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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    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.
47    12. pcreposix.c included pcre.h before including pcre_internal.h. This caused a
48        conflict in the definition of PCRE_EXP_DECL. I have removed the include of
49        pcre.h as pcre_internal.h includes pcre.h itself. (This may be a bit of
50        historical tidying that never got done.)
52    13. If a pattern that was studied started with a repeated Unicode property
53        test, for example, \p{Nd}+, there was the theoretical possibility of
54        setting up an incorrect bitmap of starting bytes, but fortunately it could
55        not have actually happened in practice until change 8 above was made (it
56        added property types that matched character-matching opcodes).
58    14. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
59        possible starting bytes for non-anchored patterns.
61    15. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
62        \R, and also a number of cases that involve Unicode properties, both
63        explicit and implicit when PCRE_UCP is set.
65    16. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
66        input, it could crash or give wrong results if characters with values
67        greater than 0xc0 were present in the subject string. (Detail: it assumed
68        UTF-8 input when processing these items.)
70    17. Added a lot of (int) casts to avoid compiler warnings in systems where
71        size_t is 64-bit.
73    18. Added a check for running out of memory when PCRE is compiled with
74        --disable-stack-for-recursion.
77    Version 8.02 19-Mar-2010
78    ------------------------
80    1.  The Unicode data tables have been updated to Unicode 5.2.0.
82    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
83        configured.
85    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
86        original author of that file, following a query about its status.
88    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
89        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
91    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
92        quantifier applied to a forward-referencing subroutine call, could compile
93        incorrect code or give the error "internal error: previously-checked
94        referenced subpattern not found".
96    6.  Both MS Visual Studio and Symbian OS have problems with initializing
97        variables to point to external functions. For these systems, therefore,
98        pcre_malloc etc. are now initialized to local functions that call the
99        relevant global functions.
101    7.  There were two entries missing in the vectors called coptable and poptable
102        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
103        I've fixed the data, and added a kludgy way of testing at compile time that
104        the lengths are correct (equal to the number of opcodes).
106    8.  Following on from 7, I added a similar kludge to check the length of the
107        eint vector in pcreposix.c.
109    9.  Error texts for pcre_compile() are held as one long string to avoid too
110        much relocation at load time. To find a text, the string is searched,
111        counting zeros. There was no check for running off the end of the string,
112        which could happen if a new error number was added without updating the
113        string.
115    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
117    11. \K was not working if it appeared in an atomic group or in a group that
118        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
119        \K is "not well defined" if used in an assertion. PCRE now accepts it if
120        the assertion is positive, but not if it is negative.
122    12. Change 11 fortuitously reduced the size of the stack frame used in the
123        "match()" function of pcre_exec.c by one pointer. Forthcoming
124        implementation of support for (*MARK) will need an extra pointer on the
125        stack; I have reserved it now, so that the stack frame size does not
126        decrease.
128    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
129        item in branch that calls a recursion is a subroutine call - as in the
130        second branch in the above example - was incorrectly given the compile-
131        time error "recursive call could loop indefinitely" because pcre_compile()
132        was not correctly checking the subroutine for matching a non-empty string.
134    14. The checks for overrunning compiling workspace could trigger after an
135        overrun had occurred. This is a "should never occur" error, but it can be
136        triggered by pathological patterns such as hundreds of nested parentheses.
137        The checks now trigger 100 bytes before the end of the workspace.
139    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
142    Version 8.01 19-Jan-2010
143    ------------------------
145    1.  If a pattern contained a conditional subpattern with only one branch (in
146        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
147        computed the wrong minimum data length (which is of course zero for such
148        subpatterns). This could cause incorrect "no match" results.
150    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
151        the pattern is reset in the first branch, pcre_compile() failed with
152        "internal error: code overflow at offset...". This happened only when
153        the reset was to the original external option setting. (An optimization
154        abstracts leading options settings into an external setting, which was the
155        cause of this.)
157    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
158        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
159        assertion pattern did not match (meaning that the assertion was true), it
160        was incorrectly treated as false if the SKIP had been reached during the
161        matching. This also applied to assertions used as conditions.
163    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
164        assertion subpattern, including such a pattern used as a condition,
165        unpredictable results occurred, instead of the error return
168    5.  The C++ GlobalReplace function was not working like Perl for the special
169        situation when an empty string is matched. It now does the fancy magic
170        stuff that is necessary.
172    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
173        removed. (These were left over from very, very early versions of PCRE.)
175    7.  Some cosmetic changes to the code to make life easier when compiling it
176        as part of something else:
178        (a) Change DEBUG to PCRE_DEBUG.
180        (b) In pcre_compile(), rename the member of the "branch_chain" structure
181            called "current" as "current_branch", to prevent a collision with the
182            Linux macro when compiled as a kernel module.
184        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
185            prevent a collision with the Linux macro when compiled as a kernel
186            module.
188    8.  In pcre_compile() there are some checks for integer overflows that used to
189        cast potentially large values to (double). This has been changed to that
190        when building, a check for int64_t is made, and if it is found, it is used
191        instead, thus avoiding the use of floating point arithmetic. (There is no
192        other use of FP in PCRE.) If int64_t is not found, the fallback is to
193        double.
195    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
196        2005 (difference between two addresses compared to an unsigned value).
198    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
199        custom one, because of the following reported problem in Windows:
201          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
202              under Win32.
203          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
204              therefore missing the function definition.
205          - The compiler thus generates a "C" signature for the test function.
206          - The linker fails to find the "C" function.
207          - PCRE fails to configure if asked to do so against libbz2.
209    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
210        messages were output:
212          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
213          rerunning libtoolize, to keep the correct libtool macros in-tree.
214          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
216        I have done both of these things.
218    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
219        most of the time, it *can* run out if it is given a pattern that contains a
220        runaway infinite recursion. I updated the discussion in the pcrestack man
221        page.
223    13. Now that we have gone to the x.xx style of version numbers, the minor
224        version may start with zero. Using 08 or 09 is a bad idea because users
225        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
226        interpreted as invalid octal numbers. I've updated the previous comment in
227        configure.ac, and also added a check that gives an error if 08 or 09 are
228        used.
230    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
231        causing partial matching to fail when the end of the subject matched \W
232        in a UTF-8 pattern where \W was quantified with a minimum of 3.
234    15. There were some discrepancies between the declarations in pcre_internal.h
235        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
236        their definitions. The declarations used "const uschar *" and the
237        definitions used USPTR. Even though USPTR is normally defined as "const
238        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
239        reported that: "This difference in casting confuses some C++ compilers, for
240        example, SunCC recognizes above declarations as different functions and
241        generates broken code for hbpcre." I have changed the declarations to use
242        USPTR.
244    16. GNU libtool is named differently on some systems. The autogen.sh script now
245        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
246        (FreeBSD).
248    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
249        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
250        comment: "Figure out how to create a longlong from a string: strtoll and
251        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
252        instance, but it only takes 2 args instead of 3!"
254    18. A subtle bug concerned with back references has been fixed by a change of
255        specification, with a corresponding code fix. A pattern such as
256        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
257        refers, was giving matches when it shouldn't. For example, xa=xaaa would
258        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
259        same bug. Such groups have to be quantified to be useful, or contained
260        inside another quantified group. (If there's no repetition, the reference
261        can never match.) The problem arises because, having left the group and
262        moved on to the rest of the pattern, a later failure that backtracks into
263        the group uses the captured value from the final iteration of the group
264        rather than the correct earlier one. I have fixed this in PCRE by forcing
265        any group that contains a reference to itself to be an atomic group; that
266        is, there cannot be any backtracking into it once it has completed. This is
267        similar to recursive and subroutine calls.
270    Version 8.00 19-Oct-09
271    ----------------------
273    1.  The table for translating pcre_compile() error codes into POSIX error codes
274        was out-of-date, and there was no check on the pcre_compile() error code
275        being within the table. This could lead to an OK return being given in
276        error.
278    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
279        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
280        in a Windows environment.
282    3.  The pcregrep --count option prints the count for each file even when it is
283        zero, as does GNU grep. However, pcregrep was also printing all files when
284        --files-with-matches was added. Now, when both options are given, it prints
285        counts only for those files that have at least one match. (GNU grep just
286        prints the file name in this circumstance, but including the count seems
287        more useful - otherwise, why use --count?) Also ensured that the
288        combination -clh just lists non-zero counts, with no names.
290    4.  The long form of the pcregrep -F option was incorrectly implemented as
291        --fixed_strings instead of --fixed-strings. This is an incompatible change,
292        but it seems right to fix it, and I didn't think it was worth preserving
293        the old behaviour.
295    5.  The command line items --regex=pattern and --regexp=pattern were not
296        recognized by pcregrep, which required --regex pattern or --regexp pattern
297        (with a space rather than an '='). The man page documented the '=' forms,
298        which are compatible with GNU grep; these now work.
300    6.  No libpcreposix.pc file was created for pkg-config; there was just
301        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
303    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
304        when UCP support is not needed, by modifying the Python script that
305        generates it from Unicode data files. This should not matter if the module
306        is correctly used as a library, but I received one complaint about 50K of
307        unwanted data. My guess is that the person linked everything into his
308        program rather than using a library. Anyway, it does no harm.
310    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
311        was a minimum greater than 1 for a wide character in a possessive
312        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
313        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
314        character. Chaos in the form of incorrect output or a compiling loop could
315        result.
317    9.  The restrictions on what a pattern can contain when partial matching is
318        requested for pcre_exec() have been removed. All patterns can now be
319        partially matched by this function. In addition, if there are at least two
320        slots in the offset vector, the offset of the earliest inspected character
321        for the match and the offset of the end of the subject are set in them when
322        PCRE_ERROR_PARTIAL is returned.
324    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
325        synonymous with PCRE_PARTIAL, for backwards compatibility, and
326        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
327        and may be more useful for multi-segment matching.
329    11. Partial matching with pcre_exec() is now more intuitive. A partial match
330        used to be given if ever the end of the subject was reached; now it is
331        given only if matching could not proceed because another character was
332        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
333        string "Z", which now yields "no match" instead of "partial match". In the
334        case of pcre_dfa_exec(), "no match" is given if every matching path for the
335        final character ended with (*FAIL).
337    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
338        if the pattern had a "must contain" character that was already found in the
339        earlier partial match, unless partial matching was again requested. For
340        example, with the pattern /dog.(body)?/, the "must contain" character is
341        "g". If the first part-match was for the string "dog", restarting with
342        "sbody" failed. This bug has been fixed.
344    13. The string returned by pcre_dfa_exec() after a partial match has been
345        changed so that it starts at the first inspected character rather than the
346        first character of the match. This makes a difference only if the pattern
347        starts with a lookbehind assertion or \b or \B (\K is not supported by
348        pcre_dfa_exec()). It's an incompatible change, but it makes the two
349        matching functions compatible, and I think it's the right thing to do.
351    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
352        so that the demonstration program is easily available in environments where
353        PCRE has not been installed from source.
355    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
356        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
357        library.
359    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
360        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
361        is not the first non-POSIX option to be added. Clearly some people find
362        these options useful.
364    17. If a caller to the POSIX matching function regexec() passes a non-zero
365        value for nmatch with a NULL value for pmatch, the value of
366        nmatch is forced to zero.
368    18. RunGrepTest did not have a test for the availability of the -u option of
369        the diff command, as RunTest does. It now checks in the same way as
370        RunTest, and also checks for the -b option.
372    19. If an odd number of negated classes containing just a single character
373        interposed, within parentheses, between a forward reference to a named
374        subpattern and the definition of the subpattern, compilation crashed with
375        an internal error, complaining that it could not find the referenced
376        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
377        [The bug was that it was starting one character too far in when skipping
378        over the character class, thus treating the ] as data rather than
379        terminating the class. This meant it could skip too much.]
381    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
382        /g option in pcretest when the pattern contains \K, which makes it possible
383        to have an empty string match not at the start, even when the pattern is
384        anchored. Updated pcretest and pcredemo to use this option.
386    21. If the maximum number of capturing subpatterns in a recursion was greater
387        than the maximum at the outer level, the higher number was returned, but
388        with unset values at the outer level. The correct (outer level) value is
389        now given.
391    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
392        PCRE did not set those parentheses (unlike Perl). I have now found a way to
393        make it do so. The string so far is captured, making this feature
394        compatible with Perl.
396    23. The tests have been re-organized, adding tests 11 and 12, to make it
397        possible to check the Perl 5.10 features against Perl 5.10.
399    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
400        pattern matches a fixed length string. PCRE did not allow this; now it
401        does. Neither allows recursion.
403    25. I finally figured out how to implement a request to provide the minimum
404        length of subject string that was needed in order to match a given pattern.
405        (It was back references and recursion that I had previously got hung up
406        on.) This code has now been added to pcre_study(); it finds a lower bound
407        to the length of subject needed. It is not necessarily the greatest lower
408        bound, but using it to avoid searching strings that are too short does give
409        some useful speed-ups. The value is available to calling programs via
410        pcre_fullinfo().
412    26. While implementing 25, I discovered to my embarrassment that pcretest had
413        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
414        study optimizations had never been tested with that matching function.
415        Oops. What is worse, even when it was passed study data, there was a bug in
416        pcre_dfa_exec() that meant it never actually used it. Double oops. There
417        were also very few tests of studied patterns with pcre_dfa_exec().
419    27. If (?| is used to create subpatterns with duplicate numbers, they are now
420        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
421        on the other side of the coin, they are no longer allowed to have different
422        names, because these cannot be distinguished in PCRE, and this has caused
423        confusion. (This is a difference from Perl.)
425    28. When duplicate subpattern names are present (necessarily with different
426        numbers, as required by 27 above), and a test is made by name in a
427        conditional pattern, either for a subpattern having been matched, or for
428        recursion in such a pattern, all the associated numbered subpatterns are
429        tested, and the overall condition is true if the condition is true for any
430        one of them. This is the way Perl works, and is also more like the way
431        testing by number works.
434    Version 7.9 11-Apr-09
435    ---------------------
437    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
438        (pcretest), all targets were linked against these libraries. This included
439        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
440        libraries. This caused unwanted dependencies to be created. This problem
441        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
442        pcretest is linked with readline.
444    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
445        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
446        moved outside it again, because FALSE and TRUE are already defined in AIX,
447        but BOOL is not.
449    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
450        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
452    4.  The pcregrep documentation said spaces were inserted as well as colons (or
453        hyphens) following file names and line numbers when outputting matching
454        lines. This is not true; no spaces are inserted. I have also clarified the
455        wording for the --colour (or --color) option.
457    5.  In pcregrep, when --colour was used with -o, the list of matching strings
458        was not coloured; this is different to GNU grep, so I have changed it to be
459        the same.
461    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
462        each matching line was coloured. Now it goes on to look for further matches
463        of any of the test patterns, which is the same behaviour as GNU grep.
465    7.  A pattern that could match an empty string could cause pcregrep to loop; it
466        doesn't make sense to accept an empty string match in pcregrep, so I have
467        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
468        seems to be how GNU grep behaves.
470    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
471        start or after a newline", because the conditional assertion was not being
472        correctly handled. The rule now is that both the assertion and what follows
473        in the first alternative must satisfy the test.
475    9.  If auto-callout was enabled in a pattern with a conditional group whose
476        condition was an assertion, PCRE could crash during matching, both with
477        pcre_exec() and pcre_dfa_exec().
479    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
480        used for matching.
482    11. Unicode property support in character classes was not working for
483        characters (bytes) greater than 127 when not in UTF-8 mode.
485    12. Added the -M command line option to pcretest.
487    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
489    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
491    16. Added comments and documentation about mis-use of no_arg in the C++
492        wrapper.
494    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
495        from Martin Jerabek that uses macro names for all relevant character and
496        string constants.
498    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
499        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
500        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
501        these, but not everybody uses configure.
503    19. A conditional group that had only one branch was not being correctly
504        recognized as an item that could match an empty string. This meant that an
505        enclosing group might also not be so recognized, causing infinite looping
506        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
507        with the subject "ab", where knowledge that the repeated group can match
508        nothing is needed in order to break the loop.
510    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
511        exec(), but without supplying a callout function, matching went wrong.
513    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
514        leak if the size of the offset vector was greater than 30. When the vector
515        is smaller, the saved offsets during recursion go onto a local stack
516        vector, but for larger vectors malloc() is used. It was failing to free
517        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
518        error, in fact).
520    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
521        heapframe that is used only when UTF-8 support is enabled. This caused no
522        problem, but was untidy.
524    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
525        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
526        included within another project.
528    24. Steven Van Ingelgem's patches to add more options to the CMake support,
529        slightly modified by me:
531          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
532              not building pcregrep.
534          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
535              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
537    25. Forward references, both numeric and by name, in patterns that made use of
538        duplicate group numbers, could behave incorrectly or give incorrect errors,
539        because when scanning forward to find the reference group, PCRE was not
540        taking into account the duplicate group numbers. A pattern such as
541        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
543    26. Changed a few more instances of "const unsigned char *" to USPTR, making
544        the feature of a custom pointer more persuasive (as requested by a user).
546    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
547        pcretest.c, inside #ifndefs, because it seems they are sometimes already
548        pre-defined.
550    28. Added support for (*UTF8) at the start of a pattern.
552    29. Arrange for flags added by the "release type" setting in CMake to be shown
553        in the configuration summary.
556    Version 7.8 05-Sep-08
557    ---------------------
559    1.  Replaced UCP searching code with optimized version as implemented for Ad
560        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
561        stage table and inline lookup instead of a function, giving speed ups of 2
562        to 5 times on some simple patterns that I tested. Permission was given to
563        distribute the MultiStage2.py script that generates the tables (it's not in
564        the tarball, but is in the Subversion repository).
566    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
567        scripts.
569    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
570        a group with a zero qualifier. The result of the study could be incorrect,
571        or the function might crash, depending on the pattern.
573    4.  Caseless matching was not working for non-ASCII characters in back
574        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
575        It now works when Unicode Property Support is available.
577    5.  In pcretest, an escape such as \x{de} in the data was always generating
578        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
579        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
580        truncation.
582    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
584    7.  Added two (int) casts to pcregrep when printing the difference of two
585        pointers, in case they are 64-bit values.
587    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
588        test 2 if it fails.
590    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
591        and a #define of that name to empty if it is not externally set. This is to
592        allow users of MSVC to set it if necessary.
594    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
595        the convenience functions in the pcre_get.c source file.
597    11. An option change at the start of a pattern that had top-level alternatives
598        could cause overwriting and/or a crash. This command provoked a crash in
599        some environments:
601          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
603        This potential security problem was recorded as CVE-2008-2371.
605    12. For a pattern where the match had to start at the beginning or immediately
606        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
607        pcre_dfa_exec() could read past the end of the passed subject if there was
608        no match. To help with detecting such bugs (e.g. with valgrind), I modified
609        pcretest so that it places the subject at the end of its malloc-ed buffer.
611    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
612        exec() might read past the end of the data buffer in UTF-8 mode.
614    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
615        the data contained the byte 0x85 as part of a UTF-8 character within its
616        first line. This applied both to normal and DFA matching.
618    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
619        /^[^d]*?$/8 failed to match "abc".
621    16. Added a missing copyright notice to pcrecpp_internal.h.
623    17. Make it more clear in the documentation that values returned from
624        pcre_exec() in ovector are byte offsets, not character counts.
626    18. Tidied a few places to stop certain compilers from issuing warnings.
628    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
629        supplied by Stefan Weber. I made a further small update for 7.8 because
630        there is a change of source arrangements: the pcre_searchfuncs.c module is
631        replaced by pcre_ucd.c.
634    Version 7.7 07-May-08
635    ---------------------
637    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
638        a string to a long long, pretend we don't even have a long long." This is
639        done by checking for the strtoq, strtoll, and _strtoi64 functions.
641    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
642        pre-7.6 versions, which defined a global no_arg variable instead of putting
643        it in the RE class. (See also #8 below.)
645    3.  Remove a line of dead code, identified by coverity and reported by Nuno
646        Lopes.
648    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
650        (1) The include/exclude patterns were being applied to the whole pathnames
651            of files, instead of just to the final components.
653        (2) If there was more than one level of directory, the subdirectories were
654            skipped unless they satisfied the include/exclude conditions. This is
655            inconsistent with GNU grep (and could even be seen as contrary to the
656            pcregrep specification - which I improved to make it absolutely clear).
657            The action now is always to scan all levels of directory, and just
658            apply the include/exclude patterns to regular files.
660    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
661        --exclude_dir in the tests to avoid scanning .svn directories.
663    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
664        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
665        doesn't support NULs in patterns.
667    7.  Added some missing "const"s to declarations of static tables in
668        pcre_compile.c and pcre_dfa_exec.c.
670    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
671        caused by fix #2  above. (Subsequently also a second patch to fix the
672        first patch. And a third patch - this was a messy problem.)
674    9.  Applied Craig's patch to remove the use of push_back().
676    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
677        matching function regexec().
679    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
680        which, however, unlike Perl's \g{...}, are subroutine calls, not back
681        references. PCRE supports relative numbers with this syntax (I don't think
682        Oniguruma does).
684    12. Previously, a group with a zero repeat such as (...){0} was completely
685        omitted from the compiled regex. However, this means that if the group
686        was called as a subroutine from elsewhere in the pattern, things went wrong
687        (an internal error was given). Such groups are now left in the compiled
688        pattern, with a new opcode that causes them to be skipped at execution
689        time.
691    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
692        to the way PCRE behaves:
694        (a) A lone ] character is dis-allowed (Perl treats it as data).
696        (b) A back reference to an unmatched subpattern matches an empty string
697            (Perl fails the current match path).
699        (c) A data ] in a character class must be notated as \] because if the
700            first data character in a class is ], it defines an empty class. (In
701            Perl it is not possible to have an empty class.) The empty class []
702            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
703            The negative empty class [^] matches any one character, independently
704            of the DOTALL setting.
706    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
707        non-existent subpattern following a character class starting with ']' and
708        containing () gave an internal compiling error instead of "reference to
709        non-existent subpattern". Fortunately, when the pattern did exist, the
710        compiled code was correct. (When scanning forwards to check for the
711        existencd of the subpattern, it was treating the data ']' as terminating
712        the class, so got the count wrong. When actually compiling, the reference
713        was subsequently set up correctly.)
715    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
716        it was being rejected as not supported by pcre_dfa_exec(), even though
717        other assertions are supported. I have made pcre_dfa_exec() support
718        (*FAIL).
720    16. The implementation of 13c above involved the invention of a new opcode,
721        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
722        cannot be changed at match time, I realized I could make a small
723        improvement to matching performance by compiling OP_ALLANY instead of
724        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
725        on the OP_ANY path.
727    17. Compiling pcretest on Windows with readline support failed without the
728        following two fixes: (1) Make the unistd.h include conditional on
729        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
731    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
732        ncurses library to be included for pcretest when ReadLine support is
733        requested, but also to allow for it to be overridden. This patch came from
734        Daniel Bergström.
736    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
737        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
738        any errors with the current Unicode tables. Thanks to Peter Kankowski for
739        spotting this.
742    Version 7.6 28-Jan-08
743    ---------------------
745    1.  A character class containing a very large number of characters with
746        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
747        overflow.
749    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
750        HAVE_LONG_LONG is not defined.
752    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
753        bring them up to date and include new features. This patch includes:
755        - Fixed PH's badly added libz and libbz2 support.
756        - Fixed a problem with static linking.
757        - Added pcredemo. [But later removed - see 7 below.]
758        - Fixed dftables problem and added an option.
759        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
760            HAVE_LONG_LONG.
761        - Added readline support for pcretest.
762        - Added an listing of the option settings after cmake has run.
764    4.  A user submitted a patch to Makefile that makes it easy to create
765        "pcre.dll" under mingw when using Configure/Make. I added stuff to
766        Makefile.am that cause it to include this special target, without
767        affecting anything else. Note that the same mingw target plus all
768        the other distribution libraries and programs are now supported
769        when configuring with CMake (see 6 below) instead of with
770        Configure/Make.
772    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
773        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
774        exported in the Windows port". It has not yet been confirmed that the patch
775        solves the problem, but it does no harm.
777    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
778        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
779        with CMake, and also correct the comment about stack recursion.
781    7.  Remove the automatic building of pcredemo from the ./configure system and
782        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
783        of a program that users should build themselves after PCRE is installed, so
784        building it automatically is not really right. What is more, it gave
785        trouble in some build environments.
787    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
790    Version 7.5 10-Jan-08
791    ---------------------
793    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
794        values in parens when parsing an RE using the C++ wrapper."
796    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
797        Characters greater than 255 were excluded from the class instead of being
798        included.
800    3.  The same bug as (2) above applied to negated POSIX classes such as
801        [:^space:].
803    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
804        defined or documented. It seems to have been a typo for PCRE_STATIC, so
805        I have changed it.
807    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
808        first named subpattern) and a construct such as (?&a) would reference the
809        first named subpattern whose name started with "a" (in other words, the
810        length check was missing). Both these problems are fixed. "Subpattern name
811        expected" is now given for (?&) (a zero-length name), and this patch also
812        makes it give the same error for \k'' (previously it complained that that
813        was a reference to a non-existent subpattern).
815    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
816        this is right because (?- can be followed by option settings as well as by
817        digits. I have, however, made the messages clearer.
819    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
820        than the number used in the conditional) now cause a compile-time error.
821        This is actually not compatible with Perl, which accepts such patterns, but
822        treats the conditional as always being FALSE (as PCRE used to), but it
823        seems to me that giving a diagnostic is better.
825    8.  Change "alphameric" to the more common word "alphanumeric" in comments
826        and messages.
828    9.  Fix two occurrences of "backslash" in comments that should have been
829        "backspace".
831    10. Remove two redundant lines of code that can never be obeyed (their function
832        was moved elsewhere).
834    11. The program that makes PCRE's Unicode character property table had a bug
835        which caused it to generate incorrect table entries for sequences of
836        characters that have the same character type, but are in different scripts.
837        It amalgamated them into a single range, with the script of the first of
838        them. In other words, some characters were in the wrong script. There were
839        thirteen such cases, affecting characters in the following ranges:
841          U+002b0 - U+002c1
842          U+0060c - U+0060d
843          U+0061e - U+00612
844          U+0064b - U+0065e
845          U+0074d - U+0076d
846          U+01800 - U+01805
847          U+01d00 - U+01d77
848          U+01d9b - U+01dbf
849          U+0200b - U+0200f
850          U+030fc - U+030fe
851          U+03260 - U+0327f
852          U+0fb46 - U+0fbb1
853          U+10450 - U+1049d
855    12. The -o option (show only the matching part of a line) for pcregrep was not
856        compatible with GNU grep in that, if there was more than one match in a
857        line, it showed only the first of them. It now behaves in the same way as
858        GNU grep.
860    13. If the -o and -v options were combined for pcregrep, it printed a blank
861        line for every non-matching line. GNU grep prints nothing, and pcregrep now
862        does the same. The return code can be used to tell if there were any
863        non-matching lines.
865    14. Added --file-offsets and --line-offsets to pcregrep.
867    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
868        infinitely looping recursion. The bug was that positive lookaheads were not
869        being skipped when checking for a possible empty match (negative lookaheads
870        and both kinds of lookbehind were skipped).
872    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
873        inclusion of <windows.h> to before rather than after the definition of
874        INVALID_FILE_ATTRIBUTES (patch from David Byron).
876    17. Specifying a possessive quantifier with a specific limit for a Unicode
877        character property caused pcre_compile() to compile bad code, which led at
878        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
879        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
880        caused the error; without that there was no problem.
882    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
884    19. Added --enable-pcretest-libreadline.
886    20. In pcrecpp.cc, the variable 'count' was incremented twice in
887        RE::GlobalReplace(). As a result, the number of replacements returned was
888        double what it should be. I removed one of the increments, but Craig sent a
889        later patch that removed the other one (the right fix) and added unit tests
890        that check the return values (which was not done before).
892    21. Several CMake things:
894        (1) Arranged that, when cmake is used on Unix, the libraries end up with
895            the names libpcre and libpcreposix, not just pcre and pcreposix.
897        (2) The above change means that pcretest and pcregrep are now correctly
898            linked with the newly-built libraries, not previously installed ones.
902    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
903        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
904        UTF-8 newline character). The key issue is that the pattern starts .*;
905        this means that the match must be either at the beginning, or after a
906        newline. The bug was in the code for advancing after a failed match and
907        checking that the new position followed a newline. It was not taking
908        account of UTF-8 characters correctly.
910    23. PCRE was behaving differently from Perl in the way it recognized POSIX
911        character classes. PCRE was not treating the sequence [:...:] as a
912        character class unless the ... were all letters. Perl, however, seems to
913        allow any characters between [: and :], though of course it rejects as
914        unknown any "names" that contain non-letters, because all the known class
915        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
916        for example, whereas PCRE did not - it did not recognize a POSIX character
917        class. This seemed a bit dangerous, so the code has been changed to be
918        closer to Perl. The behaviour is not identical to Perl, because PCRE will
919        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
920        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
921        Perl does, and where it didn't before.
923    24. Rewrite so as to remove the single use of %n from pcregrep because in some
924        Windows environments %n is disabled by default.
927    Version 7.4 21-Sep-07
928    ---------------------
930    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
931        means that a class such as [\s] counted as "explicit reference to CR or
932        LF". That isn't really right - the whole point of the change was to try to
933        help when there was an actual mention of one of the two characters. So now
934        the change happens only if \r or \n (or a literal CR or LF) character is
935        encountered.
937    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
938        of both had grown to the point where there were only 3 bits left.
939        Fortunately, there was spare space in the data structure, and so I have
940        moved the internal flags into a new 16-bit field to free up more option
941        bits.
943    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
944        but did not set the internal JCHANGED flag - either of these is enough to
945        control the way the "get" function works - but the PCRE_INFO_JCHANGED
946        facility is supposed to tell if (?J) was ever used, so now (?J) at the
947        start sets both bits.
949    4.  Added options (at build time, compile time, exec time) to change \R from
950        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
952    5.  doc/pcresyntax.html was missing from the distribution.
954    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
955        compatibility, even though it is no longer used.
957    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
958        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
959        windows.h file is present (where different names are used). [This was
960        reversed later after testing - see 16 below.]
962    8.  Changed all #include <config.h> to #include "config.h". There were also
963        some further <pcre.h> cases that I changed to "pcre.h".
965    9.  When pcregrep was used with the --colour option, it missed the line ending
966        sequence off the lines that it output.
968    10. It was pointed out to me that arrays of string pointers cause lots of
969        relocations when a shared library is dynamically loaded. A technique of
970        using a single long string with a table of offsets can drastically reduce
971        these. I have refactored PCRE in four places to do this. The result is
972        dramatic:
974          Originally:                          290
975          After changing UCP table:            187
976          After changing error message table:   43
977          After changing table of "verbs"       36
978          After changing table of Posix names   22
980        Thanks to the folks working on Gregex for glib for this insight.
982    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
983        unicode-properties was also set.
985    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
987    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
988        checked only for CRLF.
990    14. Added casts to pcretest.c to avoid compiler warnings.
992    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
994    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
995        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
996        entirely. This removes changes made in 7 above.
998    17. The CMake files have been updated, and there is now more information about
999        building with CMake in the NON-UNIX-USE document.
1002    Version 7.3 28-Aug-07
1003    ---------------------
1005     1. In the rejigging of the build system that eventually resulted in 7.1, the
1006        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1007        brackets there is not right, since it causes compilers to look for an
1008        installed pcre.h, not the version that is in the source that is being
1009        compiled (which of course may be different). I have changed it back to:
1011          #include "pcre.h"
1013        I have a vague recollection that the change was concerned with compiling in
1014        different directories, but in the new build system, that is taken care of
1015        by the VPATH setting the Makefile.
1017     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1018        when the subject happened to end in the byte 0x85 (e.g. if the last
1019        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1020        characters but of course it shouldn't be taken as a newline when it is part
1021        of another character. The bug was that, for an unlimited repeat of . in
1022        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1023        characters when looking for a newline.
1025     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1027     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1028        in debug output.
1030     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1031        long printing in the pcrecpp unittest when running under MinGW.
1033     6. ESC_K was left out of the EBCDIC table.
1035     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1036        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1037        limit also applies to "virtual nesting" when a pattern is recursive, and in
1038        this case 1000 isn't so big. I have been able to remove this limit at the
1039        expense of backing off one optimization in certain circumstances. Normally,
1040        when pcre_exec() would call its internal match() function recursively and
1041        immediately return the result unconditionally, it uses a "tail recursion"
1042        feature to save stack. However, when a subpattern that can match an empty
1043        string has an unlimited repetition quantifier, it no longer makes this
1044        optimization. That gives it a stack frame in which to save the data for
1045        checking that an empty string has been matched. Previously this was taken
1046        from the 1000-entry workspace that had been reserved. So now there is no
1047        explicit limit, but more stack is used.
1049     8. Applied Daniel's patches to solve problems with the import/export magic
1050        syntax that is required for Windows, and which was going wrong for the
1051        pcreposix and pcrecpp parts of the library. These were overlooked when this
1052        problem was solved for the main library.
1054     9. There were some crude static tests to avoid integer overflow when computing
1055        the size of patterns that contain repeated groups with explicit upper
1056        limits. As the maximum quantifier is 65535, the maximum group length was
1057        set at 30,000 so that the product of these two numbers did not overflow a
1058        32-bit integer. However, it turns out that people want to use groups that
1059        are longer than 30,000 bytes (though not repeat them that many times).
1060        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1061        made it possible to implement the integer overflow checks in a much more
1062        dynamic way, which I have now done. The artificial limitation on group
1063        length has been removed - we now have only the limit on the total length of
1064        the compiled pattern, which depends on the LINK_SIZE setting.
1066    10. Fixed a bug in the documentation for get/copy named substring when
1067        duplicate names are permitted. If none of the named substrings are set, the
1068        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1069        empty string.
1071    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1072        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1073        because the ] is interpreted as the first data character and the
1074        terminating ] is not found. PCRE has been made compatible with Perl in this
1075        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1076        cause memory overwriting.
1078    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1079        string has been matched (to stop an infinite loop). It was not recognizing
1080        a conditional subpattern that could match an empty string if that
1081        subpattern was within another subpattern. For example, it looped when
1082        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1083        condition was not nested. This bug has been fixed.
1085    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1086        past the start of the subject in the presence of bytes with the top bit
1087        set, for example "\x8aBCD".
1089    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1090        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1092    14. Optimized (?!) to (*FAIL).
1094    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1095        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1096        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1097        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1098        does: it's just the validity check that is more restrictive.
1100    16. Inserted checks for integer overflows during escape sequence (backslash)
1101        processing, and also fixed erroneous offset values for syntax errors during
1102        backslash processing.
1104    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1105        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1107    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1108        caused an overrun.
1110    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1111        something other than just ASCII characters) inside a group that had an
1112        unlimited repeat caused a loop at compile time (while checking to see
1113        whether the group could match an empty string).
1115    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1116        [\P{Any}] did so. (Error in the code for printing property names.)
1118    21. An orphan \E inside a character class could cause a crash.
1120    22. A repeated capturing bracket such as (A)? could cause a wild memory
1121        reference during compilation.
1123    23. There are several functions in pcre_compile() that scan along a compiled
1124        expression for various reasons (e.g. to see if it's fixed length for look
1125        behind). There were bugs in these functions when a repeated \p or \P was
1126        present in the pattern. These operators have additional parameters compared
1127        with \d, etc, and these were not being taken into account when moving along
1128        the compiled data. Specifically:
1130        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1131            length.
1133        (b) An item such as \pL+ within a repeated group could cause crashes or
1134            loops.
1136        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1137            "reference to non-existent subpattern" error.
1139        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1141    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1142        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1144    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1146    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1147        character were causing crashes (broken optimization).
1149    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1150        \p or \P) caused a compile-time loop.
1152    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1153        break. For example, the unstudied pattern [\r\n]A does not match the string
1154        "\r\nA" because change 7.0/46 below moves the current point on by two
1155        characters after failing to match at the start. However, the pattern \nA
1156        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1157        the same is true. There doesn't seem any very clean way out of this, but
1158        what I have chosen to do makes the common cases work: PCRE now takes note
1159        of whether there can be an explicit match for \r or \n anywhere in the
1160        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1161        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1162        pattern has explicit CR or LF references.
1164    29. Added (*CR) etc for changing newline setting at start of pattern.
1167    Version 7.2 19-Jun-07
1168    ---------------------
1170     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1171        which is apparently normally available under Windows.
1173     2. Re-jig the pcregrep tests with different newline settings in an attempt
1174        to make them independent of the local environment's newline setting.
1176     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1178     4. Some of the "internals" tests were previously cut out when the link size
1179        was not 2, because the output contained actual offsets. The recent new
1180        "Z" feature of pcretest means that these can be cut out, making the tests
1181        usable with all link sizes.
1183     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1184        stack recursion. This gives a massive performance boost under BSD, but just
1185        a small improvement under Linux. However, it saves one field in the frame
1186        in all cases.
1188     6. Added more features from the forthcoming Perl 5.10:
1190        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1191            recursion call. It refers to the nth most recently opened parentheses.
1193        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1194            to be opened parentheses.
1196        (c) Conditions that refer to capturing parentheses can be specified
1197            relatively, for example, (?(-2)... or (?(+3)...
1199        (d) \K resets the start of the current match so that everything before
1200            is not part of it.
1202        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1204        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1205            reference syntax.
1207        (g) (?| introduces a group in which the numbering of parentheses in each
1208            alternative starts with the same number.
1210        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1212     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1215     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1216        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1217        for detecting groups that can match an empty string.
1219     9. A pattern with a very large number of alternatives (more than several
1220        hundred) was running out of internal workspace during the pre-compile
1221        phase, where pcre_compile() figures out how much memory will be needed. A
1222        bit of new cunning has reduced the workspace needed for groups with
1223        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1224        workspace instead of running out of the 4096 that are available.
1226    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1228    11. Applied patch from Google to remove an optimization that didn't quite work.
1229        The report of the bug said:
1231          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1232          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1233          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1235    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1236        it matched the wrong number of bytes.
1239    Version 7.1 24-Apr-07
1240    ---------------------
1242     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1243        that is more "standard", making use of automake and other Autotools. There
1244        is some re-arrangement of the files and adjustment of comments consequent
1245        on this.
1247     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1248        for recursive directory scanning broke on some systems because the files
1249        are not scanned in any specific order and on different systems the order
1250        was different. A call to "sort" has been inserted into RunGrepTest for the
1251        approprate test as a short-term fix. In the longer term there may be an
1252        alternative.
1254     3. I had an email from Eric Raymond about problems translating some of PCRE's
1255        man pages to HTML (despite the fact that I distribute HTML pages, some
1256        people do their own conversions for various reasons). The problems
1257        concerned the use of low-level troff macros .br and .in. I have therefore
1258        removed all such uses from the man pages (some were redundant, some could
1259        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1260        HTML has been updated to handle .nf/.fi and to complain if it encounters
1261        .br or .in.
1263     4. Updated comments in configure.ac that get placed in config.h.in and also
1264        arranged for config.h to be included in the distribution, with the name
1265        config.h.generic, for the benefit of those who have to compile without
1266        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1268     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1269        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1270        makevp.bat for the current PCRE, using the additional files
1271        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1273     6. A Windows user reported a minor discrepancy with test 2, which turned out
1274        to be caused by a trailing space on an input line that had got lost in his
1275        copy. The trailing space was an accident, so I've just removed it.
1277     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1278        that is needed.
1280     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1281        as "const" (a) because they are and (b) because it helps the PHP
1282        maintainers who have recently made a script to detect big data structures
1283        in the php code that should be moved to the .rodata section. I remembered
1284        to update Builducptable as well, so it won't revert if ucptable.h is ever
1285        re-created.
1287     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1288        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1289        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1290        support is not required. This saves 1.5-2K of code, which is important in
1291        some applications.
1293        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1294        so as not to refer to the tables, even though these functions will never be
1295        called when UTF-8 support is disabled. Otherwise there are problems with a
1296        shared library.
1298    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1300        (a) It was defining its arguments as char * instead of void *.
1302        (b) It was assuming that all moves were upwards in memory; this was true
1303            a long time ago when I wrote it, but is no longer the case.
1305        The emulated memove() is provided for those environments that have neither
1306        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1307        is clearly not the case, as these two bugs were recently reported.
1309    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1310        and Detrail to create the HTML documentation, the .txt form of the man
1311        pages, and it removes trailing spaces from listed files. It also creates
1312        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1313        case, it wraps all the #defines with #ifndefs. This script should be run
1314        before "make dist".
1316    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1317        with Unicode property support.
1319        (a) For a maximizing quantifier, if the two different cases of the
1320            character were of different lengths in their UTF-8 codings (there are
1321            some cases like this - I found 11), and the matching function had to
1322            back up over a mixture of the two cases, it incorrectly assumed they
1323            were both the same length.
1325        (b) When PCRE was configured to use the heap rather than the stack for
1326            recursion during matching, it was not correctly preserving the data for
1327            the other case of a UTF-8 character when checking ahead for a match
1328            while processing a minimizing repeat. If the check also involved
1329            matching a wide character, but failed, corruption could cause an
1330            erroneous result when trying to check for a repeat of the original
1331            character.
1333    13. Some tidying changes to the testing mechanism:
1335        (a) The RunTest script now detects the internal link size and whether there
1336            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1337            values substituted by "configure". (The RunGrepTest script already did
1338            this for UTF-8.) The configure.ac script no longer substitutes the
1339            relevant variables.
1341        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1342            with length and offset values. This means that the output is different
1343            for different internal link sizes. Test 2 is skipped for link sizes
1344            other than 2 because of this, bypassing the problem. Unfortunately,
1345            there was also a test in test 3 (the locale tests) that used /B and
1346            failed for link sizes other than 2. Rather than cut the whole test out,
1347            I have added a new /Z option to pcretest that replaces the length and
1348            offset values with spaces. This is now used to make test 3 independent
1349            of link size. (Test 2 will be tidied up later.)
1351    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1352        segmentation fault instead of returning the appropriate error message.
1354    15. In multiline mode when the newline sequence was set to "any", the pattern
1355        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1356        This doesn't seem right; it now treats the CRLF combination as the line
1357        ending, and so does not match in that case. It's only a pattern such as ^$
1358        that would hit this one: something like ^ABC$ would have failed after \r
1359        and then tried again after \r\n.
1361    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1362        in an attempt to make files that differ only in their line terminators
1363        compare equal. This works on Linux.
1365    17. Under certain error circumstances pcregrep might try to free random memory
1366        as it exited. This is now fixed, thanks to valgrind.
1368    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1369        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1370        was because its rules for how to advance for /g after matching an empty
1371        string at the end of a line did not allow for this case. They now check for
1372        it specially.
1374    20. pcretest is supposed to handle patterns and data of any length, by
1375        extending its buffers when necessary. It was getting this wrong when the
1376        buffer for a data line had to be extended.
1378    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1379        CRLF as a newline sequence.
1381    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1382        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1383        I have nevertheless tidied it up.
1385    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1387    24. Added a man page for pcre-config.
1390    Version 7.0 19-Dec-06
1391    ---------------------
1393     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1394        moving to gcc 4.1.1.
1396     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1397        sys/time.h, which is documented as needed for this function. It doesn't
1398        seem to matter on Linux, but it showed up on some releases of OS X.
1400     3. It seems that there are systems where bytes whose values are greater than
1401        127 match isprint() in the "C" locale. The "C" locale should be the
1402        default when a C program starts up. In most systems, only ASCII printing
1403        characters match isprint(). This difference caused the output from pcretest
1404        to vary, making some of the tests fail. I have changed pcretest so that:
1406        (a) When it is outputting text in the compiled version of a pattern, bytes
1407            other than 32-126 are always shown as hex escapes.
1409        (b) When it is outputting text that is a matched part of a subject string,
1410            it does the same, unless a different locale has been set for the match
1411            (using the /L modifier). In this case, it uses isprint() to decide.
1413     4. Fixed a major bug that caused incorrect computation of the amount of memory
1414        required for a compiled pattern when options that changed within the
1415        pattern affected the logic of the preliminary scan that determines the
1416        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1417        that the computed length was too small. The symptoms of this bug were
1418        either the PCRE error "internal error: code overflow" from pcre_compile(),
1419        or a glibc crash with a message such as "pcretest: free(): invalid next
1420        size (fast)". Examples of patterns that provoked this bug (shown in
1421        pcretest format) are:
1423          /(?-x: )/x
1424          /(?x)(?-x: \s*#\s*)/
1425          /((?i)[\x{c0}])/8
1426          /(?i:[\x{c0}])/8
1428        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1429        is now done differently.
1431     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1432        wrapper classes; (b) implement a new function in the C++ scanner that is
1433        more efficient than the old way of doing things because it avoids levels of
1434        recursion in the regex matching; (c) add a paragraph to the documentation
1435        for the FullMatch() function.
1437     6. The escape sequence \n was being treated as whatever was defined as
1438        "newline". Not only was this contrary to the documentation, which states
1439        that \n is character 10 (hex 0A), but it also went horribly wrong when
1440        "newline" was defined as CRLF. This has been fixed.
1442     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1443        was being set to -1 for the "end of line" case (supposedly a value that no
1444        character can have). Though this value is never used (the check for end of
1445        line is "zero bytes in current character"), it caused compiler complaints.
1446        I've changed it to 0xffffffff.
1448     8. In pcre_version.c, the version string was being built by a sequence of
1449        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1450        string (as it is for production releases) called a macro with an empty
1451        argument. The C standard says the result of this is undefined. The gcc
1452        compiler treats it as an empty string (which was what was wanted) but it is
1453        reported that Visual C gives an error. The source has been hacked around to
1454        avoid this problem.
1456     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1457        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1458        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1459        of them did).
1461    10. Originally, pcretest opened its input and output without "b"; then I was
1462        told that "b" was needed in some environments, so it was added for release
1463        5.0 to both the input and output. (It makes no difference on Unix-like
1464        systems.) Later I was told that it is wrong for the input on Windows. I've
1465        now abstracted the modes into two macros, to make it easier to fiddle with
1466        them, and removed "b" from the input mode under Windows.
1468    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1470    12. Added -help and --help to pcretest as an official way of being reminded
1471        of the options.
1473    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1474        and pcrecpp.cc because they annoy compilers at high warning levels.
1476    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1478    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1479        scripts are not C programs :-) and which was not noticed because it works
1480        on Linux.
1482    16. pcretest is supposed to handle any length of pattern and data line (as one
1483        line or as a continued sequence of lines) by extending its input buffer if
1484        necessary. This feature was broken for very long pattern lines, leading to
1485        a string of junk being passed to pcre_compile() if the pattern was longer
1486        than about 50K.
1488    17. I have done a major re-factoring of the way pcre_compile() computes the
1489        amount of memory needed for a compiled pattern. Previously, there was code
1490        that made a preliminary scan of the pattern in order to do this. That was
1491        OK when PCRE was new, but as the facilities have expanded, it has become
1492        harder and harder to keep it in step with the real compile phase, and there
1493        have been a number of bugs (see for example, 4 above). I have now found a
1494        cunning way of running the real compile function in a "fake" mode that
1495        enables it to compute how much memory it would need, while actually only
1496        ever using a few hundred bytes of working memory and without too many
1497        tests of the mode. This should make future maintenance and development
1498        easier. A side effect of this work is that the limit of 200 on the nesting
1499        depth of parentheses has been removed (though this was never a serious
1500        limitation, I suspect). However, there is a downside: pcre_compile() now
1501        runs more slowly than before (30% or more, depending on the pattern). I
1502        hope this isn't a big issue. There is no effect on runtime performance.
1504    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1505        newline (only possible for the last line of a file) and it was a
1506        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1508    19. Added additional timing features to pcretest. (1) The -tm option now times
1509        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1510        separate command line item, by a number that specifies the number of
1511        repeats to use when timing. The default is 50000; this gives better
1512        precision, but takes uncomfortably long for very large patterns.
1514    20. Extended pcre_study() to be more clever in cases where a branch of a
1515        subpattern has no definite first character. For example, (a*|b*)[cd] would
1516        previously give no result from pcre_study(). Now it recognizes that the
1517        first character must be a, b, c, or d.
1519    21. There was an incorrect error "recursive call could loop indefinitely" if
1520        a subpattern (or the entire pattern) that was being tested for matching an
1521        empty string contained only one non-empty item after a nested subpattern.
1522        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1523        incorrectly, because the \d was being skipped in the check.
1525    22. The pcretest program now has a new pattern option /B and a command line
1526        option -b, which is equivalent to adding /B to every pattern. This causes
1527        it to show the compiled bytecode, without the additional information that
1528        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1529        is the same as /B/I).
1531    23. A new optimization is now able automatically to treat some sequences such
1532        as a*b as a*+b. More specifically, if something simple (such as a character
1533        or a simple class like \d) has an unlimited quantifier, and is followed by
1534        something that cannot possibly match the quantified thing, the quantifier
1535        is automatically "possessified".
1537    24. A recursive reference to a subpattern whose number was greater than 39
1538        went wrong under certain circumstances in UTF-8 mode. This bug could also
1539        have affected the operation of pcre_study().
1541    25. Realized that a little bit of performance could be had by replacing
1542        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1544    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1546    27. Possessive quantifiers such as a++ were previously implemented by turning
1547        them into atomic groups such as ($>a+). Now they have their own opcodes,
1548        which improves performance. This includes the automatically created ones
1549        from 23 above.
1551    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1552        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1553        the first matched character to be a colon. This applied both to named and
1554        numbered groups.
1556    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1558    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1559        building PCRE on Windows easier, so I have included it in the distribution.
1561    31. There is now a check in pcretest against a ridiculously large number being
1562        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1563        loop, the loop is abandoned.
1565    32. Forward references to subpatterns in conditions such as (?(2)...) where
1566        subpattern 2 is defined later cause pcre_compile() to search forwards in
1567        the pattern for the relevant set of parentheses. This search went wrong
1568        when there were unescaped parentheses in a character class, parentheses
1569        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1571    33. "Subroutine" calls and backreferences were previously restricted to
1572        referencing subpatterns earlier in the regex. This restriction has now
1573        been removed.
1575    34. Added a number of extra features that are going to be in Perl 5.10. On the
1576        whole, these are just syntactic alternatives for features that PCRE had
1577        previously implemented using the Python syntax or my own invention. The
1578        other formats are all retained for compatibility.
1580        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1581            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1582            also .NET compatible.
1584        (b) A recursion or subroutine call to a named group can now be defined as
1585            (?&name) as well as (?P>name).
1587        (c) A backreference to a named group can now be defined as \k<name> or
1588            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1589            5.10, are also .NET compatible.
1591        (d) A conditional reference to a named group can now use the syntax
1592            (?(<name>) or (?('name') as well as (?(name).
1594        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1595            groups (named and numbered) that are never evaluated inline, but can be
1596            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1597            is always false. There may be only one alternative in such a group.
1599        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1600            as the simple (?(R). The condition is true only if the most recent
1601            recursion is that of the given number or name. It does not search out
1602            through the entire recursion stack.
1604        (g) The escape \gN or \g{N} has been added, where N is a positive or
1605            negative number, specifying an absolute or relative reference.
1607    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1608        some "unreachable code" warnings.
1610    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1611        things, this adds five new scripts.
1613    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1614        There were also incompatibilities regarding the handling of \Q..\E inside
1615        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1616        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1618    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1619        matches an empty string, and forcibly breaks the loop. There were bugs in
1620        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1621        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1622        separate and independent bugs (that affected different cases) have been
1623        fixed.
1625    39. Refactored the code to abolish the use of different opcodes for small
1626        capturing bracket numbers. This is a tidy that I avoided doing when I
1627        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1628        The new approach is not only tidier, it makes it possible to reduce the
1629        memory needed to fix the previous bug (38).
1631    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1632        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1633        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1634        mode.
1636    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1637        report.
1639    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1640        copy construction and assignment in the C++ wrapper.
1642    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1643        couple of bugs that could have given wrong results in the "--newline=crlf"
1644        case.
1646    44. Added a number of casts and did some reorganization of signed/unsigned int
1647        variables following suggestions from Dair Grant. Also renamed the variable
1648        "this" as "item" because it is a C++ keyword.
1650    45. Arranged for dftables to add
1652          #include "pcre_internal.h"
1654        to pcre_chartables.c because without it, gcc 4.x may remove the array
1655        definition from the final binary if PCRE is built into a static library and
1656        dead code stripping is activated.
1658    46. For an unanchored pattern, if a match attempt fails at the start of a
1659        newline sequence, and the newline setting is CRLF or ANY, and the next two
1660        characters are CRLF, advance by two characters instead of one.
1663    Version 6.7 04-Jul-06
1664    ---------------------
1666     1. In order to handle tests when input lines are enormously long, pcretest has
1667        been re-factored so that it automatically extends its buffers when
1668        necessary. The code is crude, but this _is_ just a test program. The
1669        default size has been increased from 32K to 50K.
1671     2. The code in pcre_study() was using the value of the re argument before
1672        testing it for NULL. (Of course, in any sensible call of the function, it
1673        won't be NULL.)
1675     3. The memmove() emulation function in pcre_internal.h, which is used on
1676        systems that lack both memmove() and bcopy() - that is, hardly ever -
1677        was missing a "static" storage class specifier.
1679     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1680        containing an extended class (one that cannot be represented by a bitmap
1681        because it contains high-valued characters or Unicode property items, e.g.
1682        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1683        pattern, but PCRE should not loop if you do not (it no longer does).
1684        [Detail: two cases were found: (a) a repeated subpattern containing an
1685        extended class; (b) a recursive reference to a subpattern that followed a
1686        previous extended class. It wasn't skipping over the extended class
1687        correctly when UTF-8 mode was not set.]
1689     5. A negated single-character class was not being recognized as fixed-length
1690        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1691        compile error "lookbehind assertion is not fixed length".
1693     6. The RunPerlTest auxiliary script was showing an unexpected difference
1694        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1695        write a Perl script that can interpret lines of an input file either as
1696        byte characters or as UTF-8, which is what "perltest" was being required to
1697        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1698        can't do is switch easily at run time between having the "use utf8;" pragma
1699        or not. In the end, I fudged it by using the RunPerlTest script to insert
1700        "use utf8;" explicitly for the UTF-8 tests.
1702     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1703        the end of the subject string, contrary to the documentation and to what
1704        Perl does. This was true of both matching functions. Now it matches only at
1705        the start of the subject and immediately after *internal* newlines.
1707     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1708        a pointer to an int instead of a pointer to an unsigned long int. This
1709        caused problems on 64-bit systems.
1711     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1712        instance of the 'standard' template library not being so standard".
1714    10. There was no check on the number of named subpatterns nor the maximum
1715        length of a subpattern name. The product of these values is used to compute
1716        the size of the memory block for a compiled pattern. By supplying a very
1717        long subpattern name and a large number of named subpatterns, the size
1718        computation could be caused to overflow. This is now prevented by limiting
1719        the length of names to 32 characters, and the number of named subpatterns
1720        to 10,000.
1722    11. Subpatterns that are repeated with specific counts have to be replicated in
1723        the compiled pattern. The size of memory for this was computed from the
1724        length of the subpattern and the repeat count. The latter is limited to
1725        65535, but there was no limit on the former, meaning that integer overflow
1726        could in principle occur. The compiled length of a repeated subpattern is
1727        now limited to 30,000 bytes in order to prevent this.
1729    12. Added the optional facility to have named substrings with the same name.
1731    13. Added the ability to use a named substring as a condition, using the
1732        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1733        are numbers (not recommended). Forward references are permitted.
1735    14. Added forward references in named backreferences (if you see what I mean).
1737    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1738        pattern could run off the end of the subject. For example, the pattern
1739        "(?s)(.{1,5})"8 did this with the subject "ab".
1741    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1742        PCRE_CASELESS was set when matching characters that were quantified with ?
1743        or *.
1745    17. A character class other than a single negated character that had a minimum
1746        but no maximum quantifier - for example [ab]{6,} - was not handled
1747        correctly by pce_dfa_exec(). It would match only one character.
1749    18. A valid (though odd) pattern that looked like a POSIX character
1750        class but used an invalid character after [ (for example [[,abc,]]) caused
1751        pcre_compile() to give the error "Failed: internal error: code overflow" or
1752        in some cases to crash with a glibc free() error. This could even happen if
1753        the pattern terminated after [[ but there just happened to be a sequence of
1754        letters, a binary zero, and a closing ] in the memory that followed.
1756    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1757        over the years. Originally (before any Unicode support), just the bottom 8
1758        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1759        output from "man perlunicode" includes this:
1761          The regular expression compiler produces polymorphic opcodes.  That
1762          is, the pattern adapts to the data and automatically switches to
1763          the Unicode character scheme when presented with Unicode data--or
1764          instead uses a traditional byte scheme when presented with byte
1765          data.
1767        Sadly, a wide octal escape does not cause a switch, and in a string with
1768        no other multibyte characters, these octal escapes are treated as before.
1769        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1770        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1771        Unicode string.
1773        I have not perpetrated such confusion in PCRE. Up till now, it took just
1774        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1775        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1776        translate to the appropriate multibyte character.
1778    29. Applied some refactoring to reduce the number of warnings from Microsoft
1779        and Borland compilers. This has included removing the fudge introduced
1780        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1781        a warning about an unused variable.
1783    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1784        characters since release 4.0, because Perl (from release 5.004) does not.
1785        [Or at least, is documented not to: some releases seem to be in conflict
1786        with the documentation.] However, when a pattern was studied with
1787        pcre_study() and all its branches started with \s, PCRE still included VT
1788        as a possible starting character. Of course, this did no harm; it just
1789        caused an unnecessary match attempt.
1791    22. Removed a now-redundant internal flag bit that recorded the fact that case
1792        dependency changed within the pattern. This was once needed for "required
1793        byte" processing, but is no longer used. This recovers a now-scarce options
1794        bit. Also moved the least significant internal flag bit to the most-
1795        significant bit of the word, which was not previously used (hangover from
1796        the days when it was an int rather than a uint) to free up another bit for
1797        the future.
1799    23. Added support for CRLF line endings as well as CR and LF. As well as the
1800        default being selectable at build time, it can now be changed at runtime
1801        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1802        specify that it is scanning data with non-default line endings.
1804    24. Changed the definition of CXXLINK to make it agree with the definition of
1805        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1807    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1808        recursions. This makes a big different to stack usage for some patterns.
1810    26. If a subpattern containing a named recursion or subroutine reference such
1811        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1812        the space required for the compiled pattern went wrong and gave too small a
1813        value. Depending on the environment, this could lead to "Failed: internal
1814        error: code overflow at offset 49" or "glibc detected double free or
1815        corruption" errors.
1817    27. Applied patches from Google (a) to support the new newline modes and (b) to
1818        advance over multibyte UTF-8 characters in GlobalReplace.
1820    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1821        difference for some implementation of PCRE in some Windows version.
1823    29. Added some extra testing facilities to pcretest:
1825        \q<number>   in a data line sets the "match limit" value
1826        \Q<number>   in a data line sets the "match recursion limt" value
1827        -S <number>  sets the stack size, where <number> is in megabytes
1829        The -S option isn't available for Windows.
1832    Version 6.6 06-Feb-06
1833    ---------------------
1835     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1836        in pcreposix.h. I have copied the definition from pcre.h.
1838     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1839        because pcre.h is no longer a built file.
1841     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1842        not normally included in the compiled code.
1845    Version 6.5 01-Feb-06
1846    ---------------------
1848     1. When using the partial match feature with pcre_dfa_exec(), it was not
1849        anchoring the second and subsequent partial matches at the new starting
1850        point. This could lead to incorrect results. For example, with the pattern
1851        /1234/, partially matching against "123" and then "a4" gave a match.
1853     2. Changes to pcregrep:
1855        (a) All non-match returns from pcre_exec() were being treated as failures
1856            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1857            error message is output. Some extra information is given for the
1858            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1859            probably the only errors that are likely to be caused by users (by
1860            specifying a regex that has nested indefinite repeats, for instance).
1861            If there are more than 20 of these errors, pcregrep is abandoned.
1863        (b) A binary zero was treated as data while matching, but terminated the
1864            output line if it was written out. This has been fixed: binary zeroes
1865            are now no different to any other data bytes.
1867        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1868            used to set a locale for matching. The --locale=xxxx long option has
1869            been added (no short equivalent) to specify a locale explicitly on the
1870            pcregrep command, overriding the environment variables.
1872        (d) When -B was used with -n, some line numbers in the output were one less
1873            than they should have been.
1875        (e) Added the -o (--only-matching) option.
1877        (f) If -A or -C was used with -c (count only), some lines of context were
1878            accidentally printed for the final match.
1880        (g) Added the -H (--with-filename) option.
1882        (h) The combination of options -rh failed to suppress file names for files
1883            that were found from directory arguments.
1885        (i) Added the -D (--devices) and -d (--directories) options.
1887        (j) Added the -F (--fixed-strings) option.
1889        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1891        (l) Added the --colo(u)r option.
1893        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1894            is not present by default.
1896     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1897        items such as (?R) or (?1), when the recursion could match a number of
1898        alternatives. If it matched one of the alternatives, but subsequently,
1899        outside the recursion, there was a failure, the code tried to back up into
1900        the recursion. However, because of the way PCRE is implemented, this is not
1901        possible, and the result was an incorrect result from the match.
1903        In order to prevent this happening, the specification of recursion has
1904        been changed so that all such subpatterns are automatically treated as
1905        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1907     4. I had overlooked the fact that, in some locales, there are characters for
1908        which isalpha() is true but neither isupper() nor islower() are true. In
1909        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1910        and ordfeminine) are like this. This affected the treatment of \w and \W
1911        when they appeared in character classes, but not when they appeared outside
1912        a character class. The bit map for "word" characters is now created
1913        separately from the results of isalnum() instead of just taking it from the
1914        upper, lower, and digit maps. (Plus the underscore character, of course.)
1916     5. The above bug also affected the handling of POSIX character classes such as
1917        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1918        permanent tables. Instead, the bit maps for such a class were previously
1919        created as the appropriate unions of the upper, lower, and digit bitmaps.
1920        Now they are created by subtraction from the [[:word:]] class, which has
1921        its own bitmap.
1923     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1924        It is created by subtracting the vertical space characters (\x09, \x0a,
1925        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1926        subtraction was done in the overall bitmap for a character class, meaning
1927        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1928        be recognized. This bug has been fixed.
1930     7. Patches from the folks at Google:
1932          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1933          real life, but is still worth protecting against".
1935          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1936          regular expressions".
1938          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1939          have it.
1941          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1942          "configure" and the latter not, in order to fix a problem somebody had
1943          with compiling the Arg class on HP-UX.
1945          (e) Improve the error-handling of the C++ wrapper a little bit.
1947          (f) New tests for checking recursion limiting.
1949     8. The pcre_memmove() function, which is used only if the environment does not
1950        have a standard memmove() function (and is therefore rarely compiled),
1951        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1952        returning a result (though PCRE never actually uses the result).
1954     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1955        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1956        returned instead of calling malloc() with an overflowing number that would
1957        most likely cause subsequent chaos.
1959    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1961    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1962        with this option is matched, the nmatch and pmatch options of regexec() are
1963        ignored.
1965    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1966        provided in case anyone wants to the the POSIX interface with UTF-8
1967        strings.
1969    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1970        C++ linking (needed for some HP-UX environments).
1972    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1973        (unused parameter) and in the pcre_printint() function (omitted "default"
1974        switch label when the default is to do nothing).
1976    15. Added some code to make it possible, when PCRE is compiled as a C++
1977        library, to replace subject pointers for pcre_exec() with a smart pointer
1978        class, thus making it possible to process discontinuous strings.
1980    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1981        much the same function. They were added by different people who were trying
1982        to make PCRE easy to compile on non-Unix systems. It has been suggested
1983        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1984        for compiling on Windows systems. I have therefore replaced it with
1985        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1986        defaults to "extern" for C or "extern C" for C++, which works fine on
1987        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1988        SCOPE with something explicit in config.h. In addition:
1990        (a) pcreposix.h still had just "extern" instead of either of these macros;
1991            I have replaced it with PCRE_DATA_SCOPE.
1993        (b) Functions such as _pcre_xclass(), which are internal to the library,
1994            but external in the C sense, all had PCRE_EXPORT in their definitions.
1995            This is apparently wrong for the Windows case, so I have removed it.
1996            (It makes no difference on Unix-like systems.)
1998    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1999        of recursive calls to match(). This is different to MATCH_LIMIT because
2000        that limits the total number of calls to match(), not all of which increase
2001        the depth of recursion. Limiting the recursion depth limits the amount of
2002        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2003        when PCRE is compiled, and changed at run time. A patch from Google adds
2004        this functionality to the C++ interface.
2006    18. Changes to the handling of Unicode character properties:
2008        (a) Updated the table to Unicode 4.1.0.
2010        (b) Recognize characters that are not in the table as "Cn" (undefined).
2012        (c) I revised the way the table is implemented to a much improved format
2013            which includes recognition of ranges. It now supports the ranges that
2014            are defined in UnicodeData.txt, and it also amalgamates other
2015            characters into ranges. This has reduced the number of entries in the
2016            table from around 16,000 to around 3,000, thus reducing its size
2017            considerably. I realized I did not need to use a tree structure after
2018            all - a binary chop search is just as efficient. Having reduced the
2019            number of entries, I extended their size from 6 bytes to 8 bytes to
2020            allow for more data.
2022        (d) Added support for Unicode script names via properties such as \p{Han}.
2024    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2025        matching that character.
2027    20. When matching a repeated Unicode property with a minimum greater than zero,
2028        (for example \pL{2,}), PCRE could look past the end of the subject if it
2029        reached it while seeking the minimum number of characters. This could
2030        happen only if some of the characters were more than one byte long, because
2031        there is a check for at least the minimum number of bytes.
2033    21. Refactored the implementation of \p and \P so as to be more general, to
2034        allow for more different types of property in future. This has changed the
2035        compiled form incompatibly. Anybody with saved compiled patterns that use
2036        \p or \P will have to recompile them.
2038    22. Added "Any" and "L&" to the supported property types.
2040    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2041        but give a compile time error if the value is greater than 0xff.
2043    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2044        accidentally not being installed or uninstalled.
2046    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2047        made were to insert the current release number. This seemed silly, because
2048        it made things harder for people building PCRE on systems that don't run
2049        "configure". I have turned pcre.h into a distributed file, no longer built
2050        by "configure", with the version identification directly included. There is
2051        no longer a pcre.h.in file.
2053        However, this change necessitated a change to the pcre-config script as
2054        well. It is built from pcre-config.in, and one of the substitutions was the
2055        release number. I have updated configure.ac so that ./configure now finds
2056        the release number by grepping pcre.h.
2058    26. Added the ability to run the tests under valgrind.
2061    Version 6.4 05-Sep-05
2062    ---------------------
2064     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2065        "--" to be printed when multiple files were scanned, even when none of the
2066        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2067        consider it to be a bug, and have restored the previous behaviour.
2069     2. A couple of code tidies to get rid of compiler warnings.
2071     3. The pcretest program used to cheat by referring to symbols in the library
2072        whose names begin with _pcre_. These are internal symbols that are not
2073        really supposed to be visible externally, and in some environments it is
2074        possible to suppress them. The cheating is now confined to including
2075        certain files from the library's source, which is a bit cleaner.
2077     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2078        file's purpose clearer.
2080     5. Reorganized pcre_ucp_findchar().
2083    Version 6.3 15-Aug-05
2084    ---------------------
2086     1. The file libpcre.pc.in did not have general read permission in the tarball.
2088     2. There were some problems when building without C++ support:
2090        (a) If C++ support was not built, "make install" and "make test" still
2091            tried to test it.
2093        (b) There were problems when the value of CXX was explicitly set. Some
2094            changes have been made to try to fix these, and ...
2096        (c) --disable-cpp can now be used to explicitly disable C++ support.
2098        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2099            backslash in a target when C++ was disabled. This confuses some
2100            versions of "make", apparently. Using an intermediate variable solves
2101            this. (Same for CPP_LOBJ.)
2103     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2104        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2105        necessary on certain architectures.
2107     4. Added a setting of -export-symbols-regex to the link command to remove
2108        those symbols that are exported in the C sense, but actually are local
2109        within the library, and not documented. Their names all begin with
2110        "_pcre_". This is not a perfect job, because (a) we have to except some
2111        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2112        available (and never for static libraries). I have made a note to try to
2113        find a way round (a) in the future.
2116  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
2117  ---------------------  ---------------------

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