It also means that there is one less
226        argument for the match() function, which reduces its stack requirements
227        slightly. This change also fixes an incompatibility with Perl: the pattern
228        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
230    10. More internal refactoring has drastically reduced the number of recursive
231        calls to match() for possessively repeated groups such as (abc)++ when
232        using pcre_exec().
234    11. While implementing 10, a number of bugs in the handling of groups were
235        discovered and fixed:
237        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
238        (a|)*(?1) gave a compile-time internal error.
239        ((a|)+)+  did not notice that the outer group could match an empty string.
240        (^a|^)+   was not marked as anchored.
241        (.*a|.*)+ was not marked as matching at start or after a newline.
243    12. Yet more internal refactoring has removed another argument from the match()
244        function. Special calls to this function are now indicated by setting a
245        value in a variable in the "match data" data block.
247    13. Be more explicit in pcre_study() instead of relying on "default" for
248        opcodes that mean there is no starting character; this means that when new
249        ones are added and accidentally left out of pcre_study(), testing should
250        pick them up.
252    14. The -s option of pcretest has been documented for ages as being an old
253        synonym of -m (show memory usage). I have changed it to mean "force study
254        for every regex", that is, assume /S for every regex. This is similar to -i
255        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
256        using it. It makes it easier to run collections of tests with and without
257        study enabled, and thereby test pcre_study() more easily. All the standard
258        tests are now run with and without -s (but some patterns can be marked as
259        "never study" - see 20 below).
261    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
262        restoration of the capturing data to the outer values was not happening
263        correctly.
265    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
266        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
267        pattern had matched an empty string, and so incorrectly returned a no
268        match.
270    17. There was optimizing code for the last branch of non-capturing parentheses,
271        and also for the obeyed branch of a conditional subexpression, which used
272        tail recursion to cut down on stack usage. Unfortunately, now that there is
273        the possibility of (*THEN) occurring in these branches, tail recursion is
274        no longer possible because the return has to be checked for (*THEN). These
275        two optimizations have therefore been removed. [But see 8.20/11 above.]
277    18. If a pattern containing \R was studied, it was assumed that \R always
278        matched two bytes, thus causing the minimum subject length to be
279        incorrectly computed because \R can also match just one byte.
281    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
282        was incorrectly computed.
284    20. If /S is present twice on a test pattern in pcretest input, it now
285        *disables* studying, thereby overriding the use of -s on the command line
286        (see 14 above). This is necessary for one or two tests to keep the output
287        identical in both cases.
289    21. When (*ACCEPT) was used in an assertion that matched an empty string and
290        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
292    22. When an atomic group that contained a capturing parenthesis was
293        successfully matched, but the branch in which it appeared failed, the
294        capturing was not being forgotten if a higher numbered group was later
295        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
296        group 1 to "a", when in fact it should be unset. This applied to multi-
297        branched capturing and non-capturing groups, repeated or not, and also to
298        positive assertions (capturing in negative assertions does not happen
299        in PCRE) and also to nested atomic groups.
301    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
302        subject after a captured substring, to make it easier to tell which of a
303        number of identical substrings has been captured.
305    24. The way atomic groups are processed by pcre_exec() has been changed so that
306        if they are repeated, backtracking one repetition now resets captured
307        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
308        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
309        "aaa". Previously, it would have been "a". As part of this code
310        refactoring, the way recursive calls are handled has also been changed.
312    25. If an assertion condition captured any substrings, they were not passed
313        back unless some other capturing happened later. For example, if
314        (?(?=(a))a) was matched against "a", no capturing was returned.
316    26. When studying a pattern that contained subroutine calls or assertions,
317        the code for finding the minimum length of a possible match was handling
318        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
319        group 1 called group 2 while simultaneously a separate group 2 called group
320        1). A stack overflow occurred in this case. I have fixed this by limiting
321        the recursion depth to 10.
323    27. Updated RunTest.bat in the distribution to the version supplied by Tom
324        Fortmann. This supports explicit test numbers on the command line, and has
325        argument validation and error reporting.
327    28. An instance of \X with an unlimited repeat could fail if at any point the
328        first character it looked at was a mark character.
330    29. Some minor code refactoring concerning Unicode properties and scripts
331        should reduce the stack requirement of match() slightly.
333    30. Added the '=' option to pcretest to check the setting of unused capturing
334        slots at the end of the pattern, which are documented as being -1, but are
335        not included in the return count.
337    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
338        compiled something random. Now it gives a compile-time error (as does
339        Perl).
341    32. A *MARK encountered during the processing of a positive assertion is now
342        recorded and passed back (compatible with Perl).
344    33. If --only-matching or --colour was set on a pcregrep call whose pattern
345        had alternative anchored branches, the search for a second match in a line
346        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
347        matched the line "0102" twice. The same bug affected patterns that started
348        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
349        twice.
351    34. Previously, PCRE did not allow quantification of assertions. However, Perl
352        does, and because of capturing effects, quantifying parenthesized
353        assertions may at times be useful. Quantifiers are now allowed for
354        parenthesized assertions.
356    35. A minor code tidy in pcre_compile() when checking options for \R usage.
358    36. \g was being checked for fancy things in a character class, when it should
359        just be a literal "g".
361    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
362        appearance of a nested POSIX class supersedes an apparent external class.
363        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
364        unescaped square brackets may also appear as part of class names. For
365        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
366        more like Perl. (But see 8.20/1 above.)
368    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
369        was because it thought it was \N{name}, which is not supported).
371    39. Add minix to OS list not supporting the -S option in pcretest.
373    40. PCRE tries to detect cases of infinite recursion at compile time, but it
374        cannot analyze patterns in sufficient detail to catch mutual recursions
375        such as ((?1))((?2)). There is now a runtime test that gives an error if a
376        subgroup is called recursively as a subpattern for a second time at the
377        same position in the subject string. In previous releases this might have
378        been caught by the recursion limit, or it might have run out of stack.
380    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
381        happen only once. PCRE was, however incorrectly giving a compile time error
382        "recursive call could loop indefinitely" because it cannot analyze the
383        pattern in sufficient detail. The compile time test no longer happens when
384        PCRE is compiling a conditional subpattern, but actual runaway loops are
385        now caught at runtime (see 40 above).
387    42. It seems that Perl allows any characters other than a closing parenthesis
388        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
389        has been changed to be the same.
391    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
392        as not to get warnings when autogen.sh is called. Also changed
393        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
395    44. To help people who use pcregrep to scan files containing exceedingly long
396        lines, the following changes have been made:
398        (a) The default value of the buffer size parameter has been increased from
399            8K to 20K. (The actual buffer used is three times this size.)
401        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
402            PCRE is built.
404        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
405            to be set at run time.
407        (d) Numerical values in pcregrep options can be followed by K or M, for
408            example --buffer-size=50K.
410        (e) If a line being scanned overflows pcregrep's buffer, an error is now
411            given and the return code is set to 2.
413    45. Add a pointer to the latest mark to the callout data block.
415    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
416        partial match of an empty string instead of no match. This was specific to
417        the use of ".".
419    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
420        complete match instead of a partial match. This bug was dependent on both
421        the PCRE_UTF8 and PCRE_DOTALL options being set.
423    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
424        starting byte set, because \b was not being ignored.
427    Version 8.12 15-Jan-2011
428    ------------------------
430    1.  Fixed some typos in the markup of the man pages, and wrote a script that
431        checks for such things as part of the documentation building process.
433    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
434        --match-limit and --recursion-limit options (added for 8.11). In
435        particular, this made one of the standard tests fail. (The integer value
436        went into the wrong half of a long int.)
438    3.  If the --colour option was given to pcregrep with -v (invert match), it
439        did strange things, either producing crazy output, or crashing. It should,
440        of course, ignore a request for colour when reporting lines that do not
441        match.
443    4.  Another pcregrep bug caused similar problems if --colour was specified with
444        -M (multiline) and the pattern match finished with a line ending.
446    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
447        matched in multiline mode, the following line was shown as part of the
448        match. This seems wrong, so I have changed it.
450    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
451        the check for further matches in the same line (so they could be coloured)
452        to overrun the end of the current line. If another match was found, it was
453        incorrectly shown (and then shown again when found in the next line).
455    7.  If pcregrep was compiled under Windows, there was a reference to the
456        function pcregrep_exit() before it was defined. I am assuming this was
457        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
458        reported by a user. I've moved the definition above the reference.
461    Version 8.11 10-Dec-2010
462    ------------------------
464    1.  (*THEN) was not working properly if there were untried alternatives prior
465        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
466        backtracked to try for "b" instead of moving to the next alternative branch
467        at the same level (in this case, to look for "c"). The Perl documentation
468        is clear that when (*THEN) is backtracked onto, it goes to the "next
469        alternative in the innermost enclosing group".
471    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
472        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
473        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
474        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
475        (*THEN).
477    3.  If \s appeared in a character class, it removed the VT character from
478        the class, even if it had been included by some previous item, for example
479        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
480        of \s, but is part of the POSIX "space" class.)
482    4.  A partial match never returns an empty string (because you can always
483        match an empty string at the end of the subject); however the checking for
484        an empty string was starting at the "start of match" point. This has been
485        changed to the "earliest inspected character" point, because the returned
486        data for a partial match starts at this character. This means that, for
487        example, /(?<=abc)def/ gives a partial match for the subject "abc"
488        (previously it gave "no match").
490    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
491        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
492        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
493        has an implication that the given string is incomplete (because a partial
494        match is preferred over a full match). For this reason, these items now
495        give a partial match in this situation. [Aside: previously, the one case
496        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
497        match rather than a full match, which was wrong by the old rules, but is
498        now correct.]
500    6.  There was a bug in the handling of #-introduced comments, recognized when
501        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
502        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
503        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
504        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
505        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
506        places in pcre_compile().
508    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
509        comments when looking ahead for named forward references to subpatterns,
510        the only newline sequence it recognized was NL. It now handles newlines
511        according to the set newline convention.
513    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
514        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
515        cater for a lack of strerror(). These oversights have been fixed.
517    9.  Added --match-limit and --recursion-limit to pcregrep.
519    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
521    11. When the -o option was used, pcregrep was setting a return code of 1, even
522        when matches were found, and --line-buffered was not being honoured.
524    12. Added an optional parentheses number to the -o and --only-matching options
525        of pcregrep.
527    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
528        can match an empty string. The code to do it in pcretest and pcredemo
529        needed fixing:
531        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
532            only one byte after an empty string match just before CRLF (this case
533            just got forgotten; "any" and "anycrlf" were OK).
535        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
536            mode when an empty string match preceded an ASCII character followed by
537            a non-ASCII character. (The code for advancing by one character rather
538            than one byte was nonsense.)
540        (c) The pcredemo.c sample program did not have any code at all to handle
541            the cases when CRLF is a valid newline sequence.
543    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
544        as a starting offset was within the subject string. There is now a new
545        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
546        negative or greater than the length of the string. In order to test this,
547        pcretest is extended to allow the setting of negative starting offsets.
549    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
550        starting offset points to the beginning of a UTF-8 character was
551        unnecessarily clumsy. I tidied it up.
553    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
554        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
556    17. Nobody had reported that the --include_dir option, which was added in
557        release 7.7 should have been called --include-dir (hyphen, not underscore)
558        for compatibility with GNU grep. I have changed it to --include-dir, but
559        left --include_dir as an undocumented synonym, and the same for
560        --exclude-dir, though that is not available in GNU grep, at least as of
561        release 2.5.4.
563    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
564        characters from a string of bytes) have been redefined so as not to use
565        loops, in order to improve performance in some environments. At the same
566        time, I abstracted some of the common code into auxiliary macros to save
567        repetition (this should not affect the compiled code).
569    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
570        compile-time error is now given if \c is not followed by an ASCII
571        character, that is, a byte less than 128. (In EBCDIC mode, the code is
572        different, and any byte value is allowed.)
574    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
575        START_OPTIMIZE option, which is now allowed at compile time - but just
576        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
577        to pcregrep and other applications that have no direct access to PCRE
578        options. The new /Y option in pcretest sets this option when calling
579        pcre_compile().
581    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
582        back references. Groups containing recursive back references were forced to
583        be atomic by that change, but in the case of named groups, the amount of
584        memory required was incorrectly computed, leading to "Failed: internal
585        error: code overflow". This has been fixed.
587    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
588        pcretest.c, to avoid build problems in some Borland environments.
591    Version 8.10 25-Jun-2010
592    ------------------------
594    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
595        THEN.
597    2.  (*ACCEPT) was not working when inside an atomic group.
599    3.  Inside a character class, \B is treated as a literal by default, but
600        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
601        causes the error). The code is unchanged, but I tidied the documentation.
603    4.  Inside a character class, PCRE always treated \R and \X as literals,
604        whereas Perl faults them if its -w option is set. I have changed PCRE so
605        that it faults them when PCRE_EXTRA is set.
607    5.  Added support for \N, which always matches any character other than
608        newline. (It is the same as "." when PCRE_DOTALL is not set.)
610    6.  When compiling pcregrep with newer versions of gcc which may have
611        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
612        declared with attribute warn_unused_result" were given. Just casting the
613        result to (void) does not stop the warnings; a more elaborate fudge is
614        needed. I've used a macro to implement this.
616    7.  Minor change to pcretest.c to avoid a compiler warning.
618    8.  Added four artifical Unicode properties to help with an option to make
619        \s etc use properties (see next item). The new properties are: Xan
620        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
622    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
623        use Unicode properties. (*UCP) at the start of a pattern can be used to set
624        this option. Modified pcretest to add /W to test this facility. Added
625        REG_UCP to make it available via the POSIX interface.
627    10. Added --line-buffered to pcregrep.
629    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
630        studied, and the match started with a letter with a code point greater than
631        127 whose first byte was different to the first byte of the other case of
632        the letter, the other case of this starting letter was not recognized
633        (#976).
635    12. If a pattern that was studied started with a repeated Unicode property
636        test, for example, \p{Nd}+, there was the theoretical possibility of
637        setting up an incorrect bitmap of starting bytes, but fortunately it could
638        not have actually happened in practice until change 8 above was made (it
639        added property types that matched character-matching opcodes).
641    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
642        possible starting bytes for non-anchored patterns.
644    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
645        \R, and also a number of cases that involve Unicode properties, both
646        explicit and implicit when PCRE_UCP is set.
648    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
649        input, it could crash or give wrong results if characters with values
650        greater than 0xc0 were present in the subject string. (Detail: it assumed
651        UTF-8 input when processing these items.)
653    16. Added a lot of (int) casts to avoid compiler warnings in systems where
654        size_t is 64-bit (#991).
656    17. Added a check for running out of memory when PCRE is compiled with
657        --disable-stack-for-recursion (#990).
659    18. If the last data line in a file for pcretest does not have a newline on
660        the end, a newline was missing in the output.
662    19. The default pcre_chartables.c file recognizes only ASCII characters (values
663        less than 128) in its various bitmaps. However, there is a facility for
664        generating tables according to the current locale when PCRE is compiled. It
665        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
666        characters, are recognized by isspace() and therefore were getting set in
667        these tables, and indeed these tables seem to approximate to ISO 8859. This
668        caused a problem in UTF-8 mode when pcre_study() was used to create a list
669        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
670        which of course cannot start UTF-8 characters. I have changed the code so
671        that only real ASCII characters (less than 128) and the correct starting
672        bytes for UTF-8 encodings are set for characters greater than 127 when in
673        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
674        altogether.)
676    20. Added the /T option to pcretest so as to be able to run tests with non-
677        standard character tables, thus making it possible to include the tests
678        used for 19 above in the standard set of tests.
680    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
681        reference to a subpattern the other side of a comment that contains an
682        opening parenthesis caused either an internal compiling error, or a
683        reference to the wrong subpattern.
686    Version 8.02 19-Mar-2010
687    ------------------------
689    1.  The Unicode data tables have been updated to Unicode 5.2.0.
691    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
692        configured.
694    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
695        original author of that file, following a query about its status.
697    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
698        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
700    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
701        quantifier applied to a forward-referencing subroutine call, could compile
702        incorrect code or give the error "internal error: previously-checked
703        referenced subpattern not found".
705    6.  Both MS Visual Studio and Symbian OS have problems with initializing
706        variables to point to external functions. For these systems, therefore,
707        pcre_malloc etc. are now initialized to local functions that call the
708        relevant global functions.
710    7.  There were two entries missing in the vectors called coptable and poptable
711        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
712        I've fixed the data, and added a kludgy way of testing at compile time that
713        the lengths are correct (equal to the number of opcodes).
715    8.  Following on from 7, I added a similar kludge to check the length of the
716        eint vector in pcreposix.c.
718    9.  Error texts for pcre_compile() are held as one long string to avoid too
719        much relocation at load time. To find a text, the string is searched,
720        counting zeros. There was no check for running off the end of the string,
721        which could happen if a new error number was added without updating the
722        string.
724    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
726    11. \K was not working if it appeared in an atomic group or in a group that
727        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
728        \K is "not well defined" if used in an assertion. PCRE now accepts it if
729        the assertion is positive, but not if it is negative.
731    12. Change 11 fortuitously reduced the size of the stack frame used in the
732        "match()" function of pcre_exec.c by one pointer. Forthcoming
733        implementation of support for (*MARK) will need an extra pointer on the
734        stack; I have reserved it now, so that the stack frame size does not
735        decrease.
737    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
738        item in branch that calls a recursion is a subroutine call - as in the
739        second branch in the above example - was incorrectly given the compile-
740        time error "recursive call could loop indefinitely" because pcre_compile()
741        was not correctly checking the subroutine for matching a non-empty string.
743    14. The checks for overrunning compiling workspace could trigger after an
744        overrun had occurred. This is a "should never occur" error, but it can be
745        triggered by pathological patterns such as hundreds of nested parentheses.
746        The checks now trigger 100 bytes before the end of the workspace.
748    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
751    Version 8.01 19-Jan-2010
752    ------------------------
754    1.  If a pattern contained a conditional subpattern with only one branch (in
755        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
756        computed the wrong minimum data length (which is of course zero for such
757        subpatterns). This could cause incorrect "no match" results.
759    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
760        the pattern is reset in the first branch, pcre_compile() failed with
761        "internal error: code overflow at offset...". This happened only when
762        the reset was to the original external option setting. (An optimization
763        abstracts leading options settings into an external setting, which was the
764        cause of this.)
766    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
767        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
768        assertion pattern did not match (meaning that the assertion was true), it
769        was incorrectly treated as false if the SKIP had been reached during the
770        matching. This also applied to assertions used as conditions.
772    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
773        assertion subpattern, including such a pattern used as a condition,
774        unpredictable results occurred, instead of the error return
777    5.  The C++ GlobalReplace function was not working like Perl for the special
778        situation when an empty string is matched. It now does the fancy magic
779        stuff that is necessary.
781    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
782        removed. (These were left over from very, very early versions of PCRE.)
784    7.  Some cosmetic changes to the code to make life easier when compiling it
785        as part of something else:
787        (a) Change DEBUG to PCRE_DEBUG.
789        (b) In pcre_compile(), rename the member of the "branch_chain" structure
790            called "current" as "current_branch", to prevent a collision with the
791            Linux macro when compiled as a kernel module.
793        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
794            prevent a collision with the Linux macro when compiled as a kernel
795            module.
797    8.  In pcre_compile() there are some checks for integer overflows that used to
798        cast potentially large values to (double). This has been changed to that
799        when building, a check for int64_t is made, and if it is found, it is used
800        instead, thus avoiding the use of floating point arithmetic. (There is no
801        other use of FP in PCRE.) If int64_t is not found, the fallback is to
802        double.
804    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
805        2005 (difference between two addresses compared to an unsigned value).
807    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
808        custom one, because of the following reported problem in Windows:
810          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
811              under Win32.
812          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
813              therefore missing the function definition.
814          - The compiler thus generates a "C" signature for the test function.
815          - The linker fails to find the "C" function.
816          - PCRE fails to configure if asked to do so against libbz2.
818    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
819        messages were output:
821          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
822          rerunning libtoolize, to keep the correct libtool macros in-tree.
823          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
825        I have done both of these things.
827    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
828        most of the time, it *can* run out if it is given a pattern that contains a
829        runaway infinite recursion. I updated the discussion in the pcrestack man
830        page.
832    13. Now that we have gone to the x.xx style of version numbers, the minor
833        version may start with zero. Using 08 or 09 is a bad idea because users
834        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
835        interpreted as invalid octal numbers. I've updated the previous comment in
836        configure.ac, and also added a check that gives an error if 08 or 09 are
837        used.
839    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
840        causing partial matching to fail when the end of the subject matched \W
841        in a UTF-8 pattern where \W was quantified with a minimum of 3.
843    15. There were some discrepancies between the declarations in pcre_internal.h
844        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
845        their definitions. The declarations used "const uschar *" and the
846        definitions used USPTR. Even though USPTR is normally defined as "const
847        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
848        reported that: "This difference in casting confuses some C++ compilers, for
849        example, SunCC recognizes above declarations as different functions and
850        generates broken code for hbpcre." I have changed the declarations to use
851        USPTR.
853    16. GNU libtool is named differently on some systems. The autogen.sh script now
854        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
855        (FreeBSD).
857    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
858        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
859        comment: "Figure out how to create a longlong from a string: strtoll and
860        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
861        instance, but it only takes 2 args instead of 3!"
863    18. A subtle bug concerned with back references has been fixed by a change of
864        specification, with a corresponding code fix. A pattern such as
865        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
866        refers, was giving matches when it shouldn't. For example, xa=xaaa would
867        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
868        same bug. Such groups have to be quantified to be useful, or contained
869        inside another quantified group. (If there's no repetition, the reference
870        can never match.) The problem arises because, having left the group and
871        moved on to the rest of the pattern, a later failure that backtracks into
872        the group uses the captured value from the final iteration of the group
873        rather than the correct earlier one. I have fixed this in PCRE by forcing
874        any group that contains a reference to itself to be an atomic group; that
875        is, there cannot be any backtracking into it once it has completed. This is
876        similar to recursive and subroutine calls.
879    Version 8.00 19-Oct-09
880    ----------------------
882    1.  The table for translating pcre_compile() error codes into POSIX error codes
883        was out-of-date, and there was no check on the pcre_compile() error code
884        being within the table. This could lead to an OK return being given in
885        error.
887    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
888        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
889        in a Windows environment.
891    3.  The pcregrep --count option prints the count for each file even when it is
892        zero, as does GNU grep. However, pcregrep was also printing all files when
893        --files-with-matches was added. Now, when both options are given, it prints
894        counts only for those files that have at least one match. (GNU grep just
895        prints the file name in this circumstance, but including the count seems
896        more useful - otherwise, why use --count?) Also ensured that the
897        combination -clh just lists non-zero counts, with no names.
899    4.  The long form of the pcregrep -F option was incorrectly implemented as
900        --fixed_strings instead of --fixed-strings. This is an incompatible change,
901        but it seems right to fix it, and I didn't think it was worth preserving
902        the old behaviour.
904    5.  The command line items --regex=pattern and --regexp=pattern were not
905        recognized by pcregrep, which required --regex pattern or --regexp pattern
906        (with a space rather than an '='). The man page documented the '=' forms,
907        which are compatible with GNU grep; these now work.
909    6.  No libpcreposix.pc file was created for pkg-config; there was just
910        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
912    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
913        when UCP support is not needed, by modifying the Python script that
914        generates it from Unicode data files. This should not matter if the module
915        is correctly used as a library, but I received one complaint about 50K of
916        unwanted data. My guess is that the person linked everything into his
917        program rather than using a library. Anyway, it does no harm.
919    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
920        was a minimum greater than 1 for a wide character in a possessive
921        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
922        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
923        character. Chaos in the form of incorrect output or a compiling loop could
924        result.
926    9.  The restrictions on what a pattern can contain when partial matching is
927        requested for pcre_exec() have been removed. All patterns can now be
928        partially matched by this function. In addition, if there are at least two
929        slots in the offset vector, the offset of the earliest inspected character
930        for the match and the offset of the end of the subject are set in them when
931        PCRE_ERROR_PARTIAL is returned.
933    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
934        synonymous with PCRE_PARTIAL, for backwards compatibility, and
935        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
936        and may be more useful for multi-segment matching.
938    11. Partial matching with pcre_exec() is now more intuitive. A partial match
939        used to be given if ever the end of the subject was reached; now it is
940        given only if matching could not proceed because another character was
941        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
942        string "Z", which now yields "no match" instead of "partial match". In the
943        case of pcre_dfa_exec(), "no match" is given if every matching path for the
944        final character ended with (*FAIL).
946    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
947        if the pattern had a "must contain" character that was already found in the
948        earlier partial match, unless partial matching was again requested. For
949        example, with the pattern /dog.(body)?/, the "must contain" character is
950        "g". If the first part-match was for the string "dog", restarting with
951        "sbody" failed. This bug has been fixed.
953    13. The string returned by pcre_dfa_exec() after a partial match has been
954        changed so that it starts at the first inspected character rather than the
955        first character of the match. This makes a difference only if the pattern
956        starts with a lookbehind assertion or \b or \B (\K is not supported by
957        pcre_dfa_exec()). It's an incompatible change, but it makes the two
958        matching functions compatible, and I think it's the right thing to do.
960    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
961        so that the demonstration program is easily available in environments where
962        PCRE has not been installed from source.
964    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
965        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
966        library.
968    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
969        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
970        is not the first non-POSIX option to be added. Clearly some people find
971        these options useful.
973    17. If a caller to the POSIX matching function regexec() passes a non-zero
974        value for nmatch with a NULL value for pmatch, the value of
975        nmatch is forced to zero.
977    18. RunGrepTest did not have a test for the availability of the -u option of
978        the diff command, as RunTest does. It now checks in the same way as
979        RunTest, and also checks for the -b option.
981    19. If an odd number of negated classes containing just a single character
982        interposed, within parentheses, between a forward reference to a named
983        subpattern and the definition of the subpattern, compilation crashed with
984        an internal error, complaining that it could not find the referenced
985        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
986        [The bug was that it was starting one character too far in when skipping
987        over the character class, thus treating the ] as data rather than
988        terminating the class. This meant it could skip too much.]
990    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
991        /g option in pcretest when the pattern contains \K, which makes it possible
992        to have an empty string match not at the start, even when the pattern is
993        anchored. Updated pcretest and pcredemo to use this option.
995    21. If the maximum number of capturing subpatterns in a recursion was greater
996        than the maximum at the outer level, the higher number was returned, but
997        with unset values at the outer level. The correct (outer level) value is
998        now given.
1000    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
1001        PCRE did not set those parentheses (unlike Perl). I have now found a way to
1002        make it do so. The string so far is captured, making this feature
1003        compatible with Perl.
1005    23. The tests have been re-organized, adding tests 11 and 12, to make it
1006        possible to check the Perl 5.10 features against Perl 5.10.
1008    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
1009        pattern matches a fixed length string. PCRE did not allow this; now it
1010        does. Neither allows recursion.
1012    25. I finally figured out how to implement a request to provide the minimum
1013        length of subject string that was needed in order to match a given pattern.
1014        (It was back references and recursion that I had previously got hung up
1015        on.) This code has now been added to pcre_study(); it finds a lower bound
1016        to the length of subject needed. It is not necessarily the greatest lower
1017        bound, but using it to avoid searching strings that are too short does give
1018        some useful speed-ups. The value is available to calling programs via
1019        pcre_fullinfo().
1021    26. While implementing 25, I discovered to my embarrassment that pcretest had
1022        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
1023        study optimizations had never been tested with that matching function.
1024        Oops. What is worse, even when it was passed study data, there was a bug in
1025        pcre_dfa_exec() that meant it never actually used it. Double oops. There
1026        were also very few tests of studied patterns with pcre_dfa_exec().
1028    27. If (?| is used to create subpatterns with duplicate numbers, they are now
1029        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
1030        on the other side of the coin, they are no longer allowed to have different
1031        names, because these cannot be distinguished in PCRE, and this has caused
1032        confusion. (This is a difference from Perl.)
1034    28. When duplicate subpattern names are present (necessarily with different
1035        numbers, as required by 27 above), and a test is made by name in a
1036        conditional pattern, either for a subpattern having been matched, or for
1037        recursion in such a pattern, all the associated numbered subpatterns are
1038        tested, and the overall condition is true if the condition is true for any
1039        one of them. This is the way Perl works, and is also more like the way
1040        testing by number works.
1043    Version 7.9 11-Apr-09
1044    ---------------------
1046    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
1047        (pcretest), all targets were linked against these libraries. This included
1048        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
1049        libraries. This caused unwanted dependencies to be created. This problem
1050        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
1051        pcretest is linked with readline.
1053    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
1054        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
1055        moved outside it again, because FALSE and TRUE are already defined in AIX,
1056        but BOOL is not.
1058    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
1059        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
1061    4.  The pcregrep documentation said spaces were inserted as well as colons (or
1062        hyphens) following file names and line numbers when outputting matching
1063        lines. This is not true; no spaces are inserted. I have also clarified the
1064        wording for the --colour (or --color) option.
1066    5.  In pcregrep, when --colour was used with -o, the list of matching strings
1067        was not coloured; this is different to GNU grep, so I have changed it to be
1068        the same.
1070    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
1071        each matching line was coloured. Now it goes on to look for further matches
1072        of any of the test patterns, which is the same behaviour as GNU grep.
1074    7.  A pattern that could match an empty string could cause pcregrep to loop; it
1075        doesn't make sense to accept an empty string match in pcregrep, so I have
1076        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
1077        seems to be how GNU grep behaves.
1079    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
1080        start or after a newline", because the conditional assertion was not being
1081        correctly handled. The rule now is that both the assertion and what follows
1082        in the first alternative must satisfy the test.
1084    9.  If auto-callout was enabled in a pattern with a conditional group whose
1085        condition was an assertion, PCRE could crash during matching, both with
1086        pcre_exec() and pcre_dfa_exec().
1088    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
1089        used for matching.
1091    11. Unicode property support in character classes was not working for
1092        characters (bytes) greater than 127 when not in UTF-8 mode.
1094    12. Added the -M command line option to pcretest.
1096    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
1098    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
1100    16. Added comments and documentation about mis-use of no_arg in the C++
1101        wrapper.
1103    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
1104        from Martin Jerabek that uses macro names for all relevant character and
1105        string constants.
1107    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
1108        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
1109        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
1110        these, but not everybody uses configure.
1112    19. A conditional group that had only one branch was not being correctly
1113        recognized as an item that could match an empty string. This meant that an
1114        enclosing group might also not be so recognized, causing infinite looping
1115        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
1116        with the subject "ab", where knowledge that the repeated group can match
1117        nothing is needed in order to break the loop.
1119    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
1120        exec(), but without supplying a callout function, matching went wrong.
1122    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
1123        leak if the size of the offset vector was greater than 30. When the vector
1124        is smaller, the saved offsets during recursion go onto a local stack
1125        vector, but for larger vectors malloc() is used. It was failing to free
1126        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
1127        error, in fact).
1129    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
1130        heapframe that is used only when UTF-8 support is enabled. This caused no
1131        problem, but was untidy.
1133    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
1134        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
1135        included within another project.
1137    24. Steven Van Ingelgem's patches to add more options to the CMake support,
1138        slightly modified by me:
1140          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
1141              not building pcregrep.
1143          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
1144              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
1146    25. Forward references, both numeric and by name, in patterns that made use of
1147        duplicate group numbers, could behave incorrectly or give incorrect errors,
1148        because when scanning forward to find the reference group, PCRE was not
1149        taking into account the duplicate group numbers. A pattern such as
1150        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
1152    26. Changed a few more instances of "const unsigned char *" to USPTR, making
1153        the feature of a custom pointer more persuasive (as requested by a user).
1155    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
1156        pcretest.c, inside #ifndefs, because it seems they are sometimes already
1157        pre-defined.
1159    28. Added support for (*UTF8) at the start of a pattern.
1161    29. Arrange for flags added by the "release type" setting in CMake to be shown
1162        in the configuration summary.
1165    Version 7.8 05-Sep-08
1166    ---------------------
1168    1.  Replaced UCP searching code with optimized version as implemented for Ad
1169        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
1170        stage table and inline lookup instead of a function, giving speed ups of 2
1171        to 5 times on some simple patterns that I tested. Permission was given to
1172        distribute the MultiStage2.py script that generates the tables (it's not in
1173        the tarball, but is in the Subversion repository).
1175    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
1176        scripts.
1178    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
1179        a group with a zero qualifier. The result of the study could be incorrect,
1180        or the function might crash, depending on the pattern.
1182    4.  Caseless matching was not working for non-ASCII characters in back
1183        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
1184        It now works when Unicode Property Support is available.
1186    5.  In pcretest, an escape such as \x{de} in the data was always generating
1187        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
1188        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
1189        truncation.
1191    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
1193    7.  Added two (int) casts to pcregrep when printing the difference of two
1194        pointers, in case they are 64-bit values.
1196    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
1197        test 2 if it fails.
1199    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
1200        and a #define of that name to empty if it is not externally set. This is to
1201        allow users of MSVC to set it if necessary.
1203    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
1204        the convenience functions in the pcre_get.c source file.
1206    11. An option change at the start of a pattern that had top-level alternatives
1207        could cause overwriting and/or a crash. This command provoked a crash in
1208        some environments:
1210          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
1212        This potential security problem was recorded as CVE-2008-2371.
1214    12. For a pattern where the match had to start at the beginning or immediately
1215        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
1216        pcre_dfa_exec() could read past the end of the passed subject if there was
1217        no match. To help with detecting such bugs (e.g. with valgrind), I modified
1218        pcretest so that it places the subject at the end of its malloc-ed buffer.
1220    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
1221        exec() might read past the end of the data buffer in UTF-8 mode.
1223    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
1224        the data contained the byte 0x85 as part of a UTF-8 character within its
1225        first line. This applied both to normal and DFA matching.
1227    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
1228        /^[^d]*?$/8 failed to match "abc".
1230    16. Added a missing copyright notice to pcrecpp_internal.h.
1232    17. Make it more clear in the documentation that values returned from
1233        pcre_exec() in ovector are byte offsets, not character counts.
1235    18. Tidied a few places to stop certain compilers from issuing warnings.
1237    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
1238        supplied by Stefan Weber. I made a further small update for 7.8 because
1239        there is a change of source arrangements: the pcre_searchfuncs.c module is
1240        replaced by pcre_ucd.c.
1243    Version 7.7 07-May-08
1244    ---------------------
1246    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
1247        a string to a long long, pretend we don't even have a long long." This is
1248        done by checking for the strtoq, strtoll, and _strtoi64 functions.
1250    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
1251        pre-7.6 versions, which defined a global no_arg variable instead of putting
1252        it in the RE class. (See also #8 below.)
1254    3.  Remove a line of dead code, identified by coverity and reported by Nuno
1255        Lopes.
1257    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
1259        (1) The include/exclude patterns were being applied to the whole pathnames
1260            of files, instead of just to the final components.
1262        (2) If there was more than one level of directory, the subdirectories were
1263            skipped unless they satisfied the include/exclude conditions. This is
1264            inconsistent with GNU grep (and could even be seen as contrary to the
1265            pcregrep specification - which I improved to make it absolutely clear).
1266            The action now is always to scan all levels of directory, and just
1267            apply the include/exclude patterns to regular files.
1269    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
1270        --exclude_dir in the tests to avoid scanning .svn directories.
1272    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
1273        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
1274        doesn't support NULs in patterns.
1276    7.  Added some missing "const"s to declarations of static tables in
1277        pcre_compile.c and pcre_dfa_exec.c.
1279    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
1280        caused by fix #2  above. (Subsequently also a second patch to fix the
1281        first patch. And a third patch - this was a messy problem.)
1283    9.  Applied Craig's patch to remove the use of push_back().
1285    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1286        matching function regexec().
1288    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1289        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1290        references. PCRE supports relative numbers with this syntax (I don't think
1291        Oniguruma does).
1293    12. Previously, a group with a zero repeat such as (...){0} was completely
1294        omitted from the compiled regex. However, this means that if the group
1295        was called as a subroutine from elsewhere in the pattern, things went wrong
1296        (an internal error was given). Such groups are now left in the compiled
1297        pattern, with a new opcode that causes them to be skipped at execution
1298        time.
1300    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1301        to the way PCRE behaves:
1303        (a) A lone ] character is dis-allowed (Perl treats it as data).
1305        (b) A back reference to an unmatched subpattern matches an empty string
1306            (Perl fails the current match path).
1308        (c) A data ] in a character class must be notated as \] because if the
1309            first data character in a class is ], it defines an empty class. (In
1310            Perl it is not possible to have an empty class.) The empty class []
1311            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1312            The negative empty class [^] matches any one character, independently
1313            of the DOTALL setting.
1315    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1316        non-existent subpattern following a character class starting with ']' and
1317        containing () gave an internal compiling error instead of "reference to
1318        non-existent subpattern". Fortunately, when the pattern did exist, the
1319        compiled code was correct. (When scanning forwards to check for the
1320        existencd of the subpattern, it was treating the data ']' as terminating
1321        the class, so got the count wrong. When actually compiling, the reference
1322        was subsequently set up correctly.)
1324    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1325        it was being rejected as not supported by pcre_dfa_exec(), even though
1326        other assertions are supported. I have made pcre_dfa_exec() support
1327        (*FAIL).
1329    16. The implementation of 13c above involved the invention of a new opcode,
1330        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1331        cannot be changed at match time, I realized I could make a small
1332        improvement to matching performance by compiling OP_ALLANY instead of
1333        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1334        on the OP_ANY path.
1336    17. Compiling pcretest on Windows with readline support failed without the
1337        following two fixes: (1) Make the unistd.h include conditional on
1338        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1340    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1341        ncurses library to be included for pcretest when ReadLine support is
1342        requested, but also to allow for it to be overridden. This patch came from
1343        Daniel Bergström.
1345    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1346        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1347        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1348        spotting this.
1351    Version 7.6 28-Jan-08
1352    ---------------------
1354    1.  A character class containing a very large number of characters with
1355        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1356        overflow.
1358    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1359        HAVE_LONG_LONG is not defined.
1361    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1362        bring them up to date and include new features. This patch includes:
1364        - Fixed PH's badly added libz and libbz2 support.
1365        - Fixed a problem with static linking.
1366        - Added pcredemo. [But later removed - see 7 below.]
1367        - Fixed dftables problem and added an option.
1368        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1369            HAVE_LONG_LONG.
1370        - Added readline support for pcretest.
1371        - Added an listing of the option settings after cmake has run.
1373    4.  A user submitted a patch to Makefile that makes it easy to create
1374        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1375        Makefile.am that cause it to include this special target, without
1376        affecting anything else. Note that the same mingw target plus all
1377        the other distribution libraries and programs are now supported
1378        when configuring with CMake (see 6 below) instead of with
1379        Configure/Make.
1381    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1382        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1383        exported in the Windows port". It has not yet been confirmed that the patch
1384        solves the problem, but it does no harm.
1386    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1387        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1388        with CMake, and also correct the comment about stack recursion.
1390    7.  Remove the automatic building of pcredemo from the ./configure system and
1391        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1392        of a program that users should build themselves after PCRE is installed, so
1393        building it automatically is not really right. What is more, it gave
1394        trouble in some build environments.
1396    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1399    Version 7.5 10-Jan-08
1400    ---------------------
1402    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1403        values in parens when parsing an RE using the C++ wrapper."
1405    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1406        Characters greater than 255 were excluded from the class instead of being
1407        included.
1409    3.  The same bug as (2) above applied to negated POSIX classes such as
1410        [:^space:].
1412    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1413        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1414        I have changed it.
1416    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1417        first named subpattern) and a construct such as (?&a) would reference the
1418        first named subpattern whose name started with "a" (in other words, the
1419        length check was missing). Both these problems are fixed. "Subpattern name
1420        expected" is now given for (?&) (a zero-length name), and this patch also
1421        makes it give the same error for \k'' (previously it complained that that
1422        was a reference to a non-existent subpattern).
1424    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1425        this is right because (?- can be followed by option settings as well as by
1426        digits. I have, however, made the messages clearer.
1428    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1429        than the number used in the conditional) now cause a compile-time error.
1430        This is actually not compatible with Perl, which accepts such patterns, but
1431        treats the conditional as always being FALSE (as PCRE used to), but it
1432        seems to me that giving a diagnostic is better.
1434    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1435        and messages.
1437    9.  Fix two occurrences of "backslash" in comments that should have been
1438        "backspace".
1440    10. Remove two redundant lines of code that can never be obeyed (their function
1441        was moved elsewhere).
1443    11. The program that makes PCRE's Unicode character property table had a bug
1444        which caused it to generate incorrect table entries for sequences of
1445        characters that have the same character type, but are in different scripts.
1446        It amalgamated them into a single range, with the script of the first of
1447        them. In other words, some characters were in the wrong script. There were
1448        thirteen such cases, affecting characters in the following ranges:
1450          U+002b0 - U+002c1
1451          U+0060c - U+0060d
1452          U+0061e - U+00612
1453          U+0064b - U+0065e
1454          U+0074d - U+0076d
1455          U+01800 - U+01805
1456          U+01d00 - U+01d77
1457          U+01d9b - U+01dbf
1458          U+0200b - U+0200f
1459          U+030fc - U+030fe
1460          U+03260 - U+0327f
1461          U+0fb46 - U+0fbb1
1462          U+10450 - U+1049d
1464    12. The -o option (show only the matching part of a line) for pcregrep was not
1465        compatible with GNU grep in that, if there was more than one match in a
1466        line, it showed only the first of them. It now behaves in the same way as
1467        GNU grep.
1469    13. If the -o and -v options were combined for pcregrep, it printed a blank
1470        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1471        does the same. The return code can be used to tell if there were any
1472        non-matching lines.
1474    14. Added --file-offsets and --line-offsets to pcregrep.
1476    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1477        infinitely looping recursion. The bug was that positive lookaheads were not
1478        being skipped when checking for a possible empty match (negative lookaheads
1479        and both kinds of lookbehind were skipped).
1481    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1482        inclusion of <windows.h> to before rather than after the definition of
1483        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1485    17. Specifying a possessive quantifier with a specific limit for a Unicode
1486        character property caused pcre_compile() to compile bad code, which led at
1487        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1488        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1489        caused the error; without that there was no problem.
1491    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1493    19. Added --enable-pcretest-libreadline.
1495    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1496        RE::GlobalReplace(). As a result, the number of replacements returned was
1497        double what it should be. I removed one of the increments, but Craig sent a
1498        later patch that removed the other one (the right fix) and added unit tests
1499        that check the return values (which was not done before).
1501    21. Several CMake things:
1503        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1504            the names libpcre and libpcreposix, not just pcre and pcreposix.
1506        (2) The above change means that pcretest and pcregrep are now correctly
1507            linked with the newly-built libraries, not previously installed ones.
1511    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1512        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1513        UTF-8 newline character). The key issue is that the pattern starts .*;
1514        this means that the match must be either at the beginning, or after a
1515        newline. The bug was in the code for advancing after a failed match and
1516        checking that the new position followed a newline. It was not taking
1517        account of UTF-8 characters correctly.
1519    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1520        character classes. PCRE was not treating the sequence [:...:] as a
1521        character class unless the ... were all letters. Perl, however, seems to
1522        allow any characters between [: and :], though of course it rejects as
1523        unknown any "names" that contain non-letters, because all the known class
1524        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1525        for example, whereas PCRE did not - it did not recognize a POSIX character
1526        class. This seemed a bit dangerous, so the code has been changed to be
1527        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1528        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1529        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1530        Perl does, and where it didn't before.
1532    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1533        Windows environments %n is disabled by default.
1536    Version 7.4 21-Sep-07
1537    ---------------------
1539    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1540        means that a class such as [\s] counted as "explicit reference to CR or
1541        LF". That isn't really right - the whole point of the change was to try to
1542        help when there was an actual mention of one of the two characters. So now
1543        the change happens only if \r or \n (or a literal CR or LF) character is
1544        encountered.
1546    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1547        of both had grown to the point where there were only 3 bits left.
1548        Fortunately, there was spare space in the data structure, and so I have
1549        moved the internal flags into a new 16-bit field to free up more option
1550        bits.
1552    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1553        but did not set the internal JCHANGED flag - either of these is enough to
1554        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1555        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1556        start sets both bits.
1558    4.  Added options (at build time, compile time, exec time) to change \R from
1559        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1561    5.  doc/pcresyntax.html was missing from the distribution.
1563    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1564        compatibility, even though it is no longer used.
1566    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1567        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1568        windows.h file is present (where different names are used). [This was
1569        reversed later after testing - see 16 below.]
1571    8.  Changed all #include <config.h> to #include "config.h". There were also
1572        some further <pcre.h> cases that I changed to "pcre.h".
1574    9.  When pcregrep was used with the --colour option, it missed the line ending
1575        sequence off the lines that it output.
1577    10. It was pointed out to me that arrays of string pointers cause lots of
1578        relocations when a shared library is dynamically loaded. A technique of
1579        using a single long string with a table of offsets can drastically reduce
1580        these. I have refactored PCRE in four places to do this. The result is
1581        dramatic:
1583          Originally:                          290
1584          After changing UCP table:            187
1585          After changing error message table:   43
1586          After changing table of "verbs"       36
1587          After changing table of Posix names   22
1589        Thanks to the folks working on Gregex for glib for this insight.
1591    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1592        unicode-properties was also set.
1594    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1596    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1597        checked only for CRLF.
1599    14. Added casts to pcretest.c to avoid compiler warnings.
1601    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1603    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1604        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1605        entirely. This removes changes made in 7 above.
1607    17. The CMake files have been updated, and there is now more information about
1608        building with CMake in the NON-UNIX-USE document.
1611    Version 7.3 28-Aug-07
1612    ---------------------
1614     1. In the rejigging of the build system that eventually resulted in 7.1, the
1615        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1616        brackets there is not right, since it causes compilers to look for an
1617        installed pcre.h, not the version that is in the source that is being
1618        compiled (which of course may be different). I have changed it back to:
1620          #include "pcre.h"
1622        I have a vague recollection that the change was concerned with compiling in
1623        different directories, but in the new build system, that is taken care of
1624        by the VPATH setting the Makefile.
1626     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1627        when the subject happened to end in the byte 0x85 (e.g. if the last
1628        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1629        characters but of course it shouldn't be taken as a newline when it is part
1630        of another character. The bug was that, for an unlimited repeat of . in
1631        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1632        characters when looking for a newline.
1634     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1636     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1637        in debug output.
1639     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1640        long printing in the pcrecpp unittest when running under MinGW.
1642     6. ESC_K was left out of the EBCDIC table.
1644     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1645        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1646        limit also applies to "virtual nesting" when a pattern is recursive, and in
1647        this case 1000 isn't so big. I have been able to remove this limit at the
1648        expense of backing off one optimization in certain circumstances. Normally,
1649        when pcre_exec() would call its internal match() function recursively and
1650        immediately return the result unconditionally, it uses a "tail recursion"
1651        feature to save stack. However, when a subpattern that can match an empty
1652        string has an unlimited repetition quantifier, it no longer makes this
1653        optimization. That gives it a stack frame in which to save the data for
1654        checking that an empty string has been matched. Previously this was taken
1655        from the 1000-entry workspace that had been reserved. So now there is no
1656        explicit limit, but more stack is used.
1658     8. Applied Daniel's patches to solve problems with the import/export magic
1659        syntax that is required for Windows, and which was going wrong for the
1660        pcreposix and pcrecpp parts of the library. These were overlooked when this
1661        problem was solved for the main library.
1663     9. There were some crude static tests to avoid integer overflow when computing
1664        the size of patterns that contain repeated groups with explicit upper
1665        limits. As the maximum quantifier is 65535, the maximum group length was
1666        set at 30,000 so that the product of these two numbers did not overflow a
1667        32-bit integer. However, it turns out that people want to use groups that
1668        are longer than 30,000 bytes (though not repeat them that many times).
1669        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1670        made it possible to implement the integer overflow checks in a much more
1671        dynamic way, which I have now done. The artificial limitation on group
1672        length has been removed - we now have only the limit on the total length of
1673        the compiled pattern, which depends on the LINK_SIZE setting.
1675    10. Fixed a bug in the documentation for get/copy named substring when
1676        duplicate names are permitted. If none of the named substrings are set, the
1677        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1678        empty string.
1680    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1681        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1682        because the ] is interpreted as the first data character and the
1683        terminating ] is not found. PCRE has been made compatible with Perl in this
1684        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1685        cause memory overwriting.
1687    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1688        string has been matched (to stop an infinite loop). It was not recognizing
1689        a conditional subpattern that could match an empty string if that
1690        subpattern was within another subpattern. For example, it looped when
1691        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1692        condition was not nested. This bug has been fixed.
1694    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1695        past the start of the subject in the presence of bytes with the top bit
1696        set, for example "\x8aBCD".
1698    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1699        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1701    14. Optimized (?!) to (*FAIL).
1703    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1704        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1705        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1706        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1707        does: it's just the validity check that is more restrictive.
1709    16. Inserted checks for integer overflows during escape sequence (backslash)
1710        processing, and also fixed erroneous offset values for syntax errors during
1711        backslash processing.
1713    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1714        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1716    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1717        caused an overrun.
1719    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1720        something other than just ASCII characters) inside a group that had an
1721        unlimited repeat caused a loop at compile time (while checking to see
1722        whether the group could match an empty string).
1724    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1725        [\P{Any}] did so. (Error in the code for printing property names.)
1727    21. An orphan \E inside a character class could cause a crash.
1729    22. A repeated capturing bracket such as (A)? could cause a wild memory
1730        reference during compilation.
1732    23. There are several functions in pcre_compile() that scan along a compiled
1733        expression for various reasons (e.g. to see if it's fixed length for look
1734        behind). There were bugs in these functions when a repeated \p or \P was
1735        present in the pattern. These operators have additional parameters compared
1736        with \d, etc, and these were not being taken into account when moving along
1737        the compiled data. Specifically:
1739        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1740            length.
1742        (b) An item such as \pL+ within a repeated group could cause crashes or
1743            loops.
1745        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1746            "reference to non-existent subpattern" error.
1748        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1750    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1751        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1753    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1755    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1756        character were causing crashes (broken optimization).
1758    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1759        \p or \P) caused a compile-time loop.
1761    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1762        break. For example, the unstudied pattern [\r\n]A does not match the string
1763        "\r\nA" because change 7.0/46 below moves the current point on by two
1764        characters after failing to match at the start. However, the pattern \nA
1765        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1766        the same is true. There doesn't seem any very clean way out of this, but
1767        what I have chosen to do makes the common cases work: PCRE now takes note
1768        of whether there can be an explicit match for \r or \n anywhere in the
1769        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1770        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1771        pattern has explicit CR or LF references.
1773    29. Added (*CR) etc for changing newline setting at start of pattern.
1776    Version 7.2 19-Jun-07
1777    ---------------------
1779     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1780        which is apparently normally available under Windows.
1782     2. Re-jig the pcregrep tests with different newline settings in an attempt
1783        to make them independent of the local environment's newline setting.
1785     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1787     4. Some of the "internals" tests were previously cut out when the link size
1788        was not 2, because the output contained actual offsets. The recent new
1789        "Z" feature of pcretest means that these can be cut out, making the tests
1790        usable with all link sizes.
1792     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1793        stack recursion. This gives a massive performance boost under BSD, but just
1794        a small improvement under Linux. However, it saves one field in the frame
1795        in all cases.
1797     6. Added more features from the forthcoming Perl 5.10:
1799        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1800            recursion call. It refers to the nth most recently opened parentheses.
1802        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1803            to be opened parentheses.
1805        (c) Conditions that refer to capturing parentheses can be specified
1806            relatively, for example, (?(-2)... or (?(+3)...
1808        (d) \K resets the start of the current match so that everything before
1809            is not part of it.
1811        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1813        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1814            reference syntax.
1816        (g) (?| introduces a group in which the numbering of parentheses in each
1817            alternative starts with the same number.
1819        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1821     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1824     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1825        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1826        for detecting groups that can match an empty string.
1828     9. A pattern with a very large number of alternatives (more than several
1829        hundred) was running out of internal workspace during the pre-compile
1830        phase, where pcre_compile() figures out how much memory will be needed. A
1831        bit of new cunning has reduced the workspace needed for groups with
1832        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1833        workspace instead of running out of the 4096 that are available.
1835    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1837    11. Applied patch from Google to remove an optimization that didn't quite work.
1838        The report of the bug said:
1840          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1841          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1842          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1844    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1845        it matched the wrong number of bytes.
1848    Version 7.1 24-Apr-07
1849    ---------------------
1851     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1852        that is more "standard", making use of automake and other Autotools. There
1853        is some re-arrangement of the files and adjustment of comments consequent
1854        on this.
1856     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1857        for recursive directory scanning broke on some systems because the files
1858        are not scanned in any specific order and on different systems the order
1859        was different. A call to "sort" has been inserted into RunGrepTest for the
1860        approprate test as a short-term fix. In the longer term there may be an
1861        alternative.
1863     3. I had an email from Eric Raymond about problems translating some of PCRE's
1864        man pages to HTML (despite the fact that I distribute HTML pages, some
1865        people do their own conversions for various reasons). The problems
1866        concerned the use of low-level troff macros .br and .in. I have therefore
1867        removed all such uses from the man pages (some were redundant, some could
1868        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1869        HTML has been updated to handle .nf/.fi and to complain if it encounters
1870        .br or .in.
1872     4. Updated comments in configure.ac that get placed in config.h.in and also
1873        arranged for config.h to be included in the distribution, with the name
1874        config.h.generic, for the benefit of those who have to compile without
1875        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1877     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1878        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1879        makevp.bat for the current PCRE, using the additional files
1880        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1882     6. A Windows user reported a minor discrepancy with test 2, which turned out
1883        to be caused by a trailing space on an input line that had got lost in his
1884        copy. The trailing space was an accident, so I've just removed it.
1886     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1887        that is needed.
1889     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1890        as "const" (a) because they are and (b) because it helps the PHP
1891        maintainers who have recently made a script to detect big data structures
1892        in the php code that should be moved to the .rodata section. I remembered
1893        to update Builducptable as well, so it won't revert if ucptable.h is ever
1894        re-created.
1896     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1897        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1898        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1899        support is not required. This saves 1.5-2K of code, which is important in
1900        some applications.
1902        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1903        so as not to refer to the tables, even though these functions will never be
1904        called when UTF-8 support is disabled. Otherwise there are problems with a
1905        shared library.
1907    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1909        (a) It was defining its arguments as char * instead of void *.
1911        (b) It was assuming that all moves were upwards in memory; this was true
1912            a long time ago when I wrote it, but is no longer the case.
1914        The emulated memove() is provided for those environments that have neither
1915        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1916        is clearly not the case, as these two bugs were recently reported.
1918    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1919        and Detrail to create the HTML documentation, the .txt form of the man
1920        pages, and it removes trailing spaces from listed files. It also creates
1921        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1922        case, it wraps all the #defines with #ifndefs. This script should be run
1923        before "make dist".
1925    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1926        with Unicode property support.
1928        (a) For a maximizing quantifier, if the two different cases of the
1929            character were of different lengths in their UTF-8 codings (there are
1930            some cases like this - I found 11), and the matching function had to
1931            back up over a mixture of the two cases, it incorrectly assumed they
1932            were both the same length.
1934        (b) When PCRE was configured to use the heap rather than the stack for
1935            recursion during matching, it was not correctly preserving the data for
1936            the other case of a UTF-8 character when checking ahead for a match
1937            while processing a minimizing repeat. If the check also involved
1938            matching a wide character, but failed, corruption could cause an
1939            erroneous result when trying to check for a repeat of the original
1940            character.
1942    13. Some tidying changes to the testing mechanism:
1944        (a) The RunTest script now detects the internal link size and whether there
1945            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1946            values substituted by "configure". (The RunGrepTest script already did
1947            this for UTF-8.) The configure.ac script no longer substitutes the
1948            relevant variables.
1950        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1951            with length and offset values. This means that the output is different
1952            for different internal link sizes. Test 2 is skipped for link sizes
1953            other than 2 because of this, bypassing the problem. Unfortunately,
1954            there was also a test in test 3 (the locale tests) that used /B and
1955            failed for link sizes other than 2. Rather than cut the whole test out,
1956            I have added a new /Z option to pcretest that replaces the length and
1957            offset values with spaces. This is now used to make test 3 independent
1958            of link size. (Test 2 will be tidied up later.)
1960    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1961        segmentation fault instead of returning the appropriate error message.
1963    15. In multiline mode when the newline sequence was set to "any", the pattern
1964        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1965        This doesn't seem right; it now treats the CRLF combination as the line
1966        ending, and so does not match in that case. It's only a pattern such as ^$
1967        that would hit this one: something like ^ABC$ would have failed after \r
1968        and then tried again after \r\n.
1970    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1971        in an attempt to make files that differ only in their line terminators
1972        compare equal. This works on Linux.
1974    17. Under certain error circumstances pcregrep might try to free random memory
1975        as it exited. This is now fixed, thanks to valgrind.
1977    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1978        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1979        was because its rules for how to advance for /g after matching an empty
1980        string at the end of a line did not allow for this case. They now check for
1981        it specially.
1983    20. pcretest is supposed to handle patterns and data of any length, by
1984        extending its buffers when necessary. It was getting this wrong when the
1985        buffer for a data line had to be extended.
1987    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1988        CRLF as a newline sequence.
1990    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1991        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1992        I have nevertheless tidied it up.
1994    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1996    24. Added a man page for pcre-config.
1999    Version 7.0 19-Dec-06
2000    ---------------------
2002     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
2003        moving to gcc 4.1.1.
2005     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
2006        sys/time.h, which is documented as needed for this function. It doesn't
2007        seem to matter on Linux, but it showed up on some releases of OS X.
2009     3. It seems that there are systems where bytes whose values are greater than
2010        127 match isprint() in the "C" locale. The "C" locale should be the
2011        default when a C program starts up. In most systems, only ASCII printing
2012        characters match isprint(). This difference caused the output from pcretest
2013        to vary, making some of the tests fail. I have changed pcretest so that:
2015        (a) When it is outputting text in the compiled version of a pattern, bytes
2016            other than 32-126 are always shown as hex escapes.
2018        (b) When it is outputting text that is a matched part of a subject string,
2019            it does the same, unless a different locale has been set for the match
2020            (using the /L modifier). In this case, it uses isprint() to decide.
2022     4. Fixed a major bug that caused incorrect computation of the amount of memory
2023        required for a compiled pattern when options that changed within the
2024        pattern affected the logic of the preliminary scan that determines the
2025        length. The relevant options are -x, and -i in UTF-8 mode. The result was
2026        that the computed length was too small. The symptoms of this bug were
2027        either the PCRE error "internal error: code overflow" from pcre_compile(),
2028        or a glibc crash with a message such as "pcretest: free(): invalid next
2029        size (fast)". Examples of patterns that provoked this bug (shown in
2030        pcretest format) are:
2032          /(?-x: )/x
2033          /(?x)(?-x: \s*#\s*)/
2034          /((?i)[\x{c0}])/8
2035          /(?i:[\x{c0}])/8
2037        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
2038        is now done differently.
2040     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
2041        wrapper classes; (b) implement a new function in the C++ scanner that is
2042        more efficient than the old way of doing things because it avoids levels of
2043        recursion in the regex matching; (c) add a paragraph to the documentation
2044        for the FullMatch() function.
2046     6. The escape sequence \n was being treated as whatever was defined as
2047        "newline". Not only was this contrary to the documentation, which states
2048        that \n is character 10 (hex 0A), but it also went horribly wrong when
2049        "newline" was defined as CRLF. This has been fixed.
2051     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
2052        was being set to -1 for the "end of line" case (supposedly a value that no
2053        character can have). Though this value is never used (the check for end of
2054        line is "zero bytes in current character"), it caused compiler complaints.
2055        I've changed it to 0xffffffff.
2057     8. In pcre_version.c, the version string was being built by a sequence of
2058        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
2059        string (as it is for production releases) called a macro with an empty
2060        argument. The C standard says the result of this is undefined. The gcc
2061        compiler treats it as an empty string (which was what was wanted) but it is
2062        reported that Visual C gives an error. The source has been hacked around to
2063        avoid this problem.
2065     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
2066        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
2067        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
2068        of them did).
2070    10. Originally, pcretest opened its input and output without "b"; then I was
2071        told that "b" was needed in some environments, so it was added for release
2072        5.0 to both the input and output. (It makes no difference on Unix-like
2073        systems.) Later I was told that it is wrong for the input on Windows. I've
2074        now abstracted the modes into two macros, to make it easier to fiddle with
2075        them, and removed "b" from the input mode under Windows.
2077    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
2079    12. Added -help and --help to pcretest as an official way of being reminded
2080        of the options.
2082    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
2083        and pcrecpp.cc because they annoy compilers at high warning levels.
2085    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
2087    15. Fixed an occurrence of == in configure.ac that should have been = (shell
2088        scripts are not C programs :-) and which was not noticed because it works
2089        on Linux.
2091    16. pcretest is supposed to handle any length of pattern and data line (as one
2092        line or as a continued sequence of lines) by extending its input buffer if
2093        necessary. This feature was broken for very long pattern lines, leading to
2094        a string of junk being passed to pcre_compile() if the pattern was longer
2095        than about 50K.
2097    17. I have done a major re-factoring of the way pcre_compile() computes the
2098        amount of memory needed for a compiled pattern. Previously, there was code
2099        that made a preliminary scan of the pattern in order to do this. That was
2100        OK when PCRE was new, but as the facilities have expanded, it has become
2101        harder and harder to keep it in step with the real compile phase, and there
2102        have been a number of bugs (see for example, 4 above). I have now found a
2103        cunning way of running the real compile function in a "fake" mode that
2104        enables it to compute how much memory it would need, while actually only
2105        ever using a few hundred bytes of working memory and without too many
2106        tests of the mode. This should make future maintenance and development
2107        easier. A side effect of this work is that the limit of 200 on the nesting
2108        depth of parentheses has been removed (though this was never a serious
2109        limitation, I suspect). However, there is a downside: pcre_compile() now
2110        runs more slowly than before (30% or more, depending on the pattern). I
2111        hope this isn't a big issue. There is no effect on runtime performance.
2113    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
2114        newline (only possible for the last line of a file) and it was a
2115        pattern that set a locale (followed by /Lsomething), pcretest crashed.
2117    19. Added additional timing features to pcretest. (1) The -tm option now times
2118        matching only, not compiling. (2) Both -t and -tm can be followed, as a
2119        separate command line item, by a number that specifies the number of
2120        repeats to use when timing. The default is 50000; this gives better
2121        precision, but takes uncomfortably long for very large patterns.
2123    20. Extended pcre_study() to be more clever in cases where a branch of a
2124        subpattern has no definite first character. For example, (a*|b*)[cd] would
2125        previously give no result from pcre_study(). Now it recognizes that the
2126        first character must be a, b, c, or d.
2128    21. There was an incorrect error "recursive call could loop indefinitely" if
2129        a subpattern (or the entire pattern) that was being tested for matching an
2130        empty string contained only one non-empty item after a nested subpattern.
2131        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
2132        incorrectly, because the \d was being skipped in the check.
2134    22. The pcretest program now has a new pattern option /B and a command line
2135        option -b, which is equivalent to adding /B to every pattern. This causes
2136        it to show the compiled bytecode, without the additional information that
2137        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
2138        is the same as /B/I).
2140    23. A new optimization is now able automatically to treat some sequences such
2141        as a*b as a*+b. More specifically, if something simple (such as a character
2142        or a simple class like \d) has an unlimited quantifier, and is followed by
2143        something that cannot possibly match the quantified thing, the quantifier
2144        is automatically "possessified".
2146    24. A recursive reference to a subpattern whose number was greater than 39
2147        went wrong under certain circumstances in UTF-8 mode. This bug could also
2148        have affected the operation of pcre_study().
2150    25. Realized that a little bit of performance could be had by replacing
2151        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
2153    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
2155    27. Possessive quantifiers such as a++ were previously implemented by turning
2156        them into atomic groups such as ($>a+). Now they have their own opcodes,
2157        which improves performance. This includes the automatically created ones
2158        from 23 above.
2160    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
2161        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
2162        the first matched character to be a colon. This applied both to named and
2163        numbered groups.
2165    29. The ucpinternal.h header file was missing its idempotency #ifdef.
2167    30. I was sent a "project" file called libpcre.a.dev which I understand makes
2168        building PCRE on Windows easier, so I have included it in the distribution.
2170    31. There is now a check in pcretest against a ridiculously large number being
2171        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
2172        loop, the loop is abandoned.
2174    32. Forward references to subpatterns in conditions such as (?(2)...) where
2175        subpattern 2 is defined later cause pcre_compile() to search forwards in
2176        the pattern for the relevant set of parentheses. This search went wrong
2177        when there were unescaped parentheses in a character class, parentheses
2178        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
2180    33. "Subroutine" calls and backreferences were previously restricted to
2181        referencing subpatterns earlier in the regex. This restriction has now
2182        been removed.
2184    34. Added a number of extra features that are going to be in Perl 5.10. On the
2185        whole, these are just syntactic alternatives for features that PCRE had
2186        previously implemented using the Python syntax or my own invention. The
2187        other formats are all retained for compatibility.
2189        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
2190            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
2191            also .NET compatible.
2193        (b) A recursion or subroutine call to a named group can now be defined as
2194            (?&name) as well as (?P>name).
2196        (c) A backreference to a named group can now be defined as \k<name> or
2197            \k'name' as well as (?P=name). The new forms, as well as being in Perl
2198            5.10, are also .NET compatible.
2200        (d) A conditional reference to a named group can now use the syntax
2201            (?(<name>) or (?('name') as well as (?(name).
2203        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
2204            groups (named and numbered) that are never evaluated inline, but can be
2205            called as "subroutines" from elsewhere. In effect, the DEFINE condition
2206            is always false. There may be only one alternative in such a group.
2208        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
2209            as the simple (?(R). The condition is true only if the most recent
2210            recursion is that of the given number or name. It does not search out
2211            through the entire recursion stack.
2213        (g) The escape \gN or \g{N} has been added, where N is a positive or
2214            negative number, specifying an absolute or relative reference.
2216    35. Tidied to get rid of some further signed/unsigned compiler warnings and
2217        some "unreachable code" warnings.
2219    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
2220        things, this adds five new scripts.
2222    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
2223        There were also incompatibilities regarding the handling of \Q..\E inside
2224        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
2225        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
2227    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
2228        matches an empty string, and forcibly breaks the loop. There were bugs in
2229        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
2230        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
2231        separate and independent bugs (that affected different cases) have been
2232        fixed.
2234    39. Refactored the code to abolish the use of different opcodes for small
2235        capturing bracket numbers. This is a tidy that I avoided doing when I
2236        removed the limit on the number of capturing brackets for 3.5 back in 2001.
2237        The new approach is not only tidier, it makes it possible to reduce the
2238        memory needed to fix the previous bug (38).
2240    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
2241        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
2242        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
2243        mode.
2245    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
2246        report.
2248    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
2249        copy construction and assignment in the C++ wrapper.
2251    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
2252        couple of bugs that could have given wrong results in the "--newline=crlf"
2253        case.
2255    44. Added a number of casts and did some reorganization of signed/unsigned int
2256        variables following suggestions from Dair Grant. Also renamed the variable
2257        "this" as "item" because it is a C++ keyword.
2259    45. Arranged for dftables to add
2261          #include "pcre_internal.h"
2263        to pcre_chartables.c because without it, gcc 4.x may remove the array
2264        definition from the final binary if PCRE is built into a static library and
2265        dead code stripping is activated.
2267    46. For an unanchored pattern, if a match attempt fails at the start of a
2268        newline sequence, and the newline setting is CRLF or ANY, and the next two
2269        characters are CRLF, advance by two characters instead of one.
2272    Version 6.7 04-Jul-06
2273    ---------------------
2275     1. In order to handle tests when input lines are enormously long, pcretest has
2276        been re-factored so that it automatically extends its buffers when
2277        necessary. The code is crude, but this _is_ just a test program. The
2278        default size has been increased from 32K to 50K.
2280     2. The code in pcre_study() was using the value of the re argument before
2281        testing it for NULL. (Of course, in any sensible call of the function, it
2282        won't be NULL.)
2284     3. The memmove() emulation function in pcre_internal.h, which is used on
2285        systems that lack both memmove() and bcopy() - that is, hardly ever -
2286        was missing a "static" storage class specifier.
2288     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2289        containing an extended class (one that cannot be represented by a bitmap
2290        because it contains high-valued characters or Unicode property items, e.g.
2291        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2292        pattern, but PCRE should not loop if you do not (it no longer does).
2293        [Detail: two cases were found: (a) a repeated subpattern containing an
2294        extended class; (b) a recursive reference to a subpattern that followed a
2295        previous extended class. It wasn't skipping over the extended class
2296        correctly when UTF-8 mode was not set.]
2298     5. A negated single-character class was not being recognized as fixed-length
2299        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2300        compile error "lookbehind assertion is not fixed length".
2302     6. The RunPerlTest auxiliary script was showing an unexpected difference
2303        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2304        write a Perl script that can interpret lines of an input file either as
2305        byte characters or as UTF-8, which is what "perltest" was being required to
2306        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2307        can't do is switch easily at run time between having the "use utf8;" pragma
2308        or not. In the end, I fudged it by using the RunPerlTest script to insert
2309        "use utf8;" explicitly for the UTF-8 tests.
2311     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2312        the end of the subject string, contrary to the documentation and to what
2313        Perl does. This was true of both matching functions. Now it matches only at
2314        the start of the subject and immediately after *internal* newlines.
2316     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2317        a pointer to an int instead of a pointer to an unsigned long int. This
2318        caused problems on 64-bit systems.
2320     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2321        instance of the 'standard' template library not being so standard".
2323    10. There was no check on the number of named subpatterns nor the maximum
2324        length of a subpattern name. The product of these values is used to compute
2325        the size of the memory block for a compiled pattern. By supplying a very
2326        long subpattern name and a large number of named subpatterns, the size
2327        computation could be caused to overflow. This is now prevented by limiting
2328        the length of names to 32 characters, and the number of named subpatterns
2329        to 10,000.
2331    11. Subpatterns that are repeated with specific counts have to be replicated in
2332        the compiled pattern. The size of memory for this was computed from the
2333        length of the subpattern and the repeat count. The latter is limited to
2334        65535, but there was no limit on the former, meaning that integer overflow
2335        could in principle occur. The compiled length of a repeated subpattern is
2336        now limited to 30,000 bytes in order to prevent this.
2338    12. Added the optional facility to have named substrings with the same name.
2340    13. Added the ability to use a named substring as a condition, using the
2341        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2342        are numbers (not recommended). Forward references are permitted.
2344    14. Added forward references in named backreferences (if you see what I mean).
2346    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2347        pattern could run off the end of the subject. For example, the pattern
2348        "(?s)(.{1,5})"8 did this with the subject "ab".
2350    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2351        PCRE_CASELESS was set when matching characters that were quantified with ?
2352        or *.
2354    17. A character class other than a single negated character that had a minimum
2355        but no maximum quantifier - for example [ab]{6,} - was not handled
2356        correctly by pce_dfa_exec(). It would match only one character.
2358    18. A valid (though odd) pattern that looked like a POSIX character
2359        class but used an invalid character after [ (for example [[,abc,]]) caused
2360        pcre_compile() to give the error "Failed: internal error: code overflow" or
2361        in some cases to crash with a glibc free() error. This could even happen if
2362        the pattern terminated after [[ but there just happened to be a sequence of
2363        letters, a binary zero, and a closing ] in the memory that followed.
2365    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2366        over the years. Originally (before any Unicode support), just the bottom 8
2367        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2368        output from "man perlunicode" includes this:
2370          The regular expression compiler produces polymorphic opcodes.  That
2371          is, the pattern adapts to the data and automatically switches to
2372          the Unicode character scheme when presented with Unicode data--or
2373          instead uses a traditional byte scheme when presented with byte
2374          data.
2376        Sadly, a wide octal escape does not cause a switch, and in a string with
2377        no other multibyte characters, these octal escapes are treated as before.
2378        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2379        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2380        Unicode string.
2382        I have not perpetrated such confusion in PCRE. Up till now, it took just
2383        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2384        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2385        translate to the appropriate multibyte character.
2387    29. Applied some refactoring to reduce the number of warnings from Microsoft
2388        and Borland compilers. This has included removing the fudge introduced
2389        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2390        a warning about an unused variable.
2392    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2393        characters since release 4.0, because Perl (from release 5.004) does not.
2394        [Or at least, is documented not to: some releases seem to be in conflict
2395        with the documentation.] However, when a pattern was studied with
2396        pcre_study() and all its branches started with \s, PCRE still included VT
2397        as a possible starting character. Of course, this did no harm; it just
2398        caused an unnecessary match attempt.
2400    22. Removed a now-redundant internal flag bit that recorded the fact that case
2401        dependency changed within the pattern. This was once needed for "required
2402        byte" processing, but is no longer used. This recovers a now-scarce options
2403        bit. Also moved the least significant internal flag bit to the most-
2404        significant bit of the word, which was not previously used (hangover from
2405        the days when it was an int rather than a uint) to free up another bit for
2406        the future.
2408    23. Added support for CRLF line endings as well as CR and LF. As well as the
2409        default being selectable at build time, it can now be changed at runtime
2410        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2411        specify that it is scanning data with non-default line endings.
2413    24. Changed the definition of CXXLINK to make it agree with the definition of
2414        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2416    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2417        recursions. This makes a big different to stack usage for some patterns.
2419    26. If a subpattern containing a named recursion or subroutine reference such
2420        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2421        the space required for the compiled pattern went wrong and gave too small a
2422        value. Depending on the environment, this could lead to "Failed: internal
2423        error: code overflow at offset 49" or "glibc detected double free or
2424        corruption" errors.
2426    27. Applied patches from Google (a) to support the new newline modes and (b) to
2427        advance over multibyte UTF-8 characters in GlobalReplace.
2429    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2430        difference for some implementation of PCRE in some Windows version.
2432    29. Added some extra testing facilities to pcretest:
2434        \q<number>   in a data line sets the "match limit" value
2435        \Q<number>   in a data line sets the "match recursion limt" value
2436        -S <number>  sets the stack size, where <number> is in megabytes
2438        The -S option isn't available for Windows.
2441    Version 6.6 06-Feb-06
2442    ---------------------
2444     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2445        in pcreposix.h. I have copied the definition from pcre.h.
2447     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2448        because pcre.h is no longer a built file.
2450     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2451        not normally included in the compiled code.
2454    Version 6.5 01-Feb-06
2455    ---------------------
2457     1. When using the partial match feature with pcre_dfa_exec(), it was not
2458        anchoring the second and subsequent partial matches at the new starting
2459        point. This could lead to incorrect results. For example, with the pattern
2460        /1234/, partially matching against "123" and then "a4" gave a match.
2462     2. Changes to pcregrep:
2464        (a) All non-match returns from pcre_exec() were being treated as failures
2465            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2466            error message is output. Some extra information is given for the
2467            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2468            probably the only errors that are likely to be caused by users (by
2469            specifying a regex that has nested indefinite repeats, for instance).
2470            If there are more than 20 of these errors, pcregrep is abandoned.
2472        (b) A binary zero was treated as data while matching, but terminated the
2473            output line if it was written out. This has been fixed: binary zeroes
2474            are now no different to any other data bytes.
2476        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2477            used to set a locale for matching. The --locale=xxxx long option has
2478            been added (no short equivalent) to specify a locale explicitly on the
2479            pcregrep command, overriding the environment variables.
2481        (d) When -B was used with -n, some line numbers in the output were one less
2482            than they should have been.
2484        (e) Added the -o (--only-matching) option.
2486        (f) If -A or -C was used with -c (count only), some lines of context were
2487            accidentally printed for the final match.
2489        (g) Added the -H (--with-filename) option.
2491        (h) The combination of options -rh failed to suppress file names for files
2492            that were found from directory arguments.
2494        (i) Added the -D (--devices) and -d (--directories) options.
2496        (j) Added the -F (--fixed-strings) option.
2498        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2500        (l) Added the --colo(u)r option.
2502        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2503            is not present by default.
2505     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2506        items such as (?R) or (?1), when the recursion could match a number of
2507        alternatives. If it matched one of the alternatives, but subsequently,
2508        outside the recursion, there was a failure, the code tried to back up into
2509        the recursion. However, because of the way PCRE is implemented, this is not
2510        possible, and the result was an incorrect result from the match.
2512        In order to prevent this happening, the specification of recursion has
2513        been changed so that all such subpatterns are automatically treated as
2514        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2516     4. I had overlooked the fact that, in some locales, there are characters for
2517        which isalpha() is true but neither isupper() nor islower() are true. In
2518        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2519        and ordfeminine) are like this. This affected the treatment of \w and \W
2520        when they appeared in character classes, but not when they appeared outside
2521        a character class. The bit map for "word" characters is now created
2522        separately from the results of isalnum() instead of just taking it from the
2523        upper, lower, and digit maps. (Plus the underscore character, of course.)
2525     5. The above bug also affected the handling of POSIX character classes such as
2526        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2527        permanent tables. Instead, the bit maps for such a class were previously
2528        created as the appropriate unions of the upper, lower, and digit bitmaps.
2529        Now they are created by subtraction from the [[:word:]] class, which has
2530        its own bitmap.
2532     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2533        It is created by subtracting the vertical space characters (\x09, \x0a,
2534        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2535        subtraction was done in the overall bitmap for a character class, meaning
2536        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2537        be recognized. This bug has been fixed.
2539     7. Patches from the folks at Google:
2541          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2542          real life, but is still worth protecting against".
2544          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2545          regular expressions".
2547          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2548          have it.
2550          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2551          "configure" and the latter not, in order to fix a problem somebody had
2552          with compiling the Arg class on HP-UX.
2554          (e) Improve the error-handling of the C++ wrapper a little bit.
2556          (f) New tests for checking recursion limiting.
2558     8. The pcre_memmove() function, which is used only if the environment does not
2559        have a standard memmove() function (and is therefore rarely compiled),
2560        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2561        returning a result (though PCRE never actually uses the result).
2563     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2564        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2565        returned instead of calling malloc() with an overflowing number that would
2566        most likely cause subsequent chaos.
2568    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2570    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2571        with this option is matched, the nmatch and pmatch options of regexec() are
2572        ignored.
2574    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2575        provided in case anyone wants to the the POSIX interface with UTF-8
2576        strings.
2578    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2579        C++ linking (needed for some HP-UX environments).
2581    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2582        (unused parameter) and in the pcre_printint() function (omitted "default"
2583        switch label when the default is to do nothing).
2585    15. Added some code to make it possible, when PCRE is compiled as a C++
2586        library, to replace subject pointers for pcre_exec() with a smart pointer
2587        class, thus making it possible to process discontinuous strings.
2589    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2590        much the same function. They were added by different people who were trying
2591        to make PCRE easy to compile on non-Unix systems. It has been suggested
2592        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2593        for compiling on Windows systems. I have therefore replaced it with
2594        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2595        defaults to "extern" for C or "extern C" for C++, which works fine on
2596        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2597        SCOPE with something explicit in config.h. In addition:
2599        (a) pcreposix.h still had just "extern" instead of either of these macros;
2600            I have replaced it with PCRE_DATA_SCOPE.
2602        (b) Functions such as _pcre_xclass(), which are internal to the library,
2603            but external in the C sense, all had PCRE_EXPORT in their definitions.
2604            This is apparently wrong for the Windows case, so I have removed it.
2605            (It makes no difference on Unix-like systems.)
2607    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2608        of recursive calls to match(). This is different to MATCH_LIMIT because
2609        that limits the total number of calls to match(), not all of which increase
2610        the depth of recursion. Limiting the recursion depth limits the amount of
2611        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2612        when PCRE is compiled, and changed at run time. A patch from Google adds
2613        this functionality to the C++ interface.
2615    18. Changes to the handling of Unicode character properties:
2617        (a) Updated the table to Unicode 4.1.0.
2619        (b) Recognize characters that are not in the table as "Cn" (undefined).
2621        (c) I revised the way the table is implemented to a much improved format
2622            which includes recognition of ranges. It now supports the ranges that
2623            are defined in UnicodeData.txt, and it also amalgamates other
2624            characters into ranges. This has reduced the number of entries in the
2625            table from around 16,000 to around 3,000, thus reducing its size
2626            considerably. I realized I did not need to use a tree structure after
2627            all - a binary chop search is just as efficient. Having reduced the
2628            number of entries, I extended their size from 6 bytes to 8 bytes to
2629            allow for more data.
2631        (d) Added support for Unicode script names via properties such as \p{Han}.
2633    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2634        matching that character.
2636    20. When matching a repeated Unicode property with a minimum greater than zero,
2637        (for example \pL{2,}), PCRE could look past the end of the subject if it
2638        reached it while seeking the minimum number of characters. This could
2639        happen only if some of the characters were more than one byte long, because
2640        there is a check for at least the minimum number of bytes.
2642    21. Refactored the implementation of \p and \P so as to be more general, to
2643        allow for more different types of property in future. This has changed the
2644        compiled form incompatibly. Anybody with saved compiled patterns that use
2645        \p or \P will have to recompile them.
2647    22. Added "Any" and "L&" to the supported property types.
2649    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2650        but give a compile time error if the value is greater than 0xff.
2652    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2653        accidentally not being installed or uninstalled.
2655    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2656        made were to insert the current release number. This seemed silly, because
2657        it made things harder for people building PCRE on systems that don't run
2658        "configure". I have turned pcre.h into a distributed file, no longer built
2659        by "configure", with the version identification directly included. There is
2660        no longer a pcre.h.in file.
2662        However, this change necessitated a change to the pcre-config script as
2663        well. It is built from pcre-config.in, and one of the substitutions was the
2664        release number. I have updated configure.ac so that ./configure now finds
2665        the release number by grepping pcre.h.
2667    26. Added the ability to run the tests under valgrind.
2670    Version 6.4 05-Sep-05
2671    ---------------------
2673     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2674        "--" to be printed when multiple files were scanned, even when none of the
2675        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2676        consider it to be a bug, and have restored the previous behaviour.
2678     2. A couple of code tidies to get rid of compiler warnings.
2680     3. The pcretest program used to cheat by referring to symbols in the library
2681        whose names begin with _pcre_. These are internal symbols that are not
2682        really supposed to be visible externally, and in some environments it is
2683        possible to suppress them. The cheating is now confined to including
2684        certain files from the library's source, which is a bit cleaner.
2686     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2687        file's purpose clearer.
2689     5. Reorganized pcre_ucp_findchar().
2692    Version 6.3 15-Aug-05
2693    ---------------------
2695     1. The file libpcre.pc.in did not have general read permission in the tarball.
2697     2. There were some problems when building without C++ support:
2699        (a) If C++ support was not built, "make install" and "make test" still
2700            tried to test it.
2702        (b) There were problems when the value of CXX was explicitly set. Some
2703            changes have been made to try to fix these, and ...
2705        (c) --disable-cpp can now be used to explicitly disable C++ support.
2707        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2708            backslash in a target when C++ was disabled. This confuses some
2709            versions of "make", apparently. Using an intermediate variable solves
2710            this. (Same for CPP_LOBJ.)
2712     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2713        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2714        necessary on certain architectures.
2716     4. Added a setting of -export-symbols-regex to the link command to remove
2717        those symbols that are exported in the C sense, but actually are local
2718        within the library, and not documented. Their names all begin with
2719        "_pcre_". This is not a perfect job, because (a) we have to except some
2720        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2721        available (and never for static libraries). I have made a note to try to
2722        find a way round (a) in the future.
2725    Version 6.2 01-Aug-05
2726    ---------------------
2728     1. There was no test for integer overflow of quantifier values. A construction
2729        such as {1111111111111111} would give undefined results. What is worse, if
2730        a minimum quantifier for a parenthesized subpattern overflowed and became
2731        negative, the calculation of the memory size went wrong. This could have
2732        led to memory overwriting.
2734     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2736     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2737        operating environments where this matters.
2739     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2740        PCRE options from within the C++ wrapper.
2742     5. Named capturing subpatterns were not being correctly counted when a pattern
2743        was compiled. This caused two problems: (a) If there were more than 100
2744        such subpatterns, the calculation of the memory needed for the whole
2745        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2746        back references of the form \12, where the number was greater than 9, were
2747        not recognized as back references, even though there were sufficient
2748        previous subpatterns.
2750     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2751        versions of gcc, e.g. 2.95.4.
2754    Version 6.1 21-Jun-05
2755    ---------------------
2757     1. There was one reference to the variable "posix" in pcretest.c that was not
2758        surrounded by "#if !defined NOPOSIX".
2760     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2761        the cross-check on the old pcre_info() function, for the benefit of the
2762        cut-down version of PCRE that is currently imported into Exim.
2764     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2765        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2766        patterns that start (?i) but I don't think that matters. The use of (?i) is
2767        just an example; this all applies to the other options as well.
2769     4. Since libtool seems to echo the compile commands it is issuing, the output
2770        from "make" can be reduced a bit by putting "@" in front of each libtool
2771        compile command.
2773     5. Patch from the folks at Google for configure.in to be a bit more thorough
2774        in checking for a suitable C++ installation before trying to compile the
2775        C++ stuff. This should fix a reported problem when a compiler was present,
2776        but no suitable headers.
2778     6. The man pages all had just "PCRE" as their title. I have changed them to
2779        be the relevant file name. I have also arranged that these names are
2780        retained in the file doc/pcre.txt, which is a concatenation in text format
2781        of all the man pages except the little individual ones for each function.
2783     7. The NON-UNIX-USE file had not been updated for the different set of source
2784        files that come with release 6. I also added a few comments about the C++
2785        wrapper.
2788    Version 6.0 07-Jun-05
2789    ---------------------
2791     1. Some minor internal re-organization to help with my DFA experiments.
2793     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2794        didn't matter for the library itself when fully configured, but did matter
2795        when compiling without UCP support, or within Exim, where the ucp files are
2796        not imported.
2798     3. Refactoring of the library code to split up the various functions into
2799        different source modules. The addition of the new DFA matching code (see
2800        below) to a single monolithic source would have made it really too
2801        unwieldy, quite apart from causing all the code to be include in a
2802        statically linked application, when only some functions are used. This is
2803        relevant even without the DFA addition now that patterns can be compiled in
2804        one application and matched in another.
2806        The downside of splitting up is that there have to be some external
2807        functions and data tables that are used internally in different modules of
2808        the library but which are not part of the API. These have all had their
2809        names changed to start with "_pcre_" so that they are unlikely to clash
2810        with other external names.
2812     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2813        a different (DFA) algorithm. Although it is slower than the original
2814        function, it does have some advantages for certain types of matching
2815        problem.
2817     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2818        including restarting after a partial match.
2820     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2821        defined when compiling for Windows was sent to me. I have put it into the
2822        code, though I have no means of testing or verifying it.
2824     7. Added the pcre_refcount() auxiliary function.
2826     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2827        match before or at the first newline in the subject string. In pcretest,
2828        the /f option on a pattern can be used to set this.
2830     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2831        would behave wrongly. This has been present in PCRE since release 4.0.
2833    10. A number of changes to the pcregrep command:
2835        (a) Refactored how -x works; insert ^(...)$ instead of setting
2836            PCRE_ANCHORED and checking the length, in preparation for adding
2837            something similar for -w.
2839        (b) Added the -w (match as a word) option.
2841        (c) Refactored the way lines are read and buffered so as to have more
2842            than one at a time available.
2844        (d) Implemented a pcregrep test script.
2846        (e) Added the -M (multiline match) option. This allows patterns to match
2847            over several lines of the subject. The buffering ensures that at least
2848            8K, or the rest of the document (whichever is the shorter) is available
2849            for matching (and similarly the previous 8K for lookbehind assertions).
2851        (f) Changed the --help output so that it now says
2853              -w, --word-regex(p)
2855            instead of two lines, one with "regex" and the other with "regexp"
2856            because that confused at least one person since the short forms are the
2857            same. (This required a bit of code, as the output is generated
2858            automatically from a table. It wasn't just a text change.)
2860        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2861            option but starts with a hyphen. Could be a pattern or a path name
2862            starting with a hyphen, for instance.
2864        (h) "-" can be given as a file name to represent stdin.
2866        (i) When file names are being printed, "(standard input)" is used for
2867            the standard input, for compatibility with GNU grep. Previously
2868            "<stdin>" was used.
2870        (j) The option --label=xxx can be used to supply a name to be used for
2871            stdin when file names are being printed. There is no short form.
2873        (k) Re-factored the options decoding logic because we are going to add
2874            two more options that take data. Such options can now be given in four
2875            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2877        (l) Added the -A, -B, and -C options for requesting that lines of context
2878            around matches be printed.
2880        (m) Added the -L option to print the names of files that do not contain
2881            any matching lines, that is, the complement of -l.
2883        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2884            continue to scan other files.
2886        (o) The -s option was incorrectly implemented. For compatibility with other
2887            greps, it now suppresses the error message for a non-existent or non-
2888            accessible file (but not the return code). There is a new option called
2889            -q that suppresses the output of matching lines, which was what -s was
2890            previously doing.
2892        (p) Added --include and --exclude options to specify files for inclusion
2893            and exclusion when recursing.
2895    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2896        Hopefully, it now does.
2898    12. Missing cast in pcre_study().
2900    13. Added an "uninstall" target to the makefile.
2902    14. Replaced "extern" in the function prototypes in Makefile.in with
2903        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2904        world, but is set differently for Windows.
2906    15. Added a second compiling function called pcre_compile2(). The only
2907        difference is that it has an extra argument, which is a pointer to an
2908        integer error code. When there is a compile-time failure, this is set
2909        non-zero, in addition to the error test pointer being set to point to an
2910        error message. The new argument may be NULL if no error number is required
2911        (but then you may as well call pcre_compile(), which is now just a
2912        wrapper). This facility is provided because some applications need a
2913        numeric error indication, but it has also enabled me to tidy up the way
2914        compile-time errors are handled in the POSIX wrapper.
2916    16. Added VPATH=.libs to the makefile; this should help when building with one
2917        prefix path and installing with another. (Or so I'm told by someone who
2918        knows more about this stuff than I do.)
2920    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2921        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2922        match everything, including newlines. This is not POSIX-compatible, but
2923        somebody wanted the feature. From pcretest it can be activated by using
2924        both the P and the s flags.
2926    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2928    19. libpcre.pc was being incorrectly installed as executable.
2930    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2931        it now also looks for '\r' so that it will work unmodified on Windows.
2933    21. Added Google's contributed C++ wrapper to the distribution.
2935    22. Added some untidy missing memory free() calls in pcretest, to keep
2936        Electric Fence happy when testing.
2940    Version 5.0 13-Sep-04
2941    ---------------------
2943     1. Internal change: literal characters are no longer packed up into items
2944        containing multiple characters in a single byte-string. Each character
2945        is now matched using a separate opcode. However, there may be more than one
2946        byte in the character in UTF-8 mode.
2948     2. The pcre_callout_block structure has two new fields: pattern_position and
2949        next_item_length. These contain the offset in the pattern to the next match
2950        item, and its length, respectively.
2952     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2953        insertion of callouts before each pattern item. Added the /C option to
2954        pcretest to make use of this.
2956     4. On the advice of a Windows user, the lines
2958          #if defined(_WIN32) || defined(WIN32)
2959          _setmode( _fileno( stdout ), 0x8000 );
2960          #endif  /* defined(_WIN32) || defined(WIN32) */
2962        have been added to the source of pcretest. This apparently does useful
2963        magic in relation to line terminators.
2965     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2966        for the benefit of those environments where the "b" makes a difference.
2968     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2969        to know about it. I have put a hack into configure.in that adds in code
2970        to set GCC=yes if CC=icc. This seems to end up at a point in the
2971        generated configure script that is early enough to affect the setting of
2972        compiler options, which is what is needed, but I have no means of testing
2973        whether it really works. (The user who reported this had patched the
2974        generated configure script, which of course I cannot do.)
2976        LATER: After change 22 below (new libtool files), the configure script
2977        seems to know about icc (and also ecc). Therefore, I have commented out
2978        this hack in configure.in.
2980     7. Added support for pkg-config (2 patches were sent in).
2982     8. Negated POSIX character classes that used a combination of internal tables
2983        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2984        [[:^ascii]]. Typically, they would match almost any characters. The other
2985        POSIX classes were not broken in this way.
2987     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2988        to find the match, as PCRE was deluded into thinking that the match had to
2989        start at the start point or following a newline. The same bug applied to
2990        patterns with negative forward assertions or any backward assertions
2991        preceding ".*" at the start, unless the pattern required a fixed first
2992        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2994    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2995        starting at the last subject character, bytes beyond the end of the subject
2996        string were read.
2998    11. Renamed the variable "class" as "classbits" to make life easier for C++
2999        users. (Previously there was a macro definition, but it apparently wasn't
3000        enough.)
3002    12. Added the new field "tables" to the extra data so that tables can be passed
3003        in at exec time, or the internal tables can be re-selected. This allows
3004        a compiled regex to be saved and re-used at a later time by a different
3005        program that might have everything at different addresses.
3007    13. Modified the pcre-config script so that, when run on Solaris, it shows a
3008        -R library as well as a -L library.
3010    14. The debugging options of pcretest (-d on the command line or D on a
3011        pattern) showed incorrect output for anything following an extended class
3012        that contained multibyte characters and which was followed by a quantifier.
3014    15. Added optional support for general category Unicode character properties
3015        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
3016        support. It adds about 90K to the size of the library. The meanings of the
3017        inbuilt class escapes such as \d and \s have NOT been changed.
3019    16. Updated pcredemo.c to include calls to free() to release the memory for the
3020        compiled pattern.
3022    17. The generated file chartables.c was being created in the source directory
3023        instead of in the building directory. This caused the build to fail if the
3024        source directory was different from the building directory, and was
3025        read-only.
3027    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
3028        file. No doubt somebody will tell me if they don't make sense... Also added
3029        Dan Mooney's comments about building on OpenVMS.
3031    19. Added support for partial matching via the PCRE_PARTIAL option for
3032        pcre_exec() and the \P data escape in pcretest.
3034    20. Extended pcretest with 3 new pattern features:
3036        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
3037              write the compiled pattern to the file whose name is "rest-of-line".
3038              This is a straight binary dump of the data, with the saved pointer to
3039              the character tables forced to be NULL. The study data, if any, is
3040              written too. After writing, pcretest reads a new pattern.
3042        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
3043              compiled pattern from the given file. There must not be any
3044              occurrences of "<" in the file name (pretty unlikely); if there are,
3045              pcretest will instead treat the initial "<" as a pattern delimiter.
3046              After reading in the pattern, pcretest goes on to read data lines as
3047              usual.
3049        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
3050              and 16-bit fields in a compiled pattern, to simulate a pattern that
3051              was compiled on a host of opposite endianness.
3053    21. The pcre-exec() function can now cope with patterns that were compiled on
3054        hosts of opposite endianness, with this restriction:
3056          As for any compiled expression that is saved and used later, the tables
3057          pointer field cannot be preserved; the extra_data field in the arguments
3058          to pcre_exec() should be used to pass in a tables address if a value
3059          other than the default internal tables were used at compile time.
3061    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
3062        now diagnosed as an error. Previously, most of the time, a negative number
3063        would have been treated as zero, but if in addition "ovector" was passed as
3064        NULL, a crash could occur.
3066    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
3067        new versions from the libtool 1.5 distribution (the last one is a copy of
3068        a file called libtool.m4). This seems to have fixed the need to patch
3069        "configure" to support Darwin 1.3 (which I used to do). However, I still
3070        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
3071        workstation).
3073    24. Changed the PCRE licence to be the more standard "BSD" licence.
3076    Version 4.5 01-Dec-03
3077    ---------------------
3079     1. There has been some re-arrangement of the code for the match() function so
3080        that it can be compiled in a version that does not call itself recursively.
3081        Instead, it keeps those local variables that need separate instances for
3082        each "recursion" in a frame on the heap, and gets/frees frames whenever it
3083        needs to "recurse". Keeping track of where control must go is done by means
3084        of setjmp/longjmp. The whole thing is implemented by a set of macros that
3085        hide most of the details from the main code, and operates only if
3086        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
3087        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
3088        operating.
3090        To make it easier for callers to provide specially tailored get/free
3091        functions for this usage, two new functions, pcre_stack_malloc, and
3092        pcre_stack_free, are used. They are always called in strict stacking order,
3093        and the size of block requested is always the same.
3095        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
3096        PCRE has been compiled to use the stack or the heap for recursion. The
3097        -C option of pcretest uses this to show which version is compiled.
3099        A new data escape \S, is added to pcretest; it causes the amounts of store
3100        obtained and freed by both kinds of malloc/free at match time to be added
3101        to the output.
3103     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
3104        what's available on my current Linux desktop machine.
3106     3. When matching a UTF-8 string, the test for a valid string at the start has
3107        been extended. If start_offset is not zero, PCRE now checks that it points
3108        to a byte that is the start of a UTF-8 character. If not, it returns
3109        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
3110        this is necessary because there may be backward assertions in the pattern.
3111        When matching the same subject several times, it may save resources to use
3112        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
3114     4. The code for checking the validity of UTF-8 strings has been tightened so
3115        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
3116        containing "overlong sequences".
3118     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
3119        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
3120        should have been "&", but it just so happened that all the cases this let
3121        through by mistake were picked up later in the function.
3123     6. I had used a variable called "isblank" - this is a C99 function, causing
3124        some compilers to warn. To avoid this, I renamed it (as "blankclass").
3126     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
3127        prompting; (b) run "./pcretest /dev/null" at the start of the test script
3128        so the version is shown; (c) stop "make test" echoing "./RunTest".
3130     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
3132     9. The prototype for memmove() for systems that don't have it was using
3133        size_t, but the inclusion of the header that defines size_t was later. I've
3134        moved the #includes for the C headers earlier to avoid this.
3136    10. Added some adjustments to the code to make it easier to compiler on certain
3137        special systems:
3139          (a) Some "const" qualifiers were missing.
3140          (b) Added the macro EXPORT before all exported functions; by default this
3141              is defined to be empty.
3142          (c) Changed the dftables auxiliary program (that builds chartables.c) so
3143              that it reads its output file name as an argument instead of writing
3144              to the standard output and assuming this can be redirected.
3146    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
3147        class containing characters with values greater than 255, PCRE compilation
3148        went into a loop.
3150    12. A recursive reference to a subpattern that was within another subpattern
3151        that had a minimum quantifier of zero caused PCRE to crash. For example,
3152        (x(y(?2))z)? provoked this bug with a subject that got as far as the
3153        recursion. If the recursively-called subpattern itself had a zero repeat,
3154        that was OK.
3156    13. In pcretest, the buffer for reading a data line was set at 30K, but the
3157        buffer into which it was copied (for escape processing) was still set at
3158        1024, so long lines caused crashes.
3160    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
3161        "internal error: code overflow...". This applied to any character class
3162        that was followed by a possessive quantifier.
3164    15. Modified the Makefile to add libpcre.la as a prerequisite for
3165        libpcreposix.la because I was told this is needed for a parallel build to
3166        work.
3168    16. If a pattern that contained .* following optional items at the start was
3169        studied, the wrong optimizing data was generated, leading to matching
3170        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
3171        matching string must start with a or b or c. The correct conclusion for
3172        this pattern is that a match can start with any character.
3175    Version 4.4 13-Aug-03
3176    ---------------------
3178     1. In UTF-8 mode, a character class containing characters with values between
3179        127 and 255 was not handled correctly if the compiled pattern was studied.
3180        In fixing this, I have also improved the studying algorithm for such
3181        classes (slightly).
3183     2. Three internal functions had redundant arguments passed to them. Removal
3184        might give a very teeny performance improvement.
3186     3. Documentation bug: the value of the capture_top field in a callout is *one
3187        more than* the number of the hightest numbered captured substring.
3189     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
3190        in incorrectly linking with a previously installed version. They now link
3191        explicitly with libpcre.la.
3193     5. configure.in no longer needs to recognize Cygwin specially.
3195     6. A problem in pcre.in for Windows platforms is fixed.
3197     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
3198        pcretest, it used to include the size of the study block as part of its
3199        output. Unfortunately, the structure contains a field that has a different
3200        size on different hardware architectures. This meant that the tests that
3201        showed this size failed. As the block is currently always of a fixed size,
3202        this information isn't actually particularly useful in pcretest output, so
3203        I have just removed it.
3205     8. Three pre-processor statements accidentally did not start in column 1.
3206        Sadly, there are *still* compilers around that complain, even though
3207        standard C has not required this for well over a decade. Sigh.
3209     9. In pcretest, the code for checking callouts passed small integers in the
3210        callout_data field, which is a void * field. However, some picky compilers
3211        complained about the casts involved for this on 64-bit systems. Now
3212        pcretest passes the address of the small integer instead, which should get
3213        rid of the warnings.
3215    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
3216        both compile and run time, and gives an error if an invalid UTF-8 sequence
3217        is found. There is a option for disabling this check in cases where the
3218        string is known to be correct and/or the maximum performance is wanted.
3220    11. In response to a bug report, I changed one line in Makefile.in from
3222            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
3223        to
3224            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
3226        to look similar to other lines, but I have no way of telling whether this
3227        is the right thing to do, as I do not use Windows. No doubt I'll get told
3228        if it's wrong...
3231    Version 4.3 21-May-03
3232    ---------------------
3234    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
3235       Makefile.
3237    2. Some refactoring to improve the quality of the code:
3239       (i)   The utf8_table... variables are now declared "const".
3241       (ii)  The code for \cx, which used the "case flipping" table to upper case
3242             lower case letters, now just substracts 32. This is ASCII-specific,
3243             but the whole concept of \cx is ASCII-specific, so it seems
3244             reasonable.
3246       (iii) PCRE was using its character types table to recognize decimal and
3247             hexadecimal digits in the pattern. This is silly, because it handles
3248             only 0-9, a-f, and A-F, but the character types table is locale-
3249             specific, which means strange things might happen. A private
3250             table is now used for this - though it costs 256 bytes, a table is
3251             much faster than multiple explicit tests. Of course, the standard
3252             character types table is still used for matching digits in subject
3253             strings against \d.
3255       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
3256             ending in _t are). So I've renamed it as ESC_tee.
3258    3. The first argument for regexec() in the POSIX wrapper should have been
3259       defined as "const".
3261    4. Changed pcretest to use malloc() for its buffers so that they can be
3262       Electric Fenced for debugging.
3264    5. There were several places in the code where, in UTF-8 mode, PCRE would try
3265       to read one or more bytes before the start of the subject string. Often this
3266       had no effect on PCRE's behaviour, but in some circumstances it could
3267       provoke a segmentation fault.
3269    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
3270       to try to read one or more bytes before the start of the subject string.
3272    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
3273       UTF-8 support could misbehave in various ways if the subject string
3274       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
3275       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
3276       back over UTF-8 characters.)
3279    Version 4.2 14-Apr-03
3280    ---------------------
3282    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
3284    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
3285         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
3286         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
3287         [WIN_PREFIX]: new variable, "cyg" for Cygwin
3288         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
3289           and BUILD_EXEEXT
3290         Note: automatic setting of the BUILD variables is not yet working
3291         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
3292           compile-time but not at link-time
3293         [LINK]: use for linking executables only
3294         make different versions for Windows and non-Windows
3295         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
3296           libraries
3297         [LINK_FOR_BUILD]: new variable
3298         [OBJEXT]: use throughout
3299         [EXEEXT]: use throughout
3300         <winshared>: new target
3301         <wininstall>: new target
3302         <dftables.o>: use native compiler
3303         <dftables>: use native linker
3304         <install>: handle Windows platform correctly
3305         <clean>: ditto
3306         <check>: ditto
3307         copy DLL to top builddir before testing
3309       As part of these changes, -no-undefined was removed again. This was reported
3310       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
3311       in any case.
3313    3. Some tidies to get rid of compiler warnings:
3315       . In the match_data structure, match_limit was an unsigned long int, whereas
3316         match_call_count was an int. I've made them both unsigned long ints.
3318       . In pcretest the fact that a const uschar * doesn't automatically cast to
3319         a void * provoked a warning.
3321       . Turning on some more compiler warnings threw up some "shadow" variables
3322         and a few more missing casts.
3324    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
3325       option, a class that contained a single character with a value between 128
3326       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
3328    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
3329       option, a class that contained several characters, but with at least one
3330       whose value was between 128 and 255 caused PCRE to crash.
3333    Version 4.1 12-Mar-03
3334    ---------------------
3336    1. Compiling with gcc -pedantic found a couple of places where casts were
3337    needed, and a string in dftables.c that was longer than standard compilers are
3338    required to support.
3340    2. Compiling with Sun's compiler found a few more places where the code could
3341    be tidied up in order to avoid warnings.
3343    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
3344    first of these names is deprecated in the latest Autoconf in favour of the name
3345    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
3346    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
3347    analogy I have changed it to CFLAGS_FOR_BUILD.
3349    4. Added -no-undefined to the linking command in the Makefile, because this is
3350    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
3351    linking step for the pcreposix library.
3353    5. PCRE was failing to diagnose the case of two named groups with the same
3354    name.
3356    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
3357    literal character that is needed in the subject for a match, and scans along to
3358    ensure that it is present before embarking on the full matching process. This
3359    saves time in cases of nested unlimited repeats that are never going to match.
3360    Problem: the scan can take a lot of time if the subject is very long (e.g.
3361    megabytes), thus penalizing straightforward matches. It is now done only if the
3362    amount of subject to be scanned is less than 1000 bytes.
3364    7. A lesser problem with the same optimization is that it was recording the
3365    first character of an anchored pattern as "needed", thus provoking a search
3366    right along the subject, even when the first match of the pattern was going to
3367    fail. The "needed" character is now not set for anchored patterns, unless it
3368    follows something in the pattern that is of non-fixed length. Thus, it still
3369    fulfils its original purpose of finding quick non-matches in cases of nested
3370    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
3373    Version 4.0 17-Feb-03
3374    ---------------------
3376    1. If a comment in an extended regex that started immediately after a meta-item
3377    extended to the end of string, PCRE compiled incorrect data. This could lead to
3378    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
3380    2. Moved to autoconf 2.53 and libtool 1.4.2.
3382    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
3383    the special perltest8 script is no longer needed - all the tests can be run
3384    from a single perltest script.
3386    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
3387    by \s. It has now been removed in PCRE. This means it isn't recognized as
3388    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
3389    class [:space:] *does* include VT, thereby creating a mess.
3391    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
3392    space and tab.
3394    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
3395    its new features into the main test script, reducing the number of scripts.
3397    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
3398    were backward compatible, and made the (?i) apply to the whole pattern, as if
3399    /i were given. Now it behaves more logically, and applies the option setting
3400    only to what follows. PCRE has been changed to follow suit. However, if it
3401    finds options settings right at the start of the pattern, it extracts them into
3402    the global options, as before. Thus, they show up in the info data.
3404    8. Added support for the \Q...\E escape sequence. Characters in between are
3405    treated as literals. This is slightly different from Perl in that $ and @ are
3406    also handled as literals inside the quotes. In Perl, they will cause variable
3407    interpolation. Note the following examples:
3409        Pattern            PCRE matches      Perl matches
3411        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
3412        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
3413        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
3415    For compatibility with Perl, \Q...\E sequences are recognized inside character
3416    classes as well as outside them.
3418    9. Re-organized 3 code statements in pcretest to avoid "overflow in
3419    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
3420    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
3421    signed/unsigned warnings.
3423    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
3424    option for pcretest, so I've replaced it by a simple function that does just
3425    that job.
3427    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
3428    "pcregrep -".
3430    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
3431    Java package. This provides some syntactic sugar for simple cases of what my
3432    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
3433    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
3434    item, you can use this simplified notation. Note that only makes sense with
3435    greedy quantifiers. Consequently, the use of the possessive quantifier forces
3436    greediness, whatever the setting of the PCRE_UNGREEDY option.
3438    13. A change of greediness default within a pattern was not taking effect at
3439    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
3440    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
3441    was abstracted outside.
3443    14. PCRE now supports the \G assertion. It is true when the current matching
3444    position is at the start point of the match. This differs from \A when the
3445    starting offset is non-zero. Used with the /g option of pcretest (or similar
3446    code), it works in the same way as it does for Perl's /g option. If all
3447    alternatives of a regex begin with \G, the expression is anchored to the start
3448    match position, and the "anchored" flag is set in the compiled expression.
3450    15. Some bugs concerning the handling of certain option changes within patterns
3451    have been fixed. These applied to options other than (?ims). For example,
3452    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
3453    been the other way round. Some of this was related to change 7 above.
3455    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
3456    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
3457    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
3458    POSIX classes only within a class (e.g. /[[:alpha:]]/).
3460    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
3461    mode. Unlike ".", it always matches newline, whatever the setting of
3462    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
3463    assertions. Perl allows it, but it doesn't (in general) work because it can't
3464    calculate the length of the lookbehind. At least, that's the case for Perl
3465    5.8.0 - I've been told they are going to document that it doesn't work in
3466    future.
3468    18. Added an error diagnosis for escapes that PCRE does not support: these are
3469    \L, \l, \N, \P, \p, \U, \u, and \X.
3471    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
3472    reading past the end of the pattern in cases such as /[abcd/.
3474    20. PCRE was getting more memory than necessary for patterns with classes that
3475    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
3477    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
3478    compiling PCRE for use with Virtual Pascal.
3480    22. Small fix to the Makefile to make it work properly if the build is done
3481    outside the source tree.
3483    23. Added a new extension: a condition to go with recursion. If a conditional
3484    subpattern starts with (?(R) the "true" branch is used if recursion has
3485    happened, whereas the "false" branch is used only at the top level.
3487    24. When there was a very long string of literal characters (over 255 bytes
3488    without UTF support, over 250 bytes with UTF support), the computation of how
3489    much memory was required could be incorrect, leading to segfaults or other
3490    strange effects.
3492    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
3493    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
3494    there was a subsequent back reference to those brackets. This meant that, for
3495    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
3496    possible to check for precisely this case. All we can do is abandon the
3497    optimization if .* occurs inside capturing brackets when there are any back
3498    references whatsoever. (See below for a better fix that came later.)
3500    26. The handling of the optimization for finding the first character of a
3501    non-anchored pattern, and for finding a character that is required later in the
3502    match were failing in some cases. This didn't break the matching; it just
3503    failed to optimize when it could. The way this is done has been re-implemented.
3505    27. Fixed typo in error message for invalid (?R item (it said "(?p").
3507    28. Added a new feature that provides some of the functionality that Perl
3508    provides with (?{...}). The facility is termed a "callout". The way it is done
3509    in PCRE is for the caller to provide an optional function, by setting
3510    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
3511    global variable. By default it is unset, which disables all calling out. To get
3512    the function called, the regex must include (?C) at appropriate points. This
3513    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
3514    This provides a means of identifying different callout points. When PCRE
3515    reaches such a point in the regex, if pcre_callout has been set, the external
3516    function is called. It is provided with data in a structure called
3517    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
3518    matching continues; if it returns a non-zero value, the match at the current
3519    point fails. However, backtracking will occur if possible. [This was changed
3520    later and other features added - see item 49 below.]
3522    29. pcretest is upgraded to test the callout functionality. It provides a
3523    callout function that displays information. By default, it shows the start of
3524    the match and the current position in the text. There are some new data escapes
3525    to vary what happens:
3527        \C+         in addition, show current contents of captured substrings
3528        \C-         do not supply a callout function
3529        \C!n        return 1 when callout number n is reached
3530        \C!n!m      return 1 when callout number n is reached for the mth time
3532    30. If pcregrep was called with the -l option and just a single file name, it
3533    output "<stdin>" if a match was found, instead of the file name.
3535    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
3536    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
3537    pcre_exec(). This saves a malloc/free per call. The default value of
3538    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
3539    when configuring.
3541    32. The default maximum size of a compiled pattern is 64K. There have been a
3542    few cases of people hitting this limit. The code now uses macros to handle the
3543    storing of links as offsets within the compiled pattern. It defaults to 2-byte
3544    links, but this can be changed to 3 or 4 bytes by --with-link-size when
3545    configuring. Tests 2 and 5 work only with 2-byte links because they output
3546    debugging information about compiled patterns.
3548    33. Internal code re-arrangements:
3550    (a) Moved the debugging function for printing out a compiled regex into
3551        its own source file (printint.c) and used #include to pull it into
3552        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
3553        separate copies.
3555    (b) Defined the list of op-code names for debugging as a macro in
3556        internal.h so that it is next to the definition of the opcodes.
3558    (c) Defined a table of op-code lengths for simpler skipping along compiled
3559        code. This is again a macro in internal.h so that it is next to the
3560        definition of the opcodes.
3562    34. Added support for recursive calls to individual subpatterns, along the
3563    lines of Robin Houston's patch (but implemented somewhat differently).
3565    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
3566    allow it to read and process whole directories in Win32. This code was
3567    contributed by Lionel Fourquaux; it has not been tested by me.
3569    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
3570    used to name a group. Names consist of alphanumerics and underscores, and must
3571    be unique. Back references use the syntax (?P=name) and recursive calls use
3572    (?P>name) which is a PCRE extension to the Python extension. Groups still have
3573    numbers. The function pcre_fullinfo() can be used after compilation to extract
3574    a name/number map. There are three relevant calls:
3576      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
3577      PCRE_INFO_NAMECOUNT            yields the number of entries
3578      PCRE_INFO_NAMETABLE            yields a pointer to the map.
3580    The map is a vector of fixed-size entries. The size of each entry depends on
3581    the length of the longest name used. The first two bytes of each entry are the
3582    group number, most significant byte first. There follows the corresponding
3583    name, zero terminated. The names are in alphabetical order.