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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 426 by ph10, Wed Aug 26 15:38:32 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8        was out-of-date, and there was no check on the pcre_compile() error code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. Chaos could result.
47    
48    9.  The restrictions on what a pattern can contain when partial matching is
49        requested for pcre_exec() have been removed. All patterns can now be
50        partially matched by this function. In addition, if there are at least two
51        slots in the offset vector, the offsets of the first-encountered partial
52        match are set in them when PCRE_ERROR_PARTIAL is returned.
53    
54    
55    Version 7.9 11-Apr-09
56    ---------------------
57    
58    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
59        (pcretest), all targets were linked against these libraries. This included
60        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
61        libraries. This caused unwanted dependencies to be created. This problem
62        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
63        pcretest is linked with readline.
64    
65    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
66        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
67        moved outside it again, because FALSE and TRUE are already defined in AIX,
68        but BOOL is not.
69    
70    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
71        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
72    
73    4.  The pcregrep documentation said spaces were inserted as well as colons (or
74        hyphens) following file names and line numbers when outputting matching
75        lines. This is not true; no spaces are inserted. I have also clarified the
76        wording for the --colour (or --color) option.
77    
78    5.  In pcregrep, when --colour was used with -o, the list of matching strings
79        was not coloured; this is different to GNU grep, so I have changed it to be
80        the same.
81    
82    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
83        each matching line was coloured. Now it goes on to look for further matches
84        of any of the test patterns, which is the same behaviour as GNU grep.
85    
86    7.  A pattern that could match an empty string could cause pcregrep to loop; it
87        doesn't make sense to accept an empty string match in pcregrep, so I have
88        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
89        seems to be how GNU grep behaves.
90    
91    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
92        start or after a newline", because the conditional assertion was not being
93        correctly handled. The rule now is that both the assertion and what follows
94        in the first alternative must satisfy the test.
95    
96    9.  If auto-callout was enabled in a pattern with a conditional group whose
97        condition was an assertion, PCRE could crash during matching, both with
98        pcre_exec() and pcre_dfa_exec().
99    
100    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
101        used for matching.
102    
103    11. Unicode property support in character classes was not working for
104        characters (bytes) greater than 127 when not in UTF-8 mode.
105    
106    12. Added the -M command line option to pcretest.
107    
108    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
109    
110    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
111    
112    16. Added comments and documentation about mis-use of no_arg in the C++
113        wrapper.
114    
115    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
116        from Martin Jerabek that uses macro names for all relevant character and
117        string constants.
118    
119    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
120        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
121        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
122        these, but not everybody uses configure.
123    
124    19. A conditional group that had only one branch was not being correctly
125        recognized as an item that could match an empty string. This meant that an
126        enclosing group might also not be so recognized, causing infinite looping
127        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
128        with the subject "ab", where knowledge that the repeated group can match
129        nothing is needed in order to break the loop.
130    
131    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
132        exec(), but without supplying a callout function, matching went wrong.
133    
134    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
135        leak if the size of the offset vector was greater than 30. When the vector
136        is smaller, the saved offsets during recursion go onto a local stack
137        vector, but for larger vectors malloc() is used. It was failing to free
138        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
139        error, in fact).
140    
141    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
142        heapframe that is used only when UTF-8 support is enabled. This caused no
143        problem, but was untidy.
144    
145    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
146        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
147        included within another project.
148    
149    24. Steven Van Ingelgem's patches to add more options to the CMake support,
150        slightly modified by me:
151    
152          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
153              not building pcregrep.
154    
155          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
156              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
157    
158    25. Forward references, both numeric and by name, in patterns that made use of
159        duplicate group numbers, could behave incorrectly or give incorrect errors,
160        because when scanning forward to find the reference group, PCRE was not
161        taking into account the duplicate group numbers. A pattern such as
162        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
163    
164    26. Changed a few more instances of "const unsigned char *" to USPTR, making
165        the feature of a custom pointer more persuasive (as requested by a user).
166    
167    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
168        pcretest.c, inside #ifndefs, because it seems they are sometimes already
169        pre-defined.
170    
171    28. Added support for (*UTF8) at the start of a pattern.
172    
173    29. Arrange for flags added by the "release type" setting in CMake to be shown
174        in the configuration summary.
175    
176    
177    Version 7.8 05-Sep-08
178    ---------------------
179    
180    1.  Replaced UCP searching code with optimized version as implemented for Ad
181        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
182        stage table and inline lookup instead of a function, giving speed ups of 2
183        to 5 times on some simple patterns that I tested. Permission was given to
184        distribute the MultiStage2.py script that generates the tables (it's not in
185        the tarball, but is in the Subversion repository).
186    
187    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
188        scripts.
189    
190    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
191        a group with a zero qualifier. The result of the study could be incorrect,
192        or the function might crash, depending on the pattern.
193    
194    4.  Caseless matching was not working for non-ASCII characters in back
195        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
196        It now works when Unicode Property Support is available.
197    
198    5.  In pcretest, an escape such as \x{de} in the data was always generating
199        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
200        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
201        truncation.
202    
203    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
204    
205    7.  Added two (int) casts to pcregrep when printing the difference of two
206        pointers, in case they are 64-bit values.
207    
208    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
209        test 2 if it fails.
210    
211    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
212        and a #define of that name to empty if it is not externally set. This is to
213        allow users of MSVC to set it if necessary.
214    
215    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
216        the convenience functions in the pcre_get.c source file.
217    
218    11. An option change at the start of a pattern that had top-level alternatives
219        could cause overwriting and/or a crash. This command provoked a crash in
220        some environments:
221    
222          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
223    
224        This potential security problem was recorded as CVE-2008-2371.
225    
226    12. For a pattern where the match had to start at the beginning or immediately
227        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
228        pcre_dfa_exec() could read past the end of the passed subject if there was
229        no match. To help with detecting such bugs (e.g. with valgrind), I modified
230        pcretest so that it places the subject at the end of its malloc-ed buffer.
231    
232    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
233        exec() might read past the end of the data buffer in UTF-8 mode.
234    
235    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
236        the data contained the byte 0x85 as part of a UTF-8 character within its
237        first line. This applied both to normal and DFA matching.
238    
239    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
240        /^[^d]*?$/8 failed to match "abc".
241    
242    16. Added a missing copyright notice to pcrecpp_internal.h.
243    
244    17. Make it more clear in the documentation that values returned from
245        pcre_exec() in ovector are byte offsets, not character counts.
246    
247    18. Tidied a few places to stop certain compilers from issuing warnings.
248    
249    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
250        supplied by Stefan Weber. I made a further small update for 7.8 because
251        there is a change of source arrangements: the pcre_searchfuncs.c module is
252        replaced by pcre_ucd.c.
253    
254    
255    Version 7.7 07-May-08
256    ---------------------
257    
258    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
259        a string to a long long, pretend we don't even have a long long." This is
260        done by checking for the strtoq, strtoll, and _strtoi64 functions.
261    
262    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
263        pre-7.6 versions, which defined a global no_arg variable instead of putting
264        it in the RE class. (See also #8 below.)
265    
266    3.  Remove a line of dead code, identified by coverity and reported by Nuno
267        Lopes.
268    
269    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
270    
271        (1) The include/exclude patterns were being applied to the whole pathnames
272            of files, instead of just to the final components.
273    
274        (2) If there was more than one level of directory, the subdirectories were
275            skipped unless they satisfied the include/exclude conditions. This is
276            inconsistent with GNU grep (and could even be seen as contrary to the
277            pcregrep specification - which I improved to make it absolutely clear).
278            The action now is always to scan all levels of directory, and just
279            apply the include/exclude patterns to regular files.
280    
281    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
282        --exclude_dir in the tests to avoid scanning .svn directories.
283    
284    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
285        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
286        doesn't support NULs in patterns.
287    
288    7.  Added some missing "const"s to declarations of static tables in
289        pcre_compile.c and pcre_dfa_exec.c.
290    
291    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
292        caused by fix #2  above. (Subsequently also a second patch to fix the
293        first patch. And a third patch - this was a messy problem.)
294    
295    9.  Applied Craig's patch to remove the use of push_back().
296    
297    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
298        matching function regexec().
299    
300    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
301        which, however, unlike Perl's \g{...}, are subroutine calls, not back
302        references. PCRE supports relative numbers with this syntax (I don't think
303        Oniguruma does).
304    
305    12. Previously, a group with a zero repeat such as (...){0} was completely
306        omitted from the compiled regex. However, this means that if the group
307        was called as a subroutine from elsewhere in the pattern, things went wrong
308        (an internal error was given). Such groups are now left in the compiled
309        pattern, with a new opcode that causes them to be skipped at execution
310        time.
311    
312    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
313        to the way PCRE behaves:
314    
315        (a) A lone ] character is dis-allowed (Perl treats it as data).
316    
317        (b) A back reference to an unmatched subpattern matches an empty string
318            (Perl fails the current match path).
319    
320        (c) A data ] in a character class must be notated as \] because if the
321            first data character in a class is ], it defines an empty class. (In
322            Perl it is not possible to have an empty class.) The empty class []
323            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
324            The negative empty class [^] matches any one character, independently
325            of the DOTALL setting.
326    
327    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
328        non-existent subpattern following a character class starting with ']' and
329        containing () gave an internal compiling error instead of "reference to
330        non-existent subpattern". Fortunately, when the pattern did exist, the
331        compiled code was correct. (When scanning forwards to check for the
332        existencd of the subpattern, it was treating the data ']' as terminating
333        the class, so got the count wrong. When actually compiling, the reference
334        was subsequently set up correctly.)
335    
336    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
337        it was being rejected as not supported by pcre_dfa_exec(), even though
338        other assertions are supported. I have made pcre_dfa_exec() support
339        (*FAIL).
340    
341    16. The implementation of 13c above involved the invention of a new opcode,
342        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
343        cannot be changed at match time, I realized I could make a small
344        improvement to matching performance by compiling OP_ALLANY instead of
345        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
346        on the OP_ANY path.
347    
348    17. Compiling pcretest on Windows with readline support failed without the
349        following two fixes: (1) Make the unistd.h include conditional on
350        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
351    
352    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
353        ncurses library to be included for pcretest when ReadLine support is
354        requested, but also to allow for it to be overridden. This patch came from
355        Daniel Bergström.
356    
357    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
358        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
359        any errors with the current Unicode tables. Thanks to Peter Kankowski for
360        spotting this.
361    
362    
363    Version 7.6 28-Jan-08
364    ---------------------
365    
366    1.  A character class containing a very large number of characters with
367        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
368        overflow.
369    
370    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
371        HAVE_LONG_LONG is not defined.
372    
373    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
374        bring them up to date and include new features. This patch includes:
375    
376        - Fixed PH's badly added libz and libbz2 support.
377        - Fixed a problem with static linking.
378        - Added pcredemo. [But later removed - see 7 below.]
379        - Fixed dftables problem and added an option.
380        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
381            HAVE_LONG_LONG.
382        - Added readline support for pcretest.
383        - Added an listing of the option settings after cmake has run.
384    
385    4.  A user submitted a patch to Makefile that makes it easy to create
386        "pcre.dll" under mingw when using Configure/Make. I added stuff to
387        Makefile.am that cause it to include this special target, without
388        affecting anything else. Note that the same mingw target plus all
389        the other distribution libraries and programs are now supported
390        when configuring with CMake (see 6 below) instead of with
391        Configure/Make.
392    
393    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
394        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
395        exported in the Windows port". It has not yet been confirmed that the patch
396        solves the problem, but it does no harm.
397    
398    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
399        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
400        with CMake, and also correct the comment about stack recursion.
401    
402    7.  Remove the automatic building of pcredemo from the ./configure system and
403        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
404        of a program that users should build themselves after PCRE is installed, so
405        building it automatically is not really right. What is more, it gave
406        trouble in some build environments.
407    
408    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
409    
410    
411    Version 7.5 10-Jan-08
412    ---------------------
413    
414    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
415        values in parens when parsing an RE using the C++ wrapper."
416    
417    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
418        Characters greater than 255 were excluded from the class instead of being
419        included.
420    
421    3.  The same bug as (2) above applied to negated POSIX classes such as
422        [:^space:].
423    
424    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
425        defined or documented. It seems to have been a typo for PCRE_STATIC, so
426        I have changed it.
427    
428    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
429        first named subpattern) and a construct such as (?&a) would reference the
430        first named subpattern whose name started with "a" (in other words, the
431        length check was missing). Both these problems are fixed. "Subpattern name
432        expected" is now given for (?&) (a zero-length name), and this patch also
433        makes it give the same error for \k'' (previously it complained that that
434        was a reference to a non-existent subpattern).
435    
436    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
437        this is right because (?- can be followed by option settings as well as by
438        digits. I have, however, made the messages clearer.
439    
440    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
441        than the number used in the conditional) now cause a compile-time error.
442        This is actually not compatible with Perl, which accepts such patterns, but
443        treats the conditional as always being FALSE (as PCRE used to), but it
444        seems to me that giving a diagnostic is better.
445    
446    8.  Change "alphameric" to the more common word "alphanumeric" in comments
447        and messages.
448    
449    9.  Fix two occurrences of "backslash" in comments that should have been
450        "backspace".
451    
452    10. Remove two redundant lines of code that can never be obeyed (their function
453        was moved elsewhere).
454    
455    11. The program that makes PCRE's Unicode character property table had a bug
456        which caused it to generate incorrect table entries for sequences of
457        characters that have the same character type, but are in different scripts.
458        It amalgamated them into a single range, with the script of the first of
459        them. In other words, some characters were in the wrong script. There were
460        thirteen such cases, affecting characters in the following ranges:
461    
462          U+002b0 - U+002c1
463          U+0060c - U+0060d
464          U+0061e - U+00612
465          U+0064b - U+0065e
466          U+0074d - U+0076d
467          U+01800 - U+01805
468          U+01d00 - U+01d77
469          U+01d9b - U+01dbf
470          U+0200b - U+0200f
471          U+030fc - U+030fe
472          U+03260 - U+0327f
473          U+0fb46 - U+0fbb1
474          U+10450 - U+1049d
475    
476    12. The -o option (show only the matching part of a line) for pcregrep was not
477        compatible with GNU grep in that, if there was more than one match in a
478        line, it showed only the first of them. It now behaves in the same way as
479        GNU grep.
480    
481    13. If the -o and -v options were combined for pcregrep, it printed a blank
482        line for every non-matching line. GNU grep prints nothing, and pcregrep now
483        does the same. The return code can be used to tell if there were any
484        non-matching lines.
485    
486    14. Added --file-offsets and --line-offsets to pcregrep.
487    
488    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
489        infinitely looping recursion. The bug was that positive lookaheads were not
490        being skipped when checking for a possible empty match (negative lookaheads
491        and both kinds of lookbehind were skipped).
492    
493    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
494        inclusion of <windows.h> to before rather than after the definition of
495        INVALID_FILE_ATTRIBUTES (patch from David Byron).
496    
497    17. Specifying a possessive quantifier with a specific limit for a Unicode
498        character property caused pcre_compile() to compile bad code, which led at
499        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
500        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
501        caused the error; without that there was no problem.
502    
503    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
504    
505    19. Added --enable-pcretest-libreadline.
506    
507    20. In pcrecpp.cc, the variable 'count' was incremented twice in
508        RE::GlobalReplace(). As a result, the number of replacements returned was
509        double what it should be. I removed one of the increments, but Craig sent a
510        later patch that removed the other one (the right fix) and added unit tests
511        that check the return values (which was not done before).
512    
513    21. Several CMake things:
514    
515        (1) Arranged that, when cmake is used on Unix, the libraries end up with
516            the names libpcre and libpcreposix, not just pcre and pcreposix.
517    
518        (2) The above change means that pcretest and pcregrep are now correctly
519            linked with the newly-built libraries, not previously installed ones.
520    
521        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
522    
523    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
524        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
525        UTF-8 newline character). The key issue is that the pattern starts .*;
526        this means that the match must be either at the beginning, or after a
527        newline. The bug was in the code for advancing after a failed match and
528        checking that the new position followed a newline. It was not taking
529        account of UTF-8 characters correctly.
530    
531    23. PCRE was behaving differently from Perl in the way it recognized POSIX
532        character classes. PCRE was not treating the sequence [:...:] as a
533        character class unless the ... were all letters. Perl, however, seems to
534        allow any characters between [: and :], though of course it rejects as
535        unknown any "names" that contain non-letters, because all the known class
536        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
537        for example, whereas PCRE did not - it did not recognize a POSIX character
538        class. This seemed a bit dangerous, so the code has been changed to be
539        closer to Perl. The behaviour is not identical to Perl, because PCRE will
540        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
541        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
542        Perl does, and where it didn't before.
543    
544    24. Rewrite so as to remove the single use of %n from pcregrep because in some
545        Windows environments %n is disabled by default.
546    
547    
548    Version 7.4 21-Sep-07
549    ---------------------
550    
551    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
552        means that a class such as [\s] counted as "explicit reference to CR or
553        LF". That isn't really right - the whole point of the change was to try to
554        help when there was an actual mention of one of the two characters. So now
555        the change happens only if \r or \n (or a literal CR or LF) character is
556        encountered.
557    
558    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
559        of both had grown to the point where there were only 3 bits left.
560        Fortunately, there was spare space in the data structure, and so I have
561        moved the internal flags into a new 16-bit field to free up more option
562        bits.
563    
564    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
565        but did not set the internal JCHANGED flag - either of these is enough to
566        control the way the "get" function works - but the PCRE_INFO_JCHANGED
567        facility is supposed to tell if (?J) was ever used, so now (?J) at the
568        start sets both bits.
569    
570    4.  Added options (at build time, compile time, exec time) to change \R from
571        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
572    
573    5.  doc/pcresyntax.html was missing from the distribution.
574    
575    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
576        compatibility, even though it is no longer used.
577    
578    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
579        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
580        windows.h file is present (where different names are used). [This was
581        reversed later after testing - see 16 below.]
582    
583    8.  Changed all #include <config.h> to #include "config.h". There were also
584        some further <pcre.h> cases that I changed to "pcre.h".
585    
586    9.  When pcregrep was used with the --colour option, it missed the line ending
587        sequence off the lines that it output.
588    
589    10. It was pointed out to me that arrays of string pointers cause lots of
590        relocations when a shared library is dynamically loaded. A technique of
591        using a single long string with a table of offsets can drastically reduce
592        these. I have refactored PCRE in four places to do this. The result is
593        dramatic:
594    
595          Originally:                          290
596          After changing UCP table:            187
597          After changing error message table:   43
598          After changing table of "verbs"       36
599          After changing table of Posix names   22
600    
601        Thanks to the folks working on Gregex for glib for this insight.
602    
603    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
604        unicode-properties was also set.
605    
606    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
607    
608    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
609        checked only for CRLF.
610    
611    14. Added casts to pcretest.c to avoid compiler warnings.
612    
613    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
614    
615    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
616        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
617        entirely. This removes changes made in 7 above.
618    
619    17. The CMake files have been updated, and there is now more information about
620        building with CMake in the NON-UNIX-USE document.
621    
622    
623    Version 7.3 28-Aug-07
624    ---------------------
625    
626     1. In the rejigging of the build system that eventually resulted in 7.1, the
627        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
628        brackets there is not right, since it causes compilers to look for an
629        installed pcre.h, not the version that is in the source that is being
630        compiled (which of course may be different). I have changed it back to:
631    
632          #include "pcre.h"
633    
634        I have a vague recollection that the change was concerned with compiling in
635        different directories, but in the new build system, that is taken care of
636        by the VPATH setting the Makefile.
637    
638     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
639        when the subject happened to end in the byte 0x85 (e.g. if the last
640        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
641        characters but of course it shouldn't be taken as a newline when it is part
642        of another character. The bug was that, for an unlimited repeat of . in
643        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
644        characters when looking for a newline.
645    
646     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
647    
648     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
649        in debug output.
650    
651     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
652        long printing in the pcrecpp unittest when running under MinGW.
653    
654     6. ESC_K was left out of the EBCDIC table.
655    
656     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
657        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
658        limit also applies to "virtual nesting" when a pattern is recursive, and in
659        this case 1000 isn't so big. I have been able to remove this limit at the
660        expense of backing off one optimization in certain circumstances. Normally,
661        when pcre_exec() would call its internal match() function recursively and
662        immediately return the result unconditionally, it uses a "tail recursion"
663        feature to save stack. However, when a subpattern that can match an empty
664        string has an unlimited repetition quantifier, it no longer makes this
665        optimization. That gives it a stack frame in which to save the data for
666        checking that an empty string has been matched. Previously this was taken
667        from the 1000-entry workspace that had been reserved. So now there is no
668        explicit limit, but more stack is used.
669    
670     8. Applied Daniel's patches to solve problems with the import/export magic
671        syntax that is required for Windows, and which was going wrong for the
672        pcreposix and pcrecpp parts of the library. These were overlooked when this
673        problem was solved for the main library.
674    
675     9. There were some crude static tests to avoid integer overflow when computing
676        the size of patterns that contain repeated groups with explicit upper
677        limits. As the maximum quantifier is 65535, the maximum group length was
678        set at 30,000 so that the product of these two numbers did not overflow a
679        32-bit integer. However, it turns out that people want to use groups that
680        are longer than 30,000 bytes (though not repeat them that many times).
681        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
682        made it possible to implement the integer overflow checks in a much more
683        dynamic way, which I have now done. The artificial limitation on group
684        length has been removed - we now have only the limit on the total length of
685        the compiled pattern, which depends on the LINK_SIZE setting.
686    
687    10. Fixed a bug in the documentation for get/copy named substring when
688        duplicate names are permitted. If none of the named substrings are set, the
689        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
690        empty string.
691    
692    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
693        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
694        because the ] is interpreted as the first data character and the
695        terminating ] is not found. PCRE has been made compatible with Perl in this
696        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
697        cause memory overwriting.
698    
699    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
700        string has been matched (to stop an infinite loop). It was not recognizing
701        a conditional subpattern that could match an empty string if that
702        subpattern was within another subpattern. For example, it looped when
703        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
704        condition was not nested. This bug has been fixed.
705    
706    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
707        past the start of the subject in the presence of bytes with the top bit
708        set, for example "\x8aBCD".
709    
710    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
711        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
712    
713    14. Optimized (?!) to (*FAIL).
714    
715    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
716        This restricts code points to be within the range 0 to 0x10FFFF, excluding
717        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
718        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
719        does: it's just the validity check that is more restrictive.
720    
721    16. Inserted checks for integer overflows during escape sequence (backslash)
722        processing, and also fixed erroneous offset values for syntax errors during
723        backslash processing.
724    
725    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
726        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
727    
728    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
729        caused an overrun.
730    
731    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
732        something other than just ASCII characters) inside a group that had an
733        unlimited repeat caused a loop at compile time (while checking to see
734        whether the group could match an empty string).
735    
736    20. Debugging a pattern containing \p or \P could cause a crash. For example,
737        [\P{Any}] did so. (Error in the code for printing property names.)
738    
739    21. An orphan \E inside a character class could cause a crash.
740    
741    22. A repeated capturing bracket such as (A)? could cause a wild memory
742        reference during compilation.
743    
744    23. There are several functions in pcre_compile() that scan along a compiled
745        expression for various reasons (e.g. to see if it's fixed length for look
746        behind). There were bugs in these functions when a repeated \p or \P was
747        present in the pattern. These operators have additional parameters compared
748        with \d, etc, and these were not being taken into account when moving along
749        the compiled data. Specifically:
750    
751        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
752            length.
753    
754        (b) An item such as \pL+ within a repeated group could cause crashes or
755            loops.
756    
757        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
758            "reference to non-existent subpattern" error.
759    
760        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
761    
762    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
763        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
764    
765    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
766    
767    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
768        character were causing crashes (broken optimization).
769    
770    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
771        \p or \P) caused a compile-time loop.
772    
773    28. More problems have arisen in unanchored patterns when CRLF is a valid line
774        break. For example, the unstudied pattern [\r\n]A does not match the string
775        "\r\nA" because change 7.0/46 below moves the current point on by two
776        characters after failing to match at the start. However, the pattern \nA
777        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
778        the same is true. There doesn't seem any very clean way out of this, but
779        what I have chosen to do makes the common cases work: PCRE now takes note
780        of whether there can be an explicit match for \r or \n anywhere in the
781        pattern, and if so, 7.0/46 no longer applies. As part of this change,
782        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
783        pattern has explicit CR or LF references.
784    
785    29. Added (*CR) etc for changing newline setting at start of pattern.
786    
787    
788    Version 7.2 19-Jun-07
789    ---------------------
790    
791     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
792        which is apparently normally available under Windows.
793    
794     2. Re-jig the pcregrep tests with different newline settings in an attempt
795        to make them independent of the local environment's newline setting.
796    
797     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
798    
799     4. Some of the "internals" tests were previously cut out when the link size
800        was not 2, because the output contained actual offsets. The recent new
801        "Z" feature of pcretest means that these can be cut out, making the tests
802        usable with all link sizes.
803    
804     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
805        stack recursion. This gives a massive performance boost under BSD, but just
806        a small improvement under Linux. However, it saves one field in the frame
807        in all cases.
808    
809     6. Added more features from the forthcoming Perl 5.10:
810    
811        (a) (?-n) (where n is a string of digits) is a relative subroutine or
812            recursion call. It refers to the nth most recently opened parentheses.
813    
814        (b) (?+n) is also a relative subroutine call; it refers to the nth next
815            to be opened parentheses.
816    
817        (c) Conditions that refer to capturing parentheses can be specified
818            relatively, for example, (?(-2)... or (?(+3)...
819    
820        (d) \K resets the start of the current match so that everything before
821            is not part of it.
822    
823        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
824    
825        (f) \g{name} is another synonym - part of Perl 5.10's unification of
826            reference syntax.
827    
828        (g) (?| introduces a group in which the numbering of parentheses in each
829            alternative starts with the same number.
830    
831        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
832    
833     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
834        PCRE_INFO_JCHANGED.
835    
836     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
837        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
838        for detecting groups that can match an empty string.
839    
840     9. A pattern with a very large number of alternatives (more than several
841        hundred) was running out of internal workspace during the pre-compile
842        phase, where pcre_compile() figures out how much memory will be needed. A
843        bit of new cunning has reduced the workspace needed for groups with
844        alternatives. The 1000-alternative test pattern now uses 12 bytes of
845        workspace instead of running out of the 4096 that are available.
846    
847    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
848    
849    11. Applied patch from Google to remove an optimization that didn't quite work.
850        The report of the bug said:
851    
852          pcrecpp::RE("a*").FullMatch("aaa") matches, while
853          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
854          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
855    
856    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
857        it matched the wrong number of bytes.
858    
859    
860    Version 7.1 24-Apr-07
861    ---------------------
862    
863     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
864        that is more "standard", making use of automake and other Autotools. There
865        is some re-arrangement of the files and adjustment of comments consequent
866        on this.
867    
868     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
869        for recursive directory scanning broke on some systems because the files
870        are not scanned in any specific order and on different systems the order
871        was different. A call to "sort" has been inserted into RunGrepTest for the
872        approprate test as a short-term fix. In the longer term there may be an
873        alternative.
874    
875     3. I had an email from Eric Raymond about problems translating some of PCRE's
876        man pages to HTML (despite the fact that I distribute HTML pages, some
877        people do their own conversions for various reasons). The problems
878        concerned the use of low-level troff macros .br and .in. I have therefore
879        removed all such uses from the man pages (some were redundant, some could
880        be replaced by .nf/.fi pairs). The 132html script that I use to generate
881        HTML has been updated to handle .nf/.fi and to complain if it encounters
882        .br or .in.
883    
884     4. Updated comments in configure.ac that get placed in config.h.in and also
885        arranged for config.h to be included in the distribution, with the name
886        config.h.generic, for the benefit of those who have to compile without
887        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
888    
889     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
890        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
891        makevp.bat for the current PCRE, using the additional files
892        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
893    
894     6. A Windows user reported a minor discrepancy with test 2, which turned out
895        to be caused by a trailing space on an input line that had got lost in his
896        copy. The trailing space was an accident, so I've just removed it.
897    
898     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
899        that is needed.
900    
901     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
902        as "const" (a) because they are and (b) because it helps the PHP
903        maintainers who have recently made a script to detect big data structures
904        in the php code that should be moved to the .rodata section. I remembered
905        to update Builducptable as well, so it won't revert if ucptable.h is ever
906        re-created.
907    
908     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
909        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
910        order to be able to cut out the UTF-8 tables in the latter when UTF-8
911        support is not required. This saves 1.5-2K of code, which is important in
912        some applications.
913    
914        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
915        so as not to refer to the tables, even though these functions will never be
916        called when UTF-8 support is disabled. Otherwise there are problems with a
917        shared library.
918    
919    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
920    
921        (a) It was defining its arguments as char * instead of void *.
922    
923        (b) It was assuming that all moves were upwards in memory; this was true
924            a long time ago when I wrote it, but is no longer the case.
925    
926        The emulated memove() is provided for those environments that have neither
927        memmove() nor bcopy(). I didn't think anyone used it these days, but that
928        is clearly not the case, as these two bugs were recently reported.
929    
930    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
931        and Detrail to create the HTML documentation, the .txt form of the man
932        pages, and it removes trailing spaces from listed files. It also creates
933        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
934        case, it wraps all the #defines with #ifndefs. This script should be run
935        before "make dist".
936    
937    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
938        with Unicode property support.
939    
940        (a) For a maximizing quantifier, if the two different cases of the
941            character were of different lengths in their UTF-8 codings (there are
942            some cases like this - I found 11), and the matching function had to
943            back up over a mixture of the two cases, it incorrectly assumed they
944            were both the same length.
945    
946        (b) When PCRE was configured to use the heap rather than the stack for
947            recursion during matching, it was not correctly preserving the data for
948            the other case of a UTF-8 character when checking ahead for a match
949            while processing a minimizing repeat. If the check also involved
950            matching a wide character, but failed, corruption could cause an
951            erroneous result when trying to check for a repeat of the original
952            character.
953    
954    13. Some tidying changes to the testing mechanism:
955    
956        (a) The RunTest script now detects the internal link size and whether there
957            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
958            values substituted by "configure". (The RunGrepTest script already did
959            this for UTF-8.) The configure.ac script no longer substitutes the
960            relevant variables.
961    
962        (b) The debugging options /B and /D in pcretest show the compiled bytecode
963            with length and offset values. This means that the output is different
964            for different internal link sizes. Test 2 is skipped for link sizes
965            other than 2 because of this, bypassing the problem. Unfortunately,
966            there was also a test in test 3 (the locale tests) that used /B and
967            failed for link sizes other than 2. Rather than cut the whole test out,
968            I have added a new /Z option to pcretest that replaces the length and
969            offset values with spaces. This is now used to make test 3 independent
970            of link size. (Test 2 will be tidied up later.)
971    
972    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
973        segmentation fault instead of returning the appropriate error message.
974    
975    15. In multiline mode when the newline sequence was set to "any", the pattern
976        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
977        This doesn't seem right; it now treats the CRLF combination as the line
978        ending, and so does not match in that case. It's only a pattern such as ^$
979        that would hit this one: something like ^ABC$ would have failed after \r
980        and then tried again after \r\n.
981    
982    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
983        in an attempt to make files that differ only in their line terminators
984        compare equal. This works on Linux.
985    
986    17. Under certain error circumstances pcregrep might try to free random memory
987        as it exited. This is now fixed, thanks to valgrind.
988    
989    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
990        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
991        was because its rules for how to advance for /g after matching an empty
992        string at the end of a line did not allow for this case. They now check for
993        it specially.
994    
995    20. pcretest is supposed to handle patterns and data of any length, by
996        extending its buffers when necessary. It was getting this wrong when the
997        buffer for a data line had to be extended.
998    
999    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1000        CRLF as a newline sequence.
1001    
1002    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1003        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1004        I have nevertheless tidied it up.
1005    
1006    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1007    
1008    24. Added a man page for pcre-config.
1009    
1010    
1011    Version 7.0 19-Dec-06
1012    ---------------------
1013    
1014     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1015        moving to gcc 4.1.1.
1016    
1017     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1018        sys/time.h, which is documented as needed for this function. It doesn't
1019        seem to matter on Linux, but it showed up on some releases of OS X.
1020    
1021     3. It seems that there are systems where bytes whose values are greater than
1022        127 match isprint() in the "C" locale. The "C" locale should be the
1023        default when a C program starts up. In most systems, only ASCII printing
1024        characters match isprint(). This difference caused the output from pcretest
1025        to vary, making some of the tests fail. I have changed pcretest so that:
1026    
1027        (a) When it is outputting text in the compiled version of a pattern, bytes
1028            other than 32-126 are always shown as hex escapes.
1029    
1030        (b) When it is outputting text that is a matched part of a subject string,
1031            it does the same, unless a different locale has been set for the match
1032            (using the /L modifier). In this case, it uses isprint() to decide.
1033    
1034     4. Fixed a major bug that caused incorrect computation of the amount of memory
1035        required for a compiled pattern when options that changed within the
1036        pattern affected the logic of the preliminary scan that determines the
1037        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1038        that the computed length was too small. The symptoms of this bug were
1039        either the PCRE error "internal error: code overflow" from pcre_compile(),
1040        or a glibc crash with a message such as "pcretest: free(): invalid next
1041        size (fast)". Examples of patterns that provoked this bug (shown in
1042        pcretest format) are:
1043    
1044          /(?-x: )/x
1045          /(?x)(?-x: \s*#\s*)/
1046          /((?i)[\x{c0}])/8
1047          /(?i:[\x{c0}])/8
1048    
1049        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1050        is now done differently.
1051    
1052     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1053        wrapper classes; (b) implement a new function in the C++ scanner that is
1054        more efficient than the old way of doing things because it avoids levels of
1055        recursion in the regex matching; (c) add a paragraph to the documentation
1056        for the FullMatch() function.
1057    
1058     6. The escape sequence \n was being treated as whatever was defined as
1059        "newline". Not only was this contrary to the documentation, which states
1060        that \n is character 10 (hex 0A), but it also went horribly wrong when
1061        "newline" was defined as CRLF. This has been fixed.
1062    
1063     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1064        was being set to -1 for the "end of line" case (supposedly a value that no
1065        character can have). Though this value is never used (the check for end of
1066        line is "zero bytes in current character"), it caused compiler complaints.
1067        I've changed it to 0xffffffff.
1068    
1069     8. In pcre_version.c, the version string was being built by a sequence of
1070        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1071        string (as it is for production releases) called a macro with an empty
1072        argument. The C standard says the result of this is undefined. The gcc
1073        compiler treats it as an empty string (which was what was wanted) but it is
1074        reported that Visual C gives an error. The source has been hacked around to
1075        avoid this problem.
1076    
1077     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1078        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1079        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1080        of them did).
1081    
1082    10. Originally, pcretest opened its input and output without "b"; then I was
1083        told that "b" was needed in some environments, so it was added for release
1084        5.0 to both the input and output. (It makes no difference on Unix-like
1085        systems.) Later I was told that it is wrong for the input on Windows. I've
1086        now abstracted the modes into two macros, to make it easier to fiddle with
1087        them, and removed "b" from the input mode under Windows.
1088    
1089    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1090    
1091    12. Added -help and --help to pcretest as an official way of being reminded
1092        of the options.
1093    
1094    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1095        and pcrecpp.cc because they annoy compilers at high warning levels.
1096    
1097    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1098    
1099    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1100        scripts are not C programs :-) and which was not noticed because it works
1101        on Linux.
1102    
1103    16. pcretest is supposed to handle any length of pattern and data line (as one
1104        line or as a continued sequence of lines) by extending its input buffer if
1105        necessary. This feature was broken for very long pattern lines, leading to
1106        a string of junk being passed to pcre_compile() if the pattern was longer
1107        than about 50K.
1108    
1109    17. I have done a major re-factoring of the way pcre_compile() computes the
1110        amount of memory needed for a compiled pattern. Previously, there was code
1111        that made a preliminary scan of the pattern in order to do this. That was
1112        OK when PCRE was new, but as the facilities have expanded, it has become
1113        harder and harder to keep it in step with the real compile phase, and there
1114        have been a number of bugs (see for example, 4 above). I have now found a
1115        cunning way of running the real compile function in a "fake" mode that
1116        enables it to compute how much memory it would need, while actually only
1117        ever using a few hundred bytes of working memory and without too many
1118        tests of the mode. This should make future maintenance and development
1119        easier. A side effect of this work is that the limit of 200 on the nesting
1120        depth of parentheses has been removed (though this was never a serious
1121        limitation, I suspect). However, there is a downside: pcre_compile() now
1122        runs more slowly than before (30% or more, depending on the pattern). I
1123        hope this isn't a big issue. There is no effect on runtime performance.
1124    
1125    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1126        newline (only possible for the last line of a file) and it was a
1127        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1128    
1129    19. Added additional timing features to pcretest. (1) The -tm option now times
1130        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1131        separate command line item, by a number that specifies the number of
1132        repeats to use when timing. The default is 50000; this gives better
1133        precision, but takes uncomfortably long for very large patterns.
1134    
1135    20. Extended pcre_study() to be more clever in cases where a branch of a
1136        subpattern has no definite first character. For example, (a*|b*)[cd] would
1137        previously give no result from pcre_study(). Now it recognizes that the
1138        first character must be a, b, c, or d.
1139    
1140    21. There was an incorrect error "recursive call could loop indefinitely" if
1141        a subpattern (or the entire pattern) that was being tested for matching an
1142        empty string contained only one non-empty item after a nested subpattern.
1143        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1144        incorrectly, because the \d was being skipped in the check.
1145    
1146    22. The pcretest program now has a new pattern option /B and a command line
1147        option -b, which is equivalent to adding /B to every pattern. This causes
1148        it to show the compiled bytecode, without the additional information that
1149        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1150        is the same as /B/I).
1151    
1152    23. A new optimization is now able automatically to treat some sequences such
1153        as a*b as a*+b. More specifically, if something simple (such as a character
1154        or a simple class like \d) has an unlimited quantifier, and is followed by
1155        something that cannot possibly match the quantified thing, the quantifier
1156        is automatically "possessified".
1157    
1158    24. A recursive reference to a subpattern whose number was greater than 39
1159        went wrong under certain circumstances in UTF-8 mode. This bug could also
1160        have affected the operation of pcre_study().
1161    
1162    25. Realized that a little bit of performance could be had by replacing
1163        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1164    
1165    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1166    
1167    27. Possessive quantifiers such as a++ were previously implemented by turning
1168        them into atomic groups such as ($>a+). Now they have their own opcodes,
1169        which improves performance. This includes the automatically created ones
1170        from 23 above.
1171    
1172    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1173        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1174        the first matched character to be a colon. This applied both to named and
1175        numbered groups.
1176    
1177    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1178    
1179    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1180        building PCRE on Windows easier, so I have included it in the distribution.
1181    
1182    31. There is now a check in pcretest against a ridiculously large number being
1183        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1184        loop, the loop is abandoned.
1185    
1186    32. Forward references to subpatterns in conditions such as (?(2)...) where
1187        subpattern 2 is defined later cause pcre_compile() to search forwards in
1188        the pattern for the relevant set of parentheses. This search went wrong
1189        when there were unescaped parentheses in a character class, parentheses
1190        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1191    
1192    33. "Subroutine" calls and backreferences were previously restricted to
1193        referencing subpatterns earlier in the regex. This restriction has now
1194        been removed.
1195    
1196    34. Added a number of extra features that are going to be in Perl 5.10. On the
1197        whole, these are just syntactic alternatives for features that PCRE had
1198        previously implemented using the Python syntax or my own invention. The
1199        other formats are all retained for compatibility.
1200    
1201        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1202            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1203            also .NET compatible.
1204    
1205        (b) A recursion or subroutine call to a named group can now be defined as
1206            (?&name) as well as (?P>name).
1207    
1208        (c) A backreference to a named group can now be defined as \k<name> or
1209            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1210            5.10, are also .NET compatible.
1211    
1212        (d) A conditional reference to a named group can now use the syntax
1213            (?(<name>) or (?('name') as well as (?(name).
1214    
1215        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1216            groups (named and numbered) that are never evaluated inline, but can be
1217            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1218            is always false. There may be only one alternative in such a group.
1219    
1220        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1221            as the simple (?(R). The condition is true only if the most recent
1222            recursion is that of the given number or name. It does not search out
1223            through the entire recursion stack.
1224    
1225        (g) The escape \gN or \g{N} has been added, where N is a positive or
1226            negative number, specifying an absolute or relative reference.
1227    
1228    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1229        some "unreachable code" warnings.
1230    
1231    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1232        things, this adds five new scripts.
1233    
1234    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1235        There were also incompatibilities regarding the handling of \Q..\E inside
1236        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1237        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1238    
1239    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1240        matches an empty string, and forcibly breaks the loop. There were bugs in
1241        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1242        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1243        separate and independent bugs (that affected different cases) have been
1244        fixed.
1245    
1246    39. Refactored the code to abolish the use of different opcodes for small
1247        capturing bracket numbers. This is a tidy that I avoided doing when I
1248        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1249        The new approach is not only tidier, it makes it possible to reduce the
1250        memory needed to fix the previous bug (38).
1251    
1252    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1253        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1254        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1255        mode.
1256    
1257    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1258        report.
1259    
1260    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1261        copy construction and assignment in the C++ wrapper.
1262    
1263    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1264        couple of bugs that could have given wrong results in the "--newline=crlf"
1265        case.
1266    
1267    44. Added a number of casts and did some reorganization of signed/unsigned int
1268        variables following suggestions from Dair Grant. Also renamed the variable
1269        "this" as "item" because it is a C++ keyword.
1270    
1271    45. Arranged for dftables to add
1272    
1273          #include "pcre_internal.h"
1274    
1275        to pcre_chartables.c because without it, gcc 4.x may remove the array
1276        definition from the final binary if PCRE is built into a static library and
1277        dead code stripping is activated.
1278    
1279    46. For an unanchored pattern, if a match attempt fails at the start of a
1280        newline sequence, and the newline setting is CRLF or ANY, and the next two
1281        characters are CRLF, advance by two characters instead of one.
1282    
1283    
1284    Version 6.7 04-Jul-06
1285    ---------------------
1286    
1287     1. In order to handle tests when input lines are enormously long, pcretest has
1288        been re-factored so that it automatically extends its buffers when
1289        necessary. The code is crude, but this _is_ just a test program. The
1290        default size has been increased from 32K to 50K.
1291    
1292     2. The code in pcre_study() was using the value of the re argument before
1293        testing it for NULL. (Of course, in any sensible call of the function, it
1294        won't be NULL.)
1295    
1296     3. The memmove() emulation function in pcre_internal.h, which is used on
1297        systems that lack both memmove() and bcopy() - that is, hardly ever -
1298        was missing a "static" storage class specifier.
1299    
1300     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1301        containing an extended class (one that cannot be represented by a bitmap
1302        because it contains high-valued characters or Unicode property items, e.g.
1303        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1304        pattern, but PCRE should not loop if you do not (it no longer does).
1305        [Detail: two cases were found: (a) a repeated subpattern containing an
1306        extended class; (b) a recursive reference to a subpattern that followed a
1307        previous extended class. It wasn't skipping over the extended class
1308        correctly when UTF-8 mode was not set.]
1309    
1310     5. A negated single-character class was not being recognized as fixed-length
1311        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1312        compile error "lookbehind assertion is not fixed length".
1313    
1314     6. The RunPerlTest auxiliary script was showing an unexpected difference
1315        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1316        write a Perl script that can interpret lines of an input file either as
1317        byte characters or as UTF-8, which is what "perltest" was being required to
1318        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1319        can't do is switch easily at run time between having the "use utf8;" pragma
1320        or not. In the end, I fudged it by using the RunPerlTest script to insert
1321        "use utf8;" explicitly for the UTF-8 tests.
1322    
1323     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1324        the end of the subject string, contrary to the documentation and to what
1325        Perl does. This was true of both matching functions. Now it matches only at
1326        the start of the subject and immediately after *internal* newlines.
1327    
1328     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1329        a pointer to an int instead of a pointer to an unsigned long int. This
1330        caused problems on 64-bit systems.
1331    
1332     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1333        instance of the 'standard' template library not being so standard".
1334    
1335    10. There was no check on the number of named subpatterns nor the maximum
1336        length of a subpattern name. The product of these values is used to compute
1337        the size of the memory block for a compiled pattern. By supplying a very
1338        long subpattern name and a large number of named subpatterns, the size
1339        computation could be caused to overflow. This is now prevented by limiting
1340        the length of names to 32 characters, and the number of named subpatterns
1341        to 10,000.
1342    
1343    11. Subpatterns that are repeated with specific counts have to be replicated in
1344        the compiled pattern. The size of memory for this was computed from the
1345        length of the subpattern and the repeat count. The latter is limited to
1346        65535, but there was no limit on the former, meaning that integer overflow
1347        could in principle occur. The compiled length of a repeated subpattern is
1348        now limited to 30,000 bytes in order to prevent this.
1349    
1350    12. Added the optional facility to have named substrings with the same name.
1351    
1352    13. Added the ability to use a named substring as a condition, using the
1353        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1354        are numbers (not recommended). Forward references are permitted.
1355    
1356    14. Added forward references in named backreferences (if you see what I mean).
1357    
1358    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1359        pattern could run off the end of the subject. For example, the pattern
1360        "(?s)(.{1,5})"8 did this with the subject "ab".
1361    
1362    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1363        PCRE_CASELESS was set when matching characters that were quantified with ?
1364        or *.
1365    
1366    17. A character class other than a single negated character that had a minimum
1367        but no maximum quantifier - for example [ab]{6,} - was not handled
1368        correctly by pce_dfa_exec(). It would match only one character.
1369    
1370    18. A valid (though odd) pattern that looked like a POSIX character
1371        class but used an invalid character after [ (for example [[,abc,]]) caused
1372        pcre_compile() to give the error "Failed: internal error: code overflow" or
1373        in some cases to crash with a glibc free() error. This could even happen if
1374        the pattern terminated after [[ but there just happened to be a sequence of
1375        letters, a binary zero, and a closing ] in the memory that followed.
1376    
1377    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1378        over the years. Originally (before any Unicode support), just the bottom 8
1379        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1380        output from "man perlunicode" includes this:
1381    
1382          The regular expression compiler produces polymorphic opcodes.  That
1383          is, the pattern adapts to the data and automatically switches to
1384          the Unicode character scheme when presented with Unicode data--or
1385          instead uses a traditional byte scheme when presented with byte
1386          data.
1387    
1388        Sadly, a wide octal escape does not cause a switch, and in a string with
1389        no other multibyte characters, these octal escapes are treated as before.
1390        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1391        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1392        Unicode string.
1393    
1394        I have not perpetrated such confusion in PCRE. Up till now, it took just
1395        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1396        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1397        translate to the appropriate multibyte character.
1398    
1399    29. Applied some refactoring to reduce the number of warnings from Microsoft
1400        and Borland compilers. This has included removing the fudge introduced
1401        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1402        a warning about an unused variable.
1403    
1404    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1405        characters since release 4.0, because Perl (from release 5.004) does not.
1406        [Or at least, is documented not to: some releases seem to be in conflict
1407        with the documentation.] However, when a pattern was studied with
1408        pcre_study() and all its branches started with \s, PCRE still included VT
1409        as a possible starting character. Of course, this did no harm; it just
1410        caused an unnecessary match attempt.
1411    
1412    22. Removed a now-redundant internal flag bit that recorded the fact that case
1413        dependency changed within the pattern. This was once needed for "required
1414        byte" processing, but is no longer used. This recovers a now-scarce options
1415        bit. Also moved the least significant internal flag bit to the most-
1416        significant bit of the word, which was not previously used (hangover from
1417        the days when it was an int rather than a uint) to free up another bit for
1418        the future.
1419    
1420    23. Added support for CRLF line endings as well as CR and LF. As well as the
1421        default being selectable at build time, it can now be changed at runtime
1422        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1423        specify that it is scanning data with non-default line endings.
1424    
1425    24. Changed the definition of CXXLINK to make it agree with the definition of
1426        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1427    
1428    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1429        recursions. This makes a big different to stack usage for some patterns.
1430    
1431    26. If a subpattern containing a named recursion or subroutine reference such
1432        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1433        the space required for the compiled pattern went wrong and gave too small a
1434        value. Depending on the environment, this could lead to "Failed: internal
1435        error: code overflow at offset 49" or "glibc detected double free or
1436        corruption" errors.
1437    
1438    27. Applied patches from Google (a) to support the new newline modes and (b) to
1439        advance over multibyte UTF-8 characters in GlobalReplace.
1440    
1441    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1442        difference for some implementation of PCRE in some Windows version.
1443    
1444    29. Added some extra testing facilities to pcretest:
1445    
1446        \q<number>   in a data line sets the "match limit" value
1447        \Q<number>   in a data line sets the "match recursion limt" value
1448        -S <number>  sets the stack size, where <number> is in megabytes
1449    
1450        The -S option isn't available for Windows.
1451    
1452    
1453    Version 6.6 06-Feb-06
1454    ---------------------
1455    
1456     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1457        in pcreposix.h. I have copied the definition from pcre.h.
1458    
1459     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1460        because pcre.h is no longer a built file.
1461    
1462     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1463        not normally included in the compiled code.
1464    
1465    
1466    Version 6.5 01-Feb-06
1467    ---------------------
1468    
1469     1. When using the partial match feature with pcre_dfa_exec(), it was not
1470        anchoring the second and subsequent partial matches at the new starting
1471        point. This could lead to incorrect results. For example, with the pattern
1472        /1234/, partially matching against "123" and then "a4" gave a match.
1473    
1474     2. Changes to pcregrep:
1475    
1476        (a) All non-match returns from pcre_exec() were being treated as failures
1477            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1478            error message is output. Some extra information is given for the
1479            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1480            probably the only errors that are likely to be caused by users (by
1481            specifying a regex that has nested indefinite repeats, for instance).
1482            If there are more than 20 of these errors, pcregrep is abandoned.
1483    
1484        (b) A binary zero was treated as data while matching, but terminated the
1485            output line if it was written out. This has been fixed: binary zeroes
1486            are now no different to any other data bytes.
1487    
1488        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1489            used to set a locale for matching. The --locale=xxxx long option has
1490            been added (no short equivalent) to specify a locale explicitly on the
1491            pcregrep command, overriding the environment variables.
1492    
1493        (d) When -B was used with -n, some line numbers in the output were one less
1494            than they should have been.
1495    
1496        (e) Added the -o (--only-matching) option.
1497    
1498        (f) If -A or -C was used with -c (count only), some lines of context were
1499            accidentally printed for the final match.
1500    
1501        (g) Added the -H (--with-filename) option.
1502    
1503        (h) The combination of options -rh failed to suppress file names for files
1504            that were found from directory arguments.
1505    
1506        (i) Added the -D (--devices) and -d (--directories) options.
1507    
1508        (j) Added the -F (--fixed-strings) option.
1509    
1510        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1511    
1512        (l) Added the --colo(u)r option.
1513    
1514        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1515            is not present by default.
1516    
1517     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1518        items such as (?R) or (?1), when the recursion could match a number of
1519        alternatives. If it matched one of the alternatives, but subsequently,
1520        outside the recursion, there was a failure, the code tried to back up into
1521        the recursion. However, because of the way PCRE is implemented, this is not
1522        possible, and the result was an incorrect result from the match.
1523    
1524        In order to prevent this happening, the specification of recursion has
1525        been changed so that all such subpatterns are automatically treated as
1526        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1527    
1528     4. I had overlooked the fact that, in some locales, there are characters for
1529        which isalpha() is true but neither isupper() nor islower() are true. In
1530        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1531        and ordfeminine) are like this. This affected the treatment of \w and \W
1532        when they appeared in character classes, but not when they appeared outside
1533        a character class. The bit map for "word" characters is now created
1534        separately from the results of isalnum() instead of just taking it from the
1535        upper, lower, and digit maps. (Plus the underscore character, of course.)
1536    
1537     5. The above bug also affected the handling of POSIX character classes such as
1538        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1539        permanent tables. Instead, the bit maps for such a class were previously
1540        created as the appropriate unions of the upper, lower, and digit bitmaps.
1541        Now they are created by subtraction from the [[:word:]] class, which has
1542        its own bitmap.
1543    
1544     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1545        It is created by subtracting the vertical space characters (\x09, \x0a,
1546        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1547        subtraction was done in the overall bitmap for a character class, meaning
1548        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1549        be recognized. This bug has been fixed.
1550    
1551     7. Patches from the folks at Google:
1552    
1553          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1554          real life, but is still worth protecting against".
1555    
1556          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1557          regular expressions".
1558    
1559          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1560          have it.
1561    
1562          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1563          "configure" and the latter not, in order to fix a problem somebody had
1564          with compiling the Arg class on HP-UX.
1565    
1566          (e) Improve the error-handling of the C++ wrapper a little bit.
1567    
1568          (f) New tests for checking recursion limiting.
1569    
1570     8. The pcre_memmove() function, which is used only if the environment does not
1571        have a standard memmove() function (and is therefore rarely compiled),
1572        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1573        returning a result (though PCRE never actually uses the result).
1574    
1575     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1576        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1577        returned instead of calling malloc() with an overflowing number that would
1578        most likely cause subsequent chaos.
1579    
1580    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1581    
1582    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1583        with this option is matched, the nmatch and pmatch options of regexec() are
1584        ignored.
1585    
1586    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1587        provided in case anyone wants to the the POSIX interface with UTF-8
1588        strings.
1589    
1590    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1591        C++ linking (needed for some HP-UX environments).
1592    
1593    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1594        (unused parameter) and in the pcre_printint() function (omitted "default"
1595        switch label when the default is to do nothing).
1596    
1597    15. Added some code to make it possible, when PCRE is compiled as a C++
1598        library, to replace subject pointers for pcre_exec() with a smart pointer
1599        class, thus making it possible to process discontinuous strings.
1600    
1601    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1602        much the same function. They were added by different people who were trying
1603        to make PCRE easy to compile on non-Unix systems. It has been suggested
1604        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1605        for compiling on Windows systems. I have therefore replaced it with
1606        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1607        defaults to "extern" for C or "extern C" for C++, which works fine on
1608        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1609        SCOPE with something explicit in config.h. In addition:
1610    
1611        (a) pcreposix.h still had just "extern" instead of either of these macros;
1612            I have replaced it with PCRE_DATA_SCOPE.
1613    
1614        (b) Functions such as _pcre_xclass(), which are internal to the library,
1615            but external in the C sense, all had PCRE_EXPORT in their definitions.
1616            This is apparently wrong for the Windows case, so I have removed it.
1617            (It makes no difference on Unix-like systems.)
1618    
1619    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1620        of recursive calls to match(). This is different to MATCH_LIMIT because
1621        that limits the total number of calls to match(), not all of which increase
1622        the depth of recursion. Limiting the recursion depth limits the amount of
1623        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1624        when PCRE is compiled, and changed at run time. A patch from Google adds
1625        this functionality to the C++ interface.
1626    
1627    18. Changes to the handling of Unicode character properties:
1628    
1629        (a) Updated the table to Unicode 4.1.0.
1630    
1631        (b) Recognize characters that are not in the table as "Cn" (undefined).
1632    
1633        (c) I revised the way the table is implemented to a much improved format
1634            which includes recognition of ranges. It now supports the ranges that
1635            are defined in UnicodeData.txt, and it also amalgamates other
1636            characters into ranges. This has reduced the number of entries in the
1637            table from around 16,000 to around 3,000, thus reducing its size
1638            considerably. I realized I did not need to use a tree structure after
1639            all - a binary chop search is just as efficient. Having reduced the
1640            number of entries, I extended their size from 6 bytes to 8 bytes to
1641            allow for more data.
1642    
1643        (d) Added support for Unicode script names via properties such as \p{Han}.
1644    
1645    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1646        matching that character.
1647    
1648    20. When matching a repeated Unicode property with a minimum greater than zero,
1649        (for example \pL{2,}), PCRE could look past the end of the subject if it
1650        reached it while seeking the minimum number of characters. This could
1651        happen only if some of the characters were more than one byte long, because
1652        there is a check for at least the minimum number of bytes.
1653    
1654    21. Refactored the implementation of \p and \P so as to be more general, to
1655        allow for more different types of property in future. This has changed the
1656        compiled form incompatibly. Anybody with saved compiled patterns that use
1657        \p or \P will have to recompile them.
1658    
1659    22. Added "Any" and "L&" to the supported property types.
1660    
1661    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1662        but give a compile time error if the value is greater than 0xff.
1663    
1664    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1665        accidentally not being installed or uninstalled.
1666    
1667    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1668        made were to insert the current release number. This seemed silly, because
1669        it made things harder for people building PCRE on systems that don't run
1670        "configure". I have turned pcre.h into a distributed file, no longer built
1671        by "configure", with the version identification directly included. There is
1672        no longer a pcre.h.in file.
1673    
1674        However, this change necessitated a change to the pcre-config script as
1675        well. It is built from pcre-config.in, and one of the substitutions was the
1676        release number. I have updated configure.ac so that ./configure now finds
1677        the release number by grepping pcre.h.
1678    
1679    26. Added the ability to run the tests under valgrind.
1680    
1681    
1682    Version 6.4 05-Sep-05
1683    ---------------------
1684    
1685     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1686        "--" to be printed when multiple files were scanned, even when none of the
1687        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1688        consider it to be a bug, and have restored the previous behaviour.
1689    
1690     2. A couple of code tidies to get rid of compiler warnings.
1691    
1692     3. The pcretest program used to cheat by referring to symbols in the library
1693        whose names begin with _pcre_. These are internal symbols that are not
1694        really supposed to be visible externally, and in some environments it is
1695        possible to suppress them. The cheating is now confined to including
1696        certain files from the library's source, which is a bit cleaner.
1697    
1698     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1699        file's purpose clearer.
1700    
1701     5. Reorganized pcre_ucp_findchar().
1702    
1703    
1704    Version 6.3 15-Aug-05
1705    ---------------------
1706    
1707     1. The file libpcre.pc.in did not have general read permission in the tarball.
1708    
1709     2. There were some problems when building without C++ support:
1710    
1711        (a) If C++ support was not built, "make install" and "make test" still
1712            tried to test it.
1713    
1714        (b) There were problems when the value of CXX was explicitly set. Some
1715            changes have been made to try to fix these, and ...
1716    
1717        (c) --disable-cpp can now be used to explicitly disable C++ support.
1718    
1719        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1720            backslash in a target when C++ was disabled. This confuses some
1721            versions of "make", apparently. Using an intermediate variable solves
1722            this. (Same for CPP_LOBJ.)
1723    
1724     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1725        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1726        necessary on certain architectures.
1727    
1728     4. Added a setting of -export-symbols-regex to the link command to remove
1729        those symbols that are exported in the C sense, but actually are local
1730        within the library, and not documented. Their names all begin with
1731        "_pcre_". This is not a perfect job, because (a) we have to except some
1732        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1733        available (and never for static libraries). I have made a note to try to
1734        find a way round (a) in the future.
1735    
1736    
1737    Version 6.2 01-Aug-05
1738    ---------------------
1739    
1740     1. There was no test for integer overflow of quantifier values. A construction
1741        such as {1111111111111111} would give undefined results. What is worse, if
1742        a minimum quantifier for a parenthesized subpattern overflowed and became
1743        negative, the calculation of the memory size went wrong. This could have
1744        led to memory overwriting.
1745    
1746     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1747    
1748     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1749        operating environments where this matters.
1750    
1751     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1752        PCRE options from within the C++ wrapper.
1753    
1754     5. Named capturing subpatterns were not being correctly counted when a pattern
1755        was compiled. This caused two problems: (a) If there were more than 100
1756        such subpatterns, the calculation of the memory needed for the whole
1757        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1758        back references of the form \12, where the number was greater than 9, were
1759        not recognized as back references, even though there were sufficient
1760        previous subpatterns.
1761    
1762     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1763        versions of gcc, e.g. 2.95.4.
1764    
1765    
1766  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1767  ---------------------  ---------------------
1768    

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