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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.01 11-Dec-09
5    ----------------------
6    
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
11    
12    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13        the pattern is reset in the first branch, pcre_compile() failed with
14        "internal error: code overflow at offset...". This happened only when
15        the reset was to the original external option setting. (An optimization
16        abstracts leading options settings into an external setting, which was the
17        cause of this.)
18    
19    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21        assertion pattern did not match (meaning that the assertion was true), it
22        was incorrectly treated as false if the SKIP had been reached during the
23        matching. This also applied to assertions used as conditions.
24    
25    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
26        assertion subpattern, including such a pattern used as a condition,
27        unpredictable results occurred, instead of the error return
28        PCRE_ERROR_DFA_UITEM.
29    
30    5.  The C++ GlobalReplace function was not working like Perl for the special
31        situation when an empty string is matched. It now does the fancy magic
32        stuff that is necessary.
33    
34    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
35        removed. (These were left over from very, very early versions of PCRE.)
36    
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
39    
40        (a) Change DEBUG to PCRE_DEBUG.
41    
42        (b) In pcre_compile(), rename the member of the "branch_chain" structure
43            called "current" as "current_branch", to prevent a collision with the
44            Linux macro when compiled as a kernel module.
45    
46        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
47            prevent a collision with the Linux macro when compiled as a kernel
48            module.
49    
50    8.  In pcre_compile() there are some checks for integer overflows that used to
51        cast potentially large values to (double). This has been changed to that
52        when building, a check for int64_t is made, and if it is found, it is used
53        instead, thus avoiding the use of floating point arithmetic. (There is no
54        other use of FP in PCRE.) If int64_t is not found, the fallback is to
55        double.
56    
57    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
58        2005 (difference between two addresses compared to an unsigned value).
59    
60    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
61        custom one, because of the following reported problem in Windows:
62    
63          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
64            under Win32.
65          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
66            therefore missing the function definition.
67          - The compiler thus generates a "C" signature for the test function.
68          - The linker fails to find the "C" function.
69          - PCRE fails to configure if asked to do so against libbz2.
70    
71    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
72        messages were output:
73    
74          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
75          rerunning libtoolize, to keep the correct libtool macros in-tree.
76          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
77    
78        I have done both of these things.
79    
80    
81    
82    Version 8.00 19-Oct-09
83    ----------------------
84    
85    1.  The table for translating pcre_compile() error codes into POSIX error codes
86        was out-of-date, and there was no check on the pcre_compile() error code
87        being within the table. This could lead to an OK return being given in
88        error.
89    
90    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
91        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
92        in a Windows environment.
93    
94    3.  The pcregrep --count option prints the count for each file even when it is
95        zero, as does GNU grep. However, pcregrep was also printing all files when
96        --files-with-matches was added. Now, when both options are given, it prints
97        counts only for those files that have at least one match. (GNU grep just
98        prints the file name in this circumstance, but including the count seems
99        more useful - otherwise, why use --count?) Also ensured that the
100        combination -clh just lists non-zero counts, with no names.
101    
102    4.  The long form of the pcregrep -F option was incorrectly implemented as
103        --fixed_strings instead of --fixed-strings. This is an incompatible change,
104        but it seems right to fix it, and I didn't think it was worth preserving
105        the old behaviour.
106    
107    5.  The command line items --regex=pattern and --regexp=pattern were not
108        recognized by pcregrep, which required --regex pattern or --regexp pattern
109        (with a space rather than an '='). The man page documented the '=' forms,
110        which are compatible with GNU grep; these now work.
111    
112    6.  No libpcreposix.pc file was created for pkg-config; there was just
113        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
114    
115    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
116        when UCP support is not needed, by modifying the Python script that
117        generates it from Unicode data files. This should not matter if the module
118        is correctly used as a library, but I received one complaint about 50K of
119        unwanted data. My guess is that the person linked everything into his
120        program rather than using a library. Anyway, it does no harm.
121    
122    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
123        was a minimum greater than 1 for a wide character in a possessive
124        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
125        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
126        character. Chaos in the form of incorrect output or a compiling loop could
127        result.
128    
129    9.  The restrictions on what a pattern can contain when partial matching is
130        requested for pcre_exec() have been removed. All patterns can now be
131        partially matched by this function. In addition, if there are at least two
132        slots in the offset vector, the offset of the earliest inspected character
133        for the match and the offset of the end of the subject are set in them when
134        PCRE_ERROR_PARTIAL is returned.
135    
136    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
137        synonymous with PCRE_PARTIAL, for backwards compatibility, and
138        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
139        and may be more useful for multi-segment matching.
140    
141    11. Partial matching with pcre_exec() is now more intuitive. A partial match
142        used to be given if ever the end of the subject was reached; now it is
143        given only if matching could not proceed because another character was
144        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
145        string "Z", which now yields "no match" instead of "partial match". In the
146        case of pcre_dfa_exec(), "no match" is given if every matching path for the
147        final character ended with (*FAIL).
148    
149    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
150        if the pattern had a "must contain" character that was already found in the
151        earlier partial match, unless partial matching was again requested. For
152        example, with the pattern /dog.(body)?/, the "must contain" character is
153        "g". If the first part-match was for the string "dog", restarting with
154        "sbody" failed. This bug has been fixed.
155    
156    13. The string returned by pcre_dfa_exec() after a partial match has been
157        changed so that it starts at the first inspected character rather than the
158        first character of the match. This makes a difference only if the pattern
159        starts with a lookbehind assertion or \b or \B (\K is not supported by
160        pcre_dfa_exec()). It's an incompatible change, but it makes the two
161        matching functions compatible, and I think it's the right thing to do.
162    
163    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
164        so that the demonstration program is easily available in environments where
165        PCRE has not been installed from source.
166    
167    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
168        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
169        library.
170    
171    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
172        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
173        is not the first non-POSIX option to be added. Clearly some people find
174        these options useful.
175    
176    17. If a caller to the POSIX matching function regexec() passes a non-zero
177        value for nmatch with a NULL value for pmatch, the value of
178        nmatch is forced to zero.
179    
180    18. RunGrepTest did not have a test for the availability of the -u option of
181        the diff command, as RunTest does. It now checks in the same way as
182        RunTest, and also checks for the -b option.
183    
184    19. If an odd number of negated classes containing just a single character
185        interposed, within parentheses, between a forward reference to a named
186        subpattern and the definition of the subpattern, compilation crashed with
187        an internal error, complaining that it could not find the referenced
188        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
189        [The bug was that it was starting one character too far in when skipping
190        over the character class, thus treating the ] as data rather than
191        terminating the class. This meant it could skip too much.]
192    
193    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
194        /g option in pcretest when the pattern contains \K, which makes it possible
195        to have an empty string match not at the start, even when the pattern is
196        anchored. Updated pcretest and pcredemo to use this option.
197    
198    21. If the maximum number of capturing subpatterns in a recursion was greater
199        than the maximum at the outer level, the higher number was returned, but
200        with unset values at the outer level. The correct (outer level) value is
201        now given.
202    
203    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
204        PCRE did not set those parentheses (unlike Perl). I have now found a way to
205        make it do so. The string so far is captured, making this feature
206        compatible with Perl.
207    
208    23. The tests have been re-organized, adding tests 11 and 12, to make it
209        possible to check the Perl 5.10 features against Perl 5.10.
210    
211    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
212        pattern matches a fixed length string. PCRE did not allow this; now it
213        does. Neither allows recursion.
214    
215    25. I finally figured out how to implement a request to provide the minimum
216        length of subject string that was needed in order to match a given pattern.
217        (It was back references and recursion that I had previously got hung up
218        on.) This code has now been added to pcre_study(); it finds a lower bound
219        to the length of subject needed. It is not necessarily the greatest lower
220        bound, but using it to avoid searching strings that are too short does give
221        some useful speed-ups. The value is available to calling programs via
222        pcre_fullinfo().
223    
224    26. While implementing 25, I discovered to my embarrassment that pcretest had
225        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
226        study optimizations had never been tested with that matching function.
227        Oops. What is worse, even when it was passed study data, there was a bug in
228        pcre_dfa_exec() that meant it never actually used it. Double oops. There
229        were also very few tests of studied patterns with pcre_dfa_exec().
230    
231    27. If (?| is used to create subpatterns with duplicate numbers, they are now
232        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
233        on the other side of the coin, they are no longer allowed to have different
234        names, because these cannot be distinguished in PCRE, and this has caused
235        confusion. (This is a difference from Perl.)
236    
237    28. When duplicate subpattern names are present (necessarily with different
238        numbers, as required by 27 above), and a test is made by name in a
239        conditional pattern, either for a subpattern having been matched, or for
240        recursion in such a pattern, all the associated numbered subpatterns are
241        tested, and the overall condition is true if the condition is true for any
242        one of them. This is the way Perl works, and is also more like the way
243        testing by number works.
244    
245    
246    Version 7.9 11-Apr-09
247    ---------------------
248    
249    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
250        (pcretest), all targets were linked against these libraries. This included
251        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
252        libraries. This caused unwanted dependencies to be created. This problem
253        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
254        pcretest is linked with readline.
255    
256    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
257        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
258        moved outside it again, because FALSE and TRUE are already defined in AIX,
259        but BOOL is not.
260    
261    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
262        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
263    
264    4.  The pcregrep documentation said spaces were inserted as well as colons (or
265        hyphens) following file names and line numbers when outputting matching
266        lines. This is not true; no spaces are inserted. I have also clarified the
267        wording for the --colour (or --color) option.
268    
269    5.  In pcregrep, when --colour was used with -o, the list of matching strings
270        was not coloured; this is different to GNU grep, so I have changed it to be
271        the same.
272    
273    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
274        each matching line was coloured. Now it goes on to look for further matches
275        of any of the test patterns, which is the same behaviour as GNU grep.
276    
277    7.  A pattern that could match an empty string could cause pcregrep to loop; it
278        doesn't make sense to accept an empty string match in pcregrep, so I have
279        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
280        seems to be how GNU grep behaves.
281    
282    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
283        start or after a newline", because the conditional assertion was not being
284        correctly handled. The rule now is that both the assertion and what follows
285        in the first alternative must satisfy the test.
286    
287    9.  If auto-callout was enabled in a pattern with a conditional group whose
288        condition was an assertion, PCRE could crash during matching, both with
289        pcre_exec() and pcre_dfa_exec().
290    
291    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
292        used for matching.
293    
294    11. Unicode property support in character classes was not working for
295        characters (bytes) greater than 127 when not in UTF-8 mode.
296    
297    12. Added the -M command line option to pcretest.
298    
299    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
300    
301    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
302    
303    16. Added comments and documentation about mis-use of no_arg in the C++
304        wrapper.
305    
306    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
307        from Martin Jerabek that uses macro names for all relevant character and
308        string constants.
309    
310    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
311        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
312        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
313        these, but not everybody uses configure.
314    
315    19. A conditional group that had only one branch was not being correctly
316        recognized as an item that could match an empty string. This meant that an
317        enclosing group might also not be so recognized, causing infinite looping
318        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
319        with the subject "ab", where knowledge that the repeated group can match
320        nothing is needed in order to break the loop.
321    
322    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
323        exec(), but without supplying a callout function, matching went wrong.
324    
325    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
326        leak if the size of the offset vector was greater than 30. When the vector
327        is smaller, the saved offsets during recursion go onto a local stack
328        vector, but for larger vectors malloc() is used. It was failing to free
329        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
330        error, in fact).
331    
332    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
333        heapframe that is used only when UTF-8 support is enabled. This caused no
334        problem, but was untidy.
335    
336    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
337        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
338        included within another project.
339    
340    24. Steven Van Ingelgem's patches to add more options to the CMake support,
341        slightly modified by me:
342    
343          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
344              not building pcregrep.
345    
346          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
347              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
348    
349    25. Forward references, both numeric and by name, in patterns that made use of
350        duplicate group numbers, could behave incorrectly or give incorrect errors,
351        because when scanning forward to find the reference group, PCRE was not
352        taking into account the duplicate group numbers. A pattern such as
353        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
354    
355    26. Changed a few more instances of "const unsigned char *" to USPTR, making
356        the feature of a custom pointer more persuasive (as requested by a user).
357    
358    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
359        pcretest.c, inside #ifndefs, because it seems they are sometimes already
360        pre-defined.
361    
362    28. Added support for (*UTF8) at the start of a pattern.
363    
364    29. Arrange for flags added by the "release type" setting in CMake to be shown
365        in the configuration summary.
366    
367    
368    Version 7.8 05-Sep-08
369    ---------------------
370    
371    1.  Replaced UCP searching code with optimized version as implemented for Ad
372        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
373        stage table and inline lookup instead of a function, giving speed ups of 2
374        to 5 times on some simple patterns that I tested. Permission was given to
375        distribute the MultiStage2.py script that generates the tables (it's not in
376        the tarball, but is in the Subversion repository).
377    
378    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
379        scripts.
380    
381    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
382        a group with a zero qualifier. The result of the study could be incorrect,
383        or the function might crash, depending on the pattern.
384    
385    4.  Caseless matching was not working for non-ASCII characters in back
386        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
387        It now works when Unicode Property Support is available.
388    
389    5.  In pcretest, an escape such as \x{de} in the data was always generating
390        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
391        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
392        truncation.
393    
394    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
395    
396    7.  Added two (int) casts to pcregrep when printing the difference of two
397        pointers, in case they are 64-bit values.
398    
399    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
400        test 2 if it fails.
401    
402    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
403        and a #define of that name to empty if it is not externally set. This is to
404        allow users of MSVC to set it if necessary.
405    
406    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
407        the convenience functions in the pcre_get.c source file.
408    
409    11. An option change at the start of a pattern that had top-level alternatives
410        could cause overwriting and/or a crash. This command provoked a crash in
411        some environments:
412    
413          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
414    
415        This potential security problem was recorded as CVE-2008-2371.
416    
417    12. For a pattern where the match had to start at the beginning or immediately
418        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
419        pcre_dfa_exec() could read past the end of the passed subject if there was
420        no match. To help with detecting such bugs (e.g. with valgrind), I modified
421        pcretest so that it places the subject at the end of its malloc-ed buffer.
422    
423    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
424        exec() might read past the end of the data buffer in UTF-8 mode.
425    
426    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
427        the data contained the byte 0x85 as part of a UTF-8 character within its
428        first line. This applied both to normal and DFA matching.
429    
430    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
431        /^[^d]*?$/8 failed to match "abc".
432    
433    16. Added a missing copyright notice to pcrecpp_internal.h.
434    
435    17. Make it more clear in the documentation that values returned from
436        pcre_exec() in ovector are byte offsets, not character counts.
437    
438    18. Tidied a few places to stop certain compilers from issuing warnings.
439    
440    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
441        supplied by Stefan Weber. I made a further small update for 7.8 because
442        there is a change of source arrangements: the pcre_searchfuncs.c module is
443        replaced by pcre_ucd.c.
444    
445    
446    Version 7.7 07-May-08
447    ---------------------
448    
449    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
450        a string to a long long, pretend we don't even have a long long." This is
451        done by checking for the strtoq, strtoll, and _strtoi64 functions.
452    
453    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
454        pre-7.6 versions, which defined a global no_arg variable instead of putting
455        it in the RE class. (See also #8 below.)
456    
457    3.  Remove a line of dead code, identified by coverity and reported by Nuno
458        Lopes.
459    
460    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
461    
462        (1) The include/exclude patterns were being applied to the whole pathnames
463            of files, instead of just to the final components.
464    
465        (2) If there was more than one level of directory, the subdirectories were
466            skipped unless they satisfied the include/exclude conditions. This is
467            inconsistent with GNU grep (and could even be seen as contrary to the
468            pcregrep specification - which I improved to make it absolutely clear).
469            The action now is always to scan all levels of directory, and just
470            apply the include/exclude patterns to regular files.
471    
472    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
473        --exclude_dir in the tests to avoid scanning .svn directories.
474    
475    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
476        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
477        doesn't support NULs in patterns.
478    
479    7.  Added some missing "const"s to declarations of static tables in
480        pcre_compile.c and pcre_dfa_exec.c.
481    
482    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
483        caused by fix #2  above. (Subsequently also a second patch to fix the
484        first patch. And a third patch - this was a messy problem.)
485    
486    9.  Applied Craig's patch to remove the use of push_back().
487    
488    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
489        matching function regexec().
490    
491    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
492        which, however, unlike Perl's \g{...}, are subroutine calls, not back
493        references. PCRE supports relative numbers with this syntax (I don't think
494        Oniguruma does).
495    
496    12. Previously, a group with a zero repeat such as (...){0} was completely
497        omitted from the compiled regex. However, this means that if the group
498        was called as a subroutine from elsewhere in the pattern, things went wrong
499        (an internal error was given). Such groups are now left in the compiled
500        pattern, with a new opcode that causes them to be skipped at execution
501        time.
502    
503    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
504        to the way PCRE behaves:
505    
506        (a) A lone ] character is dis-allowed (Perl treats it as data).
507    
508        (b) A back reference to an unmatched subpattern matches an empty string
509            (Perl fails the current match path).
510    
511        (c) A data ] in a character class must be notated as \] because if the
512            first data character in a class is ], it defines an empty class. (In
513            Perl it is not possible to have an empty class.) The empty class []
514            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
515            The negative empty class [^] matches any one character, independently
516            of the DOTALL setting.
517    
518    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
519        non-existent subpattern following a character class starting with ']' and
520        containing () gave an internal compiling error instead of "reference to
521        non-existent subpattern". Fortunately, when the pattern did exist, the
522        compiled code was correct. (When scanning forwards to check for the
523        existencd of the subpattern, it was treating the data ']' as terminating
524        the class, so got the count wrong. When actually compiling, the reference
525        was subsequently set up correctly.)
526    
527    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
528        it was being rejected as not supported by pcre_dfa_exec(), even though
529        other assertions are supported. I have made pcre_dfa_exec() support
530        (*FAIL).
531    
532    16. The implementation of 13c above involved the invention of a new opcode,
533        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
534        cannot be changed at match time, I realized I could make a small
535        improvement to matching performance by compiling OP_ALLANY instead of
536        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
537        on the OP_ANY path.
538    
539    17. Compiling pcretest on Windows with readline support failed without the
540        following two fixes: (1) Make the unistd.h include conditional on
541        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
542    
543    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
544        ncurses library to be included for pcretest when ReadLine support is
545        requested, but also to allow for it to be overridden. This patch came from
546        Daniel Bergström.
547    
548    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
549        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
550        any errors with the current Unicode tables. Thanks to Peter Kankowski for
551        spotting this.
552    
553    
554    Version 7.6 28-Jan-08
555    ---------------------
556    
557    1.  A character class containing a very large number of characters with
558        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
559        overflow.
560    
561    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
562        HAVE_LONG_LONG is not defined.
563    
564    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
565        bring them up to date and include new features. This patch includes:
566    
567        - Fixed PH's badly added libz and libbz2 support.
568        - Fixed a problem with static linking.
569        - Added pcredemo. [But later removed - see 7 below.]
570        - Fixed dftables problem and added an option.
571        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
572            HAVE_LONG_LONG.
573        - Added readline support for pcretest.
574        - Added an listing of the option settings after cmake has run.
575    
576    4.  A user submitted a patch to Makefile that makes it easy to create
577        "pcre.dll" under mingw when using Configure/Make. I added stuff to
578        Makefile.am that cause it to include this special target, without
579        affecting anything else. Note that the same mingw target plus all
580        the other distribution libraries and programs are now supported
581        when configuring with CMake (see 6 below) instead of with
582        Configure/Make.
583    
584    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
585        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
586        exported in the Windows port". It has not yet been confirmed that the patch
587        solves the problem, but it does no harm.
588    
589    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
590        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
591        with CMake, and also correct the comment about stack recursion.
592    
593    7.  Remove the automatic building of pcredemo from the ./configure system and
594        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
595        of a program that users should build themselves after PCRE is installed, so
596        building it automatically is not really right. What is more, it gave
597        trouble in some build environments.
598    
599    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
600    
601    
602    Version 7.5 10-Jan-08
603    ---------------------
604    
605    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
606        values in parens when parsing an RE using the C++ wrapper."
607    
608    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
609        Characters greater than 255 were excluded from the class instead of being
610        included.
611    
612    3.  The same bug as (2) above applied to negated POSIX classes such as
613        [:^space:].
614    
615    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
616        defined or documented. It seems to have been a typo for PCRE_STATIC, so
617        I have changed it.
618    
619    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
620        first named subpattern) and a construct such as (?&a) would reference the
621        first named subpattern whose name started with "a" (in other words, the
622        length check was missing). Both these problems are fixed. "Subpattern name
623        expected" is now given for (?&) (a zero-length name), and this patch also
624        makes it give the same error for \k'' (previously it complained that that
625        was a reference to a non-existent subpattern).
626    
627    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
628        this is right because (?- can be followed by option settings as well as by
629        digits. I have, however, made the messages clearer.
630    
631    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
632        than the number used in the conditional) now cause a compile-time error.
633        This is actually not compatible with Perl, which accepts such patterns, but
634        treats the conditional as always being FALSE (as PCRE used to), but it
635        seems to me that giving a diagnostic is better.
636    
637    8.  Change "alphameric" to the more common word "alphanumeric" in comments
638        and messages.
639    
640    9.  Fix two occurrences of "backslash" in comments that should have been
641        "backspace".
642    
643    10. Remove two redundant lines of code that can never be obeyed (their function
644        was moved elsewhere).
645    
646    11. The program that makes PCRE's Unicode character property table had a bug
647        which caused it to generate incorrect table entries for sequences of
648        characters that have the same character type, but are in different scripts.
649        It amalgamated them into a single range, with the script of the first of
650        them. In other words, some characters were in the wrong script. There were
651        thirteen such cases, affecting characters in the following ranges:
652    
653          U+002b0 - U+002c1
654          U+0060c - U+0060d
655          U+0061e - U+00612
656          U+0064b - U+0065e
657          U+0074d - U+0076d
658          U+01800 - U+01805
659          U+01d00 - U+01d77
660          U+01d9b - U+01dbf
661          U+0200b - U+0200f
662          U+030fc - U+030fe
663          U+03260 - U+0327f
664          U+0fb46 - U+0fbb1
665          U+10450 - U+1049d
666    
667    12. The -o option (show only the matching part of a line) for pcregrep was not
668        compatible with GNU grep in that, if there was more than one match in a
669        line, it showed only the first of them. It now behaves in the same way as
670        GNU grep.
671    
672    13. If the -o and -v options were combined for pcregrep, it printed a blank
673        line for every non-matching line. GNU grep prints nothing, and pcregrep now
674        does the same. The return code can be used to tell if there were any
675        non-matching lines.
676    
677    14. Added --file-offsets and --line-offsets to pcregrep.
678    
679    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
680        infinitely looping recursion. The bug was that positive lookaheads were not
681        being skipped when checking for a possible empty match (negative lookaheads
682        and both kinds of lookbehind were skipped).
683    
684    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
685        inclusion of <windows.h> to before rather than after the definition of
686        INVALID_FILE_ATTRIBUTES (patch from David Byron).
687    
688    17. Specifying a possessive quantifier with a specific limit for a Unicode
689        character property caused pcre_compile() to compile bad code, which led at
690        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
691        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
692        caused the error; without that there was no problem.
693    
694    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
695    
696    19. Added --enable-pcretest-libreadline.
697    
698    20. In pcrecpp.cc, the variable 'count' was incremented twice in
699        RE::GlobalReplace(). As a result, the number of replacements returned was
700        double what it should be. I removed one of the increments, but Craig sent a
701        later patch that removed the other one (the right fix) and added unit tests
702        that check the return values (which was not done before).
703    
704    21. Several CMake things:
705    
706        (1) Arranged that, when cmake is used on Unix, the libraries end up with
707            the names libpcre and libpcreposix, not just pcre and pcreposix.
708    
709        (2) The above change means that pcretest and pcregrep are now correctly
710            linked with the newly-built libraries, not previously installed ones.
711    
712        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
713    
714    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
715        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
716        UTF-8 newline character). The key issue is that the pattern starts .*;
717        this means that the match must be either at the beginning, or after a
718        newline. The bug was in the code for advancing after a failed match and
719        checking that the new position followed a newline. It was not taking
720        account of UTF-8 characters correctly.
721    
722    23. PCRE was behaving differently from Perl in the way it recognized POSIX
723        character classes. PCRE was not treating the sequence [:...:] as a
724        character class unless the ... were all letters. Perl, however, seems to
725        allow any characters between [: and :], though of course it rejects as
726        unknown any "names" that contain non-letters, because all the known class
727        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
728        for example, whereas PCRE did not - it did not recognize a POSIX character
729        class. This seemed a bit dangerous, so the code has been changed to be
730        closer to Perl. The behaviour is not identical to Perl, because PCRE will
731        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
732        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
733        Perl does, and where it didn't before.
734    
735    24. Rewrite so as to remove the single use of %n from pcregrep because in some
736        Windows environments %n is disabled by default.
737    
738    
739    Version 7.4 21-Sep-07
740    ---------------------
741    
742    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
743        means that a class such as [\s] counted as "explicit reference to CR or
744        LF". That isn't really right - the whole point of the change was to try to
745        help when there was an actual mention of one of the two characters. So now
746        the change happens only if \r or \n (or a literal CR or LF) character is
747        encountered.
748    
749    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
750        of both had grown to the point where there were only 3 bits left.
751        Fortunately, there was spare space in the data structure, and so I have
752        moved the internal flags into a new 16-bit field to free up more option
753        bits.
754    
755    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
756        but did not set the internal JCHANGED flag - either of these is enough to
757        control the way the "get" function works - but the PCRE_INFO_JCHANGED
758        facility is supposed to tell if (?J) was ever used, so now (?J) at the
759        start sets both bits.
760    
761    4.  Added options (at build time, compile time, exec time) to change \R from
762        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
763    
764    5.  doc/pcresyntax.html was missing from the distribution.
765    
766    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
767        compatibility, even though it is no longer used.
768    
769    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
770        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
771        windows.h file is present (where different names are used). [This was
772        reversed later after testing - see 16 below.]
773    
774    8.  Changed all #include <config.h> to #include "config.h". There were also
775        some further <pcre.h> cases that I changed to "pcre.h".
776    
777    9.  When pcregrep was used with the --colour option, it missed the line ending
778        sequence off the lines that it output.
779    
780    10. It was pointed out to me that arrays of string pointers cause lots of
781        relocations when a shared library is dynamically loaded. A technique of
782        using a single long string with a table of offsets can drastically reduce
783        these. I have refactored PCRE in four places to do this. The result is
784        dramatic:
785    
786          Originally:                          290
787          After changing UCP table:            187
788          After changing error message table:   43
789          After changing table of "verbs"       36
790          After changing table of Posix names   22
791    
792        Thanks to the folks working on Gregex for glib for this insight.
793    
794    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
795        unicode-properties was also set.
796    
797    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
798    
799    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
800        checked only for CRLF.
801    
802    14. Added casts to pcretest.c to avoid compiler warnings.
803    
804    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
805    
806    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
807        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
808        entirely. This removes changes made in 7 above.
809    
810    17. The CMake files have been updated, and there is now more information about
811        building with CMake in the NON-UNIX-USE document.
812    
813    
814    Version 7.3 28-Aug-07
815    ---------------------
816    
817     1. In the rejigging of the build system that eventually resulted in 7.1, the
818        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
819        brackets there is not right, since it causes compilers to look for an
820        installed pcre.h, not the version that is in the source that is being
821        compiled (which of course may be different). I have changed it back to:
822    
823          #include "pcre.h"
824    
825        I have a vague recollection that the change was concerned with compiling in
826        different directories, but in the new build system, that is taken care of
827        by the VPATH setting the Makefile.
828    
829     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
830        when the subject happened to end in the byte 0x85 (e.g. if the last
831        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
832        characters but of course it shouldn't be taken as a newline when it is part
833        of another character. The bug was that, for an unlimited repeat of . in
834        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
835        characters when looking for a newline.
836    
837     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
838    
839     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
840        in debug output.
841    
842     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
843        long printing in the pcrecpp unittest when running under MinGW.
844    
845     6. ESC_K was left out of the EBCDIC table.
846    
847     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
848        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
849        limit also applies to "virtual nesting" when a pattern is recursive, and in
850        this case 1000 isn't so big. I have been able to remove this limit at the
851        expense of backing off one optimization in certain circumstances. Normally,
852        when pcre_exec() would call its internal match() function recursively and
853        immediately return the result unconditionally, it uses a "tail recursion"
854        feature to save stack. However, when a subpattern that can match an empty
855        string has an unlimited repetition quantifier, it no longer makes this
856        optimization. That gives it a stack frame in which to save the data for
857        checking that an empty string has been matched. Previously this was taken
858        from the 1000-entry workspace that had been reserved. So now there is no
859        explicit limit, but more stack is used.
860    
861     8. Applied Daniel's patches to solve problems with the import/export magic
862        syntax that is required for Windows, and which was going wrong for the
863        pcreposix and pcrecpp parts of the library. These were overlooked when this
864        problem was solved for the main library.
865    
866     9. There were some crude static tests to avoid integer overflow when computing
867        the size of patterns that contain repeated groups with explicit upper
868        limits. As the maximum quantifier is 65535, the maximum group length was
869        set at 30,000 so that the product of these two numbers did not overflow a
870        32-bit integer. However, it turns out that people want to use groups that
871        are longer than 30,000 bytes (though not repeat them that many times).
872        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
873        made it possible to implement the integer overflow checks in a much more
874        dynamic way, which I have now done. The artificial limitation on group
875        length has been removed - we now have only the limit on the total length of
876        the compiled pattern, which depends on the LINK_SIZE setting.
877    
878    10. Fixed a bug in the documentation for get/copy named substring when
879        duplicate names are permitted. If none of the named substrings are set, the
880        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
881        empty string.
882    
883    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
884        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
885        because the ] is interpreted as the first data character and the
886        terminating ] is not found. PCRE has been made compatible with Perl in this
887        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
888        cause memory overwriting.
889    
890    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
891        string has been matched (to stop an infinite loop). It was not recognizing
892        a conditional subpattern that could match an empty string if that
893        subpattern was within another subpattern. For example, it looped when
894        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
895        condition was not nested. This bug has been fixed.
896    
897    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
898        past the start of the subject in the presence of bytes with the top bit
899        set, for example "\x8aBCD".
900    
901    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
902        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
903    
904    14. Optimized (?!) to (*FAIL).
905    
906    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
907        This restricts code points to be within the range 0 to 0x10FFFF, excluding
908        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
909        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
910        does: it's just the validity check that is more restrictive.
911    
912    16. Inserted checks for integer overflows during escape sequence (backslash)
913        processing, and also fixed erroneous offset values for syntax errors during
914        backslash processing.
915    
916    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
917        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
918    
919    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
920        caused an overrun.
921    
922    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
923        something other than just ASCII characters) inside a group that had an
924        unlimited repeat caused a loop at compile time (while checking to see
925        whether the group could match an empty string).
926    
927    20. Debugging a pattern containing \p or \P could cause a crash. For example,
928        [\P{Any}] did so. (Error in the code for printing property names.)
929    
930    21. An orphan \E inside a character class could cause a crash.
931    
932    22. A repeated capturing bracket such as (A)? could cause a wild memory
933        reference during compilation.
934    
935    23. There are several functions in pcre_compile() that scan along a compiled
936        expression for various reasons (e.g. to see if it's fixed length for look
937        behind). There were bugs in these functions when a repeated \p or \P was
938        present in the pattern. These operators have additional parameters compared
939        with \d, etc, and these were not being taken into account when moving along
940        the compiled data. Specifically:
941    
942        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
943            length.
944    
945        (b) An item such as \pL+ within a repeated group could cause crashes or
946            loops.
947    
948        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
949            "reference to non-existent subpattern" error.
950    
951        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
952    
953    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
954        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
955    
956    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
957    
958    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
959        character were causing crashes (broken optimization).
960    
961    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
962        \p or \P) caused a compile-time loop.
963    
964    28. More problems have arisen in unanchored patterns when CRLF is a valid line
965        break. For example, the unstudied pattern [\r\n]A does not match the string
966        "\r\nA" because change 7.0/46 below moves the current point on by two
967        characters after failing to match at the start. However, the pattern \nA
968        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
969        the same is true. There doesn't seem any very clean way out of this, but
970        what I have chosen to do makes the common cases work: PCRE now takes note
971        of whether there can be an explicit match for \r or \n anywhere in the
972        pattern, and if so, 7.0/46 no longer applies. As part of this change,
973        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
974        pattern has explicit CR or LF references.
975    
976    29. Added (*CR) etc for changing newline setting at start of pattern.
977    
978    
979    Version 7.2 19-Jun-07
980    ---------------------
981    
982     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
983        which is apparently normally available under Windows.
984    
985     2. Re-jig the pcregrep tests with different newline settings in an attempt
986        to make them independent of the local environment's newline setting.
987    
988     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
989    
990     4. Some of the "internals" tests were previously cut out when the link size
991        was not 2, because the output contained actual offsets. The recent new
992        "Z" feature of pcretest means that these can be cut out, making the tests
993        usable with all link sizes.
994    
995     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
996        stack recursion. This gives a massive performance boost under BSD, but just
997        a small improvement under Linux. However, it saves one field in the frame
998        in all cases.
999    
1000     6. Added more features from the forthcoming Perl 5.10:
1001    
1002        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1003            recursion call. It refers to the nth most recently opened parentheses.
1004    
1005        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1006            to be opened parentheses.
1007    
1008        (c) Conditions that refer to capturing parentheses can be specified
1009            relatively, for example, (?(-2)... or (?(+3)...
1010    
1011        (d) \K resets the start of the current match so that everything before
1012            is not part of it.
1013    
1014        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1015    
1016        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1017            reference syntax.
1018    
1019        (g) (?| introduces a group in which the numbering of parentheses in each
1020            alternative starts with the same number.
1021    
1022        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1023    
1024     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1025        PCRE_INFO_JCHANGED.
1026    
1027     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1028        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1029        for detecting groups that can match an empty string.
1030    
1031     9. A pattern with a very large number of alternatives (more than several
1032        hundred) was running out of internal workspace during the pre-compile
1033        phase, where pcre_compile() figures out how much memory will be needed. A
1034        bit of new cunning has reduced the workspace needed for groups with
1035        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1036        workspace instead of running out of the 4096 that are available.
1037    
1038    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1039    
1040    11. Applied patch from Google to remove an optimization that didn't quite work.
1041        The report of the bug said:
1042    
1043          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1044          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1045          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1046    
1047    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1048        it matched the wrong number of bytes.
1049    
1050    
1051    Version 7.1 24-Apr-07
1052    ---------------------
1053    
1054     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1055        that is more "standard", making use of automake and other Autotools. There
1056        is some re-arrangement of the files and adjustment of comments consequent
1057        on this.
1058    
1059     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1060        for recursive directory scanning broke on some systems because the files
1061        are not scanned in any specific order and on different systems the order
1062        was different. A call to "sort" has been inserted into RunGrepTest for the
1063        approprate test as a short-term fix. In the longer term there may be an
1064        alternative.
1065    
1066     3. I had an email from Eric Raymond about problems translating some of PCRE's
1067        man pages to HTML (despite the fact that I distribute HTML pages, some
1068        people do their own conversions for various reasons). The problems
1069        concerned the use of low-level troff macros .br and .in. I have therefore
1070        removed all such uses from the man pages (some were redundant, some could
1071        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1072        HTML has been updated to handle .nf/.fi and to complain if it encounters
1073        .br or .in.
1074    
1075     4. Updated comments in configure.ac that get placed in config.h.in and also
1076        arranged for config.h to be included in the distribution, with the name
1077        config.h.generic, for the benefit of those who have to compile without
1078        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1079    
1080     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1081        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1082        makevp.bat for the current PCRE, using the additional files
1083        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1084    
1085     6. A Windows user reported a minor discrepancy with test 2, which turned out
1086        to be caused by a trailing space on an input line that had got lost in his
1087        copy. The trailing space was an accident, so I've just removed it.
1088    
1089     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1090        that is needed.
1091    
1092     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1093        as "const" (a) because they are and (b) because it helps the PHP
1094        maintainers who have recently made a script to detect big data structures
1095        in the php code that should be moved to the .rodata section. I remembered
1096        to update Builducptable as well, so it won't revert if ucptable.h is ever
1097        re-created.
1098    
1099     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1100        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1101        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1102        support is not required. This saves 1.5-2K of code, which is important in
1103        some applications.
1104    
1105        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1106        so as not to refer to the tables, even though these functions will never be
1107        called when UTF-8 support is disabled. Otherwise there are problems with a
1108        shared library.
1109    
1110    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1111    
1112        (a) It was defining its arguments as char * instead of void *.
1113    
1114        (b) It was assuming that all moves were upwards in memory; this was true
1115            a long time ago when I wrote it, but is no longer the case.
1116    
1117        The emulated memove() is provided for those environments that have neither
1118        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1119        is clearly not the case, as these two bugs were recently reported.
1120    
1121    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1122        and Detrail to create the HTML documentation, the .txt form of the man
1123        pages, and it removes trailing spaces from listed files. It also creates
1124        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1125        case, it wraps all the #defines with #ifndefs. This script should be run
1126        before "make dist".
1127    
1128    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1129        with Unicode property support.
1130    
1131        (a) For a maximizing quantifier, if the two different cases of the
1132            character were of different lengths in their UTF-8 codings (there are
1133            some cases like this - I found 11), and the matching function had to
1134            back up over a mixture of the two cases, it incorrectly assumed they
1135            were both the same length.
1136    
1137        (b) When PCRE was configured to use the heap rather than the stack for
1138            recursion during matching, it was not correctly preserving the data for
1139            the other case of a UTF-8 character when checking ahead for a match
1140            while processing a minimizing repeat. If the check also involved
1141            matching a wide character, but failed, corruption could cause an
1142            erroneous result when trying to check for a repeat of the original
1143            character.
1144    
1145    13. Some tidying changes to the testing mechanism:
1146    
1147        (a) The RunTest script now detects the internal link size and whether there
1148            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1149            values substituted by "configure". (The RunGrepTest script already did
1150            this for UTF-8.) The configure.ac script no longer substitutes the
1151            relevant variables.
1152    
1153        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1154            with length and offset values. This means that the output is different
1155            for different internal link sizes. Test 2 is skipped for link sizes
1156            other than 2 because of this, bypassing the problem. Unfortunately,
1157            there was also a test in test 3 (the locale tests) that used /B and
1158            failed for link sizes other than 2. Rather than cut the whole test out,
1159            I have added a new /Z option to pcretest that replaces the length and
1160            offset values with spaces. This is now used to make test 3 independent
1161            of link size. (Test 2 will be tidied up later.)
1162    
1163    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1164        segmentation fault instead of returning the appropriate error message.
1165    
1166    15. In multiline mode when the newline sequence was set to "any", the pattern
1167        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1168        This doesn't seem right; it now treats the CRLF combination as the line
1169        ending, and so does not match in that case. It's only a pattern such as ^$
1170        that would hit this one: something like ^ABC$ would have failed after \r
1171        and then tried again after \r\n.
1172    
1173    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1174        in an attempt to make files that differ only in their line terminators
1175        compare equal. This works on Linux.
1176    
1177    17. Under certain error circumstances pcregrep might try to free random memory
1178        as it exited. This is now fixed, thanks to valgrind.
1179    
1180    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1181        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1182        was because its rules for how to advance for /g after matching an empty
1183        string at the end of a line did not allow for this case. They now check for
1184        it specially.
1185    
1186    20. pcretest is supposed to handle patterns and data of any length, by
1187        extending its buffers when necessary. It was getting this wrong when the
1188        buffer for a data line had to be extended.
1189    
1190    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1191        CRLF as a newline sequence.
1192    
1193    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1194        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1195        I have nevertheless tidied it up.
1196    
1197    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1198    
1199    24. Added a man page for pcre-config.
1200    
1201    
1202    Version 7.0 19-Dec-06
1203    ---------------------
1204    
1205     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1206        moving to gcc 4.1.1.
1207    
1208     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1209        sys/time.h, which is documented as needed for this function. It doesn't
1210        seem to matter on Linux, but it showed up on some releases of OS X.
1211    
1212     3. It seems that there are systems where bytes whose values are greater than
1213        127 match isprint() in the "C" locale. The "C" locale should be the
1214        default when a C program starts up. In most systems, only ASCII printing
1215        characters match isprint(). This difference caused the output from pcretest
1216        to vary, making some of the tests fail. I have changed pcretest so that:
1217    
1218        (a) When it is outputting text in the compiled version of a pattern, bytes
1219            other than 32-126 are always shown as hex escapes.
1220    
1221        (b) When it is outputting text that is a matched part of a subject string,
1222            it does the same, unless a different locale has been set for the match
1223            (using the /L modifier). In this case, it uses isprint() to decide.
1224    
1225     4. Fixed a major bug that caused incorrect computation of the amount of memory
1226        required for a compiled pattern when options that changed within the
1227        pattern affected the logic of the preliminary scan that determines the
1228        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1229        that the computed length was too small. The symptoms of this bug were
1230        either the PCRE error "internal error: code overflow" from pcre_compile(),
1231        or a glibc crash with a message such as "pcretest: free(): invalid next
1232        size (fast)". Examples of patterns that provoked this bug (shown in
1233        pcretest format) are:
1234    
1235          /(?-x: )/x
1236          /(?x)(?-x: \s*#\s*)/
1237          /((?i)[\x{c0}])/8
1238          /(?i:[\x{c0}])/8
1239    
1240        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1241        is now done differently.
1242    
1243     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1244        wrapper classes; (b) implement a new function in the C++ scanner that is
1245        more efficient than the old way of doing things because it avoids levels of
1246        recursion in the regex matching; (c) add a paragraph to the documentation
1247        for the FullMatch() function.
1248    
1249     6. The escape sequence \n was being treated as whatever was defined as
1250        "newline". Not only was this contrary to the documentation, which states
1251        that \n is character 10 (hex 0A), but it also went horribly wrong when
1252        "newline" was defined as CRLF. This has been fixed.
1253    
1254     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1255        was being set to -1 for the "end of line" case (supposedly a value that no
1256        character can have). Though this value is never used (the check for end of
1257        line is "zero bytes in current character"), it caused compiler complaints.
1258        I've changed it to 0xffffffff.
1259    
1260     8. In pcre_version.c, the version string was being built by a sequence of
1261        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1262        string (as it is for production releases) called a macro with an empty
1263        argument. The C standard says the result of this is undefined. The gcc
1264        compiler treats it as an empty string (which was what was wanted) but it is
1265        reported that Visual C gives an error. The source has been hacked around to
1266        avoid this problem.
1267    
1268     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1269        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1270        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1271        of them did).
1272    
1273    10. Originally, pcretest opened its input and output without "b"; then I was
1274        told that "b" was needed in some environments, so it was added for release
1275        5.0 to both the input and output. (It makes no difference on Unix-like
1276        systems.) Later I was told that it is wrong for the input on Windows. I've
1277        now abstracted the modes into two macros, to make it easier to fiddle with
1278        them, and removed "b" from the input mode under Windows.
1279    
1280    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1281    
1282    12. Added -help and --help to pcretest as an official way of being reminded
1283        of the options.
1284    
1285    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1286        and pcrecpp.cc because they annoy compilers at high warning levels.
1287    
1288    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1289    
1290    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1291        scripts are not C programs :-) and which was not noticed because it works
1292        on Linux.
1293    
1294    16. pcretest is supposed to handle any length of pattern and data line (as one
1295        line or as a continued sequence of lines) by extending its input buffer if
1296        necessary. This feature was broken for very long pattern lines, leading to
1297        a string of junk being passed to pcre_compile() if the pattern was longer
1298        than about 50K.
1299    
1300    17. I have done a major re-factoring of the way pcre_compile() computes the
1301        amount of memory needed for a compiled pattern. Previously, there was code
1302        that made a preliminary scan of the pattern in order to do this. That was
1303        OK when PCRE was new, but as the facilities have expanded, it has become
1304        harder and harder to keep it in step with the real compile phase, and there
1305        have been a number of bugs (see for example, 4 above). I have now found a
1306        cunning way of running the real compile function in a "fake" mode that
1307        enables it to compute how much memory it would need, while actually only
1308        ever using a few hundred bytes of working memory and without too many
1309        tests of the mode. This should make future maintenance and development
1310        easier. A side effect of this work is that the limit of 200 on the nesting
1311        depth of parentheses has been removed (though this was never a serious
1312        limitation, I suspect). However, there is a downside: pcre_compile() now
1313        runs more slowly than before (30% or more, depending on the pattern). I
1314        hope this isn't a big issue. There is no effect on runtime performance.
1315    
1316    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1317        newline (only possible for the last line of a file) and it was a
1318        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1319    
1320    19. Added additional timing features to pcretest. (1) The -tm option now times
1321        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1322        separate command line item, by a number that specifies the number of
1323        repeats to use when timing. The default is 50000; this gives better
1324        precision, but takes uncomfortably long for very large patterns.
1325    
1326    20. Extended pcre_study() to be more clever in cases where a branch of a
1327        subpattern has no definite first character. For example, (a*|b*)[cd] would
1328        previously give no result from pcre_study(). Now it recognizes that the
1329        first character must be a, b, c, or d.
1330    
1331    21. There was an incorrect error "recursive call could loop indefinitely" if
1332        a subpattern (or the entire pattern) that was being tested for matching an
1333        empty string contained only one non-empty item after a nested subpattern.
1334        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1335        incorrectly, because the \d was being skipped in the check.
1336    
1337    22. The pcretest program now has a new pattern option /B and a command line
1338        option -b, which is equivalent to adding /B to every pattern. This causes
1339        it to show the compiled bytecode, without the additional information that
1340        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1341        is the same as /B/I).
1342    
1343    23. A new optimization is now able automatically to treat some sequences such
1344        as a*b as a*+b. More specifically, if something simple (such as a character
1345        or a simple class like \d) has an unlimited quantifier, and is followed by
1346        something that cannot possibly match the quantified thing, the quantifier
1347        is automatically "possessified".
1348    
1349    24. A recursive reference to a subpattern whose number was greater than 39
1350        went wrong under certain circumstances in UTF-8 mode. This bug could also
1351        have affected the operation of pcre_study().
1352    
1353    25. Realized that a little bit of performance could be had by replacing
1354        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1355    
1356    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1357    
1358    27. Possessive quantifiers such as a++ were previously implemented by turning
1359        them into atomic groups such as ($>a+). Now they have their own opcodes,
1360        which improves performance. This includes the automatically created ones
1361        from 23 above.
1362    
1363    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1364        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1365        the first matched character to be a colon. This applied both to named and
1366        numbered groups.
1367    
1368    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1369    
1370    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1371        building PCRE on Windows easier, so I have included it in the distribution.
1372    
1373    31. There is now a check in pcretest against a ridiculously large number being
1374        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1375        loop, the loop is abandoned.
1376    
1377    32. Forward references to subpatterns in conditions such as (?(2)...) where
1378        subpattern 2 is defined later cause pcre_compile() to search forwards in
1379        the pattern for the relevant set of parentheses. This search went wrong
1380        when there were unescaped parentheses in a character class, parentheses
1381        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1382    
1383    33. "Subroutine" calls and backreferences were previously restricted to
1384        referencing subpatterns earlier in the regex. This restriction has now
1385        been removed.
1386    
1387    34. Added a number of extra features that are going to be in Perl 5.10. On the
1388        whole, these are just syntactic alternatives for features that PCRE had
1389        previously implemented using the Python syntax or my own invention. The
1390        other formats are all retained for compatibility.
1391    
1392        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1393            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1394            also .NET compatible.
1395    
1396        (b) A recursion or subroutine call to a named group can now be defined as
1397            (?&name) as well as (?P>name).
1398    
1399        (c) A backreference to a named group can now be defined as \k<name> or
1400            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1401            5.10, are also .NET compatible.
1402    
1403        (d) A conditional reference to a named group can now use the syntax
1404            (?(<name>) or (?('name') as well as (?(name).
1405    
1406        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1407            groups (named and numbered) that are never evaluated inline, but can be
1408            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1409            is always false. There may be only one alternative in such a group.
1410    
1411        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1412            as the simple (?(R). The condition is true only if the most recent
1413            recursion is that of the given number or name. It does not search out
1414            through the entire recursion stack.
1415    
1416        (g) The escape \gN or \g{N} has been added, where N is a positive or
1417            negative number, specifying an absolute or relative reference.
1418    
1419    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1420        some "unreachable code" warnings.
1421    
1422    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1423        things, this adds five new scripts.
1424    
1425    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1426        There were also incompatibilities regarding the handling of \Q..\E inside
1427        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1428        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1429    
1430    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1431        matches an empty string, and forcibly breaks the loop. There were bugs in
1432        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1433        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1434        separate and independent bugs (that affected different cases) have been
1435        fixed.
1436    
1437    39. Refactored the code to abolish the use of different opcodes for small
1438        capturing bracket numbers. This is a tidy that I avoided doing when I
1439        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1440        The new approach is not only tidier, it makes it possible to reduce the
1441        memory needed to fix the previous bug (38).
1442    
1443    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1444        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1445        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1446        mode.
1447    
1448    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1449        report.
1450    
1451    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1452        copy construction and assignment in the C++ wrapper.
1453    
1454    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1455        couple of bugs that could have given wrong results in the "--newline=crlf"
1456        case.
1457    
1458    44. Added a number of casts and did some reorganization of signed/unsigned int
1459        variables following suggestions from Dair Grant. Also renamed the variable
1460        "this" as "item" because it is a C++ keyword.
1461    
1462    45. Arranged for dftables to add
1463    
1464          #include "pcre_internal.h"
1465    
1466        to pcre_chartables.c because without it, gcc 4.x may remove the array
1467        definition from the final binary if PCRE is built into a static library and
1468        dead code stripping is activated.
1469    
1470    46. For an unanchored pattern, if a match attempt fails at the start of a
1471        newline sequence, and the newline setting is CRLF or ANY, and the next two
1472        characters are CRLF, advance by two characters instead of one.
1473    
1474    
1475    Version 6.7 04-Jul-06
1476    ---------------------
1477    
1478     1. In order to handle tests when input lines are enormously long, pcretest has
1479        been re-factored so that it automatically extends its buffers when
1480        necessary. The code is crude, but this _is_ just a test program. The
1481        default size has been increased from 32K to 50K.
1482    
1483     2. The code in pcre_study() was using the value of the re argument before
1484        testing it for NULL. (Of course, in any sensible call of the function, it
1485        won't be NULL.)
1486    
1487     3. The memmove() emulation function in pcre_internal.h, which is used on
1488        systems that lack both memmove() and bcopy() - that is, hardly ever -
1489        was missing a "static" storage class specifier.
1490    
1491     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1492        containing an extended class (one that cannot be represented by a bitmap
1493        because it contains high-valued characters or Unicode property items, e.g.
1494        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1495        pattern, but PCRE should not loop if you do not (it no longer does).
1496        [Detail: two cases were found: (a) a repeated subpattern containing an
1497        extended class; (b) a recursive reference to a subpattern that followed a
1498        previous extended class. It wasn't skipping over the extended class
1499        correctly when UTF-8 mode was not set.]
1500    
1501     5. A negated single-character class was not being recognized as fixed-length
1502        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1503        compile error "lookbehind assertion is not fixed length".
1504    
1505     6. The RunPerlTest auxiliary script was showing an unexpected difference
1506        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1507        write a Perl script that can interpret lines of an input file either as
1508        byte characters or as UTF-8, which is what "perltest" was being required to
1509        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1510        can't do is switch easily at run time between having the "use utf8;" pragma
1511        or not. In the end, I fudged it by using the RunPerlTest script to insert
1512        "use utf8;" explicitly for the UTF-8 tests.
1513    
1514     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1515        the end of the subject string, contrary to the documentation and to what
1516        Perl does. This was true of both matching functions. Now it matches only at
1517        the start of the subject and immediately after *internal* newlines.
1518    
1519     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1520        a pointer to an int instead of a pointer to an unsigned long int. This
1521        caused problems on 64-bit systems.
1522    
1523     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1524        instance of the 'standard' template library not being so standard".
1525    
1526    10. There was no check on the number of named subpatterns nor the maximum
1527        length of a subpattern name. The product of these values is used to compute
1528        the size of the memory block for a compiled pattern. By supplying a very
1529        long subpattern name and a large number of named subpatterns, the size
1530        computation could be caused to overflow. This is now prevented by limiting
1531        the length of names to 32 characters, and the number of named subpatterns
1532        to 10,000.
1533    
1534    11. Subpatterns that are repeated with specific counts have to be replicated in
1535        the compiled pattern. The size of memory for this was computed from the
1536        length of the subpattern and the repeat count. The latter is limited to
1537        65535, but there was no limit on the former, meaning that integer overflow
1538        could in principle occur. The compiled length of a repeated subpattern is
1539        now limited to 30,000 bytes in order to prevent this.
1540    
1541    12. Added the optional facility to have named substrings with the same name.
1542    
1543    13. Added the ability to use a named substring as a condition, using the
1544        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1545        are numbers (not recommended). Forward references are permitted.
1546    
1547    14. Added forward references in named backreferences (if you see what I mean).
1548    
1549    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1550        pattern could run off the end of the subject. For example, the pattern
1551        "(?s)(.{1,5})"8 did this with the subject "ab".
1552    
1553    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1554        PCRE_CASELESS was set when matching characters that were quantified with ?
1555        or *.
1556    
1557    17. A character class other than a single negated character that had a minimum
1558        but no maximum quantifier - for example [ab]{6,} - was not handled
1559        correctly by pce_dfa_exec(). It would match only one character.
1560    
1561    18. A valid (though odd) pattern that looked like a POSIX character
1562        class but used an invalid character after [ (for example [[,abc,]]) caused
1563        pcre_compile() to give the error "Failed: internal error: code overflow" or
1564        in some cases to crash with a glibc free() error. This could even happen if
1565        the pattern terminated after [[ but there just happened to be a sequence of
1566        letters, a binary zero, and a closing ] in the memory that followed.
1567    
1568    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1569        over the years. Originally (before any Unicode support), just the bottom 8
1570        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1571        output from "man perlunicode" includes this:
1572    
1573          The regular expression compiler produces polymorphic opcodes.  That
1574          is, the pattern adapts to the data and automatically switches to
1575          the Unicode character scheme when presented with Unicode data--or
1576          instead uses a traditional byte scheme when presented with byte
1577          data.
1578    
1579        Sadly, a wide octal escape does not cause a switch, and in a string with
1580        no other multibyte characters, these octal escapes are treated as before.
1581        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1582        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1583        Unicode string.
1584    
1585        I have not perpetrated such confusion in PCRE. Up till now, it took just
1586        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1587        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1588        translate to the appropriate multibyte character.
1589    
1590    29. Applied some refactoring to reduce the number of warnings from Microsoft
1591        and Borland compilers. This has included removing the fudge introduced
1592        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1593        a warning about an unused variable.
1594    
1595    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1596        characters since release 4.0, because Perl (from release 5.004) does not.
1597        [Or at least, is documented not to: some releases seem to be in conflict
1598        with the documentation.] However, when a pattern was studied with
1599        pcre_study() and all its branches started with \s, PCRE still included VT
1600        as a possible starting character. Of course, this did no harm; it just
1601        caused an unnecessary match attempt.
1602    
1603    22. Removed a now-redundant internal flag bit that recorded the fact that case
1604        dependency changed within the pattern. This was once needed for "required
1605        byte" processing, but is no longer used. This recovers a now-scarce options
1606        bit. Also moved the least significant internal flag bit to the most-
1607        significant bit of the word, which was not previously used (hangover from
1608        the days when it was an int rather than a uint) to free up another bit for
1609        the future.
1610    
1611    23. Added support for CRLF line endings as well as CR and LF. As well as the
1612        default being selectable at build time, it can now be changed at runtime
1613        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1614        specify that it is scanning data with non-default line endings.
1615    
1616    24. Changed the definition of CXXLINK to make it agree with the definition of
1617        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1618    
1619    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1620        recursions. This makes a big different to stack usage for some patterns.
1621    
1622    26. If a subpattern containing a named recursion or subroutine reference such
1623        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1624        the space required for the compiled pattern went wrong and gave too small a
1625        value. Depending on the environment, this could lead to "Failed: internal
1626        error: code overflow at offset 49" or "glibc detected double free or
1627        corruption" errors.
1628    
1629    27. Applied patches from Google (a) to support the new newline modes and (b) to
1630        advance over multibyte UTF-8 characters in GlobalReplace.
1631    
1632    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1633        difference for some implementation of PCRE in some Windows version.
1634    
1635    29. Added some extra testing facilities to pcretest:
1636    
1637        \q<number>   in a data line sets the "match limit" value
1638        \Q<number>   in a data line sets the "match recursion limt" value
1639        -S <number>  sets the stack size, where <number> is in megabytes
1640    
1641        The -S option isn't available for Windows.
1642    
1643    
1644    Version 6.6 06-Feb-06
1645    ---------------------
1646    
1647     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1648        in pcreposix.h. I have copied the definition from pcre.h.
1649    
1650     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1651        because pcre.h is no longer a built file.
1652    
1653     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1654        not normally included in the compiled code.
1655    
1656    
1657    Version 6.5 01-Feb-06
1658    ---------------------
1659    
1660     1. When using the partial match feature with pcre_dfa_exec(), it was not
1661        anchoring the second and subsequent partial matches at the new starting
1662        point. This could lead to incorrect results. For example, with the pattern
1663        /1234/, partially matching against "123" and then "a4" gave a match.
1664    
1665     2. Changes to pcregrep:
1666    
1667        (a) All non-match returns from pcre_exec() were being treated as failures
1668            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1669            error message is output. Some extra information is given for the
1670            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1671            probably the only errors that are likely to be caused by users (by
1672            specifying a regex that has nested indefinite repeats, for instance).
1673            If there are more than 20 of these errors, pcregrep is abandoned.
1674    
1675        (b) A binary zero was treated as data while matching, but terminated the
1676            output line if it was written out. This has been fixed: binary zeroes
1677            are now no different to any other data bytes.
1678    
1679        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1680            used to set a locale for matching. The --locale=xxxx long option has
1681            been added (no short equivalent) to specify a locale explicitly on the
1682            pcregrep command, overriding the environment variables.
1683    
1684        (d) When -B was used with -n, some line numbers in the output were one less
1685            than they should have been.
1686    
1687        (e) Added the -o (--only-matching) option.
1688    
1689        (f) If -A or -C was used with -c (count only), some lines of context were
1690            accidentally printed for the final match.
1691    
1692        (g) Added the -H (--with-filename) option.
1693    
1694        (h) The combination of options -rh failed to suppress file names for files
1695            that were found from directory arguments.
1696    
1697        (i) Added the -D (--devices) and -d (--directories) options.
1698    
1699        (j) Added the -F (--fixed-strings) option.
1700    
1701        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1702    
1703        (l) Added the --colo(u)r option.
1704    
1705        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1706            is not present by default.
1707    
1708     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1709        items such as (?R) or (?1), when the recursion could match a number of
1710        alternatives. If it matched one of the alternatives, but subsequently,
1711        outside the recursion, there was a failure, the code tried to back up into
1712        the recursion. However, because of the way PCRE is implemented, this is not
1713        possible, and the result was an incorrect result from the match.
1714    
1715        In order to prevent this happening, the specification of recursion has
1716        been changed so that all such subpatterns are automatically treated as
1717        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1718    
1719     4. I had overlooked the fact that, in some locales, there are characters for
1720        which isalpha() is true but neither isupper() nor islower() are true. In
1721        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1722        and ordfeminine) are like this. This affected the treatment of \w and \W
1723        when they appeared in character classes, but not when they appeared outside
1724        a character class. The bit map for "word" characters is now created
1725        separately from the results of isalnum() instead of just taking it from the
1726        upper, lower, and digit maps. (Plus the underscore character, of course.)
1727    
1728     5. The above bug also affected the handling of POSIX character classes such as
1729        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1730        permanent tables. Instead, the bit maps for such a class were previously
1731        created as the appropriate unions of the upper, lower, and digit bitmaps.
1732        Now they are created by subtraction from the [[:word:]] class, which has
1733        its own bitmap.
1734    
1735     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1736        It is created by subtracting the vertical space characters (\x09, \x0a,
1737        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1738        subtraction was done in the overall bitmap for a character class, meaning
1739        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1740        be recognized. This bug has been fixed.
1741    
1742     7. Patches from the folks at Google:
1743    
1744          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1745          real life, but is still worth protecting against".
1746    
1747          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1748          regular expressions".
1749    
1750          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1751          have it.
1752    
1753          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1754          "configure" and the latter not, in order to fix a problem somebody had
1755          with compiling the Arg class on HP-UX.
1756    
1757          (e) Improve the error-handling of the C++ wrapper a little bit.
1758    
1759          (f) New tests for checking recursion limiting.
1760    
1761     8. The pcre_memmove() function, which is used only if the environment does not
1762        have a standard memmove() function (and is therefore rarely compiled),
1763        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1764        returning a result (though PCRE never actually uses the result).
1765    
1766     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1767        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1768        returned instead of calling malloc() with an overflowing number that would
1769        most likely cause subsequent chaos.
1770    
1771    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1772    
1773    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1774        with this option is matched, the nmatch and pmatch options of regexec() are
1775        ignored.
1776    
1777    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1778        provided in case anyone wants to the the POSIX interface with UTF-8
1779        strings.
1780    
1781    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1782        C++ linking (needed for some HP-UX environments).
1783    
1784    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1785        (unused parameter) and in the pcre_printint() function (omitted "default"
1786        switch label when the default is to do nothing).
1787    
1788    15. Added some code to make it possible, when PCRE is compiled as a C++
1789        library, to replace subject pointers for pcre_exec() with a smart pointer
1790        class, thus making it possible to process discontinuous strings.
1791    
1792    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1793        much the same function. They were added by different people who were trying
1794        to make PCRE easy to compile on non-Unix systems. It has been suggested
1795        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1796        for compiling on Windows systems. I have therefore replaced it with
1797        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1798        defaults to "extern" for C or "extern C" for C++, which works fine on
1799        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1800        SCOPE with something explicit in config.h. In addition:
1801    
1802        (a) pcreposix.h still had just "extern" instead of either of these macros;
1803            I have replaced it with PCRE_DATA_SCOPE.
1804    
1805        (b) Functions such as _pcre_xclass(), which are internal to the library,
1806            but external in the C sense, all had PCRE_EXPORT in their definitions.
1807            This is apparently wrong for the Windows case, so I have removed it.
1808            (It makes no difference on Unix-like systems.)
1809    
1810    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1811        of recursive calls to match(). This is different to MATCH_LIMIT because
1812        that limits the total number of calls to match(), not all of which increase
1813        the depth of recursion. Limiting the recursion depth limits the amount of
1814        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1815        when PCRE is compiled, and changed at run time. A patch from Google adds
1816        this functionality to the C++ interface.
1817    
1818    18. Changes to the handling of Unicode character properties:
1819    
1820        (a) Updated the table to Unicode 4.1.0.
1821    
1822        (b) Recognize characters that are not in the table as "Cn" (undefined).
1823    
1824        (c) I revised the way the table is implemented to a much improved format
1825            which includes recognition of ranges. It now supports the ranges that
1826            are defined in UnicodeData.txt, and it also amalgamates other
1827            characters into ranges. This has reduced the number of entries in the
1828            table from around 16,000 to around 3,000, thus reducing its size
1829            considerably. I realized I did not need to use a tree structure after
1830            all - a binary chop search is just as efficient. Having reduced the
1831            number of entries, I extended their size from 6 bytes to 8 bytes to
1832            allow for more data.
1833    
1834        (d) Added support for Unicode script names via properties such as \p{Han}.
1835    
1836    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1837        matching that character.
1838    
1839    20. When matching a repeated Unicode property with a minimum greater than zero,
1840        (for example \pL{2,}), PCRE could look past the end of the subject if it
1841        reached it while seeking the minimum number of characters. This could
1842        happen only if some of the characters were more than one byte long, because
1843        there is a check for at least the minimum number of bytes.
1844    
1845    21. Refactored the implementation of \p and \P so as to be more general, to
1846        allow for more different types of property in future. This has changed the
1847        compiled form incompatibly. Anybody with saved compiled patterns that use
1848        \p or \P will have to recompile them.
1849    
1850    22. Added "Any" and "L&" to the supported property types.
1851    
1852    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1853        but give a compile time error if the value is greater than 0xff.
1854    
1855    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1856        accidentally not being installed or uninstalled.
1857    
1858    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1859        made were to insert the current release number. This seemed silly, because
1860        it made things harder for people building PCRE on systems that don't run
1861        "configure". I have turned pcre.h into a distributed file, no longer built
1862        by "configure", with the version identification directly included. There is
1863        no longer a pcre.h.in file.
1864    
1865        However, this change necessitated a change to the pcre-config script as
1866        well. It is built from pcre-config.in, and one of the substitutions was the
1867        release number. I have updated configure.ac so that ./configure now finds
1868        the release number by grepping pcre.h.
1869    
1870    26. Added the ability to run the tests under valgrind.
1871    
1872    
1873    Version 6.4 05-Sep-05
1874    ---------------------
1875    
1876     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1877        "--" to be printed when multiple files were scanned, even when none of the
1878        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1879        consider it to be a bug, and have restored the previous behaviour.
1880    
1881     2. A couple of code tidies to get rid of compiler warnings.
1882    
1883     3. The pcretest program used to cheat by referring to symbols in the library
1884        whose names begin with _pcre_. These are internal symbols that are not
1885        really supposed to be visible externally, and in some environments it is
1886        possible to suppress them. The cheating is now confined to including
1887        certain files from the library's source, which is a bit cleaner.
1888    
1889     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1890        file's purpose clearer.
1891    
1892     5. Reorganized pcre_ucp_findchar().
1893    
1894    
1895    Version 6.3 15-Aug-05
1896    ---------------------
1897    
1898     1. The file libpcre.pc.in did not have general read permission in the tarball.
1899    
1900     2. There were some problems when building without C++ support:
1901    
1902        (a) If C++ support was not built, "make install" and "make test" still
1903            tried to test it.
1904    
1905        (b) There were problems when the value of CXX was explicitly set. Some
1906            changes have been made to try to fix these, and ...
1907    
1908        (c) --disable-cpp can now be used to explicitly disable C++ support.
1909    
1910        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1911            backslash in a target when C++ was disabled. This confuses some
1912            versions of "make", apparently. Using an intermediate variable solves
1913            this. (Same for CPP_LOBJ.)
1914    
1915     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1916        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1917        necessary on certain architectures.
1918    
1919     4. Added a setting of -export-symbols-regex to the link command to remove
1920        those symbols that are exported in the C sense, but actually are local
1921        within the library, and not documented. Their names all begin with
1922        "_pcre_". This is not a perfect job, because (a) we have to except some
1923        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1924        available (and never for static libraries). I have made a note to try to
1925        find a way round (a) in the future.
1926    
1927    
1928    Version 6.2 01-Aug-05
1929    ---------------------
1930    
1931     1. There was no test for integer overflow of quantifier values. A construction
1932        such as {1111111111111111} would give undefined results. What is worse, if
1933        a minimum quantifier for a parenthesized subpattern overflowed and became
1934        negative, the calculation of the memory size went wrong. This could have
1935        led to memory overwriting.
1936    
1937     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1938    
1939     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1940        operating environments where this matters.
1941    
1942     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1943        PCRE options from within the C++ wrapper.
1944    
1945     5. Named capturing subpatterns were not being correctly counted when a pattern
1946        was compiled. This caused two problems: (a) If there were more than 100
1947        such subpatterns, the calculation of the memory needed for the whole
1948        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1949        back references of the form \12, where the number was greater than 9, were
1950        not recognized as back references, even though there were sufficient
1951        previous subpatterns.
1952    
1953     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1954        versions of gcc, e.g. 2.95.4.
1955    
1956    
1957    Version 6.1 21-Jun-05
1958    ---------------------
1959    
1960     1. There was one reference to the variable "posix" in pcretest.c that was not
1961        surrounded by "#if !defined NOPOSIX".
1962    
1963     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1964        the cross-check on the old pcre_info() function, for the benefit of the
1965        cut-down version of PCRE that is currently imported into Exim.
1966    
1967     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1968        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1969        patterns that start (?i) but I don't think that matters. The use of (?i) is
1970        just an example; this all applies to the other options as well.
1971    
1972     4. Since libtool seems to echo the compile commands it is issuing, the output
1973        from "make" can be reduced a bit by putting "@" in front of each libtool
1974        compile command.
1975    
1976     5. Patch from the folks at Google for configure.in to be a bit more thorough
1977        in checking for a suitable C++ installation before trying to compile the
1978        C++ stuff. This should fix a reported problem when a compiler was present,
1979        but no suitable headers.
1980    
1981     6. The man pages all had just "PCRE" as their title. I have changed them to
1982        be the relevant file name. I have also arranged that these names are
1983        retained in the file doc/pcre.txt, which is a concatenation in text format
1984        of all the man pages except the little individual ones for each function.
1985    
1986     7. The NON-UNIX-USE file had not been updated for the different set of source
1987        files that come with release 6. I also added a few comments about the C++
1988        wrapper.
1989    
1990    
1991    Version 6.0 07-Jun-05
1992    ---------------------
1993    
1994     1. Some minor internal re-organization to help with my DFA experiments.
1995    
1996     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1997        didn't matter for the library itself when fully configured, but did matter
1998        when compiling without UCP support, or within Exim, where the ucp files are
1999        not imported.
2000    
2001     3. Refactoring of the library code to split up the various functions into
2002        different source modules. The addition of the new DFA matching code (see
2003        below) to a single monolithic source would have made it really too
2004        unwieldy, quite apart from causing all the code to be include in a
2005        statically linked application, when only some functions are used. This is
2006        relevant even without the DFA addition now that patterns can be compiled in
2007        one application and matched in another.
2008    
2009        The downside of splitting up is that there have to be some external
2010        functions and data tables that are used internally in different modules of
2011        the library but which are not part of the API. These have all had their
2012        names changed to start with "_pcre_" so that they are unlikely to clash
2013        with other external names.
2014    
2015     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2016        a different (DFA) algorithm. Although it is slower than the original
2017        function, it does have some advantages for certain types of matching
2018        problem.
2019    
2020     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2021        including restarting after a partial match.
2022    
2023     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2024        defined when compiling for Windows was sent to me. I have put it into the
2025        code, though I have no means of testing or verifying it.
2026    
2027     7. Added the pcre_refcount() auxiliary function.
2028    
2029     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2030        match before or at the first newline in the subject string. In pcretest,
2031        the /f option on a pattern can be used to set this.
2032    
2033     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2034        would behave wrongly. This has been present in PCRE since release 4.0.
2035    
2036    10. A number of changes to the pcregrep command:
2037    
2038        (a) Refactored how -x works; insert ^(...)$ instead of setting
2039            PCRE_ANCHORED and checking the length, in preparation for adding
2040            something similar for -w.
2041    
2042        (b) Added the -w (match as a word) option.
2043    
2044        (c) Refactored the way lines are read and buffered so as to have more
2045            than one at a time available.
2046    
2047        (d) Implemented a pcregrep test script.
2048    
2049        (e) Added the -M (multiline match) option. This allows patterns to match
2050            over several lines of the subject. The buffering ensures that at least
2051            8K, or the rest of the document (whichever is the shorter) is available
2052            for matching (and similarly the previous 8K for lookbehind assertions).
2053    
2054        (f) Changed the --help output so that it now says
2055    
2056              -w, --word-regex(p)
2057    
2058            instead of two lines, one with "regex" and the other with "regexp"
2059            because that confused at least one person since the short forms are the
2060            same. (This required a bit of code, as the output is generated
2061            automatically from a table. It wasn't just a text change.)
2062    
2063        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2064            option but starts with a hyphen. Could be a pattern or a path name
2065            starting with a hyphen, for instance.
2066    
2067        (h) "-" can be given as a file name to represent stdin.
2068    
2069        (i) When file names are being printed, "(standard input)" is used for
2070            the standard input, for compatibility with GNU grep. Previously
2071            "<stdin>" was used.
2072    
2073        (j) The option --label=xxx can be used to supply a name to be used for
2074            stdin when file names are being printed. There is no short form.
2075    
2076        (k) Re-factored the options decoding logic because we are going to add
2077            two more options that take data. Such options can now be given in four
2078            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2079    
2080        (l) Added the -A, -B, and -C options for requesting that lines of context
2081            around matches be printed.
2082    
2083        (m) Added the -L option to print the names of files that do not contain
2084            any matching lines, that is, the complement of -l.
2085    
2086        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2087            continue to scan other files.
2088    
2089        (o) The -s option was incorrectly implemented. For compatibility with other
2090            greps, it now suppresses the error message for a non-existent or non-
2091            accessible file (but not the return code). There is a new option called
2092            -q that suppresses the output of matching lines, which was what -s was
2093            previously doing.
2094    
2095        (p) Added --include and --exclude options to specify files for inclusion
2096            and exclusion when recursing.
2097    
2098    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2099        Hopefully, it now does.
2100    
2101    12. Missing cast in pcre_study().
2102    
2103    13. Added an "uninstall" target to the makefile.
2104    
2105    14. Replaced "extern" in the function prototypes in Makefile.in with
2106        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2107        world, but is set differently for Windows.
2108    
2109    15. Added a second compiling function called pcre_compile2(). The only
2110        difference is that it has an extra argument, which is a pointer to an
2111        integer error code. When there is a compile-time failure, this is set
2112        non-zero, in addition to the error test pointer being set to point to an
2113        error message. The new argument may be NULL if no error number is required
2114        (but then you may as well call pcre_compile(), which is now just a
2115        wrapper). This facility is provided because some applications need a
2116        numeric error indication, but it has also enabled me to tidy up the way
2117        compile-time errors are handled in the POSIX wrapper.
2118    
2119    16. Added VPATH=.libs to the makefile; this should help when building with one
2120        prefix path and installing with another. (Or so I'm told by someone who
2121        knows more about this stuff than I do.)
2122    
2123    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2124        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2125        match everything, including newlines. This is not POSIX-compatible, but
2126        somebody wanted the feature. From pcretest it can be activated by using
2127        both the P and the s flags.
2128    
2129    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2130    
2131    19. libpcre.pc was being incorrectly installed as executable.
2132    
2133    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2134        it now also looks for '\r' so that it will work unmodified on Windows.
2135    
2136    21. Added Google's contributed C++ wrapper to the distribution.
2137    
2138    22. Added some untidy missing memory free() calls in pcretest, to keep
2139        Electric Fence happy when testing.
2140    
2141    
2142    
2143    Version 5.0 13-Sep-04
2144    ---------------------
2145    
2146     1. Internal change: literal characters are no longer packed up into items
2147        containing multiple characters in a single byte-string. Each character
2148        is now matched using a separate opcode. However, there may be more than one
2149        byte in the character in UTF-8 mode.
2150    
2151     2. The pcre_callout_block structure has two new fields: pattern_position and
2152        next_item_length. These contain the offset in the pattern to the next match
2153        item, and its length, respectively.
2154    
2155     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2156        insertion of callouts before each pattern item. Added the /C option to
2157        pcretest to make use of this.
2158    
2159     4. On the advice of a Windows user, the lines
2160    
2161          #if defined(_WIN32) || defined(WIN32)
2162          _setmode( _fileno( stdout ), 0x8000 );
2163          #endif  /* defined(_WIN32) || defined(WIN32) */
2164    
2165        have been added to the source of pcretest. This apparently does useful
2166        magic in relation to line terminators.
2167    
2168     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2169        for the benefit of those environments where the "b" makes a difference.
2170    
2171     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2172        to know about it. I have put a hack into configure.in that adds in code
2173        to set GCC=yes if CC=icc. This seems to end up at a point in the
2174        generated configure script that is early enough to affect the setting of
2175        compiler options, which is what is needed, but I have no means of testing
2176        whether it really works. (The user who reported this had patched the
2177        generated configure script, which of course I cannot do.)
2178    
2179        LATER: After change 22 below (new libtool files), the configure script
2180        seems to know about icc (and also ecc). Therefore, I have commented out
2181        this hack in configure.in.
2182    
2183     7. Added support for pkg-config (2 patches were sent in).
2184    
2185     8. Negated POSIX character classes that used a combination of internal tables
2186        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2187        [[:^ascii]]. Typically, they would match almost any characters. The other
2188        POSIX classes were not broken in this way.
2189    
2190     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2191        to find the match, as PCRE was deluded into thinking that the match had to
2192        start at the start point or following a newline. The same bug applied to
2193        patterns with negative forward assertions or any backward assertions
2194        preceding ".*" at the start, unless the pattern required a fixed first
2195        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2196    
2197    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2198        starting at the last subject character, bytes beyond the end of the subject
2199        string were read.
2200    
2201    11. Renamed the variable "class" as "classbits" to make life easier for C++
2202        users. (Previously there was a macro definition, but it apparently wasn't
2203        enough.)
2204    
2205    12. Added the new field "tables" to the extra data so that tables can be passed
2206        in at exec time, or the internal tables can be re-selected. This allows
2207        a compiled regex to be saved and re-used at a later time by a different
2208        program that might have everything at different addresses.
2209    
2210    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2211        -R library as well as a -L library.
2212    
2213    14. The debugging options of pcretest (-d on the command line or D on a
2214        pattern) showed incorrect output for anything following an extended class
2215        that contained multibyte characters and which was followed by a quantifier.
2216    
2217    15. Added optional support for general category Unicode character properties
2218        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2219        support. It adds about 90K to the size of the library. The meanings of the
2220        inbuilt class escapes such as \d and \s have NOT been changed.
2221    
2222    16. Updated pcredemo.c to include calls to free() to release the memory for the
2223        compiled pattern.
2224    
2225    17. The generated file chartables.c was being created in the source directory
2226        instead of in the building directory. This caused the build to fail if the
2227        source directory was different from the building directory, and was
2228        read-only.
2229    
2230    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2231        file. No doubt somebody will tell me if they don't make sense... Also added
2232        Dan Mooney's comments about building on OpenVMS.
2233    
2234    19. Added support for partial matching via the PCRE_PARTIAL option for
2235        pcre_exec() and the \P data escape in pcretest.
2236    
2237    20. Extended pcretest with 3 new pattern features:
2238    
2239        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2240              write the compiled pattern to the file whose name is "rest-of-line".
2241              This is a straight binary dump of the data, with the saved pointer to
2242              the character tables forced to be NULL. The study data, if any, is
2243              written too. After writing, pcretest reads a new pattern.
2244    
2245        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2246              compiled pattern from the given file. There must not be any
2247              occurrences of "<" in the file name (pretty unlikely); if there are,
2248              pcretest will instead treat the initial "<" as a pattern delimiter.
2249              After reading in the pattern, pcretest goes on to read data lines as
2250              usual.
2251    
2252        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2253              and 16-bit fields in a compiled pattern, to simulate a pattern that
2254              was compiled on a host of opposite endianness.
2255    
2256    21. The pcre-exec() function can now cope with patterns that were compiled on
2257        hosts of opposite endianness, with this restriction:
2258    
2259          As for any compiled expression that is saved and used later, the tables
2260          pointer field cannot be preserved; the extra_data field in the arguments
2261          to pcre_exec() should be used to pass in a tables address if a value
2262          other than the default internal tables were used at compile time.
2263    
2264    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2265        now diagnosed as an error. Previously, most of the time, a negative number
2266        would have been treated as zero, but if in addition "ovector" was passed as
2267        NULL, a crash could occur.
2268    
2269    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2270        new versions from the libtool 1.5 distribution (the last one is a copy of
2271        a file called libtool.m4). This seems to have fixed the need to patch
2272        "configure" to support Darwin 1.3 (which I used to do). However, I still
2273        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2274        workstation).
2275    
2276    24. Changed the PCRE licence to be the more standard "BSD" licence.
2277    
2278    
2279    Version 4.5 01-Dec-03
2280    ---------------------
2281    
2282     1. There has been some re-arrangement of the code for the match() function so
2283        that it can be compiled in a version that does not call itself recursively.
2284        Instead, it keeps those local variables that need separate instances for
2285        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2286        needs to "recurse". Keeping track of where control must go is done by means
2287        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2288        hide most of the details from the main code, and operates only if
2289        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2290        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2291        operating.
2292    
2293        To make it easier for callers to provide specially tailored get/free
2294        functions for this usage, two new functions, pcre_stack_malloc, and
2295        pcre_stack_free, are used. They are always called in strict stacking order,
2296        and the size of block requested is always the same.
2297    
2298        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2299        PCRE has been compiled to use the stack or the heap for recursion. The
2300        -C option of pcretest uses this to show which version is compiled.
2301    
2302        A new data escape \S, is added to pcretest; it causes the amounts of store
2303        obtained and freed by both kinds of malloc/free at match time to be added
2304        to the output.
2305    
2306     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2307        what's available on my current Linux desktop machine.
2308    
2309     3. When matching a UTF-8 string, the test for a valid string at the start has
2310        been extended. If start_offset is not zero, PCRE now checks that it points
2311        to a byte that is the start of a UTF-8 character. If not, it returns
2312        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2313        this is necessary because there may be backward assertions in the pattern.
2314        When matching the same subject several times, it may save resources to use
2315        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2316    
2317     4. The code for checking the validity of UTF-8 strings has been tightened so
2318        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2319        containing "overlong sequences".
2320    
2321     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2322        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2323        should have been "&", but it just so happened that all the cases this let
2324        through by mistake were picked up later in the function.
2325    
2326     6. I had used a variable called "isblank" - this is a C99 function, causing
2327        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2328    
2329     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2330        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2331        so the version is shown; (c) stop "make test" echoing "./RunTest".
2332    
2333     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2334    
2335     9. The prototype for memmove() for systems that don't have it was using
2336        size_t, but the inclusion of the header that defines size_t was later. I've
2337        moved the #includes for the C headers earlier to avoid this.
2338    
2339    10. Added some adjustments to the code to make it easier to compiler on certain
2340        special systems:
2341    
2342          (a) Some "const" qualifiers were missing.
2343          (b) Added the macro EXPORT before all exported functions; by default this
2344              is defined to be empty.
2345          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2346              that it reads its output file name as an argument instead of writing
2347              to the standard output and assuming this can be redirected.
2348    
2349    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2350        class containing characters with values greater than 255, PCRE compilation
2351        went into a loop.
2352    
2353    12. A recursive reference to a subpattern that was within another subpattern
2354        that had a minimum quantifier of zero caused PCRE to crash. For example,
2355        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2356        recursion. If the recursively-called subpattern itself had a zero repeat,
2357        that was OK.
2358    
2359    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2360        buffer into which it was copied (for escape processing) was still set at
2361        1024, so long lines caused crashes.
2362    
2363    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2364        "internal error: code overflow...". This applied to any character class
2365        that was followed by a possessive quantifier.
2366    
2367    15. Modified the Makefile to add libpcre.la as a prerequisite for
2368        libpcreposix.la because I was told this is needed for a parallel build to
2369        work.
2370    
2371    16. If a pattern that contained .* following optional items at the start was
2372        studied, the wrong optimizing data was generated, leading to matching
2373        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2374        matching string must start with a or b or c. The correct conclusion for
2375        this pattern is that a match can start with any character.
2376    
2377    
2378  Version 4.4 13-Aug-03  Version 4.4 13-Aug-03
2379  ---------------------  ---------------------
2380    

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