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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.02 01-Mar-2010
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 5.2.0.
9    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
10        configured.
12    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
13        original author of that file, following a query about its status.
15    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
16        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
18    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
19        quantifier applied to a forward-referencing subroutine call, could compile
20        incorrect code or give the error "internal error: previously-checked
21        referenced subpattern not found".
24    Version 8.01 19-Jan-2010
25    ------------------------
27    1.  If a pattern contained a conditional subpattern with only one branch (in
28        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
29        computed the wrong minimum data length (which is of course zero for such
30        subpatterns). This could cause incorrect "no match" results.
32    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
33        the pattern is reset in the first branch, pcre_compile() failed with
34        "internal error: code overflow at offset...". This happened only when
35        the reset was to the original external option setting. (An optimization
36        abstracts leading options settings into an external setting, which was the
37        cause of this.)
39    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
40        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
41        assertion pattern did not match (meaning that the assertion was true), it
42        was incorrectly treated as false if the SKIP had been reached during the
43        matching. This also applied to assertions used as conditions.
45    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
46        assertion subpattern, including such a pattern used as a condition,
47        unpredictable results occurred, instead of the error return
50    5.  The C++ GlobalReplace function was not working like Perl for the special
51        situation when an empty string is matched. It now does the fancy magic
52        stuff that is necessary.
54    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
55        removed. (These were left over from very, very early versions of PCRE.)
57    7.  Some cosmetic changes to the code to make life easier when compiling it
58        as part of something else:
60        (a) Change DEBUG to PCRE_DEBUG.
62        (b) In pcre_compile(), rename the member of the "branch_chain" structure
63            called "current" as "current_branch", to prevent a collision with the
64            Linux macro when compiled as a kernel module.
66        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
67            prevent a collision with the Linux macro when compiled as a kernel
68            module.
70    8.  In pcre_compile() there are some checks for integer overflows that used to
71        cast potentially large values to (double). This has been changed to that
72        when building, a check for int64_t is made, and if it is found, it is used
73        instead, thus avoiding the use of floating point arithmetic. (There is no
74        other use of FP in PCRE.) If int64_t is not found, the fallback is to
75        double.
77    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
78        2005 (difference between two addresses compared to an unsigned value).
80    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
81        custom one, because of the following reported problem in Windows:
83          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
84              under Win32.
85          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
86              therefore missing the function definition.
87          - The compiler thus generates a "C" signature for the test function.
88          - The linker fails to find the "C" function.
89          - PCRE fails to configure if asked to do so against libbz2.
91    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
92        messages were output:
94          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
95          rerunning libtoolize, to keep the correct libtool macros in-tree.
96          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
98        I have done both of these things.
100    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
101        most of the time, it *can* run out if it is given a pattern that contains a
102        runaway infinite recursion. I updated the discussion in the pcrestack man
103        page.
105    13. Now that we have gone to the x.xx style of version numbers, the minor
106        version may start with zero. Using 08 or 09 is a bad idea because users
107        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
108        interpreted as invalid octal numbers. I've updated the previous comment in
109        configure.ac, and also added a check that gives an error if 08 or 09 are
110        used.
112    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
113        causing partial matching to fail when the end of the subject matched \W
114        in a UTF-8 pattern where \W was quantified with a minimum of 3.
116    15. There were some discrepancies between the declarations in pcre_internal.h
117        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
118        their definitions. The declarations used "const uschar *" and the
119        definitions used USPTR. Even though USPTR is normally defined as "const
120        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
121        reported that: "This difference in casting confuses some C++ compilers, for
122        example, SunCC recognizes above declarations as different functions and
123        generates broken code for hbpcre." I have changed the declarations to use
124        USPTR.
126    16. GNU libtool is named differently on some systems. The autogen.sh script now
127        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
128        (FreeBSD).
130    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
131        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
132        comment: "Figure out how to create a longlong from a string: strtoll and
133        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
134        instance, but it only takes 2 args instead of 3!"
136    18. A subtle bug concerned with back references has been fixed by a change of
137        specification, with a corresponding code fix. A pattern such as
138        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
139        refers, was giving matches when it shouldn't. For example, xa=xaaa would
140        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
141        same bug. Such groups have to be quantified to be useful, or contained
142        inside another quantified group. (If there's no repetition, the reference
143        can never match.) The problem arises because, having left the group and
144        moved on to the rest of the pattern, a later failure that backtracks into
145        the group uses the captured value from the final iteration of the group
146        rather than the correct earlier one. I have fixed this in PCRE by forcing
147        any group that contains a reference to itself to be an atomic group; that
148        is, there cannot be any backtracking into it once it has completed. This is
149        similar to recursive and subroutine calls.
152    Version 8.00 19-Oct-09
153    ----------------------
155    1.  The table for translating pcre_compile() error codes into POSIX error codes
156        was out-of-date, and there was no check on the pcre_compile() error code
157        being within the table. This could lead to an OK return being given in
158        error.
160    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
161        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
162        in a Windows environment.
164    3.  The pcregrep --count option prints the count for each file even when it is
165        zero, as does GNU grep. However, pcregrep was also printing all files when
166        --files-with-matches was added. Now, when both options are given, it prints
167        counts only for those files that have at least one match. (GNU grep just
168        prints the file name in this circumstance, but including the count seems
169        more useful - otherwise, why use --count?) Also ensured that the
170        combination -clh just lists non-zero counts, with no names.
172    4.  The long form of the pcregrep -F option was incorrectly implemented as
173        --fixed_strings instead of --fixed-strings. This is an incompatible change,
174        but it seems right to fix it, and I didn't think it was worth preserving
175        the old behaviour.
177    5.  The command line items --regex=pattern and --regexp=pattern were not
178        recognized by pcregrep, which required --regex pattern or --regexp pattern
179        (with a space rather than an '='). The man page documented the '=' forms,
180        which are compatible with GNU grep; these now work.
182    6.  No libpcreposix.pc file was created for pkg-config; there was just
183        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
185    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
186        when UCP support is not needed, by modifying the Python script that
187        generates it from Unicode data files. This should not matter if the module
188        is correctly used as a library, but I received one complaint about 50K of
189        unwanted data. My guess is that the person linked everything into his
190        program rather than using a library. Anyway, it does no harm.
192    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
193        was a minimum greater than 1 for a wide character in a possessive
194        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
195        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
196        character. Chaos in the form of incorrect output or a compiling loop could
197        result.
199    9.  The restrictions on what a pattern can contain when partial matching is
200        requested for pcre_exec() have been removed. All patterns can now be
201        partially matched by this function. In addition, if there are at least two
202        slots in the offset vector, the offset of the earliest inspected character
203        for the match and the offset of the end of the subject are set in them when
204        PCRE_ERROR_PARTIAL is returned.
206    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
207        synonymous with PCRE_PARTIAL, for backwards compatibility, and
208        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
209        and may be more useful for multi-segment matching.
211    11. Partial matching with pcre_exec() is now more intuitive. A partial match
212        used to be given if ever the end of the subject was reached; now it is
213        given only if matching could not proceed because another character was
214        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
215        string "Z", which now yields "no match" instead of "partial match". In the
216        case of pcre_dfa_exec(), "no match" is given if every matching path for the
217        final character ended with (*FAIL).
219    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
220        if the pattern had a "must contain" character that was already found in the
221        earlier partial match, unless partial matching was again requested. For
222        example, with the pattern /dog.(body)?/, the "must contain" character is
223        "g". If the first part-match was for the string "dog", restarting with
224        "sbody" failed. This bug has been fixed.
226    13. The string returned by pcre_dfa_exec() after a partial match has been
227        changed so that it starts at the first inspected character rather than the
228        first character of the match. This makes a difference only if the pattern
229        starts with a lookbehind assertion or \b or \B (\K is not supported by
230        pcre_dfa_exec()). It's an incompatible change, but it makes the two
231        matching functions compatible, and I think it's the right thing to do.
233    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
234        so that the demonstration program is easily available in environments where
235        PCRE has not been installed from source.
237    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
238        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
239        library.
241    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
242        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
243        is not the first non-POSIX option to be added. Clearly some people find
244        these options useful.
246    17. If a caller to the POSIX matching function regexec() passes a non-zero
247        value for nmatch with a NULL value for pmatch, the value of
248        nmatch is forced to zero.
250    18. RunGrepTest did not have a test for the availability of the -u option of
251        the diff command, as RunTest does. It now checks in the same way as
252        RunTest, and also checks for the -b option.
254    19. If an odd number of negated classes containing just a single character
255        interposed, within parentheses, between a forward reference to a named
256        subpattern and the definition of the subpattern, compilation crashed with
257        an internal error, complaining that it could not find the referenced
258        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
259        [The bug was that it was starting one character too far in when skipping
260        over the character class, thus treating the ] as data rather than
261        terminating the class. This meant it could skip too much.]
263    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
264        /g option in pcretest when the pattern contains \K, which makes it possible
265        to have an empty string match not at the start, even when the pattern is
266        anchored. Updated pcretest and pcredemo to use this option.
268    21. If the maximum number of capturing subpatterns in a recursion was greater
269        than the maximum at the outer level, the higher number was returned, but
270        with unset values at the outer level. The correct (outer level) value is
271        now given.
273    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
274        PCRE did not set those parentheses (unlike Perl). I have now found a way to
275        make it do so. The string so far is captured, making this feature
276        compatible with Perl.
278    23. The tests have been re-organized, adding tests 11 and 12, to make it
279        possible to check the Perl 5.10 features against Perl 5.10.
281    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
282        pattern matches a fixed length string. PCRE did not allow this; now it
283        does. Neither allows recursion.
285    25. I finally figured out how to implement a request to provide the minimum
286        length of subject string that was needed in order to match a given pattern.
287        (It was back references and recursion that I had previously got hung up
288        on.) This code has now been added to pcre_study(); it finds a lower bound
289        to the length of subject needed. It is not necessarily the greatest lower
290        bound, but using it to avoid searching strings that are too short does give
291        some useful speed-ups. The value is available to calling programs via
292        pcre_fullinfo().
294    26. While implementing 25, I discovered to my embarrassment that pcretest had
295        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
296        study optimizations had never been tested with that matching function.
297        Oops. What is worse, even when it was passed study data, there was a bug in
298        pcre_dfa_exec() that meant it never actually used it. Double oops. There
299        were also very few tests of studied patterns with pcre_dfa_exec().
301    27. If (?| is used to create subpatterns with duplicate numbers, they are now
302        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
303        on the other side of the coin, they are no longer allowed to have different
304        names, because these cannot be distinguished in PCRE, and this has caused
305        confusion. (This is a difference from Perl.)
307    28. When duplicate subpattern names are present (necessarily with different
308        numbers, as required by 27 above), and a test is made by name in a
309        conditional pattern, either for a subpattern having been matched, or for
310        recursion in such a pattern, all the associated numbered subpatterns are
311        tested, and the overall condition is true if the condition is true for any
312        one of them. This is the way Perl works, and is also more like the way
313        testing by number works.
316    Version 7.9 11-Apr-09
317    ---------------------
319    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
320        (pcretest), all targets were linked against these libraries. This included
321        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
322        libraries. This caused unwanted dependencies to be created. This problem
323        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
324        pcretest is linked with readline.
326    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
327        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
328        moved outside it again, because FALSE and TRUE are already defined in AIX,
329        but BOOL is not.
331    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
332        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
334    4.  The pcregrep documentation said spaces were inserted as well as colons (or
335        hyphens) following file names and line numbers when outputting matching
336        lines. This is not true; no spaces are inserted. I have also clarified the
337        wording for the --colour (or --color) option.
339    5.  In pcregrep, when --colour was used with -o, the list of matching strings
340        was not coloured; this is different to GNU grep, so I have changed it to be
341        the same.
343    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
344        each matching line was coloured. Now it goes on to look for further matches
345        of any of the test patterns, which is the same behaviour as GNU grep.
347    7.  A pattern that could match an empty string could cause pcregrep to loop; it
348        doesn't make sense to accept an empty string match in pcregrep, so I have
349        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
350        seems to be how GNU grep behaves.
352    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
353        start or after a newline", because the conditional assertion was not being
354        correctly handled. The rule now is that both the assertion and what follows
355        in the first alternative must satisfy the test.
357    9.  If auto-callout was enabled in a pattern with a conditional group whose
358        condition was an assertion, PCRE could crash during matching, both with
359        pcre_exec() and pcre_dfa_exec().
361    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
362        used for matching.
364    11. Unicode property support in character classes was not working for
365        characters (bytes) greater than 127 when not in UTF-8 mode.
367    12. Added the -M command line option to pcretest.
369    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
371    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
373    16. Added comments and documentation about mis-use of no_arg in the C++
374        wrapper.
376    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
377        from Martin Jerabek that uses macro names for all relevant character and
378        string constants.
380    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
381        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
382        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
383        these, but not everybody uses configure.
385    19. A conditional group that had only one branch was not being correctly
386        recognized as an item that could match an empty string. This meant that an
387        enclosing group might also not be so recognized, causing infinite looping
388        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
389        with the subject "ab", where knowledge that the repeated group can match
390        nothing is needed in order to break the loop.
392    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
393        exec(), but without supplying a callout function, matching went wrong.
395    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
396        leak if the size of the offset vector was greater than 30. When the vector
397        is smaller, the saved offsets during recursion go onto a local stack
398        vector, but for larger vectors malloc() is used. It was failing to free
399        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
400        error, in fact).
402    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
403        heapframe that is used only when UTF-8 support is enabled. This caused no
404        problem, but was untidy.
406    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
407        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
408        included within another project.
410    24. Steven Van Ingelgem's patches to add more options to the CMake support,
411        slightly modified by me:
413          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
414              not building pcregrep.
416          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
417              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
419    25. Forward references, both numeric and by name, in patterns that made use of
420        duplicate group numbers, could behave incorrectly or give incorrect errors,
421        because when scanning forward to find the reference group, PCRE was not
422        taking into account the duplicate group numbers. A pattern such as
423        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
425    26. Changed a few more instances of "const unsigned char *" to USPTR, making
426        the feature of a custom pointer more persuasive (as requested by a user).
428    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
429        pcretest.c, inside #ifndefs, because it seems they are sometimes already
430        pre-defined.
432    28. Added support for (*UTF8) at the start of a pattern.
434    29. Arrange for flags added by the "release type" setting in CMake to be shown
435        in the configuration summary.
438    Version 7.8 05-Sep-08
439    ---------------------
441    1.  Replaced UCP searching code with optimized version as implemented for Ad
442        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
443        stage table and inline lookup instead of a function, giving speed ups of 2
444        to 5 times on some simple patterns that I tested. Permission was given to
445        distribute the MultiStage2.py script that generates the tables (it's not in
446        the tarball, but is in the Subversion repository).
448    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
449        scripts.
451    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
452        a group with a zero qualifier. The result of the study could be incorrect,
453        or the function might crash, depending on the pattern.
455    4.  Caseless matching was not working for non-ASCII characters in back
456        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
457        It now works when Unicode Property Support is available.
459    5.  In pcretest, an escape such as \x{de} in the data was always generating
460        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
461        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
462        truncation.
464    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
466    7.  Added two (int) casts to pcregrep when printing the difference of two
467        pointers, in case they are 64-bit values.
469    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
470        test 2 if it fails.
472    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
473        and a #define of that name to empty if it is not externally set. This is to
474        allow users of MSVC to set it if necessary.
476    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
477        the convenience functions in the pcre_get.c source file.
479    11. An option change at the start of a pattern that had top-level alternatives
480        could cause overwriting and/or a crash. This command provoked a crash in
481        some environments:
483          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
485        This potential security problem was recorded as CVE-2008-2371.
487    12. For a pattern where the match had to start at the beginning or immediately
488        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
489        pcre_dfa_exec() could read past the end of the passed subject if there was
490        no match. To help with detecting such bugs (e.g. with valgrind), I modified
491        pcretest so that it places the subject at the end of its malloc-ed buffer.
493    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
494        exec() might read past the end of the data buffer in UTF-8 mode.
496    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
497        the data contained the byte 0x85 as part of a UTF-8 character within its
498        first line. This applied both to normal and DFA matching.
500    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
501        /^[^d]*?$/8 failed to match "abc".
503    16. Added a missing copyright notice to pcrecpp_internal.h.
505    17. Make it more clear in the documentation that values returned from
506        pcre_exec() in ovector are byte offsets, not character counts.
508    18. Tidied a few places to stop certain compilers from issuing warnings.
510    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
511        supplied by Stefan Weber. I made a further small update for 7.8 because
512        there is a change of source arrangements: the pcre_searchfuncs.c module is
513        replaced by pcre_ucd.c.
516    Version 7.7 07-May-08
517    ---------------------
519    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
520        a string to a long long, pretend we don't even have a long long." This is
521        done by checking for the strtoq, strtoll, and _strtoi64 functions.
523    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
524        pre-7.6 versions, which defined a global no_arg variable instead of putting
525        it in the RE class. (See also #8 below.)
527    3.  Remove a line of dead code, identified by coverity and reported by Nuno
528        Lopes.
530    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
532        (1) The include/exclude patterns were being applied to the whole pathnames
533            of files, instead of just to the final components.
535        (2) If there was more than one level of directory, the subdirectories were
536            skipped unless they satisfied the include/exclude conditions. This is
537            inconsistent with GNU grep (and could even be seen as contrary to the
538            pcregrep specification - which I improved to make it absolutely clear).
539            The action now is always to scan all levels of directory, and just
540            apply the include/exclude patterns to regular files.
542    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
543        --exclude_dir in the tests to avoid scanning .svn directories.
545    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
546        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
547        doesn't support NULs in patterns.
549    7.  Added some missing "const"s to declarations of static tables in
550        pcre_compile.c and pcre_dfa_exec.c.
552    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
553        caused by fix #2  above. (Subsequently also a second patch to fix the
554        first patch. And a third patch - this was a messy problem.)
556    9.  Applied Craig's patch to remove the use of push_back().
558    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
559        matching function regexec().
561    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
562        which, however, unlike Perl's \g{...}, are subroutine calls, not back
563        references. PCRE supports relative numbers with this syntax (I don't think
564        Oniguruma does).
566    12. Previously, a group with a zero repeat such as (...){0} was completely
567        omitted from the compiled regex. However, this means that if the group
568        was called as a subroutine from elsewhere in the pattern, things went wrong
569        (an internal error was given). Such groups are now left in the compiled
570        pattern, with a new opcode that causes them to be skipped at execution
571        time.
573    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
574        to the way PCRE behaves:
576        (a) A lone ] character is dis-allowed (Perl treats it as data).
578        (b) A back reference to an unmatched subpattern matches an empty string
579            (Perl fails the current match path).
581        (c) A data ] in a character class must be notated as \] because if the
582            first data character in a class is ], it defines an empty class. (In
583            Perl it is not possible to have an empty class.) The empty class []
584            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
585            The negative empty class [^] matches any one character, independently
586            of the DOTALL setting.
588    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
589        non-existent subpattern following a character class starting with ']' and
590        containing () gave an internal compiling error instead of "reference to
591        non-existent subpattern". Fortunately, when the pattern did exist, the
592        compiled code was correct. (When scanning forwards to check for the
593        existencd of the subpattern, it was treating the data ']' as terminating
594        the class, so got the count wrong. When actually compiling, the reference
595        was subsequently set up correctly.)
597    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
598        it was being rejected as not supported by pcre_dfa_exec(), even though
599        other assertions are supported. I have made pcre_dfa_exec() support
600        (*FAIL).
602    16. The implementation of 13c above involved the invention of a new opcode,
603        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
604        cannot be changed at match time, I realized I could make a small
605        improvement to matching performance by compiling OP_ALLANY instead of
606        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
607        on the OP_ANY path.
609    17. Compiling pcretest on Windows with readline support failed without the
610        following two fixes: (1) Make the unistd.h include conditional on
611        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
613    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
614        ncurses library to be included for pcretest when ReadLine support is
615        requested, but also to allow for it to be overridden. This patch came from
616        Daniel Bergström.
618    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
619        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
620        any errors with the current Unicode tables. Thanks to Peter Kankowski for
621        spotting this.
624    Version 7.6 28-Jan-08
625    ---------------------
627    1.  A character class containing a very large number of characters with
628        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
629        overflow.
631    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
632        HAVE_LONG_LONG is not defined.
634    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
635        bring them up to date and include new features. This patch includes:
637        - Fixed PH's badly added libz and libbz2 support.
638        - Fixed a problem with static linking.
639        - Added pcredemo. [But later removed - see 7 below.]
640        - Fixed dftables problem and added an option.
641        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
642            HAVE_LONG_LONG.
643        - Added readline support for pcretest.
644        - Added an listing of the option settings after cmake has run.
646    4.  A user submitted a patch to Makefile that makes it easy to create
647        "pcre.dll" under mingw when using Configure/Make. I added stuff to
648        Makefile.am that cause it to include this special target, without
649        affecting anything else. Note that the same mingw target plus all
650        the other distribution libraries and programs are now supported
651        when configuring with CMake (see 6 below) instead of with
652        Configure/Make.
654    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
655        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
656        exported in the Windows port". It has not yet been confirmed that the patch
657        solves the problem, but it does no harm.
659    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
660        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
661        with CMake, and also correct the comment about stack recursion.
663    7.  Remove the automatic building of pcredemo from the ./configure system and
664        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
665        of a program that users should build themselves after PCRE is installed, so
666        building it automatically is not really right. What is more, it gave
667        trouble in some build environments.
669    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
672    Version 7.5 10-Jan-08
673    ---------------------
675    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
676        values in parens when parsing an RE using the C++ wrapper."
678    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
679        Characters greater than 255 were excluded from the class instead of being
680        included.
682    3.  The same bug as (2) above applied to negated POSIX classes such as
683        [:^space:].
685    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
686        defined or documented. It seems to have been a typo for PCRE_STATIC, so
687        I have changed it.
689    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
690        first named subpattern) and a construct such as (?&a) would reference the
691        first named subpattern whose name started with "a" (in other words, the
692        length check was missing). Both these problems are fixed. "Subpattern name
693        expected" is now given for (?&) (a zero-length name), and this patch also
694        makes it give the same error for \k'' (previously it complained that that
695        was a reference to a non-existent subpattern).
697    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
698        this is right because (?- can be followed by option settings as well as by
699        digits. I have, however, made the messages clearer.
701    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
702        than the number used in the conditional) now cause a compile-time error.
703        This is actually not compatible with Perl, which accepts such patterns, but
704        treats the conditional as always being FALSE (as PCRE used to), but it
705        seems to me that giving a diagnostic is better.
707    8.  Change "alphameric" to the more common word "alphanumeric" in comments
708        and messages.
710    9.  Fix two occurrences of "backslash" in comments that should have been
711        "backspace".
713    10. Remove two redundant lines of code that can never be obeyed (their function
714        was moved elsewhere).
716    11. The program that makes PCRE's Unicode character property table had a bug
717        which caused it to generate incorrect table entries for sequences of
718        characters that have the same character type, but are in different scripts.
719        It amalgamated them into a single range, with the script of the first of
720        them. In other words, some characters were in the wrong script. There were
721        thirteen such cases, affecting characters in the following ranges:
723          U+002b0 - U+002c1
724          U+0060c - U+0060d
725          U+0061e - U+00612
726          U+0064b - U+0065e
727          U+0074d - U+0076d
728          U+01800 - U+01805
729          U+01d00 - U+01d77
730          U+01d9b - U+01dbf
731          U+0200b - U+0200f
732          U+030fc - U+030fe
733          U+03260 - U+0327f
734          U+0fb46 - U+0fbb1
735          U+10450 - U+1049d
737    12. The -o option (show only the matching part of a line) for pcregrep was not
738        compatible with GNU grep in that, if there was more than one match in a
739        line, it showed only the first of them. It now behaves in the same way as
740        GNU grep.
742    13. If the -o and -v options were combined for pcregrep, it printed a blank
743        line for every non-matching line. GNU grep prints nothing, and pcregrep now
744        does the same. The return code can be used to tell if there were any
745        non-matching lines.
747    14. Added --file-offsets and --line-offsets to pcregrep.
749    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
750        infinitely looping recursion. The bug was that positive lookaheads were not
751        being skipped when checking for a possible empty match (negative lookaheads
752        and both kinds of lookbehind were skipped).
754    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
755        inclusion of <windows.h> to before rather than after the definition of
756        INVALID_FILE_ATTRIBUTES (patch from David Byron).
758    17. Specifying a possessive quantifier with a specific limit for a Unicode
759        character property caused pcre_compile() to compile bad code, which led at
760        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
761        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
762        caused the error; without that there was no problem.
764    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
766    19. Added --enable-pcretest-libreadline.
768    20. In pcrecpp.cc, the variable 'count' was incremented twice in
769        RE::GlobalReplace(). As a result, the number of replacements returned was
770        double what it should be. I removed one of the increments, but Craig sent a
771        later patch that removed the other one (the right fix) and added unit tests
772        that check the return values (which was not done before).
774    21. Several CMake things:
776        (1) Arranged that, when cmake is used on Unix, the libraries end up with
777            the names libpcre and libpcreposix, not just pcre and pcreposix.
779        (2) The above change means that pcretest and pcregrep are now correctly
780            linked with the newly-built libraries, not previously installed ones.
784    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
785        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
786        UTF-8 newline character). The key issue is that the pattern starts .*;
787        this means that the match must be either at the beginning, or after a
788        newline. The bug was in the code for advancing after a failed match and
789        checking that the new position followed a newline. It was not taking
790        account of UTF-8 characters correctly.
792    23. PCRE was behaving differently from Perl in the way it recognized POSIX
793        character classes. PCRE was not treating the sequence [:...:] as a
794        character class unless the ... were all letters. Perl, however, seems to
795        allow any characters between [: and :], though of course it rejects as
796        unknown any "names" that contain non-letters, because all the known class
797        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
798        for example, whereas PCRE did not - it did not recognize a POSIX character
799        class. This seemed a bit dangerous, so the code has been changed to be
800        closer to Perl. The behaviour is not identical to Perl, because PCRE will
801        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
802        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
803        Perl does, and where it didn't before.
805    24. Rewrite so as to remove the single use of %n from pcregrep because in some
806        Windows environments %n is disabled by default.
809    Version 7.4 21-Sep-07
810    ---------------------
812    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
813        means that a class such as [\s] counted as "explicit reference to CR or
814        LF". That isn't really right - the whole point of the change was to try to
815        help when there was an actual mention of one of the two characters. So now
816        the change happens only if \r or \n (or a literal CR or LF) character is
817        encountered.
819    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
820        of both had grown to the point where there were only 3 bits left.
821        Fortunately, there was spare space in the data structure, and so I have
822        moved the internal flags into a new 16-bit field to free up more option
823        bits.
825    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
826        but did not set the internal JCHANGED flag - either of these is enough to
827        control the way the "get" function works - but the PCRE_INFO_JCHANGED
828        facility is supposed to tell if (?J) was ever used, so now (?J) at the
829        start sets both bits.
831    4.  Added options (at build time, compile time, exec time) to change \R from
832        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
834    5.  doc/pcresyntax.html was missing from the distribution.
836    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
837        compatibility, even though it is no longer used.
839    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
840        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
841        windows.h file is present (where different names are used). [This was
842        reversed later after testing - see 16 below.]
844    8.  Changed all #include <config.h> to #include "config.h". There were also
845        some further <pcre.h> cases that I changed to "pcre.h".
847    9.  When pcregrep was used with the --colour option, it missed the line ending
848        sequence off the lines that it output.
850    10. It was pointed out to me that arrays of string pointers cause lots of
851        relocations when a shared library is dynamically loaded. A technique of
852        using a single long string with a table of offsets can drastically reduce
853        these. I have refactored PCRE in four places to do this. The result is
854        dramatic:
856          Originally:                          290
857          After changing UCP table:            187
858          After changing error message table:   43
859          After changing table of "verbs"       36
860          After changing table of Posix names   22
862        Thanks to the folks working on Gregex for glib for this insight.
864    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
865        unicode-properties was also set.
867    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
869    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
870        checked only for CRLF.
872    14. Added casts to pcretest.c to avoid compiler warnings.
874    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
876    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
877        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
878        entirely. This removes changes made in 7 above.
880    17. The CMake files have been updated, and there is now more information about
881        building with CMake in the NON-UNIX-USE document.
884    Version 7.3 28-Aug-07
885    ---------------------
887     1. In the rejigging of the build system that eventually resulted in 7.1, the
888        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
889        brackets there is not right, since it causes compilers to look for an
890        installed pcre.h, not the version that is in the source that is being
891        compiled (which of course may be different). I have changed it back to:
893          #include "pcre.h"
895        I have a vague recollection that the change was concerned with compiling in
896        different directories, but in the new build system, that is taken care of
897        by the VPATH setting the Makefile.
899     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
900        when the subject happened to end in the byte 0x85 (e.g. if the last
901        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
902        characters but of course it shouldn't be taken as a newline when it is part
903        of another character. The bug was that, for an unlimited repeat of . in
904        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
905        characters when looking for a newline.
907     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
909     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
910        in debug output.
912     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
913        long printing in the pcrecpp unittest when running under MinGW.
915     6. ESC_K was left out of the EBCDIC table.
917     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
918        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
919        limit also applies to "virtual nesting" when a pattern is recursive, and in
920        this case 1000 isn't so big. I have been able to remove this limit at the
921        expense of backing off one optimization in certain circumstances. Normally,
922        when pcre_exec() would call its internal match() function recursively and
923        immediately return the result unconditionally, it uses a "tail recursion"
924        feature to save stack. However, when a subpattern that can match an empty
925        string has an unlimited repetition quantifier, it no longer makes this
926        optimization. That gives it a stack frame in which to save the data for
927        checking that an empty string has been matched. Previously this was taken
928        from the 1000-entry workspace that had been reserved. So now there is no
929        explicit limit, but more stack is used.
931     8. Applied Daniel's patches to solve problems with the import/export magic
932        syntax that is required for Windows, and which was going wrong for the
933        pcreposix and pcrecpp parts of the library. These were overlooked when this
934        problem was solved for the main library.
936     9. There were some crude static tests to avoid integer overflow when computing
937        the size of patterns that contain repeated groups with explicit upper
938        limits. As the maximum quantifier is 65535, the maximum group length was
939        set at 30,000 so that the product of these two numbers did not overflow a
940        32-bit integer. However, it turns out that people want to use groups that
941        are longer than 30,000 bytes (though not repeat them that many times).
942        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
943        made it possible to implement the integer overflow checks in a much more
944        dynamic way, which I have now done. The artificial limitation on group
945        length has been removed - we now have only the limit on the total length of
946        the compiled pattern, which depends on the LINK_SIZE setting.
948    10. Fixed a bug in the documentation for get/copy named substring when
949        duplicate names are permitted. If none of the named substrings are set, the
950        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
951        empty string.
953    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
954        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
955        because the ] is interpreted as the first data character and the
956        terminating ] is not found. PCRE has been made compatible with Perl in this
957        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
958        cause memory overwriting.
960    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
961        string has been matched (to stop an infinite loop). It was not recognizing
962        a conditional subpattern that could match an empty string if that
963        subpattern was within another subpattern. For example, it looped when
964        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
965        condition was not nested. This bug has been fixed.
967    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
968        past the start of the subject in the presence of bytes with the top bit
969        set, for example "\x8aBCD".
971    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
972        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
974    14. Optimized (?!) to (*FAIL).
976    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
977        This restricts code points to be within the range 0 to 0x10FFFF, excluding
978        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
979        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
980        does: it's just the validity check that is more restrictive.
982    16. Inserted checks for integer overflows during escape sequence (backslash)
983        processing, and also fixed erroneous offset values for syntax errors during
984        backslash processing.
986    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
987        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
989    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
990        caused an overrun.
992    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
993        something other than just ASCII characters) inside a group that had an
994        unlimited repeat caused a loop at compile time (while checking to see
995        whether the group could match an empty string).
997    20. Debugging a pattern containing \p or \P could cause a crash. For example,
998        [\P{Any}] did so. (Error in the code for printing property names.)
1000    21. An orphan \E inside a character class could cause a crash.
1002    22. A repeated capturing bracket such as (A)? could cause a wild memory
1003        reference during compilation.
1005    23. There are several functions in pcre_compile() that scan along a compiled
1006        expression for various reasons (e.g. to see if it's fixed length for look
1007        behind). There were bugs in these functions when a repeated \p or \P was
1008        present in the pattern. These operators have additional parameters compared
1009        with \d, etc, and these were not being taken into account when moving along
1010        the compiled data. Specifically:
1012        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1013            length.
1015        (b) An item such as \pL+ within a repeated group could cause crashes or
1016            loops.
1018        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1019            "reference to non-existent subpattern" error.
1021        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1023    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1024        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1026    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1028    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1029        character were causing crashes (broken optimization).
1031    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1032        \p or \P) caused a compile-time loop.
1034    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1035        break. For example, the unstudied pattern [\r\n]A does not match the string
1036        "\r\nA" because change 7.0/46 below moves the current point on by two
1037        characters after failing to match at the start. However, the pattern \nA
1038        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1039        the same is true. There doesn't seem any very clean way out of this, but
1040        what I have chosen to do makes the common cases work: PCRE now takes note
1041        of whether there can be an explicit match for \r or \n anywhere in the
1042        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1043        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1044        pattern has explicit CR or LF references.
1046    29. Added (*CR) etc for changing newline setting at start of pattern.
1049    Version 7.2 19-Jun-07
1050    ---------------------
1052     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1053        which is apparently normally available under Windows.
1055     2. Re-jig the pcregrep tests with different newline settings in an attempt
1056        to make them independent of the local environment's newline setting.
1058     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1060     4. Some of the "internals" tests were previously cut out when the link size
1061        was not 2, because the output contained actual offsets. The recent new
1062        "Z" feature of pcretest means that these can be cut out, making the tests
1063        usable with all link sizes.
1065     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1066        stack recursion. This gives a massive performance boost under BSD, but just
1067        a small improvement under Linux. However, it saves one field in the frame
1068        in all cases.
1070     6. Added more features from the forthcoming Perl 5.10:
1072        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1073            recursion call. It refers to the nth most recently opened parentheses.
1075        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1076            to be opened parentheses.
1078        (c) Conditions that refer to capturing parentheses can be specified
1079            relatively, for example, (?(-2)... or (?(+3)...
1081        (d) \K resets the start of the current match so that everything before
1082            is not part of it.
1084        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1086        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1087            reference syntax.
1089        (g) (?| introduces a group in which the numbering of parentheses in each
1090            alternative starts with the same number.
1092        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1094     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1097     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1098        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1099        for detecting groups that can match an empty string.
1101     9. A pattern with a very large number of alternatives (more than several
1102        hundred) was running out of internal workspace during the pre-compile
1103        phase, where pcre_compile() figures out how much memory will be needed. A
1104        bit of new cunning has reduced the workspace needed for groups with
1105        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1106        workspace instead of running out of the 4096 that are available.
1108    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1110    11. Applied patch from Google to remove an optimization that didn't quite work.
1111        The report of the bug said:
1113          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1114          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1115          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1117    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1118        it matched the wrong number of bytes.
1121    Version 7.1 24-Apr-07
1122    ---------------------
1124     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1125        that is more "standard", making use of automake and other Autotools. There
1126        is some re-arrangement of the files and adjustment of comments consequent
1127        on this.
1129     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1130        for recursive directory scanning broke on some systems because the files
1131        are not scanned in any specific order and on different systems the order
1132        was different. A call to "sort" has been inserted into RunGrepTest for the
1133        approprate test as a short-term fix. In the longer term there may be an
1134        alternative.
1136     3. I had an email from Eric Raymond about problems translating some of PCRE's
1137        man pages to HTML (despite the fact that I distribute HTML pages, some
1138        people do their own conversions for various reasons). The problems
1139        concerned the use of low-level troff macros .br and .in. I have therefore
1140        removed all such uses from the man pages (some were redundant, some could
1141        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1142        HTML has been updated to handle .nf/.fi and to complain if it encounters
1143        .br or .in.
1145     4. Updated comments in configure.ac that get placed in config.h.in and also
1146        arranged for config.h to be included in the distribution, with the name
1147        config.h.generic, for the benefit of those who have to compile without
1148        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1150     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1151        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1152        makevp.bat for the current PCRE, using the additional files
1153        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1155     6. A Windows user reported a minor discrepancy with test 2, which turned out
1156        to be caused by a trailing space on an input line that had got lost in his
1157        copy. The trailing space was an accident, so I've just removed it.
1159     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1160        that is needed.
1162     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1163        as "const" (a) because they are and (b) because it helps the PHP
1164        maintainers who have recently made a script to detect big data structures
1165        in the php code that should be moved to the .rodata section. I remembered
1166        to update Builducptable as well, so it won't revert if ucptable.h is ever
1167        re-created.
1169     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1170        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1171        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1172        support is not required. This saves 1.5-2K of code, which is important in
1173        some applications.
1175        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1176        so as not to refer to the tables, even though these functions will never be
1177        called when UTF-8 support is disabled. Otherwise there are problems with a
1178        shared library.
1180    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1182        (a) It was defining its arguments as char * instead of void *.
1184        (b) It was assuming that all moves were upwards in memory; this was true
1185            a long time ago when I wrote it, but is no longer the case.
1187        The emulated memove() is provided for those environments that have neither
1188        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1189        is clearly not the case, as these two bugs were recently reported.
1191    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1192        and Detrail to create the HTML documentation, the .txt form of the man
1193        pages, and it removes trailing spaces from listed files. It also creates
1194        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1195        case, it wraps all the #defines with #ifndefs. This script should be run
1196        before "make dist".
1198    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1199        with Unicode property support.
1201        (a) For a maximizing quantifier, if the two different cases of the
1202            character were of different lengths in their UTF-8 codings (there are
1203            some cases like this - I found 11), and the matching function had to
1204            back up over a mixture of the two cases, it incorrectly assumed they
1205            were both the same length.
1207        (b) When PCRE was configured to use the heap rather than the stack for
1208            recursion during matching, it was not correctly preserving the data for
1209            the other case of a UTF-8 character when checking ahead for a match
1210            while processing a minimizing repeat. If the check also involved
1211            matching a wide character, but failed, corruption could cause an
1212            erroneous result when trying to check for a repeat of the original
1213            character.
1215    13. Some tidying changes to the testing mechanism:
1217        (a) The RunTest script now detects the internal link size and whether there
1218            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1219            values substituted by "configure". (The RunGrepTest script already did
1220            this for UTF-8.) The configure.ac script no longer substitutes the
1221            relevant variables.
1223        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1224            with length and offset values. This means that the output is different
1225            for different internal link sizes. Test 2 is skipped for link sizes
1226            other than 2 because of this, bypassing the problem. Unfortunately,
1227            there was also a test in test 3 (the locale tests) that used /B and
1228            failed for link sizes other than 2. Rather than cut the whole test out,
1229            I have added a new /Z option to pcretest that replaces the length and
1230            offset values with spaces. This is now used to make test 3 independent
1231            of link size. (Test 2 will be tidied up later.)
1233    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1234        segmentation fault instead of returning the appropriate error message.
1236    15. In multiline mode when the newline sequence was set to "any", the pattern
1237        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1238        This doesn't seem right; it now treats the CRLF combination as the line
1239        ending, and so does not match in that case. It's only a pattern such as ^$
1240        that would hit this one: something like ^ABC$ would have failed after \r
1241        and then tried again after \r\n.
1243    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1244        in an attempt to make files that differ only in their line terminators
1245        compare equal. This works on Linux.
1247    17. Under certain error circumstances pcregrep might try to free random memory
1248        as it exited. This is now fixed, thanks to valgrind.
1250    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1251        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1252        was because its rules for how to advance for /g after matching an empty
1253        string at the end of a line did not allow for this case. They now check for
1254        it specially.
1256    20. pcretest is supposed to handle patterns and data of any length, by
1257        extending its buffers when necessary. It was getting this wrong when the
1258        buffer for a data line had to be extended.
1260    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1261        CRLF as a newline sequence.
1263    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1264        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1265        I have nevertheless tidied it up.
1267    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1269    24. Added a man page for pcre-config.
1272    Version 7.0 19-Dec-06
1273    ---------------------
1275     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1276        moving to gcc 4.1.1.
1278     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1279        sys/time.h, which is documented as needed for this function. It doesn't
1280        seem to matter on Linux, but it showed up on some releases of OS X.
1282     3. It seems that there are systems where bytes whose values are greater than
1283        127 match isprint() in the "C" locale. The "C" locale should be the
1284        default when a C program starts up. In most systems, only ASCII printing
1285        characters match isprint(). This difference caused the output from pcretest
1286        to vary, making some of the tests fail. I have changed pcretest so that:
1288        (a) When it is outputting text in the compiled version of a pattern, bytes
1289            other than 32-126 are always shown as hex escapes.
1291        (b) When it is outputting text that is a matched part of a subject string,
1292            it does the same, unless a different locale has been set for the match
1293            (using the /L modifier). In this case, it uses isprint() to decide.
1295     4. Fixed a major bug that caused incorrect computation of the amount of memory
1296        required for a compiled pattern when options that changed within the
1297        pattern affected the logic of the preliminary scan that determines the
1298        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1299        that the computed length was too small. The symptoms of this bug were
1300        either the PCRE error "internal error: code overflow" from pcre_compile(),
1301        or a glibc crash with a message such as "pcretest: free(): invalid next
1302        size (fast)". Examples of patterns that provoked this bug (shown in
1303        pcretest format) are:
1305          /(?-x: )/x
1306          /(?x)(?-x: \s*#\s*)/
1307          /((?i)[\x{c0}])/8
1308          /(?i:[\x{c0}])/8
1310        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1311        is now done differently.
1313     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1314        wrapper classes; (b) implement a new function in the C++ scanner that is
1315        more efficient than the old way of doing things because it avoids levels of
1316        recursion in the regex matching; (c) add a paragraph to the documentation
1317        for the FullMatch() function.
1319     6. The escape sequence \n was being treated as whatever was defined as
1320        "newline". Not only was this contrary to the documentation, which states
1321        that \n is character 10 (hex 0A), but it also went horribly wrong when
1322        "newline" was defined as CRLF. This has been fixed.
1324     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1325        was being set to -1 for the "end of line" case (supposedly a value that no
1326        character can have). Though this value is never used (the check for end of
1327        line is "zero bytes in current character"), it caused compiler complaints.
1328        I've changed it to 0xffffffff.
1330     8. In pcre_version.c, the version string was being built by a sequence of
1331        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1332        string (as it is for production releases) called a macro with an empty
1333        argument. The C standard says the result of this is undefined. The gcc
1334        compiler treats it as an empty string (which was what was wanted) but it is
1335        reported that Visual C gives an error. The source has been hacked around to
1336        avoid this problem.
1338     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1339        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1340        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1341        of them did).
1343    10. Originally, pcretest opened its input and output without "b"; then I was
1344        told that "b" was needed in some environments, so it was added for release
1345        5.0 to both the input and output. (It makes no difference on Unix-like
1346        systems.) Later I was told that it is wrong for the input on Windows. I've
1347        now abstracted the modes into two macros, to make it easier to fiddle with
1348        them, and removed "b" from the input mode under Windows.
1350    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1352    12. Added -help and --help to pcretest as an official way of being reminded
1353        of the options.
1355    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1356        and pcrecpp.cc because they annoy compilers at high warning levels.
1358    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1360    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1361        scripts are not C programs :-) and which was not noticed because it works
1362        on Linux.
1364    16. pcretest is supposed to handle any length of pattern and data line (as one
1365        line or as a continued sequence of lines) by extending its input buffer if
1366        necessary. This feature was broken for very long pattern lines, leading to
1367        a string of junk being passed to pcre_compile() if the pattern was longer
1368        than about 50K.
1370    17. I have done a major re-factoring of the way pcre_compile() computes the
1371        amount of memory needed for a compiled pattern. Previously, there was code
1372        that made a preliminary scan of the pattern in order to do this. That was
1373        OK when PCRE was new, but as the facilities have expanded, it has become
1374        harder and harder to keep it in step with the real compile phase, and there
1375        have been a number of bugs (see for example, 4 above). I have now found a
1376        cunning way of running the real compile function in a "fake" mode that
1377        enables it to compute how much memory it would need, while actually only
1378        ever using a few hundred bytes of working memory and without too many
1379        tests of the mode. This should make future maintenance and development
1380        easier. A side effect of this work is that the limit of 200 on the nesting
1381        depth of parentheses has been removed (though this was never a serious
1382        limitation, I suspect). However, there is a downside: pcre_compile() now
1383        runs more slowly than before (30% or more, depending on the pattern). I
1384        hope this isn't a big issue. There is no effect on runtime performance.
1386    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1387        newline (only possible for the last line of a file) and it was a
1388        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1390    19. Added additional timing features to pcretest. (1) The -tm option now times
1391        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1392        separate command line item, by a number that specifies the number of
1393        repeats to use when timing. The default is 50000; this gives better
1394        precision, but takes uncomfortably long for very large patterns.
1396    20. Extended pcre_study() to be more clever in cases where a branch of a
1397        subpattern has no definite first character. For example, (a*|b*)[cd] would
1398        previously give no result from pcre_study(). Now it recognizes that the
1399        first character must be a, b, c, or d.
1401    21. There was an incorrect error "recursive call could loop indefinitely" if
1402        a subpattern (or the entire pattern) that was being tested for matching an
1403        empty string contained only one non-empty item after a nested subpattern.
1404        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1405        incorrectly, because the \d was being skipped in the check.
1407    22. The pcretest program now has a new pattern option /B and a command line
1408        option -b, which is equivalent to adding /B to every pattern. This causes
1409        it to show the compiled bytecode, without the additional information that
1410        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1411        is the same as /B/I).
1413    23. A new optimization is now able automatically to treat some sequences such
1414        as a*b as a*+b. More specifically, if something simple (such as a character
1415        or a simple class like \d) has an unlimited quantifier, and is followed by
1416        something that cannot possibly match the quantified thing, the quantifier
1417        is automatically "possessified".
1419    24. A recursive reference to a subpattern whose number was greater than 39
1420        went wrong under certain circumstances in UTF-8 mode. This bug could also
1421        have affected the operation of pcre_study().
1423    25. Realized that a little bit of performance could be had by replacing
1424        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1426    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1428    27. Possessive quantifiers such as a++ were previously implemented by turning
1429        them into atomic groups such as ($>a+). Now they have their own opcodes,
1430        which improves performance. This includes the automatically created ones
1431        from 23 above.
1433    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1434        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1435        the first matched character to be a colon. This applied both to named and
1436        numbered groups.
1438    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1440    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1441        building PCRE on Windows easier, so I have included it in the distribution.
1443    31. There is now a check in pcretest against a ridiculously large number being
1444        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1445        loop, the loop is abandoned.
1447    32. Forward references to subpatterns in conditions such as (?(2)...) where
1448        subpattern 2 is defined later cause pcre_compile() to search forwards in
1449        the pattern for the relevant set of parentheses. This search went wrong
1450        when there were unescaped parentheses in a character class, parentheses
1451        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1453    33. "Subroutine" calls and backreferences were previously restricted to
1454        referencing subpatterns earlier in the regex. This restriction has now
1455        been removed.
1457    34. Added a number of extra features that are going to be in Perl 5.10. On the
1458        whole, these are just syntactic alternatives for features that PCRE had
1459        previously implemented using the Python syntax or my own invention. The
1460        other formats are all retained for compatibility.
1462        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1463            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1464            also .NET compatible.
1466        (b) A recursion or subroutine call to a named group can now be defined as
1467            (?&name) as well as (?P>name).
1469        (c) A backreference to a named group can now be defined as \k<name> or
1470            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1471            5.10, are also .NET compatible.
1473        (d) A conditional reference to a named group can now use the syntax
1474            (?(<name>) or (?('name') as well as (?(name).
1476        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1477            groups (named and numbered) that are never evaluated inline, but can be
1478            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1479            is always false. There may be only one alternative in such a group.
1481        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1482            as the simple (?(R). The condition is true only if the most recent
1483            recursion is that of the given number or name. It does not search out
1484            through the entire recursion stack.
1486        (g) The escape \gN or \g{N} has been added, where N is a positive or
1487            negative number, specifying an absolute or relative reference.
1489    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1490        some "unreachable code" warnings.
1492    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1493        things, this adds five new scripts.
1495    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1496        There were also incompatibilities regarding the handling of \Q..\E inside
1497        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1498        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1500    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1501        matches an empty string, and forcibly breaks the loop. There were bugs in
1502        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1503        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1504        separate and independent bugs (that affected different cases) have been
1505        fixed.
1507    39. Refactored the code to abolish the use of different opcodes for small
1508        capturing bracket numbers. This is a tidy that I avoided doing when I
1509        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1510        The new approach is not only tidier, it makes it possible to reduce the
1511        memory needed to fix the previous bug (38).
1513    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1514        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1515        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1516        mode.
1518    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1519        report.
1521    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1522        copy construction and assignment in the C++ wrapper.
1524    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1525        couple of bugs that could have given wrong results in the "--newline=crlf"
1526        case.
1528    44. Added a number of casts and did some reorganization of signed/unsigned int
1529        variables following suggestions from Dair Grant. Also renamed the variable
1530        "this" as "item" because it is a C++ keyword.
1532    45. Arranged for dftables to add
1534          #include "pcre_internal.h"
1536        to pcre_chartables.c because without it, gcc 4.x may remove the array
1537        definition from the final binary if PCRE is built into a static library and
1538        dead code stripping is activated.
1540    46. For an unanchored pattern, if a match attempt fails at the start of a
1541        newline sequence, and the newline setting is CRLF or ANY, and the next two
1542        characters are CRLF, advance by two characters instead of one.
1545    Version 6.7 04-Jul-06
1546    ---------------------
1548     1. In order to handle tests when input lines are enormously long, pcretest has
1549        been re-factored so that it automatically extends its buffers when
1550        necessary. The code is crude, but this _is_ just a test program. The
1551        default size has been increased from 32K to 50K.
1553     2. The code in pcre_study() was using the value of the re argument before
1554        testing it for NULL. (Of course, in any sensible call of the function, it
1555        won't be NULL.)
1557     3. The memmove() emulation function in pcre_internal.h, which is used on
1558        systems that lack both memmove() and bcopy() - that is, hardly ever -
1559        was missing a "static" storage class specifier.
1561     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1562        containing an extended class (one that cannot be represented by a bitmap
1563        because it contains high-valued characters or Unicode property items, e.g.
1564        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1565        pattern, but PCRE should not loop if you do not (it no longer does).
1566        [Detail: two cases were found: (a) a repeated subpattern containing an
1567        extended class; (b) a recursive reference to a subpattern that followed a
1568        previous extended class. It wasn't skipping over the extended class
1569        correctly when UTF-8 mode was not set.]
1571     5. A negated single-character class was not being recognized as fixed-length
1572        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1573        compile error "lookbehind assertion is not fixed length".
1575     6. The RunPerlTest auxiliary script was showing an unexpected difference
1576        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1577        write a Perl script that can interpret lines of an input file either as
1578        byte characters or as UTF-8, which is what "perltest" was being required to
1579        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1580        can't do is switch easily at run time between having the "use utf8;" pragma
1581        or not. In the end, I fudged it by using the RunPerlTest script to insert
1582        "use utf8;" explicitly for the UTF-8 tests.
1584     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1585        the end of the subject string, contrary to the documentation and to what
1586        Perl does. This was true of both matching functions. Now it matches only at
1587        the start of the subject and immediately after *internal* newlines.
1589     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1590        a pointer to an int instead of a pointer to an unsigned long int. This
1591        caused problems on 64-bit systems.
1593     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1594        instance of the 'standard' template library not being so standard".
1596    10. There was no check on the number of named subpatterns nor the maximum
1597        length of a subpattern name. The product of these values is used to compute
1598        the size of the memory block for a compiled pattern. By supplying a very
1599        long subpattern name and a large number of named subpatterns, the size
1600        computation could be caused to overflow. This is now prevented by limiting
1601        the length of names to 32 characters, and the number of named subpatterns
1602        to 10,000.
1604    11. Subpatterns that are repeated with specific counts have to be replicated in
1605        the compiled pattern. The size of memory for this was computed from the
1606        length of the subpattern and the repeat count. The latter is limited to
1607        65535, but there was no limit on the former, meaning that integer overflow
1608        could in principle occur. The compiled length of a repeated subpattern is
1609        now limited to 30,000 bytes in order to prevent this.
1611    12. Added the optional facility to have named substrings with the same name.
1613    13. Added the ability to use a named substring as a condition, using the
1614        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1615        are numbers (not recommended). Forward references are permitted.
1617    14. Added forward references in named backreferences (if you see what I mean).
1619    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1620        pattern could run off the end of the subject. For example, the pattern
1621        "(?s)(.{1,5})"8 did this with the subject "ab".
1623    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1624        PCRE_CASELESS was set when matching characters that were quantified with ?
1625        or *.
1627    17. A character class other than a single negated character that had a minimum
1628        but no maximum quantifier - for example [ab]{6,} - was not handled
1629        correctly by pce_dfa_exec(). It would match only one character.
1631    18. A valid (though odd) pattern that looked like a POSIX character
1632        class but used an invalid character after [ (for example [[,abc,]]) caused
1633        pcre_compile() to give the error "Failed: internal error: code overflow" or
1634        in some cases to crash with a glibc free() error. This could even happen if
1635        the pattern terminated after [[ but there just happened to be a sequence of
1636        letters, a binary zero, and a closing ] in the memory that followed.
1638    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1639        over the years. Originally (before any Unicode support), just the bottom 8
1640        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1641        output from "man perlunicode" includes this:
1643          The regular expression compiler produces polymorphic opcodes.  That
1644          is, the pattern adapts to the data and automatically switches to
1645          the Unicode character scheme when presented with Unicode data--or
1646          instead uses a traditional byte scheme when presented with byte
1647          data.
1649        Sadly, a wide octal escape does not cause a switch, and in a string with
1650        no other multibyte characters, these octal escapes are treated as before.
1651        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1652        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1653        Unicode string.
1655        I have not perpetrated such confusion in PCRE. Up till now, it took just
1656        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1657        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1658        translate to the appropriate multibyte character.
1660    29. Applied some refactoring to reduce the number of warnings from Microsoft
1661        and Borland compilers. This has included removing the fudge introduced
1662        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1663        a warning about an unused variable.
1665    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1666        characters since release 4.0, because Perl (from release 5.004) does not.
1667        [Or at least, is documented not to: some releases seem to be in conflict
1668        with the documentation.] However, when a pattern was studied with
1669        pcre_study() and all its branches started with \s, PCRE still included VT
1670        as a possible starting character. Of course, this did no harm; it just
1671        caused an unnecessary match attempt.
1673    22. Removed a now-redundant internal flag bit that recorded the fact that case
1674        dependency changed within the pattern. This was once needed for "required
1675        byte" processing, but is no longer used. This recovers a now-scarce options
1676        bit. Also moved the least significant internal flag bit to the most-
1677        significant bit of the word, which was not previously used (hangover from
1678        the days when it was an int rather than a uint) to free up another bit for
1679        the future.
1681    23. Added support for CRLF line endings as well as CR and LF. As well as the
1682        default being selectable at build time, it can now be changed at runtime
1683        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1684        specify that it is scanning data with non-default line endings.
1686    24. Changed the definition of CXXLINK to make it agree with the definition of
1687        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1689    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1690        recursions. This makes a big different to stack usage for some patterns.
1692    26. If a subpattern containing a named recursion or subroutine reference such
1693        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1694        the space required for the compiled pattern went wrong and gave too small a
1695        value. Depending on the environment, this could lead to "Failed: internal
1696        error: code overflow at offset 49" or "glibc detected double free or
1697        corruption" errors.
1699    27. Applied patches from Google (a) to support the new newline modes and (b) to
1700        advance over multibyte UTF-8 characters in GlobalReplace.
1702    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1703        difference for some implementation of PCRE in some Windows version.
1705    29. Added some extra testing facilities to pcretest:
1707        \q<number>   in a data line sets the "match limit" value
1708        \Q<number>   in a data line sets the "match recursion limt" value
1709        -S <number>  sets the stack size, where <number> is in megabytes
1711        The -S option isn't available for Windows.
1714    Version 6.6 06-Feb-06
1715    ---------------------
1717     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1718        in pcreposix.h. I have copied the definition from pcre.h.
1720     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1721        because pcre.h is no longer a built file.
1723     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1724        not normally included in the compiled code.
1727    Version 6.5 01-Feb-06
1728    ---------------------
1730     1. When using the partial match feature with pcre_dfa_exec(), it was not
1731        anchoring the second and subsequent partial matches at the new starting
1732        point. This could lead to incorrect results. For example, with the pattern
1733        /1234/, partially matching against "123" and then "a4" gave a match.
1735     2. Changes to pcregrep:
1737        (a) All non-match returns from pcre_exec() were being treated as failures
1738            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1739            error message is output. Some extra information is given for the
1740            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1741            probably the only errors that are likely to be caused by users (by
1742            specifying a regex that has nested indefinite repeats, for instance).
1743            If there are more than 20 of these errors, pcregrep is abandoned.
1745        (b) A binary zero was treated as data while matching, but terminated the
1746            output line if it was written out. This has been fixed: binary zeroes
1747            are now no different to any other data bytes.
1749        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1750            used to set a locale for matching. The --locale=xxxx long option has
1751            been added (no short equivalent) to specify a locale explicitly on the
1752            pcregrep command, overriding the environment variables.
1754        (d) When -B was used with -n, some line numbers in the output were one less
1755            than they should have been.
1757        (e) Added the -o (--only-matching) option.
1759        (f) If -A or -C was used with -c (count only), some lines of context were
1760            accidentally printed for the final match.
1762        (g) Added the -H (--with-filename) option.
1764        (h) The combination of options -rh failed to suppress file names for files
1765            that were found from directory arguments.
1767        (i) Added the -D (--devices) and -d (--directories) options.
1769        (j) Added the -F (--fixed-strings) option.
1771        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1773        (l) Added the --colo(u)r option.
1775        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1776            is not present by default.
1778     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1779        items such as (?R) or (?1), when the recursion could match a number of
1780        alternatives. If it matched one of the alternatives, but subsequently,
1781        outside the recursion, there was a failure, the code tried to back up into
1782        the recursion. However, because of the way PCRE is implemented, this is not
1783        possible, and the result was an incorrect result from the match.
1785        In order to prevent this happening, the specification of recursion has
1786        been changed so that all such subpatterns are automatically treated as
1787        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1789     4. I had overlooked the fact that, in some locales, there are characters for
1790        which isalpha() is true but neither isupper() nor islower() are true. In
1791        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1792        and ordfeminine) are like this. This affected the treatment of \w and \W
1793        when they appeared in character classes, but not when they appeared outside
1794        a character class. The bit map for "word" characters is now created
1795        separately from the results of isalnum() instead of just taking it from the
1796        upper, lower, and digit maps. (Plus the underscore character, of course.)
1798     5. The above bug also affected the handling of POSIX character classes such as
1799        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1800        permanent tables. Instead, the bit maps for such a class were previously
1801        created as the appropriate unions of the upper, lower, and digit bitmaps.
1802        Now they are created by subtraction from the [[:word:]] class, which has
1803        its own bitmap.
1805     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1806        It is created by subtracting the vertical space characters (\x09, \x0a,
1807        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1808        subtraction was done in the overall bitmap for a character class, meaning
1809        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1810        be recognized. This bug has been fixed.
1812     7. Patches from the folks at Google:
1814          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1815          real life, but is still worth protecting against".
1817          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1818          regular expressions".
1820          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1821          have it.
1823          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1824          "configure" and the latter not, in order to fix a problem somebody had
1825          with compiling the Arg class on HP-UX.
1827          (e) Improve the error-handling of the C++ wrapper a little bit.
1829          (f) New tests for checking recursion limiting.
1831     8. The pcre_memmove() function, which is used only if the environment does not
1832        have a standard memmove() function (and is therefore rarely compiled),
1833        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1834        returning a result (though PCRE never actually uses the result).
1836     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1837        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1838        returned instead of calling malloc() with an overflowing number that would
1839        most likely cause subsequent chaos.
1841    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1843    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1844        with this option is matched, the nmatch and pmatch options of regexec() are
1845        ignored.
1847    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1848        provided in case anyone wants to the the POSIX interface with UTF-8
1849        strings.
1851    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1852        C++ linking (needed for some HP-UX environments).
1854    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1855        (unused parameter) and in the pcre_printint() function (omitted "default"
1856        switch label when the default is to do nothing).
1858    15. Added some code to make it possible, when PCRE is compiled as a C++
1859        library, to replace subject pointers for pcre_exec() with a smart pointer
1860        class, thus making it possible to process discontinuous strings.
1862    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1863        much the same function. They were added by different people who were trying
1864        to make PCRE easy to compile on non-Unix systems. It has been suggested
1865        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1866        for compiling on Windows systems. I have therefore replaced it with
1867        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1868        defaults to "extern" for C or "extern C" for C++, which works fine on
1869        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1870        SCOPE with something explicit in config.h. In addition:
1872        (a) pcreposix.h still had just "extern" instead of either of these macros;
1873            I have replaced it with PCRE_DATA_SCOPE.
1875        (b) Functions such as _pcre_xclass(), which are internal to the library,
1876            but external in the C sense, all had PCRE_EXPORT in their definitions.
1877            This is apparently wrong for the Windows case, so I have removed it.
1878            (It makes no difference on Unix-like systems.)
1880    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1881        of recursive calls to match(). This is different to MATCH_LIMIT because
1882        that limits the total number of calls to match(), not all of which increase
1883        the depth of recursion. Limiting the recursion depth limits the amount of
1884        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1885        when PCRE is compiled, and changed at run time. A patch from Google adds
1886        this functionality to the C++ interface.
1888    18. Changes to the handling of Unicode character properties:
1890        (a) Updated the table to Unicode 4.1.0.
1892        (b) Recognize characters that are not in the table as "Cn" (undefined).
1894        (c) I revised the way the table is implemented to a much improved format
1895            which includes recognition of ranges. It now supports the ranges that
1896            are defined in UnicodeData.txt, and it also amalgamates other
1897            characters into ranges. This has reduced the number of entries in the
1898            table from around 16,000 to around 3,000, thus reducing its size
1899            considerably. I realized I did not need to use a tree structure after
1900            all - a binary chop search is just as efficient. Having reduced the
1901            number of entries, I extended their size from 6 bytes to 8 bytes to
1902            allow for more data.
1904        (d) Added support for Unicode script names via properties such as \p{Han}.
1906    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1907        matching that character.
1909    20. When matching a repeated Unicode property with a minimum greater than zero,
1910        (for example \pL{2,}), PCRE could look past the end of the subject if it
1911        reached it while seeking the minimum number of characters. This could
1912        happen only if some of the characters were more than one byte long, because
1913        there is a check for at least the minimum number of bytes.
1915    21. Refactored the implementation of \p and \P so as to be more general, to
1916        allow for more different types of property in future. This has changed the
1917        compiled form incompatibly. Anybody with saved compiled patterns that use
1918        \p or \P will have to recompile them.
1920    22. Added "Any" and "L&" to the supported property types.
1922    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1923        but give a compile time error if the value is greater than 0xff.
1925    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1926        accidentally not being installed or uninstalled.
1928    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1929        made were to insert the current release number. This seemed silly, because
1930        it made things harder for people building PCRE on systems that don't run
1931        "configure". I have turned pcre.h into a distributed file, no longer built
1932        by "configure", with the version identification directly included. There is
1933        no longer a pcre.h.in file.
1935        However, this change necessitated a change to the pcre-config script as
1936        well. It is built from pcre-config.in, and one of the substitutions was the
1937        release number. I have updated configure.ac so that ./configure now finds
1938        the release number by grepping pcre.h.
1940    26. Added the ability to run the tests under valgrind.
1943    Version 6.4 05-Sep-05
1944    ---------------------
1946     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1947        "--" to be printed when multiple files were scanned, even when none of the
1948        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1949        consider it to be a bug, and have restored the previous behaviour.
1951     2. A couple of code tidies to get rid of compiler warnings.
1953     3. The pcretest program used to cheat by referring to symbols in the library
1954        whose names begin with _pcre_. These are internal symbols that are not
1955        really supposed to be visible externally, and in some environments it is
1956        possible to suppress them. The cheating is now confined to including
1957        certain files from the library's source, which is a bit cleaner.
1959     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1960        file's purpose clearer.
1962     5. Reorganized pcre_ucp_findchar().
1965    Version 6.3 15-Aug-05
1966    ---------------------
1968     1. The file libpcre.pc.in did not have general read permission in the tarball.
1970     2. There were some problems when building without C++ support:
1972        (a) If C++ support was not built, "make install" and "make test" still
1973            tried to test it.
1975        (b) There were problems when the value of CXX was explicitly set. Some
1976            changes have been made to try to fix these, and ...
1978        (c) --disable-cpp can now be used to explicitly disable C++ support.
1980        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1981            backslash in a target when C++ was disabled. This confuses some
1982            versions of "make", apparently. Using an intermediate variable solves
1983            this. (Same for CPP_LOBJ.)
1985     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1986        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1987        necessary on certain architectures.
1989     4. Added a setting of -export-symbols-regex to the link command to remove
1990        those symbols that are exported in the C sense, but actually are local
1991        within the library, and not documented. Their names all begin with
1992        "_pcre_". This is not a perfect job, because (a) we have to except some
1993        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1994        available (and never for static libraries). I have made a note to try to
1995        find a way round (a) in the future.
1998    Version 6.2 01-Aug-05
1999    ---------------------
2001     1. There was no test for integer overflow of quantifier values. A construction
2002        such as {1111111111111111} would give undefined results. What is worse, if
2003        a minimum quantifier for a parenthesized subpattern overflowed and became
2004        negative, the calculation of the memory size went wrong. This could have
2005        led to memory overwriting.
2007     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2009     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2010        operating environments where this matters.
2012     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2013        PCRE options from within the C++ wrapper.
2015     5. Named capturing subpatterns were not being correctly counted when a pattern
2016        was compiled. This caused two problems: (a) If there were more than 100
2017        such subpatterns, the calculation of the memory needed for the whole
2018        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2019        back references of the form \12, where the number was greater than 9, were
2020        not recognized as back references, even though there were sufficient
2021        previous subpatterns.
2023     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2024        versions of gcc, e.g. 2.95.4.
2027    Version 6.1 21-Jun-05
2028    ---------------------
2030     1. There was one reference to the variable "posix" in pcretest.c that was not
2031        surrounded by "#if !defined NOPOSIX".
2033     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2034        the cross-check on the old pcre_info() function, for the benefit of the
2035        cut-down version of PCRE that is currently imported into Exim.
2037     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2038        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2039        patterns that start (?i) but I don't think that matters. The use of (?i) is
2040        just an example; this all applies to the other options as well.
2042     4. Since libtool seems to echo the compile commands it is issuing, the output
2043        from "make" can be reduced a bit by putting "@" in front of each libtool
2044        compile command.
2046     5. Patch from the folks at Google for configure.in to be a bit more thorough
2047        in checking for a suitable C++ installation before trying to compile the
2048        C++ stuff. This should fix a reported problem when a compiler was present,
2049        but no suitable headers.
2051     6. The man pages all had just "PCRE" as their title. I have changed them to
2052        be the relevant file name. I have also arranged that these names are
2053        retained in the file doc/pcre.txt, which is a concatenation in text format
2054        of all the man pages except the little individual ones for each function.
2056     7. The NON-UNIX-USE file had not been updated for the different set of source
2057        files that come with release 6. I also added a few comments about the C++
2058        wrapper.
2061    Version 6.0 07-Jun-05
2062    ---------------------
2064     1. Some minor internal re-organization to help with my DFA experiments.
2066     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2067        didn't matter for the library itself when fully configured, but did matter
2068        when compiling without UCP support, or within Exim, where the ucp files are
2069        not imported.
2071     3. Refactoring of the library code to split up the various functions into
2072        different source modules. The addition of the new DFA matching code (see
2073        below) to a single monolithic source would have made it really too
2074        unwieldy, quite apart from causing all the code to be include in a
2075        statically linked application, when only some functions are used. This is
2076        relevant even without the DFA addition now that patterns can be compiled in
2077        one application and matched in another.
2079        The downside of splitting up is that there have to be some external
2080        functions and data tables that are used internally in different modules of
2081        the library but which are not part of the API. These have all had their
2082        names changed to start with "_pcre_" so that they are unlikely to clash
2083        with other external names.
2085     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2086        a different (DFA) algorithm. Although it is slower than the original
2087        function, it does have some advantages for certain types of matching
2088        problem.
2090     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2091        including restarting after a partial match.
2093     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2094        defined when compiling for Windows was sent to me. I have put it into the
2095        code, though I have no means of testing or verifying it.
2097     7. Added the pcre_refcount() auxiliary function.
2099     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2100        match before or at the first newline in the subject string. In pcretest,
2101        the /f option on a pattern can be used to set this.
2103     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2104        would behave wrongly. This has been present in PCRE since release 4.0.
2106    10. A number of changes to the pcregrep command:
2108        (a) Refactored how -x works; insert ^(...)$ instead of setting
2109            PCRE_ANCHORED and checking the length, in preparation for adding
2110            something similar for -w.
2112        (b) Added the -w (match as a word) option.
2114        (c) Refactored the way lines are read and buffered so as to have more
2115            than one at a time available.
2117        (d) Implemented a pcregrep test script.
2119        (e) Added the -M (multiline match) option. This allows patterns to match
2120            over several lines of the subject. The buffering ensures that at least
2121            8K, or the rest of the document (whichever is the shorter) is available
2122            for matching (and similarly the previous 8K for lookbehind assertions).
2124        (f) Changed the --help output so that it now says
2126              -w, --word-regex(p)
2128            instead of two lines, one with "regex" and the other with "regexp"
2129            because that confused at least one person since the short forms are the
2130            same. (This required a bit of code, as the output is generated
2131            automatically from a table. It wasn't just a text change.)
2133        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2134            option but starts with a hyphen. Could be a pattern or a path name
2135            starting with a hyphen, for instance.
2137        (h) "-" can be given as a file name to represent stdin.
2139        (i) When file names are being printed, "(standard input)" is used for
2140            the standard input, for compatibility with GNU grep. Previously
2141            "<stdin>" was used.
2143        (j) The option --label=xxx can be used to supply a name to be used for
2144            stdin when file names are being printed. There is no short form.
2146        (k) Re-factored the options decoding logic because we are going to add
2147            two more options that take data. Such options can now be given in four
2148            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2150        (l) Added the -A, -B, and -C options for requesting that lines of context
2151            around matches be printed.
2153        (m) Added the -L option to print the names of files that do not contain
2154            any matching lines, that is, the complement of -l.
2156        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2157            continue to scan other files.
2159        (o) The -s option was incorrectly implemented. For compatibility with other
2160            greps, it now suppresses the error message for a non-existent or non-
2161            accessible file (but not the return code). There is a new option called
2162            -q that suppresses the output of matching lines, which was what -s was
2163            previously doing.
2165        (p) Added --include and --exclude options to specify files for inclusion
2166            and exclusion when recursing.
2168    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2169        Hopefully, it now does.
2171    12. Missing cast in pcre_study().
2173    13. Added an "uninstall" target to the makefile.
2175    14. Replaced "extern" in the function prototypes in Makefile.in with
2176        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2177        world, but is set differently for Windows.
2179    15. Added a second compiling function called pcre_compile2(). The only
2180        difference is that it has an extra argument, which is a pointer to an
2181        integer error code. When there is a compile-time failure, this is set
2182        non-zero, in addition to the error test pointer being set to point to an
2183        error message. The new argument may be NULL if no error number is required
2184        (but then you may as well call pcre_compile(), which is now just a
2185        wrapper). This facility is provided because some applications need a
2186        numeric error indication, but it has also enabled me to tidy up the way
2187        compile-time errors are handled in the POSIX wrapper.
2189    16. Added VPATH=.libs to the makefile; this should help when building with one
2190        prefix path and installing with another. (Or so I'm told by someone who
2191        knows more about this stuff than I do.)
2193    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2194        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2195        match everything, including newlines. This is not POSIX-compatible, but
2196        somebody wanted the feature. From pcretest it can be activated by using
2197        both the P and the s flags.
2199    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2201    19. libpcre.pc was being incorrectly installed as executable.
2203    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2204        it now also looks for '\r' so that it will work unmodified on Windows.
2206    21. Added Google's contributed C++ wrapper to the distribution.
2208    22. Added some untidy missing memory free() calls in pcretest, to keep
2209        Electric Fence happy when testing.
2213    Version 5.0 13-Sep-04
2214    ---------------------
2216     1. Internal change: literal characters are no longer packed up into items
2217        containing multiple characters in a single byte-string. Each character
2218        is now matched using a separate opcode. However, there may be more than one
2219        byte in the character in UTF-8 mode.
2221     2. The pcre_callout_block structure has two new fields: pattern_position and
2222        next_item_length. These contain the offset in the pattern to the next match
2223        item, and its length, respectively.
2225     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2226        insertion of callouts before each pattern item. Added the /C option to
2227        pcretest to make use of this.
2229     4. On the advice of a Windows user, the lines
2231          #if defined(_WIN32) || defined(WIN32)
2232          _setmode( _fileno( stdout ), 0x8000 );
2233          #endif  /* defined(_WIN32) || defined(WIN32) */
2235        have been added to the source of pcretest. This apparently does useful
2236        magic in relation to line terminators.
2238     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2239        for the benefit of those environments where the "b" makes a difference.
2241     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2242        to know about it. I have put a hack into configure.in that adds in code
2243        to set GCC=yes if CC=icc. This seems to end up at a point in the
2244        generated configure script that is early enough to affect the setting of
2245        compiler options, which is what is needed, but I have no means of testing
2246        whether it really works. (The user who reported this had patched the
2247        generated configure script, which of course I cannot do.)
2249        LATER: After change 22 below (new libtool files), the configure script
2250        seems to know about icc (and also ecc). Therefore, I have commented out
2251        this hack in configure.in.
2253     7. Added support for pkg-config (2 patches were sent in).
2255     8. Negated POSIX character classes that used a combination of internal tables
2256        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2257        [[:^ascii]]. Typically, they would match almost any characters. The other
2258        POSIX classes were not broken in this way.
2260     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2261        to find the match, as PCRE was deluded into thinking that the match had to
2262        start at the start point or following a newline. The same bug applied to
2263        patterns with negative forward assertions or any backward assertions
2264        preceding ".*" at the start, unless the pattern required a fixed first
2265        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2267    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2268        starting at the last subject character, bytes beyond the end of the subject
2269        string were read.
2271    11. Renamed the variable "class" as "classbits" to make life easier for C++
2272        users. (Previously there was a macro definition, but it apparently wasn't
2273        enough.)
2275    12. Added the new field "tables" to the extra data so that tables can be passed
2276        in at exec time, or the internal tables can be re-selected. This allows
2277        a compiled regex to be saved and re-used at a later time by a different
2278        program that might have everything at different addresses.
2280    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2281        -R library as well as a -L library.
2283    14. The debugging options of pcretest (-d on the command line or D on a
2284        pattern) showed incorrect output for anything following an extended class
2285        that contained multibyte characters and which was followed by a quantifier.
2287    15. Added optional support for general category Unicode character properties
2288        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2289        support. It adds about 90K to the size of the library. The meanings of the
2290        inbuilt class escapes such as \d and \s have NOT been changed.
2292    16. Updated pcredemo.c to include calls to free() to release the memory for the
2293        compiled pattern.
2295    17. The generated file chartables.c was being created in the source directory
2296        instead of in the building directory. This caused the build to fail if the
2297        source directory was different from the building directory, and was
2298        read-only.
2300    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2301        file. No doubt somebody will tell me if they don't make sense... Also added
2302        Dan Mooney's comments about building on OpenVMS.
2304    19. Added support for partial matching via the PCRE_PARTIAL option for
2305        pcre_exec() and the \P data escape in pcretest.
2307    20. Extended pcretest with 3 new pattern features:
2309        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2310              write the compiled pattern to the file whose name is "rest-of-line".
2311              This is a straight binary dump of the data, with the saved pointer to
2312              the character tables forced to be NULL. The study data, if any, is
2313              written too. After writing, pcretest reads a new pattern.
2315        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2316              compiled pattern from the given file. There must not be any
2317              occurrences of "<" in the file name (pretty unlikely); if there are,
2318              pcretest will instead treat the initial "<" as a pattern delimiter.
2319              After reading in the pattern, pcretest goes on to read data lines as
2320              usual.
2322        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2323              and 16-bit fields in a compiled pattern, to simulate a pattern that
2324              was compiled on a host of opposite endianness.
2326    21. The pcre-exec() function can now cope with patterns that were compiled on
2327        hosts of opposite endianness, with this restriction:
2329          As for any compiled expression that is saved and used later, the tables
2330          pointer field cannot be preserved; the extra_data field in the arguments
2331          to pcre_exec() should be used to pass in a tables address if a value
2332          other than the default internal tables were used at compile time.
2334    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2335        now diagnosed as an error. Previously, most of the time, a negative number
2336        would have been treated as zero, but if in addition "ovector" was passed as
2337        NULL, a crash could occur.
2339    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2340        new versions from the libtool 1.5 distribution (the last one is a copy of
2341        a file called libtool.m4). This seems to have fixed the need to patch
2342        "configure" to support Darwin 1.3 (which I used to do). However, I still
2343        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2344        workstation).
2346    24. Changed the PCRE licence to be the more standard "BSD" licence.
2349    Version 4.5 01-Dec-03
2350    ---------------------
2352     1. There has been some re-arrangement of the code for the match() function so
2353        that it can be compiled in a version that does not call itself recursively.
2354        Instead, it keeps those local variables that need separate instances for
2355        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2356        needs to "recurse". Keeping track of where control must go is done by means
2357        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2358        hide most of the details from the main code, and operates only if
2359        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2360        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2361        operating.
2363        To make it easier for callers to provide specially tailored get/free
2364        functions for this usage, two new functions, pcre_stack_malloc, and
2365        pcre_stack_free, are used. They are always called in strict stacking order,
2366        and the size of block requested is always the same.
2368        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2369        PCRE has been compiled to use the stack or the heap for recursion. The
2370        -C option of pcretest uses this to show which version is compiled.
2372        A new data escape \S, is added to pcretest; it causes the amounts of store
2373        obtained and freed by both kinds of malloc/free at match time to be added
2374        to the output.
2376     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2377        what's available on my current Linux desktop machine.
2379     3. When matching a UTF-8 string, the test for a valid string at the start has
2380        been extended. If start_offset is not zero, PCRE now checks that it points
2381        to a byte that is the start of a UTF-8 character. If not, it returns
2382        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2383        this is necessary because there may be backward assertions in the pattern.
2384        When matching the same subject several times, it may save resources to use
2385        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2387     4. The code for checking the validity of UTF-8 strings has been tightened so
2388        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2389        containing "overlong sequences".
2391     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2392        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2393        should have been "&", but it just so happened that all the cases this let
2394        through by mistake were picked up later in the function.
2396     6. I had used a variable called "isblank" - this is a C99 function, causing
2397        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2399     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2400        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2401        so the version is shown; (c) stop "make test" echoing "./RunTest".
2403     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2405     9. The prototype for memmove() for systems that don't have it was using
2406        size_t, but the inclusion of the header that defines size_t was later. I've
2407        moved the #includes for the C headers earlier to avoid this.
2409    10. Added some adjustments to the code to make it easier to compiler on certain
2410        special systems:
2412          (a) Some "const" qualifiers were missing.
2413          (b) Added the macro EXPORT before all exported functions; by default this
2414              is defined to be empty.
2415          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2416              that it reads its output file name as an argument instead of writing
2417              to the standard output and assuming this can be redirected.
2419    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2420        class containing characters with values greater than 255, PCRE compilation
2421        went into a loop.
2423    12. A recursive reference to a subpattern that was within another subpattern
2424        that had a minimum quantifier of zero caused PCRE to crash. For example,
2425        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2426        recursion. If the recursively-called subpattern itself had a zero repeat,
2427        that was OK.
2429    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2430        buffer into which it was copied (for escape processing) was still set at
2431        1024, so long lines caused crashes.
2433    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2434        "internal error: code overflow...". This applied to any character class
2435        that was followed by a possessive quantifier.
2437    15. Modified the Makefile to add libpcre.la as a prerequisite for
2438        libpcreposix.la because I was told this is needed for a parallel build to
2439        work.
2441    16. If a pattern that contained .* following optional items at the start was
2442        studied, the wrong optimizing data was generated, leading to matching
2443        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2444        matching string must start with a or b or c. The correct conclusion for
2445        this pattern is that a match can start with any character.
2448    Version 4.4 13-Aug-03
2449    ---------------------
2451     1. In UTF-8 mode, a character class containing characters with values between
2452        127 and 255 was not handled correctly if the compiled pattern was studied.
2453        In fixing this, I have also improved the studying algorithm for such
2454        classes (slightly).
2456     2. Three internal functions had redundant arguments passed to them. Removal
2457        might give a very teeny performance improvement.
2459     3. Documentation bug: the value of the capture_top field in a callout is *one
2460        more than* the number of the hightest numbered captured substring.
2462     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2463        in incorrectly linking with a previously installed version. They now link
2464        explicitly with libpcre.la.
2466     5. configure.in no longer needs to recognize Cygwin specially.
2468     6. A problem in pcre.in for Windows platforms is fixed.
2470     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2471        pcretest, it used to include the size of the study block as part of its
2472        output. Unfortunately, the structure contains a field that has a different
2473        size on different hardware architectures. This meant that the tests that
2474        showed this size failed. As the block is currently always of a fixed size,
2475        this information isn't actually particularly useful in pcretest output, so
2476        I have just removed it.
2478     8. Three pre-processor statements accidentally did not start in column 1.
2479        Sadly, there are *still* compilers around that complain, even though
2480        standard C has not required this for well over a decade. Sigh.
2482     9. In pcretest, the code for checking callouts passed small integers in the
2483        callout_data field, which is a void * field. However, some picky compilers
2484        complained about the casts involved for this on 64-bit systems. Now
2485        pcretest passes the address of the small integer instead, which should get
2486        rid of the warnings.
2488    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2489        both compile and run time, and gives an error if an invalid UTF-8 sequence
2490        is found. There is a option for disabling this check in cases where the
2491        string is known to be correct and/or the maximum performance is wanted.
2493    11. In response to a bug report, I changed one line in Makefile.in from
2495            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2496        to
2497            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2499        to look similar to other lines, but I have no way of telling whether this
2500        is the right thing to do, as I do not use Windows. No doubt I'll get told
2501        if it's wrong...
2504  Version 4.3 21-May-03  Version 4.3 21-May-03
2505  ---------------------  ---------------------

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