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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    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
81        most of the time, it *can* run out if it is given a pattern that contains a
82        runaway infinite recursion. I updated the discussion in the pcrestack man
83        page.
84    
85    13. Now that we have gone to the x.xx style of version numbers, the minor
86        version may start with zero. Using 08 or 09 is a bad idea because users
87        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
88        interpreted as invalid octal numbers. I've updated the previous comment in
89        configure.ac, and also added a check that gives an error if 08 or 09 are
90        used.
91    
92    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
93        causing partial matching to fail where the end of the subject matched \W.
94    
95    
96    
97    Version 8.00 19-Oct-09
98    ----------------------
99    
100    1.  The table for translating pcre_compile() error codes into POSIX error codes
101        was out-of-date, and there was no check on the pcre_compile() error code
102        being within the table. This could lead to an OK return being given in
103        error.
104    
105    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
106        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
107        in a Windows environment.
108    
109    3.  The pcregrep --count option prints the count for each file even when it is
110        zero, as does GNU grep. However, pcregrep was also printing all files when
111        --files-with-matches was added. Now, when both options are given, it prints
112        counts only for those files that have at least one match. (GNU grep just
113        prints the file name in this circumstance, but including the count seems
114        more useful - otherwise, why use --count?) Also ensured that the
115        combination -clh just lists non-zero counts, with no names.
116    
117    4.  The long form of the pcregrep -F option was incorrectly implemented as
118        --fixed_strings instead of --fixed-strings. This is an incompatible change,
119        but it seems right to fix it, and I didn't think it was worth preserving
120        the old behaviour.
121    
122    5.  The command line items --regex=pattern and --regexp=pattern were not
123        recognized by pcregrep, which required --regex pattern or --regexp pattern
124        (with a space rather than an '='). The man page documented the '=' forms,
125        which are compatible with GNU grep; these now work.
126    
127    6.  No libpcreposix.pc file was created for pkg-config; there was just
128        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
129    
130    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
131        when UCP support is not needed, by modifying the Python script that
132        generates it from Unicode data files. This should not matter if the module
133        is correctly used as a library, but I received one complaint about 50K of
134        unwanted data. My guess is that the person linked everything into his
135        program rather than using a library. Anyway, it does no harm.
136    
137    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
138        was a minimum greater than 1 for a wide character in a possessive
139        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
140        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
141        character. Chaos in the form of incorrect output or a compiling loop could
142        result.
143    
144    9.  The restrictions on what a pattern can contain when partial matching is
145        requested for pcre_exec() have been removed. All patterns can now be
146        partially matched by this function. In addition, if there are at least two
147        slots in the offset vector, the offset of the earliest inspected character
148        for the match and the offset of the end of the subject are set in them when
149        PCRE_ERROR_PARTIAL is returned.
150    
151    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
152        synonymous with PCRE_PARTIAL, for backwards compatibility, and
153        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
154        and may be more useful for multi-segment matching.
155    
156    11. Partial matching with pcre_exec() is now more intuitive. A partial match
157        used to be given if ever the end of the subject was reached; now it is
158        given only if matching could not proceed because another character was
159        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
160        string "Z", which now yields "no match" instead of "partial match". In the
161        case of pcre_dfa_exec(), "no match" is given if every matching path for the
162        final character ended with (*FAIL).
163    
164    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
165        if the pattern had a "must contain" character that was already found in the
166        earlier partial match, unless partial matching was again requested. For
167        example, with the pattern /dog.(body)?/, the "must contain" character is
168        "g". If the first part-match was for the string "dog", restarting with
169        "sbody" failed. This bug has been fixed.
170    
171    13. The string returned by pcre_dfa_exec() after a partial match has been
172        changed so that it starts at the first inspected character rather than the
173        first character of the match. This makes a difference only if the pattern
174        starts with a lookbehind assertion or \b or \B (\K is not supported by
175        pcre_dfa_exec()). It's an incompatible change, but it makes the two
176        matching functions compatible, and I think it's the right thing to do.
177    
178    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
179        so that the demonstration program is easily available in environments where
180        PCRE has not been installed from source.
181    
182    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
183        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
184        library.
185    
186    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
187        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
188        is not the first non-POSIX option to be added. Clearly some people find
189        these options useful.
190    
191    17. If a caller to the POSIX matching function regexec() passes a non-zero
192        value for nmatch with a NULL value for pmatch, the value of
193        nmatch is forced to zero.
194    
195    18. RunGrepTest did not have a test for the availability of the -u option of
196        the diff command, as RunTest does. It now checks in the same way as
197        RunTest, and also checks for the -b option.
198    
199    19. If an odd number of negated classes containing just a single character
200        interposed, within parentheses, between a forward reference to a named
201        subpattern and the definition of the subpattern, compilation crashed with
202        an internal error, complaining that it could not find the referenced
203        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
204        [The bug was that it was starting one character too far in when skipping
205        over the character class, thus treating the ] as data rather than
206        terminating the class. This meant it could skip too much.]
207    
208    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
209        /g option in pcretest when the pattern contains \K, which makes it possible
210        to have an empty string match not at the start, even when the pattern is
211        anchored. Updated pcretest and pcredemo to use this option.
212    
213    21. If the maximum number of capturing subpatterns in a recursion was greater
214        than the maximum at the outer level, the higher number was returned, but
215        with unset values at the outer level. The correct (outer level) value is
216        now given.
217    
218    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
219        PCRE did not set those parentheses (unlike Perl). I have now found a way to
220        make it do so. The string so far is captured, making this feature
221        compatible with Perl.
222    
223    23. The tests have been re-organized, adding tests 11 and 12, to make it
224        possible to check the Perl 5.10 features against Perl 5.10.
225    
226    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
227        pattern matches a fixed length string. PCRE did not allow this; now it
228        does. Neither allows recursion.
229    
230    25. I finally figured out how to implement a request to provide the minimum
231        length of subject string that was needed in order to match a given pattern.
232        (It was back references and recursion that I had previously got hung up
233        on.) This code has now been added to pcre_study(); it finds a lower bound
234        to the length of subject needed. It is not necessarily the greatest lower
235        bound, but using it to avoid searching strings that are too short does give
236        some useful speed-ups. The value is available to calling programs via
237        pcre_fullinfo().
238    
239    26. While implementing 25, I discovered to my embarrassment that pcretest had
240        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
241        study optimizations had never been tested with that matching function.
242        Oops. What is worse, even when it was passed study data, there was a bug in
243        pcre_dfa_exec() that meant it never actually used it. Double oops. There
244        were also very few tests of studied patterns with pcre_dfa_exec().
245    
246    27. If (?| is used to create subpatterns with duplicate numbers, they are now
247        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
248        on the other side of the coin, they are no longer allowed to have different
249        names, because these cannot be distinguished in PCRE, and this has caused
250        confusion. (This is a difference from Perl.)
251    
252    28. When duplicate subpattern names are present (necessarily with different
253        numbers, as required by 27 above), and a test is made by name in a
254        conditional pattern, either for a subpattern having been matched, or for
255        recursion in such a pattern, all the associated numbered subpatterns are
256        tested, and the overall condition is true if the condition is true for any
257        one of them. This is the way Perl works, and is also more like the way
258        testing by number works.
259    
260    
261    Version 7.9 11-Apr-09
262    ---------------------
263    
264    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
265        (pcretest), all targets were linked against these libraries. This included
266        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
267        libraries. This caused unwanted dependencies to be created. This problem
268        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
269        pcretest is linked with readline.
270    
271    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
272        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
273        moved outside it again, because FALSE and TRUE are already defined in AIX,
274        but BOOL is not.
275    
276    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
277        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
278    
279    4.  The pcregrep documentation said spaces were inserted as well as colons (or
280        hyphens) following file names and line numbers when outputting matching
281        lines. This is not true; no spaces are inserted. I have also clarified the
282        wording for the --colour (or --color) option.
283    
284    5.  In pcregrep, when --colour was used with -o, the list of matching strings
285        was not coloured; this is different to GNU grep, so I have changed it to be
286        the same.
287    
288    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
289        each matching line was coloured. Now it goes on to look for further matches
290        of any of the test patterns, which is the same behaviour as GNU grep.
291    
292    7.  A pattern that could match an empty string could cause pcregrep to loop; it
293        doesn't make sense to accept an empty string match in pcregrep, so I have
294        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
295        seems to be how GNU grep behaves.
296    
297    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
298        start or after a newline", because the conditional assertion was not being
299        correctly handled. The rule now is that both the assertion and what follows
300        in the first alternative must satisfy the test.
301    
302    9.  If auto-callout was enabled in a pattern with a conditional group whose
303        condition was an assertion, PCRE could crash during matching, both with
304        pcre_exec() and pcre_dfa_exec().
305    
306    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
307        used for matching.
308    
309    11. Unicode property support in character classes was not working for
310        characters (bytes) greater than 127 when not in UTF-8 mode.
311    
312    12. Added the -M command line option to pcretest.
313    
314    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
315    
316    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
317    
318    16. Added comments and documentation about mis-use of no_arg in the C++
319        wrapper.
320    
321    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
322        from Martin Jerabek that uses macro names for all relevant character and
323        string constants.
324    
325    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
326        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
327        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
328        these, but not everybody uses configure.
329    
330    19. A conditional group that had only one branch was not being correctly
331        recognized as an item that could match an empty string. This meant that an
332        enclosing group might also not be so recognized, causing infinite looping
333        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
334        with the subject "ab", where knowledge that the repeated group can match
335        nothing is needed in order to break the loop.
336    
337    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
338        exec(), but without supplying a callout function, matching went wrong.
339    
340    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
341        leak if the size of the offset vector was greater than 30. When the vector
342        is smaller, the saved offsets during recursion go onto a local stack
343        vector, but for larger vectors malloc() is used. It was failing to free
344        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
345        error, in fact).
346    
347    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
348        heapframe that is used only when UTF-8 support is enabled. This caused no
349        problem, but was untidy.
350    
351    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
352        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
353        included within another project.
354    
355    24. Steven Van Ingelgem's patches to add more options to the CMake support,
356        slightly modified by me:
357    
358          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
359              not building pcregrep.
360    
361          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
362              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
363    
364    25. Forward references, both numeric and by name, in patterns that made use of
365        duplicate group numbers, could behave incorrectly or give incorrect errors,
366        because when scanning forward to find the reference group, PCRE was not
367        taking into account the duplicate group numbers. A pattern such as
368        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
369    
370    26. Changed a few more instances of "const unsigned char *" to USPTR, making
371        the feature of a custom pointer more persuasive (as requested by a user).
372    
373    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
374        pcretest.c, inside #ifndefs, because it seems they are sometimes already
375        pre-defined.
376    
377    28. Added support for (*UTF8) at the start of a pattern.
378    
379    29. Arrange for flags added by the "release type" setting in CMake to be shown
380        in the configuration summary.
381    
382    
383    Version 7.8 05-Sep-08
384    ---------------------
385    
386    1.  Replaced UCP searching code with optimized version as implemented for Ad
387        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
388        stage table and inline lookup instead of a function, giving speed ups of 2
389        to 5 times on some simple patterns that I tested. Permission was given to
390        distribute the MultiStage2.py script that generates the tables (it's not in
391        the tarball, but is in the Subversion repository).
392    
393    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
394        scripts.
395    
396    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
397        a group with a zero qualifier. The result of the study could be incorrect,
398        or the function might crash, depending on the pattern.
399    
400    4.  Caseless matching was not working for non-ASCII characters in back
401        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
402        It now works when Unicode Property Support is available.
403    
404    5.  In pcretest, an escape such as \x{de} in the data was always generating
405        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
406        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
407        truncation.
408    
409    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
410    
411    7.  Added two (int) casts to pcregrep when printing the difference of two
412        pointers, in case they are 64-bit values.
413    
414    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
415        test 2 if it fails.
416    
417    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
418        and a #define of that name to empty if it is not externally set. This is to
419        allow users of MSVC to set it if necessary.
420    
421    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
422        the convenience functions in the pcre_get.c source file.
423    
424    11. An option change at the start of a pattern that had top-level alternatives
425        could cause overwriting and/or a crash. This command provoked a crash in
426        some environments:
427    
428          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
429    
430        This potential security problem was recorded as CVE-2008-2371.
431    
432    12. For a pattern where the match had to start at the beginning or immediately
433        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
434        pcre_dfa_exec() could read past the end of the passed subject if there was
435        no match. To help with detecting such bugs (e.g. with valgrind), I modified
436        pcretest so that it places the subject at the end of its malloc-ed buffer.
437    
438    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
439        exec() might read past the end of the data buffer in UTF-8 mode.
440    
441    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
442        the data contained the byte 0x85 as part of a UTF-8 character within its
443        first line. This applied both to normal and DFA matching.
444    
445    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
446        /^[^d]*?$/8 failed to match "abc".
447    
448    16. Added a missing copyright notice to pcrecpp_internal.h.
449    
450    17. Make it more clear in the documentation that values returned from
451        pcre_exec() in ovector are byte offsets, not character counts.
452    
453    18. Tidied a few places to stop certain compilers from issuing warnings.
454    
455    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
456        supplied by Stefan Weber. I made a further small update for 7.8 because
457        there is a change of source arrangements: the pcre_searchfuncs.c module is
458        replaced by pcre_ucd.c.
459    
460    
461    Version 7.7 07-May-08
462    ---------------------
463    
464    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
465        a string to a long long, pretend we don't even have a long long." This is
466        done by checking for the strtoq, strtoll, and _strtoi64 functions.
467    
468    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
469        pre-7.6 versions, which defined a global no_arg variable instead of putting
470        it in the RE class. (See also #8 below.)
471    
472    3.  Remove a line of dead code, identified by coverity and reported by Nuno
473        Lopes.
474    
475    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
476    
477        (1) The include/exclude patterns were being applied to the whole pathnames
478            of files, instead of just to the final components.
479    
480        (2) If there was more than one level of directory, the subdirectories were
481            skipped unless they satisfied the include/exclude conditions. This is
482            inconsistent with GNU grep (and could even be seen as contrary to the
483            pcregrep specification - which I improved to make it absolutely clear).
484            The action now is always to scan all levels of directory, and just
485            apply the include/exclude patterns to regular files.
486    
487    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
488        --exclude_dir in the tests to avoid scanning .svn directories.
489    
490    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
491        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
492        doesn't support NULs in patterns.
493    
494    7.  Added some missing "const"s to declarations of static tables in
495        pcre_compile.c and pcre_dfa_exec.c.
496    
497    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
498        caused by fix #2  above. (Subsequently also a second patch to fix the
499        first patch. And a third patch - this was a messy problem.)
500    
501    9.  Applied Craig's patch to remove the use of push_back().
502    
503    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
504        matching function regexec().
505    
506    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
507        which, however, unlike Perl's \g{...}, are subroutine calls, not back
508        references. PCRE supports relative numbers with this syntax (I don't think
509        Oniguruma does).
510    
511    12. Previously, a group with a zero repeat such as (...){0} was completely
512        omitted from the compiled regex. However, this means that if the group
513        was called as a subroutine from elsewhere in the pattern, things went wrong
514        (an internal error was given). Such groups are now left in the compiled
515        pattern, with a new opcode that causes them to be skipped at execution
516        time.
517    
518    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
519        to the way PCRE behaves:
520    
521        (a) A lone ] character is dis-allowed (Perl treats it as data).
522    
523        (b) A back reference to an unmatched subpattern matches an empty string
524            (Perl fails the current match path).
525    
526        (c) A data ] in a character class must be notated as \] because if the
527            first data character in a class is ], it defines an empty class. (In
528            Perl it is not possible to have an empty class.) The empty class []
529            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
530            The negative empty class [^] matches any one character, independently
531            of the DOTALL setting.
532    
533    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
534        non-existent subpattern following a character class starting with ']' and
535        containing () gave an internal compiling error instead of "reference to
536        non-existent subpattern". Fortunately, when the pattern did exist, the
537        compiled code was correct. (When scanning forwards to check for the
538        existencd of the subpattern, it was treating the data ']' as terminating
539        the class, so got the count wrong. When actually compiling, the reference
540        was subsequently set up correctly.)
541    
542    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
543        it was being rejected as not supported by pcre_dfa_exec(), even though
544        other assertions are supported. I have made pcre_dfa_exec() support
545        (*FAIL).
546    
547    16. The implementation of 13c above involved the invention of a new opcode,
548        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
549        cannot be changed at match time, I realized I could make a small
550        improvement to matching performance by compiling OP_ALLANY instead of
551        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
552        on the OP_ANY path.
553    
554    17. Compiling pcretest on Windows with readline support failed without the
555        following two fixes: (1) Make the unistd.h include conditional on
556        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
557    
558    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
559        ncurses library to be included for pcretest when ReadLine support is
560        requested, but also to allow for it to be overridden. This patch came from
561        Daniel Bergström.
562    
563    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
564        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
565        any errors with the current Unicode tables. Thanks to Peter Kankowski for
566        spotting this.
567    
568    
569    Version 7.6 28-Jan-08
570    ---------------------
571    
572    1.  A character class containing a very large number of characters with
573        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
574        overflow.
575    
576    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
577        HAVE_LONG_LONG is not defined.
578    
579    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
580        bring them up to date and include new features. This patch includes:
581    
582        - Fixed PH's badly added libz and libbz2 support.
583        - Fixed a problem with static linking.
584        - Added pcredemo. [But later removed - see 7 below.]
585        - Fixed dftables problem and added an option.
586        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
587            HAVE_LONG_LONG.
588        - Added readline support for pcretest.
589        - Added an listing of the option settings after cmake has run.
590    
591    4.  A user submitted a patch to Makefile that makes it easy to create
592        "pcre.dll" under mingw when using Configure/Make. I added stuff to
593        Makefile.am that cause it to include this special target, without
594        affecting anything else. Note that the same mingw target plus all
595        the other distribution libraries and programs are now supported
596        when configuring with CMake (see 6 below) instead of with
597        Configure/Make.
598    
599    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
600        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
601        exported in the Windows port". It has not yet been confirmed that the patch
602        solves the problem, but it does no harm.
603    
604    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
605        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
606        with CMake, and also correct the comment about stack recursion.
607    
608    7.  Remove the automatic building of pcredemo from the ./configure system and
609        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
610        of a program that users should build themselves after PCRE is installed, so
611        building it automatically is not really right. What is more, it gave
612        trouble in some build environments.
613    
614    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
615    
616    
617    Version 7.5 10-Jan-08
618    ---------------------
619    
620    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
621        values in parens when parsing an RE using the C++ wrapper."
622    
623    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
624        Characters greater than 255 were excluded from the class instead of being
625        included.
626    
627    3.  The same bug as (2) above applied to negated POSIX classes such as
628        [:^space:].
629    
630    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
631        defined or documented. It seems to have been a typo for PCRE_STATIC, so
632        I have changed it.
633    
634    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
635        first named subpattern) and a construct such as (?&a) would reference the
636        first named subpattern whose name started with "a" (in other words, the
637        length check was missing). Both these problems are fixed. "Subpattern name
638        expected" is now given for (?&) (a zero-length name), and this patch also
639        makes it give the same error for \k'' (previously it complained that that
640        was a reference to a non-existent subpattern).
641    
642    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
643        this is right because (?- can be followed by option settings as well as by
644        digits. I have, however, made the messages clearer.
645    
646    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
647        than the number used in the conditional) now cause a compile-time error.
648        This is actually not compatible with Perl, which accepts such patterns, but
649        treats the conditional as always being FALSE (as PCRE used to), but it
650        seems to me that giving a diagnostic is better.
651    
652    8.  Change "alphameric" to the more common word "alphanumeric" in comments
653        and messages.
654    
655    9.  Fix two occurrences of "backslash" in comments that should have been
656        "backspace".
657    
658    10. Remove two redundant lines of code that can never be obeyed (their function
659        was moved elsewhere).
660    
661    11. The program that makes PCRE's Unicode character property table had a bug
662        which caused it to generate incorrect table entries for sequences of
663        characters that have the same character type, but are in different scripts.
664        It amalgamated them into a single range, with the script of the first of
665        them. In other words, some characters were in the wrong script. There were
666        thirteen such cases, affecting characters in the following ranges:
667    
668          U+002b0 - U+002c1
669          U+0060c - U+0060d
670          U+0061e - U+00612
671          U+0064b - U+0065e
672          U+0074d - U+0076d
673          U+01800 - U+01805
674          U+01d00 - U+01d77
675          U+01d9b - U+01dbf
676          U+0200b - U+0200f
677          U+030fc - U+030fe
678          U+03260 - U+0327f
679          U+0fb46 - U+0fbb1
680          U+10450 - U+1049d
681    
682    12. The -o option (show only the matching part of a line) for pcregrep was not
683        compatible with GNU grep in that, if there was more than one match in a
684        line, it showed only the first of them. It now behaves in the same way as
685        GNU grep.
686    
687    13. If the -o and -v options were combined for pcregrep, it printed a blank
688        line for every non-matching line. GNU grep prints nothing, and pcregrep now
689        does the same. The return code can be used to tell if there were any
690        non-matching lines.
691    
692    14. Added --file-offsets and --line-offsets to pcregrep.
693    
694    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
695        infinitely looping recursion. The bug was that positive lookaheads were not
696        being skipped when checking for a possible empty match (negative lookaheads
697        and both kinds of lookbehind were skipped).
698    
699    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
700        inclusion of <windows.h> to before rather than after the definition of
701        INVALID_FILE_ATTRIBUTES (patch from David Byron).
702    
703    17. Specifying a possessive quantifier with a specific limit for a Unicode
704        character property caused pcre_compile() to compile bad code, which led at
705        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
706        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
707        caused the error; without that there was no problem.
708    
709    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
710    
711    19. Added --enable-pcretest-libreadline.
712    
713    20. In pcrecpp.cc, the variable 'count' was incremented twice in
714        RE::GlobalReplace(). As a result, the number of replacements returned was
715        double what it should be. I removed one of the increments, but Craig sent a
716        later patch that removed the other one (the right fix) and added unit tests
717        that check the return values (which was not done before).
718    
719    21. Several CMake things:
720    
721        (1) Arranged that, when cmake is used on Unix, the libraries end up with
722            the names libpcre and libpcreposix, not just pcre and pcreposix.
723    
724        (2) The above change means that pcretest and pcregrep are now correctly
725            linked with the newly-built libraries, not previously installed ones.
726    
727        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
728    
729    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
730        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
731        UTF-8 newline character). The key issue is that the pattern starts .*;
732        this means that the match must be either at the beginning, or after a
733        newline. The bug was in the code for advancing after a failed match and
734        checking that the new position followed a newline. It was not taking
735        account of UTF-8 characters correctly.
736    
737    23. PCRE was behaving differently from Perl in the way it recognized POSIX
738        character classes. PCRE was not treating the sequence [:...:] as a
739        character class unless the ... were all letters. Perl, however, seems to
740        allow any characters between [: and :], though of course it rejects as
741        unknown any "names" that contain non-letters, because all the known class
742        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
743        for example, whereas PCRE did not - it did not recognize a POSIX character
744        class. This seemed a bit dangerous, so the code has been changed to be
745        closer to Perl. The behaviour is not identical to Perl, because PCRE will
746        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
747        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
748        Perl does, and where it didn't before.
749    
750    24. Rewrite so as to remove the single use of %n from pcregrep because in some
751        Windows environments %n is disabled by default.
752    
753    
754    Version 7.4 21-Sep-07
755    ---------------------
756    
757    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
758        means that a class such as [\s] counted as "explicit reference to CR or
759        LF". That isn't really right - the whole point of the change was to try to
760        help when there was an actual mention of one of the two characters. So now
761        the change happens only if \r or \n (or a literal CR or LF) character is
762        encountered.
763    
764    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
765        of both had grown to the point where there were only 3 bits left.
766        Fortunately, there was spare space in the data structure, and so I have
767        moved the internal flags into a new 16-bit field to free up more option
768        bits.
769    
770    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
771        but did not set the internal JCHANGED flag - either of these is enough to
772        control the way the "get" function works - but the PCRE_INFO_JCHANGED
773        facility is supposed to tell if (?J) was ever used, so now (?J) at the
774        start sets both bits.
775    
776    4.  Added options (at build time, compile time, exec time) to change \R from
777        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
778    
779    5.  doc/pcresyntax.html was missing from the distribution.
780    
781    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
782        compatibility, even though it is no longer used.
783    
784    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
785        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
786        windows.h file is present (where different names are used). [This was
787        reversed later after testing - see 16 below.]
788    
789    8.  Changed all #include <config.h> to #include "config.h". There were also
790        some further <pcre.h> cases that I changed to "pcre.h".
791    
792    9.  When pcregrep was used with the --colour option, it missed the line ending
793        sequence off the lines that it output.
794    
795    10. It was pointed out to me that arrays of string pointers cause lots of
796        relocations when a shared library is dynamically loaded. A technique of
797        using a single long string with a table of offsets can drastically reduce
798        these. I have refactored PCRE in four places to do this. The result is
799        dramatic:
800    
801          Originally:                          290
802          After changing UCP table:            187
803          After changing error message table:   43
804          After changing table of "verbs"       36
805          After changing table of Posix names   22
806    
807        Thanks to the folks working on Gregex for glib for this insight.
808    
809    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
810        unicode-properties was also set.
811    
812    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
813    
814    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
815        checked only for CRLF.
816    
817    14. Added casts to pcretest.c to avoid compiler warnings.
818    
819    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
820    
821    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
822        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
823        entirely. This removes changes made in 7 above.
824    
825    17. The CMake files have been updated, and there is now more information about
826        building with CMake in the NON-UNIX-USE document.
827    
828    
829    Version 7.3 28-Aug-07
830    ---------------------
831    
832     1. In the rejigging of the build system that eventually resulted in 7.1, the
833        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
834        brackets there is not right, since it causes compilers to look for an
835        installed pcre.h, not the version that is in the source that is being
836        compiled (which of course may be different). I have changed it back to:
837    
838          #include "pcre.h"
839    
840        I have a vague recollection that the change was concerned with compiling in
841        different directories, but in the new build system, that is taken care of
842        by the VPATH setting the Makefile.
843    
844     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
845        when the subject happened to end in the byte 0x85 (e.g. if the last
846        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
847        characters but of course it shouldn't be taken as a newline when it is part
848        of another character. The bug was that, for an unlimited repeat of . in
849        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
850        characters when looking for a newline.
851    
852     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
853    
854     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
855        in debug output.
856    
857     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
858        long printing in the pcrecpp unittest when running under MinGW.
859    
860     6. ESC_K was left out of the EBCDIC table.
861    
862     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
863        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
864        limit also applies to "virtual nesting" when a pattern is recursive, and in
865        this case 1000 isn't so big. I have been able to remove this limit at the
866        expense of backing off one optimization in certain circumstances. Normally,
867        when pcre_exec() would call its internal match() function recursively and
868        immediately return the result unconditionally, it uses a "tail recursion"
869        feature to save stack. However, when a subpattern that can match an empty
870        string has an unlimited repetition quantifier, it no longer makes this
871        optimization. That gives it a stack frame in which to save the data for
872        checking that an empty string has been matched. Previously this was taken
873        from the 1000-entry workspace that had been reserved. So now there is no
874        explicit limit, but more stack is used.
875    
876     8. Applied Daniel's patches to solve problems with the import/export magic
877        syntax that is required for Windows, and which was going wrong for the
878        pcreposix and pcrecpp parts of the library. These were overlooked when this
879        problem was solved for the main library.
880    
881     9. There were some crude static tests to avoid integer overflow when computing
882        the size of patterns that contain repeated groups with explicit upper
883        limits. As the maximum quantifier is 65535, the maximum group length was
884        set at 30,000 so that the product of these two numbers did not overflow a
885        32-bit integer. However, it turns out that people want to use groups that
886        are longer than 30,000 bytes (though not repeat them that many times).
887        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
888        made it possible to implement the integer overflow checks in a much more
889        dynamic way, which I have now done. The artificial limitation on group
890        length has been removed - we now have only the limit on the total length of
891        the compiled pattern, which depends on the LINK_SIZE setting.
892    
893    10. Fixed a bug in the documentation for get/copy named substring when
894        duplicate names are permitted. If none of the named substrings are set, the
895        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
896        empty string.
897    
898    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
899        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
900        because the ] is interpreted as the first data character and the
901        terminating ] is not found. PCRE has been made compatible with Perl in this
902        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
903        cause memory overwriting.
904    
905    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
906        string has been matched (to stop an infinite loop). It was not recognizing
907        a conditional subpattern that could match an empty string if that
908        subpattern was within another subpattern. For example, it looped when
909        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
910        condition was not nested. This bug has been fixed.
911    
912    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
913        past the start of the subject in the presence of bytes with the top bit
914        set, for example "\x8aBCD".
915    
916    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
917        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
918    
919    14. Optimized (?!) to (*FAIL).
920    
921    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
922        This restricts code points to be within the range 0 to 0x10FFFF, excluding
923        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
924        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
925        does: it's just the validity check that is more restrictive.
926    
927    16. Inserted checks for integer overflows during escape sequence (backslash)
928        processing, and also fixed erroneous offset values for syntax errors during
929        backslash processing.
930    
931    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
932        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
933    
934    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
935        caused an overrun.
936    
937    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
938        something other than just ASCII characters) inside a group that had an
939        unlimited repeat caused a loop at compile time (while checking to see
940        whether the group could match an empty string).
941    
942    20. Debugging a pattern containing \p or \P could cause a crash. For example,
943        [\P{Any}] did so. (Error in the code for printing property names.)
944    
945    21. An orphan \E inside a character class could cause a crash.
946    
947    22. A repeated capturing bracket such as (A)? could cause a wild memory
948        reference during compilation.
949    
950    23. There are several functions in pcre_compile() that scan along a compiled
951        expression for various reasons (e.g. to see if it's fixed length for look
952        behind). There were bugs in these functions when a repeated \p or \P was
953        present in the pattern. These operators have additional parameters compared
954        with \d, etc, and these were not being taken into account when moving along
955        the compiled data. Specifically:
956    
957        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
958            length.
959    
960        (b) An item such as \pL+ within a repeated group could cause crashes or
961            loops.
962    
963        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
964            "reference to non-existent subpattern" error.
965    
966        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
967    
968    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
969        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
970    
971    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
972    
973    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
974        character were causing crashes (broken optimization).
975    
976    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
977        \p or \P) caused a compile-time loop.
978    
979    28. More problems have arisen in unanchored patterns when CRLF is a valid line
980        break. For example, the unstudied pattern [\r\n]A does not match the string
981        "\r\nA" because change 7.0/46 below moves the current point on by two
982        characters after failing to match at the start. However, the pattern \nA
983        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
984        the same is true. There doesn't seem any very clean way out of this, but
985        what I have chosen to do makes the common cases work: PCRE now takes note
986        of whether there can be an explicit match for \r or \n anywhere in the
987        pattern, and if so, 7.0/46 no longer applies. As part of this change,
988        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
989        pattern has explicit CR or LF references.
990    
991    29. Added (*CR) etc for changing newline setting at start of pattern.
992    
993    
994    Version 7.2 19-Jun-07
995    ---------------------
996    
997     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
998        which is apparently normally available under Windows.
999    
1000     2. Re-jig the pcregrep tests with different newline settings in an attempt
1001        to make them independent of the local environment's newline setting.
1002    
1003     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1004    
1005     4. Some of the "internals" tests were previously cut out when the link size
1006        was not 2, because the output contained actual offsets. The recent new
1007        "Z" feature of pcretest means that these can be cut out, making the tests
1008        usable with all link sizes.
1009    
1010     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1011        stack recursion. This gives a massive performance boost under BSD, but just
1012        a small improvement under Linux. However, it saves one field in the frame
1013        in all cases.
1014    
1015     6. Added more features from the forthcoming Perl 5.10:
1016    
1017        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1018            recursion call. It refers to the nth most recently opened parentheses.
1019    
1020        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1021            to be opened parentheses.
1022    
1023        (c) Conditions that refer to capturing parentheses can be specified
1024            relatively, for example, (?(-2)... or (?(+3)...
1025    
1026        (d) \K resets the start of the current match so that everything before
1027            is not part of it.
1028    
1029        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1030    
1031        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1032            reference syntax.
1033    
1034        (g) (?| introduces a group in which the numbering of parentheses in each
1035            alternative starts with the same number.
1036    
1037        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1038    
1039     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1040        PCRE_INFO_JCHANGED.
1041    
1042     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1043        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1044        for detecting groups that can match an empty string.
1045    
1046     9. A pattern with a very large number of alternatives (more than several
1047        hundred) was running out of internal workspace during the pre-compile
1048        phase, where pcre_compile() figures out how much memory will be needed. A
1049        bit of new cunning has reduced the workspace needed for groups with
1050        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1051        workspace instead of running out of the 4096 that are available.
1052    
1053    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1054    
1055    11. Applied patch from Google to remove an optimization that didn't quite work.
1056        The report of the bug said:
1057    
1058          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1059          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1060          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1061    
1062    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1063        it matched the wrong number of bytes.
1064    
1065    
1066    Version 7.1 24-Apr-07
1067    ---------------------
1068    
1069     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1070        that is more "standard", making use of automake and other Autotools. There
1071        is some re-arrangement of the files and adjustment of comments consequent
1072        on this.
1073    
1074     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1075        for recursive directory scanning broke on some systems because the files
1076        are not scanned in any specific order and on different systems the order
1077        was different. A call to "sort" has been inserted into RunGrepTest for the
1078        approprate test as a short-term fix. In the longer term there may be an
1079        alternative.
1080    
1081     3. I had an email from Eric Raymond about problems translating some of PCRE's
1082        man pages to HTML (despite the fact that I distribute HTML pages, some
1083        people do their own conversions for various reasons). The problems
1084        concerned the use of low-level troff macros .br and .in. I have therefore
1085        removed all such uses from the man pages (some were redundant, some could
1086        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1087        HTML has been updated to handle .nf/.fi and to complain if it encounters
1088        .br or .in.
1089    
1090     4. Updated comments in configure.ac that get placed in config.h.in and also
1091        arranged for config.h to be included in the distribution, with the name
1092        config.h.generic, for the benefit of those who have to compile without
1093        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1094    
1095     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1096        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1097        makevp.bat for the current PCRE, using the additional files
1098        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1099    
1100     6. A Windows user reported a minor discrepancy with test 2, which turned out
1101        to be caused by a trailing space on an input line that had got lost in his
1102        copy. The trailing space was an accident, so I've just removed it.
1103    
1104     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1105        that is needed.
1106    
1107     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1108        as "const" (a) because they are and (b) because it helps the PHP
1109        maintainers who have recently made a script to detect big data structures
1110        in the php code that should be moved to the .rodata section. I remembered
1111        to update Builducptable as well, so it won't revert if ucptable.h is ever
1112        re-created.
1113    
1114     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1115        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1116        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1117        support is not required. This saves 1.5-2K of code, which is important in
1118        some applications.
1119    
1120        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1121        so as not to refer to the tables, even though these functions will never be
1122        called when UTF-8 support is disabled. Otherwise there are problems with a
1123        shared library.
1124    
1125    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1126    
1127        (a) It was defining its arguments as char * instead of void *.
1128    
1129        (b) It was assuming that all moves were upwards in memory; this was true
1130            a long time ago when I wrote it, but is no longer the case.
1131    
1132        The emulated memove() is provided for those environments that have neither
1133        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1134        is clearly not the case, as these two bugs were recently reported.
1135    
1136    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1137        and Detrail to create the HTML documentation, the .txt form of the man
1138        pages, and it removes trailing spaces from listed files. It also creates
1139        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1140        case, it wraps all the #defines with #ifndefs. This script should be run
1141        before "make dist".
1142    
1143    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1144        with Unicode property support.
1145    
1146        (a) For a maximizing quantifier, if the two different cases of the
1147            character were of different lengths in their UTF-8 codings (there are
1148            some cases like this - I found 11), and the matching function had to
1149            back up over a mixture of the two cases, it incorrectly assumed they
1150            were both the same length.
1151    
1152        (b) When PCRE was configured to use the heap rather than the stack for
1153            recursion during matching, it was not correctly preserving the data for
1154            the other case of a UTF-8 character when checking ahead for a match
1155            while processing a minimizing repeat. If the check also involved
1156            matching a wide character, but failed, corruption could cause an
1157            erroneous result when trying to check for a repeat of the original
1158            character.
1159    
1160    13. Some tidying changes to the testing mechanism:
1161    
1162        (a) The RunTest script now detects the internal link size and whether there
1163            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1164            values substituted by "configure". (The RunGrepTest script already did
1165            this for UTF-8.) The configure.ac script no longer substitutes the
1166            relevant variables.
1167    
1168        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1169            with length and offset values. This means that the output is different
1170            for different internal link sizes. Test 2 is skipped for link sizes
1171            other than 2 because of this, bypassing the problem. Unfortunately,
1172            there was also a test in test 3 (the locale tests) that used /B and
1173            failed for link sizes other than 2. Rather than cut the whole test out,
1174            I have added a new /Z option to pcretest that replaces the length and
1175            offset values with spaces. This is now used to make test 3 independent
1176            of link size. (Test 2 will be tidied up later.)
1177    
1178    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1179        segmentation fault instead of returning the appropriate error message.
1180    
1181    15. In multiline mode when the newline sequence was set to "any", the pattern
1182        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1183        This doesn't seem right; it now treats the CRLF combination as the line
1184        ending, and so does not match in that case. It's only a pattern such as ^$
1185        that would hit this one: something like ^ABC$ would have failed after \r
1186        and then tried again after \r\n.
1187    
1188    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1189        in an attempt to make files that differ only in their line terminators
1190        compare equal. This works on Linux.
1191    
1192    17. Under certain error circumstances pcregrep might try to free random memory
1193        as it exited. This is now fixed, thanks to valgrind.
1194    
1195    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1196        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1197        was because its rules for how to advance for /g after matching an empty
1198        string at the end of a line did not allow for this case. They now check for
1199        it specially.
1200    
1201    20. pcretest is supposed to handle patterns and data of any length, by
1202        extending its buffers when necessary. It was getting this wrong when the
1203        buffer for a data line had to be extended.
1204    
1205    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1206        CRLF as a newline sequence.
1207    
1208    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1209        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1210        I have nevertheless tidied it up.
1211    
1212    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1213    
1214    24. Added a man page for pcre-config.
1215    
1216    
1217    Version 7.0 19-Dec-06
1218    ---------------------
1219    
1220     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1221        moving to gcc 4.1.1.
1222    
1223     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1224        sys/time.h, which is documented as needed for this function. It doesn't
1225        seem to matter on Linux, but it showed up on some releases of OS X.
1226    
1227     3. It seems that there are systems where bytes whose values are greater than
1228        127 match isprint() in the "C" locale. The "C" locale should be the
1229        default when a C program starts up. In most systems, only ASCII printing
1230        characters match isprint(). This difference caused the output from pcretest
1231        to vary, making some of the tests fail. I have changed pcretest so that:
1232    
1233        (a) When it is outputting text in the compiled version of a pattern, bytes
1234            other than 32-126 are always shown as hex escapes.
1235    
1236        (b) When it is outputting text that is a matched part of a subject string,
1237            it does the same, unless a different locale has been set for the match
1238            (using the /L modifier). In this case, it uses isprint() to decide.
1239    
1240     4. Fixed a major bug that caused incorrect computation of the amount of memory
1241        required for a compiled pattern when options that changed within the
1242        pattern affected the logic of the preliminary scan that determines the
1243        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1244        that the computed length was too small. The symptoms of this bug were
1245        either the PCRE error "internal error: code overflow" from pcre_compile(),
1246        or a glibc crash with a message such as "pcretest: free(): invalid next
1247        size (fast)". Examples of patterns that provoked this bug (shown in
1248        pcretest format) are:
1249    
1250          /(?-x: )/x
1251          /(?x)(?-x: \s*#\s*)/
1252          /((?i)[\x{c0}])/8
1253          /(?i:[\x{c0}])/8
1254    
1255        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1256        is now done differently.
1257    
1258     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1259        wrapper classes; (b) implement a new function in the C++ scanner that is
1260        more efficient than the old way of doing things because it avoids levels of
1261        recursion in the regex matching; (c) add a paragraph to the documentation
1262        for the FullMatch() function.
1263    
1264     6. The escape sequence \n was being treated as whatever was defined as
1265        "newline". Not only was this contrary to the documentation, which states
1266        that \n is character 10 (hex 0A), but it also went horribly wrong when
1267        "newline" was defined as CRLF. This has been fixed.
1268    
1269     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1270        was being set to -1 for the "end of line" case (supposedly a value that no
1271        character can have). Though this value is never used (the check for end of
1272        line is "zero bytes in current character"), it caused compiler complaints.
1273        I've changed it to 0xffffffff.
1274    
1275     8. In pcre_version.c, the version string was being built by a sequence of
1276        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1277        string (as it is for production releases) called a macro with an empty
1278        argument. The C standard says the result of this is undefined. The gcc
1279        compiler treats it as an empty string (which was what was wanted) but it is
1280        reported that Visual C gives an error. The source has been hacked around to
1281        avoid this problem.
1282    
1283     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1284        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1285        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1286        of them did).
1287    
1288    10. Originally, pcretest opened its input and output without "b"; then I was
1289        told that "b" was needed in some environments, so it was added for release
1290        5.0 to both the input and output. (It makes no difference on Unix-like
1291        systems.) Later I was told that it is wrong for the input on Windows. I've
1292        now abstracted the modes into two macros, to make it easier to fiddle with
1293        them, and removed "b" from the input mode under Windows.
1294    
1295    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1296    
1297    12. Added -help and --help to pcretest as an official way of being reminded
1298        of the options.
1299    
1300    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1301        and pcrecpp.cc because they annoy compilers at high warning levels.
1302    
1303    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1304    
1305    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1306        scripts are not C programs :-) and which was not noticed because it works
1307        on Linux.
1308    
1309    16. pcretest is supposed to handle any length of pattern and data line (as one
1310        line or as a continued sequence of lines) by extending its input buffer if
1311        necessary. This feature was broken for very long pattern lines, leading to
1312        a string of junk being passed to pcre_compile() if the pattern was longer
1313        than about 50K.
1314    
1315    17. I have done a major re-factoring of the way pcre_compile() computes the
1316        amount of memory needed for a compiled pattern. Previously, there was code
1317        that made a preliminary scan of the pattern in order to do this. That was
1318        OK when PCRE was new, but as the facilities have expanded, it has become
1319        harder and harder to keep it in step with the real compile phase, and there
1320        have been a number of bugs (see for example, 4 above). I have now found a
1321        cunning way of running the real compile function in a "fake" mode that
1322        enables it to compute how much memory it would need, while actually only
1323        ever using a few hundred bytes of working memory and without too many
1324        tests of the mode. This should make future maintenance and development
1325        easier. A side effect of this work is that the limit of 200 on the nesting
1326        depth of parentheses has been removed (though this was never a serious
1327        limitation, I suspect). However, there is a downside: pcre_compile() now
1328        runs more slowly than before (30% or more, depending on the pattern). I
1329        hope this isn't a big issue. There is no effect on runtime performance.
1330    
1331    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1332        newline (only possible for the last line of a file) and it was a
1333        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1334    
1335    19. Added additional timing features to pcretest. (1) The -tm option now times
1336        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1337        separate command line item, by a number that specifies the number of
1338        repeats to use when timing. The default is 50000; this gives better
1339        precision, but takes uncomfortably long for very large patterns.
1340    
1341    20. Extended pcre_study() to be more clever in cases where a branch of a
1342        subpattern has no definite first character. For example, (a*|b*)[cd] would
1343        previously give no result from pcre_study(). Now it recognizes that the
1344        first character must be a, b, c, or d.
1345    
1346    21. There was an incorrect error "recursive call could loop indefinitely" if
1347        a subpattern (or the entire pattern) that was being tested for matching an
1348        empty string contained only one non-empty item after a nested subpattern.
1349        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1350        incorrectly, because the \d was being skipped in the check.
1351    
1352    22. The pcretest program now has a new pattern option /B and a command line
1353        option -b, which is equivalent to adding /B to every pattern. This causes
1354        it to show the compiled bytecode, without the additional information that
1355        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1356        is the same as /B/I).
1357    
1358    23. A new optimization is now able automatically to treat some sequences such
1359        as a*b as a*+b. More specifically, if something simple (such as a character
1360        or a simple class like \d) has an unlimited quantifier, and is followed by
1361        something that cannot possibly match the quantified thing, the quantifier
1362        is automatically "possessified".
1363    
1364    24. A recursive reference to a subpattern whose number was greater than 39
1365        went wrong under certain circumstances in UTF-8 mode. This bug could also
1366        have affected the operation of pcre_study().
1367    
1368    25. Realized that a little bit of performance could be had by replacing
1369        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1370    
1371    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1372    
1373    27. Possessive quantifiers such as a++ were previously implemented by turning
1374        them into atomic groups such as ($>a+). Now they have their own opcodes,
1375        which improves performance. This includes the automatically created ones
1376        from 23 above.
1377    
1378    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1379        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1380        the first matched character to be a colon. This applied both to named and
1381        numbered groups.
1382    
1383    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1384    
1385    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1386        building PCRE on Windows easier, so I have included it in the distribution.
1387    
1388    31. There is now a check in pcretest against a ridiculously large number being
1389        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1390        loop, the loop is abandoned.
1391    
1392    32. Forward references to subpatterns in conditions such as (?(2)...) where
1393        subpattern 2 is defined later cause pcre_compile() to search forwards in
1394        the pattern for the relevant set of parentheses. This search went wrong
1395        when there were unescaped parentheses in a character class, parentheses
1396        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1397    
1398    33. "Subroutine" calls and backreferences were previously restricted to
1399        referencing subpatterns earlier in the regex. This restriction has now
1400        been removed.
1401    
1402    34. Added a number of extra features that are going to be in Perl 5.10. On the
1403        whole, these are just syntactic alternatives for features that PCRE had
1404        previously implemented using the Python syntax or my own invention. The
1405        other formats are all retained for compatibility.
1406    
1407        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1408            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1409            also .NET compatible.
1410    
1411        (b) A recursion or subroutine call to a named group can now be defined as
1412            (?&name) as well as (?P>name).
1413    
1414        (c) A backreference to a named group can now be defined as \k<name> or
1415            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1416            5.10, are also .NET compatible.
1417    
1418        (d) A conditional reference to a named group can now use the syntax
1419            (?(<name>) or (?('name') as well as (?(name).
1420    
1421        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1422            groups (named and numbered) that are never evaluated inline, but can be
1423            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1424            is always false. There may be only one alternative in such a group.
1425    
1426        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1427            as the simple (?(R). The condition is true only if the most recent
1428            recursion is that of the given number or name. It does not search out
1429            through the entire recursion stack.
1430    
1431        (g) The escape \gN or \g{N} has been added, where N is a positive or
1432            negative number, specifying an absolute or relative reference.
1433    
1434    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1435        some "unreachable code" warnings.
1436    
1437    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1438        things, this adds five new scripts.
1439    
1440    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1441        There were also incompatibilities regarding the handling of \Q..\E inside
1442        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1443        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1444    
1445    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1446        matches an empty string, and forcibly breaks the loop. There were bugs in
1447        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1448        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1449        separate and independent bugs (that affected different cases) have been
1450        fixed.
1451    
1452    39. Refactored the code to abolish the use of different opcodes for small
1453        capturing bracket numbers. This is a tidy that I avoided doing when I
1454        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1455        The new approach is not only tidier, it makes it possible to reduce the
1456        memory needed to fix the previous bug (38).
1457    
1458    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1459        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1460        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1461        mode.
1462    
1463    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1464        report.
1465    
1466    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1467        copy construction and assignment in the C++ wrapper.
1468    
1469    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1470        couple of bugs that could have given wrong results in the "--newline=crlf"
1471        case.
1472    
1473    44. Added a number of casts and did some reorganization of signed/unsigned int
1474        variables following suggestions from Dair Grant. Also renamed the variable
1475        "this" as "item" because it is a C++ keyword.
1476    
1477    45. Arranged for dftables to add
1478    
1479          #include "pcre_internal.h"
1480    
1481        to pcre_chartables.c because without it, gcc 4.x may remove the array
1482        definition from the final binary if PCRE is built into a static library and
1483        dead code stripping is activated.
1484    
1485    46. For an unanchored pattern, if a match attempt fails at the start of a
1486        newline sequence, and the newline setting is CRLF or ANY, and the next two
1487        characters are CRLF, advance by two characters instead of one.
1488    
1489    
1490    Version 6.7 04-Jul-06
1491    ---------------------
1492    
1493     1. In order to handle tests when input lines are enormously long, pcretest has
1494        been re-factored so that it automatically extends its buffers when
1495        necessary. The code is crude, but this _is_ just a test program. The
1496        default size has been increased from 32K to 50K.
1497    
1498     2. The code in pcre_study() was using the value of the re argument before
1499        testing it for NULL. (Of course, in any sensible call of the function, it
1500        won't be NULL.)
1501    
1502     3. The memmove() emulation function in pcre_internal.h, which is used on
1503        systems that lack both memmove() and bcopy() - that is, hardly ever -
1504        was missing a "static" storage class specifier.
1505    
1506     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1507        containing an extended class (one that cannot be represented by a bitmap
1508        because it contains high-valued characters or Unicode property items, e.g.
1509        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1510        pattern, but PCRE should not loop if you do not (it no longer does).
1511        [Detail: two cases were found: (a) a repeated subpattern containing an
1512        extended class; (b) a recursive reference to a subpattern that followed a
1513        previous extended class. It wasn't skipping over the extended class
1514        correctly when UTF-8 mode was not set.]
1515    
1516     5. A negated single-character class was not being recognized as fixed-length
1517        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1518        compile error "lookbehind assertion is not fixed length".
1519    
1520     6. The RunPerlTest auxiliary script was showing an unexpected difference
1521        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1522        write a Perl script that can interpret lines of an input file either as
1523        byte characters or as UTF-8, which is what "perltest" was being required to
1524        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1525        can't do is switch easily at run time between having the "use utf8;" pragma
1526        or not. In the end, I fudged it by using the RunPerlTest script to insert
1527        "use utf8;" explicitly for the UTF-8 tests.
1528    
1529     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1530        the end of the subject string, contrary to the documentation and to what
1531        Perl does. This was true of both matching functions. Now it matches only at
1532        the start of the subject and immediately after *internal* newlines.
1533    
1534     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1535        a pointer to an int instead of a pointer to an unsigned long int. This
1536        caused problems on 64-bit systems.
1537    
1538     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1539        instance of the 'standard' template library not being so standard".
1540    
1541    10. There was no check on the number of named subpatterns nor the maximum
1542        length of a subpattern name. The product of these values is used to compute
1543        the size of the memory block for a compiled pattern. By supplying a very
1544        long subpattern name and a large number of named subpatterns, the size
1545        computation could be caused to overflow. This is now prevented by limiting
1546        the length of names to 32 characters, and the number of named subpatterns
1547        to 10,000.
1548    
1549    11. Subpatterns that are repeated with specific counts have to be replicated in
1550        the compiled pattern. The size of memory for this was computed from the
1551        length of the subpattern and the repeat count. The latter is limited to
1552        65535, but there was no limit on the former, meaning that integer overflow
1553        could in principle occur. The compiled length of a repeated subpattern is
1554        now limited to 30,000 bytes in order to prevent this.
1555    
1556    12. Added the optional facility to have named substrings with the same name.
1557    
1558    13. Added the ability to use a named substring as a condition, using the
1559        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1560        are numbers (not recommended). Forward references are permitted.
1561    
1562    14. Added forward references in named backreferences (if you see what I mean).
1563    
1564    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1565        pattern could run off the end of the subject. For example, the pattern
1566        "(?s)(.{1,5})"8 did this with the subject "ab".
1567    
1568    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1569        PCRE_CASELESS was set when matching characters that were quantified with ?
1570        or *.
1571    
1572    17. A character class other than a single negated character that had a minimum
1573        but no maximum quantifier - for example [ab]{6,} - was not handled
1574        correctly by pce_dfa_exec(). It would match only one character.
1575    
1576    18. A valid (though odd) pattern that looked like a POSIX character
1577        class but used an invalid character after [ (for example [[,abc,]]) caused
1578        pcre_compile() to give the error "Failed: internal error: code overflow" or
1579        in some cases to crash with a glibc free() error. This could even happen if
1580        the pattern terminated after [[ but there just happened to be a sequence of
1581        letters, a binary zero, and a closing ] in the memory that followed.
1582    
1583    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1584        over the years. Originally (before any Unicode support), just the bottom 8
1585        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1586        output from "man perlunicode" includes this:
1587    
1588          The regular expression compiler produces polymorphic opcodes.  That
1589          is, the pattern adapts to the data and automatically switches to
1590          the Unicode character scheme when presented with Unicode data--or
1591          instead uses a traditional byte scheme when presented with byte
1592          data.
1593    
1594        Sadly, a wide octal escape does not cause a switch, and in a string with
1595        no other multibyte characters, these octal escapes are treated as before.
1596        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1597        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1598        Unicode string.
1599    
1600        I have not perpetrated such confusion in PCRE. Up till now, it took just
1601        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1602        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1603        translate to the appropriate multibyte character.
1604    
1605    29. Applied some refactoring to reduce the number of warnings from Microsoft
1606        and Borland compilers. This has included removing the fudge introduced
1607        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1608        a warning about an unused variable.
1609    
1610    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1611        characters since release 4.0, because Perl (from release 5.004) does not.
1612        [Or at least, is documented not to: some releases seem to be in conflict
1613        with the documentation.] However, when a pattern was studied with
1614        pcre_study() and all its branches started with \s, PCRE still included VT
1615        as a possible starting character. Of course, this did no harm; it just
1616        caused an unnecessary match attempt.
1617    
1618    22. Removed a now-redundant internal flag bit that recorded the fact that case
1619        dependency changed within the pattern. This was once needed for "required
1620        byte" processing, but is no longer used. This recovers a now-scarce options
1621        bit. Also moved the least significant internal flag bit to the most-
1622        significant bit of the word, which was not previously used (hangover from
1623        the days when it was an int rather than a uint) to free up another bit for
1624        the future.
1625    
1626    23. Added support for CRLF line endings as well as CR and LF. As well as the
1627        default being selectable at build time, it can now be changed at runtime
1628        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1629        specify that it is scanning data with non-default line endings.
1630    
1631    24. Changed the definition of CXXLINK to make it agree with the definition of
1632        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1633    
1634    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1635        recursions. This makes a big different to stack usage for some patterns.
1636    
1637    26. If a subpattern containing a named recursion or subroutine reference such
1638        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1639        the space required for the compiled pattern went wrong and gave too small a
1640        value. Depending on the environment, this could lead to "Failed: internal
1641        error: code overflow at offset 49" or "glibc detected double free or
1642        corruption" errors.
1643    
1644    27. Applied patches from Google (a) to support the new newline modes and (b) to
1645        advance over multibyte UTF-8 characters in GlobalReplace.
1646    
1647    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1648        difference for some implementation of PCRE in some Windows version.
1649    
1650    29. Added some extra testing facilities to pcretest:
1651    
1652        \q<number>   in a data line sets the "match limit" value
1653        \Q<number>   in a data line sets the "match recursion limt" value
1654        -S <number>  sets the stack size, where <number> is in megabytes
1655    
1656        The -S option isn't available for Windows.
1657    
1658    
1659    Version 6.6 06-Feb-06
1660    ---------------------
1661    
1662     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1663        in pcreposix.h. I have copied the definition from pcre.h.
1664    
1665     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1666        because pcre.h is no longer a built file.
1667    
1668     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1669        not normally included in the compiled code.
1670    
1671    
1672    Version 6.5 01-Feb-06
1673    ---------------------
1674    
1675     1. When using the partial match feature with pcre_dfa_exec(), it was not
1676        anchoring the second and subsequent partial matches at the new starting
1677        point. This could lead to incorrect results. For example, with the pattern
1678        /1234/, partially matching against "123" and then "a4" gave a match.
1679    
1680     2. Changes to pcregrep:
1681    
1682        (a) All non-match returns from pcre_exec() were being treated as failures
1683            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1684            error message is output. Some extra information is given for the
1685            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1686            probably the only errors that are likely to be caused by users (by
1687            specifying a regex that has nested indefinite repeats, for instance).
1688            If there are more than 20 of these errors, pcregrep is abandoned.
1689    
1690        (b) A binary zero was treated as data while matching, but terminated the
1691            output line if it was written out. This has been fixed: binary zeroes
1692            are now no different to any other data bytes.
1693    
1694        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1695            used to set a locale for matching. The --locale=xxxx long option has
1696            been added (no short equivalent) to specify a locale explicitly on the
1697            pcregrep command, overriding the environment variables.
1698    
1699        (d) When -B was used with -n, some line numbers in the output were one less
1700            than they should have been.
1701    
1702        (e) Added the -o (--only-matching) option.
1703    
1704        (f) If -A or -C was used with -c (count only), some lines of context were
1705            accidentally printed for the final match.
1706    
1707        (g) Added the -H (--with-filename) option.
1708    
1709        (h) The combination of options -rh failed to suppress file names for files
1710            that were found from directory arguments.
1711    
1712        (i) Added the -D (--devices) and -d (--directories) options.
1713    
1714        (j) Added the -F (--fixed-strings) option.
1715    
1716        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1717    
1718        (l) Added the --colo(u)r option.
1719    
1720        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1721            is not present by default.
1722    
1723     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1724        items such as (?R) or (?1), when the recursion could match a number of
1725        alternatives. If it matched one of the alternatives, but subsequently,
1726        outside the recursion, there was a failure, the code tried to back up into
1727        the recursion. However, because of the way PCRE is implemented, this is not
1728        possible, and the result was an incorrect result from the match.
1729    
1730        In order to prevent this happening, the specification of recursion has
1731        been changed so that all such subpatterns are automatically treated as
1732        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1733    
1734     4. I had overlooked the fact that, in some locales, there are characters for
1735        which isalpha() is true but neither isupper() nor islower() are true. In
1736        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1737        and ordfeminine) are like this. This affected the treatment of \w and \W
1738        when they appeared in character classes, but not when they appeared outside
1739        a character class. The bit map for "word" characters is now created
1740        separately from the results of isalnum() instead of just taking it from the
1741        upper, lower, and digit maps. (Plus the underscore character, of course.)
1742    
1743     5. The above bug also affected the handling of POSIX character classes such as
1744        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1745        permanent tables. Instead, the bit maps for such a class were previously
1746        created as the appropriate unions of the upper, lower, and digit bitmaps.
1747        Now they are created by subtraction from the [[:word:]] class, which has
1748        its own bitmap.
1749    
1750     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1751        It is created by subtracting the vertical space characters (\x09, \x0a,
1752        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1753        subtraction was done in the overall bitmap for a character class, meaning
1754        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1755        be recognized. This bug has been fixed.
1756    
1757     7. Patches from the folks at Google:
1758    
1759          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1760          real life, but is still worth protecting against".
1761    
1762          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1763          regular expressions".
1764    
1765          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1766          have it.
1767    
1768          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1769          "configure" and the latter not, in order to fix a problem somebody had
1770          with compiling the Arg class on HP-UX.
1771    
1772          (e) Improve the error-handling of the C++ wrapper a little bit.
1773    
1774          (f) New tests for checking recursion limiting.
1775    
1776     8. The pcre_memmove() function, which is used only if the environment does not
1777        have a standard memmove() function (and is therefore rarely compiled),
1778        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1779        returning a result (though PCRE never actually uses the result).
1780    
1781     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1782        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1783        returned instead of calling malloc() with an overflowing number that would
1784        most likely cause subsequent chaos.
1785    
1786    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1787    
1788    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1789        with this option is matched, the nmatch and pmatch options of regexec() are
1790        ignored.
1791    
1792    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1793        provided in case anyone wants to the the POSIX interface with UTF-8
1794        strings.
1795    
1796    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1797        C++ linking (needed for some HP-UX environments).
1798    
1799    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1800        (unused parameter) and in the pcre_printint() function (omitted "default"
1801        switch label when the default is to do nothing).
1802    
1803    15. Added some code to make it possible, when PCRE is compiled as a C++
1804        library, to replace subject pointers for pcre_exec() with a smart pointer
1805        class, thus making it possible to process discontinuous strings.
1806    
1807    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1808        much the same function. They were added by different people who were trying
1809        to make PCRE easy to compile on non-Unix systems. It has been suggested
1810        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1811        for compiling on Windows systems. I have therefore replaced it with
1812        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1813        defaults to "extern" for C or "extern C" for C++, which works fine on
1814        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1815        SCOPE with something explicit in config.h. In addition:
1816    
1817        (a) pcreposix.h still had just "extern" instead of either of these macros;
1818            I have replaced it with PCRE_DATA_SCOPE.
1819    
1820        (b) Functions such as _pcre_xclass(), which are internal to the library,
1821            but external in the C sense, all had PCRE_EXPORT in their definitions.
1822            This is apparently wrong for the Windows case, so I have removed it.
1823            (It makes no difference on Unix-like systems.)
1824    
1825    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1826        of recursive calls to match(). This is different to MATCH_LIMIT because
1827        that limits the total number of calls to match(), not all of which increase
1828        the depth of recursion. Limiting the recursion depth limits the amount of
1829        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1830        when PCRE is compiled, and changed at run time. A patch from Google adds
1831        this functionality to the C++ interface.
1832    
1833    18. Changes to the handling of Unicode character properties:
1834    
1835        (a) Updated the table to Unicode 4.1.0.
1836    
1837        (b) Recognize characters that are not in the table as "Cn" (undefined).
1838    
1839        (c) I revised the way the table is implemented to a much improved format
1840            which includes recognition of ranges. It now supports the ranges that
1841            are defined in UnicodeData.txt, and it also amalgamates other
1842            characters into ranges. This has reduced the number of entries in the
1843            table from around 16,000 to around 3,000, thus reducing its size
1844            considerably. I realized I did not need to use a tree structure after
1845            all - a binary chop search is just as efficient. Having reduced the
1846            number of entries, I extended their size from 6 bytes to 8 bytes to
1847            allow for more data.
1848    
1849        (d) Added support for Unicode script names via properties such as \p{Han}.
1850    
1851    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1852        matching that character.
1853    
1854    20. When matching a repeated Unicode property with a minimum greater than zero,
1855        (for example \pL{2,}), PCRE could look past the end of the subject if it
1856        reached it while seeking the minimum number of characters. This could
1857        happen only if some of the characters were more than one byte long, because
1858        there is a check for at least the minimum number of bytes.
1859    
1860    21. Refactored the implementation of \p and \P so as to be more general, to
1861        allow for more different types of property in future. This has changed the
1862        compiled form incompatibly. Anybody with saved compiled patterns that use
1863        \p or \P will have to recompile them.
1864    
1865    22. Added "Any" and "L&" to the supported property types.
1866    
1867    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1868        but give a compile time error if the value is greater than 0xff.
1869    
1870    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1871        accidentally not being installed or uninstalled.
1872    
1873    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1874        made were to insert the current release number. This seemed silly, because
1875        it made things harder for people building PCRE on systems that don't run
1876        "configure". I have turned pcre.h into a distributed file, no longer built
1877        by "configure", with the version identification directly included. There is
1878        no longer a pcre.h.in file.
1879    
1880        However, this change necessitated a change to the pcre-config script as
1881        well. It is built from pcre-config.in, and one of the substitutions was the
1882        release number. I have updated configure.ac so that ./configure now finds
1883        the release number by grepping pcre.h.
1884    
1885    26. Added the ability to run the tests under valgrind.
1886    
1887    
1888    Version 6.4 05-Sep-05
1889    ---------------------
1890    
1891     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1892        "--" to be printed when multiple files were scanned, even when none of the
1893        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1894        consider it to be a bug, and have restored the previous behaviour.
1895    
1896     2. A couple of code tidies to get rid of compiler warnings.
1897    
1898     3. The pcretest program used to cheat by referring to symbols in the library
1899        whose names begin with _pcre_. These are internal symbols that are not
1900        really supposed to be visible externally, and in some environments it is
1901        possible to suppress them. The cheating is now confined to including
1902        certain files from the library's source, which is a bit cleaner.
1903    
1904     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1905        file's purpose clearer.
1906    
1907     5. Reorganized pcre_ucp_findchar().
1908    
1909    
1910    Version 6.3 15-Aug-05
1911    ---------------------
1912    
1913     1. The file libpcre.pc.in did not have general read permission in the tarball.
1914    
1915     2. There were some problems when building without C++ support:
1916    
1917        (a) If C++ support was not built, "make install" and "make test" still
1918            tried to test it.
1919    
1920        (b) There were problems when the value of CXX was explicitly set. Some
1921            changes have been made to try to fix these, and ...
1922    
1923        (c) --disable-cpp can now be used to explicitly disable C++ support.
1924    
1925        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1926            backslash in a target when C++ was disabled. This confuses some
1927            versions of "make", apparently. Using an intermediate variable solves
1928            this. (Same for CPP_LOBJ.)
1929    
1930     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1931        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1932        necessary on certain architectures.
1933    
1934     4. Added a setting of -export-symbols-regex to the link command to remove
1935        those symbols that are exported in the C sense, but actually are local
1936        within the library, and not documented. Their names all begin with
1937        "_pcre_". This is not a perfect job, because (a) we have to except some
1938        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1939        available (and never for static libraries). I have made a note to try to
1940        find a way round (a) in the future.
1941    
1942    
1943    Version 6.2 01-Aug-05
1944    ---------------------
1945    
1946     1. There was no test for integer overflow of quantifier values. A construction
1947        such as {1111111111111111} would give undefined results. What is worse, if
1948        a minimum quantifier for a parenthesized subpattern overflowed and became
1949        negative, the calculation of the memory size went wrong. This could have
1950        led to memory overwriting.
1951    
1952     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1953    
1954     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1955        operating environments where this matters.
1956    
1957     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1958        PCRE options from within the C++ wrapper.
1959    
1960     5. Named capturing subpatterns were not being correctly counted when a pattern
1961        was compiled. This caused two problems: (a) If there were more than 100
1962        such subpatterns, the calculation of the memory needed for the whole
1963        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1964        back references of the form \12, where the number was greater than 9, were
1965        not recognized as back references, even though there were sufficient
1966        previous subpatterns.
1967    
1968     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1969        versions of gcc, e.g. 2.95.4.
1970    
1971    
1972    Version 6.1 21-Jun-05
1973    ---------------------
1974    
1975     1. There was one reference to the variable "posix" in pcretest.c that was not
1976        surrounded by "#if !defined NOPOSIX".
1977    
1978     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1979        the cross-check on the old pcre_info() function, for the benefit of the
1980        cut-down version of PCRE that is currently imported into Exim.
1981    
1982     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1983        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1984        patterns that start (?i) but I don't think that matters. The use of (?i) is
1985        just an example; this all applies to the other options as well.
1986    
1987     4. Since libtool seems to echo the compile commands it is issuing, the output
1988        from "make" can be reduced a bit by putting "@" in front of each libtool
1989        compile command.
1990    
1991     5. Patch from the folks at Google for configure.in to be a bit more thorough
1992        in checking for a suitable C++ installation before trying to compile the
1993        C++ stuff. This should fix a reported problem when a compiler was present,
1994        but no suitable headers.
1995    
1996     6. The man pages all had just "PCRE" as their title. I have changed them to
1997        be the relevant file name. I have also arranged that these names are
1998        retained in the file doc/pcre.txt, which is a concatenation in text format
1999        of all the man pages except the little individual ones for each function.
2000    
2001     7. The NON-UNIX-USE file had not been updated for the different set of source
2002        files that come with release 6. I also added a few comments about the C++
2003        wrapper.
2004    
2005    
2006    Version 6.0 07-Jun-05
2007    ---------------------
2008    
2009     1. Some minor internal re-organization to help with my DFA experiments.
2010    
2011     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2012        didn't matter for the library itself when fully configured, but did matter
2013        when compiling without UCP support, or within Exim, where the ucp files are
2014        not imported.
2015    
2016     3. Refactoring of the library code to split up the various functions into
2017        different source modules. The addition of the new DFA matching code (see
2018        below) to a single monolithic source would have made it really too
2019        unwieldy, quite apart from causing all the code to be include in a
2020        statically linked application, when only some functions are used. This is
2021        relevant even without the DFA addition now that patterns can be compiled in
2022        one application and matched in another.
2023    
2024        The downside of splitting up is that there have to be some external
2025        functions and data tables that are used internally in different modules of
2026        the library but which are not part of the API. These have all had their
2027        names changed to start with "_pcre_" so that they are unlikely to clash
2028        with other external names.
2029    
2030     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2031        a different (DFA) algorithm. Although it is slower than the original
2032        function, it does have some advantages for certain types of matching
2033        problem.
2034    
2035     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2036        including restarting after a partial match.
2037    
2038     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2039        defined when compiling for Windows was sent to me. I have put it into the
2040        code, though I have no means of testing or verifying it.
2041    
2042     7. Added the pcre_refcount() auxiliary function.
2043    
2044     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2045        match before or at the first newline in the subject string. In pcretest,
2046        the /f option on a pattern can be used to set this.
2047    
2048     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2049        would behave wrongly. This has been present in PCRE since release 4.0.
2050    
2051    10. A number of changes to the pcregrep command:
2052    
2053        (a) Refactored how -x works; insert ^(...)$ instead of setting
2054            PCRE_ANCHORED and checking the length, in preparation for adding
2055            something similar for -w.
2056    
2057        (b) Added the -w (match as a word) option.
2058    
2059        (c) Refactored the way lines are read and buffered so as to have more
2060            than one at a time available.
2061    
2062        (d) Implemented a pcregrep test script.
2063    
2064        (e) Added the -M (multiline match) option. This allows patterns to match
2065            over several lines of the subject. The buffering ensures that at least
2066            8K, or the rest of the document (whichever is the shorter) is available
2067            for matching (and similarly the previous 8K for lookbehind assertions).
2068    
2069        (f) Changed the --help output so that it now says
2070    
2071              -w, --word-regex(p)
2072    
2073            instead of two lines, one with "regex" and the other with "regexp"
2074            because that confused at least one person since the short forms are the
2075            same. (This required a bit of code, as the output is generated
2076            automatically from a table. It wasn't just a text change.)
2077    
2078        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2079            option but starts with a hyphen. Could be a pattern or a path name
2080            starting with a hyphen, for instance.
2081    
2082        (h) "-" can be given as a file name to represent stdin.
2083    
2084        (i) When file names are being printed, "(standard input)" is used for
2085            the standard input, for compatibility with GNU grep. Previously
2086            "<stdin>" was used.
2087    
2088        (j) The option --label=xxx can be used to supply a name to be used for
2089            stdin when file names are being printed. There is no short form.
2090    
2091        (k) Re-factored the options decoding logic because we are going to add
2092            two more options that take data. Such options can now be given in four
2093            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2094    
2095        (l) Added the -A, -B, and -C options for requesting that lines of context
2096            around matches be printed.
2097    
2098        (m) Added the -L option to print the names of files that do not contain
2099            any matching lines, that is, the complement of -l.
2100    
2101        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2102            continue to scan other files.
2103    
2104        (o) The -s option was incorrectly implemented. For compatibility with other
2105            greps, it now suppresses the error message for a non-existent or non-
2106            accessible file (but not the return code). There is a new option called
2107            -q that suppresses the output of matching lines, which was what -s was
2108            previously doing.
2109    
2110        (p) Added --include and --exclude options to specify files for inclusion
2111            and exclusion when recursing.
2112    
2113    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2114        Hopefully, it now does.
2115    
2116    12. Missing cast in pcre_study().
2117    
2118    13. Added an "uninstall" target to the makefile.
2119    
2120    14. Replaced "extern" in the function prototypes in Makefile.in with
2121        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2122        world, but is set differently for Windows.
2123    
2124    15. Added a second compiling function called pcre_compile2(). The only
2125        difference is that it has an extra argument, which is a pointer to an
2126        integer error code. When there is a compile-time failure, this is set
2127        non-zero, in addition to the error test pointer being set to point to an
2128        error message. The new argument may be NULL if no error number is required
2129        (but then you may as well call pcre_compile(), which is now just a
2130        wrapper). This facility is provided because some applications need a
2131        numeric error indication, but it has also enabled me to tidy up the way
2132        compile-time errors are handled in the POSIX wrapper.
2133    
2134    16. Added VPATH=.libs to the makefile; this should help when building with one
2135        prefix path and installing with another. (Or so I'm told by someone who
2136        knows more about this stuff than I do.)
2137    
2138    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2139        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2140        match everything, including newlines. This is not POSIX-compatible, but
2141        somebody wanted the feature. From pcretest it can be activated by using
2142        both the P and the s flags.
2143    
2144    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2145    
2146    19. libpcre.pc was being incorrectly installed as executable.
2147    
2148    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2149        it now also looks for '\r' so that it will work unmodified on Windows.
2150    
2151    21. Added Google's contributed C++ wrapper to the distribution.
2152    
2153    22. Added some untidy missing memory free() calls in pcretest, to keep
2154        Electric Fence happy when testing.
2155    
2156    
2157    
2158    Version 5.0 13-Sep-04
2159    ---------------------
2160    
2161     1. Internal change: literal characters are no longer packed up into items
2162        containing multiple characters in a single byte-string. Each character
2163        is now matched using a separate opcode. However, there may be more than one
2164        byte in the character in UTF-8 mode.
2165    
2166     2. The pcre_callout_block structure has two new fields: pattern_position and
2167        next_item_length. These contain the offset in the pattern to the next match
2168        item, and its length, respectively.
2169    
2170     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2171        insertion of callouts before each pattern item. Added the /C option to
2172        pcretest to make use of this.
2173    
2174     4. On the advice of a Windows user, the lines
2175    
2176          #if defined(_WIN32) || defined(WIN32)
2177          _setmode( _fileno( stdout ), 0x8000 );
2178          #endif  /* defined(_WIN32) || defined(WIN32) */
2179    
2180        have been added to the source of pcretest. This apparently does useful
2181        magic in relation to line terminators.
2182    
2183     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2184        for the benefit of those environments where the "b" makes a difference.
2185    
2186     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2187        to know about it. I have put a hack into configure.in that adds in code
2188        to set GCC=yes if CC=icc. This seems to end up at a point in the
2189        generated configure script that is early enough to affect the setting of
2190        compiler options, which is what is needed, but I have no means of testing
2191        whether it really works. (The user who reported this had patched the
2192        generated configure script, which of course I cannot do.)
2193    
2194        LATER: After change 22 below (new libtool files), the configure script
2195        seems to know about icc (and also ecc). Therefore, I have commented out
2196        this hack in configure.in.
2197    
2198     7. Added support for pkg-config (2 patches were sent in).
2199    
2200     8. Negated POSIX character classes that used a combination of internal tables
2201        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2202        [[:^ascii]]. Typically, they would match almost any characters. The other
2203        POSIX classes were not broken in this way.
2204    
2205     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2206        to find the match, as PCRE was deluded into thinking that the match had to
2207        start at the start point or following a newline. The same bug applied to
2208        patterns with negative forward assertions or any backward assertions
2209        preceding ".*" at the start, unless the pattern required a fixed first
2210        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2211    
2212    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2213        starting at the last subject character, bytes beyond the end of the subject
2214        string were read.
2215    
2216    11. Renamed the variable "class" as "classbits" to make life easier for C++
2217        users. (Previously there was a macro definition, but it apparently wasn't
2218        enough.)
2219    
2220    12. Added the new field "tables" to the extra data so that tables can be passed
2221        in at exec time, or the internal tables can be re-selected. This allows
2222        a compiled regex to be saved and re-used at a later time by a different
2223        program that might have everything at different addresses.
2224    
2225    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2226        -R library as well as a -L library.
2227    
2228    14. The debugging options of pcretest (-d on the command line or D on a
2229        pattern) showed incorrect output for anything following an extended class
2230        that contained multibyte characters and which was followed by a quantifier.
2231    
2232    15. Added optional support for general category Unicode character properties
2233        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2234        support. It adds about 90K to the size of the library. The meanings of the
2235        inbuilt class escapes such as \d and \s have NOT been changed.
2236    
2237    16. Updated pcredemo.c to include calls to free() to release the memory for the
2238        compiled pattern.
2239    
2240    17. The generated file chartables.c was being created in the source directory
2241        instead of in the building directory. This caused the build to fail if the
2242        source directory was different from the building directory, and was
2243        read-only.
2244    
2245    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2246        file. No doubt somebody will tell me if they don't make sense... Also added
2247        Dan Mooney's comments about building on OpenVMS.
2248    
2249    19. Added support for partial matching via the PCRE_PARTIAL option for
2250        pcre_exec() and the \P data escape in pcretest.
2251    
2252    20. Extended pcretest with 3 new pattern features:
2253    
2254        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2255              write the compiled pattern to the file whose name is "rest-of-line".
2256              This is a straight binary dump of the data, with the saved pointer to
2257              the character tables forced to be NULL. The study data, if any, is
2258              written too. After writing, pcretest reads a new pattern.
2259    
2260        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2261              compiled pattern from the given file. There must not be any
2262              occurrences of "<" in the file name (pretty unlikely); if there are,
2263              pcretest will instead treat the initial "<" as a pattern delimiter.
2264              After reading in the pattern, pcretest goes on to read data lines as
2265              usual.
2266    
2267        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2268              and 16-bit fields in a compiled pattern, to simulate a pattern that
2269              was compiled on a host of opposite endianness.
2270    
2271    21. The pcre-exec() function can now cope with patterns that were compiled on
2272        hosts of opposite endianness, with this restriction:
2273    
2274          As for any compiled expression that is saved and used later, the tables
2275          pointer field cannot be preserved; the extra_data field in the arguments
2276          to pcre_exec() should be used to pass in a tables address if a value
2277          other than the default internal tables were used at compile time.
2278    
2279    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2280        now diagnosed as an error. Previously, most of the time, a negative number
2281        would have been treated as zero, but if in addition "ovector" was passed as
2282        NULL, a crash could occur.
2283    
2284    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2285        new versions from the libtool 1.5 distribution (the last one is a copy of
2286        a file called libtool.m4). This seems to have fixed the need to patch
2287        "configure" to support Darwin 1.3 (which I used to do). However, I still
2288        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2289        workstation).
2290    
2291    24. Changed the PCRE licence to be the more standard "BSD" licence.
2292    
2293    
2294    Version 4.5 01-Dec-03
2295    ---------------------
2296    
2297     1. There has been some re-arrangement of the code for the match() function so
2298        that it can be compiled in a version that does not call itself recursively.
2299        Instead, it keeps those local variables that need separate instances for
2300        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2301        needs to "recurse". Keeping track of where control must go is done by means
2302        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2303        hide most of the details from the main code, and operates only if
2304        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2305        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2306        operating.
2307    
2308        To make it easier for callers to provide specially tailored get/free
2309        functions for this usage, two new functions, pcre_stack_malloc, and
2310        pcre_stack_free, are used. They are always called in strict stacking order,
2311        and the size of block requested is always the same.
2312    
2313        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2314        PCRE has been compiled to use the stack or the heap for recursion. The
2315        -C option of pcretest uses this to show which version is compiled.
2316    
2317        A new data escape \S, is added to pcretest; it causes the amounts of store
2318        obtained and freed by both kinds of malloc/free at match time to be added
2319        to the output.
2320    
2321     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2322        what's available on my current Linux desktop machine.
2323    
2324     3. When matching a UTF-8 string, the test for a valid string at the start has
2325        been extended. If start_offset is not zero, PCRE now checks that it points
2326        to a byte that is the start of a UTF-8 character. If not, it returns
2327        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2328        this is necessary because there may be backward assertions in the pattern.
2329        When matching the same subject several times, it may save resources to use
2330        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2331    
2332     4. The code for checking the validity of UTF-8 strings has been tightened so
2333        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2334        containing "overlong sequences".
2335    
2336     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2337        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2338        should have been "&", but it just so happened that all the cases this let
2339        through by mistake were picked up later in the function.
2340    
2341     6. I had used a variable called "isblank" - this is a C99 function, causing
2342        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2343    
2344     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2345        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2346        so the version is shown; (c) stop "make test" echoing "./RunTest".
2347    
2348     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2349    
2350     9. The prototype for memmove() for systems that don't have it was using
2351        size_t, but the inclusion of the header that defines size_t was later. I've
2352        moved the #includes for the C headers earlier to avoid this.
2353    
2354    10. Added some adjustments to the code to make it easier to compiler on certain
2355        special systems:
2356    
2357          (a) Some "const" qualifiers were missing.
2358          (b) Added the macro EXPORT before all exported functions; by default this
2359              is defined to be empty.
2360          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2361              that it reads its output file name as an argument instead of writing
2362              to the standard output and assuming this can be redirected.
2363    
2364    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2365        class containing characters with values greater than 255, PCRE compilation
2366        went into a loop.
2367    
2368    12. A recursive reference to a subpattern that was within another subpattern
2369        that had a minimum quantifier of zero caused PCRE to crash. For example,
2370        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2371        recursion. If the recursively-called subpattern itself had a zero repeat,
2372        that was OK.
2373    
2374    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2375        buffer into which it was copied (for escape processing) was still set at
2376        1024, so long lines caused crashes.
2377    
2378    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2379        "internal error: code overflow...". This applied to any character class
2380        that was followed by a possessive quantifier.
2381    
2382    15. Modified the Makefile to add libpcre.la as a prerequisite for
2383        libpcreposix.la because I was told this is needed for a parallel build to
2384        work.
2385    
2386    16. If a pattern that contained .* following optional items at the start was
2387        studied, the wrong optimizing data was generated, leading to matching
2388        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2389        matching string must start with a or b or c. The correct conclusion for
2390        this pattern is that a match can start with any character.
2391    
2392    
2393    Version 4.4 13-Aug-03
2394    ---------------------
2395    
2396     1. In UTF-8 mode, a character class containing characters with values between
2397        127 and 255 was not handled correctly if the compiled pattern was studied.
2398        In fixing this, I have also improved the studying algorithm for such
2399        classes (slightly).
2400    
2401     2. Three internal functions had redundant arguments passed to them. Removal
2402        might give a very teeny performance improvement.
2403    
2404     3. Documentation bug: the value of the capture_top field in a callout is *one
2405        more than* the number of the hightest numbered captured substring.
2406    
2407     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2408        in incorrectly linking with a previously installed version. They now link
2409        explicitly with libpcre.la.
2410    
2411     5. configure.in no longer needs to recognize Cygwin specially.
2412    
2413     6. A problem in pcre.in for Windows platforms is fixed.
2414    
2415     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2416        pcretest, it used to include the size of the study block as part of its
2417        output. Unfortunately, the structure contains a field that has a different
2418        size on different hardware architectures. This meant that the tests that
2419        showed this size failed. As the block is currently always of a fixed size,
2420        this information isn't actually particularly useful in pcretest output, so
2421        I have just removed it.
2422    
2423     8. Three pre-processor statements accidentally did not start in column 1.
2424        Sadly, there are *still* compilers around that complain, even though
2425        standard C has not required this for well over a decade. Sigh.
2426    
2427     9. In pcretest, the code for checking callouts passed small integers in the
2428        callout_data field, which is a void * field. However, some picky compilers
2429        complained about the casts involved for this on 64-bit systems. Now
2430        pcretest passes the address of the small integer instead, which should get
2431        rid of the warnings.
2432    
2433    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2434        both compile and run time, and gives an error if an invalid UTF-8 sequence
2435        is found. There is a option for disabling this check in cases where the
2436        string is known to be correct and/or the maximum performance is wanted.
2437    
2438    11. In response to a bug report, I changed one line in Makefile.in from
2439    
2440            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2441        to
2442            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2443    
2444        to look similar to other lines, but I have no way of telling whether this
2445        is the right thing to do, as I do not use Windows. No doubt I'll get told
2446        if it's wrong...
2447    
2448    
2449    Version 4.3 21-May-03
2450    ---------------------
2451    
2452    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2453       Makefile.
2454    
2455    2. Some refactoring to improve the quality of the code:
2456    
2457       (i)   The utf8_table... variables are now declared "const".
2458    
2459       (ii)  The code for \cx, which used the "case flipping" table to upper case
2460             lower case letters, now just substracts 32. This is ASCII-specific,
2461             but the whole concept of \cx is ASCII-specific, so it seems
2462             reasonable.
2463    
2464       (iii) PCRE was using its character types table to recognize decimal and
2465             hexadecimal digits in the pattern. This is silly, because it handles
2466             only 0-9, a-f, and A-F, but the character types table is locale-
2467             specific, which means strange things might happen. A private
2468             table is now used for this - though it costs 256 bytes, a table is
2469             much faster than multiple explicit tests. Of course, the standard
2470             character types table is still used for matching digits in subject
2471             strings against \d.
2472    
2473       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2474             ending in _t are). So I've renamed it as ESC_tee.
2475    
2476    3. The first argument for regexec() in the POSIX wrapper should have been
2477       defined as "const".
2478    
2479    4. Changed pcretest to use malloc() for its buffers so that they can be
2480       Electric Fenced for debugging.
2481    
2482    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2483       to read one or more bytes before the start of the subject string. Often this
2484       had no effect on PCRE's behaviour, but in some circumstances it could
2485       provoke a segmentation fault.
2486    
2487    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2488       to try to read one or more bytes before the start of the subject string.
2489    
2490    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2491       UTF-8 support could misbehave in various ways if the subject string
2492       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2493       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2494       back over UTF-8 characters.)
2495    
2496    
2497    Version 4.2 14-Apr-03
2498    ---------------------
2499    
2500    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2501    
2502    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2503         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2504         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2505         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2506         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2507           and BUILD_EXEEXT
2508         Note: automatic setting of the BUILD variables is not yet working
2509         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2510           compile-time but not at link-time
2511         [LINK]: use for linking executables only
2512         make different versions for Windows and non-Windows
2513         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2514           libraries
2515         [LINK_FOR_BUILD]: new variable
2516         [OBJEXT]: use throughout
2517         [EXEEXT]: use throughout
2518         <winshared>: new target
2519         <wininstall>: new target
2520         <dftables.o>: use native compiler
2521         <dftables>: use native linker
2522         <install>: handle Windows platform correctly
2523         <clean>: ditto
2524         <check>: ditto
2525         copy DLL to top builddir before testing
2526    
2527       As part of these changes, -no-undefined was removed again. This was reported
2528       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2529       in any case.
2530    
2531    3. Some tidies to get rid of compiler warnings:
2532    
2533       . In the match_data structure, match_limit was an unsigned long int, whereas
2534         match_call_count was an int. I've made them both unsigned long ints.
2535    
2536       . In pcretest the fact that a const uschar * doesn't automatically cast to
2537         a void * provoked a warning.
2538    
2539       . Turning on some more compiler warnings threw up some "shadow" variables
2540         and a few more missing casts.
2541    
2542    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2543       option, a class that contained a single character with a value between 128
2544       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2545    
2546    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2547       option, a class that contained several characters, but with at least one
2548       whose value was between 128 and 255 caused PCRE to crash.
2549    
2550    
2551    Version 4.1 12-Mar-03
2552    ---------------------
2553    
2554    1. Compiling with gcc -pedantic found a couple of places where casts were
2555    needed, and a string in dftables.c that was longer than standard compilers are
2556    required to support.
2557    
2558    2. Compiling with Sun's compiler found a few more places where the code could
2559    be tidied up in order to avoid warnings.
2560    
2561    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2562    first of these names is deprecated in the latest Autoconf in favour of the name
2563    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2564    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2565    analogy I have changed it to CFLAGS_FOR_BUILD.
2566    
2567    4. Added -no-undefined to the linking command in the Makefile, because this is
2568    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2569    linking step for the pcreposix library.
2570    
2571    5. PCRE was failing to diagnose the case of two named groups with the same
2572    name.
2573    
2574    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2575    literal character that is needed in the subject for a match, and scans along to
2576    ensure that it is present before embarking on the full matching process. This
2577    saves time in cases of nested unlimited repeats that are never going to match.
2578    Problem: the scan can take a lot of time if the subject is very long (e.g.
2579    megabytes), thus penalizing straightforward matches. It is now done only if the
2580    amount of subject to be scanned is less than 1000 bytes.
2581    
2582    7. A lesser problem with the same optimization is that it was recording the
2583    first character of an anchored pattern as "needed", thus provoking a search
2584    right along the subject, even when the first match of the pattern was going to
2585    fail. The "needed" character is now not set for anchored patterns, unless it
2586    follows something in the pattern that is of non-fixed length. Thus, it still
2587    fulfils its original purpose of finding quick non-matches in cases of nested
2588    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2589    
2590    
2591    Version 4.0 17-Feb-03
2592    ---------------------
2593    
2594    1. If a comment in an extended regex that started immediately after a meta-item
2595    extended to the end of string, PCRE compiled incorrect data. This could lead to
2596    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2597    
2598    2. Moved to autoconf 2.53 and libtool 1.4.2.
2599    
2600    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2601    the special perltest8 script is no longer needed - all the tests can be run
2602    from a single perltest script.
2603    
2604    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2605    by \s. It has now been removed in PCRE. This means it isn't recognized as
2606    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2607    class [:space:] *does* include VT, thereby creating a mess.
2608    
2609    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2610    space and tab.
2611    
2612    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2613    its new features into the main test script, reducing the number of scripts.
2614    
2615    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2616    were backward compatible, and made the (?i) apply to the whole pattern, as if
2617    /i were given. Now it behaves more logically, and applies the option setting
2618    only to what follows. PCRE has been changed to follow suit. However, if it
2619    finds options settings right at the start of the pattern, it extracts them into
2620    the global options, as before. Thus, they show up in the info data.
2621    
2622    8. Added support for the \Q...\E escape sequence. Characters in between are
2623    treated as literals. This is slightly different from Perl in that $ and @ are
2624    also handled as literals inside the quotes. In Perl, they will cause variable
2625    interpolation. Note the following examples:
2626    
2627        Pattern            PCRE matches      Perl matches
2628    
2629        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2630        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2631        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2632    
2633    For compatibility with Perl, \Q...\E sequences are recognized inside character
2634    classes as well as outside them.
2635    
2636    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2637    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2638    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2639    signed/unsigned warnings.
2640    
2641    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2642    option for pcretest, so I've replaced it by a simple function that does just
2643    that job.
2644    
2645    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2646    "pcregrep -".
2647    
2648    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2649    Java package. This provides some syntactic sugar for simple cases of what my
2650    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2651    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2652    item, you can use this simplified notation. Note that only makes sense with
2653    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2654    greediness, whatever the setting of the PCRE_UNGREEDY option.
2655    
2656    13. A change of greediness default within a pattern was not taking effect at
2657    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2658    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2659    was abstracted outside.
2660    
2661    14. PCRE now supports the \G assertion. It is true when the current matching
2662    position is at the start point of the match. This differs from \A when the
2663    starting offset is non-zero. Used with the /g option of pcretest (or similar
2664    code), it works in the same way as it does for Perl's /g option. If all
2665    alternatives of a regex begin with \G, the expression is anchored to the start
2666    match position, and the "anchored" flag is set in the compiled expression.
2667    
2668    15. Some bugs concerning the handling of certain option changes within patterns
2669    have been fixed. These applied to options other than (?ims). For example,
2670    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2671    been the other way round. Some of this was related to change 7 above.
2672    
2673    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2674    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2675    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2676    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2677    
2678    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2679    mode. Unlike ".", it always matches newline, whatever the setting of
2680    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2681    assertions. Perl allows it, but it doesn't (in general) work because it can't
2682    calculate the length of the lookbehind. At least, that's the case for Perl
2683    5.8.0 - I've been told they are going to document that it doesn't work in
2684    future.
2685    
2686    18. Added an error diagnosis for escapes that PCRE does not support: these are
2687    \L, \l, \N, \P, \p, \U, \u, and \X.
2688    
2689    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2690    reading past the end of the pattern in cases such as /[abcd/.
2691    
2692    20. PCRE was getting more memory than necessary for patterns with classes that
2693    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2694    
2695    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2696    compiling PCRE for use with Virtual Pascal.
2697    
2698    22. Small fix to the Makefile to make it work properly if the build is done
2699    outside the source tree.
2700    
2701    23. Added a new extension: a condition to go with recursion. If a conditional
2702    subpattern starts with (?(R) the "true" branch is used if recursion has
2703    happened, whereas the "false" branch is used only at the top level.
2704    
2705    24. When there was a very long string of literal characters (over 255 bytes
2706    without UTF support, over 250 bytes with UTF support), the computation of how
2707    much memory was required could be incorrect, leading to segfaults or other
2708    strange effects.
2709    
2710    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2711    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2712    there was a subsequent back reference to those brackets. This meant that, for
2713    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2714    possible to check for precisely this case. All we can do is abandon the
2715    optimization if .* occurs inside capturing brackets when there are any back
2716    references whatsoever. (See below for a better fix that came later.)
2717    
2718    26. The handling of the optimization for finding the first character of a
2719    non-anchored pattern, and for finding a character that is required later in the
2720    match were failing in some cases. This didn't break the matching; it just
2721    failed to optimize when it could. The way this is done has been re-implemented.
2722    
2723    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2724    
2725    28. Added a new feature that provides some of the functionality that Perl
2726    provides with (?{...}). The facility is termed a "callout". The way it is done
2727    in PCRE is for the caller to provide an optional function, by setting
2728    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2729    global variable. By default it is unset, which disables all calling out. To get
2730    the function called, the regex must include (?C) at appropriate points. This
2731    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2732    This provides a means of identifying different callout points. When PCRE
2733    reaches such a point in the regex, if pcre_callout has been set, the external
2734    function is called. It is provided with data in a structure called
2735    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2736    matching continues; if it returns a non-zero value, the match at the current
2737    point fails. However, backtracking will occur if possible. [This was changed
2738    later and other features added - see item 49 below.]
2739    
2740    29. pcretest is upgraded to test the callout functionality. It provides a
2741    callout function that displays information. By default, it shows the start of
2742    the match and the current position in the text. There are some new data escapes
2743    to vary what happens:
2744    
2745        \C+         in addition, show current contents of captured substrings
2746        \C-         do not supply a callout function
2747        \C!n        return 1 when callout number n is reached
2748        \C!n!m      return 1 when callout number n is reached for the mth time
2749    
2750    30. If pcregrep was called with the -l option and just a single file name, it
2751    output "<stdin>" if a match was found, instead of the file name.
2752    
2753    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2754    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2755    pcre_exec(). This saves a malloc/free per call. The default value of
2756    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2757    when configuring.
2758    
2759    32. The default maximum size of a compiled pattern is 64K. There have been a
2760    few cases of people hitting this limit. The code now uses macros to handle the
2761    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2762    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2763    configuring. Tests 2 and 5 work only with 2-byte links because they output
2764    debugging information about compiled patterns.
2765    
2766    33. Internal code re-arrangements:
2767    
2768    (a) Moved the debugging function for printing out a compiled regex into
2769        its own source file (printint.c) and used #include to pull it into
2770        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2771        separate copies.
2772    
2773    (b) Defined the list of op-code names for debugging as a macro in
2774        internal.h so that it is next to the definition of the opcodes.
2775    
2776    (c) Defined a table of op-code lengths for simpler skipping along compiled
2777        code. This is again a macro in internal.h so that it is next to the
2778        definition of the opcodes.
2779    
2780    34. Added support for recursive calls to individual subpatterns, along the
2781    lines of Robin Houston's patch (but implemented somewhat differently).
2782    
2783    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2784    allow it to read and process whole directories in Win32. This code was
2785    contributed by Lionel Fourquaux; it has not been tested by me.
2786    
2787    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2788    used to name a group. Names consist of alphanumerics and underscores, and must
2789    be unique. Back references use the syntax (?P=name) and recursive calls use
2790    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2791    numbers. The function pcre_fullinfo() can be used after compilation to extract
2792    a name/number map. There are three relevant calls:
2793    
2794      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2795      PCRE_INFO_NAMECOUNT            yields the number of entries
2796      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2797    
2798    The map is a vector of fixed-size entries. The size of each entry depends on
2799    the length of the longest name used. The first two bytes of each entry are the
2800    group number, most significant byte first. There follows the corresponding
2801    name, zero terminated. The names are in alphabetical order.
2802    
2803    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2804    case instead of 255. Making it the same both with and without UTF-8 support
2805    means that the same test output works with both.
2806    
2807    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2808    calling malloc() with a zero argument.
2809    
2810    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2811    optimization. I've improved things by keeping a bitmap of backreferences with
2812    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2813    fact referenced, the optimization can be applied. It is unlikely that a
2814    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2815    the match to follow \n) will appear inside brackets with a number greater than
2816    31, but if it does, any back reference > 31 suppresses the optimization.
2817    
2818    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2819    of disabling numbered capturing parentheses. Any opening parenthesis that is
2820    not followed by ? behaves as if it were followed by ?: but named parentheses
2821    can still be used for capturing (and they will acquire numbers in the usual
2822    way).
2823    
2824    41. Redesigned the return codes from the match() function into yes/no/error so
2825    that errors can be passed back from deep inside the nested calls. A malloc
2826    failure while inside a recursive subpattern call now causes the
2827    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2828    
2829    42. It is now possible to set a limit on the number of times the match()
2830    function is called in a call to pcre_exec(). This facility makes it possible to
2831    limit the amount of recursion and backtracking, though not in a directly
2832    obvious way, because the match() function is used in a number of different
2833    circumstances. The count starts from zero for each position in the subject
2834    string (for non-anchored patterns). The default limit is, for compatibility, a
2835    large number, namely 10 000 000. You can change this in two ways:
2836    
2837    (a) When configuring PCRE before making, you can use --with-match-limit=n
2838        to set a default value for the compiled library.
2839    
2840    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2841        a different value is set. See 45 below.
2842    
2843    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2844    
2845    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2846    of things that can be changed at compile time. The first argument specifies
2847    what is wanted and the second points to where the information is to be placed.
2848    The current list of available information is:
2849    
2850      PCRE_CONFIG_UTF8
2851    
2852    The output is an integer that is set to one if UTF-8 support is available;
2853    otherwise it is set to zero.
2854    
2855      PCRE_CONFIG_NEWLINE
2856    
2857    The output is an integer that it set to the value of the code that is used for
2858    newline. It is either LF (10) or CR (13).
2859    
2860      PCRE_CONFIG_LINK_SIZE
2861    
2862    The output is an integer that contains the number of bytes used for internal
2863    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2864    
2865      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2866    
2867    The output is an integer that contains the threshold above which the POSIX
2868    interface uses malloc() for output vectors. See item 31 above.
2869    
2870      PCRE_CONFIG_MATCH_LIMIT
2871    
2872    The output is an unsigned integer that contains the default limit of the number
2873    of match() calls in a pcre_exec() execution. See 42 above.
2874    
2875    44. pcretest has been upgraded by the addition of the -C option. This causes it
2876    to extract all the available output from the new pcre_config() function, and to
2877    output it. The program then exits immediately.
2878    
2879    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2880    order to support additional features. One way would have been to define
2881    pcre_exec2() (for example) with extra arguments, but this would not have been
2882    extensible, and would also have required all calls to the original function to
2883    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2884    is used for passing in "extra" data from pcre_study().
2885    
2886    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2887    contains the following fields:
2888    
2889      flags         a bitmap indicating which of the following fields are set
2890      study_data    opaque data from pcre_study()
2891      match_limit   a way of specifying a limit on match() calls for a specific
2892                      call to pcre_exec()
2893      callout_data  data for callouts (see 49 below)
2894    
2895    The flag bits are also defined in pcre.h, and are
2896    
2897      PCRE_EXTRA_STUDY_DATA
2898      PCRE_EXTRA_MATCH_LIMIT
2899      PCRE_EXTRA_CALLOUT_DATA
2900    
2901    The pcre_study() function now returns one of these new pcre_extra blocks, with
2902    the actual study data pointed to by the study_data field, and the
2903    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2904    before. That is, this change is entirely upwards-compatible and requires no
2905    change to existing code.
2906    
2907    If you want to pass in additional data to pcre_exec(), you can either place it
2908    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2909    block.
2910    
2911    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2912    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2913    times with different match limits, until it finds the minimum value needed for
2914    pcre_exec() to complete. The value is then output. This can be instructive; for
2915    most simple matches the number is quite small, but for pathological cases it
2916    gets very large very quickly.
2917    
2918    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2919    returns the size of the data block pointed to by the study_data field in a
2920    pcre_extra block, that is, the value that was passed as the argument to
2921    pcre_malloc() when PCRE was getting memory in which to place the information
2922    created by pcre_study(). The fourth argument should point to a size_t variable.
2923    pcretest has been extended so that this information is shown after a successful
2924    pcre_study() call when information about the compiled regex is being displayed.
2925    
2926    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2927    because what follows is always an absolute path. (Later: it turns out that this
2928    is more than cosmetic for MinGW, because it doesn't like empty path
2929    components.)
2930    
2931    49. Some changes have been made to the callout feature (see 28 above):
2932    
2933    (i)  A callout function now has three choices for what it returns:
2934    
2935           0  =>  success, carry on matching
2936         > 0  =>  failure at this point, but backtrack if possible
2937         < 0  =>  serious error, return this value from pcre_exec()
2938    
2939         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2940         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2941         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2942         use by callout functions. It will never be used by PCRE itself.
2943    
2944    (ii) The pcre_extra structure (see 45 above) has a void * field called
2945         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2946         pcre_callout_block structure has a field of the same name. The contents of
2947         the field passed in the pcre_extra structure are passed to the callout
2948         function in the corresponding field in the callout block. This makes it
2949         easier to use the same callout-containing regex from multiple threads. For
2950         testing, the pcretest program has a new data escape
2951    
2952           \C*n        pass the number n (may be negative) as callout_data
2953    
2954         If the callout function in pcretest receives a non-zero value as
2955         callout_data, it returns that value.
2956    
2957    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2958    there were some redundant $(CFLAGS) in commands that are now specified as
2959    $(LINK), which already includes $(CFLAGS).
2960    
2961    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2962    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2963    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2964    one-byte characters throughout. Note that case-insensitive matching applies
2965    only to characters whose values are less than 256. PCRE doesn't support the
2966    notion of cases for higher-valued characters.
2967    
2968    (i)   A character class whose characters are all within 0-255 is handled as
2969          a bit map, and the map is inverted for negative classes. Previously, a
2970          character > 255 always failed to match such a class; however it should
2971          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2972    
2973    (ii)  A negated character class with a single character < 255 is coded as
2974          "not this character" (OP_NOT). This wasn't working properly when the test
2975          character was multibyte, either singly or repeated.
2976    
2977    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2978          mode, for example: \x{100}{2,3}.
2979    
2980    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2981          singly or repeated) now correctly test multibyte characters. However,
2982          PCRE doesn't recognize any characters with values greater than 255 as
2983          digits, spaces, or word characters. Such characters always match \D, \S,
2984          and \W, and never match \d, \s, or \w.
2985    
2986    (v)   Classes may now contain characters and character ranges with values
2987          greater than 255. For example: [ab\x{100}-\x{400}].
2988    
2989    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2990          PCRE in UTF-8 mode.
2991    
2992    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2993    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2994    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2995    value.)
2996    
2997    53. The single man page has become too large. I have therefore split it up into
2998    a number of separate man pages. These also give rise to individual HTML pages;
2999    these are now put in a separate directory, and there is an index.html page that
3000    lists them all. Some hyperlinking between the pages has been installed.
3001    
3002    54. Added convenience functions for handling named capturing parentheses.
3003    
3004    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3005    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3006    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3007    are faulted.
3008    
3009    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3010    calling configure. These values are used when compiling the dftables.c program
3011    which is run to generate the source of the default character tables. They
3012    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3013    you will need to set these values.
3014    
3015    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3016    
3017    
3018    Version 3.9 02-Jan-02
3019    ---------------------
3020    
3021    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3022    
3023    2. If --disable-static was given, the building process failed when trying to
3024    build pcretest and pcregrep. (For some reason it was using libtool to compile
3025    them, which is not right, as they aren't part of the library.)
3026    
3027    
3028    Version 3.8 18-Dec-01
3029    ---------------------
3030    
3031    1. The experimental UTF-8 code was completely screwed up. It was packing the
3032    bytes in the wrong order. How dumb can you get?
3033    
3034    
3035    Version 3.7 29-Oct-01
3036    ---------------------
3037    
3038    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3039    This caused pcretest, when used on the test data, to segfault. Unfortunately,
3040    this didn't happen under Solaris 8, where I normally test things.
3041    
3042    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3043    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3044    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3045    this fix an hour or so after the initial 3.7 release.)
3046    
3047    
3048    Version 3.6 23-Oct-01
3049    ---------------------
3050    
3051    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3052    offsets passed as NULL with zero offset count.
3053    
3054    2. The config.guess and config.sub files had not been updated when I moved to
3055    the latest autoconf.
3056    
3057    
3058    Version 3.5 15-Aug-01
3059    ---------------------
3060    
3061    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3062    had been forgotten.
3063    
3064    2. By using declared but undefined structures, we can avoid using "void"
3065    definitions in pcre.h while keeping the internal definitions of the structures
3066    private.
3067    
3068    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3069    user point of view, this means that both static and shared libraries are built
3070    by default, but this can be individually controlled. More of the work of
3071    handling this static/shared cases is now inside libtool instead of PCRE's make
3072    file.
3073    
3074    4. The pcretest utility is now installed along with pcregrep because it is
3075    useful for users (to test regexs) and by doing this, it automatically gets
3076    relinked by libtool. The documentation has been turned into a man page, so
3077    there are now .1, .txt, and .html versions in /doc.
3078    
3079    5. Upgrades to pcregrep:
3080       (i)   Added long-form option names like gnu grep.
3081       (ii)  Added --help to list all options with an explanatory phrase.
3082       (iii) Added -r, --recursive to recurse into sub-directories.
3083       (iv)  Added -f, --file to read patterns from a file.
3084    
3085    6. pcre_exec() was referring to its "code" argument before testing that
3086    argument for NULL (and giving an error if it was NULL).
3087    
3088    7. Upgraded Makefile.in to allow for compiling in a different directory from
3089    the source directory.
3090    
3091    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3092    options bits, the pointer it was passed was to an int instead of to an unsigned
3093    long int. This mattered only on 64-bit systems.
3094    
3095    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3096    generated) instead of pcre.in, which it its source. Also made the same change
3097    in several of the .c files.
3098    
3099    10. A new release of gcc defines printf() as a macro, which broke pcretest
3100    because it had an ifdef in the middle of a string argument for printf(). Fixed
3101    by using separate calls to printf().
3102    
3103    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3104    script, to force use of CR or LF instead of \n in the source. On non-Unix
3105    systems, the value can be set in config.h.
3106    
3107    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3108    absolute limit. Changed the text of the error message to make this clear, and
3109    likewise updated the man page.
3110    
3111    13. The limit of 99 on the number of capturing subpatterns has been removed.
3112    The new limit is 65535, which I hope will not be a "real" limit.
3113    
3114    
3115    Version 3.4 22-Aug-00
3116    ---------------------
3117    
3118    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3119    
3120    2. Diagnose condition (?(0) as an error instead of crashing on matching.
3121    
3122    
3123    Version 3.3 01-Aug-00
3124    ---------------------
3125    
3126    1. If an octal character was given, but the value was greater than \377, it
3127    was not getting masked to the least significant bits, as documented. This could
3128    lead to crashes in some systems.
3129    
3130    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3131    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3132    
3133    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3134    These just pass their arguments on to (pcre_free)(), but they are provided
3135    because some uses of PCRE bind it to non-C systems that can call its functions,
3136    but cannot call free() or pcre_free() directly.
3137    
3138    4. Add "make test" as a synonym for "make check". Corrected some comments in
3139    the Makefile.
3140    
3141    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3142    Makefile.
3143    
3144    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3145    command called pgrep for grepping around the active processes.
3146    
3147    7. Added the beginnings of support for UTF-8 character strings.
3148    
3149    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3150    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3151    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3152    out for the ar command.)
3153    
3154    
3155    Version 3.2 12-May-00
3156    ---------------------
3157    
3158    This is purely a bug fixing release.
3159    
3160    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3161    of ZA. This was just one example of several cases that could provoke this bug,
3162    which was introduced by change 9 of version 2.00. The code for breaking
3163    infinite loops after an iteration that matches an empty string was't working
3164    correctly.
3165    
3166    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3167    when matched against abbab (for example). After matching an empty string, it
3168    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3169    caused it to match further down the string than it should.
3170    
3171    3. The code contained an inclusion of sys/types.h. It isn't clear why this
3172    was there because it doesn't seem to be needed, and it causes trouble on some
3173    systems, as it is not a Standard C header. It has been removed.
3174    
3175    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3176    were reported on the Macintosh. The changes were from
3177    
3178      while ((c = *(++ptr)) != 0 && c != '\n');
3179    to
3180      while ((c = *(++ptr)) != 0 && c != '\n') ;
3181    
3182    Totally extraordinary, but if that's what it takes...
3183    
3184    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3185    available. Added HAVE_BCOPY and an autoconf test for it; if neither
3186    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3187    assumes the way PCRE uses memmove() (always moving upwards).
3188    
3189    6. PCRE is being used in one environment where strchr() is not available. There
3190    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3191    faster code anyway.
3192    
3193    
3194    Version 3.1 09-Feb-00
3195    ---------------------
3196    
3197    The only change in this release is the fixing of some bugs in Makefile.in for
3198    the "install" target:
3199    
3200    (1) It was failing to install pcreposix.h.
3201    
3202    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3203    
3204    
3205    Version 3.0 01-Feb-00
3206    ---------------------
3207    
3208    1. Add support for the /+ modifier to perltest (to output $` like it does in
3209    pcretest).
3210    
3211    2. Add support for the /g modifier to perltest.
3212    
3213    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3214    matches null strings.
3215    
3216    4. Fix perltest so that it doesn't do unwanted things when fed an empty
3217    pattern. Perl treats empty patterns specially - it reuses the most recent
3218    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3219    effect.
3220    
3221    5. The POSIX interface was broken in that it was just handing over the POSIX
3222    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3223    required a bigger vector, with some working space on the end. This means that
3224    the POSIX wrapper now has to get and free some memory, and copy the results.
3225    
3226    6. Added some simple autoconf support, placing the test data and the
3227    documentation in separate directories, re-organizing some of the
3228    information files, and making it build pcre-config (a GNU standard). Also added
3229    libtool support for building PCRE as a shared library, which is now the
3230    default.
3231    
3232    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3233    09 are not valid octal constants. Single digits will be used for minor values
3234    less than 10.
3235    
3236    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3237    existing programs that set these in the POSIX interface can use PCRE without
3238    modification.
3239    
3240    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3241    return all that pcre_info() returns, plus additional data. The pcre_info()
3242    function is retained for compatibility, but is considered to be obsolete.
3243    
3244    10. Added experimental recursion feature (?R) to handle one common case that
3245    Perl 5.6 will be able to do with (?p{...}).
3246    
3247    11. Added support for POSIX character classes like [:alpha:], which Perl is
3248    adopting.
3249    
3250    
3251    Version 2.08 31-Aug-99
3252    ----------------------
3253    
3254    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3255    trying to match at the startoffset position, but instead was moving forward to
3256    the next newline as if a previous match had failed.
3257    
3258    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3259    and could get into a loop if a null string was matched other than at the start
3260    of the subject.
3261    
3262    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3263    be distinguished at compile time, and for completeness also added PCRE_DATE.
3264    
3265    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3266    in GnuWin32 environments.
3267    
3268    
3269    Version 2.07 29-Jul-99
3270    ----------------------
3271    
3272    1. The documentation is now supplied in plain text form and HTML as well as in
3273    the form of man page sources.
3274    
3275    2. C++ compilers don't like assigning (void *) values to other pointer types.
3276    In particular this affects malloc(). Although there is no problem in Standard
3277    C, I've put in casts to keep C++ compilers happy.
3278    
3279    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3280    should be (const char *).
3281    
3282    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3283    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3284    However, I haven't made this a standard facility. The documentation doesn't
3285    mention it, and the Makefile doesn't support it.
3286    
3287    5. The Makefile now contains an "install" target, with editable destinations at
3288    the top of the file. The pcretest program is not installed.
3289    
3290    6. pgrep -V now gives the PCRE version number and date.
3291    
3292    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3293    causing the entire string to be ignored, instead of just the last character.
3294    
3295    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3296    non-matching string, it can take a very, very long time, even for strings of
3297    quite modest length, because of the nested recursion. PCRE now does better in
3298    some of these cases. It does this by remembering the last required literal
3299    character in the pattern, and pre-searching the subject to ensure it is present
3300    before running the real match. In other words, it applies a heuristic to detect
3301    some types of certain failure quickly, and in the above example, if presented
3302    with a string that has no trailing " it gives "no match" very quickly.
3303    
3304    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3305    other alternatives are tried instead.
3306    
3307    
3308  Version 2.06 09-Jun-99  Version 2.06 09-Jun-99
3309  ----------------------  ----------------------

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