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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.10 03 May-2010
5    ------------------------
6    
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
9    
10    2.  (*ACCEPT) was not working when inside an atomic group.
11    
12    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
15    
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
19    
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
22    
23    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
28    
29    7.  Minor change to pcretest.c to avoid a compiler warning.
30    
31    8.  Added four artifical Unicode properties to help with an option to make
32        \s etc use properties (see next item). The new properties are: Xan
33        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
34    
35    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
36        use Unicode properties. (*UCP) at the start of a pattern can be used to set
37        this option. Modified pcretest to add /W to test this facility. Added
38        REG_UCP to make it available via the POSIX interface.
39    
40    10. Added --line-buffered to pcregrep.
41    
42    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
43        studied, and the match started with a letter with a code point greater than
44        127 whose first byte was different to the first byte of the other case of
45        the letter, the other case of this starting letter was not recognized.
46    
47    12. pcreposix.c included pcre.h before including pcre_internal.h. This caused a
48        conflict in the definition of PCRE_EXP_DECL. I have removed the include of
49        pcre.h as pcre_internal.h includes pcre.h itself. (This may be a bit of
50        historical tidying that never got done.)
51    
52    13. If a pattern that was studied started with a repeated Unicode property
53        test, for example, \p{Nd}+, there was the theoretical possibility of
54        setting up an incorrect bitmap of starting bytes, but fortunately it could
55        not have actually happened in practice until change 8 above was made (it
56        added property types that matched character-matching opcodes).
57    
58    14. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
59        possible starting bytes for non-anchored patterns.
60    
61    15. The "auto-possessify" feature of pcre_compile() now recognizes \R.
62    
63    16. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
64        input, it could crash or give wrong results if characters with values
65        greater than 0xc0 were present in the subject string. (Detail: it assumed
66        UTF-8 input when processing these items.)
67    
68    
69    
70    Version 8.02 19-Mar-2010
71    ------------------------
72    
73    1.  The Unicode data tables have been updated to Unicode 5.2.0.
74    
75    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
76        configured.
77    
78    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
79        original author of that file, following a query about its status.
80    
81    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
82        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
83    
84    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
85        quantifier applied to a forward-referencing subroutine call, could compile
86        incorrect code or give the error "internal error: previously-checked
87        referenced subpattern not found".
88    
89    6.  Both MS Visual Studio and Symbian OS have problems with initializing
90        variables to point to external functions. For these systems, therefore,
91        pcre_malloc etc. are now initialized to local functions that call the
92        relevant global functions.
93    
94    7.  There were two entries missing in the vectors called coptable and poptable
95        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
96        I've fixed the data, and added a kludgy way of testing at compile time that
97        the lengths are correct (equal to the number of opcodes).
98    
99    8.  Following on from 7, I added a similar kludge to check the length of the
100        eint vector in pcreposix.c.
101    
102    9.  Error texts for pcre_compile() are held as one long string to avoid too
103        much relocation at load time. To find a text, the string is searched,
104        counting zeros. There was no check for running off the end of the string,
105        which could happen if a new error number was added without updating the
106        string.
107    
108    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
109    
110    11. \K was not working if it appeared in an atomic group or in a group that
111        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
112        \K is "not well defined" if used in an assertion. PCRE now accepts it if
113        the assertion is positive, but not if it is negative.
114    
115    12. Change 11 fortuitously reduced the size of the stack frame used in the
116        "match()" function of pcre_exec.c by one pointer. Forthcoming
117        implementation of support for (*MARK) will need an extra pointer on the
118        stack; I have reserved it now, so that the stack frame size does not
119        decrease.
120    
121    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
122        item in branch that calls a recursion is a subroutine call - as in the
123        second branch in the above example - was incorrectly given the compile-
124        time error "recursive call could loop indefinitely" because pcre_compile()
125        was not correctly checking the subroutine for matching a non-empty string.
126    
127    14. The checks for overrunning compiling workspace could trigger after an
128        overrun had occurred. This is a "should never occur" error, but it can be
129        triggered by pathological patterns such as hundreds of nested parentheses.
130        The checks now trigger 100 bytes before the end of the workspace.
131    
132    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
133    
134    
135    Version 8.01 19-Jan-2010
136    ------------------------
137    
138    1.  If a pattern contained a conditional subpattern with only one branch (in
139        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
140        computed the wrong minimum data length (which is of course zero for such
141        subpatterns). This could cause incorrect "no match" results.
142    
143    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
144        the pattern is reset in the first branch, pcre_compile() failed with
145        "internal error: code overflow at offset...". This happened only when
146        the reset was to the original external option setting. (An optimization
147        abstracts leading options settings into an external setting, which was the
148        cause of this.)
149    
150    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
151        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
152        assertion pattern did not match (meaning that the assertion was true), it
153        was incorrectly treated as false if the SKIP had been reached during the
154        matching. This also applied to assertions used as conditions.
155    
156    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
157        assertion subpattern, including such a pattern used as a condition,
158        unpredictable results occurred, instead of the error return
159        PCRE_ERROR_DFA_UITEM.
160    
161    5.  The C++ GlobalReplace function was not working like Perl for the special
162        situation when an empty string is matched. It now does the fancy magic
163        stuff that is necessary.
164    
165    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
166        removed. (These were left over from very, very early versions of PCRE.)
167    
168    7.  Some cosmetic changes to the code to make life easier when compiling it
169        as part of something else:
170    
171        (a) Change DEBUG to PCRE_DEBUG.
172    
173        (b) In pcre_compile(), rename the member of the "branch_chain" structure
174            called "current" as "current_branch", to prevent a collision with the
175            Linux macro when compiled as a kernel module.
176    
177        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
178            prevent a collision with the Linux macro when compiled as a kernel
179            module.
180    
181    8.  In pcre_compile() there are some checks for integer overflows that used to
182        cast potentially large values to (double). This has been changed to that
183        when building, a check for int64_t is made, and if it is found, it is used
184        instead, thus avoiding the use of floating point arithmetic. (There is no
185        other use of FP in PCRE.) If int64_t is not found, the fallback is to
186        double.
187    
188    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
189        2005 (difference between two addresses compared to an unsigned value).
190    
191    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
192        custom one, because of the following reported problem in Windows:
193    
194          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
195              under Win32.
196          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
197              therefore missing the function definition.
198          - The compiler thus generates a "C" signature for the test function.
199          - The linker fails to find the "C" function.
200          - PCRE fails to configure if asked to do so against libbz2.
201    
202    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
203        messages were output:
204    
205          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
206          rerunning libtoolize, to keep the correct libtool macros in-tree.
207          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
208    
209        I have done both of these things.
210    
211    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
212        most of the time, it *can* run out if it is given a pattern that contains a
213        runaway infinite recursion. I updated the discussion in the pcrestack man
214        page.
215    
216    13. Now that we have gone to the x.xx style of version numbers, the minor
217        version may start with zero. Using 08 or 09 is a bad idea because users
218        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
219        interpreted as invalid octal numbers. I've updated the previous comment in
220        configure.ac, and also added a check that gives an error if 08 or 09 are
221        used.
222    
223    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
224        causing partial matching to fail when the end of the subject matched \W
225        in a UTF-8 pattern where \W was quantified with a minimum of 3.
226    
227    15. There were some discrepancies between the declarations in pcre_internal.h
228        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
229        their definitions. The declarations used "const uschar *" and the
230        definitions used USPTR. Even though USPTR is normally defined as "const
231        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
232        reported that: "This difference in casting confuses some C++ compilers, for
233        example, SunCC recognizes above declarations as different functions and
234        generates broken code for hbpcre." I have changed the declarations to use
235        USPTR.
236    
237    16. GNU libtool is named differently on some systems. The autogen.sh script now
238        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
239        (FreeBSD).
240    
241    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
242        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
243        comment: "Figure out how to create a longlong from a string: strtoll and
244        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
245        instance, but it only takes 2 args instead of 3!"
246    
247    18. A subtle bug concerned with back references has been fixed by a change of
248        specification, with a corresponding code fix. A pattern such as
249        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
250        refers, was giving matches when it shouldn't. For example, xa=xaaa would
251        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
252        same bug. Such groups have to be quantified to be useful, or contained
253        inside another quantified group. (If there's no repetition, the reference
254        can never match.) The problem arises because, having left the group and
255        moved on to the rest of the pattern, a later failure that backtracks into
256        the group uses the captured value from the final iteration of the group
257        rather than the correct earlier one. I have fixed this in PCRE by forcing
258        any group that contains a reference to itself to be an atomic group; that
259        is, there cannot be any backtracking into it once it has completed. This is
260        similar to recursive and subroutine calls.
261    
262    
263    Version 8.00 19-Oct-09
264    ----------------------
265    
266    1.  The table for translating pcre_compile() error codes into POSIX error codes
267        was out-of-date, and there was no check on the pcre_compile() error code
268        being within the table. This could lead to an OK return being given in
269        error.
270    
271    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
272        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
273        in a Windows environment.
274    
275    3.  The pcregrep --count option prints the count for each file even when it is
276        zero, as does GNU grep. However, pcregrep was also printing all files when
277        --files-with-matches was added. Now, when both options are given, it prints
278        counts only for those files that have at least one match. (GNU grep just
279        prints the file name in this circumstance, but including the count seems
280        more useful - otherwise, why use --count?) Also ensured that the
281        combination -clh just lists non-zero counts, with no names.
282    
283    4.  The long form of the pcregrep -F option was incorrectly implemented as
284        --fixed_strings instead of --fixed-strings. This is an incompatible change,
285        but it seems right to fix it, and I didn't think it was worth preserving
286        the old behaviour.
287    
288    5.  The command line items --regex=pattern and --regexp=pattern were not
289        recognized by pcregrep, which required --regex pattern or --regexp pattern
290        (with a space rather than an '='). The man page documented the '=' forms,
291        which are compatible with GNU grep; these now work.
292    
293    6.  No libpcreposix.pc file was created for pkg-config; there was just
294        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
295    
296    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
297        when UCP support is not needed, by modifying the Python script that
298        generates it from Unicode data files. This should not matter if the module
299        is correctly used as a library, but I received one complaint about 50K of
300        unwanted data. My guess is that the person linked everything into his
301        program rather than using a library. Anyway, it does no harm.
302    
303    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
304        was a minimum greater than 1 for a wide character in a possessive
305        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
306        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
307        character. Chaos in the form of incorrect output or a compiling loop could
308        result.
309    
310    9.  The restrictions on what a pattern can contain when partial matching is
311        requested for pcre_exec() have been removed. All patterns can now be
312        partially matched by this function. In addition, if there are at least two
313        slots in the offset vector, the offset of the earliest inspected character
314        for the match and the offset of the end of the subject are set in them when
315        PCRE_ERROR_PARTIAL is returned.
316    
317    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
318        synonymous with PCRE_PARTIAL, for backwards compatibility, and
319        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
320        and may be more useful for multi-segment matching.
321    
322    11. Partial matching with pcre_exec() is now more intuitive. A partial match
323        used to be given if ever the end of the subject was reached; now it is
324        given only if matching could not proceed because another character was
325        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
326        string "Z", which now yields "no match" instead of "partial match". In the
327        case of pcre_dfa_exec(), "no match" is given if every matching path for the
328        final character ended with (*FAIL).
329    
330    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
331        if the pattern had a "must contain" character that was already found in the
332        earlier partial match, unless partial matching was again requested. For
333        example, with the pattern /dog.(body)?/, the "must contain" character is
334        "g". If the first part-match was for the string "dog", restarting with
335        "sbody" failed. This bug has been fixed.
336    
337    13. The string returned by pcre_dfa_exec() after a partial match has been
338        changed so that it starts at the first inspected character rather than the
339        first character of the match. This makes a difference only if the pattern
340        starts with a lookbehind assertion or \b or \B (\K is not supported by
341        pcre_dfa_exec()). It's an incompatible change, but it makes the two
342        matching functions compatible, and I think it's the right thing to do.
343    
344    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
345        so that the demonstration program is easily available in environments where
346        PCRE has not been installed from source.
347    
348    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
349        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
350        library.
351    
352    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
353        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
354        is not the first non-POSIX option to be added. Clearly some people find
355        these options useful.
356    
357    17. If a caller to the POSIX matching function regexec() passes a non-zero
358        value for nmatch with a NULL value for pmatch, the value of
359        nmatch is forced to zero.
360    
361    18. RunGrepTest did not have a test for the availability of the -u option of
362        the diff command, as RunTest does. It now checks in the same way as
363        RunTest, and also checks for the -b option.
364    
365    19. If an odd number of negated classes containing just a single character
366        interposed, within parentheses, between a forward reference to a named
367        subpattern and the definition of the subpattern, compilation crashed with
368        an internal error, complaining that it could not find the referenced
369        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
370        [The bug was that it was starting one character too far in when skipping
371        over the character class, thus treating the ] as data rather than
372        terminating the class. This meant it could skip too much.]
373    
374    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
375        /g option in pcretest when the pattern contains \K, which makes it possible
376        to have an empty string match not at the start, even when the pattern is
377        anchored. Updated pcretest and pcredemo to use this option.
378    
379    21. If the maximum number of capturing subpatterns in a recursion was greater
380        than the maximum at the outer level, the higher number was returned, but
381        with unset values at the outer level. The correct (outer level) value is
382        now given.
383    
384    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
385        PCRE did not set those parentheses (unlike Perl). I have now found a way to
386        make it do so. The string so far is captured, making this feature
387        compatible with Perl.
388    
389    23. The tests have been re-organized, adding tests 11 and 12, to make it
390        possible to check the Perl 5.10 features against Perl 5.10.
391    
392    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
393        pattern matches a fixed length string. PCRE did not allow this; now it
394        does. Neither allows recursion.
395    
396    25. I finally figured out how to implement a request to provide the minimum
397        length of subject string that was needed in order to match a given pattern.
398        (It was back references and recursion that I had previously got hung up
399        on.) This code has now been added to pcre_study(); it finds a lower bound
400        to the length of subject needed. It is not necessarily the greatest lower
401        bound, but using it to avoid searching strings that are too short does give
402        some useful speed-ups. The value is available to calling programs via
403        pcre_fullinfo().
404    
405    26. While implementing 25, I discovered to my embarrassment that pcretest had
406        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
407        study optimizations had never been tested with that matching function.
408        Oops. What is worse, even when it was passed study data, there was a bug in
409        pcre_dfa_exec() that meant it never actually used it. Double oops. There
410        were also very few tests of studied patterns with pcre_dfa_exec().
411    
412    27. If (?| is used to create subpatterns with duplicate numbers, they are now
413        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
414        on the other side of the coin, they are no longer allowed to have different
415        names, because these cannot be distinguished in PCRE, and this has caused
416        confusion. (This is a difference from Perl.)
417    
418    28. When duplicate subpattern names are present (necessarily with different
419        numbers, as required by 27 above), and a test is made by name in a
420        conditional pattern, either for a subpattern having been matched, or for
421        recursion in such a pattern, all the associated numbered subpatterns are
422        tested, and the overall condition is true if the condition is true for any
423        one of them. This is the way Perl works, and is also more like the way
424        testing by number works.
425    
426    
427    Version 7.9 11-Apr-09
428    ---------------------
429    
430    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
431        (pcretest), all targets were linked against these libraries. This included
432        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
433        libraries. This caused unwanted dependencies to be created. This problem
434        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
435        pcretest is linked with readline.
436    
437    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
438        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
439        moved outside it again, because FALSE and TRUE are already defined in AIX,
440        but BOOL is not.
441    
442    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
443        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
444    
445    4.  The pcregrep documentation said spaces were inserted as well as colons (or
446        hyphens) following file names and line numbers when outputting matching
447        lines. This is not true; no spaces are inserted. I have also clarified the
448        wording for the --colour (or --color) option.
449    
450    5.  In pcregrep, when --colour was used with -o, the list of matching strings
451        was not coloured; this is different to GNU grep, so I have changed it to be
452        the same.
453    
454    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
455        each matching line was coloured. Now it goes on to look for further matches
456        of any of the test patterns, which is the same behaviour as GNU grep.
457    
458    7.  A pattern that could match an empty string could cause pcregrep to loop; it
459        doesn't make sense to accept an empty string match in pcregrep, so I have
460        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
461        seems to be how GNU grep behaves.
462    
463    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
464        start or after a newline", because the conditional assertion was not being
465        correctly handled. The rule now is that both the assertion and what follows
466        in the first alternative must satisfy the test.
467    
468    9.  If auto-callout was enabled in a pattern with a conditional group whose
469        condition was an assertion, PCRE could crash during matching, both with
470        pcre_exec() and pcre_dfa_exec().
471    
472    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
473        used for matching.
474    
475    11. Unicode property support in character classes was not working for
476        characters (bytes) greater than 127 when not in UTF-8 mode.
477    
478    12. Added the -M command line option to pcretest.
479    
480    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
481    
482    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
483    
484    16. Added comments and documentation about mis-use of no_arg in the C++
485        wrapper.
486    
487    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
488        from Martin Jerabek that uses macro names for all relevant character and
489        string constants.
490    
491    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
492        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
493        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
494        these, but not everybody uses configure.
495    
496    19. A conditional group that had only one branch was not being correctly
497        recognized as an item that could match an empty string. This meant that an
498        enclosing group might also not be so recognized, causing infinite looping
499        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
500        with the subject "ab", where knowledge that the repeated group can match
501        nothing is needed in order to break the loop.
502    
503    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
504        exec(), but without supplying a callout function, matching went wrong.
505    
506    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
507        leak if the size of the offset vector was greater than 30. When the vector
508        is smaller, the saved offsets during recursion go onto a local stack
509        vector, but for larger vectors malloc() is used. It was failing to free
510        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
511        error, in fact).
512    
513    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
514        heapframe that is used only when UTF-8 support is enabled. This caused no
515        problem, but was untidy.
516    
517    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
518        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
519        included within another project.
520    
521    24. Steven Van Ingelgem's patches to add more options to the CMake support,
522        slightly modified by me:
523    
524          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
525              not building pcregrep.
526    
527          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
528              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
529    
530    25. Forward references, both numeric and by name, in patterns that made use of
531        duplicate group numbers, could behave incorrectly or give incorrect errors,
532        because when scanning forward to find the reference group, PCRE was not
533        taking into account the duplicate group numbers. A pattern such as
534        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
535    
536    26. Changed a few more instances of "const unsigned char *" to USPTR, making
537        the feature of a custom pointer more persuasive (as requested by a user).
538    
539    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
540        pcretest.c, inside #ifndefs, because it seems they are sometimes already
541        pre-defined.
542    
543    28. Added support for (*UTF8) at the start of a pattern.
544    
545    29. Arrange for flags added by the "release type" setting in CMake to be shown
546        in the configuration summary.
547    
548    
549    Version 7.8 05-Sep-08
550    ---------------------
551    
552    1.  Replaced UCP searching code with optimized version as implemented for Ad
553        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
554        stage table and inline lookup instead of a function, giving speed ups of 2
555        to 5 times on some simple patterns that I tested. Permission was given to
556        distribute the MultiStage2.py script that generates the tables (it's not in
557        the tarball, but is in the Subversion repository).
558    
559    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
560        scripts.
561    
562    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
563        a group with a zero qualifier. The result of the study could be incorrect,
564        or the function might crash, depending on the pattern.
565    
566    4.  Caseless matching was not working for non-ASCII characters in back
567        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
568        It now works when Unicode Property Support is available.
569    
570    5.  In pcretest, an escape such as \x{de} in the data was always generating
571        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
572        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
573        truncation.
574    
575    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
576    
577    7.  Added two (int) casts to pcregrep when printing the difference of two
578        pointers, in case they are 64-bit values.
579    
580    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
581        test 2 if it fails.
582    
583    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
584        and a #define of that name to empty if it is not externally set. This is to
585        allow users of MSVC to set it if necessary.
586    
587    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
588        the convenience functions in the pcre_get.c source file.
589    
590    11. An option change at the start of a pattern that had top-level alternatives
591        could cause overwriting and/or a crash. This command provoked a crash in
592        some environments:
593    
594          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
595    
596        This potential security problem was recorded as CVE-2008-2371.
597    
598    12. For a pattern where the match had to start at the beginning or immediately
599        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
600        pcre_dfa_exec() could read past the end of the passed subject if there was
601        no match. To help with detecting such bugs (e.g. with valgrind), I modified
602        pcretest so that it places the subject at the end of its malloc-ed buffer.
603    
604    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
605        exec() might read past the end of the data buffer in UTF-8 mode.
606    
607    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
608        the data contained the byte 0x85 as part of a UTF-8 character within its
609        first line. This applied both to normal and DFA matching.
610    
611    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
612        /^[^d]*?$/8 failed to match "abc".
613    
614    16. Added a missing copyright notice to pcrecpp_internal.h.
615    
616    17. Make it more clear in the documentation that values returned from
617        pcre_exec() in ovector are byte offsets, not character counts.
618    
619    18. Tidied a few places to stop certain compilers from issuing warnings.
620    
621    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
622        supplied by Stefan Weber. I made a further small update for 7.8 because
623        there is a change of source arrangements: the pcre_searchfuncs.c module is
624        replaced by pcre_ucd.c.
625    
626    
627    Version 7.7 07-May-08
628    ---------------------
629    
630    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
631        a string to a long long, pretend we don't even have a long long." This is
632        done by checking for the strtoq, strtoll, and _strtoi64 functions.
633    
634    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
635        pre-7.6 versions, which defined a global no_arg variable instead of putting
636        it in the RE class. (See also #8 below.)
637    
638    3.  Remove a line of dead code, identified by coverity and reported by Nuno
639        Lopes.
640    
641    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
642    
643        (1) The include/exclude patterns were being applied to the whole pathnames
644            of files, instead of just to the final components.
645    
646        (2) If there was more than one level of directory, the subdirectories were
647            skipped unless they satisfied the include/exclude conditions. This is
648            inconsistent with GNU grep (and could even be seen as contrary to the
649            pcregrep specification - which I improved to make it absolutely clear).
650            The action now is always to scan all levels of directory, and just
651            apply the include/exclude patterns to regular files.
652    
653    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
654        --exclude_dir in the tests to avoid scanning .svn directories.
655    
656    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
657        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
658        doesn't support NULs in patterns.
659    
660    7.  Added some missing "const"s to declarations of static tables in
661        pcre_compile.c and pcre_dfa_exec.c.
662    
663    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
664        caused by fix #2  above. (Subsequently also a second patch to fix the
665        first patch. And a third patch - this was a messy problem.)
666    
667    9.  Applied Craig's patch to remove the use of push_back().
668    
669    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
670        matching function regexec().
671    
672    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
673        which, however, unlike Perl's \g{...}, are subroutine calls, not back
674        references. PCRE supports relative numbers with this syntax (I don't think
675        Oniguruma does).
676    
677    12. Previously, a group with a zero repeat such as (...){0} was completely
678        omitted from the compiled regex. However, this means that if the group
679        was called as a subroutine from elsewhere in the pattern, things went wrong
680        (an internal error was given). Such groups are now left in the compiled
681        pattern, with a new opcode that causes them to be skipped at execution
682        time.
683    
684    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
685        to the way PCRE behaves:
686    
687        (a) A lone ] character is dis-allowed (Perl treats it as data).
688    
689        (b) A back reference to an unmatched subpattern matches an empty string
690            (Perl fails the current match path).
691    
692        (c) A data ] in a character class must be notated as \] because if the
693            first data character in a class is ], it defines an empty class. (In
694            Perl it is not possible to have an empty class.) The empty class []
695            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
696            The negative empty class [^] matches any one character, independently
697            of the DOTALL setting.
698    
699    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
700        non-existent subpattern following a character class starting with ']' and
701        containing () gave an internal compiling error instead of "reference to
702        non-existent subpattern". Fortunately, when the pattern did exist, the
703        compiled code was correct. (When scanning forwards to check for the
704        existencd of the subpattern, it was treating the data ']' as terminating
705        the class, so got the count wrong. When actually compiling, the reference
706        was subsequently set up correctly.)
707    
708    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
709        it was being rejected as not supported by pcre_dfa_exec(), even though
710        other assertions are supported. I have made pcre_dfa_exec() support
711        (*FAIL).
712    
713    16. The implementation of 13c above involved the invention of a new opcode,
714        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
715        cannot be changed at match time, I realized I could make a small
716        improvement to matching performance by compiling OP_ALLANY instead of
717        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
718        on the OP_ANY path.
719    
720    17. Compiling pcretest on Windows with readline support failed without the
721        following two fixes: (1) Make the unistd.h include conditional on
722        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
723    
724    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
725        ncurses library to be included for pcretest when ReadLine support is
726        requested, but also to allow for it to be overridden. This patch came from
727        Daniel Bergström.
728    
729    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
730        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
731        any errors with the current Unicode tables. Thanks to Peter Kankowski for
732        spotting this.
733    
734    
735    Version 7.6 28-Jan-08
736    ---------------------
737    
738    1.  A character class containing a very large number of characters with
739        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
740        overflow.
741    
742    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
743        HAVE_LONG_LONG is not defined.
744    
745    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
746        bring them up to date and include new features. This patch includes:
747    
748        - Fixed PH's badly added libz and libbz2 support.
749        - Fixed a problem with static linking.
750        - Added pcredemo. [But later removed - see 7 below.]
751        - Fixed dftables problem and added an option.
752        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
753            HAVE_LONG_LONG.
754        - Added readline support for pcretest.
755        - Added an listing of the option settings after cmake has run.
756    
757    4.  A user submitted a patch to Makefile that makes it easy to create
758        "pcre.dll" under mingw when using Configure/Make. I added stuff to
759        Makefile.am that cause it to include this special target, without
760        affecting anything else. Note that the same mingw target plus all
761        the other distribution libraries and programs are now supported
762        when configuring with CMake (see 6 below) instead of with
763        Configure/Make.
764    
765    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
766        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
767        exported in the Windows port". It has not yet been confirmed that the patch
768        solves the problem, but it does no harm.
769    
770    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
771        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
772        with CMake, and also correct the comment about stack recursion.
773    
774    7.  Remove the automatic building of pcredemo from the ./configure system and
775        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
776        of a program that users should build themselves after PCRE is installed, so
777        building it automatically is not really right. What is more, it gave
778        trouble in some build environments.
779    
780    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
781    
782    
783    Version 7.5 10-Jan-08
784    ---------------------
785    
786    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
787        values in parens when parsing an RE using the C++ wrapper."
788    
789    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
790        Characters greater than 255 were excluded from the class instead of being
791        included.
792    
793    3.  The same bug as (2) above applied to negated POSIX classes such as
794        [:^space:].
795    
796    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
797        defined or documented. It seems to have been a typo for PCRE_STATIC, so
798        I have changed it.
799    
800    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
801        first named subpattern) and a construct such as (?&a) would reference the
802        first named subpattern whose name started with "a" (in other words, the
803        length check was missing). Both these problems are fixed. "Subpattern name
804        expected" is now given for (?&) (a zero-length name), and this patch also
805        makes it give the same error for \k'' (previously it complained that that
806        was a reference to a non-existent subpattern).
807    
808    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
809        this is right because (?- can be followed by option settings as well as by
810        digits. I have, however, made the messages clearer.
811    
812    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
813        than the number used in the conditional) now cause a compile-time error.
814        This is actually not compatible with Perl, which accepts such patterns, but
815        treats the conditional as always being FALSE (as PCRE used to), but it
816        seems to me that giving a diagnostic is better.
817    
818    8.  Change "alphameric" to the more common word "alphanumeric" in comments
819        and messages.
820    
821    9.  Fix two occurrences of "backslash" in comments that should have been
822        "backspace".
823    
824    10. Remove two redundant lines of code that can never be obeyed (their function
825        was moved elsewhere).
826    
827    11. The program that makes PCRE's Unicode character property table had a bug
828        which caused it to generate incorrect table entries for sequences of
829        characters that have the same character type, but are in different scripts.
830        It amalgamated them into a single range, with the script of the first of
831        them. In other words, some characters were in the wrong script. There were
832        thirteen such cases, affecting characters in the following ranges:
833    
834          U+002b0 - U+002c1
835          U+0060c - U+0060d
836          U+0061e - U+00612
837          U+0064b - U+0065e
838          U+0074d - U+0076d
839          U+01800 - U+01805
840          U+01d00 - U+01d77
841          U+01d9b - U+01dbf
842          U+0200b - U+0200f
843          U+030fc - U+030fe
844          U+03260 - U+0327f
845          U+0fb46 - U+0fbb1
846          U+10450 - U+1049d
847    
848    12. The -o option (show only the matching part of a line) for pcregrep was not
849        compatible with GNU grep in that, if there was more than one match in a
850        line, it showed only the first of them. It now behaves in the same way as
851        GNU grep.
852    
853    13. If the -o and -v options were combined for pcregrep, it printed a blank
854        line for every non-matching line. GNU grep prints nothing, and pcregrep now
855        does the same. The return code can be used to tell if there were any
856        non-matching lines.
857    
858    14. Added --file-offsets and --line-offsets to pcregrep.
859    
860    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
861        infinitely looping recursion. The bug was that positive lookaheads were not
862        being skipped when checking for a possible empty match (negative lookaheads
863        and both kinds of lookbehind were skipped).
864    
865    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
866        inclusion of <windows.h> to before rather than after the definition of
867        INVALID_FILE_ATTRIBUTES (patch from David Byron).
868    
869    17. Specifying a possessive quantifier with a specific limit for a Unicode
870        character property caused pcre_compile() to compile bad code, which led at
871        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
872        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
873        caused the error; without that there was no problem.
874    
875    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
876    
877    19. Added --enable-pcretest-libreadline.
878    
879    20. In pcrecpp.cc, the variable 'count' was incremented twice in
880        RE::GlobalReplace(). As a result, the number of replacements returned was
881        double what it should be. I removed one of the increments, but Craig sent a
882        later patch that removed the other one (the right fix) and added unit tests
883        that check the return values (which was not done before).
884    
885    21. Several CMake things:
886    
887        (1) Arranged that, when cmake is used on Unix, the libraries end up with
888            the names libpcre and libpcreposix, not just pcre and pcreposix.
889    
890        (2) The above change means that pcretest and pcregrep are now correctly
891            linked with the newly-built libraries, not previously installed ones.
892    
893        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
894    
895    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
896        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
897        UTF-8 newline character). The key issue is that the pattern starts .*;
898        this means that the match must be either at the beginning, or after a
899        newline. The bug was in the code for advancing after a failed match and
900        checking that the new position followed a newline. It was not taking
901        account of UTF-8 characters correctly.
902    
903    23. PCRE was behaving differently from Perl in the way it recognized POSIX
904        character classes. PCRE was not treating the sequence [:...:] as a
905        character class unless the ... were all letters. Perl, however, seems to
906        allow any characters between [: and :], though of course it rejects as
907        unknown any "names" that contain non-letters, because all the known class
908        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
909        for example, whereas PCRE did not - it did not recognize a POSIX character
910        class. This seemed a bit dangerous, so the code has been changed to be
911        closer to Perl. The behaviour is not identical to Perl, because PCRE will
912        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
913        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
914        Perl does, and where it didn't before.
915    
916    24. Rewrite so as to remove the single use of %n from pcregrep because in some
917        Windows environments %n is disabled by default.
918    
919    
920    Version 7.4 21-Sep-07
921    ---------------------
922    
923    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
924        means that a class such as [\s] counted as "explicit reference to CR or
925        LF". That isn't really right - the whole point of the change was to try to
926        help when there was an actual mention of one of the two characters. So now
927        the change happens only if \r or \n (or a literal CR or LF) character is
928        encountered.
929    
930    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
931        of both had grown to the point where there were only 3 bits left.
932        Fortunately, there was spare space in the data structure, and so I have
933        moved the internal flags into a new 16-bit field to free up more option
934        bits.
935    
936    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
937        but did not set the internal JCHANGED flag - either of these is enough to
938        control the way the "get" function works - but the PCRE_INFO_JCHANGED
939        facility is supposed to tell if (?J) was ever used, so now (?J) at the
940        start sets both bits.
941    
942    4.  Added options (at build time, compile time, exec time) to change \R from
943        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
944    
945    5.  doc/pcresyntax.html was missing from the distribution.
946    
947    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
948        compatibility, even though it is no longer used.
949    
950    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
951        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
952        windows.h file is present (where different names are used). [This was
953        reversed later after testing - see 16 below.]
954    
955    8.  Changed all #include <config.h> to #include "config.h". There were also
956        some further <pcre.h> cases that I changed to "pcre.h".
957    
958    9.  When pcregrep was used with the --colour option, it missed the line ending
959        sequence off the lines that it output.
960    
961    10. It was pointed out to me that arrays of string pointers cause lots of
962        relocations when a shared library is dynamically loaded. A technique of
963        using a single long string with a table of offsets can drastically reduce
964        these. I have refactored PCRE in four places to do this. The result is
965        dramatic:
966    
967          Originally:                          290
968          After changing UCP table:            187
969          After changing error message table:   43
970          After changing table of "verbs"       36
971          After changing table of Posix names   22
972    
973        Thanks to the folks working on Gregex for glib for this insight.
974    
975    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
976        unicode-properties was also set.
977    
978    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
979    
980    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
981        checked only for CRLF.
982    
983    14. Added casts to pcretest.c to avoid compiler warnings.
984    
985    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
986    
987    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
988        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
989        entirely. This removes changes made in 7 above.
990    
991    17. The CMake files have been updated, and there is now more information about
992        building with CMake in the NON-UNIX-USE document.
993    
994    
995    Version 7.3 28-Aug-07
996    ---------------------
997    
998     1. In the rejigging of the build system that eventually resulted in 7.1, the
999        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1000        brackets there is not right, since it causes compilers to look for an
1001        installed pcre.h, not the version that is in the source that is being
1002        compiled (which of course may be different). I have changed it back to:
1003    
1004          #include "pcre.h"
1005    
1006        I have a vague recollection that the change was concerned with compiling in
1007        different directories, but in the new build system, that is taken care of
1008        by the VPATH setting the Makefile.
1009    
1010     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1011        when the subject happened to end in the byte 0x85 (e.g. if the last
1012        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1013        characters but of course it shouldn't be taken as a newline when it is part
1014        of another character. The bug was that, for an unlimited repeat of . in
1015        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1016        characters when looking for a newline.
1017    
1018     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1019    
1020     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1021        in debug output.
1022    
1023     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1024        long printing in the pcrecpp unittest when running under MinGW.
1025    
1026     6. ESC_K was left out of the EBCDIC table.
1027    
1028     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1029        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1030        limit also applies to "virtual nesting" when a pattern is recursive, and in
1031        this case 1000 isn't so big. I have been able to remove this limit at the
1032        expense of backing off one optimization in certain circumstances. Normally,
1033        when pcre_exec() would call its internal match() function recursively and
1034        immediately return the result unconditionally, it uses a "tail recursion"
1035        feature to save stack. However, when a subpattern that can match an empty
1036        string has an unlimited repetition quantifier, it no longer makes this
1037        optimization. That gives it a stack frame in which to save the data for
1038        checking that an empty string has been matched. Previously this was taken
1039        from the 1000-entry workspace that had been reserved. So now there is no
1040        explicit limit, but more stack is used.
1041    
1042     8. Applied Daniel's patches to solve problems with the import/export magic
1043        syntax that is required for Windows, and which was going wrong for the
1044        pcreposix and pcrecpp parts of the library. These were overlooked when this
1045        problem was solved for the main library.
1046    
1047     9. There were some crude static tests to avoid integer overflow when computing
1048        the size of patterns that contain repeated groups with explicit upper
1049        limits. As the maximum quantifier is 65535, the maximum group length was
1050        set at 30,000 so that the product of these two numbers did not overflow a
1051        32-bit integer. However, it turns out that people want to use groups that
1052        are longer than 30,000 bytes (though not repeat them that many times).
1053        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1054        made it possible to implement the integer overflow checks in a much more
1055        dynamic way, which I have now done. The artificial limitation on group
1056        length has been removed - we now have only the limit on the total length of
1057        the compiled pattern, which depends on the LINK_SIZE setting.
1058    
1059    10. Fixed a bug in the documentation for get/copy named substring when
1060        duplicate names are permitted. If none of the named substrings are set, the
1061        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1062        empty string.
1063    
1064    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1065        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1066        because the ] is interpreted as the first data character and the
1067        terminating ] is not found. PCRE has been made compatible with Perl in this
1068        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1069        cause memory overwriting.
1070    
1071    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1072        string has been matched (to stop an infinite loop). It was not recognizing
1073        a conditional subpattern that could match an empty string if that
1074        subpattern was within another subpattern. For example, it looped when
1075        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1076        condition was not nested. This bug has been fixed.
1077    
1078    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1079        past the start of the subject in the presence of bytes with the top bit
1080        set, for example "\x8aBCD".
1081    
1082    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1083        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1084    
1085    14. Optimized (?!) to (*FAIL).
1086    
1087    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1088        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1089        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1090        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1091        does: it's just the validity check that is more restrictive.
1092    
1093    16. Inserted checks for integer overflows during escape sequence (backslash)
1094        processing, and also fixed erroneous offset values for syntax errors during
1095        backslash processing.
1096    
1097    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1098        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1099    
1100    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1101        caused an overrun.
1102    
1103    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1104        something other than just ASCII characters) inside a group that had an
1105        unlimited repeat caused a loop at compile time (while checking to see
1106        whether the group could match an empty string).
1107    
1108    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1109        [\P{Any}] did so. (Error in the code for printing property names.)
1110    
1111    21. An orphan \E inside a character class could cause a crash.
1112    
1113    22. A repeated capturing bracket such as (A)? could cause a wild memory
1114        reference during compilation.
1115    
1116    23. There are several functions in pcre_compile() that scan along a compiled
1117        expression for various reasons (e.g. to see if it's fixed length for look
1118        behind). There were bugs in these functions when a repeated \p or \P was
1119        present in the pattern. These operators have additional parameters compared
1120        with \d, etc, and these were not being taken into account when moving along
1121        the compiled data. Specifically:
1122    
1123        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1124            length.
1125    
1126        (b) An item such as \pL+ within a repeated group could cause crashes or
1127            loops.
1128    
1129        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1130            "reference to non-existent subpattern" error.
1131    
1132        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1133    
1134    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1135        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1136    
1137    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1138    
1139    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1140        character were causing crashes (broken optimization).
1141    
1142    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1143        \p or \P) caused a compile-time loop.
1144    
1145    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1146        break. For example, the unstudied pattern [\r\n]A does not match the string
1147        "\r\nA" because change 7.0/46 below moves the current point on by two
1148        characters after failing to match at the start. However, the pattern \nA
1149        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1150        the same is true. There doesn't seem any very clean way out of this, but
1151        what I have chosen to do makes the common cases work: PCRE now takes note
1152        of whether there can be an explicit match for \r or \n anywhere in the
1153        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1154        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1155        pattern has explicit CR or LF references.
1156    
1157    29. Added (*CR) etc for changing newline setting at start of pattern.
1158    
1159    
1160    Version 7.2 19-Jun-07
1161    ---------------------
1162    
1163     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1164        which is apparently normally available under Windows.
1165    
1166     2. Re-jig the pcregrep tests with different newline settings in an attempt
1167        to make them independent of the local environment's newline setting.
1168    
1169     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1170    
1171     4. Some of the "internals" tests were previously cut out when the link size
1172        was not 2, because the output contained actual offsets. The recent new
1173        "Z" feature of pcretest means that these can be cut out, making the tests
1174        usable with all link sizes.
1175    
1176     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1177        stack recursion. This gives a massive performance boost under BSD, but just
1178        a small improvement under Linux. However, it saves one field in the frame
1179        in all cases.
1180    
1181     6. Added more features from the forthcoming Perl 5.10:
1182    
1183        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1184            recursion call. It refers to the nth most recently opened parentheses.
1185    
1186        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1187            to be opened parentheses.
1188    
1189        (c) Conditions that refer to capturing parentheses can be specified
1190            relatively, for example, (?(-2)... or (?(+3)...
1191    
1192        (d) \K resets the start of the current match so that everything before
1193            is not part of it.
1194    
1195        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1196    
1197        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1198            reference syntax.
1199    
1200        (g) (?| introduces a group in which the numbering of parentheses in each
1201            alternative starts with the same number.
1202    
1203        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1204    
1205     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1206        PCRE_INFO_JCHANGED.
1207    
1208     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1209        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1210        for detecting groups that can match an empty string.
1211    
1212     9. A pattern with a very large number of alternatives (more than several
1213        hundred) was running out of internal workspace during the pre-compile
1214        phase, where pcre_compile() figures out how much memory will be needed. A
1215        bit of new cunning has reduced the workspace needed for groups with
1216        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1217        workspace instead of running out of the 4096 that are available.
1218    
1219    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1220    
1221    11. Applied patch from Google to remove an optimization that didn't quite work.
1222        The report of the bug said:
1223    
1224          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1225          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1226          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1227    
1228    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1229        it matched the wrong number of bytes.
1230    
1231    
1232    Version 7.1 24-Apr-07
1233    ---------------------
1234    
1235     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1236        that is more "standard", making use of automake and other Autotools. There
1237        is some re-arrangement of the files and adjustment of comments consequent
1238        on this.
1239    
1240     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1241        for recursive directory scanning broke on some systems because the files
1242        are not scanned in any specific order and on different systems the order
1243        was different. A call to "sort" has been inserted into RunGrepTest for the
1244        approprate test as a short-term fix. In the longer term there may be an
1245        alternative.
1246    
1247     3. I had an email from Eric Raymond about problems translating some of PCRE's
1248        man pages to HTML (despite the fact that I distribute HTML pages, some
1249        people do their own conversions for various reasons). The problems
1250        concerned the use of low-level troff macros .br and .in. I have therefore
1251        removed all such uses from the man pages (some were redundant, some could
1252        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1253        HTML has been updated to handle .nf/.fi and to complain if it encounters
1254        .br or .in.
1255    
1256     4. Updated comments in configure.ac that get placed in config.h.in and also
1257        arranged for config.h to be included in the distribution, with the name
1258        config.h.generic, for the benefit of those who have to compile without
1259        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1260    
1261     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1262        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1263        makevp.bat for the current PCRE, using the additional files
1264        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1265    
1266     6. A Windows user reported a minor discrepancy with test 2, which turned out
1267        to be caused by a trailing space on an input line that had got lost in his
1268        copy. The trailing space was an accident, so I've just removed it.
1269    
1270     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1271        that is needed.
1272    
1273     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1274        as "const" (a) because they are and (b) because it helps the PHP
1275        maintainers who have recently made a script to detect big data structures
1276        in the php code that should be moved to the .rodata section. I remembered
1277        to update Builducptable as well, so it won't revert if ucptable.h is ever
1278        re-created.
1279    
1280     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1281        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1282        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1283        support is not required. This saves 1.5-2K of code, which is important in
1284        some applications.
1285    
1286        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1287        so as not to refer to the tables, even though these functions will never be
1288        called when UTF-8 support is disabled. Otherwise there are problems with a
1289        shared library.
1290    
1291    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1292    
1293        (a) It was defining its arguments as char * instead of void *.
1294    
1295        (b) It was assuming that all moves were upwards in memory; this was true
1296            a long time ago when I wrote it, but is no longer the case.
1297    
1298        The emulated memove() is provided for those environments that have neither
1299        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1300        is clearly not the case, as these two bugs were recently reported.
1301    
1302    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1303        and Detrail to create the HTML documentation, the .txt form of the man
1304        pages, and it removes trailing spaces from listed files. It also creates
1305        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1306        case, it wraps all the #defines with #ifndefs. This script should be run
1307        before "make dist".
1308    
1309    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1310        with Unicode property support.
1311    
1312        (a) For a maximizing quantifier, if the two different cases of the
1313            character were of different lengths in their UTF-8 codings (there are
1314            some cases like this - I found 11), and the matching function had to
1315            back up over a mixture of the two cases, it incorrectly assumed they
1316            were both the same length.
1317    
1318        (b) When PCRE was configured to use the heap rather than the stack for
1319            recursion during matching, it was not correctly preserving the data for
1320            the other case of a UTF-8 character when checking ahead for a match
1321            while processing a minimizing repeat. If the check also involved
1322            matching a wide character, but failed, corruption could cause an
1323            erroneous result when trying to check for a repeat of the original
1324            character.
1325    
1326    13. Some tidying changes to the testing mechanism:
1327    
1328        (a) The RunTest script now detects the internal link size and whether there
1329            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1330            values substituted by "configure". (The RunGrepTest script already did
1331            this for UTF-8.) The configure.ac script no longer substitutes the
1332            relevant variables.
1333    
1334        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1335            with length and offset values. This means that the output is different
1336            for different internal link sizes. Test 2 is skipped for link sizes
1337            other than 2 because of this, bypassing the problem. Unfortunately,
1338            there was also a test in test 3 (the locale tests) that used /B and
1339            failed for link sizes other than 2. Rather than cut the whole test out,
1340            I have added a new /Z option to pcretest that replaces the length and
1341            offset values with spaces. This is now used to make test 3 independent
1342            of link size. (Test 2 will be tidied up later.)
1343    
1344    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1345        segmentation fault instead of returning the appropriate error message.
1346    
1347    15. In multiline mode when the newline sequence was set to "any", the pattern
1348        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1349        This doesn't seem right; it now treats the CRLF combination as the line
1350        ending, and so does not match in that case. It's only a pattern such as ^$
1351        that would hit this one: something like ^ABC$ would have failed after \r
1352        and then tried again after \r\n.
1353    
1354    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1355        in an attempt to make files that differ only in their line terminators
1356        compare equal. This works on Linux.
1357    
1358    17. Under certain error circumstances pcregrep might try to free random memory
1359        as it exited. This is now fixed, thanks to valgrind.
1360    
1361    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1362        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1363        was because its rules for how to advance for /g after matching an empty
1364        string at the end of a line did not allow for this case. They now check for
1365        it specially.
1366    
1367    20. pcretest is supposed to handle patterns and data of any length, by
1368        extending its buffers when necessary. It was getting this wrong when the
1369        buffer for a data line had to be extended.
1370    
1371    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1372        CRLF as a newline sequence.
1373    
1374    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1375        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1376        I have nevertheless tidied it up.
1377    
1378    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1379    
1380    24. Added a man page for pcre-config.
1381    
1382    
1383    Version 7.0 19-Dec-06
1384    ---------------------
1385    
1386     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1387        moving to gcc 4.1.1.
1388    
1389     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1390        sys/time.h, which is documented as needed for this function. It doesn't
1391        seem to matter on Linux, but it showed up on some releases of OS X.
1392    
1393     3. It seems that there are systems where bytes whose values are greater than
1394        127 match isprint() in the "C" locale. The "C" locale should be the
1395        default when a C program starts up. In most systems, only ASCII printing
1396        characters match isprint(). This difference caused the output from pcretest
1397        to vary, making some of the tests fail. I have changed pcretest so that:
1398    
1399        (a) When it is outputting text in the compiled version of a pattern, bytes
1400            other than 32-126 are always shown as hex escapes.
1401    
1402        (b) When it is outputting text that is a matched part of a subject string,
1403            it does the same, unless a different locale has been set for the match
1404            (using the /L modifier). In this case, it uses isprint() to decide.
1405    
1406     4. Fixed a major bug that caused incorrect computation of the amount of memory
1407        required for a compiled pattern when options that changed within the
1408        pattern affected the logic of the preliminary scan that determines the
1409        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1410        that the computed length was too small. The symptoms of this bug were
1411        either the PCRE error "internal error: code overflow" from pcre_compile(),
1412        or a glibc crash with a message such as "pcretest: free(): invalid next
1413        size (fast)". Examples of patterns that provoked this bug (shown in
1414        pcretest format) are:
1415    
1416          /(?-x: )/x
1417          /(?x)(?-x: \s*#\s*)/
1418          /((?i)[\x{c0}])/8
1419          /(?i:[\x{c0}])/8
1420    
1421        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1422        is now done differently.
1423    
1424     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1425        wrapper classes; (b) implement a new function in the C++ scanner that is
1426        more efficient than the old way of doing things because it avoids levels of
1427        recursion in the regex matching; (c) add a paragraph to the documentation
1428        for the FullMatch() function.
1429    
1430     6. The escape sequence \n was being treated as whatever was defined as
1431        "newline". Not only was this contrary to the documentation, which states
1432        that \n is character 10 (hex 0A), but it also went horribly wrong when
1433        "newline" was defined as CRLF. This has been fixed.
1434    
1435     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1436        was being set to -1 for the "end of line" case (supposedly a value that no
1437        character can have). Though this value is never used (the check for end of
1438        line is "zero bytes in current character"), it caused compiler complaints.
1439        I've changed it to 0xffffffff.
1440    
1441     8. In pcre_version.c, the version string was being built by a sequence of
1442        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1443        string (as it is for production releases) called a macro with an empty
1444        argument. The C standard says the result of this is undefined. The gcc
1445        compiler treats it as an empty string (which was what was wanted) but it is
1446        reported that Visual C gives an error. The source has been hacked around to
1447        avoid this problem.
1448    
1449     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1450        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1451        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1452        of them did).
1453    
1454    10. Originally, pcretest opened its input and output without "b"; then I was
1455        told that "b" was needed in some environments, so it was added for release
1456        5.0 to both the input and output. (It makes no difference on Unix-like
1457        systems.) Later I was told that it is wrong for the input on Windows. I've
1458        now abstracted the modes into two macros, to make it easier to fiddle with
1459        them, and removed "b" from the input mode under Windows.
1460    
1461    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1462    
1463    12. Added -help and --help to pcretest as an official way of being reminded
1464        of the options.
1465    
1466    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1467        and pcrecpp.cc because they annoy compilers at high warning levels.
1468    
1469    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1470    
1471    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1472        scripts are not C programs :-) and which was not noticed because it works
1473        on Linux.
1474    
1475    16. pcretest is supposed to handle any length of pattern and data line (as one
1476        line or as a continued sequence of lines) by extending its input buffer if
1477        necessary. This feature was broken for very long pattern lines, leading to
1478        a string of junk being passed to pcre_compile() if the pattern was longer
1479        than about 50K.
1480    
1481    17. I have done a major re-factoring of the way pcre_compile() computes the
1482        amount of memory needed for a compiled pattern. Previously, there was code
1483        that made a preliminary scan of the pattern in order to do this. That was
1484        OK when PCRE was new, but as the facilities have expanded, it has become
1485        harder and harder to keep it in step with the real compile phase, and there
1486        have been a number of bugs (see for example, 4 above). I have now found a
1487        cunning way of running the real compile function in a "fake" mode that
1488        enables it to compute how much memory it would need, while actually only
1489        ever using a few hundred bytes of working memory and without too many
1490        tests of the mode. This should make future maintenance and development
1491        easier. A side effect of this work is that the limit of 200 on the nesting
1492        depth of parentheses has been removed (though this was never a serious
1493        limitation, I suspect). However, there is a downside: pcre_compile() now
1494        runs more slowly than before (30% or more, depending on the pattern). I
1495        hope this isn't a big issue. There is no effect on runtime performance.
1496    
1497    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1498        newline (only possible for the last line of a file) and it was a
1499        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1500    
1501    19. Added additional timing features to pcretest. (1) The -tm option now times
1502        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1503        separate command line item, by a number that specifies the number of
1504        repeats to use when timing. The default is 50000; this gives better
1505        precision, but takes uncomfortably long for very large patterns.
1506    
1507    20. Extended pcre_study() to be more clever in cases where a branch of a
1508        subpattern has no definite first character. For example, (a*|b*)[cd] would
1509        previously give no result from pcre_study(). Now it recognizes that the
1510        first character must be a, b, c, or d.
1511    
1512    21. There was an incorrect error "recursive call could loop indefinitely" if
1513        a subpattern (or the entire pattern) that was being tested for matching an
1514        empty string contained only one non-empty item after a nested subpattern.
1515        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1516        incorrectly, because the \d was being skipped in the check.
1517    
1518    22. The pcretest program now has a new pattern option /B and a command line
1519        option -b, which is equivalent to adding /B to every pattern. This causes
1520        it to show the compiled bytecode, without the additional information that
1521        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1522        is the same as /B/I).
1523    
1524    23. A new optimization is now able automatically to treat some sequences such
1525        as a*b as a*+b. More specifically, if something simple (such as a character
1526        or a simple class like \d) has an unlimited quantifier, and is followed by
1527        something that cannot possibly match the quantified thing, the quantifier
1528        is automatically "possessified".
1529    
1530    24. A recursive reference to a subpattern whose number was greater than 39
1531        went wrong under certain circumstances in UTF-8 mode. This bug could also
1532        have affected the operation of pcre_study().
1533    
1534    25. Realized that a little bit of performance could be had by replacing
1535        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1536    
1537    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1538    
1539    27. Possessive quantifiers such as a++ were previously implemented by turning
1540        them into atomic groups such as ($>a+). Now they have their own opcodes,
1541        which improves performance. This includes the automatically created ones
1542        from 23 above.
1543    
1544    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1545        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1546        the first matched character to be a colon. This applied both to named and
1547        numbered groups.
1548    
1549    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1550    
1551    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1552        building PCRE on Windows easier, so I have included it in the distribution.
1553    
1554    31. There is now a check in pcretest against a ridiculously large number being
1555        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1556        loop, the loop is abandoned.
1557    
1558    32. Forward references to subpatterns in conditions such as (?(2)...) where
1559        subpattern 2 is defined later cause pcre_compile() to search forwards in
1560        the pattern for the relevant set of parentheses. This search went wrong
1561        when there were unescaped parentheses in a character class, parentheses
1562        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1563    
1564    33. "Subroutine" calls and backreferences were previously restricted to
1565        referencing subpatterns earlier in the regex. This restriction has now
1566        been removed.
1567    
1568    34. Added a number of extra features that are going to be in Perl 5.10. On the
1569        whole, these are just syntactic alternatives for features that PCRE had
1570        previously implemented using the Python syntax or my own invention. The
1571        other formats are all retained for compatibility.
1572    
1573        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1574            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1575            also .NET compatible.
1576    
1577        (b) A recursion or subroutine call to a named group can now be defined as
1578            (?&name) as well as (?P>name).
1579    
1580        (c) A backreference to a named group can now be defined as \k<name> or
1581            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1582            5.10, are also .NET compatible.
1583    
1584        (d) A conditional reference to a named group can now use the syntax
1585            (?(<name>) or (?('name') as well as (?(name).
1586    
1587        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1588            groups (named and numbered) that are never evaluated inline, but can be
1589            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1590            is always false. There may be only one alternative in such a group.
1591    
1592        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1593            as the simple (?(R). The condition is true only if the most recent
1594            recursion is that of the given number or name. It does not search out
1595            through the entire recursion stack.
1596    
1597        (g) The escape \gN or \g{N} has been added, where N is a positive or
1598            negative number, specifying an absolute or relative reference.
1599    
1600    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1601        some "unreachable code" warnings.
1602    
1603    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1604        things, this adds five new scripts.
1605    
1606    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1607        There were also incompatibilities regarding the handling of \Q..\E inside
1608        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1609        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1610    
1611    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1612        matches an empty string, and forcibly breaks the loop. There were bugs in
1613        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1614        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1615        separate and independent bugs (that affected different cases) have been
1616        fixed.
1617    
1618    39. Refactored the code to abolish the use of different opcodes for small
1619        capturing bracket numbers. This is a tidy that I avoided doing when I
1620        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1621        The new approach is not only tidier, it makes it possible to reduce the
1622        memory needed to fix the previous bug (38).
1623    
1624    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1625        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1626        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1627        mode.
1628    
1629    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1630        report.
1631    
1632    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1633        copy construction and assignment in the C++ wrapper.
1634    
1635    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1636        couple of bugs that could have given wrong results in the "--newline=crlf"
1637        case.
1638    
1639    44. Added a number of casts and did some reorganization of signed/unsigned int
1640        variables following suggestions from Dair Grant. Also renamed the variable
1641        "this" as "item" because it is a C++ keyword.
1642    
1643    45. Arranged for dftables to add
1644    
1645          #include "pcre_internal.h"
1646    
1647        to pcre_chartables.c because without it, gcc 4.x may remove the array
1648        definition from the final binary if PCRE is built into a static library and
1649        dead code stripping is activated.
1650    
1651    46. For an unanchored pattern, if a match attempt fails at the start of a
1652        newline sequence, and the newline setting is CRLF or ANY, and the next two
1653        characters are CRLF, advance by two characters instead of one.
1654    
1655    
1656  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
1657  ---------------------  ---------------------
1658    

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