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revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC revision 438 by ph10, Sun Sep 6 20:00:47 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8        was out-of-date, and there was no check on the pcre_compile() error code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 offset of the earliest inspected character
55        for the match and the offset of the end of the subject are set in them when
56        PCRE_ERROR_PARTIAL is returned.
58    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
59        synonymous with PCRE_PARTIAL, for backwards compatibility, and
60        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
61        and may be more useful for multi-segment matching, especially with
62        pcre_exec().
64    11. Partial matching with pcre_exec() is now more intuitive. A partial match
65        used to be given if ever the end of the subject was reached; now it is
66        given only if matching could not proceed because another character was
67        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
68        string "Z", which now yields "no match" instead of "partial match". In the
69        case of pcre_dfa_exec(), "no match" is given if every matching path for the
70        final character ended with (*FAIL).
72    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
73        if the pattern had a "must contain" character that was already found in the
74        earlier partial match, unless partial matching was again requested. For
75        example, with the pattern /dog.(body)?/, the "must contain" character is
76        "g". If the first part-match was for the string "dog", restarting with
77        "sbody" failed. This bug has been fixed.
79    13. The string returned by pcre_dfa_exec() after a partial match has been
80        changed so that it starts at the first inspected character rather than the
81        first character of the match. This makes a difference only if the pattern
82        starts with a lookbehind assertion or \b or \B (\K is not supported by
83        pcre_dfa_exec()). It's an incompatible change, but it makes the two
84        matching functions compatible, and I think it's the right thing to do.
86    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
87        so that the demonstration program is easily available in environments where
88        PCRE has not been installed from source.
90    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
91        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
92        library.
94    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
95        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
96        is not the first non-POSIX option to be added. Clearly some people find
97        these options useful.
99    17. If a caller to the POSIX matching function regexec() passes a non-zero
100        value for nmatch with a NULL value for pmatch, the value of
101        nmatch is forced to zero.
103    18. RunGrepTest did not have a test for the availability of the -u option of
104        the diff command, as RunTest does. It now checks in the same way as
105        RunTest, and also checks for the -b option.
107    19. If an odd number of negated classes containing just a single character
108        interposed, within parentheses, between a forward reference to a named
109        subpattern and the definition of the subpattern, compilation crashed with
110        an internal error, complaining that it could not find the referenced
111        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
112        [The bug was that it was starting one character too far in when skipping
113        over the character class, thus treating the ] as data rather than
114        terminating the class. This meant it could skip too much.]
117    Version 7.9 11-Apr-09
118    ---------------------
120    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
121        (pcretest), all targets were linked against these libraries. This included
122        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
123        libraries. This caused unwanted dependencies to be created. This problem
124        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
125        pcretest is linked with readline.
127    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
128        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
129        moved outside it again, because FALSE and TRUE are already defined in AIX,
130        but BOOL is not.
132    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
133        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
135    4.  The pcregrep documentation said spaces were inserted as well as colons (or
136        hyphens) following file names and line numbers when outputting matching
137        lines. This is not true; no spaces are inserted. I have also clarified the
138        wording for the --colour (or --color) option.
140    5.  In pcregrep, when --colour was used with -o, the list of matching strings
141        was not coloured; this is different to GNU grep, so I have changed it to be
142        the same.
144    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
145        each matching line was coloured. Now it goes on to look for further matches
146        of any of the test patterns, which is the same behaviour as GNU grep.
148    7.  A pattern that could match an empty string could cause pcregrep to loop; it
149        doesn't make sense to accept an empty string match in pcregrep, so I have
150        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
151        seems to be how GNU grep behaves.
153    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
154        start or after a newline", because the conditional assertion was not being
155        correctly handled. The rule now is that both the assertion and what follows
156        in the first alternative must satisfy the test.
158    9.  If auto-callout was enabled in a pattern with a conditional group whose
159        condition was an assertion, PCRE could crash during matching, both with
160        pcre_exec() and pcre_dfa_exec().
162    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
163        used for matching.
165    11. Unicode property support in character classes was not working for
166        characters (bytes) greater than 127 when not in UTF-8 mode.
168    12. Added the -M command line option to pcretest.
170    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
172    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
174    16. Added comments and documentation about mis-use of no_arg in the C++
175        wrapper.
177    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
178        from Martin Jerabek that uses macro names for all relevant character and
179        string constants.
181    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
182        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
183        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
184        these, but not everybody uses configure.
186    19. A conditional group that had only one branch was not being correctly
187        recognized as an item that could match an empty string. This meant that an
188        enclosing group might also not be so recognized, causing infinite looping
189        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
190        with the subject "ab", where knowledge that the repeated group can match
191        nothing is needed in order to break the loop.
193    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
194        exec(), but without supplying a callout function, matching went wrong.
196    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
197        leak if the size of the offset vector was greater than 30. When the vector
198        is smaller, the saved offsets during recursion go onto a local stack
199        vector, but for larger vectors malloc() is used. It was failing to free
200        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
201        error, in fact).
203    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
204        heapframe that is used only when UTF-8 support is enabled. This caused no
205        problem, but was untidy.
207    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
208        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
209        included within another project.
211    24. Steven Van Ingelgem's patches to add more options to the CMake support,
212        slightly modified by me:
214          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
215              not building pcregrep.
217          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
218              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
220    25. Forward references, both numeric and by name, in patterns that made use of
221        duplicate group numbers, could behave incorrectly or give incorrect errors,
222        because when scanning forward to find the reference group, PCRE was not
223        taking into account the duplicate group numbers. A pattern such as
224        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
226    26. Changed a few more instances of "const unsigned char *" to USPTR, making
227        the feature of a custom pointer more persuasive (as requested by a user).
229    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
230        pcretest.c, inside #ifndefs, because it seems they are sometimes already
231        pre-defined.
233    28. Added support for (*UTF8) at the start of a pattern.
235    29. Arrange for flags added by the "release type" setting in CMake to be shown
236        in the configuration summary.
239    Version 7.8 05-Sep-08
240    ---------------------
242    1.  Replaced UCP searching code with optimized version as implemented for Ad
243        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
244        stage table and inline lookup instead of a function, giving speed ups of 2
245        to 5 times on some simple patterns that I tested. Permission was given to
246        distribute the MultiStage2.py script that generates the tables (it's not in
247        the tarball, but is in the Subversion repository).
249    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
250        scripts.
252    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
253        a group with a zero qualifier. The result of the study could be incorrect,
254        or the function might crash, depending on the pattern.
256    4.  Caseless matching was not working for non-ASCII characters in back
257        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
258        It now works when Unicode Property Support is available.
260    5.  In pcretest, an escape such as \x{de} in the data was always generating
261        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
262        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
263        truncation.
265    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
267    7.  Added two (int) casts to pcregrep when printing the difference of two
268        pointers, in case they are 64-bit values.
270    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
271        test 2 if it fails.
273    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
274        and a #define of that name to empty if it is not externally set. This is to
275        allow users of MSVC to set it if necessary.
277    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
278        the convenience functions in the pcre_get.c source file.
280    11. An option change at the start of a pattern that had top-level alternatives
281        could cause overwriting and/or a crash. This command provoked a crash in
282        some environments:
284          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
286        This potential security problem was recorded as CVE-2008-2371.
288    12. For a pattern where the match had to start at the beginning or immediately
289        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
290        pcre_dfa_exec() could read past the end of the passed subject if there was
291        no match. To help with detecting such bugs (e.g. with valgrind), I modified
292        pcretest so that it places the subject at the end of its malloc-ed buffer.
294    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
295        exec() might read past the end of the data buffer in UTF-8 mode.
297    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
298        the data contained the byte 0x85 as part of a UTF-8 character within its
299        first line. This applied both to normal and DFA matching.
301    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
302        /^[^d]*?$/8 failed to match "abc".
304    16. Added a missing copyright notice to pcrecpp_internal.h.
306    17. Make it more clear in the documentation that values returned from
307        pcre_exec() in ovector are byte offsets, not character counts.
309    18. Tidied a few places to stop certain compilers from issuing warnings.
311    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
312        supplied by Stefan Weber. I made a further small update for 7.8 because
313        there is a change of source arrangements: the pcre_searchfuncs.c module is
314        replaced by pcre_ucd.c.
317    Version 7.7 07-May-08
318    ---------------------
320    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
321        a string to a long long, pretend we don't even have a long long." This is
322        done by checking for the strtoq, strtoll, and _strtoi64 functions.
324    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
325        pre-7.6 versions, which defined a global no_arg variable instead of putting
326        it in the RE class. (See also #8 below.)
328    3.  Remove a line of dead code, identified by coverity and reported by Nuno
329        Lopes.
331    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
333        (1) The include/exclude patterns were being applied to the whole pathnames
334            of files, instead of just to the final components.
336        (2) If there was more than one level of directory, the subdirectories were
337            skipped unless they satisfied the include/exclude conditions. This is
338            inconsistent with GNU grep (and could even be seen as contrary to the
339            pcregrep specification - which I improved to make it absolutely clear).
340            The action now is always to scan all levels of directory, and just
341            apply the include/exclude patterns to regular files.
343    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
344        --exclude_dir in the tests to avoid scanning .svn directories.
346    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
347        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
348        doesn't support NULs in patterns.
350    7.  Added some missing "const"s to declarations of static tables in
351        pcre_compile.c and pcre_dfa_exec.c.
353    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
354        caused by fix #2  above. (Subsequently also a second patch to fix the
355        first patch. And a third patch - this was a messy problem.)
357    9.  Applied Craig's patch to remove the use of push_back().
359    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
360        matching function regexec().
362    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
363        which, however, unlike Perl's \g{...}, are subroutine calls, not back
364        references. PCRE supports relative numbers with this syntax (I don't think
365        Oniguruma does).
367    12. Previously, a group with a zero repeat such as (...){0} was completely
368        omitted from the compiled regex. However, this means that if the group
369        was called as a subroutine from elsewhere in the pattern, things went wrong
370        (an internal error was given). Such groups are now left in the compiled
371        pattern, with a new opcode that causes them to be skipped at execution
372        time.
374    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
375        to the way PCRE behaves:
377        (a) A lone ] character is dis-allowed (Perl treats it as data).
379        (b) A back reference to an unmatched subpattern matches an empty string
380            (Perl fails the current match path).
382        (c) A data ] in a character class must be notated as \] because if the
383            first data character in a class is ], it defines an empty class. (In
384            Perl it is not possible to have an empty class.) The empty class []
385            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
386            The negative empty class [^] matches any one character, independently
387            of the DOTALL setting.
389    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
390        non-existent subpattern following a character class starting with ']' and
391        containing () gave an internal compiling error instead of "reference to
392        non-existent subpattern". Fortunately, when the pattern did exist, the
393        compiled code was correct. (When scanning forwards to check for the
394        existencd of the subpattern, it was treating the data ']' as terminating
395        the class, so got the count wrong. When actually compiling, the reference
396        was subsequently set up correctly.)
398    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
399        it was being rejected as not supported by pcre_dfa_exec(), even though
400        other assertions are supported. I have made pcre_dfa_exec() support
401        (*FAIL).
403    16. The implementation of 13c above involved the invention of a new opcode,
404        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
405        cannot be changed at match time, I realized I could make a small
406        improvement to matching performance by compiling OP_ALLANY instead of
407        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
408        on the OP_ANY path.
410    17. Compiling pcretest on Windows with readline support failed without the
411        following two fixes: (1) Make the unistd.h include conditional on
412        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
414    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
415        ncurses library to be included for pcretest when ReadLine support is
416        requested, but also to allow for it to be overridden. This patch came from
417        Daniel Bergström.
419    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
420        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
421        any errors with the current Unicode tables. Thanks to Peter Kankowski for
422        spotting this.
425    Version 7.6 28-Jan-08
426    ---------------------
428    1.  A character class containing a very large number of characters with
429        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
430        overflow.
432    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
433        HAVE_LONG_LONG is not defined.
435    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
436        bring them up to date and include new features. This patch includes:
438        - Fixed PH's badly added libz and libbz2 support.
439        - Fixed a problem with static linking.
440        - Added pcredemo. [But later removed - see 7 below.]
441        - Fixed dftables problem and added an option.
442        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
443            HAVE_LONG_LONG.
444        - Added readline support for pcretest.
445        - Added an listing of the option settings after cmake has run.
447    4.  A user submitted a patch to Makefile that makes it easy to create
448        "pcre.dll" under mingw when using Configure/Make. I added stuff to
449        Makefile.am that cause it to include this special target, without
450        affecting anything else. Note that the same mingw target plus all
451        the other distribution libraries and programs are now supported
452        when configuring with CMake (see 6 below) instead of with
453        Configure/Make.
455    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
456        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
457        exported in the Windows port". It has not yet been confirmed that the patch
458        solves the problem, but it does no harm.
460    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
461        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
462        with CMake, and also correct the comment about stack recursion.
464    7.  Remove the automatic building of pcredemo from the ./configure system and
465        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
466        of a program that users should build themselves after PCRE is installed, so
467        building it automatically is not really right. What is more, it gave
468        trouble in some build environments.
470    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
473    Version 7.5 10-Jan-08
474    ---------------------
476    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
477        values in parens when parsing an RE using the C++ wrapper."
479    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
480        Characters greater than 255 were excluded from the class instead of being
481        included.
483    3.  The same bug as (2) above applied to negated POSIX classes such as
484        [:^space:].
486    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
487        defined or documented. It seems to have been a typo for PCRE_STATIC, so
488        I have changed it.
490    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
491        first named subpattern) and a construct such as (?&a) would reference the
492        first named subpattern whose name started with "a" (in other words, the
493        length check was missing). Both these problems are fixed. "Subpattern name
494        expected" is now given for (?&) (a zero-length name), and this patch also
495        makes it give the same error for \k'' (previously it complained that that
496        was a reference to a non-existent subpattern).
498    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
499        this is right because (?- can be followed by option settings as well as by
500        digits. I have, however, made the messages clearer.
502    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
503        than the number used in the conditional) now cause a compile-time error.
504        This is actually not compatible with Perl, which accepts such patterns, but
505        treats the conditional as always being FALSE (as PCRE used to), but it
506        seems to me that giving a diagnostic is better.
508    8.  Change "alphameric" to the more common word "alphanumeric" in comments
509        and messages.
511    9.  Fix two occurrences of "backslash" in comments that should have been
512        "backspace".
514    10. Remove two redundant lines of code that can never be obeyed (their function
515        was moved elsewhere).
517    11. The program that makes PCRE's Unicode character property table had a bug
518        which caused it to generate incorrect table entries for sequences of
519        characters that have the same character type, but are in different scripts.
520        It amalgamated them into a single range, with the script of the first of
521        them. In other words, some characters were in the wrong script. There were
522        thirteen such cases, affecting characters in the following ranges:
524          U+002b0 - U+002c1
525          U+0060c - U+0060d
526          U+0061e - U+00612
527          U+0064b - U+0065e
528          U+0074d - U+0076d
529          U+01800 - U+01805
530          U+01d00 - U+01d77
531          U+01d9b - U+01dbf
532          U+0200b - U+0200f
533          U+030fc - U+030fe
534          U+03260 - U+0327f
535          U+0fb46 - U+0fbb1
536          U+10450 - U+1049d
538    12. The -o option (show only the matching part of a line) for pcregrep was not
539        compatible with GNU grep in that, if there was more than one match in a
540        line, it showed only the first of them. It now behaves in the same way as
541        GNU grep.
543    13. If the -o and -v options were combined for pcregrep, it printed a blank
544        line for every non-matching line. GNU grep prints nothing, and pcregrep now
545        does the same. The return code can be used to tell if there were any
546        non-matching lines.
548    14. Added --file-offsets and --line-offsets to pcregrep.
550    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
551        infinitely looping recursion. The bug was that positive lookaheads were not
552        being skipped when checking for a possible empty match (negative lookaheads
553        and both kinds of lookbehind were skipped).
555    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
556        inclusion of <windows.h> to before rather than after the definition of
557        INVALID_FILE_ATTRIBUTES (patch from David Byron).
559    17. Specifying a possessive quantifier with a specific limit for a Unicode
560        character property caused pcre_compile() to compile bad code, which led at
561        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
562        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
563        caused the error; without that there was no problem.
565    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
567    19. Added --enable-pcretest-libreadline.
569    20. In pcrecpp.cc, the variable 'count' was incremented twice in
570        RE::GlobalReplace(). As a result, the number of replacements returned was
571        double what it should be. I removed one of the increments, but Craig sent a
572        later patch that removed the other one (the right fix) and added unit tests
573        that check the return values (which was not done before).
575    21. Several CMake things:
577        (1) Arranged that, when cmake is used on Unix, the libraries end up with
578            the names libpcre and libpcreposix, not just pcre and pcreposix.
580        (2) The above change means that pcretest and pcregrep are now correctly
581            linked with the newly-built libraries, not previously installed ones.
585    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
586        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
587        UTF-8 newline character). The key issue is that the pattern starts .*;
588        this means that the match must be either at the beginning, or after a
589        newline. The bug was in the code for advancing after a failed match and
590        checking that the new position followed a newline. It was not taking
591        account of UTF-8 characters correctly.
593    23. PCRE was behaving differently from Perl in the way it recognized POSIX
594        character classes. PCRE was not treating the sequence [:...:] as a
595        character class unless the ... were all letters. Perl, however, seems to
596        allow any characters between [: and :], though of course it rejects as
597        unknown any "names" that contain non-letters, because all the known class
598        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
599        for example, whereas PCRE did not - it did not recognize a POSIX character
600        class. This seemed a bit dangerous, so the code has been changed to be
601        closer to Perl. The behaviour is not identical to Perl, because PCRE will
602        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
603        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
604        Perl does, and where it didn't before.
606    24. Rewrite so as to remove the single use of %n from pcregrep because in some
607        Windows environments %n is disabled by default.
610    Version 7.4 21-Sep-07
611    ---------------------
613    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
614        means that a class such as [\s] counted as "explicit reference to CR or
615        LF". That isn't really right - the whole point of the change was to try to
616        help when there was an actual mention of one of the two characters. So now
617        the change happens only if \r or \n (or a literal CR or LF) character is
618        encountered.
620    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
621        of both had grown to the point where there were only 3 bits left.
622        Fortunately, there was spare space in the data structure, and so I have
623        moved the internal flags into a new 16-bit field to free up more option
624        bits.
626    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
627        but did not set the internal JCHANGED flag - either of these is enough to
628        control the way the "get" function works - but the PCRE_INFO_JCHANGED
629        facility is supposed to tell if (?J) was ever used, so now (?J) at the
630        start sets both bits.
632    4.  Added options (at build time, compile time, exec time) to change \R from
633        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
635    5.  doc/pcresyntax.html was missing from the distribution.
637    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
638        compatibility, even though it is no longer used.
640    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
641        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
642        windows.h file is present (where different names are used). [This was
643        reversed later after testing - see 16 below.]
645    8.  Changed all #include <config.h> to #include "config.h". There were also
646        some further <pcre.h> cases that I changed to "pcre.h".
648    9.  When pcregrep was used with the --colour option, it missed the line ending
649        sequence off the lines that it output.
651    10. It was pointed out to me that arrays of string pointers cause lots of
652        relocations when a shared library is dynamically loaded. A technique of
653        using a single long string with a table of offsets can drastically reduce
654        these. I have refactored PCRE in four places to do this. The result is
655        dramatic:
657          Originally:                          290
658          After changing UCP table:            187
659          After changing error message table:   43
660          After changing table of "verbs"       36
661          After changing table of Posix names   22
663        Thanks to the folks working on Gregex for glib for this insight.
665    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
666        unicode-properties was also set.
668    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
670    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
671        checked only for CRLF.
673    14. Added casts to pcretest.c to avoid compiler warnings.
675    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
677    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
678        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
679        entirely. This removes changes made in 7 above.
681    17. The CMake files have been updated, and there is now more information about
682        building with CMake in the NON-UNIX-USE document.
685    Version 7.3 28-Aug-07
686    ---------------------
688     1. In the rejigging of the build system that eventually resulted in 7.1, the
689        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
690        brackets there is not right, since it causes compilers to look for an
691        installed pcre.h, not the version that is in the source that is being
692        compiled (which of course may be different). I have changed it back to:
694          #include "pcre.h"
696        I have a vague recollection that the change was concerned with compiling in
697        different directories, but in the new build system, that is taken care of
698        by the VPATH setting the Makefile.
700     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
701        when the subject happened to end in the byte 0x85 (e.g. if the last
702        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
703        characters but of course it shouldn't be taken as a newline when it is part
704        of another character. The bug was that, for an unlimited repeat of . in
705        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
706        characters when looking for a newline.
708     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
710     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
711        in debug output.
713     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
714        long printing in the pcrecpp unittest when running under MinGW.
716     6. ESC_K was left out of the EBCDIC table.
718     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
719        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
720        limit also applies to "virtual nesting" when a pattern is recursive, and in
721        this case 1000 isn't so big. I have been able to remove this limit at the
722        expense of backing off one optimization in certain circumstances. Normally,
723        when pcre_exec() would call its internal match() function recursively and
724        immediately return the result unconditionally, it uses a "tail recursion"
725        feature to save stack. However, when a subpattern that can match an empty
726        string has an unlimited repetition quantifier, it no longer makes this
727        optimization. That gives it a stack frame in which to save the data for
728        checking that an empty string has been matched. Previously this was taken
729        from the 1000-entry workspace that had been reserved. So now there is no
730        explicit limit, but more stack is used.
732     8. Applied Daniel's patches to solve problems with the import/export magic
733        syntax that is required for Windows, and which was going wrong for the
734        pcreposix and pcrecpp parts of the library. These were overlooked when this
735        problem was solved for the main library.
737     9. There were some crude static tests to avoid integer overflow when computing
738        the size of patterns that contain repeated groups with explicit upper
739        limits. As the maximum quantifier is 65535, the maximum group length was
740        set at 30,000 so that the product of these two numbers did not overflow a
741        32-bit integer. However, it turns out that people want to use groups that
742        are longer than 30,000 bytes (though not repeat them that many times).
743        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
744        made it possible to implement the integer overflow checks in a much more
745        dynamic way, which I have now done. The artificial limitation on group
746        length has been removed - we now have only the limit on the total length of
747        the compiled pattern, which depends on the LINK_SIZE setting.
749    10. Fixed a bug in the documentation for get/copy named substring when
750        duplicate names are permitted. If none of the named substrings are set, the
751        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
752        empty string.
754    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
755        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
756        because the ] is interpreted as the first data character and the
757        terminating ] is not found. PCRE has been made compatible with Perl in this
758        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
759        cause memory overwriting.
761    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
762        string has been matched (to stop an infinite loop). It was not recognizing
763        a conditional subpattern that could match an empty string if that
764        subpattern was within another subpattern. For example, it looped when
765        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
766        condition was not nested. This bug has been fixed.
768    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
769        past the start of the subject in the presence of bytes with the top bit
770        set, for example "\x8aBCD".
772    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
773        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
775    14. Optimized (?!) to (*FAIL).
777    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
778        This restricts code points to be within the range 0 to 0x10FFFF, excluding
779        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
780        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
781        does: it's just the validity check that is more restrictive.
783    16. Inserted checks for integer overflows during escape sequence (backslash)
784        processing, and also fixed erroneous offset values for syntax errors during
785        backslash processing.
787    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
788        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
790    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
791        caused an overrun.
793    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
794        something other than just ASCII characters) inside a group that had an
795        unlimited repeat caused a loop at compile time (while checking to see
796        whether the group could match an empty string).
798    20. Debugging a pattern containing \p or \P could cause a crash. For example,
799        [\P{Any}] did so. (Error in the code for printing property names.)
801    21. An orphan \E inside a character class could cause a crash.
803    22. A repeated capturing bracket such as (A)? could cause a wild memory
804        reference during compilation.
806    23. There are several functions in pcre_compile() that scan along a compiled
807        expression for various reasons (e.g. to see if it's fixed length for look
808        behind). There were bugs in these functions when a repeated \p or \P was
809        present in the pattern. These operators have additional parameters compared
810        with \d, etc, and these were not being taken into account when moving along
811        the compiled data. Specifically:
813        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
814            length.
816        (b) An item such as \pL+ within a repeated group could cause crashes or
817            loops.
819        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
820            "reference to non-existent subpattern" error.
822        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
824    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
825        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
827    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
829    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
830        character were causing crashes (broken optimization).
832    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
833        \p or \P) caused a compile-time loop.
835    28. More problems have arisen in unanchored patterns when CRLF is a valid line
836        break. For example, the unstudied pattern [\r\n]A does not match the string
837        "\r\nA" because change 7.0/46 below moves the current point on by two
838        characters after failing to match at the start. However, the pattern \nA
839        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
840        the same is true. There doesn't seem any very clean way out of this, but
841        what I have chosen to do makes the common cases work: PCRE now takes note
842        of whether there can be an explicit match for \r or \n anywhere in the
843        pattern, and if so, 7.0/46 no longer applies. As part of this change,
844        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
845        pattern has explicit CR or LF references.
847    29. Added (*CR) etc for changing newline setting at start of pattern.
850    Version 7.2 19-Jun-07
851    ---------------------
853     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
854        which is apparently normally available under Windows.
856     2. Re-jig the pcregrep tests with different newline settings in an attempt
857        to make them independent of the local environment's newline setting.
859     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
861     4. Some of the "internals" tests were previously cut out when the link size
862        was not 2, because the output contained actual offsets. The recent new
863        "Z" feature of pcretest means that these can be cut out, making the tests
864        usable with all link sizes.
866     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
867        stack recursion. This gives a massive performance boost under BSD, but just
868        a small improvement under Linux. However, it saves one field in the frame
869        in all cases.
871     6. Added more features from the forthcoming Perl 5.10:
873        (a) (?-n) (where n is a string of digits) is a relative subroutine or
874            recursion call. It refers to the nth most recently opened parentheses.
876        (b) (?+n) is also a relative subroutine call; it refers to the nth next
877            to be opened parentheses.
879        (c) Conditions that refer to capturing parentheses can be specified
880            relatively, for example, (?(-2)... or (?(+3)...
882        (d) \K resets the start of the current match so that everything before
883            is not part of it.
885        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
887        (f) \g{name} is another synonym - part of Perl 5.10's unification of
888            reference syntax.
890        (g) (?| introduces a group in which the numbering of parentheses in each
891            alternative starts with the same number.
893        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
895     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
898     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
899        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
900        for detecting groups that can match an empty string.
902     9. A pattern with a very large number of alternatives (more than several
903        hundred) was running out of internal workspace during the pre-compile
904        phase, where pcre_compile() figures out how much memory will be needed. A
905        bit of new cunning has reduced the workspace needed for groups with
906        alternatives. The 1000-alternative test pattern now uses 12 bytes of
907        workspace instead of running out of the 4096 that are available.
909    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
911    11. Applied patch from Google to remove an optimization that didn't quite work.
912        The report of the bug said:
914          pcrecpp::RE("a*").FullMatch("aaa") matches, while
915          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
916          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
918    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
919        it matched the wrong number of bytes.
922    Version 7.1 24-Apr-07
923    ---------------------
925     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
926        that is more "standard", making use of automake and other Autotools. There
927        is some re-arrangement of the files and adjustment of comments consequent
928        on this.
930     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
931        for recursive directory scanning broke on some systems because the files
932        are not scanned in any specific order and on different systems the order
933        was different. A call to "sort" has been inserted into RunGrepTest for the
934        approprate test as a short-term fix. In the longer term there may be an
935        alternative.
937     3. I had an email from Eric Raymond about problems translating some of PCRE's
938        man pages to HTML (despite the fact that I distribute HTML pages, some
939        people do their own conversions for various reasons). The problems
940        concerned the use of low-level troff macros .br and .in. I have therefore
941        removed all such uses from the man pages (some were redundant, some could
942        be replaced by .nf/.fi pairs). The 132html script that I use to generate
943        HTML has been updated to handle .nf/.fi and to complain if it encounters
944        .br or .in.
946     4. Updated comments in configure.ac that get placed in config.h.in and also
947        arranged for config.h to be included in the distribution, with the name
948        config.h.generic, for the benefit of those who have to compile without
949        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
951     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
952        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
953        makevp.bat for the current PCRE, using the additional files
954        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
956     6. A Windows user reported a minor discrepancy with test 2, which turned out
957        to be caused by a trailing space on an input line that had got lost in his
958        copy. The trailing space was an accident, so I've just removed it.
960     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
961        that is needed.
963     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
964        as "const" (a) because they are and (b) because it helps the PHP
965        maintainers who have recently made a script to detect big data structures
966        in the php code that should be moved to the .rodata section. I remembered
967        to update Builducptable as well, so it won't revert if ucptable.h is ever
968        re-created.
970     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
971        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
972        order to be able to cut out the UTF-8 tables in the latter when UTF-8
973        support is not required. This saves 1.5-2K of code, which is important in
974        some applications.
976        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
977        so as not to refer to the tables, even though these functions will never be
978        called when UTF-8 support is disabled. Otherwise there are problems with a
979        shared library.
981    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
983        (a) It was defining its arguments as char * instead of void *.
985        (b) It was assuming that all moves were upwards in memory; this was true
986            a long time ago when I wrote it, but is no longer the case.
988        The emulated memove() is provided for those environments that have neither
989        memmove() nor bcopy(). I didn't think anyone used it these days, but that
990        is clearly not the case, as these two bugs were recently reported.
992    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
993        and Detrail to create the HTML documentation, the .txt form of the man
994        pages, and it removes trailing spaces from listed files. It also creates
995        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
996        case, it wraps all the #defines with #ifndefs. This script should be run
997        before "make dist".
999    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1000        with Unicode property support.
1002        (a) For a maximizing quantifier, if the two different cases of the
1003            character were of different lengths in their UTF-8 codings (there are
1004            some cases like this - I found 11), and the matching function had to
1005            back up over a mixture of the two cases, it incorrectly assumed they
1006            were both the same length.
1008        (b) When PCRE was configured to use the heap rather than the stack for
1009            recursion during matching, it was not correctly preserving the data for
1010            the other case of a UTF-8 character when checking ahead for a match
1011            while processing a minimizing repeat. If the check also involved
1012            matching a wide character, but failed, corruption could cause an
1013            erroneous result when trying to check for a repeat of the original
1014            character.
1016    13. Some tidying changes to the testing mechanism:
1018        (a) The RunTest script now detects the internal link size and whether there
1019            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1020            values substituted by "configure". (The RunGrepTest script already did
1021            this for UTF-8.) The configure.ac script no longer substitutes the
1022            relevant variables.
1024        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1025            with length and offset values. This means that the output is different
1026            for different internal link sizes. Test 2 is skipped for link sizes
1027            other than 2 because of this, bypassing the problem. Unfortunately,
1028            there was also a test in test 3 (the locale tests) that used /B and
1029            failed for link sizes other than 2. Rather than cut the whole test out,
1030            I have added a new /Z option to pcretest that replaces the length and
1031            offset values with spaces. This is now used to make test 3 independent
1032            of link size. (Test 2 will be tidied up later.)
1034    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1035        segmentation fault instead of returning the appropriate error message.
1037    15. In multiline mode when the newline sequence was set to "any", the pattern
1038        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1039        This doesn't seem right; it now treats the CRLF combination as the line
1040        ending, and so does not match in that case. It's only a pattern such as ^$
1041        that would hit this one: something like ^ABC$ would have failed after \r
1042        and then tried again after \r\n.
1044    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1045        in an attempt to make files that differ only in their line terminators
1046        compare equal. This works on Linux.
1048    17. Under certain error circumstances pcregrep might try to free random memory
1049        as it exited. This is now fixed, thanks to valgrind.
1051    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1052        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1053        was because its rules for how to advance for /g after matching an empty
1054        string at the end of a line did not allow for this case. They now check for
1055        it specially.
1057    20. pcretest is supposed to handle patterns and data of any length, by
1058        extending its buffers when necessary. It was getting this wrong when the
1059        buffer for a data line had to be extended.
1061    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1062        CRLF as a newline sequence.
1064    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1065        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1066        I have nevertheless tidied it up.
1068    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1070    24. Added a man page for pcre-config.
1073    Version 7.0 19-Dec-06
1074    ---------------------
1076     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1077        moving to gcc 4.1.1.
1079     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1080        sys/time.h, which is documented as needed for this function. It doesn't
1081        seem to matter on Linux, but it showed up on some releases of OS X.
1083     3. It seems that there are systems where bytes whose values are greater than
1084        127 match isprint() in the "C" locale. The "C" locale should be the
1085        default when a C program starts up. In most systems, only ASCII printing
1086        characters match isprint(). This difference caused the output from pcretest
1087        to vary, making some of the tests fail. I have changed pcretest so that:
1089        (a) When it is outputting text in the compiled version of a pattern, bytes
1090            other than 32-126 are always shown as hex escapes.
1092        (b) When it is outputting text that is a matched part of a subject string,
1093            it does the same, unless a different locale has been set for the match
1094            (using the /L modifier). In this case, it uses isprint() to decide.
1096     4. Fixed a major bug that caused incorrect computation of the amount of memory
1097        required for a compiled pattern when options that changed within the
1098        pattern affected the logic of the preliminary scan that determines the
1099        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1100        that the computed length was too small. The symptoms of this bug were
1101        either the PCRE error "internal error: code overflow" from pcre_compile(),
1102        or a glibc crash with a message such as "pcretest: free(): invalid next
1103        size (fast)". Examples of patterns that provoked this bug (shown in
1104        pcretest format) are:
1106          /(?-x: )/x
1107          /(?x)(?-x: \s*#\s*)/
1108          /((?i)[\x{c0}])/8
1109          /(?i:[\x{c0}])/8
1111        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1112        is now done differently.
1114     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1115        wrapper classes; (b) implement a new function in the C++ scanner that is
1116        more efficient than the old way of doing things because it avoids levels of
1117        recursion in the regex matching; (c) add a paragraph to the documentation
1118        for the FullMatch() function.
1120     6. The escape sequence \n was being treated as whatever was defined as
1121        "newline". Not only was this contrary to the documentation, which states
1122        that \n is character 10 (hex 0A), but it also went horribly wrong when
1123        "newline" was defined as CRLF. This has been fixed.
1125     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1126        was being set to -1 for the "end of line" case (supposedly a value that no
1127        character can have). Though this value is never used (the check for end of
1128        line is "zero bytes in current character"), it caused compiler complaints.
1129        I've changed it to 0xffffffff.
1131     8. In pcre_version.c, the version string was being built by a sequence of
1132        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1133        string (as it is for production releases) called a macro with an empty
1134        argument. The C standard says the result of this is undefined. The gcc
1135        compiler treats it as an empty string (which was what was wanted) but it is
1136        reported that Visual C gives an error. The source has been hacked around to
1137        avoid this problem.
1139     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1140        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1141        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1142        of them did).
1144    10. Originally, pcretest opened its input and output without "b"; then I was
1145        told that "b" was needed in some environments, so it was added for release
1146        5.0 to both the input and output. (It makes no difference on Unix-like
1147        systems.) Later I was told that it is wrong for the input on Windows. I've
1148        now abstracted the modes into two macros, to make it easier to fiddle with
1149        them, and removed "b" from the input mode under Windows.
1151    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1153    12. Added -help and --help to pcretest as an official way of being reminded
1154        of the options.
1156    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1157        and pcrecpp.cc because they annoy compilers at high warning levels.
1159    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1161    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1162        scripts are not C programs :-) and which was not noticed because it works
1163        on Linux.
1165    16. pcretest is supposed to handle any length of pattern and data line (as one
1166        line or as a continued sequence of lines) by extending its input buffer if
1167        necessary. This feature was broken for very long pattern lines, leading to
1168        a string of junk being passed to pcre_compile() if the pattern was longer
1169        than about 50K.
1171    17. I have done a major re-factoring of the way pcre_compile() computes the
1172        amount of memory needed for a compiled pattern. Previously, there was code
1173        that made a preliminary scan of the pattern in order to do this. That was
1174        OK when PCRE was new, but as the facilities have expanded, it has become
1175        harder and harder to keep it in step with the real compile phase, and there
1176        have been a number of bugs (see for example, 4 above). I have now found a
1177        cunning way of running the real compile function in a "fake" mode that
1178        enables it to compute how much memory it would need, while actually only
1179        ever using a few hundred bytes of working memory and without too many
1180        tests of the mode. This should make future maintenance and development
1181        easier. A side effect of this work is that the limit of 200 on the nesting
1182        depth of parentheses has been removed (though this was never a serious
1183        limitation, I suspect). However, there is a downside: pcre_compile() now
1184        runs more slowly than before (30% or more, depending on the pattern). I
1185        hope this isn't a big issue. There is no effect on runtime performance.
1187    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1188        newline (only possible for the last line of a file) and it was a
1189        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1191    19. Added additional timing features to pcretest. (1) The -tm option now times
1192        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1193        separate command line item, by a number that specifies the number of
1194        repeats to use when timing. The default is 50000; this gives better
1195        precision, but takes uncomfortably long for very large patterns.
1197    20. Extended pcre_study() to be more clever in cases where a branch of a
1198        subpattern has no definite first character. For example, (a*|b*)[cd] would
1199        previously give no result from pcre_study(). Now it recognizes that the
1200        first character must be a, b, c, or d.
1202    21. There was an incorrect error "recursive call could loop indefinitely" if
1203        a subpattern (or the entire pattern) that was being tested for matching an
1204        empty string contained only one non-empty item after a nested subpattern.
1205        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1206        incorrectly, because the \d was being skipped in the check.
1208    22. The pcretest program now has a new pattern option /B and a command line
1209        option -b, which is equivalent to adding /B to every pattern. This causes
1210        it to show the compiled bytecode, without the additional information that
1211        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1212        is the same as /B/I).
1214    23. A new optimization is now able automatically to treat some sequences such
1215        as a*b as a*+b. More specifically, if something simple (such as a character
1216        or a simple class like \d) has an unlimited quantifier, and is followed by
1217        something that cannot possibly match the quantified thing, the quantifier
1218        is automatically "possessified".
1220    24. A recursive reference to a subpattern whose number was greater than 39
1221        went wrong under certain circumstances in UTF-8 mode. This bug could also
1222        have affected the operation of pcre_study().
1224    25. Realized that a little bit of performance could be had by replacing
1225        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1227    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1229    27. Possessive quantifiers such as a++ were previously implemented by turning
1230        them into atomic groups such as ($>a+). Now they have their own opcodes,
1231        which improves performance. This includes the automatically created ones
1232        from 23 above.
1234    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1235        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1236        the first matched character to be a colon. This applied both to named and
1237        numbered groups.
1239    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1241    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1242        building PCRE on Windows easier, so I have included it in the distribution.
1244    31. There is now a check in pcretest against a ridiculously large number being
1245        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1246        loop, the loop is abandoned.
1248    32. Forward references to subpatterns in conditions such as (?(2)...) where
1249        subpattern 2 is defined later cause pcre_compile() to search forwards in
1250        the pattern for the relevant set of parentheses. This search went wrong
1251        when there were unescaped parentheses in a character class, parentheses
1252        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1254    33. "Subroutine" calls and backreferences were previously restricted to
1255        referencing subpatterns earlier in the regex. This restriction has now
1256        been removed.
1258    34. Added a number of extra features that are going to be in Perl 5.10. On the
1259        whole, these are just syntactic alternatives for features that PCRE had
1260        previously implemented using the Python syntax or my own invention. The
1261        other formats are all retained for compatibility.
1263        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1264            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1265            also .NET compatible.
1267        (b) A recursion or subroutine call to a named group can now be defined as
1268            (?&name) as well as (?P>name).
1270        (c) A backreference to a named group can now be defined as \k<name> or
1271            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1272            5.10, are also .NET compatible.
1274        (d) A conditional reference to a named group can now use the syntax
1275            (?(<name>) or (?('name') as well as (?(name).
1277        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1278            groups (named and numbered) that are never evaluated inline, but can be
1279            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1280            is always false. There may be only one alternative in such a group.
1282        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1283            as the simple (?(R). The condition is true only if the most recent
1284            recursion is that of the given number or name. It does not search out
1285            through the entire recursion stack.
1287        (g) The escape \gN or \g{N} has been added, where N is a positive or
1288            negative number, specifying an absolute or relative reference.
1290    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1291        some "unreachable code" warnings.
1293    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1294        things, this adds five new scripts.
1296    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1297        There were also incompatibilities regarding the handling of \Q..\E inside
1298        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1299        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1301    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1302        matches an empty string, and forcibly breaks the loop. There were bugs in
1303        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1304        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1305        separate and independent bugs (that affected different cases) have been
1306        fixed.
1308    39. Refactored the code to abolish the use of different opcodes for small
1309        capturing bracket numbers. This is a tidy that I avoided doing when I
1310        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1311        The new approach is not only tidier, it makes it possible to reduce the
1312        memory needed to fix the previous bug (38).
1314    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1315        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1316        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1317        mode.
1319    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1320        report.
1322    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1323        copy construction and assignment in the C++ wrapper.
1325    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1326        couple of bugs that could have given wrong results in the "--newline=crlf"
1327        case.
1329    44. Added a number of casts and did some reorganization of signed/unsigned int
1330        variables following suggestions from Dair Grant. Also renamed the variable
1331        "this" as "item" because it is a C++ keyword.
1333    45. Arranged for dftables to add
1335          #include "pcre_internal.h"
1337        to pcre_chartables.c because without it, gcc 4.x may remove the array
1338        definition from the final binary if PCRE is built into a static library and
1339        dead code stripping is activated.
1341    46. For an unanchored pattern, if a match attempt fails at the start of a
1342        newline sequence, and the newline setting is CRLF or ANY, and the next two
1343        characters are CRLF, advance by two characters instead of one.
1346  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
1347  ---------------------  ---------------------

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