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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 431 by ph10, Wed Sep 2 09:23:21 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.00 ??-???-??
5    ----------------------
6    
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8        was out-of-date, and there was no check on the pcre_compile() error code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.
11    
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.
15    
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.
23    
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.
28    
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.
33    
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.
36    
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.
43    
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.
50    
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.
56    
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().
62    
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).
70    
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.
77    
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.
81    
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.
85    
86    
87    Version 7.9 11-Apr-09
88    ---------------------
89    
90    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
91        (pcretest), all targets were linked against these libraries. This included
92        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
93        libraries. This caused unwanted dependencies to be created. This problem
94        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
95        pcretest is linked with readline.
96    
97    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
98        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
99        moved outside it again, because FALSE and TRUE are already defined in AIX,
100        but BOOL is not.
101    
102    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
103        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
104    
105    4.  The pcregrep documentation said spaces were inserted as well as colons (or
106        hyphens) following file names and line numbers when outputting matching
107        lines. This is not true; no spaces are inserted. I have also clarified the
108        wording for the --colour (or --color) option.
109    
110    5.  In pcregrep, when --colour was used with -o, the list of matching strings
111        was not coloured; this is different to GNU grep, so I have changed it to be
112        the same.
113    
114    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
115        each matching line was coloured. Now it goes on to look for further matches
116        of any of the test patterns, which is the same behaviour as GNU grep.
117    
118    7.  A pattern that could match an empty string could cause pcregrep to loop; it
119        doesn't make sense to accept an empty string match in pcregrep, so I have
120        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
121        seems to be how GNU grep behaves.
122    
123    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
124        start or after a newline", because the conditional assertion was not being
125        correctly handled. The rule now is that both the assertion and what follows
126        in the first alternative must satisfy the test.
127    
128    9.  If auto-callout was enabled in a pattern with a conditional group whose
129        condition was an assertion, PCRE could crash during matching, both with
130        pcre_exec() and pcre_dfa_exec().
131    
132    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
133        used for matching.
134    
135    11. Unicode property support in character classes was not working for
136        characters (bytes) greater than 127 when not in UTF-8 mode.
137    
138    12. Added the -M command line option to pcretest.
139    
140    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
141    
142    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
143    
144    16. Added comments and documentation about mis-use of no_arg in the C++
145        wrapper.
146    
147    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
148        from Martin Jerabek that uses macro names for all relevant character and
149        string constants.
150    
151    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
152        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
153        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
154        these, but not everybody uses configure.
155    
156    19. A conditional group that had only one branch was not being correctly
157        recognized as an item that could match an empty string. This meant that an
158        enclosing group might also not be so recognized, causing infinite looping
159        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
160        with the subject "ab", where knowledge that the repeated group can match
161        nothing is needed in order to break the loop.
162    
163    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
164        exec(), but without supplying a callout function, matching went wrong.
165    
166    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
167        leak if the size of the offset vector was greater than 30. When the vector
168        is smaller, the saved offsets during recursion go onto a local stack
169        vector, but for larger vectors malloc() is used. It was failing to free
170        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
171        error, in fact).
172    
173    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
174        heapframe that is used only when UTF-8 support is enabled. This caused no
175        problem, but was untidy.
176    
177    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
178        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
179        included within another project.
180    
181    24. Steven Van Ingelgem's patches to add more options to the CMake support,
182        slightly modified by me:
183    
184          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
185              not building pcregrep.
186    
187          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
188              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
189    
190    25. Forward references, both numeric and by name, in patterns that made use of
191        duplicate group numbers, could behave incorrectly or give incorrect errors,
192        because when scanning forward to find the reference group, PCRE was not
193        taking into account the duplicate group numbers. A pattern such as
194        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
195    
196    26. Changed a few more instances of "const unsigned char *" to USPTR, making
197        the feature of a custom pointer more persuasive (as requested by a user).
198    
199    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
200        pcretest.c, inside #ifndefs, because it seems they are sometimes already
201        pre-defined.
202    
203    28. Added support for (*UTF8) at the start of a pattern.
204    
205    29. Arrange for flags added by the "release type" setting in CMake to be shown
206        in the configuration summary.
207    
208    
209    Version 7.8 05-Sep-08
210    ---------------------
211    
212    1.  Replaced UCP searching code with optimized version as implemented for Ad
213        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
214        stage table and inline lookup instead of a function, giving speed ups of 2
215        to 5 times on some simple patterns that I tested. Permission was given to
216        distribute the MultiStage2.py script that generates the tables (it's not in
217        the tarball, but is in the Subversion repository).
218    
219    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
220        scripts.
221    
222    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
223        a group with a zero qualifier. The result of the study could be incorrect,
224        or the function might crash, depending on the pattern.
225    
226    4.  Caseless matching was not working for non-ASCII characters in back
227        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
228        It now works when Unicode Property Support is available.
229    
230    5.  In pcretest, an escape such as \x{de} in the data was always generating
231        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
232        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
233        truncation.
234    
235    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
236    
237    7.  Added two (int) casts to pcregrep when printing the difference of two
238        pointers, in case they are 64-bit values.
239    
240    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
241        test 2 if it fails.
242    
243    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
244        and a #define of that name to empty if it is not externally set. This is to
245        allow users of MSVC to set it if necessary.
246    
247    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
248        the convenience functions in the pcre_get.c source file.
249    
250    11. An option change at the start of a pattern that had top-level alternatives
251        could cause overwriting and/or a crash. This command provoked a crash in
252        some environments:
253    
254          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
255    
256        This potential security problem was recorded as CVE-2008-2371.
257    
258    12. For a pattern where the match had to start at the beginning or immediately
259        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
260        pcre_dfa_exec() could read past the end of the passed subject if there was
261        no match. To help with detecting such bugs (e.g. with valgrind), I modified
262        pcretest so that it places the subject at the end of its malloc-ed buffer.
263    
264    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
265        exec() might read past the end of the data buffer in UTF-8 mode.
266    
267    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
268        the data contained the byte 0x85 as part of a UTF-8 character within its
269        first line. This applied both to normal and DFA matching.
270    
271    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
272        /^[^d]*?$/8 failed to match "abc".
273    
274    16. Added a missing copyright notice to pcrecpp_internal.h.
275    
276    17. Make it more clear in the documentation that values returned from
277        pcre_exec() in ovector are byte offsets, not character counts.
278    
279    18. Tidied a few places to stop certain compilers from issuing warnings.
280    
281    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
282        supplied by Stefan Weber. I made a further small update for 7.8 because
283        there is a change of source arrangements: the pcre_searchfuncs.c module is
284        replaced by pcre_ucd.c.
285    
286    
287    Version 7.7 07-May-08
288    ---------------------
289    
290    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
291        a string to a long long, pretend we don't even have a long long." This is
292        done by checking for the strtoq, strtoll, and _strtoi64 functions.
293    
294    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
295        pre-7.6 versions, which defined a global no_arg variable instead of putting
296        it in the RE class. (See also #8 below.)
297    
298    3.  Remove a line of dead code, identified by coverity and reported by Nuno
299        Lopes.
300    
301    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
302    
303        (1) The include/exclude patterns were being applied to the whole pathnames
304            of files, instead of just to the final components.
305    
306        (2) If there was more than one level of directory, the subdirectories were
307            skipped unless they satisfied the include/exclude conditions. This is
308            inconsistent with GNU grep (and could even be seen as contrary to the
309            pcregrep specification - which I improved to make it absolutely clear).
310            The action now is always to scan all levels of directory, and just
311            apply the include/exclude patterns to regular files.
312    
313    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
314        --exclude_dir in the tests to avoid scanning .svn directories.
315    
316    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
317        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
318        doesn't support NULs in patterns.
319    
320    7.  Added some missing "const"s to declarations of static tables in
321        pcre_compile.c and pcre_dfa_exec.c.
322    
323    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
324        caused by fix #2  above. (Subsequently also a second patch to fix the
325        first patch. And a third patch - this was a messy problem.)
326    
327    9.  Applied Craig's patch to remove the use of push_back().
328    
329    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
330        matching function regexec().
331    
332    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
333        which, however, unlike Perl's \g{...}, are subroutine calls, not back
334        references. PCRE supports relative numbers with this syntax (I don't think
335        Oniguruma does).
336    
337    12. Previously, a group with a zero repeat such as (...){0} was completely
338        omitted from the compiled regex. However, this means that if the group
339        was called as a subroutine from elsewhere in the pattern, things went wrong
340        (an internal error was given). Such groups are now left in the compiled
341        pattern, with a new opcode that causes them to be skipped at execution
342        time.
343    
344    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
345        to the way PCRE behaves:
346    
347        (a) A lone ] character is dis-allowed (Perl treats it as data).
348    
349        (b) A back reference to an unmatched subpattern matches an empty string
350            (Perl fails the current match path).
351    
352        (c) A data ] in a character class must be notated as \] because if the
353            first data character in a class is ], it defines an empty class. (In
354            Perl it is not possible to have an empty class.) The empty class []
355            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
356            The negative empty class [^] matches any one character, independently
357            of the DOTALL setting.
358    
359    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
360        non-existent subpattern following a character class starting with ']' and
361        containing () gave an internal compiling error instead of "reference to
362        non-existent subpattern". Fortunately, when the pattern did exist, the
363        compiled code was correct. (When scanning forwards to check for the
364        existencd of the subpattern, it was treating the data ']' as terminating
365        the class, so got the count wrong. When actually compiling, the reference
366        was subsequently set up correctly.)
367    
368    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
369        it was being rejected as not supported by pcre_dfa_exec(), even though
370        other assertions are supported. I have made pcre_dfa_exec() support
371        (*FAIL).
372    
373    16. The implementation of 13c above involved the invention of a new opcode,
374        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
375        cannot be changed at match time, I realized I could make a small
376        improvement to matching performance by compiling OP_ALLANY instead of
377        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
378        on the OP_ANY path.
379    
380    17. Compiling pcretest on Windows with readline support failed without the
381        following two fixes: (1) Make the unistd.h include conditional on
382        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
383    
384    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
385        ncurses library to be included for pcretest when ReadLine support is
386        requested, but also to allow for it to be overridden. This patch came from
387        Daniel Bergström.
388    
389    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
390        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
391        any errors with the current Unicode tables. Thanks to Peter Kankowski for
392        spotting this.
393    
394    
395    Version 7.6 28-Jan-08
396    ---------------------
397    
398    1.  A character class containing a very large number of characters with
399        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
400        overflow.
401    
402    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
403        HAVE_LONG_LONG is not defined.
404    
405    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
406        bring them up to date and include new features. This patch includes:
407    
408        - Fixed PH's badly added libz and libbz2 support.
409        - Fixed a problem with static linking.
410        - Added pcredemo. [But later removed - see 7 below.]
411        - Fixed dftables problem and added an option.
412        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
413            HAVE_LONG_LONG.
414        - Added readline support for pcretest.
415        - Added an listing of the option settings after cmake has run.
416    
417    4.  A user submitted a patch to Makefile that makes it easy to create
418        "pcre.dll" under mingw when using Configure/Make. I added stuff to
419        Makefile.am that cause it to include this special target, without
420        affecting anything else. Note that the same mingw target plus all
421        the other distribution libraries and programs are now supported
422        when configuring with CMake (see 6 below) instead of with
423        Configure/Make.
424    
425    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
426        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
427        exported in the Windows port". It has not yet been confirmed that the patch
428        solves the problem, but it does no harm.
429    
430    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
431        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
432        with CMake, and also correct the comment about stack recursion.
433    
434    7.  Remove the automatic building of pcredemo from the ./configure system and
435        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
436        of a program that users should build themselves after PCRE is installed, so
437        building it automatically is not really right. What is more, it gave
438        trouble in some build environments.
439    
440    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
441    
442    
443    Version 7.5 10-Jan-08
444    ---------------------
445    
446    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
447        values in parens when parsing an RE using the C++ wrapper."
448    
449    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
450        Characters greater than 255 were excluded from the class instead of being
451        included.
452    
453    3.  The same bug as (2) above applied to negated POSIX classes such as
454        [:^space:].
455    
456    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
457        defined or documented. It seems to have been a typo for PCRE_STATIC, so
458        I have changed it.
459    
460    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
461        first named subpattern) and a construct such as (?&a) would reference the
462        first named subpattern whose name started with "a" (in other words, the
463        length check was missing). Both these problems are fixed. "Subpattern name
464        expected" is now given for (?&) (a zero-length name), and this patch also
465        makes it give the same error for \k'' (previously it complained that that
466        was a reference to a non-existent subpattern).
467    
468    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
469        this is right because (?- can be followed by option settings as well as by
470        digits. I have, however, made the messages clearer.
471    
472    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
473        than the number used in the conditional) now cause a compile-time error.
474        This is actually not compatible with Perl, which accepts such patterns, but
475        treats the conditional as always being FALSE (as PCRE used to), but it
476        seems to me that giving a diagnostic is better.
477    
478    8.  Change "alphameric" to the more common word "alphanumeric" in comments
479        and messages.
480    
481    9.  Fix two occurrences of "backslash" in comments that should have been
482        "backspace".
483    
484    10. Remove two redundant lines of code that can never be obeyed (their function
485        was moved elsewhere).
486    
487    11. The program that makes PCRE's Unicode character property table had a bug
488        which caused it to generate incorrect table entries for sequences of
489        characters that have the same character type, but are in different scripts.
490        It amalgamated them into a single range, with the script of the first of
491        them. In other words, some characters were in the wrong script. There were
492        thirteen such cases, affecting characters in the following ranges:
493    
494          U+002b0 - U+002c1
495          U+0060c - U+0060d
496          U+0061e - U+00612
497          U+0064b - U+0065e
498          U+0074d - U+0076d
499          U+01800 - U+01805
500          U+01d00 - U+01d77
501          U+01d9b - U+01dbf
502          U+0200b - U+0200f
503          U+030fc - U+030fe
504          U+03260 - U+0327f
505          U+0fb46 - U+0fbb1
506          U+10450 - U+1049d
507    
508    12. The -o option (show only the matching part of a line) for pcregrep was not
509        compatible with GNU grep in that, if there was more than one match in a
510        line, it showed only the first of them. It now behaves in the same way as
511        GNU grep.
512    
513    13. If the -o and -v options were combined for pcregrep, it printed a blank
514        line for every non-matching line. GNU grep prints nothing, and pcregrep now
515        does the same. The return code can be used to tell if there were any
516        non-matching lines.
517    
518    14. Added --file-offsets and --line-offsets to pcregrep.
519    
520    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
521        infinitely looping recursion. The bug was that positive lookaheads were not
522        being skipped when checking for a possible empty match (negative lookaheads
523        and both kinds of lookbehind were skipped).
524    
525    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
526        inclusion of <windows.h> to before rather than after the definition of
527        INVALID_FILE_ATTRIBUTES (patch from David Byron).
528    
529    17. Specifying a possessive quantifier with a specific limit for a Unicode
530        character property caused pcre_compile() to compile bad code, which led at
531        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
532        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
533        caused the error; without that there was no problem.
534    
535    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
536    
537    19. Added --enable-pcretest-libreadline.
538    
539    20. In pcrecpp.cc, the variable 'count' was incremented twice in
540        RE::GlobalReplace(). As a result, the number of replacements returned was
541        double what it should be. I removed one of the increments, but Craig sent a
542        later patch that removed the other one (the right fix) and added unit tests
543        that check the return values (which was not done before).
544    
545    21. Several CMake things:
546    
547        (1) Arranged that, when cmake is used on Unix, the libraries end up with
548            the names libpcre and libpcreposix, not just pcre and pcreposix.
549    
550        (2) The above change means that pcretest and pcregrep are now correctly
551            linked with the newly-built libraries, not previously installed ones.
552    
553        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
554    
555    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
556        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
557        UTF-8 newline character). The key issue is that the pattern starts .*;
558        this means that the match must be either at the beginning, or after a
559        newline. The bug was in the code for advancing after a failed match and
560        checking that the new position followed a newline. It was not taking
561        account of UTF-8 characters correctly.
562    
563    23. PCRE was behaving differently from Perl in the way it recognized POSIX
564        character classes. PCRE was not treating the sequence [:...:] as a
565        character class unless the ... were all letters. Perl, however, seems to
566        allow any characters between [: and :], though of course it rejects as
567        unknown any "names" that contain non-letters, because all the known class
568        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
569        for example, whereas PCRE did not - it did not recognize a POSIX character
570        class. This seemed a bit dangerous, so the code has been changed to be
571        closer to Perl. The behaviour is not identical to Perl, because PCRE will
572        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
573        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
574        Perl does, and where it didn't before.
575    
576    24. Rewrite so as to remove the single use of %n from pcregrep because in some
577        Windows environments %n is disabled by default.
578    
579    
580    Version 7.4 21-Sep-07
581    ---------------------
582    
583    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
584        means that a class such as [\s] counted as "explicit reference to CR or
585        LF". That isn't really right - the whole point of the change was to try to
586        help when there was an actual mention of one of the two characters. So now
587        the change happens only if \r or \n (or a literal CR or LF) character is
588        encountered.
589    
590    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
591        of both had grown to the point where there were only 3 bits left.
592        Fortunately, there was spare space in the data structure, and so I have
593        moved the internal flags into a new 16-bit field to free up more option
594        bits.
595    
596    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
597        but did not set the internal JCHANGED flag - either of these is enough to
598        control the way the "get" function works - but the PCRE_INFO_JCHANGED
599        facility is supposed to tell if (?J) was ever used, so now (?J) at the
600        start sets both bits.
601    
602    4.  Added options (at build time, compile time, exec time) to change \R from
603        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
604    
605    5.  doc/pcresyntax.html was missing from the distribution.
606    
607    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
608        compatibility, even though it is no longer used.
609    
610    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
611        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
612        windows.h file is present (where different names are used). [This was
613        reversed later after testing - see 16 below.]
614    
615    8.  Changed all #include <config.h> to #include "config.h". There were also
616        some further <pcre.h> cases that I changed to "pcre.h".
617    
618    9.  When pcregrep was used with the --colour option, it missed the line ending
619        sequence off the lines that it output.
620    
621    10. It was pointed out to me that arrays of string pointers cause lots of
622        relocations when a shared library is dynamically loaded. A technique of
623        using a single long string with a table of offsets can drastically reduce
624        these. I have refactored PCRE in four places to do this. The result is
625        dramatic:
626    
627          Originally:                          290
628          After changing UCP table:            187
629          After changing error message table:   43
630          After changing table of "verbs"       36
631          After changing table of Posix names   22
632    
633        Thanks to the folks working on Gregex for glib for this insight.
634    
635    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
636        unicode-properties was also set.
637    
638    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
639    
640    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
641        checked only for CRLF.
642    
643    14. Added casts to pcretest.c to avoid compiler warnings.
644    
645    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
646    
647    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
648        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
649        entirely. This removes changes made in 7 above.
650    
651    17. The CMake files have been updated, and there is now more information about
652        building with CMake in the NON-UNIX-USE document.
653    
654    
655    Version 7.3 28-Aug-07
656    ---------------------
657    
658     1. In the rejigging of the build system that eventually resulted in 7.1, the
659        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
660        brackets there is not right, since it causes compilers to look for an
661        installed pcre.h, not the version that is in the source that is being
662        compiled (which of course may be different). I have changed it back to:
663    
664          #include "pcre.h"
665    
666        I have a vague recollection that the change was concerned with compiling in
667        different directories, but in the new build system, that is taken care of
668        by the VPATH setting the Makefile.
669    
670     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
671        when the subject happened to end in the byte 0x85 (e.g. if the last
672        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
673        characters but of course it shouldn't be taken as a newline when it is part
674        of another character. The bug was that, for an unlimited repeat of . in
675        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
676        characters when looking for a newline.
677    
678     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
679    
680     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
681        in debug output.
682    
683     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
684        long printing in the pcrecpp unittest when running under MinGW.
685    
686     6. ESC_K was left out of the EBCDIC table.
687    
688     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
689        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
690        limit also applies to "virtual nesting" when a pattern is recursive, and in
691        this case 1000 isn't so big. I have been able to remove this limit at the
692        expense of backing off one optimization in certain circumstances. Normally,
693        when pcre_exec() would call its internal match() function recursively and
694        immediately return the result unconditionally, it uses a "tail recursion"
695        feature to save stack. However, when a subpattern that can match an empty
696        string has an unlimited repetition quantifier, it no longer makes this
697        optimization. That gives it a stack frame in which to save the data for
698        checking that an empty string has been matched. Previously this was taken
699        from the 1000-entry workspace that had been reserved. So now there is no
700        explicit limit, but more stack is used.
701    
702     8. Applied Daniel's patches to solve problems with the import/export magic
703        syntax that is required for Windows, and which was going wrong for the
704        pcreposix and pcrecpp parts of the library. These were overlooked when this
705        problem was solved for the main library.
706    
707     9. There were some crude static tests to avoid integer overflow when computing
708        the size of patterns that contain repeated groups with explicit upper
709        limits. As the maximum quantifier is 65535, the maximum group length was
710        set at 30,000 so that the product of these two numbers did not overflow a
711        32-bit integer. However, it turns out that people want to use groups that
712        are longer than 30,000 bytes (though not repeat them that many times).
713        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
714        made it possible to implement the integer overflow checks in a much more
715        dynamic way, which I have now done. The artificial limitation on group
716        length has been removed - we now have only the limit on the total length of
717        the compiled pattern, which depends on the LINK_SIZE setting.
718    
719    10. Fixed a bug in the documentation for get/copy named substring when
720        duplicate names are permitted. If none of the named substrings are set, the
721        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
722        empty string.
723    
724    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
725        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
726        because the ] is interpreted as the first data character and the
727        terminating ] is not found. PCRE has been made compatible with Perl in this
728        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
729        cause memory overwriting.
730    
731    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
732        string has been matched (to stop an infinite loop). It was not recognizing
733        a conditional subpattern that could match an empty string if that
734        subpattern was within another subpattern. For example, it looped when
735        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
736        condition was not nested. This bug has been fixed.
737    
738    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
739        past the start of the subject in the presence of bytes with the top bit
740        set, for example "\x8aBCD".
741    
742    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
743        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
744    
745    14. Optimized (?!) to (*FAIL).
746    
747    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
748        This restricts code points to be within the range 0 to 0x10FFFF, excluding
749        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
750        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
751        does: it's just the validity check that is more restrictive.
752    
753    16. Inserted checks for integer overflows during escape sequence (backslash)
754        processing, and also fixed erroneous offset values for syntax errors during
755        backslash processing.
756    
757    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
758        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
759    
760    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
761        caused an overrun.
762    
763    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
764        something other than just ASCII characters) inside a group that had an
765        unlimited repeat caused a loop at compile time (while checking to see
766        whether the group could match an empty string).
767    
768    20. Debugging a pattern containing \p or \P could cause a crash. For example,
769        [\P{Any}] did so. (Error in the code for printing property names.)
770    
771    21. An orphan \E inside a character class could cause a crash.
772    
773    22. A repeated capturing bracket such as (A)? could cause a wild memory
774        reference during compilation.
775    
776    23. There are several functions in pcre_compile() that scan along a compiled
777        expression for various reasons (e.g. to see if it's fixed length for look
778        behind). There were bugs in these functions when a repeated \p or \P was
779        present in the pattern. These operators have additional parameters compared
780        with \d, etc, and these were not being taken into account when moving along
781        the compiled data. Specifically:
782    
783        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
784            length.
785    
786        (b) An item such as \pL+ within a repeated group could cause crashes or
787            loops.
788    
789        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
790            "reference to non-existent subpattern" error.
791    
792        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
793    
794    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
795        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
796    
797    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
798    
799    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
800        character were causing crashes (broken optimization).
801    
802    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
803        \p or \P) caused a compile-time loop.
804    
805    28. More problems have arisen in unanchored patterns when CRLF is a valid line
806        break. For example, the unstudied pattern [\r\n]A does not match the string
807        "\r\nA" because change 7.0/46 below moves the current point on by two
808        characters after failing to match at the start. However, the pattern \nA
809        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
810        the same is true. There doesn't seem any very clean way out of this, but
811        what I have chosen to do makes the common cases work: PCRE now takes note
812        of whether there can be an explicit match for \r or \n anywhere in the
813        pattern, and if so, 7.0/46 no longer applies. As part of this change,
814        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
815        pattern has explicit CR or LF references.
816    
817    29. Added (*CR) etc for changing newline setting at start of pattern.
818    
819    
820    Version 7.2 19-Jun-07
821    ---------------------
822    
823     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
824        which is apparently normally available under Windows.
825    
826     2. Re-jig the pcregrep tests with different newline settings in an attempt
827        to make them independent of the local environment's newline setting.
828    
829     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
830    
831     4. Some of the "internals" tests were previously cut out when the link size
832        was not 2, because the output contained actual offsets. The recent new
833        "Z" feature of pcretest means that these can be cut out, making the tests
834        usable with all link sizes.
835    
836     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
837        stack recursion. This gives a massive performance boost under BSD, but just
838        a small improvement under Linux. However, it saves one field in the frame
839        in all cases.
840    
841     6. Added more features from the forthcoming Perl 5.10:
842    
843        (a) (?-n) (where n is a string of digits) is a relative subroutine or
844            recursion call. It refers to the nth most recently opened parentheses.
845    
846        (b) (?+n) is also a relative subroutine call; it refers to the nth next
847            to be opened parentheses.
848    
849        (c) Conditions that refer to capturing parentheses can be specified
850            relatively, for example, (?(-2)... or (?(+3)...
851    
852        (d) \K resets the start of the current match so that everything before
853            is not part of it.
854    
855        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
856    
857        (f) \g{name} is another synonym - part of Perl 5.10's unification of
858            reference syntax.
859    
860        (g) (?| introduces a group in which the numbering of parentheses in each
861            alternative starts with the same number.
862    
863        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
864    
865     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
866        PCRE_INFO_JCHANGED.
867    
868     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
869        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
870        for detecting groups that can match an empty string.
871    
872     9. A pattern with a very large number of alternatives (more than several
873        hundred) was running out of internal workspace during the pre-compile
874        phase, where pcre_compile() figures out how much memory will be needed. A
875        bit of new cunning has reduced the workspace needed for groups with
876        alternatives. The 1000-alternative test pattern now uses 12 bytes of
877        workspace instead of running out of the 4096 that are available.
878    
879    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
880    
881    11. Applied patch from Google to remove an optimization that didn't quite work.
882        The report of the bug said:
883    
884          pcrecpp::RE("a*").FullMatch("aaa") matches, while
885          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
886          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
887    
888    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
889        it matched the wrong number of bytes.
890    
891    
892    Version 7.1 24-Apr-07
893    ---------------------
894    
895     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
896        that is more "standard", making use of automake and other Autotools. There
897        is some re-arrangement of the files and adjustment of comments consequent
898        on this.
899    
900     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
901        for recursive directory scanning broke on some systems because the files
902        are not scanned in any specific order and on different systems the order
903        was different. A call to "sort" has been inserted into RunGrepTest for the
904        approprate test as a short-term fix. In the longer term there may be an
905        alternative.
906    
907     3. I had an email from Eric Raymond about problems translating some of PCRE's
908        man pages to HTML (despite the fact that I distribute HTML pages, some
909        people do their own conversions for various reasons). The problems
910        concerned the use of low-level troff macros .br and .in. I have therefore
911        removed all such uses from the man pages (some were redundant, some could
912        be replaced by .nf/.fi pairs). The 132html script that I use to generate
913        HTML has been updated to handle .nf/.fi and to complain if it encounters
914        .br or .in.
915    
916     4. Updated comments in configure.ac that get placed in config.h.in and also
917        arranged for config.h to be included in the distribution, with the name
918        config.h.generic, for the benefit of those who have to compile without
919        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
920    
921     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
922        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
923        makevp.bat for the current PCRE, using the additional files
924        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
925    
926     6. A Windows user reported a minor discrepancy with test 2, which turned out
927        to be caused by a trailing space on an input line that had got lost in his
928        copy. The trailing space was an accident, so I've just removed it.
929    
930     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
931        that is needed.
932    
933     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
934        as "const" (a) because they are and (b) because it helps the PHP
935        maintainers who have recently made a script to detect big data structures
936        in the php code that should be moved to the .rodata section. I remembered
937        to update Builducptable as well, so it won't revert if ucptable.h is ever
938        re-created.
939    
940     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
941        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
942        order to be able to cut out the UTF-8 tables in the latter when UTF-8
943        support is not required. This saves 1.5-2K of code, which is important in
944        some applications.
945    
946        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
947        so as not to refer to the tables, even though these functions will never be
948        called when UTF-8 support is disabled. Otherwise there are problems with a
949        shared library.
950    
951    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
952    
953        (a) It was defining its arguments as char * instead of void *.
954    
955        (b) It was assuming that all moves were upwards in memory; this was true
956            a long time ago when I wrote it, but is no longer the case.
957    
958        The emulated memove() is provided for those environments that have neither
959        memmove() nor bcopy(). I didn't think anyone used it these days, but that
960        is clearly not the case, as these two bugs were recently reported.
961    
962    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
963        and Detrail to create the HTML documentation, the .txt form of the man
964        pages, and it removes trailing spaces from listed files. It also creates
965        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
966        case, it wraps all the #defines with #ifndefs. This script should be run
967        before "make dist".
968    
969    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
970        with Unicode property support.
971    
972        (a) For a maximizing quantifier, if the two different cases of the
973            character were of different lengths in their UTF-8 codings (there are
974            some cases like this - I found 11), and the matching function had to
975            back up over a mixture of the two cases, it incorrectly assumed they
976            were both the same length.
977    
978        (b) When PCRE was configured to use the heap rather than the stack for
979            recursion during matching, it was not correctly preserving the data for
980            the other case of a UTF-8 character when checking ahead for a match
981            while processing a minimizing repeat. If the check also involved
982            matching a wide character, but failed, corruption could cause an
983            erroneous result when trying to check for a repeat of the original
984            character.
985    
986    13. Some tidying changes to the testing mechanism:
987    
988        (a) The RunTest script now detects the internal link size and whether there
989            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
990            values substituted by "configure". (The RunGrepTest script already did
991            this for UTF-8.) The configure.ac script no longer substitutes the
992            relevant variables.
993    
994        (b) The debugging options /B and /D in pcretest show the compiled bytecode
995            with length and offset values. This means that the output is different
996            for different internal link sizes. Test 2 is skipped for link sizes
997            other than 2 because of this, bypassing the problem. Unfortunately,
998            there was also a test in test 3 (the locale tests) that used /B and
999            failed for link sizes other than 2. Rather than cut the whole test out,
1000            I have added a new /Z option to pcretest that replaces the length and
1001            offset values with spaces. This is now used to make test 3 independent
1002            of link size. (Test 2 will be tidied up later.)
1003    
1004    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1005        segmentation fault instead of returning the appropriate error message.
1006    
1007    15. In multiline mode when the newline sequence was set to "any", the pattern
1008        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1009        This doesn't seem right; it now treats the CRLF combination as the line
1010        ending, and so does not match in that case. It's only a pattern such as ^$
1011        that would hit this one: something like ^ABC$ would have failed after \r
1012        and then tried again after \r\n.
1013    
1014    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1015        in an attempt to make files that differ only in their line terminators
1016        compare equal. This works on Linux.
1017    
1018    17. Under certain error circumstances pcregrep might try to free random memory
1019        as it exited. This is now fixed, thanks to valgrind.
1020    
1021    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1022        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1023        was because its rules for how to advance for /g after matching an empty
1024        string at the end of a line did not allow for this case. They now check for
1025        it specially.
1026    
1027    20. pcretest is supposed to handle patterns and data of any length, by
1028        extending its buffers when necessary. It was getting this wrong when the
1029        buffer for a data line had to be extended.
1030    
1031    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1032        CRLF as a newline sequence.
1033    
1034    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1035        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1036        I have nevertheless tidied it up.
1037    
1038    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1039    
1040    24. Added a man page for pcre-config.
1041    
1042    
1043    Version 7.0 19-Dec-06
1044    ---------------------
1045    
1046     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1047        moving to gcc 4.1.1.
1048    
1049     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1050        sys/time.h, which is documented as needed for this function. It doesn't
1051        seem to matter on Linux, but it showed up on some releases of OS X.
1052    
1053     3. It seems that there are systems where bytes whose values are greater than
1054        127 match isprint() in the "C" locale. The "C" locale should be the
1055        default when a C program starts up. In most systems, only ASCII printing
1056        characters match isprint(). This difference caused the output from pcretest
1057        to vary, making some of the tests fail. I have changed pcretest so that:
1058    
1059        (a) When it is outputting text in the compiled version of a pattern, bytes
1060            other than 32-126 are always shown as hex escapes.
1061    
1062        (b) When it is outputting text that is a matched part of a subject string,
1063            it does the same, unless a different locale has been set for the match
1064            (using the /L modifier). In this case, it uses isprint() to decide.
1065    
1066     4. Fixed a major bug that caused incorrect computation of the amount of memory
1067        required for a compiled pattern when options that changed within the
1068        pattern affected the logic of the preliminary scan that determines the
1069        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1070        that the computed length was too small. The symptoms of this bug were
1071        either the PCRE error "internal error: code overflow" from pcre_compile(),
1072        or a glibc crash with a message such as "pcretest: free(): invalid next
1073        size (fast)". Examples of patterns that provoked this bug (shown in
1074        pcretest format) are:
1075    
1076          /(?-x: )/x
1077          /(?x)(?-x: \s*#\s*)/
1078          /((?i)[\x{c0}])/8
1079          /(?i:[\x{c0}])/8
1080    
1081        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1082        is now done differently.
1083    
1084     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1085        wrapper classes; (b) implement a new function in the C++ scanner that is
1086        more efficient than the old way of doing things because it avoids levels of
1087        recursion in the regex matching; (c) add a paragraph to the documentation
1088        for the FullMatch() function.
1089    
1090     6. The escape sequence \n was being treated as whatever was defined as
1091        "newline". Not only was this contrary to the documentation, which states
1092        that \n is character 10 (hex 0A), but it also went horribly wrong when
1093        "newline" was defined as CRLF. This has been fixed.
1094    
1095     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1096        was being set to -1 for the "end of line" case (supposedly a value that no
1097        character can have). Though this value is never used (the check for end of
1098        line is "zero bytes in current character"), it caused compiler complaints.
1099        I've changed it to 0xffffffff.
1100    
1101     8. In pcre_version.c, the version string was being built by a sequence of
1102        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1103        string (as it is for production releases) called a macro with an empty
1104        argument. The C standard says the result of this is undefined. The gcc
1105        compiler treats it as an empty string (which was what was wanted) but it is
1106        reported that Visual C gives an error. The source has been hacked around to
1107        avoid this problem.
1108    
1109     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1110        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1111        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1112        of them did).
1113    
1114    10. Originally, pcretest opened its input and output without "b"; then I was
1115        told that "b" was needed in some environments, so it was added for release
1116        5.0 to both the input and output. (It makes no difference on Unix-like
1117        systems.) Later I was told that it is wrong for the input on Windows. I've
1118        now abstracted the modes into two macros, to make it easier to fiddle with
1119        them, and removed "b" from the input mode under Windows.
1120    
1121    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1122    
1123    12. Added -help and --help to pcretest as an official way of being reminded
1124        of the options.
1125    
1126    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1127        and pcrecpp.cc because they annoy compilers at high warning levels.
1128    
1129    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1130    
1131    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1132        scripts are not C programs :-) and which was not noticed because it works
1133        on Linux.
1134    
1135    16. pcretest is supposed to handle any length of pattern and data line (as one
1136        line or as a continued sequence of lines) by extending its input buffer if
1137        necessary. This feature was broken for very long pattern lines, leading to
1138        a string of junk being passed to pcre_compile() if the pattern was longer
1139        than about 50K.
1140    
1141    17. I have done a major re-factoring of the way pcre_compile() computes the
1142        amount of memory needed for a compiled pattern. Previously, there was code
1143        that made a preliminary scan of the pattern in order to do this. That was
1144        OK when PCRE was new, but as the facilities have expanded, it has become
1145        harder and harder to keep it in step with the real compile phase, and there
1146        have been a number of bugs (see for example, 4 above). I have now found a
1147        cunning way of running the real compile function in a "fake" mode that
1148        enables it to compute how much memory it would need, while actually only
1149        ever using a few hundred bytes of working memory and without too many
1150        tests of the mode. This should make future maintenance and development
1151        easier. A side effect of this work is that the limit of 200 on the nesting
1152        depth of parentheses has been removed (though this was never a serious
1153        limitation, I suspect). However, there is a downside: pcre_compile() now
1154        runs more slowly than before (30% or more, depending on the pattern). I
1155        hope this isn't a big issue. There is no effect on runtime performance.
1156    
1157    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1158        newline (only possible for the last line of a file) and it was a
1159        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1160    
1161    19. Added additional timing features to pcretest. (1) The -tm option now times
1162        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1163        separate command line item, by a number that specifies the number of
1164        repeats to use when timing. The default is 50000; this gives better
1165        precision, but takes uncomfortably long for very large patterns.
1166    
1167    20. Extended pcre_study() to be more clever in cases where a branch of a
1168        subpattern has no definite first character. For example, (a*|b*)[cd] would
1169        previously give no result from pcre_study(). Now it recognizes that the
1170        first character must be a, b, c, or d.
1171    
1172    21. There was an incorrect error "recursive call could loop indefinitely" if
1173        a subpattern (or the entire pattern) that was being tested for matching an
1174        empty string contained only one non-empty item after a nested subpattern.
1175        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1176        incorrectly, because the \d was being skipped in the check.
1177    
1178    22. The pcretest program now has a new pattern option /B and a command line
1179        option -b, which is equivalent to adding /B to every pattern. This causes
1180        it to show the compiled bytecode, without the additional information that
1181        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1182        is the same as /B/I).
1183    
1184    23. A new optimization is now able automatically to treat some sequences such
1185        as a*b as a*+b. More specifically, if something simple (such as a character
1186        or a simple class like \d) has an unlimited quantifier, and is followed by
1187        something that cannot possibly match the quantified thing, the quantifier
1188        is automatically "possessified".
1189    
1190    24. A recursive reference to a subpattern whose number was greater than 39
1191        went wrong under certain circumstances in UTF-8 mode. This bug could also
1192        have affected the operation of pcre_study().
1193    
1194    25. Realized that a little bit of performance could be had by replacing
1195        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1196    
1197    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1198    
1199    27. Possessive quantifiers such as a++ were previously implemented by turning
1200        them into atomic groups such as ($>a+). Now they have their own opcodes,
1201        which improves performance. This includes the automatically created ones
1202        from 23 above.
1203    
1204    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1205        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1206        the first matched character to be a colon. This applied both to named and
1207        numbered groups.
1208    
1209    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1210    
1211    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1212        building PCRE on Windows easier, so I have included it in the distribution.
1213    
1214    31. There is now a check in pcretest against a ridiculously large number being
1215        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1216        loop, the loop is abandoned.
1217    
1218    32. Forward references to subpatterns in conditions such as (?(2)...) where
1219        subpattern 2 is defined later cause pcre_compile() to search forwards in
1220        the pattern for the relevant set of parentheses. This search went wrong
1221        when there were unescaped parentheses in a character class, parentheses
1222        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1223    
1224    33. "Subroutine" calls and backreferences were previously restricted to
1225        referencing subpatterns earlier in the regex. This restriction has now
1226        been removed.
1227    
1228    34. Added a number of extra features that are going to be in Perl 5.10. On the
1229        whole, these are just syntactic alternatives for features that PCRE had
1230        previously implemented using the Python syntax or my own invention. The
1231        other formats are all retained for compatibility.
1232    
1233        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1234            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1235            also .NET compatible.
1236    
1237        (b) A recursion or subroutine call to a named group can now be defined as
1238            (?&name) as well as (?P>name).
1239    
1240        (c) A backreference to a named group can now be defined as \k<name> or
1241            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1242            5.10, are also .NET compatible.
1243    
1244        (d) A conditional reference to a named group can now use the syntax
1245            (?(<name>) or (?('name') as well as (?(name).
1246    
1247        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1248            groups (named and numbered) that are never evaluated inline, but can be
1249            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1250            is always false. There may be only one alternative in such a group.
1251    
1252        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1253            as the simple (?(R). The condition is true only if the most recent
1254            recursion is that of the given number or name. It does not search out
1255            through the entire recursion stack.
1256    
1257        (g) The escape \gN or \g{N} has been added, where N is a positive or
1258            negative number, specifying an absolute or relative reference.
1259    
1260    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1261        some "unreachable code" warnings.
1262    
1263    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1264        things, this adds five new scripts.
1265    
1266    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1267        There were also incompatibilities regarding the handling of \Q..\E inside
1268        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1269        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1270    
1271    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1272        matches an empty string, and forcibly breaks the loop. There were bugs in
1273        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1274        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1275        separate and independent bugs (that affected different cases) have been
1276        fixed.
1277    
1278    39. Refactored the code to abolish the use of different opcodes for small
1279        capturing bracket numbers. This is a tidy that I avoided doing when I
1280        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1281        The new approach is not only tidier, it makes it possible to reduce the
1282        memory needed to fix the previous bug (38).
1283    
1284    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1285        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1286        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1287        mode.
1288    
1289    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1290        report.
1291    
1292    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1293        copy construction and assignment in the C++ wrapper.
1294    
1295    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1296        couple of bugs that could have given wrong results in the "--newline=crlf"
1297        case.
1298    
1299    44. Added a number of casts and did some reorganization of signed/unsigned int
1300        variables following suggestions from Dair Grant. Also renamed the variable
1301        "this" as "item" because it is a C++ keyword.
1302    
1303    45. Arranged for dftables to add
1304    
1305          #include "pcre_internal.h"
1306    
1307        to pcre_chartables.c because without it, gcc 4.x may remove the array
1308        definition from the final binary if PCRE is built into a static library and
1309        dead code stripping is activated.
1310    
1311    46. For an unanchored pattern, if a match attempt fails at the start of a
1312        newline sequence, and the newline setting is CRLF or ANY, and the next two
1313        characters are CRLF, advance by two characters instead of one.
1314    
1315    
1316    Version 6.7 04-Jul-06
1317    ---------------------
1318    
1319     1. In order to handle tests when input lines are enormously long, pcretest has
1320        been re-factored so that it automatically extends its buffers when
1321        necessary. The code is crude, but this _is_ just a test program. The
1322        default size has been increased from 32K to 50K.
1323    
1324     2. The code in pcre_study() was using the value of the re argument before
1325        testing it for NULL. (Of course, in any sensible call of the function, it
1326        won't be NULL.)
1327    
1328     3. The memmove() emulation function in pcre_internal.h, which is used on
1329        systems that lack both memmove() and bcopy() - that is, hardly ever -
1330        was missing a "static" storage class specifier.
1331    
1332     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1333        containing an extended class (one that cannot be represented by a bitmap
1334        because it contains high-valued characters or Unicode property items, e.g.
1335        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1336        pattern, but PCRE should not loop if you do not (it no longer does).
1337        [Detail: two cases were found: (a) a repeated subpattern containing an
1338        extended class; (b) a recursive reference to a subpattern that followed a
1339        previous extended class. It wasn't skipping over the extended class
1340        correctly when UTF-8 mode was not set.]
1341    
1342     5. A negated single-character class was not being recognized as fixed-length
1343        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1344        compile error "lookbehind assertion is not fixed length".
1345    
1346     6. The RunPerlTest auxiliary script was showing an unexpected difference
1347        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1348        write a Perl script that can interpret lines of an input file either as
1349        byte characters or as UTF-8, which is what "perltest" was being required to
1350        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1351        can't do is switch easily at run time between having the "use utf8;" pragma
1352        or not. In the end, I fudged it by using the RunPerlTest script to insert
1353        "use utf8;" explicitly for the UTF-8 tests.
1354    
1355     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1356        the end of the subject string, contrary to the documentation and to what
1357        Perl does. This was true of both matching functions. Now it matches only at
1358        the start of the subject and immediately after *internal* newlines.
1359    
1360     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1361        a pointer to an int instead of a pointer to an unsigned long int. This
1362        caused problems on 64-bit systems.
1363    
1364     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1365        instance of the 'standard' template library not being so standard".
1366    
1367    10. There was no check on the number of named subpatterns nor the maximum
1368        length of a subpattern name. The product of these values is used to compute
1369        the size of the memory block for a compiled pattern. By supplying a very
1370        long subpattern name and a large number of named subpatterns, the size
1371        computation could be caused to overflow. This is now prevented by limiting
1372        the length of names to 32 characters, and the number of named subpatterns
1373        to 10,000.
1374    
1375    11. Subpatterns that are repeated with specific counts have to be replicated in
1376        the compiled pattern. The size of memory for this was computed from the
1377        length of the subpattern and the repeat count. The latter is limited to
1378        65535, but there was no limit on the former, meaning that integer overflow
1379        could in principle occur. The compiled length of a repeated subpattern is
1380        now limited to 30,000 bytes in order to prevent this.
1381    
1382    12. Added the optional facility to have named substrings with the same name.
1383    
1384    13. Added the ability to use a named substring as a condition, using the
1385        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1386        are numbers (not recommended). Forward references are permitted.
1387    
1388    14. Added forward references in named backreferences (if you see what I mean).
1389    
1390    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1391        pattern could run off the end of the subject. For example, the pattern
1392        "(?s)(.{1,5})"8 did this with the subject "ab".
1393    
1394    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1395        PCRE_CASELESS was set when matching characters that were quantified with ?
1396        or *.
1397    
1398    17. A character class other than a single negated character that had a minimum
1399        but no maximum quantifier - for example [ab]{6,} - was not handled
1400        correctly by pce_dfa_exec(). It would match only one character.
1401    
1402    18. A valid (though odd) pattern that looked like a POSIX character
1403        class but used an invalid character after [ (for example [[,abc,]]) caused
1404        pcre_compile() to give the error "Failed: internal error: code overflow" or
1405        in some cases to crash with a glibc free() error. This could even happen if
1406        the pattern terminated after [[ but there just happened to be a sequence of
1407        letters, a binary zero, and a closing ] in the memory that followed.
1408    
1409    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1410        over the years. Originally (before any Unicode support), just the bottom 8
1411        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1412        output from "man perlunicode" includes this:
1413    
1414          The regular expression compiler produces polymorphic opcodes.  That
1415          is, the pattern adapts to the data and automatically switches to
1416          the Unicode character scheme when presented with Unicode data--or
1417          instead uses a traditional byte scheme when presented with byte
1418          data.
1419    
1420        Sadly, a wide octal escape does not cause a switch, and in a string with
1421        no other multibyte characters, these octal escapes are treated as before.
1422        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1423        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1424        Unicode string.
1425    
1426        I have not perpetrated such confusion in PCRE. Up till now, it took just
1427        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1428        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1429        translate to the appropriate multibyte character.
1430    
1431    29. Applied some refactoring to reduce the number of warnings from Microsoft
1432        and Borland compilers. This has included removing the fudge introduced
1433        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1434        a warning about an unused variable.
1435    
1436    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1437        characters since release 4.0, because Perl (from release 5.004) does not.
1438        [Or at least, is documented not to: some releases seem to be in conflict
1439        with the documentation.] However, when a pattern was studied with
1440        pcre_study() and all its branches started with \s, PCRE still included VT
1441        as a possible starting character. Of course, this did no harm; it just
1442        caused an unnecessary match attempt.
1443    
1444    22. Removed a now-redundant internal flag bit that recorded the fact that case
1445        dependency changed within the pattern. This was once needed for "required
1446        byte" processing, but is no longer used. This recovers a now-scarce options
1447        bit. Also moved the least significant internal flag bit to the most-
1448        significant bit of the word, which was not previously used (hangover from
1449        the days when it was an int rather than a uint) to free up another bit for
1450        the future.
1451    
1452    23. Added support for CRLF line endings as well as CR and LF. As well as the
1453        default being selectable at build time, it can now be changed at runtime
1454        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1455        specify that it is scanning data with non-default line endings.
1456    
1457    24. Changed the definition of CXXLINK to make it agree with the definition of
1458        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1459    
1460    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1461        recursions. This makes a big different to stack usage for some patterns.
1462    
1463    26. If a subpattern containing a named recursion or subroutine reference such
1464        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1465        the space required for the compiled pattern went wrong and gave too small a
1466        value. Depending on the environment, this could lead to "Failed: internal
1467        error: code overflow at offset 49" or "glibc detected double free or
1468        corruption" errors.
1469    
1470    27. Applied patches from Google (a) to support the new newline modes and (b) to
1471        advance over multibyte UTF-8 characters in GlobalReplace.
1472    
1473    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1474        difference for some implementation of PCRE in some Windows version.
1475    
1476    29. Added some extra testing facilities to pcretest:
1477    
1478        \q<number>   in a data line sets the "match limit" value
1479        \Q<number>   in a data line sets the "match recursion limt" value
1480        -S <number>  sets the stack size, where <number> is in megabytes
1481    
1482        The -S option isn't available for Windows.
1483    
1484    
1485    Version 6.6 06-Feb-06
1486    ---------------------
1487    
1488     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1489        in pcreposix.h. I have copied the definition from pcre.h.
1490    
1491     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1492        because pcre.h is no longer a built file.
1493    
1494     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1495        not normally included in the compiled code.
1496    
1497    
1498  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1499  ---------------------  ---------------------
1500    

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