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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.01 11-Dec-09
5    ----------------------
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
13    Version 8.00 19-Oct-09
14    ----------------------
16    1.  The table for translating pcre_compile() error codes into POSIX error codes
17        was out-of-date, and there was no check on the pcre_compile() error code
18        being within the table. This could lead to an OK return being given in
19        error.
21    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
22        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
23        in a Windows environment.
25    3.  The pcregrep --count option prints the count for each file even when it is
26        zero, as does GNU grep. However, pcregrep was also printing all files when
27        --files-with-matches was added. Now, when both options are given, it prints
28        counts only for those files that have at least one match. (GNU grep just
29        prints the file name in this circumstance, but including the count seems
30        more useful - otherwise, why use --count?) Also ensured that the
31        combination -clh just lists non-zero counts, with no names.
33    4.  The long form of the pcregrep -F option was incorrectly implemented as
34        --fixed_strings instead of --fixed-strings. This is an incompatible change,
35        but it seems right to fix it, and I didn't think it was worth preserving
36        the old behaviour.
38    5.  The command line items --regex=pattern and --regexp=pattern were not
39        recognized by pcregrep, which required --regex pattern or --regexp pattern
40        (with a space rather than an '='). The man page documented the '=' forms,
41        which are compatible with GNU grep; these now work.
43    6.  No libpcreposix.pc file was created for pkg-config; there was just
44        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
46    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
47        when UCP support is not needed, by modifying the Python script that
48        generates it from Unicode data files. This should not matter if the module
49        is correctly used as a library, but I received one complaint about 50K of
50        unwanted data. My guess is that the person linked everything into his
51        program rather than using a library. Anyway, it does no harm.
53    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
54        was a minimum greater than 1 for a wide character in a possessive
55        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
56        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
57        character. Chaos in the form of incorrect output or a compiling loop could
58        result.
60    9.  The restrictions on what a pattern can contain when partial matching is
61        requested for pcre_exec() have been removed. All patterns can now be
62        partially matched by this function. In addition, if there are at least two
63        slots in the offset vector, the offset of the earliest inspected character
64        for the match and the offset of the end of the subject are set in them when
65        PCRE_ERROR_PARTIAL is returned.
67    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
68        synonymous with PCRE_PARTIAL, for backwards compatibility, and
69        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
70        and may be more useful for multi-segment matching.
72    11. Partial matching with pcre_exec() is now more intuitive. A partial match
73        used to be given if ever the end of the subject was reached; now it is
74        given only if matching could not proceed because another character was
75        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
76        string "Z", which now yields "no match" instead of "partial match". In the
77        case of pcre_dfa_exec(), "no match" is given if every matching path for the
78        final character ended with (*FAIL).
80    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
81        if the pattern had a "must contain" character that was already found in the
82        earlier partial match, unless partial matching was again requested. For
83        example, with the pattern /dog.(body)?/, the "must contain" character is
84        "g". If the first part-match was for the string "dog", restarting with
85        "sbody" failed. This bug has been fixed.
87    13. The string returned by pcre_dfa_exec() after a partial match has been
88        changed so that it starts at the first inspected character rather than the
89        first character of the match. This makes a difference only if the pattern
90        starts with a lookbehind assertion or \b or \B (\K is not supported by
91        pcre_dfa_exec()). It's an incompatible change, but it makes the two
92        matching functions compatible, and I think it's the right thing to do.
94    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
95        so that the demonstration program is easily available in environments where
96        PCRE has not been installed from source.
98    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
99        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
100        library.
102    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
103        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
104        is not the first non-POSIX option to be added. Clearly some people find
105        these options useful.
107    17. If a caller to the POSIX matching function regexec() passes a non-zero
108        value for nmatch with a NULL value for pmatch, the value of
109        nmatch is forced to zero.
111    18. RunGrepTest did not have a test for the availability of the -u option of
112        the diff command, as RunTest does. It now checks in the same way as
113        RunTest, and also checks for the -b option.
115    19. If an odd number of negated classes containing just a single character
116        interposed, within parentheses, between a forward reference to a named
117        subpattern and the definition of the subpattern, compilation crashed with
118        an internal error, complaining that it could not find the referenced
119        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
120        [The bug was that it was starting one character too far in when skipping
121        over the character class, thus treating the ] as data rather than
122        terminating the class. This meant it could skip too much.]
124    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
125        /g option in pcretest when the pattern contains \K, which makes it possible
126        to have an empty string match not at the start, even when the pattern is
127        anchored. Updated pcretest and pcredemo to use this option.
129    21. If the maximum number of capturing subpatterns in a recursion was greater
130        than the maximum at the outer level, the higher number was returned, but
131        with unset values at the outer level. The correct (outer level) value is
132        now given.
134    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
135        PCRE did not set those parentheses (unlike Perl). I have now found a way to
136        make it do so. The string so far is captured, making this feature
137        compatible with Perl.
139    23. The tests have been re-organized, adding tests 11 and 12, to make it
140        possible to check the Perl 5.10 features against Perl 5.10.
142    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
143        pattern matches a fixed length string. PCRE did not allow this; now it
144        does. Neither allows recursion.
146    25. I finally figured out how to implement a request to provide the minimum
147        length of subject string that was needed in order to match a given pattern.
148        (It was back references and recursion that I had previously got hung up
149        on.) This code has now been added to pcre_study(); it finds a lower bound
150        to the length of subject needed. It is not necessarily the greatest lower
151        bound, but using it to avoid searching strings that are too short does give
152        some useful speed-ups. The value is available to calling programs via
153        pcre_fullinfo().
155    26. While implementing 25, I discovered to my embarrassment that pcretest had
156        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
157        study optimizations had never been tested with that matching function.
158        Oops. What is worse, even when it was passed study data, there was a bug in
159        pcre_dfa_exec() that meant it never actually used it. Double oops. There
160        were also very few tests of studied patterns with pcre_dfa_exec().
162    27. If (?| is used to create subpatterns with duplicate numbers, they are now
163        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
164        on the other side of the coin, they are no longer allowed to have different
165        names, because these cannot be distinguished in PCRE, and this has caused
166        confusion. (This is a difference from Perl.)
168    28. When duplicate subpattern names are present (necessarily with different
169        numbers, as required by 27 above), and a test is made by name in a
170        conditional pattern, either for a subpattern having been matched, or for
171        recursion in such a pattern, all the associated numbered subpatterns are
172        tested, and the overall condition is true if the condition is true for any
173        one of them. This is the way Perl works, and is also more like the way
174        testing by number works.
177    Version 7.9 11-Apr-09
178    ---------------------
180    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
181        (pcretest), all targets were linked against these libraries. This included
182        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
183        libraries. This caused unwanted dependencies to be created. This problem
184        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
185        pcretest is linked with readline.
187    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
188        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
189        moved outside it again, because FALSE and TRUE are already defined in AIX,
190        but BOOL is not.
192    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
193        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
195    4.  The pcregrep documentation said spaces were inserted as well as colons (or
196        hyphens) following file names and line numbers when outputting matching
197        lines. This is not true; no spaces are inserted. I have also clarified the
198        wording for the --colour (or --color) option.
200    5.  In pcregrep, when --colour was used with -o, the list of matching strings
201        was not coloured; this is different to GNU grep, so I have changed it to be
202        the same.
204    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
205        each matching line was coloured. Now it goes on to look for further matches
206        of any of the test patterns, which is the same behaviour as GNU grep.
208    7.  A pattern that could match an empty string could cause pcregrep to loop; it
209        doesn't make sense to accept an empty string match in pcregrep, so I have
210        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
211        seems to be how GNU grep behaves.
213    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
214        start or after a newline", because the conditional assertion was not being
215        correctly handled. The rule now is that both the assertion and what follows
216        in the first alternative must satisfy the test.
218    9.  If auto-callout was enabled in a pattern with a conditional group whose
219        condition was an assertion, PCRE could crash during matching, both with
220        pcre_exec() and pcre_dfa_exec().
222    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
223        used for matching.
225    11. Unicode property support in character classes was not working for
226        characters (bytes) greater than 127 when not in UTF-8 mode.
228    12. Added the -M command line option to pcretest.
230    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
232    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
234    16. Added comments and documentation about mis-use of no_arg in the C++
235        wrapper.
237    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
238        from Martin Jerabek that uses macro names for all relevant character and
239        string constants.
241    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
242        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
243        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
244        these, but not everybody uses configure.
246    19. A conditional group that had only one branch was not being correctly
247        recognized as an item that could match an empty string. This meant that an
248        enclosing group might also not be so recognized, causing infinite looping
249        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
250        with the subject "ab", where knowledge that the repeated group can match
251        nothing is needed in order to break the loop.
253    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
254        exec(), but without supplying a callout function, matching went wrong.
256    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
257        leak if the size of the offset vector was greater than 30. When the vector
258        is smaller, the saved offsets during recursion go onto a local stack
259        vector, but for larger vectors malloc() is used. It was failing to free
260        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
261        error, in fact).
263    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
264        heapframe that is used only when UTF-8 support is enabled. This caused no
265        problem, but was untidy.
267    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
268        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
269        included within another project.
271    24. Steven Van Ingelgem's patches to add more options to the CMake support,
272        slightly modified by me:
274          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
275              not building pcregrep.
277          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
278              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
280    25. Forward references, both numeric and by name, in patterns that made use of
281        duplicate group numbers, could behave incorrectly or give incorrect errors,
282        because when scanning forward to find the reference group, PCRE was not
283        taking into account the duplicate group numbers. A pattern such as
284        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
286    26. Changed a few more instances of "const unsigned char *" to USPTR, making
287        the feature of a custom pointer more persuasive (as requested by a user).
289    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
290        pcretest.c, inside #ifndefs, because it seems they are sometimes already
291        pre-defined.
293    28. Added support for (*UTF8) at the start of a pattern.
295    29. Arrange for flags added by the "release type" setting in CMake to be shown
296        in the configuration summary.
299    Version 7.8 05-Sep-08
300    ---------------------
302    1.  Replaced UCP searching code with optimized version as implemented for Ad
303        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
304        stage table and inline lookup instead of a function, giving speed ups of 2
305        to 5 times on some simple patterns that I tested. Permission was given to
306        distribute the MultiStage2.py script that generates the tables (it's not in
307        the tarball, but is in the Subversion repository).
309    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
310        scripts.
312    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
313        a group with a zero qualifier. The result of the study could be incorrect,
314        or the function might crash, depending on the pattern.
316    4.  Caseless matching was not working for non-ASCII characters in back
317        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
318        It now works when Unicode Property Support is available.
320    5.  In pcretest, an escape such as \x{de} in the data was always generating
321        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
322        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
323        truncation.
325    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
327    7.  Added two (int) casts to pcregrep when printing the difference of two
328        pointers, in case they are 64-bit values.
330    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
331        test 2 if it fails.
333    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
334        and a #define of that name to empty if it is not externally set. This is to
335        allow users of MSVC to set it if necessary.
337    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
338        the convenience functions in the pcre_get.c source file.
340    11. An option change at the start of a pattern that had top-level alternatives
341        could cause overwriting and/or a crash. This command provoked a crash in
342        some environments:
344          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
346        This potential security problem was recorded as CVE-2008-2371.
348    12. For a pattern where the match had to start at the beginning or immediately
349        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
350        pcre_dfa_exec() could read past the end of the passed subject if there was
351        no match. To help with detecting such bugs (e.g. with valgrind), I modified
352        pcretest so that it places the subject at the end of its malloc-ed buffer.
354    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
355        exec() might read past the end of the data buffer in UTF-8 mode.
357    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
358        the data contained the byte 0x85 as part of a UTF-8 character within its
359        first line. This applied both to normal and DFA matching.
361    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
362        /^[^d]*?$/8 failed to match "abc".
364    16. Added a missing copyright notice to pcrecpp_internal.h.
366    17. Make it more clear in the documentation that values returned from
367        pcre_exec() in ovector are byte offsets, not character counts.
369    18. Tidied a few places to stop certain compilers from issuing warnings.
371    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
372        supplied by Stefan Weber. I made a further small update for 7.8 because
373        there is a change of source arrangements: the pcre_searchfuncs.c module is
374        replaced by pcre_ucd.c.
377    Version 7.7 07-May-08
378    ---------------------
380    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
381        a string to a long long, pretend we don't even have a long long." This is
382        done by checking for the strtoq, strtoll, and _strtoi64 functions.
384    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
385        pre-7.6 versions, which defined a global no_arg variable instead of putting
386        it in the RE class. (See also #8 below.)
388    3.  Remove a line of dead code, identified by coverity and reported by Nuno
389        Lopes.
391    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
393        (1) The include/exclude patterns were being applied to the whole pathnames
394            of files, instead of just to the final components.
396        (2) If there was more than one level of directory, the subdirectories were
397            skipped unless they satisfied the include/exclude conditions. This is
398            inconsistent with GNU grep (and could even be seen as contrary to the
399            pcregrep specification - which I improved to make it absolutely clear).
400            The action now is always to scan all levels of directory, and just
401            apply the include/exclude patterns to regular files.
403    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
404        --exclude_dir in the tests to avoid scanning .svn directories.
406    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
407        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
408        doesn't support NULs in patterns.
410    7.  Added some missing "const"s to declarations of static tables in
411        pcre_compile.c and pcre_dfa_exec.c.
413    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
414        caused by fix #2  above. (Subsequently also a second patch to fix the
415        first patch. And a third patch - this was a messy problem.)
417    9.  Applied Craig's patch to remove the use of push_back().
419    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
420        matching function regexec().
422    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
423        which, however, unlike Perl's \g{...}, are subroutine calls, not back
424        references. PCRE supports relative numbers with this syntax (I don't think
425        Oniguruma does).
427    12. Previously, a group with a zero repeat such as (...){0} was completely
428        omitted from the compiled regex. However, this means that if the group
429        was called as a subroutine from elsewhere in the pattern, things went wrong
430        (an internal error was given). Such groups are now left in the compiled
431        pattern, with a new opcode that causes them to be skipped at execution
432        time.
434    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
435        to the way PCRE behaves:
437        (a) A lone ] character is dis-allowed (Perl treats it as data).
439        (b) A back reference to an unmatched subpattern matches an empty string
440            (Perl fails the current match path).
442        (c) A data ] in a character class must be notated as \] because if the
443            first data character in a class is ], it defines an empty class. (In
444            Perl it is not possible to have an empty class.) The empty class []
445            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
446            The negative empty class [^] matches any one character, independently
447            of the DOTALL setting.
449    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
450        non-existent subpattern following a character class starting with ']' and
451        containing () gave an internal compiling error instead of "reference to
452        non-existent subpattern". Fortunately, when the pattern did exist, the
453        compiled code was correct. (When scanning forwards to check for the
454        existencd of the subpattern, it was treating the data ']' as terminating
455        the class, so got the count wrong. When actually compiling, the reference
456        was subsequently set up correctly.)
458    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
459        it was being rejected as not supported by pcre_dfa_exec(), even though
460        other assertions are supported. I have made pcre_dfa_exec() support
461        (*FAIL).
463    16. The implementation of 13c above involved the invention of a new opcode,
464        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
465        cannot be changed at match time, I realized I could make a small
466        improvement to matching performance by compiling OP_ALLANY instead of
467        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
468        on the OP_ANY path.
470    17. Compiling pcretest on Windows with readline support failed without the
471        following two fixes: (1) Make the unistd.h include conditional on
472        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
474    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
475        ncurses library to be included for pcretest when ReadLine support is
476        requested, but also to allow for it to be overridden. This patch came from
477        Daniel Bergström.
479    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
480        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
481        any errors with the current Unicode tables. Thanks to Peter Kankowski for
482        spotting this.
485    Version 7.6 28-Jan-08
486    ---------------------
488    1.  A character class containing a very large number of characters with
489        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
490        overflow.
492    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
493        HAVE_LONG_LONG is not defined.
495    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
496        bring them up to date and include new features. This patch includes:
498        - Fixed PH's badly added libz and libbz2 support.
499        - Fixed a problem with static linking.
500        - Added pcredemo. [But later removed - see 7 below.]
501        - Fixed dftables problem and added an option.
502        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
503            HAVE_LONG_LONG.
504        - Added readline support for pcretest.
505        - Added an listing of the option settings after cmake has run.
507    4.  A user submitted a patch to Makefile that makes it easy to create
508        "pcre.dll" under mingw when using Configure/Make. I added stuff to
509        Makefile.am that cause it to include this special target, without
510        affecting anything else. Note that the same mingw target plus all
511        the other distribution libraries and programs are now supported
512        when configuring with CMake (see 6 below) instead of with
513        Configure/Make.
515    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
516        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
517        exported in the Windows port". It has not yet been confirmed that the patch
518        solves the problem, but it does no harm.
520    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
521        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
522        with CMake, and also correct the comment about stack recursion.
524    7.  Remove the automatic building of pcredemo from the ./configure system and
525        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
526        of a program that users should build themselves after PCRE is installed, so
527        building it automatically is not really right. What is more, it gave
528        trouble in some build environments.
530    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
533    Version 7.5 10-Jan-08
534    ---------------------
536    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
537        values in parens when parsing an RE using the C++ wrapper."
539    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
540        Characters greater than 255 were excluded from the class instead of being
541        included.
543    3.  The same bug as (2) above applied to negated POSIX classes such as
544        [:^space:].
546    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
547        defined or documented. It seems to have been a typo for PCRE_STATIC, so
548        I have changed it.
550    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
551        first named subpattern) and a construct such as (?&a) would reference the
552        first named subpattern whose name started with "a" (in other words, the
553        length check was missing). Both these problems are fixed. "Subpattern name
554        expected" is now given for (?&) (a zero-length name), and this patch also
555        makes it give the same error for \k'' (previously it complained that that
556        was a reference to a non-existent subpattern).
558    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
559        this is right because (?- can be followed by option settings as well as by
560        digits. I have, however, made the messages clearer.
562    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
563        than the number used in the conditional) now cause a compile-time error.
564        This is actually not compatible with Perl, which accepts such patterns, but
565        treats the conditional as always being FALSE (as PCRE used to), but it
566        seems to me that giving a diagnostic is better.
568    8.  Change "alphameric" to the more common word "alphanumeric" in comments
569        and messages.
571    9.  Fix two occurrences of "backslash" in comments that should have been
572        "backspace".
574    10. Remove two redundant lines of code that can never be obeyed (their function
575        was moved elsewhere).
577    11. The program that makes PCRE's Unicode character property table had a bug
578        which caused it to generate incorrect table entries for sequences of
579        characters that have the same character type, but are in different scripts.
580        It amalgamated them into a single range, with the script of the first of
581        them. In other words, some characters were in the wrong script. There were
582        thirteen such cases, affecting characters in the following ranges:
584          U+002b0 - U+002c1
585          U+0060c - U+0060d
586          U+0061e - U+00612
587          U+0064b - U+0065e
588          U+0074d - U+0076d
589          U+01800 - U+01805
590          U+01d00 - U+01d77
591          U+01d9b - U+01dbf
592          U+0200b - U+0200f
593          U+030fc - U+030fe
594          U+03260 - U+0327f
595          U+0fb46 - U+0fbb1
596          U+10450 - U+1049d
598    12. The -o option (show only the matching part of a line) for pcregrep was not
599        compatible with GNU grep in that, if there was more than one match in a
600        line, it showed only the first of them. It now behaves in the same way as
601        GNU grep.
603    13. If the -o and -v options were combined for pcregrep, it printed a blank
604        line for every non-matching line. GNU grep prints nothing, and pcregrep now
605        does the same. The return code can be used to tell if there were any
606        non-matching lines.
608    14. Added --file-offsets and --line-offsets to pcregrep.
610    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
611        infinitely looping recursion. The bug was that positive lookaheads were not
612        being skipped when checking for a possible empty match (negative lookaheads
613        and both kinds of lookbehind were skipped).
615    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
616        inclusion of <windows.h> to before rather than after the definition of
617        INVALID_FILE_ATTRIBUTES (patch from David Byron).
619    17. Specifying a possessive quantifier with a specific limit for a Unicode
620        character property caused pcre_compile() to compile bad code, which led at
621        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
622        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
623        caused the error; without that there was no problem.
625    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
627    19. Added --enable-pcretest-libreadline.
629    20. In pcrecpp.cc, the variable 'count' was incremented twice in
630        RE::GlobalReplace(). As a result, the number of replacements returned was
631        double what it should be. I removed one of the increments, but Craig sent a
632        later patch that removed the other one (the right fix) and added unit tests
633        that check the return values (which was not done before).
635    21. Several CMake things:
637        (1) Arranged that, when cmake is used on Unix, the libraries end up with
638            the names libpcre and libpcreposix, not just pcre and pcreposix.
640        (2) The above change means that pcretest and pcregrep are now correctly
641            linked with the newly-built libraries, not previously installed ones.
645    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
646        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
647        UTF-8 newline character). The key issue is that the pattern starts .*;
648        this means that the match must be either at the beginning, or after a
649        newline. The bug was in the code for advancing after a failed match and
650        checking that the new position followed a newline. It was not taking
651        account of UTF-8 characters correctly.
653    23. PCRE was behaving differently from Perl in the way it recognized POSIX
654        character classes. PCRE was not treating the sequence [:...:] as a
655        character class unless the ... were all letters. Perl, however, seems to
656        allow any characters between [: and :], though of course it rejects as
657        unknown any "names" that contain non-letters, because all the known class
658        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
659        for example, whereas PCRE did not - it did not recognize a POSIX character
660        class. This seemed a bit dangerous, so the code has been changed to be
661        closer to Perl. The behaviour is not identical to Perl, because PCRE will
662        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
663        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
664        Perl does, and where it didn't before.
666    24. Rewrite so as to remove the single use of %n from pcregrep because in some
667        Windows environments %n is disabled by default.
670    Version 7.4 21-Sep-07
671    ---------------------
673    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
674        means that a class such as [\s] counted as "explicit reference to CR or
675        LF". That isn't really right - the whole point of the change was to try to
676        help when there was an actual mention of one of the two characters. So now
677        the change happens only if \r or \n (or a literal CR or LF) character is
678        encountered.
680    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
681        of both had grown to the point where there were only 3 bits left.
682        Fortunately, there was spare space in the data structure, and so I have
683        moved the internal flags into a new 16-bit field to free up more option
684        bits.
686    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
687        but did not set the internal JCHANGED flag - either of these is enough to
688        control the way the "get" function works - but the PCRE_INFO_JCHANGED
689        facility is supposed to tell if (?J) was ever used, so now (?J) at the
690        start sets both bits.
692    4.  Added options (at build time, compile time, exec time) to change \R from
693        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
695    5.  doc/pcresyntax.html was missing from the distribution.
697    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
698        compatibility, even though it is no longer used.
700    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
701        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
702        windows.h file is present (where different names are used). [This was
703        reversed later after testing - see 16 below.]
705    8.  Changed all #include <config.h> to #include "config.h". There were also
706        some further <pcre.h> cases that I changed to "pcre.h".
708    9.  When pcregrep was used with the --colour option, it missed the line ending
709        sequence off the lines that it output.
711    10. It was pointed out to me that arrays of string pointers cause lots of
712        relocations when a shared library is dynamically loaded. A technique of
713        using a single long string with a table of offsets can drastically reduce
714        these. I have refactored PCRE in four places to do this. The result is
715        dramatic:
717          Originally:                          290
718          After changing UCP table:            187
719          After changing error message table:   43
720          After changing table of "verbs"       36
721          After changing table of Posix names   22
723        Thanks to the folks working on Gregex for glib for this insight.
725    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
726        unicode-properties was also set.
728    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
730    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
731        checked only for CRLF.
733    14. Added casts to pcretest.c to avoid compiler warnings.
735    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
737    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
738        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
739        entirely. This removes changes made in 7 above.
741    17. The CMake files have been updated, and there is now more information about
742        building with CMake in the NON-UNIX-USE document.
745    Version 7.3 28-Aug-07
746    ---------------------
748     1. In the rejigging of the build system that eventually resulted in 7.1, the
749        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
750        brackets there is not right, since it causes compilers to look for an
751        installed pcre.h, not the version that is in the source that is being
752        compiled (which of course may be different). I have changed it back to:
754          #include "pcre.h"
756        I have a vague recollection that the change was concerned with compiling in
757        different directories, but in the new build system, that is taken care of
758        by the VPATH setting the Makefile.
760     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
761        when the subject happened to end in the byte 0x85 (e.g. if the last
762        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
763        characters but of course it shouldn't be taken as a newline when it is part
764        of another character. The bug was that, for an unlimited repeat of . in
765        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
766        characters when looking for a newline.
768     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
770     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
771        in debug output.
773     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
774        long printing in the pcrecpp unittest when running under MinGW.
776     6. ESC_K was left out of the EBCDIC table.
778     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
779        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
780        limit also applies to "virtual nesting" when a pattern is recursive, and in
781        this case 1000 isn't so big. I have been able to remove this limit at the
782        expense of backing off one optimization in certain circumstances. Normally,
783        when pcre_exec() would call its internal match() function recursively and
784        immediately return the result unconditionally, it uses a "tail recursion"
785        feature to save stack. However, when a subpattern that can match an empty
786        string has an unlimited repetition quantifier, it no longer makes this
787        optimization. That gives it a stack frame in which to save the data for
788        checking that an empty string has been matched. Previously this was taken
789        from the 1000-entry workspace that had been reserved. So now there is no
790        explicit limit, but more stack is used.
792     8. Applied Daniel's patches to solve problems with the import/export magic
793        syntax that is required for Windows, and which was going wrong for the
794        pcreposix and pcrecpp parts of the library. These were overlooked when this
795        problem was solved for the main library.
797     9. There were some crude static tests to avoid integer overflow when computing
798        the size of patterns that contain repeated groups with explicit upper
799        limits. As the maximum quantifier is 65535, the maximum group length was
800        set at 30,000 so that the product of these two numbers did not overflow a
801        32-bit integer. However, it turns out that people want to use groups that
802        are longer than 30,000 bytes (though not repeat them that many times).
803        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
804        made it possible to implement the integer overflow checks in a much more
805        dynamic way, which I have now done. The artificial limitation on group
806        length has been removed - we now have only the limit on the total length of
807        the compiled pattern, which depends on the LINK_SIZE setting.
809    10. Fixed a bug in the documentation for get/copy named substring when
810        duplicate names are permitted. If none of the named substrings are set, the
811        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
812        empty string.
814    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
815        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
816        because the ] is interpreted as the first data character and the
817        terminating ] is not found. PCRE has been made compatible with Perl in this
818        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
819        cause memory overwriting.
821    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
822        string has been matched (to stop an infinite loop). It was not recognizing
823        a conditional subpattern that could match an empty string if that
824        subpattern was within another subpattern. For example, it looped when
825        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
826        condition was not nested. This bug has been fixed.
828    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
829        past the start of the subject in the presence of bytes with the top bit
830        set, for example "\x8aBCD".
832    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
833        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
835    14. Optimized (?!) to (*FAIL).
837    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
838        This restricts code points to be within the range 0 to 0x10FFFF, excluding
839        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
840        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
841        does: it's just the validity check that is more restrictive.
843    16. Inserted checks for integer overflows during escape sequence (backslash)
844        processing, and also fixed erroneous offset values for syntax errors during
845        backslash processing.
847    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
848        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
850    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
851        caused an overrun.
853    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
854        something other than just ASCII characters) inside a group that had an
855        unlimited repeat caused a loop at compile time (while checking to see
856        whether the group could match an empty string).
858    20. Debugging a pattern containing \p or \P could cause a crash. For example,
859        [\P{Any}] did so. (Error in the code for printing property names.)
861    21. An orphan \E inside a character class could cause a crash.
863    22. A repeated capturing bracket such as (A)? could cause a wild memory
864        reference during compilation.
866    23. There are several functions in pcre_compile() that scan along a compiled
867        expression for various reasons (e.g. to see if it's fixed length for look
868        behind). There were bugs in these functions when a repeated \p or \P was
869        present in the pattern. These operators have additional parameters compared
870        with \d, etc, and these were not being taken into account when moving along
871        the compiled data. Specifically:
873        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
874            length.
876        (b) An item such as \pL+ within a repeated group could cause crashes or
877            loops.
879        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
880            "reference to non-existent subpattern" error.
882        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
884    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
885        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
887    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
889    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
890        character were causing crashes (broken optimization).
892    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
893        \p or \P) caused a compile-time loop.
895    28. More problems have arisen in unanchored patterns when CRLF is a valid line
896        break. For example, the unstudied pattern [\r\n]A does not match the string
897        "\r\nA" because change 7.0/46 below moves the current point on by two
898        characters after failing to match at the start. However, the pattern \nA
899        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
900        the same is true. There doesn't seem any very clean way out of this, but
901        what I have chosen to do makes the common cases work: PCRE now takes note
902        of whether there can be an explicit match for \r or \n anywhere in the
903        pattern, and if so, 7.0/46 no longer applies. As part of this change,
904        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
905        pattern has explicit CR or LF references.
907    29. Added (*CR) etc for changing newline setting at start of pattern.
910    Version 7.2 19-Jun-07
911    ---------------------
913     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
914        which is apparently normally available under Windows.
916     2. Re-jig the pcregrep tests with different newline settings in an attempt
917        to make them independent of the local environment's newline setting.
919     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
921     4. Some of the "internals" tests were previously cut out when the link size
922        was not 2, because the output contained actual offsets. The recent new
923        "Z" feature of pcretest means that these can be cut out, making the tests
924        usable with all link sizes.
926     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
927        stack recursion. This gives a massive performance boost under BSD, but just
928        a small improvement under Linux. However, it saves one field in the frame
929        in all cases.
931     6. Added more features from the forthcoming Perl 5.10:
933        (a) (?-n) (where n is a string of digits) is a relative subroutine or
934            recursion call. It refers to the nth most recently opened parentheses.
936        (b) (?+n) is also a relative subroutine call; it refers to the nth next
937            to be opened parentheses.
939        (c) Conditions that refer to capturing parentheses can be specified
940            relatively, for example, (?(-2)... or (?(+3)...
942        (d) \K resets the start of the current match so that everything before
943            is not part of it.
945        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
947        (f) \g{name} is another synonym - part of Perl 5.10's unification of
948            reference syntax.
950        (g) (?| introduces a group in which the numbering of parentheses in each
951            alternative starts with the same number.
953        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
955     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
958     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
959        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
960        for detecting groups that can match an empty string.
962     9. A pattern with a very large number of alternatives (more than several
963        hundred) was running out of internal workspace during the pre-compile
964        phase, where pcre_compile() figures out how much memory will be needed. A
965        bit of new cunning has reduced the workspace needed for groups with
966        alternatives. The 1000-alternative test pattern now uses 12 bytes of
967        workspace instead of running out of the 4096 that are available.
969    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
971    11. Applied patch from Google to remove an optimization that didn't quite work.
972        The report of the bug said:
974          pcrecpp::RE("a*").FullMatch("aaa") matches, while
975          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
976          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
978    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
979        it matched the wrong number of bytes.
982    Version 7.1 24-Apr-07
983    ---------------------
985     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
986        that is more "standard", making use of automake and other Autotools. There
987        is some re-arrangement of the files and adjustment of comments consequent
988        on this.
990     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
991        for recursive directory scanning broke on some systems because the files
992        are not scanned in any specific order and on different systems the order
993        was different. A call to "sort" has been inserted into RunGrepTest for the
994        approprate test as a short-term fix. In the longer term there may be an
995        alternative.
997     3. I had an email from Eric Raymond about problems translating some of PCRE's
998        man pages to HTML (despite the fact that I distribute HTML pages, some
999        people do their own conversions for various reasons). The problems
1000        concerned the use of low-level troff macros .br and .in. I have therefore
1001        removed all such uses from the man pages (some were redundant, some could
1002        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1003        HTML has been updated to handle .nf/.fi and to complain if it encounters
1004        .br or .in.
1006     4. Updated comments in configure.ac that get placed in config.h.in and also
1007        arranged for config.h to be included in the distribution, with the name
1008        config.h.generic, for the benefit of those who have to compile without
1009        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1011     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1012        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1013        makevp.bat for the current PCRE, using the additional files
1014        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1016     6. A Windows user reported a minor discrepancy with test 2, which turned out
1017        to be caused by a trailing space on an input line that had got lost in his
1018        copy. The trailing space was an accident, so I've just removed it.
1020     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1021        that is needed.
1023     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1024        as "const" (a) because they are and (b) because it helps the PHP
1025        maintainers who have recently made a script to detect big data structures
1026        in the php code that should be moved to the .rodata section. I remembered
1027        to update Builducptable as well, so it won't revert if ucptable.h is ever
1028        re-created.
1030     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1031        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1032        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1033        support is not required. This saves 1.5-2K of code, which is important in
1034        some applications.
1036        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1037        so as not to refer to the tables, even though these functions will never be
1038        called when UTF-8 support is disabled. Otherwise there are problems with a
1039        shared library.
1041    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1043        (a) It was defining its arguments as char * instead of void *.
1045        (b) It was assuming that all moves were upwards in memory; this was true
1046            a long time ago when I wrote it, but is no longer the case.
1048        The emulated memove() is provided for those environments that have neither
1049        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1050        is clearly not the case, as these two bugs were recently reported.
1052    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1053        and Detrail to create the HTML documentation, the .txt form of the man
1054        pages, and it removes trailing spaces from listed files. It also creates
1055        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1056        case, it wraps all the #defines with #ifndefs. This script should be run
1057        before "make dist".
1059    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1060        with Unicode property support.
1062        (a) For a maximizing quantifier, if the two different cases of the
1063            character were of different lengths in their UTF-8 codings (there are
1064            some cases like this - I found 11), and the matching function had to
1065            back up over a mixture of the two cases, it incorrectly assumed they
1066            were both the same length.
1068        (b) When PCRE was configured to use the heap rather than the stack for
1069            recursion during matching, it was not correctly preserving the data for
1070            the other case of a UTF-8 character when checking ahead for a match
1071            while processing a minimizing repeat. If the check also involved
1072            matching a wide character, but failed, corruption could cause an
1073            erroneous result when trying to check for a repeat of the original
1074            character.
1076    13. Some tidying changes to the testing mechanism:
1078        (a) The RunTest script now detects the internal link size and whether there
1079            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1080            values substituted by "configure". (The RunGrepTest script already did
1081            this for UTF-8.) The configure.ac script no longer substitutes the
1082            relevant variables.
1084        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1085            with length and offset values. This means that the output is different
1086            for different internal link sizes. Test 2 is skipped for link sizes
1087            other than 2 because of this, bypassing the problem. Unfortunately,
1088            there was also a test in test 3 (the locale tests) that used /B and
1089            failed for link sizes other than 2. Rather than cut the whole test out,
1090            I have added a new /Z option to pcretest that replaces the length and
1091            offset values with spaces. This is now used to make test 3 independent
1092            of link size. (Test 2 will be tidied up later.)
1094    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1095        segmentation fault instead of returning the appropriate error message.
1097    15. In multiline mode when the newline sequence was set to "any", the pattern
1098        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1099        This doesn't seem right; it now treats the CRLF combination as the line
1100        ending, and so does not match in that case. It's only a pattern such as ^$
1101        that would hit this one: something like ^ABC$ would have failed after \r
1102        and then tried again after \r\n.
1104    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1105        in an attempt to make files that differ only in their line terminators
1106        compare equal. This works on Linux.
1108    17. Under certain error circumstances pcregrep might try to free random memory
1109        as it exited. This is now fixed, thanks to valgrind.
1111    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1112        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1113        was because its rules for how to advance for /g after matching an empty
1114        string at the end of a line did not allow for this case. They now check for
1115        it specially.
1117    20. pcretest is supposed to handle patterns and data of any length, by
1118        extending its buffers when necessary. It was getting this wrong when the
1119        buffer for a data line had to be extended.
1121    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1122        CRLF as a newline sequence.
1124    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1125        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1126        I have nevertheless tidied it up.
1128    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1130    24. Added a man page for pcre-config.
1133    Version 7.0 19-Dec-06
1134    ---------------------
1136     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1137        moving to gcc 4.1.1.
1139     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1140        sys/time.h, which is documented as needed for this function. It doesn't
1141        seem to matter on Linux, but it showed up on some releases of OS X.
1143     3. It seems that there are systems where bytes whose values are greater than
1144        127 match isprint() in the "C" locale. The "C" locale should be the
1145        default when a C program starts up. In most systems, only ASCII printing
1146        characters match isprint(). This difference caused the output from pcretest
1147        to vary, making some of the tests fail. I have changed pcretest so that:
1149        (a) When it is outputting text in the compiled version of a pattern, bytes
1150            other than 32-126 are always shown as hex escapes.
1152        (b) When it is outputting text that is a matched part of a subject string,
1153            it does the same, unless a different locale has been set for the match
1154            (using the /L modifier). In this case, it uses isprint() to decide.
1156     4. Fixed a major bug that caused incorrect computation of the amount of memory
1157        required for a compiled pattern when options that changed within the
1158        pattern affected the logic of the preliminary scan that determines the
1159        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1160        that the computed length was too small. The symptoms of this bug were
1161        either the PCRE error "internal error: code overflow" from pcre_compile(),
1162        or a glibc crash with a message such as "pcretest: free(): invalid next
1163        size (fast)". Examples of patterns that provoked this bug (shown in
1164        pcretest format) are:
1166          /(?-x: )/x
1167          /(?x)(?-x: \s*#\s*)/
1168          /((?i)[\x{c0}])/8
1169          /(?i:[\x{c0}])/8
1171        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1172        is now done differently.
1174     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1175        wrapper classes; (b) implement a new function in the C++ scanner that is
1176        more efficient than the old way of doing things because it avoids levels of
1177        recursion in the regex matching; (c) add a paragraph to the documentation
1178        for the FullMatch() function.
1180     6. The escape sequence \n was being treated as whatever was defined as
1181        "newline". Not only was this contrary to the documentation, which states
1182        that \n is character 10 (hex 0A), but it also went horribly wrong when
1183        "newline" was defined as CRLF. This has been fixed.
1185     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1186        was being set to -1 for the "end of line" case (supposedly a value that no
1187        character can have). Though this value is never used (the check for end of
1188        line is "zero bytes in current character"), it caused compiler complaints.
1189        I've changed it to 0xffffffff.
1191     8. In pcre_version.c, the version string was being built by a sequence of
1192        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1193        string (as it is for production releases) called a macro with an empty
1194        argument. The C standard says the result of this is undefined. The gcc
1195        compiler treats it as an empty string (which was what was wanted) but it is
1196        reported that Visual C gives an error. The source has been hacked around to
1197        avoid this problem.
1199     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1200        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1201        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1202        of them did).
1204    10. Originally, pcretest opened its input and output without "b"; then I was
1205        told that "b" was needed in some environments, so it was added for release
1206        5.0 to both the input and output. (It makes no difference on Unix-like
1207        systems.) Later I was told that it is wrong for the input on Windows. I've
1208        now abstracted the modes into two macros, to make it easier to fiddle with
1209        them, and removed "b" from the input mode under Windows.
1211    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1213    12. Added -help and --help to pcretest as an official way of being reminded
1214        of the options.
1216    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1217        and pcrecpp.cc because they annoy compilers at high warning levels.
1219    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1221    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1222        scripts are not C programs :-) and which was not noticed because it works
1223        on Linux.
1225    16. pcretest is supposed to handle any length of pattern and data line (as one
1226        line or as a continued sequence of lines) by extending its input buffer if
1227        necessary. This feature was broken for very long pattern lines, leading to
1228        a string of junk being passed to pcre_compile() if the pattern was longer
1229        than about 50K.
1231    17. I have done a major re-factoring of the way pcre_compile() computes the
1232        amount of memory needed for a compiled pattern. Previously, there was code
1233        that made a preliminary scan of the pattern in order to do this. That was
1234        OK when PCRE was new, but as the facilities have expanded, it has become
1235        harder and harder to keep it in step with the real compile phase, and there
1236        have been a number of bugs (see for example, 4 above). I have now found a
1237        cunning way of running the real compile function in a "fake" mode that
1238        enables it to compute how much memory it would need, while actually only
1239        ever using a few hundred bytes of working memory and without too many
1240        tests of the mode. This should make future maintenance and development
1241        easier. A side effect of this work is that the limit of 200 on the nesting
1242        depth of parentheses has been removed (though this was never a serious
1243        limitation, I suspect). However, there is a downside: pcre_compile() now
1244        runs more slowly than before (30% or more, depending on the pattern). I
1245        hope this isn't a big issue. There is no effect on runtime performance.
1247    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1248        newline (only possible for the last line of a file) and it was a
1249        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1251    19. Added additional timing features to pcretest. (1) The -tm option now times
1252        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1253        separate command line item, by a number that specifies the number of
1254        repeats to use when timing. The default is 50000; this gives better
1255        precision, but takes uncomfortably long for very large patterns.
1257    20. Extended pcre_study() to be more clever in cases where a branch of a
1258        subpattern has no definite first character. For example, (a*|b*)[cd] would
1259        previously give no result from pcre_study(). Now it recognizes that the
1260        first character must be a, b, c, or d.
1262    21. There was an incorrect error "recursive call could loop indefinitely" if
1263        a subpattern (or the entire pattern) that was being tested for matching an
1264        empty string contained only one non-empty item after a nested subpattern.
1265        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1266        incorrectly, because the \d was being skipped in the check.
1268    22. The pcretest program now has a new pattern option /B and a command line
1269        option -b, which is equivalent to adding /B to every pattern. This causes
1270        it to show the compiled bytecode, without the additional information that
1271        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1272        is the same as /B/I).
1274    23. A new optimization is now able automatically to treat some sequences such
1275        as a*b as a*+b. More specifically, if something simple (such as a character
1276        or a simple class like \d) has an unlimited quantifier, and is followed by
1277        something that cannot possibly match the quantified thing, the quantifier
1278        is automatically "possessified".
1280    24. A recursive reference to a subpattern whose number was greater than 39
1281        went wrong under certain circumstances in UTF-8 mode. This bug could also
1282        have affected the operation of pcre_study().
1284    25. Realized that a little bit of performance could be had by replacing
1285        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1287    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1289    27. Possessive quantifiers such as a++ were previously implemented by turning
1290        them into atomic groups such as ($>a+). Now they have their own opcodes,
1291        which improves performance. This includes the automatically created ones
1292        from 23 above.
1294    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1295        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1296        the first matched character to be a colon. This applied both to named and
1297        numbered groups.
1299    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1301    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1302        building PCRE on Windows easier, so I have included it in the distribution.
1304    31. There is now a check in pcretest against a ridiculously large number being
1305        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1306        loop, the loop is abandoned.
1308    32. Forward references to subpatterns in conditions such as (?(2)...) where
1309        subpattern 2 is defined later cause pcre_compile() to search forwards in
1310        the pattern for the relevant set of parentheses. This search went wrong
1311        when there were unescaped parentheses in a character class, parentheses
1312        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1314    33. "Subroutine" calls and backreferences were previously restricted to
1315        referencing subpatterns earlier in the regex. This restriction has now
1316        been removed.
1318    34. Added a number of extra features that are going to be in Perl 5.10. On the
1319        whole, these are just syntactic alternatives for features that PCRE had
1320        previously implemented using the Python syntax or my own invention. The
1321        other formats are all retained for compatibility.
1323        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1324            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1325            also .NET compatible.
1327        (b) A recursion or subroutine call to a named group can now be defined as
1328            (?&name) as well as (?P>name).
1330        (c) A backreference to a named group can now be defined as \k<name> or
1331            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1332            5.10, are also .NET compatible.
1334        (d) A conditional reference to a named group can now use the syntax
1335            (?(<name>) or (?('name') as well as (?(name).
1337        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1338            groups (named and numbered) that are never evaluated inline, but can be
1339            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1340            is always false. There may be only one alternative in such a group.
1342        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1343            as the simple (?(R). The condition is true only if the most recent
1344            recursion is that of the given number or name. It does not search out
1345            through the entire recursion stack.
1347        (g) The escape \gN or \g{N} has been added, where N is a positive or
1348            negative number, specifying an absolute or relative reference.
1350    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1351        some "unreachable code" warnings.
1353    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1354        things, this adds five new scripts.
1356    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1357        There were also incompatibilities regarding the handling of \Q..\E inside
1358        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1359        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1361    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1362        matches an empty string, and forcibly breaks the loop. There were bugs in
1363        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1364        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1365        separate and independent bugs (that affected different cases) have been
1366        fixed.
1368    39. Refactored the code to abolish the use of different opcodes for small
1369        capturing bracket numbers. This is a tidy that I avoided doing when I
1370        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1371        The new approach is not only tidier, it makes it possible to reduce the
1372        memory needed to fix the previous bug (38).
1374    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1375        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1376        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1377        mode.
1379    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1380        report.
1382    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1383        copy construction and assignment in the C++ wrapper.
1385    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1386        couple of bugs that could have given wrong results in the "--newline=crlf"
1387        case.
1389    44. Added a number of casts and did some reorganization of signed/unsigned int
1390        variables following suggestions from Dair Grant. Also renamed the variable
1391        "this" as "item" because it is a C++ keyword.
1393    45. Arranged for dftables to add
1395          #include "pcre_internal.h"
1397        to pcre_chartables.c because without it, gcc 4.x may remove the array
1398        definition from the final binary if PCRE is built into a static library and
1399        dead code stripping is activated.
1401    46. For an unanchored pattern, if a match attempt fails at the start of a
1402        newline sequence, and the newline setting is CRLF or ANY, and the next two
1403        characters are CRLF, advance by two characters instead of one.
1406    Version 6.7 04-Jul-06
1407    ---------------------
1409     1. In order to handle tests when input lines are enormously long, pcretest has
1410        been re-factored so that it automatically extends its buffers when
1411        necessary. The code is crude, but this _is_ just a test program. The
1412        default size has been increased from 32K to 50K.
1414     2. The code in pcre_study() was using the value of the re argument before
1415        testing it for NULL. (Of course, in any sensible call of the function, it
1416        won't be NULL.)
1418     3. The memmove() emulation function in pcre_internal.h, which is used on
1419        systems that lack both memmove() and bcopy() - that is, hardly ever -
1420        was missing a "static" storage class specifier.
1422     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1423        containing an extended class (one that cannot be represented by a bitmap
1424        because it contains high-valued characters or Unicode property items, e.g.
1425        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1426        pattern, but PCRE should not loop if you do not (it no longer does).
1427        [Detail: two cases were found: (a) a repeated subpattern containing an
1428        extended class; (b) a recursive reference to a subpattern that followed a
1429        previous extended class. It wasn't skipping over the extended class
1430        correctly when UTF-8 mode was not set.]
1432     5. A negated single-character class was not being recognized as fixed-length
1433        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1434        compile error "lookbehind assertion is not fixed length".
1436     6. The RunPerlTest auxiliary script was showing an unexpected difference
1437        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1438        write a Perl script that can interpret lines of an input file either as
1439        byte characters or as UTF-8, which is what "perltest" was being required to
1440        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1441        can't do is switch easily at run time between having the "use utf8;" pragma
1442        or not. In the end, I fudged it by using the RunPerlTest script to insert
1443        "use utf8;" explicitly for the UTF-8 tests.
1445     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1446        the end of the subject string, contrary to the documentation and to what
1447        Perl does. This was true of both matching functions. Now it matches only at
1448        the start of the subject and immediately after *internal* newlines.
1450     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1451        a pointer to an int instead of a pointer to an unsigned long int. This
1452        caused problems on 64-bit systems.
1454     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1455        instance of the 'standard' template library not being so standard".
1457    10. There was no check on the number of named subpatterns nor the maximum
1458        length of a subpattern name. The product of these values is used to compute
1459        the size of the memory block for a compiled pattern. By supplying a very
1460        long subpattern name and a large number of named subpatterns, the size
1461        computation could be caused to overflow. This is now prevented by limiting
1462        the length of names to 32 characters, and the number of named subpatterns
1463        to 10,000.
1465    11. Subpatterns that are repeated with specific counts have to be replicated in
1466        the compiled pattern. The size of memory for this was computed from the
1467        length of the subpattern and the repeat count. The latter is limited to
1468        65535, but there was no limit on the former, meaning that integer overflow
1469        could in principle occur. The compiled length of a repeated subpattern is
1470        now limited to 30,000 bytes in order to prevent this.
1472    12. Added the optional facility to have named substrings with the same name.
1474    13. Added the ability to use a named substring as a condition, using the
1475        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1476        are numbers (not recommended). Forward references are permitted.
1478    14. Added forward references in named backreferences (if you see what I mean).
1480    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1481        pattern could run off the end of the subject. For example, the pattern
1482        "(?s)(.{1,5})"8 did this with the subject "ab".
1484    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1485        PCRE_CASELESS was set when matching characters that were quantified with ?
1486        or *.
1488    17. A character class other than a single negated character that had a minimum
1489        but no maximum quantifier - for example [ab]{6,} - was not handled
1490        correctly by pce_dfa_exec(). It would match only one character.
1492    18. A valid (though odd) pattern that looked like a POSIX character
1493        class but used an invalid character after [ (for example [[,abc,]]) caused
1494        pcre_compile() to give the error "Failed: internal error: code overflow" or
1495        in some cases to crash with a glibc free() error. This could even happen if
1496        the pattern terminated after [[ but there just happened to be a sequence of
1497        letters, a binary zero, and a closing ] in the memory that followed.
1499    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1500        over the years. Originally (before any Unicode support), just the bottom 8
1501        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1502        output from "man perlunicode" includes this:
1504          The regular expression compiler produces polymorphic opcodes.  That
1505          is, the pattern adapts to the data and automatically switches to
1506          the Unicode character scheme when presented with Unicode data--or
1507          instead uses a traditional byte scheme when presented with byte
1508          data.
1510        Sadly, a wide octal escape does not cause a switch, and in a string with
1511        no other multibyte characters, these octal escapes are treated as before.
1512        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1513        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1514        Unicode string.
1516        I have not perpetrated such confusion in PCRE. Up till now, it took just
1517        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1518        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1519        translate to the appropriate multibyte character.
1521    29. Applied some refactoring to reduce the number of warnings from Microsoft
1522        and Borland compilers. This has included removing the fudge introduced
1523        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1524        a warning about an unused variable.
1526    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1527        characters since release 4.0, because Perl (from release 5.004) does not.
1528        [Or at least, is documented not to: some releases seem to be in conflict
1529        with the documentation.] However, when a pattern was studied with
1530        pcre_study() and all its branches started with \s, PCRE still included VT
1531        as a possible starting character. Of course, this did no harm; it just
1532        caused an unnecessary match attempt.
1534    22. Removed a now-redundant internal flag bit that recorded the fact that case
1535        dependency changed within the pattern. This was once needed for "required
1536        byte" processing, but is no longer used. This recovers a now-scarce options
1537        bit. Also moved the least significant internal flag bit to the most-
1538        significant bit of the word, which was not previously used (hangover from
1539        the days when it was an int rather than a uint) to free up another bit for
1540        the future.
1542    23. Added support for CRLF line endings as well as CR and LF. As well as the
1543        default being selectable at build time, it can now be changed at runtime
1544        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1545        specify that it is scanning data with non-default line endings.
1547    24. Changed the definition of CXXLINK to make it agree with the definition of
1548        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1550    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1551        recursions. This makes a big different to stack usage for some patterns.
1553    26. If a subpattern containing a named recursion or subroutine reference such
1554        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1555        the space required for the compiled pattern went wrong and gave too small a
1556        value. Depending on the environment, this could lead to "Failed: internal
1557        error: code overflow at offset 49" or "glibc detected double free or
1558        corruption" errors.
1560    27. Applied patches from Google (a) to support the new newline modes and (b) to
1561        advance over multibyte UTF-8 characters in GlobalReplace.
1563    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1564        difference for some implementation of PCRE in some Windows version.
1566    29. Added some extra testing facilities to pcretest:
1568        \q<number>   in a data line sets the "match limit" value
1569        \Q<number>   in a data line sets the "match recursion limt" value
1570        -S <number>  sets the stack size, where <number> is in megabytes
1572        The -S option isn't available for Windows.
1575    Version 6.6 06-Feb-06
1576    ---------------------
1578     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1579        in pcreposix.h. I have copied the definition from pcre.h.
1581     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1582        because pcre.h is no longer a built file.
1584     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1585        not normally included in the compiled code.
1588    Version 6.5 01-Feb-06
1589    ---------------------
1591     1. When using the partial match feature with pcre_dfa_exec(), it was not
1592        anchoring the second and subsequent partial matches at the new starting
1593        point. This could lead to incorrect results. For example, with the pattern
1594        /1234/, partially matching against "123" and then "a4" gave a match.
1596     2. Changes to pcregrep:
1598        (a) All non-match returns from pcre_exec() were being treated as failures
1599            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1600            error message is output. Some extra information is given for the
1601            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1602            probably the only errors that are likely to be caused by users (by
1603            specifying a regex that has nested indefinite repeats, for instance).
1604            If there are more than 20 of these errors, pcregrep is abandoned.
1606        (b) A binary zero was treated as data while matching, but terminated the
1607            output line if it was written out. This has been fixed: binary zeroes
1608            are now no different to any other data bytes.
1610        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1611            used to set a locale for matching. The --locale=xxxx long option has
1612            been added (no short equivalent) to specify a locale explicitly on the
1613            pcregrep command, overriding the environment variables.
1615        (d) When -B was used with -n, some line numbers in the output were one less
1616            than they should have been.
1618        (e) Added the -o (--only-matching) option.
1620        (f) If -A or -C was used with -c (count only), some lines of context were
1621            accidentally printed for the final match.
1623        (g) Added the -H (--with-filename) option.
1625        (h) The combination of options -rh failed to suppress file names for files
1626            that were found from directory arguments.
1628        (i) Added the -D (--devices) and -d (--directories) options.
1630        (j) Added the -F (--fixed-strings) option.
1632        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1634        (l) Added the --colo(u)r option.
1636        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1637            is not present by default.
1639     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1640        items such as (?R) or (?1), when the recursion could match a number of
1641        alternatives. If it matched one of the alternatives, but subsequently,
1642        outside the recursion, there was a failure, the code tried to back up into
1643        the recursion. However, because of the way PCRE is implemented, this is not
1644        possible, and the result was an incorrect result from the match.
1646        In order to prevent this happening, the specification of recursion has
1647        been changed so that all such subpatterns are automatically treated as
1648        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1650     4. I had overlooked the fact that, in some locales, there are characters for
1651        which isalpha() is true but neither isupper() nor islower() are true. In
1652        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1653        and ordfeminine) are like this. This affected the treatment of \w and \W
1654        when they appeared in character classes, but not when they appeared outside
1655        a character class. The bit map for "word" characters is now created
1656        separately from the results of isalnum() instead of just taking it from the
1657        upper, lower, and digit maps. (Plus the underscore character, of course.)
1659     5. The above bug also affected the handling of POSIX character classes such as
1660        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1661        permanent tables. Instead, the bit maps for such a class were previously
1662        created as the appropriate unions of the upper, lower, and digit bitmaps.
1663        Now they are created by subtraction from the [[:word:]] class, which has
1664        its own bitmap.
1666     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1667        It is created by subtracting the vertical space characters (\x09, \x0a,
1668        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1669        subtraction was done in the overall bitmap for a character class, meaning
1670        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1671        be recognized. This bug has been fixed.
1673     7. Patches from the folks at Google:
1675          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1676          real life, but is still worth protecting against".
1678          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1679          regular expressions".
1681          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1682          have it.
1684          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1685          "configure" and the latter not, in order to fix a problem somebody had
1686          with compiling the Arg class on HP-UX.
1688          (e) Improve the error-handling of the C++ wrapper a little bit.
1690          (f) New tests for checking recursion limiting.
1692     8. The pcre_memmove() function, which is used only if the environment does not
1693        have a standard memmove() function (and is therefore rarely compiled),
1694        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1695        returning a result (though PCRE never actually uses the result).
1697     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1698        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1699        returned instead of calling malloc() with an overflowing number that would
1700        most likely cause subsequent chaos.
1702    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1704    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1705        with this option is matched, the nmatch and pmatch options of regexec() are
1706        ignored.
1708    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1709        provided in case anyone wants to the the POSIX interface with UTF-8
1710        strings.
1712    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1713        C++ linking (needed for some HP-UX environments).
1715    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1716        (unused parameter) and in the pcre_printint() function (omitted "default"
1717        switch label when the default is to do nothing).
1719    15. Added some code to make it possible, when PCRE is compiled as a C++
1720        library, to replace subject pointers for pcre_exec() with a smart pointer
1721        class, thus making it possible to process discontinuous strings.
1723    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1724        much the same function. They were added by different people who were trying
1725        to make PCRE easy to compile on non-Unix systems. It has been suggested
1726        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1727        for compiling on Windows systems. I have therefore replaced it with
1728        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1729        defaults to "extern" for C or "extern C" for C++, which works fine on
1730        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1731        SCOPE with something explicit in config.h. In addition:
1733        (a) pcreposix.h still had just "extern" instead of either of these macros;
1734            I have replaced it with PCRE_DATA_SCOPE.
1736        (b) Functions such as _pcre_xclass(), which are internal to the library,
1737            but external in the C sense, all had PCRE_EXPORT in their definitions.
1738            This is apparently wrong for the Windows case, so I have removed it.
1739            (It makes no difference on Unix-like systems.)
1741    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1742        of recursive calls to match(). This is different to MATCH_LIMIT because
1743        that limits the total number of calls to match(), not all of which increase
1744        the depth of recursion. Limiting the recursion depth limits the amount of
1745        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1746        when PCRE is compiled, and changed at run time. A patch from Google adds
1747        this functionality to the C++ interface.
1749    18. Changes to the handling of Unicode character properties:
1751        (a) Updated the table to Unicode 4.1.0.
1753        (b) Recognize characters that are not in the table as "Cn" (undefined).
1755        (c) I revised the way the table is implemented to a much improved format
1756            which includes recognition of ranges. It now supports the ranges that
1757            are defined in UnicodeData.txt, and it also amalgamates other
1758            characters into ranges. This has reduced the number of entries in the
1759            table from around 16,000 to around 3,000, thus reducing its size
1760            considerably. I realized I did not need to use a tree structure after
1761            all - a binary chop search is just as efficient. Having reduced the
1762            number of entries, I extended their size from 6 bytes to 8 bytes to
1763            allow for more data.
1765        (d) Added support for Unicode script names via properties such as \p{Han}.
1767    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1768        matching that character.
1770    20. When matching a repeated Unicode property with a minimum greater than zero,
1771        (for example \pL{2,}), PCRE could look past the end of the subject if it
1772        reached it while seeking the minimum number of characters. This could
1773        happen only if some of the characters were more than one byte long, because
1774        there is a check for at least the minimum number of bytes.
1776    21. Refactored the implementation of \p and \P so as to be more general, to
1777        allow for more different types of property in future. This has changed the
1778        compiled form incompatibly. Anybody with saved compiled patterns that use
1779        \p or \P will have to recompile them.
1781    22. Added "Any" and "L&" to the supported property types.
1783    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1784        but give a compile time error if the value is greater than 0xff.
1786    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1787        accidentally not being installed or uninstalled.
1789    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1790        made were to insert the current release number. This seemed silly, because
1791        it made things harder for people building PCRE on systems that don't run
1792        "configure". I have turned pcre.h into a distributed file, no longer built
1793        by "configure", with the version identification directly included. There is
1794        no longer a pcre.h.in file.
1796        However, this change necessitated a change to the pcre-config script as
1797        well. It is built from pcre-config.in, and one of the substitutions was the
1798        release number. I have updated configure.ac so that ./configure now finds
1799        the release number by grepping pcre.h.
1801    26. Added the ability to run the tests under valgrind.
1804    Version 6.4 05-Sep-05
1805    ---------------------
1807     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1808        "--" to be printed when multiple files were scanned, even when none of the
1809        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1810        consider it to be a bug, and have restored the previous behaviour.
1812     2. A couple of code tidies to get rid of compiler warnings.
1814     3. The pcretest program used to cheat by referring to symbols in the library
1815        whose names begin with _pcre_. These are internal symbols that are not
1816        really supposed to be visible externally, and in some environments it is
1817        possible to suppress them. The cheating is now confined to including
1818        certain files from the library's source, which is a bit cleaner.
1820     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1821        file's purpose clearer.
1823     5. Reorganized pcre_ucp_findchar().
1826    Version 6.3 15-Aug-05
1827    ---------------------
1829     1. The file libpcre.pc.in did not have general read permission in the tarball.
1831     2. There were some problems when building without C++ support:
1833        (a) If C++ support was not built, "make install" and "make test" still
1834            tried to test it.
1836        (b) There were problems when the value of CXX was explicitly set. Some
1837            changes have been made to try to fix these, and ...
1839        (c) --disable-cpp can now be used to explicitly disable C++ support.
1841        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1842            backslash in a target when C++ was disabled. This confuses some
1843            versions of "make", apparently. Using an intermediate variable solves
1844            this. (Same for CPP_LOBJ.)
1846     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1847        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1848        necessary on certain architectures.
1850     4. Added a setting of -export-symbols-regex to the link command to remove
1851        those symbols that are exported in the C sense, but actually are local
1852        within the library, and not documented. Their names all begin with
1853        "_pcre_". This is not a perfect job, because (a) we have to except some
1854        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1855        available (and never for static libraries). I have made a note to try to
1856        find a way round (a) in the future.
1859    Version 6.2 01-Aug-05
1860    ---------------------
1862     1. There was no test for integer overflow of quantifier values. A construction
1863        such as {1111111111111111} would give undefined results. What is worse, if
1864        a minimum quantifier for a parenthesized subpattern overflowed and became
1865        negative, the calculation of the memory size went wrong. This could have
1866        led to memory overwriting.
1868     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1870     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1871        operating environments where this matters.
1873     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1874        PCRE options from within the C++ wrapper.
1876     5. Named capturing subpatterns were not being correctly counted when a pattern
1877        was compiled. This caused two problems: (a) If there were more than 100
1878        such subpatterns, the calculation of the memory needed for the whole
1879        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1880        back references of the form \12, where the number was greater than 9, were
1881        not recognized as back references, even though there were sufficient
1882        previous subpatterns.
1884     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1885        versions of gcc, e.g. 2.95.4.
1888    Version 6.1 21-Jun-05
1889    ---------------------
1891     1. There was one reference to the variable "posix" in pcretest.c that was not
1892        surrounded by "#if !defined NOPOSIX".
1894     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1895        the cross-check on the old pcre_info() function, for the benefit of the
1896        cut-down version of PCRE that is currently imported into Exim.
1898     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1899        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1900        patterns that start (?i) but I don't think that matters. The use of (?i) is
1901        just an example; this all applies to the other options as well.
1903     4. Since libtool seems to echo the compile commands it is issuing, the output
1904        from "make" can be reduced a bit by putting "@" in front of each libtool
1905        compile command.
1907     5. Patch from the folks at Google for configure.in to be a bit more thorough
1908        in checking for a suitable C++ installation before trying to compile the
1909        C++ stuff. This should fix a reported problem when a compiler was present,
1910        but no suitable headers.
1912     6. The man pages all had just "PCRE" as their title. I have changed them to
1913        be the relevant file name. I have also arranged that these names are
1914        retained in the file doc/pcre.txt, which is a concatenation in text format
1915        of all the man pages except the little individual ones for each function.
1917     7. The NON-UNIX-USE file had not been updated for the different set of source
1918        files that come with release 6. I also added a few comments about the C++
1919        wrapper.
1922    Version 6.0 07-Jun-05
1923    ---------------------
1925     1. Some minor internal re-organization to help with my DFA experiments.
1927     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1928        didn't matter for the library itself when fully configured, but did matter
1929        when compiling without UCP support, or within Exim, where the ucp files are
1930        not imported.
1932     3. Refactoring of the library code to split up the various functions into
1933        different source modules. The addition of the new DFA matching code (see
1934        below) to a single monolithic source would have made it really too
1935        unwieldy, quite apart from causing all the code to be include in a
1936        statically linked application, when only some functions are used. This is
1937        relevant even without the DFA addition now that patterns can be compiled in
1938        one application and matched in another.
1940        The downside of splitting up is that there have to be some external
1941        functions and data tables that are used internally in different modules of
1942        the library but which are not part of the API. These have all had their
1943        names changed to start with "_pcre_" so that they are unlikely to clash
1944        with other external names.
1946     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1947        a different (DFA) algorithm. Although it is slower than the original
1948        function, it does have some advantages for certain types of matching
1949        problem.
1951     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1952        including restarting after a partial match.
1954     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1955        defined when compiling for Windows was sent to me. I have put it into the
1956        code, though I have no means of testing or verifying it.
1958     7. Added the pcre_refcount() auxiliary function.
1960     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1961        match before or at the first newline in the subject string. In pcretest,
1962        the /f option on a pattern can be used to set this.
1964     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1965        would behave wrongly. This has been present in PCRE since release 4.0.
1967    10. A number of changes to the pcregrep command:
1969        (a) Refactored how -x works; insert ^(...)$ instead of setting
1970            PCRE_ANCHORED and checking the length, in preparation for adding
1971            something similar for -w.
1973        (b) Added the -w (match as a word) option.
1975        (c) Refactored the way lines are read and buffered so as to have more
1976            than one at a time available.
1978        (d) Implemented a pcregrep test script.
1980        (e) Added the -M (multiline match) option. This allows patterns to match
1981            over several lines of the subject. The buffering ensures that at least
1982            8K, or the rest of the document (whichever is the shorter) is available
1983            for matching (and similarly the previous 8K for lookbehind assertions).
1985        (f) Changed the --help output so that it now says
1987              -w, --word-regex(p)
1989            instead of two lines, one with "regex" and the other with "regexp"
1990            because that confused at least one person since the short forms are the
1991            same. (This required a bit of code, as the output is generated
1992            automatically from a table. It wasn't just a text change.)
1994        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1995            option but starts with a hyphen. Could be a pattern or a path name
1996            starting with a hyphen, for instance.
1998        (h) "-" can be given as a file name to represent stdin.
2000        (i) When file names are being printed, "(standard input)" is used for
2001            the standard input, for compatibility with GNU grep. Previously
2002            "<stdin>" was used.
2004        (j) The option --label=xxx can be used to supply a name to be used for
2005            stdin when file names are being printed. There is no short form.
2007        (k) Re-factored the options decoding logic because we are going to add
2008            two more options that take data. Such options can now be given in four
2009            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2011        (l) Added the -A, -B, and -C options for requesting that lines of context
2012            around matches be printed.
2014        (m) Added the -L option to print the names of files that do not contain
2015            any matching lines, that is, the complement of -l.
2017        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2018            continue to scan other files.
2020        (o) The -s option was incorrectly implemented. For compatibility with other
2021            greps, it now suppresses the error message for a non-existent or non-
2022            accessible file (but not the return code). There is a new option called
2023            -q that suppresses the output of matching lines, which was what -s was
2024            previously doing.
2026        (p) Added --include and --exclude options to specify files for inclusion
2027            and exclusion when recursing.
2029    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2030        Hopefully, it now does.
2032    12. Missing cast in pcre_study().
2034    13. Added an "uninstall" target to the makefile.
2036    14. Replaced "extern" in the function prototypes in Makefile.in with
2037        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2038        world, but is set differently for Windows.
2040    15. Added a second compiling function called pcre_compile2(). The only
2041        difference is that it has an extra argument, which is a pointer to an
2042        integer error code. When there is a compile-time failure, this is set
2043        non-zero, in addition to the error test pointer being set to point to an
2044        error message. The new argument may be NULL if no error number is required
2045        (but then you may as well call pcre_compile(), which is now just a
2046        wrapper). This facility is provided because some applications need a
2047        numeric error indication, but it has also enabled me to tidy up the way
2048        compile-time errors are handled in the POSIX wrapper.
2050    16. Added VPATH=.libs to the makefile; this should help when building with one
2051        prefix path and installing with another. (Or so I'm told by someone who
2052        knows more about this stuff than I do.)
2054    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2055        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2056        match everything, including newlines. This is not POSIX-compatible, but
2057        somebody wanted the feature. From pcretest it can be activated by using
2058        both the P and the s flags.
2060    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2062    19. libpcre.pc was being incorrectly installed as executable.
2064    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2065        it now also looks for '\r' so that it will work unmodified on Windows.
2067    21. Added Google's contributed C++ wrapper to the distribution.
2069    22. Added some untidy missing memory free() calls in pcretest, to keep
2070        Electric Fence happy when testing.
2074    Version 5.0 13-Sep-04
2075    ---------------------
2077     1. Internal change: literal characters are no longer packed up into items
2078        containing multiple characters in a single byte-string. Each character
2079        is now matched using a separate opcode. However, there may be more than one
2080        byte in the character in UTF-8 mode.
2082     2. The pcre_callout_block structure has two new fields: pattern_position and
2083        next_item_length. These contain the offset in the pattern to the next match
2084        item, and its length, respectively.
2086     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2087        insertion of callouts before each pattern item. Added the /C option to
2088        pcretest to make use of this.
2090     4. On the advice of a Windows user, the lines
2092          #if defined(_WIN32) || defined(WIN32)
2093          _setmode( _fileno( stdout ), 0x8000 );
2094          #endif  /* defined(_WIN32) || defined(WIN32) */
2096        have been added to the source of pcretest. This apparently does useful
2097        magic in relation to line terminators.
2099     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2100        for the benefit of those environments where the "b" makes a difference.
2102     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2103        to know about it. I have put a hack into configure.in that adds in code
2104        to set GCC=yes if CC=icc. This seems to end up at a point in the
2105        generated configure script that is early enough to affect the setting of
2106        compiler options, which is what is needed, but I have no means of testing
2107        whether it really works. (The user who reported this had patched the
2108        generated configure script, which of course I cannot do.)
2110        LATER: After change 22 below (new libtool files), the configure script
2111        seems to know about icc (and also ecc). Therefore, I have commented out
2112        this hack in configure.in.
2114     7. Added support for pkg-config (2 patches were sent in).
2116     8. Negated POSIX character classes that used a combination of internal tables
2117        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2118        [[:^ascii]]. Typically, they would match almost any characters. The other
2119        POSIX classes were not broken in this way.
2121     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2122        to find the match, as PCRE was deluded into thinking that the match had to
2123        start at the start point or following a newline. The same bug applied to
2124        patterns with negative forward assertions or any backward assertions
2125        preceding ".*" at the start, unless the pattern required a fixed first
2126        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2128    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2129        starting at the last subject character, bytes beyond the end of the subject
2130        string were read.
2132    11. Renamed the variable "class" as "classbits" to make life easier for C++
2133        users. (Previously there was a macro definition, but it apparently wasn't
2134        enough.)
2136    12. Added the new field "tables" to the extra data so that tables can be passed
2137        in at exec time, or the internal tables can be re-selected. This allows
2138        a compiled regex to be saved and re-used at a later time by a different
2139        program that might have everything at different addresses.
2141    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2142        -R library as well as a -L library.
2144    14. The debugging options of pcretest (-d on the command line or D on a
2145        pattern) showed incorrect output for anything following an extended class
2146        that contained multibyte characters and which was followed by a quantifier.
2148    15. Added optional support for general category Unicode character properties
2149        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2150        support. It adds about 90K to the size of the library. The meanings of the
2151        inbuilt class escapes such as \d and \s have NOT been changed.
2153    16. Updated pcredemo.c to include calls to free() to release the memory for the
2154        compiled pattern.
2156    17. The generated file chartables.c was being created in the source directory
2157        instead of in the building directory. This caused the build to fail if the
2158        source directory was different from the building directory, and was
2159        read-only.
2161    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2162        file. No doubt somebody will tell me if they don't make sense... Also added
2163        Dan Mooney's comments about building on OpenVMS.
2165    19. Added support for partial matching via the PCRE_PARTIAL option for
2166        pcre_exec() and the \P data escape in pcretest.
2168    20. Extended pcretest with 3 new pattern features:
2170        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2171              write the compiled pattern to the file whose name is "rest-of-line".
2172              This is a straight binary dump of the data, with the saved pointer to
2173              the character tables forced to be NULL. The study data, if any, is
2174              written too. After writing, pcretest reads a new pattern.
2176        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2177              compiled pattern from the given file. There must not be any
2178              occurrences of "<" in the file name (pretty unlikely); if there are,
2179              pcretest will instead treat the initial "<" as a pattern delimiter.
2180              After reading in the pattern, pcretest goes on to read data lines as
2181              usual.
2183        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2184              and 16-bit fields in a compiled pattern, to simulate a pattern that
2185              was compiled on a host of opposite endianness.
2187    21. The pcre-exec() function can now cope with patterns that were compiled on
2188        hosts of opposite endianness, with this restriction:
2190          As for any compiled expression that is saved and used later, the tables
2191          pointer field cannot be preserved; the extra_data field in the arguments
2192          to pcre_exec() should be used to pass in a tables address if a value
2193          other than the default internal tables were used at compile time.
2195    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2196        now diagnosed as an error. Previously, most of the time, a negative number
2197        would have been treated as zero, but if in addition "ovector" was passed as
2198        NULL, a crash could occur.
2200    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2201        new versions from the libtool 1.5 distribution (the last one is a copy of
2202        a file called libtool.m4). This seems to have fixed the need to patch
2203        "configure" to support Darwin 1.3 (which I used to do). However, I still
2204        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2205        workstation).
2207    24. Changed the PCRE licence to be the more standard "BSD" licence.
2210    Version 4.5 01-Dec-03
2211    ---------------------
2213     1. There has been some re-arrangement of the code for the match() function so
2214        that it can be compiled in a version that does not call itself recursively.
2215        Instead, it keeps those local variables that need separate instances for
2216        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2217        needs to "recurse". Keeping track of where control must go is done by means
2218        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2219        hide most of the details from the main code, and operates only if
2220        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2221        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2222        operating.
2224        To make it easier for callers to provide specially tailored get/free
2225        functions for this usage, two new functions, pcre_stack_malloc, and
2226        pcre_stack_free, are used. They are always called in strict stacking order,
2227        and the size of block requested is always the same.
2229        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2230        PCRE has been compiled to use the stack or the heap for recursion. The
2231        -C option of pcretest uses this to show which version is compiled.
2233        A new data escape \S, is added to pcretest; it causes the amounts of store
2234        obtained and freed by both kinds of malloc/free at match time to be added
2235        to the output.
2237     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2238        what's available on my current Linux desktop machine.
2240     3. When matching a UTF-8 string, the test for a valid string at the start has
2241        been extended. If start_offset is not zero, PCRE now checks that it points
2242        to a byte that is the start of a UTF-8 character. If not, it returns
2243        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2244        this is necessary because there may be backward assertions in the pattern.
2245        When matching the same subject several times, it may save resources to use
2246        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2248     4. The code for checking the validity of UTF-8 strings has been tightened so
2249        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2250        containing "overlong sequences".
2252     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2253        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2254        should have been "&", but it just so happened that all the cases this let
2255        through by mistake were picked up later in the function.
2257     6. I had used a variable called "isblank" - this is a C99 function, causing
2258        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2260     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2261        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2262        so the version is shown; (c) stop "make test" echoing "./RunTest".
2264     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2266     9. The prototype for memmove() for systems that don't have it was using
2267        size_t, but the inclusion of the header that defines size_t was later. I've
2268        moved the #includes for the C headers earlier to avoid this.
2270    10. Added some adjustments to the code to make it easier to compiler on certain
2271        special systems:
2273          (a) Some "const" qualifiers were missing.
2274          (b) Added the macro EXPORT before all exported functions; by default this
2275              is defined to be empty.
2276          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2277              that it reads its output file name as an argument instead of writing
2278              to the standard output and assuming this can be redirected.
2280    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2281        class containing characters with values greater than 255, PCRE compilation
2282        went into a loop.
2284    12. A recursive reference to a subpattern that was within another subpattern
2285        that had a minimum quantifier of zero caused PCRE to crash. For example,
2286        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2287        recursion. If the recursively-called subpattern itself had a zero repeat,
2288        that was OK.
2290    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2291        buffer into which it was copied (for escape processing) was still set at
2292        1024, so long lines caused crashes.
2294    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2295        "internal error: code overflow...". This applied to any character class
2296        that was followed by a possessive quantifier.
2298    15. Modified the Makefile to add libpcre.la as a prerequisite for
2299        libpcreposix.la because I was told this is needed for a parallel build to
2300        work.
2302    16. If a pattern that contained .* following optional items at the start was
2303        studied, the wrong optimizing data was generated, leading to matching
2304        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2305        matching string must start with a or b or c. The correct conclusion for
2306        this pattern is that a match can start with any character.
2309    Version 4.4 13-Aug-03
2310    ---------------------
2312     1. In UTF-8 mode, a character class containing characters with values between
2313        127 and 255 was not handled correctly if the compiled pattern was studied.
2314        In fixing this, I have also improved the studying algorithm for such
2315        classes (slightly).
2317     2. Three internal functions had redundant arguments passed to them. Removal
2318        might give a very teeny performance improvement.
2320     3. Documentation bug: the value of the capture_top field in a callout is *one
2321        more than* the number of the hightest numbered captured substring.
2323     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2324        in incorrectly linking with a previously installed version. They now link
2325        explicitly with libpcre.la.
2327     5. configure.in no longer needs to recognize Cygwin specially.
2329     6. A problem in pcre.in for Windows platforms is fixed.
2331     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2332        pcretest, it used to include the size of the study block as part of its
2333        output. Unfortunately, the structure contains a field that has a different
2334        size on different hardware architectures. This meant that the tests that
2335        showed this size failed. As the block is currently always of a fixed size,
2336        this information isn't actually particularly useful in pcretest output, so
2337        I have just removed it.
2339     8. Three pre-processor statements accidentally did not start in column 1.
2340        Sadly, there are *still* compilers around that complain, even though
2341        standard C has not required this for well over a decade. Sigh.
2343     9. In pcretest, the code for checking callouts passed small integers in the
2344        callout_data field, which is a void * field. However, some picky compilers
2345        complained about the casts involved for this on 64-bit systems. Now
2346        pcretest passes the address of the small integer instead, which should get
2347        rid of the warnings.
2349    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2350        both compile and run time, and gives an error if an invalid UTF-8 sequence
2351        is found. There is a option for disabling this check in cases where the
2352        string is known to be correct and/or the maximum performance is wanted.
2354    11. In response to a bug report, I changed one line in Makefile.in from
2356            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2357        to
2358            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2360        to look similar to other lines, but I have no way of telling whether this
2361        is the right thing to do, as I do not use Windows. No doubt I'll get told
2362        if it's wrong...
2365    Version 4.3 21-May-03
2366    ---------------------
2368    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2369       Makefile.
2371    2. Some refactoring to improve the quality of the code:
2373       (i)   The utf8_table... variables are now declared "const".
2375       (ii)  The code for \cx, which used the "case flipping" table to upper case
2376             lower case letters, now just substracts 32. This is ASCII-specific,
2377             but the whole concept of \cx is ASCII-specific, so it seems
2378             reasonable.
2380       (iii) PCRE was using its character types table to recognize decimal and
2381             hexadecimal digits in the pattern. This is silly, because it handles
2382             only 0-9, a-f, and A-F, but the character types table is locale-
2383             specific, which means strange things might happen. A private
2384             table is now used for this - though it costs 256 bytes, a table is
2385             much faster than multiple explicit tests. Of course, the standard
2386             character types table is still used for matching digits in subject
2387             strings against \d.
2389       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2390             ending in _t are). So I've renamed it as ESC_tee.
2392    3. The first argument for regexec() in the POSIX wrapper should have been
2393       defined as "const".
2395    4. Changed pcretest to use malloc() for its buffers so that they can be
2396       Electric Fenced for debugging.
2398    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2399       to read one or more bytes before the start of the subject string. Often this
2400       had no effect on PCRE's behaviour, but in some circumstances it could
2401       provoke a segmentation fault.
2403    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2404       to try to read one or more bytes before the start of the subject string.
2406    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2407       UTF-8 support could misbehave in various ways if the subject string
2408       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2409       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2410       back over UTF-8 characters.)
2413    Version 4.2 14-Apr-03
2414    ---------------------
2416    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2418    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2419         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2420         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2421         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2422         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2423           and BUILD_EXEEXT
2424         Note: automatic setting of the BUILD variables is not yet working
2425         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2426           compile-time but not at link-time
2427         [LINK]: use for linking executables only
2428         make different versions for Windows and non-Windows
2429         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2430           libraries
2431         [LINK_FOR_BUILD]: new variable
2432         [OBJEXT]: use throughout
2433         [EXEEXT]: use throughout
2434         <winshared>: new target
2435         <wininstall>: new target
2436         <dftables.o>: use native compiler
2437         <dftables>: use native linker
2438         <install>: handle Windows platform correctly
2439         <clean>: ditto
2440         <check>: ditto
2441         copy DLL to top builddir before testing
2443       As part of these changes, -no-undefined was removed again. This was reported
2444       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2445       in any case.
2447    3. Some tidies to get rid of compiler warnings:
2449       . In the match_data structure, match_limit was an unsigned long int, whereas
2450         match_call_count was an int. I've made them both unsigned long ints.
2452       . In pcretest the fact that a const uschar * doesn't automatically cast to
2453         a void * provoked a warning.
2455       . Turning on some more compiler warnings threw up some "shadow" variables
2456         and a few more missing casts.
2458    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2459       option, a class that contained a single character with a value between 128
2460       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2462    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2463       option, a class that contained several characters, but with at least one
2464       whose value was between 128 and 255 caused PCRE to crash.
2467    Version 4.1 12-Mar-03
2468    ---------------------
2470    1. Compiling with gcc -pedantic found a couple of places where casts were
2471    needed, and a string in dftables.c that was longer than standard compilers are
2472    required to support.
2474    2. Compiling with Sun's compiler found a few more places where the code could
2475    be tidied up in order to avoid warnings.
2477    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2478    first of these names is deprecated in the latest Autoconf in favour of the name
2479    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2480    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2481    analogy I have changed it to CFLAGS_FOR_BUILD.
2483    4. Added -no-undefined to the linking command in the Makefile, because this is
2484    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2485    linking step for the pcreposix library.
2487    5. PCRE was failing to diagnose the case of two named groups with the same
2488    name.
2490    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2491    literal character that is needed in the subject for a match, and scans along to
2492    ensure that it is present before embarking on the full matching process. This
2493    saves time in cases of nested unlimited repeats that are never going to match.
2494    Problem: the scan can take a lot of time if the subject is very long (e.g.
2495    megabytes), thus penalizing straightforward matches. It is now done only if the
2496    amount of subject to be scanned is less than 1000 bytes.
2498    7. A lesser problem with the same optimization is that it was recording the
2499    first character of an anchored pattern as "needed", thus provoking a search
2500    right along the subject, even when the first match of the pattern was going to
2501    fail. The "needed" character is now not set for anchored patterns, unless it
2502    follows something in the pattern that is of non-fixed length. Thus, it still
2503    fulfils its original purpose of finding quick non-matches in cases of nested
2504    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2507    Version 4.0 17-Feb-03
2508    ---------------------
2510    1. If a comment in an extended regex that started immediately after a meta-item
2511    extended to the end of string, PCRE compiled incorrect data. This could lead to
2512    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2514    2. Moved to autoconf 2.53 and libtool 1.4.2.
2516    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2517    the special perltest8 script is no longer needed - all the tests can be run
2518    from a single perltest script.
2520    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2521    by \s. It has now been removed in PCRE. This means it isn't recognized as
2522    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2523    class [:space:] *does* include VT, thereby creating a mess.
2525    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2526    space and tab.
2528    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2529    its new features into the main test script, reducing the number of scripts.
2531    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2532    were backward compatible, and made the (?i) apply to the whole pattern, as if
2533    /i were given. Now it behaves more logically, and applies the option setting
2534    only to what follows. PCRE has been changed to follow suit. However, if it
2535    finds options settings right at the start of the pattern, it extracts them into
2536    the global options, as before. Thus, they show up in the info data.
2538    8. Added support for the \Q...\E escape sequence. Characters in between are
2539    treated as literals. This is slightly different from Perl in that $ and @ are
2540    also handled as literals inside the quotes. In Perl, they will cause variable
2541    interpolation. Note the following examples:
2543        Pattern            PCRE matches      Perl matches
2545        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2546        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2547        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2549    For compatibility with Perl, \Q...\E sequences are recognized inside character
2550    classes as well as outside them.
2552    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2553    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2554    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2555    signed/unsigned warnings.
2557    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2558    option for pcretest, so I've replaced it by a simple function that does just
2559    that job.
2561    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2562    "pcregrep -".
2564    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2565    Java package. This provides some syntactic sugar for simple cases of what my
2566    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2567    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2568    item, you can use this simplified notation. Note that only makes sense with
2569    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2570    greediness, whatever the setting of the PCRE_UNGREEDY option.
2572    13. A change of greediness default within a pattern was not taking effect at
2573    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2574    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2575    was abstracted outside.
2577    14. PCRE now supports the \G assertion. It is true when the current matching
2578    position is at the start point of the match. This differs from \A when the
2579    starting offset is non-zero. Used with the /g option of pcretest (or similar
2580    code), it works in the same way as it does for Perl's /g option. If all
2581    alternatives of a regex begin with \G, the expression is anchored to the start
2582    match position, and the "anchored" flag is set in the compiled expression.
2584    15. Some bugs concerning the handling of certain option changes within patterns
2585    have been fixed. These applied to options other than (?ims). For example,
2586    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2587    been the other way round. Some of this was related to change 7 above.
2589    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2590    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2591    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2592    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2594    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2595    mode. Unlike ".", it always matches newline, whatever the setting of
2596    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2597    assertions. Perl allows it, but it doesn't (in general) work because it can't
2598    calculate the length of the lookbehind. At least, that's the case for Perl
2599    5.8.0 - I've been told they are going to document that it doesn't work in
2600    future.
2602    18. Added an error diagnosis for escapes that PCRE does not support: these are
2603    \L, \l, \N, \P, \p, \U, \u, and \X.
2605    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2606    reading past the end of the pattern in cases such as /[abcd/.
2608    20. PCRE was getting more memory than necessary for patterns with classes that
2609    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2611    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2612    compiling PCRE for use with Virtual Pascal.
2614    22. Small fix to the Makefile to make it work properly if the build is done
2615    outside the source tree.
2617    23. Added a new extension: a condition to go with recursion. If a conditional
2618    subpattern starts with (?(R) the "true" branch is used if recursion has
2619    happened, whereas the "false" branch is used only at the top level.
2621    24. When there was a very long string of literal characters (over 255 bytes
2622    without UTF support, over 250 bytes with UTF support), the computation of how
2623    much memory was required could be incorrect, leading to segfaults or other
2624    strange effects.
2626    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2627    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2628    there was a subsequent back reference to those brackets. This meant that, for
2629    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2630    possible to check for precisely this case. All we can do is abandon the
2631    optimization if .* occurs inside capturing brackets when there are any back
2632    references whatsoever. (See below for a better fix that came later.)
2634    26. The handling of the optimization for finding the first character of a
2635    non-anchored pattern, and for finding a character that is required later in the
2636    match were failing in some cases. This didn't break the matching; it just
2637    failed to optimize when it could. The way this is done has been re-implemented.
2639    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2641    28. Added a new feature that provides some of the functionality that Perl
2642    provides with (?{...}). The facility is termed a "callout". The way it is done
2643    in PCRE is for the caller to provide an optional function, by setting
2644    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2645    global variable. By default it is unset, which disables all calling out. To get
2646    the function called, the regex must include (?C) at appropriate points. This
2647    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2648    This provides a means of identifying different callout points. When PCRE
2649    reaches such a point in the regex, if pcre_callout has been set, the external
2650    function is called. It is provided with data in a structure called
2651    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2652    matching continues; if it returns a non-zero value, the match at the current
2653    point fails. However, backtracking will occur if possible. [This was changed
2654    later and other features added - see item 49 below.]
2656    29. pcretest is upgraded to test the callout functionality. It provides a
2657    callout function that displays information. By default, it shows the start of
2658    the match and the current position in the text. There are some new data escapes
2659    to vary what happens:
2661        \C+         in addition, show current contents of captured substrings
2662        \C-         do not supply a callout function
2663        \C!n        return 1 when callout number n is reached
2664        \C!n!m      return 1 when callout number n is reached for the mth time
2666    30. If pcregrep was called with the -l option and just a single file name, it
2667    output "<stdin>" if a match was found, instead of the file name.
2669    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2670    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2671    pcre_exec(). This saves a malloc/free per call. The default value of
2672    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2673    when configuring.
2675    32. The default maximum size of a compiled pattern is 64K. There have been a
2676    few cases of people hitting this limit. The code now uses macros to handle the
2677    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2678    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2679    configuring. Tests 2 and 5 work only with 2-byte links because they output
2680    debugging information about compiled patterns.
2682    33. Internal code re-arrangements:
2684    (a) Moved the debugging function for printing out a compiled regex into
2685        its own source file (printint.c) and used #include to pull it into
2686        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2687        separate copies.
2689    (b) Defined the list of op-code names for debugging as a macro in
2690        internal.h so that it is next to the definition of the opcodes.
2692    (c) Defined a table of op-code lengths for simpler skipping along compiled
2693        code. This is again a macro in internal.h so that it is next to the
2694        definition of the opcodes.
2696    34. Added support for recursive calls to individual subpatterns, along the
2697    lines of Robin Houston's patch (but implemented somewhat differently).
2699    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2700    allow it to read and process whole directories in Win32. This code was
2701    contributed by Lionel Fourquaux; it has not been tested by me.
2703    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2704    used to name a group. Names consist of alphanumerics and underscores, and must
2705    be unique. Back references use the syntax (?P=name) and recursive calls use
2706    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2707    numbers. The function pcre_fullinfo() can be used after compilation to extract
2708    a name/number map. There are three relevant calls:
2710      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2711      PCRE_INFO_NAMECOUNT            yields the number of entries
2712      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2714    The map is a vector of fixed-size entries. The size of each entry depends on
2715    the length of the longest name used. The first two bytes of each entry are the
2716    group number, most significant byte first. There follows the corresponding
2717    name, zero terminated. The names are in alphabetical order.
2719    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2720    case instead of 255. Making it the same both with and without UTF-8 support
2721    means that the same test output works with both.
2723    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2724    calling malloc() with a zero argument.
2726    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2727    optimization. I've improved things by keeping a bitmap of backreferences with
2728    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2729    fact referenced, the optimization can be applied. It is unlikely that a
2730    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2731    the match to follow \n) will appear inside brackets with a number greater than
2732    31, but if it does, any back reference > 31 suppresses the optimization.
2734    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2735    of disabling numbered capturing parentheses. Any opening parenthesis that is
2736    not followed by ? behaves as if it were followed by ?: but named parentheses
2737    can still be used for capturing (and they will acquire numbers in the usual
2738    way).
2740    41. Redesigned the return codes from the match() function into yes/no/error so
2741    that errors can be passed back from deep inside the nested calls. A malloc
2742    failure while inside a recursive subpattern call now causes the
2743    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2745    42. It is now possible to set a limit on the number of times the match()
2746    function is called in a call to pcre_exec(). This facility makes it possible to
2747    limit the amount of recursion and backtracking, though not in a directly
2748    obvious way, because the match() function is used in a number of different
2749    circumstances. The count starts from zero for each position in the subject
2750    string (for non-anchored patterns). The default limit is, for compatibility, a
2751    large number, namely 10 000 000. You can change this in two ways:
2753    (a) When configuring PCRE before making, you can use --with-match-limit=n
2754        to set a default value for the compiled library.
2756    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2757        a different value is set. See 45 below.
2759    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2761    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2762    of things that can be changed at compile time. The first argument specifies
2763    what is wanted and the second points to where the information is to be placed.
2764    The current list of available information is:
2766      PCRE_CONFIG_UTF8
2768    The output is an integer that is set to one if UTF-8 support is available;
2769    otherwise it is set to zero.
2773    The output is an integer that it set to the value of the code that is used for
2774    newline. It is either LF (10) or CR (13).
2778    The output is an integer that contains the number of bytes used for internal
2779    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2783    The output is an integer that contains the threshold above which the POSIX
2784    interface uses malloc() for output vectors. See item 31 above.
2788    The output is an unsigned integer that contains the default limit of the number
2789    of match() calls in a pcre_exec() execution. See 42 above.
2791    44. pcretest has been upgraded by the addition of the -C option. This causes it
2792    to extract all the available output from the new pcre_config() function, and to
2793    output it. The program then exits immediately.
2795    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2796    order to support additional features. One way would have been to define
2797    pcre_exec2() (for example) with extra arguments, but this would not have been
2798    extensible, and would also have required all calls to the original function to
2799    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2800    is used for passing in "extra" data from pcre_study().
2802    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2803    contains the following fields:
2805      flags         a bitmap indicating which of the following fields are set
2806      study_data    opaque data from pcre_study()
2807      match_limit   a way of specifying a limit on match() calls for a specific
2808                      call to pcre_exec()
2809      callout_data  data for callouts (see 49 below)
2811    The flag bits are also defined in pcre.h, and are
2817    The pcre_study() function now returns one of these new pcre_extra blocks, with
2818    the actual study data pointed to by the study_data field, and the
2819    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2820    before. That is, this change is entirely upwards-compatible and requires no
2821    change to existing code.
2823    If you want to pass in additional data to pcre_exec(), you can either place it
2824    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2825    block.
2827    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2828    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2829    times with different match limits, until it finds the minimum value needed for
2830    pcre_exec() to complete. The value is then output. This can be instructive; for
2831    most simple matches the number is quite small, but for pathological cases it
2832    gets very large very quickly.
2834    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2835    returns the size of the data block pointed to by the study_data field in a
2836    pcre_extra block, that is, the value that was passed as the argument to
2837    pcre_malloc() when PCRE was getting memory in which to place the information
2838    created by pcre_study(). The fourth argument should point to a size_t variable.
2839    pcretest has been extended so that this information is shown after a successful
2840    pcre_study() call when information about the compiled regex is being displayed.
2842    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2843    because what follows is always an absolute path. (Later: it turns out that this
2844    is more than cosmetic for MinGW, because it doesn't like empty path
2845    components.)
2847    49. Some changes have been made to the callout feature (see 28 above):
2849    (i)  A callout function now has three choices for what it returns:
2851           0  =>  success, carry on matching
2852         > 0  =>  failure at this point, but backtrack if possible
2853         < 0  =>  serious error, return this value from pcre_exec()
2855         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2856         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2857         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2858         use by callout functions. It will never be used by PCRE itself.
2860    (ii) The pcre_extra structure (see 45 above) has a void * field called
2861         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2862         pcre_callout_block structure has a field of the same name. The contents of
2863         the field passed in the pcre_extra structure are passed to the callout
2864         function in the corresponding field in the callout block. This makes it
2865         easier to use the same callout-containing regex from multiple threads. For
2866         testing, the pcretest program has a new data escape
2868           \C*n        pass the number n (may be negative) as callout_data
2870         If the callout function in pcretest receives a non-zero value as
2871         callout_data, it returns that value.
2873    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2874    there were some redundant $(CFLAGS) in commands that are now specified as
2875    $(LINK), which already includes $(CFLAGS).
2877    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2878    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2879    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2880    one-byte characters throughout. Note that case-insensitive matching applies
2881    only to characters whose values are less than 256. PCRE doesn't support the
2882    notion of cases for higher-valued characters.
2884    (i)   A character class whose characters are all within 0-255 is handled as
2885          a bit map, and the map is inverted for negative classes. Previously, a
2886          character > 255 always failed to match such a class; however it should
2887          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2889    (ii)  A negated character class with a single character < 255 is coded as
2890          "not this character" (OP_NOT). This wasn't working properly when the test
2891          character was multibyte, either singly or repeated.
2893    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2894          mode, for example: \x{100}{2,3}.
2896    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2897          singly or repeated) now correctly test multibyte characters. However,
2898          PCRE doesn't recognize any characters with values greater than 255 as
2899          digits, spaces, or word characters. Such characters always match \D, \S,
2900          and \W, and never match \d, \s, or \w.
2902    (v)   Classes may now contain characters and character ranges with values
2903          greater than 255. For example: [ab\x{100}-\x{400}].
2905    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2906          PCRE in UTF-8 mode.
2908    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2909    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2910    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2911    value.)
2913    53. The single man page has become too large. I have therefore split it up into
2914    a number of separate man pages. These also give rise to individual HTML pages;
2915    these are now put in a separate directory, and there is an index.html page that
2916    lists them all. Some hyperlinking between the pages has been installed.
2918    54. Added convenience functions for handling named capturing parentheses.
2920    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2921    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2922    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2923    are faulted.
2925    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2926    calling configure. These values are used when compiling the dftables.c program
2927    which is run to generate the source of the default character tables. They
2928    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2929    you will need to set these values.
2931    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2934    Version 3.9 02-Jan-02
2935    ---------------------
2937    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2939    2. If --disable-static was given, the building process failed when trying to
2940    build pcretest and pcregrep. (For some reason it was using libtool to compile
2941    them, which is not right, as they aren't part of the library.)
2944    Version 3.8 18-Dec-01
2945    ---------------------
2947    1. The experimental UTF-8 code was completely screwed up. It was packing the
2948    bytes in the wrong order. How dumb can you get?
2951  Version 3.7 29-Oct-01  Version 3.7 29-Oct-01
2952  ---------------------  ---------------------
# Line 8  Version 3.7 29-Oct-01 Line 2955  Version 3.7 29-Oct-01
2955  This caused pcretest, when used on the test data, to segfault. Unfortunately,  This caused pcretest, when used on the test data, to segfault. Unfortunately,
2956  this didn't happen under Solaris 8, where I normally test things.  this didn't happen under Solaris 8, where I normally test things.
2958    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2959    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2960    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2961    this fix an hour or so after the initial 3.7 release.)
2964  Version 3.6 23-Oct-01  Version 3.6 23-Oct-01
2965  ---------------------  ---------------------

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