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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
14    
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
23    
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
28    
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
34    
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
38    
39    
40    
41    Version 8.12 15-Jan-2011
42    ------------------------
43    
44    1.  Fixed some typos in the markup of the man pages, and wrote a script that
45        checks for such things as part of the documentation building process.
46    
47    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
48        --match-limit and --recursion-limit options (added for 8.11). In
49        particular, this made one of the standard tests fail. (The integer value
50        went into the wrong half of a long int.)
51    
52    3.  If the --colour option was given to pcregrep with -v (invert match), it
53        did strange things, either producing crazy output, or crashing. It should,
54        of course, ignore a request for colour when reporting lines that do not
55        match.
56    
57    4.  Another pcregrep bug caused similar problems if --colour was specified with
58        -M (multiline) and the pattern match finished with a line ending.
59    
60    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
61        matched in multiline mode, the following line was shown as part of the
62        match. This seems wrong, so I have changed it.
63    
64    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
65        the check for further matches in the same line (so they could be coloured)
66        to overrun the end of the current line. If another match was found, it was
67        incorrectly shown (and then shown again when found in the next line).
68    
69    7.  If pcregrep was compiled under Windows, there was a reference to the
70        function pcregrep_exit() before it was defined. I am assuming this was
71        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
72        reported by a user. I've moved the definition above the reference.
73    
74    
75    Version 8.11 10-Dec-2010
76    ------------------------
77    
78    1.  (*THEN) was not working properly if there were untried alternatives prior
79        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
80        backtracked to try for "b" instead of moving to the next alternative branch
81        at the same level (in this case, to look for "c"). The Perl documentation
82        is clear that when (*THEN) is backtracked onto, it goes to the "next
83        alternative in the innermost enclosing group".
84    
85    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
86        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
87        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
88        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
89        (*THEN).
90    
91    3.  If \s appeared in a character class, it removed the VT character from
92        the class, even if it had been included by some previous item, for example
93        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
94        of \s, but is part of the POSIX "space" class.)
95    
96    4.  A partial match never returns an empty string (because you can always
97        match an empty string at the end of the subject); however the checking for
98        an empty string was starting at the "start of match" point. This has been
99        changed to the "earliest inspected character" point, because the returned
100        data for a partial match starts at this character. This means that, for
101        example, /(?<=abc)def/ gives a partial match for the subject "abc"
102        (previously it gave "no match").
103    
104    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
105        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
106        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
107        has an implication that the given string is incomplete (because a partial
108        match is preferred over a full match). For this reason, these items now
109        give a partial match in this situation. [Aside: previously, the one case
110        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
111        match rather than a full match, which was wrong by the old rules, but is
112        now correct.]
113    
114    6.  There was a bug in the handling of #-introduced comments, recognized when
115        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
116        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
117        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
118        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
119        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
120        places in pcre_compile().
121    
122    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
123        comments when looking ahead for named forward references to subpatterns,
124        the only newline sequence it recognized was NL. It now handles newlines
125        according to the set newline convention.
126    
127    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
128        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
129        cater for a lack of strerror(). These oversights have been fixed.
130    
131    9.  Added --match-limit and --recursion-limit to pcregrep.
132    
133    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
134    
135    11. When the -o option was used, pcregrep was setting a return code of 1, even
136        when matches were found, and --line-buffered was not being honoured.
137    
138    12. Added an optional parentheses number to the -o and --only-matching options
139        of pcregrep.
140    
141    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
142        can match an empty string. The code to do it in pcretest and pcredemo
143        needed fixing:
144    
145        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
146            only one byte after an empty string match just before CRLF (this case
147            just got forgotten; "any" and "anycrlf" were OK).
148    
149        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
150            mode when an empty string match preceded an ASCII character followed by
151            a non-ASCII character. (The code for advancing by one character rather
152            than one byte was nonsense.)
153    
154        (c) The pcredemo.c sample program did not have any code at all to handle
155            the cases when CRLF is a valid newline sequence.
156    
157    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
158        as a starting offset was within the subject string. There is now a new
159        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
160        negative or greater than the length of the string. In order to test this,
161        pcretest is extended to allow the setting of negative starting offsets.
162    
163    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
164        starting offset points to the beginning of a UTF-8 character was
165        unnecessarily clumsy. I tidied it up.
166    
167    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
168        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
169    
170    17. Nobody had reported that the --include_dir option, which was added in
171        release 7.7 should have been called --include-dir (hyphen, not underscore)
172        for compatibility with GNU grep. I have changed it to --include-dir, but
173        left --include_dir as an undocumented synonym, and the same for
174        --exclude-dir, though that is not available in GNU grep, at least as of
175        release 2.5.4.
176    
177    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
178        characters from a string of bytes) have been redefined so as not to use
179        loops, in order to improve performance in some environments. At the same
180        time, I abstracted some of the common code into auxiliary macros to save
181        repetition (this should not affect the compiled code).
182    
183    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
184        compile-time error is now given if \c is not followed by an ASCII
185        character, that is, a byte less than 128. (In EBCDIC mode, the code is
186        different, and any byte value is allowed.)
187    
188    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
189        START_OPTIMIZE option, which is now allowed at compile time - but just
190        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
191        to pcregrep and other applications that have no direct access to PCRE
192        options. The new /Y option in pcretest sets this option when calling
193        pcre_compile().
194    
195    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
196        back references. Groups containing recursive back references were forced to
197        be atomic by that change, but in the case of named groups, the amount of
198        memory required was incorrectly computed, leading to "Failed: internal
199        error: code overflow". This has been fixed.
200    
201    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
202        pcretest.c, to avoid build problems in some Borland environments.
203    
204    
205    Version 8.10 25-Jun-2010
206    ------------------------
207    
208    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
209        THEN.
210    
211    2.  (*ACCEPT) was not working when inside an atomic group.
212    
213    3.  Inside a character class, \B is treated as a literal by default, but
214        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
215        causes the error). The code is unchanged, but I tidied the documentation.
216    
217    4.  Inside a character class, PCRE always treated \R and \X as literals,
218        whereas Perl faults them if its -w option is set. I have changed PCRE so
219        that it faults them when PCRE_EXTRA is set.
220    
221    5.  Added support for \N, which always matches any character other than
222        newline. (It is the same as "." when PCRE_DOTALL is not set.)
223    
224    6.  When compiling pcregrep with newer versions of gcc which may have
225        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
226        declared with attribute warn_unused_result" were given. Just casting the
227        result to (void) does not stop the warnings; a more elaborate fudge is
228        needed. I've used a macro to implement this.
229    
230    7.  Minor change to pcretest.c to avoid a compiler warning.
231    
232    8.  Added four artifical Unicode properties to help with an option to make
233        \s etc use properties (see next item). The new properties are: Xan
234        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
235    
236    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
237        use Unicode properties. (*UCP) at the start of a pattern can be used to set
238        this option. Modified pcretest to add /W to test this facility. Added
239        REG_UCP to make it available via the POSIX interface.
240    
241    10. Added --line-buffered to pcregrep.
242    
243    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
244        studied, and the match started with a letter with a code point greater than
245        127 whose first byte was different to the first byte of the other case of
246        the letter, the other case of this starting letter was not recognized
247        (#976).
248    
249    12. If a pattern that was studied started with a repeated Unicode property
250        test, for example, \p{Nd}+, there was the theoretical possibility of
251        setting up an incorrect bitmap of starting bytes, but fortunately it could
252        not have actually happened in practice until change 8 above was made (it
253        added property types that matched character-matching opcodes).
254    
255    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
256        possible starting bytes for non-anchored patterns.
257    
258    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
259        \R, and also a number of cases that involve Unicode properties, both
260        explicit and implicit when PCRE_UCP is set.
261    
262    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
263        input, it could crash or give wrong results if characters with values
264        greater than 0xc0 were present in the subject string. (Detail: it assumed
265        UTF-8 input when processing these items.)
266    
267    16. Added a lot of (int) casts to avoid compiler warnings in systems where
268        size_t is 64-bit (#991).
269    
270    17. Added a check for running out of memory when PCRE is compiled with
271        --disable-stack-for-recursion (#990).
272    
273    18. If the last data line in a file for pcretest does not have a newline on
274        the end, a newline was missing in the output.
275    
276    19. The default pcre_chartables.c file recognizes only ASCII characters (values
277        less than 128) in its various bitmaps. However, there is a facility for
278        generating tables according to the current locale when PCRE is compiled. It
279        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
280        characters, are recognized by isspace() and therefore were getting set in
281        these tables, and indeed these tables seem to approximate to ISO 8859. This
282        caused a problem in UTF-8 mode when pcre_study() was used to create a list
283        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
284        which of course cannot start UTF-8 characters. I have changed the code so
285        that only real ASCII characters (less than 128) and the correct starting
286        bytes for UTF-8 encodings are set for characters greater than 127 when in
287        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
288        altogether.)
289    
290    20. Added the /T option to pcretest so as to be able to run tests with non-
291        standard character tables, thus making it possible to include the tests
292        used for 19 above in the standard set of tests.
293    
294    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
295        reference to a subpattern the other side of a comment that contains an
296        opening parenthesis caused either an internal compiling error, or a
297        reference to the wrong subpattern.
298    
299    
300    Version 8.02 19-Mar-2010
301    ------------------------
302    
303    1.  The Unicode data tables have been updated to Unicode 5.2.0.
304    
305    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
306        configured.
307    
308    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
309        original author of that file, following a query about its status.
310    
311    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
312        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
313    
314    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
315        quantifier applied to a forward-referencing subroutine call, could compile
316        incorrect code or give the error "internal error: previously-checked
317        referenced subpattern not found".
318    
319    6.  Both MS Visual Studio and Symbian OS have problems with initializing
320        variables to point to external functions. For these systems, therefore,
321        pcre_malloc etc. are now initialized to local functions that call the
322        relevant global functions.
323    
324    7.  There were two entries missing in the vectors called coptable and poptable
325        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
326        I've fixed the data, and added a kludgy way of testing at compile time that
327        the lengths are correct (equal to the number of opcodes).
328    
329    8.  Following on from 7, I added a similar kludge to check the length of the
330        eint vector in pcreposix.c.
331    
332    9.  Error texts for pcre_compile() are held as one long string to avoid too
333        much relocation at load time. To find a text, the string is searched,
334        counting zeros. There was no check for running off the end of the string,
335        which could happen if a new error number was added without updating the
336        string.
337    
338    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
339    
340    11. \K was not working if it appeared in an atomic group or in a group that
341        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
342        \K is "not well defined" if used in an assertion. PCRE now accepts it if
343        the assertion is positive, but not if it is negative.
344    
345    12. Change 11 fortuitously reduced the size of the stack frame used in the
346        "match()" function of pcre_exec.c by one pointer. Forthcoming
347        implementation of support for (*MARK) will need an extra pointer on the
348        stack; I have reserved it now, so that the stack frame size does not
349        decrease.
350    
351    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
352        item in branch that calls a recursion is a subroutine call - as in the
353        second branch in the above example - was incorrectly given the compile-
354        time error "recursive call could loop indefinitely" because pcre_compile()
355        was not correctly checking the subroutine for matching a non-empty string.
356    
357    14. The checks for overrunning compiling workspace could trigger after an
358        overrun had occurred. This is a "should never occur" error, but it can be
359        triggered by pathological patterns such as hundreds of nested parentheses.
360        The checks now trigger 100 bytes before the end of the workspace.
361    
362    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
363    
364    
365    Version 8.01 19-Jan-2010
366    ------------------------
367    
368    1.  If a pattern contained a conditional subpattern with only one branch (in
369        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
370        computed the wrong minimum data length (which is of course zero for such
371        subpatterns). This could cause incorrect "no match" results.
372    
373    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
374        the pattern is reset in the first branch, pcre_compile() failed with
375        "internal error: code overflow at offset...". This happened only when
376        the reset was to the original external option setting. (An optimization
377        abstracts leading options settings into an external setting, which was the
378        cause of this.)
379    
380    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
381        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
382        assertion pattern did not match (meaning that the assertion was true), it
383        was incorrectly treated as false if the SKIP had been reached during the
384        matching. This also applied to assertions used as conditions.
385    
386    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
387        assertion subpattern, including such a pattern used as a condition,
388        unpredictable results occurred, instead of the error return
389        PCRE_ERROR_DFA_UITEM.
390    
391    5.  The C++ GlobalReplace function was not working like Perl for the special
392        situation when an empty string is matched. It now does the fancy magic
393        stuff that is necessary.
394    
395    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
396        removed. (These were left over from very, very early versions of PCRE.)
397    
398    7.  Some cosmetic changes to the code to make life easier when compiling it
399        as part of something else:
400    
401        (a) Change DEBUG to PCRE_DEBUG.
402    
403        (b) In pcre_compile(), rename the member of the "branch_chain" structure
404            called "current" as "current_branch", to prevent a collision with the
405            Linux macro when compiled as a kernel module.
406    
407        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
408            prevent a collision with the Linux macro when compiled as a kernel
409            module.
410    
411    8.  In pcre_compile() there are some checks for integer overflows that used to
412        cast potentially large values to (double). This has been changed to that
413        when building, a check for int64_t is made, and if it is found, it is used
414        instead, thus avoiding the use of floating point arithmetic. (There is no
415        other use of FP in PCRE.) If int64_t is not found, the fallback is to
416        double.
417    
418    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
419        2005 (difference between two addresses compared to an unsigned value).
420    
421    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
422        custom one, because of the following reported problem in Windows:
423    
424          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
425              under Win32.
426          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
427              therefore missing the function definition.
428          - The compiler thus generates a "C" signature for the test function.
429          - The linker fails to find the "C" function.
430          - PCRE fails to configure if asked to do so against libbz2.
431    
432    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
433        messages were output:
434    
435          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
436          rerunning libtoolize, to keep the correct libtool macros in-tree.
437          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
438    
439        I have done both of these things.
440    
441    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
442        most of the time, it *can* run out if it is given a pattern that contains a
443        runaway infinite recursion. I updated the discussion in the pcrestack man
444        page.
445    
446    13. Now that we have gone to the x.xx style of version numbers, the minor
447        version may start with zero. Using 08 or 09 is a bad idea because users
448        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
449        interpreted as invalid octal numbers. I've updated the previous comment in
450        configure.ac, and also added a check that gives an error if 08 or 09 are
451        used.
452    
453    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
454        causing partial matching to fail when the end of the subject matched \W
455        in a UTF-8 pattern where \W was quantified with a minimum of 3.
456    
457    15. There were some discrepancies between the declarations in pcre_internal.h
458        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
459        their definitions. The declarations used "const uschar *" and the
460        definitions used USPTR. Even though USPTR is normally defined as "const
461        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
462        reported that: "This difference in casting confuses some C++ compilers, for
463        example, SunCC recognizes above declarations as different functions and
464        generates broken code for hbpcre." I have changed the declarations to use
465        USPTR.
466    
467    16. GNU libtool is named differently on some systems. The autogen.sh script now
468        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
469        (FreeBSD).
470    
471    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
472        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
473        comment: "Figure out how to create a longlong from a string: strtoll and
474        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
475        instance, but it only takes 2 args instead of 3!"
476    
477    18. A subtle bug concerned with back references has been fixed by a change of
478        specification, with a corresponding code fix. A pattern such as
479        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
480        refers, was giving matches when it shouldn't. For example, xa=xaaa would
481        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
482        same bug. Such groups have to be quantified to be useful, or contained
483        inside another quantified group. (If there's no repetition, the reference
484        can never match.) The problem arises because, having left the group and
485        moved on to the rest of the pattern, a later failure that backtracks into
486        the group uses the captured value from the final iteration of the group
487        rather than the correct earlier one. I have fixed this in PCRE by forcing
488        any group that contains a reference to itself to be an atomic group; that
489        is, there cannot be any backtracking into it once it has completed. This is
490        similar to recursive and subroutine calls.
491    
492    
493    Version 8.00 19-Oct-09
494    ----------------------
495    
496    1.  The table for translating pcre_compile() error codes into POSIX error codes
497        was out-of-date, and there was no check on the pcre_compile() error code
498        being within the table. This could lead to an OK return being given in
499        error.
500    
501    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
502        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
503        in a Windows environment.
504    
505    3.  The pcregrep --count option prints the count for each file even when it is
506        zero, as does GNU grep. However, pcregrep was also printing all files when
507        --files-with-matches was added. Now, when both options are given, it prints
508        counts only for those files that have at least one match. (GNU grep just
509        prints the file name in this circumstance, but including the count seems
510        more useful - otherwise, why use --count?) Also ensured that the
511        combination -clh just lists non-zero counts, with no names.
512    
513    4.  The long form of the pcregrep -F option was incorrectly implemented as
514        --fixed_strings instead of --fixed-strings. This is an incompatible change,
515        but it seems right to fix it, and I didn't think it was worth preserving
516        the old behaviour.
517    
518    5.  The command line items --regex=pattern and --regexp=pattern were not
519        recognized by pcregrep, which required --regex pattern or --regexp pattern
520        (with a space rather than an '='). The man page documented the '=' forms,
521        which are compatible with GNU grep; these now work.
522    
523    6.  No libpcreposix.pc file was created for pkg-config; there was just
524        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
525    
526    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
527        when UCP support is not needed, by modifying the Python script that
528        generates it from Unicode data files. This should not matter if the module
529        is correctly used as a library, but I received one complaint about 50K of
530        unwanted data. My guess is that the person linked everything into his
531        program rather than using a library. Anyway, it does no harm.
532    
533    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
534        was a minimum greater than 1 for a wide character in a possessive
535        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
536        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
537        character. Chaos in the form of incorrect output or a compiling loop could
538        result.
539    
540    9.  The restrictions on what a pattern can contain when partial matching is
541        requested for pcre_exec() have been removed. All patterns can now be
542        partially matched by this function. In addition, if there are at least two
543        slots in the offset vector, the offset of the earliest inspected character
544        for the match and the offset of the end of the subject are set in them when
545        PCRE_ERROR_PARTIAL is returned.
546    
547    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
548        synonymous with PCRE_PARTIAL, for backwards compatibility, and
549        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
550        and may be more useful for multi-segment matching.
551    
552    11. Partial matching with pcre_exec() is now more intuitive. A partial match
553        used to be given if ever the end of the subject was reached; now it is
554        given only if matching could not proceed because another character was
555        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
556        string "Z", which now yields "no match" instead of "partial match". In the
557        case of pcre_dfa_exec(), "no match" is given if every matching path for the
558        final character ended with (*FAIL).
559    
560    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
561        if the pattern had a "must contain" character that was already found in the
562        earlier partial match, unless partial matching was again requested. For
563        example, with the pattern /dog.(body)?/, the "must contain" character is
564        "g". If the first part-match was for the string "dog", restarting with
565        "sbody" failed. This bug has been fixed.
566    
567    13. The string returned by pcre_dfa_exec() after a partial match has been
568        changed so that it starts at the first inspected character rather than the
569        first character of the match. This makes a difference only if the pattern
570        starts with a lookbehind assertion or \b or \B (\K is not supported by
571        pcre_dfa_exec()). It's an incompatible change, but it makes the two
572        matching functions compatible, and I think it's the right thing to do.
573    
574    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
575        so that the demonstration program is easily available in environments where
576        PCRE has not been installed from source.
577    
578    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
579        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
580        library.
581    
582    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
583        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
584        is not the first non-POSIX option to be added. Clearly some people find
585        these options useful.
586    
587    17. If a caller to the POSIX matching function regexec() passes a non-zero
588        value for nmatch with a NULL value for pmatch, the value of
589        nmatch is forced to zero.
590    
591    18. RunGrepTest did not have a test for the availability of the -u option of
592        the diff command, as RunTest does. It now checks in the same way as
593        RunTest, and also checks for the -b option.
594    
595    19. If an odd number of negated classes containing just a single character
596        interposed, within parentheses, between a forward reference to a named
597        subpattern and the definition of the subpattern, compilation crashed with
598        an internal error, complaining that it could not find the referenced
599        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
600        [The bug was that it was starting one character too far in when skipping
601        over the character class, thus treating the ] as data rather than
602        terminating the class. This meant it could skip too much.]
603    
604    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
605        /g option in pcretest when the pattern contains \K, which makes it possible
606        to have an empty string match not at the start, even when the pattern is
607        anchored. Updated pcretest and pcredemo to use this option.
608    
609    21. If the maximum number of capturing subpatterns in a recursion was greater
610        than the maximum at the outer level, the higher number was returned, but
611        with unset values at the outer level. The correct (outer level) value is
612        now given.
613    
614    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
615        PCRE did not set those parentheses (unlike Perl). I have now found a way to
616        make it do so. The string so far is captured, making this feature
617        compatible with Perl.
618    
619    23. The tests have been re-organized, adding tests 11 and 12, to make it
620        possible to check the Perl 5.10 features against Perl 5.10.
621    
622    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
623        pattern matches a fixed length string. PCRE did not allow this; now it
624        does. Neither allows recursion.
625    
626    25. I finally figured out how to implement a request to provide the minimum
627        length of subject string that was needed in order to match a given pattern.
628        (It was back references and recursion that I had previously got hung up
629        on.) This code has now been added to pcre_study(); it finds a lower bound
630        to the length of subject needed. It is not necessarily the greatest lower
631        bound, but using it to avoid searching strings that are too short does give
632        some useful speed-ups. The value is available to calling programs via
633        pcre_fullinfo().
634    
635    26. While implementing 25, I discovered to my embarrassment that pcretest had
636        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
637        study optimizations had never been tested with that matching function.
638        Oops. What is worse, even when it was passed study data, there was a bug in
639        pcre_dfa_exec() that meant it never actually used it. Double oops. There
640        were also very few tests of studied patterns with pcre_dfa_exec().
641    
642    27. If (?| is used to create subpatterns with duplicate numbers, they are now
643        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
644        on the other side of the coin, they are no longer allowed to have different
645        names, because these cannot be distinguished in PCRE, and this has caused
646        confusion. (This is a difference from Perl.)
647    
648    28. When duplicate subpattern names are present (necessarily with different
649        numbers, as required by 27 above), and a test is made by name in a
650        conditional pattern, either for a subpattern having been matched, or for
651        recursion in such a pattern, all the associated numbered subpatterns are
652        tested, and the overall condition is true if the condition is true for any
653        one of them. This is the way Perl works, and is also more like the way
654        testing by number works.
655    
656    
657    Version 7.9 11-Apr-09
658    ---------------------
659    
660    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
661        (pcretest), all targets were linked against these libraries. This included
662        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
663        libraries. This caused unwanted dependencies to be created. This problem
664        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
665        pcretest is linked with readline.
666    
667    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
668        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
669        moved outside it again, because FALSE and TRUE are already defined in AIX,
670        but BOOL is not.
671    
672    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
673        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
674    
675    4.  The pcregrep documentation said spaces were inserted as well as colons (or
676        hyphens) following file names and line numbers when outputting matching
677        lines. This is not true; no spaces are inserted. I have also clarified the
678        wording for the --colour (or --color) option.
679    
680    5.  In pcregrep, when --colour was used with -o, the list of matching strings
681        was not coloured; this is different to GNU grep, so I have changed it to be
682        the same.
683    
684    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
685        each matching line was coloured. Now it goes on to look for further matches
686        of any of the test patterns, which is the same behaviour as GNU grep.
687    
688    7.  A pattern that could match an empty string could cause pcregrep to loop; it
689        doesn't make sense to accept an empty string match in pcregrep, so I have
690        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
691        seems to be how GNU grep behaves.
692    
693    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
694        start or after a newline", because the conditional assertion was not being
695        correctly handled. The rule now is that both the assertion and what follows
696        in the first alternative must satisfy the test.
697    
698    9.  If auto-callout was enabled in a pattern with a conditional group whose
699        condition was an assertion, PCRE could crash during matching, both with
700        pcre_exec() and pcre_dfa_exec().
701    
702    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
703        used for matching.
704    
705    11. Unicode property support in character classes was not working for
706        characters (bytes) greater than 127 when not in UTF-8 mode.
707    
708    12. Added the -M command line option to pcretest.
709    
710    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
711    
712    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
713    
714    16. Added comments and documentation about mis-use of no_arg in the C++
715        wrapper.
716    
717    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
718        from Martin Jerabek that uses macro names for all relevant character and
719        string constants.
720    
721    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
722        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
723        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
724        these, but not everybody uses configure.
725    
726    19. A conditional group that had only one branch was not being correctly
727        recognized as an item that could match an empty string. This meant that an
728        enclosing group might also not be so recognized, causing infinite looping
729        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
730        with the subject "ab", where knowledge that the repeated group can match
731        nothing is needed in order to break the loop.
732    
733    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
734        exec(), but without supplying a callout function, matching went wrong.
735    
736    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
737        leak if the size of the offset vector was greater than 30. When the vector
738        is smaller, the saved offsets during recursion go onto a local stack
739        vector, but for larger vectors malloc() is used. It was failing to free
740        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
741        error, in fact).
742    
743    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
744        heapframe that is used only when UTF-8 support is enabled. This caused no
745        problem, but was untidy.
746    
747    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
748        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
749        included within another project.
750    
751    24. Steven Van Ingelgem's patches to add more options to the CMake support,
752        slightly modified by me:
753    
754          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
755              not building pcregrep.
756    
757          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
758              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
759    
760    25. Forward references, both numeric and by name, in patterns that made use of
761        duplicate group numbers, could behave incorrectly or give incorrect errors,
762        because when scanning forward to find the reference group, PCRE was not
763        taking into account the duplicate group numbers. A pattern such as
764        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
765    
766    26. Changed a few more instances of "const unsigned char *" to USPTR, making
767        the feature of a custom pointer more persuasive (as requested by a user).
768    
769    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
770        pcretest.c, inside #ifndefs, because it seems they are sometimes already
771        pre-defined.
772    
773    28. Added support for (*UTF8) at the start of a pattern.
774    
775    29. Arrange for flags added by the "release type" setting in CMake to be shown
776        in the configuration summary.
777    
778    
779    Version 7.8 05-Sep-08
780    ---------------------
781    
782    1.  Replaced UCP searching code with optimized version as implemented for Ad
783        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
784        stage table and inline lookup instead of a function, giving speed ups of 2
785        to 5 times on some simple patterns that I tested. Permission was given to
786        distribute the MultiStage2.py script that generates the tables (it's not in
787        the tarball, but is in the Subversion repository).
788    
789    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
790        scripts.
791    
792    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
793        a group with a zero qualifier. The result of the study could be incorrect,
794        or the function might crash, depending on the pattern.
795    
796    4.  Caseless matching was not working for non-ASCII characters in back
797        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
798        It now works when Unicode Property Support is available.
799    
800    5.  In pcretest, an escape such as \x{de} in the data was always generating
801        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
802        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
803        truncation.
804    
805    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
806    
807    7.  Added two (int) casts to pcregrep when printing the difference of two
808        pointers, in case they are 64-bit values.
809    
810    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
811        test 2 if it fails.
812    
813    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
814        and a #define of that name to empty if it is not externally set. This is to
815        allow users of MSVC to set it if necessary.
816    
817    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
818        the convenience functions in the pcre_get.c source file.
819    
820    11. An option change at the start of a pattern that had top-level alternatives
821        could cause overwriting and/or a crash. This command provoked a crash in
822        some environments:
823    
824          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
825    
826        This potential security problem was recorded as CVE-2008-2371.
827    
828    12. For a pattern where the match had to start at the beginning or immediately
829        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
830        pcre_dfa_exec() could read past the end of the passed subject if there was
831        no match. To help with detecting such bugs (e.g. with valgrind), I modified
832        pcretest so that it places the subject at the end of its malloc-ed buffer.
833    
834    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
835        exec() might read past the end of the data buffer in UTF-8 mode.
836    
837    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
838        the data contained the byte 0x85 as part of a UTF-8 character within its
839        first line. This applied both to normal and DFA matching.
840    
841    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
842        /^[^d]*?$/8 failed to match "abc".
843    
844    16. Added a missing copyright notice to pcrecpp_internal.h.
845    
846    17. Make it more clear in the documentation that values returned from
847        pcre_exec() in ovector are byte offsets, not character counts.
848    
849    18. Tidied a few places to stop certain compilers from issuing warnings.
850    
851    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
852        supplied by Stefan Weber. I made a further small update for 7.8 because
853        there is a change of source arrangements: the pcre_searchfuncs.c module is
854        replaced by pcre_ucd.c.
855    
856    
857    Version 7.7 07-May-08
858    ---------------------
859    
860    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
861        a string to a long long, pretend we don't even have a long long." This is
862        done by checking for the strtoq, strtoll, and _strtoi64 functions.
863    
864    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
865        pre-7.6 versions, which defined a global no_arg variable instead of putting
866        it in the RE class. (See also #8 below.)
867    
868    3.  Remove a line of dead code, identified by coverity and reported by Nuno
869        Lopes.
870    
871    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
872    
873        (1) The include/exclude patterns were being applied to the whole pathnames
874            of files, instead of just to the final components.
875    
876        (2) If there was more than one level of directory, the subdirectories were
877            skipped unless they satisfied the include/exclude conditions. This is
878            inconsistent with GNU grep (and could even be seen as contrary to the
879            pcregrep specification - which I improved to make it absolutely clear).
880            The action now is always to scan all levels of directory, and just
881            apply the include/exclude patterns to regular files.
882    
883    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
884        --exclude_dir in the tests to avoid scanning .svn directories.
885    
886    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
887        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
888        doesn't support NULs in patterns.
889    
890    7.  Added some missing "const"s to declarations of static tables in
891        pcre_compile.c and pcre_dfa_exec.c.
892    
893    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
894        caused by fix #2  above. (Subsequently also a second patch to fix the
895        first patch. And a third patch - this was a messy problem.)
896    
897    9.  Applied Craig's patch to remove the use of push_back().
898    
899    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
900        matching function regexec().
901    
902    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
903        which, however, unlike Perl's \g{...}, are subroutine calls, not back
904        references. PCRE supports relative numbers with this syntax (I don't think
905        Oniguruma does).
906    
907    12. Previously, a group with a zero repeat such as (...){0} was completely
908        omitted from the compiled regex. However, this means that if the group
909        was called as a subroutine from elsewhere in the pattern, things went wrong
910        (an internal error was given). Such groups are now left in the compiled
911        pattern, with a new opcode that causes them to be skipped at execution
912        time.
913    
914    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
915        to the way PCRE behaves:
916    
917        (a) A lone ] character is dis-allowed (Perl treats it as data).
918    
919        (b) A back reference to an unmatched subpattern matches an empty string
920            (Perl fails the current match path).
921    
922        (c) A data ] in a character class must be notated as \] because if the
923            first data character in a class is ], it defines an empty class. (In
924            Perl it is not possible to have an empty class.) The empty class []
925            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
926            The negative empty class [^] matches any one character, independently
927            of the DOTALL setting.
928    
929    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
930        non-existent subpattern following a character class starting with ']' and
931        containing () gave an internal compiling error instead of "reference to
932        non-existent subpattern". Fortunately, when the pattern did exist, the
933        compiled code was correct. (When scanning forwards to check for the
934        existencd of the subpattern, it was treating the data ']' as terminating
935        the class, so got the count wrong. When actually compiling, the reference
936        was subsequently set up correctly.)
937    
938    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
939        it was being rejected as not supported by pcre_dfa_exec(), even though
940        other assertions are supported. I have made pcre_dfa_exec() support
941        (*FAIL).
942    
943    16. The implementation of 13c above involved the invention of a new opcode,
944        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
945        cannot be changed at match time, I realized I could make a small
946        improvement to matching performance by compiling OP_ALLANY instead of
947        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
948        on the OP_ANY path.
949    
950    17. Compiling pcretest on Windows with readline support failed without the
951        following two fixes: (1) Make the unistd.h include conditional on
952        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
953    
954    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
955        ncurses library to be included for pcretest when ReadLine support is
956        requested, but also to allow for it to be overridden. This patch came from
957        Daniel Bergström.
958    
959    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
960        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
961        any errors with the current Unicode tables. Thanks to Peter Kankowski for
962        spotting this.
963    
964    
965    Version 7.6 28-Jan-08
966    ---------------------
967    
968    1.  A character class containing a very large number of characters with
969        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
970        overflow.
971    
972    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
973        HAVE_LONG_LONG is not defined.
974    
975    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
976        bring them up to date and include new features. This patch includes:
977    
978        - Fixed PH's badly added libz and libbz2 support.
979        - Fixed a problem with static linking.
980        - Added pcredemo. [But later removed - see 7 below.]
981        - Fixed dftables problem and added an option.
982        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
983            HAVE_LONG_LONG.
984        - Added readline support for pcretest.
985        - Added an listing of the option settings after cmake has run.
986    
987    4.  A user submitted a patch to Makefile that makes it easy to create
988        "pcre.dll" under mingw when using Configure/Make. I added stuff to
989        Makefile.am that cause it to include this special target, without
990        affecting anything else. Note that the same mingw target plus all
991        the other distribution libraries and programs are now supported
992        when configuring with CMake (see 6 below) instead of with
993        Configure/Make.
994    
995    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
996        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
997        exported in the Windows port". It has not yet been confirmed that the patch
998        solves the problem, but it does no harm.
999    
1000    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1001        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1002        with CMake, and also correct the comment about stack recursion.
1003    
1004    7.  Remove the automatic building of pcredemo from the ./configure system and
1005        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1006        of a program that users should build themselves after PCRE is installed, so
1007        building it automatically is not really right. What is more, it gave
1008        trouble in some build environments.
1009    
1010    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1011    
1012    
1013    Version 7.5 10-Jan-08
1014    ---------------------
1015    
1016    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1017        values in parens when parsing an RE using the C++ wrapper."
1018    
1019    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1020        Characters greater than 255 were excluded from the class instead of being
1021        included.
1022    
1023    3.  The same bug as (2) above applied to negated POSIX classes such as
1024        [:^space:].
1025    
1026    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1027        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1028        I have changed it.
1029    
1030    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1031        first named subpattern) and a construct such as (?&a) would reference the
1032        first named subpattern whose name started with "a" (in other words, the
1033        length check was missing). Both these problems are fixed. "Subpattern name
1034        expected" is now given for (?&) (a zero-length name), and this patch also
1035        makes it give the same error for \k'' (previously it complained that that
1036        was a reference to a non-existent subpattern).
1037    
1038    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1039        this is right because (?- can be followed by option settings as well as by
1040        digits. I have, however, made the messages clearer.
1041    
1042    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1043        than the number used in the conditional) now cause a compile-time error.
1044        This is actually not compatible with Perl, which accepts such patterns, but
1045        treats the conditional as always being FALSE (as PCRE used to), but it
1046        seems to me that giving a diagnostic is better.
1047    
1048    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1049        and messages.
1050    
1051    9.  Fix two occurrences of "backslash" in comments that should have been
1052        "backspace".
1053    
1054    10. Remove two redundant lines of code that can never be obeyed (their function
1055        was moved elsewhere).
1056    
1057    11. The program that makes PCRE's Unicode character property table had a bug
1058        which caused it to generate incorrect table entries for sequences of
1059        characters that have the same character type, but are in different scripts.
1060        It amalgamated them into a single range, with the script of the first of
1061        them. In other words, some characters were in the wrong script. There were
1062        thirteen such cases, affecting characters in the following ranges:
1063    
1064          U+002b0 - U+002c1
1065          U+0060c - U+0060d
1066          U+0061e - U+00612
1067          U+0064b - U+0065e
1068          U+0074d - U+0076d
1069          U+01800 - U+01805
1070          U+01d00 - U+01d77
1071          U+01d9b - U+01dbf
1072          U+0200b - U+0200f
1073          U+030fc - U+030fe
1074          U+03260 - U+0327f
1075          U+0fb46 - U+0fbb1
1076          U+10450 - U+1049d
1077    
1078    12. The -o option (show only the matching part of a line) for pcregrep was not
1079        compatible with GNU grep in that, if there was more than one match in a
1080        line, it showed only the first of them. It now behaves in the same way as
1081        GNU grep.
1082    
1083    13. If the -o and -v options were combined for pcregrep, it printed a blank
1084        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1085        does the same. The return code can be used to tell if there were any
1086        non-matching lines.
1087    
1088    14. Added --file-offsets and --line-offsets to pcregrep.
1089    
1090    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1091        infinitely looping recursion. The bug was that positive lookaheads were not
1092        being skipped when checking for a possible empty match (negative lookaheads
1093        and both kinds of lookbehind were skipped).
1094    
1095    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1096        inclusion of <windows.h> to before rather than after the definition of
1097        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1098    
1099    17. Specifying a possessive quantifier with a specific limit for a Unicode
1100        character property caused pcre_compile() to compile bad code, which led at
1101        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1102        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1103        caused the error; without that there was no problem.
1104    
1105    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1106    
1107    19. Added --enable-pcretest-libreadline.
1108    
1109    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1110        RE::GlobalReplace(). As a result, the number of replacements returned was
1111        double what it should be. I removed one of the increments, but Craig sent a
1112        later patch that removed the other one (the right fix) and added unit tests
1113        that check the return values (which was not done before).
1114    
1115    21. Several CMake things:
1116    
1117        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1118            the names libpcre and libpcreposix, not just pcre and pcreposix.
1119    
1120        (2) The above change means that pcretest and pcregrep are now correctly
1121            linked with the newly-built libraries, not previously installed ones.
1122    
1123        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1124    
1125    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1126        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1127        UTF-8 newline character). The key issue is that the pattern starts .*;
1128        this means that the match must be either at the beginning, or after a
1129        newline. The bug was in the code for advancing after a failed match and
1130        checking that the new position followed a newline. It was not taking
1131        account of UTF-8 characters correctly.
1132    
1133    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1134        character classes. PCRE was not treating the sequence [:...:] as a
1135        character class unless the ... were all letters. Perl, however, seems to
1136        allow any characters between [: and :], though of course it rejects as
1137        unknown any "names" that contain non-letters, because all the known class
1138        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1139        for example, whereas PCRE did not - it did not recognize a POSIX character
1140        class. This seemed a bit dangerous, so the code has been changed to be
1141        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1142        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1143        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1144        Perl does, and where it didn't before.
1145    
1146    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1147        Windows environments %n is disabled by default.
1148    
1149    
1150    Version 7.4 21-Sep-07
1151    ---------------------
1152    
1153    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1154        means that a class such as [\s] counted as "explicit reference to CR or
1155        LF". That isn't really right - the whole point of the change was to try to
1156        help when there was an actual mention of one of the two characters. So now
1157        the change happens only if \r or \n (or a literal CR or LF) character is
1158        encountered.
1159    
1160    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1161        of both had grown to the point where there were only 3 bits left.
1162        Fortunately, there was spare space in the data structure, and so I have
1163        moved the internal flags into a new 16-bit field to free up more option
1164        bits.
1165    
1166    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1167        but did not set the internal JCHANGED flag - either of these is enough to
1168        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1169        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1170        start sets both bits.
1171    
1172    4.  Added options (at build time, compile time, exec time) to change \R from
1173        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1174    
1175    5.  doc/pcresyntax.html was missing from the distribution.
1176    
1177    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1178        compatibility, even though it is no longer used.
1179    
1180    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1181        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1182        windows.h file is present (where different names are used). [This was
1183        reversed later after testing - see 16 below.]
1184    
1185    8.  Changed all #include <config.h> to #include "config.h". There were also
1186        some further <pcre.h> cases that I changed to "pcre.h".
1187    
1188    9.  When pcregrep was used with the --colour option, it missed the line ending
1189        sequence off the lines that it output.
1190    
1191    10. It was pointed out to me that arrays of string pointers cause lots of
1192        relocations when a shared library is dynamically loaded. A technique of
1193        using a single long string with a table of offsets can drastically reduce
1194        these. I have refactored PCRE in four places to do this. The result is
1195        dramatic:
1196    
1197          Originally:                          290
1198          After changing UCP table:            187
1199          After changing error message table:   43
1200          After changing table of "verbs"       36
1201          After changing table of Posix names   22
1202    
1203        Thanks to the folks working on Gregex for glib for this insight.
1204    
1205    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1206        unicode-properties was also set.
1207    
1208    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1209    
1210    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1211        checked only for CRLF.
1212    
1213    14. Added casts to pcretest.c to avoid compiler warnings.
1214    
1215    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1216    
1217    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1218        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1219        entirely. This removes changes made in 7 above.
1220    
1221    17. The CMake files have been updated, and there is now more information about
1222        building with CMake in the NON-UNIX-USE document.
1223    
1224    
1225    Version 7.3 28-Aug-07
1226    ---------------------
1227    
1228     1. In the rejigging of the build system that eventually resulted in 7.1, the
1229        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1230        brackets there is not right, since it causes compilers to look for an
1231        installed pcre.h, not the version that is in the source that is being
1232        compiled (which of course may be different). I have changed it back to:
1233    
1234          #include "pcre.h"
1235    
1236        I have a vague recollection that the change was concerned with compiling in
1237        different directories, but in the new build system, that is taken care of
1238        by the VPATH setting the Makefile.
1239    
1240     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1241        when the subject happened to end in the byte 0x85 (e.g. if the last
1242        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1243        characters but of course it shouldn't be taken as a newline when it is part
1244        of another character. The bug was that, for an unlimited repeat of . in
1245        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1246        characters when looking for a newline.
1247    
1248     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1249    
1250     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1251        in debug output.
1252    
1253     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1254        long printing in the pcrecpp unittest when running under MinGW.
1255    
1256     6. ESC_K was left out of the EBCDIC table.
1257    
1258     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1259        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1260        limit also applies to "virtual nesting" when a pattern is recursive, and in
1261        this case 1000 isn't so big. I have been able to remove this limit at the
1262        expense of backing off one optimization in certain circumstances. Normally,
1263        when pcre_exec() would call its internal match() function recursively and
1264        immediately return the result unconditionally, it uses a "tail recursion"
1265        feature to save stack. However, when a subpattern that can match an empty
1266        string has an unlimited repetition quantifier, it no longer makes this
1267        optimization. That gives it a stack frame in which to save the data for
1268        checking that an empty string has been matched. Previously this was taken
1269        from the 1000-entry workspace that had been reserved. So now there is no
1270        explicit limit, but more stack is used.
1271    
1272     8. Applied Daniel's patches to solve problems with the import/export magic
1273        syntax that is required for Windows, and which was going wrong for the
1274        pcreposix and pcrecpp parts of the library. These were overlooked when this
1275        problem was solved for the main library.
1276    
1277     9. There were some crude static tests to avoid integer overflow when computing
1278        the size of patterns that contain repeated groups with explicit upper
1279        limits. As the maximum quantifier is 65535, the maximum group length was
1280        set at 30,000 so that the product of these two numbers did not overflow a
1281        32-bit integer. However, it turns out that people want to use groups that
1282        are longer than 30,000 bytes (though not repeat them that many times).
1283        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1284        made it possible to implement the integer overflow checks in a much more
1285        dynamic way, which I have now done. The artificial limitation on group
1286        length has been removed - we now have only the limit on the total length of
1287        the compiled pattern, which depends on the LINK_SIZE setting.
1288    
1289    10. Fixed a bug in the documentation for get/copy named substring when
1290        duplicate names are permitted. If none of the named substrings are set, the
1291        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1292        empty string.
1293    
1294    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1295        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1296        because the ] is interpreted as the first data character and the
1297        terminating ] is not found. PCRE has been made compatible with Perl in this
1298        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1299        cause memory overwriting.
1300    
1301    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1302        string has been matched (to stop an infinite loop). It was not recognizing
1303        a conditional subpattern that could match an empty string if that
1304        subpattern was within another subpattern. For example, it looped when
1305        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1306        condition was not nested. This bug has been fixed.
1307    
1308    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1309        past the start of the subject in the presence of bytes with the top bit
1310        set, for example "\x8aBCD".
1311    
1312    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1313        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1314    
1315    14. Optimized (?!) to (*FAIL).
1316    
1317    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1318        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1319        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1320        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1321        does: it's just the validity check that is more restrictive.
1322    
1323    16. Inserted checks for integer overflows during escape sequence (backslash)
1324        processing, and also fixed erroneous offset values for syntax errors during
1325        backslash processing.
1326    
1327    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1328        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1329    
1330    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1331        caused an overrun.
1332    
1333    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1334        something other than just ASCII characters) inside a group that had an
1335        unlimited repeat caused a loop at compile time (while checking to see
1336        whether the group could match an empty string).
1337    
1338    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1339        [\P{Any}] did so. (Error in the code for printing property names.)
1340    
1341    21. An orphan \E inside a character class could cause a crash.
1342    
1343    22. A repeated capturing bracket such as (A)? could cause a wild memory
1344        reference during compilation.
1345    
1346    23. There are several functions in pcre_compile() that scan along a compiled
1347        expression for various reasons (e.g. to see if it's fixed length for look
1348        behind). There were bugs in these functions when a repeated \p or \P was
1349        present in the pattern. These operators have additional parameters compared
1350        with \d, etc, and these were not being taken into account when moving along
1351        the compiled data. Specifically:
1352    
1353        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1354            length.
1355    
1356        (b) An item such as \pL+ within a repeated group could cause crashes or
1357            loops.
1358    
1359        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1360            "reference to non-existent subpattern" error.
1361    
1362        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1363    
1364    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1365        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1366    
1367    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1368    
1369    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1370        character were causing crashes (broken optimization).
1371    
1372    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1373        \p or \P) caused a compile-time loop.
1374    
1375    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1376        break. For example, the unstudied pattern [\r\n]A does not match the string
1377        "\r\nA" because change 7.0/46 below moves the current point on by two
1378        characters after failing to match at the start. However, the pattern \nA
1379        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1380        the same is true. There doesn't seem any very clean way out of this, but
1381        what I have chosen to do makes the common cases work: PCRE now takes note
1382        of whether there can be an explicit match for \r or \n anywhere in the
1383        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1384        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1385        pattern has explicit CR or LF references.
1386    
1387    29. Added (*CR) etc for changing newline setting at start of pattern.
1388    
1389    
1390    Version 7.2 19-Jun-07
1391    ---------------------
1392    
1393     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1394        which is apparently normally available under Windows.
1395    
1396     2. Re-jig the pcregrep tests with different newline settings in an attempt
1397        to make them independent of the local environment's newline setting.
1398    
1399     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1400    
1401     4. Some of the "internals" tests were previously cut out when the link size
1402        was not 2, because the output contained actual offsets. The recent new
1403        "Z" feature of pcretest means that these can be cut out, making the tests
1404        usable with all link sizes.
1405    
1406     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1407        stack recursion. This gives a massive performance boost under BSD, but just
1408        a small improvement under Linux. However, it saves one field in the frame
1409        in all cases.
1410    
1411     6. Added more features from the forthcoming Perl 5.10:
1412    
1413        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1414            recursion call. It refers to the nth most recently opened parentheses.
1415    
1416        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1417            to be opened parentheses.
1418    
1419        (c) Conditions that refer to capturing parentheses can be specified
1420            relatively, for example, (?(-2)... or (?(+3)...
1421    
1422        (d) \K resets the start of the current match so that everything before
1423            is not part of it.
1424    
1425        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1426    
1427        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1428            reference syntax.
1429    
1430        (g) (?| introduces a group in which the numbering of parentheses in each
1431            alternative starts with the same number.
1432    
1433        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1434    
1435     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1436        PCRE_INFO_JCHANGED.
1437    
1438     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1439        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1440        for detecting groups that can match an empty string.
1441    
1442     9. A pattern with a very large number of alternatives (more than several
1443        hundred) was running out of internal workspace during the pre-compile
1444        phase, where pcre_compile() figures out how much memory will be needed. A
1445        bit of new cunning has reduced the workspace needed for groups with
1446        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1447        workspace instead of running out of the 4096 that are available.
1448    
1449    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1450    
1451    11. Applied patch from Google to remove an optimization that didn't quite work.
1452        The report of the bug said:
1453    
1454          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1455          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1456          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1457    
1458    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1459        it matched the wrong number of bytes.
1460    
1461    
1462    Version 7.1 24-Apr-07
1463    ---------------------
1464    
1465     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1466        that is more "standard", making use of automake and other Autotools. There
1467        is some re-arrangement of the files and adjustment of comments consequent
1468        on this.
1469    
1470     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1471        for recursive directory scanning broke on some systems because the files
1472        are not scanned in any specific order and on different systems the order
1473        was different. A call to "sort" has been inserted into RunGrepTest for the
1474        approprate test as a short-term fix. In the longer term there may be an
1475        alternative.
1476    
1477     3. I had an email from Eric Raymond about problems translating some of PCRE's
1478        man pages to HTML (despite the fact that I distribute HTML pages, some
1479        people do their own conversions for various reasons). The problems
1480        concerned the use of low-level troff macros .br and .in. I have therefore
1481        removed all such uses from the man pages (some were redundant, some could
1482        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1483        HTML has been updated to handle .nf/.fi and to complain if it encounters
1484        .br or .in.
1485    
1486     4. Updated comments in configure.ac that get placed in config.h.in and also
1487        arranged for config.h to be included in the distribution, with the name
1488        config.h.generic, for the benefit of those who have to compile without
1489        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1490    
1491     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1492        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1493        makevp.bat for the current PCRE, using the additional files
1494        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1495    
1496     6. A Windows user reported a minor discrepancy with test 2, which turned out
1497        to be caused by a trailing space on an input line that had got lost in his
1498        copy. The trailing space was an accident, so I've just removed it.
1499    
1500     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1501        that is needed.
1502    
1503     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1504        as "const" (a) because they are and (b) because it helps the PHP
1505        maintainers who have recently made a script to detect big data structures
1506        in the php code that should be moved to the .rodata section. I remembered
1507        to update Builducptable as well, so it won't revert if ucptable.h is ever
1508        re-created.
1509    
1510     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1511        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1512        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1513        support is not required. This saves 1.5-2K of code, which is important in
1514        some applications.
1515    
1516        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1517        so as not to refer to the tables, even though these functions will never be
1518        called when UTF-8 support is disabled. Otherwise there are problems with a
1519        shared library.
1520    
1521    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1522    
1523        (a) It was defining its arguments as char * instead of void *.
1524    
1525        (b) It was assuming that all moves were upwards in memory; this was true
1526            a long time ago when I wrote it, but is no longer the case.
1527    
1528        The emulated memove() is provided for those environments that have neither
1529        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1530        is clearly not the case, as these two bugs were recently reported.
1531    
1532    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1533        and Detrail to create the HTML documentation, the .txt form of the man
1534        pages, and it removes trailing spaces from listed files. It also creates
1535        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1536        case, it wraps all the #defines with #ifndefs. This script should be run
1537        before "make dist".
1538    
1539    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1540        with Unicode property support.
1541    
1542        (a) For a maximizing quantifier, if the two different cases of the
1543            character were of different lengths in their UTF-8 codings (there are
1544            some cases like this - I found 11), and the matching function had to
1545            back up over a mixture of the two cases, it incorrectly assumed they
1546            were both the same length.
1547    
1548        (b) When PCRE was configured to use the heap rather than the stack for
1549            recursion during matching, it was not correctly preserving the data for
1550            the other case of a UTF-8 character when checking ahead for a match
1551            while processing a minimizing repeat. If the check also involved
1552            matching a wide character, but failed, corruption could cause an
1553            erroneous result when trying to check for a repeat of the original
1554            character.
1555    
1556    13. Some tidying changes to the testing mechanism:
1557    
1558        (a) The RunTest script now detects the internal link size and whether there
1559            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1560            values substituted by "configure". (The RunGrepTest script already did
1561            this for UTF-8.) The configure.ac script no longer substitutes the
1562            relevant variables.
1563    
1564        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1565            with length and offset values. This means that the output is different
1566            for different internal link sizes. Test 2 is skipped for link sizes
1567            other than 2 because of this, bypassing the problem. Unfortunately,
1568            there was also a test in test 3 (the locale tests) that used /B and
1569            failed for link sizes other than 2. Rather than cut the whole test out,
1570            I have added a new /Z option to pcretest that replaces the length and
1571            offset values with spaces. This is now used to make test 3 independent
1572            of link size. (Test 2 will be tidied up later.)
1573    
1574    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1575        segmentation fault instead of returning the appropriate error message.
1576    
1577    15. In multiline mode when the newline sequence was set to "any", the pattern
1578        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1579        This doesn't seem right; it now treats the CRLF combination as the line
1580        ending, and so does not match in that case. It's only a pattern such as ^$
1581        that would hit this one: something like ^ABC$ would have failed after \r
1582        and then tried again after \r\n.
1583    
1584    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1585        in an attempt to make files that differ only in their line terminators
1586        compare equal. This works on Linux.
1587    
1588    17. Under certain error circumstances pcregrep might try to free random memory
1589        as it exited. This is now fixed, thanks to valgrind.
1590    
1591    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1592        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1593        was because its rules for how to advance for /g after matching an empty
1594        string at the end of a line did not allow for this case. They now check for
1595        it specially.
1596    
1597    20. pcretest is supposed to handle patterns and data of any length, by
1598        extending its buffers when necessary. It was getting this wrong when the
1599        buffer for a data line had to be extended.
1600    
1601    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1602        CRLF as a newline sequence.
1603    
1604    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1605        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1606        I have nevertheless tidied it up.
1607    
1608    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1609    
1610    24. Added a man page for pcre-config.
1611    
1612    
1613    Version 7.0 19-Dec-06
1614    ---------------------
1615    
1616     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1617        moving to gcc 4.1.1.
1618    
1619     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1620        sys/time.h, which is documented as needed for this function. It doesn't
1621        seem to matter on Linux, but it showed up on some releases of OS X.
1622    
1623     3. It seems that there are systems where bytes whose values are greater than
1624        127 match isprint() in the "C" locale. The "C" locale should be the
1625        default when a C program starts up. In most systems, only ASCII printing
1626        characters match isprint(). This difference caused the output from pcretest
1627        to vary, making some of the tests fail. I have changed pcretest so that:
1628    
1629        (a) When it is outputting text in the compiled version of a pattern, bytes
1630            other than 32-126 are always shown as hex escapes.
1631    
1632        (b) When it is outputting text that is a matched part of a subject string,
1633            it does the same, unless a different locale has been set for the match
1634            (using the /L modifier). In this case, it uses isprint() to decide.
1635    
1636     4. Fixed a major bug that caused incorrect computation of the amount of memory
1637        required for a compiled pattern when options that changed within the
1638        pattern affected the logic of the preliminary scan that determines the
1639        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1640        that the computed length was too small. The symptoms of this bug were
1641        either the PCRE error "internal error: code overflow" from pcre_compile(),
1642        or a glibc crash with a message such as "pcretest: free(): invalid next
1643        size (fast)". Examples of patterns that provoked this bug (shown in
1644        pcretest format) are:
1645    
1646          /(?-x: )/x
1647          /(?x)(?-x: \s*#\s*)/
1648          /((?i)[\x{c0}])/8
1649          /(?i:[\x{c0}])/8
1650    
1651        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1652        is now done differently.
1653    
1654     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1655        wrapper classes; (b) implement a new function in the C++ scanner that is
1656        more efficient than the old way of doing things because it avoids levels of
1657        recursion in the regex matching; (c) add a paragraph to the documentation
1658        for the FullMatch() function.
1659    
1660     6. The escape sequence \n was being treated as whatever was defined as
1661        "newline". Not only was this contrary to the documentation, which states
1662        that \n is character 10 (hex 0A), but it also went horribly wrong when
1663        "newline" was defined as CRLF. This has been fixed.
1664    
1665     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1666        was being set to -1 for the "end of line" case (supposedly a value that no
1667        character can have). Though this value is never used (the check for end of
1668        line is "zero bytes in current character"), it caused compiler complaints.
1669        I've changed it to 0xffffffff.
1670    
1671     8. In pcre_version.c, the version string was being built by a sequence of
1672        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1673        string (as it is for production releases) called a macro with an empty
1674        argument. The C standard says the result of this is undefined. The gcc
1675        compiler treats it as an empty string (which was what was wanted) but it is
1676        reported that Visual C gives an error. The source has been hacked around to
1677        avoid this problem.
1678    
1679     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1680        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1681        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1682        of them did).
1683    
1684    10. Originally, pcretest opened its input and output without "b"; then I was
1685        told that "b" was needed in some environments, so it was added for release
1686        5.0 to both the input and output. (It makes no difference on Unix-like
1687        systems.) Later I was told that it is wrong for the input on Windows. I've
1688        now abstracted the modes into two macros, to make it easier to fiddle with
1689        them, and removed "b" from the input mode under Windows.
1690    
1691    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1692    
1693    12. Added -help and --help to pcretest as an official way of being reminded
1694        of the options.
1695    
1696    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1697        and pcrecpp.cc because they annoy compilers at high warning levels.
1698    
1699    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1700    
1701    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1702        scripts are not C programs :-) and which was not noticed because it works
1703        on Linux.
1704    
1705    16. pcretest is supposed to handle any length of pattern and data line (as one
1706        line or as a continued sequence of lines) by extending its input buffer if
1707        necessary. This feature was broken for very long pattern lines, leading to
1708        a string of junk being passed to pcre_compile() if the pattern was longer
1709        than about 50K.
1710    
1711    17. I have done a major re-factoring of the way pcre_compile() computes the
1712        amount of memory needed for a compiled pattern. Previously, there was code
1713        that made a preliminary scan of the pattern in order to do this. That was
1714        OK when PCRE was new, but as the facilities have expanded, it has become
1715        harder and harder to keep it in step with the real compile phase, and there
1716        have been a number of bugs (see for example, 4 above). I have now found a
1717        cunning way of running the real compile function in a "fake" mode that
1718        enables it to compute how much memory it would need, while actually only
1719        ever using a few hundred bytes of working memory and without too many
1720        tests of the mode. This should make future maintenance and development
1721        easier. A side effect of this work is that the limit of 200 on the nesting
1722        depth of parentheses has been removed (though this was never a serious
1723        limitation, I suspect). However, there is a downside: pcre_compile() now
1724        runs more slowly than before (30% or more, depending on the pattern). I
1725        hope this isn't a big issue. There is no effect on runtime performance.
1726    
1727    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1728        newline (only possible for the last line of a file) and it was a
1729        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1730    
1731    19. Added additional timing features to pcretest. (1) The -tm option now times
1732        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1733        separate command line item, by a number that specifies the number of
1734        repeats to use when timing. The default is 50000; this gives better
1735        precision, but takes uncomfortably long for very large patterns.
1736    
1737    20. Extended pcre_study() to be more clever in cases where a branch of a
1738        subpattern has no definite first character. For example, (a*|b*)[cd] would
1739        previously give no result from pcre_study(). Now it recognizes that the
1740        first character must be a, b, c, or d.
1741    
1742    21. There was an incorrect error "recursive call could loop indefinitely" if
1743        a subpattern (or the entire pattern) that was being tested for matching an
1744        empty string contained only one non-empty item after a nested subpattern.
1745        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1746        incorrectly, because the \d was being skipped in the check.
1747    
1748    22. The pcretest program now has a new pattern option /B and a command line
1749        option -b, which is equivalent to adding /B to every pattern. This causes
1750        it to show the compiled bytecode, without the additional information that
1751        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1752        is the same as /B/I).
1753    
1754    23. A new optimization is now able automatically to treat some sequences such
1755        as a*b as a*+b. More specifically, if something simple (such as a character
1756        or a simple class like \d) has an unlimited quantifier, and is followed by
1757        something that cannot possibly match the quantified thing, the quantifier
1758        is automatically "possessified".
1759    
1760    24. A recursive reference to a subpattern whose number was greater than 39
1761        went wrong under certain circumstances in UTF-8 mode. This bug could also
1762        have affected the operation of pcre_study().
1763    
1764    25. Realized that a little bit of performance could be had by replacing
1765        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1766    
1767    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1768    
1769    27. Possessive quantifiers such as a++ were previously implemented by turning
1770        them into atomic groups such as ($>a+). Now they have their own opcodes,
1771        which improves performance. This includes the automatically created ones
1772        from 23 above.
1773    
1774    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1775        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1776        the first matched character to be a colon. This applied both to named and
1777        numbered groups.
1778    
1779    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1780    
1781    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1782        building PCRE on Windows easier, so I have included it in the distribution.
1783    
1784    31. There is now a check in pcretest against a ridiculously large number being
1785        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1786        loop, the loop is abandoned.
1787    
1788    32. Forward references to subpatterns in conditions such as (?(2)...) where
1789        subpattern 2 is defined later cause pcre_compile() to search forwards in
1790        the pattern for the relevant set of parentheses. This search went wrong
1791        when there were unescaped parentheses in a character class, parentheses
1792        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1793    
1794    33. "Subroutine" calls and backreferences were previously restricted to
1795        referencing subpatterns earlier in the regex. This restriction has now
1796        been removed.
1797    
1798    34. Added a number of extra features that are going to be in Perl 5.10. On the
1799        whole, these are just syntactic alternatives for features that PCRE had
1800        previously implemented using the Python syntax or my own invention. The
1801        other formats are all retained for compatibility.
1802    
1803        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1804            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1805            also .NET compatible.
1806    
1807        (b) A recursion or subroutine call to a named group can now be defined as
1808            (?&name) as well as (?P>name).
1809    
1810        (c) A backreference to a named group can now be defined as \k<name> or
1811            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1812            5.10, are also .NET compatible.
1813    
1814        (d) A conditional reference to a named group can now use the syntax
1815            (?(<name>) or (?('name') as well as (?(name).
1816    
1817        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1818            groups (named and numbered) that are never evaluated inline, but can be
1819            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1820            is always false. There may be only one alternative in such a group.
1821    
1822        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1823            as the simple (?(R). The condition is true only if the most recent
1824            recursion is that of the given number or name. It does not search out
1825            through the entire recursion stack.
1826    
1827        (g) The escape \gN or \g{N} has been added, where N is a positive or
1828            negative number, specifying an absolute or relative reference.
1829    
1830    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1831        some "unreachable code" warnings.
1832    
1833    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1834        things, this adds five new scripts.
1835    
1836    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1837        There were also incompatibilities regarding the handling of \Q..\E inside
1838        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1839        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1840    
1841    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1842        matches an empty string, and forcibly breaks the loop. There were bugs in
1843        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1844        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1845        separate and independent bugs (that affected different cases) have been
1846        fixed.
1847    
1848    39. Refactored the code to abolish the use of different opcodes for small
1849        capturing bracket numbers. This is a tidy that I avoided doing when I
1850        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1851        The new approach is not only tidier, it makes it possible to reduce the
1852        memory needed to fix the previous bug (38).
1853    
1854    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1855        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1856        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1857        mode.
1858    
1859    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1860        report.
1861    
1862    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1863        copy construction and assignment in the C++ wrapper.
1864    
1865    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1866        couple of bugs that could have given wrong results in the "--newline=crlf"
1867        case.
1868    
1869    44. Added a number of casts and did some reorganization of signed/unsigned int
1870        variables following suggestions from Dair Grant. Also renamed the variable
1871        "this" as "item" because it is a C++ keyword.
1872    
1873    45. Arranged for dftables to add
1874    
1875          #include "pcre_internal.h"
1876    
1877        to pcre_chartables.c because without it, gcc 4.x may remove the array
1878        definition from the final binary if PCRE is built into a static library and
1879        dead code stripping is activated.
1880    
1881    46. For an unanchored pattern, if a match attempt fails at the start of a
1882        newline sequence, and the newline setting is CRLF or ANY, and the next two
1883        characters are CRLF, advance by two characters instead of one.
1884    
1885    
1886    Version 6.7 04-Jul-06
1887    ---------------------
1888    
1889     1. In order to handle tests when input lines are enormously long, pcretest has
1890        been re-factored so that it automatically extends its buffers when
1891        necessary. The code is crude, but this _is_ just a test program. The
1892        default size has been increased from 32K to 50K.
1893    
1894     2. The code in pcre_study() was using the value of the re argument before
1895        testing it for NULL. (Of course, in any sensible call of the function, it
1896        won't be NULL.)
1897    
1898     3. The memmove() emulation function in pcre_internal.h, which is used on
1899        systems that lack both memmove() and bcopy() - that is, hardly ever -
1900        was missing a "static" storage class specifier.
1901    
1902     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1903        containing an extended class (one that cannot be represented by a bitmap
1904        because it contains high-valued characters or Unicode property items, e.g.
1905        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1906        pattern, but PCRE should not loop if you do not (it no longer does).
1907        [Detail: two cases were found: (a) a repeated subpattern containing an
1908        extended class; (b) a recursive reference to a subpattern that followed a
1909        previous extended class. It wasn't skipping over the extended class
1910        correctly when UTF-8 mode was not set.]
1911    
1912     5. A negated single-character class was not being recognized as fixed-length
1913        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1914        compile error "lookbehind assertion is not fixed length".
1915    
1916     6. The RunPerlTest auxiliary script was showing an unexpected difference
1917        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1918        write a Perl script that can interpret lines of an input file either as
1919        byte characters or as UTF-8, which is what "perltest" was being required to
1920        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1921        can't do is switch easily at run time between having the "use utf8;" pragma
1922        or not. In the end, I fudged it by using the RunPerlTest script to insert
1923        "use utf8;" explicitly for the UTF-8 tests.
1924    
1925     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1926        the end of the subject string, contrary to the documentation and to what
1927        Perl does. This was true of both matching functions. Now it matches only at
1928        the start of the subject and immediately after *internal* newlines.
1929    
1930     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1931        a pointer to an int instead of a pointer to an unsigned long int. This
1932        caused problems on 64-bit systems.
1933    
1934     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1935        instance of the 'standard' template library not being so standard".
1936    
1937    10. There was no check on the number of named subpatterns nor the maximum
1938        length of a subpattern name. The product of these values is used to compute
1939        the size of the memory block for a compiled pattern. By supplying a very
1940        long subpattern name and a large number of named subpatterns, the size
1941        computation could be caused to overflow. This is now prevented by limiting
1942        the length of names to 32 characters, and the number of named subpatterns
1943        to 10,000.
1944    
1945    11. Subpatterns that are repeated with specific counts have to be replicated in
1946        the compiled pattern. The size of memory for this was computed from the
1947        length of the subpattern and the repeat count. The latter is limited to
1948        65535, but there was no limit on the former, meaning that integer overflow
1949        could in principle occur. The compiled length of a repeated subpattern is
1950        now limited to 30,000 bytes in order to prevent this.
1951    
1952    12. Added the optional facility to have named substrings with the same name.
1953    
1954    13. Added the ability to use a named substring as a condition, using the
1955        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1956        are numbers (not recommended). Forward references are permitted.
1957    
1958    14. Added forward references in named backreferences (if you see what I mean).
1959    
1960    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1961        pattern could run off the end of the subject. For example, the pattern
1962        "(?s)(.{1,5})"8 did this with the subject "ab".
1963    
1964    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1965        PCRE_CASELESS was set when matching characters that were quantified with ?
1966        or *.
1967    
1968    17. A character class other than a single negated character that had a minimum
1969        but no maximum quantifier - for example [ab]{6,} - was not handled
1970        correctly by pce_dfa_exec(). It would match only one character.
1971    
1972    18. A valid (though odd) pattern that looked like a POSIX character
1973        class but used an invalid character after [ (for example [[,abc,]]) caused
1974        pcre_compile() to give the error "Failed: internal error: code overflow" or
1975        in some cases to crash with a glibc free() error. This could even happen if
1976        the pattern terminated after [[ but there just happened to be a sequence of
1977        letters, a binary zero, and a closing ] in the memory that followed.
1978    
1979    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1980        over the years. Originally (before any Unicode support), just the bottom 8
1981        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1982        output from "man perlunicode" includes this:
1983    
1984          The regular expression compiler produces polymorphic opcodes.  That
1985          is, the pattern adapts to the data and automatically switches to
1986          the Unicode character scheme when presented with Unicode data--or
1987          instead uses a traditional byte scheme when presented with byte
1988          data.
1989    
1990        Sadly, a wide octal escape does not cause a switch, and in a string with
1991        no other multibyte characters, these octal escapes are treated as before.
1992        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1993        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1994        Unicode string.
1995    
1996        I have not perpetrated such confusion in PCRE. Up till now, it took just
1997        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1998        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1999        translate to the appropriate multibyte character.
2000    
2001    29. Applied some refactoring to reduce the number of warnings from Microsoft
2002        and Borland compilers. This has included removing the fudge introduced
2003        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2004        a warning about an unused variable.
2005    
2006    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2007        characters since release 4.0, because Perl (from release 5.004) does not.
2008        [Or at least, is documented not to: some releases seem to be in conflict
2009        with the documentation.] However, when a pattern was studied with
2010        pcre_study() and all its branches started with \s, PCRE still included VT
2011        as a possible starting character. Of course, this did no harm; it just
2012        caused an unnecessary match attempt.
2013    
2014    22. Removed a now-redundant internal flag bit that recorded the fact that case
2015        dependency changed within the pattern. This was once needed for "required
2016        byte" processing, but is no longer used. This recovers a now-scarce options
2017        bit. Also moved the least significant internal flag bit to the most-
2018        significant bit of the word, which was not previously used (hangover from
2019        the days when it was an int rather than a uint) to free up another bit for
2020        the future.
2021    
2022    23. Added support for CRLF line endings as well as CR and LF. As well as the
2023        default being selectable at build time, it can now be changed at runtime
2024        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2025        specify that it is scanning data with non-default line endings.
2026    
2027    24. Changed the definition of CXXLINK to make it agree with the definition of
2028        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2029    
2030    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2031        recursions. This makes a big different to stack usage for some patterns.
2032    
2033    26. If a subpattern containing a named recursion or subroutine reference such
2034        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2035        the space required for the compiled pattern went wrong and gave too small a
2036        value. Depending on the environment, this could lead to "Failed: internal
2037        error: code overflow at offset 49" or "glibc detected double free or
2038        corruption" errors.
2039    
2040    27. Applied patches from Google (a) to support the new newline modes and (b) to
2041        advance over multibyte UTF-8 characters in GlobalReplace.
2042    
2043    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2044        difference for some implementation of PCRE in some Windows version.
2045    
2046    29. Added some extra testing facilities to pcretest:
2047    
2048        \q<number>   in a data line sets the "match limit" value
2049        \Q<number>   in a data line sets the "match recursion limt" value
2050        -S <number>  sets the stack size, where <number> is in megabytes
2051    
2052        The -S option isn't available for Windows.
2053    
2054    
2055  Version 6.6 06-Feb-06  Version 6.6 06-Feb-06
2056  ---------------------  ---------------------
2057    

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