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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.10 03-Jun-2010
5    ------------------------
6    
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
9    
10    2.  (*ACCEPT) was not working when inside an atomic group.
11    
12    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
15    
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
19    
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
22    
23    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
28    
29    7.  Minor change to pcretest.c to avoid a compiler warning.
30    
31    8.  Added four artifical Unicode properties to help with an option to make
32        \s etc use properties (see next item). The new properties are: Xan
33        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
34    
35    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
36        use Unicode properties. (*UCP) at the start of a pattern can be used to set
37        this option. Modified pcretest to add /W to test this facility. Added
38        REG_UCP to make it available via the POSIX interface.
39    
40    10. Added --line-buffered to pcregrep.
41    
42    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
43        studied, and the match started with a letter with a code point greater than
44        127 whose first byte was different to the first byte of the other case of
45        the letter, the other case of this starting letter was not recognized
46        (#976).
47    
48    12. If a pattern that was studied started with a repeated Unicode property
49        test, for example, \p{Nd}+, there was the theoretical possibility of
50        setting up an incorrect bitmap of starting bytes, but fortunately it could
51        not have actually happened in practice until change 8 above was made (it
52        added property types that matched character-matching opcodes).
53    
54    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
55        possible starting bytes for non-anchored patterns.
56    
57    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
58        \R, and also a number of cases that involve Unicode properties, both
59        explicit and implicit when PCRE_UCP is set.
60    
61    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
62        input, it could crash or give wrong results if characters with values
63        greater than 0xc0 were present in the subject string. (Detail: it assumed
64        UTF-8 input when processing these items.)
65    
66    16. Added a lot of (int) casts to avoid compiler warnings in systems where
67        size_t is 64-bit (#991).
68    
69    17. Added a check for running out of memory when PCRE is compiled with
70        --disable-stack-for-recursion (#990).
71    
72    18. If the last data line in a file for pcretest does not have a newline on
73        the end, a newline was missing in the output.
74    
75    19. The default pcre_chartables.c file recognizes only ASCII characters (values
76        less than 128) in its various bitmaps. However, there is a facility for
77        generating tables according to the current locale when PCRE is compiled. It
78        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
79        characters, are recognized by isspace() and therefore were getting set in
80        these tables. This caused a problem in UTF-8 mode when pcre_study() was
81        used to create a list of bytes that can start a match. For \s, it was
82        including 0x85 and 0xa0, which of course cannot start UTF-8 characters. I
83        have changed the code so that only real ASCII characters (less than 128)
84        are set in this case because the \s etc escapes are documented as
85        recognizing only ASCII characters. (When PCRE_UCP is set - see 9 above -
86        the code is different altogether.)
87    
88    
89    Version 8.02 19-Mar-2010
90    ------------------------
91    
92    1.  The Unicode data tables have been updated to Unicode 5.2.0.
93    
94    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
95        configured.
96    
97    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
98        original author of that file, following a query about its status.
99    
100    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
101        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
102    
103    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
104        quantifier applied to a forward-referencing subroutine call, could compile
105        incorrect code or give the error "internal error: previously-checked
106        referenced subpattern not found".
107    
108    6.  Both MS Visual Studio and Symbian OS have problems with initializing
109        variables to point to external functions. For these systems, therefore,
110        pcre_malloc etc. are now initialized to local functions that call the
111        relevant global functions.
112    
113    7.  There were two entries missing in the vectors called coptable and poptable
114        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
115        I've fixed the data, and added a kludgy way of testing at compile time that
116        the lengths are correct (equal to the number of opcodes).
117    
118    8.  Following on from 7, I added a similar kludge to check the length of the
119        eint vector in pcreposix.c.
120    
121    9.  Error texts for pcre_compile() are held as one long string to avoid too
122        much relocation at load time. To find a text, the string is searched,
123        counting zeros. There was no check for running off the end of the string,
124        which could happen if a new error number was added without updating the
125        string.
126    
127    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
128    
129    11. \K was not working if it appeared in an atomic group or in a group that
130        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
131        \K is "not well defined" if used in an assertion. PCRE now accepts it if
132        the assertion is positive, but not if it is negative.
133    
134    12. Change 11 fortuitously reduced the size of the stack frame used in the
135        "match()" function of pcre_exec.c by one pointer. Forthcoming
136        implementation of support for (*MARK) will need an extra pointer on the
137        stack; I have reserved it now, so that the stack frame size does not
138        decrease.
139    
140    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
141        item in branch that calls a recursion is a subroutine call - as in the
142        second branch in the above example - was incorrectly given the compile-
143        time error "recursive call could loop indefinitely" because pcre_compile()
144        was not correctly checking the subroutine for matching a non-empty string.
145    
146    14. The checks for overrunning compiling workspace could trigger after an
147        overrun had occurred. This is a "should never occur" error, but it can be
148        triggered by pathological patterns such as hundreds of nested parentheses.
149        The checks now trigger 100 bytes before the end of the workspace.
150    
151    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
152    
153    
154    Version 8.01 19-Jan-2010
155    ------------------------
156    
157    1.  If a pattern contained a conditional subpattern with only one branch (in
158        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
159        computed the wrong minimum data length (which is of course zero for such
160        subpatterns). This could cause incorrect "no match" results.
161    
162    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
163        the pattern is reset in the first branch, pcre_compile() failed with
164        "internal error: code overflow at offset...". This happened only when
165        the reset was to the original external option setting. (An optimization
166        abstracts leading options settings into an external setting, which was the
167        cause of this.)
168    
169    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
170        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
171        assertion pattern did not match (meaning that the assertion was true), it
172        was incorrectly treated as false if the SKIP had been reached during the
173        matching. This also applied to assertions used as conditions.
174    
175    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
176        assertion subpattern, including such a pattern used as a condition,
177        unpredictable results occurred, instead of the error return
178        PCRE_ERROR_DFA_UITEM.
179    
180    5.  The C++ GlobalReplace function was not working like Perl for the special
181        situation when an empty string is matched. It now does the fancy magic
182        stuff that is necessary.
183    
184    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
185        removed. (These were left over from very, very early versions of PCRE.)
186    
187    7.  Some cosmetic changes to the code to make life easier when compiling it
188        as part of something else:
189    
190        (a) Change DEBUG to PCRE_DEBUG.
191    
192        (b) In pcre_compile(), rename the member of the "branch_chain" structure
193            called "current" as "current_branch", to prevent a collision with the
194            Linux macro when compiled as a kernel module.
195    
196        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
197            prevent a collision with the Linux macro when compiled as a kernel
198            module.
199    
200    8.  In pcre_compile() there are some checks for integer overflows that used to
201        cast potentially large values to (double). This has been changed to that
202        when building, a check for int64_t is made, and if it is found, it is used
203        instead, thus avoiding the use of floating point arithmetic. (There is no
204        other use of FP in PCRE.) If int64_t is not found, the fallback is to
205        double.
206    
207    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
208        2005 (difference between two addresses compared to an unsigned value).
209    
210    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
211        custom one, because of the following reported problem in Windows:
212    
213          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
214              under Win32.
215          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
216              therefore missing the function definition.
217          - The compiler thus generates a "C" signature for the test function.
218          - The linker fails to find the "C" function.
219          - PCRE fails to configure if asked to do so against libbz2.
220    
221    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
222        messages were output:
223    
224          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
225          rerunning libtoolize, to keep the correct libtool macros in-tree.
226          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
227    
228        I have done both of these things.
229    
230    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
231        most of the time, it *can* run out if it is given a pattern that contains a
232        runaway infinite recursion. I updated the discussion in the pcrestack man
233        page.
234    
235    13. Now that we have gone to the x.xx style of version numbers, the minor
236        version may start with zero. Using 08 or 09 is a bad idea because users
237        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
238        interpreted as invalid octal numbers. I've updated the previous comment in
239        configure.ac, and also added a check that gives an error if 08 or 09 are
240        used.
241    
242    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
243        causing partial matching to fail when the end of the subject matched \W
244        in a UTF-8 pattern where \W was quantified with a minimum of 3.
245    
246    15. There were some discrepancies between the declarations in pcre_internal.h
247        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
248        their definitions. The declarations used "const uschar *" and the
249        definitions used USPTR. Even though USPTR is normally defined as "const
250        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
251        reported that: "This difference in casting confuses some C++ compilers, for
252        example, SunCC recognizes above declarations as different functions and
253        generates broken code for hbpcre." I have changed the declarations to use
254        USPTR.
255    
256    16. GNU libtool is named differently on some systems. The autogen.sh script now
257        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
258        (FreeBSD).
259    
260    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
261        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
262        comment: "Figure out how to create a longlong from a string: strtoll and
263        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
264        instance, but it only takes 2 args instead of 3!"
265    
266    18. A subtle bug concerned with back references has been fixed by a change of
267        specification, with a corresponding code fix. A pattern such as
268        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
269        refers, was giving matches when it shouldn't. For example, xa=xaaa would
270        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
271        same bug. Such groups have to be quantified to be useful, or contained
272        inside another quantified group. (If there's no repetition, the reference
273        can never match.) The problem arises because, having left the group and
274        moved on to the rest of the pattern, a later failure that backtracks into
275        the group uses the captured value from the final iteration of the group
276        rather than the correct earlier one. I have fixed this in PCRE by forcing
277        any group that contains a reference to itself to be an atomic group; that
278        is, there cannot be any backtracking into it once it has completed. This is
279        similar to recursive and subroutine calls.
280    
281    
282    Version 8.00 19-Oct-09
283    ----------------------
284    
285    1.  The table for translating pcre_compile() error codes into POSIX error codes
286        was out-of-date, and there was no check on the pcre_compile() error code
287        being within the table. This could lead to an OK return being given in
288        error.
289    
290    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
291        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
292        in a Windows environment.
293    
294    3.  The pcregrep --count option prints the count for each file even when it is
295        zero, as does GNU grep. However, pcregrep was also printing all files when
296        --files-with-matches was added. Now, when both options are given, it prints
297        counts only for those files that have at least one match. (GNU grep just
298        prints the file name in this circumstance, but including the count seems
299        more useful - otherwise, why use --count?) Also ensured that the
300        combination -clh just lists non-zero counts, with no names.
301    
302    4.  The long form of the pcregrep -F option was incorrectly implemented as
303        --fixed_strings instead of --fixed-strings. This is an incompatible change,
304        but it seems right to fix it, and I didn't think it was worth preserving
305        the old behaviour.
306    
307    5.  The command line items --regex=pattern and --regexp=pattern were not
308        recognized by pcregrep, which required --regex pattern or --regexp pattern
309        (with a space rather than an '='). The man page documented the '=' forms,
310        which are compatible with GNU grep; these now work.
311    
312    6.  No libpcreposix.pc file was created for pkg-config; there was just
313        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
314    
315    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
316        when UCP support is not needed, by modifying the Python script that
317        generates it from Unicode data files. This should not matter if the module
318        is correctly used as a library, but I received one complaint about 50K of
319        unwanted data. My guess is that the person linked everything into his
320        program rather than using a library. Anyway, it does no harm.
321    
322    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
323        was a minimum greater than 1 for a wide character in a possessive
324        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
325        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
326        character. Chaos in the form of incorrect output or a compiling loop could
327        result.
328    
329    9.  The restrictions on what a pattern can contain when partial matching is
330        requested for pcre_exec() have been removed. All patterns can now be
331        partially matched by this function. In addition, if there are at least two
332        slots in the offset vector, the offset of the earliest inspected character
333        for the match and the offset of the end of the subject are set in them when
334        PCRE_ERROR_PARTIAL is returned.
335    
336    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
337        synonymous with PCRE_PARTIAL, for backwards compatibility, and
338        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
339        and may be more useful for multi-segment matching.
340    
341    11. Partial matching with pcre_exec() is now more intuitive. A partial match
342        used to be given if ever the end of the subject was reached; now it is
343        given only if matching could not proceed because another character was
344        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
345        string "Z", which now yields "no match" instead of "partial match". In the
346        case of pcre_dfa_exec(), "no match" is given if every matching path for the
347        final character ended with (*FAIL).
348    
349    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
350        if the pattern had a "must contain" character that was already found in the
351        earlier partial match, unless partial matching was again requested. For
352        example, with the pattern /dog.(body)?/, the "must contain" character is
353        "g". If the first part-match was for the string "dog", restarting with
354        "sbody" failed. This bug has been fixed.
355    
356    13. The string returned by pcre_dfa_exec() after a partial match has been
357        changed so that it starts at the first inspected character rather than the
358        first character of the match. This makes a difference only if the pattern
359        starts with a lookbehind assertion or \b or \B (\K is not supported by
360        pcre_dfa_exec()). It's an incompatible change, but it makes the two
361        matching functions compatible, and I think it's the right thing to do.
362    
363    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
364        so that the demonstration program is easily available in environments where
365        PCRE has not been installed from source.
366    
367    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
368        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
369        library.
370    
371    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
372        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
373        is not the first non-POSIX option to be added. Clearly some people find
374        these options useful.
375    
376    17. If a caller to the POSIX matching function regexec() passes a non-zero
377        value for nmatch with a NULL value for pmatch, the value of
378        nmatch is forced to zero.
379    
380    18. RunGrepTest did not have a test for the availability of the -u option of
381        the diff command, as RunTest does. It now checks in the same way as
382        RunTest, and also checks for the -b option.
383    
384    19. If an odd number of negated classes containing just a single character
385        interposed, within parentheses, between a forward reference to a named
386        subpattern and the definition of the subpattern, compilation crashed with
387        an internal error, complaining that it could not find the referenced
388        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
389        [The bug was that it was starting one character too far in when skipping
390        over the character class, thus treating the ] as data rather than
391        terminating the class. This meant it could skip too much.]
392    
393    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
394        /g option in pcretest when the pattern contains \K, which makes it possible
395        to have an empty string match not at the start, even when the pattern is
396        anchored. Updated pcretest and pcredemo to use this option.
397    
398    21. If the maximum number of capturing subpatterns in a recursion was greater
399        than the maximum at the outer level, the higher number was returned, but
400        with unset values at the outer level. The correct (outer level) value is
401        now given.
402    
403    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
404        PCRE did not set those parentheses (unlike Perl). I have now found a way to
405        make it do so. The string so far is captured, making this feature
406        compatible with Perl.
407    
408    23. The tests have been re-organized, adding tests 11 and 12, to make it
409        possible to check the Perl 5.10 features against Perl 5.10.
410    
411    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
412        pattern matches a fixed length string. PCRE did not allow this; now it
413        does. Neither allows recursion.
414    
415    25. I finally figured out how to implement a request to provide the minimum
416        length of subject string that was needed in order to match a given pattern.
417        (It was back references and recursion that I had previously got hung up
418        on.) This code has now been added to pcre_study(); it finds a lower bound
419        to the length of subject needed. It is not necessarily the greatest lower
420        bound, but using it to avoid searching strings that are too short does give
421        some useful speed-ups. The value is available to calling programs via
422        pcre_fullinfo().
423    
424    26. While implementing 25, I discovered to my embarrassment that pcretest had
425        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
426        study optimizations had never been tested with that matching function.
427        Oops. What is worse, even when it was passed study data, there was a bug in
428        pcre_dfa_exec() that meant it never actually used it. Double oops. There
429        were also very few tests of studied patterns with pcre_dfa_exec().
430    
431    27. If (?| is used to create subpatterns with duplicate numbers, they are now
432        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
433        on the other side of the coin, they are no longer allowed to have different
434        names, because these cannot be distinguished in PCRE, and this has caused
435        confusion. (This is a difference from Perl.)
436    
437    28. When duplicate subpattern names are present (necessarily with different
438        numbers, as required by 27 above), and a test is made by name in a
439        conditional pattern, either for a subpattern having been matched, or for
440        recursion in such a pattern, all the associated numbered subpatterns are
441        tested, and the overall condition is true if the condition is true for any
442        one of them. This is the way Perl works, and is also more like the way
443        testing by number works.
444    
445    
446    Version 7.9 11-Apr-09
447    ---------------------
448    
449    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
450        (pcretest), all targets were linked against these libraries. This included
451        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
452        libraries. This caused unwanted dependencies to be created. This problem
453        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
454        pcretest is linked with readline.
455    
456    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
457        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
458        moved outside it again, because FALSE and TRUE are already defined in AIX,
459        but BOOL is not.
460    
461    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
462        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
463    
464    4.  The pcregrep documentation said spaces were inserted as well as colons (or
465        hyphens) following file names and line numbers when outputting matching
466        lines. This is not true; no spaces are inserted. I have also clarified the
467        wording for the --colour (or --color) option.
468    
469    5.  In pcregrep, when --colour was used with -o, the list of matching strings
470        was not coloured; this is different to GNU grep, so I have changed it to be
471        the same.
472    
473    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
474        each matching line was coloured. Now it goes on to look for further matches
475        of any of the test patterns, which is the same behaviour as GNU grep.
476    
477    7.  A pattern that could match an empty string could cause pcregrep to loop; it
478        doesn't make sense to accept an empty string match in pcregrep, so I have
479        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
480        seems to be how GNU grep behaves.
481    
482    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
483        start or after a newline", because the conditional assertion was not being
484        correctly handled. The rule now is that both the assertion and what follows
485        in the first alternative must satisfy the test.
486    
487    9.  If auto-callout was enabled in a pattern with a conditional group whose
488        condition was an assertion, PCRE could crash during matching, both with
489        pcre_exec() and pcre_dfa_exec().
490    
491    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
492        used for matching.
493    
494    11. Unicode property support in character classes was not working for
495        characters (bytes) greater than 127 when not in UTF-8 mode.
496    
497    12. Added the -M command line option to pcretest.
498    
499    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
500    
501    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
502    
503    16. Added comments and documentation about mis-use of no_arg in the C++
504        wrapper.
505    
506    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
507        from Martin Jerabek that uses macro names for all relevant character and
508        string constants.
509    
510    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
511        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
512        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
513        these, but not everybody uses configure.
514    
515    19. A conditional group that had only one branch was not being correctly
516        recognized as an item that could match an empty string. This meant that an
517        enclosing group might also not be so recognized, causing infinite looping
518        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
519        with the subject "ab", where knowledge that the repeated group can match
520        nothing is needed in order to break the loop.
521    
522    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
523        exec(), but without supplying a callout function, matching went wrong.
524    
525    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
526        leak if the size of the offset vector was greater than 30. When the vector
527        is smaller, the saved offsets during recursion go onto a local stack
528        vector, but for larger vectors malloc() is used. It was failing to free
529        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
530        error, in fact).
531    
532    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
533        heapframe that is used only when UTF-8 support is enabled. This caused no
534        problem, but was untidy.
535    
536    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
537        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
538        included within another project.
539    
540    24. Steven Van Ingelgem's patches to add more options to the CMake support,
541        slightly modified by me:
542    
543          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
544              not building pcregrep.
545    
546          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
547              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
548    
549    25. Forward references, both numeric and by name, in patterns that made use of
550        duplicate group numbers, could behave incorrectly or give incorrect errors,
551        because when scanning forward to find the reference group, PCRE was not
552        taking into account the duplicate group numbers. A pattern such as
553        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
554    
555    26. Changed a few more instances of "const unsigned char *" to USPTR, making
556        the feature of a custom pointer more persuasive (as requested by a user).
557    
558    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
559        pcretest.c, inside #ifndefs, because it seems they are sometimes already
560        pre-defined.
561    
562    28. Added support for (*UTF8) at the start of a pattern.
563    
564    29. Arrange for flags added by the "release type" setting in CMake to be shown
565        in the configuration summary.
566    
567    
568    Version 7.8 05-Sep-08
569    ---------------------
570    
571    1.  Replaced UCP searching code with optimized version as implemented for Ad
572        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
573        stage table and inline lookup instead of a function, giving speed ups of 2
574        to 5 times on some simple patterns that I tested. Permission was given to
575        distribute the MultiStage2.py script that generates the tables (it's not in
576        the tarball, but is in the Subversion repository).
577    
578    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
579        scripts.
580    
581    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
582        a group with a zero qualifier. The result of the study could be incorrect,
583        or the function might crash, depending on the pattern.
584    
585    4.  Caseless matching was not working for non-ASCII characters in back
586        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
587        It now works when Unicode Property Support is available.
588    
589    5.  In pcretest, an escape such as \x{de} in the data was always generating
590        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
591        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
592        truncation.
593    
594    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
595    
596    7.  Added two (int) casts to pcregrep when printing the difference of two
597        pointers, in case they are 64-bit values.
598    
599    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
600        test 2 if it fails.
601    
602    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
603        and a #define of that name to empty if it is not externally set. This is to
604        allow users of MSVC to set it if necessary.
605    
606    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
607        the convenience functions in the pcre_get.c source file.
608    
609    11. An option change at the start of a pattern that had top-level alternatives
610        could cause overwriting and/or a crash. This command provoked a crash in
611        some environments:
612    
613          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
614    
615        This potential security problem was recorded as CVE-2008-2371.
616    
617    12. For a pattern where the match had to start at the beginning or immediately
618        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
619        pcre_dfa_exec() could read past the end of the passed subject if there was
620        no match. To help with detecting such bugs (e.g. with valgrind), I modified
621        pcretest so that it places the subject at the end of its malloc-ed buffer.
622    
623    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
624        exec() might read past the end of the data buffer in UTF-8 mode.
625    
626    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
627        the data contained the byte 0x85 as part of a UTF-8 character within its
628        first line. This applied both to normal and DFA matching.
629    
630    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
631        /^[^d]*?$/8 failed to match "abc".
632    
633    16. Added a missing copyright notice to pcrecpp_internal.h.
634    
635    17. Make it more clear in the documentation that values returned from
636        pcre_exec() in ovector are byte offsets, not character counts.
637    
638    18. Tidied a few places to stop certain compilers from issuing warnings.
639    
640    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
641        supplied by Stefan Weber. I made a further small update for 7.8 because
642        there is a change of source arrangements: the pcre_searchfuncs.c module is
643        replaced by pcre_ucd.c.
644    
645    
646    Version 7.7 07-May-08
647    ---------------------
648    
649    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
650        a string to a long long, pretend we don't even have a long long." This is
651        done by checking for the strtoq, strtoll, and _strtoi64 functions.
652    
653    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
654        pre-7.6 versions, which defined a global no_arg variable instead of putting
655        it in the RE class. (See also #8 below.)
656    
657    3.  Remove a line of dead code, identified by coverity and reported by Nuno
658        Lopes.
659    
660    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
661    
662        (1) The include/exclude patterns were being applied to the whole pathnames
663            of files, instead of just to the final components.
664    
665        (2) If there was more than one level of directory, the subdirectories were
666            skipped unless they satisfied the include/exclude conditions. This is
667            inconsistent with GNU grep (and could even be seen as contrary to the
668            pcregrep specification - which I improved to make it absolutely clear).
669            The action now is always to scan all levels of directory, and just
670            apply the include/exclude patterns to regular files.
671    
672    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
673        --exclude_dir in the tests to avoid scanning .svn directories.
674    
675    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
676        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
677        doesn't support NULs in patterns.
678    
679    7.  Added some missing "const"s to declarations of static tables in
680        pcre_compile.c and pcre_dfa_exec.c.
681    
682    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
683        caused by fix #2  above. (Subsequently also a second patch to fix the
684        first patch. And a third patch - this was a messy problem.)
685    
686    9.  Applied Craig's patch to remove the use of push_back().
687    
688    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
689        matching function regexec().
690    
691    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
692        which, however, unlike Perl's \g{...}, are subroutine calls, not back
693        references. PCRE supports relative numbers with this syntax (I don't think
694        Oniguruma does).
695    
696    12. Previously, a group with a zero repeat such as (...){0} was completely
697        omitted from the compiled regex. However, this means that if the group
698        was called as a subroutine from elsewhere in the pattern, things went wrong
699        (an internal error was given). Such groups are now left in the compiled
700        pattern, with a new opcode that causes them to be skipped at execution
701        time.
702    
703    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
704        to the way PCRE behaves:
705    
706        (a) A lone ] character is dis-allowed (Perl treats it as data).
707    
708        (b) A back reference to an unmatched subpattern matches an empty string
709            (Perl fails the current match path).
710    
711        (c) A data ] in a character class must be notated as \] because if the
712            first data character in a class is ], it defines an empty class. (In
713            Perl it is not possible to have an empty class.) The empty class []
714            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
715            The negative empty class [^] matches any one character, independently
716            of the DOTALL setting.
717    
718    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
719        non-existent subpattern following a character class starting with ']' and
720        containing () gave an internal compiling error instead of "reference to
721        non-existent subpattern". Fortunately, when the pattern did exist, the
722        compiled code was correct. (When scanning forwards to check for the
723        existencd of the subpattern, it was treating the data ']' as terminating
724        the class, so got the count wrong. When actually compiling, the reference
725        was subsequently set up correctly.)
726    
727    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
728        it was being rejected as not supported by pcre_dfa_exec(), even though
729        other assertions are supported. I have made pcre_dfa_exec() support
730        (*FAIL).
731    
732    16. The implementation of 13c above involved the invention of a new opcode,
733        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
734        cannot be changed at match time, I realized I could make a small
735        improvement to matching performance by compiling OP_ALLANY instead of
736        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
737        on the OP_ANY path.
738    
739    17. Compiling pcretest on Windows with readline support failed without the
740        following two fixes: (1) Make the unistd.h include conditional on
741        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
742    
743    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
744        ncurses library to be included for pcretest when ReadLine support is
745        requested, but also to allow for it to be overridden. This patch came from
746        Daniel Bergström.
747    
748    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
749        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
750        any errors with the current Unicode tables. Thanks to Peter Kankowski for
751        spotting this.
752    
753    
754    Version 7.6 28-Jan-08
755    ---------------------
756    
757    1.  A character class containing a very large number of characters with
758        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
759        overflow.
760    
761    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
762        HAVE_LONG_LONG is not defined.
763    
764    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
765        bring them up to date and include new features. This patch includes:
766    
767        - Fixed PH's badly added libz and libbz2 support.
768        - Fixed a problem with static linking.
769        - Added pcredemo. [But later removed - see 7 below.]
770        - Fixed dftables problem and added an option.
771        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
772            HAVE_LONG_LONG.
773        - Added readline support for pcretest.
774        - Added an listing of the option settings after cmake has run.
775    
776    4.  A user submitted a patch to Makefile that makes it easy to create
777        "pcre.dll" under mingw when using Configure/Make. I added stuff to
778        Makefile.am that cause it to include this special target, without
779        affecting anything else. Note that the same mingw target plus all
780        the other distribution libraries and programs are now supported
781        when configuring with CMake (see 6 below) instead of with
782        Configure/Make.
783    
784    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
785        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
786        exported in the Windows port". It has not yet been confirmed that the patch
787        solves the problem, but it does no harm.
788    
789    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
790        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
791        with CMake, and also correct the comment about stack recursion.
792    
793    7.  Remove the automatic building of pcredemo from the ./configure system and
794        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
795        of a program that users should build themselves after PCRE is installed, so
796        building it automatically is not really right. What is more, it gave
797        trouble in some build environments.
798    
799    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
800    
801    
802    Version 7.5 10-Jan-08
803    ---------------------
804    
805    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
806        values in parens when parsing an RE using the C++ wrapper."
807    
808    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
809        Characters greater than 255 were excluded from the class instead of being
810        included.
811    
812    3.  The same bug as (2) above applied to negated POSIX classes such as
813        [:^space:].
814    
815    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
816        defined or documented. It seems to have been a typo for PCRE_STATIC, so
817        I have changed it.
818    
819    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
820        first named subpattern) and a construct such as (?&a) would reference the
821        first named subpattern whose name started with "a" (in other words, the
822        length check was missing). Both these problems are fixed. "Subpattern name
823        expected" is now given for (?&) (a zero-length name), and this patch also
824        makes it give the same error for \k'' (previously it complained that that
825        was a reference to a non-existent subpattern).
826    
827    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
828        this is right because (?- can be followed by option settings as well as by
829        digits. I have, however, made the messages clearer.
830    
831    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
832        than the number used in the conditional) now cause a compile-time error.
833        This is actually not compatible with Perl, which accepts such patterns, but
834        treats the conditional as always being FALSE (as PCRE used to), but it
835        seems to me that giving a diagnostic is better.
836    
837    8.  Change "alphameric" to the more common word "alphanumeric" in comments
838        and messages.
839    
840    9.  Fix two occurrences of "backslash" in comments that should have been
841        "backspace".
842    
843    10. Remove two redundant lines of code that can never be obeyed (their function
844        was moved elsewhere).
845    
846    11. The program that makes PCRE's Unicode character property table had a bug
847        which caused it to generate incorrect table entries for sequences of
848        characters that have the same character type, but are in different scripts.
849        It amalgamated them into a single range, with the script of the first of
850        them. In other words, some characters were in the wrong script. There were
851        thirteen such cases, affecting characters in the following ranges:
852    
853          U+002b0 - U+002c1
854          U+0060c - U+0060d
855          U+0061e - U+00612
856          U+0064b - U+0065e
857          U+0074d - U+0076d
858          U+01800 - U+01805
859          U+01d00 - U+01d77
860          U+01d9b - U+01dbf
861          U+0200b - U+0200f
862          U+030fc - U+030fe
863          U+03260 - U+0327f
864          U+0fb46 - U+0fbb1
865          U+10450 - U+1049d
866    
867    12. The -o option (show only the matching part of a line) for pcregrep was not
868        compatible with GNU grep in that, if there was more than one match in a
869        line, it showed only the first of them. It now behaves in the same way as
870        GNU grep.
871    
872    13. If the -o and -v options were combined for pcregrep, it printed a blank
873        line for every non-matching line. GNU grep prints nothing, and pcregrep now
874        does the same. The return code can be used to tell if there were any
875        non-matching lines.
876    
877    14. Added --file-offsets and --line-offsets to pcregrep.
878    
879    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
880        infinitely looping recursion. The bug was that positive lookaheads were not
881        being skipped when checking for a possible empty match (negative lookaheads
882        and both kinds of lookbehind were skipped).
883    
884    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
885        inclusion of <windows.h> to before rather than after the definition of
886        INVALID_FILE_ATTRIBUTES (patch from David Byron).
887    
888    17. Specifying a possessive quantifier with a specific limit for a Unicode
889        character property caused pcre_compile() to compile bad code, which led at
890        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
891        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
892        caused the error; without that there was no problem.
893    
894    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
895    
896    19. Added --enable-pcretest-libreadline.
897    
898    20. In pcrecpp.cc, the variable 'count' was incremented twice in
899        RE::GlobalReplace(). As a result, the number of replacements returned was
900        double what it should be. I removed one of the increments, but Craig sent a
901        later patch that removed the other one (the right fix) and added unit tests
902        that check the return values (which was not done before).
903    
904    21. Several CMake things:
905    
906        (1) Arranged that, when cmake is used on Unix, the libraries end up with
907            the names libpcre and libpcreposix, not just pcre and pcreposix.
908    
909        (2) The above change means that pcretest and pcregrep are now correctly
910            linked with the newly-built libraries, not previously installed ones.
911    
912        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
913    
914    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
915        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
916        UTF-8 newline character). The key issue is that the pattern starts .*;
917        this means that the match must be either at the beginning, or after a
918        newline. The bug was in the code for advancing after a failed match and
919        checking that the new position followed a newline. It was not taking
920        account of UTF-8 characters correctly.
921    
922    23. PCRE was behaving differently from Perl in the way it recognized POSIX
923        character classes. PCRE was not treating the sequence [:...:] as a
924        character class unless the ... were all letters. Perl, however, seems to
925        allow any characters between [: and :], though of course it rejects as
926        unknown any "names" that contain non-letters, because all the known class
927        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
928        for example, whereas PCRE did not - it did not recognize a POSIX character
929        class. This seemed a bit dangerous, so the code has been changed to be
930        closer to Perl. The behaviour is not identical to Perl, because PCRE will
931        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
932        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
933        Perl does, and where it didn't before.
934    
935    24. Rewrite so as to remove the single use of %n from pcregrep because in some
936        Windows environments %n is disabled by default.
937    
938    
939    Version 7.4 21-Sep-07
940    ---------------------
941    
942    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
943        means that a class such as [\s] counted as "explicit reference to CR or
944        LF". That isn't really right - the whole point of the change was to try to
945        help when there was an actual mention of one of the two characters. So now
946        the change happens only if \r or \n (or a literal CR or LF) character is
947        encountered.
948    
949    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
950        of both had grown to the point where there were only 3 bits left.
951        Fortunately, there was spare space in the data structure, and so I have
952        moved the internal flags into a new 16-bit field to free up more option
953        bits.
954    
955    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
956        but did not set the internal JCHANGED flag - either of these is enough to
957        control the way the "get" function works - but the PCRE_INFO_JCHANGED
958        facility is supposed to tell if (?J) was ever used, so now (?J) at the
959        start sets both bits.
960    
961    4.  Added options (at build time, compile time, exec time) to change \R from
962        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
963    
964    5.  doc/pcresyntax.html was missing from the distribution.
965    
966    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
967        compatibility, even though it is no longer used.
968    
969    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
970        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
971        windows.h file is present (where different names are used). [This was
972        reversed later after testing - see 16 below.]
973    
974    8.  Changed all #include <config.h> to #include "config.h". There were also
975        some further <pcre.h> cases that I changed to "pcre.h".
976    
977    9.  When pcregrep was used with the --colour option, it missed the line ending
978        sequence off the lines that it output.
979    
980    10. It was pointed out to me that arrays of string pointers cause lots of
981        relocations when a shared library is dynamically loaded. A technique of
982        using a single long string with a table of offsets can drastically reduce
983        these. I have refactored PCRE in four places to do this. The result is
984        dramatic:
985    
986          Originally:                          290
987          After changing UCP table:            187
988          After changing error message table:   43
989          After changing table of "verbs"       36
990          After changing table of Posix names   22
991    
992        Thanks to the folks working on Gregex for glib for this insight.
993    
994    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
995        unicode-properties was also set.
996    
997    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
998    
999    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1000        checked only for CRLF.
1001    
1002    14. Added casts to pcretest.c to avoid compiler warnings.
1003    
1004    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1005    
1006    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1007        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1008        entirely. This removes changes made in 7 above.
1009    
1010    17. The CMake files have been updated, and there is now more information about
1011        building with CMake in the NON-UNIX-USE document.
1012    
1013    
1014    Version 7.3 28-Aug-07
1015    ---------------------
1016    
1017     1. In the rejigging of the build system that eventually resulted in 7.1, the
1018        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1019        brackets there is not right, since it causes compilers to look for an
1020        installed pcre.h, not the version that is in the source that is being
1021        compiled (which of course may be different). I have changed it back to:
1022    
1023          #include "pcre.h"
1024    
1025        I have a vague recollection that the change was concerned with compiling in
1026        different directories, but in the new build system, that is taken care of
1027        by the VPATH setting the Makefile.
1028    
1029     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1030        when the subject happened to end in the byte 0x85 (e.g. if the last
1031        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1032        characters but of course it shouldn't be taken as a newline when it is part
1033        of another character. The bug was that, for an unlimited repeat of . in
1034        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1035        characters when looking for a newline.
1036    
1037     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1038    
1039     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1040        in debug output.
1041    
1042     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1043        long printing in the pcrecpp unittest when running under MinGW.
1044    
1045     6. ESC_K was left out of the EBCDIC table.
1046    
1047     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1048        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1049        limit also applies to "virtual nesting" when a pattern is recursive, and in
1050        this case 1000 isn't so big. I have been able to remove this limit at the
1051        expense of backing off one optimization in certain circumstances. Normally,
1052        when pcre_exec() would call its internal match() function recursively and
1053        immediately return the result unconditionally, it uses a "tail recursion"
1054        feature to save stack. However, when a subpattern that can match an empty
1055        string has an unlimited repetition quantifier, it no longer makes this
1056        optimization. That gives it a stack frame in which to save the data for
1057        checking that an empty string has been matched. Previously this was taken
1058        from the 1000-entry workspace that had been reserved. So now there is no
1059        explicit limit, but more stack is used.
1060    
1061     8. Applied Daniel's patches to solve problems with the import/export magic
1062        syntax that is required for Windows, and which was going wrong for the
1063        pcreposix and pcrecpp parts of the library. These were overlooked when this
1064        problem was solved for the main library.
1065    
1066     9. There were some crude static tests to avoid integer overflow when computing
1067        the size of patterns that contain repeated groups with explicit upper
1068        limits. As the maximum quantifier is 65535, the maximum group length was
1069        set at 30,000 so that the product of these two numbers did not overflow a
1070        32-bit integer. However, it turns out that people want to use groups that
1071        are longer than 30,000 bytes (though not repeat them that many times).
1072        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1073        made it possible to implement the integer overflow checks in a much more
1074        dynamic way, which I have now done. The artificial limitation on group
1075        length has been removed - we now have only the limit on the total length of
1076        the compiled pattern, which depends on the LINK_SIZE setting.
1077    
1078    10. Fixed a bug in the documentation for get/copy named substring when
1079        duplicate names are permitted. If none of the named substrings are set, the
1080        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1081        empty string.
1082    
1083    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1084        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1085        because the ] is interpreted as the first data character and the
1086        terminating ] is not found. PCRE has been made compatible with Perl in this
1087        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1088        cause memory overwriting.
1089    
1090    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1091        string has been matched (to stop an infinite loop). It was not recognizing
1092        a conditional subpattern that could match an empty string if that
1093        subpattern was within another subpattern. For example, it looped when
1094        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1095        condition was not nested. This bug has been fixed.
1096    
1097    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1098        past the start of the subject in the presence of bytes with the top bit
1099        set, for example "\x8aBCD".
1100    
1101    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1102        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1103    
1104    14. Optimized (?!) to (*FAIL).
1105    
1106    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1107        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1108        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1109        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1110        does: it's just the validity check that is more restrictive.
1111    
1112    16. Inserted checks for integer overflows during escape sequence (backslash)
1113        processing, and also fixed erroneous offset values for syntax errors during
1114        backslash processing.
1115    
1116    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1117        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1118    
1119    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1120        caused an overrun.
1121    
1122    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1123        something other than just ASCII characters) inside a group that had an
1124        unlimited repeat caused a loop at compile time (while checking to see
1125        whether the group could match an empty string).
1126    
1127    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1128        [\P{Any}] did so. (Error in the code for printing property names.)
1129    
1130    21. An orphan \E inside a character class could cause a crash.
1131    
1132    22. A repeated capturing bracket such as (A)? could cause a wild memory
1133        reference during compilation.
1134    
1135    23. There are several functions in pcre_compile() that scan along a compiled
1136        expression for various reasons (e.g. to see if it's fixed length for look
1137        behind). There were bugs in these functions when a repeated \p or \P was
1138        present in the pattern. These operators have additional parameters compared
1139        with \d, etc, and these were not being taken into account when moving along
1140        the compiled data. Specifically:
1141    
1142        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1143            length.
1144    
1145        (b) An item such as \pL+ within a repeated group could cause crashes or
1146            loops.
1147    
1148        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1149            "reference to non-existent subpattern" error.
1150    
1151        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1152    
1153    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1154        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1155    
1156    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1157    
1158    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1159        character were causing crashes (broken optimization).
1160    
1161    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1162        \p or \P) caused a compile-time loop.
1163    
1164    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1165        break. For example, the unstudied pattern [\r\n]A does not match the string
1166        "\r\nA" because change 7.0/46 below moves the current point on by two
1167        characters after failing to match at the start. However, the pattern \nA
1168        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1169        the same is true. There doesn't seem any very clean way out of this, but
1170        what I have chosen to do makes the common cases work: PCRE now takes note
1171        of whether there can be an explicit match for \r or \n anywhere in the
1172        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1173        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1174        pattern has explicit CR or LF references.
1175    
1176    29. Added (*CR) etc for changing newline setting at start of pattern.
1177    
1178    
1179    Version 7.2 19-Jun-07
1180    ---------------------
1181    
1182     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1183        which is apparently normally available under Windows.
1184    
1185     2. Re-jig the pcregrep tests with different newline settings in an attempt
1186        to make them independent of the local environment's newline setting.
1187    
1188     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1189    
1190     4. Some of the "internals" tests were previously cut out when the link size
1191        was not 2, because the output contained actual offsets. The recent new
1192        "Z" feature of pcretest means that these can be cut out, making the tests
1193        usable with all link sizes.
1194    
1195     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1196        stack recursion. This gives a massive performance boost under BSD, but just
1197        a small improvement under Linux. However, it saves one field in the frame
1198        in all cases.
1199    
1200     6. Added more features from the forthcoming Perl 5.10:
1201    
1202        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1203            recursion call. It refers to the nth most recently opened parentheses.
1204    
1205        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1206            to be opened parentheses.
1207    
1208        (c) Conditions that refer to capturing parentheses can be specified
1209            relatively, for example, (?(-2)... or (?(+3)...
1210    
1211        (d) \K resets the start of the current match so that everything before
1212            is not part of it.
1213    
1214        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1215    
1216        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1217            reference syntax.
1218    
1219        (g) (?| introduces a group in which the numbering of parentheses in each
1220            alternative starts with the same number.
1221    
1222        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1223    
1224     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1225        PCRE_INFO_JCHANGED.
1226    
1227     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1228        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1229        for detecting groups that can match an empty string.
1230    
1231     9. A pattern with a very large number of alternatives (more than several
1232        hundred) was running out of internal workspace during the pre-compile
1233        phase, where pcre_compile() figures out how much memory will be needed. A
1234        bit of new cunning has reduced the workspace needed for groups with
1235        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1236        workspace instead of running out of the 4096 that are available.
1237    
1238    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1239    
1240    11. Applied patch from Google to remove an optimization that didn't quite work.
1241        The report of the bug said:
1242    
1243          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1244          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1245          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1246    
1247    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1248        it matched the wrong number of bytes.
1249    
1250    
1251    Version 7.1 24-Apr-07
1252    ---------------------
1253    
1254     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1255        that is more "standard", making use of automake and other Autotools. There
1256        is some re-arrangement of the files and adjustment of comments consequent
1257        on this.
1258    
1259     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1260        for recursive directory scanning broke on some systems because the files
1261        are not scanned in any specific order and on different systems the order
1262        was different. A call to "sort" has been inserted into RunGrepTest for the
1263        approprate test as a short-term fix. In the longer term there may be an
1264        alternative.
1265    
1266     3. I had an email from Eric Raymond about problems translating some of PCRE's
1267        man pages to HTML (despite the fact that I distribute HTML pages, some
1268        people do their own conversions for various reasons). The problems
1269        concerned the use of low-level troff macros .br and .in. I have therefore
1270        removed all such uses from the man pages (some were redundant, some could
1271        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1272        HTML has been updated to handle .nf/.fi and to complain if it encounters
1273        .br or .in.
1274    
1275     4. Updated comments in configure.ac that get placed in config.h.in and also
1276        arranged for config.h to be included in the distribution, with the name
1277        config.h.generic, for the benefit of those who have to compile without
1278        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1279    
1280     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1281        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1282        makevp.bat for the current PCRE, using the additional files
1283        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1284    
1285     6. A Windows user reported a minor discrepancy with test 2, which turned out
1286        to be caused by a trailing space on an input line that had got lost in his
1287        copy. The trailing space was an accident, so I've just removed it.
1288    
1289     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1290        that is needed.
1291    
1292     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1293        as "const" (a) because they are and (b) because it helps the PHP
1294        maintainers who have recently made a script to detect big data structures
1295        in the php code that should be moved to the .rodata section. I remembered
1296        to update Builducptable as well, so it won't revert if ucptable.h is ever
1297        re-created.
1298    
1299     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1300        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1301        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1302        support is not required. This saves 1.5-2K of code, which is important in
1303        some applications.
1304    
1305        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1306        so as not to refer to the tables, even though these functions will never be
1307        called when UTF-8 support is disabled. Otherwise there are problems with a
1308        shared library.
1309    
1310    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1311    
1312        (a) It was defining its arguments as char * instead of void *.
1313    
1314        (b) It was assuming that all moves were upwards in memory; this was true
1315            a long time ago when I wrote it, but is no longer the case.
1316    
1317        The emulated memove() is provided for those environments that have neither
1318        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1319        is clearly not the case, as these two bugs were recently reported.
1320    
1321    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1322        and Detrail to create the HTML documentation, the .txt form of the man
1323        pages, and it removes trailing spaces from listed files. It also creates
1324        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1325        case, it wraps all the #defines with #ifndefs. This script should be run
1326        before "make dist".
1327    
1328    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1329        with Unicode property support.
1330    
1331        (a) For a maximizing quantifier, if the two different cases of the
1332            character were of different lengths in their UTF-8 codings (there are
1333            some cases like this - I found 11), and the matching function had to
1334            back up over a mixture of the two cases, it incorrectly assumed they
1335            were both the same length.
1336    
1337        (b) When PCRE was configured to use the heap rather than the stack for
1338            recursion during matching, it was not correctly preserving the data for
1339            the other case of a UTF-8 character when checking ahead for a match
1340            while processing a minimizing repeat. If the check also involved
1341            matching a wide character, but failed, corruption could cause an
1342            erroneous result when trying to check for a repeat of the original
1343            character.
1344    
1345    13. Some tidying changes to the testing mechanism:
1346    
1347        (a) The RunTest script now detects the internal link size and whether there
1348            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1349            values substituted by "configure". (The RunGrepTest script already did
1350            this for UTF-8.) The configure.ac script no longer substitutes the
1351            relevant variables.
1352    
1353        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1354            with length and offset values. This means that the output is different
1355            for different internal link sizes. Test 2 is skipped for link sizes
1356            other than 2 because of this, bypassing the problem. Unfortunately,
1357            there was also a test in test 3 (the locale tests) that used /B and
1358            failed for link sizes other than 2. Rather than cut the whole test out,
1359            I have added a new /Z option to pcretest that replaces the length and
1360            offset values with spaces. This is now used to make test 3 independent
1361            of link size. (Test 2 will be tidied up later.)
1362    
1363    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1364        segmentation fault instead of returning the appropriate error message.
1365    
1366    15. In multiline mode when the newline sequence was set to "any", the pattern
1367        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1368        This doesn't seem right; it now treats the CRLF combination as the line
1369        ending, and so does not match in that case. It's only a pattern such as ^$
1370        that would hit this one: something like ^ABC$ would have failed after \r
1371        and then tried again after \r\n.
1372    
1373    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1374        in an attempt to make files that differ only in their line terminators
1375        compare equal. This works on Linux.
1376    
1377    17. Under certain error circumstances pcregrep might try to free random memory
1378        as it exited. This is now fixed, thanks to valgrind.
1379    
1380    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1381        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1382        was because its rules for how to advance for /g after matching an empty
1383        string at the end of a line did not allow for this case. They now check for
1384        it specially.
1385    
1386    20. pcretest is supposed to handle patterns and data of any length, by
1387        extending its buffers when necessary. It was getting this wrong when the
1388        buffer for a data line had to be extended.
1389    
1390    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1391        CRLF as a newline sequence.
1392    
1393    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1394        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1395        I have nevertheless tidied it up.
1396    
1397    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1398    
1399    24. Added a man page for pcre-config.
1400    
1401    
1402    Version 7.0 19-Dec-06
1403    ---------------------
1404    
1405     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1406        moving to gcc 4.1.1.
1407    
1408     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1409        sys/time.h, which is documented as needed for this function. It doesn't
1410        seem to matter on Linux, but it showed up on some releases of OS X.
1411    
1412     3. It seems that there are systems where bytes whose values are greater than
1413        127 match isprint() in the "C" locale. The "C" locale should be the
1414        default when a C program starts up. In most systems, only ASCII printing
1415        characters match isprint(). This difference caused the output from pcretest
1416        to vary, making some of the tests fail. I have changed pcretest so that:
1417    
1418        (a) When it is outputting text in the compiled version of a pattern, bytes
1419            other than 32-126 are always shown as hex escapes.
1420    
1421        (b) When it is outputting text that is a matched part of a subject string,
1422            it does the same, unless a different locale has been set for the match
1423            (using the /L modifier). In this case, it uses isprint() to decide.
1424    
1425     4. Fixed a major bug that caused incorrect computation of the amount of memory
1426        required for a compiled pattern when options that changed within the
1427        pattern affected the logic of the preliminary scan that determines the
1428        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1429        that the computed length was too small. The symptoms of this bug were
1430        either the PCRE error "internal error: code overflow" from pcre_compile(),
1431        or a glibc crash with a message such as "pcretest: free(): invalid next
1432        size (fast)". Examples of patterns that provoked this bug (shown in
1433        pcretest format) are:
1434    
1435          /(?-x: )/x
1436          /(?x)(?-x: \s*#\s*)/
1437          /((?i)[\x{c0}])/8
1438          /(?i:[\x{c0}])/8
1439    
1440        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1441        is now done differently.
1442    
1443     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1444        wrapper classes; (b) implement a new function in the C++ scanner that is
1445        more efficient than the old way of doing things because it avoids levels of
1446        recursion in the regex matching; (c) add a paragraph to the documentation
1447        for the FullMatch() function.
1448    
1449     6. The escape sequence \n was being treated as whatever was defined as
1450        "newline". Not only was this contrary to the documentation, which states
1451        that \n is character 10 (hex 0A), but it also went horribly wrong when
1452        "newline" was defined as CRLF. This has been fixed.
1453    
1454     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1455        was being set to -1 for the "end of line" case (supposedly a value that no
1456        character can have). Though this value is never used (the check for end of
1457        line is "zero bytes in current character"), it caused compiler complaints.
1458        I've changed it to 0xffffffff.
1459    
1460     8. In pcre_version.c, the version string was being built by a sequence of
1461        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1462        string (as it is for production releases) called a macro with an empty
1463        argument. The C standard says the result of this is undefined. The gcc
1464        compiler treats it as an empty string (which was what was wanted) but it is
1465        reported that Visual C gives an error. The source has been hacked around to
1466        avoid this problem.
1467    
1468     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1469        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1470        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1471        of them did).
1472    
1473    10. Originally, pcretest opened its input and output without "b"; then I was
1474        told that "b" was needed in some environments, so it was added for release
1475        5.0 to both the input and output. (It makes no difference on Unix-like
1476        systems.) Later I was told that it is wrong for the input on Windows. I've
1477        now abstracted the modes into two macros, to make it easier to fiddle with
1478        them, and removed "b" from the input mode under Windows.
1479    
1480    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1481    
1482    12. Added -help and --help to pcretest as an official way of being reminded
1483        of the options.
1484    
1485    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1486        and pcrecpp.cc because they annoy compilers at high warning levels.
1487    
1488    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1489    
1490    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1491        scripts are not C programs :-) and which was not noticed because it works
1492        on Linux.
1493    
1494    16. pcretest is supposed to handle any length of pattern and data line (as one
1495        line or as a continued sequence of lines) by extending its input buffer if
1496        necessary. This feature was broken for very long pattern lines, leading to
1497        a string of junk being passed to pcre_compile() if the pattern was longer
1498        than about 50K.
1499    
1500    17. I have done a major re-factoring of the way pcre_compile() computes the
1501        amount of memory needed for a compiled pattern. Previously, there was code
1502        that made a preliminary scan of the pattern in order to do this. That was
1503        OK when PCRE was new, but as the facilities have expanded, it has become
1504        harder and harder to keep it in step with the real compile phase, and there
1505        have been a number of bugs (see for example, 4 above). I have now found a
1506        cunning way of running the real compile function in a "fake" mode that
1507        enables it to compute how much memory it would need, while actually only
1508        ever using a few hundred bytes of working memory and without too many
1509        tests of the mode. This should make future maintenance and development
1510        easier. A side effect of this work is that the limit of 200 on the nesting
1511        depth of parentheses has been removed (though this was never a serious
1512        limitation, I suspect). However, there is a downside: pcre_compile() now
1513        runs more slowly than before (30% or more, depending on the pattern). I
1514        hope this isn't a big issue. There is no effect on runtime performance.
1515    
1516    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1517        newline (only possible for the last line of a file) and it was a
1518        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1519    
1520    19. Added additional timing features to pcretest. (1) The -tm option now times
1521        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1522        separate command line item, by a number that specifies the number of
1523        repeats to use when timing. The default is 50000; this gives better
1524        precision, but takes uncomfortably long for very large patterns.
1525    
1526    20. Extended pcre_study() to be more clever in cases where a branch of a
1527        subpattern has no definite first character. For example, (a*|b*)[cd] would
1528        previously give no result from pcre_study(). Now it recognizes that the
1529        first character must be a, b, c, or d.
1530    
1531    21. There was an incorrect error "recursive call could loop indefinitely" if
1532        a subpattern (or the entire pattern) that was being tested for matching an
1533        empty string contained only one non-empty item after a nested subpattern.
1534        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1535        incorrectly, because the \d was being skipped in the check.
1536    
1537    22. The pcretest program now has a new pattern option /B and a command line
1538        option -b, which is equivalent to adding /B to every pattern. This causes
1539        it to show the compiled bytecode, without the additional information that
1540        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1541        is the same as /B/I).
1542    
1543    23. A new optimization is now able automatically to treat some sequences such
1544        as a*b as a*+b. More specifically, if something simple (such as a character
1545        or a simple class like \d) has an unlimited quantifier, and is followed by
1546        something that cannot possibly match the quantified thing, the quantifier
1547        is automatically "possessified".
1548    
1549    24. A recursive reference to a subpattern whose number was greater than 39
1550        went wrong under certain circumstances in UTF-8 mode. This bug could also
1551        have affected the operation of pcre_study().
1552    
1553    25. Realized that a little bit of performance could be had by replacing
1554        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1555    
1556    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1557    
1558    27. Possessive quantifiers such as a++ were previously implemented by turning
1559        them into atomic groups such as ($>a+). Now they have their own opcodes,
1560        which improves performance. This includes the automatically created ones
1561        from 23 above.
1562    
1563    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1564        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1565        the first matched character to be a colon. This applied both to named and
1566        numbered groups.
1567    
1568    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1569    
1570    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1571        building PCRE on Windows easier, so I have included it in the distribution.
1572    
1573    31. There is now a check in pcretest against a ridiculously large number being
1574        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1575        loop, the loop is abandoned.
1576    
1577    32. Forward references to subpatterns in conditions such as (?(2)...) where
1578        subpattern 2 is defined later cause pcre_compile() to search forwards in
1579        the pattern for the relevant set of parentheses. This search went wrong
1580        when there were unescaped parentheses in a character class, parentheses
1581        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1582    
1583    33. "Subroutine" calls and backreferences were previously restricted to
1584        referencing subpatterns earlier in the regex. This restriction has now
1585        been removed.
1586    
1587    34. Added a number of extra features that are going to be in Perl 5.10. On the
1588        whole, these are just syntactic alternatives for features that PCRE had
1589        previously implemented using the Python syntax or my own invention. The
1590        other formats are all retained for compatibility.
1591    
1592        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1593            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1594            also .NET compatible.
1595    
1596        (b) A recursion or subroutine call to a named group can now be defined as
1597            (?&name) as well as (?P>name).
1598    
1599        (c) A backreference to a named group can now be defined as \k<name> or
1600            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1601            5.10, are also .NET compatible.
1602    
1603        (d) A conditional reference to a named group can now use the syntax
1604            (?(<name>) or (?('name') as well as (?(name).
1605    
1606        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1607            groups (named and numbered) that are never evaluated inline, but can be
1608            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1609            is always false. There may be only one alternative in such a group.
1610    
1611        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1612            as the simple (?(R). The condition is true only if the most recent
1613            recursion is that of the given number or name. It does not search out
1614            through the entire recursion stack.
1615    
1616        (g) The escape \gN or \g{N} has been added, where N is a positive or
1617            negative number, specifying an absolute or relative reference.
1618    
1619    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1620        some "unreachable code" warnings.
1621    
1622    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1623        things, this adds five new scripts.
1624    
1625    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1626        There were also incompatibilities regarding the handling of \Q..\E inside
1627        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1628        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1629    
1630    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1631        matches an empty string, and forcibly breaks the loop. There were bugs in
1632        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1633        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1634        separate and independent bugs (that affected different cases) have been
1635        fixed.
1636    
1637    39. Refactored the code to abolish the use of different opcodes for small
1638        capturing bracket numbers. This is a tidy that I avoided doing when I
1639        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1640        The new approach is not only tidier, it makes it possible to reduce the
1641        memory needed to fix the previous bug (38).
1642    
1643    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1644        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1645        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1646        mode.
1647    
1648    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1649        report.
1650    
1651    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1652        copy construction and assignment in the C++ wrapper.
1653    
1654    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1655        couple of bugs that could have given wrong results in the "--newline=crlf"
1656        case.
1657    
1658    44. Added a number of casts and did some reorganization of signed/unsigned int
1659        variables following suggestions from Dair Grant. Also renamed the variable
1660        "this" as "item" because it is a C++ keyword.
1661    
1662    45. Arranged for dftables to add
1663    
1664          #include "pcre_internal.h"
1665    
1666        to pcre_chartables.c because without it, gcc 4.x may remove the array
1667        definition from the final binary if PCRE is built into a static library and
1668        dead code stripping is activated.
1669    
1670    46. For an unanchored pattern, if a match attempt fails at the start of a
1671        newline sequence, and the newline setting is CRLF or ANY, and the next two
1672        characters are CRLF, advance by two characters instead of one.
1673    
1674    
1675    Version 6.7 04-Jul-06
1676    ---------------------
1677    
1678     1. In order to handle tests when input lines are enormously long, pcretest has
1679        been re-factored so that it automatically extends its buffers when
1680        necessary. The code is crude, but this _is_ just a test program. The
1681        default size has been increased from 32K to 50K.
1682    
1683     2. The code in pcre_study() was using the value of the re argument before
1684        testing it for NULL. (Of course, in any sensible call of the function, it
1685        won't be NULL.)
1686    
1687     3. The memmove() emulation function in pcre_internal.h, which is used on
1688        systems that lack both memmove() and bcopy() - that is, hardly ever -
1689        was missing a "static" storage class specifier.
1690    
1691     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1692        containing an extended class (one that cannot be represented by a bitmap
1693        because it contains high-valued characters or Unicode property items, e.g.
1694        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1695        pattern, but PCRE should not loop if you do not (it no longer does).
1696        [Detail: two cases were found: (a) a repeated subpattern containing an
1697        extended class; (b) a recursive reference to a subpattern that followed a
1698        previous extended class. It wasn't skipping over the extended class
1699        correctly when UTF-8 mode was not set.]
1700    
1701     5. A negated single-character class was not being recognized as fixed-length
1702        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1703        compile error "lookbehind assertion is not fixed length".
1704    
1705     6. The RunPerlTest auxiliary script was showing an unexpected difference
1706        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1707        write a Perl script that can interpret lines of an input file either as
1708        byte characters or as UTF-8, which is what "perltest" was being required to
1709        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1710        can't do is switch easily at run time between having the "use utf8;" pragma
1711        or not. In the end, I fudged it by using the RunPerlTest script to insert
1712        "use utf8;" explicitly for the UTF-8 tests.
1713    
1714     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1715        the end of the subject string, contrary to the documentation and to what
1716        Perl does. This was true of both matching functions. Now it matches only at
1717        the start of the subject and immediately after *internal* newlines.
1718    
1719     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1720        a pointer to an int instead of a pointer to an unsigned long int. This
1721        caused problems on 64-bit systems.
1722    
1723     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1724        instance of the 'standard' template library not being so standard".
1725    
1726    10. There was no check on the number of named subpatterns nor the maximum
1727        length of a subpattern name. The product of these values is used to compute
1728        the size of the memory block for a compiled pattern. By supplying a very
1729        long subpattern name and a large number of named subpatterns, the size
1730        computation could be caused to overflow. This is now prevented by limiting
1731        the length of names to 32 characters, and the number of named subpatterns
1732        to 10,000.
1733    
1734    11. Subpatterns that are repeated with specific counts have to be replicated in
1735        the compiled pattern. The size of memory for this was computed from the
1736        length of the subpattern and the repeat count. The latter is limited to
1737        65535, but there was no limit on the former, meaning that integer overflow
1738        could in principle occur. The compiled length of a repeated subpattern is
1739        now limited to 30,000 bytes in order to prevent this.
1740    
1741    12. Added the optional facility to have named substrings with the same name.
1742    
1743    13. Added the ability to use a named substring as a condition, using the
1744        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1745        are numbers (not recommended). Forward references are permitted.
1746    
1747    14. Added forward references in named backreferences (if you see what I mean).
1748    
1749    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1750        pattern could run off the end of the subject. For example, the pattern
1751        "(?s)(.{1,5})"8 did this with the subject "ab".
1752    
1753    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1754        PCRE_CASELESS was set when matching characters that were quantified with ?
1755        or *.
1756    
1757    17. A character class other than a single negated character that had a minimum
1758        but no maximum quantifier - for example [ab]{6,} - was not handled
1759        correctly by pce_dfa_exec(). It would match only one character.
1760    
1761    18. A valid (though odd) pattern that looked like a POSIX character
1762        class but used an invalid character after [ (for example [[,abc,]]) caused
1763        pcre_compile() to give the error "Failed: internal error: code overflow" or
1764        in some cases to crash with a glibc free() error. This could even happen if
1765        the pattern terminated after [[ but there just happened to be a sequence of
1766        letters, a binary zero, and a closing ] in the memory that followed.
1767    
1768    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1769        over the years. Originally (before any Unicode support), just the bottom 8
1770        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1771        output from "man perlunicode" includes this:
1772    
1773          The regular expression compiler produces polymorphic opcodes.  That
1774          is, the pattern adapts to the data and automatically switches to
1775          the Unicode character scheme when presented with Unicode data--or
1776          instead uses a traditional byte scheme when presented with byte
1777          data.
1778    
1779        Sadly, a wide octal escape does not cause a switch, and in a string with
1780        no other multibyte characters, these octal escapes are treated as before.
1781        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1782        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1783        Unicode string.
1784    
1785        I have not perpetrated such confusion in PCRE. Up till now, it took just
1786        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1787        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1788        translate to the appropriate multibyte character.
1789    
1790    29. Applied some refactoring to reduce the number of warnings from Microsoft
1791        and Borland compilers. This has included removing the fudge introduced
1792        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1793        a warning about an unused variable.
1794    
1795    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1796        characters since release 4.0, because Perl (from release 5.004) does not.
1797        [Or at least, is documented not to: some releases seem to be in conflict
1798        with the documentation.] However, when a pattern was studied with
1799        pcre_study() and all its branches started with \s, PCRE still included VT
1800        as a possible starting character. Of course, this did no harm; it just
1801        caused an unnecessary match attempt.
1802    
1803    22. Removed a now-redundant internal flag bit that recorded the fact that case
1804        dependency changed within the pattern. This was once needed for "required
1805        byte" processing, but is no longer used. This recovers a now-scarce options
1806        bit. Also moved the least significant internal flag bit to the most-
1807        significant bit of the word, which was not previously used (hangover from
1808        the days when it was an int rather than a uint) to free up another bit for
1809        the future.
1810    
1811    23. Added support for CRLF line endings as well as CR and LF. As well as the
1812        default being selectable at build time, it can now be changed at runtime
1813        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1814        specify that it is scanning data with non-default line endings.
1815    
1816    24. Changed the definition of CXXLINK to make it agree with the definition of
1817        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1818    
1819    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1820        recursions. This makes a big different to stack usage for some patterns.
1821    
1822    26. If a subpattern containing a named recursion or subroutine reference such
1823        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1824        the space required for the compiled pattern went wrong and gave too small a
1825        value. Depending on the environment, this could lead to "Failed: internal
1826        error: code overflow at offset 49" or "glibc detected double free or
1827        corruption" errors.
1828    
1829    27. Applied patches from Google (a) to support the new newline modes and (b) to
1830        advance over multibyte UTF-8 characters in GlobalReplace.
1831    
1832    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1833        difference for some implementation of PCRE in some Windows version.
1834    
1835    29. Added some extra testing facilities to pcretest:
1836    
1837        \q<number>   in a data line sets the "match limit" value
1838        \Q<number>   in a data line sets the "match recursion limt" value
1839        -S <number>  sets the stack size, where <number> is in megabytes
1840    
1841        The -S option isn't available for Windows.
1842    
1843    
1844    Version 6.6 06-Feb-06
1845    ---------------------
1846    
1847     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1848        in pcreposix.h. I have copied the definition from pcre.h.
1849    
1850     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1851        because pcre.h is no longer a built file.
1852    
1853     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1854        not normally included in the compiled code.
1855    
1856    
1857    Version 6.5 01-Feb-06
1858    ---------------------
1859    
1860     1. When using the partial match feature with pcre_dfa_exec(), it was not
1861        anchoring the second and subsequent partial matches at the new starting
1862        point. This could lead to incorrect results. For example, with the pattern
1863        /1234/, partially matching against "123" and then "a4" gave a match.
1864    
1865     2. Changes to pcregrep:
1866    
1867        (a) All non-match returns from pcre_exec() were being treated as failures
1868            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1869            error message is output. Some extra information is given for the
1870            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1871            probably the only errors that are likely to be caused by users (by
1872            specifying a regex that has nested indefinite repeats, for instance).
1873            If there are more than 20 of these errors, pcregrep is abandoned.
1874    
1875        (b) A binary zero was treated as data while matching, but terminated the
1876            output line if it was written out. This has been fixed: binary zeroes
1877            are now no different to any other data bytes.
1878    
1879        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1880            used to set a locale for matching. The --locale=xxxx long option has
1881            been added (no short equivalent) to specify a locale explicitly on the
1882            pcregrep command, overriding the environment variables.
1883    
1884        (d) When -B was used with -n, some line numbers in the output were one less
1885            than they should have been.
1886    
1887        (e) Added the -o (--only-matching) option.
1888    
1889        (f) If -A or -C was used with -c (count only), some lines of context were
1890            accidentally printed for the final match.
1891    
1892        (g) Added the -H (--with-filename) option.
1893    
1894        (h) The combination of options -rh failed to suppress file names for files
1895            that were found from directory arguments.
1896    
1897        (i) Added the -D (--devices) and -d (--directories) options.
1898    
1899        (j) Added the -F (--fixed-strings) option.
1900    
1901        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1902    
1903        (l) Added the --colo(u)r option.
1904    
1905        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1906            is not present by default.
1907    
1908     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1909        items such as (?R) or (?1), when the recursion could match a number of
1910        alternatives. If it matched one of the alternatives, but subsequently,
1911        outside the recursion, there was a failure, the code tried to back up into
1912        the recursion. However, because of the way PCRE is implemented, this is not
1913        possible, and the result was an incorrect result from the match.
1914    
1915        In order to prevent this happening, the specification of recursion has
1916        been changed so that all such subpatterns are automatically treated as
1917        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1918    
1919     4. I had overlooked the fact that, in some locales, there are characters for
1920        which isalpha() is true but neither isupper() nor islower() are true. In
1921        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1922        and ordfeminine) are like this. This affected the treatment of \w and \W
1923        when they appeared in character classes, but not when they appeared outside
1924        a character class. The bit map for "word" characters is now created
1925        separately from the results of isalnum() instead of just taking it from the
1926        upper, lower, and digit maps. (Plus the underscore character, of course.)
1927    
1928     5. The above bug also affected the handling of POSIX character classes such as
1929        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1930        permanent tables. Instead, the bit maps for such a class were previously
1931        created as the appropriate unions of the upper, lower, and digit bitmaps.
1932        Now they are created by subtraction from the [[:word:]] class, which has
1933        its own bitmap.
1934    
1935     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1936        It is created by subtracting the vertical space characters (\x09, \x0a,
1937        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1938        subtraction was done in the overall bitmap for a character class, meaning
1939        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1940        be recognized. This bug has been fixed.
1941    
1942     7. Patches from the folks at Google:
1943    
1944          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1945          real life, but is still worth protecting against".
1946    
1947          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1948          regular expressions".
1949    
1950          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1951          have it.
1952    
1953          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1954          "configure" and the latter not, in order to fix a problem somebody had
1955          with compiling the Arg class on HP-UX.
1956    
1957          (e) Improve the error-handling of the C++ wrapper a little bit.
1958    
1959          (f) New tests for checking recursion limiting.
1960    
1961     8. The pcre_memmove() function, which is used only if the environment does not
1962        have a standard memmove() function (and is therefore rarely compiled),
1963        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1964        returning a result (though PCRE never actually uses the result).
1965    
1966     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1967        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1968        returned instead of calling malloc() with an overflowing number that would
1969        most likely cause subsequent chaos.
1970    
1971    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1972    
1973    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1974        with this option is matched, the nmatch and pmatch options of regexec() are
1975        ignored.
1976    
1977    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1978        provided in case anyone wants to the the POSIX interface with UTF-8
1979        strings.
1980    
1981    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1982        C++ linking (needed for some HP-UX environments).
1983    
1984    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1985        (unused parameter) and in the pcre_printint() function (omitted "default"
1986        switch label when the default is to do nothing).
1987    
1988    15. Added some code to make it possible, when PCRE is compiled as a C++
1989        library, to replace subject pointers for pcre_exec() with a smart pointer
1990        class, thus making it possible to process discontinuous strings.
1991    
1992    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1993        much the same function. They were added by different people who were trying
1994        to make PCRE easy to compile on non-Unix systems. It has been suggested
1995        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1996        for compiling on Windows systems. I have therefore replaced it with
1997        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1998        defaults to "extern" for C or "extern C" for C++, which works fine on
1999        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2000        SCOPE with something explicit in config.h. In addition:
2001    
2002        (a) pcreposix.h still had just "extern" instead of either of these macros;
2003            I have replaced it with PCRE_DATA_SCOPE.
2004    
2005        (b) Functions such as _pcre_xclass(), which are internal to the library,
2006            but external in the C sense, all had PCRE_EXPORT in their definitions.
2007            This is apparently wrong for the Windows case, so I have removed it.
2008            (It makes no difference on Unix-like systems.)
2009    
2010    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2011        of recursive calls to match(). This is different to MATCH_LIMIT because
2012        that limits the total number of calls to match(), not all of which increase
2013        the depth of recursion. Limiting the recursion depth limits the amount of
2014        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2015        when PCRE is compiled, and changed at run time. A patch from Google adds
2016        this functionality to the C++ interface.
2017    
2018    18. Changes to the handling of Unicode character properties:
2019    
2020        (a) Updated the table to Unicode 4.1.0.
2021    
2022        (b) Recognize characters that are not in the table as "Cn" (undefined).
2023    
2024        (c) I revised the way the table is implemented to a much improved format
2025            which includes recognition of ranges. It now supports the ranges that
2026            are defined in UnicodeData.txt, and it also amalgamates other
2027            characters into ranges. This has reduced the number of entries in the
2028            table from around 16,000 to around 3,000, thus reducing its size
2029            considerably. I realized I did not need to use a tree structure after
2030            all - a binary chop search is just as efficient. Having reduced the
2031            number of entries, I extended their size from 6 bytes to 8 bytes to
2032            allow for more data.
2033    
2034        (d) Added support for Unicode script names via properties such as \p{Han}.
2035    
2036    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2037        matching that character.
2038    
2039    20. When matching a repeated Unicode property with a minimum greater than zero,
2040        (for example \pL{2,}), PCRE could look past the end of the subject if it
2041        reached it while seeking the minimum number of characters. This could
2042        happen only if some of the characters were more than one byte long, because
2043        there is a check for at least the minimum number of bytes.
2044    
2045    21. Refactored the implementation of \p and \P so as to be more general, to
2046        allow for more different types of property in future. This has changed the
2047        compiled form incompatibly. Anybody with saved compiled patterns that use
2048        \p or \P will have to recompile them.
2049    
2050    22. Added "Any" and "L&" to the supported property types.
2051    
2052    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2053        but give a compile time error if the value is greater than 0xff.
2054    
2055    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2056        accidentally not being installed or uninstalled.
2057    
2058    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2059        made were to insert the current release number. This seemed silly, because
2060        it made things harder for people building PCRE on systems that don't run
2061        "configure". I have turned pcre.h into a distributed file, no longer built
2062        by "configure", with the version identification directly included. There is
2063        no longer a pcre.h.in file.
2064    
2065        However, this change necessitated a change to the pcre-config script as
2066        well. It is built from pcre-config.in, and one of the substitutions was the
2067        release number. I have updated configure.ac so that ./configure now finds
2068        the release number by grepping pcre.h.
2069    
2070    26. Added the ability to run the tests under valgrind.
2071    
2072    
2073    Version 6.4 05-Sep-05
2074    ---------------------
2075    
2076     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2077        "--" to be printed when multiple files were scanned, even when none of the
2078        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2079        consider it to be a bug, and have restored the previous behaviour.
2080    
2081     2. A couple of code tidies to get rid of compiler warnings.
2082    
2083     3. The pcretest program used to cheat by referring to symbols in the library
2084        whose names begin with _pcre_. These are internal symbols that are not
2085        really supposed to be visible externally, and in some environments it is
2086        possible to suppress them. The cheating is now confined to including
2087        certain files from the library's source, which is a bit cleaner.
2088    
2089     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2090        file's purpose clearer.
2091    
2092     5. Reorganized pcre_ucp_findchar().
2093    
2094    
2095    Version 6.3 15-Aug-05
2096    ---------------------
2097    
2098     1. The file libpcre.pc.in did not have general read permission in the tarball.
2099    
2100     2. There were some problems when building without C++ support:
2101    
2102        (a) If C++ support was not built, "make install" and "make test" still
2103            tried to test it.
2104    
2105        (b) There were problems when the value of CXX was explicitly set. Some
2106            changes have been made to try to fix these, and ...
2107    
2108        (c) --disable-cpp can now be used to explicitly disable C++ support.
2109    
2110        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2111            backslash in a target when C++ was disabled. This confuses some
2112            versions of "make", apparently. Using an intermediate variable solves
2113            this. (Same for CPP_LOBJ.)
2114    
2115     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2116        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2117        necessary on certain architectures.
2118    
2119     4. Added a setting of -export-symbols-regex to the link command to remove
2120        those symbols that are exported in the C sense, but actually are local
2121        within the library, and not documented. Their names all begin with
2122        "_pcre_". This is not a perfect job, because (a) we have to except some
2123        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2124        available (and never for static libraries). I have made a note to try to
2125        find a way round (a) in the future.
2126    
2127    
2128    Version 6.2 01-Aug-05
2129    ---------------------
2130    
2131     1. There was no test for integer overflow of quantifier values. A construction
2132        such as {1111111111111111} would give undefined results. What is worse, if
2133        a minimum quantifier for a parenthesized subpattern overflowed and became
2134        negative, the calculation of the memory size went wrong. This could have
2135        led to memory overwriting.
2136    
2137     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2138    
2139     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2140        operating environments where this matters.
2141    
2142     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2143        PCRE options from within the C++ wrapper.
2144    
2145     5. Named capturing subpatterns were not being correctly counted when a pattern
2146        was compiled. This caused two problems: (a) If there were more than 100
2147        such subpatterns, the calculation of the memory needed for the whole
2148        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2149        back references of the form \12, where the number was greater than 9, were
2150        not recognized as back references, even though there were sufficient
2151        previous subpatterns.
2152    
2153     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2154        versions of gcc, e.g. 2.95.4.
2155    
2156    
2157    Version 6.1 21-Jun-05
2158    ---------------------
2159    
2160     1. There was one reference to the variable "posix" in pcretest.c that was not
2161        surrounded by "#if !defined NOPOSIX".
2162    
2163     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2164        the cross-check on the old pcre_info() function, for the benefit of the
2165        cut-down version of PCRE that is currently imported into Exim.
2166    
2167     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2168        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2169        patterns that start (?i) but I don't think that matters. The use of (?i) is
2170        just an example; this all applies to the other options as well.
2171    
2172     4. Since libtool seems to echo the compile commands it is issuing, the output
2173        from "make" can be reduced a bit by putting "@" in front of each libtool
2174        compile command.
2175    
2176     5. Patch from the folks at Google for configure.in to be a bit more thorough
2177        in checking for a suitable C++ installation before trying to compile the
2178        C++ stuff. This should fix a reported problem when a compiler was present,
2179        but no suitable headers.
2180    
2181     6. The man pages all had just "PCRE" as their title. I have changed them to
2182        be the relevant file name. I have also arranged that these names are
2183        retained in the file doc/pcre.txt, which is a concatenation in text format
2184        of all the man pages except the little individual ones for each function.
2185    
2186     7. The NON-UNIX-USE file had not been updated for the different set of source
2187        files that come with release 6. I also added a few comments about the C++
2188        wrapper.
2189    
2190    
2191    Version 6.0 07-Jun-05
2192    ---------------------
2193    
2194     1. Some minor internal re-organization to help with my DFA experiments.
2195    
2196     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2197        didn't matter for the library itself when fully configured, but did matter
2198        when compiling without UCP support, or within Exim, where the ucp files are
2199        not imported.
2200    
2201     3. Refactoring of the library code to split up the various functions into
2202        different source modules. The addition of the new DFA matching code (see
2203        below) to a single monolithic source would have made it really too
2204        unwieldy, quite apart from causing all the code to be include in a
2205        statically linked application, when only some functions are used. This is
2206        relevant even without the DFA addition now that patterns can be compiled in
2207        one application and matched in another.
2208    
2209        The downside of splitting up is that there have to be some external
2210        functions and data tables that are used internally in different modules of
2211        the library but which are not part of the API. These have all had their
2212        names changed to start with "_pcre_" so that they are unlikely to clash
2213        with other external names.
2214    
2215     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2216        a different (DFA) algorithm. Although it is slower than the original
2217        function, it does have some advantages for certain types of matching
2218        problem.
2219    
2220     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2221        including restarting after a partial match.
2222    
2223     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2224        defined when compiling for Windows was sent to me. I have put it into the
2225        code, though I have no means of testing or verifying it.
2226    
2227     7. Added the pcre_refcount() auxiliary function.
2228    
2229     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2230        match before or at the first newline in the subject string. In pcretest,
2231        the /f option on a pattern can be used to set this.
2232    
2233     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2234        would behave wrongly. This has been present in PCRE since release 4.0.
2235    
2236    10. A number of changes to the pcregrep command:
2237    
2238        (a) Refactored how -x works; insert ^(...)$ instead of setting
2239            PCRE_ANCHORED and checking the length, in preparation for adding
2240            something similar for -w.
2241    
2242        (b) Added the -w (match as a word) option.
2243    
2244        (c) Refactored the way lines are read and buffered so as to have more
2245            than one at a time available.
2246    
2247        (d) Implemented a pcregrep test script.
2248    
2249        (e) Added the -M (multiline match) option. This allows patterns to match
2250            over several lines of the subject. The buffering ensures that at least
2251            8K, or the rest of the document (whichever is the shorter) is available
2252            for matching (and similarly the previous 8K for lookbehind assertions).
2253    
2254        (f) Changed the --help output so that it now says
2255    
2256              -w, --word-regex(p)
2257    
2258            instead of two lines, one with "regex" and the other with "regexp"
2259            because that confused at least one person since the short forms are the
2260            same. (This required a bit of code, as the output is generated
2261            automatically from a table. It wasn't just a text change.)
2262    
2263        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2264            option but starts with a hyphen. Could be a pattern or a path name
2265            starting with a hyphen, for instance.
2266    
2267        (h) "-" can be given as a file name to represent stdin.
2268    
2269        (i) When file names are being printed, "(standard input)" is used for
2270            the standard input, for compatibility with GNU grep. Previously
2271            "<stdin>" was used.
2272    
2273        (j) The option --label=xxx can be used to supply a name to be used for
2274            stdin when file names are being printed. There is no short form.
2275    
2276        (k) Re-factored the options decoding logic because we are going to add
2277            two more options that take data. Such options can now be given in four
2278            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2279    
2280        (l) Added the -A, -B, and -C options for requesting that lines of context
2281            around matches be printed.
2282    
2283        (m) Added the -L option to print the names of files that do not contain
2284            any matching lines, that is, the complement of -l.
2285    
2286        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2287            continue to scan other files.
2288    
2289        (o) The -s option was incorrectly implemented. For compatibility with other
2290            greps, it now suppresses the error message for a non-existent or non-
2291            accessible file (but not the return code). There is a new option called
2292            -q that suppresses the output of matching lines, which was what -s was
2293            previously doing.
2294    
2295        (p) Added --include and --exclude options to specify files for inclusion
2296            and exclusion when recursing.
2297    
2298    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2299        Hopefully, it now does.
2300    
2301    12. Missing cast in pcre_study().
2302    
2303    13. Added an "uninstall" target to the makefile.
2304    
2305    14. Replaced "extern" in the function prototypes in Makefile.in with
2306        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2307        world, but is set differently for Windows.
2308    
2309    15. Added a second compiling function called pcre_compile2(). The only
2310        difference is that it has an extra argument, which is a pointer to an
2311        integer error code. When there is a compile-time failure, this is set
2312        non-zero, in addition to the error test pointer being set to point to an
2313        error message. The new argument may be NULL if no error number is required
2314        (but then you may as well call pcre_compile(), which is now just a
2315        wrapper). This facility is provided because some applications need a
2316        numeric error indication, but it has also enabled me to tidy up the way
2317        compile-time errors are handled in the POSIX wrapper.
2318    
2319    16. Added VPATH=.libs to the makefile; this should help when building with one
2320        prefix path and installing with another. (Or so I'm told by someone who
2321        knows more about this stuff than I do.)
2322    
2323    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2324        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2325        match everything, including newlines. This is not POSIX-compatible, but
2326        somebody wanted the feature. From pcretest it can be activated by using
2327        both the P and the s flags.
2328    
2329    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2330    
2331    19. libpcre.pc was being incorrectly installed as executable.
2332    
2333    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2334        it now also looks for '\r' so that it will work unmodified on Windows.
2335    
2336    21. Added Google's contributed C++ wrapper to the distribution.
2337    
2338    22. Added some untidy missing memory free() calls in pcretest, to keep
2339        Electric Fence happy when testing.
2340    
2341    
2342    
2343    Version 5.0 13-Sep-04
2344    ---------------------
2345    
2346     1. Internal change: literal characters are no longer packed up into items
2347        containing multiple characters in a single byte-string. Each character
2348        is now matched using a separate opcode. However, there may be more than one
2349        byte in the character in UTF-8 mode.
2350    
2351     2. The pcre_callout_block structure has two new fields: pattern_position and
2352        next_item_length. These contain the offset in the pattern to the next match
2353        item, and its length, respectively.
2354    
2355     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2356        insertion of callouts before each pattern item. Added the /C option to
2357        pcretest to make use of this.
2358    
2359     4. On the advice of a Windows user, the lines
2360    
2361          #if defined(_WIN32) || defined(WIN32)
2362          _setmode( _fileno( stdout ), 0x8000 );
2363          #endif  /* defined(_WIN32) || defined(WIN32) */
2364    
2365        have been added to the source of pcretest. This apparently does useful
2366        magic in relation to line terminators.
2367    
2368     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2369        for the benefit of those environments where the "b" makes a difference.
2370    
2371     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2372        to know about it. I have put a hack into configure.in that adds in code
2373        to set GCC=yes if CC=icc. This seems to end up at a point in the
2374        generated configure script that is early enough to affect the setting of
2375        compiler options, which is what is needed, but I have no means of testing
2376        whether it really works. (The user who reported this had patched the
2377        generated configure script, which of course I cannot do.)
2378    
2379        LATER: After change 22 below (new libtool files), the configure script
2380        seems to know about icc (and also ecc). Therefore, I have commented out
2381        this hack in configure.in.
2382    
2383     7. Added support for pkg-config (2 patches were sent in).
2384    
2385     8. Negated POSIX character classes that used a combination of internal tables
2386        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2387        [[:^ascii]]. Typically, they would match almost any characters. The other
2388        POSIX classes were not broken in this way.
2389    
2390     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2391        to find the match, as PCRE was deluded into thinking that the match had to
2392        start at the start point or following a newline. The same bug applied to
2393        patterns with negative forward assertions or any backward assertions
2394        preceding ".*" at the start, unless the pattern required a fixed first
2395        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2396    
2397    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2398        starting at the last subject character, bytes beyond the end of the subject
2399        string were read.
2400    
2401    11. Renamed the variable "class" as "classbits" to make life easier for C++
2402        users. (Previously there was a macro definition, but it apparently wasn't
2403        enough.)
2404    
2405    12. Added the new field "tables" to the extra data so that tables can be passed
2406        in at exec time, or the internal tables can be re-selected. This allows
2407        a compiled regex to be saved and re-used at a later time by a different
2408        program that might have everything at different addresses.
2409    
2410    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2411        -R library as well as a -L library.
2412    
2413    14. The debugging options of pcretest (-d on the command line or D on a
2414        pattern) showed incorrect output for anything following an extended class
2415        that contained multibyte characters and which was followed by a quantifier.
2416    
2417    15. Added optional support for general category Unicode character properties
2418        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2419        support. It adds about 90K to the size of the library. The meanings of the
2420        inbuilt class escapes such as \d and \s have NOT been changed.
2421    
2422    16. Updated pcredemo.c to include calls to free() to release the memory for the
2423        compiled pattern.
2424    
2425    17. The generated file chartables.c was being created in the source directory
2426        instead of in the building directory. This caused the build to fail if the
2427        source directory was different from the building directory, and was
2428        read-only.
2429    
2430    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2431        file. No doubt somebody will tell me if they don't make sense... Also added
2432        Dan Mooney's comments about building on OpenVMS.
2433    
2434    19. Added support for partial matching via the PCRE_PARTIAL option for
2435        pcre_exec() and the \P data escape in pcretest.
2436    
2437    20. Extended pcretest with 3 new pattern features:
2438    
2439        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2440              write the compiled pattern to the file whose name is "rest-of-line".
2441              This is a straight binary dump of the data, with the saved pointer to
2442              the character tables forced to be NULL. The study data, if any, is
2443              written too. After writing, pcretest reads a new pattern.
2444    
2445        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2446              compiled pattern from the given file. There must not be any
2447              occurrences of "<" in the file name (pretty unlikely); if there are,
2448              pcretest will instead treat the initial "<" as a pattern delimiter.
2449              After reading in the pattern, pcretest goes on to read data lines as
2450              usual.
2451    
2452        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2453              and 16-bit fields in a compiled pattern, to simulate a pattern that
2454              was compiled on a host of opposite endianness.
2455    
2456    21. The pcre-exec() function can now cope with patterns that were compiled on
2457        hosts of opposite endianness, with this restriction:
2458    
2459          As for any compiled expression that is saved and used later, the tables
2460          pointer field cannot be preserved; the extra_data field in the arguments
2461          to pcre_exec() should be used to pass in a tables address if a value
2462          other than the default internal tables were used at compile time.
2463    
2464    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2465        now diagnosed as an error. Previously, most of the time, a negative number
2466        would have been treated as zero, but if in addition "ovector" was passed as
2467        NULL, a crash could occur.
2468    
2469    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2470        new versions from the libtool 1.5 distribution (the last one is a copy of
2471        a file called libtool.m4). This seems to have fixed the need to patch
2472        "configure" to support Darwin 1.3 (which I used to do). However, I still
2473        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2474        workstation).
2475    
2476    24. Changed the PCRE licence to be the more standard "BSD" licence.
2477    
2478    
2479    Version 4.5 01-Dec-03
2480    ---------------------
2481    
2482     1. There has been some re-arrangement of the code for the match() function so
2483        that it can be compiled in a version that does not call itself recursively.
2484        Instead, it keeps those local variables that need separate instances for
2485        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2486        needs to "recurse". Keeping track of where control must go is done by means
2487        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2488        hide most of the details from the main code, and operates only if
2489        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2490        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2491        operating.
2492    
2493        To make it easier for callers to provide specially tailored get/free
2494        functions for this usage, two new functions, pcre_stack_malloc, and
2495        pcre_stack_free, are used. They are always called in strict stacking order,
2496        and the size of block requested is always the same.
2497    
2498        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2499        PCRE has been compiled to use the stack or the heap for recursion. The
2500        -C option of pcretest uses this to show which version is compiled.
2501    
2502        A new data escape \S, is added to pcretest; it causes the amounts of store
2503        obtained and freed by both kinds of malloc/free at match time to be added
2504        to the output.
2505    
2506     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2507        what's available on my current Linux desktop machine.
2508    
2509     3. When matching a UTF-8 string, the test for a valid string at the start has
2510        been extended. If start_offset is not zero, PCRE now checks that it points
2511        to a byte that is the start of a UTF-8 character. If not, it returns
2512        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2513        this is necessary because there may be backward assertions in the pattern.
2514        When matching the same subject several times, it may save resources to use
2515        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2516    
2517     4. The code for checking the validity of UTF-8 strings has been tightened so
2518        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2519        containing "overlong sequences".
2520    
2521     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2522        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2523        should have been "&", but it just so happened that all the cases this let
2524        through by mistake were picked up later in the function.
2525    
2526     6. I had used a variable called "isblank" - this is a C99 function, causing
2527        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2528    
2529     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2530        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2531        so the version is shown; (c) stop "make test" echoing "./RunTest".
2532    
2533     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2534    
2535     9. The prototype for memmove() for systems that don't have it was using
2536        size_t, but the inclusion of the header that defines size_t was later. I've
2537        moved the #includes for the C headers earlier to avoid this.
2538    
2539    10. Added some adjustments to the code to make it easier to compiler on certain
2540        special systems:
2541    
2542          (a) Some "const" qualifiers were missing.
2543          (b) Added the macro EXPORT before all exported functions; by default this
2544              is defined to be empty.
2545          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2546              that it reads its output file name as an argument instead of writing
2547              to the standard output and assuming this can be redirected.
2548    
2549    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2550        class containing characters with values greater than 255, PCRE compilation
2551        went into a loop.
2552    
2553    12. A recursive reference to a subpattern that was within another subpattern
2554        that had a minimum quantifier of zero caused PCRE to crash. For example,
2555        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2556        recursion. If the recursively-called subpattern itself had a zero repeat,
2557        that was OK.
2558    
2559    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2560        buffer into which it was copied (for escape processing) was still set at
2561        1024, so long lines caused crashes.
2562    
2563    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2564        "internal error: code overflow...". This applied to any character class
2565        that was followed by a possessive quantifier.
2566    
2567    15. Modified the Makefile to add libpcre.la as a prerequisite for
2568        libpcreposix.la because I was told this is needed for a parallel build to
2569        work.
2570    
2571    16. If a pattern that contained .* following optional items at the start was
2572        studied, the wrong optimizing data was generated, leading to matching
2573        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2574        matching string must start with a or b or c. The correct conclusion for
2575        this pattern is that a match can start with any character.
2576    
2577    
2578    Version 4.4 13-Aug-03
2579    ---------------------
2580    
2581     1. In UTF-8 mode, a character class containing characters with values between
2582        127 and 255 was not handled correctly if the compiled pattern was studied.
2583        In fixing this, I have also improved the studying algorithm for such
2584        classes (slightly).
2585    
2586     2. Three internal functions had redundant arguments passed to them. Removal
2587        might give a very teeny performance improvement.
2588    
2589     3. Documentation bug: the value of the capture_top field in a callout is *one
2590        more than* the number of the hightest numbered captured substring.
2591    
2592     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2593        in incorrectly linking with a previously installed version. They now link
2594        explicitly with libpcre.la.
2595    
2596     5. configure.in no longer needs to recognize Cygwin specially.
2597    
2598     6. A problem in pcre.in for Windows platforms is fixed.
2599    
2600     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2601        pcretest, it used to include the size of the study block as part of its
2602        output. Unfortunately, the structure contains a field that has a different
2603        size on different hardware architectures. This meant that the tests that
2604        showed this size failed. As the block is currently always of a fixed size,
2605        this information isn't actually particularly useful in pcretest output, so
2606        I have just removed it.
2607    
2608     8. Three pre-processor statements accidentally did not start in column 1.
2609        Sadly, there are *still* compilers around that complain, even though
2610        standard C has not required this for well over a decade. Sigh.
2611    
2612     9. In pcretest, the code for checking callouts passed small integers in the
2613        callout_data field, which is a void * field. However, some picky compilers
2614        complained about the casts involved for this on 64-bit systems. Now
2615        pcretest passes the address of the small integer instead, which should get
2616        rid of the warnings.
2617    
2618    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2619        both compile and run time, and gives an error if an invalid UTF-8 sequence
2620        is found. There is a option for disabling this check in cases where the
2621        string is known to be correct and/or the maximum performance is wanted.
2622    
2623    11. In response to a bug report, I changed one line in Makefile.in from
2624    
2625            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2626        to
2627            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2628    
2629        to look similar to other lines, but I have no way of telling whether this
2630        is the right thing to do, as I do not use Windows. No doubt I'll get told
2631        if it's wrong...
2632    
2633    
2634    Version 4.3 21-May-03
2635    ---------------------
2636    
2637    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2638       Makefile.
2639    
2640    2. Some refactoring to improve the quality of the code:
2641    
2642       (i)   The utf8_table... variables are now declared "const".
2643    
2644       (ii)  The code for \cx, which used the "case flipping" table to upper case
2645             lower case letters, now just substracts 32. This is ASCII-specific,
2646             but the whole concept of \cx is ASCII-specific, so it seems
2647             reasonable.
2648    
2649       (iii) PCRE was using its character types table to recognize decimal and
2650             hexadecimal digits in the pattern. This is silly, because it handles
2651             only 0-9, a-f, and A-F, but the character types table is locale-
2652             specific, which means strange things might happen. A private
2653             table is now used for this - though it costs 256 bytes, a table is
2654             much faster than multiple explicit tests. Of course, the standard
2655             character types table is still used for matching digits in subject
2656             strings against \d.
2657    
2658       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2659             ending in _t are). So I've renamed it as ESC_tee.
2660    
2661    3. The first argument for regexec() in the POSIX wrapper should have been
2662       defined as "const".
2663    
2664    4. Changed pcretest to use malloc() for its buffers so that they can be
2665       Electric Fenced for debugging.
2666    
2667    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2668       to read one or more bytes before the start of the subject string. Often this
2669       had no effect on PCRE's behaviour, but in some circumstances it could
2670       provoke a segmentation fault.
2671    
2672    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2673       to try to read one or more bytes before the start of the subject string.
2674    
2675    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2676       UTF-8 support could misbehave in various ways if the subject string
2677       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2678       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2679       back over UTF-8 characters.)
2680    
2681    
2682    Version 4.2 14-Apr-03
2683    ---------------------
2684    
2685    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2686    
2687    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2688         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2689         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2690         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2691         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2692           and BUILD_EXEEXT
2693         Note: automatic setting of the BUILD variables is not yet working
2694         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2695           compile-time but not at link-time
2696         [LINK]: use for linking executables only
2697         make different versions for Windows and non-Windows
2698         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2699           libraries
2700         [LINK_FOR_BUILD]: new variable
2701         [OBJEXT]: use throughout
2702         [EXEEXT]: use throughout
2703         <winshared>: new target
2704         <wininstall>: new target
2705         <dftables.o>: use native compiler
2706         <dftables>: use native linker
2707         <install>: handle Windows platform correctly
2708         <clean>: ditto
2709         <check>: ditto
2710         copy DLL to top builddir before testing
2711    
2712       As part of these changes, -no-undefined was removed again. This was reported
2713       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2714       in any case.
2715    
2716    3. Some tidies to get rid of compiler warnings:
2717    
2718       . In the match_data structure, match_limit was an unsigned long int, whereas
2719         match_call_count was an int. I've made them both unsigned long ints.
2720    
2721       . In pcretest the fact that a const uschar * doesn't automatically cast to
2722         a void * provoked a warning.
2723    
2724       . Turning on some more compiler warnings threw up some "shadow" variables
2725         and a few more missing casts.
2726    
2727    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2728       option, a class that contained a single character with a value between 128
2729       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2730    
2731    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2732       option, a class that contained several characters, but with at least one
2733       whose value was between 128 and 255 caused PCRE to crash.
2734    
2735    
2736    Version 4.1 12-Mar-03
2737    ---------------------
2738    
2739    1. Compiling with gcc -pedantic found a couple of places where casts were
2740    needed, and a string in dftables.c that was longer than standard compilers are
2741    required to support.
2742    
2743    2. Compiling with Sun's compiler found a few more places where the code could
2744    be tidied up in order to avoid warnings.
2745    
2746    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2747    first of these names is deprecated in the latest Autoconf in favour of the name
2748    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2749    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2750    analogy I have changed it to CFLAGS_FOR_BUILD.
2751    
2752    4. Added -no-undefined to the linking command in the Makefile, because this is
2753    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2754    linking step for the pcreposix library.
2755    
2756    5. PCRE was failing to diagnose the case of two named groups with the same
2757    name.
2758    
2759    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2760    literal character that is needed in the subject for a match, and scans along to
2761    ensure that it is present before embarking on the full matching process. This
2762    saves time in cases of nested unlimited repeats that are never going to match.
2763    Problem: the scan can take a lot of time if the subject is very long (e.g.
2764    megabytes), thus penalizing straightforward matches. It is now done only if the
2765    amount of subject to be scanned is less than 1000 bytes.
2766    
2767    7. A lesser problem with the same optimization is that it was recording the
2768    first character of an anchored pattern as "needed", thus provoking a search
2769    right along the subject, even when the first match of the pattern was going to
2770    fail. The "needed" character is now not set for anchored patterns, unless it
2771    follows something in the pattern that is of non-fixed length. Thus, it still
2772    fulfils its original purpose of finding quick non-matches in cases of nested
2773    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2774    
2775    
2776    Version 4.0 17-Feb-03
2777    ---------------------
2778    
2779    1. If a comment in an extended regex that started immediately after a meta-item
2780    extended to the end of string, PCRE compiled incorrect data. This could lead to
2781    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2782    
2783    2. Moved to autoconf 2.53 and libtool 1.4.2.
2784    
2785    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2786    the special perltest8 script is no longer needed - all the tests can be run
2787    from a single perltest script.
2788    
2789    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2790    by \s. It has now been removed in PCRE. This means it isn't recognized as
2791    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2792    class [:space:] *does* include VT, thereby creating a mess.
2793    
2794    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2795    space and tab.
2796    
2797    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2798    its new features into the main test script, reducing the number of scripts.
2799    
2800    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2801    were backward compatible, and made the (?i) apply to the whole pattern, as if
2802    /i were given. Now it behaves more logically, and applies the option setting
2803    only to what follows. PCRE has been changed to follow suit. However, if it
2804    finds options settings right at the start of the pattern, it extracts them into
2805    the global options, as before. Thus, they show up in the info data.
2806    
2807    8. Added support for the \Q...\E escape sequence. Characters in between are
2808    treated as literals. This is slightly different from Perl in that $ and @ are
2809    also handled as literals inside the quotes. In Perl, they will cause variable
2810    interpolation. Note the following examples:
2811    
2812        Pattern            PCRE matches      Perl matches
2813    
2814        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2815        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2816        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2817    
2818    For compatibility with Perl, \Q...\E sequences are recognized inside character
2819    classes as well as outside them.
2820    
2821    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2822    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2823    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2824    signed/unsigned warnings.
2825    
2826    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2827    option for pcretest, so I've replaced it by a simple function that does just
2828    that job.
2829    
2830    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2831    "pcregrep -".
2832    
2833    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2834    Java package. This provides some syntactic sugar for simple cases of what my
2835    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2836    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2837    item, you can use this simplified notation. Note that only makes sense with
2838    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2839    greediness, whatever the setting of the PCRE_UNGREEDY option.
2840    
2841    13. A change of greediness default within a pattern was not taking effect at
2842    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2843    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2844    was abstracted outside.
2845    
2846    14. PCRE now supports the \G assertion. It is true when the current matching
2847    position is at the start point of the match. This differs from \A when the
2848    starting offset is non-zero. Used with the /g option of pcretest (or similar
2849    code), it works in the same way as it does for Perl's /g option. If all
2850    alternatives of a regex begin with \G, the expression is anchored to the start
2851    match position, and the "anchored" flag is set in the compiled expression.
2852    
2853    15. Some bugs concerning the handling of certain option changes within patterns
2854    have been fixed. These applied to options other than (?ims). For example,
2855    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2856    been the other way round. Some of this was related to change 7 above.
2857    
2858    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2859    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2860    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2861    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2862    
2863    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2864    mode. Unlike ".", it always matches newline, whatever the setting of
2865    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2866    assertions. Perl allows it, but it doesn't (in general) work because it can't
2867    calculate the length of the lookbehind. At least, that's the case for Perl
2868    5.8.0 - I've been told they are going to document that it doesn't work in
2869    future.
2870    
2871    18. Added an error diagnosis for escapes that PCRE does not support: these are
2872    \L, \l, \N, \P, \p, \U, \u, and \X.
2873    
2874    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2875    reading past the end of the pattern in cases such as /[abcd/.
2876    
2877    20. PCRE was getting more memory than necessary for patterns with classes that
2878    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2879    
2880    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2881    compiling PCRE for use with Virtual Pascal.
2882    
2883    22. Small fix to the Makefile to make it work properly if the build is done
2884    outside the source tree.
2885    
2886    23. Added a new extension: a condition to go with recursion. If a conditional
2887    subpattern starts with (?(R) the "true" branch is used if recursion has
2888    happened, whereas the "false" branch is used only at the top level.
2889    
2890    24. When there was a very long string of literal characters (over 255 bytes
2891    without UTF support, over 250 bytes with UTF support), the computation of how
2892    much memory was required could be incorrect, leading to segfaults or other
2893    strange effects.
2894    
2895    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2896    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2897    there was a subsequent back reference to those brackets. This meant that, for
2898    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2899    possible to check for precisely this case. All we can do is abandon the
2900    optimization if .* occurs inside capturing brackets when there are any back
2901    references whatsoever. (See below for a better fix that came later.)
2902    
2903    26. The handling of the optimization for finding the first character of a
2904    non-anchored pattern, and for finding a character that is required later in the
2905    match were failing in some cases. This didn't break the matching; it just
2906    failed to optimize when it could. The way this is done has been re-implemented.
2907    
2908    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2909    
2910    28. Added a new feature that provides some of the functionality that Perl
2911    provides with (?{...}). The facility is termed a "callout". The way it is done
2912    in PCRE is for the caller to provide an optional function, by setting
2913    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2914    global variable. By default it is unset, which disables all calling out. To get
2915    the function called, the regex must include (?C) at appropriate points. This
2916    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2917    This provides a means of identifying different callout points. When PCRE
2918    reaches such a point in the regex, if pcre_callout has been set, the external
2919    function is called. It is provided with data in a structure called
2920    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2921    matching continues; if it returns a non-zero value, the match at the current
2922    point fails. However, backtracking will occur if possible. [This was changed
2923    later and other features added - see item 49 below.]
2924    
2925    29. pcretest is upgraded to test the callout functionality. It provides a
2926    callout function that displays information. By default, it shows the start of
2927    the match and the current position in the text. There are some new data escapes
2928    to vary what happens:
2929    
2930        \C+         in addition, show current contents of captured substrings
2931        \C-         do not supply a callout function
2932        \C!n        return 1 when callout number n is reached
2933        \C!n!m      return 1 when callout number n is reached for the mth time
2934    
2935    30. If pcregrep was called with the -l option and just a single file name, it
2936    output "<stdin>" if a match was found, instead of the file name.
2937    
2938    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2939    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2940    pcre_exec(). This saves a malloc/free per call. The default value of
2941    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2942    when configuring.
2943    
2944    32. The default maximum size of a compiled pattern is 64K. There have been a
2945    few cases of people hitting this limit. The code now uses macros to handle the
2946    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2947    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2948    configuring. Tests 2 and 5 work only with 2-byte links because they output
2949    debugging information about compiled patterns.
2950    
2951    33. Internal code re-arrangements:
2952    
2953    (a) Moved the debugging function for printing out a compiled regex into
2954        its own source file (printint.c) and used #include to pull it into
2955        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2956        separate copies.
2957    
2958    (b) Defined the list of op-code names for debugging as a macro in
2959        internal.h so that it is next to the definition of the opcodes.
2960    
2961    (c) Defined a table of op-code lengths for simpler skipping along compiled
2962        code. This is again a macro in internal.h so that it is next to the
2963        definition of the opcodes.
2964    
2965    34. Added support for recursive calls to individual subpatterns, along the
2966    lines of Robin Houston's patch (but implemented somewhat differently).
2967    
2968    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2969    allow it to read and process whole directories in Win32. This code was
2970    contributed by Lionel Fourquaux; it has not been tested by me.
2971    
2972    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2973    used to name a group. Names consist of alphanumerics and underscores, and must
2974    be unique. Back references use the syntax (?P=name) and recursive calls use
2975    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2976    numbers. The function pcre_fullinfo() can be used after compilation to extract
2977    a name/number map. There are three relevant calls:
2978    
2979      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2980      PCRE_INFO_NAMECOUNT            yields the number of entries
2981      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2982    
2983    The map is a vector of fixed-size entries. The size of each entry depends on
2984    the length of the longest name used. The first two bytes of each entry are the
2985    group number, most significant byte first. There follows the corresponding
2986    name, zero terminated. The names are in alphabetical order.
2987    
2988    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2989    case instead of 255. Making it the same both with and without UTF-8 support
2990    means that the same test output works with both.
2991    
2992    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2993    calling malloc() with a zero argument.
2994    
2995    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2996    optimization. I've improved things by keeping a bitmap of backreferences with
2997    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2998    fact referenced, the optimization can be applied. It is unlikely that a
2999    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
3000    the match to follow \n) will appear inside brackets with a number greater than
3001    31, but if it does, any back reference > 31 suppresses the optimization.
3002    
3003    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
3004    of disabling numbered capturing parentheses. Any opening parenthesis that is
3005    not followed by ? behaves as if it were followed by ?: but named parentheses
3006    can still be used for capturing (and they will acquire numbers in the usual
3007    way).
3008    
3009    41. Redesigned the return codes from the match() function into yes/no/error so
3010    that errors can be passed back from deep inside the nested calls. A malloc
3011    failure while inside a recursive subpattern call now causes the
3012    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
3013    
3014    42. It is now possible to set a limit on the number of times the match()
3015    function is called in a call to pcre_exec(). This facility makes it possible to
3016    limit the amount of recursion and backtracking, though not in a directly
3017    obvious way, because the match() function is used in a number of different
3018    circumstances. The count starts from zero for each position in the subject
3019    string (for non-anchored patterns). The default limit is, for compatibility, a
3020    large number, namely 10 000 000. You can change this in two ways:
3021    
3022    (a) When configuring PCRE before making, you can use --with-match-limit=n
3023        to set a default value for the compiled library.
3024    
3025    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
3026        a different value is set. See 45 below.
3027    
3028    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
3029    
3030    43. Added a new function pcre_config(int, void *) to enable run-time extraction
3031    of things that can be changed at compile time. The first argument specifies
3032    what is wanted and the second points to where the information is to be placed.
3033    The current list of available information is:
3034    
3035      PCRE_CONFIG_UTF8
3036    
3037    The output is an integer that is set to one if UTF-8 support is available;
3038    otherwise it is set to zero.
3039    
3040      PCRE_CONFIG_NEWLINE
3041    
3042    The output is an integer that it set to the value of the code that is used for
3043    newline. It is either LF (10) or CR (13).
3044    
3045      PCRE_CONFIG_LINK_SIZE
3046    
3047    The output is an integer that contains the number of bytes used for internal
3048    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
3049    
3050      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
3051    
3052    The output is an integer that contains the threshold above which the POSIX
3053    interface uses malloc() for output vectors. See item 31 above.
3054    
3055      PCRE_CONFIG_MATCH_LIMIT
3056    
3057    The output is an unsigned integer that contains the default limit of the number
3058    of match() calls in a pcre_exec() execution. See 42 above.
3059    
3060    44. pcretest has been upgraded by the addition of the -C option. This causes it
3061    to extract all the available output from the new pcre_config() function, and to
3062    output it. The program then exits immediately.
3063    
3064    45. A need has arisen to pass over additional data with calls to pcre_exec() in
3065    order to support additional features. One way would have been to define
3066    pcre_exec2() (for example) with extra arguments, but this would not have been
3067    extensible, and would also have required all calls to the original function to
3068    be mapped to the new one. Instead, I have chosen to extend the mechanism that
3069    is used for passing in "extra" data from pcre_study().
3070    
3071    The pcre_extra structure is now exposed and defined in pcre.h. It currently
3072    contains the following fields:
3073    
3074      flags         a bitmap indicating which of the following fields are set
3075      study_data    opaque data from pcre_study()
3076      match_limit   a way of specifying a limit on match() calls for a specific
3077                      call to pcre_exec()
3078      callout_data  data for callouts (see 49 below)
3079    
3080    The flag bits are also defined in pcre.h, and are
3081    
3082      PCRE_EXTRA_STUDY_DATA
3083      PCRE_EXTRA_MATCH_LIMIT
3084      PCRE_EXTRA_CALLOUT_DATA
3085    
3086    The pcre_study() function now returns one of these new pcre_extra blocks, with
3087    the actual study data pointed to by the study_data field, and the
3088    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
3089    before. That is, this change is entirely upwards-compatible and requires no
3090    change to existing code.
3091    
3092    If you want to pass in additional data to pcre_exec(), you can either place it
3093    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3094    block.
3095    
3096    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3097    data string contains the escape sequence \M, pcretest calls pcre_exec() several
3098    times with different match limits, until it finds the minimum value needed for
3099    pcre_exec() to complete. The value is then output. This can be instructive; for
3100    most simple matches the number is quite small, but for pathological cases it
3101    gets very large very quickly.
3102    
3103    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3104    returns the size of the data block pointed to by the study_data field in a
3105    pcre_extra block, that is, the value that was passed as the argument to
3106    pcre_malloc() when PCRE was getting memory in which to place the information
3107    created by pcre_study(). The fourth argument should point to a size_t variable.
3108    pcretest has been extended so that this information is shown after a successful
3109    pcre_study() call when information about the compiled regex is being displayed.
3110    
3111    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3112    because what follows is always an absolute path. (Later: it turns out that this
3113    is more than cosmetic for MinGW, because it doesn't like empty path
3114    components.)
3115    
3116    49. Some changes have been made to the callout feature (see 28 above):
3117    
3118    (i)  A callout function now has three choices for what it returns:
3119    
3120           0  =>  success, carry on matching
3121         > 0  =>  failure at this point, but backtrack if possible
3122         < 0  =>  serious error, return this value from pcre_exec()
3123    
3124         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3125         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3126         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3127         use by callout functions. It will never be used by PCRE itself.
3128    
3129    (ii) The pcre_extra structure (see 45 above) has a void * field called
3130         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3131         pcre_callout_block structure has a field of the same name. The contents of
3132         the field passed in the pcre_extra structure are passed to the callout
3133         function in the corresponding field in the callout block. This makes it
3134         easier to use the same callout-containing regex from multiple threads. For
3135         testing, the pcretest program has a new data escape
3136    
3137           \C*n        pass the number n (may be negative) as callout_data
3138    
3139         If the callout function in pcretest receives a non-zero value as
3140         callout_data, it returns that value.
3141    
3142    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3143    there were some redundant $(CFLAGS) in commands that are now specified as
3144    $(LINK), which already includes $(CFLAGS).
3145    
3146    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3147    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3148    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3149    one-byte characters throughout. Note that case-insensitive matching applies
3150    only to characters whose values are less than 256. PCRE doesn't support the
3151    notion of cases for higher-valued characters.
3152    
3153    (i)   A character class whose characters are all within 0-255 is handled as
3154          a bit map, and the map is inverted for negative classes. Previously, a
3155          character > 255 always failed to match such a class; however it should
3156          match if the class was a negative one (e.g. [^ab]). This has been fixed.
3157    
3158    (ii)  A negated character class with a single character < 255 is coded as
3159          "not this character" (OP_NOT). This wasn't working properly when the test
3160          character was multibyte, either singly or repeated.
3161    
3162    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3163          mode, for example: \x{100}{2,3}.
3164    
3165    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3166          singly or repeated) now correctly test multibyte characters. However,
3167          PCRE doesn't recognize any characters with values greater than 255 as
3168          digits, spaces, or word characters. Such characters always match \D, \S,
3169          and \W, and never match \d, \s, or \w.
3170    
3171    (v)   Classes may now contain characters and character ranges with values
3172          greater than 255. For example: [ab\x{100}-\x{400}].
3173    
3174    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
3175          PCRE in UTF-8 mode.
3176    
3177    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3178    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3179    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3180    value.)
3181    
3182    53. The single man page has become too large. I have therefore split it up into
3183    a number of separate man pages. These also give rise to individual HTML pages;
3184    these are now put in a separate directory, and there is an index.html page that
3185    lists them all. Some hyperlinking between the pages has been installed.
3186    
3187    54. Added convenience functions for handling named capturing parentheses.
3188    
3189    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3190    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3191    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3192    are faulted.
3193    
3194    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3195    calling configure. These values are used when compiling the dftables.c program
3196    which is run to generate the source of the default character tables. They
3197    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3198    you will need to set these values.
3199    
3200    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3201    
3202    
3203    Version 3.9 02-Jan-02
3204    ---------------------
3205    
3206    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3207    
3208    2. If --disable-static was given, the building process failed when trying to
3209    build pcretest and pcregrep. (For some reason it was using libtool to compile
3210    them, which is not right, as they aren't part of the library.)
3211    
3212    
3213    Version 3.8 18-Dec-01
3214    ---------------------
3215    
3216    1. The experimental UTF-8 code was completely screwed up. It was packing the
3217    bytes in the wrong order. How dumb can you get?
3218    
3219    
3220    Version 3.7 29-Oct-01
3221    ---------------------
3222    
3223    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3224    This caused pcretest, when used on the test data, to segfault. Unfortunately,
3225    this didn't happen under Solaris 8, where I normally test things.
3226    
3227    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3228    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3229    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3230    this fix an hour or so after the initial 3.7 release.)
3231    
3232    
3233  Version 3.6 23-Oct-01  Version 3.6 23-Oct-01
3234  ---------------------  ---------------------
3235    

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