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revision 65 by nigel, Sat Feb 24 21:40:08 2007 UTC revision 446 by ph10, Tue Sep 15 10:49:50 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8        was out-of-date, and there was no check on the pcre_compile() error code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 nmatch with a NULL value for pmatch, the value of
101        nmatch is forced to zero.
102    
103    18. RunGrepTest did not have a test for the availability of the -u option of
104        the diff command, as RunTest does. It now checks in the same way as
105        RunTest, and also checks for the -b option.
106    
107    19. If an odd number of negated classes containing just a single character
108        interposed, within parentheses, between a forward reference to a named
109        subpattern and the definition of the subpattern, compilation crashed with
110        an internal error, complaining that it could not find the referenced
111        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
112        [The bug was that it was starting one character too far in when skipping
113        over the character class, thus treating the ] as data rather than
114        terminating the class. This meant it could skip too much.]
115    
116    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
117        /g option in pcretest when the pattern contains \K, which makes it possible
118        to have an empty string match not at the start, even when the pattern is
119        anchored. Updated pcretest and pcredemo to use this option.
120    
121    21. If the maximum number of capturing subpatterns in a recursion was greater
122        than the maximum at the outer level, the higher number was returned, but
123        with unset values at the outer level. The correct (outer level) value is
124        now given.
125    
126    
127    Version 7.9 11-Apr-09
128    ---------------------
129    
130    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
131        (pcretest), all targets were linked against these libraries. This included
132        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
133        libraries. This caused unwanted dependencies to be created. This problem
134        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
135        pcretest is linked with readline.
136    
137    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
138        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
139        moved outside it again, because FALSE and TRUE are already defined in AIX,
140        but BOOL is not.
141    
142    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
143        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
144    
145    4.  The pcregrep documentation said spaces were inserted as well as colons (or
146        hyphens) following file names and line numbers when outputting matching
147        lines. This is not true; no spaces are inserted. I have also clarified the
148        wording for the --colour (or --color) option.
149    
150    5.  In pcregrep, when --colour was used with -o, the list of matching strings
151        was not coloured; this is different to GNU grep, so I have changed it to be
152        the same.
153    
154    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
155        each matching line was coloured. Now it goes on to look for further matches
156        of any of the test patterns, which is the same behaviour as GNU grep.
157    
158    7.  A pattern that could match an empty string could cause pcregrep to loop; it
159        doesn't make sense to accept an empty string match in pcregrep, so I have
160        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
161        seems to be how GNU grep behaves.
162    
163    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
164        start or after a newline", because the conditional assertion was not being
165        correctly handled. The rule now is that both the assertion and what follows
166        in the first alternative must satisfy the test.
167    
168    9.  If auto-callout was enabled in a pattern with a conditional group whose
169        condition was an assertion, PCRE could crash during matching, both with
170        pcre_exec() and pcre_dfa_exec().
171    
172    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
173        used for matching.
174    
175    11. Unicode property support in character classes was not working for
176        characters (bytes) greater than 127 when not in UTF-8 mode.
177    
178    12. Added the -M command line option to pcretest.
179    
180    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
181    
182    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
183    
184    16. Added comments and documentation about mis-use of no_arg in the C++
185        wrapper.
186    
187    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
188        from Martin Jerabek that uses macro names for all relevant character and
189        string constants.
190    
191    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
192        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
193        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
194        these, but not everybody uses configure.
195    
196    19. A conditional group that had only one branch was not being correctly
197        recognized as an item that could match an empty string. This meant that an
198        enclosing group might also not be so recognized, causing infinite looping
199        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
200        with the subject "ab", where knowledge that the repeated group can match
201        nothing is needed in order to break the loop.
202    
203    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
204        exec(), but without supplying a callout function, matching went wrong.
205    
206    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
207        leak if the size of the offset vector was greater than 30. When the vector
208        is smaller, the saved offsets during recursion go onto a local stack
209        vector, but for larger vectors malloc() is used. It was failing to free
210        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
211        error, in fact).
212    
213    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
214        heapframe that is used only when UTF-8 support is enabled. This caused no
215        problem, but was untidy.
216    
217    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
218        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
219        included within another project.
220    
221    24. Steven Van Ingelgem's patches to add more options to the CMake support,
222        slightly modified by me:
223    
224          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
225              not building pcregrep.
226    
227          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
228              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
229    
230    25. Forward references, both numeric and by name, in patterns that made use of
231        duplicate group numbers, could behave incorrectly or give incorrect errors,
232        because when scanning forward to find the reference group, PCRE was not
233        taking into account the duplicate group numbers. A pattern such as
234        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
235    
236    26. Changed a few more instances of "const unsigned char *" to USPTR, making
237        the feature of a custom pointer more persuasive (as requested by a user).
238    
239    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
240        pcretest.c, inside #ifndefs, because it seems they are sometimes already
241        pre-defined.
242    
243    28. Added support for (*UTF8) at the start of a pattern.
244    
245    29. Arrange for flags added by the "release type" setting in CMake to be shown
246        in the configuration summary.
247    
248    
249    Version 7.8 05-Sep-08
250    ---------------------
251    
252    1.  Replaced UCP searching code with optimized version as implemented for Ad
253        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
254        stage table and inline lookup instead of a function, giving speed ups of 2
255        to 5 times on some simple patterns that I tested. Permission was given to
256        distribute the MultiStage2.py script that generates the tables (it's not in
257        the tarball, but is in the Subversion repository).
258    
259    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
260        scripts.
261    
262    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
263        a group with a zero qualifier. The result of the study could be incorrect,
264        or the function might crash, depending on the pattern.
265    
266    4.  Caseless matching was not working for non-ASCII characters in back
267        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
268        It now works when Unicode Property Support is available.
269    
270    5.  In pcretest, an escape such as \x{de} in the data was always generating
271        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
272        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
273        truncation.
274    
275    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
276    
277    7.  Added two (int) casts to pcregrep when printing the difference of two
278        pointers, in case they are 64-bit values.
279    
280    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
281        test 2 if it fails.
282    
283    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
284        and a #define of that name to empty if it is not externally set. This is to
285        allow users of MSVC to set it if necessary.
286    
287    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
288        the convenience functions in the pcre_get.c source file.
289    
290    11. An option change at the start of a pattern that had top-level alternatives
291        could cause overwriting and/or a crash. This command provoked a crash in
292        some environments:
293    
294          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
295    
296        This potential security problem was recorded as CVE-2008-2371.
297    
298    12. For a pattern where the match had to start at the beginning or immediately
299        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
300        pcre_dfa_exec() could read past the end of the passed subject if there was
301        no match. To help with detecting such bugs (e.g. with valgrind), I modified
302        pcretest so that it places the subject at the end of its malloc-ed buffer.
303    
304    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
305        exec() might read past the end of the data buffer in UTF-8 mode.
306    
307    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
308        the data contained the byte 0x85 as part of a UTF-8 character within its
309        first line. This applied both to normal and DFA matching.
310    
311    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
312        /^[^d]*?$/8 failed to match "abc".
313    
314    16. Added a missing copyright notice to pcrecpp_internal.h.
315    
316    17. Make it more clear in the documentation that values returned from
317        pcre_exec() in ovector are byte offsets, not character counts.
318    
319    18. Tidied a few places to stop certain compilers from issuing warnings.
320    
321    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
322        supplied by Stefan Weber. I made a further small update for 7.8 because
323        there is a change of source arrangements: the pcre_searchfuncs.c module is
324        replaced by pcre_ucd.c.
325    
326    
327    Version 7.7 07-May-08
328    ---------------------
329    
330    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
331        a string to a long long, pretend we don't even have a long long." This is
332        done by checking for the strtoq, strtoll, and _strtoi64 functions.
333    
334    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
335        pre-7.6 versions, which defined a global no_arg variable instead of putting
336        it in the RE class. (See also #8 below.)
337    
338    3.  Remove a line of dead code, identified by coverity and reported by Nuno
339        Lopes.
340    
341    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
342    
343        (1) The include/exclude patterns were being applied to the whole pathnames
344            of files, instead of just to the final components.
345    
346        (2) If there was more than one level of directory, the subdirectories were
347            skipped unless they satisfied the include/exclude conditions. This is
348            inconsistent with GNU grep (and could even be seen as contrary to the
349            pcregrep specification - which I improved to make it absolutely clear).
350            The action now is always to scan all levels of directory, and just
351            apply the include/exclude patterns to regular files.
352    
353    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
354        --exclude_dir in the tests to avoid scanning .svn directories.
355    
356    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
357        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
358        doesn't support NULs in patterns.
359    
360    7.  Added some missing "const"s to declarations of static tables in
361        pcre_compile.c and pcre_dfa_exec.c.
362    
363    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
364        caused by fix #2  above. (Subsequently also a second patch to fix the
365        first patch. And a third patch - this was a messy problem.)
366    
367    9.  Applied Craig's patch to remove the use of push_back().
368    
369    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
370        matching function regexec().
371    
372    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
373        which, however, unlike Perl's \g{...}, are subroutine calls, not back
374        references. PCRE supports relative numbers with this syntax (I don't think
375        Oniguruma does).
376    
377    12. Previously, a group with a zero repeat such as (...){0} was completely
378        omitted from the compiled regex. However, this means that if the group
379        was called as a subroutine from elsewhere in the pattern, things went wrong
380        (an internal error was given). Such groups are now left in the compiled
381        pattern, with a new opcode that causes them to be skipped at execution
382        time.
383    
384    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
385        to the way PCRE behaves:
386    
387        (a) A lone ] character is dis-allowed (Perl treats it as data).
388    
389        (b) A back reference to an unmatched subpattern matches an empty string
390            (Perl fails the current match path).
391    
392        (c) A data ] in a character class must be notated as \] because if the
393            first data character in a class is ], it defines an empty class. (In
394            Perl it is not possible to have an empty class.) The empty class []
395            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
396            The negative empty class [^] matches any one character, independently
397            of the DOTALL setting.
398    
399    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
400        non-existent subpattern following a character class starting with ']' and
401        containing () gave an internal compiling error instead of "reference to
402        non-existent subpattern". Fortunately, when the pattern did exist, the
403        compiled code was correct. (When scanning forwards to check for the
404        existencd of the subpattern, it was treating the data ']' as terminating
405        the class, so got the count wrong. When actually compiling, the reference
406        was subsequently set up correctly.)
407    
408    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
409        it was being rejected as not supported by pcre_dfa_exec(), even though
410        other assertions are supported. I have made pcre_dfa_exec() support
411        (*FAIL).
412    
413    16. The implementation of 13c above involved the invention of a new opcode,
414        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
415        cannot be changed at match time, I realized I could make a small
416        improvement to matching performance by compiling OP_ALLANY instead of
417        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
418        on the OP_ANY path.
419    
420    17. Compiling pcretest on Windows with readline support failed without the
421        following two fixes: (1) Make the unistd.h include conditional on
422        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
423    
424    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
425        ncurses library to be included for pcretest when ReadLine support is
426        requested, but also to allow for it to be overridden. This patch came from
427        Daniel Bergström.
428    
429    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
430        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
431        any errors with the current Unicode tables. Thanks to Peter Kankowski for
432        spotting this.
433    
434    
435    Version 7.6 28-Jan-08
436    ---------------------
437    
438    1.  A character class containing a very large number of characters with
439        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
440        overflow.
441    
442    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
443        HAVE_LONG_LONG is not defined.
444    
445    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
446        bring them up to date and include new features. This patch includes:
447    
448        - Fixed PH's badly added libz and libbz2 support.
449        - Fixed a problem with static linking.
450        - Added pcredemo. [But later removed - see 7 below.]
451        - Fixed dftables problem and added an option.
452        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
453            HAVE_LONG_LONG.
454        - Added readline support for pcretest.
455        - Added an listing of the option settings after cmake has run.
456    
457    4.  A user submitted a patch to Makefile that makes it easy to create
458        "pcre.dll" under mingw when using Configure/Make. I added stuff to
459        Makefile.am that cause it to include this special target, without
460        affecting anything else. Note that the same mingw target plus all
461        the other distribution libraries and programs are now supported
462        when configuring with CMake (see 6 below) instead of with
463        Configure/Make.
464    
465    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
466        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
467        exported in the Windows port". It has not yet been confirmed that the patch
468        solves the problem, but it does no harm.
469    
470    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
471        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
472        with CMake, and also correct the comment about stack recursion.
473    
474    7.  Remove the automatic building of pcredemo from the ./configure system and
475        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
476        of a program that users should build themselves after PCRE is installed, so
477        building it automatically is not really right. What is more, it gave
478        trouble in some build environments.
479    
480    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
481    
482    
483    Version 7.5 10-Jan-08
484    ---------------------
485    
486    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
487        values in parens when parsing an RE using the C++ wrapper."
488    
489    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
490        Characters greater than 255 were excluded from the class instead of being
491        included.
492    
493    3.  The same bug as (2) above applied to negated POSIX classes such as
494        [:^space:].
495    
496    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
497        defined or documented. It seems to have been a typo for PCRE_STATIC, so
498        I have changed it.
499    
500    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
501        first named subpattern) and a construct such as (?&a) would reference the
502        first named subpattern whose name started with "a" (in other words, the
503        length check was missing). Both these problems are fixed. "Subpattern name
504        expected" is now given for (?&) (a zero-length name), and this patch also
505        makes it give the same error for \k'' (previously it complained that that
506        was a reference to a non-existent subpattern).
507    
508    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
509        this is right because (?- can be followed by option settings as well as by
510        digits. I have, however, made the messages clearer.
511    
512    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
513        than the number used in the conditional) now cause a compile-time error.
514        This is actually not compatible with Perl, which accepts such patterns, but
515        treats the conditional as always being FALSE (as PCRE used to), but it
516        seems to me that giving a diagnostic is better.
517    
518    8.  Change "alphameric" to the more common word "alphanumeric" in comments
519        and messages.
520    
521    9.  Fix two occurrences of "backslash" in comments that should have been
522        "backspace".
523    
524    10. Remove two redundant lines of code that can never be obeyed (their function
525        was moved elsewhere).
526    
527    11. The program that makes PCRE's Unicode character property table had a bug
528        which caused it to generate incorrect table entries for sequences of
529        characters that have the same character type, but are in different scripts.
530        It amalgamated them into a single range, with the script of the first of
531        them. In other words, some characters were in the wrong script. There were
532        thirteen such cases, affecting characters in the following ranges:
533    
534          U+002b0 - U+002c1
535          U+0060c - U+0060d
536          U+0061e - U+00612
537          U+0064b - U+0065e
538          U+0074d - U+0076d
539          U+01800 - U+01805
540          U+01d00 - U+01d77
541          U+01d9b - U+01dbf
542          U+0200b - U+0200f
543          U+030fc - U+030fe
544          U+03260 - U+0327f
545          U+0fb46 - U+0fbb1
546          U+10450 - U+1049d
547    
548    12. The -o option (show only the matching part of a line) for pcregrep was not
549        compatible with GNU grep in that, if there was more than one match in a
550        line, it showed only the first of them. It now behaves in the same way as
551        GNU grep.
552    
553    13. If the -o and -v options were combined for pcregrep, it printed a blank
554        line for every non-matching line. GNU grep prints nothing, and pcregrep now
555        does the same. The return code can be used to tell if there were any
556        non-matching lines.
557    
558    14. Added --file-offsets and --line-offsets to pcregrep.
559    
560    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
561        infinitely looping recursion. The bug was that positive lookaheads were not
562        being skipped when checking for a possible empty match (negative lookaheads
563        and both kinds of lookbehind were skipped).
564    
565    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
566        inclusion of <windows.h> to before rather than after the definition of
567        INVALID_FILE_ATTRIBUTES (patch from David Byron).
568    
569    17. Specifying a possessive quantifier with a specific limit for a Unicode
570        character property caused pcre_compile() to compile bad code, which led at
571        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
572        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
573        caused the error; without that there was no problem.
574    
575    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
576    
577    19. Added --enable-pcretest-libreadline.
578    
579    20. In pcrecpp.cc, the variable 'count' was incremented twice in
580        RE::GlobalReplace(). As a result, the number of replacements returned was
581        double what it should be. I removed one of the increments, but Craig sent a
582        later patch that removed the other one (the right fix) and added unit tests
583        that check the return values (which was not done before).
584    
585    21. Several CMake things:
586    
587        (1) Arranged that, when cmake is used on Unix, the libraries end up with
588            the names libpcre and libpcreposix, not just pcre and pcreposix.
589    
590        (2) The above change means that pcretest and pcregrep are now correctly
591            linked with the newly-built libraries, not previously installed ones.
592    
593        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
594    
595    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
596        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
597        UTF-8 newline character). The key issue is that the pattern starts .*;
598        this means that the match must be either at the beginning, or after a
599        newline. The bug was in the code for advancing after a failed match and
600        checking that the new position followed a newline. It was not taking
601        account of UTF-8 characters correctly.
602    
603    23. PCRE was behaving differently from Perl in the way it recognized POSIX
604        character classes. PCRE was not treating the sequence [:...:] as a
605        character class unless the ... were all letters. Perl, however, seems to
606        allow any characters between [: and :], though of course it rejects as
607        unknown any "names" that contain non-letters, because all the known class
608        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
609        for example, whereas PCRE did not - it did not recognize a POSIX character
610        class. This seemed a bit dangerous, so the code has been changed to be
611        closer to Perl. The behaviour is not identical to Perl, because PCRE will
612        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
613        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
614        Perl does, and where it didn't before.
615    
616    24. Rewrite so as to remove the single use of %n from pcregrep because in some
617        Windows environments %n is disabled by default.
618    
619    
620    Version 7.4 21-Sep-07
621    ---------------------
622    
623    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
624        means that a class such as [\s] counted as "explicit reference to CR or
625        LF". That isn't really right - the whole point of the change was to try to
626        help when there was an actual mention of one of the two characters. So now
627        the change happens only if \r or \n (or a literal CR or LF) character is
628        encountered.
629    
630    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
631        of both had grown to the point where there were only 3 bits left.
632        Fortunately, there was spare space in the data structure, and so I have
633        moved the internal flags into a new 16-bit field to free up more option
634        bits.
635    
636    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
637        but did not set the internal JCHANGED flag - either of these is enough to
638        control the way the "get" function works - but the PCRE_INFO_JCHANGED
639        facility is supposed to tell if (?J) was ever used, so now (?J) at the
640        start sets both bits.
641    
642    4.  Added options (at build time, compile time, exec time) to change \R from
643        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
644    
645    5.  doc/pcresyntax.html was missing from the distribution.
646    
647    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
648        compatibility, even though it is no longer used.
649    
650    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
651        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
652        windows.h file is present (where different names are used). [This was
653        reversed later after testing - see 16 below.]
654    
655    8.  Changed all #include <config.h> to #include "config.h". There were also
656        some further <pcre.h> cases that I changed to "pcre.h".
657    
658    9.  When pcregrep was used with the --colour option, it missed the line ending
659        sequence off the lines that it output.
660    
661    10. It was pointed out to me that arrays of string pointers cause lots of
662        relocations when a shared library is dynamically loaded. A technique of
663        using a single long string with a table of offsets can drastically reduce
664        these. I have refactored PCRE in four places to do this. The result is
665        dramatic:
666    
667          Originally:                          290
668          After changing UCP table:            187
669          After changing error message table:   43
670          After changing table of "verbs"       36
671          After changing table of Posix names   22
672    
673        Thanks to the folks working on Gregex for glib for this insight.
674    
675    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
676        unicode-properties was also set.
677    
678    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
679    
680    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
681        checked only for CRLF.
682    
683    14. Added casts to pcretest.c to avoid compiler warnings.
684    
685    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
686    
687    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
688        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
689        entirely. This removes changes made in 7 above.
690    
691    17. The CMake files have been updated, and there is now more information about
692        building with CMake in the NON-UNIX-USE document.
693    
694    
695    Version 7.3 28-Aug-07
696    ---------------------
697    
698     1. In the rejigging of the build system that eventually resulted in 7.1, the
699        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
700        brackets there is not right, since it causes compilers to look for an
701        installed pcre.h, not the version that is in the source that is being
702        compiled (which of course may be different). I have changed it back to:
703    
704          #include "pcre.h"
705    
706        I have a vague recollection that the change was concerned with compiling in
707        different directories, but in the new build system, that is taken care of
708        by the VPATH setting the Makefile.
709    
710     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
711        when the subject happened to end in the byte 0x85 (e.g. if the last
712        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
713        characters but of course it shouldn't be taken as a newline when it is part
714        of another character. The bug was that, for an unlimited repeat of . in
715        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
716        characters when looking for a newline.
717    
718     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
719    
720     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
721        in debug output.
722    
723     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
724        long printing in the pcrecpp unittest when running under MinGW.
725    
726     6. ESC_K was left out of the EBCDIC table.
727    
728     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
729        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
730        limit also applies to "virtual nesting" when a pattern is recursive, and in
731        this case 1000 isn't so big. I have been able to remove this limit at the
732        expense of backing off one optimization in certain circumstances. Normally,
733        when pcre_exec() would call its internal match() function recursively and
734        immediately return the result unconditionally, it uses a "tail recursion"
735        feature to save stack. However, when a subpattern that can match an empty
736        string has an unlimited repetition quantifier, it no longer makes this
737        optimization. That gives it a stack frame in which to save the data for
738        checking that an empty string has been matched. Previously this was taken
739        from the 1000-entry workspace that had been reserved. So now there is no
740        explicit limit, but more stack is used.
741    
742     8. Applied Daniel's patches to solve problems with the import/export magic
743        syntax that is required for Windows, and which was going wrong for the
744        pcreposix and pcrecpp parts of the library. These were overlooked when this
745        problem was solved for the main library.
746    
747     9. There were some crude static tests to avoid integer overflow when computing
748        the size of patterns that contain repeated groups with explicit upper
749        limits. As the maximum quantifier is 65535, the maximum group length was
750        set at 30,000 so that the product of these two numbers did not overflow a
751        32-bit integer. However, it turns out that people want to use groups that
752        are longer than 30,000 bytes (though not repeat them that many times).
753        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
754        made it possible to implement the integer overflow checks in a much more
755        dynamic way, which I have now done. The artificial limitation on group
756        length has been removed - we now have only the limit on the total length of
757        the compiled pattern, which depends on the LINK_SIZE setting.
758    
759    10. Fixed a bug in the documentation for get/copy named substring when
760        duplicate names are permitted. If none of the named substrings are set, the
761        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
762        empty string.
763    
764    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
765        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
766        because the ] is interpreted as the first data character and the
767        terminating ] is not found. PCRE has been made compatible with Perl in this
768        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
769        cause memory overwriting.
770    
771    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
772        string has been matched (to stop an infinite loop). It was not recognizing
773        a conditional subpattern that could match an empty string if that
774        subpattern was within another subpattern. For example, it looped when
775        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
776        condition was not nested. This bug has been fixed.
777    
778    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
779        past the start of the subject in the presence of bytes with the top bit
780        set, for example "\x8aBCD".
781    
782    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
783        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
784    
785    14. Optimized (?!) to (*FAIL).
786    
787    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
788        This restricts code points to be within the range 0 to 0x10FFFF, excluding
789        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
790        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
791        does: it's just the validity check that is more restrictive.
792    
793    16. Inserted checks for integer overflows during escape sequence (backslash)
794        processing, and also fixed erroneous offset values for syntax errors during
795        backslash processing.
796    
797    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
798        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
799    
800    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
801        caused an overrun.
802    
803    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
804        something other than just ASCII characters) inside a group that had an
805        unlimited repeat caused a loop at compile time (while checking to see
806        whether the group could match an empty string).
807    
808    20. Debugging a pattern containing \p or \P could cause a crash. For example,
809        [\P{Any}] did so. (Error in the code for printing property names.)
810    
811    21. An orphan \E inside a character class could cause a crash.
812    
813    22. A repeated capturing bracket such as (A)? could cause a wild memory
814        reference during compilation.
815    
816    23. There are several functions in pcre_compile() that scan along a compiled
817        expression for various reasons (e.g. to see if it's fixed length for look
818        behind). There were bugs in these functions when a repeated \p or \P was
819        present in the pattern. These operators have additional parameters compared
820        with \d, etc, and these were not being taken into account when moving along
821        the compiled data. Specifically:
822    
823        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
824            length.
825    
826        (b) An item such as \pL+ within a repeated group could cause crashes or
827            loops.
828    
829        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
830            "reference to non-existent subpattern" error.
831    
832        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
833    
834    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
835        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
836    
837    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
838    
839    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
840        character were causing crashes (broken optimization).
841    
842    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
843        \p or \P) caused a compile-time loop.
844    
845    28. More problems have arisen in unanchored patterns when CRLF is a valid line
846        break. For example, the unstudied pattern [\r\n]A does not match the string
847        "\r\nA" because change 7.0/46 below moves the current point on by two
848        characters after failing to match at the start. However, the pattern \nA
849        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
850        the same is true. There doesn't seem any very clean way out of this, but
851        what I have chosen to do makes the common cases work: PCRE now takes note
852        of whether there can be an explicit match for \r or \n anywhere in the
853        pattern, and if so, 7.0/46 no longer applies. As part of this change,
854        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
855        pattern has explicit CR or LF references.
856    
857    29. Added (*CR) etc for changing newline setting at start of pattern.
858    
859    
860    Version 7.2 19-Jun-07
861    ---------------------
862    
863     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
864        which is apparently normally available under Windows.
865    
866     2. Re-jig the pcregrep tests with different newline settings in an attempt
867        to make them independent of the local environment's newline setting.
868    
869     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
870    
871     4. Some of the "internals" tests were previously cut out when the link size
872        was not 2, because the output contained actual offsets. The recent new
873        "Z" feature of pcretest means that these can be cut out, making the tests
874        usable with all link sizes.
875    
876     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
877        stack recursion. This gives a massive performance boost under BSD, but just
878        a small improvement under Linux. However, it saves one field in the frame
879        in all cases.
880    
881     6. Added more features from the forthcoming Perl 5.10:
882    
883        (a) (?-n) (where n is a string of digits) is a relative subroutine or
884            recursion call. It refers to the nth most recently opened parentheses.
885    
886        (b) (?+n) is also a relative subroutine call; it refers to the nth next
887            to be opened parentheses.
888    
889        (c) Conditions that refer to capturing parentheses can be specified
890            relatively, for example, (?(-2)... or (?(+3)...
891    
892        (d) \K resets the start of the current match so that everything before
893            is not part of it.
894    
895        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
896    
897        (f) \g{name} is another synonym - part of Perl 5.10's unification of
898            reference syntax.
899    
900        (g) (?| introduces a group in which the numbering of parentheses in each
901            alternative starts with the same number.
902    
903        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
904    
905     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
906        PCRE_INFO_JCHANGED.
907    
908     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
909        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
910        for detecting groups that can match an empty string.
911    
912     9. A pattern with a very large number of alternatives (more than several
913        hundred) was running out of internal workspace during the pre-compile
914        phase, where pcre_compile() figures out how much memory will be needed. A
915        bit of new cunning has reduced the workspace needed for groups with
916        alternatives. The 1000-alternative test pattern now uses 12 bytes of
917        workspace instead of running out of the 4096 that are available.
918    
919    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
920    
921    11. Applied patch from Google to remove an optimization that didn't quite work.
922        The report of the bug said:
923    
924          pcrecpp::RE("a*").FullMatch("aaa") matches, while
925          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
926          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
927    
928    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
929        it matched the wrong number of bytes.
930    
931    
932    Version 7.1 24-Apr-07
933    ---------------------
934    
935     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
936        that is more "standard", making use of automake and other Autotools. There
937        is some re-arrangement of the files and adjustment of comments consequent
938        on this.
939    
940     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
941        for recursive directory scanning broke on some systems because the files
942        are not scanned in any specific order and on different systems the order
943        was different. A call to "sort" has been inserted into RunGrepTest for the
944        approprate test as a short-term fix. In the longer term there may be an
945        alternative.
946    
947     3. I had an email from Eric Raymond about problems translating some of PCRE's
948        man pages to HTML (despite the fact that I distribute HTML pages, some
949        people do their own conversions for various reasons). The problems
950        concerned the use of low-level troff macros .br and .in. I have therefore
951        removed all such uses from the man pages (some were redundant, some could
952        be replaced by .nf/.fi pairs). The 132html script that I use to generate
953        HTML has been updated to handle .nf/.fi and to complain if it encounters
954        .br or .in.
955    
956     4. Updated comments in configure.ac that get placed in config.h.in and also
957        arranged for config.h to be included in the distribution, with the name
958        config.h.generic, for the benefit of those who have to compile without
959        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
960    
961     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
962        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
963        makevp.bat for the current PCRE, using the additional files
964        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
965    
966     6. A Windows user reported a minor discrepancy with test 2, which turned out
967        to be caused by a trailing space on an input line that had got lost in his
968        copy. The trailing space was an accident, so I've just removed it.
969    
970     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
971        that is needed.
972    
973     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
974        as "const" (a) because they are and (b) because it helps the PHP
975        maintainers who have recently made a script to detect big data structures
976        in the php code that should be moved to the .rodata section. I remembered
977        to update Builducptable as well, so it won't revert if ucptable.h is ever
978        re-created.
979    
980     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
981        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
982        order to be able to cut out the UTF-8 tables in the latter when UTF-8
983        support is not required. This saves 1.5-2K of code, which is important in
984        some applications.
985    
986        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
987        so as not to refer to the tables, even though these functions will never be
988        called when UTF-8 support is disabled. Otherwise there are problems with a
989        shared library.
990    
991    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
992    
993        (a) It was defining its arguments as char * instead of void *.
994    
995        (b) It was assuming that all moves were upwards in memory; this was true
996            a long time ago when I wrote it, but is no longer the case.
997    
998        The emulated memove() is provided for those environments that have neither
999        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1000        is clearly not the case, as these two bugs were recently reported.
1001    
1002    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1003        and Detrail to create the HTML documentation, the .txt form of the man
1004        pages, and it removes trailing spaces from listed files. It also creates
1005        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1006        case, it wraps all the #defines with #ifndefs. This script should be run
1007        before "make dist".
1008    
1009    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1010        with Unicode property support.
1011    
1012        (a) For a maximizing quantifier, if the two different cases of the
1013            character were of different lengths in their UTF-8 codings (there are
1014            some cases like this - I found 11), and the matching function had to
1015            back up over a mixture of the two cases, it incorrectly assumed they
1016            were both the same length.
1017    
1018        (b) When PCRE was configured to use the heap rather than the stack for
1019            recursion during matching, it was not correctly preserving the data for
1020            the other case of a UTF-8 character when checking ahead for a match
1021            while processing a minimizing repeat. If the check also involved
1022            matching a wide character, but failed, corruption could cause an
1023            erroneous result when trying to check for a repeat of the original
1024            character.
1025    
1026    13. Some tidying changes to the testing mechanism:
1027    
1028        (a) The RunTest script now detects the internal link size and whether there
1029            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1030            values substituted by "configure". (The RunGrepTest script already did
1031            this for UTF-8.) The configure.ac script no longer substitutes the
1032            relevant variables.
1033    
1034        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1035            with length and offset values. This means that the output is different
1036            for different internal link sizes. Test 2 is skipped for link sizes
1037            other than 2 because of this, bypassing the problem. Unfortunately,
1038            there was also a test in test 3 (the locale tests) that used /B and
1039            failed for link sizes other than 2. Rather than cut the whole test out,
1040            I have added a new /Z option to pcretest that replaces the length and
1041            offset values with spaces. This is now used to make test 3 independent
1042            of link size. (Test 2 will be tidied up later.)
1043    
1044    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1045        segmentation fault instead of returning the appropriate error message.
1046    
1047    15. In multiline mode when the newline sequence was set to "any", the pattern
1048        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1049        This doesn't seem right; it now treats the CRLF combination as the line
1050        ending, and so does not match in that case. It's only a pattern such as ^$
1051        that would hit this one: something like ^ABC$ would have failed after \r
1052        and then tried again after \r\n.
1053    
1054    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1055        in an attempt to make files that differ only in their line terminators
1056        compare equal. This works on Linux.
1057    
1058    17. Under certain error circumstances pcregrep might try to free random memory
1059        as it exited. This is now fixed, thanks to valgrind.
1060    
1061    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1062        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1063        was because its rules for how to advance for /g after matching an empty
1064        string at the end of a line did not allow for this case. They now check for
1065        it specially.
1066    
1067    20. pcretest is supposed to handle patterns and data of any length, by
1068        extending its buffers when necessary. It was getting this wrong when the
1069        buffer for a data line had to be extended.
1070    
1071    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1072        CRLF as a newline sequence.
1073    
1074    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1075        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1076        I have nevertheless tidied it up.
1077    
1078    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1079    
1080    24. Added a man page for pcre-config.
1081    
1082    
1083    Version 7.0 19-Dec-06
1084    ---------------------
1085    
1086     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1087        moving to gcc 4.1.1.
1088    
1089     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1090        sys/time.h, which is documented as needed for this function. It doesn't
1091        seem to matter on Linux, but it showed up on some releases of OS X.
1092    
1093     3. It seems that there are systems where bytes whose values are greater than
1094        127 match isprint() in the "C" locale. The "C" locale should be the
1095        default when a C program starts up. In most systems, only ASCII printing
1096        characters match isprint(). This difference caused the output from pcretest
1097        to vary, making some of the tests fail. I have changed pcretest so that:
1098    
1099        (a) When it is outputting text in the compiled version of a pattern, bytes
1100            other than 32-126 are always shown as hex escapes.
1101    
1102        (b) When it is outputting text that is a matched part of a subject string,
1103            it does the same, unless a different locale has been set for the match
1104            (using the /L modifier). In this case, it uses isprint() to decide.
1105    
1106     4. Fixed a major bug that caused incorrect computation of the amount of memory
1107        required for a compiled pattern when options that changed within the
1108        pattern affected the logic of the preliminary scan that determines the
1109        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1110        that the computed length was too small. The symptoms of this bug were
1111        either the PCRE error "internal error: code overflow" from pcre_compile(),
1112        or a glibc crash with a message such as "pcretest: free(): invalid next
1113        size (fast)". Examples of patterns that provoked this bug (shown in
1114        pcretest format) are:
1115    
1116          /(?-x: )/x
1117          /(?x)(?-x: \s*#\s*)/
1118          /((?i)[\x{c0}])/8
1119          /(?i:[\x{c0}])/8
1120    
1121        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1122        is now done differently.
1123    
1124     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1125        wrapper classes; (b) implement a new function in the C++ scanner that is
1126        more efficient than the old way of doing things because it avoids levels of
1127        recursion in the regex matching; (c) add a paragraph to the documentation
1128        for the FullMatch() function.
1129    
1130     6. The escape sequence \n was being treated as whatever was defined as
1131        "newline". Not only was this contrary to the documentation, which states
1132        that \n is character 10 (hex 0A), but it also went horribly wrong when
1133        "newline" was defined as CRLF. This has been fixed.
1134    
1135     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1136        was being set to -1 for the "end of line" case (supposedly a value that no
1137        character can have). Though this value is never used (the check for end of
1138        line is "zero bytes in current character"), it caused compiler complaints.
1139        I've changed it to 0xffffffff.
1140    
1141     8. In pcre_version.c, the version string was being built by a sequence of
1142        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1143        string (as it is for production releases) called a macro with an empty
1144        argument. The C standard says the result of this is undefined. The gcc
1145        compiler treats it as an empty string (which was what was wanted) but it is
1146        reported that Visual C gives an error. The source has been hacked around to
1147        avoid this problem.
1148    
1149     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1150        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1151        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1152        of them did).
1153    
1154    10. Originally, pcretest opened its input and output without "b"; then I was
1155        told that "b" was needed in some environments, so it was added for release
1156        5.0 to both the input and output. (It makes no difference on Unix-like
1157        systems.) Later I was told that it is wrong for the input on Windows. I've
1158        now abstracted the modes into two macros, to make it easier to fiddle with
1159        them, and removed "b" from the input mode under Windows.
1160    
1161    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1162    
1163    12. Added -help and --help to pcretest as an official way of being reminded
1164        of the options.
1165    
1166    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1167        and pcrecpp.cc because they annoy compilers at high warning levels.
1168    
1169    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1170    
1171    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1172        scripts are not C programs :-) and which was not noticed because it works
1173        on Linux.
1174    
1175    16. pcretest is supposed to handle any length of pattern and data line (as one
1176        line or as a continued sequence of lines) by extending its input buffer if
1177        necessary. This feature was broken for very long pattern lines, leading to
1178        a string of junk being passed to pcre_compile() if the pattern was longer
1179        than about 50K.
1180    
1181    17. I have done a major re-factoring of the way pcre_compile() computes the
1182        amount of memory needed for a compiled pattern. Previously, there was code
1183        that made a preliminary scan of the pattern in order to do this. That was
1184        OK when PCRE was new, but as the facilities have expanded, it has become
1185        harder and harder to keep it in step with the real compile phase, and there
1186        have been a number of bugs (see for example, 4 above). I have now found a
1187        cunning way of running the real compile function in a "fake" mode that
1188        enables it to compute how much memory it would need, while actually only
1189        ever using a few hundred bytes of working memory and without too many
1190        tests of the mode. This should make future maintenance and development
1191        easier. A side effect of this work is that the limit of 200 on the nesting
1192        depth of parentheses has been removed (though this was never a serious
1193        limitation, I suspect). However, there is a downside: pcre_compile() now
1194        runs more slowly than before (30% or more, depending on the pattern). I
1195        hope this isn't a big issue. There is no effect on runtime performance.
1196    
1197    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1198        newline (only possible for the last line of a file) and it was a
1199        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1200    
1201    19. Added additional timing features to pcretest. (1) The -tm option now times
1202        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1203        separate command line item, by a number that specifies the number of
1204        repeats to use when timing. The default is 50000; this gives better
1205        precision, but takes uncomfortably long for very large patterns.
1206    
1207    20. Extended pcre_study() to be more clever in cases where a branch of a
1208        subpattern has no definite first character. For example, (a*|b*)[cd] would
1209        previously give no result from pcre_study(). Now it recognizes that the
1210        first character must be a, b, c, or d.
1211    
1212    21. There was an incorrect error "recursive call could loop indefinitely" if
1213        a subpattern (or the entire pattern) that was being tested for matching an
1214        empty string contained only one non-empty item after a nested subpattern.
1215        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1216        incorrectly, because the \d was being skipped in the check.
1217    
1218    22. The pcretest program now has a new pattern option /B and a command line
1219        option -b, which is equivalent to adding /B to every pattern. This causes
1220        it to show the compiled bytecode, without the additional information that
1221        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1222        is the same as /B/I).
1223    
1224    23. A new optimization is now able automatically to treat some sequences such
1225        as a*b as a*+b. More specifically, if something simple (such as a character
1226        or a simple class like \d) has an unlimited quantifier, and is followed by
1227        something that cannot possibly match the quantified thing, the quantifier
1228        is automatically "possessified".
1229    
1230    24. A recursive reference to a subpattern whose number was greater than 39
1231        went wrong under certain circumstances in UTF-8 mode. This bug could also
1232        have affected the operation of pcre_study().
1233    
1234    25. Realized that a little bit of performance could be had by replacing
1235        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1236    
1237    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1238    
1239    27. Possessive quantifiers such as a++ were previously implemented by turning
1240        them into atomic groups such as ($>a+). Now they have their own opcodes,
1241        which improves performance. This includes the automatically created ones
1242        from 23 above.
1243    
1244    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1245        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1246        the first matched character to be a colon. This applied both to named and
1247        numbered groups.
1248    
1249    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1250    
1251    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1252        building PCRE on Windows easier, so I have included it in the distribution.
1253    
1254    31. There is now a check in pcretest against a ridiculously large number being
1255        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1256        loop, the loop is abandoned.
1257    
1258    32. Forward references to subpatterns in conditions such as (?(2)...) where
1259        subpattern 2 is defined later cause pcre_compile() to search forwards in
1260        the pattern for the relevant set of parentheses. This search went wrong
1261        when there were unescaped parentheses in a character class, parentheses
1262        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1263    
1264    33. "Subroutine" calls and backreferences were previously restricted to
1265        referencing subpatterns earlier in the regex. This restriction has now
1266        been removed.
1267    
1268    34. Added a number of extra features that are going to be in Perl 5.10. On the
1269        whole, these are just syntactic alternatives for features that PCRE had
1270        previously implemented using the Python syntax or my own invention. The
1271        other formats are all retained for compatibility.
1272    
1273        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1274            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1275            also .NET compatible.
1276    
1277        (b) A recursion or subroutine call to a named group can now be defined as
1278            (?&name) as well as (?P>name).
1279    
1280        (c) A backreference to a named group can now be defined as \k<name> or
1281            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1282            5.10, are also .NET compatible.
1283    
1284        (d) A conditional reference to a named group can now use the syntax
1285            (?(<name>) or (?('name') as well as (?(name).
1286    
1287        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1288            groups (named and numbered) that are never evaluated inline, but can be
1289            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1290            is always false. There may be only one alternative in such a group.
1291    
1292        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1293            as the simple (?(R). The condition is true only if the most recent
1294            recursion is that of the given number or name. It does not search out
1295            through the entire recursion stack.
1296    
1297        (g) The escape \gN or \g{N} has been added, where N is a positive or
1298            negative number, specifying an absolute or relative reference.
1299    
1300    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1301        some "unreachable code" warnings.
1302    
1303    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1304        things, this adds five new scripts.
1305    
1306    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1307        There were also incompatibilities regarding the handling of \Q..\E inside
1308        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1309        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1310    
1311    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1312        matches an empty string, and forcibly breaks the loop. There were bugs in
1313        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1314        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1315        separate and independent bugs (that affected different cases) have been
1316        fixed.
1317    
1318    39. Refactored the code to abolish the use of different opcodes for small
1319        capturing bracket numbers. This is a tidy that I avoided doing when I
1320        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1321        The new approach is not only tidier, it makes it possible to reduce the
1322        memory needed to fix the previous bug (38).
1323    
1324    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1325        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1326        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1327        mode.
1328    
1329    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1330        report.
1331    
1332    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1333        copy construction and assignment in the C++ wrapper.
1334    
1335    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1336        couple of bugs that could have given wrong results in the "--newline=crlf"
1337        case.
1338    
1339    44. Added a number of casts and did some reorganization of signed/unsigned int
1340        variables following suggestions from Dair Grant. Also renamed the variable
1341        "this" as "item" because it is a C++ keyword.
1342    
1343    45. Arranged for dftables to add
1344    
1345          #include "pcre_internal.h"
1346    
1347        to pcre_chartables.c because without it, gcc 4.x may remove the array
1348        definition from the final binary if PCRE is built into a static library and
1349        dead code stripping is activated.
1350    
1351    46. For an unanchored pattern, if a match attempt fails at the start of a
1352        newline sequence, and the newline setting is CRLF or ANY, and the next two
1353        characters are CRLF, advance by two characters instead of one.
1354    
1355    
1356    Version 6.7 04-Jul-06
1357    ---------------------
1358    
1359     1. In order to handle tests when input lines are enormously long, pcretest has
1360        been re-factored so that it automatically extends its buffers when
1361        necessary. The code is crude, but this _is_ just a test program. The
1362        default size has been increased from 32K to 50K.
1363    
1364     2. The code in pcre_study() was using the value of the re argument before
1365        testing it for NULL. (Of course, in any sensible call of the function, it
1366        won't be NULL.)
1367    
1368     3. The memmove() emulation function in pcre_internal.h, which is used on
1369        systems that lack both memmove() and bcopy() - that is, hardly ever -
1370        was missing a "static" storage class specifier.
1371    
1372     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1373        containing an extended class (one that cannot be represented by a bitmap
1374        because it contains high-valued characters or Unicode property items, e.g.
1375        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1376        pattern, but PCRE should not loop if you do not (it no longer does).
1377        [Detail: two cases were found: (a) a repeated subpattern containing an
1378        extended class; (b) a recursive reference to a subpattern that followed a
1379        previous extended class. It wasn't skipping over the extended class
1380        correctly when UTF-8 mode was not set.]
1381    
1382     5. A negated single-character class was not being recognized as fixed-length
1383        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1384        compile error "lookbehind assertion is not fixed length".
1385    
1386     6. The RunPerlTest auxiliary script was showing an unexpected difference
1387        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1388        write a Perl script that can interpret lines of an input file either as
1389        byte characters or as UTF-8, which is what "perltest" was being required to
1390        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1391        can't do is switch easily at run time between having the "use utf8;" pragma
1392        or not. In the end, I fudged it by using the RunPerlTest script to insert
1393        "use utf8;" explicitly for the UTF-8 tests.
1394    
1395     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1396        the end of the subject string, contrary to the documentation and to what
1397        Perl does. This was true of both matching functions. Now it matches only at
1398        the start of the subject and immediately after *internal* newlines.
1399    
1400     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1401        a pointer to an int instead of a pointer to an unsigned long int. This
1402        caused problems on 64-bit systems.
1403    
1404     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1405        instance of the 'standard' template library not being so standard".
1406    
1407    10. There was no check on the number of named subpatterns nor the maximum
1408        length of a subpattern name. The product of these values is used to compute
1409        the size of the memory block for a compiled pattern. By supplying a very
1410        long subpattern name and a large number of named subpatterns, the size
1411        computation could be caused to overflow. This is now prevented by limiting
1412        the length of names to 32 characters, and the number of named subpatterns
1413        to 10,000.
1414    
1415    11. Subpatterns that are repeated with specific counts have to be replicated in
1416        the compiled pattern. The size of memory for this was computed from the
1417        length of the subpattern and the repeat count. The latter is limited to
1418        65535, but there was no limit on the former, meaning that integer overflow
1419        could in principle occur. The compiled length of a repeated subpattern is
1420        now limited to 30,000 bytes in order to prevent this.
1421    
1422    12. Added the optional facility to have named substrings with the same name.
1423    
1424    13. Added the ability to use a named substring as a condition, using the
1425        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1426        are numbers (not recommended). Forward references are permitted.
1427    
1428    14. Added forward references in named backreferences (if you see what I mean).
1429    
1430    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1431        pattern could run off the end of the subject. For example, the pattern
1432        "(?s)(.{1,5})"8 did this with the subject "ab".
1433    
1434    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1435        PCRE_CASELESS was set when matching characters that were quantified with ?
1436        or *.
1437    
1438    17. A character class other than a single negated character that had a minimum
1439        but no maximum quantifier - for example [ab]{6,} - was not handled
1440        correctly by pce_dfa_exec(). It would match only one character.
1441    
1442    18. A valid (though odd) pattern that looked like a POSIX character
1443        class but used an invalid character after [ (for example [[,abc,]]) caused
1444        pcre_compile() to give the error "Failed: internal error: code overflow" or
1445        in some cases to crash with a glibc free() error. This could even happen if
1446        the pattern terminated after [[ but there just happened to be a sequence of
1447        letters, a binary zero, and a closing ] in the memory that followed.
1448    
1449    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1450        over the years. Originally (before any Unicode support), just the bottom 8
1451        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1452        output from "man perlunicode" includes this:
1453    
1454          The regular expression compiler produces polymorphic opcodes.  That
1455          is, the pattern adapts to the data and automatically switches to
1456          the Unicode character scheme when presented with Unicode data--or
1457          instead uses a traditional byte scheme when presented with byte
1458          data.
1459    
1460        Sadly, a wide octal escape does not cause a switch, and in a string with
1461        no other multibyte characters, these octal escapes are treated as before.
1462        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1463        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1464        Unicode string.
1465    
1466        I have not perpetrated such confusion in PCRE. Up till now, it took just
1467        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1468        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1469        translate to the appropriate multibyte character.
1470    
1471    29. Applied some refactoring to reduce the number of warnings from Microsoft
1472        and Borland compilers. This has included removing the fudge introduced
1473        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1474        a warning about an unused variable.
1475    
1476    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1477        characters since release 4.0, because Perl (from release 5.004) does not.
1478        [Or at least, is documented not to: some releases seem to be in conflict
1479        with the documentation.] However, when a pattern was studied with
1480        pcre_study() and all its branches started with \s, PCRE still included VT
1481        as a possible starting character. Of course, this did no harm; it just
1482        caused an unnecessary match attempt.
1483    
1484    22. Removed a now-redundant internal flag bit that recorded the fact that case
1485        dependency changed within the pattern. This was once needed for "required
1486        byte" processing, but is no longer used. This recovers a now-scarce options
1487        bit. Also moved the least significant internal flag bit to the most-
1488        significant bit of the word, which was not previously used (hangover from
1489        the days when it was an int rather than a uint) to free up another bit for
1490        the future.
1491    
1492    23. Added support for CRLF line endings as well as CR and LF. As well as the
1493        default being selectable at build time, it can now be changed at runtime
1494        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1495        specify that it is scanning data with non-default line endings.
1496    
1497    24. Changed the definition of CXXLINK to make it agree with the definition of
1498        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1499    
1500    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1501        recursions. This makes a big different to stack usage for some patterns.
1502    
1503    26. If a subpattern containing a named recursion or subroutine reference such
1504        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1505        the space required for the compiled pattern went wrong and gave too small a
1506        value. Depending on the environment, this could lead to "Failed: internal
1507        error: code overflow at offset 49" or "glibc detected double free or
1508        corruption" errors.
1509    
1510    27. Applied patches from Google (a) to support the new newline modes and (b) to
1511        advance over multibyte UTF-8 characters in GlobalReplace.
1512    
1513    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1514        difference for some implementation of PCRE in some Windows version.
1515    
1516    29. Added some extra testing facilities to pcretest:
1517    
1518        \q<number>   in a data line sets the "match limit" value
1519        \Q<number>   in a data line sets the "match recursion limt" value
1520        -S <number>  sets the stack size, where <number> is in megabytes
1521    
1522        The -S option isn't available for Windows.
1523    
1524    
1525    Version 6.6 06-Feb-06
1526    ---------------------
1527    
1528     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1529        in pcreposix.h. I have copied the definition from pcre.h.
1530    
1531     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1532        because pcre.h is no longer a built file.
1533    
1534     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1535        not normally included in the compiled code.
1536    
1537    
1538    Version 6.5 01-Feb-06
1539    ---------------------
1540    
1541     1. When using the partial match feature with pcre_dfa_exec(), it was not
1542        anchoring the second and subsequent partial matches at the new starting
1543        point. This could lead to incorrect results. For example, with the pattern
1544        /1234/, partially matching against "123" and then "a4" gave a match.
1545    
1546     2. Changes to pcregrep:
1547    
1548        (a) All non-match returns from pcre_exec() were being treated as failures
1549            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1550            error message is output. Some extra information is given for the
1551            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1552            probably the only errors that are likely to be caused by users (by
1553            specifying a regex that has nested indefinite repeats, for instance).
1554            If there are more than 20 of these errors, pcregrep is abandoned.
1555    
1556        (b) A binary zero was treated as data while matching, but terminated the
1557            output line if it was written out. This has been fixed: binary zeroes
1558            are now no different to any other data bytes.
1559    
1560        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1561            used to set a locale for matching. The --locale=xxxx long option has
1562            been added (no short equivalent) to specify a locale explicitly on the
1563            pcregrep command, overriding the environment variables.
1564    
1565        (d) When -B was used with -n, some line numbers in the output were one less
1566            than they should have been.
1567    
1568        (e) Added the -o (--only-matching) option.
1569    
1570        (f) If -A or -C was used with -c (count only), some lines of context were
1571            accidentally printed for the final match.
1572    
1573        (g) Added the -H (--with-filename) option.
1574    
1575        (h) The combination of options -rh failed to suppress file names for files
1576            that were found from directory arguments.
1577    
1578        (i) Added the -D (--devices) and -d (--directories) options.
1579    
1580        (j) Added the -F (--fixed-strings) option.
1581    
1582        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1583    
1584        (l) Added the --colo(u)r option.
1585    
1586        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1587            is not present by default.
1588    
1589     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1590        items such as (?R) or (?1), when the recursion could match a number of
1591        alternatives. If it matched one of the alternatives, but subsequently,
1592        outside the recursion, there was a failure, the code tried to back up into
1593        the recursion. However, because of the way PCRE is implemented, this is not
1594        possible, and the result was an incorrect result from the match.
1595    
1596        In order to prevent this happening, the specification of recursion has
1597        been changed so that all such subpatterns are automatically treated as
1598        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1599    
1600     4. I had overlooked the fact that, in some locales, there are characters for
1601        which isalpha() is true but neither isupper() nor islower() are true. In
1602        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1603        and ordfeminine) are like this. This affected the treatment of \w and \W
1604        when they appeared in character classes, but not when they appeared outside
1605        a character class. The bit map for "word" characters is now created
1606        separately from the results of isalnum() instead of just taking it from the
1607        upper, lower, and digit maps. (Plus the underscore character, of course.)
1608    
1609     5. The above bug also affected the handling of POSIX character classes such as
1610        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1611        permanent tables. Instead, the bit maps for such a class were previously
1612        created as the appropriate unions of the upper, lower, and digit bitmaps.
1613        Now they are created by subtraction from the [[:word:]] class, which has
1614        its own bitmap.
1615    
1616     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1617        It is created by subtracting the vertical space characters (\x09, \x0a,
1618        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1619        subtraction was done in the overall bitmap for a character class, meaning
1620        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1621        be recognized. This bug has been fixed.
1622    
1623     7. Patches from the folks at Google:
1624    
1625          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1626          real life, but is still worth protecting against".
1627    
1628          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1629          regular expressions".
1630    
1631          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1632          have it.
1633    
1634          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1635          "configure" and the latter not, in order to fix a problem somebody had
1636          with compiling the Arg class on HP-UX.
1637    
1638          (e) Improve the error-handling of the C++ wrapper a little bit.
1639    
1640          (f) New tests for checking recursion limiting.
1641    
1642     8. The pcre_memmove() function, which is used only if the environment does not
1643        have a standard memmove() function (and is therefore rarely compiled),
1644        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1645        returning a result (though PCRE never actually uses the result).
1646    
1647     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1648        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1649        returned instead of calling malloc() with an overflowing number that would
1650        most likely cause subsequent chaos.
1651    
1652    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1653    
1654    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1655        with this option is matched, the nmatch and pmatch options of regexec() are
1656        ignored.
1657    
1658    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1659        provided in case anyone wants to the the POSIX interface with UTF-8
1660        strings.
1661    
1662    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1663        C++ linking (needed for some HP-UX environments).
1664    
1665    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1666        (unused parameter) and in the pcre_printint() function (omitted "default"
1667        switch label when the default is to do nothing).
1668    
1669    15. Added some code to make it possible, when PCRE is compiled as a C++
1670        library, to replace subject pointers for pcre_exec() with a smart pointer
1671        class, thus making it possible to process discontinuous strings.
1672    
1673    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1674        much the same function. They were added by different people who were trying
1675        to make PCRE easy to compile on non-Unix systems. It has been suggested
1676        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1677        for compiling on Windows systems. I have therefore replaced it with
1678        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1679        defaults to "extern" for C or "extern C" for C++, which works fine on
1680        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1681        SCOPE with something explicit in config.h. In addition:
1682    
1683        (a) pcreposix.h still had just "extern" instead of either of these macros;
1684            I have replaced it with PCRE_DATA_SCOPE.
1685    
1686        (b) Functions such as _pcre_xclass(), which are internal to the library,
1687            but external in the C sense, all had PCRE_EXPORT in their definitions.
1688            This is apparently wrong for the Windows case, so I have removed it.
1689            (It makes no difference on Unix-like systems.)
1690    
1691    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1692        of recursive calls to match(). This is different to MATCH_LIMIT because
1693        that limits the total number of calls to match(), not all of which increase
1694        the depth of recursion. Limiting the recursion depth limits the amount of
1695        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1696        when PCRE is compiled, and changed at run time. A patch from Google adds
1697        this functionality to the C++ interface.
1698    
1699    18. Changes to the handling of Unicode character properties:
1700    
1701        (a) Updated the table to Unicode 4.1.0.
1702    
1703        (b) Recognize characters that are not in the table as "Cn" (undefined).
1704    
1705        (c) I revised the way the table is implemented to a much improved format
1706            which includes recognition of ranges. It now supports the ranges that
1707            are defined in UnicodeData.txt, and it also amalgamates other
1708            characters into ranges. This has reduced the number of entries in the
1709            table from around 16,000 to around 3,000, thus reducing its size
1710            considerably. I realized I did not need to use a tree structure after
1711            all - a binary chop search is just as efficient. Having reduced the
1712            number of entries, I extended their size from 6 bytes to 8 bytes to
1713            allow for more data.
1714    
1715        (d) Added support for Unicode script names via properties such as \p{Han}.
1716    
1717    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1718        matching that character.
1719    
1720    20. When matching a repeated Unicode property with a minimum greater than zero,
1721        (for example \pL{2,}), PCRE could look past the end of the subject if it
1722        reached it while seeking the minimum number of characters. This could
1723        happen only if some of the characters were more than one byte long, because
1724        there is a check for at least the minimum number of bytes.
1725    
1726    21. Refactored the implementation of \p and \P so as to be more general, to
1727        allow for more different types of property in future. This has changed the
1728        compiled form incompatibly. Anybody with saved compiled patterns that use
1729        \p or \P will have to recompile them.
1730    
1731    22. Added "Any" and "L&" to the supported property types.
1732    
1733    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1734        but give a compile time error if the value is greater than 0xff.
1735    
1736    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1737        accidentally not being installed or uninstalled.
1738    
1739    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1740        made were to insert the current release number. This seemed silly, because
1741        it made things harder for people building PCRE on systems that don't run
1742        "configure". I have turned pcre.h into a distributed file, no longer built
1743        by "configure", with the version identification directly included. There is
1744        no longer a pcre.h.in file.
1745    
1746        However, this change necessitated a change to the pcre-config script as
1747        well. It is built from pcre-config.in, and one of the substitutions was the
1748        release number. I have updated configure.ac so that ./configure now finds
1749        the release number by grepping pcre.h.
1750    
1751    26. Added the ability to run the tests under valgrind.
1752    
1753    
1754    Version 6.4 05-Sep-05
1755    ---------------------
1756    
1757     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1758        "--" to be printed when multiple files were scanned, even when none of the
1759        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1760        consider it to be a bug, and have restored the previous behaviour.
1761    
1762     2. A couple of code tidies to get rid of compiler warnings.
1763    
1764     3. The pcretest program used to cheat by referring to symbols in the library
1765        whose names begin with _pcre_. These are internal symbols that are not
1766        really supposed to be visible externally, and in some environments it is
1767        possible to suppress them. The cheating is now confined to including
1768        certain files from the library's source, which is a bit cleaner.
1769    
1770     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1771        file's purpose clearer.
1772    
1773     5. Reorganized pcre_ucp_findchar().
1774    
1775    
1776    Version 6.3 15-Aug-05
1777    ---------------------
1778    
1779     1. The file libpcre.pc.in did not have general read permission in the tarball.
1780    
1781     2. There were some problems when building without C++ support:
1782    
1783        (a) If C++ support was not built, "make install" and "make test" still
1784            tried to test it.
1785    
1786        (b) There were problems when the value of CXX was explicitly set. Some
1787            changes have been made to try to fix these, and ...
1788    
1789        (c) --disable-cpp can now be used to explicitly disable C++ support.
1790    
1791        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1792            backslash in a target when C++ was disabled. This confuses some
1793            versions of "make", apparently. Using an intermediate variable solves
1794            this. (Same for CPP_LOBJ.)
1795    
1796     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1797        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1798        necessary on certain architectures.
1799    
1800     4. Added a setting of -export-symbols-regex to the link command to remove
1801        those symbols that are exported in the C sense, but actually are local
1802        within the library, and not documented. Their names all begin with
1803        "_pcre_". This is not a perfect job, because (a) we have to except some
1804        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1805        available (and never for static libraries). I have made a note to try to
1806        find a way round (a) in the future.
1807    
1808    
1809    Version 6.2 01-Aug-05
1810    ---------------------
1811    
1812     1. There was no test for integer overflow of quantifier values. A construction
1813        such as {1111111111111111} would give undefined results. What is worse, if
1814        a minimum quantifier for a parenthesized subpattern overflowed and became
1815        negative, the calculation of the memory size went wrong. This could have
1816        led to memory overwriting.
1817    
1818     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1819    
1820     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1821        operating environments where this matters.
1822    
1823     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1824        PCRE options from within the C++ wrapper.
1825    
1826     5. Named capturing subpatterns were not being correctly counted when a pattern
1827        was compiled. This caused two problems: (a) If there were more than 100
1828        such subpatterns, the calculation of the memory needed for the whole
1829        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1830        back references of the form \12, where the number was greater than 9, were
1831        not recognized as back references, even though there were sufficient
1832        previous subpatterns.
1833    
1834     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1835        versions of gcc, e.g. 2.95.4.
1836    
1837    
1838    Version 6.1 21-Jun-05
1839    ---------------------
1840    
1841     1. There was one reference to the variable "posix" in pcretest.c that was not
1842        surrounded by "#if !defined NOPOSIX".
1843    
1844     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1845        the cross-check on the old pcre_info() function, for the benefit of the
1846        cut-down version of PCRE that is currently imported into Exim.
1847    
1848     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1849        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1850        patterns that start (?i) but I don't think that matters. The use of (?i) is
1851        just an example; this all applies to the other options as well.
1852    
1853     4. Since libtool seems to echo the compile commands it is issuing, the output
1854        from "make" can be reduced a bit by putting "@" in front of each libtool
1855        compile command.
1856    
1857     5. Patch from the folks at Google for configure.in to be a bit more thorough
1858        in checking for a suitable C++ installation before trying to compile the
1859        C++ stuff. This should fix a reported problem when a compiler was present,
1860        but no suitable headers.
1861    
1862     6. The man pages all had just "PCRE" as their title. I have changed them to
1863        be the relevant file name. I have also arranged that these names are
1864        retained in the file doc/pcre.txt, which is a concatenation in text format
1865        of all the man pages except the little individual ones for each function.
1866    
1867     7. The NON-UNIX-USE file had not been updated for the different set of source
1868        files that come with release 6. I also added a few comments about the C++
1869        wrapper.
1870    
1871    
1872    Version 6.0 07-Jun-05
1873    ---------------------
1874    
1875     1. Some minor internal re-organization to help with my DFA experiments.
1876    
1877     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1878        didn't matter for the library itself when fully configured, but did matter
1879        when compiling without UCP support, or within Exim, where the ucp files are
1880        not imported.
1881    
1882     3. Refactoring of the library code to split up the various functions into
1883        different source modules. The addition of the new DFA matching code (see
1884        below) to a single monolithic source would have made it really too
1885        unwieldy, quite apart from causing all the code to be include in a
1886        statically linked application, when only some functions are used. This is
1887        relevant even without the DFA addition now that patterns can be compiled in
1888        one application and matched in another.
1889    
1890        The downside of splitting up is that there have to be some external
1891        functions and data tables that are used internally in different modules of
1892        the library but which are not part of the API. These have all had their
1893        names changed to start with "_pcre_" so that they are unlikely to clash
1894        with other external names.
1895    
1896     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1897        a different (DFA) algorithm. Although it is slower than the original
1898        function, it does have some advantages for certain types of matching
1899        problem.
1900    
1901     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1902        including restarting after a partial match.
1903    
1904     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1905        defined when compiling for Windows was sent to me. I have put it into the
1906        code, though I have no means of testing or verifying it.
1907    
1908     7. Added the pcre_refcount() auxiliary function.
1909    
1910     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1911        match before or at the first newline in the subject string. In pcretest,
1912        the /f option on a pattern can be used to set this.
1913    
1914     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1915        would behave wrongly. This has been present in PCRE since release 4.0.
1916    
1917    10. A number of changes to the pcregrep command:
1918    
1919        (a) Refactored how -x works; insert ^(...)$ instead of setting
1920            PCRE_ANCHORED and checking the length, in preparation for adding
1921            something similar for -w.
1922    
1923        (b) Added the -w (match as a word) option.
1924    
1925        (c) Refactored the way lines are read and buffered so as to have more
1926            than one at a time available.
1927    
1928        (d) Implemented a pcregrep test script.
1929    
1930        (e) Added the -M (multiline match) option. This allows patterns to match
1931            over several lines of the subject. The buffering ensures that at least
1932            8K, or the rest of the document (whichever is the shorter) is available
1933            for matching (and similarly the previous 8K for lookbehind assertions).
1934    
1935        (f) Changed the --help output so that it now says
1936    
1937              -w, --word-regex(p)
1938    
1939            instead of two lines, one with "regex" and the other with "regexp"
1940            because that confused at least one person since the short forms are the
1941            same. (This required a bit of code, as the output is generated
1942            automatically from a table. It wasn't just a text change.)
1943    
1944        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1945            option but starts with a hyphen. Could be a pattern or a path name
1946            starting with a hyphen, for instance.
1947    
1948        (h) "-" can be given as a file name to represent stdin.
1949    
1950        (i) When file names are being printed, "(standard input)" is used for
1951            the standard input, for compatibility with GNU grep. Previously
1952            "<stdin>" was used.
1953    
1954        (j) The option --label=xxx can be used to supply a name to be used for
1955            stdin when file names are being printed. There is no short form.
1956    
1957        (k) Re-factored the options decoding logic because we are going to add
1958            two more options that take data. Such options can now be given in four
1959            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1960    
1961        (l) Added the -A, -B, and -C options for requesting that lines of context
1962            around matches be printed.
1963    
1964        (m) Added the -L option to print the names of files that do not contain
1965            any matching lines, that is, the complement of -l.
1966    
1967        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1968            continue to scan other files.
1969    
1970        (o) The -s option was incorrectly implemented. For compatibility with other
1971            greps, it now suppresses the error message for a non-existent or non-
1972            accessible file (but not the return code). There is a new option called
1973            -q that suppresses the output of matching lines, which was what -s was
1974            previously doing.
1975    
1976        (p) Added --include and --exclude options to specify files for inclusion
1977            and exclusion when recursing.
1978    
1979    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1980        Hopefully, it now does.
1981    
1982    12. Missing cast in pcre_study().
1983    
1984    13. Added an "uninstall" target to the makefile.
1985    
1986    14. Replaced "extern" in the function prototypes in Makefile.in with
1987        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1988        world, but is set differently for Windows.
1989    
1990    15. Added a second compiling function called pcre_compile2(). The only
1991        difference is that it has an extra argument, which is a pointer to an
1992        integer error code. When there is a compile-time failure, this is set
1993        non-zero, in addition to the error test pointer being set to point to an
1994        error message. The new argument may be NULL if no error number is required
1995        (but then you may as well call pcre_compile(), which is now just a
1996        wrapper). This facility is provided because some applications need a
1997        numeric error indication, but it has also enabled me to tidy up the way
1998        compile-time errors are handled in the POSIX wrapper.
1999    
2000    16. Added VPATH=.libs to the makefile; this should help when building with one
2001        prefix path and installing with another. (Or so I'm told by someone who
2002        knows more about this stuff than I do.)
2003    
2004    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2005        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2006        match everything, including newlines. This is not POSIX-compatible, but
2007        somebody wanted the feature. From pcretest it can be activated by using
2008        both the P and the s flags.
2009    
2010    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2011    
2012    19. libpcre.pc was being incorrectly installed as executable.
2013    
2014    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2015        it now also looks for '\r' so that it will work unmodified on Windows.
2016    
2017    21. Added Google's contributed C++ wrapper to the distribution.
2018    
2019    22. Added some untidy missing memory free() calls in pcretest, to keep
2020        Electric Fence happy when testing.
2021    
2022    
2023    
2024    Version 5.0 13-Sep-04
2025    ---------------------
2026    
2027     1. Internal change: literal characters are no longer packed up into items
2028        containing multiple characters in a single byte-string. Each character
2029        is now matched using a separate opcode. However, there may be more than one
2030        byte in the character in UTF-8 mode.
2031    
2032     2. The pcre_callout_block structure has two new fields: pattern_position and
2033        next_item_length. These contain the offset in the pattern to the next match
2034        item, and its length, respectively.
2035    
2036     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2037        insertion of callouts before each pattern item. Added the /C option to
2038        pcretest to make use of this.
2039    
2040     4. On the advice of a Windows user, the lines
2041    
2042          #if defined(_WIN32) || defined(WIN32)
2043          _setmode( _fileno( stdout ), 0x8000 );
2044          #endif  /* defined(_WIN32) || defined(WIN32) */
2045    
2046        have been added to the source of pcretest. This apparently does useful
2047        magic in relation to line terminators.
2048    
2049     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2050        for the benefit of those environments where the "b" makes a difference.
2051    
2052     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2053        to know about it. I have put a hack into configure.in that adds in code
2054        to set GCC=yes if CC=icc. This seems to end up at a point in the
2055        generated configure script that is early enough to affect the setting of
2056        compiler options, which is what is needed, but I have no means of testing
2057        whether it really works. (The user who reported this had patched the
2058        generated configure script, which of course I cannot do.)
2059    
2060        LATER: After change 22 below (new libtool files), the configure script
2061        seems to know about icc (and also ecc). Therefore, I have commented out
2062        this hack in configure.in.
2063    
2064     7. Added support for pkg-config (2 patches were sent in).
2065    
2066     8. Negated POSIX character classes that used a combination of internal tables
2067        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2068        [[:^ascii]]. Typically, they would match almost any characters. The other
2069        POSIX classes were not broken in this way.
2070    
2071     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2072        to find the match, as PCRE was deluded into thinking that the match had to
2073        start at the start point or following a newline. The same bug applied to
2074        patterns with negative forward assertions or any backward assertions
2075        preceding ".*" at the start, unless the pattern required a fixed first
2076        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2077    
2078    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2079        starting at the last subject character, bytes beyond the end of the subject
2080        string were read.
2081    
2082    11. Renamed the variable "class" as "classbits" to make life easier for C++
2083        users. (Previously there was a macro definition, but it apparently wasn't
2084        enough.)
2085    
2086    12. Added the new field "tables" to the extra data so that tables can be passed
2087        in at exec time, or the internal tables can be re-selected. This allows
2088        a compiled regex to be saved and re-used at a later time by a different
2089        program that might have everything at different addresses.
2090    
2091    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2092        -R library as well as a -L library.
2093    
2094    14. The debugging options of pcretest (-d on the command line or D on a
2095        pattern) showed incorrect output for anything following an extended class
2096        that contained multibyte characters and which was followed by a quantifier.
2097    
2098    15. Added optional support for general category Unicode character properties
2099        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2100        support. It adds about 90K to the size of the library. The meanings of the
2101        inbuilt class escapes such as \d and \s have NOT been changed.
2102    
2103    16. Updated pcredemo.c to include calls to free() to release the memory for the
2104        compiled pattern.
2105    
2106    17. The generated file chartables.c was being created in the source directory
2107        instead of in the building directory. This caused the build to fail if the
2108        source directory was different from the building directory, and was
2109        read-only.
2110    
2111    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2112        file. No doubt somebody will tell me if they don't make sense... Also added
2113        Dan Mooney's comments about building on OpenVMS.
2114    
2115    19. Added support for partial matching via the PCRE_PARTIAL option for
2116        pcre_exec() and the \P data escape in pcretest.
2117    
2118    20. Extended pcretest with 3 new pattern features:
2119    
2120        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2121              write the compiled pattern to the file whose name is "rest-of-line".
2122              This is a straight binary dump of the data, with the saved pointer to
2123              the character tables forced to be NULL. The study data, if any, is
2124              written too. After writing, pcretest reads a new pattern.
2125    
2126        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2127              compiled pattern from the given file. There must not be any
2128              occurrences of "<" in the file name (pretty unlikely); if there are,
2129              pcretest will instead treat the initial "<" as a pattern delimiter.
2130              After reading in the pattern, pcretest goes on to read data lines as
2131              usual.
2132    
2133        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2134              and 16-bit fields in a compiled pattern, to simulate a pattern that
2135              was compiled on a host of opposite endianness.
2136    
2137    21. The pcre-exec() function can now cope with patterns that were compiled on
2138        hosts of opposite endianness, with this restriction:
2139    
2140          As for any compiled expression that is saved and used later, the tables
2141          pointer field cannot be preserved; the extra_data field in the arguments
2142          to pcre_exec() should be used to pass in a tables address if a value
2143          other than the default internal tables were used at compile time.
2144    
2145    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2146        now diagnosed as an error. Previously, most of the time, a negative number
2147        would have been treated as zero, but if in addition "ovector" was passed as
2148        NULL, a crash could occur.
2149    
2150    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2151        new versions from the libtool 1.5 distribution (the last one is a copy of
2152        a file called libtool.m4). This seems to have fixed the need to patch
2153        "configure" to support Darwin 1.3 (which I used to do). However, I still
2154        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2155        workstation).
2156    
2157    24. Changed the PCRE licence to be the more standard "BSD" licence.
2158    
2159    
2160    Version 4.5 01-Dec-03
2161    ---------------------
2162    
2163     1. There has been some re-arrangement of the code for the match() function so
2164        that it can be compiled in a version that does not call itself recursively.
2165        Instead, it keeps those local variables that need separate instances for
2166        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2167        needs to "recurse". Keeping track of where control must go is done by means
2168        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2169        hide most of the details from the main code, and operates only if
2170        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2171        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2172        operating.
2173    
2174        To make it easier for callers to provide specially tailored get/free
2175        functions for this usage, two new functions, pcre_stack_malloc, and
2176        pcre_stack_free, are used. They are always called in strict stacking order,
2177        and the size of block requested is always the same.
2178    
2179        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2180        PCRE has been compiled to use the stack or the heap for recursion. The
2181        -C option of pcretest uses this to show which version is compiled.
2182    
2183        A new data escape \S, is added to pcretest; it causes the amounts of store
2184        obtained and freed by both kinds of malloc/free at match time to be added
2185        to the output.
2186    
2187     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2188        what's available on my current Linux desktop machine.
2189    
2190     3. When matching a UTF-8 string, the test for a valid string at the start has
2191        been extended. If start_offset is not zero, PCRE now checks that it points
2192        to a byte that is the start of a UTF-8 character. If not, it returns
2193        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2194        this is necessary because there may be backward assertions in the pattern.
2195        When matching the same subject several times, it may save resources to use
2196        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2197    
2198     4. The code for checking the validity of UTF-8 strings has been tightened so
2199        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2200        containing "overlong sequences".
2201    
2202     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2203        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2204        should have been "&", but it just so happened that all the cases this let
2205        through by mistake were picked up later in the function.
2206    
2207     6. I had used a variable called "isblank" - this is a C99 function, causing
2208        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2209    
2210     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2211        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2212        so the version is shown; (c) stop "make test" echoing "./RunTest".
2213    
2214     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2215    
2216     9. The prototype for memmove() for systems that don't have it was using
2217        size_t, but the inclusion of the header that defines size_t was later. I've
2218        moved the #includes for the C headers earlier to avoid this.
2219    
2220    10. Added some adjustments to the code to make it easier to compiler on certain
2221        special systems:
2222    
2223          (a) Some "const" qualifiers were missing.
2224          (b) Added the macro EXPORT before all exported functions; by default this
2225              is defined to be empty.
2226          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2227              that it reads its output file name as an argument instead of writing
2228              to the standard output and assuming this can be redirected.
2229    
2230    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2231        class containing characters with values greater than 255, PCRE compilation
2232        went into a loop.
2233    
2234    12. A recursive reference to a subpattern that was within another subpattern
2235        that had a minimum quantifier of zero caused PCRE to crash. For example,
2236        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2237        recursion. If the recursively-called subpattern itself had a zero repeat,
2238        that was OK.
2239    
2240    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2241        buffer into which it was copied (for escape processing) was still set at
2242        1024, so long lines caused crashes.
2243    
2244    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2245        "internal error: code overflow...". This applied to any character class
2246        that was followed by a possessive quantifier.
2247    
2248    15. Modified the Makefile to add libpcre.la as a prerequisite for
2249        libpcreposix.la because I was told this is needed for a parallel build to
2250        work.
2251    
2252    16. If a pattern that contained .* following optional items at the start was
2253        studied, the wrong optimizing data was generated, leading to matching
2254        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2255        matching string must start with a or b or c. The correct conclusion for
2256        this pattern is that a match can start with any character.
2257    
2258    
2259    Version 4.4 13-Aug-03
2260    ---------------------
2261    
2262     1. In UTF-8 mode, a character class containing characters with values between
2263        127 and 255 was not handled correctly if the compiled pattern was studied.
2264        In fixing this, I have also improved the studying algorithm for such
2265        classes (slightly).
2266    
2267     2. Three internal functions had redundant arguments passed to them. Removal
2268        might give a very teeny performance improvement.
2269    
2270     3. Documentation bug: the value of the capture_top field in a callout is *one
2271        more than* the number of the hightest numbered captured substring.
2272    
2273     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2274        in incorrectly linking with a previously installed version. They now link
2275        explicitly with libpcre.la.
2276    
2277     5. configure.in no longer needs to recognize Cygwin specially.
2278    
2279     6. A problem in pcre.in for Windows platforms is fixed.
2280    
2281     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2282        pcretest, it used to include the size of the study block as part of its
2283        output. Unfortunately, the structure contains a field that has a different
2284        size on different hardware architectures. This meant that the tests that
2285        showed this size failed. As the block is currently always of a fixed size,
2286        this information isn't actually particularly useful in pcretest output, so
2287        I have just removed it.
2288    
2289     8. Three pre-processor statements accidentally did not start in column 1.
2290        Sadly, there are *still* compilers around that complain, even though
2291        standard C has not required this for well over a decade. Sigh.
2292    
2293     9. In pcretest, the code for checking callouts passed small integers in the
2294        callout_data field, which is a void * field. However, some picky compilers
2295        complained about the casts involved for this on 64-bit systems. Now
2296        pcretest passes the address of the small integer instead, which should get
2297        rid of the warnings.
2298    
2299    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2300        both compile and run time, and gives an error if an invalid UTF-8 sequence
2301        is found. There is a option for disabling this check in cases where the
2302        string is known to be correct and/or the maximum performance is wanted.
2303    
2304    11. In response to a bug report, I changed one line in Makefile.in from
2305    
2306            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2307        to
2308            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2309    
2310        to look similar to other lines, but I have no way of telling whether this
2311        is the right thing to do, as I do not use Windows. No doubt I'll get told
2312        if it's wrong...
2313    
2314    
2315    Version 4.3 21-May-03
2316    ---------------------
2317    
2318    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2319       Makefile.
2320    
2321    2. Some refactoring to improve the quality of the code:
2322    
2323       (i)   The utf8_table... variables are now declared "const".
2324    
2325       (ii)  The code for \cx, which used the "case flipping" table to upper case
2326             lower case letters, now just substracts 32. This is ASCII-specific,
2327             but the whole concept of \cx is ASCII-specific, so it seems
2328             reasonable.
2329    
2330       (iii) PCRE was using its character types table to recognize decimal and
2331             hexadecimal digits in the pattern. This is silly, because it handles
2332             only 0-9, a-f, and A-F, but the character types table is locale-
2333             specific, which means strange things might happen. A private
2334             table is now used for this - though it costs 256 bytes, a table is
2335             much faster than multiple explicit tests. Of course, the standard
2336             character types table is still used for matching digits in subject
2337             strings against \d.
2338    
2339       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2340             ending in _t are). So I've renamed it as ESC_tee.
2341    
2342    3. The first argument for regexec() in the POSIX wrapper should have been
2343       defined as "const".
2344    
2345    4. Changed pcretest to use malloc() for its buffers so that they can be
2346       Electric Fenced for debugging.
2347    
2348    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2349       to read one or more bytes before the start of the subject string. Often this
2350       had no effect on PCRE's behaviour, but in some circumstances it could
2351       provoke a segmentation fault.
2352    
2353    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2354       to try to read one or more bytes before the start of the subject string.
2355    
2356    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2357       UTF-8 support could misbehave in various ways if the subject string
2358       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2359       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2360       back over UTF-8 characters.)
2361    
2362    
2363    Version 4.2 14-Apr-03
2364    ---------------------
2365    
2366    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2367    
2368    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2369         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2370         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2371         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2372         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2373           and BUILD_EXEEXT
2374         Note: automatic setting of the BUILD variables is not yet working
2375         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2376           compile-time but not at link-time
2377         [LINK]: use for linking executables only
2378         make different versions for Windows and non-Windows
2379         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2380           libraries
2381         [LINK_FOR_BUILD]: new variable
2382         [OBJEXT]: use throughout
2383         [EXEEXT]: use throughout
2384         <winshared>: new target
2385         <wininstall>: new target
2386         <dftables.o>: use native compiler
2387         <dftables>: use native linker
2388         <install>: handle Windows platform correctly
2389         <clean>: ditto
2390         <check>: ditto
2391         copy DLL to top builddir before testing
2392    
2393       As part of these changes, -no-undefined was removed again. This was reported
2394       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2395       in any case.
2396    
2397    3. Some tidies to get rid of compiler warnings:
2398    
2399       . In the match_data structure, match_limit was an unsigned long int, whereas
2400         match_call_count was an int. I've made them both unsigned long ints.
2401    
2402       . In pcretest the fact that a const uschar * doesn't automatically cast to
2403         a void * provoked a warning.
2404    
2405       . Turning on some more compiler warnings threw up some "shadow" variables
2406         and a few more missing casts.
2407    
2408    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2409       option, a class that contained a single character with a value between 128
2410       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2411    
2412    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2413       option, a class that contained several characters, but with at least one
2414       whose value was between 128 and 255 caused PCRE to crash.
2415    
2416    
2417  Version 4.1 12-Mar-03  Version 4.1 12-Mar-03
2418  ---------------------  ---------------------
2419    

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