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

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