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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.01 06-Jan-10
5    ----------------------
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
12    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13        the pattern is reset in the first branch, pcre_compile() failed with
14        "internal error: code overflow at offset...". This happened only when
15        the reset was to the original external option setting. (An optimization
16        abstracts leading options settings into an external setting, which was the
17        cause of this.)
19    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21        assertion pattern did not match (meaning that the assertion was true), it
22        was incorrectly treated as false if the SKIP had been reached during the
23        matching. This also applied to assertions used as conditions.
25    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
26        assertion subpattern, including such a pattern used as a condition,
27        unpredictable results occurred, instead of the error return
30    5.  The C++ GlobalReplace function was not working like Perl for the special
31        situation when an empty string is matched. It now does the fancy magic
32        stuff that is necessary.
34    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
35        removed. (These were left over from very, very early versions of PCRE.)
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
40        (a) Change DEBUG to PCRE_DEBUG.
42        (b) In pcre_compile(), rename the member of the "branch_chain" structure
43            called "current" as "current_branch", to prevent a collision with the
44            Linux macro when compiled as a kernel module.
46        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
47            prevent a collision with the Linux macro when compiled as a kernel
48            module.
50    8.  In pcre_compile() there are some checks for integer overflows that used to
51        cast potentially large values to (double). This has been changed to that
52        when building, a check for int64_t is made, and if it is found, it is used
53        instead, thus avoiding the use of floating point arithmetic. (There is no
54        other use of FP in PCRE.) If int64_t is not found, the fallback is to
55        double.
57    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
58        2005 (difference between two addresses compared to an unsigned value).
60    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
61        custom one, because of the following reported problem in Windows:
63          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
64            under Win32.
65          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
66            therefore missing the function definition.
67          - The compiler thus generates a "C" signature for the test function.
68          - The linker fails to find the "C" function.
69          - PCRE fails to configure if asked to do so against libbz2.
71    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
72        messages were output:
74          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
75          rerunning libtoolize, to keep the correct libtool macros in-tree.
76          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
78        I have done both of these things.
80    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
81        most of the time, it *can* run out if it is given a pattern that contains a
82        runaway infinite recursion. I updated the discussion in the pcrestack man
83        page.
85    13. Now that we have gone to the x.xx style of version numbers, the minor
86        version may start with zero. Using 08 or 09 is a bad idea because users
87        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
88        interpreted as invalid octal numbers. I've updated the previous comment in
89        configure.ac, and also added a check that gives an error if 08 or 09 are
90        used.
92    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
93        causing partial matching to fail when the end of the subject matched \W
94        in a UTF-8 pattern where \W was quantified with a minimum of 3.
96    15. There were some discrepancies between the declarations in pcre_internal.h
97        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
98        their definitions. The declarations used "const uschar *" and the
99        definitions used USPTR. Even though USPTR is normally defined as "const
100        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
101        reported that: "This difference in casting confuses some C++ compilers, for
102        example, SunCC recognizes above declarations as different functions and
103        generates broken code for hbpcre." I have changed the declarations to use
104        USPTR.
106    16. GNU libtool is named differently on some systems. The autogen.sh script now
107        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
108        (FreeBSD).
110    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
111        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
112        comment: "Figure out how to create a longlong from a string: strtoll and
113        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
114        instance, but it only takes 2 args instead of 3!"
117    Version 8.00 19-Oct-09
118    ----------------------
120    1.  The table for translating pcre_compile() error codes into POSIX error codes
121        was out-of-date, and there was no check on the pcre_compile() error code
122        being within the table. This could lead to an OK return being given in
123        error.
125    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
126        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
127        in a Windows environment.
129    3.  The pcregrep --count option prints the count for each file even when it is
130        zero, as does GNU grep. However, pcregrep was also printing all files when
131        --files-with-matches was added. Now, when both options are given, it prints
132        counts only for those files that have at least one match. (GNU grep just
133        prints the file name in this circumstance, but including the count seems
134        more useful - otherwise, why use --count?) Also ensured that the
135        combination -clh just lists non-zero counts, with no names.
137    4.  The long form of the pcregrep -F option was incorrectly implemented as
138        --fixed_strings instead of --fixed-strings. This is an incompatible change,
139        but it seems right to fix it, and I didn't think it was worth preserving
140        the old behaviour.
142    5.  The command line items --regex=pattern and --regexp=pattern were not
143        recognized by pcregrep, which required --regex pattern or --regexp pattern
144        (with a space rather than an '='). The man page documented the '=' forms,
145        which are compatible with GNU grep; these now work.
147    6.  No libpcreposix.pc file was created for pkg-config; there was just
148        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
150    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
151        when UCP support is not needed, by modifying the Python script that
152        generates it from Unicode data files. This should not matter if the module
153        is correctly used as a library, but I received one complaint about 50K of
154        unwanted data. My guess is that the person linked everything into his
155        program rather than using a library. Anyway, it does no harm.
157    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
158        was a minimum greater than 1 for a wide character in a possessive
159        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
160        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
161        character. Chaos in the form of incorrect output or a compiling loop could
162        result.
164    9.  The restrictions on what a pattern can contain when partial matching is
165        requested for pcre_exec() have been removed. All patterns can now be
166        partially matched by this function. In addition, if there are at least two
167        slots in the offset vector, the offset of the earliest inspected character
168        for the match and the offset of the end of the subject are set in them when
169        PCRE_ERROR_PARTIAL is returned.
171    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
172        synonymous with PCRE_PARTIAL, for backwards compatibility, and
173        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
174        and may be more useful for multi-segment matching.
176    11. Partial matching with pcre_exec() is now more intuitive. A partial match
177        used to be given if ever the end of the subject was reached; now it is
178        given only if matching could not proceed because another character was
179        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
180        string "Z", which now yields "no match" instead of "partial match". In the
181        case of pcre_dfa_exec(), "no match" is given if every matching path for the
182        final character ended with (*FAIL).
184    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
185        if the pattern had a "must contain" character that was already found in the
186        earlier partial match, unless partial matching was again requested. For
187        example, with the pattern /dog.(body)?/, the "must contain" character is
188        "g". If the first part-match was for the string "dog", restarting with
189        "sbody" failed. This bug has been fixed.
191    13. The string returned by pcre_dfa_exec() after a partial match has been
192        changed so that it starts at the first inspected character rather than the
193        first character of the match. This makes a difference only if the pattern
194        starts with a lookbehind assertion or \b or \B (\K is not supported by
195        pcre_dfa_exec()). It's an incompatible change, but it makes the two
196        matching functions compatible, and I think it's the right thing to do.
198    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
199        so that the demonstration program is easily available in environments where
200        PCRE has not been installed from source.
202    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
203        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
204        library.
206    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
207        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
208        is not the first non-POSIX option to be added. Clearly some people find
209        these options useful.
211    17. If a caller to the POSIX matching function regexec() passes a non-zero
212        value for nmatch with a NULL value for pmatch, the value of
213        nmatch is forced to zero.
215    18. RunGrepTest did not have a test for the availability of the -u option of
216        the diff command, as RunTest does. It now checks in the same way as
217        RunTest, and also checks for the -b option.
219    19. If an odd number of negated classes containing just a single character
220        interposed, within parentheses, between a forward reference to a named
221        subpattern and the definition of the subpattern, compilation crashed with
222        an internal error, complaining that it could not find the referenced
223        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
224        [The bug was that it was starting one character too far in when skipping
225        over the character class, thus treating the ] as data rather than
226        terminating the class. This meant it could skip too much.]
228    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
229        /g option in pcretest when the pattern contains \K, which makes it possible
230        to have an empty string match not at the start, even when the pattern is
231        anchored. Updated pcretest and pcredemo to use this option.
233    21. If the maximum number of capturing subpatterns in a recursion was greater
234        than the maximum at the outer level, the higher number was returned, but
235        with unset values at the outer level. The correct (outer level) value is
236        now given.
238    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
239        PCRE did not set those parentheses (unlike Perl). I have now found a way to
240        make it do so. The string so far is captured, making this feature
241        compatible with Perl.
243    23. The tests have been re-organized, adding tests 11 and 12, to make it
244        possible to check the Perl 5.10 features against Perl 5.10.
246    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
247        pattern matches a fixed length string. PCRE did not allow this; now it
248        does. Neither allows recursion.
250    25. I finally figured out how to implement a request to provide the minimum
251        length of subject string that was needed in order to match a given pattern.
252        (It was back references and recursion that I had previously got hung up
253        on.) This code has now been added to pcre_study(); it finds a lower bound
254        to the length of subject needed. It is not necessarily the greatest lower
255        bound, but using it to avoid searching strings that are too short does give
256        some useful speed-ups. The value is available to calling programs via
257        pcre_fullinfo().
259    26. While implementing 25, I discovered to my embarrassment that pcretest had
260        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
261        study optimizations had never been tested with that matching function.
262        Oops. What is worse, even when it was passed study data, there was a bug in
263        pcre_dfa_exec() that meant it never actually used it. Double oops. There
264        were also very few tests of studied patterns with pcre_dfa_exec().
266    27. If (?| is used to create subpatterns with duplicate numbers, they are now
267        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
268        on the other side of the coin, they are no longer allowed to have different
269        names, because these cannot be distinguished in PCRE, and this has caused
270        confusion. (This is a difference from Perl.)
272    28. When duplicate subpattern names are present (necessarily with different
273        numbers, as required by 27 above), and a test is made by name in a
274        conditional pattern, either for a subpattern having been matched, or for
275        recursion in such a pattern, all the associated numbered subpatterns are
276        tested, and the overall condition is true if the condition is true for any
277        one of them. This is the way Perl works, and is also more like the way
278        testing by number works.
281    Version 7.9 11-Apr-09
282    ---------------------
284    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
285        (pcretest), all targets were linked against these libraries. This included
286        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
287        libraries. This caused unwanted dependencies to be created. This problem
288        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
289        pcretest is linked with readline.
291    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
292        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
293        moved outside it again, because FALSE and TRUE are already defined in AIX,
294        but BOOL is not.
296    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
297        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
299    4.  The pcregrep documentation said spaces were inserted as well as colons (or
300        hyphens) following file names and line numbers when outputting matching
301        lines. This is not true; no spaces are inserted. I have also clarified the
302        wording for the --colour (or --color) option.
304    5.  In pcregrep, when --colour was used with -o, the list of matching strings
305        was not coloured; this is different to GNU grep, so I have changed it to be
306        the same.
308    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
309        each matching line was coloured. Now it goes on to look for further matches
310        of any of the test patterns, which is the same behaviour as GNU grep.
312    7.  A pattern that could match an empty string could cause pcregrep to loop; it
313        doesn't make sense to accept an empty string match in pcregrep, so I have
314        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
315        seems to be how GNU grep behaves.
317    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
318        start or after a newline", because the conditional assertion was not being
319        correctly handled. The rule now is that both the assertion and what follows
320        in the first alternative must satisfy the test.
322    9.  If auto-callout was enabled in a pattern with a conditional group whose
323        condition was an assertion, PCRE could crash during matching, both with
324        pcre_exec() and pcre_dfa_exec().
326    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
327        used for matching.
329    11. Unicode property support in character classes was not working for
330        characters (bytes) greater than 127 when not in UTF-8 mode.
332    12. Added the -M command line option to pcretest.
334    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
336    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
338    16. Added comments and documentation about mis-use of no_arg in the C++
339        wrapper.
341    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
342        from Martin Jerabek that uses macro names for all relevant character and
343        string constants.
345    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
346        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
347        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
348        these, but not everybody uses configure.
350    19. A conditional group that had only one branch was not being correctly
351        recognized as an item that could match an empty string. This meant that an
352        enclosing group might also not be so recognized, causing infinite looping
353        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
354        with the subject "ab", where knowledge that the repeated group can match
355        nothing is needed in order to break the loop.
357    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
358        exec(), but without supplying a callout function, matching went wrong.
360    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
361        leak if the size of the offset vector was greater than 30. When the vector
362        is smaller, the saved offsets during recursion go onto a local stack
363        vector, but for larger vectors malloc() is used. It was failing to free
364        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
365        error, in fact).
367    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
368        heapframe that is used only when UTF-8 support is enabled. This caused no
369        problem, but was untidy.
371    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
372        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
373        included within another project.
375    24. Steven Van Ingelgem's patches to add more options to the CMake support,
376        slightly modified by me:
378          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
379              not building pcregrep.
381          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
382              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
384    25. Forward references, both numeric and by name, in patterns that made use of
385        duplicate group numbers, could behave incorrectly or give incorrect errors,
386        because when scanning forward to find the reference group, PCRE was not
387        taking into account the duplicate group numbers. A pattern such as
388        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
390    26. Changed a few more instances of "const unsigned char *" to USPTR, making
391        the feature of a custom pointer more persuasive (as requested by a user).
393    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
394        pcretest.c, inside #ifndefs, because it seems they are sometimes already
395        pre-defined.
397    28. Added support for (*UTF8) at the start of a pattern.
399    29. Arrange for flags added by the "release type" setting in CMake to be shown
400        in the configuration summary.
403    Version 7.8 05-Sep-08
404    ---------------------
406    1.  Replaced UCP searching code with optimized version as implemented for Ad
407        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
408        stage table and inline lookup instead of a function, giving speed ups of 2
409        to 5 times on some simple patterns that I tested. Permission was given to
410        distribute the MultiStage2.py script that generates the tables (it's not in
411        the tarball, but is in the Subversion repository).
413    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
414        scripts.
416    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
417        a group with a zero qualifier. The result of the study could be incorrect,
418        or the function might crash, depending on the pattern.
420    4.  Caseless matching was not working for non-ASCII characters in back
421        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
422        It now works when Unicode Property Support is available.
424    5.  In pcretest, an escape such as \x{de} in the data was always generating
425        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
426        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
427        truncation.
429    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
431    7.  Added two (int) casts to pcregrep when printing the difference of two
432        pointers, in case they are 64-bit values.
434    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
435        test 2 if it fails.
437    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
438        and a #define of that name to empty if it is not externally set. This is to
439        allow users of MSVC to set it if necessary.
441    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
442        the convenience functions in the pcre_get.c source file.
444    11. An option change at the start of a pattern that had top-level alternatives
445        could cause overwriting and/or a crash. This command provoked a crash in
446        some environments:
448          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
450        This potential security problem was recorded as CVE-2008-2371.
452    12. For a pattern where the match had to start at the beginning or immediately
453        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
454        pcre_dfa_exec() could read past the end of the passed subject if there was
455        no match. To help with detecting such bugs (e.g. with valgrind), I modified
456        pcretest so that it places the subject at the end of its malloc-ed buffer.
458    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
459        exec() might read past the end of the data buffer in UTF-8 mode.
461    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
462        the data contained the byte 0x85 as part of a UTF-8 character within its
463        first line. This applied both to normal and DFA matching.
465    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
466        /^[^d]*?$/8 failed to match "abc".
468    16. Added a missing copyright notice to pcrecpp_internal.h.
470    17. Make it more clear in the documentation that values returned from
471        pcre_exec() in ovector are byte offsets, not character counts.
473    18. Tidied a few places to stop certain compilers from issuing warnings.
475    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
476        supplied by Stefan Weber. I made a further small update for 7.8 because
477        there is a change of source arrangements: the pcre_searchfuncs.c module is
478        replaced by pcre_ucd.c.
481    Version 7.7 07-May-08
482    ---------------------
484    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
485        a string to a long long, pretend we don't even have a long long." This is
486        done by checking for the strtoq, strtoll, and _strtoi64 functions.
488    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
489        pre-7.6 versions, which defined a global no_arg variable instead of putting
490        it in the RE class. (See also #8 below.)
492    3.  Remove a line of dead code, identified by coverity and reported by Nuno
493        Lopes.
495    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
497        (1) The include/exclude patterns were being applied to the whole pathnames
498            of files, instead of just to the final components.
500        (2) If there was more than one level of directory, the subdirectories were
501            skipped unless they satisfied the include/exclude conditions. This is
502            inconsistent with GNU grep (and could even be seen as contrary to the
503            pcregrep specification - which I improved to make it absolutely clear).
504            The action now is always to scan all levels of directory, and just
505            apply the include/exclude patterns to regular files.
507    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
508        --exclude_dir in the tests to avoid scanning .svn directories.
510    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
511        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
512        doesn't support NULs in patterns.
514    7.  Added some missing "const"s to declarations of static tables in
515        pcre_compile.c and pcre_dfa_exec.c.
517    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
518        caused by fix #2  above. (Subsequently also a second patch to fix the
519        first patch. And a third patch - this was a messy problem.)
521    9.  Applied Craig's patch to remove the use of push_back().
523    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
524        matching function regexec().
526    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
527        which, however, unlike Perl's \g{...}, are subroutine calls, not back
528        references. PCRE supports relative numbers with this syntax (I don't think
529        Oniguruma does).
531    12. Previously, a group with a zero repeat such as (...){0} was completely
532        omitted from the compiled regex. However, this means that if the group
533        was called as a subroutine from elsewhere in the pattern, things went wrong
534        (an internal error was given). Such groups are now left in the compiled
535        pattern, with a new opcode that causes them to be skipped at execution
536        time.
538    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
539        to the way PCRE behaves:
541        (a) A lone ] character is dis-allowed (Perl treats it as data).
543        (b) A back reference to an unmatched subpattern matches an empty string
544            (Perl fails the current match path).
546        (c) A data ] in a character class must be notated as \] because if the
547            first data character in a class is ], it defines an empty class. (In
548            Perl it is not possible to have an empty class.) The empty class []
549            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
550            The negative empty class [^] matches any one character, independently
551            of the DOTALL setting.
553    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
554        non-existent subpattern following a character class starting with ']' and
555        containing () gave an internal compiling error instead of "reference to
556        non-existent subpattern". Fortunately, when the pattern did exist, the
557        compiled code was correct. (When scanning forwards to check for the
558        existencd of the subpattern, it was treating the data ']' as terminating
559        the class, so got the count wrong. When actually compiling, the reference
560        was subsequently set up correctly.)
562    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
563        it was being rejected as not supported by pcre_dfa_exec(), even though
564        other assertions are supported. I have made pcre_dfa_exec() support
565        (*FAIL).
567    16. The implementation of 13c above involved the invention of a new opcode,
568        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
569        cannot be changed at match time, I realized I could make a small
570        improvement to matching performance by compiling OP_ALLANY instead of
571        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
572        on the OP_ANY path.
574    17. Compiling pcretest on Windows with readline support failed without the
575        following two fixes: (1) Make the unistd.h include conditional on
576        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
578    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
579        ncurses library to be included for pcretest when ReadLine support is
580        requested, but also to allow for it to be overridden. This patch came from
581        Daniel Bergström.
583    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
584        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
585        any errors with the current Unicode tables. Thanks to Peter Kankowski for
586        spotting this.
589    Version 7.6 28-Jan-08
590    ---------------------
592    1.  A character class containing a very large number of characters with
593        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
594        overflow.
596    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
597        HAVE_LONG_LONG is not defined.
599    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
600        bring them up to date and include new features. This patch includes:
602        - Fixed PH's badly added libz and libbz2 support.
603        - Fixed a problem with static linking.
604        - Added pcredemo. [But later removed - see 7 below.]
605        - Fixed dftables problem and added an option.
606        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
607            HAVE_LONG_LONG.
608        - Added readline support for pcretest.
609        - Added an listing of the option settings after cmake has run.
611    4.  A user submitted a patch to Makefile that makes it easy to create
612        "pcre.dll" under mingw when using Configure/Make. I added stuff to
613        Makefile.am that cause it to include this special target, without
614        affecting anything else. Note that the same mingw target plus all
615        the other distribution libraries and programs are now supported
616        when configuring with CMake (see 6 below) instead of with
617        Configure/Make.
619    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
620        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
621        exported in the Windows port". It has not yet been confirmed that the patch
622        solves the problem, but it does no harm.
624    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
625        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
626        with CMake, and also correct the comment about stack recursion.
628    7.  Remove the automatic building of pcredemo from the ./configure system and
629        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
630        of a program that users should build themselves after PCRE is installed, so
631        building it automatically is not really right. What is more, it gave
632        trouble in some build environments.
634    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
637    Version 7.5 10-Jan-08
638    ---------------------
640    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
641        values in parens when parsing an RE using the C++ wrapper."
643    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
644        Characters greater than 255 were excluded from the class instead of being
645        included.
647    3.  The same bug as (2) above applied to negated POSIX classes such as
648        [:^space:].
650    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
651        defined or documented. It seems to have been a typo for PCRE_STATIC, so
652        I have changed it.
654    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
655        first named subpattern) and a construct such as (?&a) would reference the
656        first named subpattern whose name started with "a" (in other words, the
657        length check was missing). Both these problems are fixed. "Subpattern name
658        expected" is now given for (?&) (a zero-length name), and this patch also
659        makes it give the same error for \k'' (previously it complained that that
660        was a reference to a non-existent subpattern).
662    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
663        this is right because (?- can be followed by option settings as well as by
664        digits. I have, however, made the messages clearer.
666    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
667        than the number used in the conditional) now cause a compile-time error.
668        This is actually not compatible with Perl, which accepts such patterns, but
669        treats the conditional as always being FALSE (as PCRE used to), but it
670        seems to me that giving a diagnostic is better.
672    8.  Change "alphameric" to the more common word "alphanumeric" in comments
673        and messages.
675    9.  Fix two occurrences of "backslash" in comments that should have been
676        "backspace".
678    10. Remove two redundant lines of code that can never be obeyed (their function
679        was moved elsewhere).
681    11. The program that makes PCRE's Unicode character property table had a bug
682        which caused it to generate incorrect table entries for sequences of
683        characters that have the same character type, but are in different scripts.
684        It amalgamated them into a single range, with the script of the first of
685        them. In other words, some characters were in the wrong script. There were
686        thirteen such cases, affecting characters in the following ranges:
688          U+002b0 - U+002c1
689          U+0060c - U+0060d
690          U+0061e - U+00612
691          U+0064b - U+0065e
692          U+0074d - U+0076d
693          U+01800 - U+01805
694          U+01d00 - U+01d77
695          U+01d9b - U+01dbf
696          U+0200b - U+0200f
697          U+030fc - U+030fe
698          U+03260 - U+0327f
699          U+0fb46 - U+0fbb1
700          U+10450 - U+1049d
702    12. The -o option (show only the matching part of a line) for pcregrep was not
703        compatible with GNU grep in that, if there was more than one match in a
704        line, it showed only the first of them. It now behaves in the same way as
705        GNU grep.
707    13. If the -o and -v options were combined for pcregrep, it printed a blank
708        line for every non-matching line. GNU grep prints nothing, and pcregrep now
709        does the same. The return code can be used to tell if there were any
710        non-matching lines.
712    14. Added --file-offsets and --line-offsets to pcregrep.
714    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
715        infinitely looping recursion. The bug was that positive lookaheads were not
716        being skipped when checking for a possible empty match (negative lookaheads
717        and both kinds of lookbehind were skipped).
719    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
720        inclusion of <windows.h> to before rather than after the definition of
721        INVALID_FILE_ATTRIBUTES (patch from David Byron).
723    17. Specifying a possessive quantifier with a specific limit for a Unicode
724        character property caused pcre_compile() to compile bad code, which led at
725        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
726        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
727        caused the error; without that there was no problem.
729    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
731    19. Added --enable-pcretest-libreadline.
733    20. In pcrecpp.cc, the variable 'count' was incremented twice in
734        RE::GlobalReplace(). As a result, the number of replacements returned was
735        double what it should be. I removed one of the increments, but Craig sent a
736        later patch that removed the other one (the right fix) and added unit tests
737        that check the return values (which was not done before).
739    21. Several CMake things:
741        (1) Arranged that, when cmake is used on Unix, the libraries end up with
742            the names libpcre and libpcreposix, not just pcre and pcreposix.
744        (2) The above change means that pcretest and pcregrep are now correctly
745            linked with the newly-built libraries, not previously installed ones.
749    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
750        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
751        UTF-8 newline character). The key issue is that the pattern starts .*;
752        this means that the match must be either at the beginning, or after a
753        newline. The bug was in the code for advancing after a failed match and
754        checking that the new position followed a newline. It was not taking
755        account of UTF-8 characters correctly.
757    23. PCRE was behaving differently from Perl in the way it recognized POSIX
758        character classes. PCRE was not treating the sequence [:...:] as a
759        character class unless the ... were all letters. Perl, however, seems to
760        allow any characters between [: and :], though of course it rejects as
761        unknown any "names" that contain non-letters, because all the known class
762        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
763        for example, whereas PCRE did not - it did not recognize a POSIX character
764        class. This seemed a bit dangerous, so the code has been changed to be
765        closer to Perl. The behaviour is not identical to Perl, because PCRE will
766        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
767        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
768        Perl does, and where it didn't before.
770    24. Rewrite so as to remove the single use of %n from pcregrep because in some
771        Windows environments %n is disabled by default.
774    Version 7.4 21-Sep-07
775    ---------------------
777    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
778        means that a class such as [\s] counted as "explicit reference to CR or
779        LF". That isn't really right - the whole point of the change was to try to
780        help when there was an actual mention of one of the two characters. So now
781        the change happens only if \r or \n (or a literal CR or LF) character is
782        encountered.
784    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
785        of both had grown to the point where there were only 3 bits left.
786        Fortunately, there was spare space in the data structure, and so I have
787        moved the internal flags into a new 16-bit field to free up more option
788        bits.
790    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
791        but did not set the internal JCHANGED flag - either of these is enough to
792        control the way the "get" function works - but the PCRE_INFO_JCHANGED
793        facility is supposed to tell if (?J) was ever used, so now (?J) at the
794        start sets both bits.
796    4.  Added options (at build time, compile time, exec time) to change \R from
797        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
799    5.  doc/pcresyntax.html was missing from the distribution.
801    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
802        compatibility, even though it is no longer used.
804    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
805        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
806        windows.h file is present (where different names are used). [This was
807        reversed later after testing - see 16 below.]
809    8.  Changed all #include <config.h> to #include "config.h". There were also
810        some further <pcre.h> cases that I changed to "pcre.h".
812    9.  When pcregrep was used with the --colour option, it missed the line ending
813        sequence off the lines that it output.
815    10. It was pointed out to me that arrays of string pointers cause lots of
816        relocations when a shared library is dynamically loaded. A technique of
817        using a single long string with a table of offsets can drastically reduce
818        these. I have refactored PCRE in four places to do this. The result is
819        dramatic:
821          Originally:                          290
822          After changing UCP table:            187
823          After changing error message table:   43
824          After changing table of "verbs"       36
825          After changing table of Posix names   22
827        Thanks to the folks working on Gregex for glib for this insight.
829    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
830        unicode-properties was also set.
832    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
834    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
835        checked only for CRLF.
837    14. Added casts to pcretest.c to avoid compiler warnings.
839    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
841    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
842        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
843        entirely. This removes changes made in 7 above.
845    17. The CMake files have been updated, and there is now more information about
846        building with CMake in the NON-UNIX-USE document.
849    Version 7.3 28-Aug-07
850    ---------------------
852     1. In the rejigging of the build system that eventually resulted in 7.1, the
853        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
854        brackets there is not right, since it causes compilers to look for an
855        installed pcre.h, not the version that is in the source that is being
856        compiled (which of course may be different). I have changed it back to:
858          #include "pcre.h"
860        I have a vague recollection that the change was concerned with compiling in
861        different directories, but in the new build system, that is taken care of
862        by the VPATH setting the Makefile.
864     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
865        when the subject happened to end in the byte 0x85 (e.g. if the last
866        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
867        characters but of course it shouldn't be taken as a newline when it is part
868        of another character. The bug was that, for an unlimited repeat of . in
869        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
870        characters when looking for a newline.
872     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
874     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
875        in debug output.
877     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
878        long printing in the pcrecpp unittest when running under MinGW.
880     6. ESC_K was left out of the EBCDIC table.
882     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
883        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
884        limit also applies to "virtual nesting" when a pattern is recursive, and in
885        this case 1000 isn't so big. I have been able to remove this limit at the
886        expense of backing off one optimization in certain circumstances. Normally,
887        when pcre_exec() would call its internal match() function recursively and
888        immediately return the result unconditionally, it uses a "tail recursion"
889        feature to save stack. However, when a subpattern that can match an empty
890        string has an unlimited repetition quantifier, it no longer makes this
891        optimization. That gives it a stack frame in which to save the data for
892        checking that an empty string has been matched. Previously this was taken
893        from the 1000-entry workspace that had been reserved. So now there is no
894        explicit limit, but more stack is used.
896     8. Applied Daniel's patches to solve problems with the import/export magic
897        syntax that is required for Windows, and which was going wrong for the
898        pcreposix and pcrecpp parts of the library. These were overlooked when this
899        problem was solved for the main library.
901     9. There were some crude static tests to avoid integer overflow when computing
902        the size of patterns that contain repeated groups with explicit upper
903        limits. As the maximum quantifier is 65535, the maximum group length was
904        set at 30,000 so that the product of these two numbers did not overflow a
905        32-bit integer. However, it turns out that people want to use groups that
906        are longer than 30,000 bytes (though not repeat them that many times).
907        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
908        made it possible to implement the integer overflow checks in a much more
909        dynamic way, which I have now done. The artificial limitation on group
910        length has been removed - we now have only the limit on the total length of
911        the compiled pattern, which depends on the LINK_SIZE setting.
913    10. Fixed a bug in the documentation for get/copy named substring when
914        duplicate names are permitted. If none of the named substrings are set, the
915        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
916        empty string.
918    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
919        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
920        because the ] is interpreted as the first data character and the
921        terminating ] is not found. PCRE has been made compatible with Perl in this
922        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
923        cause memory overwriting.
925    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
926        string has been matched (to stop an infinite loop). It was not recognizing
927        a conditional subpattern that could match an empty string if that
928        subpattern was within another subpattern. For example, it looped when
929        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
930        condition was not nested. This bug has been fixed.
932    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
933        past the start of the subject in the presence of bytes with the top bit
934        set, for example "\x8aBCD".
936    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
937        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
939    14. Optimized (?!) to (*FAIL).
941    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
942        This restricts code points to be within the range 0 to 0x10FFFF, excluding
943        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
944        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
945        does: it's just the validity check that is more restrictive.
947    16. Inserted checks for integer overflows during escape sequence (backslash)
948        processing, and also fixed erroneous offset values for syntax errors during
949        backslash processing.
951    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
952        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
954    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
955        caused an overrun.
957    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
958        something other than just ASCII characters) inside a group that had an
959        unlimited repeat caused a loop at compile time (while checking to see
960        whether the group could match an empty string).
962    20. Debugging a pattern containing \p or \P could cause a crash. For example,
963        [\P{Any}] did so. (Error in the code for printing property names.)
965    21. An orphan \E inside a character class could cause a crash.
967    22. A repeated capturing bracket such as (A)? could cause a wild memory
968        reference during compilation.
970    23. There are several functions in pcre_compile() that scan along a compiled
971        expression for various reasons (e.g. to see if it's fixed length for look
972        behind). There were bugs in these functions when a repeated \p or \P was
973        present in the pattern. These operators have additional parameters compared
974        with \d, etc, and these were not being taken into account when moving along
975        the compiled data. Specifically:
977        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
978            length.
980        (b) An item such as \pL+ within a repeated group could cause crashes or
981            loops.
983        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
984            "reference to non-existent subpattern" error.
986        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
988    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
989        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
991    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
993    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
994        character were causing crashes (broken optimization).
996    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
997        \p or \P) caused a compile-time loop.
999    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1000        break. For example, the unstudied pattern [\r\n]A does not match the string
1001        "\r\nA" because change 7.0/46 below moves the current point on by two
1002        characters after failing to match at the start. However, the pattern \nA
1003        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1004        the same is true. There doesn't seem any very clean way out of this, but
1005        what I have chosen to do makes the common cases work: PCRE now takes note
1006        of whether there can be an explicit match for \r or \n anywhere in the
1007        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1008        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1009        pattern has explicit CR or LF references.
1011    29. Added (*CR) etc for changing newline setting at start of pattern.
1014    Version 7.2 19-Jun-07
1015    ---------------------
1017     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1018        which is apparently normally available under Windows.
1020     2. Re-jig the pcregrep tests with different newline settings in an attempt
1021        to make them independent of the local environment's newline setting.
1023     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1025     4. Some of the "internals" tests were previously cut out when the link size
1026        was not 2, because the output contained actual offsets. The recent new
1027        "Z" feature of pcretest means that these can be cut out, making the tests
1028        usable with all link sizes.
1030     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1031        stack recursion. This gives a massive performance boost under BSD, but just
1032        a small improvement under Linux. However, it saves one field in the frame
1033        in all cases.
1035     6. Added more features from the forthcoming Perl 5.10:
1037        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1038            recursion call. It refers to the nth most recently opened parentheses.
1040        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1041            to be opened parentheses.
1043        (c) Conditions that refer to capturing parentheses can be specified
1044            relatively, for example, (?(-2)... or (?(+3)...
1046        (d) \K resets the start of the current match so that everything before
1047            is not part of it.
1049        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1051        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1052            reference syntax.
1054        (g) (?| introduces a group in which the numbering of parentheses in each
1055            alternative starts with the same number.
1057        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1059     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1062     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1063        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1064        for detecting groups that can match an empty string.
1066     9. A pattern with a very large number of alternatives (more than several
1067        hundred) was running out of internal workspace during the pre-compile
1068        phase, where pcre_compile() figures out how much memory will be needed. A
1069        bit of new cunning has reduced the workspace needed for groups with
1070        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1071        workspace instead of running out of the 4096 that are available.
1073    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1075    11. Applied patch from Google to remove an optimization that didn't quite work.
1076        The report of the bug said:
1078          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1079          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1080          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1082    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1083        it matched the wrong number of bytes.
1086    Version 7.1 24-Apr-07
1087    ---------------------
1089     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1090        that is more "standard", making use of automake and other Autotools. There
1091        is some re-arrangement of the files and adjustment of comments consequent
1092        on this.
1094     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1095        for recursive directory scanning broke on some systems because the files
1096        are not scanned in any specific order and on different systems the order
1097        was different. A call to "sort" has been inserted into RunGrepTest for the
1098        approprate test as a short-term fix. In the longer term there may be an
1099        alternative.
1101     3. I had an email from Eric Raymond about problems translating some of PCRE's
1102        man pages to HTML (despite the fact that I distribute HTML pages, some
1103        people do their own conversions for various reasons). The problems
1104        concerned the use of low-level troff macros .br and .in. I have therefore
1105        removed all such uses from the man pages (some were redundant, some could
1106        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1107        HTML has been updated to handle .nf/.fi and to complain if it encounters
1108        .br or .in.
1110     4. Updated comments in configure.ac that get placed in config.h.in and also
1111        arranged for config.h to be included in the distribution, with the name
1112        config.h.generic, for the benefit of those who have to compile without
1113        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1115     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1116        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1117        makevp.bat for the current PCRE, using the additional files
1118        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1120     6. A Windows user reported a minor discrepancy with test 2, which turned out
1121        to be caused by a trailing space on an input line that had got lost in his
1122        copy. The trailing space was an accident, so I've just removed it.
1124     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1125        that is needed.
1127     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1128        as "const" (a) because they are and (b) because it helps the PHP
1129        maintainers who have recently made a script to detect big data structures
1130        in the php code that should be moved to the .rodata section. I remembered
1131        to update Builducptable as well, so it won't revert if ucptable.h is ever
1132        re-created.
1134     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1135        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1136        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1137        support is not required. This saves 1.5-2K of code, which is important in
1138        some applications.
1140        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1141        so as not to refer to the tables, even though these functions will never be
1142        called when UTF-8 support is disabled. Otherwise there are problems with a
1143        shared library.
1145    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1147        (a) It was defining its arguments as char * instead of void *.
1149        (b) It was assuming that all moves were upwards in memory; this was true
1150            a long time ago when I wrote it, but is no longer the case.
1152        The emulated memove() is provided for those environments that have neither
1153        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1154        is clearly not the case, as these two bugs were recently reported.
1156    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1157        and Detrail to create the HTML documentation, the .txt form of the man
1158        pages, and it removes trailing spaces from listed files. It also creates
1159        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1160        case, it wraps all the #defines with #ifndefs. This script should be run
1161        before "make dist".
1163    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1164        with Unicode property support.
1166        (a) For a maximizing quantifier, if the two different cases of the
1167            character were of different lengths in their UTF-8 codings (there are
1168            some cases like this - I found 11), and the matching function had to
1169            back up over a mixture of the two cases, it incorrectly assumed they
1170            were both the same length.
1172        (b) When PCRE was configured to use the heap rather than the stack for
1173            recursion during matching, it was not correctly preserving the data for
1174            the other case of a UTF-8 character when checking ahead for a match
1175            while processing a minimizing repeat. If the check also involved
1176            matching a wide character, but failed, corruption could cause an
1177            erroneous result when trying to check for a repeat of the original
1178            character.
1180    13. Some tidying changes to the testing mechanism:
1182        (a) The RunTest script now detects the internal link size and whether there
1183            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1184            values substituted by "configure". (The RunGrepTest script already did
1185            this for UTF-8.) The configure.ac script no longer substitutes the
1186            relevant variables.
1188        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1189            with length and offset values. This means that the output is different
1190            for different internal link sizes. Test 2 is skipped for link sizes
1191            other than 2 because of this, bypassing the problem. Unfortunately,
1192            there was also a test in test 3 (the locale tests) that used /B and
1193            failed for link sizes other than 2. Rather than cut the whole test out,
1194            I have added a new /Z option to pcretest that replaces the length and
1195            offset values with spaces. This is now used to make test 3 independent
1196            of link size. (Test 2 will be tidied up later.)
1198    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1199        segmentation fault instead of returning the appropriate error message.
1201    15. In multiline mode when the newline sequence was set to "any", the pattern
1202        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1203        This doesn't seem right; it now treats the CRLF combination as the line
1204        ending, and so does not match in that case. It's only a pattern such as ^$
1205        that would hit this one: something like ^ABC$ would have failed after \r
1206        and then tried again after \r\n.
1208    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1209        in an attempt to make files that differ only in their line terminators
1210        compare equal. This works on Linux.
1212    17. Under certain error circumstances pcregrep might try to free random memory
1213        as it exited. This is now fixed, thanks to valgrind.
1215    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1216        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1217        was because its rules for how to advance for /g after matching an empty
1218        string at the end of a line did not allow for this case. They now check for
1219        it specially.
1221    20. pcretest is supposed to handle patterns and data of any length, by
1222        extending its buffers when necessary. It was getting this wrong when the
1223        buffer for a data line had to be extended.
1225    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1226        CRLF as a newline sequence.
1228    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1229        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1230        I have nevertheless tidied it up.
1232    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1234    24. Added a man page for pcre-config.
1237    Version 7.0 19-Dec-06
1238    ---------------------
1240     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1241        moving to gcc 4.1.1.
1243     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1244        sys/time.h, which is documented as needed for this function. It doesn't
1245        seem to matter on Linux, but it showed up on some releases of OS X.
1247     3. It seems that there are systems where bytes whose values are greater than
1248        127 match isprint() in the "C" locale. The "C" locale should be the
1249        default when a C program starts up. In most systems, only ASCII printing
1250        characters match isprint(). This difference caused the output from pcretest
1251        to vary, making some of the tests fail. I have changed pcretest so that:
1253        (a) When it is outputting text in the compiled version of a pattern, bytes
1254            other than 32-126 are always shown as hex escapes.
1256        (b) When it is outputting text that is a matched part of a subject string,
1257            it does the same, unless a different locale has been set for the match
1258            (using the /L modifier). In this case, it uses isprint() to decide.
1260     4. Fixed a major bug that caused incorrect computation of the amount of memory
1261        required for a compiled pattern when options that changed within the
1262        pattern affected the logic of the preliminary scan that determines the
1263        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1264        that the computed length was too small. The symptoms of this bug were
1265        either the PCRE error "internal error: code overflow" from pcre_compile(),
1266        or a glibc crash with a message such as "pcretest: free(): invalid next
1267        size (fast)". Examples of patterns that provoked this bug (shown in
1268        pcretest format) are:
1270          /(?-x: )/x
1271          /(?x)(?-x: \s*#\s*)/
1272          /((?i)[\x{c0}])/8
1273          /(?i:[\x{c0}])/8
1275        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1276        is now done differently.
1278     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1279        wrapper classes; (b) implement a new function in the C++ scanner that is
1280        more efficient than the old way of doing things because it avoids levels of
1281        recursion in the regex matching; (c) add a paragraph to the documentation
1282        for the FullMatch() function.
1284     6. The escape sequence \n was being treated as whatever was defined as
1285        "newline". Not only was this contrary to the documentation, which states
1286        that \n is character 10 (hex 0A), but it also went horribly wrong when
1287        "newline" was defined as CRLF. This has been fixed.
1289     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1290        was being set to -1 for the "end of line" case (supposedly a value that no
1291        character can have). Though this value is never used (the check for end of
1292        line is "zero bytes in current character"), it caused compiler complaints.
1293        I've changed it to 0xffffffff.
1295     8. In pcre_version.c, the version string was being built by a sequence of
1296        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1297        string (as it is for production releases) called a macro with an empty
1298        argument. The C standard says the result of this is undefined. The gcc
1299        compiler treats it as an empty string (which was what was wanted) but it is
1300        reported that Visual C gives an error. The source has been hacked around to
1301        avoid this problem.
1303     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1304        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1305        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1306        of them did).
1308    10. Originally, pcretest opened its input and output without "b"; then I was
1309        told that "b" was needed in some environments, so it was added for release
1310        5.0 to both the input and output. (It makes no difference on Unix-like
1311        systems.) Later I was told that it is wrong for the input on Windows. I've
1312        now abstracted the modes into two macros, to make it easier to fiddle with
1313        them, and removed "b" from the input mode under Windows.
1315    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1317    12. Added -help and --help to pcretest as an official way of being reminded
1318        of the options.
1320    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1321        and pcrecpp.cc because they annoy compilers at high warning levels.
1323    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1325    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1326        scripts are not C programs :-) and which was not noticed because it works
1327        on Linux.
1329    16. pcretest is supposed to handle any length of pattern and data line (as one
1330        line or as a continued sequence of lines) by extending its input buffer if
1331        necessary. This feature was broken for very long pattern lines, leading to
1332        a string of junk being passed to pcre_compile() if the pattern was longer
1333        than about 50K.
1335    17. I have done a major re-factoring of the way pcre_compile() computes the
1336        amount of memory needed for a compiled pattern. Previously, there was code
1337        that made a preliminary scan of the pattern in order to do this. That was
1338        OK when PCRE was new, but as the facilities have expanded, it has become
1339        harder and harder to keep it in step with the real compile phase, and there
1340        have been a number of bugs (see for example, 4 above). I have now found a
1341        cunning way of running the real compile function in a "fake" mode that
1342        enables it to compute how much memory it would need, while actually only
1343        ever using a few hundred bytes of working memory and without too many
1344        tests of the mode. This should make future maintenance and development
1345        easier. A side effect of this work is that the limit of 200 on the nesting
1346        depth of parentheses has been removed (though this was never a serious
1347        limitation, I suspect). However, there is a downside: pcre_compile() now
1348        runs more slowly than before (30% or more, depending on the pattern). I
1349        hope this isn't a big issue. There is no effect on runtime performance.
1351    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1352        newline (only possible for the last line of a file) and it was a
1353        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1355    19. Added additional timing features to pcretest. (1) The -tm option now times
1356        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1357        separate command line item, by a number that specifies the number of
1358        repeats to use when timing. The default is 50000; this gives better
1359        precision, but takes uncomfortably long for very large patterns.
1361    20. Extended pcre_study() to be more clever in cases where a branch of a
1362        subpattern has no definite first character. For example, (a*|b*)[cd] would
1363        previously give no result from pcre_study(). Now it recognizes that the
1364        first character must be a, b, c, or d.
1366    21. There was an incorrect error "recursive call could loop indefinitely" if
1367        a subpattern (or the entire pattern) that was being tested for matching an
1368        empty string contained only one non-empty item after a nested subpattern.
1369        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1370        incorrectly, because the \d was being skipped in the check.
1372    22. The pcretest program now has a new pattern option /B and a command line
1373        option -b, which is equivalent to adding /B to every pattern. This causes
1374        it to show the compiled bytecode, without the additional information that
1375        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1376        is the same as /B/I).
1378    23. A new optimization is now able automatically to treat some sequences such
1379        as a*b as a*+b. More specifically, if something simple (such as a character
1380        or a simple class like \d) has an unlimited quantifier, and is followed by
1381        something that cannot possibly match the quantified thing, the quantifier
1382        is automatically "possessified".
1384    24. A recursive reference to a subpattern whose number was greater than 39
1385        went wrong under certain circumstances in UTF-8 mode. This bug could also
1386        have affected the operation of pcre_study().
1388    25. Realized that a little bit of performance could be had by replacing
1389        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1391    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1393    27. Possessive quantifiers such as a++ were previously implemented by turning
1394        them into atomic groups such as ($>a+). Now they have their own opcodes,
1395        which improves performance. This includes the automatically created ones
1396        from 23 above.
1398    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1399        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1400        the first matched character to be a colon. This applied both to named and
1401        numbered groups.
1403    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1405    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1406        building PCRE on Windows easier, so I have included it in the distribution.
1408    31. There is now a check in pcretest against a ridiculously large number being
1409        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1410        loop, the loop is abandoned.
1412    32. Forward references to subpatterns in conditions such as (?(2)...) where
1413        subpattern 2 is defined later cause pcre_compile() to search forwards in
1414        the pattern for the relevant set of parentheses. This search went wrong
1415        when there were unescaped parentheses in a character class, parentheses
1416        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1418    33. "Subroutine" calls and backreferences were previously restricted to
1419        referencing subpatterns earlier in the regex. This restriction has now
1420        been removed.
1422    34. Added a number of extra features that are going to be in Perl 5.10. On the
1423        whole, these are just syntactic alternatives for features that PCRE had
1424        previously implemented using the Python syntax or my own invention. The
1425        other formats are all retained for compatibility.
1427        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1428            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1429            also .NET compatible.
1431        (b) A recursion or subroutine call to a named group can now be defined as
1432            (?&name) as well as (?P>name).
1434        (c) A backreference to a named group can now be defined as \k<name> or
1435            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1436            5.10, are also .NET compatible.
1438        (d) A conditional reference to a named group can now use the syntax
1439            (?(<name>) or (?('name') as well as (?(name).
1441        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1442            groups (named and numbered) that are never evaluated inline, but can be
1443            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1444            is always false. There may be only one alternative in such a group.
1446        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1447            as the simple (?(R). The condition is true only if the most recent
1448            recursion is that of the given number or name. It does not search out
1449            through the entire recursion stack.
1451        (g) The escape \gN or \g{N} has been added, where N is a positive or
1452            negative number, specifying an absolute or relative reference.
1454    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1455        some "unreachable code" warnings.
1457    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1458        things, this adds five new scripts.
1460    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1461        There were also incompatibilities regarding the handling of \Q..\E inside
1462        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1463        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1465    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1466        matches an empty string, and forcibly breaks the loop. There were bugs in
1467        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1468        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1469        separate and independent bugs (that affected different cases) have been
1470        fixed.
1472    39. Refactored the code to abolish the use of different opcodes for small
1473        capturing bracket numbers. This is a tidy that I avoided doing when I
1474        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1475        The new approach is not only tidier, it makes it possible to reduce the
1476        memory needed to fix the previous bug (38).
1478    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1479        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1480        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1481        mode.
1483    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1484        report.
1486    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1487        copy construction and assignment in the C++ wrapper.
1489    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1490        couple of bugs that could have given wrong results in the "--newline=crlf"
1491        case.
1493    44. Added a number of casts and did some reorganization of signed/unsigned int
1494        variables following suggestions from Dair Grant. Also renamed the variable
1495        "this" as "item" because it is a C++ keyword.
1497    45. Arranged for dftables to add
1499          #include "pcre_internal.h"
1501        to pcre_chartables.c because without it, gcc 4.x may remove the array
1502        definition from the final binary if PCRE is built into a static library and
1503        dead code stripping is activated.
1505    46. For an unanchored pattern, if a match attempt fails at the start of a
1506        newline sequence, and the newline setting is CRLF or ANY, and the next two
1507        characters are CRLF, advance by two characters instead of one.
1510    Version 6.7 04-Jul-06
1511    ---------------------
1513     1. In order to handle tests when input lines are enormously long, pcretest has
1514        been re-factored so that it automatically extends its buffers when
1515        necessary. The code is crude, but this _is_ just a test program. The
1516        default size has been increased from 32K to 50K.
1518     2. The code in pcre_study() was using the value of the re argument before
1519        testing it for NULL. (Of course, in any sensible call of the function, it
1520        won't be NULL.)
1522     3. The memmove() emulation function in pcre_internal.h, which is used on
1523        systems that lack both memmove() and bcopy() - that is, hardly ever -
1524        was missing a "static" storage class specifier.
1526     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1527        containing an extended class (one that cannot be represented by a bitmap
1528        because it contains high-valued characters or Unicode property items, e.g.
1529        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1530        pattern, but PCRE should not loop if you do not (it no longer does).
1531        [Detail: two cases were found: (a) a repeated subpattern containing an
1532        extended class; (b) a recursive reference to a subpattern that followed a
1533        previous extended class. It wasn't skipping over the extended class
1534        correctly when UTF-8 mode was not set.]
1536     5. A negated single-character class was not being recognized as fixed-length
1537        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1538        compile error "lookbehind assertion is not fixed length".
1540     6. The RunPerlTest auxiliary script was showing an unexpected difference
1541        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1542        write a Perl script that can interpret lines of an input file either as
1543        byte characters or as UTF-8, which is what "perltest" was being required to
1544        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1545        can't do is switch easily at run time between having the "use utf8;" pragma
1546        or not. In the end, I fudged it by using the RunPerlTest script to insert
1547        "use utf8;" explicitly for the UTF-8 tests.
1549     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1550        the end of the subject string, contrary to the documentation and to what
1551        Perl does. This was true of both matching functions. Now it matches only at
1552        the start of the subject and immediately after *internal* newlines.
1554     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1555        a pointer to an int instead of a pointer to an unsigned long int. This
1556        caused problems on 64-bit systems.
1558     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1559        instance of the 'standard' template library not being so standard".
1561    10. There was no check on the number of named subpatterns nor the maximum
1562        length of a subpattern name. The product of these values is used to compute
1563        the size of the memory block for a compiled pattern. By supplying a very
1564        long subpattern name and a large number of named subpatterns, the size
1565        computation could be caused to overflow. This is now prevented by limiting
1566        the length of names to 32 characters, and the number of named subpatterns
1567        to 10,000.
1569    11. Subpatterns that are repeated with specific counts have to be replicated in
1570        the compiled pattern. The size of memory for this was computed from the
1571        length of the subpattern and the repeat count. The latter is limited to
1572        65535, but there was no limit on the former, meaning that integer overflow
1573        could in principle occur. The compiled length of a repeated subpattern is
1574        now limited to 30,000 bytes in order to prevent this.
1576    12. Added the optional facility to have named substrings with the same name.
1578    13. Added the ability to use a named substring as a condition, using the
1579        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1580        are numbers (not recommended). Forward references are permitted.
1582    14. Added forward references in named backreferences (if you see what I mean).
1584    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1585        pattern could run off the end of the subject. For example, the pattern
1586        "(?s)(.{1,5})"8 did this with the subject "ab".
1588    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1589        PCRE_CASELESS was set when matching characters that were quantified with ?
1590        or *.
1592    17. A character class other than a single negated character that had a minimum
1593        but no maximum quantifier - for example [ab]{6,} - was not handled
1594        correctly by pce_dfa_exec(). It would match only one character.
1596    18. A valid (though odd) pattern that looked like a POSIX character
1597        class but used an invalid character after [ (for example [[,abc,]]) caused
1598        pcre_compile() to give the error "Failed: internal error: code overflow" or
1599        in some cases to crash with a glibc free() error. This could even happen if
1600        the pattern terminated after [[ but there just happened to be a sequence of
1601        letters, a binary zero, and a closing ] in the memory that followed.
1603    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1604        over the years. Originally (before any Unicode support), just the bottom 8
1605        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1606        output from "man perlunicode" includes this:
1608          The regular expression compiler produces polymorphic opcodes.  That
1609          is, the pattern adapts to the data and automatically switches to
1610          the Unicode character scheme when presented with Unicode data--or
1611          instead uses a traditional byte scheme when presented with byte
1612          data.
1614        Sadly, a wide octal escape does not cause a switch, and in a string with
1615        no other multibyte characters, these octal escapes are treated as before.
1616        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1617        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1618        Unicode string.
1620        I have not perpetrated such confusion in PCRE. Up till now, it took just
1621        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1622        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1623        translate to the appropriate multibyte character.
1625    29. Applied some refactoring to reduce the number of warnings from Microsoft
1626        and Borland compilers. This has included removing the fudge introduced
1627        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1628        a warning about an unused variable.
1630    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1631        characters since release 4.0, because Perl (from release 5.004) does not.
1632        [Or at least, is documented not to: some releases seem to be in conflict
1633        with the documentation.] However, when a pattern was studied with
1634        pcre_study() and all its branches started with \s, PCRE still included VT
1635        as a possible starting character. Of course, this did no harm; it just
1636        caused an unnecessary match attempt.
1638    22. Removed a now-redundant internal flag bit that recorded the fact that case
1639        dependency changed within the pattern. This was once needed for "required
1640        byte" processing, but is no longer used. This recovers a now-scarce options
1641        bit. Also moved the least significant internal flag bit to the most-
1642        significant bit of the word, which was not previously used (hangover from
1643        the days when it was an int rather than a uint) to free up another bit for
1644        the future.
1646    23. Added support for CRLF line endings as well as CR and LF. As well as the
1647        default being selectable at build time, it can now be changed at runtime
1648        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1649        specify that it is scanning data with non-default line endings.
1651    24. Changed the definition of CXXLINK to make it agree with the definition of
1652        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1654    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1655        recursions. This makes a big different to stack usage for some patterns.
1657    26. If a subpattern containing a named recursion or subroutine reference such
1658        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1659        the space required for the compiled pattern went wrong and gave too small a
1660        value. Depending on the environment, this could lead to "Failed: internal
1661        error: code overflow at offset 49" or "glibc detected double free or
1662        corruption" errors.
1664    27. Applied patches from Google (a) to support the new newline modes and (b) to
1665        advance over multibyte UTF-8 characters in GlobalReplace.
1667    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1668        difference for some implementation of PCRE in some Windows version.
1670    29. Added some extra testing facilities to pcretest:
1672        \q<number>   in a data line sets the "match limit" value
1673        \Q<number>   in a data line sets the "match recursion limt" value
1674        -S <number>  sets the stack size, where <number> is in megabytes
1676        The -S option isn't available for Windows.
1679    Version 6.6 06-Feb-06
1680    ---------------------
1682     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1683        in pcreposix.h. I have copied the definition from pcre.h.
1685     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1686        because pcre.h is no longer a built file.
1688     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1689        not normally included in the compiled code.
1692    Version 6.5 01-Feb-06
1693    ---------------------
1695     1. When using the partial match feature with pcre_dfa_exec(), it was not
1696        anchoring the second and subsequent partial matches at the new starting
1697        point. This could lead to incorrect results. For example, with the pattern
1698        /1234/, partially matching against "123" and then "a4" gave a match.
1700     2. Changes to pcregrep:
1702        (a) All non-match returns from pcre_exec() were being treated as failures
1703            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1704            error message is output. Some extra information is given for the
1705            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1706            probably the only errors that are likely to be caused by users (by
1707            specifying a regex that has nested indefinite repeats, for instance).
1708            If there are more than 20 of these errors, pcregrep is abandoned.
1710        (b) A binary zero was treated as data while matching, but terminated the
1711            output line if it was written out. This has been fixed: binary zeroes
1712            are now no different to any other data bytes.
1714        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1715            used to set a locale for matching. The --locale=xxxx long option has
1716            been added (no short equivalent) to specify a locale explicitly on the
1717            pcregrep command, overriding the environment variables.
1719        (d) When -B was used with -n, some line numbers in the output were one less
1720            than they should have been.
1722        (e) Added the -o (--only-matching) option.
1724        (f) If -A or -C was used with -c (count only), some lines of context were
1725            accidentally printed for the final match.
1727        (g) Added the -H (--with-filename) option.
1729        (h) The combination of options -rh failed to suppress file names for files
1730            that were found from directory arguments.
1732        (i) Added the -D (--devices) and -d (--directories) options.
1734        (j) Added the -F (--fixed-strings) option.
1736        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1738        (l) Added the --colo(u)r option.
1740        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1741            is not present by default.
1743     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1744        items such as (?R) or (?1), when the recursion could match a number of
1745        alternatives. If it matched one of the alternatives, but subsequently,
1746        outside the recursion, there was a failure, the code tried to back up into
1747        the recursion. However, because of the way PCRE is implemented, this is not
1748        possible, and the result was an incorrect result from the match.
1750        In order to prevent this happening, the specification of recursion has
1751        been changed so that all such subpatterns are automatically treated as
1752        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1754     4. I had overlooked the fact that, in some locales, there are characters for
1755        which isalpha() is true but neither isupper() nor islower() are true. In
1756        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1757        and ordfeminine) are like this. This affected the treatment of \w and \W
1758        when they appeared in character classes, but not when they appeared outside
1759        a character class. The bit map for "word" characters is now created
1760        separately from the results of isalnum() instead of just taking it from the
1761        upper, lower, and digit maps. (Plus the underscore character, of course.)
1763     5. The above bug also affected the handling of POSIX character classes such as
1764        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1765        permanent tables. Instead, the bit maps for such a class were previously
1766        created as the appropriate unions of the upper, lower, and digit bitmaps.
1767        Now they are created by subtraction from the [[:word:]] class, which has
1768        its own bitmap.
1770     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1771        It is created by subtracting the vertical space characters (\x09, \x0a,
1772        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1773        subtraction was done in the overall bitmap for a character class, meaning
1774        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1775        be recognized. This bug has been fixed.
1777     7. Patches from the folks at Google:
1779          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1780          real life, but is still worth protecting against".
1782          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1783          regular expressions".
1785          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1786          have it.
1788          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1789          "configure" and the latter not, in order to fix a problem somebody had
1790          with compiling the Arg class on HP-UX.
1792          (e) Improve the error-handling of the C++ wrapper a little bit.
1794          (f) New tests for checking recursion limiting.
1796     8. The pcre_memmove() function, which is used only if the environment does not
1797        have a standard memmove() function (and is therefore rarely compiled),
1798        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1799        returning a result (though PCRE never actually uses the result).
1801     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1802        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1803        returned instead of calling malloc() with an overflowing number that would
1804        most likely cause subsequent chaos.
1806    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1808    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1809        with this option is matched, the nmatch and pmatch options of regexec() are
1810        ignored.
1812    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1813        provided in case anyone wants to the the POSIX interface with UTF-8
1814        strings.
1816    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1817        C++ linking (needed for some HP-UX environments).
1819    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1820        (unused parameter) and in the pcre_printint() function (omitted "default"
1821        switch label when the default is to do nothing).
1823    15. Added some code to make it possible, when PCRE is compiled as a C++
1824        library, to replace subject pointers for pcre_exec() with a smart pointer
1825        class, thus making it possible to process discontinuous strings.
1827    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1828        much the same function. They were added by different people who were trying
1829        to make PCRE easy to compile on non-Unix systems. It has been suggested
1830        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1831        for compiling on Windows systems. I have therefore replaced it with
1832        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1833        defaults to "extern" for C or "extern C" for C++, which works fine on
1834        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1835        SCOPE with something explicit in config.h. In addition:
1837        (a) pcreposix.h still had just "extern" instead of either of these macros;
1838            I have replaced it with PCRE_DATA_SCOPE.
1840        (b) Functions such as _pcre_xclass(), which are internal to the library,
1841            but external in the C sense, all had PCRE_EXPORT in their definitions.
1842            This is apparently wrong for the Windows case, so I have removed it.
1843            (It makes no difference on Unix-like systems.)
1845    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1846        of recursive calls to match(). This is different to MATCH_LIMIT because
1847        that limits the total number of calls to match(), not all of which increase
1848        the depth of recursion. Limiting the recursion depth limits the amount of
1849        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1850        when PCRE is compiled, and changed at run time. A patch from Google adds
1851        this functionality to the C++ interface.
1853    18. Changes to the handling of Unicode character properties:
1855        (a) Updated the table to Unicode 4.1.0.
1857        (b) Recognize characters that are not in the table as "Cn" (undefined).
1859        (c) I revised the way the table is implemented to a much improved format
1860            which includes recognition of ranges. It now supports the ranges that
1861            are defined in UnicodeData.txt, and it also amalgamates other
1862            characters into ranges. This has reduced the number of entries in the
1863            table from around 16,000 to around 3,000, thus reducing its size
1864            considerably. I realized I did not need to use a tree structure after
1865            all - a binary chop search is just as efficient. Having reduced the
1866            number of entries, I extended their size from 6 bytes to 8 bytes to
1867            allow for more data.
1869        (d) Added support for Unicode script names via properties such as \p{Han}.
1871    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1872        matching that character.
1874    20. When matching a repeated Unicode property with a minimum greater than zero,
1875        (for example \pL{2,}), PCRE could look past the end of the subject if it
1876        reached it while seeking the minimum number of characters. This could
1877        happen only if some of the characters were more than one byte long, because
1878        there is a check for at least the minimum number of bytes.
1880    21. Refactored the implementation of \p and \P so as to be more general, to
1881        allow for more different types of property in future. This has changed the
1882        compiled form incompatibly. Anybody with saved compiled patterns that use
1883        \p or \P will have to recompile them.
1885    22. Added "Any" and "L&" to the supported property types.
1887    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1888        but give a compile time error if the value is greater than 0xff.
1890    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1891        accidentally not being installed or uninstalled.
1893    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1894        made were to insert the current release number. This seemed silly, because
1895        it made things harder for people building PCRE on systems that don't run
1896        "configure". I have turned pcre.h into a distributed file, no longer built
1897        by "configure", with the version identification directly included. There is
1898        no longer a pcre.h.in file.
1900        However, this change necessitated a change to the pcre-config script as
1901        well. It is built from pcre-config.in, and one of the substitutions was the
1902        release number. I have updated configure.ac so that ./configure now finds
1903        the release number by grepping pcre.h.
1905    26. Added the ability to run the tests under valgrind.
1908    Version 6.4 05-Sep-05
1909    ---------------------
1911     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1912        "--" to be printed when multiple files were scanned, even when none of the
1913        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1914        consider it to be a bug, and have restored the previous behaviour.
1916     2. A couple of code tidies to get rid of compiler warnings.
1918     3. The pcretest program used to cheat by referring to symbols in the library
1919        whose names begin with _pcre_. These are internal symbols that are not
1920        really supposed to be visible externally, and in some environments it is
1921        possible to suppress them. The cheating is now confined to including
1922        certain files from the library's source, which is a bit cleaner.
1924     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1925        file's purpose clearer.
1927     5. Reorganized pcre_ucp_findchar().
1930    Version 6.3 15-Aug-05
1931    ---------------------
1933     1. The file libpcre.pc.in did not have general read permission in the tarball.
1935     2. There were some problems when building without C++ support:
1937        (a) If C++ support was not built, "make install" and "make test" still
1938            tried to test it.
1940        (b) There were problems when the value of CXX was explicitly set. Some
1941            changes have been made to try to fix these, and ...
1943        (c) --disable-cpp can now be used to explicitly disable C++ support.
1945        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1946            backslash in a target when C++ was disabled. This confuses some
1947            versions of "make", apparently. Using an intermediate variable solves
1948            this. (Same for CPP_LOBJ.)
1950     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1951        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1952        necessary on certain architectures.
1954     4. Added a setting of -export-symbols-regex to the link command to remove
1955        those symbols that are exported in the C sense, but actually are local
1956        within the library, and not documented. Their names all begin with
1957        "_pcre_". This is not a perfect job, because (a) we have to except some
1958        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1959        available (and never for static libraries). I have made a note to try to
1960        find a way round (a) in the future.
1963    Version 6.2 01-Aug-05
1964    ---------------------
1966     1. There was no test for integer overflow of quantifier values. A construction
1967        such as {1111111111111111} would give undefined results. What is worse, if
1968        a minimum quantifier for a parenthesized subpattern overflowed and became
1969        negative, the calculation of the memory size went wrong. This could have
1970        led to memory overwriting.
1972     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1974     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1975        operating environments where this matters.
1977     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1978        PCRE options from within the C++ wrapper.
1980     5. Named capturing subpatterns were not being correctly counted when a pattern
1981        was compiled. This caused two problems: (a) If there were more than 100
1982        such subpatterns, the calculation of the memory needed for the whole
1983        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1984        back references of the form \12, where the number was greater than 9, were
1985        not recognized as back references, even though there were sufficient
1986        previous subpatterns.
1988     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1989        versions of gcc, e.g. 2.95.4.
1992    Version 6.1 21-Jun-05
1993    ---------------------
1995     1. There was one reference to the variable "posix" in pcretest.c that was not
1996        surrounded by "#if !defined NOPOSIX".
1998     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1999        the cross-check on the old pcre_info() function, for the benefit of the
2000        cut-down version of PCRE that is currently imported into Exim.
2002     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2003        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2004        patterns that start (?i) but I don't think that matters. The use of (?i) is
2005        just an example; this all applies to the other options as well.
2007     4. Since libtool seems to echo the compile commands it is issuing, the output
2008        from "make" can be reduced a bit by putting "@" in front of each libtool
2009        compile command.
2011     5. Patch from the folks at Google for configure.in to be a bit more thorough
2012        in checking for a suitable C++ installation before trying to compile the
2013        C++ stuff. This should fix a reported problem when a compiler was present,
2014        but no suitable headers.
2016     6. The man pages all had just "PCRE" as their title. I have changed them to
2017        be the relevant file name. I have also arranged that these names are
2018        retained in the file doc/pcre.txt, which is a concatenation in text format
2019        of all the man pages except the little individual ones for each function.
2021     7. The NON-UNIX-USE file had not been updated for the different set of source
2022        files that come with release 6. I also added a few comments about the C++
2023        wrapper.
2026    Version 6.0 07-Jun-05
2027    ---------------------
2029     1. Some minor internal re-organization to help with my DFA experiments.
2031     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2032        didn't matter for the library itself when fully configured, but did matter
2033        when compiling without UCP support, or within Exim, where the ucp files are
2034        not imported.
2036     3. Refactoring of the library code to split up the various functions into
2037        different source modules. The addition of the new DFA matching code (see
2038        below) to a single monolithic source would have made it really too
2039        unwieldy, quite apart from causing all the code to be include in a
2040        statically linked application, when only some functions are used. This is
2041        relevant even without the DFA addition now that patterns can be compiled in
2042        one application and matched in another.
2044        The downside of splitting up is that there have to be some external
2045        functions and data tables that are used internally in different modules of
2046        the library but which are not part of the API. These have all had their
2047        names changed to start with "_pcre_" so that they are unlikely to clash
2048        with other external names.
2050     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2051        a different (DFA) algorithm. Although it is slower than the original
2052        function, it does have some advantages for certain types of matching
2053        problem.
2055     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2056        including restarting after a partial match.
2058     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2059        defined when compiling for Windows was sent to me. I have put it into the
2060        code, though I have no means of testing or verifying it.
2062     7. Added the pcre_refcount() auxiliary function.
2064     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2065        match before or at the first newline in the subject string. In pcretest,
2066        the /f option on a pattern can be used to set this.
2068     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2069        would behave wrongly. This has been present in PCRE since release 4.0.
2071    10. A number of changes to the pcregrep command:
2073        (a) Refactored how -x works; insert ^(...)$ instead of setting
2074            PCRE_ANCHORED and checking the length, in preparation for adding
2075            something similar for -w.
2077        (b) Added the -w (match as a word) option.
2079        (c) Refactored the way lines are read and buffered so as to have more
2080            than one at a time available.
2082        (d) Implemented a pcregrep test script.
2084        (e) Added the -M (multiline match) option. This allows patterns to match
2085            over several lines of the subject. The buffering ensures that at least
2086            8K, or the rest of the document (whichever is the shorter) is available
2087            for matching (and similarly the previous 8K for lookbehind assertions).
2089        (f) Changed the --help output so that it now says
2091              -w, --word-regex(p)
2093            instead of two lines, one with "regex" and the other with "regexp"
2094            because that confused at least one person since the short forms are the
2095            same. (This required a bit of code, as the output is generated
2096            automatically from a table. It wasn't just a text change.)
2098        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2099            option but starts with a hyphen. Could be a pattern or a path name
2100            starting with a hyphen, for instance.
2102        (h) "-" can be given as a file name to represent stdin.
2104        (i) When file names are being printed, "(standard input)" is used for
2105            the standard input, for compatibility with GNU grep. Previously
2106            "<stdin>" was used.
2108        (j) The option --label=xxx can be used to supply a name to be used for
2109            stdin when file names are being printed. There is no short form.
2111        (k) Re-factored the options decoding logic because we are going to add
2112            two more options that take data. Such options can now be given in four
2113            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2115        (l) Added the -A, -B, and -C options for requesting that lines of context
2116            around matches be printed.
2118        (m) Added the -L option to print the names of files that do not contain
2119            any matching lines, that is, the complement of -l.
2121        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2122            continue to scan other files.
2124        (o) The -s option was incorrectly implemented. For compatibility with other
2125            greps, it now suppresses the error message for a non-existent or non-
2126            accessible file (but not the return code). There is a new option called
2127            -q that suppresses the output of matching lines, which was what -s was
2128            previously doing.
2130        (p) Added --include and --exclude options to specify files for inclusion
2131            and exclusion when recursing.
2133    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2134        Hopefully, it now does.
2136    12. Missing cast in pcre_study().
2138    13. Added an "uninstall" target to the makefile.
2140    14. Replaced "extern" in the function prototypes in Makefile.in with
2141        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2142        world, but is set differently for Windows.
2144    15. Added a second compiling function called pcre_compile2(). The only
2145        difference is that it has an extra argument, which is a pointer to an
2146        integer error code. When there is a compile-time failure, this is set
2147        non-zero, in addition to the error test pointer being set to point to an
2148        error message. The new argument may be NULL if no error number is required
2149        (but then you may as well call pcre_compile(), which is now just a
2150        wrapper). This facility is provided because some applications need a
2151        numeric error indication, but it has also enabled me to tidy up the way
2152        compile-time errors are handled in the POSIX wrapper.
2154    16. Added VPATH=.libs to the makefile; this should help when building with one
2155        prefix path and installing with another. (Or so I'm told by someone who
2156        knows more about this stuff than I do.)
2158    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2159        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2160        match everything, including newlines. This is not POSIX-compatible, but
2161        somebody wanted the feature. From pcretest it can be activated by using
2162        both the P and the s flags.
2164    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2166    19. libpcre.pc was being incorrectly installed as executable.
2168    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2169        it now also looks for '\r' so that it will work unmodified on Windows.
2171    21. Added Google's contributed C++ wrapper to the distribution.
2173    22. Added some untidy missing memory free() calls in pcretest, to keep
2174        Electric Fence happy when testing.
2178    Version 5.0 13-Sep-04
2179    ---------------------
2181     1. Internal change: literal characters are no longer packed up into items
2182        containing multiple characters in a single byte-string. Each character
2183        is now matched using a separate opcode. However, there may be more than one
2184        byte in the character in UTF-8 mode.
2186     2. The pcre_callout_block structure has two new fields: pattern_position and
2187        next_item_length. These contain the offset in the pattern to the next match
2188        item, and its length, respectively.
2190     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2191        insertion of callouts before each pattern item. Added the /C option to
2192        pcretest to make use of this.
2194     4. On the advice of a Windows user, the lines
2196          #if defined(_WIN32) || defined(WIN32)
2197          _setmode( _fileno( stdout ), 0x8000 );
2198          #endif  /* defined(_WIN32) || defined(WIN32) */
2200        have been added to the source of pcretest. This apparently does useful
2201        magic in relation to line terminators.
2203     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2204        for the benefit of those environments where the "b" makes a difference.
2206     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2207        to know about it. I have put a hack into configure.in that adds in code
2208        to set GCC=yes if CC=icc. This seems to end up at a point in the
2209        generated configure script that is early enough to affect the setting of
2210        compiler options, which is what is needed, but I have no means of testing
2211        whether it really works. (The user who reported this had patched the
2212        generated configure script, which of course I cannot do.)
2214        LATER: After change 22 below (new libtool files), the configure script
2215        seems to know about icc (and also ecc). Therefore, I have commented out
2216        this hack in configure.in.
2218     7. Added support for pkg-config (2 patches were sent in).
2220     8. Negated POSIX character classes that used a combination of internal tables
2221        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2222        [[:^ascii]]. Typically, they would match almost any characters. The other
2223        POSIX classes were not broken in this way.
2225     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2226        to find the match, as PCRE was deluded into thinking that the match had to
2227        start at the start point or following a newline. The same bug applied to
2228        patterns with negative forward assertions or any backward assertions
2229        preceding ".*" at the start, unless the pattern required a fixed first
2230        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2232    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2233        starting at the last subject character, bytes beyond the end of the subject
2234        string were read.
2236    11. Renamed the variable "class" as "classbits" to make life easier for C++
2237        users. (Previously there was a macro definition, but it apparently wasn't
2238        enough.)
2240    12. Added the new field "tables" to the extra data so that tables can be passed
2241        in at exec time, or the internal tables can be re-selected. This allows
2242        a compiled regex to be saved and re-used at a later time by a different
2243        program that might have everything at different addresses.
2245    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2246        -R library as well as a -L library.
2248    14. The debugging options of pcretest (-d on the command line or D on a
2249        pattern) showed incorrect output for anything following an extended class
2250        that contained multibyte characters and which was followed by a quantifier.
2252    15. Added optional support for general category Unicode character properties
2253        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2254        support. It adds about 90K to the size of the library. The meanings of the
2255        inbuilt class escapes such as \d and \s have NOT been changed.
2257    16. Updated pcredemo.c to include calls to free() to release the memory for the
2258        compiled pattern.
2260    17. The generated file chartables.c was being created in the source directory
2261        instead of in the building directory. This caused the build to fail if the
2262        source directory was different from the building directory, and was
2263        read-only.
2265    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2266        file. No doubt somebody will tell me if they don't make sense... Also added
2267        Dan Mooney's comments about building on OpenVMS.
2269    19. Added support for partial matching via the PCRE_PARTIAL option for
2270        pcre_exec() and the \P data escape in pcretest.
2272    20. Extended pcretest with 3 new pattern features:
2274        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2275              write the compiled pattern to the file whose name is "rest-of-line".
2276              This is a straight binary dump of the data, with the saved pointer to
2277              the character tables forced to be NULL. The study data, if any, is
2278              written too. After writing, pcretest reads a new pattern.
2280        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2281              compiled pattern from the given file. There must not be any
2282              occurrences of "<" in the file name (pretty unlikely); if there are,
2283              pcretest will instead treat the initial "<" as a pattern delimiter.
2284              After reading in the pattern, pcretest goes on to read data lines as
2285              usual.
2287        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2288              and 16-bit fields in a compiled pattern, to simulate a pattern that
2289              was compiled on a host of opposite endianness.
2291    21. The pcre-exec() function can now cope with patterns that were compiled on
2292        hosts of opposite endianness, with this restriction:
2294          As for any compiled expression that is saved and used later, the tables
2295          pointer field cannot be preserved; the extra_data field in the arguments
2296          to pcre_exec() should be used to pass in a tables address if a value
2297          other than the default internal tables were used at compile time.
2299    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2300        now diagnosed as an error. Previously, most of the time, a negative number
2301        would have been treated as zero, but if in addition "ovector" was passed as
2302        NULL, a crash could occur.
2304    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2305        new versions from the libtool 1.5 distribution (the last one is a copy of
2306        a file called libtool.m4). This seems to have fixed the need to patch
2307        "configure" to support Darwin 1.3 (which I used to do). However, I still
2308        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2309        workstation).
2311    24. Changed the PCRE licence to be the more standard "BSD" licence.
2314    Version 4.5 01-Dec-03
2315    ---------------------
2317     1. There has been some re-arrangement of the code for the match() function so
2318        that it can be compiled in a version that does not call itself recursively.
2319        Instead, it keeps those local variables that need separate instances for
2320        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2321        needs to "recurse". Keeping track of where control must go is done by means
2322        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2323        hide most of the details from the main code, and operates only if
2324        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2325        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2326        operating.
2328        To make it easier for callers to provide specially tailored get/free
2329        functions for this usage, two new functions, pcre_stack_malloc, and
2330        pcre_stack_free, are used. They are always called in strict stacking order,
2331        and the size of block requested is always the same.
2333        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2334        PCRE has been compiled to use the stack or the heap for recursion. The
2335        -C option of pcretest uses this to show which version is compiled.
2337        A new data escape \S, is added to pcretest; it causes the amounts of store
2338        obtained and freed by both kinds of malloc/free at match time to be added
2339        to the output.
2341     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2342        what's available on my current Linux desktop machine.
2344     3. When matching a UTF-8 string, the test for a valid string at the start has
2345        been extended. If start_offset is not zero, PCRE now checks that it points
2346        to a byte that is the start of a UTF-8 character. If not, it returns
2347        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2348        this is necessary because there may be backward assertions in the pattern.
2349        When matching the same subject several times, it may save resources to use
2350        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2352     4. The code for checking the validity of UTF-8 strings has been tightened so
2353        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2354        containing "overlong sequences".
2356     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2357        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2358        should have been "&", but it just so happened that all the cases this let
2359        through by mistake were picked up later in the function.
2361     6. I had used a variable called "isblank" - this is a C99 function, causing
2362        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2364     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2365        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2366        so the version is shown; (c) stop "make test" echoing "./RunTest".
2368     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2370     9. The prototype for memmove() for systems that don't have it was using
2371        size_t, but the inclusion of the header that defines size_t was later. I've
2372        moved the #includes for the C headers earlier to avoid this.
2374    10. Added some adjustments to the code to make it easier to compiler on certain
2375        special systems:
2377          (a) Some "const" qualifiers were missing.
2378          (b) Added the macro EXPORT before all exported functions; by default this
2379              is defined to be empty.
2380          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2381              that it reads its output file name as an argument instead of writing
2382              to the standard output and assuming this can be redirected.
2384    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2385        class containing characters with values greater than 255, PCRE compilation
2386        went into a loop.
2388    12. A recursive reference to a subpattern that was within another subpattern
2389        that had a minimum quantifier of zero caused PCRE to crash. For example,
2390        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2391        recursion. If the recursively-called subpattern itself had a zero repeat,
2392        that was OK.
2394    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2395        buffer into which it was copied (for escape processing) was still set at
2396        1024, so long lines caused crashes.
2398    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2399        "internal error: code overflow...". This applied to any character class
2400        that was followed by a possessive quantifier.
2402    15. Modified the Makefile to add libpcre.la as a prerequisite for
2403        libpcreposix.la because I was told this is needed for a parallel build to
2404        work.
2406    16. If a pattern that contained .* following optional items at the start was
2407        studied, the wrong optimizing data was generated, leading to matching
2408        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2409        matching string must start with a or b or c. The correct conclusion for
2410        this pattern is that a match can start with any character.
2413    Version 4.4 13-Aug-03
2414    ---------------------
2416     1. In UTF-8 mode, a character class containing characters with values between
2417        127 and 255 was not handled correctly if the compiled pattern was studied.
2418        In fixing this, I have also improved the studying algorithm for such
2419        classes (slightly).
2421     2. Three internal functions had redundant arguments passed to them. Removal
2422        might give a very teeny performance improvement.
2424     3. Documentation bug: the value of the capture_top field in a callout is *one
2425        more than* the number of the hightest numbered captured substring.
2427     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2428        in incorrectly linking with a previously installed version. They now link
2429        explicitly with libpcre.la.
2431     5. configure.in no longer needs to recognize Cygwin specially.
2433     6. A problem in pcre.in for Windows platforms is fixed.
2435     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2436        pcretest, it used to include the size of the study block as part of its
2437        output. Unfortunately, the structure contains a field that has a different
2438        size on different hardware architectures. This meant that the tests that
2439        showed this size failed. As the block is currently always of a fixed size,
2440        this information isn't actually particularly useful in pcretest output, so
2441        I have just removed it.
2443     8. Three pre-processor statements accidentally did not start in column 1.
2444        Sadly, there are *still* compilers around that complain, even though
2445        standard C has not required this for well over a decade. Sigh.
2447     9. In pcretest, the code for checking callouts passed small integers in the
2448        callout_data field, which is a void * field. However, some picky compilers
2449        complained about the casts involved for this on 64-bit systems. Now
2450        pcretest passes the address of the small integer instead, which should get
2451        rid of the warnings.
2453    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2454        both compile and run time, and gives an error if an invalid UTF-8 sequence
2455        is found. There is a option for disabling this check in cases where the
2456        string is known to be correct and/or the maximum performance is wanted.
2458    11. In response to a bug report, I changed one line in Makefile.in from
2460            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2461        to
2462            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2464        to look similar to other lines, but I have no way of telling whether this
2465        is the right thing to do, as I do not use Windows. No doubt I'll get told
2466        if it's wrong...
2469    Version 4.3 21-May-03
2470    ---------------------
2472    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2473       Makefile.
2475    2. Some refactoring to improve the quality of the code:
2477       (i)   The utf8_table... variables are now declared "const".
2479       (ii)  The code for \cx, which used the "case flipping" table to upper case
2480             lower case letters, now just substracts 32. This is ASCII-specific,
2481             but the whole concept of \cx is ASCII-specific, so it seems
2482             reasonable.
2484       (iii) PCRE was using its character types table to recognize decimal and
2485             hexadecimal digits in the pattern. This is silly, because it handles
2486             only 0-9, a-f, and A-F, but the character types table is locale-
2487             specific, which means strange things might happen. A private
2488             table is now used for this - though it costs 256 bytes, a table is
2489             much faster than multiple explicit tests. Of course, the standard
2490             character types table is still used for matching digits in subject
2491             strings against \d.
2493       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2494             ending in _t are). So I've renamed it as ESC_tee.
2496    3. The first argument for regexec() in the POSIX wrapper should have been
2497       defined as "const".
2499    4. Changed pcretest to use malloc() for its buffers so that they can be
2500       Electric Fenced for debugging.
2502    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2503       to read one or more bytes before the start of the subject string. Often this
2504       had no effect on PCRE's behaviour, but in some circumstances it could
2505       provoke a segmentation fault.
2507    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2508       to try to read one or more bytes before the start of the subject string.
2510    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2511       UTF-8 support could misbehave in various ways if the subject string
2512       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2513       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2514       back over UTF-8 characters.)
2517    Version 4.2 14-Apr-03
2518    ---------------------
2520    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2522    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2523         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2524         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2525         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2526         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2527           and BUILD_EXEEXT
2528         Note: automatic setting of the BUILD variables is not yet working
2529         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2530           compile-time but not at link-time
2531         [LINK]: use for linking executables only
2532         make different versions for Windows and non-Windows
2533         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2534           libraries
2535         [LINK_FOR_BUILD]: new variable
2536         [OBJEXT]: use throughout
2537         [EXEEXT]: use throughout
2538         <winshared>: new target
2539         <wininstall>: new target
2540         <dftables.o>: use native compiler
2541         <dftables>: use native linker
2542         <install>: handle Windows platform correctly
2543         <clean>: ditto
2544         <check>: ditto
2545         copy DLL to top builddir before testing
2547       As part of these changes, -no-undefined was removed again. This was reported
2548       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2549       in any case.
2551    3. Some tidies to get rid of compiler warnings:
2553       . In the match_data structure, match_limit was an unsigned long int, whereas
2554         match_call_count was an int. I've made them both unsigned long ints.
2556       . In pcretest the fact that a const uschar * doesn't automatically cast to
2557         a void * provoked a warning.
2559       . Turning on some more compiler warnings threw up some "shadow" variables
2560         and a few more missing casts.
2562    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2563       option, a class that contained a single character with a value between 128
2564       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2566    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2567       option, a class that contained several characters, but with at least one
2568       whose value was between 128 and 255 caused PCRE to crash.
2571    Version 4.1 12-Mar-03
2572    ---------------------
2574    1. Compiling with gcc -pedantic found a couple of places where casts were
2575    needed, and a string in dftables.c that was longer than standard compilers are
2576    required to support.
2578    2. Compiling with Sun's compiler found a few more places where the code could
2579    be tidied up in order to avoid warnings.
2581    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2582    first of these names is deprecated in the latest Autoconf in favour of the name
2583    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2584    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2585    analogy I have changed it to CFLAGS_FOR_BUILD.
2587    4. Added -no-undefined to the linking command in the Makefile, because this is
2588    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2589    linking step for the pcreposix library.
2591    5. PCRE was failing to diagnose the case of two named groups with the same
2592    name.
2594    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2595    literal character that is needed in the subject for a match, and scans along to
2596    ensure that it is present before embarking on the full matching process. This
2597    saves time in cases of nested unlimited repeats that are never going to match.
2598    Problem: the scan can take a lot of time if the subject is very long (e.g.
2599    megabytes), thus penalizing straightforward matches. It is now done only if the
2600    amount of subject to be scanned is less than 1000 bytes.
2602    7. A lesser problem with the same optimization is that it was recording the
2603    first character of an anchored pattern as "needed", thus provoking a search
2604    right along the subject, even when the first match of the pattern was going to
2605    fail. The "needed" character is now not set for anchored patterns, unless it
2606    follows something in the pattern that is of non-fixed length. Thus, it still
2607    fulfils its original purpose of finding quick non-matches in cases of nested
2608    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2611    Version 4.0 17-Feb-03
2612    ---------------------
2614    1. If a comment in an extended regex that started immediately after a meta-item
2615    extended to the end of string, PCRE compiled incorrect data. This could lead to
2616    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2618    2. Moved to autoconf 2.53 and libtool 1.4.2.
2620    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2621    the special perltest8 script is no longer needed - all the tests can be run
2622    from a single perltest script.
2624    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2625    by \s. It has now been removed in PCRE. This means it isn't recognized as
2626    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2627    class [:space:] *does* include VT, thereby creating a mess.
2629    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2630    space and tab.
2632    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2633    its new features into the main test script, reducing the number of scripts.
2635    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2636    were backward compatible, and made the (?i) apply to the whole pattern, as if
2637    /i were given. Now it behaves more logically, and applies the option setting
2638    only to what follows. PCRE has been changed to follow suit. However, if it
2639    finds options settings right at the start of the pattern, it extracts them into
2640    the global options, as before. Thus, they show up in the info data.
2642    8. Added support for the \Q...\E escape sequence. Characters in between are
2643    treated as literals. This is slightly different from Perl in that $ and @ are
2644    also handled as literals inside the quotes. In Perl, they will cause variable
2645    interpolation. Note the following examples:
2647        Pattern            PCRE matches      Perl matches
2649        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2650        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2651        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2653    For compatibility with Perl, \Q...\E sequences are recognized inside character
2654    classes as well as outside them.
2656    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2657    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2658    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2659    signed/unsigned warnings.
2661    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2662    option for pcretest, so I've replaced it by a simple function that does just
2663    that job.
2665    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2666    "pcregrep -".
2668    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2669    Java package. This provides some syntactic sugar for simple cases of what my
2670    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2671    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2672    item, you can use this simplified notation. Note that only makes sense with
2673    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2674    greediness, whatever the setting of the PCRE_UNGREEDY option.
2676    13. A change of greediness default within a pattern was not taking effect at
2677    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2678    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2679    was abstracted outside.
2681    14. PCRE now supports the \G assertion. It is true when the current matching
2682    position is at the start point of the match. This differs from \A when the
2683    starting offset is non-zero. Used with the /g option of pcretest (or similar
2684    code), it works in the same way as it does for Perl's /g option. If all
2685    alternatives of a regex begin with \G, the expression is anchored to the start
2686    match position, and the "anchored" flag is set in the compiled expression.
2688    15. Some bugs concerning the handling of certain option changes within patterns
2689    have been fixed. These applied to options other than (?ims). For example,
2690    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2691    been the other way round. Some of this was related to change 7 above.
2693    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2694    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2695    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2696    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2698    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2699    mode. Unlike ".", it always matches newline, whatever the setting of
2700    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2701    assertions. Perl allows it, but it doesn't (in general) work because it can't
2702    calculate the length of the lookbehind. At least, that's the case for Perl
2703    5.8.0 - I've been told they are going to document that it doesn't work in
2704    future.
2706    18. Added an error diagnosis for escapes that PCRE does not support: these are
2707    \L, \l, \N, \P, \p, \U, \u, and \X.
2709    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2710    reading past the end of the pattern in cases such as /[abcd/.
2712    20. PCRE was getting more memory than necessary for patterns with classes that
2713    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2715    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2716    compiling PCRE for use with Virtual Pascal.
2718    22. Small fix to the Makefile to make it work properly if the build is done
2719    outside the source tree.
2721    23. Added a new extension: a condition to go with recursion. If a conditional
2722    subpattern starts with (?(R) the "true" branch is used if recursion has
2723    happened, whereas the "false" branch is used only at the top level.
2725    24. When there was a very long string of literal characters (over 255 bytes
2726    without UTF support, over 250 bytes with UTF support), the computation of how
2727    much memory was required could be incorrect, leading to segfaults or other
2728    strange effects.
2730    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2731    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2732    there was a subsequent back reference to those brackets. This meant that, for
2733    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2734    possible to check for precisely this case. All we can do is abandon the
2735    optimization if .* occurs inside capturing brackets when there are any back
2736    references whatsoever. (See below for a better fix that came later.)
2738    26. The handling of the optimization for finding the first character of a
2739    non-anchored pattern, and for finding a character that is required later in the
2740    match were failing in some cases. This didn't break the matching; it just
2741    failed to optimize when it could. The way this is done has been re-implemented.
2743    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2745    28. Added a new feature that provides some of the functionality that Perl
2746    provides with (?{...}). The facility is termed a "callout". The way it is done
2747    in PCRE is for the caller to provide an optional function, by setting
2748    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2749    global variable. By default it is unset, which disables all calling out. To get
2750    the function called, the regex must include (?C) at appropriate points. This
2751    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2752    This provides a means of identifying different callout points. When PCRE
2753    reaches such a point in the regex, if pcre_callout has been set, the external
2754    function is called. It is provided with data in a structure called
2755    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2756    matching continues; if it returns a non-zero value, the match at the current
2757    point fails. However, backtracking will occur if possible. [This was changed
2758    later and other features added - see item 49 below.]
2760    29. pcretest is upgraded to test the callout functionality. It provides a
2761    callout function that displays information. By default, it shows the start of
2762    the match and the current position in the text. There are some new data escapes
2763    to vary what happens:
2765        \C+         in addition, show current contents of captured substrings
2766        \C-         do not supply a callout function
2767        \C!n        return 1 when callout number n is reached
2768        \C!n!m      return 1 when callout number n is reached for the mth time
2770    30. If pcregrep was called with the -l option and just a single file name, it
2771    output "<stdin>" if a match was found, instead of the file name.
2773    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2774    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2775    pcre_exec(). This saves a malloc/free per call. The default value of
2776    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2777    when configuring.
2779    32. The default maximum size of a compiled pattern is 64K. There have been a
2780    few cases of people hitting this limit. The code now uses macros to handle the
2781    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2782    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2783    configuring. Tests 2 and 5 work only with 2-byte links because they output
2784    debugging information about compiled patterns.
2786    33. Internal code re-arrangements:
2788    (a) Moved the debugging function for printing out a compiled regex into
2789        its own source file (printint.c) and used #include to pull it into
2790        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2791        separate copies.
2793    (b) Defined the list of op-code names for debugging as a macro in
2794        internal.h so that it is next to the definition of the opcodes.
2796    (c) Defined a table of op-code lengths for simpler skipping along compiled
2797        code. This is again a macro in internal.h so that it is next to the
2798        definition of the opcodes.
2800    34. Added support for recursive calls to individual subpatterns, along the
2801    lines of Robin Houston's patch (but implemented somewhat differently).
2803    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2804    allow it to read and process whole directories in Win32. This code was
2805    contributed by Lionel Fourquaux; it has not been tested by me.
2807    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2808    used to name a group. Names consist of alphanumerics and underscores, and must
2809    be unique. Back references use the syntax (?P=name) and recursive calls use
2810    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2811    numbers. The function pcre_fullinfo() can be used after compilation to extract
2812    a name/number map. There are three relevant calls:
2814      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2815      PCRE_INFO_NAMECOUNT            yields the number of entries
2816      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2818    The map is a vector of fixed-size entries. The size of each entry depends on
2819    the length of the longest name used. The first two bytes of each entry are the
2820    group number, most significant byte first. There follows the corresponding
2821    name, zero terminated. The names are in alphabetical order.
2823    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2824    case instead of 255. Making it the same both with and without UTF-8 support
2825    means that the same test output works with both.
2827    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2828    calling malloc() with a zero argument.
2830    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2831    optimization. I've improved things by keeping a bitmap of backreferences with
2832    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2833    fact referenced, the optimization can be applied. It is unlikely that a
2834    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2835    the match to follow \n) will appear inside brackets with a number greater than
2836    31, but if it does, any back reference > 31 suppresses the optimization.
2838    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2839    of disabling numbered capturing parentheses. Any opening parenthesis that is
2840    not followed by ? behaves as if it were followed by ?: but named parentheses
2841    can still be used for capturing (and they will acquire numbers in the usual
2842    way).
2844    41. Redesigned the return codes from the match() function into yes/no/error so
2845    that errors can be passed back from deep inside the nested calls. A malloc
2846    failure while inside a recursive subpattern call now causes the
2847    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2849    42. It is now possible to set a limit on the number of times the match()
2850    function is called in a call to pcre_exec(). This facility makes it possible to
2851    limit the amount of recursion and backtracking, though not in a directly
2852    obvious way, because the match() function is used in a number of different
2853    circumstances. The count starts from zero for each position in the subject
2854    string (for non-anchored patterns). The default limit is, for compatibility, a
2855    large number, namely 10 000 000. You can change this in two ways:
2857    (a) When configuring PCRE before making, you can use --with-match-limit=n
2858        to set a default value for the compiled library.
2860    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2861        a different value is set. See 45 below.
2863    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2865    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2866    of things that can be changed at compile time. The first argument specifies
2867    what is wanted and the second points to where the information is to be placed.
2868    The current list of available information is:
2870      PCRE_CONFIG_UTF8
2872    The output is an integer that is set to one if UTF-8 support is available;
2873    otherwise it is set to zero.
2877    The output is an integer that it set to the value of the code that is used for
2878    newline. It is either LF (10) or CR (13).
2882    The output is an integer that contains the number of bytes used for internal
2883    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2887    The output is an integer that contains the threshold above which the POSIX
2888    interface uses malloc() for output vectors. See item 31 above.
2892    The output is an unsigned integer that contains the default limit of the number
2893    of match() calls in a pcre_exec() execution. See 42 above.
2895    44. pcretest has been upgraded by the addition of the -C option. This causes it
2896    to extract all the available output from the new pcre_config() function, and to
2897    output it. The program then exits immediately.
2899    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2900    order to support additional features. One way would have been to define
2901    pcre_exec2() (for example) with extra arguments, but this would not have been
2902    extensible, and would also have required all calls to the original function to
2903    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2904    is used for passing in "extra" data from pcre_study().
2906    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2907    contains the following fields:
2909      flags         a bitmap indicating which of the following fields are set
2910      study_data    opaque data from pcre_study()
2911      match_limit   a way of specifying a limit on match() calls for a specific
2912                      call to pcre_exec()
2913      callout_data  data for callouts (see 49 below)
2915    The flag bits are also defined in pcre.h, and are
2921    The pcre_study() function now returns one of these new pcre_extra blocks, with
2922    the actual study data pointed to by the study_data field, and the
2923    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2924    before. That is, this change is entirely upwards-compatible and requires no
2925    change to existing code.
2927    If you want to pass in additional data to pcre_exec(), you can either place it
2928    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2929    block.
2931    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2932    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2933    times with different match limits, until it finds the minimum value needed for
2934    pcre_exec() to complete. The value is then output. This can be instructive; for
2935    most simple matches the number is quite small, but for pathological cases it
2936    gets very large very quickly.
2938    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2939    returns the size of the data block pointed to by the study_data field in a
2940    pcre_extra block, that is, the value that was passed as the argument to
2941    pcre_malloc() when PCRE was getting memory in which to place the information
2942    created by pcre_study(). The fourth argument should point to a size_t variable.
2943    pcretest has been extended so that this information is shown after a successful
2944    pcre_study() call when information about the compiled regex is being displayed.
2946    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2947    because what follows is always an absolute path. (Later: it turns out that this
2948    is more than cosmetic for MinGW, because it doesn't like empty path
2949    components.)
2951    49. Some changes have been made to the callout feature (see 28 above):
2953    (i)  A callout function now has three choices for what it returns:
2955           0  =>  success, carry on matching
2956         > 0  =>  failure at this point, but backtrack if possible
2957         < 0  =>  serious error, return this value from pcre_exec()
2959         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2960         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2961         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2962         use by callout functions. It will never be used by PCRE itself.
2964    (ii) The pcre_extra structure (see 45 above) has a void * field called
2965         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2966         pcre_callout_block structure has a field of the same name. The contents of
2967         the field passed in the pcre_extra structure are passed to the callout
2968         function in the corresponding field in the callout block. This makes it
2969         easier to use the same callout-containing regex from multiple threads. For
2970         testing, the pcretest program has a new data escape
2972           \C*n        pass the number n (may be negative) as callout_data
2974         If the callout function in pcretest receives a non-zero value as
2975         callout_data, it returns that value.
2977    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2978    there were some redundant $(CFLAGS) in commands that are now specified as
2979    $(LINK), which already includes $(CFLAGS).
2981    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2982    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2983    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2984    one-byte characters throughout. Note that case-insensitive matching applies
2985    only to characters whose values are less than 256. PCRE doesn't support the
2986    notion of cases for higher-valued characters.
2988    (i)   A character class whose characters are all within 0-255 is handled as
2989          a bit map, and the map is inverted for negative classes. Previously, a
2990          character > 255 always failed to match such a class; however it should
2991          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2993    (ii)  A negated character class with a single character < 255 is coded as
2994          "not this character" (OP_NOT). This wasn't working properly when the test
2995          character was multibyte, either singly or repeated.
2997    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2998          mode, for example: \x{100}{2,3}.
3000    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3001          singly or repeated) now correctly test multibyte characters. However,
3002          PCRE doesn't recognize any characters with values greater than 255 as
3003          digits, spaces, or word characters. Such characters always match \D, \S,
3004          and \W, and never match \d, \s, or \w.
3006    (v)   Classes may now contain characters and character ranges with values
3007          greater than 255. For example: [ab\x{100}-\x{400}].
3009    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
3010          PCRE in UTF-8 mode.
3012    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3013    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3014    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3015    value.)
3017    53. The single man page has become too large. I have therefore split it up into
3018    a number of separate man pages. These also give rise to individual HTML pages;
3019    these are now put in a separate directory, and there is an index.html page that
3020    lists them all. Some hyperlinking between the pages has been installed.
3022    54. Added convenience functions for handling named capturing parentheses.
3024    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3025    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3026    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3027    are faulted.
3029    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3030    calling configure. These values are used when compiling the dftables.c program
3031    which is run to generate the source of the default character tables. They
3032    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3033    you will need to set these values.
3035    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3038    Version 3.9 02-Jan-02
3039    ---------------------
3041    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3043    2. If --disable-static was given, the building process failed when trying to
3044    build pcretest and pcregrep. (For some reason it was using libtool to compile
3045    them, which is not right, as they aren't part of the library.)
3048  Version 3.8 18-Dec-01  Version 3.8 18-Dec-01
3049  ---------------------  ---------------------

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