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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 457 by ph10, Sat Oct 3 16:24:08 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.00 ??-???-??
5    ----------------------
7    1.  The table for translating pcre_compile() error codes into POSIX error codes
8        was out-of-date, and there was no check on the pcre_compile() error code
9        being within the table. This could lead to an OK return being given in
10        error.
12    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
13        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14        in a Windows environment.
16    3.  The pcregrep --count option prints the count for each file even when it is
17        zero, as does GNU grep. However, pcregrep was also printing all files when
18        --files-with-matches was added. Now, when both options are given, it prints
19        counts only for those files that have at least one match. (GNU grep just
20        prints the file name in this circumstance, but including the count seems
21        more useful - otherwise, why use --count?) Also ensured that the
22        combination -clh just lists non-zero counts, with no names.
24    4.  The long form of the pcregrep -F option was incorrectly implemented as
25        --fixed_strings instead of --fixed-strings. This is an incompatible change,
26        but it seems right to fix it, and I didn't think it was worth preserving
27        the old behaviour.
29    5.  The command line items --regex=pattern and --regexp=pattern were not
30        recognized by pcregrep, which required --regex pattern or --regexp pattern
31        (with a space rather than an '='). The man page documented the '=' forms,
32        which are compatible with GNU grep; these now work.
34    6.  No libpcreposix.pc file was created for pkg-config; there was just
35        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
37    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
38        when UCP support is not needed, by modifying the Python script that
39        generates it from Unicode data files. This should not matter if the module
40        is correctly used as a library, but I received one complaint about 50K of
41        unwanted data. My guess is that the person linked everything into his
42        program rather than using a library. Anyway, it does no harm.
44    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
45        was a minimum greater than 1 for a wide character in a possessive
46        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
47        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
48        character. Chaos in the form of incorrect output or a compiling loop could
49        result.
51    9.  The restrictions on what a pattern can contain when partial matching is
52        requested for pcre_exec() have been removed. All patterns can now be
53        partially matched by this function. In addition, if there are at least two
54        slots in the offset vector, the offset of the earliest inspected character
55        for the match and the offset of the end of the subject are set in them when
56        PCRE_ERROR_PARTIAL is returned.
58    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
59        synonymous with PCRE_PARTIAL, for backwards compatibility, and
60        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
61        and may be more useful for multi-segment matching, especially with
62        pcre_exec().
64    11. Partial matching with pcre_exec() is now more intuitive. A partial match
65        used to be given if ever the end of the subject was reached; now it is
66        given only if matching could not proceed because another character was
67        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
68        string "Z", which now yields "no match" instead of "partial match". In the
69        case of pcre_dfa_exec(), "no match" is given if every matching path for the
70        final character ended with (*FAIL).
72    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
73        if the pattern had a "must contain" character that was already found in the
74        earlier partial match, unless partial matching was again requested. For
75        example, with the pattern /dog.(body)?/, the "must contain" character is
76        "g". If the first part-match was for the string "dog", restarting with
77        "sbody" failed. This bug has been fixed.
79    13. The string returned by pcre_dfa_exec() after a partial match has been
80        changed so that it starts at the first inspected character rather than the
81        first character of the match. This makes a difference only if the pattern
82        starts with a lookbehind assertion or \b or \B (\K is not supported by
83        pcre_dfa_exec()). It's an incompatible change, but it makes the two
84        matching functions compatible, and I think it's the right thing to do.
86    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
87        so that the demonstration program is easily available in environments where
88        PCRE has not been installed from source.
90    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
91        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
92        library.
94    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
95        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
96        is not the first non-POSIX option to be added. Clearly some people find
97        these options useful.
99    17. If a caller to the POSIX matching function regexec() passes a non-zero
100        value for nmatch with a NULL value for pmatch, the value of
101        nmatch is forced to zero.
103    18. RunGrepTest did not have a test for the availability of the -u option of
104        the diff command, as RunTest does. It now checks in the same way as
105        RunTest, and also checks for the -b option.
107    19. If an odd number of negated classes containing just a single character
108        interposed, within parentheses, between a forward reference to a named
109        subpattern and the definition of the subpattern, compilation crashed with
110        an internal error, complaining that it could not find the referenced
111        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
112        [The bug was that it was starting one character too far in when skipping
113        over the character class, thus treating the ] as data rather than
114        terminating the class. This meant it could skip too much.]
116    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
117        /g option in pcretest when the pattern contains \K, which makes it possible
118        to have an empty string match not at the start, even when the pattern is
119        anchored. Updated pcretest and pcredemo to use this option.
121    21. If the maximum number of capturing subpatterns in a recursion was greater
122        than the maximum at the outer level, the higher number was returned, but
123        with unset values at the outer level. The correct (outer level) value is
124        now given.
126    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
127        PCRE did not set those parentheses (unlike Perl). I have now found a way to
128        make it do so. The string so far is captured, making this feature
129        compatible with Perl.
131    23. The tests have been re-organized, adding tests 11 and 12, to make it
132        possible to check the Perl 5.10 features against Perl 5.10.
134    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
135        pattern matches a fixed length string. PCRE did not allow this; now it
136        does. Neither allows recursion.
138    25. I finally figured out how to implement a request to provide the minimum
139        length of subject string that was needed in order to match a given pattern.
140        (It was back references and recursion that I had previously got hung up
141        on.) This code has now been added to pcre_study(); it finds a lower bound
142        to the length of subject needed. It is not necessarily the greatest lower
143        bound, but using it to avoid searching strings that are too short does give
144        some useful speed-ups. The value is available to calling programs via
145        pcre_fullinfo().
147    26. While implementing 25, I discovered to my embarrassment that pcretest had
148        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
149        study optimizations had never been tested with that matching function.
150        Oops. What is worse, even when it was passed study data, there was a bug in
151        pcre_dfa_exec() that meant it never actually used it. Double oops. There
152        were also very few tests of studied patterns with pcre_dfa_exec().
154    27. If (?| is used to create subpatterns with duplicate numbers, they are now
155        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
156        on the other side of the coin, they are no longer allowed to have different
157        names, because these cannot be distinguished in PCRE, and this has caused
158        confusion. (This is a difference from Perl.)
161    Version 7.9 11-Apr-09
162    ---------------------
164    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
165        (pcretest), all targets were linked against these libraries. This included
166        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
167        libraries. This caused unwanted dependencies to be created. This problem
168        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
169        pcretest is linked with readline.
171    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
172        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
173        moved outside it again, because FALSE and TRUE are already defined in AIX,
174        but BOOL is not.
176    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
177        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
179    4.  The pcregrep documentation said spaces were inserted as well as colons (or
180        hyphens) following file names and line numbers when outputting matching
181        lines. This is not true; no spaces are inserted. I have also clarified the
182        wording for the --colour (or --color) option.
184    5.  In pcregrep, when --colour was used with -o, the list of matching strings
185        was not coloured; this is different to GNU grep, so I have changed it to be
186        the same.
188    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
189        each matching line was coloured. Now it goes on to look for further matches
190        of any of the test patterns, which is the same behaviour as GNU grep.
192    7.  A pattern that could match an empty string could cause pcregrep to loop; it
193        doesn't make sense to accept an empty string match in pcregrep, so I have
194        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
195        seems to be how GNU grep behaves.
197    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
198        start or after a newline", because the conditional assertion was not being
199        correctly handled. The rule now is that both the assertion and what follows
200        in the first alternative must satisfy the test.
202    9.  If auto-callout was enabled in a pattern with a conditional group whose
203        condition was an assertion, PCRE could crash during matching, both with
204        pcre_exec() and pcre_dfa_exec().
206    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
207        used for matching.
209    11. Unicode property support in character classes was not working for
210        characters (bytes) greater than 127 when not in UTF-8 mode.
212    12. Added the -M command line option to pcretest.
214    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
216    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
218    16. Added comments and documentation about mis-use of no_arg in the C++
219        wrapper.
221    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
222        from Martin Jerabek that uses macro names for all relevant character and
223        string constants.
225    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
226        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
227        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
228        these, but not everybody uses configure.
230    19. A conditional group that had only one branch was not being correctly
231        recognized as an item that could match an empty string. This meant that an
232        enclosing group might also not be so recognized, causing infinite looping
233        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
234        with the subject "ab", where knowledge that the repeated group can match
235        nothing is needed in order to break the loop.
237    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
238        exec(), but without supplying a callout function, matching went wrong.
240    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
241        leak if the size of the offset vector was greater than 30. When the vector
242        is smaller, the saved offsets during recursion go onto a local stack
243        vector, but for larger vectors malloc() is used. It was failing to free
244        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
245        error, in fact).
247    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
248        heapframe that is used only when UTF-8 support is enabled. This caused no
249        problem, but was untidy.
251    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
252        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
253        included within another project.
255    24. Steven Van Ingelgem's patches to add more options to the CMake support,
256        slightly modified by me:
258          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
259              not building pcregrep.
261          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
262              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
264    25. Forward references, both numeric and by name, in patterns that made use of
265        duplicate group numbers, could behave incorrectly or give incorrect errors,
266        because when scanning forward to find the reference group, PCRE was not
267        taking into account the duplicate group numbers. A pattern such as
268        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
270    26. Changed a few more instances of "const unsigned char *" to USPTR, making
271        the feature of a custom pointer more persuasive (as requested by a user).
273    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
274        pcretest.c, inside #ifndefs, because it seems they are sometimes already
275        pre-defined.
277    28. Added support for (*UTF8) at the start of a pattern.
279    29. Arrange for flags added by the "release type" setting in CMake to be shown
280        in the configuration summary.
283    Version 7.8 05-Sep-08
284    ---------------------
286    1.  Replaced UCP searching code with optimized version as implemented for Ad
287        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
288        stage table and inline lookup instead of a function, giving speed ups of 2
289        to 5 times on some simple patterns that I tested. Permission was given to
290        distribute the MultiStage2.py script that generates the tables (it's not in
291        the tarball, but is in the Subversion repository).
293    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
294        scripts.
296    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
297        a group with a zero qualifier. The result of the study could be incorrect,
298        or the function might crash, depending on the pattern.
300    4.  Caseless matching was not working for non-ASCII characters in back
301        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
302        It now works when Unicode Property Support is available.
304    5.  In pcretest, an escape such as \x{de} in the data was always generating
305        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
306        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
307        truncation.
309    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
311    7.  Added two (int) casts to pcregrep when printing the difference of two
312        pointers, in case they are 64-bit values.
314    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
315        test 2 if it fails.
317    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
318        and a #define of that name to empty if it is not externally set. This is to
319        allow users of MSVC to set it if necessary.
321    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
322        the convenience functions in the pcre_get.c source file.
324    11. An option change at the start of a pattern that had top-level alternatives
325        could cause overwriting and/or a crash. This command provoked a crash in
326        some environments:
328          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
330        This potential security problem was recorded as CVE-2008-2371.
332    12. For a pattern where the match had to start at the beginning or immediately
333        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
334        pcre_dfa_exec() could read past the end of the passed subject if there was
335        no match. To help with detecting such bugs (e.g. with valgrind), I modified
336        pcretest so that it places the subject at the end of its malloc-ed buffer.
338    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
339        exec() might read past the end of the data buffer in UTF-8 mode.
341    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
342        the data contained the byte 0x85 as part of a UTF-8 character within its
343        first line. This applied both to normal and DFA matching.
345    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
346        /^[^d]*?$/8 failed to match "abc".
348    16. Added a missing copyright notice to pcrecpp_internal.h.
350    17. Make it more clear in the documentation that values returned from
351        pcre_exec() in ovector are byte offsets, not character counts.
353    18. Tidied a few places to stop certain compilers from issuing warnings.
355    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
356        supplied by Stefan Weber. I made a further small update for 7.8 because
357        there is a change of source arrangements: the pcre_searchfuncs.c module is
358        replaced by pcre_ucd.c.
361    Version 7.7 07-May-08
362    ---------------------
364    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
365        a string to a long long, pretend we don't even have a long long." This is
366        done by checking for the strtoq, strtoll, and _strtoi64 functions.
368    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
369        pre-7.6 versions, which defined a global no_arg variable instead of putting
370        it in the RE class. (See also #8 below.)
372    3.  Remove a line of dead code, identified by coverity and reported by Nuno
373        Lopes.
375    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
377        (1) The include/exclude patterns were being applied to the whole pathnames
378            of files, instead of just to the final components.
380        (2) If there was more than one level of directory, the subdirectories were
381            skipped unless they satisfied the include/exclude conditions. This is
382            inconsistent with GNU grep (and could even be seen as contrary to the
383            pcregrep specification - which I improved to make it absolutely clear).
384            The action now is always to scan all levels of directory, and just
385            apply the include/exclude patterns to regular files.
387    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
388        --exclude_dir in the tests to avoid scanning .svn directories.
390    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
391        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
392        doesn't support NULs in patterns.
394    7.  Added some missing "const"s to declarations of static tables in
395        pcre_compile.c and pcre_dfa_exec.c.
397    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
398        caused by fix #2  above. (Subsequently also a second patch to fix the
399        first patch. And a third patch - this was a messy problem.)
401    9.  Applied Craig's patch to remove the use of push_back().
403    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
404        matching function regexec().
406    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
407        which, however, unlike Perl's \g{...}, are subroutine calls, not back
408        references. PCRE supports relative numbers with this syntax (I don't think
409        Oniguruma does).
411    12. Previously, a group with a zero repeat such as (...){0} was completely
412        omitted from the compiled regex. However, this means that if the group
413        was called as a subroutine from elsewhere in the pattern, things went wrong
414        (an internal error was given). Such groups are now left in the compiled
415        pattern, with a new opcode that causes them to be skipped at execution
416        time.
418    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
419        to the way PCRE behaves:
421        (a) A lone ] character is dis-allowed (Perl treats it as data).
423        (b) A back reference to an unmatched subpattern matches an empty string
424            (Perl fails the current match path).
426        (c) A data ] in a character class must be notated as \] because if the
427            first data character in a class is ], it defines an empty class. (In
428            Perl it is not possible to have an empty class.) The empty class []
429            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
430            The negative empty class [^] matches any one character, independently
431            of the DOTALL setting.
433    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
434        non-existent subpattern following a character class starting with ']' and
435        containing () gave an internal compiling error instead of "reference to
436        non-existent subpattern". Fortunately, when the pattern did exist, the
437        compiled code was correct. (When scanning forwards to check for the
438        existencd of the subpattern, it was treating the data ']' as terminating
439        the class, so got the count wrong. When actually compiling, the reference
440        was subsequently set up correctly.)
442    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
443        it was being rejected as not supported by pcre_dfa_exec(), even though
444        other assertions are supported. I have made pcre_dfa_exec() support
445        (*FAIL).
447    16. The implementation of 13c above involved the invention of a new opcode,
448        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
449        cannot be changed at match time, I realized I could make a small
450        improvement to matching performance by compiling OP_ALLANY instead of
451        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
452        on the OP_ANY path.
454    17. Compiling pcretest on Windows with readline support failed without the
455        following two fixes: (1) Make the unistd.h include conditional on
456        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
458    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
459        ncurses library to be included for pcretest when ReadLine support is
460        requested, but also to allow for it to be overridden. This patch came from
461        Daniel Bergström.
463    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
464        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
465        any errors with the current Unicode tables. Thanks to Peter Kankowski for
466        spotting this.
469    Version 7.6 28-Jan-08
470    ---------------------
472    1.  A character class containing a very large number of characters with
473        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
474        overflow.
476    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
477        HAVE_LONG_LONG is not defined.
479    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
480        bring them up to date and include new features. This patch includes:
482        - Fixed PH's badly added libz and libbz2 support.
483        - Fixed a problem with static linking.
484        - Added pcredemo. [But later removed - see 7 below.]
485        - Fixed dftables problem and added an option.
486        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
487            HAVE_LONG_LONG.
488        - Added readline support for pcretest.
489        - Added an listing of the option settings after cmake has run.
491    4.  A user submitted a patch to Makefile that makes it easy to create
492        "pcre.dll" under mingw when using Configure/Make. I added stuff to
493        Makefile.am that cause it to include this special target, without
494        affecting anything else. Note that the same mingw target plus all
495        the other distribution libraries and programs are now supported
496        when configuring with CMake (see 6 below) instead of with
497        Configure/Make.
499    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
500        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
501        exported in the Windows port". It has not yet been confirmed that the patch
502        solves the problem, but it does no harm.
504    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
505        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
506        with CMake, and also correct the comment about stack recursion.
508    7.  Remove the automatic building of pcredemo from the ./configure system and
509        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
510        of a program that users should build themselves after PCRE is installed, so
511        building it automatically is not really right. What is more, it gave
512        trouble in some build environments.
514    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
517    Version 7.5 10-Jan-08
518    ---------------------
520    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
521        values in parens when parsing an RE using the C++ wrapper."
523    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
524        Characters greater than 255 were excluded from the class instead of being
525        included.
527    3.  The same bug as (2) above applied to negated POSIX classes such as
528        [:^space:].
530    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
531        defined or documented. It seems to have been a typo for PCRE_STATIC, so
532        I have changed it.
534    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
535        first named subpattern) and a construct such as (?&a) would reference the
536        first named subpattern whose name started with "a" (in other words, the
537        length check was missing). Both these problems are fixed. "Subpattern name
538        expected" is now given for (?&) (a zero-length name), and this patch also
539        makes it give the same error for \k'' (previously it complained that that
540        was a reference to a non-existent subpattern).
542    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
543        this is right because (?- can be followed by option settings as well as by
544        digits. I have, however, made the messages clearer.
546    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
547        than the number used in the conditional) now cause a compile-time error.
548        This is actually not compatible with Perl, which accepts such patterns, but
549        treats the conditional as always being FALSE (as PCRE used to), but it
550        seems to me that giving a diagnostic is better.
552    8.  Change "alphameric" to the more common word "alphanumeric" in comments
553        and messages.
555    9.  Fix two occurrences of "backslash" in comments that should have been
556        "backspace".
558    10. Remove two redundant lines of code that can never be obeyed (their function
559        was moved elsewhere).
561    11. The program that makes PCRE's Unicode character property table had a bug
562        which caused it to generate incorrect table entries for sequences of
563        characters that have the same character type, but are in different scripts.
564        It amalgamated them into a single range, with the script of the first of
565        them. In other words, some characters were in the wrong script. There were
566        thirteen such cases, affecting characters in the following ranges:
568          U+002b0 - U+002c1
569          U+0060c - U+0060d
570          U+0061e - U+00612
571          U+0064b - U+0065e
572          U+0074d - U+0076d
573          U+01800 - U+01805
574          U+01d00 - U+01d77
575          U+01d9b - U+01dbf
576          U+0200b - U+0200f
577          U+030fc - U+030fe
578          U+03260 - U+0327f
579          U+0fb46 - U+0fbb1
580          U+10450 - U+1049d
582    12. The -o option (show only the matching part of a line) for pcregrep was not
583        compatible with GNU grep in that, if there was more than one match in a
584        line, it showed only the first of them. It now behaves in the same way as
585        GNU grep.
587    13. If the -o and -v options were combined for pcregrep, it printed a blank
588        line for every non-matching line. GNU grep prints nothing, and pcregrep now
589        does the same. The return code can be used to tell if there were any
590        non-matching lines.
592    14. Added --file-offsets and --line-offsets to pcregrep.
594    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
595        infinitely looping recursion. The bug was that positive lookaheads were not
596        being skipped when checking for a possible empty match (negative lookaheads
597        and both kinds of lookbehind were skipped).
599    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
600        inclusion of <windows.h> to before rather than after the definition of
601        INVALID_FILE_ATTRIBUTES (patch from David Byron).
603    17. Specifying a possessive quantifier with a specific limit for a Unicode
604        character property caused pcre_compile() to compile bad code, which led at
605        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
606        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
607        caused the error; without that there was no problem.
609    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
611    19. Added --enable-pcretest-libreadline.
613    20. In pcrecpp.cc, the variable 'count' was incremented twice in
614        RE::GlobalReplace(). As a result, the number of replacements returned was
615        double what it should be. I removed one of the increments, but Craig sent a
616        later patch that removed the other one (the right fix) and added unit tests
617        that check the return values (which was not done before).
619    21. Several CMake things:
621        (1) Arranged that, when cmake is used on Unix, the libraries end up with
622            the names libpcre and libpcreposix, not just pcre and pcreposix.
624        (2) The above change means that pcretest and pcregrep are now correctly
625            linked with the newly-built libraries, not previously installed ones.
629    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
630        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
631        UTF-8 newline character). The key issue is that the pattern starts .*;
632        this means that the match must be either at the beginning, or after a
633        newline. The bug was in the code for advancing after a failed match and
634        checking that the new position followed a newline. It was not taking
635        account of UTF-8 characters correctly.
637    23. PCRE was behaving differently from Perl in the way it recognized POSIX
638        character classes. PCRE was not treating the sequence [:...:] as a
639        character class unless the ... were all letters. Perl, however, seems to
640        allow any characters between [: and :], though of course it rejects as
641        unknown any "names" that contain non-letters, because all the known class
642        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
643        for example, whereas PCRE did not - it did not recognize a POSIX character
644        class. This seemed a bit dangerous, so the code has been changed to be
645        closer to Perl. The behaviour is not identical to Perl, because PCRE will
646        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
647        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
648        Perl does, and where it didn't before.
650    24. Rewrite so as to remove the single use of %n from pcregrep because in some
651        Windows environments %n is disabled by default.
654    Version 7.4 21-Sep-07
655    ---------------------
657    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
658        means that a class such as [\s] counted as "explicit reference to CR or
659        LF". That isn't really right - the whole point of the change was to try to
660        help when there was an actual mention of one of the two characters. So now
661        the change happens only if \r or \n (or a literal CR or LF) character is
662        encountered.
664    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
665        of both had grown to the point where there were only 3 bits left.
666        Fortunately, there was spare space in the data structure, and so I have
667        moved the internal flags into a new 16-bit field to free up more option
668        bits.
670    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
671        but did not set the internal JCHANGED flag - either of these is enough to
672        control the way the "get" function works - but the PCRE_INFO_JCHANGED
673        facility is supposed to tell if (?J) was ever used, so now (?J) at the
674        start sets both bits.
676    4.  Added options (at build time, compile time, exec time) to change \R from
677        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
679    5.  doc/pcresyntax.html was missing from the distribution.
681    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
682        compatibility, even though it is no longer used.
684    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
685        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
686        windows.h file is present (where different names are used). [This was
687        reversed later after testing - see 16 below.]
689    8.  Changed all #include <config.h> to #include "config.h". There were also
690        some further <pcre.h> cases that I changed to "pcre.h".
692    9.  When pcregrep was used with the --colour option, it missed the line ending
693        sequence off the lines that it output.
695    10. It was pointed out to me that arrays of string pointers cause lots of
696        relocations when a shared library is dynamically loaded. A technique of
697        using a single long string with a table of offsets can drastically reduce
698        these. I have refactored PCRE in four places to do this. The result is
699        dramatic:
701          Originally:                          290
702          After changing UCP table:            187
703          After changing error message table:   43
704          After changing table of "verbs"       36
705          After changing table of Posix names   22
707        Thanks to the folks working on Gregex for glib for this insight.
709    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
710        unicode-properties was also set.
712    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
714    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
715        checked only for CRLF.
717    14. Added casts to pcretest.c to avoid compiler warnings.
719    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
721    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
722        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
723        entirely. This removes changes made in 7 above.
725    17. The CMake files have been updated, and there is now more information about
726        building with CMake in the NON-UNIX-USE document.
729    Version 7.3 28-Aug-07
730    ---------------------
732     1. In the rejigging of the build system that eventually resulted in 7.1, the
733        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
734        brackets there is not right, since it causes compilers to look for an
735        installed pcre.h, not the version that is in the source that is being
736        compiled (which of course may be different). I have changed it back to:
738          #include "pcre.h"
740        I have a vague recollection that the change was concerned with compiling in
741        different directories, but in the new build system, that is taken care of
742        by the VPATH setting the Makefile.
744     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
745        when the subject happened to end in the byte 0x85 (e.g. if the last
746        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
747        characters but of course it shouldn't be taken as a newline when it is part
748        of another character. The bug was that, for an unlimited repeat of . in
749        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
750        characters when looking for a newline.
752     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
754     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
755        in debug output.
757     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
758        long printing in the pcrecpp unittest when running under MinGW.
760     6. ESC_K was left out of the EBCDIC table.
762     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
763        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
764        limit also applies to "virtual nesting" when a pattern is recursive, and in
765        this case 1000 isn't so big. I have been able to remove this limit at the
766        expense of backing off one optimization in certain circumstances. Normally,
767        when pcre_exec() would call its internal match() function recursively and
768        immediately return the result unconditionally, it uses a "tail recursion"
769        feature to save stack. However, when a subpattern that can match an empty
770        string has an unlimited repetition quantifier, it no longer makes this
771        optimization. That gives it a stack frame in which to save the data for
772        checking that an empty string has been matched. Previously this was taken
773        from the 1000-entry workspace that had been reserved. So now there is no
774        explicit limit, but more stack is used.
776     8. Applied Daniel's patches to solve problems with the import/export magic
777        syntax that is required for Windows, and which was going wrong for the
778        pcreposix and pcrecpp parts of the library. These were overlooked when this
779        problem was solved for the main library.
781     9. There were some crude static tests to avoid integer overflow when computing
782        the size of patterns that contain repeated groups with explicit upper
783        limits. As the maximum quantifier is 65535, the maximum group length was
784        set at 30,000 so that the product of these two numbers did not overflow a
785        32-bit integer. However, it turns out that people want to use groups that
786        are longer than 30,000 bytes (though not repeat them that many times).
787        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
788        made it possible to implement the integer overflow checks in a much more
789        dynamic way, which I have now done. The artificial limitation on group
790        length has been removed - we now have only the limit on the total length of
791        the compiled pattern, which depends on the LINK_SIZE setting.
793    10. Fixed a bug in the documentation for get/copy named substring when
794        duplicate names are permitted. If none of the named substrings are set, the
795        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
796        empty string.
798    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
799        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
800        because the ] is interpreted as the first data character and the
801        terminating ] is not found. PCRE has been made compatible with Perl in this
802        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
803        cause memory overwriting.
805    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
806        string has been matched (to stop an infinite loop). It was not recognizing
807        a conditional subpattern that could match an empty string if that
808        subpattern was within another subpattern. For example, it looped when
809        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
810        condition was not nested. This bug has been fixed.
812    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
813        past the start of the subject in the presence of bytes with the top bit
814        set, for example "\x8aBCD".
816    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
817        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
819    14. Optimized (?!) to (*FAIL).
821    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
822        This restricts code points to be within the range 0 to 0x10FFFF, excluding
823        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
824        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
825        does: it's just the validity check that is more restrictive.
827    16. Inserted checks for integer overflows during escape sequence (backslash)
828        processing, and also fixed erroneous offset values for syntax errors during
829        backslash processing.
831    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
832        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
834    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
835        caused an overrun.
837    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
838        something other than just ASCII characters) inside a group that had an
839        unlimited repeat caused a loop at compile time (while checking to see
840        whether the group could match an empty string).
842    20. Debugging a pattern containing \p or \P could cause a crash. For example,
843        [\P{Any}] did so. (Error in the code for printing property names.)
845    21. An orphan \E inside a character class could cause a crash.
847    22. A repeated capturing bracket such as (A)? could cause a wild memory
848        reference during compilation.
850    23. There are several functions in pcre_compile() that scan along a compiled
851        expression for various reasons (e.g. to see if it's fixed length for look
852        behind). There were bugs in these functions when a repeated \p or \P was
853        present in the pattern. These operators have additional parameters compared
854        with \d, etc, and these were not being taken into account when moving along
855        the compiled data. Specifically:
857        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
858            length.
860        (b) An item such as \pL+ within a repeated group could cause crashes or
861            loops.
863        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
864            "reference to non-existent subpattern" error.
866        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
868    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
869        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
871    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
873    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
874        character were causing crashes (broken optimization).
876    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
877        \p or \P) caused a compile-time loop.
879    28. More problems have arisen in unanchored patterns when CRLF is a valid line
880        break. For example, the unstudied pattern [\r\n]A does not match the string
881        "\r\nA" because change 7.0/46 below moves the current point on by two
882        characters after failing to match at the start. However, the pattern \nA
883        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
884        the same is true. There doesn't seem any very clean way out of this, but
885        what I have chosen to do makes the common cases work: PCRE now takes note
886        of whether there can be an explicit match for \r or \n anywhere in the
887        pattern, and if so, 7.0/46 no longer applies. As part of this change,
888        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
889        pattern has explicit CR or LF references.
891    29. Added (*CR) etc for changing newline setting at start of pattern.
894    Version 7.2 19-Jun-07
895    ---------------------
897     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
898        which is apparently normally available under Windows.
900     2. Re-jig the pcregrep tests with different newline settings in an attempt
901        to make them independent of the local environment's newline setting.
903     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
905     4. Some of the "internals" tests were previously cut out when the link size
906        was not 2, because the output contained actual offsets. The recent new
907        "Z" feature of pcretest means that these can be cut out, making the tests
908        usable with all link sizes.
910     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
911        stack recursion. This gives a massive performance boost under BSD, but just
912        a small improvement under Linux. However, it saves one field in the frame
913        in all cases.
915     6. Added more features from the forthcoming Perl 5.10:
917        (a) (?-n) (where n is a string of digits) is a relative subroutine or
918            recursion call. It refers to the nth most recently opened parentheses.
920        (b) (?+n) is also a relative subroutine call; it refers to the nth next
921            to be opened parentheses.
923        (c) Conditions that refer to capturing parentheses can be specified
924            relatively, for example, (?(-2)... or (?(+3)...
926        (d) \K resets the start of the current match so that everything before
927            is not part of it.
929        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
931        (f) \g{name} is another synonym - part of Perl 5.10's unification of
932            reference syntax.
934        (g) (?| introduces a group in which the numbering of parentheses in each
935            alternative starts with the same number.
937        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
939     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
942     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
943        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
944        for detecting groups that can match an empty string.
946     9. A pattern with a very large number of alternatives (more than several
947        hundred) was running out of internal workspace during the pre-compile
948        phase, where pcre_compile() figures out how much memory will be needed. A
949        bit of new cunning has reduced the workspace needed for groups with
950        alternatives. The 1000-alternative test pattern now uses 12 bytes of
951        workspace instead of running out of the 4096 that are available.
953    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
955    11. Applied patch from Google to remove an optimization that didn't quite work.
956        The report of the bug said:
958          pcrecpp::RE("a*").FullMatch("aaa") matches, while
959          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
960          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
962    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
963        it matched the wrong number of bytes.
966    Version 7.1 24-Apr-07
967    ---------------------
969     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
970        that is more "standard", making use of automake and other Autotools. There
971        is some re-arrangement of the files and adjustment of comments consequent
972        on this.
974     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
975        for recursive directory scanning broke on some systems because the files
976        are not scanned in any specific order and on different systems the order
977        was different. A call to "sort" has been inserted into RunGrepTest for the
978        approprate test as a short-term fix. In the longer term there may be an
979        alternative.
981     3. I had an email from Eric Raymond about problems translating some of PCRE's
982        man pages to HTML (despite the fact that I distribute HTML pages, some
983        people do their own conversions for various reasons). The problems
984        concerned the use of low-level troff macros .br and .in. I have therefore
985        removed all such uses from the man pages (some were redundant, some could
986        be replaced by .nf/.fi pairs). The 132html script that I use to generate
987        HTML has been updated to handle .nf/.fi and to complain if it encounters
988        .br or .in.
990     4. Updated comments in configure.ac that get placed in config.h.in and also
991        arranged for config.h to be included in the distribution, with the name
992        config.h.generic, for the benefit of those who have to compile without
993        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
995     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
996        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
997        makevp.bat for the current PCRE, using the additional files
998        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1000     6. A Windows user reported a minor discrepancy with test 2, which turned out
1001        to be caused by a trailing space on an input line that had got lost in his
1002        copy. The trailing space was an accident, so I've just removed it.
1004     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1005        that is needed.
1007     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1008        as "const" (a) because they are and (b) because it helps the PHP
1009        maintainers who have recently made a script to detect big data structures
1010        in the php code that should be moved to the .rodata section. I remembered
1011        to update Builducptable as well, so it won't revert if ucptable.h is ever
1012        re-created.
1014     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1015        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1016        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1017        support is not required. This saves 1.5-2K of code, which is important in
1018        some applications.
1020        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1021        so as not to refer to the tables, even though these functions will never be
1022        called when UTF-8 support is disabled. Otherwise there are problems with a
1023        shared library.
1025    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1027        (a) It was defining its arguments as char * instead of void *.
1029        (b) It was assuming that all moves were upwards in memory; this was true
1030            a long time ago when I wrote it, but is no longer the case.
1032        The emulated memove() is provided for those environments that have neither
1033        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1034        is clearly not the case, as these two bugs were recently reported.
1036    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1037        and Detrail to create the HTML documentation, the .txt form of the man
1038        pages, and it removes trailing spaces from listed files. It also creates
1039        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1040        case, it wraps all the #defines with #ifndefs. This script should be run
1041        before "make dist".
1043    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1044        with Unicode property support.
1046        (a) For a maximizing quantifier, if the two different cases of the
1047            character were of different lengths in their UTF-8 codings (there are
1048            some cases like this - I found 11), and the matching function had to
1049            back up over a mixture of the two cases, it incorrectly assumed they
1050            were both the same length.
1052        (b) When PCRE was configured to use the heap rather than the stack for
1053            recursion during matching, it was not correctly preserving the data for
1054            the other case of a UTF-8 character when checking ahead for a match
1055            while processing a minimizing repeat. If the check also involved
1056            matching a wide character, but failed, corruption could cause an
1057            erroneous result when trying to check for a repeat of the original
1058            character.
1060    13. Some tidying changes to the testing mechanism:
1062        (a) The RunTest script now detects the internal link size and whether there
1063            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1064            values substituted by "configure". (The RunGrepTest script already did
1065            this for UTF-8.) The configure.ac script no longer substitutes the
1066            relevant variables.
1068        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1069            with length and offset values. This means that the output is different
1070            for different internal link sizes. Test 2 is skipped for link sizes
1071            other than 2 because of this, bypassing the problem. Unfortunately,
1072            there was also a test in test 3 (the locale tests) that used /B and
1073            failed for link sizes other than 2. Rather than cut the whole test out,
1074            I have added a new /Z option to pcretest that replaces the length and
1075            offset values with spaces. This is now used to make test 3 independent
1076            of link size. (Test 2 will be tidied up later.)
1078    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1079        segmentation fault instead of returning the appropriate error message.
1081    15. In multiline mode when the newline sequence was set to "any", the pattern
1082        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1083        This doesn't seem right; it now treats the CRLF combination as the line
1084        ending, and so does not match in that case. It's only a pattern such as ^$
1085        that would hit this one: something like ^ABC$ would have failed after \r
1086        and then tried again after \r\n.
1088    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1089        in an attempt to make files that differ only in their line terminators
1090        compare equal. This works on Linux.
1092    17. Under certain error circumstances pcregrep might try to free random memory
1093        as it exited. This is now fixed, thanks to valgrind.
1095    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1096        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1097        was because its rules for how to advance for /g after matching an empty
1098        string at the end of a line did not allow for this case. They now check for
1099        it specially.
1101    20. pcretest is supposed to handle patterns and data of any length, by
1102        extending its buffers when necessary. It was getting this wrong when the
1103        buffer for a data line had to be extended.
1105    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1106        CRLF as a newline sequence.
1108    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1109        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1110        I have nevertheless tidied it up.
1112    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1114    24. Added a man page for pcre-config.
1117    Version 7.0 19-Dec-06
1118    ---------------------
1120     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1121        moving to gcc 4.1.1.
1123     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1124        sys/time.h, which is documented as needed for this function. It doesn't
1125        seem to matter on Linux, but it showed up on some releases of OS X.
1127     3. It seems that there are systems where bytes whose values are greater than
1128        127 match isprint() in the "C" locale. The "C" locale should be the
1129        default when a C program starts up. In most systems, only ASCII printing
1130        characters match isprint(). This difference caused the output from pcretest
1131        to vary, making some of the tests fail. I have changed pcretest so that:
1133        (a) When it is outputting text in the compiled version of a pattern, bytes
1134            other than 32-126 are always shown as hex escapes.
1136        (b) When it is outputting text that is a matched part of a subject string,
1137            it does the same, unless a different locale has been set for the match
1138            (using the /L modifier). In this case, it uses isprint() to decide.
1140     4. Fixed a major bug that caused incorrect computation of the amount of memory
1141        required for a compiled pattern when options that changed within the
1142        pattern affected the logic of the preliminary scan that determines the
1143        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1144        that the computed length was too small. The symptoms of this bug were
1145        either the PCRE error "internal error: code overflow" from pcre_compile(),
1146        or a glibc crash with a message such as "pcretest: free(): invalid next
1147        size (fast)". Examples of patterns that provoked this bug (shown in
1148        pcretest format) are:
1150          /(?-x: )/x
1151          /(?x)(?-x: \s*#\s*)/
1152          /((?i)[\x{c0}])/8
1153          /(?i:[\x{c0}])/8
1155        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1156        is now done differently.
1158     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1159        wrapper classes; (b) implement a new function in the C++ scanner that is
1160        more efficient than the old way of doing things because it avoids levels of
1161        recursion in the regex matching; (c) add a paragraph to the documentation
1162        for the FullMatch() function.
1164     6. The escape sequence \n was being treated as whatever was defined as
1165        "newline". Not only was this contrary to the documentation, which states
1166        that \n is character 10 (hex 0A), but it also went horribly wrong when
1167        "newline" was defined as CRLF. This has been fixed.
1169     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1170        was being set to -1 for the "end of line" case (supposedly a value that no
1171        character can have). Though this value is never used (the check for end of
1172        line is "zero bytes in current character"), it caused compiler complaints.
1173        I've changed it to 0xffffffff.
1175     8. In pcre_version.c, the version string was being built by a sequence of
1176        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1177        string (as it is for production releases) called a macro with an empty
1178        argument. The C standard says the result of this is undefined. The gcc
1179        compiler treats it as an empty string (which was what was wanted) but it is
1180        reported that Visual C gives an error. The source has been hacked around to
1181        avoid this problem.
1183     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1184        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1185        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1186        of them did).
1188    10. Originally, pcretest opened its input and output without "b"; then I was
1189        told that "b" was needed in some environments, so it was added for release
1190        5.0 to both the input and output. (It makes no difference on Unix-like
1191        systems.) Later I was told that it is wrong for the input on Windows. I've
1192        now abstracted the modes into two macros, to make it easier to fiddle with
1193        them, and removed "b" from the input mode under Windows.
1195    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1197    12. Added -help and --help to pcretest as an official way of being reminded
1198        of the options.
1200    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1201        and pcrecpp.cc because they annoy compilers at high warning levels.
1203    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1205    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1206        scripts are not C programs :-) and which was not noticed because it works
1207        on Linux.
1209    16. pcretest is supposed to handle any length of pattern and data line (as one
1210        line or as a continued sequence of lines) by extending its input buffer if
1211        necessary. This feature was broken for very long pattern lines, leading to
1212        a string of junk being passed to pcre_compile() if the pattern was longer
1213        than about 50K.
1215    17. I have done a major re-factoring of the way pcre_compile() computes the
1216        amount of memory needed for a compiled pattern. Previously, there was code
1217        that made a preliminary scan of the pattern in order to do this. That was
1218        OK when PCRE was new, but as the facilities have expanded, it has become
1219        harder and harder to keep it in step with the real compile phase, and there
1220        have been a number of bugs (see for example, 4 above). I have now found a
1221        cunning way of running the real compile function in a "fake" mode that
1222        enables it to compute how much memory it would need, while actually only
1223        ever using a few hundred bytes of working memory and without too many
1224        tests of the mode. This should make future maintenance and development
1225        easier. A side effect of this work is that the limit of 200 on the nesting
1226        depth of parentheses has been removed (though this was never a serious
1227        limitation, I suspect). However, there is a downside: pcre_compile() now
1228        runs more slowly than before (30% or more, depending on the pattern). I
1229        hope this isn't a big issue. There is no effect on runtime performance.
1231    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1232        newline (only possible for the last line of a file) and it was a
1233        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1235    19. Added additional timing features to pcretest. (1) The -tm option now times
1236        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1237        separate command line item, by a number that specifies the number of
1238        repeats to use when timing. The default is 50000; this gives better
1239        precision, but takes uncomfortably long for very large patterns.
1241    20. Extended pcre_study() to be more clever in cases where a branch of a
1242        subpattern has no definite first character. For example, (a*|b*)[cd] would
1243        previously give no result from pcre_study(). Now it recognizes that the
1244        first character must be a, b, c, or d.
1246    21. There was an incorrect error "recursive call could loop indefinitely" if
1247        a subpattern (or the entire pattern) that was being tested for matching an
1248        empty string contained only one non-empty item after a nested subpattern.
1249        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1250        incorrectly, because the \d was being skipped in the check.
1252    22. The pcretest program now has a new pattern option /B and a command line
1253        option -b, which is equivalent to adding /B to every pattern. This causes
1254        it to show the compiled bytecode, without the additional information that
1255        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1256        is the same as /B/I).
1258    23. A new optimization is now able automatically to treat some sequences such
1259        as a*b as a*+b. More specifically, if something simple (such as a character
1260        or a simple class like \d) has an unlimited quantifier, and is followed by
1261        something that cannot possibly match the quantified thing, the quantifier
1262        is automatically "possessified".
1264    24. A recursive reference to a subpattern whose number was greater than 39
1265        went wrong under certain circumstances in UTF-8 mode. This bug could also
1266        have affected the operation of pcre_study().
1268    25. Realized that a little bit of performance could be had by replacing
1269        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1271    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1273    27. Possessive quantifiers such as a++ were previously implemented by turning
1274        them into atomic groups such as ($>a+). Now they have their own opcodes,
1275        which improves performance. This includes the automatically created ones
1276        from 23 above.
1278    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1279        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1280        the first matched character to be a colon. This applied both to named and
1281        numbered groups.
1283    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1285    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1286        building PCRE on Windows easier, so I have included it in the distribution.
1288    31. There is now a check in pcretest against a ridiculously large number being
1289        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1290        loop, the loop is abandoned.
1292    32. Forward references to subpatterns in conditions such as (?(2)...) where
1293        subpattern 2 is defined later cause pcre_compile() to search forwards in
1294        the pattern for the relevant set of parentheses. This search went wrong
1295        when there were unescaped parentheses in a character class, parentheses
1296        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1298    33. "Subroutine" calls and backreferences were previously restricted to
1299        referencing subpatterns earlier in the regex. This restriction has now
1300        been removed.
1302    34. Added a number of extra features that are going to be in Perl 5.10. On the
1303        whole, these are just syntactic alternatives for features that PCRE had
1304        previously implemented using the Python syntax or my own invention. The
1305        other formats are all retained for compatibility.
1307        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1308            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1309            also .NET compatible.
1311        (b) A recursion or subroutine call to a named group can now be defined as
1312            (?&name) as well as (?P>name).
1314        (c) A backreference to a named group can now be defined as \k<name> or
1315            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1316            5.10, are also .NET compatible.
1318        (d) A conditional reference to a named group can now use the syntax
1319            (?(<name>) or (?('name') as well as (?(name).
1321        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1322            groups (named and numbered) that are never evaluated inline, but can be
1323            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1324            is always false. There may be only one alternative in such a group.
1326        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1327            as the simple (?(R). The condition is true only if the most recent
1328            recursion is that of the given number or name. It does not search out
1329            through the entire recursion stack.
1331        (g) The escape \gN or \g{N} has been added, where N is a positive or
1332            negative number, specifying an absolute or relative reference.
1334    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1335        some "unreachable code" warnings.
1337    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1338        things, this adds five new scripts.
1340    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1341        There were also incompatibilities regarding the handling of \Q..\E inside
1342        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1343        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1345    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1346        matches an empty string, and forcibly breaks the loop. There were bugs in
1347        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1348        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1349        separate and independent bugs (that affected different cases) have been
1350        fixed.
1352    39. Refactored the code to abolish the use of different opcodes for small
1353        capturing bracket numbers. This is a tidy that I avoided doing when I
1354        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1355        The new approach is not only tidier, it makes it possible to reduce the
1356        memory needed to fix the previous bug (38).
1358    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1359        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1360        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1361        mode.
1363    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1364        report.
1366    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1367        copy construction and assignment in the C++ wrapper.
1369    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1370        couple of bugs that could have given wrong results in the "--newline=crlf"
1371        case.
1373    44. Added a number of casts and did some reorganization of signed/unsigned int
1374        variables following suggestions from Dair Grant. Also renamed the variable
1375        "this" as "item" because it is a C++ keyword.
1377    45. Arranged for dftables to add
1379          #include "pcre_internal.h"
1381        to pcre_chartables.c because without it, gcc 4.x may remove the array
1382        definition from the final binary if PCRE is built into a static library and
1383        dead code stripping is activated.
1385    46. For an unanchored pattern, if a match attempt fails at the start of a
1386        newline sequence, and the newline setting is CRLF or ANY, and the next two
1387        characters are CRLF, advance by two characters instead of one.
1390    Version 6.7 04-Jul-06
1391    ---------------------
1393     1. In order to handle tests when input lines are enormously long, pcretest has
1394        been re-factored so that it automatically extends its buffers when
1395        necessary. The code is crude, but this _is_ just a test program. The
1396        default size has been increased from 32K to 50K.
1398     2. The code in pcre_study() was using the value of the re argument before
1399        testing it for NULL. (Of course, in any sensible call of the function, it
1400        won't be NULL.)
1402     3. The memmove() emulation function in pcre_internal.h, which is used on
1403        systems that lack both memmove() and bcopy() - that is, hardly ever -
1404        was missing a "static" storage class specifier.
1406     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1407        containing an extended class (one that cannot be represented by a bitmap
1408        because it contains high-valued characters or Unicode property items, e.g.
1409        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1410        pattern, but PCRE should not loop if you do not (it no longer does).
1411        [Detail: two cases were found: (a) a repeated subpattern containing an
1412        extended class; (b) a recursive reference to a subpattern that followed a
1413        previous extended class. It wasn't skipping over the extended class
1414        correctly when UTF-8 mode was not set.]
1416     5. A negated single-character class was not being recognized as fixed-length
1417        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1418        compile error "lookbehind assertion is not fixed length".
1420     6. The RunPerlTest auxiliary script was showing an unexpected difference
1421        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1422        write a Perl script that can interpret lines of an input file either as
1423        byte characters or as UTF-8, which is what "perltest" was being required to
1424        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1425        can't do is switch easily at run time between having the "use utf8;" pragma
1426        or not. In the end, I fudged it by using the RunPerlTest script to insert
1427        "use utf8;" explicitly for the UTF-8 tests.
1429     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1430        the end of the subject string, contrary to the documentation and to what
1431        Perl does. This was true of both matching functions. Now it matches only at
1432        the start of the subject and immediately after *internal* newlines.
1434     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1435        a pointer to an int instead of a pointer to an unsigned long int. This
1436        caused problems on 64-bit systems.
1438     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1439        instance of the 'standard' template library not being so standard".
1441    10. There was no check on the number of named subpatterns nor the maximum
1442        length of a subpattern name. The product of these values is used to compute
1443        the size of the memory block for a compiled pattern. By supplying a very
1444        long subpattern name and a large number of named subpatterns, the size
1445        computation could be caused to overflow. This is now prevented by limiting
1446        the length of names to 32 characters, and the number of named subpatterns
1447        to 10,000.
1449    11. Subpatterns that are repeated with specific counts have to be replicated in
1450        the compiled pattern. The size of memory for this was computed from the
1451        length of the subpattern and the repeat count. The latter is limited to
1452        65535, but there was no limit on the former, meaning that integer overflow
1453        could in principle occur. The compiled length of a repeated subpattern is
1454        now limited to 30,000 bytes in order to prevent this.
1456    12. Added the optional facility to have named substrings with the same name.
1458    13. Added the ability to use a named substring as a condition, using the
1459        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1460        are numbers (not recommended). Forward references are permitted.
1462    14. Added forward references in named backreferences (if you see what I mean).
1464    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1465        pattern could run off the end of the subject. For example, the pattern
1466        "(?s)(.{1,5})"8 did this with the subject "ab".
1468    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1469        PCRE_CASELESS was set when matching characters that were quantified with ?
1470        or *.
1472    17. A character class other than a single negated character that had a minimum
1473        but no maximum quantifier - for example [ab]{6,} - was not handled
1474        correctly by pce_dfa_exec(). It would match only one character.
1476    18. A valid (though odd) pattern that looked like a POSIX character
1477        class but used an invalid character after [ (for example [[,abc,]]) caused
1478        pcre_compile() to give the error "Failed: internal error: code overflow" or
1479        in some cases to crash with a glibc free() error. This could even happen if
1480        the pattern terminated after [[ but there just happened to be a sequence of
1481        letters, a binary zero, and a closing ] in the memory that followed.
1483    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1484        over the years. Originally (before any Unicode support), just the bottom 8
1485        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1486        output from "man perlunicode" includes this:
1488          The regular expression compiler produces polymorphic opcodes.  That
1489          is, the pattern adapts to the data and automatically switches to
1490          the Unicode character scheme when presented with Unicode data--or
1491          instead uses a traditional byte scheme when presented with byte
1492          data.
1494        Sadly, a wide octal escape does not cause a switch, and in a string with
1495        no other multibyte characters, these octal escapes are treated as before.
1496        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1497        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1498        Unicode string.
1500        I have not perpetrated such confusion in PCRE. Up till now, it took just
1501        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1502        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1503        translate to the appropriate multibyte character.
1505    29. Applied some refactoring to reduce the number of warnings from Microsoft
1506        and Borland compilers. This has included removing the fudge introduced
1507        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1508        a warning about an unused variable.
1510    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1511        characters since release 4.0, because Perl (from release 5.004) does not.
1512        [Or at least, is documented not to: some releases seem to be in conflict
1513        with the documentation.] However, when a pattern was studied with
1514        pcre_study() and all its branches started with \s, PCRE still included VT
1515        as a possible starting character. Of course, this did no harm; it just
1516        caused an unnecessary match attempt.
1518    22. Removed a now-redundant internal flag bit that recorded the fact that case
1519        dependency changed within the pattern. This was once needed for "required
1520        byte" processing, but is no longer used. This recovers a now-scarce options
1521        bit. Also moved the least significant internal flag bit to the most-
1522        significant bit of the word, which was not previously used (hangover from
1523        the days when it was an int rather than a uint) to free up another bit for
1524        the future.
1526    23. Added support for CRLF line endings as well as CR and LF. As well as the
1527        default being selectable at build time, it can now be changed at runtime
1528        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1529        specify that it is scanning data with non-default line endings.
1531    24. Changed the definition of CXXLINK to make it agree with the definition of
1532        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1534    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1535        recursions. This makes a big different to stack usage for some patterns.
1537    26. If a subpattern containing a named recursion or subroutine reference such
1538        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1539        the space required for the compiled pattern went wrong and gave too small a
1540        value. Depending on the environment, this could lead to "Failed: internal
1541        error: code overflow at offset 49" or "glibc detected double free or
1542        corruption" errors.
1544    27. Applied patches from Google (a) to support the new newline modes and (b) to
1545        advance over multibyte UTF-8 characters in GlobalReplace.
1547    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1548        difference for some implementation of PCRE in some Windows version.
1550    29. Added some extra testing facilities to pcretest:
1552        \q<number>   in a data line sets the "match limit" value
1553        \Q<number>   in a data line sets the "match recursion limt" value
1554        -S <number>  sets the stack size, where <number> is in megabytes
1556        The -S option isn't available for Windows.
1559    Version 6.6 06-Feb-06
1560    ---------------------
1562     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1563        in pcreposix.h. I have copied the definition from pcre.h.
1565     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1566        because pcre.h is no longer a built file.
1568     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1569        not normally included in the compiled code.
1572  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1573  ---------------------  ---------------------

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