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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.2 01-May-07  Version 8.10 03-Jun-2010
5    ------------------------
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
10    2.  (*ACCEPT) was not working when inside an atomic group.
12    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
23    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
29    7.  Minor change to pcretest.c to avoid a compiler warning.
31    8.  Added four artifical Unicode properties to help with an option to make
32        \s etc use properties (see next item). The new properties are: Xan
33        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
35    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
36        use Unicode properties. (*UCP) at the start of a pattern can be used to set
37        this option. Modified pcretest to add /W to test this facility. Added
38        REG_UCP to make it available via the POSIX interface.
40    10. Added --line-buffered to pcregrep.
42    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
43        studied, and the match started with a letter with a code point greater than
44        127 whose first byte was different to the first byte of the other case of
45        the letter, the other case of this starting letter was not recognized
46        (#976).
48    12. If a pattern that was studied started with a repeated Unicode property
49        test, for example, \p{Nd}+, there was the theoretical possibility of
50        setting up an incorrect bitmap of starting bytes, but fortunately it could
51        not have actually happened in practice until change 8 above was made (it
52        added property types that matched character-matching opcodes).
54    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
55        possible starting bytes for non-anchored patterns.
57    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
58        \R, and also a number of cases that involve Unicode properties, both
59        explicit and implicit when PCRE_UCP is set.
61    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
62        input, it could crash or give wrong results if characters with values
63        greater than 0xc0 were present in the subject string. (Detail: it assumed
64        UTF-8 input when processing these items.)
66    16. Added a lot of (int) casts to avoid compiler warnings in systems where
67        size_t is 64-bit (#991).
69    17. Added a check for running out of memory when PCRE is compiled with
70        --disable-stack-for-recursion (#990).
72    18. If the last data line in a file for pcretest does not have a newline on
73        the end, a newline was missing in the output.
75    19. The default pcre_chartables.c file recognizes only ASCII characters (values
76        less than 128) in its various bitmaps. However, there is a facility for
77        generating tables according to the current locale when PCRE is compiled. It
78        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
79        characters, are recognized by isspace() and therefore were getting set in
80        these tables, and indeed these tables seem to approximate to ISO 8859. This
81        caused a problem in UTF-8 mode when pcre_study() was used to create a list
82        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
83        which of course cannot start UTF-8 characters. I have changed the code so
84        that only real ASCII characters (less than 128) and the correct starting
85        bytes for UTF-8 encodings are set for characters greater than 127 when in
86        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
87        altogether.)
89    20. Added the /T option to pcretest so as to be able to run tests with non-
90        standard character tables, thus making it possible to include the tests
91        used for 19 above in the standard set of tests.
94    Version 8.02 19-Mar-2010
95    ------------------------
97    1.  The Unicode data tables have been updated to Unicode 5.2.0.
99    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
100        configured.
102    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
103        original author of that file, following a query about its status.
105    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
106        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
108    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
109        quantifier applied to a forward-referencing subroutine call, could compile
110        incorrect code or give the error "internal error: previously-checked
111        referenced subpattern not found".
113    6.  Both MS Visual Studio and Symbian OS have problems with initializing
114        variables to point to external functions. For these systems, therefore,
115        pcre_malloc etc. are now initialized to local functions that call the
116        relevant global functions.
118    7.  There were two entries missing in the vectors called coptable and poptable
119        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
120        I've fixed the data, and added a kludgy way of testing at compile time that
121        the lengths are correct (equal to the number of opcodes).
123    8.  Following on from 7, I added a similar kludge to check the length of the
124        eint vector in pcreposix.c.
126    9.  Error texts for pcre_compile() are held as one long string to avoid too
127        much relocation at load time. To find a text, the string is searched,
128        counting zeros. There was no check for running off the end of the string,
129        which could happen if a new error number was added without updating the
130        string.
132    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
134    11. \K was not working if it appeared in an atomic group or in a group that
135        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
136        \K is "not well defined" if used in an assertion. PCRE now accepts it if
137        the assertion is positive, but not if it is negative.
139    12. Change 11 fortuitously reduced the size of the stack frame used in the
140        "match()" function of pcre_exec.c by one pointer. Forthcoming
141        implementation of support for (*MARK) will need an extra pointer on the
142        stack; I have reserved it now, so that the stack frame size does not
143        decrease.
145    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
146        item in branch that calls a recursion is a subroutine call - as in the
147        second branch in the above example - was incorrectly given the compile-
148        time error "recursive call could loop indefinitely" because pcre_compile()
149        was not correctly checking the subroutine for matching a non-empty string.
151    14. The checks for overrunning compiling workspace could trigger after an
152        overrun had occurred. This is a "should never occur" error, but it can be
153        triggered by pathological patterns such as hundreds of nested parentheses.
154        The checks now trigger 100 bytes before the end of the workspace.
156    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
159    Version 8.01 19-Jan-2010
160    ------------------------
162    1.  If a pattern contained a conditional subpattern with only one branch (in
163        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
164        computed the wrong minimum data length (which is of course zero for such
165        subpatterns). This could cause incorrect "no match" results.
167    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
168        the pattern is reset in the first branch, pcre_compile() failed with
169        "internal error: code overflow at offset...". This happened only when
170        the reset was to the original external option setting. (An optimization
171        abstracts leading options settings into an external setting, which was the
172        cause of this.)
174    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
175        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
176        assertion pattern did not match (meaning that the assertion was true), it
177        was incorrectly treated as false if the SKIP had been reached during the
178        matching. This also applied to assertions used as conditions.
180    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
181        assertion subpattern, including such a pattern used as a condition,
182        unpredictable results occurred, instead of the error return
185    5.  The C++ GlobalReplace function was not working like Perl for the special
186        situation when an empty string is matched. It now does the fancy magic
187        stuff that is necessary.
189    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
190        removed. (These were left over from very, very early versions of PCRE.)
192    7.  Some cosmetic changes to the code to make life easier when compiling it
193        as part of something else:
195        (a) Change DEBUG to PCRE_DEBUG.
197        (b) In pcre_compile(), rename the member of the "branch_chain" structure
198            called "current" as "current_branch", to prevent a collision with the
199            Linux macro when compiled as a kernel module.
201        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
202            prevent a collision with the Linux macro when compiled as a kernel
203            module.
205    8.  In pcre_compile() there are some checks for integer overflows that used to
206        cast potentially large values to (double). This has been changed to that
207        when building, a check for int64_t is made, and if it is found, it is used
208        instead, thus avoiding the use of floating point arithmetic. (There is no
209        other use of FP in PCRE.) If int64_t is not found, the fallback is to
210        double.
212    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
213        2005 (difference between two addresses compared to an unsigned value).
215    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
216        custom one, because of the following reported problem in Windows:
218          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
219              under Win32.
220          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
221              therefore missing the function definition.
222          - The compiler thus generates a "C" signature for the test function.
223          - The linker fails to find the "C" function.
224          - PCRE fails to configure if asked to do so against libbz2.
226    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
227        messages were output:
229          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
230          rerunning libtoolize, to keep the correct libtool macros in-tree.
231          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
233        I have done both of these things.
235    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
236        most of the time, it *can* run out if it is given a pattern that contains a
237        runaway infinite recursion. I updated the discussion in the pcrestack man
238        page.
240    13. Now that we have gone to the x.xx style of version numbers, the minor
241        version may start with zero. Using 08 or 09 is a bad idea because users
242        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
243        interpreted as invalid octal numbers. I've updated the previous comment in
244        configure.ac, and also added a check that gives an error if 08 or 09 are
245        used.
247    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
248        causing partial matching to fail when the end of the subject matched \W
249        in a UTF-8 pattern where \W was quantified with a minimum of 3.
251    15. There were some discrepancies between the declarations in pcre_internal.h
252        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
253        their definitions. The declarations used "const uschar *" and the
254        definitions used USPTR. Even though USPTR is normally defined as "const
255        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
256        reported that: "This difference in casting confuses some C++ compilers, for
257        example, SunCC recognizes above declarations as different functions and
258        generates broken code for hbpcre." I have changed the declarations to use
259        USPTR.
261    16. GNU libtool is named differently on some systems. The autogen.sh script now
262        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
263        (FreeBSD).
265    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
266        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
267        comment: "Figure out how to create a longlong from a string: strtoll and
268        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
269        instance, but it only takes 2 args instead of 3!"
271    18. A subtle bug concerned with back references has been fixed by a change of
272        specification, with a corresponding code fix. A pattern such as
273        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
274        refers, was giving matches when it shouldn't. For example, xa=xaaa would
275        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
276        same bug. Such groups have to be quantified to be useful, or contained
277        inside another quantified group. (If there's no repetition, the reference
278        can never match.) The problem arises because, having left the group and
279        moved on to the rest of the pattern, a later failure that backtracks into
280        the group uses the captured value from the final iteration of the group
281        rather than the correct earlier one. I have fixed this in PCRE by forcing
282        any group that contains a reference to itself to be an atomic group; that
283        is, there cannot be any backtracking into it once it has completed. This is
284        similar to recursive and subroutine calls.
287    Version 8.00 19-Oct-09
288    ----------------------
290    1.  The table for translating pcre_compile() error codes into POSIX error codes
291        was out-of-date, and there was no check on the pcre_compile() error code
292        being within the table. This could lead to an OK return being given in
293        error.
295    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
296        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
297        in a Windows environment.
299    3.  The pcregrep --count option prints the count for each file even when it is
300        zero, as does GNU grep. However, pcregrep was also printing all files when
301        --files-with-matches was added. Now, when both options are given, it prints
302        counts only for those files that have at least one match. (GNU grep just
303        prints the file name in this circumstance, but including the count seems
304        more useful - otherwise, why use --count?) Also ensured that the
305        combination -clh just lists non-zero counts, with no names.
307    4.  The long form of the pcregrep -F option was incorrectly implemented as
308        --fixed_strings instead of --fixed-strings. This is an incompatible change,
309        but it seems right to fix it, and I didn't think it was worth preserving
310        the old behaviour.
312    5.  The command line items --regex=pattern and --regexp=pattern were not
313        recognized by pcregrep, which required --regex pattern or --regexp pattern
314        (with a space rather than an '='). The man page documented the '=' forms,
315        which are compatible with GNU grep; these now work.
317    6.  No libpcreposix.pc file was created for pkg-config; there was just
318        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
320    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
321        when UCP support is not needed, by modifying the Python script that
322        generates it from Unicode data files. This should not matter if the module
323        is correctly used as a library, but I received one complaint about 50K of
324        unwanted data. My guess is that the person linked everything into his
325        program rather than using a library. Anyway, it does no harm.
327    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
328        was a minimum greater than 1 for a wide character in a possessive
329        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
330        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
331        character. Chaos in the form of incorrect output or a compiling loop could
332        result.
334    9.  The restrictions on what a pattern can contain when partial matching is
335        requested for pcre_exec() have been removed. All patterns can now be
336        partially matched by this function. In addition, if there are at least two
337        slots in the offset vector, the offset of the earliest inspected character
338        for the match and the offset of the end of the subject are set in them when
339        PCRE_ERROR_PARTIAL is returned.
341    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
342        synonymous with PCRE_PARTIAL, for backwards compatibility, and
343        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
344        and may be more useful for multi-segment matching.
346    11. Partial matching with pcre_exec() is now more intuitive. A partial match
347        used to be given if ever the end of the subject was reached; now it is
348        given only if matching could not proceed because another character was
349        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
350        string "Z", which now yields "no match" instead of "partial match". In the
351        case of pcre_dfa_exec(), "no match" is given if every matching path for the
352        final character ended with (*FAIL).
354    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
355        if the pattern had a "must contain" character that was already found in the
356        earlier partial match, unless partial matching was again requested. For
357        example, with the pattern /dog.(body)?/, the "must contain" character is
358        "g". If the first part-match was for the string "dog", restarting with
359        "sbody" failed. This bug has been fixed.
361    13. The string returned by pcre_dfa_exec() after a partial match has been
362        changed so that it starts at the first inspected character rather than the
363        first character of the match. This makes a difference only if the pattern
364        starts with a lookbehind assertion or \b or \B (\K is not supported by
365        pcre_dfa_exec()). It's an incompatible change, but it makes the two
366        matching functions compatible, and I think it's the right thing to do.
368    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
369        so that the demonstration program is easily available in environments where
370        PCRE has not been installed from source.
372    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
373        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
374        library.
376    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
377        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
378        is not the first non-POSIX option to be added. Clearly some people find
379        these options useful.
381    17. If a caller to the POSIX matching function regexec() passes a non-zero
382        value for nmatch with a NULL value for pmatch, the value of
383        nmatch is forced to zero.
385    18. RunGrepTest did not have a test for the availability of the -u option of
386        the diff command, as RunTest does. It now checks in the same way as
387        RunTest, and also checks for the -b option.
389    19. If an odd number of negated classes containing just a single character
390        interposed, within parentheses, between a forward reference to a named
391        subpattern and the definition of the subpattern, compilation crashed with
392        an internal error, complaining that it could not find the referenced
393        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
394        [The bug was that it was starting one character too far in when skipping
395        over the character class, thus treating the ] as data rather than
396        terminating the class. This meant it could skip too much.]
398    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
399        /g option in pcretest when the pattern contains \K, which makes it possible
400        to have an empty string match not at the start, even when the pattern is
401        anchored. Updated pcretest and pcredemo to use this option.
403    21. If the maximum number of capturing subpatterns in a recursion was greater
404        than the maximum at the outer level, the higher number was returned, but
405        with unset values at the outer level. The correct (outer level) value is
406        now given.
408    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
409        PCRE did not set those parentheses (unlike Perl). I have now found a way to
410        make it do so. The string so far is captured, making this feature
411        compatible with Perl.
413    23. The tests have been re-organized, adding tests 11 and 12, to make it
414        possible to check the Perl 5.10 features against Perl 5.10.
416    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
417        pattern matches a fixed length string. PCRE did not allow this; now it
418        does. Neither allows recursion.
420    25. I finally figured out how to implement a request to provide the minimum
421        length of subject string that was needed in order to match a given pattern.
422        (It was back references and recursion that I had previously got hung up
423        on.) This code has now been added to pcre_study(); it finds a lower bound
424        to the length of subject needed. It is not necessarily the greatest lower
425        bound, but using it to avoid searching strings that are too short does give
426        some useful speed-ups. The value is available to calling programs via
427        pcre_fullinfo().
429    26. While implementing 25, I discovered to my embarrassment that pcretest had
430        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
431        study optimizations had never been tested with that matching function.
432        Oops. What is worse, even when it was passed study data, there was a bug in
433        pcre_dfa_exec() that meant it never actually used it. Double oops. There
434        were also very few tests of studied patterns with pcre_dfa_exec().
436    27. If (?| is used to create subpatterns with duplicate numbers, they are now
437        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
438        on the other side of the coin, they are no longer allowed to have different
439        names, because these cannot be distinguished in PCRE, and this has caused
440        confusion. (This is a difference from Perl.)
442    28. When duplicate subpattern names are present (necessarily with different
443        numbers, as required by 27 above), and a test is made by name in a
444        conditional pattern, either for a subpattern having been matched, or for
445        recursion in such a pattern, all the associated numbered subpatterns are
446        tested, and the overall condition is true if the condition is true for any
447        one of them. This is the way Perl works, and is also more like the way
448        testing by number works.
451    Version 7.9 11-Apr-09
452    ---------------------
454    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
455        (pcretest), all targets were linked against these libraries. This included
456        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
457        libraries. This caused unwanted dependencies to be created. This problem
458        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
459        pcretest is linked with readline.
461    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
462        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
463        moved outside it again, because FALSE and TRUE are already defined in AIX,
464        but BOOL is not.
466    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
467        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
469    4.  The pcregrep documentation said spaces were inserted as well as colons (or
470        hyphens) following file names and line numbers when outputting matching
471        lines. This is not true; no spaces are inserted. I have also clarified the
472        wording for the --colour (or --color) option.
474    5.  In pcregrep, when --colour was used with -o, the list of matching strings
475        was not coloured; this is different to GNU grep, so I have changed it to be
476        the same.
478    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
479        each matching line was coloured. Now it goes on to look for further matches
480        of any of the test patterns, which is the same behaviour as GNU grep.
482    7.  A pattern that could match an empty string could cause pcregrep to loop; it
483        doesn't make sense to accept an empty string match in pcregrep, so I have
484        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
485        seems to be how GNU grep behaves.
487    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
488        start or after a newline", because the conditional assertion was not being
489        correctly handled. The rule now is that both the assertion and what follows
490        in the first alternative must satisfy the test.
492    9.  If auto-callout was enabled in a pattern with a conditional group whose
493        condition was an assertion, PCRE could crash during matching, both with
494        pcre_exec() and pcre_dfa_exec().
496    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
497        used for matching.
499    11. Unicode property support in character classes was not working for
500        characters (bytes) greater than 127 when not in UTF-8 mode.
502    12. Added the -M command line option to pcretest.
504    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
506    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
508    16. Added comments and documentation about mis-use of no_arg in the C++
509        wrapper.
511    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
512        from Martin Jerabek that uses macro names for all relevant character and
513        string constants.
515    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
516        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
517        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
518        these, but not everybody uses configure.
520    19. A conditional group that had only one branch was not being correctly
521        recognized as an item that could match an empty string. This meant that an
522        enclosing group might also not be so recognized, causing infinite looping
523        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
524        with the subject "ab", where knowledge that the repeated group can match
525        nothing is needed in order to break the loop.
527    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
528        exec(), but without supplying a callout function, matching went wrong.
530    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
531        leak if the size of the offset vector was greater than 30. When the vector
532        is smaller, the saved offsets during recursion go onto a local stack
533        vector, but for larger vectors malloc() is used. It was failing to free
534        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
535        error, in fact).
537    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
538        heapframe that is used only when UTF-8 support is enabled. This caused no
539        problem, but was untidy.
541    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
542        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
543        included within another project.
545    24. Steven Van Ingelgem's patches to add more options to the CMake support,
546        slightly modified by me:
548          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
549              not building pcregrep.
551          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
552              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
554    25. Forward references, both numeric and by name, in patterns that made use of
555        duplicate group numbers, could behave incorrectly or give incorrect errors,
556        because when scanning forward to find the reference group, PCRE was not
557        taking into account the duplicate group numbers. A pattern such as
558        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
560    26. Changed a few more instances of "const unsigned char *" to USPTR, making
561        the feature of a custom pointer more persuasive (as requested by a user).
563    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
564        pcretest.c, inside #ifndefs, because it seems they are sometimes already
565        pre-defined.
567    28. Added support for (*UTF8) at the start of a pattern.
569    29. Arrange for flags added by the "release type" setting in CMake to be shown
570        in the configuration summary.
573    Version 7.8 05-Sep-08
574    ---------------------
576    1.  Replaced UCP searching code with optimized version as implemented for Ad
577        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
578        stage table and inline lookup instead of a function, giving speed ups of 2
579        to 5 times on some simple patterns that I tested. Permission was given to
580        distribute the MultiStage2.py script that generates the tables (it's not in
581        the tarball, but is in the Subversion repository).
583    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
584        scripts.
586    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
587        a group with a zero qualifier. The result of the study could be incorrect,
588        or the function might crash, depending on the pattern.
590    4.  Caseless matching was not working for non-ASCII characters in back
591        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
592        It now works when Unicode Property Support is available.
594    5.  In pcretest, an escape such as \x{de} in the data was always generating
595        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
596        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
597        truncation.
599    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
601    7.  Added two (int) casts to pcregrep when printing the difference of two
602        pointers, in case they are 64-bit values.
604    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
605        test 2 if it fails.
607    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
608        and a #define of that name to empty if it is not externally set. This is to
609        allow users of MSVC to set it if necessary.
611    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
612        the convenience functions in the pcre_get.c source file.
614    11. An option change at the start of a pattern that had top-level alternatives
615        could cause overwriting and/or a crash. This command provoked a crash in
616        some environments:
618          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
620        This potential security problem was recorded as CVE-2008-2371.
622    12. For a pattern where the match had to start at the beginning or immediately
623        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
624        pcre_dfa_exec() could read past the end of the passed subject if there was
625        no match. To help with detecting such bugs (e.g. with valgrind), I modified
626        pcretest so that it places the subject at the end of its malloc-ed buffer.
628    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
629        exec() might read past the end of the data buffer in UTF-8 mode.
631    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
632        the data contained the byte 0x85 as part of a UTF-8 character within its
633        first line. This applied both to normal and DFA matching.
635    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
636        /^[^d]*?$/8 failed to match "abc".
638    16. Added a missing copyright notice to pcrecpp_internal.h.
640    17. Make it more clear in the documentation that values returned from
641        pcre_exec() in ovector are byte offsets, not character counts.
643    18. Tidied a few places to stop certain compilers from issuing warnings.
645    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
646        supplied by Stefan Weber. I made a further small update for 7.8 because
647        there is a change of source arrangements: the pcre_searchfuncs.c module is
648        replaced by pcre_ucd.c.
651    Version 7.7 07-May-08
652    ---------------------
654    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
655        a string to a long long, pretend we don't even have a long long." This is
656        done by checking for the strtoq, strtoll, and _strtoi64 functions.
658    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
659        pre-7.6 versions, which defined a global no_arg variable instead of putting
660        it in the RE class. (See also #8 below.)
662    3.  Remove a line of dead code, identified by coverity and reported by Nuno
663        Lopes.
665    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
667        (1) The include/exclude patterns were being applied to the whole pathnames
668            of files, instead of just to the final components.
670        (2) If there was more than one level of directory, the subdirectories were
671            skipped unless they satisfied the include/exclude conditions. This is
672            inconsistent with GNU grep (and could even be seen as contrary to the
673            pcregrep specification - which I improved to make it absolutely clear).
674            The action now is always to scan all levels of directory, and just
675            apply the include/exclude patterns to regular files.
677    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
678        --exclude_dir in the tests to avoid scanning .svn directories.
680    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
681        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
682        doesn't support NULs in patterns.
684    7.  Added some missing "const"s to declarations of static tables in
685        pcre_compile.c and pcre_dfa_exec.c.
687    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
688        caused by fix #2  above. (Subsequently also a second patch to fix the
689        first patch. And a third patch - this was a messy problem.)
691    9.  Applied Craig's patch to remove the use of push_back().
693    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
694        matching function regexec().
696    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
697        which, however, unlike Perl's \g{...}, are subroutine calls, not back
698        references. PCRE supports relative numbers with this syntax (I don't think
699        Oniguruma does).
701    12. Previously, a group with a zero repeat such as (...){0} was completely
702        omitted from the compiled regex. However, this means that if the group
703        was called as a subroutine from elsewhere in the pattern, things went wrong
704        (an internal error was given). Such groups are now left in the compiled
705        pattern, with a new opcode that causes them to be skipped at execution
706        time.
708    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
709        to the way PCRE behaves:
711        (a) A lone ] character is dis-allowed (Perl treats it as data).
713        (b) A back reference to an unmatched subpattern matches an empty string
714            (Perl fails the current match path).
716        (c) A data ] in a character class must be notated as \] because if the
717            first data character in a class is ], it defines an empty class. (In
718            Perl it is not possible to have an empty class.) The empty class []
719            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
720            The negative empty class [^] matches any one character, independently
721            of the DOTALL setting.
723    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
724        non-existent subpattern following a character class starting with ']' and
725        containing () gave an internal compiling error instead of "reference to
726        non-existent subpattern". Fortunately, when the pattern did exist, the
727        compiled code was correct. (When scanning forwards to check for the
728        existencd of the subpattern, it was treating the data ']' as terminating
729        the class, so got the count wrong. When actually compiling, the reference
730        was subsequently set up correctly.)
732    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
733        it was being rejected as not supported by pcre_dfa_exec(), even though
734        other assertions are supported. I have made pcre_dfa_exec() support
735        (*FAIL).
737    16. The implementation of 13c above involved the invention of a new opcode,
738        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
739        cannot be changed at match time, I realized I could make a small
740        improvement to matching performance by compiling OP_ALLANY instead of
741        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
742        on the OP_ANY path.
744    17. Compiling pcretest on Windows with readline support failed without the
745        following two fixes: (1) Make the unistd.h include conditional on
746        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
748    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
749        ncurses library to be included for pcretest when ReadLine support is
750        requested, but also to allow for it to be overridden. This patch came from
751        Daniel Bergström.
753    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
754        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
755        any errors with the current Unicode tables. Thanks to Peter Kankowski for
756        spotting this.
759    Version 7.6 28-Jan-08
760    ---------------------
762    1.  A character class containing a very large number of characters with
763        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
764        overflow.
766    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
767        HAVE_LONG_LONG is not defined.
769    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
770        bring them up to date and include new features. This patch includes:
772        - Fixed PH's badly added libz and libbz2 support.
773        - Fixed a problem with static linking.
774        - Added pcredemo. [But later removed - see 7 below.]
775        - Fixed dftables problem and added an option.
776        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
777            HAVE_LONG_LONG.
778        - Added readline support for pcretest.
779        - Added an listing of the option settings after cmake has run.
781    4.  A user submitted a patch to Makefile that makes it easy to create
782        "pcre.dll" under mingw when using Configure/Make. I added stuff to
783        Makefile.am that cause it to include this special target, without
784        affecting anything else. Note that the same mingw target plus all
785        the other distribution libraries and programs are now supported
786        when configuring with CMake (see 6 below) instead of with
787        Configure/Make.
789    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
790        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
791        exported in the Windows port". It has not yet been confirmed that the patch
792        solves the problem, but it does no harm.
794    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
795        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
796        with CMake, and also correct the comment about stack recursion.
798    7.  Remove the automatic building of pcredemo from the ./configure system and
799        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
800        of a program that users should build themselves after PCRE is installed, so
801        building it automatically is not really right. What is more, it gave
802        trouble in some build environments.
804    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
807    Version 7.5 10-Jan-08
808    ---------------------
810    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
811        values in parens when parsing an RE using the C++ wrapper."
813    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
814        Characters greater than 255 were excluded from the class instead of being
815        included.
817    3.  The same bug as (2) above applied to negated POSIX classes such as
818        [:^space:].
820    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
821        defined or documented. It seems to have been a typo for PCRE_STATIC, so
822        I have changed it.
824    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
825        first named subpattern) and a construct such as (?&a) would reference the
826        first named subpattern whose name started with "a" (in other words, the
827        length check was missing). Both these problems are fixed. "Subpattern name
828        expected" is now given for (?&) (a zero-length name), and this patch also
829        makes it give the same error for \k'' (previously it complained that that
830        was a reference to a non-existent subpattern).
832    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
833        this is right because (?- can be followed by option settings as well as by
834        digits. I have, however, made the messages clearer.
836    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
837        than the number used in the conditional) now cause a compile-time error.
838        This is actually not compatible with Perl, which accepts such patterns, but
839        treats the conditional as always being FALSE (as PCRE used to), but it
840        seems to me that giving a diagnostic is better.
842    8.  Change "alphameric" to the more common word "alphanumeric" in comments
843        and messages.
845    9.  Fix two occurrences of "backslash" in comments that should have been
846        "backspace".
848    10. Remove two redundant lines of code that can never be obeyed (their function
849        was moved elsewhere).
851    11. The program that makes PCRE's Unicode character property table had a bug
852        which caused it to generate incorrect table entries for sequences of
853        characters that have the same character type, but are in different scripts.
854        It amalgamated them into a single range, with the script of the first of
855        them. In other words, some characters were in the wrong script. There were
856        thirteen such cases, affecting characters in the following ranges:
858          U+002b0 - U+002c1
859          U+0060c - U+0060d
860          U+0061e - U+00612
861          U+0064b - U+0065e
862          U+0074d - U+0076d
863          U+01800 - U+01805
864          U+01d00 - U+01d77
865          U+01d9b - U+01dbf
866          U+0200b - U+0200f
867          U+030fc - U+030fe
868          U+03260 - U+0327f
869          U+0fb46 - U+0fbb1
870          U+10450 - U+1049d
872    12. The -o option (show only the matching part of a line) for pcregrep was not
873        compatible with GNU grep in that, if there was more than one match in a
874        line, it showed only the first of them. It now behaves in the same way as
875        GNU grep.
877    13. If the -o and -v options were combined for pcregrep, it printed a blank
878        line for every non-matching line. GNU grep prints nothing, and pcregrep now
879        does the same. The return code can be used to tell if there were any
880        non-matching lines.
882    14. Added --file-offsets and --line-offsets to pcregrep.
884    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
885        infinitely looping recursion. The bug was that positive lookaheads were not
886        being skipped when checking for a possible empty match (negative lookaheads
887        and both kinds of lookbehind were skipped).
889    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
890        inclusion of <windows.h> to before rather than after the definition of
891        INVALID_FILE_ATTRIBUTES (patch from David Byron).
893    17. Specifying a possessive quantifier with a specific limit for a Unicode
894        character property caused pcre_compile() to compile bad code, which led at
895        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
896        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
897        caused the error; without that there was no problem.
899    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
901    19. Added --enable-pcretest-libreadline.
903    20. In pcrecpp.cc, the variable 'count' was incremented twice in
904        RE::GlobalReplace(). As a result, the number of replacements returned was
905        double what it should be. I removed one of the increments, but Craig sent a
906        later patch that removed the other one (the right fix) and added unit tests
907        that check the return values (which was not done before).
909    21. Several CMake things:
911        (1) Arranged that, when cmake is used on Unix, the libraries end up with
912            the names libpcre and libpcreposix, not just pcre and pcreposix.
914        (2) The above change means that pcretest and pcregrep are now correctly
915            linked with the newly-built libraries, not previously installed ones.
919    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
920        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
921        UTF-8 newline character). The key issue is that the pattern starts .*;
922        this means that the match must be either at the beginning, or after a
923        newline. The bug was in the code for advancing after a failed match and
924        checking that the new position followed a newline. It was not taking
925        account of UTF-8 characters correctly.
927    23. PCRE was behaving differently from Perl in the way it recognized POSIX
928        character classes. PCRE was not treating the sequence [:...:] as a
929        character class unless the ... were all letters. Perl, however, seems to
930        allow any characters between [: and :], though of course it rejects as
931        unknown any "names" that contain non-letters, because all the known class
932        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
933        for example, whereas PCRE did not - it did not recognize a POSIX character
934        class. This seemed a bit dangerous, so the code has been changed to be
935        closer to Perl. The behaviour is not identical to Perl, because PCRE will
936        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
937        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
938        Perl does, and where it didn't before.
940    24. Rewrite so as to remove the single use of %n from pcregrep because in some
941        Windows environments %n is disabled by default.
944    Version 7.4 21-Sep-07
945    ---------------------
947    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
948        means that a class such as [\s] counted as "explicit reference to CR or
949        LF". That isn't really right - the whole point of the change was to try to
950        help when there was an actual mention of one of the two characters. So now
951        the change happens only if \r or \n (or a literal CR or LF) character is
952        encountered.
954    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
955        of both had grown to the point where there were only 3 bits left.
956        Fortunately, there was spare space in the data structure, and so I have
957        moved the internal flags into a new 16-bit field to free up more option
958        bits.
960    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
961        but did not set the internal JCHANGED flag - either of these is enough to
962        control the way the "get" function works - but the PCRE_INFO_JCHANGED
963        facility is supposed to tell if (?J) was ever used, so now (?J) at the
964        start sets both bits.
966    4.  Added options (at build time, compile time, exec time) to change \R from
967        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
969    5.  doc/pcresyntax.html was missing from the distribution.
971    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
972        compatibility, even though it is no longer used.
974    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
975        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
976        windows.h file is present (where different names are used). [This was
977        reversed later after testing - see 16 below.]
979    8.  Changed all #include <config.h> to #include "config.h". There were also
980        some further <pcre.h> cases that I changed to "pcre.h".
982    9.  When pcregrep was used with the --colour option, it missed the line ending
983        sequence off the lines that it output.
985    10. It was pointed out to me that arrays of string pointers cause lots of
986        relocations when a shared library is dynamically loaded. A technique of
987        using a single long string with a table of offsets can drastically reduce
988        these. I have refactored PCRE in four places to do this. The result is
989        dramatic:
991          Originally:                          290
992          After changing UCP table:            187
993          After changing error message table:   43
994          After changing table of "verbs"       36
995          After changing table of Posix names   22
997        Thanks to the folks working on Gregex for glib for this insight.
999    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1000        unicode-properties was also set.
1002    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1004    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1005        checked only for CRLF.
1007    14. Added casts to pcretest.c to avoid compiler warnings.
1009    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1011    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1012        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1013        entirely. This removes changes made in 7 above.
1015    17. The CMake files have been updated, and there is now more information about
1016        building with CMake in the NON-UNIX-USE document.
1019    Version 7.3 28-Aug-07
1020    ---------------------
1022     1. In the rejigging of the build system that eventually resulted in 7.1, the
1023        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1024        brackets there is not right, since it causes compilers to look for an
1025        installed pcre.h, not the version that is in the source that is being
1026        compiled (which of course may be different). I have changed it back to:
1028          #include "pcre.h"
1030        I have a vague recollection that the change was concerned with compiling in
1031        different directories, but in the new build system, that is taken care of
1032        by the VPATH setting the Makefile.
1034     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1035        when the subject happened to end in the byte 0x85 (e.g. if the last
1036        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1037        characters but of course it shouldn't be taken as a newline when it is part
1038        of another character. The bug was that, for an unlimited repeat of . in
1039        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1040        characters when looking for a newline.
1042     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1044     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1045        in debug output.
1047     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1048        long printing in the pcrecpp unittest when running under MinGW.
1050     6. ESC_K was left out of the EBCDIC table.
1052     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1053        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1054        limit also applies to "virtual nesting" when a pattern is recursive, and in
1055        this case 1000 isn't so big. I have been able to remove this limit at the
1056        expense of backing off one optimization in certain circumstances. Normally,
1057        when pcre_exec() would call its internal match() function recursively and
1058        immediately return the result unconditionally, it uses a "tail recursion"
1059        feature to save stack. However, when a subpattern that can match an empty
1060        string has an unlimited repetition quantifier, it no longer makes this
1061        optimization. That gives it a stack frame in which to save the data for
1062        checking that an empty string has been matched. Previously this was taken
1063        from the 1000-entry workspace that had been reserved. So now there is no
1064        explicit limit, but more stack is used.
1066     8. Applied Daniel's patches to solve problems with the import/export magic
1067        syntax that is required for Windows, and which was going wrong for the
1068        pcreposix and pcrecpp parts of the library. These were overlooked when this
1069        problem was solved for the main library.
1071     9. There were some crude static tests to avoid integer overflow when computing
1072        the size of patterns that contain repeated groups with explicit upper
1073        limits. As the maximum quantifier is 65535, the maximum group length was
1074        set at 30,000 so that the product of these two numbers did not overflow a
1075        32-bit integer. However, it turns out that people want to use groups that
1076        are longer than 30,000 bytes (though not repeat them that many times).
1077        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1078        made it possible to implement the integer overflow checks in a much more
1079        dynamic way, which I have now done. The artificial limitation on group
1080        length has been removed - we now have only the limit on the total length of
1081        the compiled pattern, which depends on the LINK_SIZE setting.
1083    10. Fixed a bug in the documentation for get/copy named substring when
1084        duplicate names are permitted. If none of the named substrings are set, the
1085        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1086        empty string.
1088    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1089        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1090        because the ] is interpreted as the first data character and the
1091        terminating ] is not found. PCRE has been made compatible with Perl in this
1092        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1093        cause memory overwriting.
1095    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1096        string has been matched (to stop an infinite loop). It was not recognizing
1097        a conditional subpattern that could match an empty string if that
1098        subpattern was within another subpattern. For example, it looped when
1099        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1100        condition was not nested. This bug has been fixed.
1102    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1103        past the start of the subject in the presence of bytes with the top bit
1104        set, for example "\x8aBCD".
1106    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1107        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1109    14. Optimized (?!) to (*FAIL).
1111    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1112        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1113        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1114        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1115        does: it's just the validity check that is more restrictive.
1117    16. Inserted checks for integer overflows during escape sequence (backslash)
1118        processing, and also fixed erroneous offset values for syntax errors during
1119        backslash processing.
1121    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1122        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1124    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1125        caused an overrun.
1127    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1128        something other than just ASCII characters) inside a group that had an
1129        unlimited repeat caused a loop at compile time (while checking to see
1130        whether the group could match an empty string).
1132    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1133        [\P{Any}] did so. (Error in the code for printing property names.)
1135    21. An orphan \E inside a character class could cause a crash.
1137    22. A repeated capturing bracket such as (A)? could cause a wild memory
1138        reference during compilation.
1140    23. There are several functions in pcre_compile() that scan along a compiled
1141        expression for various reasons (e.g. to see if it's fixed length for look
1142        behind). There were bugs in these functions when a repeated \p or \P was
1143        present in the pattern. These operators have additional parameters compared
1144        with \d, etc, and these were not being taken into account when moving along
1145        the compiled data. Specifically:
1147        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1148            length.
1150        (b) An item such as \pL+ within a repeated group could cause crashes or
1151            loops.
1153        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1154            "reference to non-existent subpattern" error.
1156        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1158    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1159        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1161    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1163    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1164        character were causing crashes (broken optimization).
1166    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1167        \p or \P) caused a compile-time loop.
1169    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1170        break. For example, the unstudied pattern [\r\n]A does not match the string
1171        "\r\nA" because change 7.0/46 below moves the current point on by two
1172        characters after failing to match at the start. However, the pattern \nA
1173        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1174        the same is true. There doesn't seem any very clean way out of this, but
1175        what I have chosen to do makes the common cases work: PCRE now takes note
1176        of whether there can be an explicit match for \r or \n anywhere in the
1177        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1178        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1179        pattern has explicit CR or LF references.
1181    29. Added (*CR) etc for changing newline setting at start of pattern.
1184    Version 7.2 19-Jun-07
1185  ---------------------  ---------------------
1187   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
# Line 21  Version 7.2 01-May-07 Line 1201  Version 7.2 01-May-07
1201      stack recursion. This gives a massive performance boost under BSD, but just      stack recursion. This gives a massive performance boost under BSD, but just
1202      a small improvement under Linux. However, it saves one field in the frame      a small improvement under Linux. However, it saves one field in the frame
1203      in all cases.      in all cases.
1205   6. Added more features from the forthcoming Perl 5.10:   6. Added more features from the forthcoming Perl 5.10:
1207      (a) (?-n) (where n is a string of digits) is a relative subroutine or      (a) (?-n) (where n is a string of digits) is a relative subroutine or
1208          recursion call. It refers to the nth most recently opened parentheses.          recursion call. It refers to the nth most recently opened parentheses.
1210      (b) (?+n) is also a relative subroutine call; it refers to the nth next      (b) (?+n) is also a relative subroutine call; it refers to the nth next
1211          to be opened parentheses.          to be opened parentheses.
1213      (c) Conditions that refer to capturing parentheses can be specified      (c) Conditions that refer to capturing parentheses can be specified
1214          relatively, for example, (?(-2)... or (?(+3)...          relatively, for example, (?(-2)... or (?(+3)...
1216      (d) \K resets the start of the current match so that everything before      (d) \K resets the start of the current match so that everything before
1217          is not part of it.          is not part of it.
1219        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1221        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1222            reference syntax.
1224        (g) (?| introduces a group in which the numbering of parentheses in each
1225            alternative starts with the same number.
1227        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1229     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1232     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1233        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1234        for detecting groups that can match an empty string.
1236     9. A pattern with a very large number of alternatives (more than several
1237        hundred) was running out of internal workspace during the pre-compile
1238        phase, where pcre_compile() figures out how much memory will be needed. A
1239        bit of new cunning has reduced the workspace needed for groups with
1240        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1241        workspace instead of running out of the 4096 that are available.
1243    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1245    11. Applied patch from Google to remove an optimization that didn't quite work.
1246        The report of the bug said:
1248          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1249          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1250          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1252    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1253        it matched the wrong number of bytes.
1256  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07

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