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revision 81 by nigel, Sat Feb 24 21:40:59 2007 UTC revision 435 by ph10, Sat Sep 5 10:20:44 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8        was out-of-date, and there was no check on the pcre_compile() error code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 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.
57    
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().
63    
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).
71    
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.
78    
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.
85    
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.
89    
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.
93    
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.
98    
99    17. If a caller to the POSIX matching function regexec() passes a non-zero
100        value for \fInmatch\fP with a NULL value for \fIpmatch\fP, the value of
101        \fInmatch\fP is forced to zero.
102    
103    
104    Version 7.9 11-Apr-09
105    ---------------------
106    
107    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
108        (pcretest), all targets were linked against these libraries. This included
109        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
110        libraries. This caused unwanted dependencies to be created. This problem
111        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
112        pcretest is linked with readline.
113    
114    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
115        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
116        moved outside it again, because FALSE and TRUE are already defined in AIX,
117        but BOOL is not.
118    
119    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
120        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
121    
122    4.  The pcregrep documentation said spaces were inserted as well as colons (or
123        hyphens) following file names and line numbers when outputting matching
124        lines. This is not true; no spaces are inserted. I have also clarified the
125        wording for the --colour (or --color) option.
126    
127    5.  In pcregrep, when --colour was used with -o, the list of matching strings
128        was not coloured; this is different to GNU grep, so I have changed it to be
129        the same.
130    
131    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
132        each matching line was coloured. Now it goes on to look for further matches
133        of any of the test patterns, which is the same behaviour as GNU grep.
134    
135    7.  A pattern that could match an empty string could cause pcregrep to loop; it
136        doesn't make sense to accept an empty string match in pcregrep, so I have
137        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
138        seems to be how GNU grep behaves.
139    
140    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
141        start or after a newline", because the conditional assertion was not being
142        correctly handled. The rule now is that both the assertion and what follows
143        in the first alternative must satisfy the test.
144    
145    9.  If auto-callout was enabled in a pattern with a conditional group whose
146        condition was an assertion, PCRE could crash during matching, both with
147        pcre_exec() and pcre_dfa_exec().
148    
149    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
150        used for matching.
151    
152    11. Unicode property support in character classes was not working for
153        characters (bytes) greater than 127 when not in UTF-8 mode.
154    
155    12. Added the -M command line option to pcretest.
156    
157    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
158    
159    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
160    
161    16. Added comments and documentation about mis-use of no_arg in the C++
162        wrapper.
163    
164    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
165        from Martin Jerabek that uses macro names for all relevant character and
166        string constants.
167    
168    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
169        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
170        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
171        these, but not everybody uses configure.
172    
173    19. A conditional group that had only one branch was not being correctly
174        recognized as an item that could match an empty string. This meant that an
175        enclosing group might also not be so recognized, causing infinite looping
176        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
177        with the subject "ab", where knowledge that the repeated group can match
178        nothing is needed in order to break the loop.
179    
180    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
181        exec(), but without supplying a callout function, matching went wrong.
182    
183    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
184        leak if the size of the offset vector was greater than 30. When the vector
185        is smaller, the saved offsets during recursion go onto a local stack
186        vector, but for larger vectors malloc() is used. It was failing to free
187        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
188        error, in fact).
189    
190    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
191        heapframe that is used only when UTF-8 support is enabled. This caused no
192        problem, but was untidy.
193    
194    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
195        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
196        included within another project.
197    
198    24. Steven Van Ingelgem's patches to add more options to the CMake support,
199        slightly modified by me:
200    
201          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
202              not building pcregrep.
203    
204          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
205              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
206    
207    25. Forward references, both numeric and by name, in patterns that made use of
208        duplicate group numbers, could behave incorrectly or give incorrect errors,
209        because when scanning forward to find the reference group, PCRE was not
210        taking into account the duplicate group numbers. A pattern such as
211        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
212    
213    26. Changed a few more instances of "const unsigned char *" to USPTR, making
214        the feature of a custom pointer more persuasive (as requested by a user).
215    
216    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
217        pcretest.c, inside #ifndefs, because it seems they are sometimes already
218        pre-defined.
219    
220    28. Added support for (*UTF8) at the start of a pattern.
221    
222    29. Arrange for flags added by the "release type" setting in CMake to be shown
223        in the configuration summary.
224    
225    
226    Version 7.8 05-Sep-08
227    ---------------------
228    
229    1.  Replaced UCP searching code with optimized version as implemented for Ad
230        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
231        stage table and inline lookup instead of a function, giving speed ups of 2
232        to 5 times on some simple patterns that I tested. Permission was given to
233        distribute the MultiStage2.py script that generates the tables (it's not in
234        the tarball, but is in the Subversion repository).
235    
236    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
237        scripts.
238    
239    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
240        a group with a zero qualifier. The result of the study could be incorrect,
241        or the function might crash, depending on the pattern.
242    
243    4.  Caseless matching was not working for non-ASCII characters in back
244        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
245        It now works when Unicode Property Support is available.
246    
247    5.  In pcretest, an escape such as \x{de} in the data was always generating
248        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
249        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
250        truncation.
251    
252    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
253    
254    7.  Added two (int) casts to pcregrep when printing the difference of two
255        pointers, in case they are 64-bit values.
256    
257    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
258        test 2 if it fails.
259    
260    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
261        and a #define of that name to empty if it is not externally set. This is to
262        allow users of MSVC to set it if necessary.
263    
264    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
265        the convenience functions in the pcre_get.c source file.
266    
267    11. An option change at the start of a pattern that had top-level alternatives
268        could cause overwriting and/or a crash. This command provoked a crash in
269        some environments:
270    
271          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
272    
273        This potential security problem was recorded as CVE-2008-2371.
274    
275    12. For a pattern where the match had to start at the beginning or immediately
276        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
277        pcre_dfa_exec() could read past the end of the passed subject if there was
278        no match. To help with detecting such bugs (e.g. with valgrind), I modified
279        pcretest so that it places the subject at the end of its malloc-ed buffer.
280    
281    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
282        exec() might read past the end of the data buffer in UTF-8 mode.
283    
284    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
285        the data contained the byte 0x85 as part of a UTF-8 character within its
286        first line. This applied both to normal and DFA matching.
287    
288    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
289        /^[^d]*?$/8 failed to match "abc".
290    
291    16. Added a missing copyright notice to pcrecpp_internal.h.
292    
293    17. Make it more clear in the documentation that values returned from
294        pcre_exec() in ovector are byte offsets, not character counts.
295    
296    18. Tidied a few places to stop certain compilers from issuing warnings.
297    
298    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
299        supplied by Stefan Weber. I made a further small update for 7.8 because
300        there is a change of source arrangements: the pcre_searchfuncs.c module is
301        replaced by pcre_ucd.c.
302    
303    
304    Version 7.7 07-May-08
305    ---------------------
306    
307    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
308        a string to a long long, pretend we don't even have a long long." This is
309        done by checking for the strtoq, strtoll, and _strtoi64 functions.
310    
311    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
312        pre-7.6 versions, which defined a global no_arg variable instead of putting
313        it in the RE class. (See also #8 below.)
314    
315    3.  Remove a line of dead code, identified by coverity and reported by Nuno
316        Lopes.
317    
318    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
319    
320        (1) The include/exclude patterns were being applied to the whole pathnames
321            of files, instead of just to the final components.
322    
323        (2) If there was more than one level of directory, the subdirectories were
324            skipped unless they satisfied the include/exclude conditions. This is
325            inconsistent with GNU grep (and could even be seen as contrary to the
326            pcregrep specification - which I improved to make it absolutely clear).
327            The action now is always to scan all levels of directory, and just
328            apply the include/exclude patterns to regular files.
329    
330    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
331        --exclude_dir in the tests to avoid scanning .svn directories.
332    
333    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
334        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
335        doesn't support NULs in patterns.
336    
337    7.  Added some missing "const"s to declarations of static tables in
338        pcre_compile.c and pcre_dfa_exec.c.
339    
340    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
341        caused by fix #2  above. (Subsequently also a second patch to fix the
342        first patch. And a third patch - this was a messy problem.)
343    
344    9.  Applied Craig's patch to remove the use of push_back().
345    
346    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
347        matching function regexec().
348    
349    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
350        which, however, unlike Perl's \g{...}, are subroutine calls, not back
351        references. PCRE supports relative numbers with this syntax (I don't think
352        Oniguruma does).
353    
354    12. Previously, a group with a zero repeat such as (...){0} was completely
355        omitted from the compiled regex. However, this means that if the group
356        was called as a subroutine from elsewhere in the pattern, things went wrong
357        (an internal error was given). Such groups are now left in the compiled
358        pattern, with a new opcode that causes them to be skipped at execution
359        time.
360    
361    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
362        to the way PCRE behaves:
363    
364        (a) A lone ] character is dis-allowed (Perl treats it as data).
365    
366        (b) A back reference to an unmatched subpattern matches an empty string
367            (Perl fails the current match path).
368    
369        (c) A data ] in a character class must be notated as \] because if the
370            first data character in a class is ], it defines an empty class. (In
371            Perl it is not possible to have an empty class.) The empty class []
372            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
373            The negative empty class [^] matches any one character, independently
374            of the DOTALL setting.
375    
376    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
377        non-existent subpattern following a character class starting with ']' and
378        containing () gave an internal compiling error instead of "reference to
379        non-existent subpattern". Fortunately, when the pattern did exist, the
380        compiled code was correct. (When scanning forwards to check for the
381        existencd of the subpattern, it was treating the data ']' as terminating
382        the class, so got the count wrong. When actually compiling, the reference
383        was subsequently set up correctly.)
384    
385    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
386        it was being rejected as not supported by pcre_dfa_exec(), even though
387        other assertions are supported. I have made pcre_dfa_exec() support
388        (*FAIL).
389    
390    16. The implementation of 13c above involved the invention of a new opcode,
391        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
392        cannot be changed at match time, I realized I could make a small
393        improvement to matching performance by compiling OP_ALLANY instead of
394        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
395        on the OP_ANY path.
396    
397    17. Compiling pcretest on Windows with readline support failed without the
398        following two fixes: (1) Make the unistd.h include conditional on
399        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
400    
401    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
402        ncurses library to be included for pcretest when ReadLine support is
403        requested, but also to allow for it to be overridden. This patch came from
404        Daniel Bergström.
405    
406    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
407        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
408        any errors with the current Unicode tables. Thanks to Peter Kankowski for
409        spotting this.
410    
411    
412    Version 7.6 28-Jan-08
413    ---------------------
414    
415    1.  A character class containing a very large number of characters with
416        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
417        overflow.
418    
419    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
420        HAVE_LONG_LONG is not defined.
421    
422    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
423        bring them up to date and include new features. This patch includes:
424    
425        - Fixed PH's badly added libz and libbz2 support.
426        - Fixed a problem with static linking.
427        - Added pcredemo. [But later removed - see 7 below.]
428        - Fixed dftables problem and added an option.
429        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
430            HAVE_LONG_LONG.
431        - Added readline support for pcretest.
432        - Added an listing of the option settings after cmake has run.
433    
434    4.  A user submitted a patch to Makefile that makes it easy to create
435        "pcre.dll" under mingw when using Configure/Make. I added stuff to
436        Makefile.am that cause it to include this special target, without
437        affecting anything else. Note that the same mingw target plus all
438        the other distribution libraries and programs are now supported
439        when configuring with CMake (see 6 below) instead of with
440        Configure/Make.
441    
442    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
443        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
444        exported in the Windows port". It has not yet been confirmed that the patch
445        solves the problem, but it does no harm.
446    
447    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
448        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
449        with CMake, and also correct the comment about stack recursion.
450    
451    7.  Remove the automatic building of pcredemo from the ./configure system and
452        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
453        of a program that users should build themselves after PCRE is installed, so
454        building it automatically is not really right. What is more, it gave
455        trouble in some build environments.
456    
457    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
458    
459    
460    Version 7.5 10-Jan-08
461    ---------------------
462    
463    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
464        values in parens when parsing an RE using the C++ wrapper."
465    
466    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
467        Characters greater than 255 were excluded from the class instead of being
468        included.
469    
470    3.  The same bug as (2) above applied to negated POSIX classes such as
471        [:^space:].
472    
473    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
474        defined or documented. It seems to have been a typo for PCRE_STATIC, so
475        I have changed it.
476    
477    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
478        first named subpattern) and a construct such as (?&a) would reference the
479        first named subpattern whose name started with "a" (in other words, the
480        length check was missing). Both these problems are fixed. "Subpattern name
481        expected" is now given for (?&) (a zero-length name), and this patch also
482        makes it give the same error for \k'' (previously it complained that that
483        was a reference to a non-existent subpattern).
484    
485    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
486        this is right because (?- can be followed by option settings as well as by
487        digits. I have, however, made the messages clearer.
488    
489    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
490        than the number used in the conditional) now cause a compile-time error.
491        This is actually not compatible with Perl, which accepts such patterns, but
492        treats the conditional as always being FALSE (as PCRE used to), but it
493        seems to me that giving a diagnostic is better.
494    
495    8.  Change "alphameric" to the more common word "alphanumeric" in comments
496        and messages.
497    
498    9.  Fix two occurrences of "backslash" in comments that should have been
499        "backspace".
500    
501    10. Remove two redundant lines of code that can never be obeyed (their function
502        was moved elsewhere).
503    
504    11. The program that makes PCRE's Unicode character property table had a bug
505        which caused it to generate incorrect table entries for sequences of
506        characters that have the same character type, but are in different scripts.
507        It amalgamated them into a single range, with the script of the first of
508        them. In other words, some characters were in the wrong script. There were
509        thirteen such cases, affecting characters in the following ranges:
510    
511          U+002b0 - U+002c1
512          U+0060c - U+0060d
513          U+0061e - U+00612
514          U+0064b - U+0065e
515          U+0074d - U+0076d
516          U+01800 - U+01805
517          U+01d00 - U+01d77
518          U+01d9b - U+01dbf
519          U+0200b - U+0200f
520          U+030fc - U+030fe
521          U+03260 - U+0327f
522          U+0fb46 - U+0fbb1
523          U+10450 - U+1049d
524    
525    12. The -o option (show only the matching part of a line) for pcregrep was not
526        compatible with GNU grep in that, if there was more than one match in a
527        line, it showed only the first of them. It now behaves in the same way as
528        GNU grep.
529    
530    13. If the -o and -v options were combined for pcregrep, it printed a blank
531        line for every non-matching line. GNU grep prints nothing, and pcregrep now
532        does the same. The return code can be used to tell if there were any
533        non-matching lines.
534    
535    14. Added --file-offsets and --line-offsets to pcregrep.
536    
537    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
538        infinitely looping recursion. The bug was that positive lookaheads were not
539        being skipped when checking for a possible empty match (negative lookaheads
540        and both kinds of lookbehind were skipped).
541    
542    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
543        inclusion of <windows.h> to before rather than after the definition of
544        INVALID_FILE_ATTRIBUTES (patch from David Byron).
545    
546    17. Specifying a possessive quantifier with a specific limit for a Unicode
547        character property caused pcre_compile() to compile bad code, which led at
548        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
549        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
550        caused the error; without that there was no problem.
551    
552    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
553    
554    19. Added --enable-pcretest-libreadline.
555    
556    20. In pcrecpp.cc, the variable 'count' was incremented twice in
557        RE::GlobalReplace(). As a result, the number of replacements returned was
558        double what it should be. I removed one of the increments, but Craig sent a
559        later patch that removed the other one (the right fix) and added unit tests
560        that check the return values (which was not done before).
561    
562    21. Several CMake things:
563    
564        (1) Arranged that, when cmake is used on Unix, the libraries end up with
565            the names libpcre and libpcreposix, not just pcre and pcreposix.
566    
567        (2) The above change means that pcretest and pcregrep are now correctly
568            linked with the newly-built libraries, not previously installed ones.
569    
570        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
571    
572    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
573        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
574        UTF-8 newline character). The key issue is that the pattern starts .*;
575        this means that the match must be either at the beginning, or after a
576        newline. The bug was in the code for advancing after a failed match and
577        checking that the new position followed a newline. It was not taking
578        account of UTF-8 characters correctly.
579    
580    23. PCRE was behaving differently from Perl in the way it recognized POSIX
581        character classes. PCRE was not treating the sequence [:...:] as a
582        character class unless the ... were all letters. Perl, however, seems to
583        allow any characters between [: and :], though of course it rejects as
584        unknown any "names" that contain non-letters, because all the known class
585        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
586        for example, whereas PCRE did not - it did not recognize a POSIX character
587        class. This seemed a bit dangerous, so the code has been changed to be
588        closer to Perl. The behaviour is not identical to Perl, because PCRE will
589        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
590        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
591        Perl does, and where it didn't before.
592    
593    24. Rewrite so as to remove the single use of %n from pcregrep because in some
594        Windows environments %n is disabled by default.
595    
596    
597    Version 7.4 21-Sep-07
598    ---------------------
599    
600    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
601        means that a class such as [\s] counted as "explicit reference to CR or
602        LF". That isn't really right - the whole point of the change was to try to
603        help when there was an actual mention of one of the two characters. So now
604        the change happens only if \r or \n (or a literal CR or LF) character is
605        encountered.
606    
607    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
608        of both had grown to the point where there were only 3 bits left.
609        Fortunately, there was spare space in the data structure, and so I have
610        moved the internal flags into a new 16-bit field to free up more option
611        bits.
612    
613    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
614        but did not set the internal JCHANGED flag - either of these is enough to
615        control the way the "get" function works - but the PCRE_INFO_JCHANGED
616        facility is supposed to tell if (?J) was ever used, so now (?J) at the
617        start sets both bits.
618    
619    4.  Added options (at build time, compile time, exec time) to change \R from
620        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
621    
622    5.  doc/pcresyntax.html was missing from the distribution.
623    
624    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
625        compatibility, even though it is no longer used.
626    
627    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
628        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
629        windows.h file is present (where different names are used). [This was
630        reversed later after testing - see 16 below.]
631    
632    8.  Changed all #include <config.h> to #include "config.h". There were also
633        some further <pcre.h> cases that I changed to "pcre.h".
634    
635    9.  When pcregrep was used with the --colour option, it missed the line ending
636        sequence off the lines that it output.
637    
638    10. It was pointed out to me that arrays of string pointers cause lots of
639        relocations when a shared library is dynamically loaded. A technique of
640        using a single long string with a table of offsets can drastically reduce
641        these. I have refactored PCRE in four places to do this. The result is
642        dramatic:
643    
644          Originally:                          290
645          After changing UCP table:            187
646          After changing error message table:   43
647          After changing table of "verbs"       36
648          After changing table of Posix names   22
649    
650        Thanks to the folks working on Gregex for glib for this insight.
651    
652    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
653        unicode-properties was also set.
654    
655    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
656    
657    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
658        checked only for CRLF.
659    
660    14. Added casts to pcretest.c to avoid compiler warnings.
661    
662    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
663    
664    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
665        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
666        entirely. This removes changes made in 7 above.
667    
668    17. The CMake files have been updated, and there is now more information about
669        building with CMake in the NON-UNIX-USE document.
670    
671    
672    Version 7.3 28-Aug-07
673    ---------------------
674    
675     1. In the rejigging of the build system that eventually resulted in 7.1, the
676        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
677        brackets there is not right, since it causes compilers to look for an
678        installed pcre.h, not the version that is in the source that is being
679        compiled (which of course may be different). I have changed it back to:
680    
681          #include "pcre.h"
682    
683        I have a vague recollection that the change was concerned with compiling in
684        different directories, but in the new build system, that is taken care of
685        by the VPATH setting the Makefile.
686    
687     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
688        when the subject happened to end in the byte 0x85 (e.g. if the last
689        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
690        characters but of course it shouldn't be taken as a newline when it is part
691        of another character. The bug was that, for an unlimited repeat of . in
692        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
693        characters when looking for a newline.
694    
695     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
696    
697     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
698        in debug output.
699    
700     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
701        long printing in the pcrecpp unittest when running under MinGW.
702    
703     6. ESC_K was left out of the EBCDIC table.
704    
705     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
706        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
707        limit also applies to "virtual nesting" when a pattern is recursive, and in
708        this case 1000 isn't so big. I have been able to remove this limit at the
709        expense of backing off one optimization in certain circumstances. Normally,
710        when pcre_exec() would call its internal match() function recursively and
711        immediately return the result unconditionally, it uses a "tail recursion"
712        feature to save stack. However, when a subpattern that can match an empty
713        string has an unlimited repetition quantifier, it no longer makes this
714        optimization. That gives it a stack frame in which to save the data for
715        checking that an empty string has been matched. Previously this was taken
716        from the 1000-entry workspace that had been reserved. So now there is no
717        explicit limit, but more stack is used.
718    
719     8. Applied Daniel's patches to solve problems with the import/export magic
720        syntax that is required for Windows, and which was going wrong for the
721        pcreposix and pcrecpp parts of the library. These were overlooked when this
722        problem was solved for the main library.
723    
724     9. There were some crude static tests to avoid integer overflow when computing
725        the size of patterns that contain repeated groups with explicit upper
726        limits. As the maximum quantifier is 65535, the maximum group length was
727        set at 30,000 so that the product of these two numbers did not overflow a
728        32-bit integer. However, it turns out that people want to use groups that
729        are longer than 30,000 bytes (though not repeat them that many times).
730        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
731        made it possible to implement the integer overflow checks in a much more
732        dynamic way, which I have now done. The artificial limitation on group
733        length has been removed - we now have only the limit on the total length of
734        the compiled pattern, which depends on the LINK_SIZE setting.
735    
736    10. Fixed a bug in the documentation for get/copy named substring when
737        duplicate names are permitted. If none of the named substrings are set, the
738        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
739        empty string.
740    
741    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
742        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
743        because the ] is interpreted as the first data character and the
744        terminating ] is not found. PCRE has been made compatible with Perl in this
745        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
746        cause memory overwriting.
747    
748    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
749        string has been matched (to stop an infinite loop). It was not recognizing
750        a conditional subpattern that could match an empty string if that
751        subpattern was within another subpattern. For example, it looped when
752        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
753        condition was not nested. This bug has been fixed.
754    
755    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
756        past the start of the subject in the presence of bytes with the top bit
757        set, for example "\x8aBCD".
758    
759    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
760        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
761    
762    14. Optimized (?!) to (*FAIL).
763    
764    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
765        This restricts code points to be within the range 0 to 0x10FFFF, excluding
766        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
767        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
768        does: it's just the validity check that is more restrictive.
769    
770    16. Inserted checks for integer overflows during escape sequence (backslash)
771        processing, and also fixed erroneous offset values for syntax errors during
772        backslash processing.
773    
774    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
775        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
776    
777    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
778        caused an overrun.
779    
780    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
781        something other than just ASCII characters) inside a group that had an
782        unlimited repeat caused a loop at compile time (while checking to see
783        whether the group could match an empty string).
784    
785    20. Debugging a pattern containing \p or \P could cause a crash. For example,
786        [\P{Any}] did so. (Error in the code for printing property names.)
787    
788    21. An orphan \E inside a character class could cause a crash.
789    
790    22. A repeated capturing bracket such as (A)? could cause a wild memory
791        reference during compilation.
792    
793    23. There are several functions in pcre_compile() that scan along a compiled
794        expression for various reasons (e.g. to see if it's fixed length for look
795        behind). There were bugs in these functions when a repeated \p or \P was
796        present in the pattern. These operators have additional parameters compared
797        with \d, etc, and these were not being taken into account when moving along
798        the compiled data. Specifically:
799    
800        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
801            length.
802    
803        (b) An item such as \pL+ within a repeated group could cause crashes or
804            loops.
805    
806        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
807            "reference to non-existent subpattern" error.
808    
809        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
810    
811    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
812        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
813    
814    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
815    
816    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
817        character were causing crashes (broken optimization).
818    
819    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
820        \p or \P) caused a compile-time loop.
821    
822    28. More problems have arisen in unanchored patterns when CRLF is a valid line
823        break. For example, the unstudied pattern [\r\n]A does not match the string
824        "\r\nA" because change 7.0/46 below moves the current point on by two
825        characters after failing to match at the start. However, the pattern \nA
826        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
827        the same is true. There doesn't seem any very clean way out of this, but
828        what I have chosen to do makes the common cases work: PCRE now takes note
829        of whether there can be an explicit match for \r or \n anywhere in the
830        pattern, and if so, 7.0/46 no longer applies. As part of this change,
831        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
832        pattern has explicit CR or LF references.
833    
834    29. Added (*CR) etc for changing newline setting at start of pattern.
835    
836    
837    Version 7.2 19-Jun-07
838    ---------------------
839    
840     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
841        which is apparently normally available under Windows.
842    
843     2. Re-jig the pcregrep tests with different newline settings in an attempt
844        to make them independent of the local environment's newline setting.
845    
846     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
847    
848     4. Some of the "internals" tests were previously cut out when the link size
849        was not 2, because the output contained actual offsets. The recent new
850        "Z" feature of pcretest means that these can be cut out, making the tests
851        usable with all link sizes.
852    
853     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
854        stack recursion. This gives a massive performance boost under BSD, but just
855        a small improvement under Linux. However, it saves one field in the frame
856        in all cases.
857    
858     6. Added more features from the forthcoming Perl 5.10:
859    
860        (a) (?-n) (where n is a string of digits) is a relative subroutine or
861            recursion call. It refers to the nth most recently opened parentheses.
862    
863        (b) (?+n) is also a relative subroutine call; it refers to the nth next
864            to be opened parentheses.
865    
866        (c) Conditions that refer to capturing parentheses can be specified
867            relatively, for example, (?(-2)... or (?(+3)...
868    
869        (d) \K resets the start of the current match so that everything before
870            is not part of it.
871    
872        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
873    
874        (f) \g{name} is another synonym - part of Perl 5.10's unification of
875            reference syntax.
876    
877        (g) (?| introduces a group in which the numbering of parentheses in each
878            alternative starts with the same number.
879    
880        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
881    
882     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
883        PCRE_INFO_JCHANGED.
884    
885     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
886        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
887        for detecting groups that can match an empty string.
888    
889     9. A pattern with a very large number of alternatives (more than several
890        hundred) was running out of internal workspace during the pre-compile
891        phase, where pcre_compile() figures out how much memory will be needed. A
892        bit of new cunning has reduced the workspace needed for groups with
893        alternatives. The 1000-alternative test pattern now uses 12 bytes of
894        workspace instead of running out of the 4096 that are available.
895    
896    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
897    
898    11. Applied patch from Google to remove an optimization that didn't quite work.
899        The report of the bug said:
900    
901          pcrecpp::RE("a*").FullMatch("aaa") matches, while
902          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
903          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
904    
905    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
906        it matched the wrong number of bytes.
907    
908    
909    Version 7.1 24-Apr-07
910    ---------------------
911    
912     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
913        that is more "standard", making use of automake and other Autotools. There
914        is some re-arrangement of the files and adjustment of comments consequent
915        on this.
916    
917     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
918        for recursive directory scanning broke on some systems because the files
919        are not scanned in any specific order and on different systems the order
920        was different. A call to "sort" has been inserted into RunGrepTest for the
921        approprate test as a short-term fix. In the longer term there may be an
922        alternative.
923    
924     3. I had an email from Eric Raymond about problems translating some of PCRE's
925        man pages to HTML (despite the fact that I distribute HTML pages, some
926        people do their own conversions for various reasons). The problems
927        concerned the use of low-level troff macros .br and .in. I have therefore
928        removed all such uses from the man pages (some were redundant, some could
929        be replaced by .nf/.fi pairs). The 132html script that I use to generate
930        HTML has been updated to handle .nf/.fi and to complain if it encounters
931        .br or .in.
932    
933     4. Updated comments in configure.ac that get placed in config.h.in and also
934        arranged for config.h to be included in the distribution, with the name
935        config.h.generic, for the benefit of those who have to compile without
936        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
937    
938     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
939        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
940        makevp.bat for the current PCRE, using the additional files
941        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
942    
943     6. A Windows user reported a minor discrepancy with test 2, which turned out
944        to be caused by a trailing space on an input line that had got lost in his
945        copy. The trailing space was an accident, so I've just removed it.
946    
947     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
948        that is needed.
949    
950     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
951        as "const" (a) because they are and (b) because it helps the PHP
952        maintainers who have recently made a script to detect big data structures
953        in the php code that should be moved to the .rodata section. I remembered
954        to update Builducptable as well, so it won't revert if ucptable.h is ever
955        re-created.
956    
957     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
958        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
959        order to be able to cut out the UTF-8 tables in the latter when UTF-8
960        support is not required. This saves 1.5-2K of code, which is important in
961        some applications.
962    
963        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
964        so as not to refer to the tables, even though these functions will never be
965        called when UTF-8 support is disabled. Otherwise there are problems with a
966        shared library.
967    
968    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
969    
970        (a) It was defining its arguments as char * instead of void *.
971    
972        (b) It was assuming that all moves were upwards in memory; this was true
973            a long time ago when I wrote it, but is no longer the case.
974    
975        The emulated memove() is provided for those environments that have neither
976        memmove() nor bcopy(). I didn't think anyone used it these days, but that
977        is clearly not the case, as these two bugs were recently reported.
978    
979    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
980        and Detrail to create the HTML documentation, the .txt form of the man
981        pages, and it removes trailing spaces from listed files. It also creates
982        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
983        case, it wraps all the #defines with #ifndefs. This script should be run
984        before "make dist".
985    
986    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
987        with Unicode property support.
988    
989        (a) For a maximizing quantifier, if the two different cases of the
990            character were of different lengths in their UTF-8 codings (there are
991            some cases like this - I found 11), and the matching function had to
992            back up over a mixture of the two cases, it incorrectly assumed they
993            were both the same length.
994    
995        (b) When PCRE was configured to use the heap rather than the stack for
996            recursion during matching, it was not correctly preserving the data for
997            the other case of a UTF-8 character when checking ahead for a match
998            while processing a minimizing repeat. If the check also involved
999            matching a wide character, but failed, corruption could cause an
1000            erroneous result when trying to check for a repeat of the original
1001            character.
1002    
1003    13. Some tidying changes to the testing mechanism:
1004    
1005        (a) The RunTest script now detects the internal link size and whether there
1006            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1007            values substituted by "configure". (The RunGrepTest script already did
1008            this for UTF-8.) The configure.ac script no longer substitutes the
1009            relevant variables.
1010    
1011        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1012            with length and offset values. This means that the output is different
1013            for different internal link sizes. Test 2 is skipped for link sizes
1014            other than 2 because of this, bypassing the problem. Unfortunately,
1015            there was also a test in test 3 (the locale tests) that used /B and
1016            failed for link sizes other than 2. Rather than cut the whole test out,
1017            I have added a new /Z option to pcretest that replaces the length and
1018            offset values with spaces. This is now used to make test 3 independent
1019            of link size. (Test 2 will be tidied up later.)
1020    
1021    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1022        segmentation fault instead of returning the appropriate error message.
1023    
1024    15. In multiline mode when the newline sequence was set to "any", the pattern
1025        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1026        This doesn't seem right; it now treats the CRLF combination as the line
1027        ending, and so does not match in that case. It's only a pattern such as ^$
1028        that would hit this one: something like ^ABC$ would have failed after \r
1029        and then tried again after \r\n.
1030    
1031    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1032        in an attempt to make files that differ only in their line terminators
1033        compare equal. This works on Linux.
1034    
1035    17. Under certain error circumstances pcregrep might try to free random memory
1036        as it exited. This is now fixed, thanks to valgrind.
1037    
1038    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1039        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1040        was because its rules for how to advance for /g after matching an empty
1041        string at the end of a line did not allow for this case. They now check for
1042        it specially.
1043    
1044    20. pcretest is supposed to handle patterns and data of any length, by
1045        extending its buffers when necessary. It was getting this wrong when the
1046        buffer for a data line had to be extended.
1047    
1048    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1049        CRLF as a newline sequence.
1050    
1051    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1052        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1053        I have nevertheless tidied it up.
1054    
1055    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1056    
1057    24. Added a man page for pcre-config.
1058    
1059    
1060    Version 7.0 19-Dec-06
1061    ---------------------
1062    
1063     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1064        moving to gcc 4.1.1.
1065    
1066     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1067        sys/time.h, which is documented as needed for this function. It doesn't
1068        seem to matter on Linux, but it showed up on some releases of OS X.
1069    
1070     3. It seems that there are systems where bytes whose values are greater than
1071        127 match isprint() in the "C" locale. The "C" locale should be the
1072        default when a C program starts up. In most systems, only ASCII printing
1073        characters match isprint(). This difference caused the output from pcretest
1074        to vary, making some of the tests fail. I have changed pcretest so that:
1075    
1076        (a) When it is outputting text in the compiled version of a pattern, bytes
1077            other than 32-126 are always shown as hex escapes.
1078    
1079        (b) When it is outputting text that is a matched part of a subject string,
1080            it does the same, unless a different locale has been set for the match
1081            (using the /L modifier). In this case, it uses isprint() to decide.
1082    
1083     4. Fixed a major bug that caused incorrect computation of the amount of memory
1084        required for a compiled pattern when options that changed within the
1085        pattern affected the logic of the preliminary scan that determines the
1086        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1087        that the computed length was too small. The symptoms of this bug were
1088        either the PCRE error "internal error: code overflow" from pcre_compile(),
1089        or a glibc crash with a message such as "pcretest: free(): invalid next
1090        size (fast)". Examples of patterns that provoked this bug (shown in
1091        pcretest format) are:
1092    
1093          /(?-x: )/x
1094          /(?x)(?-x: \s*#\s*)/
1095          /((?i)[\x{c0}])/8
1096          /(?i:[\x{c0}])/8
1097    
1098        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1099        is now done differently.
1100    
1101     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1102        wrapper classes; (b) implement a new function in the C++ scanner that is
1103        more efficient than the old way of doing things because it avoids levels of
1104        recursion in the regex matching; (c) add a paragraph to the documentation
1105        for the FullMatch() function.
1106    
1107     6. The escape sequence \n was being treated as whatever was defined as
1108        "newline". Not only was this contrary to the documentation, which states
1109        that \n is character 10 (hex 0A), but it also went horribly wrong when
1110        "newline" was defined as CRLF. This has been fixed.
1111    
1112     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1113        was being set to -1 for the "end of line" case (supposedly a value that no
1114        character can have). Though this value is never used (the check for end of
1115        line is "zero bytes in current character"), it caused compiler complaints.
1116        I've changed it to 0xffffffff.
1117    
1118     8. In pcre_version.c, the version string was being built by a sequence of
1119        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1120        string (as it is for production releases) called a macro with an empty
1121        argument. The C standard says the result of this is undefined. The gcc
1122        compiler treats it as an empty string (which was what was wanted) but it is
1123        reported that Visual C gives an error. The source has been hacked around to
1124        avoid this problem.
1125    
1126     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1127        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1128        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1129        of them did).
1130    
1131    10. Originally, pcretest opened its input and output without "b"; then I was
1132        told that "b" was needed in some environments, so it was added for release
1133        5.0 to both the input and output. (It makes no difference on Unix-like
1134        systems.) Later I was told that it is wrong for the input on Windows. I've
1135        now abstracted the modes into two macros, to make it easier to fiddle with
1136        them, and removed "b" from the input mode under Windows.
1137    
1138    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1139    
1140    12. Added -help and --help to pcretest as an official way of being reminded
1141        of the options.
1142    
1143    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1144        and pcrecpp.cc because they annoy compilers at high warning levels.
1145    
1146    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1147    
1148    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1149        scripts are not C programs :-) and which was not noticed because it works
1150        on Linux.
1151    
1152    16. pcretest is supposed to handle any length of pattern and data line (as one
1153        line or as a continued sequence of lines) by extending its input buffer if
1154        necessary. This feature was broken for very long pattern lines, leading to
1155        a string of junk being passed to pcre_compile() if the pattern was longer
1156        than about 50K.
1157    
1158    17. I have done a major re-factoring of the way pcre_compile() computes the
1159        amount of memory needed for a compiled pattern. Previously, there was code
1160        that made a preliminary scan of the pattern in order to do this. That was
1161        OK when PCRE was new, but as the facilities have expanded, it has become
1162        harder and harder to keep it in step with the real compile phase, and there
1163        have been a number of bugs (see for example, 4 above). I have now found a
1164        cunning way of running the real compile function in a "fake" mode that
1165        enables it to compute how much memory it would need, while actually only
1166        ever using a few hundred bytes of working memory and without too many
1167        tests of the mode. This should make future maintenance and development
1168        easier. A side effect of this work is that the limit of 200 on the nesting
1169        depth of parentheses has been removed (though this was never a serious
1170        limitation, I suspect). However, there is a downside: pcre_compile() now
1171        runs more slowly than before (30% or more, depending on the pattern). I
1172        hope this isn't a big issue. There is no effect on runtime performance.
1173    
1174    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1175        newline (only possible for the last line of a file) and it was a
1176        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1177    
1178    19. Added additional timing features to pcretest. (1) The -tm option now times
1179        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1180        separate command line item, by a number that specifies the number of
1181        repeats to use when timing. The default is 50000; this gives better
1182        precision, but takes uncomfortably long for very large patterns.
1183    
1184    20. Extended pcre_study() to be more clever in cases where a branch of a
1185        subpattern has no definite first character. For example, (a*|b*)[cd] would
1186        previously give no result from pcre_study(). Now it recognizes that the
1187        first character must be a, b, c, or d.
1188    
1189    21. There was an incorrect error "recursive call could loop indefinitely" if
1190        a subpattern (or the entire pattern) that was being tested for matching an
1191        empty string contained only one non-empty item after a nested subpattern.
1192        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1193        incorrectly, because the \d was being skipped in the check.
1194    
1195    22. The pcretest program now has a new pattern option /B and a command line
1196        option -b, which is equivalent to adding /B to every pattern. This causes
1197        it to show the compiled bytecode, without the additional information that
1198        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1199        is the same as /B/I).
1200    
1201    23. A new optimization is now able automatically to treat some sequences such
1202        as a*b as a*+b. More specifically, if something simple (such as a character
1203        or a simple class like \d) has an unlimited quantifier, and is followed by
1204        something that cannot possibly match the quantified thing, the quantifier
1205        is automatically "possessified".
1206    
1207    24. A recursive reference to a subpattern whose number was greater than 39
1208        went wrong under certain circumstances in UTF-8 mode. This bug could also
1209        have affected the operation of pcre_study().
1210    
1211    25. Realized that a little bit of performance could be had by replacing
1212        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1213    
1214    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1215    
1216    27. Possessive quantifiers such as a++ were previously implemented by turning
1217        them into atomic groups such as ($>a+). Now they have their own opcodes,
1218        which improves performance. This includes the automatically created ones
1219        from 23 above.
1220    
1221    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1222        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1223        the first matched character to be a colon. This applied both to named and
1224        numbered groups.
1225    
1226    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1227    
1228    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1229        building PCRE on Windows easier, so I have included it in the distribution.
1230    
1231    31. There is now a check in pcretest against a ridiculously large number being
1232        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1233        loop, the loop is abandoned.
1234    
1235    32. Forward references to subpatterns in conditions such as (?(2)...) where
1236        subpattern 2 is defined later cause pcre_compile() to search forwards in
1237        the pattern for the relevant set of parentheses. This search went wrong
1238        when there were unescaped parentheses in a character class, parentheses
1239        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1240    
1241    33. "Subroutine" calls and backreferences were previously restricted to
1242        referencing subpatterns earlier in the regex. This restriction has now
1243        been removed.
1244    
1245    34. Added a number of extra features that are going to be in Perl 5.10. On the
1246        whole, these are just syntactic alternatives for features that PCRE had
1247        previously implemented using the Python syntax or my own invention. The
1248        other formats are all retained for compatibility.
1249    
1250        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1251            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1252            also .NET compatible.
1253    
1254        (b) A recursion or subroutine call to a named group can now be defined as
1255            (?&name) as well as (?P>name).
1256    
1257        (c) A backreference to a named group can now be defined as \k<name> or
1258            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1259            5.10, are also .NET compatible.
1260    
1261        (d) A conditional reference to a named group can now use the syntax
1262            (?(<name>) or (?('name') as well as (?(name).
1263    
1264        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1265            groups (named and numbered) that are never evaluated inline, but can be
1266            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1267            is always false. There may be only one alternative in such a group.
1268    
1269        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1270            as the simple (?(R). The condition is true only if the most recent
1271            recursion is that of the given number or name. It does not search out
1272            through the entire recursion stack.
1273    
1274        (g) The escape \gN or \g{N} has been added, where N is a positive or
1275            negative number, specifying an absolute or relative reference.
1276    
1277    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1278        some "unreachable code" warnings.
1279    
1280    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1281        things, this adds five new scripts.
1282    
1283    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1284        There were also incompatibilities regarding the handling of \Q..\E inside
1285        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1286        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1287    
1288    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1289        matches an empty string, and forcibly breaks the loop. There were bugs in
1290        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1291        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1292        separate and independent bugs (that affected different cases) have been
1293        fixed.
1294    
1295    39. Refactored the code to abolish the use of different opcodes for small
1296        capturing bracket numbers. This is a tidy that I avoided doing when I
1297        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1298        The new approach is not only tidier, it makes it possible to reduce the
1299        memory needed to fix the previous bug (38).
1300    
1301    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1302        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1303        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1304        mode.
1305    
1306    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1307        report.
1308    
1309    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1310        copy construction and assignment in the C++ wrapper.
1311    
1312    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1313        couple of bugs that could have given wrong results in the "--newline=crlf"
1314        case.
1315    
1316    44. Added a number of casts and did some reorganization of signed/unsigned int
1317        variables following suggestions from Dair Grant. Also renamed the variable
1318        "this" as "item" because it is a C++ keyword.
1319    
1320    45. Arranged for dftables to add
1321    
1322          #include "pcre_internal.h"
1323    
1324        to pcre_chartables.c because without it, gcc 4.x may remove the array
1325        definition from the final binary if PCRE is built into a static library and
1326        dead code stripping is activated.
1327    
1328    46. For an unanchored pattern, if a match attempt fails at the start of a
1329        newline sequence, and the newline setting is CRLF or ANY, and the next two
1330        characters are CRLF, advance by two characters instead of one.
1331    
1332    
1333    Version 6.7 04-Jul-06
1334    ---------------------
1335    
1336     1. In order to handle tests when input lines are enormously long, pcretest has
1337        been re-factored so that it automatically extends its buffers when
1338        necessary. The code is crude, but this _is_ just a test program. The
1339        default size has been increased from 32K to 50K.
1340    
1341     2. The code in pcre_study() was using the value of the re argument before
1342        testing it for NULL. (Of course, in any sensible call of the function, it
1343        won't be NULL.)
1344    
1345     3. The memmove() emulation function in pcre_internal.h, which is used on
1346        systems that lack both memmove() and bcopy() - that is, hardly ever -
1347        was missing a "static" storage class specifier.
1348    
1349     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1350        containing an extended class (one that cannot be represented by a bitmap
1351        because it contains high-valued characters or Unicode property items, e.g.
1352        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1353        pattern, but PCRE should not loop if you do not (it no longer does).
1354        [Detail: two cases were found: (a) a repeated subpattern containing an
1355        extended class; (b) a recursive reference to a subpattern that followed a
1356        previous extended class. It wasn't skipping over the extended class
1357        correctly when UTF-8 mode was not set.]
1358    
1359     5. A negated single-character class was not being recognized as fixed-length
1360        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1361        compile error "lookbehind assertion is not fixed length".
1362    
1363     6. The RunPerlTest auxiliary script was showing an unexpected difference
1364        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1365        write a Perl script that can interpret lines of an input file either as
1366        byte characters or as UTF-8, which is what "perltest" was being required to
1367        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1368        can't do is switch easily at run time between having the "use utf8;" pragma
1369        or not. In the end, I fudged it by using the RunPerlTest script to insert
1370        "use utf8;" explicitly for the UTF-8 tests.
1371    
1372     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1373        the end of the subject string, contrary to the documentation and to what
1374        Perl does. This was true of both matching functions. Now it matches only at
1375        the start of the subject and immediately after *internal* newlines.
1376    
1377     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1378        a pointer to an int instead of a pointer to an unsigned long int. This
1379        caused problems on 64-bit systems.
1380    
1381     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1382        instance of the 'standard' template library not being so standard".
1383    
1384    10. There was no check on the number of named subpatterns nor the maximum
1385        length of a subpattern name. The product of these values is used to compute
1386        the size of the memory block for a compiled pattern. By supplying a very
1387        long subpattern name and a large number of named subpatterns, the size
1388        computation could be caused to overflow. This is now prevented by limiting
1389        the length of names to 32 characters, and the number of named subpatterns
1390        to 10,000.
1391    
1392    11. Subpatterns that are repeated with specific counts have to be replicated in
1393        the compiled pattern. The size of memory for this was computed from the
1394        length of the subpattern and the repeat count. The latter is limited to
1395        65535, but there was no limit on the former, meaning that integer overflow
1396        could in principle occur. The compiled length of a repeated subpattern is
1397        now limited to 30,000 bytes in order to prevent this.
1398    
1399    12. Added the optional facility to have named substrings with the same name.
1400    
1401    13. Added the ability to use a named substring as a condition, using the
1402        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1403        are numbers (not recommended). Forward references are permitted.
1404    
1405    14. Added forward references in named backreferences (if you see what I mean).
1406    
1407    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1408        pattern could run off the end of the subject. For example, the pattern
1409        "(?s)(.{1,5})"8 did this with the subject "ab".
1410    
1411    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1412        PCRE_CASELESS was set when matching characters that were quantified with ?
1413        or *.
1414    
1415    17. A character class other than a single negated character that had a minimum
1416        but no maximum quantifier - for example [ab]{6,} - was not handled
1417        correctly by pce_dfa_exec(). It would match only one character.
1418    
1419    18. A valid (though odd) pattern that looked like a POSIX character
1420        class but used an invalid character after [ (for example [[,abc,]]) caused
1421        pcre_compile() to give the error "Failed: internal error: code overflow" or
1422        in some cases to crash with a glibc free() error. This could even happen if
1423        the pattern terminated after [[ but there just happened to be a sequence of
1424        letters, a binary zero, and a closing ] in the memory that followed.
1425    
1426    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1427        over the years. Originally (before any Unicode support), just the bottom 8
1428        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1429        output from "man perlunicode" includes this:
1430    
1431          The regular expression compiler produces polymorphic opcodes.  That
1432          is, the pattern adapts to the data and automatically switches to
1433          the Unicode character scheme when presented with Unicode data--or
1434          instead uses a traditional byte scheme when presented with byte
1435          data.
1436    
1437        Sadly, a wide octal escape does not cause a switch, and in a string with
1438        no other multibyte characters, these octal escapes are treated as before.
1439        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1440        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1441        Unicode string.
1442    
1443        I have not perpetrated such confusion in PCRE. Up till now, it took just
1444        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1445        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1446        translate to the appropriate multibyte character.
1447    
1448    29. Applied some refactoring to reduce the number of warnings from Microsoft
1449        and Borland compilers. This has included removing the fudge introduced
1450        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1451        a warning about an unused variable.
1452    
1453    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1454        characters since release 4.0, because Perl (from release 5.004) does not.
1455        [Or at least, is documented not to: some releases seem to be in conflict
1456        with the documentation.] However, when a pattern was studied with
1457        pcre_study() and all its branches started with \s, PCRE still included VT
1458        as a possible starting character. Of course, this did no harm; it just
1459        caused an unnecessary match attempt.
1460    
1461    22. Removed a now-redundant internal flag bit that recorded the fact that case
1462        dependency changed within the pattern. This was once needed for "required
1463        byte" processing, but is no longer used. This recovers a now-scarce options
1464        bit. Also moved the least significant internal flag bit to the most-
1465        significant bit of the word, which was not previously used (hangover from
1466        the days when it was an int rather than a uint) to free up another bit for
1467        the future.
1468    
1469    23. Added support for CRLF line endings as well as CR and LF. As well as the
1470        default being selectable at build time, it can now be changed at runtime
1471        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1472        specify that it is scanning data with non-default line endings.
1473    
1474    24. Changed the definition of CXXLINK to make it agree with the definition of
1475        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1476    
1477    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1478        recursions. This makes a big different to stack usage for some patterns.
1479    
1480    26. If a subpattern containing a named recursion or subroutine reference such
1481        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1482        the space required for the compiled pattern went wrong and gave too small a
1483        value. Depending on the environment, this could lead to "Failed: internal
1484        error: code overflow at offset 49" or "glibc detected double free or
1485        corruption" errors.
1486    
1487    27. Applied patches from Google (a) to support the new newline modes and (b) to
1488        advance over multibyte UTF-8 characters in GlobalReplace.
1489    
1490    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1491        difference for some implementation of PCRE in some Windows version.
1492    
1493    29. Added some extra testing facilities to pcretest:
1494    
1495        \q<number>   in a data line sets the "match limit" value
1496        \Q<number>   in a data line sets the "match recursion limt" value
1497        -S <number>  sets the stack size, where <number> is in megabytes
1498    
1499        The -S option isn't available for Windows.
1500    
1501    
1502    Version 6.6 06-Feb-06
1503    ---------------------
1504    
1505     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1506        in pcreposix.h. I have copied the definition from pcre.h.
1507    
1508     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1509        because pcre.h is no longer a built file.
1510    
1511     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1512        not normally included in the compiled code.
1513    
1514    
1515    Version 6.5 01-Feb-06
1516    ---------------------
1517    
1518     1. When using the partial match feature with pcre_dfa_exec(), it was not
1519        anchoring the second and subsequent partial matches at the new starting
1520        point. This could lead to incorrect results. For example, with the pattern
1521        /1234/, partially matching against "123" and then "a4" gave a match.
1522    
1523     2. Changes to pcregrep:
1524    
1525        (a) All non-match returns from pcre_exec() were being treated as failures
1526            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1527            error message is output. Some extra information is given for the
1528            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1529            probably the only errors that are likely to be caused by users (by
1530            specifying a regex that has nested indefinite repeats, for instance).
1531            If there are more than 20 of these errors, pcregrep is abandoned.
1532    
1533        (b) A binary zero was treated as data while matching, but terminated the
1534            output line if it was written out. This has been fixed: binary zeroes
1535            are now no different to any other data bytes.
1536    
1537        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1538            used to set a locale for matching. The --locale=xxxx long option has
1539            been added (no short equivalent) to specify a locale explicitly on the
1540            pcregrep command, overriding the environment variables.
1541    
1542        (d) When -B was used with -n, some line numbers in the output were one less
1543            than they should have been.
1544    
1545        (e) Added the -o (--only-matching) option.
1546    
1547        (f) If -A or -C was used with -c (count only), some lines of context were
1548            accidentally printed for the final match.
1549    
1550        (g) Added the -H (--with-filename) option.
1551    
1552        (h) The combination of options -rh failed to suppress file names for files
1553            that were found from directory arguments.
1554    
1555        (i) Added the -D (--devices) and -d (--directories) options.
1556    
1557        (j) Added the -F (--fixed-strings) option.
1558    
1559        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1560    
1561        (l) Added the --colo(u)r option.
1562    
1563        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1564            is not present by default.
1565    
1566     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1567        items such as (?R) or (?1), when the recursion could match a number of
1568        alternatives. If it matched one of the alternatives, but subsequently,
1569        outside the recursion, there was a failure, the code tried to back up into
1570        the recursion. However, because of the way PCRE is implemented, this is not
1571        possible, and the result was an incorrect result from the match.
1572    
1573        In order to prevent this happening, the specification of recursion has
1574        been changed so that all such subpatterns are automatically treated as
1575        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1576    
1577     4. I had overlooked the fact that, in some locales, there are characters for
1578        which isalpha() is true but neither isupper() nor islower() are true. In
1579        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1580        and ordfeminine) are like this. This affected the treatment of \w and \W
1581        when they appeared in character classes, but not when they appeared outside
1582        a character class. The bit map for "word" characters is now created
1583        separately from the results of isalnum() instead of just taking it from the
1584        upper, lower, and digit maps. (Plus the underscore character, of course.)
1585    
1586     5. The above bug also affected the handling of POSIX character classes such as
1587        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1588        permanent tables. Instead, the bit maps for such a class were previously
1589        created as the appropriate unions of the upper, lower, and digit bitmaps.
1590        Now they are created by subtraction from the [[:word:]] class, which has
1591        its own bitmap.
1592    
1593     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1594        It is created by subtracting the vertical space characters (\x09, \x0a,
1595        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1596        subtraction was done in the overall bitmap for a character class, meaning
1597        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1598        be recognized. This bug has been fixed.
1599    
1600     7. Patches from the folks at Google:
1601    
1602          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1603          real life, but is still worth protecting against".
1604    
1605          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1606          regular expressions".
1607    
1608          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1609          have it.
1610    
1611          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1612          "configure" and the latter not, in order to fix a problem somebody had
1613          with compiling the Arg class on HP-UX.
1614    
1615          (e) Improve the error-handling of the C++ wrapper a little bit.
1616    
1617          (f) New tests for checking recursion limiting.
1618    
1619     8. The pcre_memmove() function, which is used only if the environment does not
1620        have a standard memmove() function (and is therefore rarely compiled),
1621        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1622        returning a result (though PCRE never actually uses the result).
1623    
1624     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1625        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1626        returned instead of calling malloc() with an overflowing number that would
1627        most likely cause subsequent chaos.
1628    
1629    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1630    
1631    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1632        with this option is matched, the nmatch and pmatch options of regexec() are
1633        ignored.
1634    
1635    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1636        provided in case anyone wants to the the POSIX interface with UTF-8
1637        strings.
1638    
1639    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1640        C++ linking (needed for some HP-UX environments).
1641    
1642    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1643        (unused parameter) and in the pcre_printint() function (omitted "default"
1644        switch label when the default is to do nothing).
1645    
1646    15. Added some code to make it possible, when PCRE is compiled as a C++
1647        library, to replace subject pointers for pcre_exec() with a smart pointer
1648        class, thus making it possible to process discontinuous strings.
1649    
1650    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1651        much the same function. They were added by different people who were trying
1652        to make PCRE easy to compile on non-Unix systems. It has been suggested
1653        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1654        for compiling on Windows systems. I have therefore replaced it with
1655        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1656        defaults to "extern" for C or "extern C" for C++, which works fine on
1657        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1658        SCOPE with something explicit in config.h. In addition:
1659    
1660        (a) pcreposix.h still had just "extern" instead of either of these macros;
1661            I have replaced it with PCRE_DATA_SCOPE.
1662    
1663        (b) Functions such as _pcre_xclass(), which are internal to the library,
1664            but external in the C sense, all had PCRE_EXPORT in their definitions.
1665            This is apparently wrong for the Windows case, so I have removed it.
1666            (It makes no difference on Unix-like systems.)
1667    
1668    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1669        of recursive calls to match(). This is different to MATCH_LIMIT because
1670        that limits the total number of calls to match(), not all of which increase
1671        the depth of recursion. Limiting the recursion depth limits the amount of
1672        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1673        when PCRE is compiled, and changed at run time. A patch from Google adds
1674        this functionality to the C++ interface.
1675    
1676    18. Changes to the handling of Unicode character properties:
1677    
1678        (a) Updated the table to Unicode 4.1.0.
1679    
1680        (b) Recognize characters that are not in the table as "Cn" (undefined).
1681    
1682        (c) I revised the way the table is implemented to a much improved format
1683            which includes recognition of ranges. It now supports the ranges that
1684            are defined in UnicodeData.txt, and it also amalgamates other
1685            characters into ranges. This has reduced the number of entries in the
1686            table from around 16,000 to around 3,000, thus reducing its size
1687            considerably. I realized I did not need to use a tree structure after
1688            all - a binary chop search is just as efficient. Having reduced the
1689            number of entries, I extended their size from 6 bytes to 8 bytes to
1690            allow for more data.
1691    
1692        (d) Added support for Unicode script names via properties such as \p{Han}.
1693    
1694    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1695        matching that character.
1696    
1697    20. When matching a repeated Unicode property with a minimum greater than zero,
1698        (for example \pL{2,}), PCRE could look past the end of the subject if it
1699        reached it while seeking the minimum number of characters. This could
1700        happen only if some of the characters were more than one byte long, because
1701        there is a check for at least the minimum number of bytes.
1702    
1703    21. Refactored the implementation of \p and \P so as to be more general, to
1704        allow for more different types of property in future. This has changed the
1705        compiled form incompatibly. Anybody with saved compiled patterns that use
1706        \p or \P will have to recompile them.
1707    
1708    22. Added "Any" and "L&" to the supported property types.
1709    
1710    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1711        but give a compile time error if the value is greater than 0xff.
1712    
1713    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1714        accidentally not being installed or uninstalled.
1715    
1716    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1717        made were to insert the current release number. This seemed silly, because
1718        it made things harder for people building PCRE on systems that don't run
1719        "configure". I have turned pcre.h into a distributed file, no longer built
1720        by "configure", with the version identification directly included. There is
1721        no longer a pcre.h.in file.
1722    
1723        However, this change necessitated a change to the pcre-config script as
1724        well. It is built from pcre-config.in, and one of the substitutions was the
1725        release number. I have updated configure.ac so that ./configure now finds
1726        the release number by grepping pcre.h.
1727    
1728    26. Added the ability to run the tests under valgrind.
1729    
1730    
1731    Version 6.4 05-Sep-05
1732    ---------------------
1733    
1734     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1735        "--" to be printed when multiple files were scanned, even when none of the
1736        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1737        consider it to be a bug, and have restored the previous behaviour.
1738    
1739     2. A couple of code tidies to get rid of compiler warnings.
1740    
1741     3. The pcretest program used to cheat by referring to symbols in the library
1742        whose names begin with _pcre_. These are internal symbols that are not
1743        really supposed to be visible externally, and in some environments it is
1744        possible to suppress them. The cheating is now confined to including
1745        certain files from the library's source, which is a bit cleaner.
1746    
1747     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1748        file's purpose clearer.
1749    
1750     5. Reorganized pcre_ucp_findchar().
1751    
1752    
1753    Version 6.3 15-Aug-05
1754    ---------------------
1755    
1756     1. The file libpcre.pc.in did not have general read permission in the tarball.
1757    
1758     2. There were some problems when building without C++ support:
1759    
1760        (a) If C++ support was not built, "make install" and "make test" still
1761            tried to test it.
1762    
1763        (b) There were problems when the value of CXX was explicitly set. Some
1764            changes have been made to try to fix these, and ...
1765    
1766        (c) --disable-cpp can now be used to explicitly disable C++ support.
1767    
1768        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1769            backslash in a target when C++ was disabled. This confuses some
1770            versions of "make", apparently. Using an intermediate variable solves
1771            this. (Same for CPP_LOBJ.)
1772    
1773     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1774        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1775        necessary on certain architectures.
1776    
1777     4. Added a setting of -export-symbols-regex to the link command to remove
1778        those symbols that are exported in the C sense, but actually are local
1779        within the library, and not documented. Their names all begin with
1780        "_pcre_". This is not a perfect job, because (a) we have to except some
1781        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1782        available (and never for static libraries). I have made a note to try to
1783        find a way round (a) in the future.
1784    
1785    
1786  Version 6.2 01-Aug-05  Version 6.2 01-Aug-05
1787  ---------------------  ---------------------
1788    

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