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revision 71 by nigel, Sat Feb 24 21:40:24 2007 UTC revision 567 by ph10, Sat Nov 6 17:10:00 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.11 10-Oct-2010
5    ------------------------
6    
7    1.  (*THEN) was not working properly if there were untried alternatives prior
8        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9        backtracked to try for "b" instead of moving to the next alternative branch
10        at the same level (in this case, to look for "c"). The Perl documentation
11        is clear that when (*THEN) is backtracked onto, it goes to the "next
12        alternative in the innermost enclosing group".
13    
14    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
16        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18        (*THEN).
19    
20    3.  If \s appeared in a character class, it removed the VT character from
21        the class, even if it had been included by some previous item, for example
22        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
23        of \s, but is part of the POSIX "space" class.)
24    
25    4.  A partial match never returns an empty string (because you can always
26        match an empty string at the end of the subject); however the checking for
27        an empty string was starting at the "start of match" point. This has been
28        changed to the "earliest inspected character" point, because the returned
29        data for a partial match starts at this character. This means that, for
30        example, /(?<=abc)def/ gives a partial match for the subject "abc"
31        (previously it gave "no match").
32    
33    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
34        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
35        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
36        has an implication that the given string is incomplete (because a partial
37        match is preferred over a full match). For this reason, these items now
38        give a partial match in this situation. [Aside: previously, the one case
39        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
40        match rather than a full match, which was wrong by the old rules, but is
41        now correct.]
42    
43    6.  There was a bug in the handling of #-introduced comments, recognized when
44        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
45        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
46        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
47        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
48        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
49        places in pcre_compile().
50    
51    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
52        comments when looking ahead for named forward references to subpatterns,
53        the only newline sequence it recognized was NL. It now handles newlines
54        according to the set newline convention.
55    
56    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
57        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
58        cater for a lack of strerror(). These oversights have been fixed.
59    
60    9.  Added --match-limit and --recursion-limit to pcregrep.
61    
62    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
63    
64    11. When the -o option was used, pcregrep was setting a return code of 1, even
65        when matches were found, and --line-buffered was not being honoured.
66    
67    12. Added an optional parentheses number to the -o and --only-matching options
68        of pcregrep.
69    
70    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
71        can match an empty string. The code to do it in pcretest and pcredemo
72        needed fixing:
73    
74        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
75            only one byte after an empty string match just before CRLF (this case
76            just got forgotten; "any" and "anycrlf" were OK).
77    
78        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
79            mode when an empty string match preceded an ASCII character followed by
80            a non-ASCII character. (The code for advancing by one character rather
81            than one byte was nonsense.)
82    
83        (c) The pcredemo.c sample program did not have any code at all to handle
84            the cases when CRLF is a valid newline sequence.
85    
86    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
87        as a starting offset was within the subject string. There is now a new
88        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
89        negative or greater than the length of the string. In order to test this,
90        pcretest is extended to allow the setting of negative starting offsets.
91    
92    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
93        starting offset points to the beginning of a UTF-8 character was
94        unnecessarily clumsy. I tidied it up.
95    
96    
97    Version 8.10 25-Jun-2010
98    ------------------------
99    
100    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
101        THEN.
102    
103    2.  (*ACCEPT) was not working when inside an atomic group.
104    
105    3.  Inside a character class, \B is treated as a literal by default, but
106        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
107        causes the error). The code is unchanged, but I tidied the documentation.
108    
109    4.  Inside a character class, PCRE always treated \R and \X as literals,
110        whereas Perl faults them if its -w option is set. I have changed PCRE so
111        that it faults them when PCRE_EXTRA is set.
112    
113    5.  Added support for \N, which always matches any character other than
114        newline. (It is the same as "." when PCRE_DOTALL is not set.)
115    
116    6.  When compiling pcregrep with newer versions of gcc which may have
117        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
118        declared with attribute warn_unused_result" were given. Just casting the
119        result to (void) does not stop the warnings; a more elaborate fudge is
120        needed. I've used a macro to implement this.
121    
122    7.  Minor change to pcretest.c to avoid a compiler warning.
123    
124    8.  Added four artifical Unicode properties to help with an option to make
125        \s etc use properties (see next item). The new properties are: Xan
126        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
127    
128    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
129        use Unicode properties. (*UCP) at the start of a pattern can be used to set
130        this option. Modified pcretest to add /W to test this facility. Added
131        REG_UCP to make it available via the POSIX interface.
132    
133    10. Added --line-buffered to pcregrep.
134    
135    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
136        studied, and the match started with a letter with a code point greater than
137        127 whose first byte was different to the first byte of the other case of
138        the letter, the other case of this starting letter was not recognized
139        (#976).
140    
141    12. If a pattern that was studied started with a repeated Unicode property
142        test, for example, \p{Nd}+, there was the theoretical possibility of
143        setting up an incorrect bitmap of starting bytes, but fortunately it could
144        not have actually happened in practice until change 8 above was made (it
145        added property types that matched character-matching opcodes).
146    
147    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
148        possible starting bytes for non-anchored patterns.
149    
150    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
151        \R, and also a number of cases that involve Unicode properties, both
152        explicit and implicit when PCRE_UCP is set.
153    
154    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
155        input, it could crash or give wrong results if characters with values
156        greater than 0xc0 were present in the subject string. (Detail: it assumed
157        UTF-8 input when processing these items.)
158    
159    16. Added a lot of (int) casts to avoid compiler warnings in systems where
160        size_t is 64-bit (#991).
161    
162    17. Added a check for running out of memory when PCRE is compiled with
163        --disable-stack-for-recursion (#990).
164    
165    18. If the last data line in a file for pcretest does not have a newline on
166        the end, a newline was missing in the output.
167    
168    19. The default pcre_chartables.c file recognizes only ASCII characters (values
169        less than 128) in its various bitmaps. However, there is a facility for
170        generating tables according to the current locale when PCRE is compiled. It
171        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
172        characters, are recognized by isspace() and therefore were getting set in
173        these tables, and indeed these tables seem to approximate to ISO 8859. This
174        caused a problem in UTF-8 mode when pcre_study() was used to create a list
175        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
176        which of course cannot start UTF-8 characters. I have changed the code so
177        that only real ASCII characters (less than 128) and the correct starting
178        bytes for UTF-8 encodings are set for characters greater than 127 when in
179        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
180        altogether.)
181    
182    20. Added the /T option to pcretest so as to be able to run tests with non-
183        standard character tables, thus making it possible to include the tests
184        used for 19 above in the standard set of tests.
185    
186    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
187        reference to a subpattern the other side of a comment that contains an
188        opening parenthesis caused either an internal compiling error, or a
189        reference to the wrong subpattern.
190    
191    
192    Version 8.02 19-Mar-2010
193    ------------------------
194    
195    1.  The Unicode data tables have been updated to Unicode 5.2.0.
196    
197    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
198        configured.
199    
200    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
201        original author of that file, following a query about its status.
202    
203    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
204        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
205    
206    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
207        quantifier applied to a forward-referencing subroutine call, could compile
208        incorrect code or give the error "internal error: previously-checked
209        referenced subpattern not found".
210    
211    6.  Both MS Visual Studio and Symbian OS have problems with initializing
212        variables to point to external functions. For these systems, therefore,
213        pcre_malloc etc. are now initialized to local functions that call the
214        relevant global functions.
215    
216    7.  There were two entries missing in the vectors called coptable and poptable
217        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
218        I've fixed the data, and added a kludgy way of testing at compile time that
219        the lengths are correct (equal to the number of opcodes).
220    
221    8.  Following on from 7, I added a similar kludge to check the length of the
222        eint vector in pcreposix.c.
223    
224    9.  Error texts for pcre_compile() are held as one long string to avoid too
225        much relocation at load time. To find a text, the string is searched,
226        counting zeros. There was no check for running off the end of the string,
227        which could happen if a new error number was added without updating the
228        string.
229    
230    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
231    
232    11. \K was not working if it appeared in an atomic group or in a group that
233        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
234        \K is "not well defined" if used in an assertion. PCRE now accepts it if
235        the assertion is positive, but not if it is negative.
236    
237    12. Change 11 fortuitously reduced the size of the stack frame used in the
238        "match()" function of pcre_exec.c by one pointer. Forthcoming
239        implementation of support for (*MARK) will need an extra pointer on the
240        stack; I have reserved it now, so that the stack frame size does not
241        decrease.
242    
243    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
244        item in branch that calls a recursion is a subroutine call - as in the
245        second branch in the above example - was incorrectly given the compile-
246        time error "recursive call could loop indefinitely" because pcre_compile()
247        was not correctly checking the subroutine for matching a non-empty string.
248    
249    14. The checks for overrunning compiling workspace could trigger after an
250        overrun had occurred. This is a "should never occur" error, but it can be
251        triggered by pathological patterns such as hundreds of nested parentheses.
252        The checks now trigger 100 bytes before the end of the workspace.
253    
254    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
255    
256    
257    Version 8.01 19-Jan-2010
258    ------------------------
259    
260    1.  If a pattern contained a conditional subpattern with only one branch (in
261        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
262        computed the wrong minimum data length (which is of course zero for such
263        subpatterns). This could cause incorrect "no match" results.
264    
265    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
266        the pattern is reset in the first branch, pcre_compile() failed with
267        "internal error: code overflow at offset...". This happened only when
268        the reset was to the original external option setting. (An optimization
269        abstracts leading options settings into an external setting, which was the
270        cause of this.)
271    
272    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
273        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
274        assertion pattern did not match (meaning that the assertion was true), it
275        was incorrectly treated as false if the SKIP had been reached during the
276        matching. This also applied to assertions used as conditions.
277    
278    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
279        assertion subpattern, including such a pattern used as a condition,
280        unpredictable results occurred, instead of the error return
281        PCRE_ERROR_DFA_UITEM.
282    
283    5.  The C++ GlobalReplace function was not working like Perl for the special
284        situation when an empty string is matched. It now does the fancy magic
285        stuff that is necessary.
286    
287    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
288        removed. (These were left over from very, very early versions of PCRE.)
289    
290    7.  Some cosmetic changes to the code to make life easier when compiling it
291        as part of something else:
292    
293        (a) Change DEBUG to PCRE_DEBUG.
294    
295        (b) In pcre_compile(), rename the member of the "branch_chain" structure
296            called "current" as "current_branch", to prevent a collision with the
297            Linux macro when compiled as a kernel module.
298    
299        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
300            prevent a collision with the Linux macro when compiled as a kernel
301            module.
302    
303    8.  In pcre_compile() there are some checks for integer overflows that used to
304        cast potentially large values to (double). This has been changed to that
305        when building, a check for int64_t is made, and if it is found, it is used
306        instead, thus avoiding the use of floating point arithmetic. (There is no
307        other use of FP in PCRE.) If int64_t is not found, the fallback is to
308        double.
309    
310    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
311        2005 (difference between two addresses compared to an unsigned value).
312    
313    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
314        custom one, because of the following reported problem in Windows:
315    
316          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
317              under Win32.
318          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
319              therefore missing the function definition.
320          - The compiler thus generates a "C" signature for the test function.
321          - The linker fails to find the "C" function.
322          - PCRE fails to configure if asked to do so against libbz2.
323    
324    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
325        messages were output:
326    
327          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
328          rerunning libtoolize, to keep the correct libtool macros in-tree.
329          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
330    
331        I have done both of these things.
332    
333    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
334        most of the time, it *can* run out if it is given a pattern that contains a
335        runaway infinite recursion. I updated the discussion in the pcrestack man
336        page.
337    
338    13. Now that we have gone to the x.xx style of version numbers, the minor
339        version may start with zero. Using 08 or 09 is a bad idea because users
340        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
341        interpreted as invalid octal numbers. I've updated the previous comment in
342        configure.ac, and also added a check that gives an error if 08 or 09 are
343        used.
344    
345    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
346        causing partial matching to fail when the end of the subject matched \W
347        in a UTF-8 pattern where \W was quantified with a minimum of 3.
348    
349    15. There were some discrepancies between the declarations in pcre_internal.h
350        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
351        their definitions. The declarations used "const uschar *" and the
352        definitions used USPTR. Even though USPTR is normally defined as "const
353        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
354        reported that: "This difference in casting confuses some C++ compilers, for
355        example, SunCC recognizes above declarations as different functions and
356        generates broken code for hbpcre." I have changed the declarations to use
357        USPTR.
358    
359    16. GNU libtool is named differently on some systems. The autogen.sh script now
360        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
361        (FreeBSD).
362    
363    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
364        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
365        comment: "Figure out how to create a longlong from a string: strtoll and
366        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
367        instance, but it only takes 2 args instead of 3!"
368    
369    18. A subtle bug concerned with back references has been fixed by a change of
370        specification, with a corresponding code fix. A pattern such as
371        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
372        refers, was giving matches when it shouldn't. For example, xa=xaaa would
373        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
374        same bug. Such groups have to be quantified to be useful, or contained
375        inside another quantified group. (If there's no repetition, the reference
376        can never match.) The problem arises because, having left the group and
377        moved on to the rest of the pattern, a later failure that backtracks into
378        the group uses the captured value from the final iteration of the group
379        rather than the correct earlier one. I have fixed this in PCRE by forcing
380        any group that contains a reference to itself to be an atomic group; that
381        is, there cannot be any backtracking into it once it has completed. This is
382        similar to recursive and subroutine calls.
383    
384    
385    Version 8.00 19-Oct-09
386    ----------------------
387    
388    1.  The table for translating pcre_compile() error codes into POSIX error codes
389        was out-of-date, and there was no check on the pcre_compile() error code
390        being within the table. This could lead to an OK return being given in
391        error.
392    
393    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
394        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
395        in a Windows environment.
396    
397    3.  The pcregrep --count option prints the count for each file even when it is
398        zero, as does GNU grep. However, pcregrep was also printing all files when
399        --files-with-matches was added. Now, when both options are given, it prints
400        counts only for those files that have at least one match. (GNU grep just
401        prints the file name in this circumstance, but including the count seems
402        more useful - otherwise, why use --count?) Also ensured that the
403        combination -clh just lists non-zero counts, with no names.
404    
405    4.  The long form of the pcregrep -F option was incorrectly implemented as
406        --fixed_strings instead of --fixed-strings. This is an incompatible change,
407        but it seems right to fix it, and I didn't think it was worth preserving
408        the old behaviour.
409    
410    5.  The command line items --regex=pattern and --regexp=pattern were not
411        recognized by pcregrep, which required --regex pattern or --regexp pattern
412        (with a space rather than an '='). The man page documented the '=' forms,
413        which are compatible with GNU grep; these now work.
414    
415    6.  No libpcreposix.pc file was created for pkg-config; there was just
416        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
417    
418    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
419        when UCP support is not needed, by modifying the Python script that
420        generates it from Unicode data files. This should not matter if the module
421        is correctly used as a library, but I received one complaint about 50K of
422        unwanted data. My guess is that the person linked everything into his
423        program rather than using a library. Anyway, it does no harm.
424    
425    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
426        was a minimum greater than 1 for a wide character in a possessive
427        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
428        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
429        character. Chaos in the form of incorrect output or a compiling loop could
430        result.
431    
432    9.  The restrictions on what a pattern can contain when partial matching is
433        requested for pcre_exec() have been removed. All patterns can now be
434        partially matched by this function. In addition, if there are at least two
435        slots in the offset vector, the offset of the earliest inspected character
436        for the match and the offset of the end of the subject are set in them when
437        PCRE_ERROR_PARTIAL is returned.
438    
439    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
440        synonymous with PCRE_PARTIAL, for backwards compatibility, and
441        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
442        and may be more useful for multi-segment matching.
443    
444    11. Partial matching with pcre_exec() is now more intuitive. A partial match
445        used to be given if ever the end of the subject was reached; now it is
446        given only if matching could not proceed because another character was
447        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
448        string "Z", which now yields "no match" instead of "partial match". In the
449        case of pcre_dfa_exec(), "no match" is given if every matching path for the
450        final character ended with (*FAIL).
451    
452    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
453        if the pattern had a "must contain" character that was already found in the
454        earlier partial match, unless partial matching was again requested. For
455        example, with the pattern /dog.(body)?/, the "must contain" character is
456        "g". If the first part-match was for the string "dog", restarting with
457        "sbody" failed. This bug has been fixed.
458    
459    13. The string returned by pcre_dfa_exec() after a partial match has been
460        changed so that it starts at the first inspected character rather than the
461        first character of the match. This makes a difference only if the pattern
462        starts with a lookbehind assertion or \b or \B (\K is not supported by
463        pcre_dfa_exec()). It's an incompatible change, but it makes the two
464        matching functions compatible, and I think it's the right thing to do.
465    
466    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
467        so that the demonstration program is easily available in environments where
468        PCRE has not been installed from source.
469    
470    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
471        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
472        library.
473    
474    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
475        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
476        is not the first non-POSIX option to be added. Clearly some people find
477        these options useful.
478    
479    17. If a caller to the POSIX matching function regexec() passes a non-zero
480        value for nmatch with a NULL value for pmatch, the value of
481        nmatch is forced to zero.
482    
483    18. RunGrepTest did not have a test for the availability of the -u option of
484        the diff command, as RunTest does. It now checks in the same way as
485        RunTest, and also checks for the -b option.
486    
487    19. If an odd number of negated classes containing just a single character
488        interposed, within parentheses, between a forward reference to a named
489        subpattern and the definition of the subpattern, compilation crashed with
490        an internal error, complaining that it could not find the referenced
491        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
492        [The bug was that it was starting one character too far in when skipping
493        over the character class, thus treating the ] as data rather than
494        terminating the class. This meant it could skip too much.]
495    
496    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
497        /g option in pcretest when the pattern contains \K, which makes it possible
498        to have an empty string match not at the start, even when the pattern is
499        anchored. Updated pcretest and pcredemo to use this option.
500    
501    21. If the maximum number of capturing subpatterns in a recursion was greater
502        than the maximum at the outer level, the higher number was returned, but
503        with unset values at the outer level. The correct (outer level) value is
504        now given.
505    
506    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
507        PCRE did not set those parentheses (unlike Perl). I have now found a way to
508        make it do so. The string so far is captured, making this feature
509        compatible with Perl.
510    
511    23. The tests have been re-organized, adding tests 11 and 12, to make it
512        possible to check the Perl 5.10 features against Perl 5.10.
513    
514    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
515        pattern matches a fixed length string. PCRE did not allow this; now it
516        does. Neither allows recursion.
517    
518    25. I finally figured out how to implement a request to provide the minimum
519        length of subject string that was needed in order to match a given pattern.
520        (It was back references and recursion that I had previously got hung up
521        on.) This code has now been added to pcre_study(); it finds a lower bound
522        to the length of subject needed. It is not necessarily the greatest lower
523        bound, but using it to avoid searching strings that are too short does give
524        some useful speed-ups. The value is available to calling programs via
525        pcre_fullinfo().
526    
527    26. While implementing 25, I discovered to my embarrassment that pcretest had
528        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
529        study optimizations had never been tested with that matching function.
530        Oops. What is worse, even when it was passed study data, there was a bug in
531        pcre_dfa_exec() that meant it never actually used it. Double oops. There
532        were also very few tests of studied patterns with pcre_dfa_exec().
533    
534    27. If (?| is used to create subpatterns with duplicate numbers, they are now
535        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
536        on the other side of the coin, they are no longer allowed to have different
537        names, because these cannot be distinguished in PCRE, and this has caused
538        confusion. (This is a difference from Perl.)
539    
540    28. When duplicate subpattern names are present (necessarily with different
541        numbers, as required by 27 above), and a test is made by name in a
542        conditional pattern, either for a subpattern having been matched, or for
543        recursion in such a pattern, all the associated numbered subpatterns are
544        tested, and the overall condition is true if the condition is true for any
545        one of them. This is the way Perl works, and is also more like the way
546        testing by number works.
547    
548    
549    Version 7.9 11-Apr-09
550    ---------------------
551    
552    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
553        (pcretest), all targets were linked against these libraries. This included
554        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
555        libraries. This caused unwanted dependencies to be created. This problem
556        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
557        pcretest is linked with readline.
558    
559    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
560        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
561        moved outside it again, because FALSE and TRUE are already defined in AIX,
562        but BOOL is not.
563    
564    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
565        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
566    
567    4.  The pcregrep documentation said spaces were inserted as well as colons (or
568        hyphens) following file names and line numbers when outputting matching
569        lines. This is not true; no spaces are inserted. I have also clarified the
570        wording for the --colour (or --color) option.
571    
572    5.  In pcregrep, when --colour was used with -o, the list of matching strings
573        was not coloured; this is different to GNU grep, so I have changed it to be
574        the same.
575    
576    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
577        each matching line was coloured. Now it goes on to look for further matches
578        of any of the test patterns, which is the same behaviour as GNU grep.
579    
580    7.  A pattern that could match an empty string could cause pcregrep to loop; it
581        doesn't make sense to accept an empty string match in pcregrep, so I have
582        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
583        seems to be how GNU grep behaves.
584    
585    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
586        start or after a newline", because the conditional assertion was not being
587        correctly handled. The rule now is that both the assertion and what follows
588        in the first alternative must satisfy the test.
589    
590    9.  If auto-callout was enabled in a pattern with a conditional group whose
591        condition was an assertion, PCRE could crash during matching, both with
592        pcre_exec() and pcre_dfa_exec().
593    
594    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
595        used for matching.
596    
597    11. Unicode property support in character classes was not working for
598        characters (bytes) greater than 127 when not in UTF-8 mode.
599    
600    12. Added the -M command line option to pcretest.
601    
602    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
603    
604    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
605    
606    16. Added comments and documentation about mis-use of no_arg in the C++
607        wrapper.
608    
609    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
610        from Martin Jerabek that uses macro names for all relevant character and
611        string constants.
612    
613    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
614        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
615        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
616        these, but not everybody uses configure.
617    
618    19. A conditional group that had only one branch was not being correctly
619        recognized as an item that could match an empty string. This meant that an
620        enclosing group might also not be so recognized, causing infinite looping
621        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
622        with the subject "ab", where knowledge that the repeated group can match
623        nothing is needed in order to break the loop.
624    
625    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
626        exec(), but without supplying a callout function, matching went wrong.
627    
628    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
629        leak if the size of the offset vector was greater than 30. When the vector
630        is smaller, the saved offsets during recursion go onto a local stack
631        vector, but for larger vectors malloc() is used. It was failing to free
632        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
633        error, in fact).
634    
635    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
636        heapframe that is used only when UTF-8 support is enabled. This caused no
637        problem, but was untidy.
638    
639    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
640        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
641        included within another project.
642    
643    24. Steven Van Ingelgem's patches to add more options to the CMake support,
644        slightly modified by me:
645    
646          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
647              not building pcregrep.
648    
649          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
650              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
651    
652    25. Forward references, both numeric and by name, in patterns that made use of
653        duplicate group numbers, could behave incorrectly or give incorrect errors,
654        because when scanning forward to find the reference group, PCRE was not
655        taking into account the duplicate group numbers. A pattern such as
656        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
657    
658    26. Changed a few more instances of "const unsigned char *" to USPTR, making
659        the feature of a custom pointer more persuasive (as requested by a user).
660    
661    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
662        pcretest.c, inside #ifndefs, because it seems they are sometimes already
663        pre-defined.
664    
665    28. Added support for (*UTF8) at the start of a pattern.
666    
667    29. Arrange for flags added by the "release type" setting in CMake to be shown
668        in the configuration summary.
669    
670    
671    Version 7.8 05-Sep-08
672    ---------------------
673    
674    1.  Replaced UCP searching code with optimized version as implemented for Ad
675        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
676        stage table and inline lookup instead of a function, giving speed ups of 2
677        to 5 times on some simple patterns that I tested. Permission was given to
678        distribute the MultiStage2.py script that generates the tables (it's not in
679        the tarball, but is in the Subversion repository).
680    
681    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
682        scripts.
683    
684    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
685        a group with a zero qualifier. The result of the study could be incorrect,
686        or the function might crash, depending on the pattern.
687    
688    4.  Caseless matching was not working for non-ASCII characters in back
689        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
690        It now works when Unicode Property Support is available.
691    
692    5.  In pcretest, an escape such as \x{de} in the data was always generating
693        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
694        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
695        truncation.
696    
697    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
698    
699    7.  Added two (int) casts to pcregrep when printing the difference of two
700        pointers, in case they are 64-bit values.
701    
702    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
703        test 2 if it fails.
704    
705    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
706        and a #define of that name to empty if it is not externally set. This is to
707        allow users of MSVC to set it if necessary.
708    
709    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
710        the convenience functions in the pcre_get.c source file.
711    
712    11. An option change at the start of a pattern that had top-level alternatives
713        could cause overwriting and/or a crash. This command provoked a crash in
714        some environments:
715    
716          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
717    
718        This potential security problem was recorded as CVE-2008-2371.
719    
720    12. For a pattern where the match had to start at the beginning or immediately
721        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
722        pcre_dfa_exec() could read past the end of the passed subject if there was
723        no match. To help with detecting such bugs (e.g. with valgrind), I modified
724        pcretest so that it places the subject at the end of its malloc-ed buffer.
725    
726    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
727        exec() might read past the end of the data buffer in UTF-8 mode.
728    
729    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
730        the data contained the byte 0x85 as part of a UTF-8 character within its
731        first line. This applied both to normal and DFA matching.
732    
733    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
734        /^[^d]*?$/8 failed to match "abc".
735    
736    16. Added a missing copyright notice to pcrecpp_internal.h.
737    
738    17. Make it more clear in the documentation that values returned from
739        pcre_exec() in ovector are byte offsets, not character counts.
740    
741    18. Tidied a few places to stop certain compilers from issuing warnings.
742    
743    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
744        supplied by Stefan Weber. I made a further small update for 7.8 because
745        there is a change of source arrangements: the pcre_searchfuncs.c module is
746        replaced by pcre_ucd.c.
747    
748    
749    Version 7.7 07-May-08
750    ---------------------
751    
752    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
753        a string to a long long, pretend we don't even have a long long." This is
754        done by checking for the strtoq, strtoll, and _strtoi64 functions.
755    
756    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
757        pre-7.6 versions, which defined a global no_arg variable instead of putting
758        it in the RE class. (See also #8 below.)
759    
760    3.  Remove a line of dead code, identified by coverity and reported by Nuno
761        Lopes.
762    
763    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
764    
765        (1) The include/exclude patterns were being applied to the whole pathnames
766            of files, instead of just to the final components.
767    
768        (2) If there was more than one level of directory, the subdirectories were
769            skipped unless they satisfied the include/exclude conditions. This is
770            inconsistent with GNU grep (and could even be seen as contrary to the
771            pcregrep specification - which I improved to make it absolutely clear).
772            The action now is always to scan all levels of directory, and just
773            apply the include/exclude patterns to regular files.
774    
775    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
776        --exclude_dir in the tests to avoid scanning .svn directories.
777    
778    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
779        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
780        doesn't support NULs in patterns.
781    
782    7.  Added some missing "const"s to declarations of static tables in
783        pcre_compile.c and pcre_dfa_exec.c.
784    
785    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
786        caused by fix #2  above. (Subsequently also a second patch to fix the
787        first patch. And a third patch - this was a messy problem.)
788    
789    9.  Applied Craig's patch to remove the use of push_back().
790    
791    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
792        matching function regexec().
793    
794    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
795        which, however, unlike Perl's \g{...}, are subroutine calls, not back
796        references. PCRE supports relative numbers with this syntax (I don't think
797        Oniguruma does).
798    
799    12. Previously, a group with a zero repeat such as (...){0} was completely
800        omitted from the compiled regex. However, this means that if the group
801        was called as a subroutine from elsewhere in the pattern, things went wrong
802        (an internal error was given). Such groups are now left in the compiled
803        pattern, with a new opcode that causes them to be skipped at execution
804        time.
805    
806    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
807        to the way PCRE behaves:
808    
809        (a) A lone ] character is dis-allowed (Perl treats it as data).
810    
811        (b) A back reference to an unmatched subpattern matches an empty string
812            (Perl fails the current match path).
813    
814        (c) A data ] in a character class must be notated as \] because if the
815            first data character in a class is ], it defines an empty class. (In
816            Perl it is not possible to have an empty class.) The empty class []
817            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
818            The negative empty class [^] matches any one character, independently
819            of the DOTALL setting.
820    
821    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
822        non-existent subpattern following a character class starting with ']' and
823        containing () gave an internal compiling error instead of "reference to
824        non-existent subpattern". Fortunately, when the pattern did exist, the
825        compiled code was correct. (When scanning forwards to check for the
826        existencd of the subpattern, it was treating the data ']' as terminating
827        the class, so got the count wrong. When actually compiling, the reference
828        was subsequently set up correctly.)
829    
830    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
831        it was being rejected as not supported by pcre_dfa_exec(), even though
832        other assertions are supported. I have made pcre_dfa_exec() support
833        (*FAIL).
834    
835    16. The implementation of 13c above involved the invention of a new opcode,
836        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
837        cannot be changed at match time, I realized I could make a small
838        improvement to matching performance by compiling OP_ALLANY instead of
839        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
840        on the OP_ANY path.
841    
842    17. Compiling pcretest on Windows with readline support failed without the
843        following two fixes: (1) Make the unistd.h include conditional on
844        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
845    
846    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
847        ncurses library to be included for pcretest when ReadLine support is
848        requested, but also to allow for it to be overridden. This patch came from
849        Daniel Bergström.
850    
851    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
852        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
853        any errors with the current Unicode tables. Thanks to Peter Kankowski for
854        spotting this.
855    
856    
857    Version 7.6 28-Jan-08
858    ---------------------
859    
860    1.  A character class containing a very large number of characters with
861        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
862        overflow.
863    
864    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
865        HAVE_LONG_LONG is not defined.
866    
867    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
868        bring them up to date and include new features. This patch includes:
869    
870        - Fixed PH's badly added libz and libbz2 support.
871        - Fixed a problem with static linking.
872        - Added pcredemo. [But later removed - see 7 below.]
873        - Fixed dftables problem and added an option.
874        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
875            HAVE_LONG_LONG.
876        - Added readline support for pcretest.
877        - Added an listing of the option settings after cmake has run.
878    
879    4.  A user submitted a patch to Makefile that makes it easy to create
880        "pcre.dll" under mingw when using Configure/Make. I added stuff to
881        Makefile.am that cause it to include this special target, without
882        affecting anything else. Note that the same mingw target plus all
883        the other distribution libraries and programs are now supported
884        when configuring with CMake (see 6 below) instead of with
885        Configure/Make.
886    
887    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
888        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
889        exported in the Windows port". It has not yet been confirmed that the patch
890        solves the problem, but it does no harm.
891    
892    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
893        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
894        with CMake, and also correct the comment about stack recursion.
895    
896    7.  Remove the automatic building of pcredemo from the ./configure system and
897        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
898        of a program that users should build themselves after PCRE is installed, so
899        building it automatically is not really right. What is more, it gave
900        trouble in some build environments.
901    
902    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
903    
904    
905    Version 7.5 10-Jan-08
906    ---------------------
907    
908    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
909        values in parens when parsing an RE using the C++ wrapper."
910    
911    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
912        Characters greater than 255 were excluded from the class instead of being
913        included.
914    
915    3.  The same bug as (2) above applied to negated POSIX classes such as
916        [:^space:].
917    
918    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
919        defined or documented. It seems to have been a typo for PCRE_STATIC, so
920        I have changed it.
921    
922    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
923        first named subpattern) and a construct such as (?&a) would reference the
924        first named subpattern whose name started with "a" (in other words, the
925        length check was missing). Both these problems are fixed. "Subpattern name
926        expected" is now given for (?&) (a zero-length name), and this patch also
927        makes it give the same error for \k'' (previously it complained that that
928        was a reference to a non-existent subpattern).
929    
930    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
931        this is right because (?- can be followed by option settings as well as by
932        digits. I have, however, made the messages clearer.
933    
934    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
935        than the number used in the conditional) now cause a compile-time error.
936        This is actually not compatible with Perl, which accepts such patterns, but
937        treats the conditional as always being FALSE (as PCRE used to), but it
938        seems to me that giving a diagnostic is better.
939    
940    8.  Change "alphameric" to the more common word "alphanumeric" in comments
941        and messages.
942    
943    9.  Fix two occurrences of "backslash" in comments that should have been
944        "backspace".
945    
946    10. Remove two redundant lines of code that can never be obeyed (their function
947        was moved elsewhere).
948    
949    11. The program that makes PCRE's Unicode character property table had a bug
950        which caused it to generate incorrect table entries for sequences of
951        characters that have the same character type, but are in different scripts.
952        It amalgamated them into a single range, with the script of the first of
953        them. In other words, some characters were in the wrong script. There were
954        thirteen such cases, affecting characters in the following ranges:
955    
956          U+002b0 - U+002c1
957          U+0060c - U+0060d
958          U+0061e - U+00612
959          U+0064b - U+0065e
960          U+0074d - U+0076d
961          U+01800 - U+01805
962          U+01d00 - U+01d77
963          U+01d9b - U+01dbf
964          U+0200b - U+0200f
965          U+030fc - U+030fe
966          U+03260 - U+0327f
967          U+0fb46 - U+0fbb1
968          U+10450 - U+1049d
969    
970    12. The -o option (show only the matching part of a line) for pcregrep was not
971        compatible with GNU grep in that, if there was more than one match in a
972        line, it showed only the first of them. It now behaves in the same way as
973        GNU grep.
974    
975    13. If the -o and -v options were combined for pcregrep, it printed a blank
976        line for every non-matching line. GNU grep prints nothing, and pcregrep now
977        does the same. The return code can be used to tell if there were any
978        non-matching lines.
979    
980    14. Added --file-offsets and --line-offsets to pcregrep.
981    
982    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
983        infinitely looping recursion. The bug was that positive lookaheads were not
984        being skipped when checking for a possible empty match (negative lookaheads
985        and both kinds of lookbehind were skipped).
986    
987    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
988        inclusion of <windows.h> to before rather than after the definition of
989        INVALID_FILE_ATTRIBUTES (patch from David Byron).
990    
991    17. Specifying a possessive quantifier with a specific limit for a Unicode
992        character property caused pcre_compile() to compile bad code, which led at
993        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
994        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
995        caused the error; without that there was no problem.
996    
997    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
998    
999    19. Added --enable-pcretest-libreadline.
1000    
1001    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1002        RE::GlobalReplace(). As a result, the number of replacements returned was
1003        double what it should be. I removed one of the increments, but Craig sent a
1004        later patch that removed the other one (the right fix) and added unit tests
1005        that check the return values (which was not done before).
1006    
1007    21. Several CMake things:
1008    
1009        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1010            the names libpcre and libpcreposix, not just pcre and pcreposix.
1011    
1012        (2) The above change means that pcretest and pcregrep are now correctly
1013            linked with the newly-built libraries, not previously installed ones.
1014    
1015        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1016    
1017    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1018        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1019        UTF-8 newline character). The key issue is that the pattern starts .*;
1020        this means that the match must be either at the beginning, or after a
1021        newline. The bug was in the code for advancing after a failed match and
1022        checking that the new position followed a newline. It was not taking
1023        account of UTF-8 characters correctly.
1024    
1025    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1026        character classes. PCRE was not treating the sequence [:...:] as a
1027        character class unless the ... were all letters. Perl, however, seems to
1028        allow any characters between [: and :], though of course it rejects as
1029        unknown any "names" that contain non-letters, because all the known class
1030        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1031        for example, whereas PCRE did not - it did not recognize a POSIX character
1032        class. This seemed a bit dangerous, so the code has been changed to be
1033        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1034        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1035        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1036        Perl does, and where it didn't before.
1037    
1038    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1039        Windows environments %n is disabled by default.
1040    
1041    
1042    Version 7.4 21-Sep-07
1043    ---------------------
1044    
1045    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1046        means that a class such as [\s] counted as "explicit reference to CR or
1047        LF". That isn't really right - the whole point of the change was to try to
1048        help when there was an actual mention of one of the two characters. So now
1049        the change happens only if \r or \n (or a literal CR or LF) character is
1050        encountered.
1051    
1052    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1053        of both had grown to the point where there were only 3 bits left.
1054        Fortunately, there was spare space in the data structure, and so I have
1055        moved the internal flags into a new 16-bit field to free up more option
1056        bits.
1057    
1058    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1059        but did not set the internal JCHANGED flag - either of these is enough to
1060        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1061        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1062        start sets both bits.
1063    
1064    4.  Added options (at build time, compile time, exec time) to change \R from
1065        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1066    
1067    5.  doc/pcresyntax.html was missing from the distribution.
1068    
1069    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1070        compatibility, even though it is no longer used.
1071    
1072    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1073        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1074        windows.h file is present (where different names are used). [This was
1075        reversed later after testing - see 16 below.]
1076    
1077    8.  Changed all #include <config.h> to #include "config.h". There were also
1078        some further <pcre.h> cases that I changed to "pcre.h".
1079    
1080    9.  When pcregrep was used with the --colour option, it missed the line ending
1081        sequence off the lines that it output.
1082    
1083    10. It was pointed out to me that arrays of string pointers cause lots of
1084        relocations when a shared library is dynamically loaded. A technique of
1085        using a single long string with a table of offsets can drastically reduce
1086        these. I have refactored PCRE in four places to do this. The result is
1087        dramatic:
1088    
1089          Originally:                          290
1090          After changing UCP table:            187
1091          After changing error message table:   43
1092          After changing table of "verbs"       36
1093          After changing table of Posix names   22
1094    
1095        Thanks to the folks working on Gregex for glib for this insight.
1096    
1097    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1098        unicode-properties was also set.
1099    
1100    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1101    
1102    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1103        checked only for CRLF.
1104    
1105    14. Added casts to pcretest.c to avoid compiler warnings.
1106    
1107    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1108    
1109    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1110        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1111        entirely. This removes changes made in 7 above.
1112    
1113    17. The CMake files have been updated, and there is now more information about
1114        building with CMake in the NON-UNIX-USE document.
1115    
1116    
1117    Version 7.3 28-Aug-07
1118    ---------------------
1119    
1120     1. In the rejigging of the build system that eventually resulted in 7.1, the
1121        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1122        brackets there is not right, since it causes compilers to look for an
1123        installed pcre.h, not the version that is in the source that is being
1124        compiled (which of course may be different). I have changed it back to:
1125    
1126          #include "pcre.h"
1127    
1128        I have a vague recollection that the change was concerned with compiling in
1129        different directories, but in the new build system, that is taken care of
1130        by the VPATH setting the Makefile.
1131    
1132     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1133        when the subject happened to end in the byte 0x85 (e.g. if the last
1134        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1135        characters but of course it shouldn't be taken as a newline when it is part
1136        of another character. The bug was that, for an unlimited repeat of . in
1137        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1138        characters when looking for a newline.
1139    
1140     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1141    
1142     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1143        in debug output.
1144    
1145     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1146        long printing in the pcrecpp unittest when running under MinGW.
1147    
1148     6. ESC_K was left out of the EBCDIC table.
1149    
1150     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1151        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1152        limit also applies to "virtual nesting" when a pattern is recursive, and in
1153        this case 1000 isn't so big. I have been able to remove this limit at the
1154        expense of backing off one optimization in certain circumstances. Normally,
1155        when pcre_exec() would call its internal match() function recursively and
1156        immediately return the result unconditionally, it uses a "tail recursion"
1157        feature to save stack. However, when a subpattern that can match an empty
1158        string has an unlimited repetition quantifier, it no longer makes this
1159        optimization. That gives it a stack frame in which to save the data for
1160        checking that an empty string has been matched. Previously this was taken
1161        from the 1000-entry workspace that had been reserved. So now there is no
1162        explicit limit, but more stack is used.
1163    
1164     8. Applied Daniel's patches to solve problems with the import/export magic
1165        syntax that is required for Windows, and which was going wrong for the
1166        pcreposix and pcrecpp parts of the library. These were overlooked when this
1167        problem was solved for the main library.
1168    
1169     9. There were some crude static tests to avoid integer overflow when computing
1170        the size of patterns that contain repeated groups with explicit upper
1171        limits. As the maximum quantifier is 65535, the maximum group length was
1172        set at 30,000 so that the product of these two numbers did not overflow a
1173        32-bit integer. However, it turns out that people want to use groups that
1174        are longer than 30,000 bytes (though not repeat them that many times).
1175        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1176        made it possible to implement the integer overflow checks in a much more
1177        dynamic way, which I have now done. The artificial limitation on group
1178        length has been removed - we now have only the limit on the total length of
1179        the compiled pattern, which depends on the LINK_SIZE setting.
1180    
1181    10. Fixed a bug in the documentation for get/copy named substring when
1182        duplicate names are permitted. If none of the named substrings are set, the
1183        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1184        empty string.
1185    
1186    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1187        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1188        because the ] is interpreted as the first data character and the
1189        terminating ] is not found. PCRE has been made compatible with Perl in this
1190        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1191        cause memory overwriting.
1192    
1193    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1194        string has been matched (to stop an infinite loop). It was not recognizing
1195        a conditional subpattern that could match an empty string if that
1196        subpattern was within another subpattern. For example, it looped when
1197        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1198        condition was not nested. This bug has been fixed.
1199    
1200    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1201        past the start of the subject in the presence of bytes with the top bit
1202        set, for example "\x8aBCD".
1203    
1204    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1205        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1206    
1207    14. Optimized (?!) to (*FAIL).
1208    
1209    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1210        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1211        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1212        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1213        does: it's just the validity check that is more restrictive.
1214    
1215    16. Inserted checks for integer overflows during escape sequence (backslash)
1216        processing, and also fixed erroneous offset values for syntax errors during
1217        backslash processing.
1218    
1219    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1220        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1221    
1222    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1223        caused an overrun.
1224    
1225    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1226        something other than just ASCII characters) inside a group that had an
1227        unlimited repeat caused a loop at compile time (while checking to see
1228        whether the group could match an empty string).
1229    
1230    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1231        [\P{Any}] did so. (Error in the code for printing property names.)
1232    
1233    21. An orphan \E inside a character class could cause a crash.
1234    
1235    22. A repeated capturing bracket such as (A)? could cause a wild memory
1236        reference during compilation.
1237    
1238    23. There are several functions in pcre_compile() that scan along a compiled
1239        expression for various reasons (e.g. to see if it's fixed length for look
1240        behind). There were bugs in these functions when a repeated \p or \P was
1241        present in the pattern. These operators have additional parameters compared
1242        with \d, etc, and these were not being taken into account when moving along
1243        the compiled data. Specifically:
1244    
1245        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1246            length.
1247    
1248        (b) An item such as \pL+ within a repeated group could cause crashes or
1249            loops.
1250    
1251        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1252            "reference to non-existent subpattern" error.
1253    
1254        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1255    
1256    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1257        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1258    
1259    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1260    
1261    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1262        character were causing crashes (broken optimization).
1263    
1264    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1265        \p or \P) caused a compile-time loop.
1266    
1267    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1268        break. For example, the unstudied pattern [\r\n]A does not match the string
1269        "\r\nA" because change 7.0/46 below moves the current point on by two
1270        characters after failing to match at the start. However, the pattern \nA
1271        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1272        the same is true. There doesn't seem any very clean way out of this, but
1273        what I have chosen to do makes the common cases work: PCRE now takes note
1274        of whether there can be an explicit match for \r or \n anywhere in the
1275        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1276        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1277        pattern has explicit CR or LF references.
1278    
1279    29. Added (*CR) etc for changing newline setting at start of pattern.
1280    
1281    
1282    Version 7.2 19-Jun-07
1283    ---------------------
1284    
1285     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1286        which is apparently normally available under Windows.
1287    
1288     2. Re-jig the pcregrep tests with different newline settings in an attempt
1289        to make them independent of the local environment's newline setting.
1290    
1291     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1292    
1293     4. Some of the "internals" tests were previously cut out when the link size
1294        was not 2, because the output contained actual offsets. The recent new
1295        "Z" feature of pcretest means that these can be cut out, making the tests
1296        usable with all link sizes.
1297    
1298     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1299        stack recursion. This gives a massive performance boost under BSD, but just
1300        a small improvement under Linux. However, it saves one field in the frame
1301        in all cases.
1302    
1303     6. Added more features from the forthcoming Perl 5.10:
1304    
1305        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1306            recursion call. It refers to the nth most recently opened parentheses.
1307    
1308        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1309            to be opened parentheses.
1310    
1311        (c) Conditions that refer to capturing parentheses can be specified
1312            relatively, for example, (?(-2)... or (?(+3)...
1313    
1314        (d) \K resets the start of the current match so that everything before
1315            is not part of it.
1316    
1317        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1318    
1319        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1320            reference syntax.
1321    
1322        (g) (?| introduces a group in which the numbering of parentheses in each
1323            alternative starts with the same number.
1324    
1325        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1326    
1327     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1328        PCRE_INFO_JCHANGED.
1329    
1330     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1331        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1332        for detecting groups that can match an empty string.
1333    
1334     9. A pattern with a very large number of alternatives (more than several
1335        hundred) was running out of internal workspace during the pre-compile
1336        phase, where pcre_compile() figures out how much memory will be needed. A
1337        bit of new cunning has reduced the workspace needed for groups with
1338        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1339        workspace instead of running out of the 4096 that are available.
1340    
1341    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1342    
1343    11. Applied patch from Google to remove an optimization that didn't quite work.
1344        The report of the bug said:
1345    
1346          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1347          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1348          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1349    
1350    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1351        it matched the wrong number of bytes.
1352    
1353    
1354    Version 7.1 24-Apr-07
1355    ---------------------
1356    
1357     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1358        that is more "standard", making use of automake and other Autotools. There
1359        is some re-arrangement of the files and adjustment of comments consequent
1360        on this.
1361    
1362     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1363        for recursive directory scanning broke on some systems because the files
1364        are not scanned in any specific order and on different systems the order
1365        was different. A call to "sort" has been inserted into RunGrepTest for the
1366        approprate test as a short-term fix. In the longer term there may be an
1367        alternative.
1368    
1369     3. I had an email from Eric Raymond about problems translating some of PCRE's
1370        man pages to HTML (despite the fact that I distribute HTML pages, some
1371        people do their own conversions for various reasons). The problems
1372        concerned the use of low-level troff macros .br and .in. I have therefore
1373        removed all such uses from the man pages (some were redundant, some could
1374        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1375        HTML has been updated to handle .nf/.fi and to complain if it encounters
1376        .br or .in.
1377    
1378     4. Updated comments in configure.ac that get placed in config.h.in and also
1379        arranged for config.h to be included in the distribution, with the name
1380        config.h.generic, for the benefit of those who have to compile without
1381        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1382    
1383     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1384        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1385        makevp.bat for the current PCRE, using the additional files
1386        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1387    
1388     6. A Windows user reported a minor discrepancy with test 2, which turned out
1389        to be caused by a trailing space on an input line that had got lost in his
1390        copy. The trailing space was an accident, so I've just removed it.
1391    
1392     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1393        that is needed.
1394    
1395     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1396        as "const" (a) because they are and (b) because it helps the PHP
1397        maintainers who have recently made a script to detect big data structures
1398        in the php code that should be moved to the .rodata section. I remembered
1399        to update Builducptable as well, so it won't revert if ucptable.h is ever
1400        re-created.
1401    
1402     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1403        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1404        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1405        support is not required. This saves 1.5-2K of code, which is important in
1406        some applications.
1407    
1408        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1409        so as not to refer to the tables, even though these functions will never be
1410        called when UTF-8 support is disabled. Otherwise there are problems with a
1411        shared library.
1412    
1413    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1414    
1415        (a) It was defining its arguments as char * instead of void *.
1416    
1417        (b) It was assuming that all moves were upwards in memory; this was true
1418            a long time ago when I wrote it, but is no longer the case.
1419    
1420        The emulated memove() is provided for those environments that have neither
1421        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1422        is clearly not the case, as these two bugs were recently reported.
1423    
1424    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1425        and Detrail to create the HTML documentation, the .txt form of the man
1426        pages, and it removes trailing spaces from listed files. It also creates
1427        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1428        case, it wraps all the #defines with #ifndefs. This script should be run
1429        before "make dist".
1430    
1431    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1432        with Unicode property support.
1433    
1434        (a) For a maximizing quantifier, if the two different cases of the
1435            character were of different lengths in their UTF-8 codings (there are
1436            some cases like this - I found 11), and the matching function had to
1437            back up over a mixture of the two cases, it incorrectly assumed they
1438            were both the same length.
1439    
1440        (b) When PCRE was configured to use the heap rather than the stack for
1441            recursion during matching, it was not correctly preserving the data for
1442            the other case of a UTF-8 character when checking ahead for a match
1443            while processing a minimizing repeat. If the check also involved
1444            matching a wide character, but failed, corruption could cause an
1445            erroneous result when trying to check for a repeat of the original
1446            character.
1447    
1448    13. Some tidying changes to the testing mechanism:
1449    
1450        (a) The RunTest script now detects the internal link size and whether there
1451            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1452            values substituted by "configure". (The RunGrepTest script already did
1453            this for UTF-8.) The configure.ac script no longer substitutes the
1454            relevant variables.
1455    
1456        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1457            with length and offset values. This means that the output is different
1458            for different internal link sizes. Test 2 is skipped for link sizes
1459            other than 2 because of this, bypassing the problem. Unfortunately,
1460            there was also a test in test 3 (the locale tests) that used /B and
1461            failed for link sizes other than 2. Rather than cut the whole test out,
1462            I have added a new /Z option to pcretest that replaces the length and
1463            offset values with spaces. This is now used to make test 3 independent
1464            of link size. (Test 2 will be tidied up later.)
1465    
1466    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1467        segmentation fault instead of returning the appropriate error message.
1468    
1469    15. In multiline mode when the newline sequence was set to "any", the pattern
1470        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1471        This doesn't seem right; it now treats the CRLF combination as the line
1472        ending, and so does not match in that case. It's only a pattern such as ^$
1473        that would hit this one: something like ^ABC$ would have failed after \r
1474        and then tried again after \r\n.
1475    
1476    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1477        in an attempt to make files that differ only in their line terminators
1478        compare equal. This works on Linux.
1479    
1480    17. Under certain error circumstances pcregrep might try to free random memory
1481        as it exited. This is now fixed, thanks to valgrind.
1482    
1483    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1484        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1485        was because its rules for how to advance for /g after matching an empty
1486        string at the end of a line did not allow for this case. They now check for
1487        it specially.
1488    
1489    20. pcretest is supposed to handle patterns and data of any length, by
1490        extending its buffers when necessary. It was getting this wrong when the
1491        buffer for a data line had to be extended.
1492    
1493    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1494        CRLF as a newline sequence.
1495    
1496    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1497        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1498        I have nevertheless tidied it up.
1499    
1500    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1501    
1502    24. Added a man page for pcre-config.
1503    
1504    
1505    Version 7.0 19-Dec-06
1506    ---------------------
1507    
1508     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1509        moving to gcc 4.1.1.
1510    
1511     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1512        sys/time.h, which is documented as needed for this function. It doesn't
1513        seem to matter on Linux, but it showed up on some releases of OS X.
1514    
1515     3. It seems that there are systems where bytes whose values are greater than
1516        127 match isprint() in the "C" locale. The "C" locale should be the
1517        default when a C program starts up. In most systems, only ASCII printing
1518        characters match isprint(). This difference caused the output from pcretest
1519        to vary, making some of the tests fail. I have changed pcretest so that:
1520    
1521        (a) When it is outputting text in the compiled version of a pattern, bytes
1522            other than 32-126 are always shown as hex escapes.
1523    
1524        (b) When it is outputting text that is a matched part of a subject string,
1525            it does the same, unless a different locale has been set for the match
1526            (using the /L modifier). In this case, it uses isprint() to decide.
1527    
1528     4. Fixed a major bug that caused incorrect computation of the amount of memory
1529        required for a compiled pattern when options that changed within the
1530        pattern affected the logic of the preliminary scan that determines the
1531        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1532        that the computed length was too small. The symptoms of this bug were
1533        either the PCRE error "internal error: code overflow" from pcre_compile(),
1534        or a glibc crash with a message such as "pcretest: free(): invalid next
1535        size (fast)". Examples of patterns that provoked this bug (shown in
1536        pcretest format) are:
1537    
1538          /(?-x: )/x
1539          /(?x)(?-x: \s*#\s*)/
1540          /((?i)[\x{c0}])/8
1541          /(?i:[\x{c0}])/8
1542    
1543        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1544        is now done differently.
1545    
1546     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1547        wrapper classes; (b) implement a new function in the C++ scanner that is
1548        more efficient than the old way of doing things because it avoids levels of
1549        recursion in the regex matching; (c) add a paragraph to the documentation
1550        for the FullMatch() function.
1551    
1552     6. The escape sequence \n was being treated as whatever was defined as
1553        "newline". Not only was this contrary to the documentation, which states
1554        that \n is character 10 (hex 0A), but it also went horribly wrong when
1555        "newline" was defined as CRLF. This has been fixed.
1556    
1557     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1558        was being set to -1 for the "end of line" case (supposedly a value that no
1559        character can have). Though this value is never used (the check for end of
1560        line is "zero bytes in current character"), it caused compiler complaints.
1561        I've changed it to 0xffffffff.
1562    
1563     8. In pcre_version.c, the version string was being built by a sequence of
1564        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1565        string (as it is for production releases) called a macro with an empty
1566        argument. The C standard says the result of this is undefined. The gcc
1567        compiler treats it as an empty string (which was what was wanted) but it is
1568        reported that Visual C gives an error. The source has been hacked around to
1569        avoid this problem.
1570    
1571     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1572        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1573        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1574        of them did).
1575    
1576    10. Originally, pcretest opened its input and output without "b"; then I was
1577        told that "b" was needed in some environments, so it was added for release
1578        5.0 to both the input and output. (It makes no difference on Unix-like
1579        systems.) Later I was told that it is wrong for the input on Windows. I've
1580        now abstracted the modes into two macros, to make it easier to fiddle with
1581        them, and removed "b" from the input mode under Windows.
1582    
1583    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1584    
1585    12. Added -help and --help to pcretest as an official way of being reminded
1586        of the options.
1587    
1588    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1589        and pcrecpp.cc because they annoy compilers at high warning levels.
1590    
1591    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1592    
1593    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1594        scripts are not C programs :-) and which was not noticed because it works
1595        on Linux.
1596    
1597    16. pcretest is supposed to handle any length of pattern and data line (as one
1598        line or as a continued sequence of lines) by extending its input buffer if
1599        necessary. This feature was broken for very long pattern lines, leading to
1600        a string of junk being passed to pcre_compile() if the pattern was longer
1601        than about 50K.
1602    
1603    17. I have done a major re-factoring of the way pcre_compile() computes the
1604        amount of memory needed for a compiled pattern. Previously, there was code
1605        that made a preliminary scan of the pattern in order to do this. That was
1606        OK when PCRE was new, but as the facilities have expanded, it has become
1607        harder and harder to keep it in step with the real compile phase, and there
1608        have been a number of bugs (see for example, 4 above). I have now found a
1609        cunning way of running the real compile function in a "fake" mode that
1610        enables it to compute how much memory it would need, while actually only
1611        ever using a few hundred bytes of working memory and without too many
1612        tests of the mode. This should make future maintenance and development
1613        easier. A side effect of this work is that the limit of 200 on the nesting
1614        depth of parentheses has been removed (though this was never a serious
1615        limitation, I suspect). However, there is a downside: pcre_compile() now
1616        runs more slowly than before (30% or more, depending on the pattern). I
1617        hope this isn't a big issue. There is no effect on runtime performance.
1618    
1619    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1620        newline (only possible for the last line of a file) and it was a
1621        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1622    
1623    19. Added additional timing features to pcretest. (1) The -tm option now times
1624        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1625        separate command line item, by a number that specifies the number of
1626        repeats to use when timing. The default is 50000; this gives better
1627        precision, but takes uncomfortably long for very large patterns.
1628    
1629    20. Extended pcre_study() to be more clever in cases where a branch of a
1630        subpattern has no definite first character. For example, (a*|b*)[cd] would
1631        previously give no result from pcre_study(). Now it recognizes that the
1632        first character must be a, b, c, or d.
1633    
1634    21. There was an incorrect error "recursive call could loop indefinitely" if
1635        a subpattern (or the entire pattern) that was being tested for matching an
1636        empty string contained only one non-empty item after a nested subpattern.
1637        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1638        incorrectly, because the \d was being skipped in the check.
1639    
1640    22. The pcretest program now has a new pattern option /B and a command line
1641        option -b, which is equivalent to adding /B to every pattern. This causes
1642        it to show the compiled bytecode, without the additional information that
1643        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1644        is the same as /B/I).
1645    
1646    23. A new optimization is now able automatically to treat some sequences such
1647        as a*b as a*+b. More specifically, if something simple (such as a character
1648        or a simple class like \d) has an unlimited quantifier, and is followed by
1649        something that cannot possibly match the quantified thing, the quantifier
1650        is automatically "possessified".
1651    
1652    24. A recursive reference to a subpattern whose number was greater than 39
1653        went wrong under certain circumstances in UTF-8 mode. This bug could also
1654        have affected the operation of pcre_study().
1655    
1656    25. Realized that a little bit of performance could be had by replacing
1657        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1658    
1659    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1660    
1661    27. Possessive quantifiers such as a++ were previously implemented by turning
1662        them into atomic groups such as ($>a+). Now they have their own opcodes,
1663        which improves performance. This includes the automatically created ones
1664        from 23 above.
1665    
1666    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1667        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1668        the first matched character to be a colon. This applied both to named and
1669        numbered groups.
1670    
1671    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1672    
1673    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1674        building PCRE on Windows easier, so I have included it in the distribution.
1675    
1676    31. There is now a check in pcretest against a ridiculously large number being
1677        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1678        loop, the loop is abandoned.
1679    
1680    32. Forward references to subpatterns in conditions such as (?(2)...) where
1681        subpattern 2 is defined later cause pcre_compile() to search forwards in
1682        the pattern for the relevant set of parentheses. This search went wrong
1683        when there were unescaped parentheses in a character class, parentheses
1684        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1685    
1686    33. "Subroutine" calls and backreferences were previously restricted to
1687        referencing subpatterns earlier in the regex. This restriction has now
1688        been removed.
1689    
1690    34. Added a number of extra features that are going to be in Perl 5.10. On the
1691        whole, these are just syntactic alternatives for features that PCRE had
1692        previously implemented using the Python syntax or my own invention. The
1693        other formats are all retained for compatibility.
1694    
1695        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1696            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1697            also .NET compatible.
1698    
1699        (b) A recursion or subroutine call to a named group can now be defined as
1700            (?&name) as well as (?P>name).
1701    
1702        (c) A backreference to a named group can now be defined as \k<name> or
1703            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1704            5.10, are also .NET compatible.
1705    
1706        (d) A conditional reference to a named group can now use the syntax
1707            (?(<name>) or (?('name') as well as (?(name).
1708    
1709        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1710            groups (named and numbered) that are never evaluated inline, but can be
1711            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1712            is always false. There may be only one alternative in such a group.
1713    
1714        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1715            as the simple (?(R). The condition is true only if the most recent
1716            recursion is that of the given number or name. It does not search out
1717            through the entire recursion stack.
1718    
1719        (g) The escape \gN or \g{N} has been added, where N is a positive or
1720            negative number, specifying an absolute or relative reference.
1721    
1722    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1723        some "unreachable code" warnings.
1724    
1725    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1726        things, this adds five new scripts.
1727    
1728    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1729        There were also incompatibilities regarding the handling of \Q..\E inside
1730        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1731        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1732    
1733    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1734        matches an empty string, and forcibly breaks the loop. There were bugs in
1735        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1736        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1737        separate and independent bugs (that affected different cases) have been
1738        fixed.
1739    
1740    39. Refactored the code to abolish the use of different opcodes for small
1741        capturing bracket numbers. This is a tidy that I avoided doing when I
1742        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1743        The new approach is not only tidier, it makes it possible to reduce the
1744        memory needed to fix the previous bug (38).
1745    
1746    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1747        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1748        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1749        mode.
1750    
1751    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1752        report.
1753    
1754    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1755        copy construction and assignment in the C++ wrapper.
1756    
1757    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1758        couple of bugs that could have given wrong results in the "--newline=crlf"
1759        case.
1760    
1761    44. Added a number of casts and did some reorganization of signed/unsigned int
1762        variables following suggestions from Dair Grant. Also renamed the variable
1763        "this" as "item" because it is a C++ keyword.
1764    
1765    45. Arranged for dftables to add
1766    
1767          #include "pcre_internal.h"
1768    
1769        to pcre_chartables.c because without it, gcc 4.x may remove the array
1770        definition from the final binary if PCRE is built into a static library and
1771        dead code stripping is activated.
1772    
1773    46. For an unanchored pattern, if a match attempt fails at the start of a
1774        newline sequence, and the newline setting is CRLF or ANY, and the next two
1775        characters are CRLF, advance by two characters instead of one.
1776    
1777    
1778    Version 6.7 04-Jul-06
1779    ---------------------
1780    
1781     1. In order to handle tests when input lines are enormously long, pcretest has
1782        been re-factored so that it automatically extends its buffers when
1783        necessary. The code is crude, but this _is_ just a test program. The
1784        default size has been increased from 32K to 50K.
1785    
1786     2. The code in pcre_study() was using the value of the re argument before
1787        testing it for NULL. (Of course, in any sensible call of the function, it
1788        won't be NULL.)
1789    
1790     3. The memmove() emulation function in pcre_internal.h, which is used on
1791        systems that lack both memmove() and bcopy() - that is, hardly ever -
1792        was missing a "static" storage class specifier.
1793    
1794     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1795        containing an extended class (one that cannot be represented by a bitmap
1796        because it contains high-valued characters or Unicode property items, e.g.
1797        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1798        pattern, but PCRE should not loop if you do not (it no longer does).
1799        [Detail: two cases were found: (a) a repeated subpattern containing an
1800        extended class; (b) a recursive reference to a subpattern that followed a
1801        previous extended class. It wasn't skipping over the extended class
1802        correctly when UTF-8 mode was not set.]
1803    
1804     5. A negated single-character class was not being recognized as fixed-length
1805        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1806        compile error "lookbehind assertion is not fixed length".
1807    
1808     6. The RunPerlTest auxiliary script was showing an unexpected difference
1809        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1810        write a Perl script that can interpret lines of an input file either as
1811        byte characters or as UTF-8, which is what "perltest" was being required to
1812        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1813        can't do is switch easily at run time between having the "use utf8;" pragma
1814        or not. In the end, I fudged it by using the RunPerlTest script to insert
1815        "use utf8;" explicitly for the UTF-8 tests.
1816    
1817     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1818        the end of the subject string, contrary to the documentation and to what
1819        Perl does. This was true of both matching functions. Now it matches only at
1820        the start of the subject and immediately after *internal* newlines.
1821    
1822     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1823        a pointer to an int instead of a pointer to an unsigned long int. This
1824        caused problems on 64-bit systems.
1825    
1826     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1827        instance of the 'standard' template library not being so standard".
1828    
1829    10. There was no check on the number of named subpatterns nor the maximum
1830        length of a subpattern name. The product of these values is used to compute
1831        the size of the memory block for a compiled pattern. By supplying a very
1832        long subpattern name and a large number of named subpatterns, the size
1833        computation could be caused to overflow. This is now prevented by limiting
1834        the length of names to 32 characters, and the number of named subpatterns
1835        to 10,000.
1836    
1837    11. Subpatterns that are repeated with specific counts have to be replicated in
1838        the compiled pattern. The size of memory for this was computed from the
1839        length of the subpattern and the repeat count. The latter is limited to
1840        65535, but there was no limit on the former, meaning that integer overflow
1841        could in principle occur. The compiled length of a repeated subpattern is
1842        now limited to 30,000 bytes in order to prevent this.
1843    
1844    12. Added the optional facility to have named substrings with the same name.
1845    
1846    13. Added the ability to use a named substring as a condition, using the
1847        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1848        are numbers (not recommended). Forward references are permitted.
1849    
1850    14. Added forward references in named backreferences (if you see what I mean).
1851    
1852    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1853        pattern could run off the end of the subject. For example, the pattern
1854        "(?s)(.{1,5})"8 did this with the subject "ab".
1855    
1856    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1857        PCRE_CASELESS was set when matching characters that were quantified with ?
1858        or *.
1859    
1860    17. A character class other than a single negated character that had a minimum
1861        but no maximum quantifier - for example [ab]{6,} - was not handled
1862        correctly by pce_dfa_exec(). It would match only one character.
1863    
1864    18. A valid (though odd) pattern that looked like a POSIX character
1865        class but used an invalid character after [ (for example [[,abc,]]) caused
1866        pcre_compile() to give the error "Failed: internal error: code overflow" or
1867        in some cases to crash with a glibc free() error. This could even happen if
1868        the pattern terminated after [[ but there just happened to be a sequence of
1869        letters, a binary zero, and a closing ] in the memory that followed.
1870    
1871    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1872        over the years. Originally (before any Unicode support), just the bottom 8
1873        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1874        output from "man perlunicode" includes this:
1875    
1876          The regular expression compiler produces polymorphic opcodes.  That
1877          is, the pattern adapts to the data and automatically switches to
1878          the Unicode character scheme when presented with Unicode data--or
1879          instead uses a traditional byte scheme when presented with byte
1880          data.
1881    
1882        Sadly, a wide octal escape does not cause a switch, and in a string with
1883        no other multibyte characters, these octal escapes are treated as before.
1884        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1885        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1886        Unicode string.
1887    
1888        I have not perpetrated such confusion in PCRE. Up till now, it took just
1889        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1890        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1891        translate to the appropriate multibyte character.
1892    
1893    29. Applied some refactoring to reduce the number of warnings from Microsoft
1894        and Borland compilers. This has included removing the fudge introduced
1895        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1896        a warning about an unused variable.
1897    
1898    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1899        characters since release 4.0, because Perl (from release 5.004) does not.
1900        [Or at least, is documented not to: some releases seem to be in conflict
1901        with the documentation.] However, when a pattern was studied with
1902        pcre_study() and all its branches started with \s, PCRE still included VT
1903        as a possible starting character. Of course, this did no harm; it just
1904        caused an unnecessary match attempt.
1905    
1906    22. Removed a now-redundant internal flag bit that recorded the fact that case
1907        dependency changed within the pattern. This was once needed for "required
1908        byte" processing, but is no longer used. This recovers a now-scarce options
1909        bit. Also moved the least significant internal flag bit to the most-
1910        significant bit of the word, which was not previously used (hangover from
1911        the days when it was an int rather than a uint) to free up another bit for
1912        the future.
1913    
1914    23. Added support for CRLF line endings as well as CR and LF. As well as the
1915        default being selectable at build time, it can now be changed at runtime
1916        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1917        specify that it is scanning data with non-default line endings.
1918    
1919    24. Changed the definition of CXXLINK to make it agree with the definition of
1920        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1921    
1922    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1923        recursions. This makes a big different to stack usage for some patterns.
1924    
1925    26. If a subpattern containing a named recursion or subroutine reference such
1926        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1927        the space required for the compiled pattern went wrong and gave too small a
1928        value. Depending on the environment, this could lead to "Failed: internal
1929        error: code overflow at offset 49" or "glibc detected double free or
1930        corruption" errors.
1931    
1932    27. Applied patches from Google (a) to support the new newline modes and (b) to
1933        advance over multibyte UTF-8 characters in GlobalReplace.
1934    
1935    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1936        difference for some implementation of PCRE in some Windows version.
1937    
1938    29. Added some extra testing facilities to pcretest:
1939    
1940        \q<number>   in a data line sets the "match limit" value
1941        \Q<number>   in a data line sets the "match recursion limt" value
1942        -S <number>  sets the stack size, where <number> is in megabytes
1943    
1944        The -S option isn't available for Windows.
1945    
1946    
1947    Version 6.6 06-Feb-06
1948    ---------------------
1949    
1950     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1951        in pcreposix.h. I have copied the definition from pcre.h.
1952    
1953     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1954        because pcre.h is no longer a built file.
1955    
1956     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1957        not normally included in the compiled code.
1958    
1959    
1960    Version 6.5 01-Feb-06
1961    ---------------------
1962    
1963     1. When using the partial match feature with pcre_dfa_exec(), it was not
1964        anchoring the second and subsequent partial matches at the new starting
1965        point. This could lead to incorrect results. For example, with the pattern
1966        /1234/, partially matching against "123" and then "a4" gave a match.
1967    
1968     2. Changes to pcregrep:
1969    
1970        (a) All non-match returns from pcre_exec() were being treated as failures
1971            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1972            error message is output. Some extra information is given for the
1973            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1974            probably the only errors that are likely to be caused by users (by
1975            specifying a regex that has nested indefinite repeats, for instance).
1976            If there are more than 20 of these errors, pcregrep is abandoned.
1977    
1978        (b) A binary zero was treated as data while matching, but terminated the
1979            output line if it was written out. This has been fixed: binary zeroes
1980            are now no different to any other data bytes.
1981    
1982        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1983            used to set a locale for matching. The --locale=xxxx long option has
1984            been added (no short equivalent) to specify a locale explicitly on the
1985            pcregrep command, overriding the environment variables.
1986    
1987        (d) When -B was used with -n, some line numbers in the output were one less
1988            than they should have been.
1989    
1990        (e) Added the -o (--only-matching) option.
1991    
1992        (f) If -A or -C was used with -c (count only), some lines of context were
1993            accidentally printed for the final match.
1994    
1995        (g) Added the -H (--with-filename) option.
1996    
1997        (h) The combination of options -rh failed to suppress file names for files
1998            that were found from directory arguments.
1999    
2000        (i) Added the -D (--devices) and -d (--directories) options.
2001    
2002        (j) Added the -F (--fixed-strings) option.
2003    
2004        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2005    
2006        (l) Added the --colo(u)r option.
2007    
2008        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2009            is not present by default.
2010    
2011     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2012        items such as (?R) or (?1), when the recursion could match a number of
2013        alternatives. If it matched one of the alternatives, but subsequently,
2014        outside the recursion, there was a failure, the code tried to back up into
2015        the recursion. However, because of the way PCRE is implemented, this is not
2016        possible, and the result was an incorrect result from the match.
2017    
2018        In order to prevent this happening, the specification of recursion has
2019        been changed so that all such subpatterns are automatically treated as
2020        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2021    
2022     4. I had overlooked the fact that, in some locales, there are characters for
2023        which isalpha() is true but neither isupper() nor islower() are true. In
2024        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2025        and ordfeminine) are like this. This affected the treatment of \w and \W
2026        when they appeared in character classes, but not when they appeared outside
2027        a character class. The bit map for "word" characters is now created
2028        separately from the results of isalnum() instead of just taking it from the
2029        upper, lower, and digit maps. (Plus the underscore character, of course.)
2030    
2031     5. The above bug also affected the handling of POSIX character classes such as
2032        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2033        permanent tables. Instead, the bit maps for such a class were previously
2034        created as the appropriate unions of the upper, lower, and digit bitmaps.
2035        Now they are created by subtraction from the [[:word:]] class, which has
2036        its own bitmap.
2037    
2038     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2039        It is created by subtracting the vertical space characters (\x09, \x0a,
2040        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2041        subtraction was done in the overall bitmap for a character class, meaning
2042        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2043        be recognized. This bug has been fixed.
2044    
2045     7. Patches from the folks at Google:
2046    
2047          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2048          real life, but is still worth protecting against".
2049    
2050          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2051          regular expressions".
2052    
2053          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2054          have it.
2055    
2056          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2057          "configure" and the latter not, in order to fix a problem somebody had
2058          with compiling the Arg class on HP-UX.
2059    
2060          (e) Improve the error-handling of the C++ wrapper a little bit.
2061    
2062          (f) New tests for checking recursion limiting.
2063    
2064     8. The pcre_memmove() function, which is used only if the environment does not
2065        have a standard memmove() function (and is therefore rarely compiled),
2066        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2067        returning a result (though PCRE never actually uses the result).
2068    
2069     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2070        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2071        returned instead of calling malloc() with an overflowing number that would
2072        most likely cause subsequent chaos.
2073    
2074    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2075    
2076    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2077        with this option is matched, the nmatch and pmatch options of regexec() are
2078        ignored.
2079    
2080    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2081        provided in case anyone wants to the the POSIX interface with UTF-8
2082        strings.
2083    
2084    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2085        C++ linking (needed for some HP-UX environments).
2086    
2087    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2088        (unused parameter) and in the pcre_printint() function (omitted "default"
2089        switch label when the default is to do nothing).
2090    
2091    15. Added some code to make it possible, when PCRE is compiled as a C++
2092        library, to replace subject pointers for pcre_exec() with a smart pointer
2093        class, thus making it possible to process discontinuous strings.
2094    
2095    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2096        much the same function. They were added by different people who were trying
2097        to make PCRE easy to compile on non-Unix systems. It has been suggested
2098        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2099        for compiling on Windows systems. I have therefore replaced it with
2100        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2101        defaults to "extern" for C or "extern C" for C++, which works fine on
2102        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2103        SCOPE with something explicit in config.h. In addition:
2104    
2105        (a) pcreposix.h still had just "extern" instead of either of these macros;
2106            I have replaced it with PCRE_DATA_SCOPE.
2107    
2108        (b) Functions such as _pcre_xclass(), which are internal to the library,
2109            but external in the C sense, all had PCRE_EXPORT in their definitions.
2110            This is apparently wrong for the Windows case, so I have removed it.
2111            (It makes no difference on Unix-like systems.)
2112    
2113    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2114        of recursive calls to match(). This is different to MATCH_LIMIT because
2115        that limits the total number of calls to match(), not all of which increase
2116        the depth of recursion. Limiting the recursion depth limits the amount of
2117        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2118        when PCRE is compiled, and changed at run time. A patch from Google adds
2119        this functionality to the C++ interface.
2120    
2121    18. Changes to the handling of Unicode character properties:
2122    
2123        (a) Updated the table to Unicode 4.1.0.
2124    
2125        (b) Recognize characters that are not in the table as "Cn" (undefined).
2126    
2127        (c) I revised the way the table is implemented to a much improved format
2128            which includes recognition of ranges. It now supports the ranges that
2129            are defined in UnicodeData.txt, and it also amalgamates other
2130            characters into ranges. This has reduced the number of entries in the
2131            table from around 16,000 to around 3,000, thus reducing its size
2132            considerably. I realized I did not need to use a tree structure after
2133            all - a binary chop search is just as efficient. Having reduced the
2134            number of entries, I extended their size from 6 bytes to 8 bytes to
2135            allow for more data.
2136    
2137        (d) Added support for Unicode script names via properties such as \p{Han}.
2138    
2139    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2140        matching that character.
2141    
2142    20. When matching a repeated Unicode property with a minimum greater than zero,
2143        (for example \pL{2,}), PCRE could look past the end of the subject if it
2144        reached it while seeking the minimum number of characters. This could
2145        happen only if some of the characters were more than one byte long, because
2146        there is a check for at least the minimum number of bytes.
2147    
2148    21. Refactored the implementation of \p and \P so as to be more general, to
2149        allow for more different types of property in future. This has changed the
2150        compiled form incompatibly. Anybody with saved compiled patterns that use
2151        \p or \P will have to recompile them.
2152    
2153    22. Added "Any" and "L&" to the supported property types.
2154    
2155    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2156        but give a compile time error if the value is greater than 0xff.
2157    
2158    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2159        accidentally not being installed or uninstalled.
2160    
2161    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2162        made were to insert the current release number. This seemed silly, because
2163        it made things harder for people building PCRE on systems that don't run
2164        "configure". I have turned pcre.h into a distributed file, no longer built
2165        by "configure", with the version identification directly included. There is
2166        no longer a pcre.h.in file.
2167    
2168        However, this change necessitated a change to the pcre-config script as
2169        well. It is built from pcre-config.in, and one of the substitutions was the
2170        release number. I have updated configure.ac so that ./configure now finds
2171        the release number by grepping pcre.h.
2172    
2173    26. Added the ability to run the tests under valgrind.
2174    
2175    
2176    Version 6.4 05-Sep-05
2177    ---------------------
2178    
2179     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2180        "--" to be printed when multiple files were scanned, even when none of the
2181        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2182        consider it to be a bug, and have restored the previous behaviour.
2183    
2184     2. A couple of code tidies to get rid of compiler warnings.
2185    
2186     3. The pcretest program used to cheat by referring to symbols in the library
2187        whose names begin with _pcre_. These are internal symbols that are not
2188        really supposed to be visible externally, and in some environments it is
2189        possible to suppress them. The cheating is now confined to including
2190        certain files from the library's source, which is a bit cleaner.
2191    
2192     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2193        file's purpose clearer.
2194    
2195     5. Reorganized pcre_ucp_findchar().
2196    
2197    
2198    Version 6.3 15-Aug-05
2199    ---------------------
2200    
2201     1. The file libpcre.pc.in did not have general read permission in the tarball.
2202    
2203     2. There were some problems when building without C++ support:
2204    
2205        (a) If C++ support was not built, "make install" and "make test" still
2206            tried to test it.
2207    
2208        (b) There were problems when the value of CXX was explicitly set. Some
2209            changes have been made to try to fix these, and ...
2210    
2211        (c) --disable-cpp can now be used to explicitly disable C++ support.
2212    
2213        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2214            backslash in a target when C++ was disabled. This confuses some
2215            versions of "make", apparently. Using an intermediate variable solves
2216            this. (Same for CPP_LOBJ.)
2217    
2218     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2219        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2220        necessary on certain architectures.
2221    
2222     4. Added a setting of -export-symbols-regex to the link command to remove
2223        those symbols that are exported in the C sense, but actually are local
2224        within the library, and not documented. Their names all begin with
2225        "_pcre_". This is not a perfect job, because (a) we have to except some
2226        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2227        available (and never for static libraries). I have made a note to try to
2228        find a way round (a) in the future.
2229    
2230    
2231    Version 6.2 01-Aug-05
2232    ---------------------
2233    
2234     1. There was no test for integer overflow of quantifier values. A construction
2235        such as {1111111111111111} would give undefined results. What is worse, if
2236        a minimum quantifier for a parenthesized subpattern overflowed and became
2237        negative, the calculation of the memory size went wrong. This could have
2238        led to memory overwriting.
2239    
2240     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2241    
2242     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2243        operating environments where this matters.
2244    
2245     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2246        PCRE options from within the C++ wrapper.
2247    
2248     5. Named capturing subpatterns were not being correctly counted when a pattern
2249        was compiled. This caused two problems: (a) If there were more than 100
2250        such subpatterns, the calculation of the memory needed for the whole
2251        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2252        back references of the form \12, where the number was greater than 9, were
2253        not recognized as back references, even though there were sufficient
2254        previous subpatterns.
2255    
2256     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2257        versions of gcc, e.g. 2.95.4.
2258    
2259    
2260    Version 6.1 21-Jun-05
2261    ---------------------
2262    
2263     1. There was one reference to the variable "posix" in pcretest.c that was not
2264        surrounded by "#if !defined NOPOSIX".
2265    
2266     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2267        the cross-check on the old pcre_info() function, for the benefit of the
2268        cut-down version of PCRE that is currently imported into Exim.
2269    
2270     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2271        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2272        patterns that start (?i) but I don't think that matters. The use of (?i) is
2273        just an example; this all applies to the other options as well.
2274    
2275     4. Since libtool seems to echo the compile commands it is issuing, the output
2276        from "make" can be reduced a bit by putting "@" in front of each libtool
2277        compile command.
2278    
2279     5. Patch from the folks at Google for configure.in to be a bit more thorough
2280        in checking for a suitable C++ installation before trying to compile the
2281        C++ stuff. This should fix a reported problem when a compiler was present,
2282        but no suitable headers.
2283    
2284     6. The man pages all had just "PCRE" as their title. I have changed them to
2285        be the relevant file name. I have also arranged that these names are
2286        retained in the file doc/pcre.txt, which is a concatenation in text format
2287        of all the man pages except the little individual ones for each function.
2288    
2289     7. The NON-UNIX-USE file had not been updated for the different set of source
2290        files that come with release 6. I also added a few comments about the C++
2291        wrapper.
2292    
2293    
2294    Version 6.0 07-Jun-05
2295    ---------------------
2296    
2297     1. Some minor internal re-organization to help with my DFA experiments.
2298    
2299     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2300        didn't matter for the library itself when fully configured, but did matter
2301        when compiling without UCP support, or within Exim, where the ucp files are
2302        not imported.
2303    
2304     3. Refactoring of the library code to split up the various functions into
2305        different source modules. The addition of the new DFA matching code (see
2306        below) to a single monolithic source would have made it really too
2307        unwieldy, quite apart from causing all the code to be include in a
2308        statically linked application, when only some functions are used. This is
2309        relevant even without the DFA addition now that patterns can be compiled in
2310        one application and matched in another.
2311    
2312        The downside of splitting up is that there have to be some external
2313        functions and data tables that are used internally in different modules of
2314        the library but which are not part of the API. These have all had their
2315        names changed to start with "_pcre_" so that they are unlikely to clash
2316        with other external names.
2317    
2318     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2319        a different (DFA) algorithm. Although it is slower than the original
2320        function, it does have some advantages for certain types of matching
2321        problem.
2322    
2323     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2324        including restarting after a partial match.
2325    
2326     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2327        defined when compiling for Windows was sent to me. I have put it into the
2328        code, though I have no means of testing or verifying it.
2329    
2330     7. Added the pcre_refcount() auxiliary function.
2331    
2332     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2333        match before or at the first newline in the subject string. In pcretest,
2334        the /f option on a pattern can be used to set this.
2335    
2336     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2337        would behave wrongly. This has been present in PCRE since release 4.0.
2338    
2339    10. A number of changes to the pcregrep command:
2340    
2341        (a) Refactored how -x works; insert ^(...)$ instead of setting
2342            PCRE_ANCHORED and checking the length, in preparation for adding
2343            something similar for -w.
2344    
2345        (b) Added the -w (match as a word) option.
2346    
2347        (c) Refactored the way lines are read and buffered so as to have more
2348            than one at a time available.
2349    
2350        (d) Implemented a pcregrep test script.
2351    
2352        (e) Added the -M (multiline match) option. This allows patterns to match
2353            over several lines of the subject. The buffering ensures that at least
2354            8K, or the rest of the document (whichever is the shorter) is available
2355            for matching (and similarly the previous 8K for lookbehind assertions).
2356    
2357        (f) Changed the --help output so that it now says
2358    
2359              -w, --word-regex(p)
2360    
2361            instead of two lines, one with "regex" and the other with "regexp"
2362            because that confused at least one person since the short forms are the
2363            same. (This required a bit of code, as the output is generated
2364            automatically from a table. It wasn't just a text change.)
2365    
2366        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2367            option but starts with a hyphen. Could be a pattern or a path name
2368            starting with a hyphen, for instance.
2369    
2370        (h) "-" can be given as a file name to represent stdin.
2371    
2372        (i) When file names are being printed, "(standard input)" is used for
2373            the standard input, for compatibility with GNU grep. Previously
2374            "<stdin>" was used.
2375    
2376        (j) The option --label=xxx can be used to supply a name to be used for
2377            stdin when file names are being printed. There is no short form.
2378    
2379        (k) Re-factored the options decoding logic because we are going to add
2380            two more options that take data. Such options can now be given in four
2381            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2382    
2383        (l) Added the -A, -B, and -C options for requesting that lines of context
2384            around matches be printed.
2385    
2386        (m) Added the -L option to print the names of files that do not contain
2387            any matching lines, that is, the complement of -l.
2388    
2389        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2390            continue to scan other files.
2391    
2392        (o) The -s option was incorrectly implemented. For compatibility with other
2393            greps, it now suppresses the error message for a non-existent or non-
2394            accessible file (but not the return code). There is a new option called
2395            -q that suppresses the output of matching lines, which was what -s was
2396            previously doing.
2397    
2398        (p) Added --include and --exclude options to specify files for inclusion
2399            and exclusion when recursing.
2400    
2401    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2402        Hopefully, it now does.
2403    
2404    12. Missing cast in pcre_study().
2405    
2406    13. Added an "uninstall" target to the makefile.
2407    
2408    14. Replaced "extern" in the function prototypes in Makefile.in with
2409        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2410        world, but is set differently for Windows.
2411    
2412    15. Added a second compiling function called pcre_compile2(). The only
2413        difference is that it has an extra argument, which is a pointer to an
2414        integer error code. When there is a compile-time failure, this is set
2415        non-zero, in addition to the error test pointer being set to point to an
2416        error message. The new argument may be NULL if no error number is required
2417        (but then you may as well call pcre_compile(), which is now just a
2418        wrapper). This facility is provided because some applications need a
2419        numeric error indication, but it has also enabled me to tidy up the way
2420        compile-time errors are handled in the POSIX wrapper.
2421    
2422    16. Added VPATH=.libs to the makefile; this should help when building with one
2423        prefix path and installing with another. (Or so I'm told by someone who
2424        knows more about this stuff than I do.)
2425    
2426    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2427        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2428        match everything, including newlines. This is not POSIX-compatible, but
2429        somebody wanted the feature. From pcretest it can be activated by using
2430        both the P and the s flags.
2431    
2432    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2433    
2434    19. libpcre.pc was being incorrectly installed as executable.
2435    
2436    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2437        it now also looks for '\r' so that it will work unmodified on Windows.
2438    
2439    21. Added Google's contributed C++ wrapper to the distribution.
2440    
2441    22. Added some untidy missing memory free() calls in pcretest, to keep
2442        Electric Fence happy when testing.
2443    
2444    
2445    
2446    Version 5.0 13-Sep-04
2447    ---------------------
2448    
2449     1. Internal change: literal characters are no longer packed up into items
2450        containing multiple characters in a single byte-string. Each character
2451        is now matched using a separate opcode. However, there may be more than one
2452        byte in the character in UTF-8 mode.
2453    
2454     2. The pcre_callout_block structure has two new fields: pattern_position and
2455        next_item_length. These contain the offset in the pattern to the next match
2456        item, and its length, respectively.
2457    
2458     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2459        insertion of callouts before each pattern item. Added the /C option to
2460        pcretest to make use of this.
2461    
2462     4. On the advice of a Windows user, the lines
2463    
2464          #if defined(_WIN32) || defined(WIN32)
2465          _setmode( _fileno( stdout ), 0x8000 );
2466          #endif  /* defined(_WIN32) || defined(WIN32) */
2467    
2468        have been added to the source of pcretest. This apparently does useful
2469        magic in relation to line terminators.
2470    
2471     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2472        for the benefit of those environments where the "b" makes a difference.
2473    
2474     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2475        to know about it. I have put a hack into configure.in that adds in code
2476        to set GCC=yes if CC=icc. This seems to end up at a point in the
2477        generated configure script that is early enough to affect the setting of
2478        compiler options, which is what is needed, but I have no means of testing
2479        whether it really works. (The user who reported this had patched the
2480        generated configure script, which of course I cannot do.)
2481    
2482        LATER: After change 22 below (new libtool files), the configure script
2483        seems to know about icc (and also ecc). Therefore, I have commented out
2484        this hack in configure.in.
2485    
2486     7. Added support for pkg-config (2 patches were sent in).
2487    
2488     8. Negated POSIX character classes that used a combination of internal tables
2489        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2490        [[:^ascii]]. Typically, they would match almost any characters. The other
2491        POSIX classes were not broken in this way.
2492    
2493     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2494        to find the match, as PCRE was deluded into thinking that the match had to
2495        start at the start point or following a newline. The same bug applied to
2496        patterns with negative forward assertions or any backward assertions
2497        preceding ".*" at the start, unless the pattern required a fixed first
2498        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2499    
2500    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2501        starting at the last subject character, bytes beyond the end of the subject
2502        string were read.
2503    
2504    11. Renamed the variable "class" as "classbits" to make life easier for C++
2505        users. (Previously there was a macro definition, but it apparently wasn't
2506        enough.)
2507    
2508    12. Added the new field "tables" to the extra data so that tables can be passed
2509        in at exec time, or the internal tables can be re-selected. This allows
2510        a compiled regex to be saved and re-used at a later time by a different
2511        program that might have everything at different addresses.
2512    
2513    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2514        -R library as well as a -L library.
2515    
2516    14. The debugging options of pcretest (-d on the command line or D on a
2517        pattern) showed incorrect output for anything following an extended class
2518        that contained multibyte characters and which was followed by a quantifier.
2519    
2520    15. Added optional support for general category Unicode character properties
2521        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2522        support. It adds about 90K to the size of the library. The meanings of the
2523        inbuilt class escapes such as \d and \s have NOT been changed.
2524    
2525    16. Updated pcredemo.c to include calls to free() to release the memory for the
2526        compiled pattern.
2527    
2528    17. The generated file chartables.c was being created in the source directory
2529        instead of in the building directory. This caused the build to fail if the
2530        source directory was different from the building directory, and was
2531        read-only.
2532    
2533    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2534        file. No doubt somebody will tell me if they don't make sense... Also added
2535        Dan Mooney's comments about building on OpenVMS.
2536    
2537    19. Added support for partial matching via the PCRE_PARTIAL option for
2538        pcre_exec() and the \P data escape in pcretest.
2539    
2540    20. Extended pcretest with 3 new pattern features:
2541    
2542        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2543              write the compiled pattern to the file whose name is "rest-of-line".
2544              This is a straight binary dump of the data, with the saved pointer to
2545              the character tables forced to be NULL. The study data, if any, is
2546              written too. After writing, pcretest reads a new pattern.
2547    
2548        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2549              compiled pattern from the given file. There must not be any
2550              occurrences of "<" in the file name (pretty unlikely); if there are,
2551              pcretest will instead treat the initial "<" as a pattern delimiter.
2552              After reading in the pattern, pcretest goes on to read data lines as
2553              usual.
2554    
2555        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2556              and 16-bit fields in a compiled pattern, to simulate a pattern that
2557              was compiled on a host of opposite endianness.
2558    
2559    21. The pcre-exec() function can now cope with patterns that were compiled on
2560        hosts of opposite endianness, with this restriction:
2561    
2562          As for any compiled expression that is saved and used later, the tables
2563          pointer field cannot be preserved; the extra_data field in the arguments
2564          to pcre_exec() should be used to pass in a tables address if a value
2565          other than the default internal tables were used at compile time.
2566    
2567    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2568        now diagnosed as an error. Previously, most of the time, a negative number
2569        would have been treated as zero, but if in addition "ovector" was passed as
2570        NULL, a crash could occur.
2571    
2572    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2573        new versions from the libtool 1.5 distribution (the last one is a copy of
2574        a file called libtool.m4). This seems to have fixed the need to patch
2575        "configure" to support Darwin 1.3 (which I used to do). However, I still
2576        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2577        workstation).
2578    
2579    24. Changed the PCRE licence to be the more standard "BSD" licence.
2580    
2581    
2582    Version 4.5 01-Dec-03
2583    ---------------------
2584    
2585     1. There has been some re-arrangement of the code for the match() function so
2586        that it can be compiled in a version that does not call itself recursively.
2587        Instead, it keeps those local variables that need separate instances for
2588        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2589        needs to "recurse". Keeping track of where control must go is done by means
2590        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2591        hide most of the details from the main code, and operates only if
2592        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2593        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2594        operating.
2595    
2596        To make it easier for callers to provide specially tailored get/free
2597        functions for this usage, two new functions, pcre_stack_malloc, and
2598        pcre_stack_free, are used. They are always called in strict stacking order,
2599        and the size of block requested is always the same.
2600    
2601        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2602        PCRE has been compiled to use the stack or the heap for recursion. The
2603        -C option of pcretest uses this to show which version is compiled.
2604    
2605        A new data escape \S, is added to pcretest; it causes the amounts of store
2606        obtained and freed by both kinds of malloc/free at match time to be added
2607        to the output.
2608    
2609     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2610        what's available on my current Linux desktop machine.
2611    
2612     3. When matching a UTF-8 string, the test for a valid string at the start has
2613        been extended. If start_offset is not zero, PCRE now checks that it points
2614        to a byte that is the start of a UTF-8 character. If not, it returns
2615        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2616        this is necessary because there may be backward assertions in the pattern.
2617        When matching the same subject several times, it may save resources to use
2618        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2619    
2620     4. The code for checking the validity of UTF-8 strings has been tightened so
2621        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2622        containing "overlong sequences".
2623    
2624     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2625        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2626        should have been "&", but it just so happened that all the cases this let
2627        through by mistake were picked up later in the function.
2628    
2629     6. I had used a variable called "isblank" - this is a C99 function, causing
2630        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2631    
2632     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2633        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2634        so the version is shown; (c) stop "make test" echoing "./RunTest".
2635    
2636     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2637    
2638     9. The prototype for memmove() for systems that don't have it was using
2639        size_t, but the inclusion of the header that defines size_t was later. I've
2640        moved the #includes for the C headers earlier to avoid this.
2641    
2642    10. Added some adjustments to the code to make it easier to compiler on certain
2643        special systems:
2644    
2645          (a) Some "const" qualifiers were missing.
2646          (b) Added the macro EXPORT before all exported functions; by default this
2647              is defined to be empty.
2648          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2649              that it reads its output file name as an argument instead of writing
2650              to the standard output and assuming this can be redirected.
2651    
2652    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2653        class containing characters with values greater than 255, PCRE compilation
2654        went into a loop.
2655    
2656    12. A recursive reference to a subpattern that was within another subpattern
2657        that had a minimum quantifier of zero caused PCRE to crash. For example,
2658        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2659        recursion. If the recursively-called subpattern itself had a zero repeat,
2660        that was OK.
2661    
2662    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2663        buffer into which it was copied (for escape processing) was still set at
2664        1024, so long lines caused crashes.
2665    
2666    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2667        "internal error: code overflow...". This applied to any character class
2668        that was followed by a possessive quantifier.
2669    
2670    15. Modified the Makefile to add libpcre.la as a prerequisite for
2671        libpcreposix.la because I was told this is needed for a parallel build to
2672        work.
2673    
2674    16. If a pattern that contained .* following optional items at the start was
2675        studied, the wrong optimizing data was generated, leading to matching
2676        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2677        matching string must start with a or b or c. The correct conclusion for
2678        this pattern is that a match can start with any character.
2679    
2680    
2681  Version 4.4 13-Aug-03  Version 4.4 13-Aug-03
2682  ---------------------  ---------------------
2683    

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