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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.01 11-Dec-09
5    ----------------------
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
12    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13        the pattern is reset in the first branch, pcre_compile() failed with
14        "internal error: code overflow at offset...". This happened only when
15        the reset was to the original external option setting. (An optimization
16        abstracts leading options settings into an external setting, which was the
17        cause of this.)
19    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21        assertion pattern did not match (meaning that the assertion was true), it
22        was incorrectly treated as false if the SKIP had been reached during the
23        matching. This also applied to assertions used as conditions.
25    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
26        assertion subpattern, including such a pattern used as a condition,
27        unpredictable results occurred, instead of the error return
30    5.  The C++ GlobalReplace function was not working like Perl for the special
31        situation when an empty string is matched. It now does the fancy magic
32        stuff that is necessary.
34    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
35        removed. (These were left over from very, very early versions of PCRE.)
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
40        (a) Change DEBUG to PCRE_DEBUG.
42        (b) In pcre_compile(), rename the member of the "branch_chain" structure
43            called "current" as "current_branch", to prevent a collision with the
44            Linux macro when compiled as a kernel module.
46        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
47            prevent a collision with the Linux macro when compiled as a kernel
48            module.
50    8.  In pcre_compile() there are some checks for integer overflows that used to
51        cast potentially large values to (double). This has been changed to that
52        when building, a check for int64_t is made, and if it is found, it is used
53        instead, thus avoiding the use of floating point arithmetic. (There is no
54        other use of FP in PCRE.) If int64_t is not found, the fallback is to
55        double.
57    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
58        2005 (difference between two addresses compared to an unsigned value).
60    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
61        custom one, because of the following reported problem in Windows:
63          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
64            under Win32.
65          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
66            therefore missing the function definition.
67          - The compiler thus generates a "C" signature for the test function.
68          - The linker fails to find the "C" function.
69          - PCRE fails to configure if asked to do so against libbz2.
71    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
72        messages were output:
74          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
75          rerunning libtoolize, to keep the correct libtool macros in-tree.
76          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
78        I have done both of these things.
80    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
81        most of the time, it *can* run out if it is given a pattern that contains a
82        runaway infinite recursion. I updated the discussion in the pcrestack man
83        page.
85    13. Now that we have gone to the x.xx style of version numbers, the minor
86        version may start with zero. Using 08 or 09 is a bad idea because users
87        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
88        interpreted as invalid octal numbers. I've updated the previous comment in
89        configure.ac, and also added a check that gives an error if 08 or 09 are
90        used.
92    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
93        causing partial matching to fail when the end of the subject matched \W
94        in a UTF-8 pattern where \W was quantified with a minimum of 3.
96    15. There were some discrepancies between the declarations in pcre_internal.h
97        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
98        their definitions. The declarations used "const uschar *" and the
99        definitions used USPTR. Even though USPTR is normally defined as "const
100        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
101        reported that: "This difference in casting confuses some C++ compilers, for
102        example, SunCC recognizes above declarations as different functions and
103        generates broken code for hbpcre." I have changed the declarations to use
104        USPTR.
106    16. GNU libtool is named differently on some systems. The autogen.sh script now
107        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
108        (FreeBSD).
112    Version 8.00 19-Oct-09
113    ----------------------
115    1.  The table for translating pcre_compile() error codes into POSIX error codes
116        was out-of-date, and there was no check on the pcre_compile() error code
117        being within the table. This could lead to an OK return being given in
118        error.
120    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
121        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
122        in a Windows environment.
124    3.  The pcregrep --count option prints the count for each file even when it is
125        zero, as does GNU grep. However, pcregrep was also printing all files when
126        --files-with-matches was added. Now, when both options are given, it prints
127        counts only for those files that have at least one match. (GNU grep just
128        prints the file name in this circumstance, but including the count seems
129        more useful - otherwise, why use --count?) Also ensured that the
130        combination -clh just lists non-zero counts, with no names.
132    4.  The long form of the pcregrep -F option was incorrectly implemented as
133        --fixed_strings instead of --fixed-strings. This is an incompatible change,
134        but it seems right to fix it, and I didn't think it was worth preserving
135        the old behaviour.
137    5.  The command line items --regex=pattern and --regexp=pattern were not
138        recognized by pcregrep, which required --regex pattern or --regexp pattern
139        (with a space rather than an '='). The man page documented the '=' forms,
140        which are compatible with GNU grep; these now work.
142    6.  No libpcreposix.pc file was created for pkg-config; there was just
143        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
145    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
146        when UCP support is not needed, by modifying the Python script that
147        generates it from Unicode data files. This should not matter if the module
148        is correctly used as a library, but I received one complaint about 50K of
149        unwanted data. My guess is that the person linked everything into his
150        program rather than using a library. Anyway, it does no harm.
152    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
153        was a minimum greater than 1 for a wide character in a possessive
154        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
155        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
156        character. Chaos in the form of incorrect output or a compiling loop could
157        result.
159    9.  The restrictions on what a pattern can contain when partial matching is
160        requested for pcre_exec() have been removed. All patterns can now be
161        partially matched by this function. In addition, if there are at least two
162        slots in the offset vector, the offset of the earliest inspected character
163        for the match and the offset of the end of the subject are set in them when
164        PCRE_ERROR_PARTIAL is returned.
166    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
167        synonymous with PCRE_PARTIAL, for backwards compatibility, and
168        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
169        and may be more useful for multi-segment matching.
171    11. Partial matching with pcre_exec() is now more intuitive. A partial match
172        used to be given if ever the end of the subject was reached; now it is
173        given only if matching could not proceed because another character was
174        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
175        string "Z", which now yields "no match" instead of "partial match". In the
176        case of pcre_dfa_exec(), "no match" is given if every matching path for the
177        final character ended with (*FAIL).
179    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
180        if the pattern had a "must contain" character that was already found in the
181        earlier partial match, unless partial matching was again requested. For
182        example, with the pattern /dog.(body)?/, the "must contain" character is
183        "g". If the first part-match was for the string "dog", restarting with
184        "sbody" failed. This bug has been fixed.
186    13. The string returned by pcre_dfa_exec() after a partial match has been
187        changed so that it starts at the first inspected character rather than the
188        first character of the match. This makes a difference only if the pattern
189        starts with a lookbehind assertion or \b or \B (\K is not supported by
190        pcre_dfa_exec()). It's an incompatible change, but it makes the two
191        matching functions compatible, and I think it's the right thing to do.
193    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
194        so that the demonstration program is easily available in environments where
195        PCRE has not been installed from source.
197    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
198        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
199        library.
201    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
202        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
203        is not the first non-POSIX option to be added. Clearly some people find
204        these options useful.
206    17. If a caller to the POSIX matching function regexec() passes a non-zero
207        value for nmatch with a NULL value for pmatch, the value of
208        nmatch is forced to zero.
210    18. RunGrepTest did not have a test for the availability of the -u option of
211        the diff command, as RunTest does. It now checks in the same way as
212        RunTest, and also checks for the -b option.
214    19. If an odd number of negated classes containing just a single character
215        interposed, within parentheses, between a forward reference to a named
216        subpattern and the definition of the subpattern, compilation crashed with
217        an internal error, complaining that it could not find the referenced
218        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
219        [The bug was that it was starting one character too far in when skipping
220        over the character class, thus treating the ] as data rather than
221        terminating the class. This meant it could skip too much.]
223    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
224        /g option in pcretest when the pattern contains \K, which makes it possible
225        to have an empty string match not at the start, even when the pattern is
226        anchored. Updated pcretest and pcredemo to use this option.
228    21. If the maximum number of capturing subpatterns in a recursion was greater
229        than the maximum at the outer level, the higher number was returned, but
230        with unset values at the outer level. The correct (outer level) value is
231        now given.
233    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
234        PCRE did not set those parentheses (unlike Perl). I have now found a way to
235        make it do so. The string so far is captured, making this feature
236        compatible with Perl.
238    23. The tests have been re-organized, adding tests 11 and 12, to make it
239        possible to check the Perl 5.10 features against Perl 5.10.
241    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
242        pattern matches a fixed length string. PCRE did not allow this; now it
243        does. Neither allows recursion.
245    25. I finally figured out how to implement a request to provide the minimum
246        length of subject string that was needed in order to match a given pattern.
247        (It was back references and recursion that I had previously got hung up
248        on.) This code has now been added to pcre_study(); it finds a lower bound
249        to the length of subject needed. It is not necessarily the greatest lower
250        bound, but using it to avoid searching strings that are too short does give
251        some useful speed-ups. The value is available to calling programs via
252        pcre_fullinfo().
254    26. While implementing 25, I discovered to my embarrassment that pcretest had
255        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
256        study optimizations had never been tested with that matching function.
257        Oops. What is worse, even when it was passed study data, there was a bug in
258        pcre_dfa_exec() that meant it never actually used it. Double oops. There
259        were also very few tests of studied patterns with pcre_dfa_exec().
261    27. If (?| is used to create subpatterns with duplicate numbers, they are now
262        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
263        on the other side of the coin, they are no longer allowed to have different
264        names, because these cannot be distinguished in PCRE, and this has caused
265        confusion. (This is a difference from Perl.)
267    28. When duplicate subpattern names are present (necessarily with different
268        numbers, as required by 27 above), and a test is made by name in a
269        conditional pattern, either for a subpattern having been matched, or for
270        recursion in such a pattern, all the associated numbered subpatterns are
271        tested, and the overall condition is true if the condition is true for any
272        one of them. This is the way Perl works, and is also more like the way
273        testing by number works.
276    Version 7.9 11-Apr-09
277    ---------------------
279    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
280        (pcretest), all targets were linked against these libraries. This included
281        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
282        libraries. This caused unwanted dependencies to be created. This problem
283        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
284        pcretest is linked with readline.
286    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
287        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
288        moved outside it again, because FALSE and TRUE are already defined in AIX,
289        but BOOL is not.
291    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
292        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
294    4.  The pcregrep documentation said spaces were inserted as well as colons (or
295        hyphens) following file names and line numbers when outputting matching
296        lines. This is not true; no spaces are inserted. I have also clarified the
297        wording for the --colour (or --color) option.
299    5.  In pcregrep, when --colour was used with -o, the list of matching strings
300        was not coloured; this is different to GNU grep, so I have changed it to be
301        the same.
303    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
304        each matching line was coloured. Now it goes on to look for further matches
305        of any of the test patterns, which is the same behaviour as GNU grep.
307    7.  A pattern that could match an empty string could cause pcregrep to loop; it
308        doesn't make sense to accept an empty string match in pcregrep, so I have
309        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
310        seems to be how GNU grep behaves.
312    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
313        start or after a newline", because the conditional assertion was not being
314        correctly handled. The rule now is that both the assertion and what follows
315        in the first alternative must satisfy the test.
317    9.  If auto-callout was enabled in a pattern with a conditional group whose
318        condition was an assertion, PCRE could crash during matching, both with
319        pcre_exec() and pcre_dfa_exec().
321    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
322        used for matching.
324    11. Unicode property support in character classes was not working for
325        characters (bytes) greater than 127 when not in UTF-8 mode.
327    12. Added the -M command line option to pcretest.
329    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
331    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
333    16. Added comments and documentation about mis-use of no_arg in the C++
334        wrapper.
336    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
337        from Martin Jerabek that uses macro names for all relevant character and
338        string constants.
340    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
341        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
342        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
343        these, but not everybody uses configure.
345    19. A conditional group that had only one branch was not being correctly
346        recognized as an item that could match an empty string. This meant that an
347        enclosing group might also not be so recognized, causing infinite looping
348        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
349        with the subject "ab", where knowledge that the repeated group can match
350        nothing is needed in order to break the loop.
352    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
353        exec(), but without supplying a callout function, matching went wrong.
355    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
356        leak if the size of the offset vector was greater than 30. When the vector
357        is smaller, the saved offsets during recursion go onto a local stack
358        vector, but for larger vectors malloc() is used. It was failing to free
359        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
360        error, in fact).
362    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
363        heapframe that is used only when UTF-8 support is enabled. This caused no
364        problem, but was untidy.
366    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
367        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
368        included within another project.
370    24. Steven Van Ingelgem's patches to add more options to the CMake support,
371        slightly modified by me:
373          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
374              not building pcregrep.
376          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
377              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
379    25. Forward references, both numeric and by name, in patterns that made use of
380        duplicate group numbers, could behave incorrectly or give incorrect errors,
381        because when scanning forward to find the reference group, PCRE was not
382        taking into account the duplicate group numbers. A pattern such as
383        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
385    26. Changed a few more instances of "const unsigned char *" to USPTR, making
386        the feature of a custom pointer more persuasive (as requested by a user).
388    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
389        pcretest.c, inside #ifndefs, because it seems they are sometimes already
390        pre-defined.
392    28. Added support for (*UTF8) at the start of a pattern.
394    29. Arrange for flags added by the "release type" setting in CMake to be shown
395        in the configuration summary.
398    Version 7.8 05-Sep-08
399    ---------------------
401    1.  Replaced UCP searching code with optimized version as implemented for Ad
402        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
403        stage table and inline lookup instead of a function, giving speed ups of 2
404        to 5 times on some simple patterns that I tested. Permission was given to
405        distribute the MultiStage2.py script that generates the tables (it's not in
406        the tarball, but is in the Subversion repository).
408    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
409        scripts.
411    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
412        a group with a zero qualifier. The result of the study could be incorrect,
413        or the function might crash, depending on the pattern.
415    4.  Caseless matching was not working for non-ASCII characters in back
416        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
417        It now works when Unicode Property Support is available.
419    5.  In pcretest, an escape such as \x{de} in the data was always generating
420        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
421        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
422        truncation.
424    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
426    7.  Added two (int) casts to pcregrep when printing the difference of two
427        pointers, in case they are 64-bit values.
429    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
430        test 2 if it fails.
432    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
433        and a #define of that name to empty if it is not externally set. This is to
434        allow users of MSVC to set it if necessary.
436    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
437        the convenience functions in the pcre_get.c source file.
439    11. An option change at the start of a pattern that had top-level alternatives
440        could cause overwriting and/or a crash. This command provoked a crash in
441        some environments:
443          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
445        This potential security problem was recorded as CVE-2008-2371.
447    12. For a pattern where the match had to start at the beginning or immediately
448        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
449        pcre_dfa_exec() could read past the end of the passed subject if there was
450        no match. To help with detecting such bugs (e.g. with valgrind), I modified
451        pcretest so that it places the subject at the end of its malloc-ed buffer.
453    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
454        exec() might read past the end of the data buffer in UTF-8 mode.
456    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
457        the data contained the byte 0x85 as part of a UTF-8 character within its
458        first line. This applied both to normal and DFA matching.
460    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
461        /^[^d]*?$/8 failed to match "abc".
463    16. Added a missing copyright notice to pcrecpp_internal.h.
465    17. Make it more clear in the documentation that values returned from
466        pcre_exec() in ovector are byte offsets, not character counts.
468    18. Tidied a few places to stop certain compilers from issuing warnings.
470    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
471        supplied by Stefan Weber. I made a further small update for 7.8 because
472        there is a change of source arrangements: the pcre_searchfuncs.c module is
473        replaced by pcre_ucd.c.
476    Version 7.7 07-May-08
477    ---------------------
479    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
480        a string to a long long, pretend we don't even have a long long." This is
481        done by checking for the strtoq, strtoll, and _strtoi64 functions.
483    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
484        pre-7.6 versions, which defined a global no_arg variable instead of putting
485        it in the RE class. (See also #8 below.)
487    3.  Remove a line of dead code, identified by coverity and reported by Nuno
488        Lopes.
490    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
492        (1) The include/exclude patterns were being applied to the whole pathnames
493            of files, instead of just to the final components.
495        (2) If there was more than one level of directory, the subdirectories were
496            skipped unless they satisfied the include/exclude conditions. This is
497            inconsistent with GNU grep (and could even be seen as contrary to the
498            pcregrep specification - which I improved to make it absolutely clear).
499            The action now is always to scan all levels of directory, and just
500            apply the include/exclude patterns to regular files.
502    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
503        --exclude_dir in the tests to avoid scanning .svn directories.
505    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
506        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
507        doesn't support NULs in patterns.
509    7.  Added some missing "const"s to declarations of static tables in
510        pcre_compile.c and pcre_dfa_exec.c.
512    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
513        caused by fix #2  above. (Subsequently also a second patch to fix the
514        first patch. And a third patch - this was a messy problem.)
516    9.  Applied Craig's patch to remove the use of push_back().
518    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
519        matching function regexec().
521    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
522        which, however, unlike Perl's \g{...}, are subroutine calls, not back
523        references. PCRE supports relative numbers with this syntax (I don't think
524        Oniguruma does).
526    12. Previously, a group with a zero repeat such as (...){0} was completely
527        omitted from the compiled regex. However, this means that if the group
528        was called as a subroutine from elsewhere in the pattern, things went wrong
529        (an internal error was given). Such groups are now left in the compiled
530        pattern, with a new opcode that causes them to be skipped at execution
531        time.
533    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
534        to the way PCRE behaves:
536        (a) A lone ] character is dis-allowed (Perl treats it as data).
538        (b) A back reference to an unmatched subpattern matches an empty string
539            (Perl fails the current match path).
541        (c) A data ] in a character class must be notated as \] because if the
542            first data character in a class is ], it defines an empty class. (In
543            Perl it is not possible to have an empty class.) The empty class []
544            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
545            The negative empty class [^] matches any one character, independently
546            of the DOTALL setting.
548    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
549        non-existent subpattern following a character class starting with ']' and
550        containing () gave an internal compiling error instead of "reference to
551        non-existent subpattern". Fortunately, when the pattern did exist, the
552        compiled code was correct. (When scanning forwards to check for the
553        existencd of the subpattern, it was treating the data ']' as terminating
554        the class, so got the count wrong. When actually compiling, the reference
555        was subsequently set up correctly.)
557    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
558        it was being rejected as not supported by pcre_dfa_exec(), even though
559        other assertions are supported. I have made pcre_dfa_exec() support
560        (*FAIL).
562    16. The implementation of 13c above involved the invention of a new opcode,
563        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
564        cannot be changed at match time, I realized I could make a small
565        improvement to matching performance by compiling OP_ALLANY instead of
566        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
567        on the OP_ANY path.
569    17. Compiling pcretest on Windows with readline support failed without the
570        following two fixes: (1) Make the unistd.h include conditional on
571        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
573    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
574        ncurses library to be included for pcretest when ReadLine support is
575        requested, but also to allow for it to be overridden. This patch came from
576        Daniel Bergström.
578    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
579        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
580        any errors with the current Unicode tables. Thanks to Peter Kankowski for
581        spotting this.
584    Version 7.6 28-Jan-08
585    ---------------------
587    1.  A character class containing a very large number of characters with
588        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
589        overflow.
591    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
592        HAVE_LONG_LONG is not defined.
594    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
595        bring them up to date and include new features. This patch includes:
597        - Fixed PH's badly added libz and libbz2 support.
598        - Fixed a problem with static linking.
599        - Added pcredemo. [But later removed - see 7 below.]
600        - Fixed dftables problem and added an option.
601        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
602            HAVE_LONG_LONG.
603        - Added readline support for pcretest.
604        - Added an listing of the option settings after cmake has run.
606    4.  A user submitted a patch to Makefile that makes it easy to create
607        "pcre.dll" under mingw when using Configure/Make. I added stuff to
608        Makefile.am that cause it to include this special target, without
609        affecting anything else. Note that the same mingw target plus all
610        the other distribution libraries and programs are now supported
611        when configuring with CMake (see 6 below) instead of with
612        Configure/Make.
614    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
615        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
616        exported in the Windows port". It has not yet been confirmed that the patch
617        solves the problem, but it does no harm.
619    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
620        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
621        with CMake, and also correct the comment about stack recursion.
623    7.  Remove the automatic building of pcredemo from the ./configure system and
624        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
625        of a program that users should build themselves after PCRE is installed, so
626        building it automatically is not really right. What is more, it gave
627        trouble in some build environments.
629    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
632    Version 7.5 10-Jan-08
633    ---------------------
635    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
636        values in parens when parsing an RE using the C++ wrapper."
638    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
639        Characters greater than 255 were excluded from the class instead of being
640        included.
642    3.  The same bug as (2) above applied to negated POSIX classes such as
643        [:^space:].
645    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
646        defined or documented. It seems to have been a typo for PCRE_STATIC, so
647        I have changed it.
649    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
650        first named subpattern) and a construct such as (?&a) would reference the
651        first named subpattern whose name started with "a" (in other words, the
652        length check was missing). Both these problems are fixed. "Subpattern name
653        expected" is now given for (?&) (a zero-length name), and this patch also
654        makes it give the same error for \k'' (previously it complained that that
655        was a reference to a non-existent subpattern).
657    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
658        this is right because (?- can be followed by option settings as well as by
659        digits. I have, however, made the messages clearer.
661    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
662        than the number used in the conditional) now cause a compile-time error.
663        This is actually not compatible with Perl, which accepts such patterns, but
664        treats the conditional as always being FALSE (as PCRE used to), but it
665        seems to me that giving a diagnostic is better.
667    8.  Change "alphameric" to the more common word "alphanumeric" in comments
668        and messages.
670    9.  Fix two occurrences of "backslash" in comments that should have been
671        "backspace".
673    10. Remove two redundant lines of code that can never be obeyed (their function
674        was moved elsewhere).
676    11. The program that makes PCRE's Unicode character property table had a bug
677        which caused it to generate incorrect table entries for sequences of
678        characters that have the same character type, but are in different scripts.
679        It amalgamated them into a single range, with the script of the first of
680        them. In other words, some characters were in the wrong script. There were
681        thirteen such cases, affecting characters in the following ranges:
683          U+002b0 - U+002c1
684          U+0060c - U+0060d
685          U+0061e - U+00612
686          U+0064b - U+0065e
687          U+0074d - U+0076d
688          U+01800 - U+01805
689          U+01d00 - U+01d77
690          U+01d9b - U+01dbf
691          U+0200b - U+0200f
692          U+030fc - U+030fe
693          U+03260 - U+0327f
694          U+0fb46 - U+0fbb1
695          U+10450 - U+1049d
697    12. The -o option (show only the matching part of a line) for pcregrep was not
698        compatible with GNU grep in that, if there was more than one match in a
699        line, it showed only the first of them. It now behaves in the same way as
700        GNU grep.
702    13. If the -o and -v options were combined for pcregrep, it printed a blank
703        line for every non-matching line. GNU grep prints nothing, and pcregrep now
704        does the same. The return code can be used to tell if there were any
705        non-matching lines.
707    14. Added --file-offsets and --line-offsets to pcregrep.
709    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
710        infinitely looping recursion. The bug was that positive lookaheads were not
711        being skipped when checking for a possible empty match (negative lookaheads
712        and both kinds of lookbehind were skipped).
714    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
715        inclusion of <windows.h> to before rather than after the definition of
716        INVALID_FILE_ATTRIBUTES (patch from David Byron).
718    17. Specifying a possessive quantifier with a specific limit for a Unicode
719        character property caused pcre_compile() to compile bad code, which led at
720        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
721        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
722        caused the error; without that there was no problem.
724    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
726    19. Added --enable-pcretest-libreadline.
728    20. In pcrecpp.cc, the variable 'count' was incremented twice in
729        RE::GlobalReplace(). As a result, the number of replacements returned was
730        double what it should be. I removed one of the increments, but Craig sent a
731        later patch that removed the other one (the right fix) and added unit tests
732        that check the return values (which was not done before).
734    21. Several CMake things:
736        (1) Arranged that, when cmake is used on Unix, the libraries end up with
737            the names libpcre and libpcreposix, not just pcre and pcreposix.
739        (2) The above change means that pcretest and pcregrep are now correctly
740            linked with the newly-built libraries, not previously installed ones.
744    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
745        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
746        UTF-8 newline character). The key issue is that the pattern starts .*;
747        this means that the match must be either at the beginning, or after a
748        newline. The bug was in the code for advancing after a failed match and
749        checking that the new position followed a newline. It was not taking
750        account of UTF-8 characters correctly.
752    23. PCRE was behaving differently from Perl in the way it recognized POSIX
753        character classes. PCRE was not treating the sequence [:...:] as a
754        character class unless the ... were all letters. Perl, however, seems to
755        allow any characters between [: and :], though of course it rejects as
756        unknown any "names" that contain non-letters, because all the known class
757        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
758        for example, whereas PCRE did not - it did not recognize a POSIX character
759        class. This seemed a bit dangerous, so the code has been changed to be
760        closer to Perl. The behaviour is not identical to Perl, because PCRE will
761        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
762        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
763        Perl does, and where it didn't before.
765    24. Rewrite so as to remove the single use of %n from pcregrep because in some
766        Windows environments %n is disabled by default.
769    Version 7.4 21-Sep-07
770    ---------------------
772    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
773        means that a class such as [\s] counted as "explicit reference to CR or
774        LF". That isn't really right - the whole point of the change was to try to
775        help when there was an actual mention of one of the two characters. So now
776        the change happens only if \r or \n (or a literal CR or LF) character is
777        encountered.
779    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
780        of both had grown to the point where there were only 3 bits left.
781        Fortunately, there was spare space in the data structure, and so I have
782        moved the internal flags into a new 16-bit field to free up more option
783        bits.
785    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
786        but did not set the internal JCHANGED flag - either of these is enough to
787        control the way the "get" function works - but the PCRE_INFO_JCHANGED
788        facility is supposed to tell if (?J) was ever used, so now (?J) at the
789        start sets both bits.
791    4.  Added options (at build time, compile time, exec time) to change \R from
792        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
794    5.  doc/pcresyntax.html was missing from the distribution.
796    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
797        compatibility, even though it is no longer used.
799    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
800        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
801        windows.h file is present (where different names are used). [This was
802        reversed later after testing - see 16 below.]
804    8.  Changed all #include <config.h> to #include "config.h". There were also
805        some further <pcre.h> cases that I changed to "pcre.h".
807    9.  When pcregrep was used with the --colour option, it missed the line ending
808        sequence off the lines that it output.
810    10. It was pointed out to me that arrays of string pointers cause lots of
811        relocations when a shared library is dynamically loaded. A technique of
812        using a single long string with a table of offsets can drastically reduce
813        these. I have refactored PCRE in four places to do this. The result is
814        dramatic:
816          Originally:                          290
817          After changing UCP table:            187
818          After changing error message table:   43
819          After changing table of "verbs"       36
820          After changing table of Posix names   22
822        Thanks to the folks working on Gregex for glib for this insight.
824    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
825        unicode-properties was also set.
827    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
829    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
830        checked only for CRLF.
832    14. Added casts to pcretest.c to avoid compiler warnings.
834    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
836    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
837        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
838        entirely. This removes changes made in 7 above.
840    17. The CMake files have been updated, and there is now more information about
841        building with CMake in the NON-UNIX-USE document.
844    Version 7.3 28-Aug-07
845    ---------------------
847     1. In the rejigging of the build system that eventually resulted in 7.1, the
848        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
849        brackets there is not right, since it causes compilers to look for an
850        installed pcre.h, not the version that is in the source that is being
851        compiled (which of course may be different). I have changed it back to:
853          #include "pcre.h"
855        I have a vague recollection that the change was concerned with compiling in
856        different directories, but in the new build system, that is taken care of
857        by the VPATH setting the Makefile.
859     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
860        when the subject happened to end in the byte 0x85 (e.g. if the last
861        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
862        characters but of course it shouldn't be taken as a newline when it is part
863        of another character. The bug was that, for an unlimited repeat of . in
864        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
865        characters when looking for a newline.
867     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
869     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
870        in debug output.
872     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
873        long printing in the pcrecpp unittest when running under MinGW.
875     6. ESC_K was left out of the EBCDIC table.
877     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
878        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
879        limit also applies to "virtual nesting" when a pattern is recursive, and in
880        this case 1000 isn't so big. I have been able to remove this limit at the
881        expense of backing off one optimization in certain circumstances. Normally,
882        when pcre_exec() would call its internal match() function recursively and
883        immediately return the result unconditionally, it uses a "tail recursion"
884        feature to save stack. However, when a subpattern that can match an empty
885        string has an unlimited repetition quantifier, it no longer makes this
886        optimization. That gives it a stack frame in which to save the data for
887        checking that an empty string has been matched. Previously this was taken
888        from the 1000-entry workspace that had been reserved. So now there is no
889        explicit limit, but more stack is used.
891     8. Applied Daniel's patches to solve problems with the import/export magic
892        syntax that is required for Windows, and which was going wrong for the
893        pcreposix and pcrecpp parts of the library. These were overlooked when this
894        problem was solved for the main library.
896     9. There were some crude static tests to avoid integer overflow when computing
897        the size of patterns that contain repeated groups with explicit upper
898        limits. As the maximum quantifier is 65535, the maximum group length was
899        set at 30,000 so that the product of these two numbers did not overflow a
900        32-bit integer. However, it turns out that people want to use groups that
901        are longer than 30,000 bytes (though not repeat them that many times).
902        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
903        made it possible to implement the integer overflow checks in a much more
904        dynamic way, which I have now done. The artificial limitation on group
905        length has been removed - we now have only the limit on the total length of
906        the compiled pattern, which depends on the LINK_SIZE setting.
908    10. Fixed a bug in the documentation for get/copy named substring when
909        duplicate names are permitted. If none of the named substrings are set, the
910        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
911        empty string.
913    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
914        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
915        because the ] is interpreted as the first data character and the
916        terminating ] is not found. PCRE has been made compatible with Perl in this
917        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
918        cause memory overwriting.
920    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
921        string has been matched (to stop an infinite loop). It was not recognizing
922        a conditional subpattern that could match an empty string if that
923        subpattern was within another subpattern. For example, it looped when
924        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
925        condition was not nested. This bug has been fixed.
927    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
928        past the start of the subject in the presence of bytes with the top bit
929        set, for example "\x8aBCD".
931    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
932        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
934    14. Optimized (?!) to (*FAIL).
936    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
937        This restricts code points to be within the range 0 to 0x10FFFF, excluding
938        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
939        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
940        does: it's just the validity check that is more restrictive.
942    16. Inserted checks for integer overflows during escape sequence (backslash)
943        processing, and also fixed erroneous offset values for syntax errors during
944        backslash processing.
946    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
947        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
949    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
950        caused an overrun.
952    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
953        something other than just ASCII characters) inside a group that had an
954        unlimited repeat caused a loop at compile time (while checking to see
955        whether the group could match an empty string).
957    20. Debugging a pattern containing \p or \P could cause a crash. For example,
958        [\P{Any}] did so. (Error in the code for printing property names.)
960    21. An orphan \E inside a character class could cause a crash.
962    22. A repeated capturing bracket such as (A)? could cause a wild memory
963        reference during compilation.
965    23. There are several functions in pcre_compile() that scan along a compiled
966        expression for various reasons (e.g. to see if it's fixed length for look
967        behind). There were bugs in these functions when a repeated \p or \P was
968        present in the pattern. These operators have additional parameters compared
969        with \d, etc, and these were not being taken into account when moving along
970        the compiled data. Specifically:
972        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
973            length.
975        (b) An item such as \pL+ within a repeated group could cause crashes or
976            loops.
978        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
979            "reference to non-existent subpattern" error.
981        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
983    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
984        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
986    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
988    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
989        character were causing crashes (broken optimization).
991    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
992        \p or \P) caused a compile-time loop.
994    28. More problems have arisen in unanchored patterns when CRLF is a valid line
995        break. For example, the unstudied pattern [\r\n]A does not match the string
996        "\r\nA" because change 7.0/46 below moves the current point on by two
997        characters after failing to match at the start. However, the pattern \nA
998        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
999        the same is true. There doesn't seem any very clean way out of this, but
1000        what I have chosen to do makes the common cases work: PCRE now takes note
1001        of whether there can be an explicit match for \r or \n anywhere in the
1002        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1003        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1004        pattern has explicit CR or LF references.
1006    29. Added (*CR) etc for changing newline setting at start of pattern.
1009    Version 7.2 19-Jun-07
1010    ---------------------
1012     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1013        which is apparently normally available under Windows.
1015     2. Re-jig the pcregrep tests with different newline settings in an attempt
1016        to make them independent of the local environment's newline setting.
1018     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1020     4. Some of the "internals" tests were previously cut out when the link size
1021        was not 2, because the output contained actual offsets. The recent new
1022        "Z" feature of pcretest means that these can be cut out, making the tests
1023        usable with all link sizes.
1025     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1026        stack recursion. This gives a massive performance boost under BSD, but just
1027        a small improvement under Linux. However, it saves one field in the frame
1028        in all cases.
1030     6. Added more features from the forthcoming Perl 5.10:
1032        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1033            recursion call. It refers to the nth most recently opened parentheses.
1035        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1036            to be opened parentheses.
1038        (c) Conditions that refer to capturing parentheses can be specified
1039            relatively, for example, (?(-2)... or (?(+3)...
1041        (d) \K resets the start of the current match so that everything before
1042            is not part of it.
1044        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1046        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1047            reference syntax.
1049        (g) (?| introduces a group in which the numbering of parentheses in each
1050            alternative starts with the same number.
1052        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1054     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1057     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1058        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1059        for detecting groups that can match an empty string.
1061     9. A pattern with a very large number of alternatives (more than several
1062        hundred) was running out of internal workspace during the pre-compile
1063        phase, where pcre_compile() figures out how much memory will be needed. A
1064        bit of new cunning has reduced the workspace needed for groups with
1065        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1066        workspace instead of running out of the 4096 that are available.
1068    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1070    11. Applied patch from Google to remove an optimization that didn't quite work.
1071        The report of the bug said:
1073          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1074          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1075          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1077    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1078        it matched the wrong number of bytes.
1081    Version 7.1 24-Apr-07
1082    ---------------------
1084     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1085        that is more "standard", making use of automake and other Autotools. There
1086        is some re-arrangement of the files and adjustment of comments consequent
1087        on this.
1089     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1090        for recursive directory scanning broke on some systems because the files
1091        are not scanned in any specific order and on different systems the order
1092        was different. A call to "sort" has been inserted into RunGrepTest for the
1093        approprate test as a short-term fix. In the longer term there may be an
1094        alternative.
1096     3. I had an email from Eric Raymond about problems translating some of PCRE's
1097        man pages to HTML (despite the fact that I distribute HTML pages, some
1098        people do their own conversions for various reasons). The problems
1099        concerned the use of low-level troff macros .br and .in. I have therefore
1100        removed all such uses from the man pages (some were redundant, some could
1101        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1102        HTML has been updated to handle .nf/.fi and to complain if it encounters
1103        .br or .in.
1105     4. Updated comments in configure.ac that get placed in config.h.in and also
1106        arranged for config.h to be included in the distribution, with the name
1107        config.h.generic, for the benefit of those who have to compile without
1108        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1110     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1111        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1112        makevp.bat for the current PCRE, using the additional files
1113        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1115     6. A Windows user reported a minor discrepancy with test 2, which turned out
1116        to be caused by a trailing space on an input line that had got lost in his
1117        copy. The trailing space was an accident, so I've just removed it.
1119     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1120        that is needed.
1122     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1123        as "const" (a) because they are and (b) because it helps the PHP
1124        maintainers who have recently made a script to detect big data structures
1125        in the php code that should be moved to the .rodata section. I remembered
1126        to update Builducptable as well, so it won't revert if ucptable.h is ever
1127        re-created.
1129     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1130        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1131        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1132        support is not required. This saves 1.5-2K of code, which is important in
1133        some applications.
1135        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1136        so as not to refer to the tables, even though these functions will never be
1137        called when UTF-8 support is disabled. Otherwise there are problems with a
1138        shared library.
1140    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1142        (a) It was defining its arguments as char * instead of void *.
1144        (b) It was assuming that all moves were upwards in memory; this was true
1145            a long time ago when I wrote it, but is no longer the case.
1147        The emulated memove() is provided for those environments that have neither
1148        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1149        is clearly not the case, as these two bugs were recently reported.
1151    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1152        and Detrail to create the HTML documentation, the .txt form of the man
1153        pages, and it removes trailing spaces from listed files. It also creates
1154        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1155        case, it wraps all the #defines with #ifndefs. This script should be run
1156        before "make dist".
1158    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1159        with Unicode property support.
1161        (a) For a maximizing quantifier, if the two different cases of the
1162            character were of different lengths in their UTF-8 codings (there are
1163            some cases like this - I found 11), and the matching function had to
1164            back up over a mixture of the two cases, it incorrectly assumed they
1165            were both the same length.
1167        (b) When PCRE was configured to use the heap rather than the stack for
1168            recursion during matching, it was not correctly preserving the data for
1169            the other case of a UTF-8 character when checking ahead for a match
1170            while processing a minimizing repeat. If the check also involved
1171            matching a wide character, but failed, corruption could cause an
1172            erroneous result when trying to check for a repeat of the original
1173            character.
1175    13. Some tidying changes to the testing mechanism:
1177        (a) The RunTest script now detects the internal link size and whether there
1178            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1179            values substituted by "configure". (The RunGrepTest script already did
1180            this for UTF-8.) The configure.ac script no longer substitutes the
1181            relevant variables.
1183        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1184            with length and offset values. This means that the output is different
1185            for different internal link sizes. Test 2 is skipped for link sizes
1186            other than 2 because of this, bypassing the problem. Unfortunately,
1187            there was also a test in test 3 (the locale tests) that used /B and
1188            failed for link sizes other than 2. Rather than cut the whole test out,
1189            I have added a new /Z option to pcretest that replaces the length and
1190            offset values with spaces. This is now used to make test 3 independent
1191            of link size. (Test 2 will be tidied up later.)
1193    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1194        segmentation fault instead of returning the appropriate error message.
1196    15. In multiline mode when the newline sequence was set to "any", the pattern
1197        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1198        This doesn't seem right; it now treats the CRLF combination as the line
1199        ending, and so does not match in that case. It's only a pattern such as ^$
1200        that would hit this one: something like ^ABC$ would have failed after \r
1201        and then tried again after \r\n.
1203    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1204        in an attempt to make files that differ only in their line terminators
1205        compare equal. This works on Linux.
1207    17. Under certain error circumstances pcregrep might try to free random memory
1208        as it exited. This is now fixed, thanks to valgrind.
1210    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1211        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1212        was because its rules for how to advance for /g after matching an empty
1213        string at the end of a line did not allow for this case. They now check for
1214        it specially.
1216    20. pcretest is supposed to handle patterns and data of any length, by
1217        extending its buffers when necessary. It was getting this wrong when the
1218        buffer for a data line had to be extended.
1220    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1221        CRLF as a newline sequence.
1223    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1224        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1225        I have nevertheless tidied it up.
1227    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1229    24. Added a man page for pcre-config.
1232    Version 7.0 19-Dec-06
1233    ---------------------
1235     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1236        moving to gcc 4.1.1.
1238     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1239        sys/time.h, which is documented as needed for this function. It doesn't
1240        seem to matter on Linux, but it showed up on some releases of OS X.
1242     3. It seems that there are systems where bytes whose values are greater than
1243        127 match isprint() in the "C" locale. The "C" locale should be the
1244        default when a C program starts up. In most systems, only ASCII printing
1245        characters match isprint(). This difference caused the output from pcretest
1246        to vary, making some of the tests fail. I have changed pcretest so that:
1248        (a) When it is outputting text in the compiled version of a pattern, bytes
1249            other than 32-126 are always shown as hex escapes.
1251        (b) When it is outputting text that is a matched part of a subject string,
1252            it does the same, unless a different locale has been set for the match
1253            (using the /L modifier). In this case, it uses isprint() to decide.
1255     4. Fixed a major bug that caused incorrect computation of the amount of memory
1256        required for a compiled pattern when options that changed within the
1257        pattern affected the logic of the preliminary scan that determines the
1258        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1259        that the computed length was too small. The symptoms of this bug were
1260        either the PCRE error "internal error: code overflow" from pcre_compile(),
1261        or a glibc crash with a message such as "pcretest: free(): invalid next
1262        size (fast)". Examples of patterns that provoked this bug (shown in
1263        pcretest format) are:
1265          /(?-x: )/x
1266          /(?x)(?-x: \s*#\s*)/
1267          /((?i)[\x{c0}])/8
1268          /(?i:[\x{c0}])/8
1270        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1271        is now done differently.
1273     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1274        wrapper classes; (b) implement a new function in the C++ scanner that is
1275        more efficient than the old way of doing things because it avoids levels of
1276        recursion in the regex matching; (c) add a paragraph to the documentation
1277        for the FullMatch() function.
1279     6. The escape sequence \n was being treated as whatever was defined as
1280        "newline". Not only was this contrary to the documentation, which states
1281        that \n is character 10 (hex 0A), but it also went horribly wrong when
1282        "newline" was defined as CRLF. This has been fixed.
1284     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1285        was being set to -1 for the "end of line" case (supposedly a value that no
1286        character can have). Though this value is never used (the check for end of
1287        line is "zero bytes in current character"), it caused compiler complaints.
1288        I've changed it to 0xffffffff.
1290     8. In pcre_version.c, the version string was being built by a sequence of
1291        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1292        string (as it is for production releases) called a macro with an empty
1293        argument. The C standard says the result of this is undefined. The gcc
1294        compiler treats it as an empty string (which was what was wanted) but it is
1295        reported that Visual C gives an error. The source has been hacked around to
1296        avoid this problem.
1298     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1299        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1300        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1301        of them did).
1303    10. Originally, pcretest opened its input and output without "b"; then I was
1304        told that "b" was needed in some environments, so it was added for release
1305        5.0 to both the input and output. (It makes no difference on Unix-like
1306        systems.) Later I was told that it is wrong for the input on Windows. I've
1307        now abstracted the modes into two macros, to make it easier to fiddle with
1308        them, and removed "b" from the input mode under Windows.
1310    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1312    12. Added -help and --help to pcretest as an official way of being reminded
1313        of the options.
1315    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1316        and pcrecpp.cc because they annoy compilers at high warning levels.
1318    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1320    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1321        scripts are not C programs :-) and which was not noticed because it works
1322        on Linux.
1324    16. pcretest is supposed to handle any length of pattern and data line (as one
1325        line or as a continued sequence of lines) by extending its input buffer if
1326        necessary. This feature was broken for very long pattern lines, leading to
1327        a string of junk being passed to pcre_compile() if the pattern was longer
1328        than about 50K.
1330    17. I have done a major re-factoring of the way pcre_compile() computes the
1331        amount of memory needed for a compiled pattern. Previously, there was code
1332        that made a preliminary scan of the pattern in order to do this. That was
1333        OK when PCRE was new, but as the facilities have expanded, it has become
1334        harder and harder to keep it in step with the real compile phase, and there
1335        have been a number of bugs (see for example, 4 above). I have now found a
1336        cunning way of running the real compile function in a "fake" mode that
1337        enables it to compute how much memory it would need, while actually only
1338        ever using a few hundred bytes of working memory and without too many
1339        tests of the mode. This should make future maintenance and development
1340        easier. A side effect of this work is that the limit of 200 on the nesting
1341        depth of parentheses has been removed (though this was never a serious
1342        limitation, I suspect). However, there is a downside: pcre_compile() now
1343        runs more slowly than before (30% or more, depending on the pattern). I
1344        hope this isn't a big issue. There is no effect on runtime performance.
1346    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1347        newline (only possible for the last line of a file) and it was a
1348        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1350    19. Added additional timing features to pcretest. (1) The -tm option now times
1351        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1352        separate command line item, by a number that specifies the number of
1353        repeats to use when timing. The default is 50000; this gives better
1354        precision, but takes uncomfortably long for very large patterns.
1356    20. Extended pcre_study() to be more clever in cases where a branch of a
1357        subpattern has no definite first character. For example, (a*|b*)[cd] would
1358        previously give no result from pcre_study(). Now it recognizes that the
1359        first character must be a, b, c, or d.
1361    21. There was an incorrect error "recursive call could loop indefinitely" if
1362        a subpattern (or the entire pattern) that was being tested for matching an
1363        empty string contained only one non-empty item after a nested subpattern.
1364        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1365        incorrectly, because the \d was being skipped in the check.
1367    22. The pcretest program now has a new pattern option /B and a command line
1368        option -b, which is equivalent to adding /B to every pattern. This causes
1369        it to show the compiled bytecode, without the additional information that
1370        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1371        is the same as /B/I).
1373    23. A new optimization is now able automatically to treat some sequences such
1374        as a*b as a*+b. More specifically, if something simple (such as a character
1375        or a simple class like \d) has an unlimited quantifier, and is followed by
1376        something that cannot possibly match the quantified thing, the quantifier
1377        is automatically "possessified".
1379    24. A recursive reference to a subpattern whose number was greater than 39
1380        went wrong under certain circumstances in UTF-8 mode. This bug could also
1381        have affected the operation of pcre_study().
1383    25. Realized that a little bit of performance could be had by replacing
1384        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1386    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1388    27. Possessive quantifiers such as a++ were previously implemented by turning
1389        them into atomic groups such as ($>a+). Now they have their own opcodes,
1390        which improves performance. This includes the automatically created ones
1391        from 23 above.
1393    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1394        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1395        the first matched character to be a colon. This applied both to named and
1396        numbered groups.
1398    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1400    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1401        building PCRE on Windows easier, so I have included it in the distribution.
1403    31. There is now a check in pcretest against a ridiculously large number being
1404        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1405        loop, the loop is abandoned.
1407    32. Forward references to subpatterns in conditions such as (?(2)...) where
1408        subpattern 2 is defined later cause pcre_compile() to search forwards in
1409        the pattern for the relevant set of parentheses. This search went wrong
1410        when there were unescaped parentheses in a character class, parentheses
1411        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1413    33. "Subroutine" calls and backreferences were previously restricted to
1414        referencing subpatterns earlier in the regex. This restriction has now
1415        been removed.
1417    34. Added a number of extra features that are going to be in Perl 5.10. On the
1418        whole, these are just syntactic alternatives for features that PCRE had
1419        previously implemented using the Python syntax or my own invention. The
1420        other formats are all retained for compatibility.
1422        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1423            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1424            also .NET compatible.
1426        (b) A recursion or subroutine call to a named group can now be defined as
1427            (?&name) as well as (?P>name).
1429        (c) A backreference to a named group can now be defined as \k<name> or
1430            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1431            5.10, are also .NET compatible.
1433        (d) A conditional reference to a named group can now use the syntax
1434            (?(<name>) or (?('name') as well as (?(name).
1436        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1437            groups (named and numbered) that are never evaluated inline, but can be
1438            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1439            is always false. There may be only one alternative in such a group.
1441        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1442            as the simple (?(R). The condition is true only if the most recent
1443            recursion is that of the given number or name. It does not search out
1444            through the entire recursion stack.
1446        (g) The escape \gN or \g{N} has been added, where N is a positive or
1447            negative number, specifying an absolute or relative reference.
1449    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1450        some "unreachable code" warnings.
1452    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1453        things, this adds five new scripts.
1455    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1456        There were also incompatibilities regarding the handling of \Q..\E inside
1457        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1458        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1460    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1461        matches an empty string, and forcibly breaks the loop. There were bugs in
1462        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1463        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1464        separate and independent bugs (that affected different cases) have been
1465        fixed.
1467    39. Refactored the code to abolish the use of different opcodes for small
1468        capturing bracket numbers. This is a tidy that I avoided doing when I
1469        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1470        The new approach is not only tidier, it makes it possible to reduce the
1471        memory needed to fix the previous bug (38).
1473    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1474        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1475        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1476        mode.
1478    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1479        report.
1481    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1482        copy construction and assignment in the C++ wrapper.
1484    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1485        couple of bugs that could have given wrong results in the "--newline=crlf"
1486        case.
1488    44. Added a number of casts and did some reorganization of signed/unsigned int
1489        variables following suggestions from Dair Grant. Also renamed the variable
1490        "this" as "item" because it is a C++ keyword.
1492    45. Arranged for dftables to add
1494          #include "pcre_internal.h"
1496        to pcre_chartables.c because without it, gcc 4.x may remove the array
1497        definition from the final binary if PCRE is built into a static library and
1498        dead code stripping is activated.
1500    46. For an unanchored pattern, if a match attempt fails at the start of a
1501        newline sequence, and the newline setting is CRLF or ANY, and the next two
1502        characters are CRLF, advance by two characters instead of one.
1505  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
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