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revision 41 by nigel, Sat Feb 24 21:39:17 2007 UTC revision 432 by ph10, Wed Sep 2 16:02:56 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.00 ??-???-??
5    ----------------------
7    1.  The table for translating pcre_compile() error codes into POSIX error codes
8        was out-of-date, and there was no check on the pcre_compile() error code
9        being within the table. This could lead to an OK return being given in
10        error.
12    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
13        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14        in a Windows environment.
16    3.  The pcregrep --count option prints the count for each file even when it is
17        zero, as does GNU grep. However, pcregrep was also printing all files when
18        --files-with-matches was added. Now, when both options are given, it prints
19        counts only for those files that have at least one match. (GNU grep just
20        prints the file name in this circumstance, but including the count seems
21        more useful - otherwise, why use --count?) Also ensured that the
22        combination -clh just lists non-zero counts, with no names.
24    4.  The long form of the pcregrep -F option was incorrectly implemented as
25        --fixed_strings instead of --fixed-strings. This is an incompatible change,
26        but it seems right to fix it, and I didn't think it was worth preserving
27        the old behaviour.
29    5.  The command line items --regex=pattern and --regexp=pattern were not
30        recognized by pcregrep, which required --regex pattern or --regexp pattern
31        (with a space rather than an '='). The man page documented the '=' forms,
32        which are compatible with GNU grep; these now work.
34    6.  No libpcreposix.pc file was created for pkg-config; there was just
35        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
37    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
38        when UCP support is not needed, by modifying the Python script that
39        generates it from Unicode data files. This should not matter if the module
40        is correctly used as a library, but I received one complaint about 50K of
41        unwanted data. My guess is that the person linked everything into his
42        program rather than using a library. Anyway, it does no harm.
44    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
45        was a minimum greater than 1 for a wide character in a possessive
46        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
47        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
48        character. Chaos in the form of incorrect output or a compiling loop could
49        result.
51    9.  The restrictions on what a pattern can contain when partial matching is
52        requested for pcre_exec() have been removed. All patterns can now be
53        partially matched by this function. In addition, if there are at least two
54        slots in the offset vector, the offsets of the first-encountered partial
55        match are set in them when PCRE_ERROR_PARTIAL is returned.
57    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
58        synonymous with PCRE_PARTIAL, for backwards compatibility, and
59        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
60        and may be more useful for multi-segment matching, especially with
61        pcre_exec().
63    11. Partial matching with pcre_exec() is now more intuitive. A partial match
64        used to be given if ever the end of the subject was reached; now it is
65        given only if matching could not proceed because another character was
66        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
67        string "Z", which now yields "no match" instead of "partial match". In the
68        case of pcre_dfa_exec(), "no match" is given if every matching path for the
69        final character ended with (*FAIL).
71    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
72        if the pattern had a "must contain" character that was already found in the
73        earlier partial match, unless partial matching was again requested. For
74        example, with the pattern /dog.(body)?/, the "must contain" character is
75        "g". If the first part-match was for the string "dog", restarting with
76        "sbody" failed.
78    13. Added a pcredemo man page, created automatically from the pcredemo.c file,
79        so that the demonstration program is easily available in environments where
80        PCRE has not been installed from source.
82    14. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
83        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
84        library.
86    15. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
87        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
88        is not the first non-POSIX option to be added. Clearly some people find
89        these options useful.
92    Version 7.9 11-Apr-09
93    ---------------------
95    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
96        (pcretest), all targets were linked against these libraries. This included
97        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
98        libraries. This caused unwanted dependencies to be created. This problem
99        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
100        pcretest is linked with readline.
102    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
103        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
104        moved outside it again, because FALSE and TRUE are already defined in AIX,
105        but BOOL is not.
107    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
108        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
110    4.  The pcregrep documentation said spaces were inserted as well as colons (or
111        hyphens) following file names and line numbers when outputting matching
112        lines. This is not true; no spaces are inserted. I have also clarified the
113        wording for the --colour (or --color) option.
115    5.  In pcregrep, when --colour was used with -o, the list of matching strings
116        was not coloured; this is different to GNU grep, so I have changed it to be
117        the same.
119    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
120        each matching line was coloured. Now it goes on to look for further matches
121        of any of the test patterns, which is the same behaviour as GNU grep.
123    7.  A pattern that could match an empty string could cause pcregrep to loop; it
124        doesn't make sense to accept an empty string match in pcregrep, so I have
125        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
126        seems to be how GNU grep behaves.
128    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
129        start or after a newline", because the conditional assertion was not being
130        correctly handled. The rule now is that both the assertion and what follows
131        in the first alternative must satisfy the test.
133    9.  If auto-callout was enabled in a pattern with a conditional group whose
134        condition was an assertion, PCRE could crash during matching, both with
135        pcre_exec() and pcre_dfa_exec().
137    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
138        used for matching.
140    11. Unicode property support in character classes was not working for
141        characters (bytes) greater than 127 when not in UTF-8 mode.
143    12. Added the -M command line option to pcretest.
145    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
147    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
149    16. Added comments and documentation about mis-use of no_arg in the C++
150        wrapper.
152    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
153        from Martin Jerabek that uses macro names for all relevant character and
154        string constants.
156    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
157        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
158        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
159        these, but not everybody uses configure.
161    19. A conditional group that had only one branch was not being correctly
162        recognized as an item that could match an empty string. This meant that an
163        enclosing group might also not be so recognized, causing infinite looping
164        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
165        with the subject "ab", where knowledge that the repeated group can match
166        nothing is needed in order to break the loop.
168    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
169        exec(), but without supplying a callout function, matching went wrong.
171    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
172        leak if the size of the offset vector was greater than 30. When the vector
173        is smaller, the saved offsets during recursion go onto a local stack
174        vector, but for larger vectors malloc() is used. It was failing to free
175        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
176        error, in fact).
178    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
179        heapframe that is used only when UTF-8 support is enabled. This caused no
180        problem, but was untidy.
182    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
183        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
184        included within another project.
186    24. Steven Van Ingelgem's patches to add more options to the CMake support,
187        slightly modified by me:
189          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
190              not building pcregrep.
192          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
193              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
195    25. Forward references, both numeric and by name, in patterns that made use of
196        duplicate group numbers, could behave incorrectly or give incorrect errors,
197        because when scanning forward to find the reference group, PCRE was not
198        taking into account the duplicate group numbers. A pattern such as
199        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
201    26. Changed a few more instances of "const unsigned char *" to USPTR, making
202        the feature of a custom pointer more persuasive (as requested by a user).
204    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
205        pcretest.c, inside #ifndefs, because it seems they are sometimes already
206        pre-defined.
208    28. Added support for (*UTF8) at the start of a pattern.
210    29. Arrange for flags added by the "release type" setting in CMake to be shown
211        in the configuration summary.
214    Version 7.8 05-Sep-08
215    ---------------------
217    1.  Replaced UCP searching code with optimized version as implemented for Ad
218        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
219        stage table and inline lookup instead of a function, giving speed ups of 2
220        to 5 times on some simple patterns that I tested. Permission was given to
221        distribute the MultiStage2.py script that generates the tables (it's not in
222        the tarball, but is in the Subversion repository).
224    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
225        scripts.
227    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
228        a group with a zero qualifier. The result of the study could be incorrect,
229        or the function might crash, depending on the pattern.
231    4.  Caseless matching was not working for non-ASCII characters in back
232        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
233        It now works when Unicode Property Support is available.
235    5.  In pcretest, an escape such as \x{de} in the data was always generating
236        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
237        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
238        truncation.
240    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
242    7.  Added two (int) casts to pcregrep when printing the difference of two
243        pointers, in case they are 64-bit values.
245    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
246        test 2 if it fails.
248    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
249        and a #define of that name to empty if it is not externally set. This is to
250        allow users of MSVC to set it if necessary.
252    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
253        the convenience functions in the pcre_get.c source file.
255    11. An option change at the start of a pattern that had top-level alternatives
256        could cause overwriting and/or a crash. This command provoked a crash in
257        some environments:
259          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
261        This potential security problem was recorded as CVE-2008-2371.
263    12. For a pattern where the match had to start at the beginning or immediately
264        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
265        pcre_dfa_exec() could read past the end of the passed subject if there was
266        no match. To help with detecting such bugs (e.g. with valgrind), I modified
267        pcretest so that it places the subject at the end of its malloc-ed buffer.
269    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
270        exec() might read past the end of the data buffer in UTF-8 mode.
272    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
273        the data contained the byte 0x85 as part of a UTF-8 character within its
274        first line. This applied both to normal and DFA matching.
276    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
277        /^[^d]*?$/8 failed to match "abc".
279    16. Added a missing copyright notice to pcrecpp_internal.h.
281    17. Make it more clear in the documentation that values returned from
282        pcre_exec() in ovector are byte offsets, not character counts.
284    18. Tidied a few places to stop certain compilers from issuing warnings.
286    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
287        supplied by Stefan Weber. I made a further small update for 7.8 because
288        there is a change of source arrangements: the pcre_searchfuncs.c module is
289        replaced by pcre_ucd.c.
292    Version 7.7 07-May-08
293    ---------------------
295    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
296        a string to a long long, pretend we don't even have a long long." This is
297        done by checking for the strtoq, strtoll, and _strtoi64 functions.
299    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
300        pre-7.6 versions, which defined a global no_arg variable instead of putting
301        it in the RE class. (See also #8 below.)
303    3.  Remove a line of dead code, identified by coverity and reported by Nuno
304        Lopes.
306    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
308        (1) The include/exclude patterns were being applied to the whole pathnames
309            of files, instead of just to the final components.
311        (2) If there was more than one level of directory, the subdirectories were
312            skipped unless they satisfied the include/exclude conditions. This is
313            inconsistent with GNU grep (and could even be seen as contrary to the
314            pcregrep specification - which I improved to make it absolutely clear).
315            The action now is always to scan all levels of directory, and just
316            apply the include/exclude patterns to regular files.
318    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
319        --exclude_dir in the tests to avoid scanning .svn directories.
321    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
322        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
323        doesn't support NULs in patterns.
325    7.  Added some missing "const"s to declarations of static tables in
326        pcre_compile.c and pcre_dfa_exec.c.
328    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
329        caused by fix #2  above. (Subsequently also a second patch to fix the
330        first patch. And a third patch - this was a messy problem.)
332    9.  Applied Craig's patch to remove the use of push_back().
334    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
335        matching function regexec().
337    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
338        which, however, unlike Perl's \g{...}, are subroutine calls, not back
339        references. PCRE supports relative numbers with this syntax (I don't think
340        Oniguruma does).
342    12. Previously, a group with a zero repeat such as (...){0} was completely
343        omitted from the compiled regex. However, this means that if the group
344        was called as a subroutine from elsewhere in the pattern, things went wrong
345        (an internal error was given). Such groups are now left in the compiled
346        pattern, with a new opcode that causes them to be skipped at execution
347        time.
349    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
350        to the way PCRE behaves:
352        (a) A lone ] character is dis-allowed (Perl treats it as data).
354        (b) A back reference to an unmatched subpattern matches an empty string
355            (Perl fails the current match path).
357        (c) A data ] in a character class must be notated as \] because if the
358            first data character in a class is ], it defines an empty class. (In
359            Perl it is not possible to have an empty class.) The empty class []
360            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
361            The negative empty class [^] matches any one character, independently
362            of the DOTALL setting.
364    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
365        non-existent subpattern following a character class starting with ']' and
366        containing () gave an internal compiling error instead of "reference to
367        non-existent subpattern". Fortunately, when the pattern did exist, the
368        compiled code was correct. (When scanning forwards to check for the
369        existencd of the subpattern, it was treating the data ']' as terminating
370        the class, so got the count wrong. When actually compiling, the reference
371        was subsequently set up correctly.)
373    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
374        it was being rejected as not supported by pcre_dfa_exec(), even though
375        other assertions are supported. I have made pcre_dfa_exec() support
376        (*FAIL).
378    16. The implementation of 13c above involved the invention of a new opcode,
379        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
380        cannot be changed at match time, I realized I could make a small
381        improvement to matching performance by compiling OP_ALLANY instead of
382        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
383        on the OP_ANY path.
385    17. Compiling pcretest on Windows with readline support failed without the
386        following two fixes: (1) Make the unistd.h include conditional on
387        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
389    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
390        ncurses library to be included for pcretest when ReadLine support is
391        requested, but also to allow for it to be overridden. This patch came from
392        Daniel Bergström.
394    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
395        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
396        any errors with the current Unicode tables. Thanks to Peter Kankowski for
397        spotting this.
400    Version 7.6 28-Jan-08
401    ---------------------
403    1.  A character class containing a very large number of characters with
404        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
405        overflow.
407    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
408        HAVE_LONG_LONG is not defined.
410    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
411        bring them up to date and include new features. This patch includes:
413        - Fixed PH's badly added libz and libbz2 support.
414        - Fixed a problem with static linking.
415        - Added pcredemo. [But later removed - see 7 below.]
416        - Fixed dftables problem and added an option.
417        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
418            HAVE_LONG_LONG.
419        - Added readline support for pcretest.
420        - Added an listing of the option settings after cmake has run.
422    4.  A user submitted a patch to Makefile that makes it easy to create
423        "pcre.dll" under mingw when using Configure/Make. I added stuff to
424        Makefile.am that cause it to include this special target, without
425        affecting anything else. Note that the same mingw target plus all
426        the other distribution libraries and programs are now supported
427        when configuring with CMake (see 6 below) instead of with
428        Configure/Make.
430    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
431        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
432        exported in the Windows port". It has not yet been confirmed that the patch
433        solves the problem, but it does no harm.
435    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
436        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
437        with CMake, and also correct the comment about stack recursion.
439    7.  Remove the automatic building of pcredemo from the ./configure system and
440        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
441        of a program that users should build themselves after PCRE is installed, so
442        building it automatically is not really right. What is more, it gave
443        trouble in some build environments.
445    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
448    Version 7.5 10-Jan-08
449    ---------------------
451    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
452        values in parens when parsing an RE using the C++ wrapper."
454    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
455        Characters greater than 255 were excluded from the class instead of being
456        included.
458    3.  The same bug as (2) above applied to negated POSIX classes such as
459        [:^space:].
461    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
462        defined or documented. It seems to have been a typo for PCRE_STATIC, so
463        I have changed it.
465    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
466        first named subpattern) and a construct such as (?&a) would reference the
467        first named subpattern whose name started with "a" (in other words, the
468        length check was missing). Both these problems are fixed. "Subpattern name
469        expected" is now given for (?&) (a zero-length name), and this patch also
470        makes it give the same error for \k'' (previously it complained that that
471        was a reference to a non-existent subpattern).
473    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
474        this is right because (?- can be followed by option settings as well as by
475        digits. I have, however, made the messages clearer.
477    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
478        than the number used in the conditional) now cause a compile-time error.
479        This is actually not compatible with Perl, which accepts such patterns, but
480        treats the conditional as always being FALSE (as PCRE used to), but it
481        seems to me that giving a diagnostic is better.
483    8.  Change "alphameric" to the more common word "alphanumeric" in comments
484        and messages.
486    9.  Fix two occurrences of "backslash" in comments that should have been
487        "backspace".
489    10. Remove two redundant lines of code that can never be obeyed (their function
490        was moved elsewhere).
492    11. The program that makes PCRE's Unicode character property table had a bug
493        which caused it to generate incorrect table entries for sequences of
494        characters that have the same character type, but are in different scripts.
495        It amalgamated them into a single range, with the script of the first of
496        them. In other words, some characters were in the wrong script. There were
497        thirteen such cases, affecting characters in the following ranges:
499          U+002b0 - U+002c1
500          U+0060c - U+0060d
501          U+0061e - U+00612
502          U+0064b - U+0065e
503          U+0074d - U+0076d
504          U+01800 - U+01805
505          U+01d00 - U+01d77
506          U+01d9b - U+01dbf
507          U+0200b - U+0200f
508          U+030fc - U+030fe
509          U+03260 - U+0327f
510          U+0fb46 - U+0fbb1
511          U+10450 - U+1049d
513    12. The -o option (show only the matching part of a line) for pcregrep was not
514        compatible with GNU grep in that, if there was more than one match in a
515        line, it showed only the first of them. It now behaves in the same way as
516        GNU grep.
518    13. If the -o and -v options were combined for pcregrep, it printed a blank
519        line for every non-matching line. GNU grep prints nothing, and pcregrep now
520        does the same. The return code can be used to tell if there were any
521        non-matching lines.
523    14. Added --file-offsets and --line-offsets to pcregrep.
525    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
526        infinitely looping recursion. The bug was that positive lookaheads were not
527        being skipped when checking for a possible empty match (negative lookaheads
528        and both kinds of lookbehind were skipped).
530    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
531        inclusion of <windows.h> to before rather than after the definition of
532        INVALID_FILE_ATTRIBUTES (patch from David Byron).
534    17. Specifying a possessive quantifier with a specific limit for a Unicode
535        character property caused pcre_compile() to compile bad code, which led at
536        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
537        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
538        caused the error; without that there was no problem.
540    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
542    19. Added --enable-pcretest-libreadline.
544    20. In pcrecpp.cc, the variable 'count' was incremented twice in
545        RE::GlobalReplace(). As a result, the number of replacements returned was
546        double what it should be. I removed one of the increments, but Craig sent a
547        later patch that removed the other one (the right fix) and added unit tests
548        that check the return values (which was not done before).
550    21. Several CMake things:
552        (1) Arranged that, when cmake is used on Unix, the libraries end up with
553            the names libpcre and libpcreposix, not just pcre and pcreposix.
555        (2) The above change means that pcretest and pcregrep are now correctly
556            linked with the newly-built libraries, not previously installed ones.
560    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
561        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
562        UTF-8 newline character). The key issue is that the pattern starts .*;
563        this means that the match must be either at the beginning, or after a
564        newline. The bug was in the code for advancing after a failed match and
565        checking that the new position followed a newline. It was not taking
566        account of UTF-8 characters correctly.
568    23. PCRE was behaving differently from Perl in the way it recognized POSIX
569        character classes. PCRE was not treating the sequence [:...:] as a
570        character class unless the ... were all letters. Perl, however, seems to
571        allow any characters between [: and :], though of course it rejects as
572        unknown any "names" that contain non-letters, because all the known class
573        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
574        for example, whereas PCRE did not - it did not recognize a POSIX character
575        class. This seemed a bit dangerous, so the code has been changed to be
576        closer to Perl. The behaviour is not identical to Perl, because PCRE will
577        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
578        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
579        Perl does, and where it didn't before.
581    24. Rewrite so as to remove the single use of %n from pcregrep because in some
582        Windows environments %n is disabled by default.
585    Version 7.4 21-Sep-07
586    ---------------------
588    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
589        means that a class such as [\s] counted as "explicit reference to CR or
590        LF". That isn't really right - the whole point of the change was to try to
591        help when there was an actual mention of one of the two characters. So now
592        the change happens only if \r or \n (or a literal CR or LF) character is
593        encountered.
595    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
596        of both had grown to the point where there were only 3 bits left.
597        Fortunately, there was spare space in the data structure, and so I have
598        moved the internal flags into a new 16-bit field to free up more option
599        bits.
601    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
602        but did not set the internal JCHANGED flag - either of these is enough to
603        control the way the "get" function works - but the PCRE_INFO_JCHANGED
604        facility is supposed to tell if (?J) was ever used, so now (?J) at the
605        start sets both bits.
607    4.  Added options (at build time, compile time, exec time) to change \R from
608        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
610    5.  doc/pcresyntax.html was missing from the distribution.
612    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
613        compatibility, even though it is no longer used.
615    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
616        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
617        windows.h file is present (where different names are used). [This was
618        reversed later after testing - see 16 below.]
620    8.  Changed all #include <config.h> to #include "config.h". There were also
621        some further <pcre.h> cases that I changed to "pcre.h".
623    9.  When pcregrep was used with the --colour option, it missed the line ending
624        sequence off the lines that it output.
626    10. It was pointed out to me that arrays of string pointers cause lots of
627        relocations when a shared library is dynamically loaded. A technique of
628        using a single long string with a table of offsets can drastically reduce
629        these. I have refactored PCRE in four places to do this. The result is
630        dramatic:
632          Originally:                          290
633          After changing UCP table:            187
634          After changing error message table:   43
635          After changing table of "verbs"       36
636          After changing table of Posix names   22
638        Thanks to the folks working on Gregex for glib for this insight.
640    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
641        unicode-properties was also set.
643    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
645    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
646        checked only for CRLF.
648    14. Added casts to pcretest.c to avoid compiler warnings.
650    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
652    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
653        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
654        entirely. This removes changes made in 7 above.
656    17. The CMake files have been updated, and there is now more information about
657        building with CMake in the NON-UNIX-USE document.
660    Version 7.3 28-Aug-07
661    ---------------------
663     1. In the rejigging of the build system that eventually resulted in 7.1, the
664        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
665        brackets there is not right, since it causes compilers to look for an
666        installed pcre.h, not the version that is in the source that is being
667        compiled (which of course may be different). I have changed it back to:
669          #include "pcre.h"
671        I have a vague recollection that the change was concerned with compiling in
672        different directories, but in the new build system, that is taken care of
673        by the VPATH setting the Makefile.
675     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
676        when the subject happened to end in the byte 0x85 (e.g. if the last
677        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
678        characters but of course it shouldn't be taken as a newline when it is part
679        of another character. The bug was that, for an unlimited repeat of . in
680        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
681        characters when looking for a newline.
683     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
685     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
686        in debug output.
688     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
689        long printing in the pcrecpp unittest when running under MinGW.
691     6. ESC_K was left out of the EBCDIC table.
693     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
694        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
695        limit also applies to "virtual nesting" when a pattern is recursive, and in
696        this case 1000 isn't so big. I have been able to remove this limit at the
697        expense of backing off one optimization in certain circumstances. Normally,
698        when pcre_exec() would call its internal match() function recursively and
699        immediately return the result unconditionally, it uses a "tail recursion"
700        feature to save stack. However, when a subpattern that can match an empty
701        string has an unlimited repetition quantifier, it no longer makes this
702        optimization. That gives it a stack frame in which to save the data for
703        checking that an empty string has been matched. Previously this was taken
704        from the 1000-entry workspace that had been reserved. So now there is no
705        explicit limit, but more stack is used.
707     8. Applied Daniel's patches to solve problems with the import/export magic
708        syntax that is required for Windows, and which was going wrong for the
709        pcreposix and pcrecpp parts of the library. These were overlooked when this
710        problem was solved for the main library.
712     9. There were some crude static tests to avoid integer overflow when computing
713        the size of patterns that contain repeated groups with explicit upper
714        limits. As the maximum quantifier is 65535, the maximum group length was
715        set at 30,000 so that the product of these two numbers did not overflow a
716        32-bit integer. However, it turns out that people want to use groups that
717        are longer than 30,000 bytes (though not repeat them that many times).
718        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
719        made it possible to implement the integer overflow checks in a much more
720        dynamic way, which I have now done. The artificial limitation on group
721        length has been removed - we now have only the limit on the total length of
722        the compiled pattern, which depends on the LINK_SIZE setting.
724    10. Fixed a bug in the documentation for get/copy named substring when
725        duplicate names are permitted. If none of the named substrings are set, the
726        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
727        empty string.
729    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
730        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
731        because the ] is interpreted as the first data character and the
732        terminating ] is not found. PCRE has been made compatible with Perl in this
733        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
734        cause memory overwriting.
736    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
737        string has been matched (to stop an infinite loop). It was not recognizing
738        a conditional subpattern that could match an empty string if that
739        subpattern was within another subpattern. For example, it looped when
740        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
741        condition was not nested. This bug has been fixed.
743    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
744        past the start of the subject in the presence of bytes with the top bit
745        set, for example "\x8aBCD".
747    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
748        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
750    14. Optimized (?!) to (*FAIL).
752    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
753        This restricts code points to be within the range 0 to 0x10FFFF, excluding
754        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
755        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
756        does: it's just the validity check that is more restrictive.
758    16. Inserted checks for integer overflows during escape sequence (backslash)
759        processing, and also fixed erroneous offset values for syntax errors during
760        backslash processing.
762    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
763        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
765    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
766        caused an overrun.
768    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
769        something other than just ASCII characters) inside a group that had an
770        unlimited repeat caused a loop at compile time (while checking to see
771        whether the group could match an empty string).
773    20. Debugging a pattern containing \p or \P could cause a crash. For example,
774        [\P{Any}] did so. (Error in the code for printing property names.)
776    21. An orphan \E inside a character class could cause a crash.
778    22. A repeated capturing bracket such as (A)? could cause a wild memory
779        reference during compilation.
781    23. There are several functions in pcre_compile() that scan along a compiled
782        expression for various reasons (e.g. to see if it's fixed length for look
783        behind). There were bugs in these functions when a repeated \p or \P was
784        present in the pattern. These operators have additional parameters compared
785        with \d, etc, and these were not being taken into account when moving along
786        the compiled data. Specifically:
788        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
789            length.
791        (b) An item such as \pL+ within a repeated group could cause crashes or
792            loops.
794        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
795            "reference to non-existent subpattern" error.
797        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
799    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
800        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
802    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
804    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
805        character were causing crashes (broken optimization).
807    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
808        \p or \P) caused a compile-time loop.
810    28. More problems have arisen in unanchored patterns when CRLF is a valid line
811        break. For example, the unstudied pattern [\r\n]A does not match the string
812        "\r\nA" because change 7.0/46 below moves the current point on by two
813        characters after failing to match at the start. However, the pattern \nA
814        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
815        the same is true. There doesn't seem any very clean way out of this, but
816        what I have chosen to do makes the common cases work: PCRE now takes note
817        of whether there can be an explicit match for \r or \n anywhere in the
818        pattern, and if so, 7.0/46 no longer applies. As part of this change,
819        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
820        pattern has explicit CR or LF references.
822    29. Added (*CR) etc for changing newline setting at start of pattern.
825    Version 7.2 19-Jun-07
826    ---------------------
828     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
829        which is apparently normally available under Windows.
831     2. Re-jig the pcregrep tests with different newline settings in an attempt
832        to make them independent of the local environment's newline setting.
834     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
836     4. Some of the "internals" tests were previously cut out when the link size
837        was not 2, because the output contained actual offsets. The recent new
838        "Z" feature of pcretest means that these can be cut out, making the tests
839        usable with all link sizes.
841     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
842        stack recursion. This gives a massive performance boost under BSD, but just
843        a small improvement under Linux. However, it saves one field in the frame
844        in all cases.
846     6. Added more features from the forthcoming Perl 5.10:
848        (a) (?-n) (where n is a string of digits) is a relative subroutine or
849            recursion call. It refers to the nth most recently opened parentheses.
851        (b) (?+n) is also a relative subroutine call; it refers to the nth next
852            to be opened parentheses.
854        (c) Conditions that refer to capturing parentheses can be specified
855            relatively, for example, (?(-2)... or (?(+3)...
857        (d) \K resets the start of the current match so that everything before
858            is not part of it.
860        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
862        (f) \g{name} is another synonym - part of Perl 5.10's unification of
863            reference syntax.
865        (g) (?| introduces a group in which the numbering of parentheses in each
866            alternative starts with the same number.
868        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
870     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
873     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
874        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
875        for detecting groups that can match an empty string.
877     9. A pattern with a very large number of alternatives (more than several
878        hundred) was running out of internal workspace during the pre-compile
879        phase, where pcre_compile() figures out how much memory will be needed. A
880        bit of new cunning has reduced the workspace needed for groups with
881        alternatives. The 1000-alternative test pattern now uses 12 bytes of
882        workspace instead of running out of the 4096 that are available.
884    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
886    11. Applied patch from Google to remove an optimization that didn't quite work.
887        The report of the bug said:
889          pcrecpp::RE("a*").FullMatch("aaa") matches, while
890          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
891          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
893    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
894        it matched the wrong number of bytes.
897    Version 7.1 24-Apr-07
898    ---------------------
900     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
901        that is more "standard", making use of automake and other Autotools. There
902        is some re-arrangement of the files and adjustment of comments consequent
903        on this.
905     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
906        for recursive directory scanning broke on some systems because the files
907        are not scanned in any specific order and on different systems the order
908        was different. A call to "sort" has been inserted into RunGrepTest for the
909        approprate test as a short-term fix. In the longer term there may be an
910        alternative.
912     3. I had an email from Eric Raymond about problems translating some of PCRE's
913        man pages to HTML (despite the fact that I distribute HTML pages, some
914        people do their own conversions for various reasons). The problems
915        concerned the use of low-level troff macros .br and .in. I have therefore
916        removed all such uses from the man pages (some were redundant, some could
917        be replaced by .nf/.fi pairs). The 132html script that I use to generate
918        HTML has been updated to handle .nf/.fi and to complain if it encounters
919        .br or .in.
921     4. Updated comments in configure.ac that get placed in config.h.in and also
922        arranged for config.h to be included in the distribution, with the name
923        config.h.generic, for the benefit of those who have to compile without
924        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
926     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
927        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
928        makevp.bat for the current PCRE, using the additional files
929        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
931     6. A Windows user reported a minor discrepancy with test 2, which turned out
932        to be caused by a trailing space on an input line that had got lost in his
933        copy. The trailing space was an accident, so I've just removed it.
935     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
936        that is needed.
938     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
939        as "const" (a) because they are and (b) because it helps the PHP
940        maintainers who have recently made a script to detect big data structures
941        in the php code that should be moved to the .rodata section. I remembered
942        to update Builducptable as well, so it won't revert if ucptable.h is ever
943        re-created.
945     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
946        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
947        order to be able to cut out the UTF-8 tables in the latter when UTF-8
948        support is not required. This saves 1.5-2K of code, which is important in
949        some applications.
951        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
952        so as not to refer to the tables, even though these functions will never be
953        called when UTF-8 support is disabled. Otherwise there are problems with a
954        shared library.
956    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
958        (a) It was defining its arguments as char * instead of void *.
960        (b) It was assuming that all moves were upwards in memory; this was true
961            a long time ago when I wrote it, but is no longer the case.
963        The emulated memove() is provided for those environments that have neither
964        memmove() nor bcopy(). I didn't think anyone used it these days, but that
965        is clearly not the case, as these two bugs were recently reported.
967    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
968        and Detrail to create the HTML documentation, the .txt form of the man
969        pages, and it removes trailing spaces from listed files. It also creates
970        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
971        case, it wraps all the #defines with #ifndefs. This script should be run
972        before "make dist".
974    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
975        with Unicode property support.
977        (a) For a maximizing quantifier, if the two different cases of the
978            character were of different lengths in their UTF-8 codings (there are
979            some cases like this - I found 11), and the matching function had to
980            back up over a mixture of the two cases, it incorrectly assumed they
981            were both the same length.
983        (b) When PCRE was configured to use the heap rather than the stack for
984            recursion during matching, it was not correctly preserving the data for
985            the other case of a UTF-8 character when checking ahead for a match
986            while processing a minimizing repeat. If the check also involved
987            matching a wide character, but failed, corruption could cause an
988            erroneous result when trying to check for a repeat of the original
989            character.
991    13. Some tidying changes to the testing mechanism:
993        (a) The RunTest script now detects the internal link size and whether there
994            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
995            values substituted by "configure". (The RunGrepTest script already did
996            this for UTF-8.) The configure.ac script no longer substitutes the
997            relevant variables.
999        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1000            with length and offset values. This means that the output is different
1001            for different internal link sizes. Test 2 is skipped for link sizes
1002            other than 2 because of this, bypassing the problem. Unfortunately,
1003            there was also a test in test 3 (the locale tests) that used /B and
1004            failed for link sizes other than 2. Rather than cut the whole test out,
1005            I have added a new /Z option to pcretest that replaces the length and
1006            offset values with spaces. This is now used to make test 3 independent
1007            of link size. (Test 2 will be tidied up later.)
1009    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1010        segmentation fault instead of returning the appropriate error message.
1012    15. In multiline mode when the newline sequence was set to "any", the pattern
1013        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1014        This doesn't seem right; it now treats the CRLF combination as the line
1015        ending, and so does not match in that case. It's only a pattern such as ^$
1016        that would hit this one: something like ^ABC$ would have failed after \r
1017        and then tried again after \r\n.
1019    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1020        in an attempt to make files that differ only in their line terminators
1021        compare equal. This works on Linux.
1023    17. Under certain error circumstances pcregrep might try to free random memory
1024        as it exited. This is now fixed, thanks to valgrind.
1026    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1027        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1028        was because its rules for how to advance for /g after matching an empty
1029        string at the end of a line did not allow for this case. They now check for
1030        it specially.
1032    20. pcretest is supposed to handle patterns and data of any length, by
1033        extending its buffers when necessary. It was getting this wrong when the
1034        buffer for a data line had to be extended.
1036    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1037        CRLF as a newline sequence.
1039    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1040        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1041        I have nevertheless tidied it up.
1043    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1045    24. Added a man page for pcre-config.
1048    Version 7.0 19-Dec-06
1049    ---------------------
1051     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1052        moving to gcc 4.1.1.
1054     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1055        sys/time.h, which is documented as needed for this function. It doesn't
1056        seem to matter on Linux, but it showed up on some releases of OS X.
1058     3. It seems that there are systems where bytes whose values are greater than
1059        127 match isprint() in the "C" locale. The "C" locale should be the
1060        default when a C program starts up. In most systems, only ASCII printing
1061        characters match isprint(). This difference caused the output from pcretest
1062        to vary, making some of the tests fail. I have changed pcretest so that:
1064        (a) When it is outputting text in the compiled version of a pattern, bytes
1065            other than 32-126 are always shown as hex escapes.
1067        (b) When it is outputting text that is a matched part of a subject string,
1068            it does the same, unless a different locale has been set for the match
1069            (using the /L modifier). In this case, it uses isprint() to decide.
1071     4. Fixed a major bug that caused incorrect computation of the amount of memory
1072        required for a compiled pattern when options that changed within the
1073        pattern affected the logic of the preliminary scan that determines the
1074        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1075        that the computed length was too small. The symptoms of this bug were
1076        either the PCRE error "internal error: code overflow" from pcre_compile(),
1077        or a glibc crash with a message such as "pcretest: free(): invalid next
1078        size (fast)". Examples of patterns that provoked this bug (shown in
1079        pcretest format) are:
1081          /(?-x: )/x
1082          /(?x)(?-x: \s*#\s*)/
1083          /((?i)[\x{c0}])/8
1084          /(?i:[\x{c0}])/8
1086        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1087        is now done differently.
1089     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1090        wrapper classes; (b) implement a new function in the C++ scanner that is
1091        more efficient than the old way of doing things because it avoids levels of
1092        recursion in the regex matching; (c) add a paragraph to the documentation
1093        for the FullMatch() function.
1095     6. The escape sequence \n was being treated as whatever was defined as
1096        "newline". Not only was this contrary to the documentation, which states
1097        that \n is character 10 (hex 0A), but it also went horribly wrong when
1098        "newline" was defined as CRLF. This has been fixed.
1100     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1101        was being set to -1 for the "end of line" case (supposedly a value that no
1102        character can have). Though this value is never used (the check for end of
1103        line is "zero bytes in current character"), it caused compiler complaints.
1104        I've changed it to 0xffffffff.
1106     8. In pcre_version.c, the version string was being built by a sequence of
1107        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1108        string (as it is for production releases) called a macro with an empty
1109        argument. The C standard says the result of this is undefined. The gcc
1110        compiler treats it as an empty string (which was what was wanted) but it is
1111        reported that Visual C gives an error. The source has been hacked around to
1112        avoid this problem.
1114     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1115        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1116        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1117        of them did).
1119    10. Originally, pcretest opened its input and output without "b"; then I was
1120        told that "b" was needed in some environments, so it was added for release
1121        5.0 to both the input and output. (It makes no difference on Unix-like
1122        systems.) Later I was told that it is wrong for the input on Windows. I've
1123        now abstracted the modes into two macros, to make it easier to fiddle with
1124        them, and removed "b" from the input mode under Windows.
1126    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1128    12. Added -help and --help to pcretest as an official way of being reminded
1129        of the options.
1131    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1132        and pcrecpp.cc because they annoy compilers at high warning levels.
1134    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1136    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1137        scripts are not C programs :-) and which was not noticed because it works
1138        on Linux.
1140    16. pcretest is supposed to handle any length of pattern and data line (as one
1141        line or as a continued sequence of lines) by extending its input buffer if
1142        necessary. This feature was broken for very long pattern lines, leading to
1143        a string of junk being passed to pcre_compile() if the pattern was longer
1144        than about 50K.
1146    17. I have done a major re-factoring of the way pcre_compile() computes the
1147        amount of memory needed for a compiled pattern. Previously, there was code
1148        that made a preliminary scan of the pattern in order to do this. That was
1149        OK when PCRE was new, but as the facilities have expanded, it has become
1150        harder and harder to keep it in step with the real compile phase, and there
1151        have been a number of bugs (see for example, 4 above). I have now found a
1152        cunning way of running the real compile function in a "fake" mode that
1153        enables it to compute how much memory it would need, while actually only
1154        ever using a few hundred bytes of working memory and without too many
1155        tests of the mode. This should make future maintenance and development
1156        easier. A side effect of this work is that the limit of 200 on the nesting
1157        depth of parentheses has been removed (though this was never a serious
1158        limitation, I suspect). However, there is a downside: pcre_compile() now
1159        runs more slowly than before (30% or more, depending on the pattern). I
1160        hope this isn't a big issue. There is no effect on runtime performance.
1162    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1163        newline (only possible for the last line of a file) and it was a
1164        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1166    19. Added additional timing features to pcretest. (1) The -tm option now times
1167        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1168        separate command line item, by a number that specifies the number of
1169        repeats to use when timing. The default is 50000; this gives better
1170        precision, but takes uncomfortably long for very large patterns.
1172    20. Extended pcre_study() to be more clever in cases where a branch of a
1173        subpattern has no definite first character. For example, (a*|b*)[cd] would
1174        previously give no result from pcre_study(). Now it recognizes that the
1175        first character must be a, b, c, or d.
1177    21. There was an incorrect error "recursive call could loop indefinitely" if
1178        a subpattern (or the entire pattern) that was being tested for matching an
1179        empty string contained only one non-empty item after a nested subpattern.
1180        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1181        incorrectly, because the \d was being skipped in the check.
1183    22. The pcretest program now has a new pattern option /B and a command line
1184        option -b, which is equivalent to adding /B to every pattern. This causes
1185        it to show the compiled bytecode, without the additional information that
1186        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1187        is the same as /B/I).
1189    23. A new optimization is now able automatically to treat some sequences such
1190        as a*b as a*+b. More specifically, if something simple (such as a character
1191        or a simple class like \d) has an unlimited quantifier, and is followed by
1192        something that cannot possibly match the quantified thing, the quantifier
1193        is automatically "possessified".
1195    24. A recursive reference to a subpattern whose number was greater than 39
1196        went wrong under certain circumstances in UTF-8 mode. This bug could also
1197        have affected the operation of pcre_study().
1199    25. Realized that a little bit of performance could be had by replacing
1200        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1202    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1204    27. Possessive quantifiers such as a++ were previously implemented by turning
1205        them into atomic groups such as ($>a+). Now they have their own opcodes,
1206        which improves performance. This includes the automatically created ones
1207        from 23 above.
1209    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1210        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1211        the first matched character to be a colon. This applied both to named and
1212        numbered groups.
1214    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1216    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1217        building PCRE on Windows easier, so I have included it in the distribution.
1219    31. There is now a check in pcretest against a ridiculously large number being
1220        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1221        loop, the loop is abandoned.
1223    32. Forward references to subpatterns in conditions such as (?(2)...) where
1224        subpattern 2 is defined later cause pcre_compile() to search forwards in
1225        the pattern for the relevant set of parentheses. This search went wrong
1226        when there were unescaped parentheses in a character class, parentheses
1227        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1229    33. "Subroutine" calls and backreferences were previously restricted to
1230        referencing subpatterns earlier in the regex. This restriction has now
1231        been removed.
1233    34. Added a number of extra features that are going to be in Perl 5.10. On the
1234        whole, these are just syntactic alternatives for features that PCRE had
1235        previously implemented using the Python syntax or my own invention. The
1236        other formats are all retained for compatibility.
1238        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1239            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1240            also .NET compatible.
1242        (b) A recursion or subroutine call to a named group can now be defined as
1243            (?&name) as well as (?P>name).
1245        (c) A backreference to a named group can now be defined as \k<name> or
1246            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1247            5.10, are also .NET compatible.
1249        (d) A conditional reference to a named group can now use the syntax
1250            (?(<name>) or (?('name') as well as (?(name).
1252        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1253            groups (named and numbered) that are never evaluated inline, but can be
1254            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1255            is always false. There may be only one alternative in such a group.
1257        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1258            as the simple (?(R). The condition is true only if the most recent
1259            recursion is that of the given number or name. It does not search out
1260            through the entire recursion stack.
1262        (g) The escape \gN or \g{N} has been added, where N is a positive or
1263            negative number, specifying an absolute or relative reference.
1265    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1266        some "unreachable code" warnings.
1268    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1269        things, this adds five new scripts.
1271    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1272        There were also incompatibilities regarding the handling of \Q..\E inside
1273        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1274        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1276    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1277        matches an empty string, and forcibly breaks the loop. There were bugs in
1278        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1279        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1280        separate and independent bugs (that affected different cases) have been
1281        fixed.
1283    39. Refactored the code to abolish the use of different opcodes for small
1284        capturing bracket numbers. This is a tidy that I avoided doing when I
1285        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1286        The new approach is not only tidier, it makes it possible to reduce the
1287        memory needed to fix the previous bug (38).
1289    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1290        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1291        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1292        mode.
1294    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1295        report.
1297    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1298        copy construction and assignment in the C++ wrapper.
1300    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1301        couple of bugs that could have given wrong results in the "--newline=crlf"
1302        case.
1304    44. Added a number of casts and did some reorganization of signed/unsigned int
1305        variables following suggestions from Dair Grant. Also renamed the variable
1306        "this" as "item" because it is a C++ keyword.
1308    45. Arranged for dftables to add
1310          #include "pcre_internal.h"
1312        to pcre_chartables.c because without it, gcc 4.x may remove the array
1313        definition from the final binary if PCRE is built into a static library and
1314        dead code stripping is activated.
1316    46. For an unanchored pattern, if a match attempt fails at the start of a
1317        newline sequence, and the newline setting is CRLF or ANY, and the next two
1318        characters are CRLF, advance by two characters instead of one.
1321    Version 6.7 04-Jul-06
1322    ---------------------
1324     1. In order to handle tests when input lines are enormously long, pcretest has
1325        been re-factored so that it automatically extends its buffers when
1326        necessary. The code is crude, but this _is_ just a test program. The
1327        default size has been increased from 32K to 50K.
1329     2. The code in pcre_study() was using the value of the re argument before
1330        testing it for NULL. (Of course, in any sensible call of the function, it
1331        won't be NULL.)
1333     3. The memmove() emulation function in pcre_internal.h, which is used on
1334        systems that lack both memmove() and bcopy() - that is, hardly ever -
1335        was missing a "static" storage class specifier.
1337     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1338        containing an extended class (one that cannot be represented by a bitmap
1339        because it contains high-valued characters or Unicode property items, e.g.
1340        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1341        pattern, but PCRE should not loop if you do not (it no longer does).
1342        [Detail: two cases were found: (a) a repeated subpattern containing an
1343        extended class; (b) a recursive reference to a subpattern that followed a
1344        previous extended class. It wasn't skipping over the extended class
1345        correctly when UTF-8 mode was not set.]
1347     5. A negated single-character class was not being recognized as fixed-length
1348        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1349        compile error "lookbehind assertion is not fixed length".
1351     6. The RunPerlTest auxiliary script was showing an unexpected difference
1352        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1353        write a Perl script that can interpret lines of an input file either as
1354        byte characters or as UTF-8, which is what "perltest" was being required to
1355        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1356        can't do is switch easily at run time between having the "use utf8;" pragma
1357        or not. In the end, I fudged it by using the RunPerlTest script to insert
1358        "use utf8;" explicitly for the UTF-8 tests.
1360     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1361        the end of the subject string, contrary to the documentation and to what
1362        Perl does. This was true of both matching functions. Now it matches only at
1363        the start of the subject and immediately after *internal* newlines.
1365     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1366        a pointer to an int instead of a pointer to an unsigned long int. This
1367        caused problems on 64-bit systems.
1369     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1370        instance of the 'standard' template library not being so standard".
1372    10. There was no check on the number of named subpatterns nor the maximum
1373        length of a subpattern name. The product of these values is used to compute
1374        the size of the memory block for a compiled pattern. By supplying a very
1375        long subpattern name and a large number of named subpatterns, the size
1376        computation could be caused to overflow. This is now prevented by limiting
1377        the length of names to 32 characters, and the number of named subpatterns
1378        to 10,000.
1380    11. Subpatterns that are repeated with specific counts have to be replicated in
1381        the compiled pattern. The size of memory for this was computed from the
1382        length of the subpattern and the repeat count. The latter is limited to
1383        65535, but there was no limit on the former, meaning that integer overflow
1384        could in principle occur. The compiled length of a repeated subpattern is
1385        now limited to 30,000 bytes in order to prevent this.
1387    12. Added the optional facility to have named substrings with the same name.
1389    13. Added the ability to use a named substring as a condition, using the
1390        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1391        are numbers (not recommended). Forward references are permitted.
1393    14. Added forward references in named backreferences (if you see what I mean).
1395    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1396        pattern could run off the end of the subject. For example, the pattern
1397        "(?s)(.{1,5})"8 did this with the subject "ab".
1399    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1400        PCRE_CASELESS was set when matching characters that were quantified with ?
1401        or *.
1403    17. A character class other than a single negated character that had a minimum
1404        but no maximum quantifier - for example [ab]{6,} - was not handled
1405        correctly by pce_dfa_exec(). It would match only one character.
1407    18. A valid (though odd) pattern that looked like a POSIX character
1408        class but used an invalid character after [ (for example [[,abc,]]) caused
1409        pcre_compile() to give the error "Failed: internal error: code overflow" or
1410        in some cases to crash with a glibc free() error. This could even happen if
1411        the pattern terminated after [[ but there just happened to be a sequence of
1412        letters, a binary zero, and a closing ] in the memory that followed.
1414    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1415        over the years. Originally (before any Unicode support), just the bottom 8
1416        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1417        output from "man perlunicode" includes this:
1419          The regular expression compiler produces polymorphic opcodes.  That
1420          is, the pattern adapts to the data and automatically switches to
1421          the Unicode character scheme when presented with Unicode data--or
1422          instead uses a traditional byte scheme when presented with byte
1423          data.
1425        Sadly, a wide octal escape does not cause a switch, and in a string with
1426        no other multibyte characters, these octal escapes are treated as before.
1427        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1428        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1429        Unicode string.
1431        I have not perpetrated such confusion in PCRE. Up till now, it took just
1432        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1433        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1434        translate to the appropriate multibyte character.
1436    29. Applied some refactoring to reduce the number of warnings from Microsoft
1437        and Borland compilers. This has included removing the fudge introduced
1438        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1439        a warning about an unused variable.
1441    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1442        characters since release 4.0, because Perl (from release 5.004) does not.
1443        [Or at least, is documented not to: some releases seem to be in conflict
1444        with the documentation.] However, when a pattern was studied with
1445        pcre_study() and all its branches started with \s, PCRE still included VT
1446        as a possible starting character. Of course, this did no harm; it just
1447        caused an unnecessary match attempt.
1449    22. Removed a now-redundant internal flag bit that recorded the fact that case
1450        dependency changed within the pattern. This was once needed for "required
1451        byte" processing, but is no longer used. This recovers a now-scarce options
1452        bit. Also moved the least significant internal flag bit to the most-
1453        significant bit of the word, which was not previously used (hangover from
1454        the days when it was an int rather than a uint) to free up another bit for
1455        the future.
1457    23. Added support for CRLF line endings as well as CR and LF. As well as the
1458        default being selectable at build time, it can now be changed at runtime
1459        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1460        specify that it is scanning data with non-default line endings.
1462    24. Changed the definition of CXXLINK to make it agree with the definition of
1463        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1465    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1466        recursions. This makes a big different to stack usage for some patterns.
1468    26. If a subpattern containing a named recursion or subroutine reference such
1469        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1470        the space required for the compiled pattern went wrong and gave too small a
1471        value. Depending on the environment, this could lead to "Failed: internal
1472        error: code overflow at offset 49" or "glibc detected double free or
1473        corruption" errors.
1475    27. Applied patches from Google (a) to support the new newline modes and (b) to
1476        advance over multibyte UTF-8 characters in GlobalReplace.
1478    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1479        difference for some implementation of PCRE in some Windows version.
1481    29. Added some extra testing facilities to pcretest:
1483        \q<number>   in a data line sets the "match limit" value
1484        \Q<number>   in a data line sets the "match recursion limt" value
1485        -S <number>  sets the stack size, where <number> is in megabytes
1487        The -S option isn't available for Windows.
1490    Version 6.6 06-Feb-06
1491    ---------------------
1493     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1494        in pcreposix.h. I have copied the definition from pcre.h.
1496     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1497        because pcre.h is no longer a built file.
1499     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1500        not normally included in the compiled code.
1503    Version 6.5 01-Feb-06
1504    ---------------------
1506     1. When using the partial match feature with pcre_dfa_exec(), it was not
1507        anchoring the second and subsequent partial matches at the new starting
1508        point. This could lead to incorrect results. For example, with the pattern
1509        /1234/, partially matching against "123" and then "a4" gave a match.
1511     2. Changes to pcregrep:
1513        (a) All non-match returns from pcre_exec() were being treated as failures
1514            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1515            error message is output. Some extra information is given for the
1516            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1517            probably the only errors that are likely to be caused by users (by
1518            specifying a regex that has nested indefinite repeats, for instance).
1519            If there are more than 20 of these errors, pcregrep is abandoned.
1521        (b) A binary zero was treated as data while matching, but terminated the
1522            output line if it was written out. This has been fixed: binary zeroes
1523            are now no different to any other data bytes.
1525        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1526            used to set a locale for matching. The --locale=xxxx long option has
1527            been added (no short equivalent) to specify a locale explicitly on the
1528            pcregrep command, overriding the environment variables.
1530        (d) When -B was used with -n, some line numbers in the output were one less
1531            than they should have been.
1533        (e) Added the -o (--only-matching) option.
1535        (f) If -A or -C was used with -c (count only), some lines of context were
1536            accidentally printed for the final match.
1538        (g) Added the -H (--with-filename) option.
1540        (h) The combination of options -rh failed to suppress file names for files
1541            that were found from directory arguments.
1543        (i) Added the -D (--devices) and -d (--directories) options.
1545        (j) Added the -F (--fixed-strings) option.
1547        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1549        (l) Added the --colo(u)r option.
1551        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1552            is not present by default.
1554     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1555        items such as (?R) or (?1), when the recursion could match a number of
1556        alternatives. If it matched one of the alternatives, but subsequently,
1557        outside the recursion, there was a failure, the code tried to back up into
1558        the recursion. However, because of the way PCRE is implemented, this is not
1559        possible, and the result was an incorrect result from the match.
1561        In order to prevent this happening, the specification of recursion has
1562        been changed so that all such subpatterns are automatically treated as
1563        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1565     4. I had overlooked the fact that, in some locales, there are characters for
1566        which isalpha() is true but neither isupper() nor islower() are true. In
1567        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1568        and ordfeminine) are like this. This affected the treatment of \w and \W
1569        when they appeared in character classes, but not when they appeared outside
1570        a character class. The bit map for "word" characters is now created
1571        separately from the results of isalnum() instead of just taking it from the
1572        upper, lower, and digit maps. (Plus the underscore character, of course.)
1574     5. The above bug also affected the handling of POSIX character classes such as
1575        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1576        permanent tables. Instead, the bit maps for such a class were previously
1577        created as the appropriate unions of the upper, lower, and digit bitmaps.
1578        Now they are created by subtraction from the [[:word:]] class, which has
1579        its own bitmap.
1581     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1582        It is created by subtracting the vertical space characters (\x09, \x0a,
1583        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1584        subtraction was done in the overall bitmap for a character class, meaning
1585        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1586        be recognized. This bug has been fixed.
1588     7. Patches from the folks at Google:
1590          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1591          real life, but is still worth protecting against".
1593          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1594          regular expressions".
1596          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1597          have it.
1599          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1600          "configure" and the latter not, in order to fix a problem somebody had
1601          with compiling the Arg class on HP-UX.
1603          (e) Improve the error-handling of the C++ wrapper a little bit.
1605          (f) New tests for checking recursion limiting.
1607     8. The pcre_memmove() function, which is used only if the environment does not
1608        have a standard memmove() function (and is therefore rarely compiled),
1609        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1610        returning a result (though PCRE never actually uses the result).
1612     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1613        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1614        returned instead of calling malloc() with an overflowing number that would
1615        most likely cause subsequent chaos.
1617    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1619    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1620        with this option is matched, the nmatch and pmatch options of regexec() are
1621        ignored.
1623    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1624        provided in case anyone wants to the the POSIX interface with UTF-8
1625        strings.
1627    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1628        C++ linking (needed for some HP-UX environments).
1630    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1631        (unused parameter) and in the pcre_printint() function (omitted "default"
1632        switch label when the default is to do nothing).
1634    15. Added some code to make it possible, when PCRE is compiled as a C++
1635        library, to replace subject pointers for pcre_exec() with a smart pointer
1636        class, thus making it possible to process discontinuous strings.
1638    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1639        much the same function. They were added by different people who were trying
1640        to make PCRE easy to compile on non-Unix systems. It has been suggested
1641        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1642        for compiling on Windows systems. I have therefore replaced it with
1643        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1644        defaults to "extern" for C or "extern C" for C++, which works fine on
1645        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1646        SCOPE with something explicit in config.h. In addition:
1648        (a) pcreposix.h still had just "extern" instead of either of these macros;
1649            I have replaced it with PCRE_DATA_SCOPE.
1651        (b) Functions such as _pcre_xclass(), which are internal to the library,
1652            but external in the C sense, all had PCRE_EXPORT in their definitions.
1653            This is apparently wrong for the Windows case, so I have removed it.
1654            (It makes no difference on Unix-like systems.)
1656    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1657        of recursive calls to match(). This is different to MATCH_LIMIT because
1658        that limits the total number of calls to match(), not all of which increase
1659        the depth of recursion. Limiting the recursion depth limits the amount of
1660        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1661        when PCRE is compiled, and changed at run time. A patch from Google adds
1662        this functionality to the C++ interface.
1664    18. Changes to the handling of Unicode character properties:
1666        (a) Updated the table to Unicode 4.1.0.
1668        (b) Recognize characters that are not in the table as "Cn" (undefined).
1670        (c) I revised the way the table is implemented to a much improved format
1671            which includes recognition of ranges. It now supports the ranges that
1672            are defined in UnicodeData.txt, and it also amalgamates other
1673            characters into ranges. This has reduced the number of entries in the
1674            table from around 16,000 to around 3,000, thus reducing its size
1675            considerably. I realized I did not need to use a tree structure after
1676            all - a binary chop search is just as efficient. Having reduced the
1677            number of entries, I extended their size from 6 bytes to 8 bytes to
1678            allow for more data.
1680        (d) Added support for Unicode script names via properties such as \p{Han}.
1682    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1683        matching that character.
1685    20. When matching a repeated Unicode property with a minimum greater than zero,
1686        (for example \pL{2,}), PCRE could look past the end of the subject if it
1687        reached it while seeking the minimum number of characters. This could
1688        happen only if some of the characters were more than one byte long, because
1689        there is a check for at least the minimum number of bytes.
1691    21. Refactored the implementation of \p and \P so as to be more general, to
1692        allow for more different types of property in future. This has changed the
1693        compiled form incompatibly. Anybody with saved compiled patterns that use
1694        \p or \P will have to recompile them.
1696    22. Added "Any" and "L&" to the supported property types.
1698    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1699        but give a compile time error if the value is greater than 0xff.
1701    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1702        accidentally not being installed or uninstalled.
1704    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1705        made were to insert the current release number. This seemed silly, because
1706        it made things harder for people building PCRE on systems that don't run
1707        "configure". I have turned pcre.h into a distributed file, no longer built
1708        by "configure", with the version identification directly included. There is
1709        no longer a pcre.h.in file.
1711        However, this change necessitated a change to the pcre-config script as
1712        well. It is built from pcre-config.in, and one of the substitutions was the
1713        release number. I have updated configure.ac so that ./configure now finds
1714        the release number by grepping pcre.h.
1716    26. Added the ability to run the tests under valgrind.
1719    Version 6.4 05-Sep-05
1720    ---------------------
1722     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1723        "--" to be printed when multiple files were scanned, even when none of the
1724        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1725        consider it to be a bug, and have restored the previous behaviour.
1727     2. A couple of code tidies to get rid of compiler warnings.
1729     3. The pcretest program used to cheat by referring to symbols in the library
1730        whose names begin with _pcre_. These are internal symbols that are not
1731        really supposed to be visible externally, and in some environments it is
1732        possible to suppress them. The cheating is now confined to including
1733        certain files from the library's source, which is a bit cleaner.
1735     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1736        file's purpose clearer.
1738     5. Reorganized pcre_ucp_findchar().
1741    Version 6.3 15-Aug-05
1742    ---------------------
1744     1. The file libpcre.pc.in did not have general read permission in the tarball.
1746     2. There were some problems when building without C++ support:
1748        (a) If C++ support was not built, "make install" and "make test" still
1749            tried to test it.
1751        (b) There were problems when the value of CXX was explicitly set. Some
1752            changes have been made to try to fix these, and ...
1754        (c) --disable-cpp can now be used to explicitly disable C++ support.
1756        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1757            backslash in a target when C++ was disabled. This confuses some
1758            versions of "make", apparently. Using an intermediate variable solves
1759            this. (Same for CPP_LOBJ.)
1761     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1762        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1763        necessary on certain architectures.
1765     4. Added a setting of -export-symbols-regex to the link command to remove
1766        those symbols that are exported in the C sense, but actually are local
1767        within the library, and not documented. Their names all begin with
1768        "_pcre_". This is not a perfect job, because (a) we have to except some
1769        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1770        available (and never for static libraries). I have made a note to try to
1771        find a way round (a) in the future.
1774    Version 6.2 01-Aug-05
1775    ---------------------
1777     1. There was no test for integer overflow of quantifier values. A construction
1778        such as {1111111111111111} would give undefined results. What is worse, if
1779        a minimum quantifier for a parenthesized subpattern overflowed and became
1780        negative, the calculation of the memory size went wrong. This could have
1781        led to memory overwriting.
1783     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1785     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1786        operating environments where this matters.
1788     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1789        PCRE options from within the C++ wrapper.
1791     5. Named capturing subpatterns were not being correctly counted when a pattern
1792        was compiled. This caused two problems: (a) If there were more than 100
1793        such subpatterns, the calculation of the memory needed for the whole
1794        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1795        back references of the form \12, where the number was greater than 9, were
1796        not recognized as back references, even though there were sufficient
1797        previous subpatterns.
1799     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1800        versions of gcc, e.g. 2.95.4.
1803    Version 6.1 21-Jun-05
1804    ---------------------
1806     1. There was one reference to the variable "posix" in pcretest.c that was not
1807        surrounded by "#if !defined NOPOSIX".
1809     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1810        the cross-check on the old pcre_info() function, for the benefit of the
1811        cut-down version of PCRE that is currently imported into Exim.
1813     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1814        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1815        patterns that start (?i) but I don't think that matters. The use of (?i) is
1816        just an example; this all applies to the other options as well.
1818     4. Since libtool seems to echo the compile commands it is issuing, the output
1819        from "make" can be reduced a bit by putting "@" in front of each libtool
1820        compile command.
1822     5. Patch from the folks at Google for configure.in to be a bit more thorough
1823        in checking for a suitable C++ installation before trying to compile the
1824        C++ stuff. This should fix a reported problem when a compiler was present,
1825        but no suitable headers.
1827     6. The man pages all had just "PCRE" as their title. I have changed them to
1828        be the relevant file name. I have also arranged that these names are
1829        retained in the file doc/pcre.txt, which is a concatenation in text format
1830        of all the man pages except the little individual ones for each function.
1832     7. The NON-UNIX-USE file had not been updated for the different set of source
1833        files that come with release 6. I also added a few comments about the C++
1834        wrapper.
1837    Version 6.0 07-Jun-05
1838    ---------------------
1840     1. Some minor internal re-organization to help with my DFA experiments.
1842     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1843        didn't matter for the library itself when fully configured, but did matter
1844        when compiling without UCP support, or within Exim, where the ucp files are
1845        not imported.
1847     3. Refactoring of the library code to split up the various functions into
1848        different source modules. The addition of the new DFA matching code (see
1849        below) to a single monolithic source would have made it really too
1850        unwieldy, quite apart from causing all the code to be include in a
1851        statically linked application, when only some functions are used. This is
1852        relevant even without the DFA addition now that patterns can be compiled in
1853        one application and matched in another.
1855        The downside of splitting up is that there have to be some external
1856        functions and data tables that are used internally in different modules of
1857        the library but which are not part of the API. These have all had their
1858        names changed to start with "_pcre_" so that they are unlikely to clash
1859        with other external names.
1861     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1862        a different (DFA) algorithm. Although it is slower than the original
1863        function, it does have some advantages for certain types of matching
1864        problem.
1866     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1867        including restarting after a partial match.
1869     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1870        defined when compiling for Windows was sent to me. I have put it into the
1871        code, though I have no means of testing or verifying it.
1873     7. Added the pcre_refcount() auxiliary function.
1875     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1876        match before or at the first newline in the subject string. In pcretest,
1877        the /f option on a pattern can be used to set this.
1879     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1880        would behave wrongly. This has been present in PCRE since release 4.0.
1882    10. A number of changes to the pcregrep command:
1884        (a) Refactored how -x works; insert ^(...)$ instead of setting
1885            PCRE_ANCHORED and checking the length, in preparation for adding
1886            something similar for -w.
1888        (b) Added the -w (match as a word) option.
1890        (c) Refactored the way lines are read and buffered so as to have more
1891            than one at a time available.
1893        (d) Implemented a pcregrep test script.
1895        (e) Added the -M (multiline match) option. This allows patterns to match
1896            over several lines of the subject. The buffering ensures that at least
1897            8K, or the rest of the document (whichever is the shorter) is available
1898            for matching (and similarly the previous 8K for lookbehind assertions).
1900        (f) Changed the --help output so that it now says
1902              -w, --word-regex(p)
1904            instead of two lines, one with "regex" and the other with "regexp"
1905            because that confused at least one person since the short forms are the
1906            same. (This required a bit of code, as the output is generated
1907            automatically from a table. It wasn't just a text change.)
1909        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1910            option but starts with a hyphen. Could be a pattern or a path name
1911            starting with a hyphen, for instance.
1913        (h) "-" can be given as a file name to represent stdin.
1915        (i) When file names are being printed, "(standard input)" is used for
1916            the standard input, for compatibility with GNU grep. Previously
1917            "<stdin>" was used.
1919        (j) The option --label=xxx can be used to supply a name to be used for
1920            stdin when file names are being printed. There is no short form.
1922        (k) Re-factored the options decoding logic because we are going to add
1923            two more options that take data. Such options can now be given in four
1924            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1926        (l) Added the -A, -B, and -C options for requesting that lines of context
1927            around matches be printed.
1929        (m) Added the -L option to print the names of files that do not contain
1930            any matching lines, that is, the complement of -l.
1932        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1933            continue to scan other files.
1935        (o) The -s option was incorrectly implemented. For compatibility with other
1936            greps, it now suppresses the error message for a non-existent or non-
1937            accessible file (but not the return code). There is a new option called
1938            -q that suppresses the output of matching lines, which was what -s was
1939            previously doing.
1941        (p) Added --include and --exclude options to specify files for inclusion
1942            and exclusion when recursing.
1944    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1945        Hopefully, it now does.
1947    12. Missing cast in pcre_study().
1949    13. Added an "uninstall" target to the makefile.
1951    14. Replaced "extern" in the function prototypes in Makefile.in with
1952        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1953        world, but is set differently for Windows.
1955    15. Added a second compiling function called pcre_compile2(). The only
1956        difference is that it has an extra argument, which is a pointer to an
1957        integer error code. When there is a compile-time failure, this is set
1958        non-zero, in addition to the error test pointer being set to point to an
1959        error message. The new argument may be NULL if no error number is required
1960        (but then you may as well call pcre_compile(), which is now just a
1961        wrapper). This facility is provided because some applications need a
1962        numeric error indication, but it has also enabled me to tidy up the way
1963        compile-time errors are handled in the POSIX wrapper.
1965    16. Added VPATH=.libs to the makefile; this should help when building with one
1966        prefix path and installing with another. (Or so I'm told by someone who
1967        knows more about this stuff than I do.)
1969    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1970        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1971        match everything, including newlines. This is not POSIX-compatible, but
1972        somebody wanted the feature. From pcretest it can be activated by using
1973        both the P and the s flags.
1975    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1977    19. libpcre.pc was being incorrectly installed as executable.
1979    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1980        it now also looks for '\r' so that it will work unmodified on Windows.
1982    21. Added Google's contributed C++ wrapper to the distribution.
1984    22. Added some untidy missing memory free() calls in pcretest, to keep
1985        Electric Fence happy when testing.
1989    Version 5.0 13-Sep-04
1990    ---------------------
1992     1. Internal change: literal characters are no longer packed up into items
1993        containing multiple characters in a single byte-string. Each character
1994        is now matched using a separate opcode. However, there may be more than one
1995        byte in the character in UTF-8 mode.
1997     2. The pcre_callout_block structure has two new fields: pattern_position and
1998        next_item_length. These contain the offset in the pattern to the next match
1999        item, and its length, respectively.
2001     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2002        insertion of callouts before each pattern item. Added the /C option to
2003        pcretest to make use of this.
2005     4. On the advice of a Windows user, the lines
2007          #if defined(_WIN32) || defined(WIN32)
2008          _setmode( _fileno( stdout ), 0x8000 );
2009          #endif  /* defined(_WIN32) || defined(WIN32) */
2011        have been added to the source of pcretest. This apparently does useful
2012        magic in relation to line terminators.
2014     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2015        for the benefit of those environments where the "b" makes a difference.
2017     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2018        to know about it. I have put a hack into configure.in that adds in code
2019        to set GCC=yes if CC=icc. This seems to end up at a point in the
2020        generated configure script that is early enough to affect the setting of
2021        compiler options, which is what is needed, but I have no means of testing
2022        whether it really works. (The user who reported this had patched the
2023        generated configure script, which of course I cannot do.)
2025        LATER: After change 22 below (new libtool files), the configure script
2026        seems to know about icc (and also ecc). Therefore, I have commented out
2027        this hack in configure.in.
2029     7. Added support for pkg-config (2 patches were sent in).
2031     8. Negated POSIX character classes that used a combination of internal tables
2032        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2033        [[:^ascii]]. Typically, they would match almost any characters. The other
2034        POSIX classes were not broken in this way.
2036     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2037        to find the match, as PCRE was deluded into thinking that the match had to
2038        start at the start point or following a newline. The same bug applied to
2039        patterns with negative forward assertions or any backward assertions
2040        preceding ".*" at the start, unless the pattern required a fixed first
2041        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2043  Version 2.09 14-Sep-99  10. In UTF-8 mode, when moving forwards in the subject after a failed match
2044  ----------------------      starting at the last subject character, bytes beyond the end of the subject
2045        string were read.
2047    11. Renamed the variable "class" as "classbits" to make life easier for C++
2048        users. (Previously there was a macro definition, but it apparently wasn't
2049        enough.)
2051    12. Added the new field "tables" to the extra data so that tables can be passed
2052        in at exec time, or the internal tables can be re-selected. This allows
2053        a compiled regex to be saved and re-used at a later time by a different
2054        program that might have everything at different addresses.
2056    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2057        -R library as well as a -L library.
2059    14. The debugging options of pcretest (-d on the command line or D on a
2060        pattern) showed incorrect output for anything following an extended class
2061        that contained multibyte characters and which was followed by a quantifier.
2063    15. Added optional support for general category Unicode character properties
2064        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2065        support. It adds about 90K to the size of the library. The meanings of the
2066        inbuilt class escapes such as \d and \s have NOT been changed.
2068    16. Updated pcredemo.c to include calls to free() to release the memory for the
2069        compiled pattern.
2071    17. The generated file chartables.c was being created in the source directory
2072        instead of in the building directory. This caused the build to fail if the
2073        source directory was different from the building directory, and was
2074        read-only.
2076    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2077        file. No doubt somebody will tell me if they don't make sense... Also added
2078        Dan Mooney's comments about building on OpenVMS.
2080    19. Added support for partial matching via the PCRE_PARTIAL option for
2081        pcre_exec() and the \P data escape in pcretest.
2083    20. Extended pcretest with 3 new pattern features:
2085        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2086              write the compiled pattern to the file whose name is "rest-of-line".
2087              This is a straight binary dump of the data, with the saved pointer to
2088              the character tables forced to be NULL. The study data, if any, is
2089              written too. After writing, pcretest reads a new pattern.
2091        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2092              compiled pattern from the given file. There must not be any
2093              occurrences of "<" in the file name (pretty unlikely); if there are,
2094              pcretest will instead treat the initial "<" as a pattern delimiter.
2095              After reading in the pattern, pcretest goes on to read data lines as
2096              usual.
2098        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2099              and 16-bit fields in a compiled pattern, to simulate a pattern that
2100              was compiled on a host of opposite endianness.
2102    21. The pcre-exec() function can now cope with patterns that were compiled on
2103        hosts of opposite endianness, with this restriction:
2105          As for any compiled expression that is saved and used later, the tables
2106          pointer field cannot be preserved; the extra_data field in the arguments
2107          to pcre_exec() should be used to pass in a tables address if a value
2108          other than the default internal tables were used at compile time.
2110    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2111        now diagnosed as an error. Previously, most of the time, a negative number
2112        would have been treated as zero, but if in addition "ovector" was passed as
2113        NULL, a crash could occur.
2115    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2116        new versions from the libtool 1.5 distribution (the last one is a copy of
2117        a file called libtool.m4). This seems to have fixed the need to patch
2118        "configure" to support Darwin 1.3 (which I used to do). However, I still
2119        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2120        workstation).
2122    24. Changed the PCRE licence to be the more standard "BSD" licence.
2125    Version 4.5 01-Dec-03
2126    ---------------------
2128     1. There has been some re-arrangement of the code for the match() function so
2129        that it can be compiled in a version that does not call itself recursively.
2130        Instead, it keeps those local variables that need separate instances for
2131        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2132        needs to "recurse". Keeping track of where control must go is done by means
2133        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2134        hide most of the details from the main code, and operates only if
2135        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2136        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2137        operating.
2139        To make it easier for callers to provide specially tailored get/free
2140        functions for this usage, two new functions, pcre_stack_malloc, and
2141        pcre_stack_free, are used. They are always called in strict stacking order,
2142        and the size of block requested is always the same.
2144        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2145        PCRE has been compiled to use the stack or the heap for recursion. The
2146        -C option of pcretest uses this to show which version is compiled.
2148        A new data escape \S, is added to pcretest; it causes the amounts of store
2149        obtained and freed by both kinds of malloc/free at match time to be added
2150        to the output.
2152     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2153        what's available on my current Linux desktop machine.
2155     3. When matching a UTF-8 string, the test for a valid string at the start has
2156        been extended. If start_offset is not zero, PCRE now checks that it points
2157        to a byte that is the start of a UTF-8 character. If not, it returns
2158        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2159        this is necessary because there may be backward assertions in the pattern.
2160        When matching the same subject several times, it may save resources to use
2161        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2163     4. The code for checking the validity of UTF-8 strings has been tightened so
2164        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2165        containing "overlong sequences".
2167     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2168        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2169        should have been "&", but it just so happened that all the cases this let
2170        through by mistake were picked up later in the function.
2172     6. I had used a variable called "isblank" - this is a C99 function, causing
2173        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2175     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2176        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2177        so the version is shown; (c) stop "make test" echoing "./RunTest".
2179     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2181     9. The prototype for memmove() for systems that don't have it was using
2182        size_t, but the inclusion of the header that defines size_t was later. I've
2183        moved the #includes for the C headers earlier to avoid this.
2185    10. Added some adjustments to the code to make it easier to compiler on certain
2186        special systems:
2188          (a) Some "const" qualifiers were missing.
2189          (b) Added the macro EXPORT before all exported functions; by default this
2190              is defined to be empty.
2191          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2192              that it reads its output file name as an argument instead of writing
2193              to the standard output and assuming this can be redirected.
2195    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2196        class containing characters with values greater than 255, PCRE compilation
2197        went into a loop.
2199    12. A recursive reference to a subpattern that was within another subpattern
2200        that had a minimum quantifier of zero caused PCRE to crash. For example,
2201        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2202        recursion. If the recursively-called subpattern itself had a zero repeat,
2203        that was OK.
2205    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2206        buffer into which it was copied (for escape processing) was still set at
2207        1024, so long lines caused crashes.
2209    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2210        "internal error: code overflow...". This applied to any character class
2211        that was followed by a possessive quantifier.
2213    15. Modified the Makefile to add libpcre.la as a prerequisite for
2214        libpcreposix.la because I was told this is needed for a parallel build to
2215        work.
2217    16. If a pattern that contained .* following optional items at the start was
2218        studied, the wrong optimizing data was generated, leading to matching
2219        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2220        matching string must start with a or b or c. The correct conclusion for
2221        this pattern is that a match can start with any character.
2224    Version 4.4 13-Aug-03
2225    ---------------------
2227     1. In UTF-8 mode, a character class containing characters with values between
2228        127 and 255 was not handled correctly if the compiled pattern was studied.
2229        In fixing this, I have also improved the studying algorithm for such
2230        classes (slightly).
2232     2. Three internal functions had redundant arguments passed to them. Removal
2233        might give a very teeny performance improvement.
2235     3. Documentation bug: the value of the capture_top field in a callout is *one
2236        more than* the number of the hightest numbered captured substring.
2238     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2239        in incorrectly linking with a previously installed version. They now link
2240        explicitly with libpcre.la.
2242     5. configure.in no longer needs to recognize Cygwin specially.
2244     6. A problem in pcre.in for Windows platforms is fixed.
2246     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2247        pcretest, it used to include the size of the study block as part of its
2248        output. Unfortunately, the structure contains a field that has a different
2249        size on different hardware architectures. This meant that the tests that
2250        showed this size failed. As the block is currently always of a fixed size,
2251        this information isn't actually particularly useful in pcretest output, so
2252        I have just removed it.
2254     8. Three pre-processor statements accidentally did not start in column 1.
2255        Sadly, there are *still* compilers around that complain, even though
2256        standard C has not required this for well over a decade. Sigh.
2258     9. In pcretest, the code for checking callouts passed small integers in the
2259        callout_data field, which is a void * field. However, some picky compilers
2260        complained about the casts involved for this on 64-bit systems. Now
2261        pcretest passes the address of the small integer instead, which should get
2262        rid of the warnings.
2264    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2265        both compile and run time, and gives an error if an invalid UTF-8 sequence
2266        is found. There is a option for disabling this check in cases where the
2267        string is known to be correct and/or the maximum performance is wanted.
2269    11. In response to a bug report, I changed one line in Makefile.in from
2271            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2272        to
2273            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2275        to look similar to other lines, but I have no way of telling whether this
2276        is the right thing to do, as I do not use Windows. No doubt I'll get told
2277        if it's wrong...
2280    Version 4.3 21-May-03
2281    ---------------------
2283    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2284       Makefile.
2286    2. Some refactoring to improve the quality of the code:
2288       (i)   The utf8_table... variables are now declared "const".
2290       (ii)  The code for \cx, which used the "case flipping" table to upper case
2291             lower case letters, now just substracts 32. This is ASCII-specific,
2292             but the whole concept of \cx is ASCII-specific, so it seems
2293             reasonable.
2295       (iii) PCRE was using its character types table to recognize decimal and
2296             hexadecimal digits in the pattern. This is silly, because it handles
2297             only 0-9, a-f, and A-F, but the character types table is locale-
2298             specific, which means strange things might happen. A private
2299             table is now used for this - though it costs 256 bytes, a table is
2300             much faster than multiple explicit tests. Of course, the standard
2301             character types table is still used for matching digits in subject
2302             strings against \d.
2304       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2305             ending in _t are). So I've renamed it as ESC_tee.
2307    3. The first argument for regexec() in the POSIX wrapper should have been
2308       defined as "const".
2310    4. Changed pcretest to use malloc() for its buffers so that they can be
2311       Electric Fenced for debugging.
2313    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2314       to read one or more bytes before the start of the subject string. Often this
2315       had no effect on PCRE's behaviour, but in some circumstances it could
2316       provoke a segmentation fault.
2318    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2319       to try to read one or more bytes before the start of the subject string.
2321    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2322       UTF-8 support could misbehave in various ways if the subject string
2323       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2324       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2325       back over UTF-8 characters.)
2328    Version 4.2 14-Apr-03
2329    ---------------------
2331    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2333    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2334         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2335         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2336         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2337         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2338           and BUILD_EXEEXT
2339         Note: automatic setting of the BUILD variables is not yet working
2340         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2341           compile-time but not at link-time
2342         [LINK]: use for linking executables only
2343         make different versions for Windows and non-Windows
2344         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2345           libraries
2346         [LINK_FOR_BUILD]: new variable
2347         [OBJEXT]: use throughout
2348         [EXEEXT]: use throughout
2349         <winshared>: new target
2350         <wininstall>: new target
2351         <dftables.o>: use native compiler
2352         <dftables>: use native linker
2353         <install>: handle Windows platform correctly
2354         <clean>: ditto
2355         <check>: ditto
2356         copy DLL to top builddir before testing
2358       As part of these changes, -no-undefined was removed again. This was reported
2359       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2360       in any case.
2362    3. Some tidies to get rid of compiler warnings:
2364       . In the match_data structure, match_limit was an unsigned long int, whereas
2365         match_call_count was an int. I've made them both unsigned long ints.
2367       . In pcretest the fact that a const uschar * doesn't automatically cast to
2368         a void * provoked a warning.
2370       . Turning on some more compiler warnings threw up some "shadow" variables
2371         and a few more missing casts.
2373    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2374       option, a class that contained a single character with a value between 128
2375       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2377    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2378       option, a class that contained several characters, but with at least one
2379       whose value was between 128 and 255 caused PCRE to crash.
2382    Version 4.1 12-Mar-03
2383    ---------------------
2385    1. Compiling with gcc -pedantic found a couple of places where casts were
2386    needed, and a string in dftables.c that was longer than standard compilers are
2387    required to support.
2389    2. Compiling with Sun's compiler found a few more places where the code could
2390    be tidied up in order to avoid warnings.
2392    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2393    first of these names is deprecated in the latest Autoconf in favour of the name
2394    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2395    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2396    analogy I have changed it to CFLAGS_FOR_BUILD.
2398    4. Added -no-undefined to the linking command in the Makefile, because this is
2399    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2400    linking step for the pcreposix library.
2402    5. PCRE was failing to diagnose the case of two named groups with the same
2403    name.
2405    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2406    literal character that is needed in the subject for a match, and scans along to
2407    ensure that it is present before embarking on the full matching process. This
2408    saves time in cases of nested unlimited repeats that are never going to match.
2409    Problem: the scan can take a lot of time if the subject is very long (e.g.
2410    megabytes), thus penalizing straightforward matches. It is now done only if the
2411    amount of subject to be scanned is less than 1000 bytes.
2413    7. A lesser problem with the same optimization is that it was recording the
2414    first character of an anchored pattern as "needed", thus provoking a search
2415    right along the subject, even when the first match of the pattern was going to
2416    fail. The "needed" character is now not set for anchored patterns, unless it
2417    follows something in the pattern that is of non-fixed length. Thus, it still
2418    fulfils its original purpose of finding quick non-matches in cases of nested
2419    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2422    Version 4.0 17-Feb-03
2423    ---------------------
2425    1. If a comment in an extended regex that started immediately after a meta-item
2426    extended to the end of string, PCRE compiled incorrect data. This could lead to
2427    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2429    2. Moved to autoconf 2.53 and libtool 1.4.2.
2431    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2432    the special perltest8 script is no longer needed - all the tests can be run
2433    from a single perltest script.
2435    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2436    by \s. It has now been removed in PCRE. This means it isn't recognized as
2437    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2438    class [:space:] *does* include VT, thereby creating a mess.
2440    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2441    space and tab.
2443    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2444    its new features into the main test script, reducing the number of scripts.
2446    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2447    were backward compatible, and made the (?i) apply to the whole pattern, as if
2448    /i were given. Now it behaves more logically, and applies the option setting
2449    only to what follows. PCRE has been changed to follow suit. However, if it
2450    finds options settings right at the start of the pattern, it extracts them into
2451    the global options, as before. Thus, they show up in the info data.
2453    8. Added support for the \Q...\E escape sequence. Characters in between are
2454    treated as literals. This is slightly different from Perl in that $ and @ are
2455    also handled as literals inside the quotes. In Perl, they will cause variable
2456    interpolation. Note the following examples:
2458        Pattern            PCRE matches      Perl matches
2460        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2461        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2462        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2464    For compatibility with Perl, \Q...\E sequences are recognized inside character
2465    classes as well as outside them.
2467    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2468    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2469    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2470    signed/unsigned warnings.
2472    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2473    option for pcretest, so I've replaced it by a simple function that does just
2474    that job.
2476    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2477    "pcregrep -".
2479    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2480    Java package. This provides some syntactic sugar for simple cases of what my
2481    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2482    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2483    item, you can use this simplified notation. Note that only makes sense with
2484    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2485    greediness, whatever the setting of the PCRE_UNGREEDY option.
2487    13. A change of greediness default within a pattern was not taking effect at
2488    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2489    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2490    was abstracted outside.
2492    14. PCRE now supports the \G assertion. It is true when the current matching
2493    position is at the start point of the match. This differs from \A when the
2494    starting offset is non-zero. Used with the /g option of pcretest (or similar
2495    code), it works in the same way as it does for Perl's /g option. If all
2496    alternatives of a regex begin with \G, the expression is anchored to the start
2497    match position, and the "anchored" flag is set in the compiled expression.
2499    15. Some bugs concerning the handling of certain option changes within patterns
2500    have been fixed. These applied to options other than (?ims). For example,
2501    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2502    been the other way round. Some of this was related to change 7 above.
2504    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2505    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2506    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2507    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2509    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2510    mode. Unlike ".", it always matches newline, whatever the setting of
2511    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2512    assertions. Perl allows it, but it doesn't (in general) work because it can't
2513    calculate the length of the lookbehind. At least, that's the case for Perl
2514    5.8.0 - I've been told they are going to document that it doesn't work in
2515    future.
2517    18. Added an error diagnosis for escapes that PCRE does not support: these are
2518    \L, \l, \N, \P, \p, \U, \u, and \X.
2520    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2521    reading past the end of the pattern in cases such as /[abcd/.
2523    20. PCRE was getting more memory than necessary for patterns with classes that
2524    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2526    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2527    compiling PCRE for use with Virtual Pascal.
2529    22. Small fix to the Makefile to make it work properly if the build is done
2530    outside the source tree.
2532    23. Added a new extension: a condition to go with recursion. If a conditional
2533    subpattern starts with (?(R) the "true" branch is used if recursion has
2534    happened, whereas the "false" branch is used only at the top level.
2536    24. When there was a very long string of literal characters (over 255 bytes
2537    without UTF support, over 250 bytes with UTF support), the computation of how
2538    much memory was required could be incorrect, leading to segfaults or other
2539    strange effects.
2541    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2542    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2543    there was a subsequent back reference to those brackets. This meant that, for
2544    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2545    possible to check for precisely this case. All we can do is abandon the
2546    optimization if .* occurs inside capturing brackets when there are any back
2547    references whatsoever. (See below for a better fix that came later.)
2549    26. The handling of the optimization for finding the first character of a
2550    non-anchored pattern, and for finding a character that is required later in the
2551    match were failing in some cases. This didn't break the matching; it just
2552    failed to optimize when it could. The way this is done has been re-implemented.
2554    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2556    28. Added a new feature that provides some of the functionality that Perl
2557    provides with (?{...}). The facility is termed a "callout". The way it is done
2558    in PCRE is for the caller to provide an optional function, by setting
2559    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2560    global variable. By default it is unset, which disables all calling out. To get
2561    the function called, the regex must include (?C) at appropriate points. This
2562    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2563    This provides a means of identifying different callout points. When PCRE
2564    reaches such a point in the regex, if pcre_callout has been set, the external
2565    function is called. It is provided with data in a structure called
2566    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2567    matching continues; if it returns a non-zero value, the match at the current
2568    point fails. However, backtracking will occur if possible. [This was changed
2569    later and other features added - see item 49 below.]
2571    29. pcretest is upgraded to test the callout functionality. It provides a
2572    callout function that displays information. By default, it shows the start of
2573    the match and the current position in the text. There are some new data escapes
2574    to vary what happens:
2576        \C+         in addition, show current contents of captured substrings
2577        \C-         do not supply a callout function
2578        \C!n        return 1 when callout number n is reached
2579        \C!n!m      return 1 when callout number n is reached for the mth time
2581    30. If pcregrep was called with the -l option and just a single file name, it
2582    output "<stdin>" if a match was found, instead of the file name.
2584    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2585    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2586    pcre_exec(). This saves a malloc/free per call. The default value of
2587    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2588    when configuring.
2590    32. The default maximum size of a compiled pattern is 64K. There have been a
2591    few cases of people hitting this limit. The code now uses macros to handle the
2592    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2593    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2594    configuring. Tests 2 and 5 work only with 2-byte links because they output
2595    debugging information about compiled patterns.
2597    33. Internal code re-arrangements:
2599    (a) Moved the debugging function for printing out a compiled regex into
2600        its own source file (printint.c) and used #include to pull it into
2601        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2602        separate copies.
2604    (b) Defined the list of op-code names for debugging as a macro in
2605        internal.h so that it is next to the definition of the opcodes.
2607    (c) Defined a table of op-code lengths for simpler skipping along compiled
2608        code. This is again a macro in internal.h so that it is next to the
2609        definition of the opcodes.
2611    34. Added support for recursive calls to individual subpatterns, along the
2612    lines of Robin Houston's patch (but implemented somewhat differently).
2614    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2615    allow it to read and process whole directories in Win32. This code was
2616    contributed by Lionel Fourquaux; it has not been tested by me.
2618    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2619    used to name a group. Names consist of alphanumerics and underscores, and must
2620    be unique. Back references use the syntax (?P=name) and recursive calls use
2621    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2622    numbers. The function pcre_fullinfo() can be used after compilation to extract
2623    a name/number map. There are three relevant calls:
2625      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2626      PCRE_INFO_NAMECOUNT            yields the number of entries
2627      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2629    The map is a vector of fixed-size entries. The size of each entry depends on
2630    the length of the longest name used. The first two bytes of each entry are the
2631    group number, most significant byte first. There follows the corresponding
2632    name, zero terminated. The names are in alphabetical order.
2634    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2635    case instead of 255. Making it the same both with and without UTF-8 support
2636    means that the same test output works with both.
2638    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2639    calling malloc() with a zero argument.
2641    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2642    optimization. I've improved things by keeping a bitmap of backreferences with
2643    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2644    fact referenced, the optimization can be applied. It is unlikely that a
2645    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2646    the match to follow \n) will appear inside brackets with a number greater than
2647    31, but if it does, any back reference > 31 suppresses the optimization.
2649    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2650    of disabling numbered capturing parentheses. Any opening parenthesis that is
2651    not followed by ? behaves as if it were followed by ?: but named parentheses
2652    can still be used for capturing (and they will acquire numbers in the usual
2653    way).
2655    41. Redesigned the return codes from the match() function into yes/no/error so
2656    that errors can be passed back from deep inside the nested calls. A malloc
2657    failure while inside a recursive subpattern call now causes the
2658    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2660    42. It is now possible to set a limit on the number of times the match()
2661    function is called in a call to pcre_exec(). This facility makes it possible to
2662    limit the amount of recursion and backtracking, though not in a directly
2663    obvious way, because the match() function is used in a number of different
2664    circumstances. The count starts from zero for each position in the subject
2665    string (for non-anchored patterns). The default limit is, for compatibility, a
2666    large number, namely 10 000 000. You can change this in two ways:
2668    (a) When configuring PCRE before making, you can use --with-match-limit=n
2669        to set a default value for the compiled library.
2671    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2672        a different value is set. See 45 below.
2674    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2676    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2677    of things that can be changed at compile time. The first argument specifies
2678    what is wanted and the second points to where the information is to be placed.
2679    The current list of available information is:
2681      PCRE_CONFIG_UTF8
2683    The output is an integer that is set to one if UTF-8 support is available;
2684    otherwise it is set to zero.
2688    The output is an integer that it set to the value of the code that is used for
2689    newline. It is either LF (10) or CR (13).
2693    The output is an integer that contains the number of bytes used for internal
2694    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2698    The output is an integer that contains the threshold above which the POSIX
2699    interface uses malloc() for output vectors. See item 31 above.
2703    The output is an unsigned integer that contains the default limit of the number
2704    of match() calls in a pcre_exec() execution. See 42 above.
2706    44. pcretest has been upgraded by the addition of the -C option. This causes it
2707    to extract all the available output from the new pcre_config() function, and to
2708    output it. The program then exits immediately.
2710    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2711    order to support additional features. One way would have been to define
2712    pcre_exec2() (for example) with extra arguments, but this would not have been
2713    extensible, and would also have required all calls to the original function to
2714    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2715    is used for passing in "extra" data from pcre_study().
2717    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2718    contains the following fields:
2720      flags         a bitmap indicating which of the following fields are set
2721      study_data    opaque data from pcre_study()
2722      match_limit   a way of specifying a limit on match() calls for a specific
2723                      call to pcre_exec()
2724      callout_data  data for callouts (see 49 below)
2726    The flag bits are also defined in pcre.h, and are
2732    The pcre_study() function now returns one of these new pcre_extra blocks, with
2733    the actual study data pointed to by the study_data field, and the
2734    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2735    before. That is, this change is entirely upwards-compatible and requires no
2736    change to existing code.
2738    If you want to pass in additional data to pcre_exec(), you can either place it
2739    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2740    block.
2742    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2743    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2744    times with different match limits, until it finds the minimum value needed for
2745    pcre_exec() to complete. The value is then output. This can be instructive; for
2746    most simple matches the number is quite small, but for pathological cases it
2747    gets very large very quickly.
2749    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2750    returns the size of the data block pointed to by the study_data field in a
2751    pcre_extra block, that is, the value that was passed as the argument to
2752    pcre_malloc() when PCRE was getting memory in which to place the information
2753    created by pcre_study(). The fourth argument should point to a size_t variable.
2754    pcretest has been extended so that this information is shown after a successful
2755    pcre_study() call when information about the compiled regex is being displayed.
2757    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2758    because what follows is always an absolute path. (Later: it turns out that this
2759    is more than cosmetic for MinGW, because it doesn't like empty path
2760    components.)
2762    49. Some changes have been made to the callout feature (see 28 above):
2764    (i)  A callout function now has three choices for what it returns:
2766           0  =>  success, carry on matching
2767         > 0  =>  failure at this point, but backtrack if possible
2768         < 0  =>  serious error, return this value from pcre_exec()
2770         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2771         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2772         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2773         use by callout functions. It will never be used by PCRE itself.
2775    (ii) The pcre_extra structure (see 45 above) has a void * field called
2776         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2777         pcre_callout_block structure has a field of the same name. The contents of
2778         the field passed in the pcre_extra structure are passed to the callout
2779         function in the corresponding field in the callout block. This makes it
2780         easier to use the same callout-containing regex from multiple threads. For
2781         testing, the pcretest program has a new data escape
2783           \C*n        pass the number n (may be negative) as callout_data
2785         If the callout function in pcretest receives a non-zero value as
2786         callout_data, it returns that value.
2788    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2789    there were some redundant $(CFLAGS) in commands that are now specified as
2790    $(LINK), which already includes $(CFLAGS).
2792    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2793    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2794    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2795    one-byte characters throughout. Note that case-insensitive matching applies
2796    only to characters whose values are less than 256. PCRE doesn't support the
2797    notion of cases for higher-valued characters.
2799    (i)   A character class whose characters are all within 0-255 is handled as
2800          a bit map, and the map is inverted for negative classes. Previously, a
2801          character > 255 always failed to match such a class; however it should
2802          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2804    (ii)  A negated character class with a single character < 255 is coded as
2805          "not this character" (OP_NOT). This wasn't working properly when the test
2806          character was multibyte, either singly or repeated.
2808    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2809          mode, for example: \x{100}{2,3}.
2811    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2812          singly or repeated) now correctly test multibyte characters. However,
2813          PCRE doesn't recognize any characters with values greater than 255 as
2814          digits, spaces, or word characters. Such characters always match \D, \S,
2815          and \W, and never match \d, \s, or \w.
2817    (v)   Classes may now contain characters and character ranges with values
2818          greater than 255. For example: [ab\x{100}-\x{400}].
2820    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2821          PCRE in UTF-8 mode.
2823    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2824    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2825    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2826    value.)
2828    53. The single man page has become too large. I have therefore split it up into
2829    a number of separate man pages. These also give rise to individual HTML pages;
2830    these are now put in a separate directory, and there is an index.html page that
2831    lists them all. Some hyperlinking between the pages has been installed.
2833    54. Added convenience functions for handling named capturing parentheses.
2835    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2836    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2837    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2838    are faulted.
2840    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2841    calling configure. These values are used when compiling the dftables.c program
2842    which is run to generate the source of the default character tables. They
2843    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2844    you will need to set these values.
2846    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2849    Version 3.9 02-Jan-02
2850    ---------------------
2852    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2854    2. If --disable-static was given, the building process failed when trying to
2855    build pcretest and pcregrep. (For some reason it was using libtool to compile
2856    them, which is not right, as they aren't part of the library.)
2859    Version 3.8 18-Dec-01
2860    ---------------------
2862    1. The experimental UTF-8 code was completely screwed up. It was packing the
2863    bytes in the wrong order. How dumb can you get?
2866    Version 3.7 29-Oct-01
2867    ---------------------
2869    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2870    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2871    this didn't happen under Solaris 8, where I normally test things.
2873    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2874    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2875    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2876    this fix an hour or so after the initial 3.7 release.)
2879    Version 3.6 23-Oct-01
2880    ---------------------
2882    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2883    offsets passed as NULL with zero offset count.
2885    2. The config.guess and config.sub files had not been updated when I moved to
2886    the latest autoconf.
2889    Version 3.5 15-Aug-01
2890    ---------------------
2892    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2893    had been forgotten.
2895    2. By using declared but undefined structures, we can avoid using "void"
2896    definitions in pcre.h while keeping the internal definitions of the structures
2897    private.
2899    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2900    user point of view, this means that both static and shared libraries are built
2901    by default, but this can be individually controlled. More of the work of
2902    handling this static/shared cases is now inside libtool instead of PCRE's make
2903    file.
2905    4. The pcretest utility is now installed along with pcregrep because it is
2906    useful for users (to test regexs) and by doing this, it automatically gets
2907    relinked by libtool. The documentation has been turned into a man page, so
2908    there are now .1, .txt, and .html versions in /doc.
2910    5. Upgrades to pcregrep:
2911       (i)   Added long-form option names like gnu grep.
2912       (ii)  Added --help to list all options with an explanatory phrase.
2913       (iii) Added -r, --recursive to recurse into sub-directories.
2914       (iv)  Added -f, --file to read patterns from a file.
2916    6. pcre_exec() was referring to its "code" argument before testing that
2917    argument for NULL (and giving an error if it was NULL).
2919    7. Upgraded Makefile.in to allow for compiling in a different directory from
2920    the source directory.
2922    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2923    options bits, the pointer it was passed was to an int instead of to an unsigned
2924    long int. This mattered only on 64-bit systems.
2926    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2927    generated) instead of pcre.in, which it its source. Also made the same change
2928    in several of the .c files.
2930    10. A new release of gcc defines printf() as a macro, which broke pcretest
2931    because it had an ifdef in the middle of a string argument for printf(). Fixed
2932    by using separate calls to printf().
2934    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2935    script, to force use of CR or LF instead of \n in the source. On non-Unix
2936    systems, the value can be set in config.h.
2938    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2939    absolute limit. Changed the text of the error message to make this clear, and
2940    likewise updated the man page.
2942    13. The limit of 99 on the number of capturing subpatterns has been removed.
2943    The new limit is 65535, which I hope will not be a "real" limit.
2946    Version 3.4 22-Aug-00
2947    ---------------------
2949    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2951    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2954    Version 3.3 01-Aug-00
2955    ---------------------
2957    1. If an octal character was given, but the value was greater than \377, it
2958    was not getting masked to the least significant bits, as documented. This could
2959    lead to crashes in some systems.
2961    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2962    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2964    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2965    These just pass their arguments on to (pcre_free)(), but they are provided
2966    because some uses of PCRE bind it to non-C systems that can call its functions,
2967    but cannot call free() or pcre_free() directly.
2969    4. Add "make test" as a synonym for "make check". Corrected some comments in
2970    the Makefile.
2972    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2973    Makefile.
2975    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2976    command called pgrep for grepping around the active processes.
2978    7. Added the beginnings of support for UTF-8 character strings.
2980    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2981    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2982    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2983    out for the ar command.)
2986    Version 3.2 12-May-00
2987    ---------------------
2989    This is purely a bug fixing release.
2991    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2992    of ZA. This was just one example of several cases that could provoke this bug,
2993    which was introduced by change 9 of version 2.00. The code for breaking
2994    infinite loops after an iteration that matches an empty string was't working
2995    correctly.
2997    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2998    when matched against abbab (for example). After matching an empty string, it
2999    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3000    caused it to match further down the string than it should.
3002    3. The code contained an inclusion of sys/types.h. It isn't clear why this
3003    was there because it doesn't seem to be needed, and it causes trouble on some
3004    systems, as it is not a Standard C header. It has been removed.
3006    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3007    were reported on the Macintosh. The changes were from
3009      while ((c = *(++ptr)) != 0 && c != '\n');
3010    to
3011      while ((c = *(++ptr)) != 0 && c != '\n') ;
3013    Totally extraordinary, but if that's what it takes...
3015    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3016    available. Added HAVE_BCOPY and an autoconf test for it; if neither
3017    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3018    assumes the way PCRE uses memmove() (always moving upwards).
3020    6. PCRE is being used in one environment where strchr() is not available. There
3021    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3022    faster code anyway.
3025    Version 3.1 09-Feb-00
3026    ---------------------
3028    The only change in this release is the fixing of some bugs in Makefile.in for
3029    the "install" target:
3031    (1) It was failing to install pcreposix.h.
3033    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3036    Version 3.0 01-Feb-00
3037    ---------------------
3039  1. Add support for the /+ modifier to perltest (to output $` like it does in  1. Add support for the /+ modifier to perltest (to output $` like it does in
3040  pcretest).  pcretest).
# Line 23  captured string vector to pcre_exec(), b Line 3054  captured string vector to pcre_exec(), b
3054  required a bigger vector, with some working space on the end. This means that  required a bigger vector, with some working space on the end. This means that
3055  the POSIX wrapper now has to get and free some memory, and copy the results.  the POSIX wrapper now has to get and free some memory, and copy the results.
3057    6. Added some simple autoconf support, placing the test data and the
3058    documentation in separate directories, re-organizing some of the
3059    information files, and making it build pcre-config (a GNU standard). Also added
3060    libtool support for building PCRE as a shared library, which is now the
3061    default.
3063    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3064    09 are not valid octal constants. Single digits will be used for minor values
3065    less than 10.
3067    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3068    existing programs that set these in the POSIX interface can use PCRE without
3069    modification.
3071    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3072    return all that pcre_info() returns, plus additional data. The pcre_info()
3073    function is retained for compatibility, but is considered to be obsolete.
3075    10. Added experimental recursion feature (?R) to handle one common case that
3076    Perl 5.6 will be able to do with (?p{...}).
3078    11. Added support for POSIX character classes like [:alpha:], which Perl is
3079    adopting.
3082  Version 2.08 31-Aug-99  Version 2.08 31-Aug-99
3083  ----------------------  ----------------------

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