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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.00 05-Oct-09
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8        was out-of-date, and there was no check on the pcre_compile() error code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.
63    11. Partial matching with pcre_exec() is now more intuitive. A partial match
64        used to be given if ever the end of the subject was reached; now it is
65        given only if matching could not proceed because another character was
66        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
67        string "Z", which now yields "no match" instead of "partial match". In the
68        case of pcre_dfa_exec(), "no match" is given if every matching path for the
69        final character ended with (*FAIL).
71    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
72        if the pattern had a "must contain" character that was already found in the
73        earlier partial match, unless partial matching was again requested. For
74        example, with the pattern /dog.(body)?/, the "must contain" character is
75        "g". If the first part-match was for the string "dog", restarting with
76        "sbody" failed. This bug has been fixed.
78    13. The string returned by pcre_dfa_exec() after a partial match has been
79        changed so that it starts at the first inspected character rather than the
80        first character of the match. This makes a difference only if the pattern
81        starts with a lookbehind assertion or \b or \B (\K is not supported by
82        pcre_dfa_exec()). It's an incompatible change, but it makes the two
83        matching functions compatible, and I think it's the right thing to do.
85    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
86        so that the demonstration program is easily available in environments where
87        PCRE has not been installed from source.
89    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
90        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
91        library.
93    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
94        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
95        is not the first non-POSIX option to be added. Clearly some people find
96        these options useful.
98    17. If a caller to the POSIX matching function regexec() passes a non-zero
99        value for nmatch with a NULL value for pmatch, the value of
100        nmatch is forced to zero.
102    18. RunGrepTest did not have a test for the availability of the -u option of
103        the diff command, as RunTest does. It now checks in the same way as
104        RunTest, and also checks for the -b option.
106    19. If an odd number of negated classes containing just a single character
107        interposed, within parentheses, between a forward reference to a named
108        subpattern and the definition of the subpattern, compilation crashed with
109        an internal error, complaining that it could not find the referenced
110        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
111        [The bug was that it was starting one character too far in when skipping
112        over the character class, thus treating the ] as data rather than
113        terminating the class. This meant it could skip too much.]
115    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
116        /g option in pcretest when the pattern contains \K, which makes it possible
117        to have an empty string match not at the start, even when the pattern is
118        anchored. Updated pcretest and pcredemo to use this option.
120    21. If the maximum number of capturing subpatterns in a recursion was greater
121        than the maximum at the outer level, the higher number was returned, but
122        with unset values at the outer level. The correct (outer level) value is
123        now given.
125    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
126        PCRE did not set those parentheses (unlike Perl). I have now found a way to
127        make it do so. The string so far is captured, making this feature
128        compatible with Perl.
130    23. The tests have been re-organized, adding tests 11 and 12, to make it
131        possible to check the Perl 5.10 features against Perl 5.10.
133    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
134        pattern matches a fixed length string. PCRE did not allow this; now it
135        does. Neither allows recursion.
137    25. I finally figured out how to implement a request to provide the minimum
138        length of subject string that was needed in order to match a given pattern.
139        (It was back references and recursion that I had previously got hung up
140        on.) This code has now been added to pcre_study(); it finds a lower bound
141        to the length of subject needed. It is not necessarily the greatest lower
142        bound, but using it to avoid searching strings that are too short does give
143        some useful speed-ups. The value is available to calling programs via
144        pcre_fullinfo().
146    26. While implementing 25, I discovered to my embarrassment that pcretest had
147        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
148        study optimizations had never been tested with that matching function.
149        Oops. What is worse, even when it was passed study data, there was a bug in
150        pcre_dfa_exec() that meant it never actually used it. Double oops. There
151        were also very few tests of studied patterns with pcre_dfa_exec().
153    27. If (?| is used to create subpatterns with duplicate numbers, they are now
154        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
155        on the other side of the coin, they are no longer allowed to have different
156        names, because these cannot be distinguished in PCRE, and this has caused
157        confusion. (This is a difference from Perl.)
159    28. When duplicate subpattern names are present (necessarily with different
160        numbers, as required by 27 above), and a test is made by name in a
161        conditional pattern, either for a subpattern having been matched, or for
162        recursion in such a pattern, all the associated numbered subpatterns are
163        tested, and the overall condition is true if the condition is true for any
164        one of them. This is the way Perl works, and is also more like the way
165        testing by number works.
168    Version 7.9 11-Apr-09
169    ---------------------
171    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
172        (pcretest), all targets were linked against these libraries. This included
173        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
174        libraries. This caused unwanted dependencies to be created. This problem
175        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
176        pcretest is linked with readline.
178    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
179        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
180        moved outside it again, because FALSE and TRUE are already defined in AIX,
181        but BOOL is not.
183    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
184        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
186    4.  The pcregrep documentation said spaces were inserted as well as colons (or
187        hyphens) following file names and line numbers when outputting matching
188        lines. This is not true; no spaces are inserted. I have also clarified the
189        wording for the --colour (or --color) option.
191    5.  In pcregrep, when --colour was used with -o, the list of matching strings
192        was not coloured; this is different to GNU grep, so I have changed it to be
193        the same.
195    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
196        each matching line was coloured. Now it goes on to look for further matches
197        of any of the test patterns, which is the same behaviour as GNU grep.
199    7.  A pattern that could match an empty string could cause pcregrep to loop; it
200        doesn't make sense to accept an empty string match in pcregrep, so I have
201        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
202        seems to be how GNU grep behaves.
204    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
205        start or after a newline", because the conditional assertion was not being
206        correctly handled. The rule now is that both the assertion and what follows
207        in the first alternative must satisfy the test.
209    9.  If auto-callout was enabled in a pattern with a conditional group whose
210        condition was an assertion, PCRE could crash during matching, both with
211        pcre_exec() and pcre_dfa_exec().
213    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
214        used for matching.
216    11. Unicode property support in character classes was not working for
217        characters (bytes) greater than 127 when not in UTF-8 mode.
219    12. Added the -M command line option to pcretest.
221    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
223    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
225    16. Added comments and documentation about mis-use of no_arg in the C++
226        wrapper.
228    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
229        from Martin Jerabek that uses macro names for all relevant character and
230        string constants.
232    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
233        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
234        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
235        these, but not everybody uses configure.
237    19. A conditional group that had only one branch was not being correctly
238        recognized as an item that could match an empty string. This meant that an
239        enclosing group might also not be so recognized, causing infinite looping
240        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
241        with the subject "ab", where knowledge that the repeated group can match
242        nothing is needed in order to break the loop.
244    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
245        exec(), but without supplying a callout function, matching went wrong.
247    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
248        leak if the size of the offset vector was greater than 30. When the vector
249        is smaller, the saved offsets during recursion go onto a local stack
250        vector, but for larger vectors malloc() is used. It was failing to free
251        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
252        error, in fact).
254    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
255        heapframe that is used only when UTF-8 support is enabled. This caused no
256        problem, but was untidy.
258    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
259        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
260        included within another project.
262    24. Steven Van Ingelgem's patches to add more options to the CMake support,
263        slightly modified by me:
265          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
266              not building pcregrep.
268          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
269              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
271    25. Forward references, both numeric and by name, in patterns that made use of
272        duplicate group numbers, could behave incorrectly or give incorrect errors,
273        because when scanning forward to find the reference group, PCRE was not
274        taking into account the duplicate group numbers. A pattern such as
275        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
277    26. Changed a few more instances of "const unsigned char *" to USPTR, making
278        the feature of a custom pointer more persuasive (as requested by a user).
280    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
281        pcretest.c, inside #ifndefs, because it seems they are sometimes already
282        pre-defined.
284    28. Added support for (*UTF8) at the start of a pattern.
286    29. Arrange for flags added by the "release type" setting in CMake to be shown
287        in the configuration summary.
290    Version 7.8 05-Sep-08
291    ---------------------
293    1.  Replaced UCP searching code with optimized version as implemented for Ad
294        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
295        stage table and inline lookup instead of a function, giving speed ups of 2
296        to 5 times on some simple patterns that I tested. Permission was given to
297        distribute the MultiStage2.py script that generates the tables (it's not in
298        the tarball, but is in the Subversion repository).
300    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
301        scripts.
303    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
304        a group with a zero qualifier. The result of the study could be incorrect,
305        or the function might crash, depending on the pattern.
307    4.  Caseless matching was not working for non-ASCII characters in back
308        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
309        It now works when Unicode Property Support is available.
311    5.  In pcretest, an escape such as \x{de} in the data was always generating
312        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
313        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
314        truncation.
316    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
318    7.  Added two (int) casts to pcregrep when printing the difference of two
319        pointers, in case they are 64-bit values.
321    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
322        test 2 if it fails.
324    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
325        and a #define of that name to empty if it is not externally set. This is to
326        allow users of MSVC to set it if necessary.
328    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
329        the convenience functions in the pcre_get.c source file.
331    11. An option change at the start of a pattern that had top-level alternatives
332        could cause overwriting and/or a crash. This command provoked a crash in
333        some environments:
335          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
337        This potential security problem was recorded as CVE-2008-2371.
339    12. For a pattern where the match had to start at the beginning or immediately
340        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
341        pcre_dfa_exec() could read past the end of the passed subject if there was
342        no match. To help with detecting such bugs (e.g. with valgrind), I modified
343        pcretest so that it places the subject at the end of its malloc-ed buffer.
345    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
346        exec() might read past the end of the data buffer in UTF-8 mode.
348    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
349        the data contained the byte 0x85 as part of a UTF-8 character within its
350        first line. This applied both to normal and DFA matching.
352    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
353        /^[^d]*?$/8 failed to match "abc".
355    16. Added a missing copyright notice to pcrecpp_internal.h.
357    17. Make it more clear in the documentation that values returned from
358        pcre_exec() in ovector are byte offsets, not character counts.
360    18. Tidied a few places to stop certain compilers from issuing warnings.
362    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
363        supplied by Stefan Weber. I made a further small update for 7.8 because
364        there is a change of source arrangements: the pcre_searchfuncs.c module is
365        replaced by pcre_ucd.c.
368    Version 7.7 07-May-08
369    ---------------------
371    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
372        a string to a long long, pretend we don't even have a long long." This is
373        done by checking for the strtoq, strtoll, and _strtoi64 functions.
375    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
376        pre-7.6 versions, which defined a global no_arg variable instead of putting
377        it in the RE class. (See also #8 below.)
379    3.  Remove a line of dead code, identified by coverity and reported by Nuno
380        Lopes.
382    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
384        (1) The include/exclude patterns were being applied to the whole pathnames
385            of files, instead of just to the final components.
387        (2) If there was more than one level of directory, the subdirectories were
388            skipped unless they satisfied the include/exclude conditions. This is
389            inconsistent with GNU grep (and could even be seen as contrary to the
390            pcregrep specification - which I improved to make it absolutely clear).
391            The action now is always to scan all levels of directory, and just
392            apply the include/exclude patterns to regular files.
394    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
395        --exclude_dir in the tests to avoid scanning .svn directories.
397    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
398        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
399        doesn't support NULs in patterns.
401    7.  Added some missing "const"s to declarations of static tables in
402        pcre_compile.c and pcre_dfa_exec.c.
404    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
405        caused by fix #2  above. (Subsequently also a second patch to fix the
406        first patch. And a third patch - this was a messy problem.)
408    9.  Applied Craig's patch to remove the use of push_back().
410    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
411        matching function regexec().
413    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
414        which, however, unlike Perl's \g{...}, are subroutine calls, not back
415        references. PCRE supports relative numbers with this syntax (I don't think
416        Oniguruma does).
418    12. Previously, a group with a zero repeat such as (...){0} was completely
419        omitted from the compiled regex. However, this means that if the group
420        was called as a subroutine from elsewhere in the pattern, things went wrong
421        (an internal error was given). Such groups are now left in the compiled
422        pattern, with a new opcode that causes them to be skipped at execution
423        time.
425    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
426        to the way PCRE behaves:
428        (a) A lone ] character is dis-allowed (Perl treats it as data).
430        (b) A back reference to an unmatched subpattern matches an empty string
431            (Perl fails the current match path).
433        (c) A data ] in a character class must be notated as \] because if the
434            first data character in a class is ], it defines an empty class. (In
435            Perl it is not possible to have an empty class.) The empty class []
436            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
437            The negative empty class [^] matches any one character, independently
438            of the DOTALL setting.
440    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
441        non-existent subpattern following a character class starting with ']' and
442        containing () gave an internal compiling error instead of "reference to
443        non-existent subpattern". Fortunately, when the pattern did exist, the
444        compiled code was correct. (When scanning forwards to check for the
445        existencd of the subpattern, it was treating the data ']' as terminating
446        the class, so got the count wrong. When actually compiling, the reference
447        was subsequently set up correctly.)
449    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
450        it was being rejected as not supported by pcre_dfa_exec(), even though
451        other assertions are supported. I have made pcre_dfa_exec() support
452        (*FAIL).
454    16. The implementation of 13c above involved the invention of a new opcode,
455        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
456        cannot be changed at match time, I realized I could make a small
457        improvement to matching performance by compiling OP_ALLANY instead of
458        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
459        on the OP_ANY path.
461    17. Compiling pcretest on Windows with readline support failed without the
462        following two fixes: (1) Make the unistd.h include conditional on
463        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
465    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
466        ncurses library to be included for pcretest when ReadLine support is
467        requested, but also to allow for it to be overridden. This patch came from
468        Daniel Bergström.
470    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
471        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
472        any errors with the current Unicode tables. Thanks to Peter Kankowski for
473        spotting this.
476    Version 7.6 28-Jan-08
477    ---------------------
479    1.  A character class containing a very large number of characters with
480        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
481        overflow.
483    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
484        HAVE_LONG_LONG is not defined.
486    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
487        bring them up to date and include new features. This patch includes:
489        - Fixed PH's badly added libz and libbz2 support.
490        - Fixed a problem with static linking.
491        - Added pcredemo. [But later removed - see 7 below.]
492        - Fixed dftables problem and added an option.
493        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
494            HAVE_LONG_LONG.
495        - Added readline support for pcretest.
496        - Added an listing of the option settings after cmake has run.
498    4.  A user submitted a patch to Makefile that makes it easy to create
499        "pcre.dll" under mingw when using Configure/Make. I added stuff to
500        Makefile.am that cause it to include this special target, without
501        affecting anything else. Note that the same mingw target plus all
502        the other distribution libraries and programs are now supported
503        when configuring with CMake (see 6 below) instead of with
504        Configure/Make.
506    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
507        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
508        exported in the Windows port". It has not yet been confirmed that the patch
509        solves the problem, but it does no harm.
511    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
512        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
513        with CMake, and also correct the comment about stack recursion.
515    7.  Remove the automatic building of pcredemo from the ./configure system and
516        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
517        of a program that users should build themselves after PCRE is installed, so
518        building it automatically is not really right. What is more, it gave
519        trouble in some build environments.
521    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
524    Version 7.5 10-Jan-08
525    ---------------------
527    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
528        values in parens when parsing an RE using the C++ wrapper."
530    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
531        Characters greater than 255 were excluded from the class instead of being
532        included.
534    3.  The same bug as (2) above applied to negated POSIX classes such as
535        [:^space:].
537    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
538        defined or documented. It seems to have been a typo for PCRE_STATIC, so
539        I have changed it.
541    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
542        first named subpattern) and a construct such as (?&a) would reference the
543        first named subpattern whose name started with "a" (in other words, the
544        length check was missing). Both these problems are fixed. "Subpattern name
545        expected" is now given for (?&) (a zero-length name), and this patch also
546        makes it give the same error for \k'' (previously it complained that that
547        was a reference to a non-existent subpattern).
549    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
550        this is right because (?- can be followed by option settings as well as by
551        digits. I have, however, made the messages clearer.
553    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
554        than the number used in the conditional) now cause a compile-time error.
555        This is actually not compatible with Perl, which accepts such patterns, but
556        treats the conditional as always being FALSE (as PCRE used to), but it
557        seems to me that giving a diagnostic is better.
559    8.  Change "alphameric" to the more common word "alphanumeric" in comments
560        and messages.
562    9.  Fix two occurrences of "backslash" in comments that should have been
563        "backspace".
565    10. Remove two redundant lines of code that can never be obeyed (their function
566        was moved elsewhere).
568    11. The program that makes PCRE's Unicode character property table had a bug
569        which caused it to generate incorrect table entries for sequences of
570        characters that have the same character type, but are in different scripts.
571        It amalgamated them into a single range, with the script of the first of
572        them. In other words, some characters were in the wrong script. There were
573        thirteen such cases, affecting characters in the following ranges:
575          U+002b0 - U+002c1
576          U+0060c - U+0060d
577          U+0061e - U+00612
578          U+0064b - U+0065e
579          U+0074d - U+0076d
580          U+01800 - U+01805
581          U+01d00 - U+01d77
582          U+01d9b - U+01dbf
583          U+0200b - U+0200f
584          U+030fc - U+030fe
585          U+03260 - U+0327f
586          U+0fb46 - U+0fbb1
587          U+10450 - U+1049d
589    12. The -o option (show only the matching part of a line) for pcregrep was not
590        compatible with GNU grep in that, if there was more than one match in a
591        line, it showed only the first of them. It now behaves in the same way as
592        GNU grep.
594    13. If the -o and -v options were combined for pcregrep, it printed a blank
595        line for every non-matching line. GNU grep prints nothing, and pcregrep now
596        does the same. The return code can be used to tell if there were any
597        non-matching lines.
599    14. Added --file-offsets and --line-offsets to pcregrep.
601    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
602        infinitely looping recursion. The bug was that positive lookaheads were not
603        being skipped when checking for a possible empty match (negative lookaheads
604        and both kinds of lookbehind were skipped).
606    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
607        inclusion of <windows.h> to before rather than after the definition of
608        INVALID_FILE_ATTRIBUTES (patch from David Byron).
610    17. Specifying a possessive quantifier with a specific limit for a Unicode
611        character property caused pcre_compile() to compile bad code, which led at
612        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
613        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
614        caused the error; without that there was no problem.
616    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
618    19. Added --enable-pcretest-libreadline.
620    20. In pcrecpp.cc, the variable 'count' was incremented twice in
621        RE::GlobalReplace(). As a result, the number of replacements returned was
622        double what it should be. I removed one of the increments, but Craig sent a
623        later patch that removed the other one (the right fix) and added unit tests
624        that check the return values (which was not done before).
626    21. Several CMake things:
628        (1) Arranged that, when cmake is used on Unix, the libraries end up with
629            the names libpcre and libpcreposix, not just pcre and pcreposix.
631        (2) The above change means that pcretest and pcregrep are now correctly
632            linked with the newly-built libraries, not previously installed ones.
636    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
637        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
638        UTF-8 newline character). The key issue is that the pattern starts .*;
639        this means that the match must be either at the beginning, or after a
640        newline. The bug was in the code for advancing after a failed match and
641        checking that the new position followed a newline. It was not taking
642        account of UTF-8 characters correctly.
644    23. PCRE was behaving differently from Perl in the way it recognized POSIX
645        character classes. PCRE was not treating the sequence [:...:] as a
646        character class unless the ... were all letters. Perl, however, seems to
647        allow any characters between [: and :], though of course it rejects as
648        unknown any "names" that contain non-letters, because all the known class
649        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
650        for example, whereas PCRE did not - it did not recognize a POSIX character
651        class. This seemed a bit dangerous, so the code has been changed to be
652        closer to Perl. The behaviour is not identical to Perl, because PCRE will
653        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
654        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
655        Perl does, and where it didn't before.
657    24. Rewrite so as to remove the single use of %n from pcregrep because in some
658        Windows environments %n is disabled by default.
661    Version 7.4 21-Sep-07
662    ---------------------
664    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
665        means that a class such as [\s] counted as "explicit reference to CR or
666        LF". That isn't really right - the whole point of the change was to try to
667        help when there was an actual mention of one of the two characters. So now
668        the change happens only if \r or \n (or a literal CR or LF) character is
669        encountered.
671    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
672        of both had grown to the point where there were only 3 bits left.
673        Fortunately, there was spare space in the data structure, and so I have
674        moved the internal flags into a new 16-bit field to free up more option
675        bits.
677    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
678        but did not set the internal JCHANGED flag - either of these is enough to
679        control the way the "get" function works - but the PCRE_INFO_JCHANGED
680        facility is supposed to tell if (?J) was ever used, so now (?J) at the
681        start sets both bits.
683    4.  Added options (at build time, compile time, exec time) to change \R from
684        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
686    5.  doc/pcresyntax.html was missing from the distribution.
688    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
689        compatibility, even though it is no longer used.
691    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
692        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
693        windows.h file is present (where different names are used). [This was
694        reversed later after testing - see 16 below.]
696    8.  Changed all #include <config.h> to #include "config.h". There were also
697        some further <pcre.h> cases that I changed to "pcre.h".
699    9.  When pcregrep was used with the --colour option, it missed the line ending
700        sequence off the lines that it output.
702    10. It was pointed out to me that arrays of string pointers cause lots of
703        relocations when a shared library is dynamically loaded. A technique of
704        using a single long string with a table of offsets can drastically reduce
705        these. I have refactored PCRE in four places to do this. The result is
706        dramatic:
708          Originally:                          290
709          After changing UCP table:            187
710          After changing error message table:   43
711          After changing table of "verbs"       36
712          After changing table of Posix names   22
714        Thanks to the folks working on Gregex for glib for this insight.
716    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
717        unicode-properties was also set.
719    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
721    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
722        checked only for CRLF.
724    14. Added casts to pcretest.c to avoid compiler warnings.
726    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
728    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
729        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
730        entirely. This removes changes made in 7 above.
732    17. The CMake files have been updated, and there is now more information about
733        building with CMake in the NON-UNIX-USE document.
736    Version 7.3 28-Aug-07
737    ---------------------
739     1. In the rejigging of the build system that eventually resulted in 7.1, the
740        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
741        brackets there is not right, since it causes compilers to look for an
742        installed pcre.h, not the version that is in the source that is being
743        compiled (which of course may be different). I have changed it back to:
745          #include "pcre.h"
747        I have a vague recollection that the change was concerned with compiling in
748        different directories, but in the new build system, that is taken care of
749        by the VPATH setting the Makefile.
751     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
752        when the subject happened to end in the byte 0x85 (e.g. if the last
753        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
754        characters but of course it shouldn't be taken as a newline when it is part
755        of another character. The bug was that, for an unlimited repeat of . in
756        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
757        characters when looking for a newline.
759     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
761     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
762        in debug output.
764     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
765        long printing in the pcrecpp unittest when running under MinGW.
767     6. ESC_K was left out of the EBCDIC table.
769     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
770        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
771        limit also applies to "virtual nesting" when a pattern is recursive, and in
772        this case 1000 isn't so big. I have been able to remove this limit at the
773        expense of backing off one optimization in certain circumstances. Normally,
774        when pcre_exec() would call its internal match() function recursively and
775        immediately return the result unconditionally, it uses a "tail recursion"
776        feature to save stack. However, when a subpattern that can match an empty
777        string has an unlimited repetition quantifier, it no longer makes this
778        optimization. That gives it a stack frame in which to save the data for
779        checking that an empty string has been matched. Previously this was taken
780        from the 1000-entry workspace that had been reserved. So now there is no
781        explicit limit, but more stack is used.
783     8. Applied Daniel's patches to solve problems with the import/export magic
784        syntax that is required for Windows, and which was going wrong for the
785        pcreposix and pcrecpp parts of the library. These were overlooked when this
786        problem was solved for the main library.
788     9. There were some crude static tests to avoid integer overflow when computing
789        the size of patterns that contain repeated groups with explicit upper
790        limits. As the maximum quantifier is 65535, the maximum group length was
791        set at 30,000 so that the product of these two numbers did not overflow a
792        32-bit integer. However, it turns out that people want to use groups that
793        are longer than 30,000 bytes (though not repeat them that many times).
794        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
795        made it possible to implement the integer overflow checks in a much more
796        dynamic way, which I have now done. The artificial limitation on group
797        length has been removed - we now have only the limit on the total length of
798        the compiled pattern, which depends on the LINK_SIZE setting.
800    10. Fixed a bug in the documentation for get/copy named substring when
801        duplicate names are permitted. If none of the named substrings are set, the
802        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
803        empty string.
805    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
806        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
807        because the ] is interpreted as the first data character and the
808        terminating ] is not found. PCRE has been made compatible with Perl in this
809        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
810        cause memory overwriting.
812    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
813        string has been matched (to stop an infinite loop). It was not recognizing
814        a conditional subpattern that could match an empty string if that
815        subpattern was within another subpattern. For example, it looped when
816        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
817        condition was not nested. This bug has been fixed.
819    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
820        past the start of the subject in the presence of bytes with the top bit
821        set, for example "\x8aBCD".
823    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
824        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
826    14. Optimized (?!) to (*FAIL).
828    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
829        This restricts code points to be within the range 0 to 0x10FFFF, excluding
830        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
831        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
832        does: it's just the validity check that is more restrictive.
834    16. Inserted checks for integer overflows during escape sequence (backslash)
835        processing, and also fixed erroneous offset values for syntax errors during
836        backslash processing.
838    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
839        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
841    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
842        caused an overrun.
844    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
845        something other than just ASCII characters) inside a group that had an
846        unlimited repeat caused a loop at compile time (while checking to see
847        whether the group could match an empty string).
849    20. Debugging a pattern containing \p or \P could cause a crash. For example,
850        [\P{Any}] did so. (Error in the code for printing property names.)
852    21. An orphan \E inside a character class could cause a crash.
854    22. A repeated capturing bracket such as (A)? could cause a wild memory
855        reference during compilation.
857    23. There are several functions in pcre_compile() that scan along a compiled
858        expression for various reasons (e.g. to see if it's fixed length for look
859        behind). There were bugs in these functions when a repeated \p or \P was
860        present in the pattern. These operators have additional parameters compared
861        with \d, etc, and these were not being taken into account when moving along
862        the compiled data. Specifically:
864        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
865            length.
867        (b) An item such as \pL+ within a repeated group could cause crashes or
868            loops.
870        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
871            "reference to non-existent subpattern" error.
873        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
875    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
876        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
878    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
880    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
881        character were causing crashes (broken optimization).
883    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
884        \p or \P) caused a compile-time loop.
886    28. More problems have arisen in unanchored patterns when CRLF is a valid line
887        break. For example, the unstudied pattern [\r\n]A does not match the string
888        "\r\nA" because change 7.0/46 below moves the current point on by two
889        characters after failing to match at the start. However, the pattern \nA
890        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
891        the same is true. There doesn't seem any very clean way out of this, but
892        what I have chosen to do makes the common cases work: PCRE now takes note
893        of whether there can be an explicit match for \r or \n anywhere in the
894        pattern, and if so, 7.0/46 no longer applies. As part of this change,
895        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
896        pattern has explicit CR or LF references.
898    29. Added (*CR) etc for changing newline setting at start of pattern.
901    Version 7.2 19-Jun-07
902    ---------------------
904     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
905        which is apparently normally available under Windows.
907     2. Re-jig the pcregrep tests with different newline settings in an attempt
908        to make them independent of the local environment's newline setting.
910     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
912     4. Some of the "internals" tests were previously cut out when the link size
913        was not 2, because the output contained actual offsets. The recent new
914        "Z" feature of pcretest means that these can be cut out, making the tests
915        usable with all link sizes.
917     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
918        stack recursion. This gives a massive performance boost under BSD, but just
919        a small improvement under Linux. However, it saves one field in the frame
920        in all cases.
922     6. Added more features from the forthcoming Perl 5.10:
924        (a) (?-n) (where n is a string of digits) is a relative subroutine or
925            recursion call. It refers to the nth most recently opened parentheses.
927        (b) (?+n) is also a relative subroutine call; it refers to the nth next
928            to be opened parentheses.
930        (c) Conditions that refer to capturing parentheses can be specified
931            relatively, for example, (?(-2)... or (?(+3)...
933        (d) \K resets the start of the current match so that everything before
934            is not part of it.
936        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
938        (f) \g{name} is another synonym - part of Perl 5.10's unification of
939            reference syntax.
941        (g) (?| introduces a group in which the numbering of parentheses in each
942            alternative starts with the same number.
944        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
946     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
949     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
950        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
951        for detecting groups that can match an empty string.
953     9. A pattern with a very large number of alternatives (more than several
954        hundred) was running out of internal workspace during the pre-compile
955        phase, where pcre_compile() figures out how much memory will be needed. A
956        bit of new cunning has reduced the workspace needed for groups with
957        alternatives. The 1000-alternative test pattern now uses 12 bytes of
958        workspace instead of running out of the 4096 that are available.
960    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
962    11. Applied patch from Google to remove an optimization that didn't quite work.
963        The report of the bug said:
965          pcrecpp::RE("a*").FullMatch("aaa") matches, while
966          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
967          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
969    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
970        it matched the wrong number of bytes.
973    Version 7.1 24-Apr-07
974    ---------------------
976     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
977        that is more "standard", making use of automake and other Autotools. There
978        is some re-arrangement of the files and adjustment of comments consequent
979        on this.
981     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
982        for recursive directory scanning broke on some systems because the files
983        are not scanned in any specific order and on different systems the order
984        was different. A call to "sort" has been inserted into RunGrepTest for the
985        approprate test as a short-term fix. In the longer term there may be an
986        alternative.
988     3. I had an email from Eric Raymond about problems translating some of PCRE's
989        man pages to HTML (despite the fact that I distribute HTML pages, some
990        people do their own conversions for various reasons). The problems
991        concerned the use of low-level troff macros .br and .in. I have therefore
992        removed all such uses from the man pages (some were redundant, some could
993        be replaced by .nf/.fi pairs). The 132html script that I use to generate
994        HTML has been updated to handle .nf/.fi and to complain if it encounters
995        .br or .in.
997     4. Updated comments in configure.ac that get placed in config.h.in and also
998        arranged for config.h to be included in the distribution, with the name
999        config.h.generic, for the benefit of those who have to compile without
1000        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1002     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1003        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1004        makevp.bat for the current PCRE, using the additional files
1005        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1007     6. A Windows user reported a minor discrepancy with test 2, which turned out
1008        to be caused by a trailing space on an input line that had got lost in his
1009        copy. The trailing space was an accident, so I've just removed it.
1011     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1012        that is needed.
1014     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1015        as "const" (a) because they are and (b) because it helps the PHP
1016        maintainers who have recently made a script to detect big data structures
1017        in the php code that should be moved to the .rodata section. I remembered
1018        to update Builducptable as well, so it won't revert if ucptable.h is ever
1019        re-created.
1021     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1022        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1023        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1024        support is not required. This saves 1.5-2K of code, which is important in
1025        some applications.
1027        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1028        so as not to refer to the tables, even though these functions will never be
1029        called when UTF-8 support is disabled. Otherwise there are problems with a
1030        shared library.
1032    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1034        (a) It was defining its arguments as char * instead of void *.
1036        (b) It was assuming that all moves were upwards in memory; this was true
1037            a long time ago when I wrote it, but is no longer the case.
1039        The emulated memove() is provided for those environments that have neither
1040        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1041        is clearly not the case, as these two bugs were recently reported.
1043    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1044        and Detrail to create the HTML documentation, the .txt form of the man
1045        pages, and it removes trailing spaces from listed files. It also creates
1046        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1047        case, it wraps all the #defines with #ifndefs. This script should be run
1048        before "make dist".
1050    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1051        with Unicode property support.
1053        (a) For a maximizing quantifier, if the two different cases of the
1054            character were of different lengths in their UTF-8 codings (there are
1055            some cases like this - I found 11), and the matching function had to
1056            back up over a mixture of the two cases, it incorrectly assumed they
1057            were both the same length.
1059        (b) When PCRE was configured to use the heap rather than the stack for
1060            recursion during matching, it was not correctly preserving the data for
1061            the other case of a UTF-8 character when checking ahead for a match
1062            while processing a minimizing repeat. If the check also involved
1063            matching a wide character, but failed, corruption could cause an
1064            erroneous result when trying to check for a repeat of the original
1065            character.
1067    13. Some tidying changes to the testing mechanism:
1069        (a) The RunTest script now detects the internal link size and whether there
1070            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1071            values substituted by "configure". (The RunGrepTest script already did
1072            this for UTF-8.) The configure.ac script no longer substitutes the
1073            relevant variables.
1075        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1076            with length and offset values. This means that the output is different
1077            for different internal link sizes. Test 2 is skipped for link sizes
1078            other than 2 because of this, bypassing the problem. Unfortunately,
1079            there was also a test in test 3 (the locale tests) that used /B and
1080            failed for link sizes other than 2. Rather than cut the whole test out,
1081            I have added a new /Z option to pcretest that replaces the length and
1082            offset values with spaces. This is now used to make test 3 independent
1083            of link size. (Test 2 will be tidied up later.)
1085    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1086        segmentation fault instead of returning the appropriate error message.
1088    15. In multiline mode when the newline sequence was set to "any", the pattern
1089        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1090        This doesn't seem right; it now treats the CRLF combination as the line
1091        ending, and so does not match in that case. It's only a pattern such as ^$
1092        that would hit this one: something like ^ABC$ would have failed after \r
1093        and then tried again after \r\n.
1095    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1096        in an attempt to make files that differ only in their line terminators
1097        compare equal. This works on Linux.
1099    17. Under certain error circumstances pcregrep might try to free random memory
1100        as it exited. This is now fixed, thanks to valgrind.
1102    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1103        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1104        was because its rules for how to advance for /g after matching an empty
1105        string at the end of a line did not allow for this case. They now check for
1106        it specially.
1108    20. pcretest is supposed to handle patterns and data of any length, by
1109        extending its buffers when necessary. It was getting this wrong when the
1110        buffer for a data line had to be extended.
1112    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1113        CRLF as a newline sequence.
1115    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1116        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1117        I have nevertheless tidied it up.
1119    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1121    24. Added a man page for pcre-config.
1124    Version 7.0 19-Dec-06
1125    ---------------------
1127     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1128        moving to gcc 4.1.1.
1130     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1131        sys/time.h, which is documented as needed for this function. It doesn't
1132        seem to matter on Linux, but it showed up on some releases of OS X.
1134     3. It seems that there are systems where bytes whose values are greater than
1135        127 match isprint() in the "C" locale. The "C" locale should be the
1136        default when a C program starts up. In most systems, only ASCII printing
1137        characters match isprint(). This difference caused the output from pcretest
1138        to vary, making some of the tests fail. I have changed pcretest so that:
1140        (a) When it is outputting text in the compiled version of a pattern, bytes
1141            other than 32-126 are always shown as hex escapes.
1143        (b) When it is outputting text that is a matched part of a subject string,
1144            it does the same, unless a different locale has been set for the match
1145            (using the /L modifier). In this case, it uses isprint() to decide.
1147     4. Fixed a major bug that caused incorrect computation of the amount of memory
1148        required for a compiled pattern when options that changed within the
1149        pattern affected the logic of the preliminary scan that determines the
1150        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1151        that the computed length was too small. The symptoms of this bug were
1152        either the PCRE error "internal error: code overflow" from pcre_compile(),
1153        or a glibc crash with a message such as "pcretest: free(): invalid next
1154        size (fast)". Examples of patterns that provoked this bug (shown in
1155        pcretest format) are:
1157          /(?-x: )/x
1158          /(?x)(?-x: \s*#\s*)/
1159          /((?i)[\x{c0}])/8
1160          /(?i:[\x{c0}])/8
1162        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1163        is now done differently.
1165     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1166        wrapper classes; (b) implement a new function in the C++ scanner that is
1167        more efficient than the old way of doing things because it avoids levels of
1168        recursion in the regex matching; (c) add a paragraph to the documentation
1169        for the FullMatch() function.
1171     6. The escape sequence \n was being treated as whatever was defined as
1172        "newline". Not only was this contrary to the documentation, which states
1173        that \n is character 10 (hex 0A), but it also went horribly wrong when
1174        "newline" was defined as CRLF. This has been fixed.
1176     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1177        was being set to -1 for the "end of line" case (supposedly a value that no
1178        character can have). Though this value is never used (the check for end of
1179        line is "zero bytes in current character"), it caused compiler complaints.
1180        I've changed it to 0xffffffff.
1182     8. In pcre_version.c, the version string was being built by a sequence of
1183        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1184        string (as it is for production releases) called a macro with an empty
1185        argument. The C standard says the result of this is undefined. The gcc
1186        compiler treats it as an empty string (which was what was wanted) but it is
1187        reported that Visual C gives an error. The source has been hacked around to
1188        avoid this problem.
1190     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1191        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1192        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1193        of them did).
1195    10. Originally, pcretest opened its input and output without "b"; then I was
1196        told that "b" was needed in some environments, so it was added for release
1197        5.0 to both the input and output. (It makes no difference on Unix-like
1198        systems.) Later I was told that it is wrong for the input on Windows. I've
1199        now abstracted the modes into two macros, to make it easier to fiddle with
1200        them, and removed "b" from the input mode under Windows.
1202    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1204    12. Added -help and --help to pcretest as an official way of being reminded
1205        of the options.
1207    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1208        and pcrecpp.cc because they annoy compilers at high warning levels.
1210    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1212    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1213        scripts are not C programs :-) and which was not noticed because it works
1214        on Linux.
1216    16. pcretest is supposed to handle any length of pattern and data line (as one
1217        line or as a continued sequence of lines) by extending its input buffer if
1218        necessary. This feature was broken for very long pattern lines, leading to
1219        a string of junk being passed to pcre_compile() if the pattern was longer
1220        than about 50K.
1222    17. I have done a major re-factoring of the way pcre_compile() computes the
1223        amount of memory needed for a compiled pattern. Previously, there was code
1224        that made a preliminary scan of the pattern in order to do this. That was
1225        OK when PCRE was new, but as the facilities have expanded, it has become
1226        harder and harder to keep it in step with the real compile phase, and there
1227        have been a number of bugs (see for example, 4 above). I have now found a
1228        cunning way of running the real compile function in a "fake" mode that
1229        enables it to compute how much memory it would need, while actually only
1230        ever using a few hundred bytes of working memory and without too many
1231        tests of the mode. This should make future maintenance and development
1232        easier. A side effect of this work is that the limit of 200 on the nesting
1233        depth of parentheses has been removed (though this was never a serious
1234        limitation, I suspect). However, there is a downside: pcre_compile() now
1235        runs more slowly than before (30% or more, depending on the pattern). I
1236        hope this isn't a big issue. There is no effect on runtime performance.
1238    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1239        newline (only possible for the last line of a file) and it was a
1240        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1242    19. Added additional timing features to pcretest. (1) The -tm option now times
1243        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1244        separate command line item, by a number that specifies the number of
1245        repeats to use when timing. The default is 50000; this gives better
1246        precision, but takes uncomfortably long for very large patterns.
1248    20. Extended pcre_study() to be more clever in cases where a branch of a
1249        subpattern has no definite first character. For example, (a*|b*)[cd] would
1250        previously give no result from pcre_study(). Now it recognizes that the
1251        first character must be a, b, c, or d.
1253    21. There was an incorrect error "recursive call could loop indefinitely" if
1254        a subpattern (or the entire pattern) that was being tested for matching an
1255        empty string contained only one non-empty item after a nested subpattern.
1256        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1257        incorrectly, because the \d was being skipped in the check.
1259    22. The pcretest program now has a new pattern option /B and a command line
1260        option -b, which is equivalent to adding /B to every pattern. This causes
1261        it to show the compiled bytecode, without the additional information that
1262        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1263        is the same as /B/I).
1265    23. A new optimization is now able automatically to treat some sequences such
1266        as a*b as a*+b. More specifically, if something simple (such as a character
1267        or a simple class like \d) has an unlimited quantifier, and is followed by
1268        something that cannot possibly match the quantified thing, the quantifier
1269        is automatically "possessified".
1271    24. A recursive reference to a subpattern whose number was greater than 39
1272        went wrong under certain circumstances in UTF-8 mode. This bug could also
1273        have affected the operation of pcre_study().
1275    25. Realized that a little bit of performance could be had by replacing
1276        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1278    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1280    27. Possessive quantifiers such as a++ were previously implemented by turning
1281        them into atomic groups such as ($>a+). Now they have their own opcodes,
1282        which improves performance. This includes the automatically created ones
1283        from 23 above.
1285    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1286        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1287        the first matched character to be a colon. This applied both to named and
1288        numbered groups.
1290    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1292    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1293        building PCRE on Windows easier, so I have included it in the distribution.
1295    31. There is now a check in pcretest against a ridiculously large number being
1296        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1297        loop, the loop is abandoned.
1299    32. Forward references to subpatterns in conditions such as (?(2)...) where
1300        subpattern 2 is defined later cause pcre_compile() to search forwards in
1301        the pattern for the relevant set of parentheses. This search went wrong
1302        when there were unescaped parentheses in a character class, parentheses
1303        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1305    33. "Subroutine" calls and backreferences were previously restricted to
1306        referencing subpatterns earlier in the regex. This restriction has now
1307        been removed.
1309    34. Added a number of extra features that are going to be in Perl 5.10. On the
1310        whole, these are just syntactic alternatives for features that PCRE had
1311        previously implemented using the Python syntax or my own invention. The
1312        other formats are all retained for compatibility.
1314        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1315            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1316            also .NET compatible.
1318        (b) A recursion or subroutine call to a named group can now be defined as
1319            (?&name) as well as (?P>name).
1321        (c) A backreference to a named group can now be defined as \k<name> or
1322            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1323            5.10, are also .NET compatible.
1325        (d) A conditional reference to a named group can now use the syntax
1326            (?(<name>) or (?('name') as well as (?(name).
1328        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1329            groups (named and numbered) that are never evaluated inline, but can be
1330            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1331            is always false. There may be only one alternative in such a group.
1333        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1334            as the simple (?(R). The condition is true only if the most recent
1335            recursion is that of the given number or name. It does not search out
1336            through the entire recursion stack.
1338        (g) The escape \gN or \g{N} has been added, where N is a positive or
1339            negative number, specifying an absolute or relative reference.
1341    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1342        some "unreachable code" warnings.
1344    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1345        things, this adds five new scripts.
1347    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1348        There were also incompatibilities regarding the handling of \Q..\E inside
1349        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1350        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1352    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1353        matches an empty string, and forcibly breaks the loop. There were bugs in
1354        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1355        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1356        separate and independent bugs (that affected different cases) have been
1357        fixed.
1359    39. Refactored the code to abolish the use of different opcodes for small
1360        capturing bracket numbers. This is a tidy that I avoided doing when I
1361        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1362        The new approach is not only tidier, it makes it possible to reduce the
1363        memory needed to fix the previous bug (38).
1365    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1366        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1367        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1368        mode.
1370    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1371        report.
1373    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1374        copy construction and assignment in the C++ wrapper.
1376    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1377        couple of bugs that could have given wrong results in the "--newline=crlf"
1378        case.
1380    44. Added a number of casts and did some reorganization of signed/unsigned int
1381        variables following suggestions from Dair Grant. Also renamed the variable
1382        "this" as "item" because it is a C++ keyword.
1384    45. Arranged for dftables to add
1386          #include "pcre_internal.h"
1388        to pcre_chartables.c because without it, gcc 4.x may remove the array
1389        definition from the final binary if PCRE is built into a static library and
1390        dead code stripping is activated.
1392    46. For an unanchored pattern, if a match attempt fails at the start of a
1393        newline sequence, and the newline setting is CRLF or ANY, and the next two
1394        characters are CRLF, advance by two characters instead of one.
1397    Version 6.7 04-Jul-06
1398    ---------------------
1400     1. In order to handle tests when input lines are enormously long, pcretest has
1401        been re-factored so that it automatically extends its buffers when
1402        necessary. The code is crude, but this _is_ just a test program. The
1403        default size has been increased from 32K to 50K.
1405     2. The code in pcre_study() was using the value of the re argument before
1406        testing it for NULL. (Of course, in any sensible call of the function, it
1407        won't be NULL.)
1409     3. The memmove() emulation function in pcre_internal.h, which is used on
1410        systems that lack both memmove() and bcopy() - that is, hardly ever -
1411        was missing a "static" storage class specifier.
1413     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1414        containing an extended class (one that cannot be represented by a bitmap
1415        because it contains high-valued characters or Unicode property items, e.g.
1416        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1417        pattern, but PCRE should not loop if you do not (it no longer does).
1418        [Detail: two cases were found: (a) a repeated subpattern containing an
1419        extended class; (b) a recursive reference to a subpattern that followed a
1420        previous extended class. It wasn't skipping over the extended class
1421        correctly when UTF-8 mode was not set.]
1423     5. A negated single-character class was not being recognized as fixed-length
1424        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1425        compile error "lookbehind assertion is not fixed length".
1427     6. The RunPerlTest auxiliary script was showing an unexpected difference
1428        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1429        write a Perl script that can interpret lines of an input file either as
1430        byte characters or as UTF-8, which is what "perltest" was being required to
1431        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1432        can't do is switch easily at run time between having the "use utf8;" pragma
1433        or not. In the end, I fudged it by using the RunPerlTest script to insert
1434        "use utf8;" explicitly for the UTF-8 tests.
1436     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1437        the end of the subject string, contrary to the documentation and to what
1438        Perl does. This was true of both matching functions. Now it matches only at
1439        the start of the subject and immediately after *internal* newlines.
1441     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1442        a pointer to an int instead of a pointer to an unsigned long int. This
1443        caused problems on 64-bit systems.
1445     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1446        instance of the 'standard' template library not being so standard".
1448    10. There was no check on the number of named subpatterns nor the maximum
1449        length of a subpattern name. The product of these values is used to compute
1450        the size of the memory block for a compiled pattern. By supplying a very
1451        long subpattern name and a large number of named subpatterns, the size
1452        computation could be caused to overflow. This is now prevented by limiting
1453        the length of names to 32 characters, and the number of named subpatterns
1454        to 10,000.
1456    11. Subpatterns that are repeated with specific counts have to be replicated in
1457        the compiled pattern. The size of memory for this was computed from the
1458        length of the subpattern and the repeat count. The latter is limited to
1459        65535, but there was no limit on the former, meaning that integer overflow
1460        could in principle occur. The compiled length of a repeated subpattern is
1461        now limited to 30,000 bytes in order to prevent this.
1463    12. Added the optional facility to have named substrings with the same name.
1465    13. Added the ability to use a named substring as a condition, using the
1466        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1467        are numbers (not recommended). Forward references are permitted.
1469    14. Added forward references in named backreferences (if you see what I mean).
1471    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1472        pattern could run off the end of the subject. For example, the pattern
1473        "(?s)(.{1,5})"8 did this with the subject "ab".
1475    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1476        PCRE_CASELESS was set when matching characters that were quantified with ?
1477        or *.
1479    17. A character class other than a single negated character that had a minimum
1480        but no maximum quantifier - for example [ab]{6,} - was not handled
1481        correctly by pce_dfa_exec(). It would match only one character.
1483    18. A valid (though odd) pattern that looked like a POSIX character
1484        class but used an invalid character after [ (for example [[,abc,]]) caused
1485        pcre_compile() to give the error "Failed: internal error: code overflow" or
1486        in some cases to crash with a glibc free() error. This could even happen if
1487        the pattern terminated after [[ but there just happened to be a sequence of
1488        letters, a binary zero, and a closing ] in the memory that followed.
1490    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1491        over the years. Originally (before any Unicode support), just the bottom 8
1492        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1493        output from "man perlunicode" includes this:
1495          The regular expression compiler produces polymorphic opcodes.  That
1496          is, the pattern adapts to the data and automatically switches to
1497          the Unicode character scheme when presented with Unicode data--or
1498          instead uses a traditional byte scheme when presented with byte
1499          data.
1501        Sadly, a wide octal escape does not cause a switch, and in a string with
1502        no other multibyte characters, these octal escapes are treated as before.
1503        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1504        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1505        Unicode string.
1507        I have not perpetrated such confusion in PCRE. Up till now, it took just
1508        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1509        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1510        translate to the appropriate multibyte character.
1512    29. Applied some refactoring to reduce the number of warnings from Microsoft
1513        and Borland compilers. This has included removing the fudge introduced
1514        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1515        a warning about an unused variable.
1517    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1518        characters since release 4.0, because Perl (from release 5.004) does not.
1519        [Or at least, is documented not to: some releases seem to be in conflict
1520        with the documentation.] However, when a pattern was studied with
1521        pcre_study() and all its branches started with \s, PCRE still included VT
1522        as a possible starting character. Of course, this did no harm; it just
1523        caused an unnecessary match attempt.
1525    22. Removed a now-redundant internal flag bit that recorded the fact that case
1526        dependency changed within the pattern. This was once needed for "required
1527        byte" processing, but is no longer used. This recovers a now-scarce options
1528        bit. Also moved the least significant internal flag bit to the most-
1529        significant bit of the word, which was not previously used (hangover from
1530        the days when it was an int rather than a uint) to free up another bit for
1531        the future.
1533    23. Added support for CRLF line endings as well as CR and LF. As well as the
1534        default being selectable at build time, it can now be changed at runtime
1535        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1536        specify that it is scanning data with non-default line endings.
1538    24. Changed the definition of CXXLINK to make it agree with the definition of
1539        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1541    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1542        recursions. This makes a big different to stack usage for some patterns.
1544    26. If a subpattern containing a named recursion or subroutine reference such
1545        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1546        the space required for the compiled pattern went wrong and gave too small a
1547        value. Depending on the environment, this could lead to "Failed: internal
1548        error: code overflow at offset 49" or "glibc detected double free or
1549        corruption" errors.
1551    27. Applied patches from Google (a) to support the new newline modes and (b) to
1552        advance over multibyte UTF-8 characters in GlobalReplace.
1554    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1555        difference for some implementation of PCRE in some Windows version.
1557    29. Added some extra testing facilities to pcretest:
1559        \q<number>   in a data line sets the "match limit" value
1560        \Q<number>   in a data line sets the "match recursion limt" value
1561        -S <number>  sets the stack size, where <number> is in megabytes
1563        The -S option isn't available for Windows.
1566    Version 6.6 06-Feb-06
1567    ---------------------
1569     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1570        in pcreposix.h. I have copied the definition from pcre.h.
1572     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1573        because pcre.h is no longer a built file.
1575     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1576        not normally included in the compiled code.
1579  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1580  ---------------------  ---------------------

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