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revision 190 by ph10, Thu Jul 19 10:38:20 2007 UTC revision 538 by ph10, Wed Jun 9 19:30:57 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 05-Jul-07  Version 8.10 03-Jun-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        (#976).
47    
48    12. If a pattern that was studied started with a repeated Unicode property
49        test, for example, \p{Nd}+, there was the theoretical possibility of
50        setting up an incorrect bitmap of starting bytes, but fortunately it could
51        not have actually happened in practice until change 8 above was made (it
52        added property types that matched character-matching opcodes).
53    
54    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
55        possible starting bytes for non-anchored patterns.
56    
57    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
58        \R, and also a number of cases that involve Unicode properties, both
59        explicit and implicit when PCRE_UCP is set.
60    
61    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
62        input, it could crash or give wrong results if characters with values
63        greater than 0xc0 were present in the subject string. (Detail: it assumed
64        UTF-8 input when processing these items.)
65    
66    16. Added a lot of (int) casts to avoid compiler warnings in systems where
67        size_t is 64-bit (#991).
68    
69    17. Added a check for running out of memory when PCRE is compiled with
70        --disable-stack-for-recursion (#990).
71    
72    18. If the last data line in a file for pcretest does not have a newline on
73        the end, a newline was missing in the output.
74    
75    19. The default pcre_chartables.c file recognizes only ASCII characters (values
76        less than 128) in its various bitmaps. However, there is a facility for
77        generating tables according to the current locale when PCRE is compiled. It
78        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
79        characters, are recognized by isspace() and therefore were getting set in
80        these tables. This caused a problem in UTF-8 mode when pcre_study() was
81        used to create a list of bytes that can start a match. For \s, it was
82        including 0x85 and 0xa0, which of course cannot start UTF-8 characters. I
83        have changed the code so that only real ASCII characters (less than 128)
84        are set in this case because the \s etc escapes are documented as
85        recognizing only ASCII characters. (When PCRE_UCP is set - see 9 above -
86        the code is different altogether.)
87    
88    
89    Version 8.02 19-Mar-2010
90    ------------------------
91    
92    1.  The Unicode data tables have been updated to Unicode 5.2.0.
93    
94    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
95        configured.
96    
97    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
98        original author of that file, following a query about its status.
99    
100    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
101        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
102    
103    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
104        quantifier applied to a forward-referencing subroutine call, could compile
105        incorrect code or give the error "internal error: previously-checked
106        referenced subpattern not found".
107    
108    6.  Both MS Visual Studio and Symbian OS have problems with initializing
109        variables to point to external functions. For these systems, therefore,
110        pcre_malloc etc. are now initialized to local functions that call the
111        relevant global functions.
112    
113    7.  There were two entries missing in the vectors called coptable and poptable
114        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
115        I've fixed the data, and added a kludgy way of testing at compile time that
116        the lengths are correct (equal to the number of opcodes).
117    
118    8.  Following on from 7, I added a similar kludge to check the length of the
119        eint vector in pcreposix.c.
120    
121    9.  Error texts for pcre_compile() are held as one long string to avoid too
122        much relocation at load time. To find a text, the string is searched,
123        counting zeros. There was no check for running off the end of the string,
124        which could happen if a new error number was added without updating the
125        string.
126    
127    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
128    
129    11. \K was not working if it appeared in an atomic group or in a group that
130        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
131        \K is "not well defined" if used in an assertion. PCRE now accepts it if
132        the assertion is positive, but not if it is negative.
133    
134    12. Change 11 fortuitously reduced the size of the stack frame used in the
135        "match()" function of pcre_exec.c by one pointer. Forthcoming
136        implementation of support for (*MARK) will need an extra pointer on the
137        stack; I have reserved it now, so that the stack frame size does not
138        decrease.
139    
140    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
141        item in branch that calls a recursion is a subroutine call - as in the
142        second branch in the above example - was incorrectly given the compile-
143        time error "recursive call could loop indefinitely" because pcre_compile()
144        was not correctly checking the subroutine for matching a non-empty string.
145    
146    14. The checks for overrunning compiling workspace could trigger after an
147        overrun had occurred. This is a "should never occur" error, but it can be
148        triggered by pathological patterns such as hundreds of nested parentheses.
149        The checks now trigger 100 bytes before the end of the workspace.
150    
151    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
152    
153    
154    Version 8.01 19-Jan-2010
155    ------------------------
156    
157    1.  If a pattern contained a conditional subpattern with only one branch (in
158        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
159        computed the wrong minimum data length (which is of course zero for such
160        subpatterns). This could cause incorrect "no match" results.
161    
162    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
163        the pattern is reset in the first branch, pcre_compile() failed with
164        "internal error: code overflow at offset...". This happened only when
165        the reset was to the original external option setting. (An optimization
166        abstracts leading options settings into an external setting, which was the
167        cause of this.)
168    
169    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
170        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
171        assertion pattern did not match (meaning that the assertion was true), it
172        was incorrectly treated as false if the SKIP had been reached during the
173        matching. This also applied to assertions used as conditions.
174    
175    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
176        assertion subpattern, including such a pattern used as a condition,
177        unpredictable results occurred, instead of the error return
178        PCRE_ERROR_DFA_UITEM.
179    
180    5.  The C++ GlobalReplace function was not working like Perl for the special
181        situation when an empty string is matched. It now does the fancy magic
182        stuff that is necessary.
183    
184    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
185        removed. (These were left over from very, very early versions of PCRE.)
186    
187    7.  Some cosmetic changes to the code to make life easier when compiling it
188        as part of something else:
189    
190        (a) Change DEBUG to PCRE_DEBUG.
191    
192        (b) In pcre_compile(), rename the member of the "branch_chain" structure
193            called "current" as "current_branch", to prevent a collision with the
194            Linux macro when compiled as a kernel module.
195    
196        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
197            prevent a collision with the Linux macro when compiled as a kernel
198            module.
199    
200    8.  In pcre_compile() there are some checks for integer overflows that used to
201        cast potentially large values to (double). This has been changed to that
202        when building, a check for int64_t is made, and if it is found, it is used
203        instead, thus avoiding the use of floating point arithmetic. (There is no
204        other use of FP in PCRE.) If int64_t is not found, the fallback is to
205        double.
206    
207    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
208        2005 (difference between two addresses compared to an unsigned value).
209    
210    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
211        custom one, because of the following reported problem in Windows:
212    
213          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
214              under Win32.
215          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
216              therefore missing the function definition.
217          - The compiler thus generates a "C" signature for the test function.
218          - The linker fails to find the "C" function.
219          - PCRE fails to configure if asked to do so against libbz2.
220    
221    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
222        messages were output:
223    
224          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
225          rerunning libtoolize, to keep the correct libtool macros in-tree.
226          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
227    
228        I have done both of these things.
229    
230    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
231        most of the time, it *can* run out if it is given a pattern that contains a
232        runaway infinite recursion. I updated the discussion in the pcrestack man
233        page.
234    
235    13. Now that we have gone to the x.xx style of version numbers, the minor
236        version may start with zero. Using 08 or 09 is a bad idea because users
237        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
238        interpreted as invalid octal numbers. I've updated the previous comment in
239        configure.ac, and also added a check that gives an error if 08 or 09 are
240        used.
241    
242    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
243        causing partial matching to fail when the end of the subject matched \W
244        in a UTF-8 pattern where \W was quantified with a minimum of 3.
245    
246    15. There were some discrepancies between the declarations in pcre_internal.h
247        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
248        their definitions. The declarations used "const uschar *" and the
249        definitions used USPTR. Even though USPTR is normally defined as "const
250        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
251        reported that: "This difference in casting confuses some C++ compilers, for
252        example, SunCC recognizes above declarations as different functions and
253        generates broken code for hbpcre." I have changed the declarations to use
254        USPTR.
255    
256    16. GNU libtool is named differently on some systems. The autogen.sh script now
257        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
258        (FreeBSD).
259    
260    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
261        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
262        comment: "Figure out how to create a longlong from a string: strtoll and
263        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
264        instance, but it only takes 2 args instead of 3!"
265    
266    18. A subtle bug concerned with back references has been fixed by a change of
267        specification, with a corresponding code fix. A pattern such as
268        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
269        refers, was giving matches when it shouldn't. For example, xa=xaaa would
270        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
271        same bug. Such groups have to be quantified to be useful, or contained
272        inside another quantified group. (If there's no repetition, the reference
273        can never match.) The problem arises because, having left the group and
274        moved on to the rest of the pattern, a later failure that backtracks into
275        the group uses the captured value from the final iteration of the group
276        rather than the correct earlier one. I have fixed this in PCRE by forcing
277        any group that contains a reference to itself to be an atomic group; that
278        is, there cannot be any backtracking into it once it has completed. This is
279        similar to recursive and subroutine calls.
280    
281    
282    Version 8.00 19-Oct-09
283    ----------------------
284    
285    1.  The table for translating pcre_compile() error codes into POSIX error codes
286        was out-of-date, and there was no check on the pcre_compile() error code
287        being within the table. This could lead to an OK return being given in
288        error.
289    
290    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
291        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
292        in a Windows environment.
293    
294    3.  The pcregrep --count option prints the count for each file even when it is
295        zero, as does GNU grep. However, pcregrep was also printing all files when
296        --files-with-matches was added. Now, when both options are given, it prints
297        counts only for those files that have at least one match. (GNU grep just
298        prints the file name in this circumstance, but including the count seems
299        more useful - otherwise, why use --count?) Also ensured that the
300        combination -clh just lists non-zero counts, with no names.
301    
302    4.  The long form of the pcregrep -F option was incorrectly implemented as
303        --fixed_strings instead of --fixed-strings. This is an incompatible change,
304        but it seems right to fix it, and I didn't think it was worth preserving
305        the old behaviour.
306    
307    5.  The command line items --regex=pattern and --regexp=pattern were not
308        recognized by pcregrep, which required --regex pattern or --regexp pattern
309        (with a space rather than an '='). The man page documented the '=' forms,
310        which are compatible with GNU grep; these now work.
311    
312    6.  No libpcreposix.pc file was created for pkg-config; there was just
313        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
314    
315    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
316        when UCP support is not needed, by modifying the Python script that
317        generates it from Unicode data files. This should not matter if the module
318        is correctly used as a library, but I received one complaint about 50K of
319        unwanted data. My guess is that the person linked everything into his
320        program rather than using a library. Anyway, it does no harm.
321    
322    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
323        was a minimum greater than 1 for a wide character in a possessive
324        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
325        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
326        character. Chaos in the form of incorrect output or a compiling loop could
327        result.
328    
329    9.  The restrictions on what a pattern can contain when partial matching is
330        requested for pcre_exec() have been removed. All patterns can now be
331        partially matched by this function. In addition, if there are at least two
332        slots in the offset vector, the offset of the earliest inspected character
333        for the match and the offset of the end of the subject are set in them when
334        PCRE_ERROR_PARTIAL is returned.
335    
336    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
337        synonymous with PCRE_PARTIAL, for backwards compatibility, and
338        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
339        and may be more useful for multi-segment matching.
340    
341    11. Partial matching with pcre_exec() is now more intuitive. A partial match
342        used to be given if ever the end of the subject was reached; now it is
343        given only if matching could not proceed because another character was
344        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
345        string "Z", which now yields "no match" instead of "partial match". In the
346        case of pcre_dfa_exec(), "no match" is given if every matching path for the
347        final character ended with (*FAIL).
348    
349    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
350        if the pattern had a "must contain" character that was already found in the
351        earlier partial match, unless partial matching was again requested. For
352        example, with the pattern /dog.(body)?/, the "must contain" character is
353        "g". If the first part-match was for the string "dog", restarting with
354        "sbody" failed. This bug has been fixed.
355    
356    13. The string returned by pcre_dfa_exec() after a partial match has been
357        changed so that it starts at the first inspected character rather than the
358        first character of the match. This makes a difference only if the pattern
359        starts with a lookbehind assertion or \b or \B (\K is not supported by
360        pcre_dfa_exec()). It's an incompatible change, but it makes the two
361        matching functions compatible, and I think it's the right thing to do.
362    
363    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
364        so that the demonstration program is easily available in environments where
365        PCRE has not been installed from source.
366    
367    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
368        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
369        library.
370    
371    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
372        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
373        is not the first non-POSIX option to be added. Clearly some people find
374        these options useful.
375    
376    17. If a caller to the POSIX matching function regexec() passes a non-zero
377        value for nmatch with a NULL value for pmatch, the value of
378        nmatch is forced to zero.
379    
380    18. RunGrepTest did not have a test for the availability of the -u option of
381        the diff command, as RunTest does. It now checks in the same way as
382        RunTest, and also checks for the -b option.
383    
384    19. If an odd number of negated classes containing just a single character
385        interposed, within parentheses, between a forward reference to a named
386        subpattern and the definition of the subpattern, compilation crashed with
387        an internal error, complaining that it could not find the referenced
388        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
389        [The bug was that it was starting one character too far in when skipping
390        over the character class, thus treating the ] as data rather than
391        terminating the class. This meant it could skip too much.]
392    
393    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
394        /g option in pcretest when the pattern contains \K, which makes it possible
395        to have an empty string match not at the start, even when the pattern is
396        anchored. Updated pcretest and pcredemo to use this option.
397    
398    21. If the maximum number of capturing subpatterns in a recursion was greater
399        than the maximum at the outer level, the higher number was returned, but
400        with unset values at the outer level. The correct (outer level) value is
401        now given.
402    
403    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
404        PCRE did not set those parentheses (unlike Perl). I have now found a way to
405        make it do so. The string so far is captured, making this feature
406        compatible with Perl.
407    
408    23. The tests have been re-organized, adding tests 11 and 12, to make it
409        possible to check the Perl 5.10 features against Perl 5.10.
410    
411    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
412        pattern matches a fixed length string. PCRE did not allow this; now it
413        does. Neither allows recursion.
414    
415    25. I finally figured out how to implement a request to provide the minimum
416        length of subject string that was needed in order to match a given pattern.
417        (It was back references and recursion that I had previously got hung up
418        on.) This code has now been added to pcre_study(); it finds a lower bound
419        to the length of subject needed. It is not necessarily the greatest lower
420        bound, but using it to avoid searching strings that are too short does give
421        some useful speed-ups. The value is available to calling programs via
422        pcre_fullinfo().
423    
424    26. While implementing 25, I discovered to my embarrassment that pcretest had
425        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
426        study optimizations had never been tested with that matching function.
427        Oops. What is worse, even when it was passed study data, there was a bug in
428        pcre_dfa_exec() that meant it never actually used it. Double oops. There
429        were also very few tests of studied patterns with pcre_dfa_exec().
430    
431    27. If (?| is used to create subpatterns with duplicate numbers, they are now
432        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
433        on the other side of the coin, they are no longer allowed to have different
434        names, because these cannot be distinguished in PCRE, and this has caused
435        confusion. (This is a difference from Perl.)
436    
437    28. When duplicate subpattern names are present (necessarily with different
438        numbers, as required by 27 above), and a test is made by name in a
439        conditional pattern, either for a subpattern having been matched, or for
440        recursion in such a pattern, all the associated numbered subpatterns are
441        tested, and the overall condition is true if the condition is true for any
442        one of them. This is the way Perl works, and is also more like the way
443        testing by number works.
444    
445    
446    Version 7.9 11-Apr-09
447    ---------------------
448    
449    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
450        (pcretest), all targets were linked against these libraries. This included
451        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
452        libraries. This caused unwanted dependencies to be created. This problem
453        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
454        pcretest is linked with readline.
455    
456    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
457        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
458        moved outside it again, because FALSE and TRUE are already defined in AIX,
459        but BOOL is not.
460    
461    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
462        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
463    
464    4.  The pcregrep documentation said spaces were inserted as well as colons (or
465        hyphens) following file names and line numbers when outputting matching
466        lines. This is not true; no spaces are inserted. I have also clarified the
467        wording for the --colour (or --color) option.
468    
469    5.  In pcregrep, when --colour was used with -o, the list of matching strings
470        was not coloured; this is different to GNU grep, so I have changed it to be
471        the same.
472    
473    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
474        each matching line was coloured. Now it goes on to look for further matches
475        of any of the test patterns, which is the same behaviour as GNU grep.
476    
477    7.  A pattern that could match an empty string could cause pcregrep to loop; it
478        doesn't make sense to accept an empty string match in pcregrep, so I have
479        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
480        seems to be how GNU grep behaves.
481    
482    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
483        start or after a newline", because the conditional assertion was not being
484        correctly handled. The rule now is that both the assertion and what follows
485        in the first alternative must satisfy the test.
486    
487    9.  If auto-callout was enabled in a pattern with a conditional group whose
488        condition was an assertion, PCRE could crash during matching, both with
489        pcre_exec() and pcre_dfa_exec().
490    
491    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
492        used for matching.
493    
494    11. Unicode property support in character classes was not working for
495        characters (bytes) greater than 127 when not in UTF-8 mode.
496    
497    12. Added the -M command line option to pcretest.
498    
499    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
500    
501    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
502    
503    16. Added comments and documentation about mis-use of no_arg in the C++
504        wrapper.
505    
506    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
507        from Martin Jerabek that uses macro names for all relevant character and
508        string constants.
509    
510    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
511        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
512        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
513        these, but not everybody uses configure.
514    
515    19. A conditional group that had only one branch was not being correctly
516        recognized as an item that could match an empty string. This meant that an
517        enclosing group might also not be so recognized, causing infinite looping
518        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
519        with the subject "ab", where knowledge that the repeated group can match
520        nothing is needed in order to break the loop.
521    
522    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
523        exec(), but without supplying a callout function, matching went wrong.
524    
525    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
526        leak if the size of the offset vector was greater than 30. When the vector
527        is smaller, the saved offsets during recursion go onto a local stack
528        vector, but for larger vectors malloc() is used. It was failing to free
529        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
530        error, in fact).
531    
532    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
533        heapframe that is used only when UTF-8 support is enabled. This caused no
534        problem, but was untidy.
535    
536    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
537        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
538        included within another project.
539    
540    24. Steven Van Ingelgem's patches to add more options to the CMake support,
541        slightly modified by me:
542    
543          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
544              not building pcregrep.
545    
546          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
547              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
548    
549    25. Forward references, both numeric and by name, in patterns that made use of
550        duplicate group numbers, could behave incorrectly or give incorrect errors,
551        because when scanning forward to find the reference group, PCRE was not
552        taking into account the duplicate group numbers. A pattern such as
553        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
554    
555    26. Changed a few more instances of "const unsigned char *" to USPTR, making
556        the feature of a custom pointer more persuasive (as requested by a user).
557    
558    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
559        pcretest.c, inside #ifndefs, because it seems they are sometimes already
560        pre-defined.
561    
562    28. Added support for (*UTF8) at the start of a pattern.
563    
564    29. Arrange for flags added by the "release type" setting in CMake to be shown
565        in the configuration summary.
566    
567    
568    Version 7.8 05-Sep-08
569    ---------------------
570    
571    1.  Replaced UCP searching code with optimized version as implemented for Ad
572        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
573        stage table and inline lookup instead of a function, giving speed ups of 2
574        to 5 times on some simple patterns that I tested. Permission was given to
575        distribute the MultiStage2.py script that generates the tables (it's not in
576        the tarball, but is in the Subversion repository).
577    
578    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
579        scripts.
580    
581    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
582        a group with a zero qualifier. The result of the study could be incorrect,
583        or the function might crash, depending on the pattern.
584    
585    4.  Caseless matching was not working for non-ASCII characters in back
586        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
587        It now works when Unicode Property Support is available.
588    
589    5.  In pcretest, an escape such as \x{de} in the data was always generating
590        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
591        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
592        truncation.
593    
594    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
595    
596    7.  Added two (int) casts to pcregrep when printing the difference of two
597        pointers, in case they are 64-bit values.
598    
599    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
600        test 2 if it fails.
601    
602    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
603        and a #define of that name to empty if it is not externally set. This is to
604        allow users of MSVC to set it if necessary.
605    
606    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
607        the convenience functions in the pcre_get.c source file.
608    
609    11. An option change at the start of a pattern that had top-level alternatives
610        could cause overwriting and/or a crash. This command provoked a crash in
611        some environments:
612    
613          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
614    
615        This potential security problem was recorded as CVE-2008-2371.
616    
617    12. For a pattern where the match had to start at the beginning or immediately
618        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
619        pcre_dfa_exec() could read past the end of the passed subject if there was
620        no match. To help with detecting such bugs (e.g. with valgrind), I modified
621        pcretest so that it places the subject at the end of its malloc-ed buffer.
622    
623    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
624        exec() might read past the end of the data buffer in UTF-8 mode.
625    
626    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
627        the data contained the byte 0x85 as part of a UTF-8 character within its
628        first line. This applied both to normal and DFA matching.
629    
630    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
631        /^[^d]*?$/8 failed to match "abc".
632    
633    16. Added a missing copyright notice to pcrecpp_internal.h.
634    
635    17. Make it more clear in the documentation that values returned from
636        pcre_exec() in ovector are byte offsets, not character counts.
637    
638    18. Tidied a few places to stop certain compilers from issuing warnings.
639    
640    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
641        supplied by Stefan Weber. I made a further small update for 7.8 because
642        there is a change of source arrangements: the pcre_searchfuncs.c module is
643        replaced by pcre_ucd.c.
644    
645    
646    Version 7.7 07-May-08
647    ---------------------
648    
649    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
650        a string to a long long, pretend we don't even have a long long." This is
651        done by checking for the strtoq, strtoll, and _strtoi64 functions.
652    
653    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
654        pre-7.6 versions, which defined a global no_arg variable instead of putting
655        it in the RE class. (See also #8 below.)
656    
657    3.  Remove a line of dead code, identified by coverity and reported by Nuno
658        Lopes.
659    
660    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
661    
662        (1) The include/exclude patterns were being applied to the whole pathnames
663            of files, instead of just to the final components.
664    
665        (2) If there was more than one level of directory, the subdirectories were
666            skipped unless they satisfied the include/exclude conditions. This is
667            inconsistent with GNU grep (and could even be seen as contrary to the
668            pcregrep specification - which I improved to make it absolutely clear).
669            The action now is always to scan all levels of directory, and just
670            apply the include/exclude patterns to regular files.
671    
672    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
673        --exclude_dir in the tests to avoid scanning .svn directories.
674    
675    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
676        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
677        doesn't support NULs in patterns.
678    
679    7.  Added some missing "const"s to declarations of static tables in
680        pcre_compile.c and pcre_dfa_exec.c.
681    
682    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
683        caused by fix #2  above. (Subsequently also a second patch to fix the
684        first patch. And a third patch - this was a messy problem.)
685    
686    9.  Applied Craig's patch to remove the use of push_back().
687    
688    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
689        matching function regexec().
690    
691    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
692        which, however, unlike Perl's \g{...}, are subroutine calls, not back
693        references. PCRE supports relative numbers with this syntax (I don't think
694        Oniguruma does).
695    
696    12. Previously, a group with a zero repeat such as (...){0} was completely
697        omitted from the compiled regex. However, this means that if the group
698        was called as a subroutine from elsewhere in the pattern, things went wrong
699        (an internal error was given). Such groups are now left in the compiled
700        pattern, with a new opcode that causes them to be skipped at execution
701        time.
702    
703    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
704        to the way PCRE behaves:
705    
706        (a) A lone ] character is dis-allowed (Perl treats it as data).
707    
708        (b) A back reference to an unmatched subpattern matches an empty string
709            (Perl fails the current match path).
710    
711        (c) A data ] in a character class must be notated as \] because if the
712            first data character in a class is ], it defines an empty class. (In
713            Perl it is not possible to have an empty class.) The empty class []
714            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
715            The negative empty class [^] matches any one character, independently
716            of the DOTALL setting.
717    
718    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
719        non-existent subpattern following a character class starting with ']' and
720        containing () gave an internal compiling error instead of "reference to
721        non-existent subpattern". Fortunately, when the pattern did exist, the
722        compiled code was correct. (When scanning forwards to check for the
723        existencd of the subpattern, it was treating the data ']' as terminating
724        the class, so got the count wrong. When actually compiling, the reference
725        was subsequently set up correctly.)
726    
727    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
728        it was being rejected as not supported by pcre_dfa_exec(), even though
729        other assertions are supported. I have made pcre_dfa_exec() support
730        (*FAIL).
731    
732    16. The implementation of 13c above involved the invention of a new opcode,
733        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
734        cannot be changed at match time, I realized I could make a small
735        improvement to matching performance by compiling OP_ALLANY instead of
736        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
737        on the OP_ANY path.
738    
739    17. Compiling pcretest on Windows with readline support failed without the
740        following two fixes: (1) Make the unistd.h include conditional on
741        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
742    
743    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
744        ncurses library to be included for pcretest when ReadLine support is
745        requested, but also to allow for it to be overridden. This patch came from
746        Daniel Bergström.
747    
748    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
749        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
750        any errors with the current Unicode tables. Thanks to Peter Kankowski for
751        spotting this.
752    
753    
754    Version 7.6 28-Jan-08
755    ---------------------
756    
757    1.  A character class containing a very large number of characters with
758        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
759        overflow.
760    
761    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
762        HAVE_LONG_LONG is not defined.
763    
764    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
765        bring them up to date and include new features. This patch includes:
766    
767        - Fixed PH's badly added libz and libbz2 support.
768        - Fixed a problem with static linking.
769        - Added pcredemo. [But later removed - see 7 below.]
770        - Fixed dftables problem and added an option.
771        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
772            HAVE_LONG_LONG.
773        - Added readline support for pcretest.
774        - Added an listing of the option settings after cmake has run.
775    
776    4.  A user submitted a patch to Makefile that makes it easy to create
777        "pcre.dll" under mingw when using Configure/Make. I added stuff to
778        Makefile.am that cause it to include this special target, without
779        affecting anything else. Note that the same mingw target plus all
780        the other distribution libraries and programs are now supported
781        when configuring with CMake (see 6 below) instead of with
782        Configure/Make.
783    
784    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
785        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
786        exported in the Windows port". It has not yet been confirmed that the patch
787        solves the problem, but it does no harm.
788    
789    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
790        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
791        with CMake, and also correct the comment about stack recursion.
792    
793    7.  Remove the automatic building of pcredemo from the ./configure system and
794        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
795        of a program that users should build themselves after PCRE is installed, so
796        building it automatically is not really right. What is more, it gave
797        trouble in some build environments.
798    
799    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
800    
801    
802    Version 7.5 10-Jan-08
803    ---------------------
804    
805    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
806        values in parens when parsing an RE using the C++ wrapper."
807    
808    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
809        Characters greater than 255 were excluded from the class instead of being
810        included.
811    
812    3.  The same bug as (2) above applied to negated POSIX classes such as
813        [:^space:].
814    
815    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
816        defined or documented. It seems to have been a typo for PCRE_STATIC, so
817        I have changed it.
818    
819    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
820        first named subpattern) and a construct such as (?&a) would reference the
821        first named subpattern whose name started with "a" (in other words, the
822        length check was missing). Both these problems are fixed. "Subpattern name
823        expected" is now given for (?&) (a zero-length name), and this patch also
824        makes it give the same error for \k'' (previously it complained that that
825        was a reference to a non-existent subpattern).
826    
827    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
828        this is right because (?- can be followed by option settings as well as by
829        digits. I have, however, made the messages clearer.
830    
831    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
832        than the number used in the conditional) now cause a compile-time error.
833        This is actually not compatible with Perl, which accepts such patterns, but
834        treats the conditional as always being FALSE (as PCRE used to), but it
835        seems to me that giving a diagnostic is better.
836    
837    8.  Change "alphameric" to the more common word "alphanumeric" in comments
838        and messages.
839    
840    9.  Fix two occurrences of "backslash" in comments that should have been
841        "backspace".
842    
843    10. Remove two redundant lines of code that can never be obeyed (their function
844        was moved elsewhere).
845    
846    11. The program that makes PCRE's Unicode character property table had a bug
847        which caused it to generate incorrect table entries for sequences of
848        characters that have the same character type, but are in different scripts.
849        It amalgamated them into a single range, with the script of the first of
850        them. In other words, some characters were in the wrong script. There were
851        thirteen such cases, affecting characters in the following ranges:
852    
853          U+002b0 - U+002c1
854          U+0060c - U+0060d
855          U+0061e - U+00612
856          U+0064b - U+0065e
857          U+0074d - U+0076d
858          U+01800 - U+01805
859          U+01d00 - U+01d77
860          U+01d9b - U+01dbf
861          U+0200b - U+0200f
862          U+030fc - U+030fe
863          U+03260 - U+0327f
864          U+0fb46 - U+0fbb1
865          U+10450 - U+1049d
866    
867    12. The -o option (show only the matching part of a line) for pcregrep was not
868        compatible with GNU grep in that, if there was more than one match in a
869        line, it showed only the first of them. It now behaves in the same way as
870        GNU grep.
871    
872    13. If the -o and -v options were combined for pcregrep, it printed a blank
873        line for every non-matching line. GNU grep prints nothing, and pcregrep now
874        does the same. The return code can be used to tell if there were any
875        non-matching lines.
876    
877    14. Added --file-offsets and --line-offsets to pcregrep.
878    
879    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
880        infinitely looping recursion. The bug was that positive lookaheads were not
881        being skipped when checking for a possible empty match (negative lookaheads
882        and both kinds of lookbehind were skipped).
883    
884    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
885        inclusion of <windows.h> to before rather than after the definition of
886        INVALID_FILE_ATTRIBUTES (patch from David Byron).
887    
888    17. Specifying a possessive quantifier with a specific limit for a Unicode
889        character property caused pcre_compile() to compile bad code, which led at
890        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
891        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
892        caused the error; without that there was no problem.
893    
894    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
895    
896    19. Added --enable-pcretest-libreadline.
897    
898    20. In pcrecpp.cc, the variable 'count' was incremented twice in
899        RE::GlobalReplace(). As a result, the number of replacements returned was
900        double what it should be. I removed one of the increments, but Craig sent a
901        later patch that removed the other one (the right fix) and added unit tests
902        that check the return values (which was not done before).
903    
904    21. Several CMake things:
905    
906        (1) Arranged that, when cmake is used on Unix, the libraries end up with
907            the names libpcre and libpcreposix, not just pcre and pcreposix.
908    
909        (2) The above change means that pcretest and pcregrep are now correctly
910            linked with the newly-built libraries, not previously installed ones.
911    
912        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
913    
914    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
915        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
916        UTF-8 newline character). The key issue is that the pattern starts .*;
917        this means that the match must be either at the beginning, or after a
918        newline. The bug was in the code for advancing after a failed match and
919        checking that the new position followed a newline. It was not taking
920        account of UTF-8 characters correctly.
921    
922    23. PCRE was behaving differently from Perl in the way it recognized POSIX
923        character classes. PCRE was not treating the sequence [:...:] as a
924        character class unless the ... were all letters. Perl, however, seems to
925        allow any characters between [: and :], though of course it rejects as
926        unknown any "names" that contain non-letters, because all the known class
927        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
928        for example, whereas PCRE did not - it did not recognize a POSIX character
929        class. This seemed a bit dangerous, so the code has been changed to be
930        closer to Perl. The behaviour is not identical to Perl, because PCRE will
931        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
932        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
933        Perl does, and where it didn't before.
934    
935    24. Rewrite so as to remove the single use of %n from pcregrep because in some
936        Windows environments %n is disabled by default.
937    
938    
939    Version 7.4 21-Sep-07
940    ---------------------
941    
942    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
943        means that a class such as [\s] counted as "explicit reference to CR or
944        LF". That isn't really right - the whole point of the change was to try to
945        help when there was an actual mention of one of the two characters. So now
946        the change happens only if \r or \n (or a literal CR or LF) character is
947        encountered.
948    
949    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
950        of both had grown to the point where there were only 3 bits left.
951        Fortunately, there was spare space in the data structure, and so I have
952        moved the internal flags into a new 16-bit field to free up more option
953        bits.
954    
955    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
956        but did not set the internal JCHANGED flag - either of these is enough to
957        control the way the "get" function works - but the PCRE_INFO_JCHANGED
958        facility is supposed to tell if (?J) was ever used, so now (?J) at the
959        start sets both bits.
960    
961    4.  Added options (at build time, compile time, exec time) to change \R from
962        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
963    
964    5.  doc/pcresyntax.html was missing from the distribution.
965    
966    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
967        compatibility, even though it is no longer used.
968    
969    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
970        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
971        windows.h file is present (where different names are used). [This was
972        reversed later after testing - see 16 below.]
973    
974    8.  Changed all #include <config.h> to #include "config.h". There were also
975        some further <pcre.h> cases that I changed to "pcre.h".
976    
977    9.  When pcregrep was used with the --colour option, it missed the line ending
978        sequence off the lines that it output.
979    
980    10. It was pointed out to me that arrays of string pointers cause lots of
981        relocations when a shared library is dynamically loaded. A technique of
982        using a single long string with a table of offsets can drastically reduce
983        these. I have refactored PCRE in four places to do this. The result is
984        dramatic:
985    
986          Originally:                          290
987          After changing UCP table:            187
988          After changing error message table:   43
989          After changing table of "verbs"       36
990          After changing table of Posix names   22
991    
992        Thanks to the folks working on Gregex for glib for this insight.
993    
994    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
995        unicode-properties was also set.
996    
997    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
998    
999    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1000        checked only for CRLF.
1001    
1002    14. Added casts to pcretest.c to avoid compiler warnings.
1003    
1004    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1005    
1006    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1007        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1008        entirely. This removes changes made in 7 above.
1009    
1010    17. The CMake files have been updated, and there is now more information about
1011        building with CMake in the NON-UNIX-USE document.
1012    
1013    
1014    Version 7.3 28-Aug-07
1015  ---------------------  ---------------------
1016    
1017   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 9  Version 7.3 05-Jul-07 Line 1019  Version 7.3 05-Jul-07
1019      brackets there is not right, since it causes compilers to look for an      brackets there is not right, since it causes compilers to look for an
1020      installed pcre.h, not the version that is in the source that is being      installed pcre.h, not the version that is in the source that is being
1021      compiled (which of course may be different). I have changed it back to:      compiled (which of course may be different). I have changed it back to:
1022    
1023        #include "pcre.h"        #include "pcre.h"
1024    
1025      I have a vague recollection that the change was concerned with compiling in      I have a vague recollection that the change was concerned with compiling in
1026      different directories, but in the new build system, that is taken care of      different directories, but in the new build system, that is taken care of
1027      by the VPATH setting the Makefile.      by the VPATH setting the Makefile.
1028    
1029   2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed   2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1030      when the subject happened to end in the byte 0x85 (e.g. if the last      when the subject happened to end in the byte 0x85 (e.g. if the last
1031      character was \x{1ec5}). *Character* 0x85 is one of the "any" newline      character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
# Line 23  Version 7.3 05-Jul-07 Line 1033  Version 7.3 05-Jul-07
1033      of another character. The bug was that, for an unlimited repeat of . in      of another character. The bug was that, for an unlimited repeat of . in
1034      not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by      not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1035      characters when looking for a newline.      characters when looking for a newline.
   
  3. A small performance improvement in the DOTALL UTF-8 mode .* case.  
1036    
1037     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1038    
1039     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1040        in debug output.
1041    
1042     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1043        long printing in the pcrecpp unittest when running under MinGW.
1044    
1045     6. ESC_K was left out of the EBCDIC table.
1046    
1047     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1048        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1049        limit also applies to "virtual nesting" when a pattern is recursive, and in
1050        this case 1000 isn't so big. I have been able to remove this limit at the
1051        expense of backing off one optimization in certain circumstances. Normally,
1052        when pcre_exec() would call its internal match() function recursively and
1053        immediately return the result unconditionally, it uses a "tail recursion"
1054        feature to save stack. However, when a subpattern that can match an empty
1055        string has an unlimited repetition quantifier, it no longer makes this
1056        optimization. That gives it a stack frame in which to save the data for
1057        checking that an empty string has been matched. Previously this was taken
1058        from the 1000-entry workspace that had been reserved. So now there is no
1059        explicit limit, but more stack is used.
1060    
1061     8. Applied Daniel's patches to solve problems with the import/export magic
1062        syntax that is required for Windows, and which was going wrong for the
1063        pcreposix and pcrecpp parts of the library. These were overlooked when this
1064        problem was solved for the main library.
1065    
1066     9. There were some crude static tests to avoid integer overflow when computing
1067        the size of patterns that contain repeated groups with explicit upper
1068        limits. As the maximum quantifier is 65535, the maximum group length was
1069        set at 30,000 so that the product of these two numbers did not overflow a
1070        32-bit integer. However, it turns out that people want to use groups that
1071        are longer than 30,000 bytes (though not repeat them that many times).
1072        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1073        made it possible to implement the integer overflow checks in a much more
1074        dynamic way, which I have now done. The artificial limitation on group
1075        length has been removed - we now have only the limit on the total length of
1076        the compiled pattern, which depends on the LINK_SIZE setting.
1077    
1078    10. Fixed a bug in the documentation for get/copy named substring when
1079        duplicate names are permitted. If none of the named substrings are set, the
1080        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1081        empty string.
1082    
1083    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1084        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1085        because the ] is interpreted as the first data character and the
1086        terminating ] is not found. PCRE has been made compatible with Perl in this
1087        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1088        cause memory overwriting.
1089    
1090    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1091        string has been matched (to stop an infinite loop). It was not recognizing
1092        a conditional subpattern that could match an empty string if that
1093        subpattern was within another subpattern. For example, it looped when
1094        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1095        condition was not nested. This bug has been fixed.
1096    
1097    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1098        past the start of the subject in the presence of bytes with the top bit
1099        set, for example "\x8aBCD".
1100    
1101    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1102        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1103    
1104    14. Optimized (?!) to (*FAIL).
1105    
1106    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1107        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1108        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1109        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1110        does: it's just the validity check that is more restrictive.
1111    
1112    16. Inserted checks for integer overflows during escape sequence (backslash)
1113        processing, and also fixed erroneous offset values for syntax errors during
1114        backslash processing.
1115    
1116    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1117        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1118    
1119    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1120        caused an overrun.
1121    
1122    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1123        something other than just ASCII characters) inside a group that had an
1124        unlimited repeat caused a loop at compile time (while checking to see
1125        whether the group could match an empty string).
1126    
1127    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1128        [\P{Any}] did so. (Error in the code for printing property names.)
1129    
1130    21. An orphan \E inside a character class could cause a crash.
1131    
1132    22. A repeated capturing bracket such as (A)? could cause a wild memory
1133        reference during compilation.
1134    
1135    23. There are several functions in pcre_compile() that scan along a compiled
1136        expression for various reasons (e.g. to see if it's fixed length for look
1137        behind). There were bugs in these functions when a repeated \p or \P was
1138        present in the pattern. These operators have additional parameters compared
1139        with \d, etc, and these were not being taken into account when moving along
1140        the compiled data. Specifically:
1141    
1142        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1143            length.
1144    
1145        (b) An item such as \pL+ within a repeated group could cause crashes or
1146            loops.
1147    
1148        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1149            "reference to non-existent subpattern" error.
1150    
1151        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1152    
1153    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1154        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1155    
1156    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1157    
1158    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1159        character were causing crashes (broken optimization).
1160    
1161    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1162        \p or \P) caused a compile-time loop.
1163    
1164    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1165        break. For example, the unstudied pattern [\r\n]A does not match the string
1166        "\r\nA" because change 7.0/46 below moves the current point on by two
1167        characters after failing to match at the start. However, the pattern \nA
1168        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1169        the same is true. There doesn't seem any very clean way out of this, but
1170        what I have chosen to do makes the common cases work: PCRE now takes note
1171        of whether there can be an explicit match for \r or \n anywhere in the
1172        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1173        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1174        pattern has explicit CR or LF references.
1175    
1176    29. Added (*CR) etc for changing newline setting at start of pattern.
1177    
1178    
1179  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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