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

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