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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.13 30-Apr-2011
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
9    2.  Two minor typos in pcre_internal.h have been fixed.
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
142    Version 8.12 15-Jan-2011
143    ------------------------
145    1.  Fixed some typos in the markup of the man pages, and wrote a script that
146        checks for such things as part of the documentation building process.
148    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
149        --match-limit and --recursion-limit options (added for 8.11). In
150        particular, this made one of the standard tests fail. (The integer value
151        went into the wrong half of a long int.)
153    3.  If the --colour option was given to pcregrep with -v (invert match), it
154        did strange things, either producing crazy output, or crashing. It should,
155        of course, ignore a request for colour when reporting lines that do not
156        match.
158    4.  Another pcregrep bug caused similar problems if --colour was specified with
159        -M (multiline) and the pattern match finished with a line ending.
161    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
162        matched in multiline mode, the following line was shown as part of the
163        match. This seems wrong, so I have changed it.
165    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
166        the check for further matches in the same line (so they could be coloured)
167        to overrun the end of the current line. If another match was found, it was
168        incorrectly shown (and then shown again when found in the next line).
170    7.  If pcregrep was compiled under Windows, there was a reference to the
171        function pcregrep_exit() before it was defined. I am assuming this was
172        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
173        reported by a user. I've moved the definition above the reference.
176    Version 8.11 10-Dec-2010
177    ------------------------
179    1.  (*THEN) was not working properly if there were untried alternatives prior
180        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
181        backtracked to try for "b" instead of moving to the next alternative branch
182        at the same level (in this case, to look for "c"). The Perl documentation
183        is clear that when (*THEN) is backtracked onto, it goes to the "next
184        alternative in the innermost enclosing group".
186    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
187        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
188        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
189        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
190        (*THEN).
192    3.  If \s appeared in a character class, it removed the VT character from
193        the class, even if it had been included by some previous item, for example
194        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
195        of \s, but is part of the POSIX "space" class.)
197    4.  A partial match never returns an empty string (because you can always
198        match an empty string at the end of the subject); however the checking for
199        an empty string was starting at the "start of match" point. This has been
200        changed to the "earliest inspected character" point, because the returned
201        data for a partial match starts at this character. This means that, for
202        example, /(?<=abc)def/ gives a partial match for the subject "abc"
203        (previously it gave "no match").
205    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
206        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
207        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
208        has an implication that the given string is incomplete (because a partial
209        match is preferred over a full match). For this reason, these items now
210        give a partial match in this situation. [Aside: previously, the one case
211        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
212        match rather than a full match, which was wrong by the old rules, but is
213        now correct.]
215    6.  There was a bug in the handling of #-introduced comments, recognized when
216        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
217        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
218        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
219        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
220        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
221        places in pcre_compile().
223    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
224        comments when looking ahead for named forward references to subpatterns,
225        the only newline sequence it recognized was NL. It now handles newlines
226        according to the set newline convention.
228    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
229        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
230        cater for a lack of strerror(). These oversights have been fixed.
232    9.  Added --match-limit and --recursion-limit to pcregrep.
234    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
236    11. When the -o option was used, pcregrep was setting a return code of 1, even
237        when matches were found, and --line-buffered was not being honoured.
239    12. Added an optional parentheses number to the -o and --only-matching options
240        of pcregrep.
242    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
243        can match an empty string. The code to do it in pcretest and pcredemo
244        needed fixing:
246        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
247            only one byte after an empty string match just before CRLF (this case
248            just got forgotten; "any" and "anycrlf" were OK).
250        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
251            mode when an empty string match preceded an ASCII character followed by
252            a non-ASCII character. (The code for advancing by one character rather
253            than one byte was nonsense.)
255        (c) The pcredemo.c sample program did not have any code at all to handle
256            the cases when CRLF is a valid newline sequence.
258    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
259        as a starting offset was within the subject string. There is now a new
260        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
261        negative or greater than the length of the string. In order to test this,
262        pcretest is extended to allow the setting of negative starting offsets.
264    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
265        starting offset points to the beginning of a UTF-8 character was
266        unnecessarily clumsy. I tidied it up.
268    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
269        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
271    17. Nobody had reported that the --include_dir option, which was added in
272        release 7.7 should have been called --include-dir (hyphen, not underscore)
273        for compatibility with GNU grep. I have changed it to --include-dir, but
274        left --include_dir as an undocumented synonym, and the same for
275        --exclude-dir, though that is not available in GNU grep, at least as of
276        release 2.5.4.
278    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
279        characters from a string of bytes) have been redefined so as not to use
280        loops, in order to improve performance in some environments. At the same
281        time, I abstracted some of the common code into auxiliary macros to save
282        repetition (this should not affect the compiled code).
284    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
285        compile-time error is now given if \c is not followed by an ASCII
286        character, that is, a byte less than 128. (In EBCDIC mode, the code is
287        different, and any byte value is allowed.)
289    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
290        START_OPTIMIZE option, which is now allowed at compile time - but just
291        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
292        to pcregrep and other applications that have no direct access to PCRE
293        options. The new /Y option in pcretest sets this option when calling
294        pcre_compile().
296    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
297        back references. Groups containing recursive back references were forced to
298        be atomic by that change, but in the case of named groups, the amount of
299        memory required was incorrectly computed, leading to "Failed: internal
300        error: code overflow". This has been fixed.
302    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
303        pcretest.c, to avoid build problems in some Borland environments.
306    Version 8.10 25-Jun-2010
307    ------------------------
309    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
310        THEN.
312    2.  (*ACCEPT) was not working when inside an atomic group.
314    3.  Inside a character class, \B is treated as a literal by default, but
315        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
316        causes the error). The code is unchanged, but I tidied the documentation.
318    4.  Inside a character class, PCRE always treated \R and \X as literals,
319        whereas Perl faults them if its -w option is set. I have changed PCRE so
320        that it faults them when PCRE_EXTRA is set.
322    5.  Added support for \N, which always matches any character other than
323        newline. (It is the same as "." when PCRE_DOTALL is not set.)
325    6.  When compiling pcregrep with newer versions of gcc which may have
326        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
327        declared with attribute warn_unused_result" were given. Just casting the
328        result to (void) does not stop the warnings; a more elaborate fudge is
329        needed. I've used a macro to implement this.
331    7.  Minor change to pcretest.c to avoid a compiler warning.
333    8.  Added four artifical Unicode properties to help with an option to make
334        \s etc use properties (see next item). The new properties are: Xan
335        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
337    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
338        use Unicode properties. (*UCP) at the start of a pattern can be used to set
339        this option. Modified pcretest to add /W to test this facility. Added
340        REG_UCP to make it available via the POSIX interface.
342    10. Added --line-buffered to pcregrep.
344    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
345        studied, and the match started with a letter with a code point greater than
346        127 whose first byte was different to the first byte of the other case of
347        the letter, the other case of this starting letter was not recognized
348        (#976).
350    12. If a pattern that was studied started with a repeated Unicode property
351        test, for example, \p{Nd}+, there was the theoretical possibility of
352        setting up an incorrect bitmap of starting bytes, but fortunately it could
353        not have actually happened in practice until change 8 above was made (it
354        added property types that matched character-matching opcodes).
356    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
357        possible starting bytes for non-anchored patterns.
359    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
360        \R, and also a number of cases that involve Unicode properties, both
361        explicit and implicit when PCRE_UCP is set.
363    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
364        input, it could crash or give wrong results if characters with values
365        greater than 0xc0 were present in the subject string. (Detail: it assumed
366        UTF-8 input when processing these items.)
368    16. Added a lot of (int) casts to avoid compiler warnings in systems where
369        size_t is 64-bit (#991).
371    17. Added a check for running out of memory when PCRE is compiled with
372        --disable-stack-for-recursion (#990).
374    18. If the last data line in a file for pcretest does not have a newline on
375        the end, a newline was missing in the output.
377    19. The default pcre_chartables.c file recognizes only ASCII characters (values
378        less than 128) in its various bitmaps. However, there is a facility for
379        generating tables according to the current locale when PCRE is compiled. It
380        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
381        characters, are recognized by isspace() and therefore were getting set in
382        these tables, and indeed these tables seem to approximate to ISO 8859. This
383        caused a problem in UTF-8 mode when pcre_study() was used to create a list
384        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
385        which of course cannot start UTF-8 characters. I have changed the code so
386        that only real ASCII characters (less than 128) and the correct starting
387        bytes for UTF-8 encodings are set for characters greater than 127 when in
388        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
389        altogether.)
391    20. Added the /T option to pcretest so as to be able to run tests with non-
392        standard character tables, thus making it possible to include the tests
393        used for 19 above in the standard set of tests.
395    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
396        reference to a subpattern the other side of a comment that contains an
397        opening parenthesis caused either an internal compiling error, or a
398        reference to the wrong subpattern.
401    Version 8.02 19-Mar-2010
402    ------------------------
404    1.  The Unicode data tables have been updated to Unicode 5.2.0.
406    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
407        configured.
409    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
410        original author of that file, following a query about its status.
412    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
413        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
415    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
416        quantifier applied to a forward-referencing subroutine call, could compile
417        incorrect code or give the error "internal error: previously-checked
418        referenced subpattern not found".
420    6.  Both MS Visual Studio and Symbian OS have problems with initializing
421        variables to point to external functions. For these systems, therefore,
422        pcre_malloc etc. are now initialized to local functions that call the
423        relevant global functions.
425    7.  There were two entries missing in the vectors called coptable and poptable
426        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
427        I've fixed the data, and added a kludgy way of testing at compile time that
428        the lengths are correct (equal to the number of opcodes).
430    8.  Following on from 7, I added a similar kludge to check the length of the
431        eint vector in pcreposix.c.
433    9.  Error texts for pcre_compile() are held as one long string to avoid too
434        much relocation at load time. To find a text, the string is searched,
435        counting zeros. There was no check for running off the end of the string,
436        which could happen if a new error number was added without updating the
437        string.
439    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
441    11. \K was not working if it appeared in an atomic group or in a group that
442        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
443        \K is "not well defined" if used in an assertion. PCRE now accepts it if
444        the assertion is positive, but not if it is negative.
446    12. Change 11 fortuitously reduced the size of the stack frame used in the
447        "match()" function of pcre_exec.c by one pointer. Forthcoming
448        implementation of support for (*MARK) will need an extra pointer on the
449        stack; I have reserved it now, so that the stack frame size does not
450        decrease.
452    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
453        item in branch that calls a recursion is a subroutine call - as in the
454        second branch in the above example - was incorrectly given the compile-
455        time error "recursive call could loop indefinitely" because pcre_compile()
456        was not correctly checking the subroutine for matching a non-empty string.
458    14. The checks for overrunning compiling workspace could trigger after an
459        overrun had occurred. This is a "should never occur" error, but it can be
460        triggered by pathological patterns such as hundreds of nested parentheses.
461        The checks now trigger 100 bytes before the end of the workspace.
463    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
466    Version 8.01 19-Jan-2010
467    ------------------------
469    1.  If a pattern contained a conditional subpattern with only one branch (in
470        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
471        computed the wrong minimum data length (which is of course zero for such
472        subpatterns). This could cause incorrect "no match" results.
474    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
475        the pattern is reset in the first branch, pcre_compile() failed with
476        "internal error: code overflow at offset...". This happened only when
477        the reset was to the original external option setting. (An optimization
478        abstracts leading options settings into an external setting, which was the
479        cause of this.)
481    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
482        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
483        assertion pattern did not match (meaning that the assertion was true), it
484        was incorrectly treated as false if the SKIP had been reached during the
485        matching. This also applied to assertions used as conditions.
487    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
488        assertion subpattern, including such a pattern used as a condition,
489        unpredictable results occurred, instead of the error return
492    5.  The C++ GlobalReplace function was not working like Perl for the special
493        situation when an empty string is matched. It now does the fancy magic
494        stuff that is necessary.
496    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
497        removed. (These were left over from very, very early versions of PCRE.)
499    7.  Some cosmetic changes to the code to make life easier when compiling it
500        as part of something else:
502        (a) Change DEBUG to PCRE_DEBUG.
504        (b) In pcre_compile(), rename the member of the "branch_chain" structure
505            called "current" as "current_branch", to prevent a collision with the
506            Linux macro when compiled as a kernel module.
508        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
509            prevent a collision with the Linux macro when compiled as a kernel
510            module.
512    8.  In pcre_compile() there are some checks for integer overflows that used to
513        cast potentially large values to (double). This has been changed to that
514        when building, a check for int64_t is made, and if it is found, it is used
515        instead, thus avoiding the use of floating point arithmetic. (There is no
516        other use of FP in PCRE.) If int64_t is not found, the fallback is to
517        double.
519    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
520        2005 (difference between two addresses compared to an unsigned value).
522    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
523        custom one, because of the following reported problem in Windows:
525          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
526              under Win32.
527          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
528              therefore missing the function definition.
529          - The compiler thus generates a "C" signature for the test function.
530          - The linker fails to find the "C" function.
531          - PCRE fails to configure if asked to do so against libbz2.
533    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
534        messages were output:
536          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
537          rerunning libtoolize, to keep the correct libtool macros in-tree.
538          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
540        I have done both of these things.
542    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
543        most of the time, it *can* run out if it is given a pattern that contains a
544        runaway infinite recursion. I updated the discussion in the pcrestack man
545        page.
547    13. Now that we have gone to the x.xx style of version numbers, the minor
548        version may start with zero. Using 08 or 09 is a bad idea because users
549        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
550        interpreted as invalid octal numbers. I've updated the previous comment in
551        configure.ac, and also added a check that gives an error if 08 or 09 are
552        used.
554    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
555        causing partial matching to fail when the end of the subject matched \W
556        in a UTF-8 pattern where \W was quantified with a minimum of 3.
558    15. There were some discrepancies between the declarations in pcre_internal.h
559        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
560        their definitions. The declarations used "const uschar *" and the
561        definitions used USPTR. Even though USPTR is normally defined as "const
562        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
563        reported that: "This difference in casting confuses some C++ compilers, for
564        example, SunCC recognizes above declarations as different functions and
565        generates broken code for hbpcre." I have changed the declarations to use
566        USPTR.
568    16. GNU libtool is named differently on some systems. The autogen.sh script now
569        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
570        (FreeBSD).
572    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
573        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
574        comment: "Figure out how to create a longlong from a string: strtoll and
575        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
576        instance, but it only takes 2 args instead of 3!"
578    18. A subtle bug concerned with back references has been fixed by a change of
579        specification, with a corresponding code fix. A pattern such as
580        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
581        refers, was giving matches when it shouldn't. For example, xa=xaaa would
582        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
583        same bug. Such groups have to be quantified to be useful, or contained
584        inside another quantified group. (If there's no repetition, the reference
585        can never match.) The problem arises because, having left the group and
586        moved on to the rest of the pattern, a later failure that backtracks into
587        the group uses the captured value from the final iteration of the group
588        rather than the correct earlier one. I have fixed this in PCRE by forcing
589        any group that contains a reference to itself to be an atomic group; that
590        is, there cannot be any backtracking into it once it has completed. This is
591        similar to recursive and subroutine calls.
594    Version 8.00 19-Oct-09
595    ----------------------
597    1.  The table for translating pcre_compile() error codes into POSIX error codes
598        was out-of-date, and there was no check on the pcre_compile() error code
599        being within the table. This could lead to an OK return being given in
600        error.
602    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
603        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
604        in a Windows environment.
606    3.  The pcregrep --count option prints the count for each file even when it is
607        zero, as does GNU grep. However, pcregrep was also printing all files when
608        --files-with-matches was added. Now, when both options are given, it prints
609        counts only for those files that have at least one match. (GNU grep just
610        prints the file name in this circumstance, but including the count seems
611        more useful - otherwise, why use --count?) Also ensured that the
612        combination -clh just lists non-zero counts, with no names.
614    4.  The long form of the pcregrep -F option was incorrectly implemented as
615        --fixed_strings instead of --fixed-strings. This is an incompatible change,
616        but it seems right to fix it, and I didn't think it was worth preserving
617        the old behaviour.
619    5.  The command line items --regex=pattern and --regexp=pattern were not
620        recognized by pcregrep, which required --regex pattern or --regexp pattern
621        (with a space rather than an '='). The man page documented the '=' forms,
622        which are compatible with GNU grep; these now work.
624    6.  No libpcreposix.pc file was created for pkg-config; there was just
625        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
627    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
628        when UCP support is not needed, by modifying the Python script that
629        generates it from Unicode data files. This should not matter if the module
630        is correctly used as a library, but I received one complaint about 50K of
631        unwanted data. My guess is that the person linked everything into his
632        program rather than using a library. Anyway, it does no harm.
634    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
635        was a minimum greater than 1 for a wide character in a possessive
636        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
637        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
638        character. Chaos in the form of incorrect output or a compiling loop could
639        result.
641    9.  The restrictions on what a pattern can contain when partial matching is
642        requested for pcre_exec() have been removed. All patterns can now be
643        partially matched by this function. In addition, if there are at least two
644        slots in the offset vector, the offset of the earliest inspected character
645        for the match and the offset of the end of the subject are set in them when
646        PCRE_ERROR_PARTIAL is returned.
648    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
649        synonymous with PCRE_PARTIAL, for backwards compatibility, and
650        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
651        and may be more useful for multi-segment matching.
653    11. Partial matching with pcre_exec() is now more intuitive. A partial match
654        used to be given if ever the end of the subject was reached; now it is
655        given only if matching could not proceed because another character was
656        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
657        string "Z", which now yields "no match" instead of "partial match". In the
658        case of pcre_dfa_exec(), "no match" is given if every matching path for the
659        final character ended with (*FAIL).
661    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
662        if the pattern had a "must contain" character that was already found in the
663        earlier partial match, unless partial matching was again requested. For
664        example, with the pattern /dog.(body)?/, the "must contain" character is
665        "g". If the first part-match was for the string "dog", restarting with
666        "sbody" failed. This bug has been fixed.
668    13. The string returned by pcre_dfa_exec() after a partial match has been
669        changed so that it starts at the first inspected character rather than the
670        first character of the match. This makes a difference only if the pattern
671        starts with a lookbehind assertion or \b or \B (\K is not supported by
672        pcre_dfa_exec()). It's an incompatible change, but it makes the two
673        matching functions compatible, and I think it's the right thing to do.
675    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
676        so that the demonstration program is easily available in environments where
677        PCRE has not been installed from source.
679    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
680        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
681        library.
683    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
684        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
685        is not the first non-POSIX option to be added. Clearly some people find
686        these options useful.
688    17. If a caller to the POSIX matching function regexec() passes a non-zero
689        value for nmatch with a NULL value for pmatch, the value of
690        nmatch is forced to zero.
692    18. RunGrepTest did not have a test for the availability of the -u option of
693        the diff command, as RunTest does. It now checks in the same way as
694        RunTest, and also checks for the -b option.
696    19. If an odd number of negated classes containing just a single character
697        interposed, within parentheses, between a forward reference to a named
698        subpattern and the definition of the subpattern, compilation crashed with
699        an internal error, complaining that it could not find the referenced
700        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
701        [The bug was that it was starting one character too far in when skipping
702        over the character class, thus treating the ] as data rather than
703        terminating the class. This meant it could skip too much.]
705    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
706        /g option in pcretest when the pattern contains \K, which makes it possible
707        to have an empty string match not at the start, even when the pattern is
708        anchored. Updated pcretest and pcredemo to use this option.
710    21. If the maximum number of capturing subpatterns in a recursion was greater
711        than the maximum at the outer level, the higher number was returned, but
712        with unset values at the outer level. The correct (outer level) value is
713        now given.
715    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
716        PCRE did not set those parentheses (unlike Perl). I have now found a way to
717        make it do so. The string so far is captured, making this feature
718        compatible with Perl.
720    23. The tests have been re-organized, adding tests 11 and 12, to make it
721        possible to check the Perl 5.10 features against Perl 5.10.
723    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
724        pattern matches a fixed length string. PCRE did not allow this; now it
725        does. Neither allows recursion.
727    25. I finally figured out how to implement a request to provide the minimum
728        length of subject string that was needed in order to match a given pattern.
729        (It was back references and recursion that I had previously got hung up
730        on.) This code has now been added to pcre_study(); it finds a lower bound
731        to the length of subject needed. It is not necessarily the greatest lower
732        bound, but using it to avoid searching strings that are too short does give
733        some useful speed-ups. The value is available to calling programs via
734        pcre_fullinfo().
736    26. While implementing 25, I discovered to my embarrassment that pcretest had
737        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
738        study optimizations had never been tested with that matching function.
739        Oops. What is worse, even when it was passed study data, there was a bug in
740        pcre_dfa_exec() that meant it never actually used it. Double oops. There
741        were also very few tests of studied patterns with pcre_dfa_exec().
743    27. If (?| is used to create subpatterns with duplicate numbers, they are now
744        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
745        on the other side of the coin, they are no longer allowed to have different
746        names, because these cannot be distinguished in PCRE, and this has caused
747        confusion. (This is a difference from Perl.)
749    28. When duplicate subpattern names are present (necessarily with different
750        numbers, as required by 27 above), and a test is made by name in a
751        conditional pattern, either for a subpattern having been matched, or for
752        recursion in such a pattern, all the associated numbered subpatterns are
753        tested, and the overall condition is true if the condition is true for any
754        one of them. This is the way Perl works, and is also more like the way
755        testing by number works.
758    Version 7.9 11-Apr-09
759    ---------------------
761    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
762        (pcretest), all targets were linked against these libraries. This included
763        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
764        libraries. This caused unwanted dependencies to be created. This problem
765        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
766        pcretest is linked with readline.
768    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
769        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
770        moved outside it again, because FALSE and TRUE are already defined in AIX,
771        but BOOL is not.
773    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
774        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
776    4.  The pcregrep documentation said spaces were inserted as well as colons (or
777        hyphens) following file names and line numbers when outputting matching
778        lines. This is not true; no spaces are inserted. I have also clarified the
779        wording for the --colour (or --color) option.
781    5.  In pcregrep, when --colour was used with -o, the list of matching strings
782        was not coloured; this is different to GNU grep, so I have changed it to be
783        the same.
785    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
786        each matching line was coloured. Now it goes on to look for further matches
787        of any of the test patterns, which is the same behaviour as GNU grep.
789    7.  A pattern that could match an empty string could cause pcregrep to loop; it
790        doesn't make sense to accept an empty string match in pcregrep, so I have
791        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
792        seems to be how GNU grep behaves.
794    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
795        start or after a newline", because the conditional assertion was not being
796        correctly handled. The rule now is that both the assertion and what follows
797        in the first alternative must satisfy the test.
799    9.  If auto-callout was enabled in a pattern with a conditional group whose
800        condition was an assertion, PCRE could crash during matching, both with
801        pcre_exec() and pcre_dfa_exec().
803    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
804        used for matching.
806    11. Unicode property support in character classes was not working for
807        characters (bytes) greater than 127 when not in UTF-8 mode.
809    12. Added the -M command line option to pcretest.
811    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
813    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
815    16. Added comments and documentation about mis-use of no_arg in the C++
816        wrapper.
818    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
819        from Martin Jerabek that uses macro names for all relevant character and
820        string constants.
822    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
823        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
824        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
825        these, but not everybody uses configure.
827    19. A conditional group that had only one branch was not being correctly
828        recognized as an item that could match an empty string. This meant that an
829        enclosing group might also not be so recognized, causing infinite looping
830        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
831        with the subject "ab", where knowledge that the repeated group can match
832        nothing is needed in order to break the loop.
834    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
835        exec(), but without supplying a callout function, matching went wrong.
837    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
838        leak if the size of the offset vector was greater than 30. When the vector
839        is smaller, the saved offsets during recursion go onto a local stack
840        vector, but for larger vectors malloc() is used. It was failing to free
841        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
842        error, in fact).
844    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
845        heapframe that is used only when UTF-8 support is enabled. This caused no
846        problem, but was untidy.
848    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
849        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
850        included within another project.
852    24. Steven Van Ingelgem's patches to add more options to the CMake support,
853        slightly modified by me:
855          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
856              not building pcregrep.
858          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
859              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
861    25. Forward references, both numeric and by name, in patterns that made use of
862        duplicate group numbers, could behave incorrectly or give incorrect errors,
863        because when scanning forward to find the reference group, PCRE was not
864        taking into account the duplicate group numbers. A pattern such as
865        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
867    26. Changed a few more instances of "const unsigned char *" to USPTR, making
868        the feature of a custom pointer more persuasive (as requested by a user).
870    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
871        pcretest.c, inside #ifndefs, because it seems they are sometimes already
872        pre-defined.
874    28. Added support for (*UTF8) at the start of a pattern.
876    29. Arrange for flags added by the "release type" setting in CMake to be shown
877        in the configuration summary.
880    Version 7.8 05-Sep-08
881    ---------------------
883    1.  Replaced UCP searching code with optimized version as implemented for Ad
884        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
885        stage table and inline lookup instead of a function, giving speed ups of 2
886        to 5 times on some simple patterns that I tested. Permission was given to
887        distribute the MultiStage2.py script that generates the tables (it's not in
888        the tarball, but is in the Subversion repository).
890    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
891        scripts.
893    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
894        a group with a zero qualifier. The result of the study could be incorrect,
895        or the function might crash, depending on the pattern.
897    4.  Caseless matching was not working for non-ASCII characters in back
898        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
899        It now works when Unicode Property Support is available.
901    5.  In pcretest, an escape such as \x{de} in the data was always generating
902        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
903        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
904        truncation.
906    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
908    7.  Added two (int) casts to pcregrep when printing the difference of two
909        pointers, in case they are 64-bit values.
911    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
912        test 2 if it fails.
914    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
915        and a #define of that name to empty if it is not externally set. This is to
916        allow users of MSVC to set it if necessary.
918    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
919        the convenience functions in the pcre_get.c source file.
921    11. An option change at the start of a pattern that had top-level alternatives
922        could cause overwriting and/or a crash. This command provoked a crash in
923        some environments:
925          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
927        This potential security problem was recorded as CVE-2008-2371.
929    12. For a pattern where the match had to start at the beginning or immediately
930        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
931        pcre_dfa_exec() could read past the end of the passed subject if there was
932        no match. To help with detecting such bugs (e.g. with valgrind), I modified
933        pcretest so that it places the subject at the end of its malloc-ed buffer.
935    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
936        exec() might read past the end of the data buffer in UTF-8 mode.
938    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
939        the data contained the byte 0x85 as part of a UTF-8 character within its
940        first line. This applied both to normal and DFA matching.
942    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
943        /^[^d]*?$/8 failed to match "abc".
945    16. Added a missing copyright notice to pcrecpp_internal.h.
947    17. Make it more clear in the documentation that values returned from
948        pcre_exec() in ovector are byte offsets, not character counts.
950    18. Tidied a few places to stop certain compilers from issuing warnings.
952    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
953        supplied by Stefan Weber. I made a further small update for 7.8 because
954        there is a change of source arrangements: the pcre_searchfuncs.c module is
955        replaced by pcre_ucd.c.
958    Version 7.7 07-May-08
959    ---------------------
961    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
962        a string to a long long, pretend we don't even have a long long." This is
963        done by checking for the strtoq, strtoll, and _strtoi64 functions.
965    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
966        pre-7.6 versions, which defined a global no_arg variable instead of putting
967        it in the RE class. (See also #8 below.)
969    3.  Remove a line of dead code, identified by coverity and reported by Nuno
970        Lopes.
972    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
974        (1) The include/exclude patterns were being applied to the whole pathnames
975            of files, instead of just to the final components.
977        (2) If there was more than one level of directory, the subdirectories were
978            skipped unless they satisfied the include/exclude conditions. This is
979            inconsistent with GNU grep (and could even be seen as contrary to the
980            pcregrep specification - which I improved to make it absolutely clear).
981            The action now is always to scan all levels of directory, and just
982            apply the include/exclude patterns to regular files.
984    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
985        --exclude_dir in the tests to avoid scanning .svn directories.
987    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
988        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
989        doesn't support NULs in patterns.
991    7.  Added some missing "const"s to declarations of static tables in
992        pcre_compile.c and pcre_dfa_exec.c.
994    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
995        caused by fix #2  above. (Subsequently also a second patch to fix the
996        first patch. And a third patch - this was a messy problem.)
998    9.  Applied Craig's patch to remove the use of push_back().
1000    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
1001        matching function regexec().
1003    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
1004        which, however, unlike Perl's \g{...}, are subroutine calls, not back
1005        references. PCRE supports relative numbers with this syntax (I don't think
1006        Oniguruma does).
1008    12. Previously, a group with a zero repeat such as (...){0} was completely
1009        omitted from the compiled regex. However, this means that if the group
1010        was called as a subroutine from elsewhere in the pattern, things went wrong
1011        (an internal error was given). Such groups are now left in the compiled
1012        pattern, with a new opcode that causes them to be skipped at execution
1013        time.
1015    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
1016        to the way PCRE behaves:
1018        (a) A lone ] character is dis-allowed (Perl treats it as data).
1020        (b) A back reference to an unmatched subpattern matches an empty string
1021            (Perl fails the current match path).
1023        (c) A data ] in a character class must be notated as \] because if the
1024            first data character in a class is ], it defines an empty class. (In
1025            Perl it is not possible to have an empty class.) The empty class []
1026            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
1027            The negative empty class [^] matches any one character, independently
1028            of the DOTALL setting.
1030    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
1031        non-existent subpattern following a character class starting with ']' and
1032        containing () gave an internal compiling error instead of "reference to
1033        non-existent subpattern". Fortunately, when the pattern did exist, the
1034        compiled code was correct. (When scanning forwards to check for the
1035        existencd of the subpattern, it was treating the data ']' as terminating
1036        the class, so got the count wrong. When actually compiling, the reference
1037        was subsequently set up correctly.)
1039    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
1040        it was being rejected as not supported by pcre_dfa_exec(), even though
1041        other assertions are supported. I have made pcre_dfa_exec() support
1042        (*FAIL).
1044    16. The implementation of 13c above involved the invention of a new opcode,
1045        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
1046        cannot be changed at match time, I realized I could make a small
1047        improvement to matching performance by compiling OP_ALLANY instead of
1048        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
1049        on the OP_ANY path.
1051    17. Compiling pcretest on Windows with readline support failed without the
1052        following two fixes: (1) Make the unistd.h include conditional on
1053        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
1055    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1056        ncurses library to be included for pcretest when ReadLine support is
1057        requested, but also to allow for it to be overridden. This patch came from
1058        Daniel Bergström.
1060    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1061        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1062        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1063        spotting this.
1066    Version 7.6 28-Jan-08
1067    ---------------------
1069    1.  A character class containing a very large number of characters with
1070        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1071        overflow.
1073    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1074        HAVE_LONG_LONG is not defined.
1076    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1077        bring them up to date and include new features. This patch includes:
1079        - Fixed PH's badly added libz and libbz2 support.
1080        - Fixed a problem with static linking.
1081        - Added pcredemo. [But later removed - see 7 below.]
1082        - Fixed dftables problem and added an option.
1083        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1084            HAVE_LONG_LONG.
1085        - Added readline support for pcretest.
1086        - Added an listing of the option settings after cmake has run.
1088    4.  A user submitted a patch to Makefile that makes it easy to create
1089        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1090        Makefile.am that cause it to include this special target, without
1091        affecting anything else. Note that the same mingw target plus all
1092        the other distribution libraries and programs are now supported
1093        when configuring with CMake (see 6 below) instead of with
1094        Configure/Make.
1096    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1097        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1098        exported in the Windows port". It has not yet been confirmed that the patch
1099        solves the problem, but it does no harm.
1101    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1102        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1103        with CMake, and also correct the comment about stack recursion.
1105    7.  Remove the automatic building of pcredemo from the ./configure system and
1106        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1107        of a program that users should build themselves after PCRE is installed, so
1108        building it automatically is not really right. What is more, it gave
1109        trouble in some build environments.
1111    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1114    Version 7.5 10-Jan-08
1115    ---------------------
1117    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1118        values in parens when parsing an RE using the C++ wrapper."
1120    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1121        Characters greater than 255 were excluded from the class instead of being
1122        included.
1124    3.  The same bug as (2) above applied to negated POSIX classes such as
1125        [:^space:].
1127    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1128        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1129        I have changed it.
1131    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1132        first named subpattern) and a construct such as (?&a) would reference the
1133        first named subpattern whose name started with "a" (in other words, the
1134        length check was missing). Both these problems are fixed. "Subpattern name
1135        expected" is now given for (?&) (a zero-length name), and this patch also
1136        makes it give the same error for \k'' (previously it complained that that
1137        was a reference to a non-existent subpattern).
1139    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1140        this is right because (?- can be followed by option settings as well as by
1141        digits. I have, however, made the messages clearer.
1143    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1144        than the number used in the conditional) now cause a compile-time error.
1145        This is actually not compatible with Perl, which accepts such patterns, but
1146        treats the conditional as always being FALSE (as PCRE used to), but it
1147        seems to me that giving a diagnostic is better.
1149    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1150        and messages.
1152    9.  Fix two occurrences of "backslash" in comments that should have been
1153        "backspace".
1155    10. Remove two redundant lines of code that can never be obeyed (their function
1156        was moved elsewhere).
1158    11. The program that makes PCRE's Unicode character property table had a bug
1159        which caused it to generate incorrect table entries for sequences of
1160        characters that have the same character type, but are in different scripts.
1161        It amalgamated them into a single range, with the script of the first of
1162        them. In other words, some characters were in the wrong script. There were
1163        thirteen such cases, affecting characters in the following ranges:
1165          U+002b0 - U+002c1
1166          U+0060c - U+0060d
1167          U+0061e - U+00612
1168          U+0064b - U+0065e
1169          U+0074d - U+0076d
1170          U+01800 - U+01805
1171          U+01d00 - U+01d77
1172          U+01d9b - U+01dbf
1173          U+0200b - U+0200f
1174          U+030fc - U+030fe
1175          U+03260 - U+0327f
1176          U+0fb46 - U+0fbb1
1177          U+10450 - U+1049d
1179    12. The -o option (show only the matching part of a line) for pcregrep was not
1180        compatible with GNU grep in that, if there was more than one match in a
1181        line, it showed only the first of them. It now behaves in the same way as
1182        GNU grep.
1184    13. If the -o and -v options were combined for pcregrep, it printed a blank
1185        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1186        does the same. The return code can be used to tell if there were any
1187        non-matching lines.
1189    14. Added --file-offsets and --line-offsets to pcregrep.
1191    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1192        infinitely looping recursion. The bug was that positive lookaheads were not
1193        being skipped when checking for a possible empty match (negative lookaheads
1194        and both kinds of lookbehind were skipped).
1196    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1197        inclusion of <windows.h> to before rather than after the definition of
1198        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1200    17. Specifying a possessive quantifier with a specific limit for a Unicode
1201        character property caused pcre_compile() to compile bad code, which led at
1202        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1203        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1204        caused the error; without that there was no problem.
1206    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1208    19. Added --enable-pcretest-libreadline.
1210    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1211        RE::GlobalReplace(). As a result, the number of replacements returned was
1212        double what it should be. I removed one of the increments, but Craig sent a
1213        later patch that removed the other one (the right fix) and added unit tests
1214        that check the return values (which was not done before).
1216    21. Several CMake things:
1218        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1219            the names libpcre and libpcreposix, not just pcre and pcreposix.
1221        (2) The above change means that pcretest and pcregrep are now correctly
1222            linked with the newly-built libraries, not previously installed ones.
1226    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1227        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1228        UTF-8 newline character). The key issue is that the pattern starts .*;
1229        this means that the match must be either at the beginning, or after a
1230        newline. The bug was in the code for advancing after a failed match and
1231        checking that the new position followed a newline. It was not taking
1232        account of UTF-8 characters correctly.
1234    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1235        character classes. PCRE was not treating the sequence [:...:] as a
1236        character class unless the ... were all letters. Perl, however, seems to
1237        allow any characters between [: and :], though of course it rejects as
1238        unknown any "names" that contain non-letters, because all the known class
1239        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1240        for example, whereas PCRE did not - it did not recognize a POSIX character
1241        class. This seemed a bit dangerous, so the code has been changed to be
1242        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1243        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1244        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1245        Perl does, and where it didn't before.
1247    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1248        Windows environments %n is disabled by default.
1251    Version 7.4 21-Sep-07
1252    ---------------------
1254    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1255        means that a class such as [\s] counted as "explicit reference to CR or
1256        LF". That isn't really right - the whole point of the change was to try to
1257        help when there was an actual mention of one of the two characters. So now
1258        the change happens only if \r or \n (or a literal CR or LF) character is
1259        encountered.
1261    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1262        of both had grown to the point where there were only 3 bits left.
1263        Fortunately, there was spare space in the data structure, and so I have
1264        moved the internal flags into a new 16-bit field to free up more option
1265        bits.
1267    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1268        but did not set the internal JCHANGED flag - either of these is enough to
1269        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1270        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1271        start sets both bits.
1273    4.  Added options (at build time, compile time, exec time) to change \R from
1274        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1276    5.  doc/pcresyntax.html was missing from the distribution.
1278    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1279        compatibility, even though it is no longer used.
1281    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1282        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1283        windows.h file is present (where different names are used). [This was
1284        reversed later after testing - see 16 below.]
1286    8.  Changed all #include <config.h> to #include "config.h". There were also
1287        some further <pcre.h> cases that I changed to "pcre.h".
1289    9.  When pcregrep was used with the --colour option, it missed the line ending
1290        sequence off the lines that it output.
1292    10. It was pointed out to me that arrays of string pointers cause lots of
1293        relocations when a shared library is dynamically loaded. A technique of
1294        using a single long string with a table of offsets can drastically reduce
1295        these. I have refactored PCRE in four places to do this. The result is
1296        dramatic:
1298          Originally:                          290
1299          After changing UCP table:            187
1300          After changing error message table:   43
1301          After changing table of "verbs"       36
1302          After changing table of Posix names   22
1304        Thanks to the folks working on Gregex for glib for this insight.
1306    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1307        unicode-properties was also set.
1309    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1311    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1312        checked only for CRLF.
1314    14. Added casts to pcretest.c to avoid compiler warnings.
1316    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1318    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1319        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1320        entirely. This removes changes made in 7 above.
1322    17. The CMake files have been updated, and there is now more information about
1323        building with CMake in the NON-UNIX-USE document.
1326    Version 7.3 28-Aug-07
1327    ---------------------
1329     1. In the rejigging of the build system that eventually resulted in 7.1, the
1330        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1331        brackets there is not right, since it causes compilers to look for an
1332        installed pcre.h, not the version that is in the source that is being
1333        compiled (which of course may be different). I have changed it back to:
1335          #include "pcre.h"
1337        I have a vague recollection that the change was concerned with compiling in
1338        different directories, but in the new build system, that is taken care of
1339        by the VPATH setting the Makefile.
1341     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1342        when the subject happened to end in the byte 0x85 (e.g. if the last
1343        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1344        characters but of course it shouldn't be taken as a newline when it is part
1345        of another character. The bug was that, for an unlimited repeat of . in
1346        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1347        characters when looking for a newline.
1349     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1351     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1352        in debug output.
1354     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1355        long printing in the pcrecpp unittest when running under MinGW.
1357     6. ESC_K was left out of the EBCDIC table.
1359     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1360        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1361        limit also applies to "virtual nesting" when a pattern is recursive, and in
1362        this case 1000 isn't so big. I have been able to remove this limit at the
1363        expense of backing off one optimization in certain circumstances. Normally,
1364        when pcre_exec() would call its internal match() function recursively and
1365        immediately return the result unconditionally, it uses a "tail recursion"
1366        feature to save stack. However, when a subpattern that can match an empty
1367        string has an unlimited repetition quantifier, it no longer makes this
1368        optimization. That gives it a stack frame in which to save the data for
1369        checking that an empty string has been matched. Previously this was taken
1370        from the 1000-entry workspace that had been reserved. So now there is no
1371        explicit limit, but more stack is used.
1373     8. Applied Daniel's patches to solve problems with the import/export magic
1374        syntax that is required for Windows, and which was going wrong for the
1375        pcreposix and pcrecpp parts of the library. These were overlooked when this
1376        problem was solved for the main library.
1378     9. There were some crude static tests to avoid integer overflow when computing
1379        the size of patterns that contain repeated groups with explicit upper
1380        limits. As the maximum quantifier is 65535, the maximum group length was
1381        set at 30,000 so that the product of these two numbers did not overflow a
1382        32-bit integer. However, it turns out that people want to use groups that
1383        are longer than 30,000 bytes (though not repeat them that many times).
1384        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1385        made it possible to implement the integer overflow checks in a much more
1386        dynamic way, which I have now done. The artificial limitation on group
1387        length has been removed - we now have only the limit on the total length of
1388        the compiled pattern, which depends on the LINK_SIZE setting.
1390    10. Fixed a bug in the documentation for get/copy named substring when
1391        duplicate names are permitted. If none of the named substrings are set, the
1392        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1393        empty string.
1395    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1396        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1397        because the ] is interpreted as the first data character and the
1398        terminating ] is not found. PCRE has been made compatible with Perl in this
1399        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1400        cause memory overwriting.
1402    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1403        string has been matched (to stop an infinite loop). It was not recognizing
1404        a conditional subpattern that could match an empty string if that
1405        subpattern was within another subpattern. For example, it looped when
1406        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1407        condition was not nested. This bug has been fixed.
1409    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1410        past the start of the subject in the presence of bytes with the top bit
1411        set, for example "\x8aBCD".
1413    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1414        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1416    14. Optimized (?!) to (*FAIL).
1418    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1419        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1420        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1421        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1422        does: it's just the validity check that is more restrictive.
1424    16. Inserted checks for integer overflows during escape sequence (backslash)
1425        processing, and also fixed erroneous offset values for syntax errors during
1426        backslash processing.
1428    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1429        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1431    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1432        caused an overrun.
1434    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1435        something other than just ASCII characters) inside a group that had an
1436        unlimited repeat caused a loop at compile time (while checking to see
1437        whether the group could match an empty string).
1439    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1440        [\P{Any}] did so. (Error in the code for printing property names.)
1442    21. An orphan \E inside a character class could cause a crash.
1444    22. A repeated capturing bracket such as (A)? could cause a wild memory
1445        reference during compilation.
1447    23. There are several functions in pcre_compile() that scan along a compiled
1448        expression for various reasons (e.g. to see if it's fixed length for look
1449        behind). There were bugs in these functions when a repeated \p or \P was
1450        present in the pattern. These operators have additional parameters compared
1451        with \d, etc, and these were not being taken into account when moving along
1452        the compiled data. Specifically:
1454        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1455            length.
1457        (b) An item such as \pL+ within a repeated group could cause crashes or
1458            loops.
1460        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1461            "reference to non-existent subpattern" error.
1463        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1465    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1466        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1468    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1470    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1471        character were causing crashes (broken optimization).
1473    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1474        \p or \P) caused a compile-time loop.
1476    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1477        break. For example, the unstudied pattern [\r\n]A does not match the string
1478        "\r\nA" because change 7.0/46 below moves the current point on by two
1479        characters after failing to match at the start. However, the pattern \nA
1480        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1481        the same is true. There doesn't seem any very clean way out of this, but
1482        what I have chosen to do makes the common cases work: PCRE now takes note
1483        of whether there can be an explicit match for \r or \n anywhere in the
1484        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1485        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1486        pattern has explicit CR or LF references.
1488    29. Added (*CR) etc for changing newline setting at start of pattern.
1491    Version 7.2 19-Jun-07
1492    ---------------------
1494     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1495        which is apparently normally available under Windows.
1497     2. Re-jig the pcregrep tests with different newline settings in an attempt
1498        to make them independent of the local environment's newline setting.
1500     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1502     4. Some of the "internals" tests were previously cut out when the link size
1503        was not 2, because the output contained actual offsets. The recent new
1504        "Z" feature of pcretest means that these can be cut out, making the tests
1505        usable with all link sizes.
1507     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1508        stack recursion. This gives a massive performance boost under BSD, but just
1509        a small improvement under Linux. However, it saves one field in the frame
1510        in all cases.
1512     6. Added more features from the forthcoming Perl 5.10:
1514        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1515            recursion call. It refers to the nth most recently opened parentheses.
1517        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1518            to be opened parentheses.
1520        (c) Conditions that refer to capturing parentheses can be specified
1521            relatively, for example, (?(-2)... or (?(+3)...
1523        (d) \K resets the start of the current match so that everything before
1524            is not part of it.
1526        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1528        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1529            reference syntax.
1531        (g) (?| introduces a group in which the numbering of parentheses in each
1532            alternative starts with the same number.
1534        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1536     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1539     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1540        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1541        for detecting groups that can match an empty string.
1543     9. A pattern with a very large number of alternatives (more than several
1544        hundred) was running out of internal workspace during the pre-compile
1545        phase, where pcre_compile() figures out how much memory will be needed. A
1546        bit of new cunning has reduced the workspace needed for groups with
1547        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1548        workspace instead of running out of the 4096 that are available.
1550    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1552    11. Applied patch from Google to remove an optimization that didn't quite work.
1553        The report of the bug said:
1555          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1556          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1557          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1559    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1560        it matched the wrong number of bytes.
1563    Version 7.1 24-Apr-07
1564    ---------------------
1566     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1567        that is more "standard", making use of automake and other Autotools. There
1568        is some re-arrangement of the files and adjustment of comments consequent
1569        on this.
1571     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1572        for recursive directory scanning broke on some systems because the files
1573        are not scanned in any specific order and on different systems the order
1574        was different. A call to "sort" has been inserted into RunGrepTest for the
1575        approprate test as a short-term fix. In the longer term there may be an
1576        alternative.
1578     3. I had an email from Eric Raymond about problems translating some of PCRE's
1579        man pages to HTML (despite the fact that I distribute HTML pages, some
1580        people do their own conversions for various reasons). The problems
1581        concerned the use of low-level troff macros .br and .in. I have therefore
1582        removed all such uses from the man pages (some were redundant, some could
1583        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1584        HTML has been updated to handle .nf/.fi and to complain if it encounters
1585        .br or .in.
1587     4. Updated comments in configure.ac that get placed in config.h.in and also
1588        arranged for config.h to be included in the distribution, with the name
1589        config.h.generic, for the benefit of those who have to compile without
1590        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1592     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1593        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1594        makevp.bat for the current PCRE, using the additional files
1595        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1597     6. A Windows user reported a minor discrepancy with test 2, which turned out
1598        to be caused by a trailing space on an input line that had got lost in his
1599        copy. The trailing space was an accident, so I've just removed it.
1601     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1602        that is needed.
1604     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1605        as "const" (a) because they are and (b) because it helps the PHP
1606        maintainers who have recently made a script to detect big data structures
1607        in the php code that should be moved to the .rodata section. I remembered
1608        to update Builducptable as well, so it won't revert if ucptable.h is ever
1609        re-created.
1611     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1612        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1613        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1614        support is not required. This saves 1.5-2K of code, which is important in
1615        some applications.
1617        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1618        so as not to refer to the tables, even though these functions will never be
1619        called when UTF-8 support is disabled. Otherwise there are problems with a
1620        shared library.
1622    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1624        (a) It was defining its arguments as char * instead of void *.
1626        (b) It was assuming that all moves were upwards in memory; this was true
1627            a long time ago when I wrote it, but is no longer the case.
1629        The emulated memove() is provided for those environments that have neither
1630        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1631        is clearly not the case, as these two bugs were recently reported.
1633    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1634        and Detrail to create the HTML documentation, the .txt form of the man
1635        pages, and it removes trailing spaces from listed files. It also creates
1636        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1637        case, it wraps all the #defines with #ifndefs. This script should be run
1638        before "make dist".
1640    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1641        with Unicode property support.
1643        (a) For a maximizing quantifier, if the two different cases of the
1644            character were of different lengths in their UTF-8 codings (there are
1645            some cases like this - I found 11), and the matching function had to
1646            back up over a mixture of the two cases, it incorrectly assumed they
1647            were both the same length.
1649        (b) When PCRE was configured to use the heap rather than the stack for
1650            recursion during matching, it was not correctly preserving the data for
1651            the other case of a UTF-8 character when checking ahead for a match
1652            while processing a minimizing repeat. If the check also involved
1653            matching a wide character, but failed, corruption could cause an
1654            erroneous result when trying to check for a repeat of the original
1655            character.
1657    13. Some tidying changes to the testing mechanism:
1659        (a) The RunTest script now detects the internal link size and whether there
1660            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1661            values substituted by "configure". (The RunGrepTest script already did
1662            this for UTF-8.) The configure.ac script no longer substitutes the
1663            relevant variables.
1665        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1666            with length and offset values. This means that the output is different
1667            for different internal link sizes. Test 2 is skipped for link sizes
1668            other than 2 because of this, bypassing the problem. Unfortunately,
1669            there was also a test in test 3 (the locale tests) that used /B and
1670            failed for link sizes other than 2. Rather than cut the whole test out,
1671            I have added a new /Z option to pcretest that replaces the length and
1672            offset values with spaces. This is now used to make test 3 independent
1673            of link size. (Test 2 will be tidied up later.)
1675    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1676        segmentation fault instead of returning the appropriate error message.
1678    15. In multiline mode when the newline sequence was set to "any", the pattern
1679        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1680        This doesn't seem right; it now treats the CRLF combination as the line
1681        ending, and so does not match in that case. It's only a pattern such as ^$
1682        that would hit this one: something like ^ABC$ would have failed after \r
1683        and then tried again after \r\n.
1685    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1686        in an attempt to make files that differ only in their line terminators
1687        compare equal. This works on Linux.
1689    17. Under certain error circumstances pcregrep might try to free random memory
1690        as it exited. This is now fixed, thanks to valgrind.
1692    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1693        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1694        was because its rules for how to advance for /g after matching an empty
1695        string at the end of a line did not allow for this case. They now check for
1696        it specially.
1698    20. pcretest is supposed to handle patterns and data of any length, by
1699        extending its buffers when necessary. It was getting this wrong when the
1700        buffer for a data line had to be extended.
1702    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1703        CRLF as a newline sequence.
1705    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1706        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1707        I have nevertheless tidied it up.
1709    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1711    24. Added a man page for pcre-config.
1714    Version 7.0 19-Dec-06
1715    ---------------------
1717     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1718        moving to gcc 4.1.1.
1720     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1721        sys/time.h, which is documented as needed for this function. It doesn't
1722        seem to matter on Linux, but it showed up on some releases of OS X.
1724     3. It seems that there are systems where bytes whose values are greater than
1725        127 match isprint() in the "C" locale. The "C" locale should be the
1726        default when a C program starts up. In most systems, only ASCII printing
1727        characters match isprint(). This difference caused the output from pcretest
1728        to vary, making some of the tests fail. I have changed pcretest so that:
1730        (a) When it is outputting text in the compiled version of a pattern, bytes
1731            other than 32-126 are always shown as hex escapes.
1733        (b) When it is outputting text that is a matched part of a subject string,
1734            it does the same, unless a different locale has been set for the match
1735            (using the /L modifier). In this case, it uses isprint() to decide.
1737     4. Fixed a major bug that caused incorrect computation of the amount of memory
1738        required for a compiled pattern when options that changed within the
1739        pattern affected the logic of the preliminary scan that determines the
1740        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1741        that the computed length was too small. The symptoms of this bug were
1742        either the PCRE error "internal error: code overflow" from pcre_compile(),
1743        or a glibc crash with a message such as "pcretest: free(): invalid next
1744        size (fast)". Examples of patterns that provoked this bug (shown in
1745        pcretest format) are:
1747          /(?-x: )/x
1748          /(?x)(?-x: \s*#\s*)/
1749          /((?i)[\x{c0}])/8
1750          /(?i:[\x{c0}])/8
1752        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1753        is now done differently.
1755     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1756        wrapper classes; (b) implement a new function in the C++ scanner that is
1757        more efficient than the old way of doing things because it avoids levels of
1758        recursion in the regex matching; (c) add a paragraph to the documentation
1759        for the FullMatch() function.
1761     6. The escape sequence \n was being treated as whatever was defined as
1762        "newline". Not only was this contrary to the documentation, which states
1763        that \n is character 10 (hex 0A), but it also went horribly wrong when
1764        "newline" was defined as CRLF. This has been fixed.
1766     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1767        was being set to -1 for the "end of line" case (supposedly a value that no
1768        character can have). Though this value is never used (the check for end of
1769        line is "zero bytes in current character"), it caused compiler complaints.
1770        I've changed it to 0xffffffff.
1772     8. In pcre_version.c, the version string was being built by a sequence of
1773        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1774        string (as it is for production releases) called a macro with an empty
1775        argument. The C standard says the result of this is undefined. The gcc
1776        compiler treats it as an empty string (which was what was wanted) but it is
1777        reported that Visual C gives an error. The source has been hacked around to
1778        avoid this problem.
1780     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1781        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1782        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1783        of them did).
1785    10. Originally, pcretest opened its input and output without "b"; then I was
1786        told that "b" was needed in some environments, so it was added for release
1787        5.0 to both the input and output. (It makes no difference on Unix-like
1788        systems.) Later I was told that it is wrong for the input on Windows. I've
1789        now abstracted the modes into two macros, to make it easier to fiddle with
1790        them, and removed "b" from the input mode under Windows.
1792    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1794    12. Added -help and --help to pcretest as an official way of being reminded
1795        of the options.
1797    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1798        and pcrecpp.cc because they annoy compilers at high warning levels.
1800    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1802    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1803        scripts are not C programs :-) and which was not noticed because it works
1804        on Linux.
1806    16. pcretest is supposed to handle any length of pattern and data line (as one
1807        line or as a continued sequence of lines) by extending its input buffer if
1808        necessary. This feature was broken for very long pattern lines, leading to
1809        a string of junk being passed to pcre_compile() if the pattern was longer
1810        than about 50K.
1812    17. I have done a major re-factoring of the way pcre_compile() computes the
1813        amount of memory needed for a compiled pattern. Previously, there was code
1814        that made a preliminary scan of the pattern in order to do this. That was
1815        OK when PCRE was new, but as the facilities have expanded, it has become
1816        harder and harder to keep it in step with the real compile phase, and there
1817        have been a number of bugs (see for example, 4 above). I have now found a
1818        cunning way of running the real compile function in a "fake" mode that
1819        enables it to compute how much memory it would need, while actually only
1820        ever using a few hundred bytes of working memory and without too many
1821        tests of the mode. This should make future maintenance and development
1822        easier. A side effect of this work is that the limit of 200 on the nesting
1823        depth of parentheses has been removed (though this was never a serious
1824        limitation, I suspect). However, there is a downside: pcre_compile() now
1825        runs more slowly than before (30% or more, depending on the pattern). I
1826        hope this isn't a big issue. There is no effect on runtime performance.
1828    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1829        newline (only possible for the last line of a file) and it was a
1830        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1832    19. Added additional timing features to pcretest. (1) The -tm option now times
1833        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1834        separate command line item, by a number that specifies the number of
1835        repeats to use when timing. The default is 50000; this gives better
1836        precision, but takes uncomfortably long for very large patterns.
1838    20. Extended pcre_study() to be more clever in cases where a branch of a
1839        subpattern has no definite first character. For example, (a*|b*)[cd] would
1840        previously give no result from pcre_study(). Now it recognizes that the
1841        first character must be a, b, c, or d.
1843    21. There was an incorrect error "recursive call could loop indefinitely" if
1844        a subpattern (or the entire pattern) that was being tested for matching an
1845        empty string contained only one non-empty item after a nested subpattern.
1846        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1847        incorrectly, because the \d was being skipped in the check.
1849    22. The pcretest program now has a new pattern option /B and a command line
1850        option -b, which is equivalent to adding /B to every pattern. This causes
1851        it to show the compiled bytecode, without the additional information that
1852        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1853        is the same as /B/I).
1855    23. A new optimization is now able automatically to treat some sequences such
1856        as a*b as a*+b. More specifically, if something simple (such as a character
1857        or a simple class like \d) has an unlimited quantifier, and is followed by
1858        something that cannot possibly match the quantified thing, the quantifier
1859        is automatically "possessified".
1861    24. A recursive reference to a subpattern whose number was greater than 39
1862        went wrong under certain circumstances in UTF-8 mode. This bug could also
1863        have affected the operation of pcre_study().
1865    25. Realized that a little bit of performance could be had by replacing
1866        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1868    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1870    27. Possessive quantifiers such as a++ were previously implemented by turning
1871        them into atomic groups such as ($>a+). Now they have their own opcodes,
1872        which improves performance. This includes the automatically created ones
1873        from 23 above.
1875    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1876        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1877        the first matched character to be a colon. This applied both to named and
1878        numbered groups.
1880    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1882    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1883        building PCRE on Windows easier, so I have included it in the distribution.
1885    31. There is now a check in pcretest against a ridiculously large number being
1886        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1887        loop, the loop is abandoned.
1889    32. Forward references to subpatterns in conditions such as (?(2)...) where
1890        subpattern 2 is defined later cause pcre_compile() to search forwards in
1891        the pattern for the relevant set of parentheses. This search went wrong
1892        when there were unescaped parentheses in a character class, parentheses
1893        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1895    33. "Subroutine" calls and backreferences were previously restricted to
1896        referencing subpatterns earlier in the regex. This restriction has now
1897        been removed.
1899    34. Added a number of extra features that are going to be in Perl 5.10. On the
1900        whole, these are just syntactic alternatives for features that PCRE had
1901        previously implemented using the Python syntax or my own invention. The
1902        other formats are all retained for compatibility.
1904        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1905            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1906            also .NET compatible.
1908        (b) A recursion or subroutine call to a named group can now be defined as
1909            (?&name) as well as (?P>name).
1911        (c) A backreference to a named group can now be defined as \k<name> or
1912            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1913            5.10, are also .NET compatible.
1915        (d) A conditional reference to a named group can now use the syntax
1916            (?(<name>) or (?('name') as well as (?(name).
1918        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1919            groups (named and numbered) that are never evaluated inline, but can be
1920            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1921            is always false. There may be only one alternative in such a group.
1923        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1924            as the simple (?(R). The condition is true only if the most recent
1925            recursion is that of the given number or name. It does not search out
1926            through the entire recursion stack.
1928        (g) The escape \gN or \g{N} has been added, where N is a positive or
1929            negative number, specifying an absolute or relative reference.
1931    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1932        some "unreachable code" warnings.
1934    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1935        things, this adds five new scripts.
1937    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1938        There were also incompatibilities regarding the handling of \Q..\E inside
1939        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1940        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1942    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1943        matches an empty string, and forcibly breaks the loop. There were bugs in
1944        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1945        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1946        separate and independent bugs (that affected different cases) have been
1947        fixed.
1949    39. Refactored the code to abolish the use of different opcodes for small
1950        capturing bracket numbers. This is a tidy that I avoided doing when I
1951        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1952        The new approach is not only tidier, it makes it possible to reduce the
1953        memory needed to fix the previous bug (38).
1955    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1956        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1957        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1958        mode.
1960    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1961        report.
1963    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1964        copy construction and assignment in the C++ wrapper.
1966    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1967        couple of bugs that could have given wrong results in the "--newline=crlf"
1968        case.
1970    44. Added a number of casts and did some reorganization of signed/unsigned int
1971        variables following suggestions from Dair Grant. Also renamed the variable
1972        "this" as "item" because it is a C++ keyword.
1974    45. Arranged for dftables to add
1976          #include "pcre_internal.h"
1978        to pcre_chartables.c because without it, gcc 4.x may remove the array
1979        definition from the final binary if PCRE is built into a static library and
1980        dead code stripping is activated.
1982    46. For an unanchored pattern, if a match attempt fails at the start of a
1983        newline sequence, and the newline setting is CRLF or ANY, and the next two
1984        characters are CRLF, advance by two characters instead of one.
1987    Version 6.7 04-Jul-06
1988    ---------------------
1990     1. In order to handle tests when input lines are enormously long, pcretest has
1991        been re-factored so that it automatically extends its buffers when
1992        necessary. The code is crude, but this _is_ just a test program. The
1993        default size has been increased from 32K to 50K.
1995     2. The code in pcre_study() was using the value of the re argument before
1996        testing it for NULL. (Of course, in any sensible call of the function, it
1997        won't be NULL.)
1999     3. The memmove() emulation function in pcre_internal.h, which is used on
2000        systems that lack both memmove() and bcopy() - that is, hardly ever -
2001        was missing a "static" storage class specifier.
2003     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
2004        containing an extended class (one that cannot be represented by a bitmap
2005        because it contains high-valued characters or Unicode property items, e.g.
2006        [\pZ]). Almost always one would set UTF-8 mode when processing such a
2007        pattern, but PCRE should not loop if you do not (it no longer does).
2008        [Detail: two cases were found: (a) a repeated subpattern containing an
2009        extended class; (b) a recursive reference to a subpattern that followed a
2010        previous extended class. It wasn't skipping over the extended class
2011        correctly when UTF-8 mode was not set.]
2013     5. A negated single-character class was not being recognized as fixed-length
2014        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
2015        compile error "lookbehind assertion is not fixed length".
2017     6. The RunPerlTest auxiliary script was showing an unexpected difference
2018        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
2019        write a Perl script that can interpret lines of an input file either as
2020        byte characters or as UTF-8, which is what "perltest" was being required to
2021        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
2022        can't do is switch easily at run time between having the "use utf8;" pragma
2023        or not. In the end, I fudged it by using the RunPerlTest script to insert
2024        "use utf8;" explicitly for the UTF-8 tests.
2026     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
2027        the end of the subject string, contrary to the documentation and to what
2028        Perl does. This was true of both matching functions. Now it matches only at
2029        the start of the subject and immediately after *internal* newlines.
2031     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
2032        a pointer to an int instead of a pointer to an unsigned long int. This
2033        caused problems on 64-bit systems.
2035     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
2036        instance of the 'standard' template library not being so standard".
2038    10. There was no check on the number of named subpatterns nor the maximum
2039        length of a subpattern name. The product of these values is used to compute
2040        the size of the memory block for a compiled pattern. By supplying a very
2041        long subpattern name and a large number of named subpatterns, the size
2042        computation could be caused to overflow. This is now prevented by limiting
2043        the length of names to 32 characters, and the number of named subpatterns
2044        to 10,000.
2046    11. Subpatterns that are repeated with specific counts have to be replicated in
2047        the compiled pattern. The size of memory for this was computed from the
2048        length of the subpattern and the repeat count. The latter is limited to
2049        65535, but there was no limit on the former, meaning that integer overflow
2050        could in principle occur. The compiled length of a repeated subpattern is
2051        now limited to 30,000 bytes in order to prevent this.
2053    12. Added the optional facility to have named substrings with the same name.
2055    13. Added the ability to use a named substring as a condition, using the
2056        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
2057        are numbers (not recommended). Forward references are permitted.
2059    14. Added forward references in named backreferences (if you see what I mean).
2061    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
2062        pattern could run off the end of the subject. For example, the pattern
2063        "(?s)(.{1,5})"8 did this with the subject "ab".
2065    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
2066        PCRE_CASELESS was set when matching characters that were quantified with ?
2067        or *.
2069    17. A character class other than a single negated character that had a minimum
2070        but no maximum quantifier - for example [ab]{6,} - was not handled
2071        correctly by pce_dfa_exec(). It would match only one character.
2073    18. A valid (though odd) pattern that looked like a POSIX character
2074        class but used an invalid character after [ (for example [[,abc,]]) caused
2075        pcre_compile() to give the error "Failed: internal error: code overflow" or
2076        in some cases to crash with a glibc free() error. This could even happen if
2077        the pattern terminated after [[ but there just happened to be a sequence of
2078        letters, a binary zero, and a closing ] in the memory that followed.
2080    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
2081        over the years. Originally (before any Unicode support), just the bottom 8
2082        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
2083        output from "man perlunicode" includes this:
2085          The regular expression compiler produces polymorphic opcodes.  That
2086          is, the pattern adapts to the data and automatically switches to
2087          the Unicode character scheme when presented with Unicode data--or
2088          instead uses a traditional byte scheme when presented with byte
2089          data.
2091        Sadly, a wide octal escape does not cause a switch, and in a string with
2092        no other multibyte characters, these octal escapes are treated as before.
2093        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2094        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2095        Unicode string.
2097        I have not perpetrated such confusion in PCRE. Up till now, it took just
2098        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2099        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2100        translate to the appropriate multibyte character.
2102    29. Applied some refactoring to reduce the number of warnings from Microsoft
2103        and Borland compilers. This has included removing the fudge introduced
2104        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2105        a warning about an unused variable.
2107    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2108        characters since release 4.0, because Perl (from release 5.004) does not.
2109        [Or at least, is documented not to: some releases seem to be in conflict
2110        with the documentation.] However, when a pattern was studied with
2111        pcre_study() and all its branches started with \s, PCRE still included VT
2112        as a possible starting character. Of course, this did no harm; it just
2113        caused an unnecessary match attempt.
2115    22. Removed a now-redundant internal flag bit that recorded the fact that case
2116        dependency changed within the pattern. This was once needed for "required
2117        byte" processing, but is no longer used. This recovers a now-scarce options
2118        bit. Also moved the least significant internal flag bit to the most-
2119        significant bit of the word, which was not previously used (hangover from
2120        the days when it was an int rather than a uint) to free up another bit for
2121        the future.
2123    23. Added support for CRLF line endings as well as CR and LF. As well as the
2124        default being selectable at build time, it can now be changed at runtime
2125        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2126        specify that it is scanning data with non-default line endings.
2128    24. Changed the definition of CXXLINK to make it agree with the definition of
2129        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2131    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2132        recursions. This makes a big different to stack usage for some patterns.
2134    26. If a subpattern containing a named recursion or subroutine reference such
2135        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2136        the space required for the compiled pattern went wrong and gave too small a
2137        value. Depending on the environment, this could lead to "Failed: internal
2138        error: code overflow at offset 49" or "glibc detected double free or
2139        corruption" errors.
2141    27. Applied patches from Google (a) to support the new newline modes and (b) to
2142        advance over multibyte UTF-8 characters in GlobalReplace.
2144    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2145        difference for some implementation of PCRE in some Windows version.
2147    29. Added some extra testing facilities to pcretest:
2149        \q<number>   in a data line sets the "match limit" value
2150        \Q<number>   in a data line sets the "match recursion limt" value
2151        -S <number>  sets the stack size, where <number> is in megabytes
2153        The -S option isn't available for Windows.
2156    Version 6.6 06-Feb-06
2157    ---------------------
2159     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2160        in pcreposix.h. I have copied the definition from pcre.h.
2162     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2163        because pcre.h is no longer a built file.
2165     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2166        not normally included in the compiled code.
2169    Version 6.5 01-Feb-06
2170    ---------------------
2172     1. When using the partial match feature with pcre_dfa_exec(), it was not
2173        anchoring the second and subsequent partial matches at the new starting
2174        point. This could lead to incorrect results. For example, with the pattern
2175        /1234/, partially matching against "123" and then "a4" gave a match.
2177     2. Changes to pcregrep:
2179        (a) All non-match returns from pcre_exec() were being treated as failures
2180            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2181            error message is output. Some extra information is given for the
2182            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2183            probably the only errors that are likely to be caused by users (by
2184            specifying a regex that has nested indefinite repeats, for instance).
2185            If there are more than 20 of these errors, pcregrep is abandoned.
2187        (b) A binary zero was treated as data while matching, but terminated the
2188            output line if it was written out. This has been fixed: binary zeroes
2189            are now no different to any other data bytes.
2191        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2192            used to set a locale for matching. The --locale=xxxx long option has
2193            been added (no short equivalent) to specify a locale explicitly on the
2194            pcregrep command, overriding the environment variables.
2196        (d) When -B was used with -n, some line numbers in the output were one less
2197            than they should have been.
2199        (e) Added the -o (--only-matching) option.
2201        (f) If -A or -C was used with -c (count only), some lines of context were
2202            accidentally printed for the final match.
2204        (g) Added the -H (--with-filename) option.
2206        (h) The combination of options -rh failed to suppress file names for files
2207            that were found from directory arguments.
2209        (i) Added the -D (--devices) and -d (--directories) options.
2211        (j) Added the -F (--fixed-strings) option.
2213        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2215        (l) Added the --colo(u)r option.
2217        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2218            is not present by default.
2220     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2221        items such as (?R) or (?1), when the recursion could match a number of
2222        alternatives. If it matched one of the alternatives, but subsequently,
2223        outside the recursion, there was a failure, the code tried to back up into
2224        the recursion. However, because of the way PCRE is implemented, this is not
2225        possible, and the result was an incorrect result from the match.
2227        In order to prevent this happening, the specification of recursion has
2228        been changed so that all such subpatterns are automatically treated as
2229        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2231     4. I had overlooked the fact that, in some locales, there are characters for
2232        which isalpha() is true but neither isupper() nor islower() are true. In
2233        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2234        and ordfeminine) are like this. This affected the treatment of \w and \W
2235        when they appeared in character classes, but not when they appeared outside
2236        a character class. The bit map for "word" characters is now created
2237        separately from the results of isalnum() instead of just taking it from the
2238        upper, lower, and digit maps. (Plus the underscore character, of course.)
2240     5. The above bug also affected the handling of POSIX character classes such as
2241        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2242        permanent tables. Instead, the bit maps for such a class were previously
2243        created as the appropriate unions of the upper, lower, and digit bitmaps.
2244        Now they are created by subtraction from the [[:word:]] class, which has
2245        its own bitmap.
2247     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2248        It is created by subtracting the vertical space characters (\x09, \x0a,
2249        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2250        subtraction was done in the overall bitmap for a character class, meaning
2251        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2252        be recognized. This bug has been fixed.
2254     7. Patches from the folks at Google:
2256          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2257          real life, but is still worth protecting against".
2259          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2260          regular expressions".
2262          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2263          have it.
2265          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2266          "configure" and the latter not, in order to fix a problem somebody had
2267          with compiling the Arg class on HP-UX.
2269          (e) Improve the error-handling of the C++ wrapper a little bit.
2271          (f) New tests for checking recursion limiting.
2273     8. The pcre_memmove() function, which is used only if the environment does not
2274        have a standard memmove() function (and is therefore rarely compiled),
2275        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2276        returning a result (though PCRE never actually uses the result).
2278     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2279        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2280        returned instead of calling malloc() with an overflowing number that would
2281        most likely cause subsequent chaos.
2283    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2285    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2286        with this option is matched, the nmatch and pmatch options of regexec() are
2287        ignored.
2289    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2290        provided in case anyone wants to the the POSIX interface with UTF-8
2291        strings.
2293    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2294        C++ linking (needed for some HP-UX environments).
2296    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2297        (unused parameter) and in the pcre_printint() function (omitted "default"
2298        switch label when the default is to do nothing).
2300    15. Added some code to make it possible, when PCRE is compiled as a C++
2301        library, to replace subject pointers for pcre_exec() with a smart pointer
2302        class, thus making it possible to process discontinuous strings.
2304    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2305        much the same function. They were added by different people who were trying
2306        to make PCRE easy to compile on non-Unix systems. It has been suggested
2307        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2308        for compiling on Windows systems. I have therefore replaced it with
2309        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2310        defaults to "extern" for C or "extern C" for C++, which works fine on
2311        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2312        SCOPE with something explicit in config.h. In addition:
2314        (a) pcreposix.h still had just "extern" instead of either of these macros;
2315            I have replaced it with PCRE_DATA_SCOPE.
2317        (b) Functions such as _pcre_xclass(), which are internal to the library,
2318            but external in the C sense, all had PCRE_EXPORT in their definitions.
2319            This is apparently wrong for the Windows case, so I have removed it.
2320            (It makes no difference on Unix-like systems.)
2322    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2323        of recursive calls to match(). This is different to MATCH_LIMIT because
2324        that limits the total number of calls to match(), not all of which increase
2325        the depth of recursion. Limiting the recursion depth limits the amount of
2326        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2327        when PCRE is compiled, and changed at run time. A patch from Google adds
2328        this functionality to the C++ interface.
2330    18. Changes to the handling of Unicode character properties:
2332        (a) Updated the table to Unicode 4.1.0.
2334        (b) Recognize characters that are not in the table as "Cn" (undefined).
2336        (c) I revised the way the table is implemented to a much improved format
2337            which includes recognition of ranges. It now supports the ranges that
2338            are defined in UnicodeData.txt, and it also amalgamates other
2339            characters into ranges. This has reduced the number of entries in the
2340            table from around 16,000 to around 3,000, thus reducing its size
2341            considerably. I realized I did not need to use a tree structure after
2342            all - a binary chop search is just as efficient. Having reduced the
2343            number of entries, I extended their size from 6 bytes to 8 bytes to
2344            allow for more data.
2346        (d) Added support for Unicode script names via properties such as \p{Han}.
2348    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2349        matching that character.
2351    20. When matching a repeated Unicode property with a minimum greater than zero,
2352        (for example \pL{2,}), PCRE could look past the end of the subject if it
2353        reached it while seeking the minimum number of characters. This could
2354        happen only if some of the characters were more than one byte long, because
2355        there is a check for at least the minimum number of bytes.
2357    21. Refactored the implementation of \p and \P so as to be more general, to
2358        allow for more different types of property in future. This has changed the
2359        compiled form incompatibly. Anybody with saved compiled patterns that use
2360        \p or \P will have to recompile them.
2362    22. Added "Any" and "L&" to the supported property types.
2364    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2365        but give a compile time error if the value is greater than 0xff.
2367    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2368        accidentally not being installed or uninstalled.
2370    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2371        made were to insert the current release number. This seemed silly, because
2372        it made things harder for people building PCRE on systems that don't run
2373        "configure". I have turned pcre.h into a distributed file, no longer built
2374        by "configure", with the version identification directly included. There is
2375        no longer a pcre.h.in file.
2377        However, this change necessitated a change to the pcre-config script as
2378        well. It is built from pcre-config.in, and one of the substitutions was the
2379        release number. I have updated configure.ac so that ./configure now finds
2380        the release number by grepping pcre.h.
2382    26. Added the ability to run the tests under valgrind.
2385    Version 6.4 05-Sep-05
2386    ---------------------
2388     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2389        "--" to be printed when multiple files were scanned, even when none of the
2390        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2391        consider it to be a bug, and have restored the previous behaviour.
2393     2. A couple of code tidies to get rid of compiler warnings.
2395     3. The pcretest program used to cheat by referring to symbols in the library
2396        whose names begin with _pcre_. These are internal symbols that are not
2397        really supposed to be visible externally, and in some environments it is
2398        possible to suppress them. The cheating is now confined to including
2399        certain files from the library's source, which is a bit cleaner.
2401     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2402        file's purpose clearer.
2404     5. Reorganized pcre_ucp_findchar().
2407    Version 6.3 15-Aug-05
2408    ---------------------
2410     1. The file libpcre.pc.in did not have general read permission in the tarball.
2412     2. There were some problems when building without C++ support:
2414        (a) If C++ support was not built, "make install" and "make test" still
2415            tried to test it.
2417        (b) There were problems when the value of CXX was explicitly set. Some
2418            changes have been made to try to fix these, and ...
2420        (c) --disable-cpp can now be used to explicitly disable C++ support.
2422        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2423            backslash in a target when C++ was disabled. This confuses some
2424            versions of "make", apparently. Using an intermediate variable solves
2425            this. (Same for CPP_LOBJ.)
2427     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2428        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2429        necessary on certain architectures.
2431     4. Added a setting of -export-symbols-regex to the link command to remove
2432        those symbols that are exported in the C sense, but actually are local
2433        within the library, and not documented. Their names all begin with
2434        "_pcre_". This is not a perfect job, because (a) we have to except some
2435        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2436        available (and never for static libraries). I have made a note to try to
2437        find a way round (a) in the future.
2440    Version 6.2 01-Aug-05
2441    ---------------------
2443     1. There was no test for integer overflow of quantifier values. A construction
2444        such as {1111111111111111} would give undefined results. What is worse, if
2445        a minimum quantifier for a parenthesized subpattern overflowed and became
2446        negative, the calculation of the memory size went wrong. This could have
2447        led to memory overwriting.
2449     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2451     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2452        operating environments where this matters.
2454     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2455        PCRE options from within the C++ wrapper.
2457     5. Named capturing subpatterns were not being correctly counted when a pattern
2458        was compiled. This caused two problems: (a) If there were more than 100
2459        such subpatterns, the calculation of the memory needed for the whole
2460        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2461        back references of the form \12, where the number was greater than 9, were
2462        not recognized as back references, even though there were sufficient
2463        previous subpatterns.
2465     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2466        versions of gcc, e.g. 2.95.4.
2469    Version 6.1 21-Jun-05
2470    ---------------------
2472     1. There was one reference to the variable "posix" in pcretest.c that was not
2473        surrounded by "#if !defined NOPOSIX".
2475     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2476        the cross-check on the old pcre_info() function, for the benefit of the
2477        cut-down version of PCRE that is currently imported into Exim.
2479     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2480        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2481        patterns that start (?i) but I don't think that matters. The use of (?i) is
2482        just an example; this all applies to the other options as well.
2484     4. Since libtool seems to echo the compile commands it is issuing, the output
2485        from "make" can be reduced a bit by putting "@" in front of each libtool
2486        compile command.
2488     5. Patch from the folks at Google for configure.in to be a bit more thorough
2489        in checking for a suitable C++ installation before trying to compile the
2490        C++ stuff. This should fix a reported problem when a compiler was present,
2491        but no suitable headers.
2493     6. The man pages all had just "PCRE" as their title. I have changed them to
2494        be the relevant file name. I have also arranged that these names are
2495        retained in the file doc/pcre.txt, which is a concatenation in text format
2496        of all the man pages except the little individual ones for each function.
2498     7. The NON-UNIX-USE file had not been updated for the different set of source
2499        files that come with release 6. I also added a few comments about the C++
2500        wrapper.
2503  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
2504  ---------------------  ---------------------

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