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revision 61 by nigel, Sat Feb 24 21:39:58 2007 UTC revision 459 by ph10, Sun Oct 4 09:21:39 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 3.0 02-Jan-02  Version 8.00 ??-???-??
5    ----------------------
7    1.  The table for translating pcre_compile() error codes into POSIX error codes
8        was out-of-date, and there was no check on the pcre_compile() error code
9        being within the table. This could lead to an OK return being given in
10        error.
12    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
13        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14        in a Windows environment.
16    3.  The pcregrep --count option prints the count for each file even when it is
17        zero, as does GNU grep. However, pcregrep was also printing all files when
18        --files-with-matches was added. Now, when both options are given, it prints
19        counts only for those files that have at least one match. (GNU grep just
20        prints the file name in this circumstance, but including the count seems
21        more useful - otherwise, why use --count?) Also ensured that the
22        combination -clh just lists non-zero counts, with no names.
24    4.  The long form of the pcregrep -F option was incorrectly implemented as
25        --fixed_strings instead of --fixed-strings. This is an incompatible change,
26        but it seems right to fix it, and I didn't think it was worth preserving
27        the old behaviour.
29    5.  The command line items --regex=pattern and --regexp=pattern were not
30        recognized by pcregrep, which required --regex pattern or --regexp pattern
31        (with a space rather than an '='). The man page documented the '=' forms,
32        which are compatible with GNU grep; these now work.
34    6.  No libpcreposix.pc file was created for pkg-config; there was just
35        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
37    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
38        when UCP support is not needed, by modifying the Python script that
39        generates it from Unicode data files. This should not matter if the module
40        is correctly used as a library, but I received one complaint about 50K of
41        unwanted data. My guess is that the person linked everything into his
42        program rather than using a library. Anyway, it does no harm.
44    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
45        was a minimum greater than 1 for a wide character in a possessive
46        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
47        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
48        character. Chaos in the form of incorrect output or a compiling loop could
49        result.
51    9.  The restrictions on what a pattern can contain when partial matching is
52        requested for pcre_exec() have been removed. All patterns can now be
53        partially matched by this function. In addition, if there are at least two
54        slots in the offset vector, the offset of the earliest inspected character
55        for the match and the offset of the end of the subject are set in them when
56        PCRE_ERROR_PARTIAL is returned.
58    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
59        synonymous with PCRE_PARTIAL, for backwards compatibility, and
60        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
61        and may be more useful for multi-segment matching, especially with
62        pcre_exec().
64    11. Partial matching with pcre_exec() is now more intuitive. A partial match
65        used to be given if ever the end of the subject was reached; now it is
66        given only if matching could not proceed because another character was
67        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
68        string "Z", which now yields "no match" instead of "partial match". In the
69        case of pcre_dfa_exec(), "no match" is given if every matching path for the
70        final character ended with (*FAIL).
72    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
73        if the pattern had a "must contain" character that was already found in the
74        earlier partial match, unless partial matching was again requested. For
75        example, with the pattern /dog.(body)?/, the "must contain" character is
76        "g". If the first part-match was for the string "dog", restarting with
77        "sbody" failed. This bug has been fixed.
79    13. The string returned by pcre_dfa_exec() after a partial match has been
80        changed so that it starts at the first inspected character rather than the
81        first character of the match. This makes a difference only if the pattern
82        starts with a lookbehind assertion or \b or \B (\K is not supported by
83        pcre_dfa_exec()). It's an incompatible change, but it makes the two
84        matching functions compatible, and I think it's the right thing to do.
86    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
87        so that the demonstration program is easily available in environments where
88        PCRE has not been installed from source.
90    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
91        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
92        library.
94    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
95        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
96        is not the first non-POSIX option to be added. Clearly some people find
97        these options useful.
99    17. If a caller to the POSIX matching function regexec() passes a non-zero
100        value for nmatch with a NULL value for pmatch, the value of
101        nmatch is forced to zero.
103    18. RunGrepTest did not have a test for the availability of the -u option of
104        the diff command, as RunTest does. It now checks in the same way as
105        RunTest, and also checks for the -b option.
107    19. If an odd number of negated classes containing just a single character
108        interposed, within parentheses, between a forward reference to a named
109        subpattern and the definition of the subpattern, compilation crashed with
110        an internal error, complaining that it could not find the referenced
111        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
112        [The bug was that it was starting one character too far in when skipping
113        over the character class, thus treating the ] as data rather than
114        terminating the class. This meant it could skip too much.]
116    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
117        /g option in pcretest when the pattern contains \K, which makes it possible
118        to have an empty string match not at the start, even when the pattern is
119        anchored. Updated pcretest and pcredemo to use this option.
121    21. If the maximum number of capturing subpatterns in a recursion was greater
122        than the maximum at the outer level, the higher number was returned, but
123        with unset values at the outer level. The correct (outer level) value is
124        now given.
126    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
127        PCRE did not set those parentheses (unlike Perl). I have now found a way to
128        make it do so. The string so far is captured, making this feature
129        compatible with Perl.
131    23. The tests have been re-organized, adding tests 11 and 12, to make it
132        possible to check the Perl 5.10 features against Perl 5.10.
134    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
135        pattern matches a fixed length string. PCRE did not allow this; now it
136        does. Neither allows recursion.
138    25. I finally figured out how to implement a request to provide the minimum
139        length of subject string that was needed in order to match a given pattern.
140        (It was back references and recursion that I had previously got hung up
141        on.) This code has now been added to pcre_study(); it finds a lower bound
142        to the length of subject needed. It is not necessarily the greatest lower
143        bound, but using it to avoid searching strings that are too short does give
144        some useful speed-ups. The value is available to calling programs via
145        pcre_fullinfo().
147    26. While implementing 25, I discovered to my embarrassment that pcretest had
148        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
149        study optimizations had never been tested with that matching function.
150        Oops. What is worse, even when it was passed study data, there was a bug in
151        pcre_dfa_exec() that meant it never actually used it. Double oops. There
152        were also very few tests of studied patterns with pcre_dfa_exec().
154    27. If (?| is used to create subpatterns with duplicate numbers, they are now
155        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
156        on the other side of the coin, they are no longer allowed to have different
157        names, because these cannot be distinguished in PCRE, and this has caused
158        confusion. (This is a difference from Perl.)
160    28. When duplicate subpattern names are present (necessarily with different
161        numbers, as required by 27 above), and a test is made by name in a
162        conditional pattern, either for a subpattern having been matched, or for
163        recursion in such a pattern, all the associated numbered subpatterns are
164        tested, and the overall condition is true if the condition is true for any
165        one of them. This is the way Perl works, and is also more like the way
166        testing by number works.
169    Version 7.9 11-Apr-09
170    ---------------------
172    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
173        (pcretest), all targets were linked against these libraries. This included
174        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
175        libraries. This caused unwanted dependencies to be created. This problem
176        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
177        pcretest is linked with readline.
179    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
180        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
181        moved outside it again, because FALSE and TRUE are already defined in AIX,
182        but BOOL is not.
184    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
185        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
187    4.  The pcregrep documentation said spaces were inserted as well as colons (or
188        hyphens) following file names and line numbers when outputting matching
189        lines. This is not true; no spaces are inserted. I have also clarified the
190        wording for the --colour (or --color) option.
192    5.  In pcregrep, when --colour was used with -o, the list of matching strings
193        was not coloured; this is different to GNU grep, so I have changed it to be
194        the same.
196    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
197        each matching line was coloured. Now it goes on to look for further matches
198        of any of the test patterns, which is the same behaviour as GNU grep.
200    7.  A pattern that could match an empty string could cause pcregrep to loop; it
201        doesn't make sense to accept an empty string match in pcregrep, so I have
202        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
203        seems to be how GNU grep behaves.
205    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
206        start or after a newline", because the conditional assertion was not being
207        correctly handled. The rule now is that both the assertion and what follows
208        in the first alternative must satisfy the test.
210    9.  If auto-callout was enabled in a pattern with a conditional group whose
211        condition was an assertion, PCRE could crash during matching, both with
212        pcre_exec() and pcre_dfa_exec().
214    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
215        used for matching.
217    11. Unicode property support in character classes was not working for
218        characters (bytes) greater than 127 when not in UTF-8 mode.
220    12. Added the -M command line option to pcretest.
222    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
224    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
226    16. Added comments and documentation about mis-use of no_arg in the C++
227        wrapper.
229    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
230        from Martin Jerabek that uses macro names for all relevant character and
231        string constants.
233    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
234        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
235        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
236        these, but not everybody uses configure.
238    19. A conditional group that had only one branch was not being correctly
239        recognized as an item that could match an empty string. This meant that an
240        enclosing group might also not be so recognized, causing infinite looping
241        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
242        with the subject "ab", where knowledge that the repeated group can match
243        nothing is needed in order to break the loop.
245    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
246        exec(), but without supplying a callout function, matching went wrong.
248    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
249        leak if the size of the offset vector was greater than 30. When the vector
250        is smaller, the saved offsets during recursion go onto a local stack
251        vector, but for larger vectors malloc() is used. It was failing to free
252        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
253        error, in fact).
255    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
256        heapframe that is used only when UTF-8 support is enabled. This caused no
257        problem, but was untidy.
259    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
260        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
261        included within another project.
263    24. Steven Van Ingelgem's patches to add more options to the CMake support,
264        slightly modified by me:
266          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
267              not building pcregrep.
269          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
270              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
272    25. Forward references, both numeric and by name, in patterns that made use of
273        duplicate group numbers, could behave incorrectly or give incorrect errors,
274        because when scanning forward to find the reference group, PCRE was not
275        taking into account the duplicate group numbers. A pattern such as
276        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
278    26. Changed a few more instances of "const unsigned char *" to USPTR, making
279        the feature of a custom pointer more persuasive (as requested by a user).
281    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
282        pcretest.c, inside #ifndefs, because it seems they are sometimes already
283        pre-defined.
285    28. Added support for (*UTF8) at the start of a pattern.
287    29. Arrange for flags added by the "release type" setting in CMake to be shown
288        in the configuration summary.
291    Version 7.8 05-Sep-08
292    ---------------------
294    1.  Replaced UCP searching code with optimized version as implemented for Ad
295        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
296        stage table and inline lookup instead of a function, giving speed ups of 2
297        to 5 times on some simple patterns that I tested. Permission was given to
298        distribute the MultiStage2.py script that generates the tables (it's not in
299        the tarball, but is in the Subversion repository).
301    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
302        scripts.
304    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
305        a group with a zero qualifier. The result of the study could be incorrect,
306        or the function might crash, depending on the pattern.
308    4.  Caseless matching was not working for non-ASCII characters in back
309        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
310        It now works when Unicode Property Support is available.
312    5.  In pcretest, an escape such as \x{de} in the data was always generating
313        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
314        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
315        truncation.
317    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
319    7.  Added two (int) casts to pcregrep when printing the difference of two
320        pointers, in case they are 64-bit values.
322    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
323        test 2 if it fails.
325    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
326        and a #define of that name to empty if it is not externally set. This is to
327        allow users of MSVC to set it if necessary.
329    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
330        the convenience functions in the pcre_get.c source file.
332    11. An option change at the start of a pattern that had top-level alternatives
333        could cause overwriting and/or a crash. This command provoked a crash in
334        some environments:
336          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
338        This potential security problem was recorded as CVE-2008-2371.
340    12. For a pattern where the match had to start at the beginning or immediately
341        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
342        pcre_dfa_exec() could read past the end of the passed subject if there was
343        no match. To help with detecting such bugs (e.g. with valgrind), I modified
344        pcretest so that it places the subject at the end of its malloc-ed buffer.
346    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
347        exec() might read past the end of the data buffer in UTF-8 mode.
349    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
350        the data contained the byte 0x85 as part of a UTF-8 character within its
351        first line. This applied both to normal and DFA matching.
353    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
354        /^[^d]*?$/8 failed to match "abc".
356    16. Added a missing copyright notice to pcrecpp_internal.h.
358    17. Make it more clear in the documentation that values returned from
359        pcre_exec() in ovector are byte offsets, not character counts.
361    18. Tidied a few places to stop certain compilers from issuing warnings.
363    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
364        supplied by Stefan Weber. I made a further small update for 7.8 because
365        there is a change of source arrangements: the pcre_searchfuncs.c module is
366        replaced by pcre_ucd.c.
369    Version 7.7 07-May-08
370    ---------------------
372    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
373        a string to a long long, pretend we don't even have a long long." This is
374        done by checking for the strtoq, strtoll, and _strtoi64 functions.
376    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
377        pre-7.6 versions, which defined a global no_arg variable instead of putting
378        it in the RE class. (See also #8 below.)
380    3.  Remove a line of dead code, identified by coverity and reported by Nuno
381        Lopes.
383    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
385        (1) The include/exclude patterns were being applied to the whole pathnames
386            of files, instead of just to the final components.
388        (2) If there was more than one level of directory, the subdirectories were
389            skipped unless they satisfied the include/exclude conditions. This is
390            inconsistent with GNU grep (and could even be seen as contrary to the
391            pcregrep specification - which I improved to make it absolutely clear).
392            The action now is always to scan all levels of directory, and just
393            apply the include/exclude patterns to regular files.
395    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
396        --exclude_dir in the tests to avoid scanning .svn directories.
398    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
399        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
400        doesn't support NULs in patterns.
402    7.  Added some missing "const"s to declarations of static tables in
403        pcre_compile.c and pcre_dfa_exec.c.
405    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
406        caused by fix #2  above. (Subsequently also a second patch to fix the
407        first patch. And a third patch - this was a messy problem.)
409    9.  Applied Craig's patch to remove the use of push_back().
411    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
412        matching function regexec().
414    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
415        which, however, unlike Perl's \g{...}, are subroutine calls, not back
416        references. PCRE supports relative numbers with this syntax (I don't think
417        Oniguruma does).
419    12. Previously, a group with a zero repeat such as (...){0} was completely
420        omitted from the compiled regex. However, this means that if the group
421        was called as a subroutine from elsewhere in the pattern, things went wrong
422        (an internal error was given). Such groups are now left in the compiled
423        pattern, with a new opcode that causes them to be skipped at execution
424        time.
426    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
427        to the way PCRE behaves:
429        (a) A lone ] character is dis-allowed (Perl treats it as data).
431        (b) A back reference to an unmatched subpattern matches an empty string
432            (Perl fails the current match path).
434        (c) A data ] in a character class must be notated as \] because if the
435            first data character in a class is ], it defines an empty class. (In
436            Perl it is not possible to have an empty class.) The empty class []
437            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
438            The negative empty class [^] matches any one character, independently
439            of the DOTALL setting.
441    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
442        non-existent subpattern following a character class starting with ']' and
443        containing () gave an internal compiling error instead of "reference to
444        non-existent subpattern". Fortunately, when the pattern did exist, the
445        compiled code was correct. (When scanning forwards to check for the
446        existencd of the subpattern, it was treating the data ']' as terminating
447        the class, so got the count wrong. When actually compiling, the reference
448        was subsequently set up correctly.)
450    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
451        it was being rejected as not supported by pcre_dfa_exec(), even though
452        other assertions are supported. I have made pcre_dfa_exec() support
453        (*FAIL).
455    16. The implementation of 13c above involved the invention of a new opcode,
456        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
457        cannot be changed at match time, I realized I could make a small
458        improvement to matching performance by compiling OP_ALLANY instead of
459        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
460        on the OP_ANY path.
462    17. Compiling pcretest on Windows with readline support failed without the
463        following two fixes: (1) Make the unistd.h include conditional on
464        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
466    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
467        ncurses library to be included for pcretest when ReadLine support is
468        requested, but also to allow for it to be overridden. This patch came from
469        Daniel Bergström.
471    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
472        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
473        any errors with the current Unicode tables. Thanks to Peter Kankowski for
474        spotting this.
477    Version 7.6 28-Jan-08
478    ---------------------
480    1.  A character class containing a very large number of characters with
481        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
482        overflow.
484    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
485        HAVE_LONG_LONG is not defined.
487    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
488        bring them up to date and include new features. This patch includes:
490        - Fixed PH's badly added libz and libbz2 support.
491        - Fixed a problem with static linking.
492        - Added pcredemo. [But later removed - see 7 below.]
493        - Fixed dftables problem and added an option.
494        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
495            HAVE_LONG_LONG.
496        - Added readline support for pcretest.
497        - Added an listing of the option settings after cmake has run.
499    4.  A user submitted a patch to Makefile that makes it easy to create
500        "pcre.dll" under mingw when using Configure/Make. I added stuff to
501        Makefile.am that cause it to include this special target, without
502        affecting anything else. Note that the same mingw target plus all
503        the other distribution libraries and programs are now supported
504        when configuring with CMake (see 6 below) instead of with
505        Configure/Make.
507    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
508        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
509        exported in the Windows port". It has not yet been confirmed that the patch
510        solves the problem, but it does no harm.
512    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
513        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
514        with CMake, and also correct the comment about stack recursion.
516    7.  Remove the automatic building of pcredemo from the ./configure system and
517        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
518        of a program that users should build themselves after PCRE is installed, so
519        building it automatically is not really right. What is more, it gave
520        trouble in some build environments.
522    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
525    Version 7.5 10-Jan-08
526    ---------------------
528    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
529        values in parens when parsing an RE using the C++ wrapper."
531    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
532        Characters greater than 255 were excluded from the class instead of being
533        included.
535    3.  The same bug as (2) above applied to negated POSIX classes such as
536        [:^space:].
538    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
539        defined or documented. It seems to have been a typo for PCRE_STATIC, so
540        I have changed it.
542    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
543        first named subpattern) and a construct such as (?&a) would reference the
544        first named subpattern whose name started with "a" (in other words, the
545        length check was missing). Both these problems are fixed. "Subpattern name
546        expected" is now given for (?&) (a zero-length name), and this patch also
547        makes it give the same error for \k'' (previously it complained that that
548        was a reference to a non-existent subpattern).
550    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
551        this is right because (?- can be followed by option settings as well as by
552        digits. I have, however, made the messages clearer.
554    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
555        than the number used in the conditional) now cause a compile-time error.
556        This is actually not compatible with Perl, which accepts such patterns, but
557        treats the conditional as always being FALSE (as PCRE used to), but it
558        seems to me that giving a diagnostic is better.
560    8.  Change "alphameric" to the more common word "alphanumeric" in comments
561        and messages.
563    9.  Fix two occurrences of "backslash" in comments that should have been
564        "backspace".
566    10. Remove two redundant lines of code that can never be obeyed (their function
567        was moved elsewhere).
569    11. The program that makes PCRE's Unicode character property table had a bug
570        which caused it to generate incorrect table entries for sequences of
571        characters that have the same character type, but are in different scripts.
572        It amalgamated them into a single range, with the script of the first of
573        them. In other words, some characters were in the wrong script. There were
574        thirteen such cases, affecting characters in the following ranges:
576          U+002b0 - U+002c1
577          U+0060c - U+0060d
578          U+0061e - U+00612
579          U+0064b - U+0065e
580          U+0074d - U+0076d
581          U+01800 - U+01805
582          U+01d00 - U+01d77
583          U+01d9b - U+01dbf
584          U+0200b - U+0200f
585          U+030fc - U+030fe
586          U+03260 - U+0327f
587          U+0fb46 - U+0fbb1
588          U+10450 - U+1049d
590    12. The -o option (show only the matching part of a line) for pcregrep was not
591        compatible with GNU grep in that, if there was more than one match in a
592        line, it showed only the first of them. It now behaves in the same way as
593        GNU grep.
595    13. If the -o and -v options were combined for pcregrep, it printed a blank
596        line for every non-matching line. GNU grep prints nothing, and pcregrep now
597        does the same. The return code can be used to tell if there were any
598        non-matching lines.
600    14. Added --file-offsets and --line-offsets to pcregrep.
602    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
603        infinitely looping recursion. The bug was that positive lookaheads were not
604        being skipped when checking for a possible empty match (negative lookaheads
605        and both kinds of lookbehind were skipped).
607    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
608        inclusion of <windows.h> to before rather than after the definition of
609        INVALID_FILE_ATTRIBUTES (patch from David Byron).
611    17. Specifying a possessive quantifier with a specific limit for a Unicode
612        character property caused pcre_compile() to compile bad code, which led at
613        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
614        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
615        caused the error; without that there was no problem.
617    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
619    19. Added --enable-pcretest-libreadline.
621    20. In pcrecpp.cc, the variable 'count' was incremented twice in
622        RE::GlobalReplace(). As a result, the number of replacements returned was
623        double what it should be. I removed one of the increments, but Craig sent a
624        later patch that removed the other one (the right fix) and added unit tests
625        that check the return values (which was not done before).
627    21. Several CMake things:
629        (1) Arranged that, when cmake is used on Unix, the libraries end up with
630            the names libpcre and libpcreposix, not just pcre and pcreposix.
632        (2) The above change means that pcretest and pcregrep are now correctly
633            linked with the newly-built libraries, not previously installed ones.
637    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
638        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
639        UTF-8 newline character). The key issue is that the pattern starts .*;
640        this means that the match must be either at the beginning, or after a
641        newline. The bug was in the code for advancing after a failed match and
642        checking that the new position followed a newline. It was not taking
643        account of UTF-8 characters correctly.
645    23. PCRE was behaving differently from Perl in the way it recognized POSIX
646        character classes. PCRE was not treating the sequence [:...:] as a
647        character class unless the ... were all letters. Perl, however, seems to
648        allow any characters between [: and :], though of course it rejects as
649        unknown any "names" that contain non-letters, because all the known class
650        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
651        for example, whereas PCRE did not - it did not recognize a POSIX character
652        class. This seemed a bit dangerous, so the code has been changed to be
653        closer to Perl. The behaviour is not identical to Perl, because PCRE will
654        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
655        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
656        Perl does, and where it didn't before.
658    24. Rewrite so as to remove the single use of %n from pcregrep because in some
659        Windows environments %n is disabled by default.
662    Version 7.4 21-Sep-07
663    ---------------------
665    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
666        means that a class such as [\s] counted as "explicit reference to CR or
667        LF". That isn't really right - the whole point of the change was to try to
668        help when there was an actual mention of one of the two characters. So now
669        the change happens only if \r or \n (or a literal CR or LF) character is
670        encountered.
672    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
673        of both had grown to the point where there were only 3 bits left.
674        Fortunately, there was spare space in the data structure, and so I have
675        moved the internal flags into a new 16-bit field to free up more option
676        bits.
678    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
679        but did not set the internal JCHANGED flag - either of these is enough to
680        control the way the "get" function works - but the PCRE_INFO_JCHANGED
681        facility is supposed to tell if (?J) was ever used, so now (?J) at the
682        start sets both bits.
684    4.  Added options (at build time, compile time, exec time) to change \R from
685        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
687    5.  doc/pcresyntax.html was missing from the distribution.
689    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
690        compatibility, even though it is no longer used.
692    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
693        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
694        windows.h file is present (where different names are used). [This was
695        reversed later after testing - see 16 below.]
697    8.  Changed all #include <config.h> to #include "config.h". There were also
698        some further <pcre.h> cases that I changed to "pcre.h".
700    9.  When pcregrep was used with the --colour option, it missed the line ending
701        sequence off the lines that it output.
703    10. It was pointed out to me that arrays of string pointers cause lots of
704        relocations when a shared library is dynamically loaded. A technique of
705        using a single long string with a table of offsets can drastically reduce
706        these. I have refactored PCRE in four places to do this. The result is
707        dramatic:
709          Originally:                          290
710          After changing UCP table:            187
711          After changing error message table:   43
712          After changing table of "verbs"       36
713          After changing table of Posix names   22
715        Thanks to the folks working on Gregex for glib for this insight.
717    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
718        unicode-properties was also set.
720    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
722    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
723        checked only for CRLF.
725    14. Added casts to pcretest.c to avoid compiler warnings.
727    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
729    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
730        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
731        entirely. This removes changes made in 7 above.
733    17. The CMake files have been updated, and there is now more information about
734        building with CMake in the NON-UNIX-USE document.
737    Version 7.3 28-Aug-07
738    ---------------------
740     1. In the rejigging of the build system that eventually resulted in 7.1, the
741        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
742        brackets there is not right, since it causes compilers to look for an
743        installed pcre.h, not the version that is in the source that is being
744        compiled (which of course may be different). I have changed it back to:
746          #include "pcre.h"
748        I have a vague recollection that the change was concerned with compiling in
749        different directories, but in the new build system, that is taken care of
750        by the VPATH setting the Makefile.
752     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
753        when the subject happened to end in the byte 0x85 (e.g. if the last
754        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
755        characters but of course it shouldn't be taken as a newline when it is part
756        of another character. The bug was that, for an unlimited repeat of . in
757        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
758        characters when looking for a newline.
760     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
762     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
763        in debug output.
765     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
766        long printing in the pcrecpp unittest when running under MinGW.
768     6. ESC_K was left out of the EBCDIC table.
770     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
771        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
772        limit also applies to "virtual nesting" when a pattern is recursive, and in
773        this case 1000 isn't so big. I have been able to remove this limit at the
774        expense of backing off one optimization in certain circumstances. Normally,
775        when pcre_exec() would call its internal match() function recursively and
776        immediately return the result unconditionally, it uses a "tail recursion"
777        feature to save stack. However, when a subpattern that can match an empty
778        string has an unlimited repetition quantifier, it no longer makes this
779        optimization. That gives it a stack frame in which to save the data for
780        checking that an empty string has been matched. Previously this was taken
781        from the 1000-entry workspace that had been reserved. So now there is no
782        explicit limit, but more stack is used.
784     8. Applied Daniel's patches to solve problems with the import/export magic
785        syntax that is required for Windows, and which was going wrong for the
786        pcreposix and pcrecpp parts of the library. These were overlooked when this
787        problem was solved for the main library.
789     9. There were some crude static tests to avoid integer overflow when computing
790        the size of patterns that contain repeated groups with explicit upper
791        limits. As the maximum quantifier is 65535, the maximum group length was
792        set at 30,000 so that the product of these two numbers did not overflow a
793        32-bit integer. However, it turns out that people want to use groups that
794        are longer than 30,000 bytes (though not repeat them that many times).
795        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
796        made it possible to implement the integer overflow checks in a much more
797        dynamic way, which I have now done. The artificial limitation on group
798        length has been removed - we now have only the limit on the total length of
799        the compiled pattern, which depends on the LINK_SIZE setting.
801    10. Fixed a bug in the documentation for get/copy named substring when
802        duplicate names are permitted. If none of the named substrings are set, the
803        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
804        empty string.
806    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
807        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
808        because the ] is interpreted as the first data character and the
809        terminating ] is not found. PCRE has been made compatible with Perl in this
810        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
811        cause memory overwriting.
813    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
814        string has been matched (to stop an infinite loop). It was not recognizing
815        a conditional subpattern that could match an empty string if that
816        subpattern was within another subpattern. For example, it looped when
817        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
818        condition was not nested. This bug has been fixed.
820    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
821        past the start of the subject in the presence of bytes with the top bit
822        set, for example "\x8aBCD".
824    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
825        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
827    14. Optimized (?!) to (*FAIL).
829    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
830        This restricts code points to be within the range 0 to 0x10FFFF, excluding
831        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
832        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
833        does: it's just the validity check that is more restrictive.
835    16. Inserted checks for integer overflows during escape sequence (backslash)
836        processing, and also fixed erroneous offset values for syntax errors during
837        backslash processing.
839    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
840        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
842    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
843        caused an overrun.
845    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
846        something other than just ASCII characters) inside a group that had an
847        unlimited repeat caused a loop at compile time (while checking to see
848        whether the group could match an empty string).
850    20. Debugging a pattern containing \p or \P could cause a crash. For example,
851        [\P{Any}] did so. (Error in the code for printing property names.)
853    21. An orphan \E inside a character class could cause a crash.
855    22. A repeated capturing bracket such as (A)? could cause a wild memory
856        reference during compilation.
858    23. There are several functions in pcre_compile() that scan along a compiled
859        expression for various reasons (e.g. to see if it's fixed length for look
860        behind). There were bugs in these functions when a repeated \p or \P was
861        present in the pattern. These operators have additional parameters compared
862        with \d, etc, and these were not being taken into account when moving along
863        the compiled data. Specifically:
865        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
866            length.
868        (b) An item such as \pL+ within a repeated group could cause crashes or
869            loops.
871        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
872            "reference to non-existent subpattern" error.
874        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
876    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
877        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
879    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
881    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
882        character were causing crashes (broken optimization).
884    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
885        \p or \P) caused a compile-time loop.
887    28. More problems have arisen in unanchored patterns when CRLF is a valid line
888        break. For example, the unstudied pattern [\r\n]A does not match the string
889        "\r\nA" because change 7.0/46 below moves the current point on by two
890        characters after failing to match at the start. However, the pattern \nA
891        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
892        the same is true. There doesn't seem any very clean way out of this, but
893        what I have chosen to do makes the common cases work: PCRE now takes note
894        of whether there can be an explicit match for \r or \n anywhere in the
895        pattern, and if so, 7.0/46 no longer applies. As part of this change,
896        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
897        pattern has explicit CR or LF references.
899    29. Added (*CR) etc for changing newline setting at start of pattern.
902    Version 7.2 19-Jun-07
903    ---------------------
905     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
906        which is apparently normally available under Windows.
908     2. Re-jig the pcregrep tests with different newline settings in an attempt
909        to make them independent of the local environment's newline setting.
911     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
913     4. Some of the "internals" tests were previously cut out when the link size
914        was not 2, because the output contained actual offsets. The recent new
915        "Z" feature of pcretest means that these can be cut out, making the tests
916        usable with all link sizes.
918     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
919        stack recursion. This gives a massive performance boost under BSD, but just
920        a small improvement under Linux. However, it saves one field in the frame
921        in all cases.
923     6. Added more features from the forthcoming Perl 5.10:
925        (a) (?-n) (where n is a string of digits) is a relative subroutine or
926            recursion call. It refers to the nth most recently opened parentheses.
928        (b) (?+n) is also a relative subroutine call; it refers to the nth next
929            to be opened parentheses.
931        (c) Conditions that refer to capturing parentheses can be specified
932            relatively, for example, (?(-2)... or (?(+3)...
934        (d) \K resets the start of the current match so that everything before
935            is not part of it.
937        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
939        (f) \g{name} is another synonym - part of Perl 5.10's unification of
940            reference syntax.
942        (g) (?| introduces a group in which the numbering of parentheses in each
943            alternative starts with the same number.
945        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
947     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
950     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
951        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
952        for detecting groups that can match an empty string.
954     9. A pattern with a very large number of alternatives (more than several
955        hundred) was running out of internal workspace during the pre-compile
956        phase, where pcre_compile() figures out how much memory will be needed. A
957        bit of new cunning has reduced the workspace needed for groups with
958        alternatives. The 1000-alternative test pattern now uses 12 bytes of
959        workspace instead of running out of the 4096 that are available.
961    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
963    11. Applied patch from Google to remove an optimization that didn't quite work.
964        The report of the bug said:
966          pcrecpp::RE("a*").FullMatch("aaa") matches, while
967          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
968          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
970    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
971        it matched the wrong number of bytes.
974    Version 7.1 24-Apr-07
975    ---------------------
977     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
978        that is more "standard", making use of automake and other Autotools. There
979        is some re-arrangement of the files and adjustment of comments consequent
980        on this.
982     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
983        for recursive directory scanning broke on some systems because the files
984        are not scanned in any specific order and on different systems the order
985        was different. A call to "sort" has been inserted into RunGrepTest for the
986        approprate test as a short-term fix. In the longer term there may be an
987        alternative.
989     3. I had an email from Eric Raymond about problems translating some of PCRE's
990        man pages to HTML (despite the fact that I distribute HTML pages, some
991        people do their own conversions for various reasons). The problems
992        concerned the use of low-level troff macros .br and .in. I have therefore
993        removed all such uses from the man pages (some were redundant, some could
994        be replaced by .nf/.fi pairs). The 132html script that I use to generate
995        HTML has been updated to handle .nf/.fi and to complain if it encounters
996        .br or .in.
998     4. Updated comments in configure.ac that get placed in config.h.in and also
999        arranged for config.h to be included in the distribution, with the name
1000        config.h.generic, for the benefit of those who have to compile without
1001        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1003     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1004        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1005        makevp.bat for the current PCRE, using the additional files
1006        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1008     6. A Windows user reported a minor discrepancy with test 2, which turned out
1009        to be caused by a trailing space on an input line that had got lost in his
1010        copy. The trailing space was an accident, so I've just removed it.
1012     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1013        that is needed.
1015     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1016        as "const" (a) because they are and (b) because it helps the PHP
1017        maintainers who have recently made a script to detect big data structures
1018        in the php code that should be moved to the .rodata section. I remembered
1019        to update Builducptable as well, so it won't revert if ucptable.h is ever
1020        re-created.
1022     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1023        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1024        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1025        support is not required. This saves 1.5-2K of code, which is important in
1026        some applications.
1028        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1029        so as not to refer to the tables, even though these functions will never be
1030        called when UTF-8 support is disabled. Otherwise there are problems with a
1031        shared library.
1033    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1035        (a) It was defining its arguments as char * instead of void *.
1037        (b) It was assuming that all moves were upwards in memory; this was true
1038            a long time ago when I wrote it, but is no longer the case.
1040        The emulated memove() is provided for those environments that have neither
1041        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1042        is clearly not the case, as these two bugs were recently reported.
1044    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1045        and Detrail to create the HTML documentation, the .txt form of the man
1046        pages, and it removes trailing spaces from listed files. It also creates
1047        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1048        case, it wraps all the #defines with #ifndefs. This script should be run
1049        before "make dist".
1051    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1052        with Unicode property support.
1054        (a) For a maximizing quantifier, if the two different cases of the
1055            character were of different lengths in their UTF-8 codings (there are
1056            some cases like this - I found 11), and the matching function had to
1057            back up over a mixture of the two cases, it incorrectly assumed they
1058            were both the same length.
1060        (b) When PCRE was configured to use the heap rather than the stack for
1061            recursion during matching, it was not correctly preserving the data for
1062            the other case of a UTF-8 character when checking ahead for a match
1063            while processing a minimizing repeat. If the check also involved
1064            matching a wide character, but failed, corruption could cause an
1065            erroneous result when trying to check for a repeat of the original
1066            character.
1068    13. Some tidying changes to the testing mechanism:
1070        (a) The RunTest script now detects the internal link size and whether there
1071            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1072            values substituted by "configure". (The RunGrepTest script already did
1073            this for UTF-8.) The configure.ac script no longer substitutes the
1074            relevant variables.
1076        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1077            with length and offset values. This means that the output is different
1078            for different internal link sizes. Test 2 is skipped for link sizes
1079            other than 2 because of this, bypassing the problem. Unfortunately,
1080            there was also a test in test 3 (the locale tests) that used /B and
1081            failed for link sizes other than 2. Rather than cut the whole test out,
1082            I have added a new /Z option to pcretest that replaces the length and
1083            offset values with spaces. This is now used to make test 3 independent
1084            of link size. (Test 2 will be tidied up later.)
1086    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1087        segmentation fault instead of returning the appropriate error message.
1089    15. In multiline mode when the newline sequence was set to "any", the pattern
1090        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1091        This doesn't seem right; it now treats the CRLF combination as the line
1092        ending, and so does not match in that case. It's only a pattern such as ^$
1093        that would hit this one: something like ^ABC$ would have failed after \r
1094        and then tried again after \r\n.
1096    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1097        in an attempt to make files that differ only in their line terminators
1098        compare equal. This works on Linux.
1100    17. Under certain error circumstances pcregrep might try to free random memory
1101        as it exited. This is now fixed, thanks to valgrind.
1103    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1104        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1105        was because its rules for how to advance for /g after matching an empty
1106        string at the end of a line did not allow for this case. They now check for
1107        it specially.
1109    20. pcretest is supposed to handle patterns and data of any length, by
1110        extending its buffers when necessary. It was getting this wrong when the
1111        buffer for a data line had to be extended.
1113    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1114        CRLF as a newline sequence.
1116    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1117        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1118        I have nevertheless tidied it up.
1120    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1122    24. Added a man page for pcre-config.
1125    Version 7.0 19-Dec-06
1126    ---------------------
1128     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1129        moving to gcc 4.1.1.
1131     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1132        sys/time.h, which is documented as needed for this function. It doesn't
1133        seem to matter on Linux, but it showed up on some releases of OS X.
1135     3. It seems that there are systems where bytes whose values are greater than
1136        127 match isprint() in the "C" locale. The "C" locale should be the
1137        default when a C program starts up. In most systems, only ASCII printing
1138        characters match isprint(). This difference caused the output from pcretest
1139        to vary, making some of the tests fail. I have changed pcretest so that:
1141        (a) When it is outputting text in the compiled version of a pattern, bytes
1142            other than 32-126 are always shown as hex escapes.
1144        (b) When it is outputting text that is a matched part of a subject string,
1145            it does the same, unless a different locale has been set for the match
1146            (using the /L modifier). In this case, it uses isprint() to decide.
1148     4. Fixed a major bug that caused incorrect computation of the amount of memory
1149        required for a compiled pattern when options that changed within the
1150        pattern affected the logic of the preliminary scan that determines the
1151        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1152        that the computed length was too small. The symptoms of this bug were
1153        either the PCRE error "internal error: code overflow" from pcre_compile(),
1154        or a glibc crash with a message such as "pcretest: free(): invalid next
1155        size (fast)". Examples of patterns that provoked this bug (shown in
1156        pcretest format) are:
1158          /(?-x: )/x
1159          /(?x)(?-x: \s*#\s*)/
1160          /((?i)[\x{c0}])/8
1161          /(?i:[\x{c0}])/8
1163        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1164        is now done differently.
1166     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1167        wrapper classes; (b) implement a new function in the C++ scanner that is
1168        more efficient than the old way of doing things because it avoids levels of
1169        recursion in the regex matching; (c) add a paragraph to the documentation
1170        for the FullMatch() function.
1172     6. The escape sequence \n was being treated as whatever was defined as
1173        "newline". Not only was this contrary to the documentation, which states
1174        that \n is character 10 (hex 0A), but it also went horribly wrong when
1175        "newline" was defined as CRLF. This has been fixed.
1177     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1178        was being set to -1 for the "end of line" case (supposedly a value that no
1179        character can have). Though this value is never used (the check for end of
1180        line is "zero bytes in current character"), it caused compiler complaints.
1181        I've changed it to 0xffffffff.
1183     8. In pcre_version.c, the version string was being built by a sequence of
1184        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1185        string (as it is for production releases) called a macro with an empty
1186        argument. The C standard says the result of this is undefined. The gcc
1187        compiler treats it as an empty string (which was what was wanted) but it is
1188        reported that Visual C gives an error. The source has been hacked around to
1189        avoid this problem.
1191     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1192        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1193        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1194        of them did).
1196    10. Originally, pcretest opened its input and output without "b"; then I was
1197        told that "b" was needed in some environments, so it was added for release
1198        5.0 to both the input and output. (It makes no difference on Unix-like
1199        systems.) Later I was told that it is wrong for the input on Windows. I've
1200        now abstracted the modes into two macros, to make it easier to fiddle with
1201        them, and removed "b" from the input mode under Windows.
1203    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1205    12. Added -help and --help to pcretest as an official way of being reminded
1206        of the options.
1208    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1209        and pcrecpp.cc because they annoy compilers at high warning levels.
1211    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1213    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1214        scripts are not C programs :-) and which was not noticed because it works
1215        on Linux.
1217    16. pcretest is supposed to handle any length of pattern and data line (as one
1218        line or as a continued sequence of lines) by extending its input buffer if
1219        necessary. This feature was broken for very long pattern lines, leading to
1220        a string of junk being passed to pcre_compile() if the pattern was longer
1221        than about 50K.
1223    17. I have done a major re-factoring of the way pcre_compile() computes the
1224        amount of memory needed for a compiled pattern. Previously, there was code
1225        that made a preliminary scan of the pattern in order to do this. That was
1226        OK when PCRE was new, but as the facilities have expanded, it has become
1227        harder and harder to keep it in step with the real compile phase, and there
1228        have been a number of bugs (see for example, 4 above). I have now found a
1229        cunning way of running the real compile function in a "fake" mode that
1230        enables it to compute how much memory it would need, while actually only
1231        ever using a few hundred bytes of working memory and without too many
1232        tests of the mode. This should make future maintenance and development
1233        easier. A side effect of this work is that the limit of 200 on the nesting
1234        depth of parentheses has been removed (though this was never a serious
1235        limitation, I suspect). However, there is a downside: pcre_compile() now
1236        runs more slowly than before (30% or more, depending on the pattern). I
1237        hope this isn't a big issue. There is no effect on runtime performance.
1239    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1240        newline (only possible for the last line of a file) and it was a
1241        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1243    19. Added additional timing features to pcretest. (1) The -tm option now times
1244        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1245        separate command line item, by a number that specifies the number of
1246        repeats to use when timing. The default is 50000; this gives better
1247        precision, but takes uncomfortably long for very large patterns.
1249    20. Extended pcre_study() to be more clever in cases where a branch of a
1250        subpattern has no definite first character. For example, (a*|b*)[cd] would
1251        previously give no result from pcre_study(). Now it recognizes that the
1252        first character must be a, b, c, or d.
1254    21. There was an incorrect error "recursive call could loop indefinitely" if
1255        a subpattern (or the entire pattern) that was being tested for matching an
1256        empty string contained only one non-empty item after a nested subpattern.
1257        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1258        incorrectly, because the \d was being skipped in the check.
1260    22. The pcretest program now has a new pattern option /B and a command line
1261        option -b, which is equivalent to adding /B to every pattern. This causes
1262        it to show the compiled bytecode, without the additional information that
1263        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1264        is the same as /B/I).
1266    23. A new optimization is now able automatically to treat some sequences such
1267        as a*b as a*+b. More specifically, if something simple (such as a character
1268        or a simple class like \d) has an unlimited quantifier, and is followed by
1269        something that cannot possibly match the quantified thing, the quantifier
1270        is automatically "possessified".
1272    24. A recursive reference to a subpattern whose number was greater than 39
1273        went wrong under certain circumstances in UTF-8 mode. This bug could also
1274        have affected the operation of pcre_study().
1276    25. Realized that a little bit of performance could be had by replacing
1277        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1279    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1281    27. Possessive quantifiers such as a++ were previously implemented by turning
1282        them into atomic groups such as ($>a+). Now they have their own opcodes,
1283        which improves performance. This includes the automatically created ones
1284        from 23 above.
1286    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1287        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1288        the first matched character to be a colon. This applied both to named and
1289        numbered groups.
1291    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1293    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1294        building PCRE on Windows easier, so I have included it in the distribution.
1296    31. There is now a check in pcretest against a ridiculously large number being
1297        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1298        loop, the loop is abandoned.
1300    32. Forward references to subpatterns in conditions such as (?(2)...) where
1301        subpattern 2 is defined later cause pcre_compile() to search forwards in
1302        the pattern for the relevant set of parentheses. This search went wrong
1303        when there were unescaped parentheses in a character class, parentheses
1304        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1306    33. "Subroutine" calls and backreferences were previously restricted to
1307        referencing subpatterns earlier in the regex. This restriction has now
1308        been removed.
1310    34. Added a number of extra features that are going to be in Perl 5.10. On the
1311        whole, these are just syntactic alternatives for features that PCRE had
1312        previously implemented using the Python syntax or my own invention. The
1313        other formats are all retained for compatibility.
1315        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1316            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1317            also .NET compatible.
1319        (b) A recursion or subroutine call to a named group can now be defined as
1320            (?&name) as well as (?P>name).
1322        (c) A backreference to a named group can now be defined as \k<name> or
1323            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1324            5.10, are also .NET compatible.
1326        (d) A conditional reference to a named group can now use the syntax
1327            (?(<name>) or (?('name') as well as (?(name).
1329        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1330            groups (named and numbered) that are never evaluated inline, but can be
1331            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1332            is always false. There may be only one alternative in such a group.
1334        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1335            as the simple (?(R). The condition is true only if the most recent
1336            recursion is that of the given number or name. It does not search out
1337            through the entire recursion stack.
1339        (g) The escape \gN or \g{N} has been added, where N is a positive or
1340            negative number, specifying an absolute or relative reference.
1342    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1343        some "unreachable code" warnings.
1345    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1346        things, this adds five new scripts.
1348    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1349        There were also incompatibilities regarding the handling of \Q..\E inside
1350        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1351        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1353    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1354        matches an empty string, and forcibly breaks the loop. There were bugs in
1355        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1356        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1357        separate and independent bugs (that affected different cases) have been
1358        fixed.
1360    39. Refactored the code to abolish the use of different opcodes for small
1361        capturing bracket numbers. This is a tidy that I avoided doing when I
1362        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1363        The new approach is not only tidier, it makes it possible to reduce the
1364        memory needed to fix the previous bug (38).
1366    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1367        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1368        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1369        mode.
1371    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1372        report.
1374    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1375        copy construction and assignment in the C++ wrapper.
1377    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1378        couple of bugs that could have given wrong results in the "--newline=crlf"
1379        case.
1381    44. Added a number of casts and did some reorganization of signed/unsigned int
1382        variables following suggestions from Dair Grant. Also renamed the variable
1383        "this" as "item" because it is a C++ keyword.
1385    45. Arranged for dftables to add
1387          #include "pcre_internal.h"
1389        to pcre_chartables.c because without it, gcc 4.x may remove the array
1390        definition from the final binary if PCRE is built into a static library and
1391        dead code stripping is activated.
1393    46. For an unanchored pattern, if a match attempt fails at the start of a
1394        newline sequence, and the newline setting is CRLF or ANY, and the next two
1395        characters are CRLF, advance by two characters instead of one.
1398    Version 6.7 04-Jul-06
1399    ---------------------
1401     1. In order to handle tests when input lines are enormously long, pcretest has
1402        been re-factored so that it automatically extends its buffers when
1403        necessary. The code is crude, but this _is_ just a test program. The
1404        default size has been increased from 32K to 50K.
1406     2. The code in pcre_study() was using the value of the re argument before
1407        testing it for NULL. (Of course, in any sensible call of the function, it
1408        won't be NULL.)
1410     3. The memmove() emulation function in pcre_internal.h, which is used on
1411        systems that lack both memmove() and bcopy() - that is, hardly ever -
1412        was missing a "static" storage class specifier.
1414     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1415        containing an extended class (one that cannot be represented by a bitmap
1416        because it contains high-valued characters or Unicode property items, e.g.
1417        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1418        pattern, but PCRE should not loop if you do not (it no longer does).
1419        [Detail: two cases were found: (a) a repeated subpattern containing an
1420        extended class; (b) a recursive reference to a subpattern that followed a
1421        previous extended class. It wasn't skipping over the extended class
1422        correctly when UTF-8 mode was not set.]
1424     5. A negated single-character class was not being recognized as fixed-length
1425        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1426        compile error "lookbehind assertion is not fixed length".
1428     6. The RunPerlTest auxiliary script was showing an unexpected difference
1429        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1430        write a Perl script that can interpret lines of an input file either as
1431        byte characters or as UTF-8, which is what "perltest" was being required to
1432        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1433        can't do is switch easily at run time between having the "use utf8;" pragma
1434        or not. In the end, I fudged it by using the RunPerlTest script to insert
1435        "use utf8;" explicitly for the UTF-8 tests.
1437     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1438        the end of the subject string, contrary to the documentation and to what
1439        Perl does. This was true of both matching functions. Now it matches only at
1440        the start of the subject and immediately after *internal* newlines.
1442     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1443        a pointer to an int instead of a pointer to an unsigned long int. This
1444        caused problems on 64-bit systems.
1446     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1447        instance of the 'standard' template library not being so standard".
1449    10. There was no check on the number of named subpatterns nor the maximum
1450        length of a subpattern name. The product of these values is used to compute
1451        the size of the memory block for a compiled pattern. By supplying a very
1452        long subpattern name and a large number of named subpatterns, the size
1453        computation could be caused to overflow. This is now prevented by limiting
1454        the length of names to 32 characters, and the number of named subpatterns
1455        to 10,000.
1457    11. Subpatterns that are repeated with specific counts have to be replicated in
1458        the compiled pattern. The size of memory for this was computed from the
1459        length of the subpattern and the repeat count. The latter is limited to
1460        65535, but there was no limit on the former, meaning that integer overflow
1461        could in principle occur. The compiled length of a repeated subpattern is
1462        now limited to 30,000 bytes in order to prevent this.
1464    12. Added the optional facility to have named substrings with the same name.
1466    13. Added the ability to use a named substring as a condition, using the
1467        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1468        are numbers (not recommended). Forward references are permitted.
1470    14. Added forward references in named backreferences (if you see what I mean).
1472    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1473        pattern could run off the end of the subject. For example, the pattern
1474        "(?s)(.{1,5})"8 did this with the subject "ab".
1476    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1477        PCRE_CASELESS was set when matching characters that were quantified with ?
1478        or *.
1480    17. A character class other than a single negated character that had a minimum
1481        but no maximum quantifier - for example [ab]{6,} - was not handled
1482        correctly by pce_dfa_exec(). It would match only one character.
1484    18. A valid (though odd) pattern that looked like a POSIX character
1485        class but used an invalid character after [ (for example [[,abc,]]) caused
1486        pcre_compile() to give the error "Failed: internal error: code overflow" or
1487        in some cases to crash with a glibc free() error. This could even happen if
1488        the pattern terminated after [[ but there just happened to be a sequence of
1489        letters, a binary zero, and a closing ] in the memory that followed.
1491    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1492        over the years. Originally (before any Unicode support), just the bottom 8
1493        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1494        output from "man perlunicode" includes this:
1496          The regular expression compiler produces polymorphic opcodes.  That
1497          is, the pattern adapts to the data and automatically switches to
1498          the Unicode character scheme when presented with Unicode data--or
1499          instead uses a traditional byte scheme when presented with byte
1500          data.
1502        Sadly, a wide octal escape does not cause a switch, and in a string with
1503        no other multibyte characters, these octal escapes are treated as before.
1504        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1505        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1506        Unicode string.
1508        I have not perpetrated such confusion in PCRE. Up till now, it took just
1509        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1510        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1511        translate to the appropriate multibyte character.
1513    29. Applied some refactoring to reduce the number of warnings from Microsoft
1514        and Borland compilers. This has included removing the fudge introduced
1515        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1516        a warning about an unused variable.
1518    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1519        characters since release 4.0, because Perl (from release 5.004) does not.
1520        [Or at least, is documented not to: some releases seem to be in conflict
1521        with the documentation.] However, when a pattern was studied with
1522        pcre_study() and all its branches started with \s, PCRE still included VT
1523        as a possible starting character. Of course, this did no harm; it just
1524        caused an unnecessary match attempt.
1526    22. Removed a now-redundant internal flag bit that recorded the fact that case
1527        dependency changed within the pattern. This was once needed for "required
1528        byte" processing, but is no longer used. This recovers a now-scarce options
1529        bit. Also moved the least significant internal flag bit to the most-
1530        significant bit of the word, which was not previously used (hangover from
1531        the days when it was an int rather than a uint) to free up another bit for
1532        the future.
1534    23. Added support for CRLF line endings as well as CR and LF. As well as the
1535        default being selectable at build time, it can now be changed at runtime
1536        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1537        specify that it is scanning data with non-default line endings.
1539    24. Changed the definition of CXXLINK to make it agree with the definition of
1540        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1542    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1543        recursions. This makes a big different to stack usage for some patterns.
1545    26. If a subpattern containing a named recursion or subroutine reference such
1546        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1547        the space required for the compiled pattern went wrong and gave too small a
1548        value. Depending on the environment, this could lead to "Failed: internal
1549        error: code overflow at offset 49" or "glibc detected double free or
1550        corruption" errors.
1552    27. Applied patches from Google (a) to support the new newline modes and (b) to
1553        advance over multibyte UTF-8 characters in GlobalReplace.
1555    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1556        difference for some implementation of PCRE in some Windows version.
1558    29. Added some extra testing facilities to pcretest:
1560        \q<number>   in a data line sets the "match limit" value
1561        \Q<number>   in a data line sets the "match recursion limt" value
1562        -S <number>  sets the stack size, where <number> is in megabytes
1564        The -S option isn't available for Windows.
1567    Version 6.6 06-Feb-06
1568    ---------------------
1570     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1571        in pcreposix.h. I have copied the definition from pcre.h.
1573     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1574        because pcre.h is no longer a built file.
1576     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1577        not normally included in the compiled code.
1580    Version 6.5 01-Feb-06
1581    ---------------------
1583     1. When using the partial match feature with pcre_dfa_exec(), it was not
1584        anchoring the second and subsequent partial matches at the new starting
1585        point. This could lead to incorrect results. For example, with the pattern
1586        /1234/, partially matching against "123" and then "a4" gave a match.
1588     2. Changes to pcregrep:
1590        (a) All non-match returns from pcre_exec() were being treated as failures
1591            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1592            error message is output. Some extra information is given for the
1593            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1594            probably the only errors that are likely to be caused by users (by
1595            specifying a regex that has nested indefinite repeats, for instance).
1596            If there are more than 20 of these errors, pcregrep is abandoned.
1598        (b) A binary zero was treated as data while matching, but terminated the
1599            output line if it was written out. This has been fixed: binary zeroes
1600            are now no different to any other data bytes.
1602        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1603            used to set a locale for matching. The --locale=xxxx long option has
1604            been added (no short equivalent) to specify a locale explicitly on the
1605            pcregrep command, overriding the environment variables.
1607        (d) When -B was used with -n, some line numbers in the output were one less
1608            than they should have been.
1610        (e) Added the -o (--only-matching) option.
1612        (f) If -A or -C was used with -c (count only), some lines of context were
1613            accidentally printed for the final match.
1615        (g) Added the -H (--with-filename) option.
1617        (h) The combination of options -rh failed to suppress file names for files
1618            that were found from directory arguments.
1620        (i) Added the -D (--devices) and -d (--directories) options.
1622        (j) Added the -F (--fixed-strings) option.
1624        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1626        (l) Added the --colo(u)r option.
1628        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1629            is not present by default.
1631     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1632        items such as (?R) or (?1), when the recursion could match a number of
1633        alternatives. If it matched one of the alternatives, but subsequently,
1634        outside the recursion, there was a failure, the code tried to back up into
1635        the recursion. However, because of the way PCRE is implemented, this is not
1636        possible, and the result was an incorrect result from the match.
1638        In order to prevent this happening, the specification of recursion has
1639        been changed so that all such subpatterns are automatically treated as
1640        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1642     4. I had overlooked the fact that, in some locales, there are characters for
1643        which isalpha() is true but neither isupper() nor islower() are true. In
1644        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1645        and ordfeminine) are like this. This affected the treatment of \w and \W
1646        when they appeared in character classes, but not when they appeared outside
1647        a character class. The bit map for "word" characters is now created
1648        separately from the results of isalnum() instead of just taking it from the
1649        upper, lower, and digit maps. (Plus the underscore character, of course.)
1651     5. The above bug also affected the handling of POSIX character classes such as
1652        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1653        permanent tables. Instead, the bit maps for such a class were previously
1654        created as the appropriate unions of the upper, lower, and digit bitmaps.
1655        Now they are created by subtraction from the [[:word:]] class, which has
1656        its own bitmap.
1658     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1659        It is created by subtracting the vertical space characters (\x09, \x0a,
1660        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1661        subtraction was done in the overall bitmap for a character class, meaning
1662        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1663        be recognized. This bug has been fixed.
1665     7. Patches from the folks at Google:
1667          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1668          real life, but is still worth protecting against".
1670          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1671          regular expressions".
1673          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1674          have it.
1676          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1677          "configure" and the latter not, in order to fix a problem somebody had
1678          with compiling the Arg class on HP-UX.
1680          (e) Improve the error-handling of the C++ wrapper a little bit.
1682          (f) New tests for checking recursion limiting.
1684     8. The pcre_memmove() function, which is used only if the environment does not
1685        have a standard memmove() function (and is therefore rarely compiled),
1686        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1687        returning a result (though PCRE never actually uses the result).
1689     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1690        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1691        returned instead of calling malloc() with an overflowing number that would
1692        most likely cause subsequent chaos.
1694    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1696    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1697        with this option is matched, the nmatch and pmatch options of regexec() are
1698        ignored.
1700    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1701        provided in case anyone wants to the the POSIX interface with UTF-8
1702        strings.
1704    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1705        C++ linking (needed for some HP-UX environments).
1707    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1708        (unused parameter) and in the pcre_printint() function (omitted "default"
1709        switch label when the default is to do nothing).
1711    15. Added some code to make it possible, when PCRE is compiled as a C++
1712        library, to replace subject pointers for pcre_exec() with a smart pointer
1713        class, thus making it possible to process discontinuous strings.
1715    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1716        much the same function. They were added by different people who were trying
1717        to make PCRE easy to compile on non-Unix systems. It has been suggested
1718        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1719        for compiling on Windows systems. I have therefore replaced it with
1720        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1721        defaults to "extern" for C or "extern C" for C++, which works fine on
1722        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1723        SCOPE with something explicit in config.h. In addition:
1725        (a) pcreposix.h still had just "extern" instead of either of these macros;
1726            I have replaced it with PCRE_DATA_SCOPE.
1728        (b) Functions such as _pcre_xclass(), which are internal to the library,
1729            but external in the C sense, all had PCRE_EXPORT in their definitions.
1730            This is apparently wrong for the Windows case, so I have removed it.
1731            (It makes no difference on Unix-like systems.)
1733    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1734        of recursive calls to match(). This is different to MATCH_LIMIT because
1735        that limits the total number of calls to match(), not all of which increase
1736        the depth of recursion. Limiting the recursion depth limits the amount of
1737        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1738        when PCRE is compiled, and changed at run time. A patch from Google adds
1739        this functionality to the C++ interface.
1741    18. Changes to the handling of Unicode character properties:
1743        (a) Updated the table to Unicode 4.1.0.
1745        (b) Recognize characters that are not in the table as "Cn" (undefined).
1747        (c) I revised the way the table is implemented to a much improved format
1748            which includes recognition of ranges. It now supports the ranges that
1749            are defined in UnicodeData.txt, and it also amalgamates other
1750            characters into ranges. This has reduced the number of entries in the
1751            table from around 16,000 to around 3,000, thus reducing its size
1752            considerably. I realized I did not need to use a tree structure after
1753            all - a binary chop search is just as efficient. Having reduced the
1754            number of entries, I extended their size from 6 bytes to 8 bytes to
1755            allow for more data.
1757        (d) Added support for Unicode script names via properties such as \p{Han}.
1759    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1760        matching that character.
1762    20. When matching a repeated Unicode property with a minimum greater than zero,
1763        (for example \pL{2,}), PCRE could look past the end of the subject if it
1764        reached it while seeking the minimum number of characters. This could
1765        happen only if some of the characters were more than one byte long, because
1766        there is a check for at least the minimum number of bytes.
1768    21. Refactored the implementation of \p and \P so as to be more general, to
1769        allow for more different types of property in future. This has changed the
1770        compiled form incompatibly. Anybody with saved compiled patterns that use
1771        \p or \P will have to recompile them.
1773    22. Added "Any" and "L&" to the supported property types.
1775    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1776        but give a compile time error if the value is greater than 0xff.
1778    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1779        accidentally not being installed or uninstalled.
1781    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1782        made were to insert the current release number. This seemed silly, because
1783        it made things harder for people building PCRE on systems that don't run
1784        "configure". I have turned pcre.h into a distributed file, no longer built
1785        by "configure", with the version identification directly included. There is
1786        no longer a pcre.h.in file.
1788        However, this change necessitated a change to the pcre-config script as
1789        well. It is built from pcre-config.in, and one of the substitutions was the
1790        release number. I have updated configure.ac so that ./configure now finds
1791        the release number by grepping pcre.h.
1793    26. Added the ability to run the tests under valgrind.
1796    Version 6.4 05-Sep-05
1797    ---------------------
1799     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1800        "--" to be printed when multiple files were scanned, even when none of the
1801        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1802        consider it to be a bug, and have restored the previous behaviour.
1804     2. A couple of code tidies to get rid of compiler warnings.
1806     3. The pcretest program used to cheat by referring to symbols in the library
1807        whose names begin with _pcre_. These are internal symbols that are not
1808        really supposed to be visible externally, and in some environments it is
1809        possible to suppress them. The cheating is now confined to including
1810        certain files from the library's source, which is a bit cleaner.
1812     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1813        file's purpose clearer.
1815     5. Reorganized pcre_ucp_findchar().
1818    Version 6.3 15-Aug-05
1819    ---------------------
1821     1. The file libpcre.pc.in did not have general read permission in the tarball.
1823     2. There were some problems when building without C++ support:
1825        (a) If C++ support was not built, "make install" and "make test" still
1826            tried to test it.
1828        (b) There were problems when the value of CXX was explicitly set. Some
1829            changes have been made to try to fix these, and ...
1831        (c) --disable-cpp can now be used to explicitly disable C++ support.
1833        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1834            backslash in a target when C++ was disabled. This confuses some
1835            versions of "make", apparently. Using an intermediate variable solves
1836            this. (Same for CPP_LOBJ.)
1838     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1839        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1840        necessary on certain architectures.
1842     4. Added a setting of -export-symbols-regex to the link command to remove
1843        those symbols that are exported in the C sense, but actually are local
1844        within the library, and not documented. Their names all begin with
1845        "_pcre_". This is not a perfect job, because (a) we have to except some
1846        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1847        available (and never for static libraries). I have made a note to try to
1848        find a way round (a) in the future.
1851    Version 6.2 01-Aug-05
1852    ---------------------
1854     1. There was no test for integer overflow of quantifier values. A construction
1855        such as {1111111111111111} would give undefined results. What is worse, if
1856        a minimum quantifier for a parenthesized subpattern overflowed and became
1857        negative, the calculation of the memory size went wrong. This could have
1858        led to memory overwriting.
1860     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1862     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1863        operating environments where this matters.
1865     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1866        PCRE options from within the C++ wrapper.
1868     5. Named capturing subpatterns were not being correctly counted when a pattern
1869        was compiled. This caused two problems: (a) If there were more than 100
1870        such subpatterns, the calculation of the memory needed for the whole
1871        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1872        back references of the form \12, where the number was greater than 9, were
1873        not recognized as back references, even though there were sufficient
1874        previous subpatterns.
1876     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1877        versions of gcc, e.g. 2.95.4.
1880    Version 6.1 21-Jun-05
1881    ---------------------
1883     1. There was one reference to the variable "posix" in pcretest.c that was not
1884        surrounded by "#if !defined NOPOSIX".
1886     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1887        the cross-check on the old pcre_info() function, for the benefit of the
1888        cut-down version of PCRE that is currently imported into Exim.
1890     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1891        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1892        patterns that start (?i) but I don't think that matters. The use of (?i) is
1893        just an example; this all applies to the other options as well.
1895     4. Since libtool seems to echo the compile commands it is issuing, the output
1896        from "make" can be reduced a bit by putting "@" in front of each libtool
1897        compile command.
1899     5. Patch from the folks at Google for configure.in to be a bit more thorough
1900        in checking for a suitable C++ installation before trying to compile the
1901        C++ stuff. This should fix a reported problem when a compiler was present,
1902        but no suitable headers.
1904     6. The man pages all had just "PCRE" as their title. I have changed them to
1905        be the relevant file name. I have also arranged that these names are
1906        retained in the file doc/pcre.txt, which is a concatenation in text format
1907        of all the man pages except the little individual ones for each function.
1909     7. The NON-UNIX-USE file had not been updated for the different set of source
1910        files that come with release 6. I also added a few comments about the C++
1911        wrapper.
1914    Version 6.0 07-Jun-05
1915    ---------------------
1917     1. Some minor internal re-organization to help with my DFA experiments.
1919     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1920        didn't matter for the library itself when fully configured, but did matter
1921        when compiling without UCP support, or within Exim, where the ucp files are
1922        not imported.
1924     3. Refactoring of the library code to split up the various functions into
1925        different source modules. The addition of the new DFA matching code (see
1926        below) to a single monolithic source would have made it really too
1927        unwieldy, quite apart from causing all the code to be include in a
1928        statically linked application, when only some functions are used. This is
1929        relevant even without the DFA addition now that patterns can be compiled in
1930        one application and matched in another.
1932        The downside of splitting up is that there have to be some external
1933        functions and data tables that are used internally in different modules of
1934        the library but which are not part of the API. These have all had their
1935        names changed to start with "_pcre_" so that they are unlikely to clash
1936        with other external names.
1938     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1939        a different (DFA) algorithm. Although it is slower than the original
1940        function, it does have some advantages for certain types of matching
1941        problem.
1943     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1944        including restarting after a partial match.
1946     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1947        defined when compiling for Windows was sent to me. I have put it into the
1948        code, though I have no means of testing or verifying it.
1950     7. Added the pcre_refcount() auxiliary function.
1952     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1953        match before or at the first newline in the subject string. In pcretest,
1954        the /f option on a pattern can be used to set this.
1956     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1957        would behave wrongly. This has been present in PCRE since release 4.0.
1959    10. A number of changes to the pcregrep command:
1961        (a) Refactored how -x works; insert ^(...)$ instead of setting
1962            PCRE_ANCHORED and checking the length, in preparation for adding
1963            something similar for -w.
1965        (b) Added the -w (match as a word) option.
1967        (c) Refactored the way lines are read and buffered so as to have more
1968            than one at a time available.
1970        (d) Implemented a pcregrep test script.
1972        (e) Added the -M (multiline match) option. This allows patterns to match
1973            over several lines of the subject. The buffering ensures that at least
1974            8K, or the rest of the document (whichever is the shorter) is available
1975            for matching (and similarly the previous 8K for lookbehind assertions).
1977        (f) Changed the --help output so that it now says
1979              -w, --word-regex(p)
1981            instead of two lines, one with "regex" and the other with "regexp"
1982            because that confused at least one person since the short forms are the
1983            same. (This required a bit of code, as the output is generated
1984            automatically from a table. It wasn't just a text change.)
1986        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1987            option but starts with a hyphen. Could be a pattern or a path name
1988            starting with a hyphen, for instance.
1990        (h) "-" can be given as a file name to represent stdin.
1992        (i) When file names are being printed, "(standard input)" is used for
1993            the standard input, for compatibility with GNU grep. Previously
1994            "<stdin>" was used.
1996        (j) The option --label=xxx can be used to supply a name to be used for
1997            stdin when file names are being printed. There is no short form.
1999        (k) Re-factored the options decoding logic because we are going to add
2000            two more options that take data. Such options can now be given in four
2001            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2003        (l) Added the -A, -B, and -C options for requesting that lines of context
2004            around matches be printed.
2006        (m) Added the -L option to print the names of files that do not contain
2007            any matching lines, that is, the complement of -l.
2009        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2010            continue to scan other files.
2012        (o) The -s option was incorrectly implemented. For compatibility with other
2013            greps, it now suppresses the error message for a non-existent or non-
2014            accessible file (but not the return code). There is a new option called
2015            -q that suppresses the output of matching lines, which was what -s was
2016            previously doing.
2018        (p) Added --include and --exclude options to specify files for inclusion
2019            and exclusion when recursing.
2021    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2022        Hopefully, it now does.
2024    12. Missing cast in pcre_study().
2026    13. Added an "uninstall" target to the makefile.
2028    14. Replaced "extern" in the function prototypes in Makefile.in with
2029        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2030        world, but is set differently for Windows.
2032    15. Added a second compiling function called pcre_compile2(). The only
2033        difference is that it has an extra argument, which is a pointer to an
2034        integer error code. When there is a compile-time failure, this is set
2035        non-zero, in addition to the error test pointer being set to point to an
2036        error message. The new argument may be NULL if no error number is required
2037        (but then you may as well call pcre_compile(), which is now just a
2038        wrapper). This facility is provided because some applications need a
2039        numeric error indication, but it has also enabled me to tidy up the way
2040        compile-time errors are handled in the POSIX wrapper.
2042    16. Added VPATH=.libs to the makefile; this should help when building with one
2043        prefix path and installing with another. (Or so I'm told by someone who
2044        knows more about this stuff than I do.)
2046    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2047        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2048        match everything, including newlines. This is not POSIX-compatible, but
2049        somebody wanted the feature. From pcretest it can be activated by using
2050        both the P and the s flags.
2052    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2054    19. libpcre.pc was being incorrectly installed as executable.
2056    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2057        it now also looks for '\r' so that it will work unmodified on Windows.
2059    21. Added Google's contributed C++ wrapper to the distribution.
2061    22. Added some untidy missing memory free() calls in pcretest, to keep
2062        Electric Fence happy when testing.
2066    Version 5.0 13-Sep-04
2067    ---------------------
2069     1. Internal change: literal characters are no longer packed up into items
2070        containing multiple characters in a single byte-string. Each character
2071        is now matched using a separate opcode. However, there may be more than one
2072        byte in the character in UTF-8 mode.
2074     2. The pcre_callout_block structure has two new fields: pattern_position and
2075        next_item_length. These contain the offset in the pattern to the next match
2076        item, and its length, respectively.
2078     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2079        insertion of callouts before each pattern item. Added the /C option to
2080        pcretest to make use of this.
2082     4. On the advice of a Windows user, the lines
2084          #if defined(_WIN32) || defined(WIN32)
2085          _setmode( _fileno( stdout ), 0x8000 );
2086          #endif  /* defined(_WIN32) || defined(WIN32) */
2088        have been added to the source of pcretest. This apparently does useful
2089        magic in relation to line terminators.
2091     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2092        for the benefit of those environments where the "b" makes a difference.
2094     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2095        to know about it. I have put a hack into configure.in that adds in code
2096        to set GCC=yes if CC=icc. This seems to end up at a point in the
2097        generated configure script that is early enough to affect the setting of
2098        compiler options, which is what is needed, but I have no means of testing
2099        whether it really works. (The user who reported this had patched the
2100        generated configure script, which of course I cannot do.)
2102        LATER: After change 22 below (new libtool files), the configure script
2103        seems to know about icc (and also ecc). Therefore, I have commented out
2104        this hack in configure.in.
2106     7. Added support for pkg-config (2 patches were sent in).
2108     8. Negated POSIX character classes that used a combination of internal tables
2109        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2110        [[:^ascii]]. Typically, they would match almost any characters. The other
2111        POSIX classes were not broken in this way.
2113     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2114        to find the match, as PCRE was deluded into thinking that the match had to
2115        start at the start point or following a newline. The same bug applied to
2116        patterns with negative forward assertions or any backward assertions
2117        preceding ".*" at the start, unless the pattern required a fixed first
2118        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2120    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2121        starting at the last subject character, bytes beyond the end of the subject
2122        string were read.
2124    11. Renamed the variable "class" as "classbits" to make life easier for C++
2125        users. (Previously there was a macro definition, but it apparently wasn't
2126        enough.)
2128    12. Added the new field "tables" to the extra data so that tables can be passed
2129        in at exec time, or the internal tables can be re-selected. This allows
2130        a compiled regex to be saved and re-used at a later time by a different
2131        program that might have everything at different addresses.
2133    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2134        -R library as well as a -L library.
2136    14. The debugging options of pcretest (-d on the command line or D on a
2137        pattern) showed incorrect output for anything following an extended class
2138        that contained multibyte characters and which was followed by a quantifier.
2140    15. Added optional support for general category Unicode character properties
2141        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2142        support. It adds about 90K to the size of the library. The meanings of the
2143        inbuilt class escapes such as \d and \s have NOT been changed.
2145    16. Updated pcredemo.c to include calls to free() to release the memory for the
2146        compiled pattern.
2148    17. The generated file chartables.c was being created in the source directory
2149        instead of in the building directory. This caused the build to fail if the
2150        source directory was different from the building directory, and was
2151        read-only.
2153    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2154        file. No doubt somebody will tell me if they don't make sense... Also added
2155        Dan Mooney's comments about building on OpenVMS.
2157    19. Added support for partial matching via the PCRE_PARTIAL option for
2158        pcre_exec() and the \P data escape in pcretest.
2160    20. Extended pcretest with 3 new pattern features:
2162        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2163              write the compiled pattern to the file whose name is "rest-of-line".
2164              This is a straight binary dump of the data, with the saved pointer to
2165              the character tables forced to be NULL. The study data, if any, is
2166              written too. After writing, pcretest reads a new pattern.
2168        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2169              compiled pattern from the given file. There must not be any
2170              occurrences of "<" in the file name (pretty unlikely); if there are,
2171              pcretest will instead treat the initial "<" as a pattern delimiter.
2172              After reading in the pattern, pcretest goes on to read data lines as
2173              usual.
2175        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2176              and 16-bit fields in a compiled pattern, to simulate a pattern that
2177              was compiled on a host of opposite endianness.
2179    21. The pcre-exec() function can now cope with patterns that were compiled on
2180        hosts of opposite endianness, with this restriction:
2182          As for any compiled expression that is saved and used later, the tables
2183          pointer field cannot be preserved; the extra_data field in the arguments
2184          to pcre_exec() should be used to pass in a tables address if a value
2185          other than the default internal tables were used at compile time.
2187    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2188        now diagnosed as an error. Previously, most of the time, a negative number
2189        would have been treated as zero, but if in addition "ovector" was passed as
2190        NULL, a crash could occur.
2192    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2193        new versions from the libtool 1.5 distribution (the last one is a copy of
2194        a file called libtool.m4). This seems to have fixed the need to patch
2195        "configure" to support Darwin 1.3 (which I used to do). However, I still
2196        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2197        workstation).
2199    24. Changed the PCRE licence to be the more standard "BSD" licence.
2202    Version 4.5 01-Dec-03
2203    ---------------------
2205     1. There has been some re-arrangement of the code for the match() function so
2206        that it can be compiled in a version that does not call itself recursively.
2207        Instead, it keeps those local variables that need separate instances for
2208        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2209        needs to "recurse". Keeping track of where control must go is done by means
2210        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2211        hide most of the details from the main code, and operates only if
2212        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2213        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2214        operating.
2216        To make it easier for callers to provide specially tailored get/free
2217        functions for this usage, two new functions, pcre_stack_malloc, and
2218        pcre_stack_free, are used. They are always called in strict stacking order,
2219        and the size of block requested is always the same.
2221        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2222        PCRE has been compiled to use the stack or the heap for recursion. The
2223        -C option of pcretest uses this to show which version is compiled.
2225        A new data escape \S, is added to pcretest; it causes the amounts of store
2226        obtained and freed by both kinds of malloc/free at match time to be added
2227        to the output.
2229     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2230        what's available on my current Linux desktop machine.
2232     3. When matching a UTF-8 string, the test for a valid string at the start has
2233        been extended. If start_offset is not zero, PCRE now checks that it points
2234        to a byte that is the start of a UTF-8 character. If not, it returns
2235        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2236        this is necessary because there may be backward assertions in the pattern.
2237        When matching the same subject several times, it may save resources to use
2238        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2240     4. The code for checking the validity of UTF-8 strings has been tightened so
2241        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2242        containing "overlong sequences".
2244     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2245        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2246        should have been "&", but it just so happened that all the cases this let
2247        through by mistake were picked up later in the function.
2249     6. I had used a variable called "isblank" - this is a C99 function, causing
2250        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2252     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2253        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2254        so the version is shown; (c) stop "make test" echoing "./RunTest".
2256     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2258     9. The prototype for memmove() for systems that don't have it was using
2259        size_t, but the inclusion of the header that defines size_t was later. I've
2260        moved the #includes for the C headers earlier to avoid this.
2262    10. Added some adjustments to the code to make it easier to compiler on certain
2263        special systems:
2265          (a) Some "const" qualifiers were missing.
2266          (b) Added the macro EXPORT before all exported functions; by default this
2267              is defined to be empty.
2268          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2269              that it reads its output file name as an argument instead of writing
2270              to the standard output and assuming this can be redirected.
2272    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2273        class containing characters with values greater than 255, PCRE compilation
2274        went into a loop.
2276    12. A recursive reference to a subpattern that was within another subpattern
2277        that had a minimum quantifier of zero caused PCRE to crash. For example,
2278        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2279        recursion. If the recursively-called subpattern itself had a zero repeat,
2280        that was OK.
2282    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2283        buffer into which it was copied (for escape processing) was still set at
2284        1024, so long lines caused crashes.
2286    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2287        "internal error: code overflow...". This applied to any character class
2288        that was followed by a possessive quantifier.
2290    15. Modified the Makefile to add libpcre.la as a prerequisite for
2291        libpcreposix.la because I was told this is needed for a parallel build to
2292        work.
2294    16. If a pattern that contained .* following optional items at the start was
2295        studied, the wrong optimizing data was generated, leading to matching
2296        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2297        matching string must start with a or b or c. The correct conclusion for
2298        this pattern is that a match can start with any character.
2301    Version 4.4 13-Aug-03
2302    ---------------------
2304     1. In UTF-8 mode, a character class containing characters with values between
2305        127 and 255 was not handled correctly if the compiled pattern was studied.
2306        In fixing this, I have also improved the studying algorithm for such
2307        classes (slightly).
2309     2. Three internal functions had redundant arguments passed to them. Removal
2310        might give a very teeny performance improvement.
2312     3. Documentation bug: the value of the capture_top field in a callout is *one
2313        more than* the number of the hightest numbered captured substring.
2315     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2316        in incorrectly linking with a previously installed version. They now link
2317        explicitly with libpcre.la.
2319     5. configure.in no longer needs to recognize Cygwin specially.
2321     6. A problem in pcre.in for Windows platforms is fixed.
2323     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2324        pcretest, it used to include the size of the study block as part of its
2325        output. Unfortunately, the structure contains a field that has a different
2326        size on different hardware architectures. This meant that the tests that
2327        showed this size failed. As the block is currently always of a fixed size,
2328        this information isn't actually particularly useful in pcretest output, so
2329        I have just removed it.
2331     8. Three pre-processor statements accidentally did not start in column 1.
2332        Sadly, there are *still* compilers around that complain, even though
2333        standard C has not required this for well over a decade. Sigh.
2335     9. In pcretest, the code for checking callouts passed small integers in the
2336        callout_data field, which is a void * field. However, some picky compilers
2337        complained about the casts involved for this on 64-bit systems. Now
2338        pcretest passes the address of the small integer instead, which should get
2339        rid of the warnings.
2341    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2342        both compile and run time, and gives an error if an invalid UTF-8 sequence
2343        is found. There is a option for disabling this check in cases where the
2344        string is known to be correct and/or the maximum performance is wanted.
2346    11. In response to a bug report, I changed one line in Makefile.in from
2348            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2349        to
2350            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2352        to look similar to other lines, but I have no way of telling whether this
2353        is the right thing to do, as I do not use Windows. No doubt I'll get told
2354        if it's wrong...
2357    Version 4.3 21-May-03
2358    ---------------------
2360    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2361       Makefile.
2363    2. Some refactoring to improve the quality of the code:
2365       (i)   The utf8_table... variables are now declared "const".
2367       (ii)  The code for \cx, which used the "case flipping" table to upper case
2368             lower case letters, now just substracts 32. This is ASCII-specific,
2369             but the whole concept of \cx is ASCII-specific, so it seems
2370             reasonable.
2372       (iii) PCRE was using its character types table to recognize decimal and
2373             hexadecimal digits in the pattern. This is silly, because it handles
2374             only 0-9, a-f, and A-F, but the character types table is locale-
2375             specific, which means strange things might happen. A private
2376             table is now used for this - though it costs 256 bytes, a table is
2377             much faster than multiple explicit tests. Of course, the standard
2378             character types table is still used for matching digits in subject
2379             strings against \d.
2381       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2382             ending in _t are). So I've renamed it as ESC_tee.
2384    3. The first argument for regexec() in the POSIX wrapper should have been
2385       defined as "const".
2387    4. Changed pcretest to use malloc() for its buffers so that they can be
2388       Electric Fenced for debugging.
2390    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2391       to read one or more bytes before the start of the subject string. Often this
2392       had no effect on PCRE's behaviour, but in some circumstances it could
2393       provoke a segmentation fault.
2395    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2396       to try to read one or more bytes before the start of the subject string.
2398    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2399       UTF-8 support could misbehave in various ways if the subject string
2400       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2401       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2402       back over UTF-8 characters.)
2405    Version 4.2 14-Apr-03
2406    ---------------------
2408    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2410    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2411         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2412         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2413         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2414         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2415           and BUILD_EXEEXT
2416         Note: automatic setting of the BUILD variables is not yet working
2417         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2418           compile-time but not at link-time
2419         [LINK]: use for linking executables only
2420         make different versions for Windows and non-Windows
2421         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2422           libraries
2423         [LINK_FOR_BUILD]: new variable
2424         [OBJEXT]: use throughout
2425         [EXEEXT]: use throughout
2426         <winshared>: new target
2427         <wininstall>: new target
2428         <dftables.o>: use native compiler
2429         <dftables>: use native linker
2430         <install>: handle Windows platform correctly
2431         <clean>: ditto
2432         <check>: ditto
2433         copy DLL to top builddir before testing
2435       As part of these changes, -no-undefined was removed again. This was reported
2436       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2437       in any case.
2439    3. Some tidies to get rid of compiler warnings:
2441       . In the match_data structure, match_limit was an unsigned long int, whereas
2442         match_call_count was an int. I've made them both unsigned long ints.
2444       . In pcretest the fact that a const uschar * doesn't automatically cast to
2445         a void * provoked a warning.
2447       . Turning on some more compiler warnings threw up some "shadow" variables
2448         and a few more missing casts.
2450    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2451       option, a class that contained a single character with a value between 128
2452       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2454    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2455       option, a class that contained several characters, but with at least one
2456       whose value was between 128 and 255 caused PCRE to crash.
2459    Version 4.1 12-Mar-03
2460    ---------------------
2462    1. Compiling with gcc -pedantic found a couple of places where casts were
2463    needed, and a string in dftables.c that was longer than standard compilers are
2464    required to support.
2466    2. Compiling with Sun's compiler found a few more places where the code could
2467    be tidied up in order to avoid warnings.
2469    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2470    first of these names is deprecated in the latest Autoconf in favour of the name
2471    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2472    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2473    analogy I have changed it to CFLAGS_FOR_BUILD.
2475    4. Added -no-undefined to the linking command in the Makefile, because this is
2476    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2477    linking step for the pcreposix library.
2479    5. PCRE was failing to diagnose the case of two named groups with the same
2480    name.
2482    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2483    literal character that is needed in the subject for a match, and scans along to
2484    ensure that it is present before embarking on the full matching process. This
2485    saves time in cases of nested unlimited repeats that are never going to match.
2486    Problem: the scan can take a lot of time if the subject is very long (e.g.
2487    megabytes), thus penalizing straightforward matches. It is now done only if the
2488    amount of subject to be scanned is less than 1000 bytes.
2490    7. A lesser problem with the same optimization is that it was recording the
2491    first character of an anchored pattern as "needed", thus provoking a search
2492    right along the subject, even when the first match of the pattern was going to
2493    fail. The "needed" character is now not set for anchored patterns, unless it
2494    follows something in the pattern that is of non-fixed length. Thus, it still
2495    fulfils its original purpose of finding quick non-matches in cases of nested
2496    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2499    Version 4.0 17-Feb-03
2500    ---------------------
2502    1. If a comment in an extended regex that started immediately after a meta-item
2503    extended to the end of string, PCRE compiled incorrect data. This could lead to
2504    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2506    2. Moved to autoconf 2.53 and libtool 1.4.2.
2508    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2509    the special perltest8 script is no longer needed - all the tests can be run
2510    from a single perltest script.
2512    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2513    by \s. It has now been removed in PCRE. This means it isn't recognized as
2514    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2515    class [:space:] *does* include VT, thereby creating a mess.
2517    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2518    space and tab.
2520    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2521    its new features into the main test script, reducing the number of scripts.
2523    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2524    were backward compatible, and made the (?i) apply to the whole pattern, as if
2525    /i were given. Now it behaves more logically, and applies the option setting
2526    only to what follows. PCRE has been changed to follow suit. However, if it
2527    finds options settings right at the start of the pattern, it extracts them into
2528    the global options, as before. Thus, they show up in the info data.
2530    8. Added support for the \Q...\E escape sequence. Characters in between are
2531    treated as literals. This is slightly different from Perl in that $ and @ are
2532    also handled as literals inside the quotes. In Perl, they will cause variable
2533    interpolation. Note the following examples:
2535        Pattern            PCRE matches      Perl matches
2537        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2538        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2539        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2541    For compatibility with Perl, \Q...\E sequences are recognized inside character
2542    classes as well as outside them.
2544    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2545    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2546    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2547    signed/unsigned warnings.
2549    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2550    option for pcretest, so I've replaced it by a simple function that does just
2551    that job.
2553    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2554    "pcregrep -".
2556    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2557    Java package. This provides some syntactic sugar for simple cases of what my
2558    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2559    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2560    item, you can use this simplified notation. Note that only makes sense with
2561    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2562    greediness, whatever the setting of the PCRE_UNGREEDY option.
2564    13. A change of greediness default within a pattern was not taking effect at
2565    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2566    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2567    was abstracted outside.
2569    14. PCRE now supports the \G assertion. It is true when the current matching
2570    position is at the start point of the match. This differs from \A when the
2571    starting offset is non-zero. Used with the /g option of pcretest (or similar
2572    code), it works in the same way as it does for Perl's /g option. If all
2573    alternatives of a regex begin with \G, the expression is anchored to the start
2574    match position, and the "anchored" flag is set in the compiled expression.
2576    15. Some bugs concerning the handling of certain option changes within patterns
2577    have been fixed. These applied to options other than (?ims). For example,
2578    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2579    been the other way round. Some of this was related to change 7 above.
2581    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2582    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2583    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2584    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2586    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2587    mode. Unlike ".", it always matches newline, whatever the setting of
2588    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2589    assertions. Perl allows it, but it doesn't (in general) work because it can't
2590    calculate the length of the lookbehind. At least, that's the case for Perl
2591    5.8.0 - I've been told they are going to document that it doesn't work in
2592    future.
2594    18. Added an error diagnosis for escapes that PCRE does not support: these are
2595    \L, \l, \N, \P, \p, \U, \u, and \X.
2597    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2598    reading past the end of the pattern in cases such as /[abcd/.
2600    20. PCRE was getting more memory than necessary for patterns with classes that
2601    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2603    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2604    compiling PCRE for use with Virtual Pascal.
2606    22. Small fix to the Makefile to make it work properly if the build is done
2607    outside the source tree.
2609    23. Added a new extension: a condition to go with recursion. If a conditional
2610    subpattern starts with (?(R) the "true" branch is used if recursion has
2611    happened, whereas the "false" branch is used only at the top level.
2613    24. When there was a very long string of literal characters (over 255 bytes
2614    without UTF support, over 250 bytes with UTF support), the computation of how
2615    much memory was required could be incorrect, leading to segfaults or other
2616    strange effects.
2618    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2619    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2620    there was a subsequent back reference to those brackets. This meant that, for
2621    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2622    possible to check for precisely this case. All we can do is abandon the
2623    optimization if .* occurs inside capturing brackets when there are any back
2624    references whatsoever. (See below for a better fix that came later.)
2626    26. The handling of the optimization for finding the first character of a
2627    non-anchored pattern, and for finding a character that is required later in the
2628    match were failing in some cases. This didn't break the matching; it just
2629    failed to optimize when it could. The way this is done has been re-implemented.
2631    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2633    28. Added a new feature that provides some of the functionality that Perl
2634    provides with (?{...}). The facility is termed a "callout". The way it is done
2635    in PCRE is for the caller to provide an optional function, by setting
2636    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2637    global variable. By default it is unset, which disables all calling out. To get
2638    the function called, the regex must include (?C) at appropriate points. This
2639    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2640    This provides a means of identifying different callout points. When PCRE
2641    reaches such a point in the regex, if pcre_callout has been set, the external
2642    function is called. It is provided with data in a structure called
2643    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2644    matching continues; if it returns a non-zero value, the match at the current
2645    point fails. However, backtracking will occur if possible. [This was changed
2646    later and other features added - see item 49 below.]
2648    29. pcretest is upgraded to test the callout functionality. It provides a
2649    callout function that displays information. By default, it shows the start of
2650    the match and the current position in the text. There are some new data escapes
2651    to vary what happens:
2653        \C+         in addition, show current contents of captured substrings
2654        \C-         do not supply a callout function
2655        \C!n        return 1 when callout number n is reached
2656        \C!n!m      return 1 when callout number n is reached for the mth time
2658    30. If pcregrep was called with the -l option and just a single file name, it
2659    output "<stdin>" if a match was found, instead of the file name.
2661    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2662    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2663    pcre_exec(). This saves a malloc/free per call. The default value of
2664    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2665    when configuring.
2667    32. The default maximum size of a compiled pattern is 64K. There have been a
2668    few cases of people hitting this limit. The code now uses macros to handle the
2669    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2670    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2671    configuring. Tests 2 and 5 work only with 2-byte links because they output
2672    debugging information about compiled patterns.
2674    33. Internal code re-arrangements:
2676    (a) Moved the debugging function for printing out a compiled regex into
2677        its own source file (printint.c) and used #include to pull it into
2678        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2679        separate copies.
2681    (b) Defined the list of op-code names for debugging as a macro in
2682        internal.h so that it is next to the definition of the opcodes.
2684    (c) Defined a table of op-code lengths for simpler skipping along compiled
2685        code. This is again a macro in internal.h so that it is next to the
2686        definition of the opcodes.
2688    34. Added support for recursive calls to individual subpatterns, along the
2689    lines of Robin Houston's patch (but implemented somewhat differently).
2691    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2692    allow it to read and process whole directories in Win32. This code was
2693    contributed by Lionel Fourquaux; it has not been tested by me.
2695    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2696    used to name a group. Names consist of alphanumerics and underscores, and must
2697    be unique. Back references use the syntax (?P=name) and recursive calls use
2698    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2699    numbers. The function pcre_fullinfo() can be used after compilation to extract
2700    a name/number map. There are three relevant calls:
2702      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2703      PCRE_INFO_NAMECOUNT            yields the number of entries
2704      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2706    The map is a vector of fixed-size entries. The size of each entry depends on
2707    the length of the longest name used. The first two bytes of each entry are the
2708    group number, most significant byte first. There follows the corresponding
2709    name, zero terminated. The names are in alphabetical order.
2711    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2712    case instead of 255. Making it the same both with and without UTF-8 support
2713    means that the same test output works with both.
2715    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2716    calling malloc() with a zero argument.
2718    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2719    optimization. I've improved things by keeping a bitmap of backreferences with
2720    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2721    fact referenced, the optimization can be applied. It is unlikely that a
2722    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2723    the match to follow \n) will appear inside brackets with a number greater than
2724    31, but if it does, any back reference > 31 suppresses the optimization.
2726    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2727    of disabling numbered capturing parentheses. Any opening parenthesis that is
2728    not followed by ? behaves as if it were followed by ?: but named parentheses
2729    can still be used for capturing (and they will acquire numbers in the usual
2730    way).
2732    41. Redesigned the return codes from the match() function into yes/no/error so
2733    that errors can be passed back from deep inside the nested calls. A malloc
2734    failure while inside a recursive subpattern call now causes the
2735    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2737    42. It is now possible to set a limit on the number of times the match()
2738    function is called in a call to pcre_exec(). This facility makes it possible to
2739    limit the amount of recursion and backtracking, though not in a directly
2740    obvious way, because the match() function is used in a number of different
2741    circumstances. The count starts from zero for each position in the subject
2742    string (for non-anchored patterns). The default limit is, for compatibility, a
2743    large number, namely 10 000 000. You can change this in two ways:
2745    (a) When configuring PCRE before making, you can use --with-match-limit=n
2746        to set a default value for the compiled library.
2748    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2749        a different value is set. See 45 below.
2751    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2753    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2754    of things that can be changed at compile time. The first argument specifies
2755    what is wanted and the second points to where the information is to be placed.
2756    The current list of available information is:
2758      PCRE_CONFIG_UTF8
2760    The output is an integer that is set to one if UTF-8 support is available;
2761    otherwise it is set to zero.
2765    The output is an integer that it set to the value of the code that is used for
2766    newline. It is either LF (10) or CR (13).
2770    The output is an integer that contains the number of bytes used for internal
2771    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2775    The output is an integer that contains the threshold above which the POSIX
2776    interface uses malloc() for output vectors. See item 31 above.
2780    The output is an unsigned integer that contains the default limit of the number
2781    of match() calls in a pcre_exec() execution. See 42 above.
2783    44. pcretest has been upgraded by the addition of the -C option. This causes it
2784    to extract all the available output from the new pcre_config() function, and to
2785    output it. The program then exits immediately.
2787    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2788    order to support additional features. One way would have been to define
2789    pcre_exec2() (for example) with extra arguments, but this would not have been
2790    extensible, and would also have required all calls to the original function to
2791    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2792    is used for passing in "extra" data from pcre_study().
2794    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2795    contains the following fields:
2797      flags         a bitmap indicating which of the following fields are set
2798      study_data    opaque data from pcre_study()
2799      match_limit   a way of specifying a limit on match() calls for a specific
2800                      call to pcre_exec()
2801      callout_data  data for callouts (see 49 below)
2803    The flag bits are also defined in pcre.h, and are
2809    The pcre_study() function now returns one of these new pcre_extra blocks, with
2810    the actual study data pointed to by the study_data field, and the
2811    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2812    before. That is, this change is entirely upwards-compatible and requires no
2813    change to existing code.
2815    If you want to pass in additional data to pcre_exec(), you can either place it
2816    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2817    block.
2819    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2820    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2821    times with different match limits, until it finds the minimum value needed for
2822    pcre_exec() to complete. The value is then output. This can be instructive; for
2823    most simple matches the number is quite small, but for pathological cases it
2824    gets very large very quickly.
2826    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2827    returns the size of the data block pointed to by the study_data field in a
2828    pcre_extra block, that is, the value that was passed as the argument to
2829    pcre_malloc() when PCRE was getting memory in which to place the information
2830    created by pcre_study(). The fourth argument should point to a size_t variable.
2831    pcretest has been extended so that this information is shown after a successful
2832    pcre_study() call when information about the compiled regex is being displayed.
2834    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2835    because what follows is always an absolute path. (Later: it turns out that this
2836    is more than cosmetic for MinGW, because it doesn't like empty path
2837    components.)
2839    49. Some changes have been made to the callout feature (see 28 above):
2841    (i)  A callout function now has three choices for what it returns:
2843           0  =>  success, carry on matching
2844         > 0  =>  failure at this point, but backtrack if possible
2845         < 0  =>  serious error, return this value from pcre_exec()
2847         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2848         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2849         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2850         use by callout functions. It will never be used by PCRE itself.
2852    (ii) The pcre_extra structure (see 45 above) has a void * field called
2853         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2854         pcre_callout_block structure has a field of the same name. The contents of
2855         the field passed in the pcre_extra structure are passed to the callout
2856         function in the corresponding field in the callout block. This makes it
2857         easier to use the same callout-containing regex from multiple threads. For
2858         testing, the pcretest program has a new data escape
2860           \C*n        pass the number n (may be negative) as callout_data
2862         If the callout function in pcretest receives a non-zero value as
2863         callout_data, it returns that value.
2865    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2866    there were some redundant $(CFLAGS) in commands that are now specified as
2867    $(LINK), which already includes $(CFLAGS).
2869    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2870    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2871    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2872    one-byte characters throughout. Note that case-insensitive matching applies
2873    only to characters whose values are less than 256. PCRE doesn't support the
2874    notion of cases for higher-valued characters.
2876    (i)   A character class whose characters are all within 0-255 is handled as
2877          a bit map, and the map is inverted for negative classes. Previously, a
2878          character > 255 always failed to match such a class; however it should
2879          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2881    (ii)  A negated character class with a single character < 255 is coded as
2882          "not this character" (OP_NOT). This wasn't working properly when the test
2883          character was multibyte, either singly or repeated.
2885    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2886          mode, for example: \x{100}{2,3}.
2888    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2889          singly or repeated) now correctly test multibyte characters. However,
2890          PCRE doesn't recognize any characters with values greater than 255 as
2891          digits, spaces, or word characters. Such characters always match \D, \S,
2892          and \W, and never match \d, \s, or \w.
2894    (v)   Classes may now contain characters and character ranges with values
2895          greater than 255. For example: [ab\x{100}-\x{400}].
2897    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2898          PCRE in UTF-8 mode.
2900    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2901    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2902    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2903    value.)
2905    53. The single man page has become too large. I have therefore split it up into
2906    a number of separate man pages. These also give rise to individual HTML pages;
2907    these are now put in a separate directory, and there is an index.html page that
2908    lists them all. Some hyperlinking between the pages has been installed.
2910    54. Added convenience functions for handling named capturing parentheses.
2912    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2913    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2914    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2915    are faulted.
2917    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2918    calling configure. These values are used when compiling the dftables.c program
2919    which is run to generate the source of the default character tables. They
2920    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2921    you will need to set these values.
2923    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2926    Version 3.9 02-Jan-02
2927  ---------------------  ---------------------
2929  1. A bit of extraneous text had somehow crept into the pcregrep documentation.  1. A bit of extraneous text had somehow crept into the pcregrep documentation.

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