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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.10 03 May-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.
63    Version 8.02 19-Mar-2010
64    ------------------------
66    1.  The Unicode data tables have been updated to Unicode 5.2.0.
68    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
69        configured.
71    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
72        original author of that file, following a query about its status.
74    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
75        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
77    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
78        quantifier applied to a forward-referencing subroutine call, could compile
79        incorrect code or give the error "internal error: previously-checked
80        referenced subpattern not found".
82    6.  Both MS Visual Studio and Symbian OS have problems with initializing
83        variables to point to external functions. For these systems, therefore,
84        pcre_malloc etc. are now initialized to local functions that call the
85        relevant global functions.
87    7.  There were two entries missing in the vectors called coptable and poptable
88        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
89        I've fixed the data, and added a kludgy way of testing at compile time that
90        the lengths are correct (equal to the number of opcodes).
92    8.  Following on from 7, I added a similar kludge to check the length of the
93        eint vector in pcreposix.c.
95    9.  Error texts for pcre_compile() are held as one long string to avoid too
96        much relocation at load time. To find a text, the string is searched,
97        counting zeros. There was no check for running off the end of the string,
98        which could happen if a new error number was added without updating the
99        string.
101    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
103    11. \K was not working if it appeared in an atomic group or in a group that
104        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
105        \K is "not well defined" if used in an assertion. PCRE now accepts it if
106        the assertion is positive, but not if it is negative.
108    12. Change 11 fortuitously reduced the size of the stack frame used in the
109        "match()" function of pcre_exec.c by one pointer. Forthcoming
110        implementation of support for (*MARK) will need an extra pointer on the
111        stack; I have reserved it now, so that the stack frame size does not
112        decrease.
114    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
115        item in branch that calls a recursion is a subroutine call - as in the
116        second branch in the above example - was incorrectly given the compile-
117        time error "recursive call could loop indefinitely" because pcre_compile()
118        was not correctly checking the subroutine for matching a non-empty string.
120    14. The checks for overrunning compiling workspace could trigger after an
121        overrun had occurred. This is a "should never occur" error, but it can be
122        triggered by pathological patterns such as hundreds of nested parentheses.
123        The checks now trigger 100 bytes before the end of the workspace.
125    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
128    Version 8.01 19-Jan-2010
129    ------------------------
131    1.  If a pattern contained a conditional subpattern with only one branch (in
132        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
133        computed the wrong minimum data length (which is of course zero for such
134        subpatterns). This could cause incorrect "no match" results.
136    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
137        the pattern is reset in the first branch, pcre_compile() failed with
138        "internal error: code overflow at offset...". This happened only when
139        the reset was to the original external option setting. (An optimization
140        abstracts leading options settings into an external setting, which was the
141        cause of this.)
143    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
144        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
145        assertion pattern did not match (meaning that the assertion was true), it
146        was incorrectly treated as false if the SKIP had been reached during the
147        matching. This also applied to assertions used as conditions.
149    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
150        assertion subpattern, including such a pattern used as a condition,
151        unpredictable results occurred, instead of the error return
154    5.  The C++ GlobalReplace function was not working like Perl for the special
155        situation when an empty string is matched. It now does the fancy magic
156        stuff that is necessary.
158    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
159        removed. (These were left over from very, very early versions of PCRE.)
161    7.  Some cosmetic changes to the code to make life easier when compiling it
162        as part of something else:
164        (a) Change DEBUG to PCRE_DEBUG.
166        (b) In pcre_compile(), rename the member of the "branch_chain" structure
167            called "current" as "current_branch", to prevent a collision with the
168            Linux macro when compiled as a kernel module.
170        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
171            prevent a collision with the Linux macro when compiled as a kernel
172            module.
174    8.  In pcre_compile() there are some checks for integer overflows that used to
175        cast potentially large values to (double). This has been changed to that
176        when building, a check for int64_t is made, and if it is found, it is used
177        instead, thus avoiding the use of floating point arithmetic. (There is no
178        other use of FP in PCRE.) If int64_t is not found, the fallback is to
179        double.
181    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
182        2005 (difference between two addresses compared to an unsigned value).
184    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
185        custom one, because of the following reported problem in Windows:
187          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
188              under Win32.
189          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
190              therefore missing the function definition.
191          - The compiler thus generates a "C" signature for the test function.
192          - The linker fails to find the "C" function.
193          - PCRE fails to configure if asked to do so against libbz2.
195    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
196        messages were output:
198          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
199          rerunning libtoolize, to keep the correct libtool macros in-tree.
200          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
202        I have done both of these things.
204    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
205        most of the time, it *can* run out if it is given a pattern that contains a
206        runaway infinite recursion. I updated the discussion in the pcrestack man
207        page.
209    13. Now that we have gone to the x.xx style of version numbers, the minor
210        version may start with zero. Using 08 or 09 is a bad idea because users
211        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
212        interpreted as invalid octal numbers. I've updated the previous comment in
213        configure.ac, and also added a check that gives an error if 08 or 09 are
214        used.
216    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
217        causing partial matching to fail when the end of the subject matched \W
218        in a UTF-8 pattern where \W was quantified with a minimum of 3.
220    15. There were some discrepancies between the declarations in pcre_internal.h
221        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
222        their definitions. The declarations used "const uschar *" and the
223        definitions used USPTR. Even though USPTR is normally defined as "const
224        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
225        reported that: "This difference in casting confuses some C++ compilers, for
226        example, SunCC recognizes above declarations as different functions and
227        generates broken code for hbpcre." I have changed the declarations to use
228        USPTR.
230    16. GNU libtool is named differently on some systems. The autogen.sh script now
231        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
232        (FreeBSD).
234    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
235        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
236        comment: "Figure out how to create a longlong from a string: strtoll and
237        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
238        instance, but it only takes 2 args instead of 3!"
240    18. A subtle bug concerned with back references has been fixed by a change of
241        specification, with a corresponding code fix. A pattern such as
242        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
243        refers, was giving matches when it shouldn't. For example, xa=xaaa would
244        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
245        same bug. Such groups have to be quantified to be useful, or contained
246        inside another quantified group. (If there's no repetition, the reference
247        can never match.) The problem arises because, having left the group and
248        moved on to the rest of the pattern, a later failure that backtracks into
249        the group uses the captured value from the final iteration of the group
250        rather than the correct earlier one. I have fixed this in PCRE by forcing
251        any group that contains a reference to itself to be an atomic group; that
252        is, there cannot be any backtracking into it once it has completed. This is
253        similar to recursive and subroutine calls.
256    Version 8.00 19-Oct-09
257    ----------------------
259    1.  The table for translating pcre_compile() error codes into POSIX error codes
260        was out-of-date, and there was no check on the pcre_compile() error code
261        being within the table. This could lead to an OK return being given in
262        error.
264    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
265        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
266        in a Windows environment.
268    3.  The pcregrep --count option prints the count for each file even when it is
269        zero, as does GNU grep. However, pcregrep was also printing all files when
270        --files-with-matches was added. Now, when both options are given, it prints
271        counts only for those files that have at least one match. (GNU grep just
272        prints the file name in this circumstance, but including the count seems
273        more useful - otherwise, why use --count?) Also ensured that the
274        combination -clh just lists non-zero counts, with no names.
276    4.  The long form of the pcregrep -F option was incorrectly implemented as
277        --fixed_strings instead of --fixed-strings. This is an incompatible change,
278        but it seems right to fix it, and I didn't think it was worth preserving
279        the old behaviour.
281    5.  The command line items --regex=pattern and --regexp=pattern were not
282        recognized by pcregrep, which required --regex pattern or --regexp pattern
283        (with a space rather than an '='). The man page documented the '=' forms,
284        which are compatible with GNU grep; these now work.
286    6.  No libpcreposix.pc file was created for pkg-config; there was just
287        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
289    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
290        when UCP support is not needed, by modifying the Python script that
291        generates it from Unicode data files. This should not matter if the module
292        is correctly used as a library, but I received one complaint about 50K of
293        unwanted data. My guess is that the person linked everything into his
294        program rather than using a library. Anyway, it does no harm.
296    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
297        was a minimum greater than 1 for a wide character in a possessive
298        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
299        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
300        character. Chaos in the form of incorrect output or a compiling loop could
301        result.
303    9.  The restrictions on what a pattern can contain when partial matching is
304        requested for pcre_exec() have been removed. All patterns can now be
305        partially matched by this function. In addition, if there are at least two
306        slots in the offset vector, the offset of the earliest inspected character
307        for the match and the offset of the end of the subject are set in them when
308        PCRE_ERROR_PARTIAL is returned.
310    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
311        synonymous with PCRE_PARTIAL, for backwards compatibility, and
312        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
313        and may be more useful for multi-segment matching.
315    11. Partial matching with pcre_exec() is now more intuitive. A partial match
316        used to be given if ever the end of the subject was reached; now it is
317        given only if matching could not proceed because another character was
318        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
319        string "Z", which now yields "no match" instead of "partial match". In the
320        case of pcre_dfa_exec(), "no match" is given if every matching path for the
321        final character ended with (*FAIL).
323    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
324        if the pattern had a "must contain" character that was already found in the
325        earlier partial match, unless partial matching was again requested. For
326        example, with the pattern /dog.(body)?/, the "must contain" character is
327        "g". If the first part-match was for the string "dog", restarting with
328        "sbody" failed. This bug has been fixed.
330    13. The string returned by pcre_dfa_exec() after a partial match has been
331        changed so that it starts at the first inspected character rather than the
332        first character of the match. This makes a difference only if the pattern
333        starts with a lookbehind assertion or \b or \B (\K is not supported by
334        pcre_dfa_exec()). It's an incompatible change, but it makes the two
335        matching functions compatible, and I think it's the right thing to do.
337    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
338        so that the demonstration program is easily available in environments where
339        PCRE has not been installed from source.
341    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
342        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
343        library.
345    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
346        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
347        is not the first non-POSIX option to be added. Clearly some people find
348        these options useful.
350    17. If a caller to the POSIX matching function regexec() passes a non-zero
351        value for nmatch with a NULL value for pmatch, the value of
352        nmatch is forced to zero.
354    18. RunGrepTest did not have a test for the availability of the -u option of
355        the diff command, as RunTest does. It now checks in the same way as
356        RunTest, and also checks for the -b option.
358    19. If an odd number of negated classes containing just a single character
359        interposed, within parentheses, between a forward reference to a named
360        subpattern and the definition of the subpattern, compilation crashed with
361        an internal error, complaining that it could not find the referenced
362        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
363        [The bug was that it was starting one character too far in when skipping
364        over the character class, thus treating the ] as data rather than
365        terminating the class. This meant it could skip too much.]
367    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
368        /g option in pcretest when the pattern contains \K, which makes it possible
369        to have an empty string match not at the start, even when the pattern is
370        anchored. Updated pcretest and pcredemo to use this option.
372    21. If the maximum number of capturing subpatterns in a recursion was greater
373        than the maximum at the outer level, the higher number was returned, but
374        with unset values at the outer level. The correct (outer level) value is
375        now given.
377    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
378        PCRE did not set those parentheses (unlike Perl). I have now found a way to
379        make it do so. The string so far is captured, making this feature
380        compatible with Perl.
382    23. The tests have been re-organized, adding tests 11 and 12, to make it
383        possible to check the Perl 5.10 features against Perl 5.10.
385    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
386        pattern matches a fixed length string. PCRE did not allow this; now it
387        does. Neither allows recursion.
389    25. I finally figured out how to implement a request to provide the minimum
390        length of subject string that was needed in order to match a given pattern.
391        (It was back references and recursion that I had previously got hung up
392        on.) This code has now been added to pcre_study(); it finds a lower bound
393        to the length of subject needed. It is not necessarily the greatest lower
394        bound, but using it to avoid searching strings that are too short does give
395        some useful speed-ups. The value is available to calling programs via
396        pcre_fullinfo().
398    26. While implementing 25, I discovered to my embarrassment that pcretest had
399        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
400        study optimizations had never been tested with that matching function.
401        Oops. What is worse, even when it was passed study data, there was a bug in
402        pcre_dfa_exec() that meant it never actually used it. Double oops. There
403        were also very few tests of studied patterns with pcre_dfa_exec().
405    27. If (?| is used to create subpatterns with duplicate numbers, they are now
406        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
407        on the other side of the coin, they are no longer allowed to have different
408        names, because these cannot be distinguished in PCRE, and this has caused
409        confusion. (This is a difference from Perl.)
411    28. When duplicate subpattern names are present (necessarily with different
412        numbers, as required by 27 above), and a test is made by name in a
413        conditional pattern, either for a subpattern having been matched, or for
414        recursion in such a pattern, all the associated numbered subpatterns are
415        tested, and the overall condition is true if the condition is true for any
416        one of them. This is the way Perl works, and is also more like the way
417        testing by number works.
420    Version 7.9 11-Apr-09
421    ---------------------
423    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
424        (pcretest), all targets were linked against these libraries. This included
425        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
426        libraries. This caused unwanted dependencies to be created. This problem
427        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
428        pcretest is linked with readline.
430    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
431        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
432        moved outside it again, because FALSE and TRUE are already defined in AIX,
433        but BOOL is not.
435    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
436        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
438    4.  The pcregrep documentation said spaces were inserted as well as colons (or
439        hyphens) following file names and line numbers when outputting matching
440        lines. This is not true; no spaces are inserted. I have also clarified the
441        wording for the --colour (or --color) option.
443    5.  In pcregrep, when --colour was used with -o, the list of matching strings
444        was not coloured; this is different to GNU grep, so I have changed it to be
445        the same.
447    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
448        each matching line was coloured. Now it goes on to look for further matches
449        of any of the test patterns, which is the same behaviour as GNU grep.
451    7.  A pattern that could match an empty string could cause pcregrep to loop; it
452        doesn't make sense to accept an empty string match in pcregrep, so I have
453        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
454        seems to be how GNU grep behaves.
456    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
457        start or after a newline", because the conditional assertion was not being
458        correctly handled. The rule now is that both the assertion and what follows
459        in the first alternative must satisfy the test.
461    9.  If auto-callout was enabled in a pattern with a conditional group whose
462        condition was an assertion, PCRE could crash during matching, both with
463        pcre_exec() and pcre_dfa_exec().
465    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
466        used for matching.
468    11. Unicode property support in character classes was not working for
469        characters (bytes) greater than 127 when not in UTF-8 mode.
471    12. Added the -M command line option to pcretest.
473    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
475    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
477    16. Added comments and documentation about mis-use of no_arg in the C++
478        wrapper.
480    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
481        from Martin Jerabek that uses macro names for all relevant character and
482        string constants.
484    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
485        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
486        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
487        these, but not everybody uses configure.
489    19. A conditional group that had only one branch was not being correctly
490        recognized as an item that could match an empty string. This meant that an
491        enclosing group might also not be so recognized, causing infinite looping
492        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
493        with the subject "ab", where knowledge that the repeated group can match
494        nothing is needed in order to break the loop.
496    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
497        exec(), but without supplying a callout function, matching went wrong.
499    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
500        leak if the size of the offset vector was greater than 30. When the vector
501        is smaller, the saved offsets during recursion go onto a local stack
502        vector, but for larger vectors malloc() is used. It was failing to free
503        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
504        error, in fact).
506    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
507        heapframe that is used only when UTF-8 support is enabled. This caused no
508        problem, but was untidy.
510    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
511        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
512        included within another project.
514    24. Steven Van Ingelgem's patches to add more options to the CMake support,
515        slightly modified by me:
517          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
518              not building pcregrep.
520          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
521              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
523    25. Forward references, both numeric and by name, in patterns that made use of
524        duplicate group numbers, could behave incorrectly or give incorrect errors,
525        because when scanning forward to find the reference group, PCRE was not
526        taking into account the duplicate group numbers. A pattern such as
527        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
529    26. Changed a few more instances of "const unsigned char *" to USPTR, making
530        the feature of a custom pointer more persuasive (as requested by a user).
532    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
533        pcretest.c, inside #ifndefs, because it seems they are sometimes already
534        pre-defined.
536    28. Added support for (*UTF8) at the start of a pattern.
538    29. Arrange for flags added by the "release type" setting in CMake to be shown
539        in the configuration summary.
542    Version 7.8 05-Sep-08
543    ---------------------
545    1.  Replaced UCP searching code with optimized version as implemented for Ad
546        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
547        stage table and inline lookup instead of a function, giving speed ups of 2
548        to 5 times on some simple patterns that I tested. Permission was given to
549        distribute the MultiStage2.py script that generates the tables (it's not in
550        the tarball, but is in the Subversion repository).
552    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
553        scripts.
555    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
556        a group with a zero qualifier. The result of the study could be incorrect,
557        or the function might crash, depending on the pattern.
559    4.  Caseless matching was not working for non-ASCII characters in back
560        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
561        It now works when Unicode Property Support is available.
563    5.  In pcretest, an escape such as \x{de} in the data was always generating
564        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
565        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
566        truncation.
568    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
570    7.  Added two (int) casts to pcregrep when printing the difference of two
571        pointers, in case they are 64-bit values.
573    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
574        test 2 if it fails.
576    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
577        and a #define of that name to empty if it is not externally set. This is to
578        allow users of MSVC to set it if necessary.
580    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
581        the convenience functions in the pcre_get.c source file.
583    11. An option change at the start of a pattern that had top-level alternatives
584        could cause overwriting and/or a crash. This command provoked a crash in
585        some environments:
587          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
589        This potential security problem was recorded as CVE-2008-2371.
591    12. For a pattern where the match had to start at the beginning or immediately
592        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
593        pcre_dfa_exec() could read past the end of the passed subject if there was
594        no match. To help with detecting such bugs (e.g. with valgrind), I modified
595        pcretest so that it places the subject at the end of its malloc-ed buffer.
597    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
598        exec() might read past the end of the data buffer in UTF-8 mode.
600    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
601        the data contained the byte 0x85 as part of a UTF-8 character within its
602        first line. This applied both to normal and DFA matching.
604    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
605        /^[^d]*?$/8 failed to match "abc".
607    16. Added a missing copyright notice to pcrecpp_internal.h.
609    17. Make it more clear in the documentation that values returned from
610        pcre_exec() in ovector are byte offsets, not character counts.
612    18. Tidied a few places to stop certain compilers from issuing warnings.
614    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
615        supplied by Stefan Weber. I made a further small update for 7.8 because
616        there is a change of source arrangements: the pcre_searchfuncs.c module is
617        replaced by pcre_ucd.c.
620    Version 7.7 07-May-08
621    ---------------------
623    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
624        a string to a long long, pretend we don't even have a long long." This is
625        done by checking for the strtoq, strtoll, and _strtoi64 functions.
627    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
628        pre-7.6 versions, which defined a global no_arg variable instead of putting
629        it in the RE class. (See also #8 below.)
631    3.  Remove a line of dead code, identified by coverity and reported by Nuno
632        Lopes.
634    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
636        (1) The include/exclude patterns were being applied to the whole pathnames
637            of files, instead of just to the final components.
639        (2) If there was more than one level of directory, the subdirectories were
640            skipped unless they satisfied the include/exclude conditions. This is
641            inconsistent with GNU grep (and could even be seen as contrary to the
642            pcregrep specification - which I improved to make it absolutely clear).
643            The action now is always to scan all levels of directory, and just
644            apply the include/exclude patterns to regular files.
646    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
647        --exclude_dir in the tests to avoid scanning .svn directories.
649    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
650        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
651        doesn't support NULs in patterns.
653    7.  Added some missing "const"s to declarations of static tables in
654        pcre_compile.c and pcre_dfa_exec.c.
656    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
657        caused by fix #2  above. (Subsequently also a second patch to fix the
658        first patch. And a third patch - this was a messy problem.)
660    9.  Applied Craig's patch to remove the use of push_back().
662    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
663        matching function regexec().
665    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
666        which, however, unlike Perl's \g{...}, are subroutine calls, not back
667        references. PCRE supports relative numbers with this syntax (I don't think
668        Oniguruma does).
670    12. Previously, a group with a zero repeat such as (...){0} was completely
671        omitted from the compiled regex. However, this means that if the group
672        was called as a subroutine from elsewhere in the pattern, things went wrong
673        (an internal error was given). Such groups are now left in the compiled
674        pattern, with a new opcode that causes them to be skipped at execution
675        time.
677    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
678        to the way PCRE behaves:
680        (a) A lone ] character is dis-allowed (Perl treats it as data).
682        (b) A back reference to an unmatched subpattern matches an empty string
683            (Perl fails the current match path).
685        (c) A data ] in a character class must be notated as \] because if the
686            first data character in a class is ], it defines an empty class. (In
687            Perl it is not possible to have an empty class.) The empty class []
688            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
689            The negative empty class [^] matches any one character, independently
690            of the DOTALL setting.
692    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
693        non-existent subpattern following a character class starting with ']' and
694        containing () gave an internal compiling error instead of "reference to
695        non-existent subpattern". Fortunately, when the pattern did exist, the
696        compiled code was correct. (When scanning forwards to check for the
697        existencd of the subpattern, it was treating the data ']' as terminating
698        the class, so got the count wrong. When actually compiling, the reference
699        was subsequently set up correctly.)
701    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
702        it was being rejected as not supported by pcre_dfa_exec(), even though
703        other assertions are supported. I have made pcre_dfa_exec() support
704        (*FAIL).
706    16. The implementation of 13c above involved the invention of a new opcode,
707        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
708        cannot be changed at match time, I realized I could make a small
709        improvement to matching performance by compiling OP_ALLANY instead of
710        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
711        on the OP_ANY path.
713    17. Compiling pcretest on Windows with readline support failed without the
714        following two fixes: (1) Make the unistd.h include conditional on
715        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
717    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
718        ncurses library to be included for pcretest when ReadLine support is
719        requested, but also to allow for it to be overridden. This patch came from
720        Daniel Bergström.
722    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
723        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
724        any errors with the current Unicode tables. Thanks to Peter Kankowski for
725        spotting this.
728    Version 7.6 28-Jan-08
729    ---------------------
731    1.  A character class containing a very large number of characters with
732        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
733        overflow.
735    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
736        HAVE_LONG_LONG is not defined.
738    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
739        bring them up to date and include new features. This patch includes:
741        - Fixed PH's badly added libz and libbz2 support.
742        - Fixed a problem with static linking.
743        - Added pcredemo. [But later removed - see 7 below.]
744        - Fixed dftables problem and added an option.
745        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
746            HAVE_LONG_LONG.
747        - Added readline support for pcretest.
748        - Added an listing of the option settings after cmake has run.
750    4.  A user submitted a patch to Makefile that makes it easy to create
751        "pcre.dll" under mingw when using Configure/Make. I added stuff to
752        Makefile.am that cause it to include this special target, without
753        affecting anything else. Note that the same mingw target plus all
754        the other distribution libraries and programs are now supported
755        when configuring with CMake (see 6 below) instead of with
756        Configure/Make.
758    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
759        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
760        exported in the Windows port". It has not yet been confirmed that the patch
761        solves the problem, but it does no harm.
763    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
764        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
765        with CMake, and also correct the comment about stack recursion.
767    7.  Remove the automatic building of pcredemo from the ./configure system and
768        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
769        of a program that users should build themselves after PCRE is installed, so
770        building it automatically is not really right. What is more, it gave
771        trouble in some build environments.
773    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
776    Version 7.5 10-Jan-08
777    ---------------------
779    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
780        values in parens when parsing an RE using the C++ wrapper."
782    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
783        Characters greater than 255 were excluded from the class instead of being
784        included.
786    3.  The same bug as (2) above applied to negated POSIX classes such as
787        [:^space:].
789    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
790        defined or documented. It seems to have been a typo for PCRE_STATIC, so
791        I have changed it.
793    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
794        first named subpattern) and a construct such as (?&a) would reference the
795        first named subpattern whose name started with "a" (in other words, the
796        length check was missing). Both these problems are fixed. "Subpattern name
797        expected" is now given for (?&) (a zero-length name), and this patch also
798        makes it give the same error for \k'' (previously it complained that that
799        was a reference to a non-existent subpattern).
801    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
802        this is right because (?- can be followed by option settings as well as by
803        digits. I have, however, made the messages clearer.
805    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
806        than the number used in the conditional) now cause a compile-time error.
807        This is actually not compatible with Perl, which accepts such patterns, but
808        treats the conditional as always being FALSE (as PCRE used to), but it
809        seems to me that giving a diagnostic is better.
811    8.  Change "alphameric" to the more common word "alphanumeric" in comments
812        and messages.
814    9.  Fix two occurrences of "backslash" in comments that should have been
815        "backspace".
817    10. Remove two redundant lines of code that can never be obeyed (their function
818        was moved elsewhere).
820    11. The program that makes PCRE's Unicode character property table had a bug
821        which caused it to generate incorrect table entries for sequences of
822        characters that have the same character type, but are in different scripts.
823        It amalgamated them into a single range, with the script of the first of
824        them. In other words, some characters were in the wrong script. There were
825        thirteen such cases, affecting characters in the following ranges:
827          U+002b0 - U+002c1
828          U+0060c - U+0060d
829          U+0061e - U+00612
830          U+0064b - U+0065e
831          U+0074d - U+0076d
832          U+01800 - U+01805
833          U+01d00 - U+01d77
834          U+01d9b - U+01dbf
835          U+0200b - U+0200f
836          U+030fc - U+030fe
837          U+03260 - U+0327f
838          U+0fb46 - U+0fbb1
839          U+10450 - U+1049d
841    12. The -o option (show only the matching part of a line) for pcregrep was not
842        compatible with GNU grep in that, if there was more than one match in a
843        line, it showed only the first of them. It now behaves in the same way as
844        GNU grep.
846    13. If the -o and -v options were combined for pcregrep, it printed a blank
847        line for every non-matching line. GNU grep prints nothing, and pcregrep now
848        does the same. The return code can be used to tell if there were any
849        non-matching lines.
851    14. Added --file-offsets and --line-offsets to pcregrep.
853    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
854        infinitely looping recursion. The bug was that positive lookaheads were not
855        being skipped when checking for a possible empty match (negative lookaheads
856        and both kinds of lookbehind were skipped).
858    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
859        inclusion of <windows.h> to before rather than after the definition of
860        INVALID_FILE_ATTRIBUTES (patch from David Byron).
862    17. Specifying a possessive quantifier with a specific limit for a Unicode
863        character property caused pcre_compile() to compile bad code, which led at
864        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
865        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
866        caused the error; without that there was no problem.
868    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
870    19. Added --enable-pcretest-libreadline.
872    20. In pcrecpp.cc, the variable 'count' was incremented twice in
873        RE::GlobalReplace(). As a result, the number of replacements returned was
874        double what it should be. I removed one of the increments, but Craig sent a
875        later patch that removed the other one (the right fix) and added unit tests
876        that check the return values (which was not done before).
878    21. Several CMake things:
880        (1) Arranged that, when cmake is used on Unix, the libraries end up with
881            the names libpcre and libpcreposix, not just pcre and pcreposix.
883        (2) The above change means that pcretest and pcregrep are now correctly
884            linked with the newly-built libraries, not previously installed ones.
888    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
889        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
890        UTF-8 newline character). The key issue is that the pattern starts .*;
891        this means that the match must be either at the beginning, or after a
892        newline. The bug was in the code for advancing after a failed match and
893        checking that the new position followed a newline. It was not taking
894        account of UTF-8 characters correctly.
896    23. PCRE was behaving differently from Perl in the way it recognized POSIX
897        character classes. PCRE was not treating the sequence [:...:] as a
898        character class unless the ... were all letters. Perl, however, seems to
899        allow any characters between [: and :], though of course it rejects as
900        unknown any "names" that contain non-letters, because all the known class
901        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
902        for example, whereas PCRE did not - it did not recognize a POSIX character
903        class. This seemed a bit dangerous, so the code has been changed to be
904        closer to Perl. The behaviour is not identical to Perl, because PCRE will
905        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
906        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
907        Perl does, and where it didn't before.
909    24. Rewrite so as to remove the single use of %n from pcregrep because in some
910        Windows environments %n is disabled by default.
913    Version 7.4 21-Sep-07
914    ---------------------
916    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
917        means that a class such as [\s] counted as "explicit reference to CR or
918        LF". That isn't really right - the whole point of the change was to try to
919        help when there was an actual mention of one of the two characters. So now
920        the change happens only if \r or \n (or a literal CR or LF) character is
921        encountered.
923    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
924        of both had grown to the point where there were only 3 bits left.
925        Fortunately, there was spare space in the data structure, and so I have
926        moved the internal flags into a new 16-bit field to free up more option
927        bits.
929    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
930        but did not set the internal JCHANGED flag - either of these is enough to
931        control the way the "get" function works - but the PCRE_INFO_JCHANGED
932        facility is supposed to tell if (?J) was ever used, so now (?J) at the
933        start sets both bits.
935    4.  Added options (at build time, compile time, exec time) to change \R from
936        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
938    5.  doc/pcresyntax.html was missing from the distribution.
940    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
941        compatibility, even though it is no longer used.
943    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
944        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
945        windows.h file is present (where different names are used). [This was
946        reversed later after testing - see 16 below.]
948    8.  Changed all #include <config.h> to #include "config.h". There were also
949        some further <pcre.h> cases that I changed to "pcre.h".
951    9.  When pcregrep was used with the --colour option, it missed the line ending
952        sequence off the lines that it output.
954    10. It was pointed out to me that arrays of string pointers cause lots of
955        relocations when a shared library is dynamically loaded. A technique of
956        using a single long string with a table of offsets can drastically reduce
957        these. I have refactored PCRE in four places to do this. The result is
958        dramatic:
960          Originally:                          290
961          After changing UCP table:            187
962          After changing error message table:   43
963          After changing table of "verbs"       36
964          After changing table of Posix names   22
966        Thanks to the folks working on Gregex for glib for this insight.
968    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
969        unicode-properties was also set.
971    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
973    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
974        checked only for CRLF.
976    14. Added casts to pcretest.c to avoid compiler warnings.
978    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
980    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
981        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
982        entirely. This removes changes made in 7 above.
984    17. The CMake files have been updated, and there is now more information about
985        building with CMake in the NON-UNIX-USE document.
988    Version 7.3 28-Aug-07
989    ---------------------
991     1. In the rejigging of the build system that eventually resulted in 7.1, the
992        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
993        brackets there is not right, since it causes compilers to look for an
994        installed pcre.h, not the version that is in the source that is being
995        compiled (which of course may be different). I have changed it back to:
997          #include "pcre.h"
999        I have a vague recollection that the change was concerned with compiling in
1000        different directories, but in the new build system, that is taken care of
1001        by the VPATH setting the Makefile.
1003     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1004        when the subject happened to end in the byte 0x85 (e.g. if the last
1005        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1006        characters but of course it shouldn't be taken as a newline when it is part
1007        of another character. The bug was that, for an unlimited repeat of . in
1008        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1009        characters when looking for a newline.
1011     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1013     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1014        in debug output.
1016     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1017        long printing in the pcrecpp unittest when running under MinGW.
1019     6. ESC_K was left out of the EBCDIC table.
1021     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1022        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1023        limit also applies to "virtual nesting" when a pattern is recursive, and in
1024        this case 1000 isn't so big. I have been able to remove this limit at the
1025        expense of backing off one optimization in certain circumstances. Normally,
1026        when pcre_exec() would call its internal match() function recursively and
1027        immediately return the result unconditionally, it uses a "tail recursion"
1028        feature to save stack. However, when a subpattern that can match an empty
1029        string has an unlimited repetition quantifier, it no longer makes this
1030        optimization. That gives it a stack frame in which to save the data for
1031        checking that an empty string has been matched. Previously this was taken
1032        from the 1000-entry workspace that had been reserved. So now there is no
1033        explicit limit, but more stack is used.
1035     8. Applied Daniel's patches to solve problems with the import/export magic
1036        syntax that is required for Windows, and which was going wrong for the
1037        pcreposix and pcrecpp parts of the library. These were overlooked when this
1038        problem was solved for the main library.
1040     9. There were some crude static tests to avoid integer overflow when computing
1041        the size of patterns that contain repeated groups with explicit upper
1042        limits. As the maximum quantifier is 65535, the maximum group length was
1043        set at 30,000 so that the product of these two numbers did not overflow a
1044        32-bit integer. However, it turns out that people want to use groups that
1045        are longer than 30,000 bytes (though not repeat them that many times).
1046        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1047        made it possible to implement the integer overflow checks in a much more
1048        dynamic way, which I have now done. The artificial limitation on group
1049        length has been removed - we now have only the limit on the total length of
1050        the compiled pattern, which depends on the LINK_SIZE setting.
1052    10. Fixed a bug in the documentation for get/copy named substring when
1053        duplicate names are permitted. If none of the named substrings are set, the
1054        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1055        empty string.
1057    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1058        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1059        because the ] is interpreted as the first data character and the
1060        terminating ] is not found. PCRE has been made compatible with Perl in this
1061        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1062        cause memory overwriting.
1064    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1065        string has been matched (to stop an infinite loop). It was not recognizing
1066        a conditional subpattern that could match an empty string if that
1067        subpattern was within another subpattern. For example, it looped when
1068        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1069        condition was not nested. This bug has been fixed.
1071    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1072        past the start of the subject in the presence of bytes with the top bit
1073        set, for example "\x8aBCD".
1075    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1076        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1078    14. Optimized (?!) to (*FAIL).
1080    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1081        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1082        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1083        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1084        does: it's just the validity check that is more restrictive.
1086    16. Inserted checks for integer overflows during escape sequence (backslash)
1087        processing, and also fixed erroneous offset values for syntax errors during
1088        backslash processing.
1090    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1091        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1093    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1094        caused an overrun.
1096    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1097        something other than just ASCII characters) inside a group that had an
1098        unlimited repeat caused a loop at compile time (while checking to see
1099        whether the group could match an empty string).
1101    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1102        [\P{Any}] did so. (Error in the code for printing property names.)
1104    21. An orphan \E inside a character class could cause a crash.
1106    22. A repeated capturing bracket such as (A)? could cause a wild memory
1107        reference during compilation.
1109    23. There are several functions in pcre_compile() that scan along a compiled
1110        expression for various reasons (e.g. to see if it's fixed length for look
1111        behind). There were bugs in these functions when a repeated \p or \P was
1112        present in the pattern. These operators have additional parameters compared
1113        with \d, etc, and these were not being taken into account when moving along
1114        the compiled data. Specifically:
1116        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1117            length.
1119        (b) An item such as \pL+ within a repeated group could cause crashes or
1120            loops.
1122        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1123            "reference to non-existent subpattern" error.
1125        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1127    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1128        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1130    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1132    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1133        character were causing crashes (broken optimization).
1135    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1136        \p or \P) caused a compile-time loop.
1138    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1139        break. For example, the unstudied pattern [\r\n]A does not match the string
1140        "\r\nA" because change 7.0/46 below moves the current point on by two
1141        characters after failing to match at the start. However, the pattern \nA
1142        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1143        the same is true. There doesn't seem any very clean way out of this, but
1144        what I have chosen to do makes the common cases work: PCRE now takes note
1145        of whether there can be an explicit match for \r or \n anywhere in the
1146        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1147        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1148        pattern has explicit CR or LF references.
1150    29. Added (*CR) etc for changing newline setting at start of pattern.
1153    Version 7.2 19-Jun-07
1154    ---------------------
1156     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1157        which is apparently normally available under Windows.
1159     2. Re-jig the pcregrep tests with different newline settings in an attempt
1160        to make them independent of the local environment's newline setting.
1162     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1164     4. Some of the "internals" tests were previously cut out when the link size
1165        was not 2, because the output contained actual offsets. The recent new
1166        "Z" feature of pcretest means that these can be cut out, making the tests
1167        usable with all link sizes.
1169     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1170        stack recursion. This gives a massive performance boost under BSD, but just
1171        a small improvement under Linux. However, it saves one field in the frame
1172        in all cases.
1174     6. Added more features from the forthcoming Perl 5.10:
1176        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1177            recursion call. It refers to the nth most recently opened parentheses.
1179        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1180            to be opened parentheses.
1182        (c) Conditions that refer to capturing parentheses can be specified
1183            relatively, for example, (?(-2)... or (?(+3)...
1185        (d) \K resets the start of the current match so that everything before
1186            is not part of it.
1188        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1190        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1191            reference syntax.
1193        (g) (?| introduces a group in which the numbering of parentheses in each
1194            alternative starts with the same number.
1196        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1198     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1201     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1202        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1203        for detecting groups that can match an empty string.
1205     9. A pattern with a very large number of alternatives (more than several
1206        hundred) was running out of internal workspace during the pre-compile
1207        phase, where pcre_compile() figures out how much memory will be needed. A
1208        bit of new cunning has reduced the workspace needed for groups with
1209        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1210        workspace instead of running out of the 4096 that are available.
1212    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1214    11. Applied patch from Google to remove an optimization that didn't quite work.
1215        The report of the bug said:
1217          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1218          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1219          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1221    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1222        it matched the wrong number of bytes.
1225    Version 7.1 24-Apr-07
1226    ---------------------
1228     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1229        that is more "standard", making use of automake and other Autotools. There
1230        is some re-arrangement of the files and adjustment of comments consequent
1231        on this.
1233     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1234        for recursive directory scanning broke on some systems because the files
1235        are not scanned in any specific order and on different systems the order
1236        was different. A call to "sort" has been inserted into RunGrepTest for the
1237        approprate test as a short-term fix. In the longer term there may be an
1238        alternative.
1240     3. I had an email from Eric Raymond about problems translating some of PCRE's
1241        man pages to HTML (despite the fact that I distribute HTML pages, some
1242        people do their own conversions for various reasons). The problems
1243        concerned the use of low-level troff macros .br and .in. I have therefore
1244        removed all such uses from the man pages (some were redundant, some could
1245        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1246        HTML has been updated to handle .nf/.fi and to complain if it encounters
1247        .br or .in.
1249     4. Updated comments in configure.ac that get placed in config.h.in and also
1250        arranged for config.h to be included in the distribution, with the name
1251        config.h.generic, for the benefit of those who have to compile without
1252        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1254     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1255        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1256        makevp.bat for the current PCRE, using the additional files
1257        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1259     6. A Windows user reported a minor discrepancy with test 2, which turned out
1260        to be caused by a trailing space on an input line that had got lost in his
1261        copy. The trailing space was an accident, so I've just removed it.
1263     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1264        that is needed.
1266     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1267        as "const" (a) because they are and (b) because it helps the PHP
1268        maintainers who have recently made a script to detect big data structures
1269        in the php code that should be moved to the .rodata section. I remembered
1270        to update Builducptable as well, so it won't revert if ucptable.h is ever
1271        re-created.
1273     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1274        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1275        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1276        support is not required. This saves 1.5-2K of code, which is important in
1277        some applications.
1279        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1280        so as not to refer to the tables, even though these functions will never be
1281        called when UTF-8 support is disabled. Otherwise there are problems with a
1282        shared library.
1284    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1286        (a) It was defining its arguments as char * instead of void *.
1288        (b) It was assuming that all moves were upwards in memory; this was true
1289            a long time ago when I wrote it, but is no longer the case.
1291        The emulated memove() is provided for those environments that have neither
1292        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1293        is clearly not the case, as these two bugs were recently reported.
1295    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1296        and Detrail to create the HTML documentation, the .txt form of the man
1297        pages, and it removes trailing spaces from listed files. It also creates
1298        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1299        case, it wraps all the #defines with #ifndefs. This script should be run
1300        before "make dist".
1302    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1303        with Unicode property support.
1305        (a) For a maximizing quantifier, if the two different cases of the
1306            character were of different lengths in their UTF-8 codings (there are
1307            some cases like this - I found 11), and the matching function had to
1308            back up over a mixture of the two cases, it incorrectly assumed they
1309            were both the same length.
1311        (b) When PCRE was configured to use the heap rather than the stack for
1312            recursion during matching, it was not correctly preserving the data for
1313            the other case of a UTF-8 character when checking ahead for a match
1314            while processing a minimizing repeat. If the check also involved
1315            matching a wide character, but failed, corruption could cause an
1316            erroneous result when trying to check for a repeat of the original
1317            character.
1319    13. Some tidying changes to the testing mechanism:
1321        (a) The RunTest script now detects the internal link size and whether there
1322            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1323            values substituted by "configure". (The RunGrepTest script already did
1324            this for UTF-8.) The configure.ac script no longer substitutes the
1325            relevant variables.
1327        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1328            with length and offset values. This means that the output is different
1329            for different internal link sizes. Test 2 is skipped for link sizes
1330            other than 2 because of this, bypassing the problem. Unfortunately,
1331            there was also a test in test 3 (the locale tests) that used /B and
1332            failed for link sizes other than 2. Rather than cut the whole test out,
1333            I have added a new /Z option to pcretest that replaces the length and
1334            offset values with spaces. This is now used to make test 3 independent
1335            of link size. (Test 2 will be tidied up later.)
1337    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1338        segmentation fault instead of returning the appropriate error message.
1340    15. In multiline mode when the newline sequence was set to "any", the pattern
1341        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1342        This doesn't seem right; it now treats the CRLF combination as the line
1343        ending, and so does not match in that case. It's only a pattern such as ^$
1344        that would hit this one: something like ^ABC$ would have failed after \r
1345        and then tried again after \r\n.
1347    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1348        in an attempt to make files that differ only in their line terminators
1349        compare equal. This works on Linux.
1351    17. Under certain error circumstances pcregrep might try to free random memory
1352        as it exited. This is now fixed, thanks to valgrind.
1354    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1355        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1356        was because its rules for how to advance for /g after matching an empty
1357        string at the end of a line did not allow for this case. They now check for
1358        it specially.
1360    20. pcretest is supposed to handle patterns and data of any length, by
1361        extending its buffers when necessary. It was getting this wrong when the
1362        buffer for a data line had to be extended.
1364    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1365        CRLF as a newline sequence.
1367    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1368        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1369        I have nevertheless tidied it up.
1371    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1373    24. Added a man page for pcre-config.
1376    Version 7.0 19-Dec-06
1377    ---------------------
1379     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1380        moving to gcc 4.1.1.
1382     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1383        sys/time.h, which is documented as needed for this function. It doesn't
1384        seem to matter on Linux, but it showed up on some releases of OS X.
1386     3. It seems that there are systems where bytes whose values are greater than
1387        127 match isprint() in the "C" locale. The "C" locale should be the
1388        default when a C program starts up. In most systems, only ASCII printing
1389        characters match isprint(). This difference caused the output from pcretest
1390        to vary, making some of the tests fail. I have changed pcretest so that:
1392        (a) When it is outputting text in the compiled version of a pattern, bytes
1393            other than 32-126 are always shown as hex escapes.
1395        (b) When it is outputting text that is a matched part of a subject string,
1396            it does the same, unless a different locale has been set for the match
1397            (using the /L modifier). In this case, it uses isprint() to decide.
1399     4. Fixed a major bug that caused incorrect computation of the amount of memory
1400        required for a compiled pattern when options that changed within the
1401        pattern affected the logic of the preliminary scan that determines the
1402        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1403        that the computed length was too small. The symptoms of this bug were
1404        either the PCRE error "internal error: code overflow" from pcre_compile(),
1405        or a glibc crash with a message such as "pcretest: free(): invalid next
1406        size (fast)". Examples of patterns that provoked this bug (shown in
1407        pcretest format) are:
1409          /(?-x: )/x
1410          /(?x)(?-x: \s*#\s*)/
1411          /((?i)[\x{c0}])/8
1412          /(?i:[\x{c0}])/8
1414        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1415        is now done differently.
1417     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1418        wrapper classes; (b) implement a new function in the C++ scanner that is
1419        more efficient than the old way of doing things because it avoids levels of
1420        recursion in the regex matching; (c) add a paragraph to the documentation
1421        for the FullMatch() function.
1423     6. The escape sequence \n was being treated as whatever was defined as
1424        "newline". Not only was this contrary to the documentation, which states
1425        that \n is character 10 (hex 0A), but it also went horribly wrong when
1426        "newline" was defined as CRLF. This has been fixed.
1428     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1429        was being set to -1 for the "end of line" case (supposedly a value that no
1430        character can have). Though this value is never used (the check for end of
1431        line is "zero bytes in current character"), it caused compiler complaints.
1432        I've changed it to 0xffffffff.
1434     8. In pcre_version.c, the version string was being built by a sequence of
1435        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1436        string (as it is for production releases) called a macro with an empty
1437        argument. The C standard says the result of this is undefined. The gcc
1438        compiler treats it as an empty string (which was what was wanted) but it is
1439        reported that Visual C gives an error. The source has been hacked around to
1440        avoid this problem.
1442     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1443        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1444        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1445        of them did).
1447    10. Originally, pcretest opened its input and output without "b"; then I was
1448        told that "b" was needed in some environments, so it was added for release
1449        5.0 to both the input and output. (It makes no difference on Unix-like
1450        systems.) Later I was told that it is wrong for the input on Windows. I've
1451        now abstracted the modes into two macros, to make it easier to fiddle with
1452        them, and removed "b" from the input mode under Windows.
1454    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1456    12. Added -help and --help to pcretest as an official way of being reminded
1457        of the options.
1459    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1460        and pcrecpp.cc because they annoy compilers at high warning levels.
1462    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1464    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1465        scripts are not C programs :-) and which was not noticed because it works
1466        on Linux.
1468    16. pcretest is supposed to handle any length of pattern and data line (as one
1469        line or as a continued sequence of lines) by extending its input buffer if
1470        necessary. This feature was broken for very long pattern lines, leading to
1471        a string of junk being passed to pcre_compile() if the pattern was longer
1472        than about 50K.
1474    17. I have done a major re-factoring of the way pcre_compile() computes the
1475        amount of memory needed for a compiled pattern. Previously, there was code
1476        that made a preliminary scan of the pattern in order to do this. That was
1477        OK when PCRE was new, but as the facilities have expanded, it has become
1478        harder and harder to keep it in step with the real compile phase, and there
1479        have been a number of bugs (see for example, 4 above). I have now found a
1480        cunning way of running the real compile function in a "fake" mode that
1481        enables it to compute how much memory it would need, while actually only
1482        ever using a few hundred bytes of working memory and without too many
1483        tests of the mode. This should make future maintenance and development
1484        easier. A side effect of this work is that the limit of 200 on the nesting
1485        depth of parentheses has been removed (though this was never a serious
1486        limitation, I suspect). However, there is a downside: pcre_compile() now
1487        runs more slowly than before (30% or more, depending on the pattern). I
1488        hope this isn't a big issue. There is no effect on runtime performance.
1490    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1491        newline (only possible for the last line of a file) and it was a
1492        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1494    19. Added additional timing features to pcretest. (1) The -tm option now times
1495        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1496        separate command line item, by a number that specifies the number of
1497        repeats to use when timing. The default is 50000; this gives better
1498        precision, but takes uncomfortably long for very large patterns.
1500    20. Extended pcre_study() to be more clever in cases where a branch of a
1501        subpattern has no definite first character. For example, (a*|b*)[cd] would
1502        previously give no result from pcre_study(). Now it recognizes that the
1503        first character must be a, b, c, or d.
1505    21. There was an incorrect error "recursive call could loop indefinitely" if
1506        a subpattern (or the entire pattern) that was being tested for matching an
1507        empty string contained only one non-empty item after a nested subpattern.
1508        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1509        incorrectly, because the \d was being skipped in the check.
1511    22. The pcretest program now has a new pattern option /B and a command line
1512        option -b, which is equivalent to adding /B to every pattern. This causes
1513        it to show the compiled bytecode, without the additional information that
1514        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1515        is the same as /B/I).
1517    23. A new optimization is now able automatically to treat some sequences such
1518        as a*b as a*+b. More specifically, if something simple (such as a character
1519        or a simple class like \d) has an unlimited quantifier, and is followed by
1520        something that cannot possibly match the quantified thing, the quantifier
1521        is automatically "possessified".
1523    24. A recursive reference to a subpattern whose number was greater than 39
1524        went wrong under certain circumstances in UTF-8 mode. This bug could also
1525        have affected the operation of pcre_study().
1527    25. Realized that a little bit of performance could be had by replacing
1528        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1530    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1532    27. Possessive quantifiers such as a++ were previously implemented by turning
1533        them into atomic groups such as ($>a+). Now they have their own opcodes,
1534        which improves performance. This includes the automatically created ones
1535        from 23 above.
1537    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1538        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1539        the first matched character to be a colon. This applied both to named and
1540        numbered groups.
1542    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1544    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1545        building PCRE on Windows easier, so I have included it in the distribution.
1547    31. There is now a check in pcretest against a ridiculously large number being
1548        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1549        loop, the loop is abandoned.
1551    32. Forward references to subpatterns in conditions such as (?(2)...) where
1552        subpattern 2 is defined later cause pcre_compile() to search forwards in
1553        the pattern for the relevant set of parentheses. This search went wrong
1554        when there were unescaped parentheses in a character class, parentheses
1555        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1557    33. "Subroutine" calls and backreferences were previously restricted to
1558        referencing subpatterns earlier in the regex. This restriction has now
1559        been removed.
1561    34. Added a number of extra features that are going to be in Perl 5.10. On the
1562        whole, these are just syntactic alternatives for features that PCRE had
1563        previously implemented using the Python syntax or my own invention. The
1564        other formats are all retained for compatibility.
1566        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1567            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1568            also .NET compatible.
1570        (b) A recursion or subroutine call to a named group can now be defined as
1571            (?&name) as well as (?P>name).
1573        (c) A backreference to a named group can now be defined as \k<name> or
1574            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1575            5.10, are also .NET compatible.
1577        (d) A conditional reference to a named group can now use the syntax
1578            (?(<name>) or (?('name') as well as (?(name).
1580        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1581            groups (named and numbered) that are never evaluated inline, but can be
1582            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1583            is always false. There may be only one alternative in such a group.
1585        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1586            as the simple (?(R). The condition is true only if the most recent
1587            recursion is that of the given number or name. It does not search out
1588            through the entire recursion stack.
1590        (g) The escape \gN or \g{N} has been added, where N is a positive or
1591            negative number, specifying an absolute or relative reference.
1593    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1594        some "unreachable code" warnings.
1596    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1597        things, this adds five new scripts.
1599    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1600        There were also incompatibilities regarding the handling of \Q..\E inside
1601        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1602        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1604    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1605        matches an empty string, and forcibly breaks the loop. There were bugs in
1606        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1607        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1608        separate and independent bugs (that affected different cases) have been
1609        fixed.
1611    39. Refactored the code to abolish the use of different opcodes for small
1612        capturing bracket numbers. This is a tidy that I avoided doing when I
1613        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1614        The new approach is not only tidier, it makes it possible to reduce the
1615        memory needed to fix the previous bug (38).
1617    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1618        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1619        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1620        mode.
1622    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1623        report.
1625    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1626        copy construction and assignment in the C++ wrapper.
1628    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1629        couple of bugs that could have given wrong results in the "--newline=crlf"
1630        case.
1632    44. Added a number of casts and did some reorganization of signed/unsigned int
1633        variables following suggestions from Dair Grant. Also renamed the variable
1634        "this" as "item" because it is a C++ keyword.
1636    45. Arranged for dftables to add
1638          #include "pcre_internal.h"
1640        to pcre_chartables.c because without it, gcc 4.x may remove the array
1641        definition from the final binary if PCRE is built into a static library and
1642        dead code stripping is activated.
1644    46. For an unanchored pattern, if a match attempt fails at the start of a
1645        newline sequence, and the newline setting is CRLF or ANY, and the next two
1646        characters are CRLF, advance by two characters instead of one.
1649    Version 6.7 04-Jul-06
1650    ---------------------
1652     1. In order to handle tests when input lines are enormously long, pcretest has
1653        been re-factored so that it automatically extends its buffers when
1654        necessary. The code is crude, but this _is_ just a test program. The
1655        default size has been increased from 32K to 50K.
1657     2. The code in pcre_study() was using the value of the re argument before
1658        testing it for NULL. (Of course, in any sensible call of the function, it
1659        won't be NULL.)
1661     3. The memmove() emulation function in pcre_internal.h, which is used on
1662        systems that lack both memmove() and bcopy() - that is, hardly ever -
1663        was missing a "static" storage class specifier.
1665     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1666        containing an extended class (one that cannot be represented by a bitmap
1667        because it contains high-valued characters or Unicode property items, e.g.
1668        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1669        pattern, but PCRE should not loop if you do not (it no longer does).
1670        [Detail: two cases were found: (a) a repeated subpattern containing an
1671        extended class; (b) a recursive reference to a subpattern that followed a
1672        previous extended class. It wasn't skipping over the extended class
1673        correctly when UTF-8 mode was not set.]
1675     5. A negated single-character class was not being recognized as fixed-length
1676        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1677        compile error "lookbehind assertion is not fixed length".
1679     6. The RunPerlTest auxiliary script was showing an unexpected difference
1680        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1681        write a Perl script that can interpret lines of an input file either as
1682        byte characters or as UTF-8, which is what "perltest" was being required to
1683        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1684        can't do is switch easily at run time between having the "use utf8;" pragma
1685        or not. In the end, I fudged it by using the RunPerlTest script to insert
1686        "use utf8;" explicitly for the UTF-8 tests.
1688     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1689        the end of the subject string, contrary to the documentation and to what
1690        Perl does. This was true of both matching functions. Now it matches only at
1691        the start of the subject and immediately after *internal* newlines.
1693     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1694        a pointer to an int instead of a pointer to an unsigned long int. This
1695        caused problems on 64-bit systems.
1697     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1698        instance of the 'standard' template library not being so standard".
1700    10. There was no check on the number of named subpatterns nor the maximum
1701        length of a subpattern name. The product of these values is used to compute
1702        the size of the memory block for a compiled pattern. By supplying a very
1703        long subpattern name and a large number of named subpatterns, the size
1704        computation could be caused to overflow. This is now prevented by limiting
1705        the length of names to 32 characters, and the number of named subpatterns
1706        to 10,000.
1708    11. Subpatterns that are repeated with specific counts have to be replicated in
1709        the compiled pattern. The size of memory for this was computed from the
1710        length of the subpattern and the repeat count. The latter is limited to
1711        65535, but there was no limit on the former, meaning that integer overflow
1712        could in principle occur. The compiled length of a repeated subpattern is
1713        now limited to 30,000 bytes in order to prevent this.
1715    12. Added the optional facility to have named substrings with the same name.
1717    13. Added the ability to use a named substring as a condition, using the
1718        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1719        are numbers (not recommended). Forward references are permitted.
1721    14. Added forward references in named backreferences (if you see what I mean).
1723    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1724        pattern could run off the end of the subject. For example, the pattern
1725        "(?s)(.{1,5})"8 did this with the subject "ab".
1727    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1728        PCRE_CASELESS was set when matching characters that were quantified with ?
1729        or *.
1731    17. A character class other than a single negated character that had a minimum
1732        but no maximum quantifier - for example [ab]{6,} - was not handled
1733        correctly by pce_dfa_exec(). It would match only one character.
1735    18. A valid (though odd) pattern that looked like a POSIX character
1736        class but used an invalid character after [ (for example [[,abc,]]) caused
1737        pcre_compile() to give the error "Failed: internal error: code overflow" or
1738        in some cases to crash with a glibc free() error. This could even happen if
1739        the pattern terminated after [[ but there just happened to be a sequence of
1740        letters, a binary zero, and a closing ] in the memory that followed.
1742    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1743        over the years. Originally (before any Unicode support), just the bottom 8
1744        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1745        output from "man perlunicode" includes this:
1747          The regular expression compiler produces polymorphic opcodes.  That
1748          is, the pattern adapts to the data and automatically switches to
1749          the Unicode character scheme when presented with Unicode data--or
1750          instead uses a traditional byte scheme when presented with byte
1751          data.
1753        Sadly, a wide octal escape does not cause a switch, and in a string with
1754        no other multibyte characters, these octal escapes are treated as before.
1755        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1756        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1757        Unicode string.
1759        I have not perpetrated such confusion in PCRE. Up till now, it took just
1760        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1761        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1762        translate to the appropriate multibyte character.
1764    29. Applied some refactoring to reduce the number of warnings from Microsoft
1765        and Borland compilers. This has included removing the fudge introduced
1766        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1767        a warning about an unused variable.
1769    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1770        characters since release 4.0, because Perl (from release 5.004) does not.
1771        [Or at least, is documented not to: some releases seem to be in conflict
1772        with the documentation.] However, when a pattern was studied with
1773        pcre_study() and all its branches started with \s, PCRE still included VT
1774        as a possible starting character. Of course, this did no harm; it just
1775        caused an unnecessary match attempt.
1777    22. Removed a now-redundant internal flag bit that recorded the fact that case
1778        dependency changed within the pattern. This was once needed for "required
1779        byte" processing, but is no longer used. This recovers a now-scarce options
1780        bit. Also moved the least significant internal flag bit to the most-
1781        significant bit of the word, which was not previously used (hangover from
1782        the days when it was an int rather than a uint) to free up another bit for
1783        the future.
1785    23. Added support for CRLF line endings as well as CR and LF. As well as the
1786        default being selectable at build time, it can now be changed at runtime
1787        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1788        specify that it is scanning data with non-default line endings.
1790    24. Changed the definition of CXXLINK to make it agree with the definition of
1791        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1793    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1794        recursions. This makes a big different to stack usage for some patterns.
1796    26. If a subpattern containing a named recursion or subroutine reference such
1797        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1798        the space required for the compiled pattern went wrong and gave too small a
1799        value. Depending on the environment, this could lead to "Failed: internal
1800        error: code overflow at offset 49" or "glibc detected double free or
1801        corruption" errors.
1803    27. Applied patches from Google (a) to support the new newline modes and (b) to
1804        advance over multibyte UTF-8 characters in GlobalReplace.
1806    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1807        difference for some implementation of PCRE in some Windows version.
1809    29. Added some extra testing facilities to pcretest:
1811        \q<number>   in a data line sets the "match limit" value
1812        \Q<number>   in a data line sets the "match recursion limt" value
1813        -S <number>  sets the stack size, where <number> is in megabytes
1815        The -S option isn't available for Windows.
1818    Version 6.6 06-Feb-06
1819    ---------------------
1821     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1822        in pcreposix.h. I have copied the definition from pcre.h.
1824     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1825        because pcre.h is no longer a built file.
1827     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1828        not normally included in the compiled code.
1831    Version 6.5 01-Feb-06
1832    ---------------------
1834     1. When using the partial match feature with pcre_dfa_exec(), it was not
1835        anchoring the second and subsequent partial matches at the new starting
1836        point. This could lead to incorrect results. For example, with the pattern
1837        /1234/, partially matching against "123" and then "a4" gave a match.
1839     2. Changes to pcregrep:
1841        (a) All non-match returns from pcre_exec() were being treated as failures
1842            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1843            error message is output. Some extra information is given for the
1844            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1845            probably the only errors that are likely to be caused by users (by
1846            specifying a regex that has nested indefinite repeats, for instance).
1847            If there are more than 20 of these errors, pcregrep is abandoned.
1849        (b) A binary zero was treated as data while matching, but terminated the
1850            output line if it was written out. This has been fixed: binary zeroes
1851            are now no different to any other data bytes.
1853        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1854            used to set a locale for matching. The --locale=xxxx long option has
1855            been added (no short equivalent) to specify a locale explicitly on the
1856            pcregrep command, overriding the environment variables.
1858        (d) When -B was used with -n, some line numbers in the output were one less
1859            than they should have been.
1861        (e) Added the -o (--only-matching) option.
1863        (f) If -A or -C was used with -c (count only), some lines of context were
1864            accidentally printed for the final match.
1866        (g) Added the -H (--with-filename) option.
1868        (h) The combination of options -rh failed to suppress file names for files
1869            that were found from directory arguments.
1871        (i) Added the -D (--devices) and -d (--directories) options.
1873        (j) Added the -F (--fixed-strings) option.
1875        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1877        (l) Added the --colo(u)r option.
1879        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1880            is not present by default.
1882     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1883        items such as (?R) or (?1), when the recursion could match a number of
1884        alternatives. If it matched one of the alternatives, but subsequently,
1885        outside the recursion, there was a failure, the code tried to back up into
1886        the recursion. However, because of the way PCRE is implemented, this is not
1887        possible, and the result was an incorrect result from the match.
1889        In order to prevent this happening, the specification of recursion has
1890        been changed so that all such subpatterns are automatically treated as
1891        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1893     4. I had overlooked the fact that, in some locales, there are characters for
1894        which isalpha() is true but neither isupper() nor islower() are true. In
1895        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1896        and ordfeminine) are like this. This affected the treatment of \w and \W
1897        when they appeared in character classes, but not when they appeared outside
1898        a character class. The bit map for "word" characters is now created
1899        separately from the results of isalnum() instead of just taking it from the
1900        upper, lower, and digit maps. (Plus the underscore character, of course.)
1902     5. The above bug also affected the handling of POSIX character classes such as
1903        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1904        permanent tables. Instead, the bit maps for such a class were previously
1905        created as the appropriate unions of the upper, lower, and digit bitmaps.
1906        Now they are created by subtraction from the [[:word:]] class, which has
1907        its own bitmap.
1909     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1910        It is created by subtracting the vertical space characters (\x09, \x0a,
1911        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1912        subtraction was done in the overall bitmap for a character class, meaning
1913        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1914        be recognized. This bug has been fixed.
1916     7. Patches from the folks at Google:
1918          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1919          real life, but is still worth protecting against".
1921          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1922          regular expressions".
1924          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1925          have it.
1927          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1928          "configure" and the latter not, in order to fix a problem somebody had
1929          with compiling the Arg class on HP-UX.
1931          (e) Improve the error-handling of the C++ wrapper a little bit.
1933          (f) New tests for checking recursion limiting.
1935     8. The pcre_memmove() function, which is used only if the environment does not
1936        have a standard memmove() function (and is therefore rarely compiled),
1937        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1938        returning a result (though PCRE never actually uses the result).
1940     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1941        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1942        returned instead of calling malloc() with an overflowing number that would
1943        most likely cause subsequent chaos.
1945    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1947    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1948        with this option is matched, the nmatch and pmatch options of regexec() are
1949        ignored.
1951    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1952        provided in case anyone wants to the the POSIX interface with UTF-8
1953        strings.
1955    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1956        C++ linking (needed for some HP-UX environments).
1958    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1959        (unused parameter) and in the pcre_printint() function (omitted "default"
1960        switch label when the default is to do nothing).
1962    15. Added some code to make it possible, when PCRE is compiled as a C++
1963        library, to replace subject pointers for pcre_exec() with a smart pointer
1964        class, thus making it possible to process discontinuous strings.
1966    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1967        much the same function. They were added by different people who were trying
1968        to make PCRE easy to compile on non-Unix systems. It has been suggested
1969        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1970        for compiling on Windows systems. I have therefore replaced it with
1971        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1972        defaults to "extern" for C or "extern C" for C++, which works fine on
1973        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1974        SCOPE with something explicit in config.h. In addition:
1976        (a) pcreposix.h still had just "extern" instead of either of these macros;
1977            I have replaced it with PCRE_DATA_SCOPE.
1979        (b) Functions such as _pcre_xclass(), which are internal to the library,
1980            but external in the C sense, all had PCRE_EXPORT in their definitions.
1981            This is apparently wrong for the Windows case, so I have removed it.
1982            (It makes no difference on Unix-like systems.)
1984    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1985        of recursive calls to match(). This is different to MATCH_LIMIT because
1986        that limits the total number of calls to match(), not all of which increase
1987        the depth of recursion. Limiting the recursion depth limits the amount of
1988        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1989        when PCRE is compiled, and changed at run time. A patch from Google adds
1990        this functionality to the C++ interface.
1992    18. Changes to the handling of Unicode character properties:
1994        (a) Updated the table to Unicode 4.1.0.
1996        (b) Recognize characters that are not in the table as "Cn" (undefined).
1998        (c) I revised the way the table is implemented to a much improved format
1999            which includes recognition of ranges. It now supports the ranges that
2000            are defined in UnicodeData.txt, and it also amalgamates other
2001            characters into ranges. This has reduced the number of entries in the
2002            table from around 16,000 to around 3,000, thus reducing its size
2003            considerably. I realized I did not need to use a tree structure after
2004            all - a binary chop search is just as efficient. Having reduced the
2005            number of entries, I extended their size from 6 bytes to 8 bytes to
2006            allow for more data.
2008        (d) Added support for Unicode script names via properties such as \p{Han}.
2010    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2011        matching that character.
2013    20. When matching a repeated Unicode property with a minimum greater than zero,
2014        (for example \pL{2,}), PCRE could look past the end of the subject if it
2015        reached it while seeking the minimum number of characters. This could
2016        happen only if some of the characters were more than one byte long, because
2017        there is a check for at least the minimum number of bytes.
2019    21. Refactored the implementation of \p and \P so as to be more general, to
2020        allow for more different types of property in future. This has changed the
2021        compiled form incompatibly. Anybody with saved compiled patterns that use
2022        \p or \P will have to recompile them.
2024    22. Added "Any" and "L&" to the supported property types.
2026    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2027        but give a compile time error if the value is greater than 0xff.
2029    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2030        accidentally not being installed or uninstalled.
2032    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2033        made were to insert the current release number. This seemed silly, because
2034        it made things harder for people building PCRE on systems that don't run
2035        "configure". I have turned pcre.h into a distributed file, no longer built
2036        by "configure", with the version identification directly included. There is
2037        no longer a pcre.h.in file.
2039        However, this change necessitated a change to the pcre-config script as
2040        well. It is built from pcre-config.in, and one of the substitutions was the
2041        release number. I have updated configure.ac so that ./configure now finds
2042        the release number by grepping pcre.h.
2044    26. Added the ability to run the tests under valgrind.
2047  Version 6.4 05-Sep-05  Version 6.4 05-Sep-05
2048  ---------------------  ---------------------

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