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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 05-Jul-07  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    
48    Version 8.02 19-Mar-2010
49    ------------------------
50    
51    1.  The Unicode data tables have been updated to Unicode 5.2.0.
52    
53    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
54        configured.
55    
56    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
57        original author of that file, following a query about its status.
58    
59    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
60        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
61    
62    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
63        quantifier applied to a forward-referencing subroutine call, could compile
64        incorrect code or give the error "internal error: previously-checked
65        referenced subpattern not found".
66    
67    6.  Both MS Visual Studio and Symbian OS have problems with initializing
68        variables to point to external functions. For these systems, therefore,
69        pcre_malloc etc. are now initialized to local functions that call the
70        relevant global functions.
71    
72    7.  There were two entries missing in the vectors called coptable and poptable
73        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
74        I've fixed the data, and added a kludgy way of testing at compile time that
75        the lengths are correct (equal to the number of opcodes).
76    
77    8.  Following on from 7, I added a similar kludge to check the length of the
78        eint vector in pcreposix.c.
79    
80    9.  Error texts for pcre_compile() are held as one long string to avoid too
81        much relocation at load time. To find a text, the string is searched,
82        counting zeros. There was no check for running off the end of the string,
83        which could happen if a new error number was added without updating the
84        string.
85    
86    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
87    
88    11. \K was not working if it appeared in an atomic group or in a group that
89        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
90        \K is "not well defined" if used in an assertion. PCRE now accepts it if
91        the assertion is positive, but not if it is negative.
92    
93    12. Change 11 fortuitously reduced the size of the stack frame used in the
94        "match()" function of pcre_exec.c by one pointer. Forthcoming
95        implementation of support for (*MARK) will need an extra pointer on the
96        stack; I have reserved it now, so that the stack frame size does not
97        decrease.
98    
99    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
100        item in branch that calls a recursion is a subroutine call - as in the
101        second branch in the above example - was incorrectly given the compile-
102        time error "recursive call could loop indefinitely" because pcre_compile()
103        was not correctly checking the subroutine for matching a non-empty string.
104    
105    14. The checks for overrunning compiling workspace could trigger after an
106        overrun had occurred. This is a "should never occur" error, but it can be
107        triggered by pathological patterns such as hundreds of nested parentheses.
108        The checks now trigger 100 bytes before the end of the workspace.
109    
110    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
111    
112    
113    Version 8.01 19-Jan-2010
114    ------------------------
115    
116    1.  If a pattern contained a conditional subpattern with only one branch (in
117        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
118        computed the wrong minimum data length (which is of course zero for such
119        subpatterns). This could cause incorrect "no match" results.
120    
121    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
122        the pattern is reset in the first branch, pcre_compile() failed with
123        "internal error: code overflow at offset...". This happened only when
124        the reset was to the original external option setting. (An optimization
125        abstracts leading options settings into an external setting, which was the
126        cause of this.)
127    
128    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
129        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
130        assertion pattern did not match (meaning that the assertion was true), it
131        was incorrectly treated as false if the SKIP had been reached during the
132        matching. This also applied to assertions used as conditions.
133    
134    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
135        assertion subpattern, including such a pattern used as a condition,
136        unpredictable results occurred, instead of the error return
137        PCRE_ERROR_DFA_UITEM.
138    
139    5.  The C++ GlobalReplace function was not working like Perl for the special
140        situation when an empty string is matched. It now does the fancy magic
141        stuff that is necessary.
142    
143    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
144        removed. (These were left over from very, very early versions of PCRE.)
145    
146    7.  Some cosmetic changes to the code to make life easier when compiling it
147        as part of something else:
148    
149        (a) Change DEBUG to PCRE_DEBUG.
150    
151        (b) In pcre_compile(), rename the member of the "branch_chain" structure
152            called "current" as "current_branch", to prevent a collision with the
153            Linux macro when compiled as a kernel module.
154    
155        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
156            prevent a collision with the Linux macro when compiled as a kernel
157            module.
158    
159    8.  In pcre_compile() there are some checks for integer overflows that used to
160        cast potentially large values to (double). This has been changed to that
161        when building, a check for int64_t is made, and if it is found, it is used
162        instead, thus avoiding the use of floating point arithmetic. (There is no
163        other use of FP in PCRE.) If int64_t is not found, the fallback is to
164        double.
165    
166    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
167        2005 (difference between two addresses compared to an unsigned value).
168    
169    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
170        custom one, because of the following reported problem in Windows:
171    
172          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
173              under Win32.
174          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
175              therefore missing the function definition.
176          - The compiler thus generates a "C" signature for the test function.
177          - The linker fails to find the "C" function.
178          - PCRE fails to configure if asked to do so against libbz2.
179    
180    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
181        messages were output:
182    
183          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
184          rerunning libtoolize, to keep the correct libtool macros in-tree.
185          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
186    
187        I have done both of these things.
188    
189    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
190        most of the time, it *can* run out if it is given a pattern that contains a
191        runaway infinite recursion. I updated the discussion in the pcrestack man
192        page.
193    
194    13. Now that we have gone to the x.xx style of version numbers, the minor
195        version may start with zero. Using 08 or 09 is a bad idea because users
196        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
197        interpreted as invalid octal numbers. I've updated the previous comment in
198        configure.ac, and also added a check that gives an error if 08 or 09 are
199        used.
200    
201    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
202        causing partial matching to fail when the end of the subject matched \W
203        in a UTF-8 pattern where \W was quantified with a minimum of 3.
204    
205    15. There were some discrepancies between the declarations in pcre_internal.h
206        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
207        their definitions. The declarations used "const uschar *" and the
208        definitions used USPTR. Even though USPTR is normally defined as "const
209        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
210        reported that: "This difference in casting confuses some C++ compilers, for
211        example, SunCC recognizes above declarations as different functions and
212        generates broken code for hbpcre." I have changed the declarations to use
213        USPTR.
214    
215    16. GNU libtool is named differently on some systems. The autogen.sh script now
216        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
217        (FreeBSD).
218    
219    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
220        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
221        comment: "Figure out how to create a longlong from a string: strtoll and
222        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
223        instance, but it only takes 2 args instead of 3!"
224    
225    18. A subtle bug concerned with back references has been fixed by a change of
226        specification, with a corresponding code fix. A pattern such as
227        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
228        refers, was giving matches when it shouldn't. For example, xa=xaaa would
229        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
230        same bug. Such groups have to be quantified to be useful, or contained
231        inside another quantified group. (If there's no repetition, the reference
232        can never match.) The problem arises because, having left the group and
233        moved on to the rest of the pattern, a later failure that backtracks into
234        the group uses the captured value from the final iteration of the group
235        rather than the correct earlier one. I have fixed this in PCRE by forcing
236        any group that contains a reference to itself to be an atomic group; that
237        is, there cannot be any backtracking into it once it has completed. This is
238        similar to recursive and subroutine calls.
239    
240    
241    Version 8.00 19-Oct-09
242    ----------------------
243    
244    1.  The table for translating pcre_compile() error codes into POSIX error codes
245        was out-of-date, and there was no check on the pcre_compile() error code
246        being within the table. This could lead to an OK return being given in
247        error.
248    
249    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
250        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
251        in a Windows environment.
252    
253    3.  The pcregrep --count option prints the count for each file even when it is
254        zero, as does GNU grep. However, pcregrep was also printing all files when
255        --files-with-matches was added. Now, when both options are given, it prints
256        counts only for those files that have at least one match. (GNU grep just
257        prints the file name in this circumstance, but including the count seems
258        more useful - otherwise, why use --count?) Also ensured that the
259        combination -clh just lists non-zero counts, with no names.
260    
261    4.  The long form of the pcregrep -F option was incorrectly implemented as
262        --fixed_strings instead of --fixed-strings. This is an incompatible change,
263        but it seems right to fix it, and I didn't think it was worth preserving
264        the old behaviour.
265    
266    5.  The command line items --regex=pattern and --regexp=pattern were not
267        recognized by pcregrep, which required --regex pattern or --regexp pattern
268        (with a space rather than an '='). The man page documented the '=' forms,
269        which are compatible with GNU grep; these now work.
270    
271    6.  No libpcreposix.pc file was created for pkg-config; there was just
272        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
273    
274    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
275        when UCP support is not needed, by modifying the Python script that
276        generates it from Unicode data files. This should not matter if the module
277        is correctly used as a library, but I received one complaint about 50K of
278        unwanted data. My guess is that the person linked everything into his
279        program rather than using a library. Anyway, it does no harm.
280    
281    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
282        was a minimum greater than 1 for a wide character in a possessive
283        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
284        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
285        character. Chaos in the form of incorrect output or a compiling loop could
286        result.
287    
288    9.  The restrictions on what a pattern can contain when partial matching is
289        requested for pcre_exec() have been removed. All patterns can now be
290        partially matched by this function. In addition, if there are at least two
291        slots in the offset vector, the offset of the earliest inspected character
292        for the match and the offset of the end of the subject are set in them when
293        PCRE_ERROR_PARTIAL is returned.
294    
295    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
296        synonymous with PCRE_PARTIAL, for backwards compatibility, and
297        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
298        and may be more useful for multi-segment matching.
299    
300    11. Partial matching with pcre_exec() is now more intuitive. A partial match
301        used to be given if ever the end of the subject was reached; now it is
302        given only if matching could not proceed because another character was
303        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
304        string "Z", which now yields "no match" instead of "partial match". In the
305        case of pcre_dfa_exec(), "no match" is given if every matching path for the
306        final character ended with (*FAIL).
307    
308    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
309        if the pattern had a "must contain" character that was already found in the
310        earlier partial match, unless partial matching was again requested. For
311        example, with the pattern /dog.(body)?/, the "must contain" character is
312        "g". If the first part-match was for the string "dog", restarting with
313        "sbody" failed. This bug has been fixed.
314    
315    13. The string returned by pcre_dfa_exec() after a partial match has been
316        changed so that it starts at the first inspected character rather than the
317        first character of the match. This makes a difference only if the pattern
318        starts with a lookbehind assertion or \b or \B (\K is not supported by
319        pcre_dfa_exec()). It's an incompatible change, but it makes the two
320        matching functions compatible, and I think it's the right thing to do.
321    
322    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
323        so that the demonstration program is easily available in environments where
324        PCRE has not been installed from source.
325    
326    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
327        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
328        library.
329    
330    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
331        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
332        is not the first non-POSIX option to be added. Clearly some people find
333        these options useful.
334    
335    17. If a caller to the POSIX matching function regexec() passes a non-zero
336        value for nmatch with a NULL value for pmatch, the value of
337        nmatch is forced to zero.
338    
339    18. RunGrepTest did not have a test for the availability of the -u option of
340        the diff command, as RunTest does. It now checks in the same way as
341        RunTest, and also checks for the -b option.
342    
343    19. If an odd number of negated classes containing just a single character
344        interposed, within parentheses, between a forward reference to a named
345        subpattern and the definition of the subpattern, compilation crashed with
346        an internal error, complaining that it could not find the referenced
347        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
348        [The bug was that it was starting one character too far in when skipping
349        over the character class, thus treating the ] as data rather than
350        terminating the class. This meant it could skip too much.]
351    
352    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
353        /g option in pcretest when the pattern contains \K, which makes it possible
354        to have an empty string match not at the start, even when the pattern is
355        anchored. Updated pcretest and pcredemo to use this option.
356    
357    21. If the maximum number of capturing subpatterns in a recursion was greater
358        than the maximum at the outer level, the higher number was returned, but
359        with unset values at the outer level. The correct (outer level) value is
360        now given.
361    
362    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
363        PCRE did not set those parentheses (unlike Perl). I have now found a way to
364        make it do so. The string so far is captured, making this feature
365        compatible with Perl.
366    
367    23. The tests have been re-organized, adding tests 11 and 12, to make it
368        possible to check the Perl 5.10 features against Perl 5.10.
369    
370    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
371        pattern matches a fixed length string. PCRE did not allow this; now it
372        does. Neither allows recursion.
373    
374    25. I finally figured out how to implement a request to provide the minimum
375        length of subject string that was needed in order to match a given pattern.
376        (It was back references and recursion that I had previously got hung up
377        on.) This code has now been added to pcre_study(); it finds a lower bound
378        to the length of subject needed. It is not necessarily the greatest lower
379        bound, but using it to avoid searching strings that are too short does give
380        some useful speed-ups. The value is available to calling programs via
381        pcre_fullinfo().
382    
383    26. While implementing 25, I discovered to my embarrassment that pcretest had
384        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
385        study optimizations had never been tested with that matching function.
386        Oops. What is worse, even when it was passed study data, there was a bug in
387        pcre_dfa_exec() that meant it never actually used it. Double oops. There
388        were also very few tests of studied patterns with pcre_dfa_exec().
389    
390    27. If (?| is used to create subpatterns with duplicate numbers, they are now
391        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
392        on the other side of the coin, they are no longer allowed to have different
393        names, because these cannot be distinguished in PCRE, and this has caused
394        confusion. (This is a difference from Perl.)
395    
396    28. When duplicate subpattern names are present (necessarily with different
397        numbers, as required by 27 above), and a test is made by name in a
398        conditional pattern, either for a subpattern having been matched, or for
399        recursion in such a pattern, all the associated numbered subpatterns are
400        tested, and the overall condition is true if the condition is true for any
401        one of them. This is the way Perl works, and is also more like the way
402        testing by number works.
403    
404    
405    Version 7.9 11-Apr-09
406    ---------------------
407    
408    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
409        (pcretest), all targets were linked against these libraries. This included
410        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
411        libraries. This caused unwanted dependencies to be created. This problem
412        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
413        pcretest is linked with readline.
414    
415    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
416        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
417        moved outside it again, because FALSE and TRUE are already defined in AIX,
418        but BOOL is not.
419    
420    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
421        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
422    
423    4.  The pcregrep documentation said spaces were inserted as well as colons (or
424        hyphens) following file names and line numbers when outputting matching
425        lines. This is not true; no spaces are inserted. I have also clarified the
426        wording for the --colour (or --color) option.
427    
428    5.  In pcregrep, when --colour was used with -o, the list of matching strings
429        was not coloured; this is different to GNU grep, so I have changed it to be
430        the same.
431    
432    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
433        each matching line was coloured. Now it goes on to look for further matches
434        of any of the test patterns, which is the same behaviour as GNU grep.
435    
436    7.  A pattern that could match an empty string could cause pcregrep to loop; it
437        doesn't make sense to accept an empty string match in pcregrep, so I have
438        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
439        seems to be how GNU grep behaves.
440    
441    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
442        start or after a newline", because the conditional assertion was not being
443        correctly handled. The rule now is that both the assertion and what follows
444        in the first alternative must satisfy the test.
445    
446    9.  If auto-callout was enabled in a pattern with a conditional group whose
447        condition was an assertion, PCRE could crash during matching, both with
448        pcre_exec() and pcre_dfa_exec().
449    
450    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
451        used for matching.
452    
453    11. Unicode property support in character classes was not working for
454        characters (bytes) greater than 127 when not in UTF-8 mode.
455    
456    12. Added the -M command line option to pcretest.
457    
458    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
459    
460    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
461    
462    16. Added comments and documentation about mis-use of no_arg in the C++
463        wrapper.
464    
465    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
466        from Martin Jerabek that uses macro names for all relevant character and
467        string constants.
468    
469    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
470        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
471        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
472        these, but not everybody uses configure.
473    
474    19. A conditional group that had only one branch was not being correctly
475        recognized as an item that could match an empty string. This meant that an
476        enclosing group might also not be so recognized, causing infinite looping
477        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
478        with the subject "ab", where knowledge that the repeated group can match
479        nothing is needed in order to break the loop.
480    
481    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
482        exec(), but without supplying a callout function, matching went wrong.
483    
484    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
485        leak if the size of the offset vector was greater than 30. When the vector
486        is smaller, the saved offsets during recursion go onto a local stack
487        vector, but for larger vectors malloc() is used. It was failing to free
488        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
489        error, in fact).
490    
491    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
492        heapframe that is used only when UTF-8 support is enabled. This caused no
493        problem, but was untidy.
494    
495    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
496        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
497        included within another project.
498    
499    24. Steven Van Ingelgem's patches to add more options to the CMake support,
500        slightly modified by me:
501    
502          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
503              not building pcregrep.
504    
505          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
506              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
507    
508    25. Forward references, both numeric and by name, in patterns that made use of
509        duplicate group numbers, could behave incorrectly or give incorrect errors,
510        because when scanning forward to find the reference group, PCRE was not
511        taking into account the duplicate group numbers. A pattern such as
512        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
513    
514    26. Changed a few more instances of "const unsigned char *" to USPTR, making
515        the feature of a custom pointer more persuasive (as requested by a user).
516    
517    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
518        pcretest.c, inside #ifndefs, because it seems they are sometimes already
519        pre-defined.
520    
521    28. Added support for (*UTF8) at the start of a pattern.
522    
523    29. Arrange for flags added by the "release type" setting in CMake to be shown
524        in the configuration summary.
525    
526    
527    Version 7.8 05-Sep-08
528    ---------------------
529    
530    1.  Replaced UCP searching code with optimized version as implemented for Ad
531        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
532        stage table and inline lookup instead of a function, giving speed ups of 2
533        to 5 times on some simple patterns that I tested. Permission was given to
534        distribute the MultiStage2.py script that generates the tables (it's not in
535        the tarball, but is in the Subversion repository).
536    
537    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
538        scripts.
539    
540    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
541        a group with a zero qualifier. The result of the study could be incorrect,
542        or the function might crash, depending on the pattern.
543    
544    4.  Caseless matching was not working for non-ASCII characters in back
545        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
546        It now works when Unicode Property Support is available.
547    
548    5.  In pcretest, an escape such as \x{de} in the data was always generating
549        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
550        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
551        truncation.
552    
553    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
554    
555    7.  Added two (int) casts to pcregrep when printing the difference of two
556        pointers, in case they are 64-bit values.
557    
558    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
559        test 2 if it fails.
560    
561    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
562        and a #define of that name to empty if it is not externally set. This is to
563        allow users of MSVC to set it if necessary.
564    
565    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
566        the convenience functions in the pcre_get.c source file.
567    
568    11. An option change at the start of a pattern that had top-level alternatives
569        could cause overwriting and/or a crash. This command provoked a crash in
570        some environments:
571    
572          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
573    
574        This potential security problem was recorded as CVE-2008-2371.
575    
576    12. For a pattern where the match had to start at the beginning or immediately
577        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
578        pcre_dfa_exec() could read past the end of the passed subject if there was
579        no match. To help with detecting such bugs (e.g. with valgrind), I modified
580        pcretest so that it places the subject at the end of its malloc-ed buffer.
581    
582    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
583        exec() might read past the end of the data buffer in UTF-8 mode.
584    
585    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
586        the data contained the byte 0x85 as part of a UTF-8 character within its
587        first line. This applied both to normal and DFA matching.
588    
589    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
590        /^[^d]*?$/8 failed to match "abc".
591    
592    16. Added a missing copyright notice to pcrecpp_internal.h.
593    
594    17. Make it more clear in the documentation that values returned from
595        pcre_exec() in ovector are byte offsets, not character counts.
596    
597    18. Tidied a few places to stop certain compilers from issuing warnings.
598    
599    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
600        supplied by Stefan Weber. I made a further small update for 7.8 because
601        there is a change of source arrangements: the pcre_searchfuncs.c module is
602        replaced by pcre_ucd.c.
603    
604    
605    Version 7.7 07-May-08
606    ---------------------
607    
608    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
609        a string to a long long, pretend we don't even have a long long." This is
610        done by checking for the strtoq, strtoll, and _strtoi64 functions.
611    
612    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
613        pre-7.6 versions, which defined a global no_arg variable instead of putting
614        it in the RE class. (See also #8 below.)
615    
616    3.  Remove a line of dead code, identified by coverity and reported by Nuno
617        Lopes.
618    
619    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
620    
621        (1) The include/exclude patterns were being applied to the whole pathnames
622            of files, instead of just to the final components.
623    
624        (2) If there was more than one level of directory, the subdirectories were
625            skipped unless they satisfied the include/exclude conditions. This is
626            inconsistent with GNU grep (and could even be seen as contrary to the
627            pcregrep specification - which I improved to make it absolutely clear).
628            The action now is always to scan all levels of directory, and just
629            apply the include/exclude patterns to regular files.
630    
631    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
632        --exclude_dir in the tests to avoid scanning .svn directories.
633    
634    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
635        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
636        doesn't support NULs in patterns.
637    
638    7.  Added some missing "const"s to declarations of static tables in
639        pcre_compile.c and pcre_dfa_exec.c.
640    
641    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
642        caused by fix #2  above. (Subsequently also a second patch to fix the
643        first patch. And a third patch - this was a messy problem.)
644    
645    9.  Applied Craig's patch to remove the use of push_back().
646    
647    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
648        matching function regexec().
649    
650    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
651        which, however, unlike Perl's \g{...}, are subroutine calls, not back
652        references. PCRE supports relative numbers with this syntax (I don't think
653        Oniguruma does).
654    
655    12. Previously, a group with a zero repeat such as (...){0} was completely
656        omitted from the compiled regex. However, this means that if the group
657        was called as a subroutine from elsewhere in the pattern, things went wrong
658        (an internal error was given). Such groups are now left in the compiled
659        pattern, with a new opcode that causes them to be skipped at execution
660        time.
661    
662    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
663        to the way PCRE behaves:
664    
665        (a) A lone ] character is dis-allowed (Perl treats it as data).
666    
667        (b) A back reference to an unmatched subpattern matches an empty string
668            (Perl fails the current match path).
669    
670        (c) A data ] in a character class must be notated as \] because if the
671            first data character in a class is ], it defines an empty class. (In
672            Perl it is not possible to have an empty class.) The empty class []
673            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
674            The negative empty class [^] matches any one character, independently
675            of the DOTALL setting.
676    
677    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
678        non-existent subpattern following a character class starting with ']' and
679        containing () gave an internal compiling error instead of "reference to
680        non-existent subpattern". Fortunately, when the pattern did exist, the
681        compiled code was correct. (When scanning forwards to check for the
682        existencd of the subpattern, it was treating the data ']' as terminating
683        the class, so got the count wrong. When actually compiling, the reference
684        was subsequently set up correctly.)
685    
686    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
687        it was being rejected as not supported by pcre_dfa_exec(), even though
688        other assertions are supported. I have made pcre_dfa_exec() support
689        (*FAIL).
690    
691    16. The implementation of 13c above involved the invention of a new opcode,
692        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
693        cannot be changed at match time, I realized I could make a small
694        improvement to matching performance by compiling OP_ALLANY instead of
695        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
696        on the OP_ANY path.
697    
698    17. Compiling pcretest on Windows with readline support failed without the
699        following two fixes: (1) Make the unistd.h include conditional on
700        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
701    
702    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
703        ncurses library to be included for pcretest when ReadLine support is
704        requested, but also to allow for it to be overridden. This patch came from
705        Daniel Bergström.
706    
707    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
708        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
709        any errors with the current Unicode tables. Thanks to Peter Kankowski for
710        spotting this.
711    
712    
713    Version 7.6 28-Jan-08
714    ---------------------
715    
716    1.  A character class containing a very large number of characters with
717        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
718        overflow.
719    
720    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
721        HAVE_LONG_LONG is not defined.
722    
723    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
724        bring them up to date and include new features. This patch includes:
725    
726        - Fixed PH's badly added libz and libbz2 support.
727        - Fixed a problem with static linking.
728        - Added pcredemo. [But later removed - see 7 below.]
729        - Fixed dftables problem and added an option.
730        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
731            HAVE_LONG_LONG.
732        - Added readline support for pcretest.
733        - Added an listing of the option settings after cmake has run.
734    
735    4.  A user submitted a patch to Makefile that makes it easy to create
736        "pcre.dll" under mingw when using Configure/Make. I added stuff to
737        Makefile.am that cause it to include this special target, without
738        affecting anything else. Note that the same mingw target plus all
739        the other distribution libraries and programs are now supported
740        when configuring with CMake (see 6 below) instead of with
741        Configure/Make.
742    
743    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
744        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
745        exported in the Windows port". It has not yet been confirmed that the patch
746        solves the problem, but it does no harm.
747    
748    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
749        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
750        with CMake, and also correct the comment about stack recursion.
751    
752    7.  Remove the automatic building of pcredemo from the ./configure system and
753        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
754        of a program that users should build themselves after PCRE is installed, so
755        building it automatically is not really right. What is more, it gave
756        trouble in some build environments.
757    
758    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
759    
760    
761    Version 7.5 10-Jan-08
762    ---------------------
763    
764    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
765        values in parens when parsing an RE using the C++ wrapper."
766    
767    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
768        Characters greater than 255 were excluded from the class instead of being
769        included.
770    
771    3.  The same bug as (2) above applied to negated POSIX classes such as
772        [:^space:].
773    
774    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
775        defined or documented. It seems to have been a typo for PCRE_STATIC, so
776        I have changed it.
777    
778    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
779        first named subpattern) and a construct such as (?&a) would reference the
780        first named subpattern whose name started with "a" (in other words, the
781        length check was missing). Both these problems are fixed. "Subpattern name
782        expected" is now given for (?&) (a zero-length name), and this patch also
783        makes it give the same error for \k'' (previously it complained that that
784        was a reference to a non-existent subpattern).
785    
786    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
787        this is right because (?- can be followed by option settings as well as by
788        digits. I have, however, made the messages clearer.
789    
790    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
791        than the number used in the conditional) now cause a compile-time error.
792        This is actually not compatible with Perl, which accepts such patterns, but
793        treats the conditional as always being FALSE (as PCRE used to), but it
794        seems to me that giving a diagnostic is better.
795    
796    8.  Change "alphameric" to the more common word "alphanumeric" in comments
797        and messages.
798    
799    9.  Fix two occurrences of "backslash" in comments that should have been
800        "backspace".
801    
802    10. Remove two redundant lines of code that can never be obeyed (their function
803        was moved elsewhere).
804    
805    11. The program that makes PCRE's Unicode character property table had a bug
806        which caused it to generate incorrect table entries for sequences of
807        characters that have the same character type, but are in different scripts.
808        It amalgamated them into a single range, with the script of the first of
809        them. In other words, some characters were in the wrong script. There were
810        thirteen such cases, affecting characters in the following ranges:
811    
812          U+002b0 - U+002c1
813          U+0060c - U+0060d
814          U+0061e - U+00612
815          U+0064b - U+0065e
816          U+0074d - U+0076d
817          U+01800 - U+01805
818          U+01d00 - U+01d77
819          U+01d9b - U+01dbf
820          U+0200b - U+0200f
821          U+030fc - U+030fe
822          U+03260 - U+0327f
823          U+0fb46 - U+0fbb1
824          U+10450 - U+1049d
825    
826    12. The -o option (show only the matching part of a line) for pcregrep was not
827        compatible with GNU grep in that, if there was more than one match in a
828        line, it showed only the first of them. It now behaves in the same way as
829        GNU grep.
830    
831    13. If the -o and -v options were combined for pcregrep, it printed a blank
832        line for every non-matching line. GNU grep prints nothing, and pcregrep now
833        does the same. The return code can be used to tell if there were any
834        non-matching lines.
835    
836    14. Added --file-offsets and --line-offsets to pcregrep.
837    
838    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
839        infinitely looping recursion. The bug was that positive lookaheads were not
840        being skipped when checking for a possible empty match (negative lookaheads
841        and both kinds of lookbehind were skipped).
842    
843    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
844        inclusion of <windows.h> to before rather than after the definition of
845        INVALID_FILE_ATTRIBUTES (patch from David Byron).
846    
847    17. Specifying a possessive quantifier with a specific limit for a Unicode
848        character property caused pcre_compile() to compile bad code, which led at
849        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
850        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
851        caused the error; without that there was no problem.
852    
853    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
854    
855    19. Added --enable-pcretest-libreadline.
856    
857    20. In pcrecpp.cc, the variable 'count' was incremented twice in
858        RE::GlobalReplace(). As a result, the number of replacements returned was
859        double what it should be. I removed one of the increments, but Craig sent a
860        later patch that removed the other one (the right fix) and added unit tests
861        that check the return values (which was not done before).
862    
863    21. Several CMake things:
864    
865        (1) Arranged that, when cmake is used on Unix, the libraries end up with
866            the names libpcre and libpcreposix, not just pcre and pcreposix.
867    
868        (2) The above change means that pcretest and pcregrep are now correctly
869            linked with the newly-built libraries, not previously installed ones.
870    
871        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
872    
873    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
874        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
875        UTF-8 newline character). The key issue is that the pattern starts .*;
876        this means that the match must be either at the beginning, or after a
877        newline. The bug was in the code for advancing after a failed match and
878        checking that the new position followed a newline. It was not taking
879        account of UTF-8 characters correctly.
880    
881    23. PCRE was behaving differently from Perl in the way it recognized POSIX
882        character classes. PCRE was not treating the sequence [:...:] as a
883        character class unless the ... were all letters. Perl, however, seems to
884        allow any characters between [: and :], though of course it rejects as
885        unknown any "names" that contain non-letters, because all the known class
886        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
887        for example, whereas PCRE did not - it did not recognize a POSIX character
888        class. This seemed a bit dangerous, so the code has been changed to be
889        closer to Perl. The behaviour is not identical to Perl, because PCRE will
890        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
891        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
892        Perl does, and where it didn't before.
893    
894    24. Rewrite so as to remove the single use of %n from pcregrep because in some
895        Windows environments %n is disabled by default.
896    
897    
898    Version 7.4 21-Sep-07
899    ---------------------
900    
901    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
902        means that a class such as [\s] counted as "explicit reference to CR or
903        LF". That isn't really right - the whole point of the change was to try to
904        help when there was an actual mention of one of the two characters. So now
905        the change happens only if \r or \n (or a literal CR or LF) character is
906        encountered.
907    
908    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
909        of both had grown to the point where there were only 3 bits left.
910        Fortunately, there was spare space in the data structure, and so I have
911        moved the internal flags into a new 16-bit field to free up more option
912        bits.
913    
914    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
915        but did not set the internal JCHANGED flag - either of these is enough to
916        control the way the "get" function works - but the PCRE_INFO_JCHANGED
917        facility is supposed to tell if (?J) was ever used, so now (?J) at the
918        start sets both bits.
919    
920    4.  Added options (at build time, compile time, exec time) to change \R from
921        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
922    
923    5.  doc/pcresyntax.html was missing from the distribution.
924    
925    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
926        compatibility, even though it is no longer used.
927    
928    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
929        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
930        windows.h file is present (where different names are used). [This was
931        reversed later after testing - see 16 below.]
932    
933    8.  Changed all #include <config.h> to #include "config.h". There were also
934        some further <pcre.h> cases that I changed to "pcre.h".
935    
936    9.  When pcregrep was used with the --colour option, it missed the line ending
937        sequence off the lines that it output.
938    
939    10. It was pointed out to me that arrays of string pointers cause lots of
940        relocations when a shared library is dynamically loaded. A technique of
941        using a single long string with a table of offsets can drastically reduce
942        these. I have refactored PCRE in four places to do this. The result is
943        dramatic:
944    
945          Originally:                          290
946          After changing UCP table:            187
947          After changing error message table:   43
948          After changing table of "verbs"       36
949          After changing table of Posix names   22
950    
951        Thanks to the folks working on Gregex for glib for this insight.
952    
953    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
954        unicode-properties was also set.
955    
956    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
957    
958    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
959        checked only for CRLF.
960    
961    14. Added casts to pcretest.c to avoid compiler warnings.
962    
963    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
964    
965    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
966        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
967        entirely. This removes changes made in 7 above.
968    
969    17. The CMake files have been updated, and there is now more information about
970        building with CMake in the NON-UNIX-USE document.
971    
972    
973    Version 7.3 28-Aug-07
974  ---------------------  ---------------------
975    
976   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 978  Version 7.3 05-Jul-07
978      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
979      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
980      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:
981    
982        #include "pcre.h"        #include "pcre.h"
   
     I have a vague recollection that the change was concerned with compiling in  
     different directories, but in the new build system, that is taken care of  
     by the VPATH setting the Makefile.  
983    
984        I have a vague recollection that the change was concerned with compiling in
985        different directories, but in the new build system, that is taken care of
986        by the VPATH setting the Makefile.
987    
988     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
989        when the subject happened to end in the byte 0x85 (e.g. if the last
990        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
991        characters but of course it shouldn't be taken as a newline when it is part
992        of another character. The bug was that, for an unlimited repeat of . in
993        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
994        characters when looking for a newline.
995    
996     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
997    
998     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
999        in debug output.
1000    
1001     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1002        long printing in the pcrecpp unittest when running under MinGW.
1003    
1004     6. ESC_K was left out of the EBCDIC table.
1005    
1006     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1007        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1008        limit also applies to "virtual nesting" when a pattern is recursive, and in
1009        this case 1000 isn't so big. I have been able to remove this limit at the
1010        expense of backing off one optimization in certain circumstances. Normally,
1011        when pcre_exec() would call its internal match() function recursively and
1012        immediately return the result unconditionally, it uses a "tail recursion"
1013        feature to save stack. However, when a subpattern that can match an empty
1014        string has an unlimited repetition quantifier, it no longer makes this
1015        optimization. That gives it a stack frame in which to save the data for
1016        checking that an empty string has been matched. Previously this was taken
1017        from the 1000-entry workspace that had been reserved. So now there is no
1018        explicit limit, but more stack is used.
1019    
1020     8. Applied Daniel's patches to solve problems with the import/export magic
1021        syntax that is required for Windows, and which was going wrong for the
1022        pcreposix and pcrecpp parts of the library. These were overlooked when this
1023        problem was solved for the main library.
1024    
1025     9. There were some crude static tests to avoid integer overflow when computing
1026        the size of patterns that contain repeated groups with explicit upper
1027        limits. As the maximum quantifier is 65535, the maximum group length was
1028        set at 30,000 so that the product of these two numbers did not overflow a
1029        32-bit integer. However, it turns out that people want to use groups that
1030        are longer than 30,000 bytes (though not repeat them that many times).
1031        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1032        made it possible to implement the integer overflow checks in a much more
1033        dynamic way, which I have now done. The artificial limitation on group
1034        length has been removed - we now have only the limit on the total length of
1035        the compiled pattern, which depends on the LINK_SIZE setting.
1036    
1037    10. Fixed a bug in the documentation for get/copy named substring when
1038        duplicate names are permitted. If none of the named substrings are set, the
1039        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1040        empty string.
1041    
1042    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1043        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1044        because the ] is interpreted as the first data character and the
1045        terminating ] is not found. PCRE has been made compatible with Perl in this
1046        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1047        cause memory overwriting.
1048    
1049    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1050        string has been matched (to stop an infinite loop). It was not recognizing
1051        a conditional subpattern that could match an empty string if that
1052        subpattern was within another subpattern. For example, it looped when
1053        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1054        condition was not nested. This bug has been fixed.
1055    
1056    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1057        past the start of the subject in the presence of bytes with the top bit
1058        set, for example "\x8aBCD".
1059    
1060    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1061        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1062    
1063    14. Optimized (?!) to (*FAIL).
1064    
1065    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1066        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1067        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1068        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1069        does: it's just the validity check that is more restrictive.
1070    
1071    16. Inserted checks for integer overflows during escape sequence (backslash)
1072        processing, and also fixed erroneous offset values for syntax errors during
1073        backslash processing.
1074    
1075    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1076        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1077    
1078    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1079        caused an overrun.
1080    
1081    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1082        something other than just ASCII characters) inside a group that had an
1083        unlimited repeat caused a loop at compile time (while checking to see
1084        whether the group could match an empty string).
1085    
1086    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1087        [\P{Any}] did so. (Error in the code for printing property names.)
1088    
1089    21. An orphan \E inside a character class could cause a crash.
1090    
1091    22. A repeated capturing bracket such as (A)? could cause a wild memory
1092        reference during compilation.
1093    
1094    23. There are several functions in pcre_compile() that scan along a compiled
1095        expression for various reasons (e.g. to see if it's fixed length for look
1096        behind). There were bugs in these functions when a repeated \p or \P was
1097        present in the pattern. These operators have additional parameters compared
1098        with \d, etc, and these were not being taken into account when moving along
1099        the compiled data. Specifically:
1100    
1101        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1102            length.
1103    
1104        (b) An item such as \pL+ within a repeated group could cause crashes or
1105            loops.
1106    
1107        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1108            "reference to non-existent subpattern" error.
1109    
1110        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1111    
1112    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1113        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1114    
1115    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1116    
1117    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1118        character were causing crashes (broken optimization).
1119    
1120    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1121        \p or \P) caused a compile-time loop.
1122    
1123    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1124        break. For example, the unstudied pattern [\r\n]A does not match the string
1125        "\r\nA" because change 7.0/46 below moves the current point on by two
1126        characters after failing to match at the start. However, the pattern \nA
1127        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1128        the same is true. There doesn't seem any very clean way out of this, but
1129        what I have chosen to do makes the common cases work: PCRE now takes note
1130        of whether there can be an explicit match for \r or \n anywhere in the
1131        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1132        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1133        pattern has explicit CR or LF references.
1134    
1135    29. Added (*CR) etc for changing newline setting at start of pattern.
1136    
1137    
1138  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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