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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.11 10-Oct-2010
5    ------------------------
7    1.  (*THEN) was not working properly if there were untried alternatives prior
8        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9        backtracked to try for "b" instead of moving to the next alternative branch
10        at the same level (in this case, to look for "c"). The Perl documentation
11        is clear that when (*THEN) is backtracked onto, it goes to the "next
12        alternative in the innermost enclosing group".
14    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
16        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18        (*THEN).
20    3.  If \s appeared in a character class, it removed the VT character from
21        the class, even if it had been included by some previous item, for example
22        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
23        of \s, but is part of the POSIX "space" class.)
25    4.  A partial match never returns an empty string (because you can always
26        match an empty string at the end of the subject); however the checking for
27        an empty string was starting at the "start of match" point. This has been
28        changed to the "earliest inspected character" point, because the returned
29        data for a partial match starts at this character. This means that, for
30        example, /(?<=abc)def/ gives a partial match for the subject "abc"
31        (previously it gave "no match").
33    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
34        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
35        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
36        has an implication that the given string is incomplete (because a partial
37        match is preferred over a full match). For this reason, these items now
38        give a partial match in this situation. [Aside: previously, the one case
39        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
40        match rather than a full match, which was wrong by the old rules, but is
41        now correct.]
43    6.  There was a bug in the handling of #-introduced comments, recognized when
44        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
45        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
46        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
47        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
48        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
49        places in pcre_compile().
51    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
52        comments when looking ahead for named forward references to subpatterns,
53        the only newline sequence it recognized was NL. It now handles newlines
54        according to the set newline convention.
56    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
57        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
58        cater for a lack of strerror(). These oversights have been fixed.
60    9.  Added --match-limit and --recursion-limit to pcregrep.
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
64    11. When the -o option was used, pcregrep was setting a return code of 1, even
65        when matches were found, and --line-buffered was not being honoured.
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
70    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
71        can match an empty string. The code to do it in pcretest and pcredemo
72        needed fixing:
74        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
75            only one byte after an empty string match just before CRLF (this case
76            just got forgotten; "any" and "anycrlf" were OK).
78        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
79            mode when an empty string match preceded an ASCII character followed by
80            a non-ASCII character. (The code for advancing by one character rather
81            than one byte was nonsense.)
83        (c) The pcredemo.c sample program did not have any code at all to handle
84            the cases when CRLF is a valid newline sequence.
86    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
87        as a starting offset was within the subject string. There is now a new
88        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
89        negative or greater than the length of the string. In order to test this,
90        pcretest is extended to allow the setting of negative starting offsets.
92    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
93        starting offset points to the beginning of a UTF-8 character was
94        unnecessarily clumsy. I tidied it up.
96    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
97        bad UTF-8 sequence and one that is incomplete.
99    17. Nobody had reported that the --include_dir option, which was added in
100        release 7.7 should have been called --include-dir (hyphen, not underscore)
101        for compatibility with GNU grep. I have changed it to --include-dir, but
102        left --include_dir as an undocumented synonym, and the same for
103        --exclude-dir, though that is not available in GNU grep, at least as of
104        release 2.5.4.
106    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
107        characters from a string of bytes) have been redefined so as not to use
108        loops, in order to improve performance in some environments. At the same
109        time, I abstracted some of the common code into auxiliary macros to save
110        repetition (this should not affect the compiled code).
112    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
113        compile-time error is now given if \c is not followed by an ASCII
114        character, that is, a byte less than 128. (In EBCDIC mode, the code is
115        different, and any byte value is allowed.)
117    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
118        START_OPTIMIZE option, which is now allowed at compile time - but just
119        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
120        to pcregrep and other applications that have no direct access to PCRE
121        options. The new /Y option in pcretest sets this option when calling
122        pcre_compile().
125    Version 8.10 25-Jun-2010
126    ------------------------
128    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
129        THEN.
131    2.  (*ACCEPT) was not working when inside an atomic group.
133    3.  Inside a character class, \B is treated as a literal by default, but
134        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
135        causes the error). The code is unchanged, but I tidied the documentation.
137    4.  Inside a character class, PCRE always treated \R and \X as literals,
138        whereas Perl faults them if its -w option is set. I have changed PCRE so
139        that it faults them when PCRE_EXTRA is set.
141    5.  Added support for \N, which always matches any character other than
142        newline. (It is the same as "." when PCRE_DOTALL is not set.)
144    6.  When compiling pcregrep with newer versions of gcc which may have
145        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
146        declared with attribute warn_unused_result" were given. Just casting the
147        result to (void) does not stop the warnings; a more elaborate fudge is
148        needed. I've used a macro to implement this.
150    7.  Minor change to pcretest.c to avoid a compiler warning.
152    8.  Added four artifical Unicode properties to help with an option to make
153        \s etc use properties (see next item). The new properties are: Xan
154        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
156    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
157        use Unicode properties. (*UCP) at the start of a pattern can be used to set
158        this option. Modified pcretest to add /W to test this facility. Added
159        REG_UCP to make it available via the POSIX interface.
161    10. Added --line-buffered to pcregrep.
163    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
164        studied, and the match started with a letter with a code point greater than
165        127 whose first byte was different to the first byte of the other case of
166        the letter, the other case of this starting letter was not recognized
167        (#976).
169    12. If a pattern that was studied started with a repeated Unicode property
170        test, for example, \p{Nd}+, there was the theoretical possibility of
171        setting up an incorrect bitmap of starting bytes, but fortunately it could
172        not have actually happened in practice until change 8 above was made (it
173        added property types that matched character-matching opcodes).
175    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
176        possible starting bytes for non-anchored patterns.
178    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
179        \R, and also a number of cases that involve Unicode properties, both
180        explicit and implicit when PCRE_UCP is set.
182    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
183        input, it could crash or give wrong results if characters with values
184        greater than 0xc0 were present in the subject string. (Detail: it assumed
185        UTF-8 input when processing these items.)
187    16. Added a lot of (int) casts to avoid compiler warnings in systems where
188        size_t is 64-bit (#991).
190    17. Added a check for running out of memory when PCRE is compiled with
191        --disable-stack-for-recursion (#990).
193    18. If the last data line in a file for pcretest does not have a newline on
194        the end, a newline was missing in the output.
196    19. The default pcre_chartables.c file recognizes only ASCII characters (values
197        less than 128) in its various bitmaps. However, there is a facility for
198        generating tables according to the current locale when PCRE is compiled. It
199        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
200        characters, are recognized by isspace() and therefore were getting set in
201        these tables, and indeed these tables seem to approximate to ISO 8859. This
202        caused a problem in UTF-8 mode when pcre_study() was used to create a list
203        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
204        which of course cannot start UTF-8 characters. I have changed the code so
205        that only real ASCII characters (less than 128) and the correct starting
206        bytes for UTF-8 encodings are set for characters greater than 127 when in
207        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
208        altogether.)
210    20. Added the /T option to pcretest so as to be able to run tests with non-
211        standard character tables, thus making it possible to include the tests
212        used for 19 above in the standard set of tests.
214    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
215        reference to a subpattern the other side of a comment that contains an
216        opening parenthesis caused either an internal compiling error, or a
217        reference to the wrong subpattern.
220    Version 8.02 19-Mar-2010
221    ------------------------
223    1.  The Unicode data tables have been updated to Unicode 5.2.0.
225    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
226        configured.
228    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
229        original author of that file, following a query about its status.
231    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
232        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
234    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
235        quantifier applied to a forward-referencing subroutine call, could compile
236        incorrect code or give the error "internal error: previously-checked
237        referenced subpattern not found".
239    6.  Both MS Visual Studio and Symbian OS have problems with initializing
240        variables to point to external functions. For these systems, therefore,
241        pcre_malloc etc. are now initialized to local functions that call the
242        relevant global functions.
244    7.  There were two entries missing in the vectors called coptable and poptable
245        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
246        I've fixed the data, and added a kludgy way of testing at compile time that
247        the lengths are correct (equal to the number of opcodes).
249    8.  Following on from 7, I added a similar kludge to check the length of the
250        eint vector in pcreposix.c.
252    9.  Error texts for pcre_compile() are held as one long string to avoid too
253        much relocation at load time. To find a text, the string is searched,
254        counting zeros. There was no check for running off the end of the string,
255        which could happen if a new error number was added without updating the
256        string.
258    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
260    11. \K was not working if it appeared in an atomic group or in a group that
261        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
262        \K is "not well defined" if used in an assertion. PCRE now accepts it if
263        the assertion is positive, but not if it is negative.
265    12. Change 11 fortuitously reduced the size of the stack frame used in the
266        "match()" function of pcre_exec.c by one pointer. Forthcoming
267        implementation of support for (*MARK) will need an extra pointer on the
268        stack; I have reserved it now, so that the stack frame size does not
269        decrease.
271    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
272        item in branch that calls a recursion is a subroutine call - as in the
273        second branch in the above example - was incorrectly given the compile-
274        time error "recursive call could loop indefinitely" because pcre_compile()
275        was not correctly checking the subroutine for matching a non-empty string.
277    14. The checks for overrunning compiling workspace could trigger after an
278        overrun had occurred. This is a "should never occur" error, but it can be
279        triggered by pathological patterns such as hundreds of nested parentheses.
280        The checks now trigger 100 bytes before the end of the workspace.
282    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
285    Version 8.01 19-Jan-2010
286    ------------------------
288    1.  If a pattern contained a conditional subpattern with only one branch (in
289        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
290        computed the wrong minimum data length (which is of course zero for such
291        subpatterns). This could cause incorrect "no match" results.
293    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
294        the pattern is reset in the first branch, pcre_compile() failed with
295        "internal error: code overflow at offset...". This happened only when
296        the reset was to the original external option setting. (An optimization
297        abstracts leading options settings into an external setting, which was the
298        cause of this.)
300    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
301        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
302        assertion pattern did not match (meaning that the assertion was true), it
303        was incorrectly treated as false if the SKIP had been reached during the
304        matching. This also applied to assertions used as conditions.
306    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
307        assertion subpattern, including such a pattern used as a condition,
308        unpredictable results occurred, instead of the error return
311    5.  The C++ GlobalReplace function was not working like Perl for the special
312        situation when an empty string is matched. It now does the fancy magic
313        stuff that is necessary.
315    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
316        removed. (These were left over from very, very early versions of PCRE.)
318    7.  Some cosmetic changes to the code to make life easier when compiling it
319        as part of something else:
321        (a) Change DEBUG to PCRE_DEBUG.
323        (b) In pcre_compile(), rename the member of the "branch_chain" structure
324            called "current" as "current_branch", to prevent a collision with the
325            Linux macro when compiled as a kernel module.
327        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
328            prevent a collision with the Linux macro when compiled as a kernel
329            module.
331    8.  In pcre_compile() there are some checks for integer overflows that used to
332        cast potentially large values to (double). This has been changed to that
333        when building, a check for int64_t is made, and if it is found, it is used
334        instead, thus avoiding the use of floating point arithmetic. (There is no
335        other use of FP in PCRE.) If int64_t is not found, the fallback is to
336        double.
338    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
339        2005 (difference between two addresses compared to an unsigned value).
341    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
342        custom one, because of the following reported problem in Windows:
344          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
345              under Win32.
346          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
347              therefore missing the function definition.
348          - The compiler thus generates a "C" signature for the test function.
349          - The linker fails to find the "C" function.
350          - PCRE fails to configure if asked to do so against libbz2.
352    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
353        messages were output:
355          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
356          rerunning libtoolize, to keep the correct libtool macros in-tree.
357          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
359        I have done both of these things.
361    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
362        most of the time, it *can* run out if it is given a pattern that contains a
363        runaway infinite recursion. I updated the discussion in the pcrestack man
364        page.
366    13. Now that we have gone to the x.xx style of version numbers, the minor
367        version may start with zero. Using 08 or 09 is a bad idea because users
368        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
369        interpreted as invalid octal numbers. I've updated the previous comment in
370        configure.ac, and also added a check that gives an error if 08 or 09 are
371        used.
373    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
374        causing partial matching to fail when the end of the subject matched \W
375        in a UTF-8 pattern where \W was quantified with a minimum of 3.
377    15. There were some discrepancies between the declarations in pcre_internal.h
378        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
379        their definitions. The declarations used "const uschar *" and the
380        definitions used USPTR. Even though USPTR is normally defined as "const
381        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
382        reported that: "This difference in casting confuses some C++ compilers, for
383        example, SunCC recognizes above declarations as different functions and
384        generates broken code for hbpcre." I have changed the declarations to use
385        USPTR.
387    16. GNU libtool is named differently on some systems. The autogen.sh script now
388        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
389        (FreeBSD).
391    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
392        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
393        comment: "Figure out how to create a longlong from a string: strtoll and
394        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
395        instance, but it only takes 2 args instead of 3!"
397    18. A subtle bug concerned with back references has been fixed by a change of
398        specification, with a corresponding code fix. A pattern such as
399        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
400        refers, was giving matches when it shouldn't. For example, xa=xaaa would
401        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
402        same bug. Such groups have to be quantified to be useful, or contained
403        inside another quantified group. (If there's no repetition, the reference
404        can never match.) The problem arises because, having left the group and
405        moved on to the rest of the pattern, a later failure that backtracks into
406        the group uses the captured value from the final iteration of the group
407        rather than the correct earlier one. I have fixed this in PCRE by forcing
408        any group that contains a reference to itself to be an atomic group; that
409        is, there cannot be any backtracking into it once it has completed. This is
410        similar to recursive and subroutine calls.
413    Version 8.00 19-Oct-09
414    ----------------------
416    1.  The table for translating pcre_compile() error codes into POSIX error codes
417        was out-of-date, and there was no check on the pcre_compile() error code
418        being within the table. This could lead to an OK return being given in
419        error.
421    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
422        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
423        in a Windows environment.
425    3.  The pcregrep --count option prints the count for each file even when it is
426        zero, as does GNU grep. However, pcregrep was also printing all files when
427        --files-with-matches was added. Now, when both options are given, it prints
428        counts only for those files that have at least one match. (GNU grep just
429        prints the file name in this circumstance, but including the count seems
430        more useful - otherwise, why use --count?) Also ensured that the
431        combination -clh just lists non-zero counts, with no names.
433    4.  The long form of the pcregrep -F option was incorrectly implemented as
434        --fixed_strings instead of --fixed-strings. This is an incompatible change,
435        but it seems right to fix it, and I didn't think it was worth preserving
436        the old behaviour.
438    5.  The command line items --regex=pattern and --regexp=pattern were not
439        recognized by pcregrep, which required --regex pattern or --regexp pattern
440        (with a space rather than an '='). The man page documented the '=' forms,
441        which are compatible with GNU grep; these now work.
443    6.  No libpcreposix.pc file was created for pkg-config; there was just
444        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
446    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
447        when UCP support is not needed, by modifying the Python script that
448        generates it from Unicode data files. This should not matter if the module
449        is correctly used as a library, but I received one complaint about 50K of
450        unwanted data. My guess is that the person linked everything into his
451        program rather than using a library. Anyway, it does no harm.
453    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
454        was a minimum greater than 1 for a wide character in a possessive
455        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
456        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
457        character. Chaos in the form of incorrect output or a compiling loop could
458        result.
460    9.  The restrictions on what a pattern can contain when partial matching is
461        requested for pcre_exec() have been removed. All patterns can now be
462        partially matched by this function. In addition, if there are at least two
463        slots in the offset vector, the offset of the earliest inspected character
464        for the match and the offset of the end of the subject are set in them when
465        PCRE_ERROR_PARTIAL is returned.
467    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
468        synonymous with PCRE_PARTIAL, for backwards compatibility, and
469        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
470        and may be more useful for multi-segment matching.
472    11. Partial matching with pcre_exec() is now more intuitive. A partial match
473        used to be given if ever the end of the subject was reached; now it is
474        given only if matching could not proceed because another character was
475        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
476        string "Z", which now yields "no match" instead of "partial match". In the
477        case of pcre_dfa_exec(), "no match" is given if every matching path for the
478        final character ended with (*FAIL).
480    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
481        if the pattern had a "must contain" character that was already found in the
482        earlier partial match, unless partial matching was again requested. For
483        example, with the pattern /dog.(body)?/, the "must contain" character is
484        "g". If the first part-match was for the string "dog", restarting with
485        "sbody" failed. This bug has been fixed.
487    13. The string returned by pcre_dfa_exec() after a partial match has been
488        changed so that it starts at the first inspected character rather than the
489        first character of the match. This makes a difference only if the pattern
490        starts with a lookbehind assertion or \b or \B (\K is not supported by
491        pcre_dfa_exec()). It's an incompatible change, but it makes the two
492        matching functions compatible, and I think it's the right thing to do.
494    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
495        so that the demonstration program is easily available in environments where
496        PCRE has not been installed from source.
498    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
499        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
500        library.
502    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
503        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
504        is not the first non-POSIX option to be added. Clearly some people find
505        these options useful.
507    17. If a caller to the POSIX matching function regexec() passes a non-zero
508        value for nmatch with a NULL value for pmatch, the value of
509        nmatch is forced to zero.
511    18. RunGrepTest did not have a test for the availability of the -u option of
512        the diff command, as RunTest does. It now checks in the same way as
513        RunTest, and also checks for the -b option.
515    19. If an odd number of negated classes containing just a single character
516        interposed, within parentheses, between a forward reference to a named
517        subpattern and the definition of the subpattern, compilation crashed with
518        an internal error, complaining that it could not find the referenced
519        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
520        [The bug was that it was starting one character too far in when skipping
521        over the character class, thus treating the ] as data rather than
522        terminating the class. This meant it could skip too much.]
524    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
525        /g option in pcretest when the pattern contains \K, which makes it possible
526        to have an empty string match not at the start, even when the pattern is
527        anchored. Updated pcretest and pcredemo to use this option.
529    21. If the maximum number of capturing subpatterns in a recursion was greater
530        than the maximum at the outer level, the higher number was returned, but
531        with unset values at the outer level. The correct (outer level) value is
532        now given.
534    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
535        PCRE did not set those parentheses (unlike Perl). I have now found a way to
536        make it do so. The string so far is captured, making this feature
537        compatible with Perl.
539    23. The tests have been re-organized, adding tests 11 and 12, to make it
540        possible to check the Perl 5.10 features against Perl 5.10.
542    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
543        pattern matches a fixed length string. PCRE did not allow this; now it
544        does. Neither allows recursion.
546    25. I finally figured out how to implement a request to provide the minimum
547        length of subject string that was needed in order to match a given pattern.
548        (It was back references and recursion that I had previously got hung up
549        on.) This code has now been added to pcre_study(); it finds a lower bound
550        to the length of subject needed. It is not necessarily the greatest lower
551        bound, but using it to avoid searching strings that are too short does give
552        some useful speed-ups. The value is available to calling programs via
553        pcre_fullinfo().
555    26. While implementing 25, I discovered to my embarrassment that pcretest had
556        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
557        study optimizations had never been tested with that matching function.
558        Oops. What is worse, even when it was passed study data, there was a bug in
559        pcre_dfa_exec() that meant it never actually used it. Double oops. There
560        were also very few tests of studied patterns with pcre_dfa_exec().
562    27. If (?| is used to create subpatterns with duplicate numbers, they are now
563        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
564        on the other side of the coin, they are no longer allowed to have different
565        names, because these cannot be distinguished in PCRE, and this has caused
566        confusion. (This is a difference from Perl.)
568    28. When duplicate subpattern names are present (necessarily with different
569        numbers, as required by 27 above), and a test is made by name in a
570        conditional pattern, either for a subpattern having been matched, or for
571        recursion in such a pattern, all the associated numbered subpatterns are
572        tested, and the overall condition is true if the condition is true for any
573        one of them. This is the way Perl works, and is also more like the way
574        testing by number works.
577    Version 7.9 11-Apr-09
578    ---------------------
580    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
581        (pcretest), all targets were linked against these libraries. This included
582        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
583        libraries. This caused unwanted dependencies to be created. This problem
584        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
585        pcretest is linked with readline.
587    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
588        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
589        moved outside it again, because FALSE and TRUE are already defined in AIX,
590        but BOOL is not.
592    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
593        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
595    4.  The pcregrep documentation said spaces were inserted as well as colons (or
596        hyphens) following file names and line numbers when outputting matching
597        lines. This is not true; no spaces are inserted. I have also clarified the
598        wording for the --colour (or --color) option.
600    5.  In pcregrep, when --colour was used with -o, the list of matching strings
601        was not coloured; this is different to GNU grep, so I have changed it to be
602        the same.
604    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
605        each matching line was coloured. Now it goes on to look for further matches
606        of any of the test patterns, which is the same behaviour as GNU grep.
608    7.  A pattern that could match an empty string could cause pcregrep to loop; it
609        doesn't make sense to accept an empty string match in pcregrep, so I have
610        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
611        seems to be how GNU grep behaves.
613    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
614        start or after a newline", because the conditional assertion was not being
615        correctly handled. The rule now is that both the assertion and what follows
616        in the first alternative must satisfy the test.
618    9.  If auto-callout was enabled in a pattern with a conditional group whose
619        condition was an assertion, PCRE could crash during matching, both with
620        pcre_exec() and pcre_dfa_exec().
622    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
623        used for matching.
625    11. Unicode property support in character classes was not working for
626        characters (bytes) greater than 127 when not in UTF-8 mode.
628    12. Added the -M command line option to pcretest.
630    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
632    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
634    16. Added comments and documentation about mis-use of no_arg in the C++
635        wrapper.
637    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
638        from Martin Jerabek that uses macro names for all relevant character and
639        string constants.
641    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
642        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
643        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
644        these, but not everybody uses configure.
646    19. A conditional group that had only one branch was not being correctly
647        recognized as an item that could match an empty string. This meant that an
648        enclosing group might also not be so recognized, causing infinite looping
649        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
650        with the subject "ab", where knowledge that the repeated group can match
651        nothing is needed in order to break the loop.
653    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
654        exec(), but without supplying a callout function, matching went wrong.
656    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
657        leak if the size of the offset vector was greater than 30. When the vector
658        is smaller, the saved offsets during recursion go onto a local stack
659        vector, but for larger vectors malloc() is used. It was failing to free
660        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
661        error, in fact).
663    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
664        heapframe that is used only when UTF-8 support is enabled. This caused no
665        problem, but was untidy.
667    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
668        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
669        included within another project.
671    24. Steven Van Ingelgem's patches to add more options to the CMake support,
672        slightly modified by me:
674          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
675              not building pcregrep.
677          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
678              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
680    25. Forward references, both numeric and by name, in patterns that made use of
681        duplicate group numbers, could behave incorrectly or give incorrect errors,
682        because when scanning forward to find the reference group, PCRE was not
683        taking into account the duplicate group numbers. A pattern such as
684        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
686    26. Changed a few more instances of "const unsigned char *" to USPTR, making
687        the feature of a custom pointer more persuasive (as requested by a user).
689    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
690        pcretest.c, inside #ifndefs, because it seems they are sometimes already
691        pre-defined.
693    28. Added support for (*UTF8) at the start of a pattern.
695    29. Arrange for flags added by the "release type" setting in CMake to be shown
696        in the configuration summary.
699    Version 7.8 05-Sep-08
700    ---------------------
702    1.  Replaced UCP searching code with optimized version as implemented for Ad
703        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
704        stage table and inline lookup instead of a function, giving speed ups of 2
705        to 5 times on some simple patterns that I tested. Permission was given to
706        distribute the MultiStage2.py script that generates the tables (it's not in
707        the tarball, but is in the Subversion repository).
709    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
710        scripts.
712    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
713        a group with a zero qualifier. The result of the study could be incorrect,
714        or the function might crash, depending on the pattern.
716    4.  Caseless matching was not working for non-ASCII characters in back
717        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
718        It now works when Unicode Property Support is available.
720    5.  In pcretest, an escape such as \x{de} in the data was always generating
721        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
722        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
723        truncation.
725    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
727    7.  Added two (int) casts to pcregrep when printing the difference of two
728        pointers, in case they are 64-bit values.
730    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
731        test 2 if it fails.
733    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
734        and a #define of that name to empty if it is not externally set. This is to
735        allow users of MSVC to set it if necessary.
737    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
738        the convenience functions in the pcre_get.c source file.
740    11. An option change at the start of a pattern that had top-level alternatives
741        could cause overwriting and/or a crash. This command provoked a crash in
742        some environments:
744          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
746        This potential security problem was recorded as CVE-2008-2371.
748    12. For a pattern where the match had to start at the beginning or immediately
749        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
750        pcre_dfa_exec() could read past the end of the passed subject if there was
751        no match. To help with detecting such bugs (e.g. with valgrind), I modified
752        pcretest so that it places the subject at the end of its malloc-ed buffer.
754    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
755        exec() might read past the end of the data buffer in UTF-8 mode.
757    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
758        the data contained the byte 0x85 as part of a UTF-8 character within its
759        first line. This applied both to normal and DFA matching.
761    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
762        /^[^d]*?$/8 failed to match "abc".
764    16. Added a missing copyright notice to pcrecpp_internal.h.
766    17. Make it more clear in the documentation that values returned from
767        pcre_exec() in ovector are byte offsets, not character counts.
769    18. Tidied a few places to stop certain compilers from issuing warnings.
771    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
772        supplied by Stefan Weber. I made a further small update for 7.8 because
773        there is a change of source arrangements: the pcre_searchfuncs.c module is
774        replaced by pcre_ucd.c.
777    Version 7.7 07-May-08
778    ---------------------
780    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
781        a string to a long long, pretend we don't even have a long long." This is
782        done by checking for the strtoq, strtoll, and _strtoi64 functions.
784    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
785        pre-7.6 versions, which defined a global no_arg variable instead of putting
786        it in the RE class. (See also #8 below.)
788    3.  Remove a line of dead code, identified by coverity and reported by Nuno
789        Lopes.
791    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
793        (1) The include/exclude patterns were being applied to the whole pathnames
794            of files, instead of just to the final components.
796        (2) If there was more than one level of directory, the subdirectories were
797            skipped unless they satisfied the include/exclude conditions. This is
798            inconsistent with GNU grep (and could even be seen as contrary to the
799            pcregrep specification - which I improved to make it absolutely clear).
800            The action now is always to scan all levels of directory, and just
801            apply the include/exclude patterns to regular files.
803    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
804        --exclude_dir in the tests to avoid scanning .svn directories.
806    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
807        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
808        doesn't support NULs in patterns.
810    7.  Added some missing "const"s to declarations of static tables in
811        pcre_compile.c and pcre_dfa_exec.c.
813    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
814        caused by fix #2  above. (Subsequently also a second patch to fix the
815        first patch. And a third patch - this was a messy problem.)
817    9.  Applied Craig's patch to remove the use of push_back().
819    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
820        matching function regexec().
822    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
823        which, however, unlike Perl's \g{...}, are subroutine calls, not back
824        references. PCRE supports relative numbers with this syntax (I don't think
825        Oniguruma does).
827    12. Previously, a group with a zero repeat such as (...){0} was completely
828        omitted from the compiled regex. However, this means that if the group
829        was called as a subroutine from elsewhere in the pattern, things went wrong
830        (an internal error was given). Such groups are now left in the compiled
831        pattern, with a new opcode that causes them to be skipped at execution
832        time.
834    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
835        to the way PCRE behaves:
837        (a) A lone ] character is dis-allowed (Perl treats it as data).
839        (b) A back reference to an unmatched subpattern matches an empty string
840            (Perl fails the current match path).
842        (c) A data ] in a character class must be notated as \] because if the
843            first data character in a class is ], it defines an empty class. (In
844            Perl it is not possible to have an empty class.) The empty class []
845            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
846            The negative empty class [^] matches any one character, independently
847            of the DOTALL setting.
849    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
850        non-existent subpattern following a character class starting with ']' and
851        containing () gave an internal compiling error instead of "reference to
852        non-existent subpattern". Fortunately, when the pattern did exist, the
853        compiled code was correct. (When scanning forwards to check for the
854        existencd of the subpattern, it was treating the data ']' as terminating
855        the class, so got the count wrong. When actually compiling, the reference
856        was subsequently set up correctly.)
858    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
859        it was being rejected as not supported by pcre_dfa_exec(), even though
860        other assertions are supported. I have made pcre_dfa_exec() support
861        (*FAIL).
863    16. The implementation of 13c above involved the invention of a new opcode,
864        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
865        cannot be changed at match time, I realized I could make a small
866        improvement to matching performance by compiling OP_ALLANY instead of
867        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
868        on the OP_ANY path.
870    17. Compiling pcretest on Windows with readline support failed without the
871        following two fixes: (1) Make the unistd.h include conditional on
872        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
874    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
875        ncurses library to be included for pcretest when ReadLine support is
876        requested, but also to allow for it to be overridden. This patch came from
877        Daniel Bergström.
879    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
880        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
881        any errors with the current Unicode tables. Thanks to Peter Kankowski for
882        spotting this.
885    Version 7.6 28-Jan-08
886    ---------------------
888    1.  A character class containing a very large number of characters with
889        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
890        overflow.
892    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
893        HAVE_LONG_LONG is not defined.
895    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
896        bring them up to date and include new features. This patch includes:
898        - Fixed PH's badly added libz and libbz2 support.
899        - Fixed a problem with static linking.
900        - Added pcredemo. [But later removed - see 7 below.]
901        - Fixed dftables problem and added an option.
902        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
903            HAVE_LONG_LONG.
904        - Added readline support for pcretest.
905        - Added an listing of the option settings after cmake has run.
907    4.  A user submitted a patch to Makefile that makes it easy to create
908        "pcre.dll" under mingw when using Configure/Make. I added stuff to
909        Makefile.am that cause it to include this special target, without
910        affecting anything else. Note that the same mingw target plus all
911        the other distribution libraries and programs are now supported
912        when configuring with CMake (see 6 below) instead of with
913        Configure/Make.
915    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
916        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
917        exported in the Windows port". It has not yet been confirmed that the patch
918        solves the problem, but it does no harm.
920    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
921        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
922        with CMake, and also correct the comment about stack recursion.
924    7.  Remove the automatic building of pcredemo from the ./configure system and
925        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
926        of a program that users should build themselves after PCRE is installed, so
927        building it automatically is not really right. What is more, it gave
928        trouble in some build environments.
930    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
933    Version 7.5 10-Jan-08
934    ---------------------
936    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
937        values in parens when parsing an RE using the C++ wrapper."
939    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
940        Characters greater than 255 were excluded from the class instead of being
941        included.
943    3.  The same bug as (2) above applied to negated POSIX classes such as
944        [:^space:].
946    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
947        defined or documented. It seems to have been a typo for PCRE_STATIC, so
948        I have changed it.
950    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
951        first named subpattern) and a construct such as (?&a) would reference the
952        first named subpattern whose name started with "a" (in other words, the
953        length check was missing). Both these problems are fixed. "Subpattern name
954        expected" is now given for (?&) (a zero-length name), and this patch also
955        makes it give the same error for \k'' (previously it complained that that
956        was a reference to a non-existent subpattern).
958    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
959        this is right because (?- can be followed by option settings as well as by
960        digits. I have, however, made the messages clearer.
962    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
963        than the number used in the conditional) now cause a compile-time error.
964        This is actually not compatible with Perl, which accepts such patterns, but
965        treats the conditional as always being FALSE (as PCRE used to), but it
966        seems to me that giving a diagnostic is better.
968    8.  Change "alphameric" to the more common word "alphanumeric" in comments
969        and messages.
971    9.  Fix two occurrences of "backslash" in comments that should have been
972        "backspace".
974    10. Remove two redundant lines of code that can never be obeyed (their function
975        was moved elsewhere).
977    11. The program that makes PCRE's Unicode character property table had a bug
978        which caused it to generate incorrect table entries for sequences of
979        characters that have the same character type, but are in different scripts.
980        It amalgamated them into a single range, with the script of the first of
981        them. In other words, some characters were in the wrong script. There were
982        thirteen such cases, affecting characters in the following ranges:
984          U+002b0 - U+002c1
985          U+0060c - U+0060d
986          U+0061e - U+00612
987          U+0064b - U+0065e
988          U+0074d - U+0076d
989          U+01800 - U+01805
990          U+01d00 - U+01d77
991          U+01d9b - U+01dbf
992          U+0200b - U+0200f
993          U+030fc - U+030fe
994          U+03260 - U+0327f
995          U+0fb46 - U+0fbb1
996          U+10450 - U+1049d
998    12. The -o option (show only the matching part of a line) for pcregrep was not
999        compatible with GNU grep in that, if there was more than one match in a
1000        line, it showed only the first of them. It now behaves in the same way as
1001        GNU grep.
1003    13. If the -o and -v options were combined for pcregrep, it printed a blank
1004        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1005        does the same. The return code can be used to tell if there were any
1006        non-matching lines.
1008    14. Added --file-offsets and --line-offsets to pcregrep.
1010    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1011        infinitely looping recursion. The bug was that positive lookaheads were not
1012        being skipped when checking for a possible empty match (negative lookaheads
1013        and both kinds of lookbehind were skipped).
1015    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1016        inclusion of <windows.h> to before rather than after the definition of
1017        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1019    17. Specifying a possessive quantifier with a specific limit for a Unicode
1020        character property caused pcre_compile() to compile bad code, which led at
1021        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1022        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1023        caused the error; without that there was no problem.
1025    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1027    19. Added --enable-pcretest-libreadline.
1029    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1030        RE::GlobalReplace(). As a result, the number of replacements returned was
1031        double what it should be. I removed one of the increments, but Craig sent a
1032        later patch that removed the other one (the right fix) and added unit tests
1033        that check the return values (which was not done before).
1035    21. Several CMake things:
1037        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1038            the names libpcre and libpcreposix, not just pcre and pcreposix.
1040        (2) The above change means that pcretest and pcregrep are now correctly
1041            linked with the newly-built libraries, not previously installed ones.
1045    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1046        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1047        UTF-8 newline character). The key issue is that the pattern starts .*;
1048        this means that the match must be either at the beginning, or after a
1049        newline. The bug was in the code for advancing after a failed match and
1050        checking that the new position followed a newline. It was not taking
1051        account of UTF-8 characters correctly.
1053    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1054        character classes. PCRE was not treating the sequence [:...:] as a
1055        character class unless the ... were all letters. Perl, however, seems to
1056        allow any characters between [: and :], though of course it rejects as
1057        unknown any "names" that contain non-letters, because all the known class
1058        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1059        for example, whereas PCRE did not - it did not recognize a POSIX character
1060        class. This seemed a bit dangerous, so the code has been changed to be
1061        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1062        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1063        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1064        Perl does, and where it didn't before.
1066    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1067        Windows environments %n is disabled by default.
1070    Version 7.4 21-Sep-07
1071    ---------------------
1073    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1074        means that a class such as [\s] counted as "explicit reference to CR or
1075        LF". That isn't really right - the whole point of the change was to try to
1076        help when there was an actual mention of one of the two characters. So now
1077        the change happens only if \r or \n (or a literal CR or LF) character is
1078        encountered.
1080    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1081        of both had grown to the point where there were only 3 bits left.
1082        Fortunately, there was spare space in the data structure, and so I have
1083        moved the internal flags into a new 16-bit field to free up more option
1084        bits.
1086    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1087        but did not set the internal JCHANGED flag - either of these is enough to
1088        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1089        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1090        start sets both bits.
1092    4.  Added options (at build time, compile time, exec time) to change \R from
1093        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1095    5.  doc/pcresyntax.html was missing from the distribution.
1097    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1098        compatibility, even though it is no longer used.
1100    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1101        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1102        windows.h file is present (where different names are used). [This was
1103        reversed later after testing - see 16 below.]
1105    8.  Changed all #include <config.h> to #include "config.h". There were also
1106        some further <pcre.h> cases that I changed to "pcre.h".
1108    9.  When pcregrep was used with the --colour option, it missed the line ending
1109        sequence off the lines that it output.
1111    10. It was pointed out to me that arrays of string pointers cause lots of
1112        relocations when a shared library is dynamically loaded. A technique of
1113        using a single long string with a table of offsets can drastically reduce
1114        these. I have refactored PCRE in four places to do this. The result is
1115        dramatic:
1117          Originally:                          290
1118          After changing UCP table:            187
1119          After changing error message table:   43
1120          After changing table of "verbs"       36
1121          After changing table of Posix names   22
1123        Thanks to the folks working on Gregex for glib for this insight.
1125    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1126        unicode-properties was also set.
1128    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1130    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1131        checked only for CRLF.
1133    14. Added casts to pcretest.c to avoid compiler warnings.
1135    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1137    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1138        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1139        entirely. This removes changes made in 7 above.
1141    17. The CMake files have been updated, and there is now more information about
1142        building with CMake in the NON-UNIX-USE document.
1145    Version 7.3 28-Aug-07
1146    ---------------------
1148     1. In the rejigging of the build system that eventually resulted in 7.1, the
1149        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1150        brackets there is not right, since it causes compilers to look for an
1151        installed pcre.h, not the version that is in the source that is being
1152        compiled (which of course may be different). I have changed it back to:
1154          #include "pcre.h"
1156        I have a vague recollection that the change was concerned with compiling in
1157        different directories, but in the new build system, that is taken care of
1158        by the VPATH setting the Makefile.
1160     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1161        when the subject happened to end in the byte 0x85 (e.g. if the last
1162        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1163        characters but of course it shouldn't be taken as a newline when it is part
1164        of another character. The bug was that, for an unlimited repeat of . in
1165        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1166        characters when looking for a newline.
1168     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1170     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1171        in debug output.
1173     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1174        long printing in the pcrecpp unittest when running under MinGW.
1176     6. ESC_K was left out of the EBCDIC table.
1178     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1179        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1180        limit also applies to "virtual nesting" when a pattern is recursive, and in
1181        this case 1000 isn't so big. I have been able to remove this limit at the
1182        expense of backing off one optimization in certain circumstances. Normally,
1183        when pcre_exec() would call its internal match() function recursively and
1184        immediately return the result unconditionally, it uses a "tail recursion"
1185        feature to save stack. However, when a subpattern that can match an empty
1186        string has an unlimited repetition quantifier, it no longer makes this
1187        optimization. That gives it a stack frame in which to save the data for
1188        checking that an empty string has been matched. Previously this was taken
1189        from the 1000-entry workspace that had been reserved. So now there is no
1190        explicit limit, but more stack is used.
1192     8. Applied Daniel's patches to solve problems with the import/export magic
1193        syntax that is required for Windows, and which was going wrong for the
1194        pcreposix and pcrecpp parts of the library. These were overlooked when this
1195        problem was solved for the main library.
1197     9. There were some crude static tests to avoid integer overflow when computing
1198        the size of patterns that contain repeated groups with explicit upper
1199        limits. As the maximum quantifier is 65535, the maximum group length was
1200        set at 30,000 so that the product of these two numbers did not overflow a
1201        32-bit integer. However, it turns out that people want to use groups that
1202        are longer than 30,000 bytes (though not repeat them that many times).
1203        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1204        made it possible to implement the integer overflow checks in a much more
1205        dynamic way, which I have now done. The artificial limitation on group
1206        length has been removed - we now have only the limit on the total length of
1207        the compiled pattern, which depends on the LINK_SIZE setting.
1209    10. Fixed a bug in the documentation for get/copy named substring when
1210        duplicate names are permitted. If none of the named substrings are set, the
1211        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1212        empty string.
1214    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1215        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1216        because the ] is interpreted as the first data character and the
1217        terminating ] is not found. PCRE has been made compatible with Perl in this
1218        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1219        cause memory overwriting.
1221    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1222        string has been matched (to stop an infinite loop). It was not recognizing
1223        a conditional subpattern that could match an empty string if that
1224        subpattern was within another subpattern. For example, it looped when
1225        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1226        condition was not nested. This bug has been fixed.
1228    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1229        past the start of the subject in the presence of bytes with the top bit
1230        set, for example "\x8aBCD".
1232    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1233        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1235    14. Optimized (?!) to (*FAIL).
1237    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1238        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1239        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1240        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1241        does: it's just the validity check that is more restrictive.
1243    16. Inserted checks for integer overflows during escape sequence (backslash)
1244        processing, and also fixed erroneous offset values for syntax errors during
1245        backslash processing.
1247    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1248        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1250    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1251        caused an overrun.
1253    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1254        something other than just ASCII characters) inside a group that had an
1255        unlimited repeat caused a loop at compile time (while checking to see
1256        whether the group could match an empty string).
1258    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1259        [\P{Any}] did so. (Error in the code for printing property names.)
1261    21. An orphan \E inside a character class could cause a crash.
1263    22. A repeated capturing bracket such as (A)? could cause a wild memory
1264        reference during compilation.
1266    23. There are several functions in pcre_compile() that scan along a compiled
1267        expression for various reasons (e.g. to see if it's fixed length for look
1268        behind). There were bugs in these functions when a repeated \p or \P was
1269        present in the pattern. These operators have additional parameters compared
1270        with \d, etc, and these were not being taken into account when moving along
1271        the compiled data. Specifically:
1273        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1274            length.
1276        (b) An item such as \pL+ within a repeated group could cause crashes or
1277            loops.
1279        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1280            "reference to non-existent subpattern" error.
1282        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1284    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1285        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1287    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1289    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1290        character were causing crashes (broken optimization).
1292    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1293        \p or \P) caused a compile-time loop.
1295    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1296        break. For example, the unstudied pattern [\r\n]A does not match the string
1297        "\r\nA" because change 7.0/46 below moves the current point on by two
1298        characters after failing to match at the start. However, the pattern \nA
1299        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1300        the same is true. There doesn't seem any very clean way out of this, but
1301        what I have chosen to do makes the common cases work: PCRE now takes note
1302        of whether there can be an explicit match for \r or \n anywhere in the
1303        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1304        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1305        pattern has explicit CR or LF references.
1307    29. Added (*CR) etc for changing newline setting at start of pattern.
1310    Version 7.2 19-Jun-07
1311    ---------------------
1313     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1314        which is apparently normally available under Windows.
1316     2. Re-jig the pcregrep tests with different newline settings in an attempt
1317        to make them independent of the local environment's newline setting.
1319     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1321     4. Some of the "internals" tests were previously cut out when the link size
1322        was not 2, because the output contained actual offsets. The recent new
1323        "Z" feature of pcretest means that these can be cut out, making the tests
1324        usable with all link sizes.
1326     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1327        stack recursion. This gives a massive performance boost under BSD, but just
1328        a small improvement under Linux. However, it saves one field in the frame
1329        in all cases.
1331     6. Added more features from the forthcoming Perl 5.10:
1333        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1334            recursion call. It refers to the nth most recently opened parentheses.
1336        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1337            to be opened parentheses.
1339        (c) Conditions that refer to capturing parentheses can be specified
1340            relatively, for example, (?(-2)... or (?(+3)...
1342        (d) \K resets the start of the current match so that everything before
1343            is not part of it.
1345        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1347        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1348            reference syntax.
1350        (g) (?| introduces a group in which the numbering of parentheses in each
1351            alternative starts with the same number.
1353        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1355     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1358     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1359        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1360        for detecting groups that can match an empty string.
1362     9. A pattern with a very large number of alternatives (more than several
1363        hundred) was running out of internal workspace during the pre-compile
1364        phase, where pcre_compile() figures out how much memory will be needed. A
1365        bit of new cunning has reduced the workspace needed for groups with
1366        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1367        workspace instead of running out of the 4096 that are available.
1369    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1371    11. Applied patch from Google to remove an optimization that didn't quite work.
1372        The report of the bug said:
1374          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1375          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1376          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1378    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1379        it matched the wrong number of bytes.
1382    Version 7.1 24-Apr-07
1383    ---------------------
1385     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1386        that is more "standard", making use of automake and other Autotools. There
1387        is some re-arrangement of the files and adjustment of comments consequent
1388        on this.
1390     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1391        for recursive directory scanning broke on some systems because the files
1392        are not scanned in any specific order and on different systems the order
1393        was different. A call to "sort" has been inserted into RunGrepTest for the
1394        approprate test as a short-term fix. In the longer term there may be an
1395        alternative.
1397     3. I had an email from Eric Raymond about problems translating some of PCRE's
1398        man pages to HTML (despite the fact that I distribute HTML pages, some
1399        people do their own conversions for various reasons). The problems
1400        concerned the use of low-level troff macros .br and .in. I have therefore
1401        removed all such uses from the man pages (some were redundant, some could
1402        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1403        HTML has been updated to handle .nf/.fi and to complain if it encounters
1404        .br or .in.
1406     4. Updated comments in configure.ac that get placed in config.h.in and also
1407        arranged for config.h to be included in the distribution, with the name
1408        config.h.generic, for the benefit of those who have to compile without
1409        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1411     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1412        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1413        makevp.bat for the current PCRE, using the additional files
1414        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1416     6. A Windows user reported a minor discrepancy with test 2, which turned out
1417        to be caused by a trailing space on an input line that had got lost in his
1418        copy. The trailing space was an accident, so I've just removed it.
1420     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1421        that is needed.
1423     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1424        as "const" (a) because they are and (b) because it helps the PHP
1425        maintainers who have recently made a script to detect big data structures
1426        in the php code that should be moved to the .rodata section. I remembered
1427        to update Builducptable as well, so it won't revert if ucptable.h is ever
1428        re-created.
1430     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1431        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1432        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1433        support is not required. This saves 1.5-2K of code, which is important in
1434        some applications.
1436        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1437        so as not to refer to the tables, even though these functions will never be
1438        called when UTF-8 support is disabled. Otherwise there are problems with a
1439        shared library.
1441    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1443        (a) It was defining its arguments as char * instead of void *.
1445        (b) It was assuming that all moves were upwards in memory; this was true
1446            a long time ago when I wrote it, but is no longer the case.
1448        The emulated memove() is provided for those environments that have neither
1449        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1450        is clearly not the case, as these two bugs were recently reported.
1452    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1453        and Detrail to create the HTML documentation, the .txt form of the man
1454        pages, and it removes trailing spaces from listed files. It also creates
1455        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1456        case, it wraps all the #defines with #ifndefs. This script should be run
1457        before "make dist".
1459    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1460        with Unicode property support.
1462        (a) For a maximizing quantifier, if the two different cases of the
1463            character were of different lengths in their UTF-8 codings (there are
1464            some cases like this - I found 11), and the matching function had to
1465            back up over a mixture of the two cases, it incorrectly assumed they
1466            were both the same length.
1468        (b) When PCRE was configured to use the heap rather than the stack for
1469            recursion during matching, it was not correctly preserving the data for
1470            the other case of a UTF-8 character when checking ahead for a match
1471            while processing a minimizing repeat. If the check also involved
1472            matching a wide character, but failed, corruption could cause an
1473            erroneous result when trying to check for a repeat of the original
1474            character.
1476    13. Some tidying changes to the testing mechanism:
1478        (a) The RunTest script now detects the internal link size and whether there
1479            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1480            values substituted by "configure". (The RunGrepTest script already did
1481            this for UTF-8.) The configure.ac script no longer substitutes the
1482            relevant variables.
1484        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1485            with length and offset values. This means that the output is different
1486            for different internal link sizes. Test 2 is skipped for link sizes
1487            other than 2 because of this, bypassing the problem. Unfortunately,
1488            there was also a test in test 3 (the locale tests) that used /B and
1489            failed for link sizes other than 2. Rather than cut the whole test out,
1490            I have added a new /Z option to pcretest that replaces the length and
1491            offset values with spaces. This is now used to make test 3 independent
1492            of link size. (Test 2 will be tidied up later.)
1494    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1495        segmentation fault instead of returning the appropriate error message.
1497    15. In multiline mode when the newline sequence was set to "any", the pattern
1498        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1499        This doesn't seem right; it now treats the CRLF combination as the line
1500        ending, and so does not match in that case. It's only a pattern such as ^$
1501        that would hit this one: something like ^ABC$ would have failed after \r
1502        and then tried again after \r\n.
1504    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1505        in an attempt to make files that differ only in their line terminators
1506        compare equal. This works on Linux.
1508    17. Under certain error circumstances pcregrep might try to free random memory
1509        as it exited. This is now fixed, thanks to valgrind.
1511    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1512        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1513        was because its rules for how to advance for /g after matching an empty
1514        string at the end of a line did not allow for this case. They now check for
1515        it specially.
1517    20. pcretest is supposed to handle patterns and data of any length, by
1518        extending its buffers when necessary. It was getting this wrong when the
1519        buffer for a data line had to be extended.
1521    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1522        CRLF as a newline sequence.
1524    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1525        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1526        I have nevertheless tidied it up.
1528    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1530    24. Added a man page for pcre-config.
1533    Version 7.0 19-Dec-06
1534    ---------------------
1536     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1537        moving to gcc 4.1.1.
1539     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1540        sys/time.h, which is documented as needed for this function. It doesn't
1541        seem to matter on Linux, but it showed up on some releases of OS X.
1543     3. It seems that there are systems where bytes whose values are greater than
1544        127 match isprint() in the "C" locale. The "C" locale should be the
1545        default when a C program starts up. In most systems, only ASCII printing
1546        characters match isprint(). This difference caused the output from pcretest
1547        to vary, making some of the tests fail. I have changed pcretest so that:
1549        (a) When it is outputting text in the compiled version of a pattern, bytes
1550            other than 32-126 are always shown as hex escapes.
1552        (b) When it is outputting text that is a matched part of a subject string,
1553            it does the same, unless a different locale has been set for the match
1554            (using the /L modifier). In this case, it uses isprint() to decide.
1556     4. Fixed a major bug that caused incorrect computation of the amount of memory
1557        required for a compiled pattern when options that changed within the
1558        pattern affected the logic of the preliminary scan that determines the
1559        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1560        that the computed length was too small. The symptoms of this bug were
1561        either the PCRE error "internal error: code overflow" from pcre_compile(),
1562        or a glibc crash with a message such as "pcretest: free(): invalid next
1563        size (fast)". Examples of patterns that provoked this bug (shown in
1564        pcretest format) are:
1566          /(?-x: )/x
1567          /(?x)(?-x: \s*#\s*)/
1568          /((?i)[\x{c0}])/8
1569          /(?i:[\x{c0}])/8
1571        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1572        is now done differently.
1574     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1575        wrapper classes; (b) implement a new function in the C++ scanner that is
1576        more efficient than the old way of doing things because it avoids levels of
1577        recursion in the regex matching; (c) add a paragraph to the documentation
1578        for the FullMatch() function.
1580     6. The escape sequence \n was being treated as whatever was defined as
1581        "newline". Not only was this contrary to the documentation, which states
1582        that \n is character 10 (hex 0A), but it also went horribly wrong when
1583        "newline" was defined as CRLF. This has been fixed.
1585     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1586        was being set to -1 for the "end of line" case (supposedly a value that no
1587        character can have). Though this value is never used (the check for end of
1588        line is "zero bytes in current character"), it caused compiler complaints.
1589        I've changed it to 0xffffffff.
1591     8. In pcre_version.c, the version string was being built by a sequence of
1592        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1593        string (as it is for production releases) called a macro with an empty
1594        argument. The C standard says the result of this is undefined. The gcc
1595        compiler treats it as an empty string (which was what was wanted) but it is
1596        reported that Visual C gives an error. The source has been hacked around to
1597        avoid this problem.
1599     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1600        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1601        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1602        of them did).
1604    10. Originally, pcretest opened its input and output without "b"; then I was
1605        told that "b" was needed in some environments, so it was added for release
1606        5.0 to both the input and output. (It makes no difference on Unix-like
1607        systems.) Later I was told that it is wrong for the input on Windows. I've
1608        now abstracted the modes into two macros, to make it easier to fiddle with
1609        them, and removed "b" from the input mode under Windows.
1611    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1613    12. Added -help and --help to pcretest as an official way of being reminded
1614        of the options.
1616    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1617        and pcrecpp.cc because they annoy compilers at high warning levels.
1619    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1621    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1622        scripts are not C programs :-) and which was not noticed because it works
1623        on Linux.
1625    16. pcretest is supposed to handle any length of pattern and data line (as one
1626        line or as a continued sequence of lines) by extending its input buffer if
1627        necessary. This feature was broken for very long pattern lines, leading to
1628        a string of junk being passed to pcre_compile() if the pattern was longer
1629        than about 50K.
1631    17. I have done a major re-factoring of the way pcre_compile() computes the
1632        amount of memory needed for a compiled pattern. Previously, there was code
1633        that made a preliminary scan of the pattern in order to do this. That was
1634        OK when PCRE was new, but as the facilities have expanded, it has become
1635        harder and harder to keep it in step with the real compile phase, and there
1636        have been a number of bugs (see for example, 4 above). I have now found a
1637        cunning way of running the real compile function in a "fake" mode that
1638        enables it to compute how much memory it would need, while actually only
1639        ever using a few hundred bytes of working memory and without too many
1640        tests of the mode. This should make future maintenance and development
1641        easier. A side effect of this work is that the limit of 200 on the nesting
1642        depth of parentheses has been removed (though this was never a serious
1643        limitation, I suspect). However, there is a downside: pcre_compile() now
1644        runs more slowly than before (30% or more, depending on the pattern). I
1645        hope this isn't a big issue. There is no effect on runtime performance.
1647    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1648        newline (only possible for the last line of a file) and it was a
1649        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1651    19. Added additional timing features to pcretest. (1) The -tm option now times
1652        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1653        separate command line item, by a number that specifies the number of
1654        repeats to use when timing. The default is 50000; this gives better
1655        precision, but takes uncomfortably long for very large patterns.
1657    20. Extended pcre_study() to be more clever in cases where a branch of a
1658        subpattern has no definite first character. For example, (a*|b*)[cd] would
1659        previously give no result from pcre_study(). Now it recognizes that the
1660        first character must be a, b, c, or d.
1662    21. There was an incorrect error "recursive call could loop indefinitely" if
1663        a subpattern (or the entire pattern) that was being tested for matching an
1664        empty string contained only one non-empty item after a nested subpattern.
1665        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1666        incorrectly, because the \d was being skipped in the check.
1668    22. The pcretest program now has a new pattern option /B and a command line
1669        option -b, which is equivalent to adding /B to every pattern. This causes
1670        it to show the compiled bytecode, without the additional information that
1671        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1672        is the same as /B/I).
1674    23. A new optimization is now able automatically to treat some sequences such
1675        as a*b as a*+b. More specifically, if something simple (such as a character
1676        or a simple class like \d) has an unlimited quantifier, and is followed by
1677        something that cannot possibly match the quantified thing, the quantifier
1678        is automatically "possessified".
1680    24. A recursive reference to a subpattern whose number was greater than 39
1681        went wrong under certain circumstances in UTF-8 mode. This bug could also
1682        have affected the operation of pcre_study().
1684    25. Realized that a little bit of performance could be had by replacing
1685        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1687    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1689    27. Possessive quantifiers such as a++ were previously implemented by turning
1690        them into atomic groups such as ($>a+). Now they have their own opcodes,
1691        which improves performance. This includes the automatically created ones
1692        from 23 above.
1694    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1695        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1696        the first matched character to be a colon. This applied both to named and
1697        numbered groups.
1699    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1701    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1702        building PCRE on Windows easier, so I have included it in the distribution.
1704    31. There is now a check in pcretest against a ridiculously large number being
1705        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1706        loop, the loop is abandoned.
1708    32. Forward references to subpatterns in conditions such as (?(2)...) where
1709        subpattern 2 is defined later cause pcre_compile() to search forwards in
1710        the pattern for the relevant set of parentheses. This search went wrong
1711        when there were unescaped parentheses in a character class, parentheses
1712        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1714    33. "Subroutine" calls and backreferences were previously restricted to
1715        referencing subpatterns earlier in the regex. This restriction has now
1716        been removed.
1718    34. Added a number of extra features that are going to be in Perl 5.10. On the
1719        whole, these are just syntactic alternatives for features that PCRE had
1720        previously implemented using the Python syntax or my own invention. The
1721        other formats are all retained for compatibility.
1723        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1724            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1725            also .NET compatible.
1727        (b) A recursion or subroutine call to a named group can now be defined as
1728            (?&name) as well as (?P>name).
1730        (c) A backreference to a named group can now be defined as \k<name> or
1731            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1732            5.10, are also .NET compatible.
1734        (d) A conditional reference to a named group can now use the syntax
1735            (?(<name>) or (?('name') as well as (?(name).
1737        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1738            groups (named and numbered) that are never evaluated inline, but can be
1739            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1740            is always false. There may be only one alternative in such a group.
1742        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1743            as the simple (?(R). The condition is true only if the most recent
1744            recursion is that of the given number or name. It does not search out
1745            through the entire recursion stack.
1747        (g) The escape \gN or \g{N} has been added, where N is a positive or
1748            negative number, specifying an absolute or relative reference.
1750    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1751        some "unreachable code" warnings.
1753    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1754        things, this adds five new scripts.
1756    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1757        There were also incompatibilities regarding the handling of \Q..\E inside
1758        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1759        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1761    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1762        matches an empty string, and forcibly breaks the loop. There were bugs in
1763        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1764        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1765        separate and independent bugs (that affected different cases) have been
1766        fixed.
1768    39. Refactored the code to abolish the use of different opcodes for small
1769        capturing bracket numbers. This is a tidy that I avoided doing when I
1770        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1771        The new approach is not only tidier, it makes it possible to reduce the
1772        memory needed to fix the previous bug (38).
1774    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1775        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1776        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1777        mode.
1779    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1780        report.
1782    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1783        copy construction and assignment in the C++ wrapper.
1785    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1786        couple of bugs that could have given wrong results in the "--newline=crlf"
1787        case.
1789    44. Added a number of casts and did some reorganization of signed/unsigned int
1790        variables following suggestions from Dair Grant. Also renamed the variable
1791        "this" as "item" because it is a C++ keyword.
1793    45. Arranged for dftables to add
1795          #include "pcre_internal.h"
1797        to pcre_chartables.c because without it, gcc 4.x may remove the array
1798        definition from the final binary if PCRE is built into a static library and
1799        dead code stripping is activated.
1801    46. For an unanchored pattern, if a match attempt fails at the start of a
1802        newline sequence, and the newline setting is CRLF or ANY, and the next two
1803        characters are CRLF, advance by two characters instead of one.
1806    Version 6.7 04-Jul-06
1807    ---------------------
1809     1. In order to handle tests when input lines are enormously long, pcretest has
1810        been re-factored so that it automatically extends its buffers when
1811        necessary. The code is crude, but this _is_ just a test program. The
1812        default size has been increased from 32K to 50K.
1814     2. The code in pcre_study() was using the value of the re argument before
1815        testing it for NULL. (Of course, in any sensible call of the function, it
1816        won't be NULL.)
1818     3. The memmove() emulation function in pcre_internal.h, which is used on
1819        systems that lack both memmove() and bcopy() - that is, hardly ever -
1820        was missing a "static" storage class specifier.
1822     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1823        containing an extended class (one that cannot be represented by a bitmap
1824        because it contains high-valued characters or Unicode property items, e.g.
1825        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1826        pattern, but PCRE should not loop if you do not (it no longer does).
1827        [Detail: two cases were found: (a) a repeated subpattern containing an
1828        extended class; (b) a recursive reference to a subpattern that followed a
1829        previous extended class. It wasn't skipping over the extended class
1830        correctly when UTF-8 mode was not set.]
1832     5. A negated single-character class was not being recognized as fixed-length
1833        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1834        compile error "lookbehind assertion is not fixed length".
1836     6. The RunPerlTest auxiliary script was showing an unexpected difference
1837        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1838        write a Perl script that can interpret lines of an input file either as
1839        byte characters or as UTF-8, which is what "perltest" was being required to
1840        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1841        can't do is switch easily at run time between having the "use utf8;" pragma
1842        or not. In the end, I fudged it by using the RunPerlTest script to insert
1843        "use utf8;" explicitly for the UTF-8 tests.
1845     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1846        the end of the subject string, contrary to the documentation and to what
1847        Perl does. This was true of both matching functions. Now it matches only at
1848        the start of the subject and immediately after *internal* newlines.
1850     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1851        a pointer to an int instead of a pointer to an unsigned long int. This
1852        caused problems on 64-bit systems.
1854     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1855        instance of the 'standard' template library not being so standard".
1857    10. There was no check on the number of named subpatterns nor the maximum
1858        length of a subpattern name. The product of these values is used to compute
1859        the size of the memory block for a compiled pattern. By supplying a very
1860        long subpattern name and a large number of named subpatterns, the size
1861        computation could be caused to overflow. This is now prevented by limiting
1862        the length of names to 32 characters, and the number of named subpatterns
1863        to 10,000.
1865    11. Subpatterns that are repeated with specific counts have to be replicated in
1866        the compiled pattern. The size of memory for this was computed from the
1867        length of the subpattern and the repeat count. The latter is limited to
1868        65535, but there was no limit on the former, meaning that integer overflow
1869        could in principle occur. The compiled length of a repeated subpattern is
1870        now limited to 30,000 bytes in order to prevent this.
1872    12. Added the optional facility to have named substrings with the same name.
1874    13. Added the ability to use a named substring as a condition, using the
1875        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1876        are numbers (not recommended). Forward references are permitted.
1878    14. Added forward references in named backreferences (if you see what I mean).
1880    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1881        pattern could run off the end of the subject. For example, the pattern
1882        "(?s)(.{1,5})"8 did this with the subject "ab".
1884    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1885        PCRE_CASELESS was set when matching characters that were quantified with ?
1886        or *.
1888    17. A character class other than a single negated character that had a minimum
1889        but no maximum quantifier - for example [ab]{6,} - was not handled
1890        correctly by pce_dfa_exec(). It would match only one character.
1892    18. A valid (though odd) pattern that looked like a POSIX character
1893        class but used an invalid character after [ (for example [[,abc,]]) caused
1894        pcre_compile() to give the error "Failed: internal error: code overflow" or
1895        in some cases to crash with a glibc free() error. This could even happen if
1896        the pattern terminated after [[ but there just happened to be a sequence of
1897        letters, a binary zero, and a closing ] in the memory that followed.
1899    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1900        over the years. Originally (before any Unicode support), just the bottom 8
1901        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1902        output from "man perlunicode" includes this:
1904          The regular expression compiler produces polymorphic opcodes.  That
1905          is, the pattern adapts to the data and automatically switches to
1906          the Unicode character scheme when presented with Unicode data--or
1907          instead uses a traditional byte scheme when presented with byte
1908          data.
1910        Sadly, a wide octal escape does not cause a switch, and in a string with
1911        no other multibyte characters, these octal escapes are treated as before.
1912        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1913        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1914        Unicode string.
1916        I have not perpetrated such confusion in PCRE. Up till now, it took just
1917        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1918        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1919        translate to the appropriate multibyte character.
1921    29. Applied some refactoring to reduce the number of warnings from Microsoft
1922        and Borland compilers. This has included removing the fudge introduced
1923        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1924        a warning about an unused variable.
1926    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1927        characters since release 4.0, because Perl (from release 5.004) does not.
1928        [Or at least, is documented not to: some releases seem to be in conflict
1929        with the documentation.] However, when a pattern was studied with
1930        pcre_study() and all its branches started with \s, PCRE still included VT
1931        as a possible starting character. Of course, this did no harm; it just
1932        caused an unnecessary match attempt.
1934    22. Removed a now-redundant internal flag bit that recorded the fact that case
1935        dependency changed within the pattern. This was once needed for "required
1936        byte" processing, but is no longer used. This recovers a now-scarce options
1937        bit. Also moved the least significant internal flag bit to the most-
1938        significant bit of the word, which was not previously used (hangover from
1939        the days when it was an int rather than a uint) to free up another bit for
1940        the future.
1942    23. Added support for CRLF line endings as well as CR and LF. As well as the
1943        default being selectable at build time, it can now be changed at runtime
1944        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1945        specify that it is scanning data with non-default line endings.
1947    24. Changed the definition of CXXLINK to make it agree with the definition of
1948        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1950    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1951        recursions. This makes a big different to stack usage for some patterns.
1953    26. If a subpattern containing a named recursion or subroutine reference such
1954        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1955        the space required for the compiled pattern went wrong and gave too small a
1956        value. Depending on the environment, this could lead to "Failed: internal
1957        error: code overflow at offset 49" or "glibc detected double free or
1958        corruption" errors.
1960    27. Applied patches from Google (a) to support the new newline modes and (b) to
1961        advance over multibyte UTF-8 characters in GlobalReplace.
1963    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1964        difference for some implementation of PCRE in some Windows version.
1966    29. Added some extra testing facilities to pcretest:
1968        \q<number>   in a data line sets the "match limit" value
1969        \Q<number>   in a data line sets the "match recursion limt" value
1970        -S <number>  sets the stack size, where <number> is in megabytes
1972        The -S option isn't available for Windows.
1975    Version 6.6 06-Feb-06
1976    ---------------------
1978     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1979        in pcreposix.h. I have copied the definition from pcre.h.
1981     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1982        because pcre.h is no longer a built file.
1984     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1985        not normally included in the compiled code.
1988    Version 6.5 01-Feb-06
1989    ---------------------
1991     1. When using the partial match feature with pcre_dfa_exec(), it was not
1992        anchoring the second and subsequent partial matches at the new starting
1993        point. This could lead to incorrect results. For example, with the pattern
1994        /1234/, partially matching against "123" and then "a4" gave a match.
1996     2. Changes to pcregrep:
1998        (a) All non-match returns from pcre_exec() were being treated as failures
1999            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2000            error message is output. Some extra information is given for the
2001            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2002            probably the only errors that are likely to be caused by users (by
2003            specifying a regex that has nested indefinite repeats, for instance).
2004            If there are more than 20 of these errors, pcregrep is abandoned.
2006        (b) A binary zero was treated as data while matching, but terminated the
2007            output line if it was written out. This has been fixed: binary zeroes
2008            are now no different to any other data bytes.
2010        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2011            used to set a locale for matching. The --locale=xxxx long option has
2012            been added (no short equivalent) to specify a locale explicitly on the
2013            pcregrep command, overriding the environment variables.
2015        (d) When -B was used with -n, some line numbers in the output were one less
2016            than they should have been.
2018        (e) Added the -o (--only-matching) option.
2020        (f) If -A or -C was used with -c (count only), some lines of context were
2021            accidentally printed for the final match.
2023        (g) Added the -H (--with-filename) option.
2025        (h) The combination of options -rh failed to suppress file names for files
2026            that were found from directory arguments.
2028        (i) Added the -D (--devices) and -d (--directories) options.
2030        (j) Added the -F (--fixed-strings) option.
2032        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2034        (l) Added the --colo(u)r option.
2036        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2037            is not present by default.
2039     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2040        items such as (?R) or (?1), when the recursion could match a number of
2041        alternatives. If it matched one of the alternatives, but subsequently,
2042        outside the recursion, there was a failure, the code tried to back up into
2043        the recursion. However, because of the way PCRE is implemented, this is not
2044        possible, and the result was an incorrect result from the match.
2046        In order to prevent this happening, the specification of recursion has
2047        been changed so that all such subpatterns are automatically treated as
2048        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2050     4. I had overlooked the fact that, in some locales, there are characters for
2051        which isalpha() is true but neither isupper() nor islower() are true. In
2052        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2053        and ordfeminine) are like this. This affected the treatment of \w and \W
2054        when they appeared in character classes, but not when they appeared outside
2055        a character class. The bit map for "word" characters is now created
2056        separately from the results of isalnum() instead of just taking it from the
2057        upper, lower, and digit maps. (Plus the underscore character, of course.)
2059     5. The above bug also affected the handling of POSIX character classes such as
2060        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2061        permanent tables. Instead, the bit maps for such a class were previously
2062        created as the appropriate unions of the upper, lower, and digit bitmaps.
2063        Now they are created by subtraction from the [[:word:]] class, which has
2064        its own bitmap.
2066     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2067        It is created by subtracting the vertical space characters (\x09, \x0a,
2068        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2069        subtraction was done in the overall bitmap for a character class, meaning
2070        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2071        be recognized. This bug has been fixed.
2073     7. Patches from the folks at Google:
2075          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2076          real life, but is still worth protecting against".
2078          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2079          regular expressions".
2081          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2082          have it.
2084          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2085          "configure" and the latter not, in order to fix a problem somebody had
2086          with compiling the Arg class on HP-UX.
2088          (e) Improve the error-handling of the C++ wrapper a little bit.
2090          (f) New tests for checking recursion limiting.
2092     8. The pcre_memmove() function, which is used only if the environment does not
2093        have a standard memmove() function (and is therefore rarely compiled),
2094        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2095        returning a result (though PCRE never actually uses the result).
2097     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2098        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2099        returned instead of calling malloc() with an overflowing number that would
2100        most likely cause subsequent chaos.
2102    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2104    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2105        with this option is matched, the nmatch and pmatch options of regexec() are
2106        ignored.
2108    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2109        provided in case anyone wants to the the POSIX interface with UTF-8
2110        strings.
2112    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2113        C++ linking (needed for some HP-UX environments).
2115    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2116        (unused parameter) and in the pcre_printint() function (omitted "default"
2117        switch label when the default is to do nothing).
2119    15. Added some code to make it possible, when PCRE is compiled as a C++
2120        library, to replace subject pointers for pcre_exec() with a smart pointer
2121        class, thus making it possible to process discontinuous strings.
2123    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2124        much the same function. They were added by different people who were trying
2125        to make PCRE easy to compile on non-Unix systems. It has been suggested
2126        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2127        for compiling on Windows systems. I have therefore replaced it with
2128        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2129        defaults to "extern" for C or "extern C" for C++, which works fine on
2130        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2131        SCOPE with something explicit in config.h. In addition:
2133        (a) pcreposix.h still had just "extern" instead of either of these macros;
2134            I have replaced it with PCRE_DATA_SCOPE.
2136        (b) Functions such as _pcre_xclass(), which are internal to the library,
2137            but external in the C sense, all had PCRE_EXPORT in their definitions.
2138            This is apparently wrong for the Windows case, so I have removed it.
2139            (It makes no difference on Unix-like systems.)
2141    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2142        of recursive calls to match(). This is different to MATCH_LIMIT because
2143        that limits the total number of calls to match(), not all of which increase
2144        the depth of recursion. Limiting the recursion depth limits the amount of
2145        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2146        when PCRE is compiled, and changed at run time. A patch from Google adds
2147        this functionality to the C++ interface.
2149    18. Changes to the handling of Unicode character properties:
2151        (a) Updated the table to Unicode 4.1.0.
2153        (b) Recognize characters that are not in the table as "Cn" (undefined).
2155        (c) I revised the way the table is implemented to a much improved format
2156            which includes recognition of ranges. It now supports the ranges that
2157            are defined in UnicodeData.txt, and it also amalgamates other
2158            characters into ranges. This has reduced the number of entries in the
2159            table from around 16,000 to around 3,000, thus reducing its size
2160            considerably. I realized I did not need to use a tree structure after
2161            all - a binary chop search is just as efficient. Having reduced the
2162            number of entries, I extended their size from 6 bytes to 8 bytes to
2163            allow for more data.
2165        (d) Added support for Unicode script names via properties such as \p{Han}.
2167    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2168        matching that character.
2170    20. When matching a repeated Unicode property with a minimum greater than zero,
2171        (for example \pL{2,}), PCRE could look past the end of the subject if it
2172        reached it while seeking the minimum number of characters. This could
2173        happen only if some of the characters were more than one byte long, because
2174        there is a check for at least the minimum number of bytes.
2176    21. Refactored the implementation of \p and \P so as to be more general, to
2177        allow for more different types of property in future. This has changed the
2178        compiled form incompatibly. Anybody with saved compiled patterns that use
2179        \p or \P will have to recompile them.
2181    22. Added "Any" and "L&" to the supported property types.
2183    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2184        but give a compile time error if the value is greater than 0xff.
2186    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2187        accidentally not being installed or uninstalled.
2189    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2190        made were to insert the current release number. This seemed silly, because
2191        it made things harder for people building PCRE on systems that don't run
2192        "configure". I have turned pcre.h into a distributed file, no longer built
2193        by "configure", with the version identification directly included. There is
2194        no longer a pcre.h.in file.
2196        However, this change necessitated a change to the pcre-config script as
2197        well. It is built from pcre-config.in, and one of the substitutions was the
2198        release number. I have updated configure.ac so that ./configure now finds
2199        the release number by grepping pcre.h.
2201    26. Added the ability to run the tests under valgrind.
2204    Version 6.4 05-Sep-05
2205    ---------------------
2207     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2208        "--" to be printed when multiple files were scanned, even when none of the
2209        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2210        consider it to be a bug, and have restored the previous behaviour.
2212     2. A couple of code tidies to get rid of compiler warnings.
2214     3. The pcretest program used to cheat by referring to symbols in the library
2215        whose names begin with _pcre_. These are internal symbols that are not
2216        really supposed to be visible externally, and in some environments it is
2217        possible to suppress them. The cheating is now confined to including
2218        certain files from the library's source, which is a bit cleaner.
2220     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2221        file's purpose clearer.
2223     5. Reorganized pcre_ucp_findchar().
2226    Version 6.3 15-Aug-05
2227    ---------------------
2229     1. The file libpcre.pc.in did not have general read permission in the tarball.
2231     2. There were some problems when building without C++ support:
2233        (a) If C++ support was not built, "make install" and "make test" still
2234            tried to test it.
2236        (b) There were problems when the value of CXX was explicitly set. Some
2237            changes have been made to try to fix these, and ...
2239        (c) --disable-cpp can now be used to explicitly disable C++ support.
2241        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2242            backslash in a target when C++ was disabled. This confuses some
2243            versions of "make", apparently. Using an intermediate variable solves
2244            this. (Same for CPP_LOBJ.)
2246     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2247        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2248        necessary on certain architectures.
2250     4. Added a setting of -export-symbols-regex to the link command to remove
2251        those symbols that are exported in the C sense, but actually are local
2252        within the library, and not documented. Their names all begin with
2253        "_pcre_". This is not a perfect job, because (a) we have to except some
2254        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2255        available (and never for static libraries). I have made a note to try to
2256        find a way round (a) in the future.
2259  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
2260  ---------------------  ---------------------

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