ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 61 by nigel, Sat Feb 24 21:39:58 2007 UTC revision 479 by ph10, Sun Jan 3 16:31:39 2010 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 3.0 02-Jan-02  Version 8.01 11-Dec-09
5    ----------------------
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
12    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13        the pattern is reset in the first branch, pcre_compile() failed with
14        "internal error: code overflow at offset...". This happened only when
15        the reset was to the original external option setting. (An optimization
16        abstracts leading options settings into an external setting, which was the
17        cause of this.)
19    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21        assertion pattern did not match (meaning that the assertion was true), it
22        was incorrectly treated as false if the SKIP had been reached during the
23        matching. This also applied to assertions used as conditions.
25    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
26        assertion subpattern, including such a pattern used as a condition,
27        unpredictable results occurred, instead of the error return
30    5.  The C++ GlobalReplace function was not working like Perl for the special
31        situation when an empty string is matched. It now does the fancy magic
32        stuff that is necessary.
34    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
35        removed. (These were left over from very, very early versions of PCRE.)
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
40        (a) Change DEBUG to PCRE_DEBUG.
42        (b) In pcre_compile(), rename the member of the "branch_chain" structure
43            called "current" as "current_branch", to prevent a collision with the
44            Linux macro when compiled as a kernel module.
46        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
47            prevent a collision with the Linux macro when compiled as a kernel
48            module.
50    8.  In pcre_compile() there are some checks for integer overflows that used to
51        cast potentially large values to (double). This has been changed to that
52        when building, a check for int64_t is made, and if it is found, it is used
53        instead, thus avoiding the use of floating point arithmetic. (There is no
54        other use of FP in PCRE.) If int64_t is not found, the fallback is to
55        double.
57    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
58        2005 (difference between two addresses compared to an unsigned value).
60    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
61        custom one, because of the following reported problem in Windows:
63          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
64            under Win32.
65          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
66            therefore missing the function definition.
67          - The compiler thus generates a "C" signature for the test function.
68          - The linker fails to find the "C" function.
69          - PCRE fails to configure if asked to do so against libbz2.
71    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
72        messages were output:
74          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
75          rerunning libtoolize, to keep the correct libtool macros in-tree.
76          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
78        I have done both of these things.
82    Version 8.00 19-Oct-09
83    ----------------------
85    1.  The table for translating pcre_compile() error codes into POSIX error codes
86        was out-of-date, and there was no check on the pcre_compile() error code
87        being within the table. This could lead to an OK return being given in
88        error.
90    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
91        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
92        in a Windows environment.
94    3.  The pcregrep --count option prints the count for each file even when it is
95        zero, as does GNU grep. However, pcregrep was also printing all files when
96        --files-with-matches was added. Now, when both options are given, it prints
97        counts only for those files that have at least one match. (GNU grep just
98        prints the file name in this circumstance, but including the count seems
99        more useful - otherwise, why use --count?) Also ensured that the
100        combination -clh just lists non-zero counts, with no names.
102    4.  The long form of the pcregrep -F option was incorrectly implemented as
103        --fixed_strings instead of --fixed-strings. This is an incompatible change,
104        but it seems right to fix it, and I didn't think it was worth preserving
105        the old behaviour.
107    5.  The command line items --regex=pattern and --regexp=pattern were not
108        recognized by pcregrep, which required --regex pattern or --regexp pattern
109        (with a space rather than an '='). The man page documented the '=' forms,
110        which are compatible with GNU grep; these now work.
112    6.  No libpcreposix.pc file was created for pkg-config; there was just
113        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
115    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
116        when UCP support is not needed, by modifying the Python script that
117        generates it from Unicode data files. This should not matter if the module
118        is correctly used as a library, but I received one complaint about 50K of
119        unwanted data. My guess is that the person linked everything into his
120        program rather than using a library. Anyway, it does no harm.
122    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
123        was a minimum greater than 1 for a wide character in a possessive
124        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
125        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
126        character. Chaos in the form of incorrect output or a compiling loop could
127        result.
129    9.  The restrictions on what a pattern can contain when partial matching is
130        requested for pcre_exec() have been removed. All patterns can now be
131        partially matched by this function. In addition, if there are at least two
132        slots in the offset vector, the offset of the earliest inspected character
133        for the match and the offset of the end of the subject are set in them when
134        PCRE_ERROR_PARTIAL is returned.
136    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
137        synonymous with PCRE_PARTIAL, for backwards compatibility, and
138        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
139        and may be more useful for multi-segment matching.
141    11. Partial matching with pcre_exec() is now more intuitive. A partial match
142        used to be given if ever the end of the subject was reached; now it is
143        given only if matching could not proceed because another character was
144        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
145        string "Z", which now yields "no match" instead of "partial match". In the
146        case of pcre_dfa_exec(), "no match" is given if every matching path for the
147        final character ended with (*FAIL).
149    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
150        if the pattern had a "must contain" character that was already found in the
151        earlier partial match, unless partial matching was again requested. For
152        example, with the pattern /dog.(body)?/, the "must contain" character is
153        "g". If the first part-match was for the string "dog", restarting with
154        "sbody" failed. This bug has been fixed.
156    13. The string returned by pcre_dfa_exec() after a partial match has been
157        changed so that it starts at the first inspected character rather than the
158        first character of the match. This makes a difference only if the pattern
159        starts with a lookbehind assertion or \b or \B (\K is not supported by
160        pcre_dfa_exec()). It's an incompatible change, but it makes the two
161        matching functions compatible, and I think it's the right thing to do.
163    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
164        so that the demonstration program is easily available in environments where
165        PCRE has not been installed from source.
167    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
168        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
169        library.
171    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
172        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
173        is not the first non-POSIX option to be added. Clearly some people find
174        these options useful.
176    17. If a caller to the POSIX matching function regexec() passes a non-zero
177        value for nmatch with a NULL value for pmatch, the value of
178        nmatch is forced to zero.
180    18. RunGrepTest did not have a test for the availability of the -u option of
181        the diff command, as RunTest does. It now checks in the same way as
182        RunTest, and also checks for the -b option.
184    19. If an odd number of negated classes containing just a single character
185        interposed, within parentheses, between a forward reference to a named
186        subpattern and the definition of the subpattern, compilation crashed with
187        an internal error, complaining that it could not find the referenced
188        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
189        [The bug was that it was starting one character too far in when skipping
190        over the character class, thus treating the ] as data rather than
191        terminating the class. This meant it could skip too much.]
193    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
194        /g option in pcretest when the pattern contains \K, which makes it possible
195        to have an empty string match not at the start, even when the pattern is
196        anchored. Updated pcretest and pcredemo to use this option.
198    21. If the maximum number of capturing subpatterns in a recursion was greater
199        than the maximum at the outer level, the higher number was returned, but
200        with unset values at the outer level. The correct (outer level) value is
201        now given.
203    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
204        PCRE did not set those parentheses (unlike Perl). I have now found a way to
205        make it do so. The string so far is captured, making this feature
206        compatible with Perl.
208    23. The tests have been re-organized, adding tests 11 and 12, to make it
209        possible to check the Perl 5.10 features against Perl 5.10.
211    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
212        pattern matches a fixed length string. PCRE did not allow this; now it
213        does. Neither allows recursion.
215    25. I finally figured out how to implement a request to provide the minimum
216        length of subject string that was needed in order to match a given pattern.
217        (It was back references and recursion that I had previously got hung up
218        on.) This code has now been added to pcre_study(); it finds a lower bound
219        to the length of subject needed. It is not necessarily the greatest lower
220        bound, but using it to avoid searching strings that are too short does give
221        some useful speed-ups. The value is available to calling programs via
222        pcre_fullinfo().
224    26. While implementing 25, I discovered to my embarrassment that pcretest had
225        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
226        study optimizations had never been tested with that matching function.
227        Oops. What is worse, even when it was passed study data, there was a bug in
228        pcre_dfa_exec() that meant it never actually used it. Double oops. There
229        were also very few tests of studied patterns with pcre_dfa_exec().
231    27. If (?| is used to create subpatterns with duplicate numbers, they are now
232        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
233        on the other side of the coin, they are no longer allowed to have different
234        names, because these cannot be distinguished in PCRE, and this has caused
235        confusion. (This is a difference from Perl.)
237    28. When duplicate subpattern names are present (necessarily with different
238        numbers, as required by 27 above), and a test is made by name in a
239        conditional pattern, either for a subpattern having been matched, or for
240        recursion in such a pattern, all the associated numbered subpatterns are
241        tested, and the overall condition is true if the condition is true for any
242        one of them. This is the way Perl works, and is also more like the way
243        testing by number works.
246    Version 7.9 11-Apr-09
247    ---------------------
249    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
250        (pcretest), all targets were linked against these libraries. This included
251        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
252        libraries. This caused unwanted dependencies to be created. This problem
253        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
254        pcretest is linked with readline.
256    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
257        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
258        moved outside it again, because FALSE and TRUE are already defined in AIX,
259        but BOOL is not.
261    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
262        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
264    4.  The pcregrep documentation said spaces were inserted as well as colons (or
265        hyphens) following file names and line numbers when outputting matching
266        lines. This is not true; no spaces are inserted. I have also clarified the
267        wording for the --colour (or --color) option.
269    5.  In pcregrep, when --colour was used with -o, the list of matching strings
270        was not coloured; this is different to GNU grep, so I have changed it to be
271        the same.
273    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
274        each matching line was coloured. Now it goes on to look for further matches
275        of any of the test patterns, which is the same behaviour as GNU grep.
277    7.  A pattern that could match an empty string could cause pcregrep to loop; it
278        doesn't make sense to accept an empty string match in pcregrep, so I have
279        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
280        seems to be how GNU grep behaves.
282    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
283        start or after a newline", because the conditional assertion was not being
284        correctly handled. The rule now is that both the assertion and what follows
285        in the first alternative must satisfy the test.
287    9.  If auto-callout was enabled in a pattern with a conditional group whose
288        condition was an assertion, PCRE could crash during matching, both with
289        pcre_exec() and pcre_dfa_exec().
291    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
292        used for matching.
294    11. Unicode property support in character classes was not working for
295        characters (bytes) greater than 127 when not in UTF-8 mode.
297    12. Added the -M command line option to pcretest.
299    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
301    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
303    16. Added comments and documentation about mis-use of no_arg in the C++
304        wrapper.
306    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
307        from Martin Jerabek that uses macro names for all relevant character and
308        string constants.
310    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
311        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
312        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
313        these, but not everybody uses configure.
315    19. A conditional group that had only one branch was not being correctly
316        recognized as an item that could match an empty string. This meant that an
317        enclosing group might also not be so recognized, causing infinite looping
318        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
319        with the subject "ab", where knowledge that the repeated group can match
320        nothing is needed in order to break the loop.
322    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
323        exec(), but without supplying a callout function, matching went wrong.
325    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
326        leak if the size of the offset vector was greater than 30. When the vector
327        is smaller, the saved offsets during recursion go onto a local stack
328        vector, but for larger vectors malloc() is used. It was failing to free
329        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
330        error, in fact).
332    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
333        heapframe that is used only when UTF-8 support is enabled. This caused no
334        problem, but was untidy.
336    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
337        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
338        included within another project.
340    24. Steven Van Ingelgem's patches to add more options to the CMake support,
341        slightly modified by me:
343          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
344              not building pcregrep.
346          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
347              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
349    25. Forward references, both numeric and by name, in patterns that made use of
350        duplicate group numbers, could behave incorrectly or give incorrect errors,
351        because when scanning forward to find the reference group, PCRE was not
352        taking into account the duplicate group numbers. A pattern such as
353        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
355    26. Changed a few more instances of "const unsigned char *" to USPTR, making
356        the feature of a custom pointer more persuasive (as requested by a user).
358    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
359        pcretest.c, inside #ifndefs, because it seems they are sometimes already
360        pre-defined.
362    28. Added support for (*UTF8) at the start of a pattern.
364    29. Arrange for flags added by the "release type" setting in CMake to be shown
365        in the configuration summary.
368    Version 7.8 05-Sep-08
369    ---------------------
371    1.  Replaced UCP searching code with optimized version as implemented for Ad
372        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
373        stage table and inline lookup instead of a function, giving speed ups of 2
374        to 5 times on some simple patterns that I tested. Permission was given to
375        distribute the MultiStage2.py script that generates the tables (it's not in
376        the tarball, but is in the Subversion repository).
378    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
379        scripts.
381    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
382        a group with a zero qualifier. The result of the study could be incorrect,
383        or the function might crash, depending on the pattern.
385    4.  Caseless matching was not working for non-ASCII characters in back
386        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
387        It now works when Unicode Property Support is available.
389    5.  In pcretest, an escape such as \x{de} in the data was always generating
390        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
391        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
392        truncation.
394    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
396    7.  Added two (int) casts to pcregrep when printing the difference of two
397        pointers, in case they are 64-bit values.
399    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
400        test 2 if it fails.
402    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
403        and a #define of that name to empty if it is not externally set. This is to
404        allow users of MSVC to set it if necessary.
406    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
407        the convenience functions in the pcre_get.c source file.
409    11. An option change at the start of a pattern that had top-level alternatives
410        could cause overwriting and/or a crash. This command provoked a crash in
411        some environments:
413          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
415        This potential security problem was recorded as CVE-2008-2371.
417    12. For a pattern where the match had to start at the beginning or immediately
418        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
419        pcre_dfa_exec() could read past the end of the passed subject if there was
420        no match. To help with detecting such bugs (e.g. with valgrind), I modified
421        pcretest so that it places the subject at the end of its malloc-ed buffer.
423    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
424        exec() might read past the end of the data buffer in UTF-8 mode.
426    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
427        the data contained the byte 0x85 as part of a UTF-8 character within its
428        first line. This applied both to normal and DFA matching.
430    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
431        /^[^d]*?$/8 failed to match "abc".
433    16. Added a missing copyright notice to pcrecpp_internal.h.
435    17. Make it more clear in the documentation that values returned from
436        pcre_exec() in ovector are byte offsets, not character counts.
438    18. Tidied a few places to stop certain compilers from issuing warnings.
440    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
441        supplied by Stefan Weber. I made a further small update for 7.8 because
442        there is a change of source arrangements: the pcre_searchfuncs.c module is
443        replaced by pcre_ucd.c.
446    Version 7.7 07-May-08
447    ---------------------
449    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
450        a string to a long long, pretend we don't even have a long long." This is
451        done by checking for the strtoq, strtoll, and _strtoi64 functions.
453    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
454        pre-7.6 versions, which defined a global no_arg variable instead of putting
455        it in the RE class. (See also #8 below.)
457    3.  Remove a line of dead code, identified by coverity and reported by Nuno
458        Lopes.
460    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
462        (1) The include/exclude patterns were being applied to the whole pathnames
463            of files, instead of just to the final components.
465        (2) If there was more than one level of directory, the subdirectories were
466            skipped unless they satisfied the include/exclude conditions. This is
467            inconsistent with GNU grep (and could even be seen as contrary to the
468            pcregrep specification - which I improved to make it absolutely clear).
469            The action now is always to scan all levels of directory, and just
470            apply the include/exclude patterns to regular files.
472    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
473        --exclude_dir in the tests to avoid scanning .svn directories.
475    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
476        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
477        doesn't support NULs in patterns.
479    7.  Added some missing "const"s to declarations of static tables in
480        pcre_compile.c and pcre_dfa_exec.c.
482    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
483        caused by fix #2  above. (Subsequently also a second patch to fix the
484        first patch. And a third patch - this was a messy problem.)
486    9.  Applied Craig's patch to remove the use of push_back().
488    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
489        matching function regexec().
491    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
492        which, however, unlike Perl's \g{...}, are subroutine calls, not back
493        references. PCRE supports relative numbers with this syntax (I don't think
494        Oniguruma does).
496    12. Previously, a group with a zero repeat such as (...){0} was completely
497        omitted from the compiled regex. However, this means that if the group
498        was called as a subroutine from elsewhere in the pattern, things went wrong
499        (an internal error was given). Such groups are now left in the compiled
500        pattern, with a new opcode that causes them to be skipped at execution
501        time.
503    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
504        to the way PCRE behaves:
506        (a) A lone ] character is dis-allowed (Perl treats it as data).
508        (b) A back reference to an unmatched subpattern matches an empty string
509            (Perl fails the current match path).
511        (c) A data ] in a character class must be notated as \] because if the
512            first data character in a class is ], it defines an empty class. (In
513            Perl it is not possible to have an empty class.) The empty class []
514            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
515            The negative empty class [^] matches any one character, independently
516            of the DOTALL setting.
518    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
519        non-existent subpattern following a character class starting with ']' and
520        containing () gave an internal compiling error instead of "reference to
521        non-existent subpattern". Fortunately, when the pattern did exist, the
522        compiled code was correct. (When scanning forwards to check for the
523        existencd of the subpattern, it was treating the data ']' as terminating
524        the class, so got the count wrong. When actually compiling, the reference
525        was subsequently set up correctly.)
527    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
528        it was being rejected as not supported by pcre_dfa_exec(), even though
529        other assertions are supported. I have made pcre_dfa_exec() support
530        (*FAIL).
532    16. The implementation of 13c above involved the invention of a new opcode,
533        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
534        cannot be changed at match time, I realized I could make a small
535        improvement to matching performance by compiling OP_ALLANY instead of
536        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
537        on the OP_ANY path.
539    17. Compiling pcretest on Windows with readline support failed without the
540        following two fixes: (1) Make the unistd.h include conditional on
541        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
543    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
544        ncurses library to be included for pcretest when ReadLine support is
545        requested, but also to allow for it to be overridden. This patch came from
546        Daniel Bergström.
548    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
549        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
550        any errors with the current Unicode tables. Thanks to Peter Kankowski for
551        spotting this.
554    Version 7.6 28-Jan-08
555    ---------------------
557    1.  A character class containing a very large number of characters with
558        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
559        overflow.
561    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
562        HAVE_LONG_LONG is not defined.
564    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
565        bring them up to date and include new features. This patch includes:
567        - Fixed PH's badly added libz and libbz2 support.
568        - Fixed a problem with static linking.
569        - Added pcredemo. [But later removed - see 7 below.]
570        - Fixed dftables problem and added an option.
571        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
572            HAVE_LONG_LONG.
573        - Added readline support for pcretest.
574        - Added an listing of the option settings after cmake has run.
576    4.  A user submitted a patch to Makefile that makes it easy to create
577        "pcre.dll" under mingw when using Configure/Make. I added stuff to
578        Makefile.am that cause it to include this special target, without
579        affecting anything else. Note that the same mingw target plus all
580        the other distribution libraries and programs are now supported
581        when configuring with CMake (see 6 below) instead of with
582        Configure/Make.
584    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
585        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
586        exported in the Windows port". It has not yet been confirmed that the patch
587        solves the problem, but it does no harm.
589    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
590        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
591        with CMake, and also correct the comment about stack recursion.
593    7.  Remove the automatic building of pcredemo from the ./configure system and
594        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
595        of a program that users should build themselves after PCRE is installed, so
596        building it automatically is not really right. What is more, it gave
597        trouble in some build environments.
599    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
602    Version 7.5 10-Jan-08
603    ---------------------
605    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
606        values in parens when parsing an RE using the C++ wrapper."
608    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
609        Characters greater than 255 were excluded from the class instead of being
610        included.
612    3.  The same bug as (2) above applied to negated POSIX classes such as
613        [:^space:].
615    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
616        defined or documented. It seems to have been a typo for PCRE_STATIC, so
617        I have changed it.
619    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
620        first named subpattern) and a construct such as (?&a) would reference the
621        first named subpattern whose name started with "a" (in other words, the
622        length check was missing). Both these problems are fixed. "Subpattern name
623        expected" is now given for (?&) (a zero-length name), and this patch also
624        makes it give the same error for \k'' (previously it complained that that
625        was a reference to a non-existent subpattern).
627    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
628        this is right because (?- can be followed by option settings as well as by
629        digits. I have, however, made the messages clearer.
631    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
632        than the number used in the conditional) now cause a compile-time error.
633        This is actually not compatible with Perl, which accepts such patterns, but
634        treats the conditional as always being FALSE (as PCRE used to), but it
635        seems to me that giving a diagnostic is better.
637    8.  Change "alphameric" to the more common word "alphanumeric" in comments
638        and messages.
640    9.  Fix two occurrences of "backslash" in comments that should have been
641        "backspace".
643    10. Remove two redundant lines of code that can never be obeyed (their function
644        was moved elsewhere).
646    11. The program that makes PCRE's Unicode character property table had a bug
647        which caused it to generate incorrect table entries for sequences of
648        characters that have the same character type, but are in different scripts.
649        It amalgamated them into a single range, with the script of the first of
650        them. In other words, some characters were in the wrong script. There were
651        thirteen such cases, affecting characters in the following ranges:
653          U+002b0 - U+002c1
654          U+0060c - U+0060d
655          U+0061e - U+00612
656          U+0064b - U+0065e
657          U+0074d - U+0076d
658          U+01800 - U+01805
659          U+01d00 - U+01d77
660          U+01d9b - U+01dbf
661          U+0200b - U+0200f
662          U+030fc - U+030fe
663          U+03260 - U+0327f
664          U+0fb46 - U+0fbb1
665          U+10450 - U+1049d
667    12. The -o option (show only the matching part of a line) for pcregrep was not
668        compatible with GNU grep in that, if there was more than one match in a
669        line, it showed only the first of them. It now behaves in the same way as
670        GNU grep.
672    13. If the -o and -v options were combined for pcregrep, it printed a blank
673        line for every non-matching line. GNU grep prints nothing, and pcregrep now
674        does the same. The return code can be used to tell if there were any
675        non-matching lines.
677    14. Added --file-offsets and --line-offsets to pcregrep.
679    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
680        infinitely looping recursion. The bug was that positive lookaheads were not
681        being skipped when checking for a possible empty match (negative lookaheads
682        and both kinds of lookbehind were skipped).
684    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
685        inclusion of <windows.h> to before rather than after the definition of
686        INVALID_FILE_ATTRIBUTES (patch from David Byron).
688    17. Specifying a possessive quantifier with a specific limit for a Unicode
689        character property caused pcre_compile() to compile bad code, which led at
690        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
691        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
692        caused the error; without that there was no problem.
694    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
696    19. Added --enable-pcretest-libreadline.
698    20. In pcrecpp.cc, the variable 'count' was incremented twice in
699        RE::GlobalReplace(). As a result, the number of replacements returned was
700        double what it should be. I removed one of the increments, but Craig sent a
701        later patch that removed the other one (the right fix) and added unit tests
702        that check the return values (which was not done before).
704    21. Several CMake things:
706        (1) Arranged that, when cmake is used on Unix, the libraries end up with
707            the names libpcre and libpcreposix, not just pcre and pcreposix.
709        (2) The above change means that pcretest and pcregrep are now correctly
710            linked with the newly-built libraries, not previously installed ones.
714    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
715        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
716        UTF-8 newline character). The key issue is that the pattern starts .*;
717        this means that the match must be either at the beginning, or after a
718        newline. The bug was in the code for advancing after a failed match and
719        checking that the new position followed a newline. It was not taking
720        account of UTF-8 characters correctly.
722    23. PCRE was behaving differently from Perl in the way it recognized POSIX
723        character classes. PCRE was not treating the sequence [:...:] as a
724        character class unless the ... were all letters. Perl, however, seems to
725        allow any characters between [: and :], though of course it rejects as
726        unknown any "names" that contain non-letters, because all the known class
727        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
728        for example, whereas PCRE did not - it did not recognize a POSIX character
729        class. This seemed a bit dangerous, so the code has been changed to be
730        closer to Perl. The behaviour is not identical to Perl, because PCRE will
731        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
732        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
733        Perl does, and where it didn't before.
735    24. Rewrite so as to remove the single use of %n from pcregrep because in some
736        Windows environments %n is disabled by default.
739    Version 7.4 21-Sep-07
740    ---------------------
742    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
743        means that a class such as [\s] counted as "explicit reference to CR or
744        LF". That isn't really right - the whole point of the change was to try to
745        help when there was an actual mention of one of the two characters. So now
746        the change happens only if \r or \n (or a literal CR or LF) character is
747        encountered.
749    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
750        of both had grown to the point where there were only 3 bits left.
751        Fortunately, there was spare space in the data structure, and so I have
752        moved the internal flags into a new 16-bit field to free up more option
753        bits.
755    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
756        but did not set the internal JCHANGED flag - either of these is enough to
757        control the way the "get" function works - but the PCRE_INFO_JCHANGED
758        facility is supposed to tell if (?J) was ever used, so now (?J) at the
759        start sets both bits.
761    4.  Added options (at build time, compile time, exec time) to change \R from
762        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
764    5.  doc/pcresyntax.html was missing from the distribution.
766    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
767        compatibility, even though it is no longer used.
769    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
770        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
771        windows.h file is present (where different names are used). [This was
772        reversed later after testing - see 16 below.]
774    8.  Changed all #include <config.h> to #include "config.h". There were also
775        some further <pcre.h> cases that I changed to "pcre.h".
777    9.  When pcregrep was used with the --colour option, it missed the line ending
778        sequence off the lines that it output.
780    10. It was pointed out to me that arrays of string pointers cause lots of
781        relocations when a shared library is dynamically loaded. A technique of
782        using a single long string with a table of offsets can drastically reduce
783        these. I have refactored PCRE in four places to do this. The result is
784        dramatic:
786          Originally:                          290
787          After changing UCP table:            187
788          After changing error message table:   43
789          After changing table of "verbs"       36
790          After changing table of Posix names   22
792        Thanks to the folks working on Gregex for glib for this insight.
794    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
795        unicode-properties was also set.
797    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
799    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
800        checked only for CRLF.
802    14. Added casts to pcretest.c to avoid compiler warnings.
804    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
806    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
807        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
808        entirely. This removes changes made in 7 above.
810    17. The CMake files have been updated, and there is now more information about
811        building with CMake in the NON-UNIX-USE document.
814    Version 7.3 28-Aug-07
815    ---------------------
817     1. In the rejigging of the build system that eventually resulted in 7.1, the
818        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
819        brackets there is not right, since it causes compilers to look for an
820        installed pcre.h, not the version that is in the source that is being
821        compiled (which of course may be different). I have changed it back to:
823          #include "pcre.h"
825        I have a vague recollection that the change was concerned with compiling in
826        different directories, but in the new build system, that is taken care of
827        by the VPATH setting the Makefile.
829     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
830        when the subject happened to end in the byte 0x85 (e.g. if the last
831        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
832        characters but of course it shouldn't be taken as a newline when it is part
833        of another character. The bug was that, for an unlimited repeat of . in
834        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
835        characters when looking for a newline.
837     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
839     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
840        in debug output.
842     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
843        long printing in the pcrecpp unittest when running under MinGW.
845     6. ESC_K was left out of the EBCDIC table.
847     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
848        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
849        limit also applies to "virtual nesting" when a pattern is recursive, and in
850        this case 1000 isn't so big. I have been able to remove this limit at the
851        expense of backing off one optimization in certain circumstances. Normally,
852        when pcre_exec() would call its internal match() function recursively and
853        immediately return the result unconditionally, it uses a "tail recursion"
854        feature to save stack. However, when a subpattern that can match an empty
855        string has an unlimited repetition quantifier, it no longer makes this
856        optimization. That gives it a stack frame in which to save the data for
857        checking that an empty string has been matched. Previously this was taken
858        from the 1000-entry workspace that had been reserved. So now there is no
859        explicit limit, but more stack is used.
861     8. Applied Daniel's patches to solve problems with the import/export magic
862        syntax that is required for Windows, and which was going wrong for the
863        pcreposix and pcrecpp parts of the library. These were overlooked when this
864        problem was solved for the main library.
866     9. There were some crude static tests to avoid integer overflow when computing
867        the size of patterns that contain repeated groups with explicit upper
868        limits. As the maximum quantifier is 65535, the maximum group length was
869        set at 30,000 so that the product of these two numbers did not overflow a
870        32-bit integer. However, it turns out that people want to use groups that
871        are longer than 30,000 bytes (though not repeat them that many times).
872        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
873        made it possible to implement the integer overflow checks in a much more
874        dynamic way, which I have now done. The artificial limitation on group
875        length has been removed - we now have only the limit on the total length of
876        the compiled pattern, which depends on the LINK_SIZE setting.
878    10. Fixed a bug in the documentation for get/copy named substring when
879        duplicate names are permitted. If none of the named substrings are set, the
880        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
881        empty string.
883    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
884        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
885        because the ] is interpreted as the first data character and the
886        terminating ] is not found. PCRE has been made compatible with Perl in this
887        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
888        cause memory overwriting.
890    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
891        string has been matched (to stop an infinite loop). It was not recognizing
892        a conditional subpattern that could match an empty string if that
893        subpattern was within another subpattern. For example, it looped when
894        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
895        condition was not nested. This bug has been fixed.
897    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
898        past the start of the subject in the presence of bytes with the top bit
899        set, for example "\x8aBCD".
901    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
902        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
904    14. Optimized (?!) to (*FAIL).
906    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
907        This restricts code points to be within the range 0 to 0x10FFFF, excluding
908        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
909        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
910        does: it's just the validity check that is more restrictive.
912    16. Inserted checks for integer overflows during escape sequence (backslash)
913        processing, and also fixed erroneous offset values for syntax errors during
914        backslash processing.
916    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
917        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
919    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
920        caused an overrun.
922    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
923        something other than just ASCII characters) inside a group that had an
924        unlimited repeat caused a loop at compile time (while checking to see
925        whether the group could match an empty string).
927    20. Debugging a pattern containing \p or \P could cause a crash. For example,
928        [\P{Any}] did so. (Error in the code for printing property names.)
930    21. An orphan \E inside a character class could cause a crash.
932    22. A repeated capturing bracket such as (A)? could cause a wild memory
933        reference during compilation.
935    23. There are several functions in pcre_compile() that scan along a compiled
936        expression for various reasons (e.g. to see if it's fixed length for look
937        behind). There were bugs in these functions when a repeated \p or \P was
938        present in the pattern. These operators have additional parameters compared
939        with \d, etc, and these were not being taken into account when moving along
940        the compiled data. Specifically:
942        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
943            length.
945        (b) An item such as \pL+ within a repeated group could cause crashes or
946            loops.
948        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
949            "reference to non-existent subpattern" error.
951        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
953    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
954        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
956    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
958    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
959        character were causing crashes (broken optimization).
961    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
962        \p or \P) caused a compile-time loop.
964    28. More problems have arisen in unanchored patterns when CRLF is a valid line
965        break. For example, the unstudied pattern [\r\n]A does not match the string
966        "\r\nA" because change 7.0/46 below moves the current point on by two
967        characters after failing to match at the start. However, the pattern \nA
968        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
969        the same is true. There doesn't seem any very clean way out of this, but
970        what I have chosen to do makes the common cases work: PCRE now takes note
971        of whether there can be an explicit match for \r or \n anywhere in the
972        pattern, and if so, 7.0/46 no longer applies. As part of this change,
973        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
974        pattern has explicit CR or LF references.
976    29. Added (*CR) etc for changing newline setting at start of pattern.
979    Version 7.2 19-Jun-07
980    ---------------------
982     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
983        which is apparently normally available under Windows.
985     2. Re-jig the pcregrep tests with different newline settings in an attempt
986        to make them independent of the local environment's newline setting.
988     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
990     4. Some of the "internals" tests were previously cut out when the link size
991        was not 2, because the output contained actual offsets. The recent new
992        "Z" feature of pcretest means that these can be cut out, making the tests
993        usable with all link sizes.
995     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
996        stack recursion. This gives a massive performance boost under BSD, but just
997        a small improvement under Linux. However, it saves one field in the frame
998        in all cases.
1000     6. Added more features from the forthcoming Perl 5.10:
1002        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1003            recursion call. It refers to the nth most recently opened parentheses.
1005        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1006            to be opened parentheses.
1008        (c) Conditions that refer to capturing parentheses can be specified
1009            relatively, for example, (?(-2)... or (?(+3)...
1011        (d) \K resets the start of the current match so that everything before
1012            is not part of it.
1014        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1016        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1017            reference syntax.
1019        (g) (?| introduces a group in which the numbering of parentheses in each
1020            alternative starts with the same number.
1022        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1024     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1027     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1028        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1029        for detecting groups that can match an empty string.
1031     9. A pattern with a very large number of alternatives (more than several
1032        hundred) was running out of internal workspace during the pre-compile
1033        phase, where pcre_compile() figures out how much memory will be needed. A
1034        bit of new cunning has reduced the workspace needed for groups with
1035        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1036        workspace instead of running out of the 4096 that are available.
1038    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1040    11. Applied patch from Google to remove an optimization that didn't quite work.
1041        The report of the bug said:
1043          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1044          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1045          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1047    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1048        it matched the wrong number of bytes.
1051    Version 7.1 24-Apr-07
1052    ---------------------
1054     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1055        that is more "standard", making use of automake and other Autotools. There
1056        is some re-arrangement of the files and adjustment of comments consequent
1057        on this.
1059     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1060        for recursive directory scanning broke on some systems because the files
1061        are not scanned in any specific order and on different systems the order
1062        was different. A call to "sort" has been inserted into RunGrepTest for the
1063        approprate test as a short-term fix. In the longer term there may be an
1064        alternative.
1066     3. I had an email from Eric Raymond about problems translating some of PCRE's
1067        man pages to HTML (despite the fact that I distribute HTML pages, some
1068        people do their own conversions for various reasons). The problems
1069        concerned the use of low-level troff macros .br and .in. I have therefore
1070        removed all such uses from the man pages (some were redundant, some could
1071        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1072        HTML has been updated to handle .nf/.fi and to complain if it encounters
1073        .br or .in.
1075     4. Updated comments in configure.ac that get placed in config.h.in and also
1076        arranged for config.h to be included in the distribution, with the name
1077        config.h.generic, for the benefit of those who have to compile without
1078        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1080     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1081        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1082        makevp.bat for the current PCRE, using the additional files
1083        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1085     6. A Windows user reported a minor discrepancy with test 2, which turned out
1086        to be caused by a trailing space on an input line that had got lost in his
1087        copy. The trailing space was an accident, so I've just removed it.
1089     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1090        that is needed.
1092     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1093        as "const" (a) because they are and (b) because it helps the PHP
1094        maintainers who have recently made a script to detect big data structures
1095        in the php code that should be moved to the .rodata section. I remembered
1096        to update Builducptable as well, so it won't revert if ucptable.h is ever
1097        re-created.
1099     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1100        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1101        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1102        support is not required. This saves 1.5-2K of code, which is important in
1103        some applications.
1105        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1106        so as not to refer to the tables, even though these functions will never be
1107        called when UTF-8 support is disabled. Otherwise there are problems with a
1108        shared library.
1110    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1112        (a) It was defining its arguments as char * instead of void *.
1114        (b) It was assuming that all moves were upwards in memory; this was true
1115            a long time ago when I wrote it, but is no longer the case.
1117        The emulated memove() is provided for those environments that have neither
1118        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1119        is clearly not the case, as these two bugs were recently reported.
1121    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1122        and Detrail to create the HTML documentation, the .txt form of the man
1123        pages, and it removes trailing spaces from listed files. It also creates
1124        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1125        case, it wraps all the #defines with #ifndefs. This script should be run
1126        before "make dist".
1128    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1129        with Unicode property support.
1131        (a) For a maximizing quantifier, if the two different cases of the
1132            character were of different lengths in their UTF-8 codings (there are
1133            some cases like this - I found 11), and the matching function had to
1134            back up over a mixture of the two cases, it incorrectly assumed they
1135            were both the same length.
1137        (b) When PCRE was configured to use the heap rather than the stack for
1138            recursion during matching, it was not correctly preserving the data for
1139            the other case of a UTF-8 character when checking ahead for a match
1140            while processing a minimizing repeat. If the check also involved
1141            matching a wide character, but failed, corruption could cause an
1142            erroneous result when trying to check for a repeat of the original
1143            character.
1145    13. Some tidying changes to the testing mechanism:
1147        (a) The RunTest script now detects the internal link size and whether there
1148            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1149            values substituted by "configure". (The RunGrepTest script already did
1150            this for UTF-8.) The configure.ac script no longer substitutes the
1151            relevant variables.
1153        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1154            with length and offset values. This means that the output is different
1155            for different internal link sizes. Test 2 is skipped for link sizes
1156            other than 2 because of this, bypassing the problem. Unfortunately,
1157            there was also a test in test 3 (the locale tests) that used /B and
1158            failed for link sizes other than 2. Rather than cut the whole test out,
1159            I have added a new /Z option to pcretest that replaces the length and
1160            offset values with spaces. This is now used to make test 3 independent
1161            of link size. (Test 2 will be tidied up later.)
1163    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1164        segmentation fault instead of returning the appropriate error message.
1166    15. In multiline mode when the newline sequence was set to "any", the pattern
1167        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1168        This doesn't seem right; it now treats the CRLF combination as the line
1169        ending, and so does not match in that case. It's only a pattern such as ^$
1170        that would hit this one: something like ^ABC$ would have failed after \r
1171        and then tried again after \r\n.
1173    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1174        in an attempt to make files that differ only in their line terminators
1175        compare equal. This works on Linux.
1177    17. Under certain error circumstances pcregrep might try to free random memory
1178        as it exited. This is now fixed, thanks to valgrind.
1180    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1181        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1182        was because its rules for how to advance for /g after matching an empty
1183        string at the end of a line did not allow for this case. They now check for
1184        it specially.
1186    20. pcretest is supposed to handle patterns and data of any length, by
1187        extending its buffers when necessary. It was getting this wrong when the
1188        buffer for a data line had to be extended.
1190    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1191        CRLF as a newline sequence.
1193    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1194        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1195        I have nevertheless tidied it up.
1197    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1199    24. Added a man page for pcre-config.
1202    Version 7.0 19-Dec-06
1203    ---------------------
1205     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1206        moving to gcc 4.1.1.
1208     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1209        sys/time.h, which is documented as needed for this function. It doesn't
1210        seem to matter on Linux, but it showed up on some releases of OS X.
1212     3. It seems that there are systems where bytes whose values are greater than
1213        127 match isprint() in the "C" locale. The "C" locale should be the
1214        default when a C program starts up. In most systems, only ASCII printing
1215        characters match isprint(). This difference caused the output from pcretest
1216        to vary, making some of the tests fail. I have changed pcretest so that:
1218        (a) When it is outputting text in the compiled version of a pattern, bytes
1219            other than 32-126 are always shown as hex escapes.
1221        (b) When it is outputting text that is a matched part of a subject string,
1222            it does the same, unless a different locale has been set for the match
1223            (using the /L modifier). In this case, it uses isprint() to decide.
1225     4. Fixed a major bug that caused incorrect computation of the amount of memory
1226        required for a compiled pattern when options that changed within the
1227        pattern affected the logic of the preliminary scan that determines the
1228        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1229        that the computed length was too small. The symptoms of this bug were
1230        either the PCRE error "internal error: code overflow" from pcre_compile(),
1231        or a glibc crash with a message such as "pcretest: free(): invalid next
1232        size (fast)". Examples of patterns that provoked this bug (shown in
1233        pcretest format) are:
1235          /(?-x: )/x
1236          /(?x)(?-x: \s*#\s*)/
1237          /((?i)[\x{c0}])/8
1238          /(?i:[\x{c0}])/8
1240        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1241        is now done differently.
1243     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1244        wrapper classes; (b) implement a new function in the C++ scanner that is
1245        more efficient than the old way of doing things because it avoids levels of
1246        recursion in the regex matching; (c) add a paragraph to the documentation
1247        for the FullMatch() function.
1249     6. The escape sequence \n was being treated as whatever was defined as
1250        "newline". Not only was this contrary to the documentation, which states
1251        that \n is character 10 (hex 0A), but it also went horribly wrong when
1252        "newline" was defined as CRLF. This has been fixed.
1254     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1255        was being set to -1 for the "end of line" case (supposedly a value that no
1256        character can have). Though this value is never used (the check for end of
1257        line is "zero bytes in current character"), it caused compiler complaints.
1258        I've changed it to 0xffffffff.
1260     8. In pcre_version.c, the version string was being built by a sequence of
1261        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1262        string (as it is for production releases) called a macro with an empty
1263        argument. The C standard says the result of this is undefined. The gcc
1264        compiler treats it as an empty string (which was what was wanted) but it is
1265        reported that Visual C gives an error. The source has been hacked around to
1266        avoid this problem.
1268     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1269        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1270        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1271        of them did).
1273    10. Originally, pcretest opened its input and output without "b"; then I was
1274        told that "b" was needed in some environments, so it was added for release
1275        5.0 to both the input and output. (It makes no difference on Unix-like
1276        systems.) Later I was told that it is wrong for the input on Windows. I've
1277        now abstracted the modes into two macros, to make it easier to fiddle with
1278        them, and removed "b" from the input mode under Windows.
1280    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1282    12. Added -help and --help to pcretest as an official way of being reminded
1283        of the options.
1285    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1286        and pcrecpp.cc because they annoy compilers at high warning levels.
1288    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1290    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1291        scripts are not C programs :-) and which was not noticed because it works
1292        on Linux.
1294    16. pcretest is supposed to handle any length of pattern and data line (as one
1295        line or as a continued sequence of lines) by extending its input buffer if
1296        necessary. This feature was broken for very long pattern lines, leading to
1297        a string of junk being passed to pcre_compile() if the pattern was longer
1298        than about 50K.
1300    17. I have done a major re-factoring of the way pcre_compile() computes the
1301        amount of memory needed for a compiled pattern. Previously, there was code
1302        that made a preliminary scan of the pattern in order to do this. That was
1303        OK when PCRE was new, but as the facilities have expanded, it has become
1304        harder and harder to keep it in step with the real compile phase, and there
1305        have been a number of bugs (see for example, 4 above). I have now found a
1306        cunning way of running the real compile function in a "fake" mode that
1307        enables it to compute how much memory it would need, while actually only
1308        ever using a few hundred bytes of working memory and without too many
1309        tests of the mode. This should make future maintenance and development
1310        easier. A side effect of this work is that the limit of 200 on the nesting
1311        depth of parentheses has been removed (though this was never a serious
1312        limitation, I suspect). However, there is a downside: pcre_compile() now
1313        runs more slowly than before (30% or more, depending on the pattern). I
1314        hope this isn't a big issue. There is no effect on runtime performance.
1316    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1317        newline (only possible for the last line of a file) and it was a
1318        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1320    19. Added additional timing features to pcretest. (1) The -tm option now times
1321        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1322        separate command line item, by a number that specifies the number of
1323        repeats to use when timing. The default is 50000; this gives better
1324        precision, but takes uncomfortably long for very large patterns.
1326    20. Extended pcre_study() to be more clever in cases where a branch of a
1327        subpattern has no definite first character. For example, (a*|b*)[cd] would
1328        previously give no result from pcre_study(). Now it recognizes that the
1329        first character must be a, b, c, or d.
1331    21. There was an incorrect error "recursive call could loop indefinitely" if
1332        a subpattern (or the entire pattern) that was being tested for matching an
1333        empty string contained only one non-empty item after a nested subpattern.
1334        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1335        incorrectly, because the \d was being skipped in the check.
1337    22. The pcretest program now has a new pattern option /B and a command line
1338        option -b, which is equivalent to adding /B to every pattern. This causes
1339        it to show the compiled bytecode, without the additional information that
1340        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1341        is the same as /B/I).
1343    23. A new optimization is now able automatically to treat some sequences such
1344        as a*b as a*+b. More specifically, if something simple (such as a character
1345        or a simple class like \d) has an unlimited quantifier, and is followed by
1346        something that cannot possibly match the quantified thing, the quantifier
1347        is automatically "possessified".
1349    24. A recursive reference to a subpattern whose number was greater than 39
1350        went wrong under certain circumstances in UTF-8 mode. This bug could also
1351        have affected the operation of pcre_study().
1353    25. Realized that a little bit of performance could be had by replacing
1354        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1356    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1358    27. Possessive quantifiers such as a++ were previously implemented by turning
1359        them into atomic groups such as ($>a+). Now they have their own opcodes,
1360        which improves performance. This includes the automatically created ones
1361        from 23 above.
1363    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1364        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1365        the first matched character to be a colon. This applied both to named and
1366        numbered groups.
1368    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1370    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1371        building PCRE on Windows easier, so I have included it in the distribution.
1373    31. There is now a check in pcretest against a ridiculously large number being
1374        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1375        loop, the loop is abandoned.
1377    32. Forward references to subpatterns in conditions such as (?(2)...) where
1378        subpattern 2 is defined later cause pcre_compile() to search forwards in
1379        the pattern for the relevant set of parentheses. This search went wrong
1380        when there were unescaped parentheses in a character class, parentheses
1381        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1383    33. "Subroutine" calls and backreferences were previously restricted to
1384        referencing subpatterns earlier in the regex. This restriction has now
1385        been removed.
1387    34. Added a number of extra features that are going to be in Perl 5.10. On the
1388        whole, these are just syntactic alternatives for features that PCRE had
1389        previously implemented using the Python syntax or my own invention. The
1390        other formats are all retained for compatibility.
1392        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1393            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1394            also .NET compatible.
1396        (b) A recursion or subroutine call to a named group can now be defined as
1397            (?&name) as well as (?P>name).
1399        (c) A backreference to a named group can now be defined as \k<name> or
1400            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1401            5.10, are also .NET compatible.
1403        (d) A conditional reference to a named group can now use the syntax
1404            (?(<name>) or (?('name') as well as (?(name).
1406        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1407            groups (named and numbered) that are never evaluated inline, but can be
1408            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1409            is always false. There may be only one alternative in such a group.
1411        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1412            as the simple (?(R). The condition is true only if the most recent
1413            recursion is that of the given number or name. It does not search out
1414            through the entire recursion stack.
1416        (g) The escape \gN or \g{N} has been added, where N is a positive or
1417            negative number, specifying an absolute or relative reference.
1419    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1420        some "unreachable code" warnings.
1422    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1423        things, this adds five new scripts.
1425    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1426        There were also incompatibilities regarding the handling of \Q..\E inside
1427        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1428        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1430    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1431        matches an empty string, and forcibly breaks the loop. There were bugs in
1432        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1433        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1434        separate and independent bugs (that affected different cases) have been
1435        fixed.
1437    39. Refactored the code to abolish the use of different opcodes for small
1438        capturing bracket numbers. This is a tidy that I avoided doing when I
1439        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1440        The new approach is not only tidier, it makes it possible to reduce the
1441        memory needed to fix the previous bug (38).
1443    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1444        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1445        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1446        mode.
1448    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1449        report.
1451    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1452        copy construction and assignment in the C++ wrapper.
1454    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1455        couple of bugs that could have given wrong results in the "--newline=crlf"
1456        case.
1458    44. Added a number of casts and did some reorganization of signed/unsigned int
1459        variables following suggestions from Dair Grant. Also renamed the variable
1460        "this" as "item" because it is a C++ keyword.
1462    45. Arranged for dftables to add
1464          #include "pcre_internal.h"
1466        to pcre_chartables.c because without it, gcc 4.x may remove the array
1467        definition from the final binary if PCRE is built into a static library and
1468        dead code stripping is activated.
1470    46. For an unanchored pattern, if a match attempt fails at the start of a
1471        newline sequence, and the newline setting is CRLF or ANY, and the next two
1472        characters are CRLF, advance by two characters instead of one.
1475    Version 6.7 04-Jul-06
1476    ---------------------
1478     1. In order to handle tests when input lines are enormously long, pcretest has
1479        been re-factored so that it automatically extends its buffers when
1480        necessary. The code is crude, but this _is_ just a test program. The
1481        default size has been increased from 32K to 50K.
1483     2. The code in pcre_study() was using the value of the re argument before
1484        testing it for NULL. (Of course, in any sensible call of the function, it
1485        won't be NULL.)
1487     3. The memmove() emulation function in pcre_internal.h, which is used on
1488        systems that lack both memmove() and bcopy() - that is, hardly ever -
1489        was missing a "static" storage class specifier.
1491     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1492        containing an extended class (one that cannot be represented by a bitmap
1493        because it contains high-valued characters or Unicode property items, e.g.
1494        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1495        pattern, but PCRE should not loop if you do not (it no longer does).
1496        [Detail: two cases were found: (a) a repeated subpattern containing an
1497        extended class; (b) a recursive reference to a subpattern that followed a
1498        previous extended class. It wasn't skipping over the extended class
1499        correctly when UTF-8 mode was not set.]
1501     5. A negated single-character class was not being recognized as fixed-length
1502        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1503        compile error "lookbehind assertion is not fixed length".
1505     6. The RunPerlTest auxiliary script was showing an unexpected difference
1506        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1507        write a Perl script that can interpret lines of an input file either as
1508        byte characters or as UTF-8, which is what "perltest" was being required to
1509        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1510        can't do is switch easily at run time between having the "use utf8;" pragma
1511        or not. In the end, I fudged it by using the RunPerlTest script to insert
1512        "use utf8;" explicitly for the UTF-8 tests.
1514     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1515        the end of the subject string, contrary to the documentation and to what
1516        Perl does. This was true of both matching functions. Now it matches only at
1517        the start of the subject and immediately after *internal* newlines.
1519     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1520        a pointer to an int instead of a pointer to an unsigned long int. This
1521        caused problems on 64-bit systems.
1523     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1524        instance of the 'standard' template library not being so standard".
1526    10. There was no check on the number of named subpatterns nor the maximum
1527        length of a subpattern name. The product of these values is used to compute
1528        the size of the memory block for a compiled pattern. By supplying a very
1529        long subpattern name and a large number of named subpatterns, the size
1530        computation could be caused to overflow. This is now prevented by limiting
1531        the length of names to 32 characters, and the number of named subpatterns
1532        to 10,000.
1534    11. Subpatterns that are repeated with specific counts have to be replicated in
1535        the compiled pattern. The size of memory for this was computed from the
1536        length of the subpattern and the repeat count. The latter is limited to
1537        65535, but there was no limit on the former, meaning that integer overflow
1538        could in principle occur. The compiled length of a repeated subpattern is
1539        now limited to 30,000 bytes in order to prevent this.
1541    12. Added the optional facility to have named substrings with the same name.
1543    13. Added the ability to use a named substring as a condition, using the
1544        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1545        are numbers (not recommended). Forward references are permitted.
1547    14. Added forward references in named backreferences (if you see what I mean).
1549    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1550        pattern could run off the end of the subject. For example, the pattern
1551        "(?s)(.{1,5})"8 did this with the subject "ab".
1553    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1554        PCRE_CASELESS was set when matching characters that were quantified with ?
1555        or *.
1557    17. A character class other than a single negated character that had a minimum
1558        but no maximum quantifier - for example [ab]{6,} - was not handled
1559        correctly by pce_dfa_exec(). It would match only one character.
1561    18. A valid (though odd) pattern that looked like a POSIX character
1562        class but used an invalid character after [ (for example [[,abc,]]) caused
1563        pcre_compile() to give the error "Failed: internal error: code overflow" or
1564        in some cases to crash with a glibc free() error. This could even happen if
1565        the pattern terminated after [[ but there just happened to be a sequence of
1566        letters, a binary zero, and a closing ] in the memory that followed.
1568    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1569        over the years. Originally (before any Unicode support), just the bottom 8
1570        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1571        output from "man perlunicode" includes this:
1573          The regular expression compiler produces polymorphic opcodes.  That
1574          is, the pattern adapts to the data and automatically switches to
1575          the Unicode character scheme when presented with Unicode data--or
1576          instead uses a traditional byte scheme when presented with byte
1577          data.
1579        Sadly, a wide octal escape does not cause a switch, and in a string with
1580        no other multibyte characters, these octal escapes are treated as before.
1581        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1582        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1583        Unicode string.
1585        I have not perpetrated such confusion in PCRE. Up till now, it took just
1586        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1587        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1588        translate to the appropriate multibyte character.
1590    29. Applied some refactoring to reduce the number of warnings from Microsoft
1591        and Borland compilers. This has included removing the fudge introduced
1592        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1593        a warning about an unused variable.
1595    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1596        characters since release 4.0, because Perl (from release 5.004) does not.
1597        [Or at least, is documented not to: some releases seem to be in conflict
1598        with the documentation.] However, when a pattern was studied with
1599        pcre_study() and all its branches started with \s, PCRE still included VT
1600        as a possible starting character. Of course, this did no harm; it just
1601        caused an unnecessary match attempt.
1603    22. Removed a now-redundant internal flag bit that recorded the fact that case
1604        dependency changed within the pattern. This was once needed for "required
1605        byte" processing, but is no longer used. This recovers a now-scarce options
1606        bit. Also moved the least significant internal flag bit to the most-
1607        significant bit of the word, which was not previously used (hangover from
1608        the days when it was an int rather than a uint) to free up another bit for
1609        the future.
1611    23. Added support for CRLF line endings as well as CR and LF. As well as the
1612        default being selectable at build time, it can now be changed at runtime
1613        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1614        specify that it is scanning data with non-default line endings.
1616    24. Changed the definition of CXXLINK to make it agree with the definition of
1617        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1619    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1620        recursions. This makes a big different to stack usage for some patterns.
1622    26. If a subpattern containing a named recursion or subroutine reference such
1623        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1624        the space required for the compiled pattern went wrong and gave too small a
1625        value. Depending on the environment, this could lead to "Failed: internal
1626        error: code overflow at offset 49" or "glibc detected double free or
1627        corruption" errors.
1629    27. Applied patches from Google (a) to support the new newline modes and (b) to
1630        advance over multibyte UTF-8 characters in GlobalReplace.
1632    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1633        difference for some implementation of PCRE in some Windows version.
1635    29. Added some extra testing facilities to pcretest:
1637        \q<number>   in a data line sets the "match limit" value
1638        \Q<number>   in a data line sets the "match recursion limt" value
1639        -S <number>  sets the stack size, where <number> is in megabytes
1641        The -S option isn't available for Windows.
1644    Version 6.6 06-Feb-06
1645    ---------------------
1647     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1648        in pcreposix.h. I have copied the definition from pcre.h.
1650     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1651        because pcre.h is no longer a built file.
1653     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1654        not normally included in the compiled code.
1657    Version 6.5 01-Feb-06
1658    ---------------------
1660     1. When using the partial match feature with pcre_dfa_exec(), it was not
1661        anchoring the second and subsequent partial matches at the new starting
1662        point. This could lead to incorrect results. For example, with the pattern
1663        /1234/, partially matching against "123" and then "a4" gave a match.
1665     2. Changes to pcregrep:
1667        (a) All non-match returns from pcre_exec() were being treated as failures
1668            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1669            error message is output. Some extra information is given for the
1670            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1671            probably the only errors that are likely to be caused by users (by
1672            specifying a regex that has nested indefinite repeats, for instance).
1673            If there are more than 20 of these errors, pcregrep is abandoned.
1675        (b) A binary zero was treated as data while matching, but terminated the
1676            output line if it was written out. This has been fixed: binary zeroes
1677            are now no different to any other data bytes.
1679        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1680            used to set a locale for matching. The --locale=xxxx long option has
1681            been added (no short equivalent) to specify a locale explicitly on the
1682            pcregrep command, overriding the environment variables.
1684        (d) When -B was used with -n, some line numbers in the output were one less
1685            than they should have been.
1687        (e) Added the -o (--only-matching) option.
1689        (f) If -A or -C was used with -c (count only), some lines of context were
1690            accidentally printed for the final match.
1692        (g) Added the -H (--with-filename) option.
1694        (h) The combination of options -rh failed to suppress file names for files
1695            that were found from directory arguments.
1697        (i) Added the -D (--devices) and -d (--directories) options.
1699        (j) Added the -F (--fixed-strings) option.
1701        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1703        (l) Added the --colo(u)r option.
1705        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1706            is not present by default.
1708     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1709        items such as (?R) or (?1), when the recursion could match a number of
1710        alternatives. If it matched one of the alternatives, but subsequently,
1711        outside the recursion, there was a failure, the code tried to back up into
1712        the recursion. However, because of the way PCRE is implemented, this is not
1713        possible, and the result was an incorrect result from the match.
1715        In order to prevent this happening, the specification of recursion has
1716        been changed so that all such subpatterns are automatically treated as
1717        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1719     4. I had overlooked the fact that, in some locales, there are characters for
1720        which isalpha() is true but neither isupper() nor islower() are true. In
1721        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1722        and ordfeminine) are like this. This affected the treatment of \w and \W
1723        when they appeared in character classes, but not when they appeared outside
1724        a character class. The bit map for "word" characters is now created
1725        separately from the results of isalnum() instead of just taking it from the
1726        upper, lower, and digit maps. (Plus the underscore character, of course.)
1728     5. The above bug also affected the handling of POSIX character classes such as
1729        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1730        permanent tables. Instead, the bit maps for such a class were previously
1731        created as the appropriate unions of the upper, lower, and digit bitmaps.
1732        Now they are created by subtraction from the [[:word:]] class, which has
1733        its own bitmap.
1735     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1736        It is created by subtracting the vertical space characters (\x09, \x0a,
1737        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1738        subtraction was done in the overall bitmap for a character class, meaning
1739        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1740        be recognized. This bug has been fixed.
1742     7. Patches from the folks at Google:
1744          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1745          real life, but is still worth protecting against".
1747          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1748          regular expressions".
1750          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1751          have it.
1753          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1754          "configure" and the latter not, in order to fix a problem somebody had
1755          with compiling the Arg class on HP-UX.
1757          (e) Improve the error-handling of the C++ wrapper a little bit.
1759          (f) New tests for checking recursion limiting.
1761     8. The pcre_memmove() function, which is used only if the environment does not
1762        have a standard memmove() function (and is therefore rarely compiled),
1763        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1764        returning a result (though PCRE never actually uses the result).
1766     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1767        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1768        returned instead of calling malloc() with an overflowing number that would
1769        most likely cause subsequent chaos.
1771    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1773    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1774        with this option is matched, the nmatch and pmatch options of regexec() are
1775        ignored.
1777    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1778        provided in case anyone wants to the the POSIX interface with UTF-8
1779        strings.
1781    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1782        C++ linking (needed for some HP-UX environments).
1784    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1785        (unused parameter) and in the pcre_printint() function (omitted "default"
1786        switch label when the default is to do nothing).
1788    15. Added some code to make it possible, when PCRE is compiled as a C++
1789        library, to replace subject pointers for pcre_exec() with a smart pointer
1790        class, thus making it possible to process discontinuous strings.
1792    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1793        much the same function. They were added by different people who were trying
1794        to make PCRE easy to compile on non-Unix systems. It has been suggested
1795        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1796        for compiling on Windows systems. I have therefore replaced it with
1797        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1798        defaults to "extern" for C or "extern C" for C++, which works fine on
1799        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1800        SCOPE with something explicit in config.h. In addition:
1802        (a) pcreposix.h still had just "extern" instead of either of these macros;
1803            I have replaced it with PCRE_DATA_SCOPE.
1805        (b) Functions such as _pcre_xclass(), which are internal to the library,
1806            but external in the C sense, all had PCRE_EXPORT in their definitions.
1807            This is apparently wrong for the Windows case, so I have removed it.
1808            (It makes no difference on Unix-like systems.)
1810    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1811        of recursive calls to match(). This is different to MATCH_LIMIT because
1812        that limits the total number of calls to match(), not all of which increase
1813        the depth of recursion. Limiting the recursion depth limits the amount of
1814        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1815        when PCRE is compiled, and changed at run time. A patch from Google adds
1816        this functionality to the C++ interface.
1818    18. Changes to the handling of Unicode character properties:
1820        (a) Updated the table to Unicode 4.1.0.
1822        (b) Recognize characters that are not in the table as "Cn" (undefined).
1824        (c) I revised the way the table is implemented to a much improved format
1825            which includes recognition of ranges. It now supports the ranges that
1826            are defined in UnicodeData.txt, and it also amalgamates other
1827            characters into ranges. This has reduced the number of entries in the
1828            table from around 16,000 to around 3,000, thus reducing its size
1829            considerably. I realized I did not need to use a tree structure after
1830            all - a binary chop search is just as efficient. Having reduced the
1831            number of entries, I extended their size from 6 bytes to 8 bytes to
1832            allow for more data.
1834        (d) Added support for Unicode script names via properties such as \p{Han}.
1836    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1837        matching that character.
1839    20. When matching a repeated Unicode property with a minimum greater than zero,
1840        (for example \pL{2,}), PCRE could look past the end of the subject if it
1841        reached it while seeking the minimum number of characters. This could
1842        happen only if some of the characters were more than one byte long, because
1843        there is a check for at least the minimum number of bytes.
1845    21. Refactored the implementation of \p and \P so as to be more general, to
1846        allow for more different types of property in future. This has changed the
1847        compiled form incompatibly. Anybody with saved compiled patterns that use
1848        \p or \P will have to recompile them.
1850    22. Added "Any" and "L&" to the supported property types.
1852    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1853        but give a compile time error if the value is greater than 0xff.
1855    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1856        accidentally not being installed or uninstalled.
1858    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1859        made were to insert the current release number. This seemed silly, because
1860        it made things harder for people building PCRE on systems that don't run
1861        "configure". I have turned pcre.h into a distributed file, no longer built
1862        by "configure", with the version identification directly included. There is
1863        no longer a pcre.h.in file.
1865        However, this change necessitated a change to the pcre-config script as
1866        well. It is built from pcre-config.in, and one of the substitutions was the
1867        release number. I have updated configure.ac so that ./configure now finds
1868        the release number by grepping pcre.h.
1870    26. Added the ability to run the tests under valgrind.
1873    Version 6.4 05-Sep-05
1874    ---------------------
1876     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1877        "--" to be printed when multiple files were scanned, even when none of the
1878        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1879        consider it to be a bug, and have restored the previous behaviour.
1881     2. A couple of code tidies to get rid of compiler warnings.
1883     3. The pcretest program used to cheat by referring to symbols in the library
1884        whose names begin with _pcre_. These are internal symbols that are not
1885        really supposed to be visible externally, and in some environments it is
1886        possible to suppress them. The cheating is now confined to including
1887        certain files from the library's source, which is a bit cleaner.
1889     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1890        file's purpose clearer.
1892     5. Reorganized pcre_ucp_findchar().
1895    Version 6.3 15-Aug-05
1896    ---------------------
1898     1. The file libpcre.pc.in did not have general read permission in the tarball.
1900     2. There were some problems when building without C++ support:
1902        (a) If C++ support was not built, "make install" and "make test" still
1903            tried to test it.
1905        (b) There were problems when the value of CXX was explicitly set. Some
1906            changes have been made to try to fix these, and ...
1908        (c) --disable-cpp can now be used to explicitly disable C++ support.
1910        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1911            backslash in a target when C++ was disabled. This confuses some
1912            versions of "make", apparently. Using an intermediate variable solves
1913            this. (Same for CPP_LOBJ.)
1915     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1916        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1917        necessary on certain architectures.
1919     4. Added a setting of -export-symbols-regex to the link command to remove
1920        those symbols that are exported in the C sense, but actually are local
1921        within the library, and not documented. Their names all begin with
1922        "_pcre_". This is not a perfect job, because (a) we have to except some
1923        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1924        available (and never for static libraries). I have made a note to try to
1925        find a way round (a) in the future.
1928    Version 6.2 01-Aug-05
1929    ---------------------
1931     1. There was no test for integer overflow of quantifier values. A construction
1932        such as {1111111111111111} would give undefined results. What is worse, if
1933        a minimum quantifier for a parenthesized subpattern overflowed and became
1934        negative, the calculation of the memory size went wrong. This could have
1935        led to memory overwriting.
1937     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1939     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1940        operating environments where this matters.
1942     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1943        PCRE options from within the C++ wrapper.
1945     5. Named capturing subpatterns were not being correctly counted when a pattern
1946        was compiled. This caused two problems: (a) If there were more than 100
1947        such subpatterns, the calculation of the memory needed for the whole
1948        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1949        back references of the form \12, where the number was greater than 9, were
1950        not recognized as back references, even though there were sufficient
1951        previous subpatterns.
1953     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1954        versions of gcc, e.g. 2.95.4.
1957    Version 6.1 21-Jun-05
1958    ---------------------
1960     1. There was one reference to the variable "posix" in pcretest.c that was not
1961        surrounded by "#if !defined NOPOSIX".
1963     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1964        the cross-check on the old pcre_info() function, for the benefit of the
1965        cut-down version of PCRE that is currently imported into Exim.
1967     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1968        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1969        patterns that start (?i) but I don't think that matters. The use of (?i) is
1970        just an example; this all applies to the other options as well.
1972     4. Since libtool seems to echo the compile commands it is issuing, the output
1973        from "make" can be reduced a bit by putting "@" in front of each libtool
1974        compile command.
1976     5. Patch from the folks at Google for configure.in to be a bit more thorough
1977        in checking for a suitable C++ installation before trying to compile the
1978        C++ stuff. This should fix a reported problem when a compiler was present,
1979        but no suitable headers.
1981     6. The man pages all had just "PCRE" as their title. I have changed them to
1982        be the relevant file name. I have also arranged that these names are
1983        retained in the file doc/pcre.txt, which is a concatenation in text format
1984        of all the man pages except the little individual ones for each function.
1986     7. The NON-UNIX-USE file had not been updated for the different set of source
1987        files that come with release 6. I also added a few comments about the C++
1988        wrapper.
1991    Version 6.0 07-Jun-05
1992    ---------------------
1994     1. Some minor internal re-organization to help with my DFA experiments.
1996     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1997        didn't matter for the library itself when fully configured, but did matter
1998        when compiling without UCP support, or within Exim, where the ucp files are
1999        not imported.
2001     3. Refactoring of the library code to split up the various functions into
2002        different source modules. The addition of the new DFA matching code (see
2003        below) to a single monolithic source would have made it really too
2004        unwieldy, quite apart from causing all the code to be include in a
2005        statically linked application, when only some functions are used. This is
2006        relevant even without the DFA addition now that patterns can be compiled in
2007        one application and matched in another.
2009        The downside of splitting up is that there have to be some external
2010        functions and data tables that are used internally in different modules of
2011        the library but which are not part of the API. These have all had their
2012        names changed to start with "_pcre_" so that they are unlikely to clash
2013        with other external names.
2015     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2016        a different (DFA) algorithm. Although it is slower than the original
2017        function, it does have some advantages for certain types of matching
2018        problem.
2020     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2021        including restarting after a partial match.
2023     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2024        defined when compiling for Windows was sent to me. I have put it into the
2025        code, though I have no means of testing or verifying it.
2027     7. Added the pcre_refcount() auxiliary function.
2029     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2030        match before or at the first newline in the subject string. In pcretest,
2031        the /f option on a pattern can be used to set this.
2033     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2034        would behave wrongly. This has been present in PCRE since release 4.0.
2036    10. A number of changes to the pcregrep command:
2038        (a) Refactored how -x works; insert ^(...)$ instead of setting
2039            PCRE_ANCHORED and checking the length, in preparation for adding
2040            something similar for -w.
2042        (b) Added the -w (match as a word) option.
2044        (c) Refactored the way lines are read and buffered so as to have more
2045            than one at a time available.
2047        (d) Implemented a pcregrep test script.
2049        (e) Added the -M (multiline match) option. This allows patterns to match
2050            over several lines of the subject. The buffering ensures that at least
2051            8K, or the rest of the document (whichever is the shorter) is available
2052            for matching (and similarly the previous 8K for lookbehind assertions).
2054        (f) Changed the --help output so that it now says
2056              -w, --word-regex(p)
2058            instead of two lines, one with "regex" and the other with "regexp"
2059            because that confused at least one person since the short forms are the
2060            same. (This required a bit of code, as the output is generated
2061            automatically from a table. It wasn't just a text change.)
2063        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2064            option but starts with a hyphen. Could be a pattern or a path name
2065            starting with a hyphen, for instance.
2067        (h) "-" can be given as a file name to represent stdin.
2069        (i) When file names are being printed, "(standard input)" is used for
2070            the standard input, for compatibility with GNU grep. Previously
2071            "<stdin>" was used.
2073        (j) The option --label=xxx can be used to supply a name to be used for
2074            stdin when file names are being printed. There is no short form.
2076        (k) Re-factored the options decoding logic because we are going to add
2077            two more options that take data. Such options can now be given in four
2078            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2080        (l) Added the -A, -B, and -C options for requesting that lines of context
2081            around matches be printed.
2083        (m) Added the -L option to print the names of files that do not contain
2084            any matching lines, that is, the complement of -l.
2086        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2087            continue to scan other files.
2089        (o) The -s option was incorrectly implemented. For compatibility with other
2090            greps, it now suppresses the error message for a non-existent or non-
2091            accessible file (but not the return code). There is a new option called
2092            -q that suppresses the output of matching lines, which was what -s was
2093            previously doing.
2095        (p) Added --include and --exclude options to specify files for inclusion
2096            and exclusion when recursing.
2098    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2099        Hopefully, it now does.
2101    12. Missing cast in pcre_study().
2103    13. Added an "uninstall" target to the makefile.
2105    14. Replaced "extern" in the function prototypes in Makefile.in with
2106        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2107        world, but is set differently for Windows.
2109    15. Added a second compiling function called pcre_compile2(). The only
2110        difference is that it has an extra argument, which is a pointer to an
2111        integer error code. When there is a compile-time failure, this is set
2112        non-zero, in addition to the error test pointer being set to point to an
2113        error message. The new argument may be NULL if no error number is required
2114        (but then you may as well call pcre_compile(), which is now just a
2115        wrapper). This facility is provided because some applications need a
2116        numeric error indication, but it has also enabled me to tidy up the way
2117        compile-time errors are handled in the POSIX wrapper.
2119    16. Added VPATH=.libs to the makefile; this should help when building with one
2120        prefix path and installing with another. (Or so I'm told by someone who
2121        knows more about this stuff than I do.)
2123    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2124        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2125        match everything, including newlines. This is not POSIX-compatible, but
2126        somebody wanted the feature. From pcretest it can be activated by using
2127        both the P and the s flags.
2129    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2131    19. libpcre.pc was being incorrectly installed as executable.
2133    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2134        it now also looks for '\r' so that it will work unmodified on Windows.
2136    21. Added Google's contributed C++ wrapper to the distribution.
2138    22. Added some untidy missing memory free() calls in pcretest, to keep
2139        Electric Fence happy when testing.
2143    Version 5.0 13-Sep-04
2144    ---------------------
2146     1. Internal change: literal characters are no longer packed up into items
2147        containing multiple characters in a single byte-string. Each character
2148        is now matched using a separate opcode. However, there may be more than one
2149        byte in the character in UTF-8 mode.
2151     2. The pcre_callout_block structure has two new fields: pattern_position and
2152        next_item_length. These contain the offset in the pattern to the next match
2153        item, and its length, respectively.
2155     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2156        insertion of callouts before each pattern item. Added the /C option to
2157        pcretest to make use of this.
2159     4. On the advice of a Windows user, the lines
2161          #if defined(_WIN32) || defined(WIN32)
2162          _setmode( _fileno( stdout ), 0x8000 );
2163          #endif  /* defined(_WIN32) || defined(WIN32) */
2165        have been added to the source of pcretest. This apparently does useful
2166        magic in relation to line terminators.
2168     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2169        for the benefit of those environments where the "b" makes a difference.
2171     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2172        to know about it. I have put a hack into configure.in that adds in code
2173        to set GCC=yes if CC=icc. This seems to end up at a point in the
2174        generated configure script that is early enough to affect the setting of
2175        compiler options, which is what is needed, but I have no means of testing
2176        whether it really works. (The user who reported this had patched the
2177        generated configure script, which of course I cannot do.)
2179        LATER: After change 22 below (new libtool files), the configure script
2180        seems to know about icc (and also ecc). Therefore, I have commented out
2181        this hack in configure.in.
2183     7. Added support for pkg-config (2 patches were sent in).
2185     8. Negated POSIX character classes that used a combination of internal tables
2186        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2187        [[:^ascii]]. Typically, they would match almost any characters. The other
2188        POSIX classes were not broken in this way.
2190     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2191        to find the match, as PCRE was deluded into thinking that the match had to
2192        start at the start point or following a newline. The same bug applied to
2193        patterns with negative forward assertions or any backward assertions
2194        preceding ".*" at the start, unless the pattern required a fixed first
2195        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2197    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2198        starting at the last subject character, bytes beyond the end of the subject
2199        string were read.
2201    11. Renamed the variable "class" as "classbits" to make life easier for C++
2202        users. (Previously there was a macro definition, but it apparently wasn't
2203        enough.)
2205    12. Added the new field "tables" to the extra data so that tables can be passed
2206        in at exec time, or the internal tables can be re-selected. This allows
2207        a compiled regex to be saved and re-used at a later time by a different
2208        program that might have everything at different addresses.
2210    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2211        -R library as well as a -L library.
2213    14. The debugging options of pcretest (-d on the command line or D on a
2214        pattern) showed incorrect output for anything following an extended class
2215        that contained multibyte characters and which was followed by a quantifier.
2217    15. Added optional support for general category Unicode character properties
2218        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2219        support. It adds about 90K to the size of the library. The meanings of the
2220        inbuilt class escapes such as \d and \s have NOT been changed.
2222    16. Updated pcredemo.c to include calls to free() to release the memory for the
2223        compiled pattern.
2225    17. The generated file chartables.c was being created in the source directory
2226        instead of in the building directory. This caused the build to fail if the
2227        source directory was different from the building directory, and was
2228        read-only.
2230    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2231        file. No doubt somebody will tell me if they don't make sense... Also added
2232        Dan Mooney's comments about building on OpenVMS.
2234    19. Added support for partial matching via the PCRE_PARTIAL option for
2235        pcre_exec() and the \P data escape in pcretest.
2237    20. Extended pcretest with 3 new pattern features:
2239        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2240              write the compiled pattern to the file whose name is "rest-of-line".
2241              This is a straight binary dump of the data, with the saved pointer to
2242              the character tables forced to be NULL. The study data, if any, is
2243              written too. After writing, pcretest reads a new pattern.
2245        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2246              compiled pattern from the given file. There must not be any
2247              occurrences of "<" in the file name (pretty unlikely); if there are,
2248              pcretest will instead treat the initial "<" as a pattern delimiter.
2249              After reading in the pattern, pcretest goes on to read data lines as
2250              usual.
2252        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2253              and 16-bit fields in a compiled pattern, to simulate a pattern that
2254              was compiled on a host of opposite endianness.
2256    21. The pcre-exec() function can now cope with patterns that were compiled on
2257        hosts of opposite endianness, with this restriction:
2259          As for any compiled expression that is saved and used later, the tables
2260          pointer field cannot be preserved; the extra_data field in the arguments
2261          to pcre_exec() should be used to pass in a tables address if a value
2262          other than the default internal tables were used at compile time.
2264    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2265        now diagnosed as an error. Previously, most of the time, a negative number
2266        would have been treated as zero, but if in addition "ovector" was passed as
2267        NULL, a crash could occur.
2269    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2270        new versions from the libtool 1.5 distribution (the last one is a copy of
2271        a file called libtool.m4). This seems to have fixed the need to patch
2272        "configure" to support Darwin 1.3 (which I used to do). However, I still
2273        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2274        workstation).
2276    24. Changed the PCRE licence to be the more standard "BSD" licence.
2279    Version 4.5 01-Dec-03
2280    ---------------------
2282     1. There has been some re-arrangement of the code for the match() function so
2283        that it can be compiled in a version that does not call itself recursively.
2284        Instead, it keeps those local variables that need separate instances for
2285        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2286        needs to "recurse". Keeping track of where control must go is done by means
2287        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2288        hide most of the details from the main code, and operates only if
2289        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2290        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2291        operating.
2293        To make it easier for callers to provide specially tailored get/free
2294        functions for this usage, two new functions, pcre_stack_malloc, and
2295        pcre_stack_free, are used. They are always called in strict stacking order,
2296        and the size of block requested is always the same.
2298        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2299        PCRE has been compiled to use the stack or the heap for recursion. The
2300        -C option of pcretest uses this to show which version is compiled.
2302        A new data escape \S, is added to pcretest; it causes the amounts of store
2303        obtained and freed by both kinds of malloc/free at match time to be added
2304        to the output.
2306     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2307        what's available on my current Linux desktop machine.
2309     3. When matching a UTF-8 string, the test for a valid string at the start has
2310        been extended. If start_offset is not zero, PCRE now checks that it points
2311        to a byte that is the start of a UTF-8 character. If not, it returns
2312        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2313        this is necessary because there may be backward assertions in the pattern.
2314        When matching the same subject several times, it may save resources to use
2315        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2317     4. The code for checking the validity of UTF-8 strings has been tightened so
2318        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2319        containing "overlong sequences".
2321     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2322        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2323        should have been "&", but it just so happened that all the cases this let
2324        through by mistake were picked up later in the function.
2326     6. I had used a variable called "isblank" - this is a C99 function, causing
2327        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2329     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2330        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2331        so the version is shown; (c) stop "make test" echoing "./RunTest".
2333     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2335     9. The prototype for memmove() for systems that don't have it was using
2336        size_t, but the inclusion of the header that defines size_t was later. I've
2337        moved the #includes for the C headers earlier to avoid this.
2339    10. Added some adjustments to the code to make it easier to compiler on certain
2340        special systems:
2342          (a) Some "const" qualifiers were missing.
2343          (b) Added the macro EXPORT before all exported functions; by default this
2344              is defined to be empty.
2345          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2346              that it reads its output file name as an argument instead of writing
2347              to the standard output and assuming this can be redirected.
2349    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2350        class containing characters with values greater than 255, PCRE compilation
2351        went into a loop.
2353    12. A recursive reference to a subpattern that was within another subpattern
2354        that had a minimum quantifier of zero caused PCRE to crash. For example,
2355        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2356        recursion. If the recursively-called subpattern itself had a zero repeat,
2357        that was OK.
2359    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2360        buffer into which it was copied (for escape processing) was still set at
2361        1024, so long lines caused crashes.
2363    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2364        "internal error: code overflow...". This applied to any character class
2365        that was followed by a possessive quantifier.
2367    15. Modified the Makefile to add libpcre.la as a prerequisite for
2368        libpcreposix.la because I was told this is needed for a parallel build to
2369        work.
2371    16. If a pattern that contained .* following optional items at the start was
2372        studied, the wrong optimizing data was generated, leading to matching
2373        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2374        matching string must start with a or b or c. The correct conclusion for
2375        this pattern is that a match can start with any character.
2378    Version 4.4 13-Aug-03
2379    ---------------------
2381     1. In UTF-8 mode, a character class containing characters with values between
2382        127 and 255 was not handled correctly if the compiled pattern was studied.
2383        In fixing this, I have also improved the studying algorithm for such
2384        classes (slightly).
2386     2. Three internal functions had redundant arguments passed to them. Removal
2387        might give a very teeny performance improvement.
2389     3. Documentation bug: the value of the capture_top field in a callout is *one
2390        more than* the number of the hightest numbered captured substring.
2392     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2393        in incorrectly linking with a previously installed version. They now link
2394        explicitly with libpcre.la.
2396     5. configure.in no longer needs to recognize Cygwin specially.
2398     6. A problem in pcre.in for Windows platforms is fixed.
2400     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2401        pcretest, it used to include the size of the study block as part of its
2402        output. Unfortunately, the structure contains a field that has a different
2403        size on different hardware architectures. This meant that the tests that
2404        showed this size failed. As the block is currently always of a fixed size,
2405        this information isn't actually particularly useful in pcretest output, so
2406        I have just removed it.
2408     8. Three pre-processor statements accidentally did not start in column 1.
2409        Sadly, there are *still* compilers around that complain, even though
2410        standard C has not required this for well over a decade. Sigh.
2412     9. In pcretest, the code for checking callouts passed small integers in the
2413        callout_data field, which is a void * field. However, some picky compilers
2414        complained about the casts involved for this on 64-bit systems. Now
2415        pcretest passes the address of the small integer instead, which should get
2416        rid of the warnings.
2418    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2419        both compile and run time, and gives an error if an invalid UTF-8 sequence
2420        is found. There is a option for disabling this check in cases where the
2421        string is known to be correct and/or the maximum performance is wanted.
2423    11. In response to a bug report, I changed one line in Makefile.in from
2425            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2426        to
2427            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2429        to look similar to other lines, but I have no way of telling whether this
2430        is the right thing to do, as I do not use Windows. No doubt I'll get told
2431        if it's wrong...
2434    Version 4.3 21-May-03
2435    ---------------------
2437    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2438       Makefile.
2440    2. Some refactoring to improve the quality of the code:
2442       (i)   The utf8_table... variables are now declared "const".
2444       (ii)  The code for \cx, which used the "case flipping" table to upper case
2445             lower case letters, now just substracts 32. This is ASCII-specific,
2446             but the whole concept of \cx is ASCII-specific, so it seems
2447             reasonable.
2449       (iii) PCRE was using its character types table to recognize decimal and
2450             hexadecimal digits in the pattern. This is silly, because it handles
2451             only 0-9, a-f, and A-F, but the character types table is locale-
2452             specific, which means strange things might happen. A private
2453             table is now used for this - though it costs 256 bytes, a table is
2454             much faster than multiple explicit tests. Of course, the standard
2455             character types table is still used for matching digits in subject
2456             strings against \d.
2458       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2459             ending in _t are). So I've renamed it as ESC_tee.
2461    3. The first argument for regexec() in the POSIX wrapper should have been
2462       defined as "const".
2464    4. Changed pcretest to use malloc() for its buffers so that they can be
2465       Electric Fenced for debugging.
2467    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2468       to read one or more bytes before the start of the subject string. Often this
2469       had no effect on PCRE's behaviour, but in some circumstances it could
2470       provoke a segmentation fault.
2472    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2473       to try to read one or more bytes before the start of the subject string.
2475    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2476       UTF-8 support could misbehave in various ways if the subject string
2477       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2478       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2479       back over UTF-8 characters.)
2482    Version 4.2 14-Apr-03
2483    ---------------------
2485    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2487    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2488         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2489         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2490         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2491         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2492           and BUILD_EXEEXT
2493         Note: automatic setting of the BUILD variables is not yet working
2494         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2495           compile-time but not at link-time
2496         [LINK]: use for linking executables only
2497         make different versions for Windows and non-Windows
2498         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2499           libraries
2500         [LINK_FOR_BUILD]: new variable
2501         [OBJEXT]: use throughout
2502         [EXEEXT]: use throughout
2503         <winshared>: new target
2504         <wininstall>: new target
2505         <dftables.o>: use native compiler
2506         <dftables>: use native linker
2507         <install>: handle Windows platform correctly
2508         <clean>: ditto
2509         <check>: ditto
2510         copy DLL to top builddir before testing
2512       As part of these changes, -no-undefined was removed again. This was reported
2513       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2514       in any case.
2516    3. Some tidies to get rid of compiler warnings:
2518       . In the match_data structure, match_limit was an unsigned long int, whereas
2519         match_call_count was an int. I've made them both unsigned long ints.
2521       . In pcretest the fact that a const uschar * doesn't automatically cast to
2522         a void * provoked a warning.
2524       . Turning on some more compiler warnings threw up some "shadow" variables
2525         and a few more missing casts.
2527    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2528       option, a class that contained a single character with a value between 128
2529       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2531    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2532       option, a class that contained several characters, but with at least one
2533       whose value was between 128 and 255 caused PCRE to crash.
2536    Version 4.1 12-Mar-03
2537    ---------------------
2539    1. Compiling with gcc -pedantic found a couple of places where casts were
2540    needed, and a string in dftables.c that was longer than standard compilers are
2541    required to support.
2543    2. Compiling with Sun's compiler found a few more places where the code could
2544    be tidied up in order to avoid warnings.
2546    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2547    first of these names is deprecated in the latest Autoconf in favour of the name
2548    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2549    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2550    analogy I have changed it to CFLAGS_FOR_BUILD.
2552    4. Added -no-undefined to the linking command in the Makefile, because this is
2553    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2554    linking step for the pcreposix library.
2556    5. PCRE was failing to diagnose the case of two named groups with the same
2557    name.
2559    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2560    literal character that is needed in the subject for a match, and scans along to
2561    ensure that it is present before embarking on the full matching process. This
2562    saves time in cases of nested unlimited repeats that are never going to match.
2563    Problem: the scan can take a lot of time if the subject is very long (e.g.
2564    megabytes), thus penalizing straightforward matches. It is now done only if the
2565    amount of subject to be scanned is less than 1000 bytes.
2567    7. A lesser problem with the same optimization is that it was recording the
2568    first character of an anchored pattern as "needed", thus provoking a search
2569    right along the subject, even when the first match of the pattern was going to
2570    fail. The "needed" character is now not set for anchored patterns, unless it
2571    follows something in the pattern that is of non-fixed length. Thus, it still
2572    fulfils its original purpose of finding quick non-matches in cases of nested
2573    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2576    Version 4.0 17-Feb-03
2577    ---------------------
2579    1. If a comment in an extended regex that started immediately after a meta-item
2580    extended to the end of string, PCRE compiled incorrect data. This could lead to
2581    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2583    2. Moved to autoconf 2.53 and libtool 1.4.2.
2585    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2586    the special perltest8 script is no longer needed - all the tests can be run
2587    from a single perltest script.
2589    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2590    by \s. It has now been removed in PCRE. This means it isn't recognized as
2591    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2592    class [:space:] *does* include VT, thereby creating a mess.
2594    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2595    space and tab.
2597    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2598    its new features into the main test script, reducing the number of scripts.
2600    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2601    were backward compatible, and made the (?i) apply to the whole pattern, as if
2602    /i were given. Now it behaves more logically, and applies the option setting
2603    only to what follows. PCRE has been changed to follow suit. However, if it
2604    finds options settings right at the start of the pattern, it extracts them into
2605    the global options, as before. Thus, they show up in the info data.
2607    8. Added support for the \Q...\E escape sequence. Characters in between are
2608    treated as literals. This is slightly different from Perl in that $ and @ are
2609    also handled as literals inside the quotes. In Perl, they will cause variable
2610    interpolation. Note the following examples:
2612        Pattern            PCRE matches      Perl matches
2614        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2615        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2616        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2618    For compatibility with Perl, \Q...\E sequences are recognized inside character
2619    classes as well as outside them.
2621    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2622    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2623    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2624    signed/unsigned warnings.
2626    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2627    option for pcretest, so I've replaced it by a simple function that does just
2628    that job.
2630    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2631    "pcregrep -".
2633    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2634    Java package. This provides some syntactic sugar for simple cases of what my
2635    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2636    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2637    item, you can use this simplified notation. Note that only makes sense with
2638    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2639    greediness, whatever the setting of the PCRE_UNGREEDY option.
2641    13. A change of greediness default within a pattern was not taking effect at
2642    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2643    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2644    was abstracted outside.
2646    14. PCRE now supports the \G assertion. It is true when the current matching
2647    position is at the start point of the match. This differs from \A when the
2648    starting offset is non-zero. Used with the /g option of pcretest (or similar
2649    code), it works in the same way as it does for Perl's /g option. If all
2650    alternatives of a regex begin with \G, the expression is anchored to the start
2651    match position, and the "anchored" flag is set in the compiled expression.
2653    15. Some bugs concerning the handling of certain option changes within patterns
2654    have been fixed. These applied to options other than (?ims). For example,
2655    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2656    been the other way round. Some of this was related to change 7 above.
2658    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2659    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2660    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2661    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2663    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2664    mode. Unlike ".", it always matches newline, whatever the setting of
2665    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2666    assertions. Perl allows it, but it doesn't (in general) work because it can't
2667    calculate the length of the lookbehind. At least, that's the case for Perl
2668    5.8.0 - I've been told they are going to document that it doesn't work in
2669    future.
2671    18. Added an error diagnosis for escapes that PCRE does not support: these are
2672    \L, \l, \N, \P, \p, \U, \u, and \X.
2674    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2675    reading past the end of the pattern in cases such as /[abcd/.
2677    20. PCRE was getting more memory than necessary for patterns with classes that
2678    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2680    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2681    compiling PCRE for use with Virtual Pascal.
2683    22. Small fix to the Makefile to make it work properly if the build is done
2684    outside the source tree.
2686    23. Added a new extension: a condition to go with recursion. If a conditional
2687    subpattern starts with (?(R) the "true" branch is used if recursion has
2688    happened, whereas the "false" branch is used only at the top level.
2690    24. When there was a very long string of literal characters (over 255 bytes
2691    without UTF support, over 250 bytes with UTF support), the computation of how
2692    much memory was required could be incorrect, leading to segfaults or other
2693    strange effects.
2695    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2696    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2697    there was a subsequent back reference to those brackets. This meant that, for
2698    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2699    possible to check for precisely this case. All we can do is abandon the
2700    optimization if .* occurs inside capturing brackets when there are any back
2701    references whatsoever. (See below for a better fix that came later.)
2703    26. The handling of the optimization for finding the first character of a
2704    non-anchored pattern, and for finding a character that is required later in the
2705    match were failing in some cases. This didn't break the matching; it just
2706    failed to optimize when it could. The way this is done has been re-implemented.
2708    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2710    28. Added a new feature that provides some of the functionality that Perl
2711    provides with (?{...}). The facility is termed a "callout". The way it is done
2712    in PCRE is for the caller to provide an optional function, by setting
2713    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2714    global variable. By default it is unset, which disables all calling out. To get
2715    the function called, the regex must include (?C) at appropriate points. This
2716    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2717    This provides a means of identifying different callout points. When PCRE
2718    reaches such a point in the regex, if pcre_callout has been set, the external
2719    function is called. It is provided with data in a structure called
2720    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2721    matching continues; if it returns a non-zero value, the match at the current
2722    point fails. However, backtracking will occur if possible. [This was changed
2723    later and other features added - see item 49 below.]
2725    29. pcretest is upgraded to test the callout functionality. It provides a
2726    callout function that displays information. By default, it shows the start of
2727    the match and the current position in the text. There are some new data escapes
2728    to vary what happens:
2730        \C+         in addition, show current contents of captured substrings
2731        \C-         do not supply a callout function
2732        \C!n        return 1 when callout number n is reached
2733        \C!n!m      return 1 when callout number n is reached for the mth time
2735    30. If pcregrep was called with the -l option and just a single file name, it
2736    output "<stdin>" if a match was found, instead of the file name.
2738    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2739    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2740    pcre_exec(). This saves a malloc/free per call. The default value of
2741    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2742    when configuring.
2744    32. The default maximum size of a compiled pattern is 64K. There have been a
2745    few cases of people hitting this limit. The code now uses macros to handle the
2746    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2747    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2748    configuring. Tests 2 and 5 work only with 2-byte links because they output
2749    debugging information about compiled patterns.
2751    33. Internal code re-arrangements:
2753    (a) Moved the debugging function for printing out a compiled regex into
2754        its own source file (printint.c) and used #include to pull it into
2755        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2756        separate copies.
2758    (b) Defined the list of op-code names for debugging as a macro in
2759        internal.h so that it is next to the definition of the opcodes.
2761    (c) Defined a table of op-code lengths for simpler skipping along compiled
2762        code. This is again a macro in internal.h so that it is next to the
2763        definition of the opcodes.
2765    34. Added support for recursive calls to individual subpatterns, along the
2766    lines of Robin Houston's patch (but implemented somewhat differently).
2768    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2769    allow it to read and process whole directories in Win32. This code was
2770    contributed by Lionel Fourquaux; it has not been tested by me.
2772    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2773    used to name a group. Names consist of alphanumerics and underscores, and must
2774    be unique. Back references use the syntax (?P=name) and recursive calls use
2775    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2776    numbers. The function pcre_fullinfo() can be used after compilation to extract
2777    a name/number map. There are three relevant calls:
2779      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2780      PCRE_INFO_NAMECOUNT            yields the number of entries
2781      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2783    The map is a vector of fixed-size entries. The size of each entry depends on
2784    the length of the longest name used. The first two bytes of each entry are the
2785    group number, most significant byte first. There follows the corresponding
2786    name, zero terminated. The names are in alphabetical order.
2788    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2789    case instead of 255. Making it the same both with and without UTF-8 support
2790    means that the same test output works with both.
2792    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2793    calling malloc() with a zero argument.
2795    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2796    optimization. I've improved things by keeping a bitmap of backreferences with
2797    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2798    fact referenced, the optimization can be applied. It is unlikely that a
2799    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2800    the match to follow \n) will appear inside brackets with a number greater than
2801    31, but if it does, any back reference > 31 suppresses the optimization.
2803    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2804    of disabling numbered capturing parentheses. Any opening parenthesis that is
2805    not followed by ? behaves as if it were followed by ?: but named parentheses
2806    can still be used for capturing (and they will acquire numbers in the usual
2807    way).
2809    41. Redesigned the return codes from the match() function into yes/no/error so
2810    that errors can be passed back from deep inside the nested calls. A malloc
2811    failure while inside a recursive subpattern call now causes the
2812    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2814    42. It is now possible to set a limit on the number of times the match()
2815    function is called in a call to pcre_exec(). This facility makes it possible to
2816    limit the amount of recursion and backtracking, though not in a directly
2817    obvious way, because the match() function is used in a number of different
2818    circumstances. The count starts from zero for each position in the subject
2819    string (for non-anchored patterns). The default limit is, for compatibility, a
2820    large number, namely 10 000 000. You can change this in two ways:
2822    (a) When configuring PCRE before making, you can use --with-match-limit=n
2823        to set a default value for the compiled library.
2825    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2826        a different value is set. See 45 below.
2828    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2830    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2831    of things that can be changed at compile time. The first argument specifies
2832    what is wanted and the second points to where the information is to be placed.
2833    The current list of available information is:
2835      PCRE_CONFIG_UTF8
2837    The output is an integer that is set to one if UTF-8 support is available;
2838    otherwise it is set to zero.
2842    The output is an integer that it set to the value of the code that is used for
2843    newline. It is either LF (10) or CR (13).
2847    The output is an integer that contains the number of bytes used for internal
2848    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2852    The output is an integer that contains the threshold above which the POSIX
2853    interface uses malloc() for output vectors. See item 31 above.
2857    The output is an unsigned integer that contains the default limit of the number
2858    of match() calls in a pcre_exec() execution. See 42 above.
2860    44. pcretest has been upgraded by the addition of the -C option. This causes it
2861    to extract all the available output from the new pcre_config() function, and to
2862    output it. The program then exits immediately.
2864    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2865    order to support additional features. One way would have been to define
2866    pcre_exec2() (for example) with extra arguments, but this would not have been
2867    extensible, and would also have required all calls to the original function to
2868    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2869    is used for passing in "extra" data from pcre_study().
2871    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2872    contains the following fields:
2874      flags         a bitmap indicating which of the following fields are set
2875      study_data    opaque data from pcre_study()
2876      match_limit   a way of specifying a limit on match() calls for a specific
2877                      call to pcre_exec()
2878      callout_data  data for callouts (see 49 below)
2880    The flag bits are also defined in pcre.h, and are
2886    The pcre_study() function now returns one of these new pcre_extra blocks, with
2887    the actual study data pointed to by the study_data field, and the
2888    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2889    before. That is, this change is entirely upwards-compatible and requires no
2890    change to existing code.
2892    If you want to pass in additional data to pcre_exec(), you can either place it
2893    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2894    block.
2896    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2897    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2898    times with different match limits, until it finds the minimum value needed for
2899    pcre_exec() to complete. The value is then output. This can be instructive; for
2900    most simple matches the number is quite small, but for pathological cases it
2901    gets very large very quickly.
2903    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2904    returns the size of the data block pointed to by the study_data field in a
2905    pcre_extra block, that is, the value that was passed as the argument to
2906    pcre_malloc() when PCRE was getting memory in which to place the information
2907    created by pcre_study(). The fourth argument should point to a size_t variable.
2908    pcretest has been extended so that this information is shown after a successful
2909    pcre_study() call when information about the compiled regex is being displayed.
2911    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2912    because what follows is always an absolute path. (Later: it turns out that this
2913    is more than cosmetic for MinGW, because it doesn't like empty path
2914    components.)
2916    49. Some changes have been made to the callout feature (see 28 above):
2918    (i)  A callout function now has three choices for what it returns:
2920           0  =>  success, carry on matching
2921         > 0  =>  failure at this point, but backtrack if possible
2922         < 0  =>  serious error, return this value from pcre_exec()
2924         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2925         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2926         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2927         use by callout functions. It will never be used by PCRE itself.
2929    (ii) The pcre_extra structure (see 45 above) has a void * field called
2930         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2931         pcre_callout_block structure has a field of the same name. The contents of
2932         the field passed in the pcre_extra structure are passed to the callout
2933         function in the corresponding field in the callout block. This makes it
2934         easier to use the same callout-containing regex from multiple threads. For
2935         testing, the pcretest program has a new data escape
2937           \C*n        pass the number n (may be negative) as callout_data
2939         If the callout function in pcretest receives a non-zero value as
2940         callout_data, it returns that value.
2942    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2943    there were some redundant $(CFLAGS) in commands that are now specified as
2944    $(LINK), which already includes $(CFLAGS).
2946    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2947    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2948    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2949    one-byte characters throughout. Note that case-insensitive matching applies
2950    only to characters whose values are less than 256. PCRE doesn't support the
2951    notion of cases for higher-valued characters.
2953    (i)   A character class whose characters are all within 0-255 is handled as
2954          a bit map, and the map is inverted for negative classes. Previously, a
2955          character > 255 always failed to match such a class; however it should
2956          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2958    (ii)  A negated character class with a single character < 255 is coded as
2959          "not this character" (OP_NOT). This wasn't working properly when the test
2960          character was multibyte, either singly or repeated.
2962    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2963          mode, for example: \x{100}{2,3}.
2965    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2966          singly or repeated) now correctly test multibyte characters. However,
2967          PCRE doesn't recognize any characters with values greater than 255 as
2968          digits, spaces, or word characters. Such characters always match \D, \S,
2969          and \W, and never match \d, \s, or \w.
2971    (v)   Classes may now contain characters and character ranges with values
2972          greater than 255. For example: [ab\x{100}-\x{400}].
2974    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2975          PCRE in UTF-8 mode.
2977    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2978    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2979    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2980    value.)
2982    53. The single man page has become too large. I have therefore split it up into
2983    a number of separate man pages. These also give rise to individual HTML pages;
2984    these are now put in a separate directory, and there is an index.html page that
2985    lists them all. Some hyperlinking between the pages has been installed.
2987    54. Added convenience functions for handling named capturing parentheses.
2989    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2990    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2991    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2992    are faulted.
2994    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2995    calling configure. These values are used when compiling the dftables.c program
2996    which is run to generate the source of the default character tables. They
2997    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2998    you will need to set these values.
3000    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3003    Version 3.9 02-Jan-02
3004  ---------------------  ---------------------
3006  1. A bit of extraneous text had somehow crept into the pcregrep documentation.  1. A bit of extraneous text had somehow crept into the pcregrep documentation.

Removed from v.61  
changed lines
  Added in v.479

  ViewVC Help
Powered by ViewVC 1.1.5