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8        was out-of-date, and there was no check on the pcre_compile() error code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

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