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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    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
46    
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
55    
56    
57    Version 8.12 15-Jan-2011
58    ------------------------
59    
60    1.  Fixed some typos in the markup of the man pages, and wrote a script that
61        checks for such things as part of the documentation building process.
62    
63    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
64        --match-limit and --recursion-limit options (added for 8.11). In
65        particular, this made one of the standard tests fail. (The integer value
66        went into the wrong half of a long int.)
67    
68    3.  If the --colour option was given to pcregrep with -v (invert match), it
69        did strange things, either producing crazy output, or crashing. It should,
70        of course, ignore a request for colour when reporting lines that do not
71        match.
72    
73    4.  Another pcregrep bug caused similar problems if --colour was specified with
74        -M (multiline) and the pattern match finished with a line ending.
75    
76    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
77        matched in multiline mode, the following line was shown as part of the
78        match. This seems wrong, so I have changed it.
79    
80    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
81        the check for further matches in the same line (so they could be coloured)
82        to overrun the end of the current line. If another match was found, it was
83        incorrectly shown (and then shown again when found in the next line).
84    
85    7.  If pcregrep was compiled under Windows, there was a reference to the
86        function pcregrep_exit() before it was defined. I am assuming this was
87        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
88        reported by a user. I've moved the definition above the reference.
89    
90    
91    Version 8.11 10-Dec-2010
92    ------------------------
93    
94    1.  (*THEN) was not working properly if there were untried alternatives prior
95        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
96        backtracked to try for "b" instead of moving to the next alternative branch
97        at the same level (in this case, to look for "c"). The Perl documentation
98        is clear that when (*THEN) is backtracked onto, it goes to the "next
99        alternative in the innermost enclosing group".
100    
101    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
102        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
103        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
104        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
105        (*THEN).
106    
107    3.  If \s appeared in a character class, it removed the VT character from
108        the class, even if it had been included by some previous item, for example
109        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
110        of \s, but is part of the POSIX "space" class.)
111    
112    4.  A partial match never returns an empty string (because you can always
113        match an empty string at the end of the subject); however the checking for
114        an empty string was starting at the "start of match" point. This has been
115        changed to the "earliest inspected character" point, because the returned
116        data for a partial match starts at this character. This means that, for
117        example, /(?<=abc)def/ gives a partial match for the subject "abc"
118        (previously it gave "no match").
119    
120    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
121        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
122        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
123        has an implication that the given string is incomplete (because a partial
124        match is preferred over a full match). For this reason, these items now
125        give a partial match in this situation. [Aside: previously, the one case
126        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
127        match rather than a full match, which was wrong by the old rules, but is
128        now correct.]
129    
130    6.  There was a bug in the handling of #-introduced comments, recognized when
131        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
132        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
133        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
134        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
135        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
136        places in pcre_compile().
137    
138    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
139        comments when looking ahead for named forward references to subpatterns,
140        the only newline sequence it recognized was NL. It now handles newlines
141        according to the set newline convention.
142    
143    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
144        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
145        cater for a lack of strerror(). These oversights have been fixed.
146    
147    9.  Added --match-limit and --recursion-limit to pcregrep.
148    
149    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
150    
151    11. When the -o option was used, pcregrep was setting a return code of 1, even
152        when matches were found, and --line-buffered was not being honoured.
153    
154    12. Added an optional parentheses number to the -o and --only-matching options
155        of pcregrep.
156    
157    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
158        can match an empty string. The code to do it in pcretest and pcredemo
159        needed fixing:
160    
161        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
162            only one byte after an empty string match just before CRLF (this case
163            just got forgotten; "any" and "anycrlf" were OK).
164    
165        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
166            mode when an empty string match preceded an ASCII character followed by
167            a non-ASCII character. (The code for advancing by one character rather
168            than one byte was nonsense.)
169    
170        (c) The pcredemo.c sample program did not have any code at all to handle
171            the cases when CRLF is a valid newline sequence.
172    
173    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
174        as a starting offset was within the subject string. There is now a new
175        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
176        negative or greater than the length of the string. In order to test this,
177        pcretest is extended to allow the setting of negative starting offsets.
178    
179    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
180        starting offset points to the beginning of a UTF-8 character was
181        unnecessarily clumsy. I tidied it up.
182    
183    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
184        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
185    
186    17. Nobody had reported that the --include_dir option, which was added in
187        release 7.7 should have been called --include-dir (hyphen, not underscore)
188        for compatibility with GNU grep. I have changed it to --include-dir, but
189        left --include_dir as an undocumented synonym, and the same for
190        --exclude-dir, though that is not available in GNU grep, at least as of
191        release 2.5.4.
192    
193    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
194        characters from a string of bytes) have been redefined so as not to use
195        loops, in order to improve performance in some environments. At the same
196        time, I abstracted some of the common code into auxiliary macros to save
197        repetition (this should not affect the compiled code).
198    
199    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
200        compile-time error is now given if \c is not followed by an ASCII
201        character, that is, a byte less than 128. (In EBCDIC mode, the code is
202        different, and any byte value is allowed.)
203    
204    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
205        START_OPTIMIZE option, which is now allowed at compile time - but just
206        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
207        to pcregrep and other applications that have no direct access to PCRE
208        options. The new /Y option in pcretest sets this option when calling
209        pcre_compile().
210    
211    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
212        back references. Groups containing recursive back references were forced to
213        be atomic by that change, but in the case of named groups, the amount of
214        memory required was incorrectly computed, leading to "Failed: internal
215        error: code overflow". This has been fixed.
216    
217    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
218        pcretest.c, to avoid build problems in some Borland environments.
219    
220    
221    Version 8.10 25-Jun-2010
222    ------------------------
223    
224    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
225        THEN.
226    
227    2.  (*ACCEPT) was not working when inside an atomic group.
228    
229    3.  Inside a character class, \B is treated as a literal by default, but
230        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
231        causes the error). The code is unchanged, but I tidied the documentation.
232    
233    4.  Inside a character class, PCRE always treated \R and \X as literals,
234        whereas Perl faults them if its -w option is set. I have changed PCRE so
235        that it faults them when PCRE_EXTRA is set.
236    
237    5.  Added support for \N, which always matches any character other than
238        newline. (It is the same as "." when PCRE_DOTALL is not set.)
239    
240    6.  When compiling pcregrep with newer versions of gcc which may have
241        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
242        declared with attribute warn_unused_result" were given. Just casting the
243        result to (void) does not stop the warnings; a more elaborate fudge is
244        needed. I've used a macro to implement this.
245    
246    7.  Minor change to pcretest.c to avoid a compiler warning.
247    
248    8.  Added four artifical Unicode properties to help with an option to make
249        \s etc use properties (see next item). The new properties are: Xan
250        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
251    
252    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
253        use Unicode properties. (*UCP) at the start of a pattern can be used to set
254        this option. Modified pcretest to add /W to test this facility. Added
255        REG_UCP to make it available via the POSIX interface.
256    
257    10. Added --line-buffered to pcregrep.
258    
259    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
260        studied, and the match started with a letter with a code point greater than
261        127 whose first byte was different to the first byte of the other case of
262        the letter, the other case of this starting letter was not recognized
263        (#976).
264    
265    12. If a pattern that was studied started with a repeated Unicode property
266        test, for example, \p{Nd}+, there was the theoretical possibility of
267        setting up an incorrect bitmap of starting bytes, but fortunately it could
268        not have actually happened in practice until change 8 above was made (it
269        added property types that matched character-matching opcodes).
270    
271    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
272        possible starting bytes for non-anchored patterns.
273    
274    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
275        \R, and also a number of cases that involve Unicode properties, both
276        explicit and implicit when PCRE_UCP is set.
277    
278    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
279        input, it could crash or give wrong results if characters with values
280        greater than 0xc0 were present in the subject string. (Detail: it assumed
281        UTF-8 input when processing these items.)
282    
283    16. Added a lot of (int) casts to avoid compiler warnings in systems where
284        size_t is 64-bit (#991).
285    
286    17. Added a check for running out of memory when PCRE is compiled with
287        --disable-stack-for-recursion (#990).
288    
289    18. If the last data line in a file for pcretest does not have a newline on
290        the end, a newline was missing in the output.
291    
292    19. The default pcre_chartables.c file recognizes only ASCII characters (values
293        less than 128) in its various bitmaps. However, there is a facility for
294        generating tables according to the current locale when PCRE is compiled. It
295        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
296        characters, are recognized by isspace() and therefore were getting set in
297        these tables, and indeed these tables seem to approximate to ISO 8859. This
298        caused a problem in UTF-8 mode when pcre_study() was used to create a list
299        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
300        which of course cannot start UTF-8 characters. I have changed the code so
301        that only real ASCII characters (less than 128) and the correct starting
302        bytes for UTF-8 encodings are set for characters greater than 127 when in
303        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
304        altogether.)
305    
306    20. Added the /T option to pcretest so as to be able to run tests with non-
307        standard character tables, thus making it possible to include the tests
308        used for 19 above in the standard set of tests.
309    
310    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
311        reference to a subpattern the other side of a comment that contains an
312        opening parenthesis caused either an internal compiling error, or a
313        reference to the wrong subpattern.
314    
315    
316    Version 8.02 19-Mar-2010
317    ------------------------
318    
319    1.  The Unicode data tables have been updated to Unicode 5.2.0.
320    
321    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
322        configured.
323    
324    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
325        original author of that file, following a query about its status.
326    
327    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
328        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
329    
330    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
331        quantifier applied to a forward-referencing subroutine call, could compile
332        incorrect code or give the error "internal error: previously-checked
333        referenced subpattern not found".
334    
335    6.  Both MS Visual Studio and Symbian OS have problems with initializing
336        variables to point to external functions. For these systems, therefore,
337        pcre_malloc etc. are now initialized to local functions that call the
338        relevant global functions.
339    
340    7.  There were two entries missing in the vectors called coptable and poptable
341        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
342        I've fixed the data, and added a kludgy way of testing at compile time that
343        the lengths are correct (equal to the number of opcodes).
344    
345    8.  Following on from 7, I added a similar kludge to check the length of the
346        eint vector in pcreposix.c.
347    
348    9.  Error texts for pcre_compile() are held as one long string to avoid too
349        much relocation at load time. To find a text, the string is searched,
350        counting zeros. There was no check for running off the end of the string,
351        which could happen if a new error number was added without updating the
352        string.
353    
354    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
355    
356    11. \K was not working if it appeared in an atomic group or in a group that
357        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
358        \K is "not well defined" if used in an assertion. PCRE now accepts it if
359        the assertion is positive, but not if it is negative.
360    
361    12. Change 11 fortuitously reduced the size of the stack frame used in the
362        "match()" function of pcre_exec.c by one pointer. Forthcoming
363        implementation of support for (*MARK) will need an extra pointer on the
364        stack; I have reserved it now, so that the stack frame size does not
365        decrease.
366    
367    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
368        item in branch that calls a recursion is a subroutine call - as in the
369        second branch in the above example - was incorrectly given the compile-
370        time error "recursive call could loop indefinitely" because pcre_compile()
371        was not correctly checking the subroutine for matching a non-empty string.
372    
373    14. The checks for overrunning compiling workspace could trigger after an
374        overrun had occurred. This is a "should never occur" error, but it can be
375        triggered by pathological patterns such as hundreds of nested parentheses.
376        The checks now trigger 100 bytes before the end of the workspace.
377    
378    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
379    
380    
381    Version 8.01 19-Jan-2010
382    ------------------------
383    
384    1.  If a pattern contained a conditional subpattern with only one branch (in
385        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
386        computed the wrong minimum data length (which is of course zero for such
387        subpatterns). This could cause incorrect "no match" results.
388    
389    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
390        the pattern is reset in the first branch, pcre_compile() failed with
391        "internal error: code overflow at offset...". This happened only when
392        the reset was to the original external option setting. (An optimization
393        abstracts leading options settings into an external setting, which was the
394        cause of this.)
395    
396    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
397        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
398        assertion pattern did not match (meaning that the assertion was true), it
399        was incorrectly treated as false if the SKIP had been reached during the
400        matching. This also applied to assertions used as conditions.
401    
402    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
403        assertion subpattern, including such a pattern used as a condition,
404        unpredictable results occurred, instead of the error return
405        PCRE_ERROR_DFA_UITEM.
406    
407    5.  The C++ GlobalReplace function was not working like Perl for the special
408        situation when an empty string is matched. It now does the fancy magic
409        stuff that is necessary.
410    
411    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
412        removed. (These were left over from very, very early versions of PCRE.)
413    
414    7.  Some cosmetic changes to the code to make life easier when compiling it
415        as part of something else:
416    
417        (a) Change DEBUG to PCRE_DEBUG.
418    
419        (b) In pcre_compile(), rename the member of the "branch_chain" structure
420            called "current" as "current_branch", to prevent a collision with the
421            Linux macro when compiled as a kernel module.
422    
423        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
424            prevent a collision with the Linux macro when compiled as a kernel
425            module.
426    
427    8.  In pcre_compile() there are some checks for integer overflows that used to
428        cast potentially large values to (double). This has been changed to that
429        when building, a check for int64_t is made, and if it is found, it is used
430        instead, thus avoiding the use of floating point arithmetic. (There is no
431        other use of FP in PCRE.) If int64_t is not found, the fallback is to
432        double.
433    
434    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
435        2005 (difference between two addresses compared to an unsigned value).
436    
437    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
438        custom one, because of the following reported problem in Windows:
439    
440          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
441              under Win32.
442          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
443              therefore missing the function definition.
444          - The compiler thus generates a "C" signature for the test function.
445          - The linker fails to find the "C" function.
446          - PCRE fails to configure if asked to do so against libbz2.
447    
448    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
449        messages were output:
450    
451          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
452          rerunning libtoolize, to keep the correct libtool macros in-tree.
453          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
454    
455        I have done both of these things.
456    
457    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
458        most of the time, it *can* run out if it is given a pattern that contains a
459        runaway infinite recursion. I updated the discussion in the pcrestack man
460        page.
461    
462    13. Now that we have gone to the x.xx style of version numbers, the minor
463        version may start with zero. Using 08 or 09 is a bad idea because users
464        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
465        interpreted as invalid octal numbers. I've updated the previous comment in
466        configure.ac, and also added a check that gives an error if 08 or 09 are
467        used.
468    
469    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
470        causing partial matching to fail when the end of the subject matched \W
471        in a UTF-8 pattern where \W was quantified with a minimum of 3.
472    
473    15. There were some discrepancies between the declarations in pcre_internal.h
474        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
475        their definitions. The declarations used "const uschar *" and the
476        definitions used USPTR. Even though USPTR is normally defined as "const
477        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
478        reported that: "This difference in casting confuses some C++ compilers, for
479        example, SunCC recognizes above declarations as different functions and
480        generates broken code for hbpcre." I have changed the declarations to use
481        USPTR.
482    
483    16. GNU libtool is named differently on some systems. The autogen.sh script now
484        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
485        (FreeBSD).
486    
487    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
488        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
489        comment: "Figure out how to create a longlong from a string: strtoll and
490        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
491        instance, but it only takes 2 args instead of 3!"
492    
493    18. A subtle bug concerned with back references has been fixed by a change of
494        specification, with a corresponding code fix. A pattern such as
495        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
496        refers, was giving matches when it shouldn't. For example, xa=xaaa would
497        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
498        same bug. Such groups have to be quantified to be useful, or contained
499        inside another quantified group. (If there's no repetition, the reference
500        can never match.) The problem arises because, having left the group and
501        moved on to the rest of the pattern, a later failure that backtracks into
502        the group uses the captured value from the final iteration of the group
503        rather than the correct earlier one. I have fixed this in PCRE by forcing
504        any group that contains a reference to itself to be an atomic group; that
505        is, there cannot be any backtracking into it once it has completed. This is
506        similar to recursive and subroutine calls.
507    
508    
509    Version 8.00 19-Oct-09
510    ----------------------
511    
512    1.  The table for translating pcre_compile() error codes into POSIX error codes
513        was out-of-date, and there was no check on the pcre_compile() error code
514        being within the table. This could lead to an OK return being given in
515        error.
516    
517    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
518        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
519        in a Windows environment.
520    
521    3.  The pcregrep --count option prints the count for each file even when it is
522        zero, as does GNU grep. However, pcregrep was also printing all files when
523        --files-with-matches was added. Now, when both options are given, it prints
524        counts only for those files that have at least one match. (GNU grep just
525        prints the file name in this circumstance, but including the count seems
526        more useful - otherwise, why use --count?) Also ensured that the
527        combination -clh just lists non-zero counts, with no names.
528    
529    4.  The long form of the pcregrep -F option was incorrectly implemented as
530        --fixed_strings instead of --fixed-strings. This is an incompatible change,
531        but it seems right to fix it, and I didn't think it was worth preserving
532        the old behaviour.
533    
534    5.  The command line items --regex=pattern and --regexp=pattern were not
535        recognized by pcregrep, which required --regex pattern or --regexp pattern
536        (with a space rather than an '='). The man page documented the '=' forms,
537        which are compatible with GNU grep; these now work.
538    
539    6.  No libpcreposix.pc file was created for pkg-config; there was just
540        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
541    
542    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
543        when UCP support is not needed, by modifying the Python script that
544        generates it from Unicode data files. This should not matter if the module
545        is correctly used as a library, but I received one complaint about 50K of
546        unwanted data. My guess is that the person linked everything into his
547        program rather than using a library. Anyway, it does no harm.
548    
549    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
550        was a minimum greater than 1 for a wide character in a possessive
551        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
552        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
553        character. Chaos in the form of incorrect output or a compiling loop could
554        result.
555    
556    9.  The restrictions on what a pattern can contain when partial matching is
557        requested for pcre_exec() have been removed. All patterns can now be
558        partially matched by this function. In addition, if there are at least two
559        slots in the offset vector, the offset of the earliest inspected character
560        for the match and the offset of the end of the subject are set in them when
561        PCRE_ERROR_PARTIAL is returned.
562    
563    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
564        synonymous with PCRE_PARTIAL, for backwards compatibility, and
565        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
566        and may be more useful for multi-segment matching.
567    
568    11. Partial matching with pcre_exec() is now more intuitive. A partial match
569        used to be given if ever the end of the subject was reached; now it is
570        given only if matching could not proceed because another character was
571        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
572        string "Z", which now yields "no match" instead of "partial match". In the
573        case of pcre_dfa_exec(), "no match" is given if every matching path for the
574        final character ended with (*FAIL).
575    
576    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
577        if the pattern had a "must contain" character that was already found in the
578        earlier partial match, unless partial matching was again requested. For
579        example, with the pattern /dog.(body)?/, the "must contain" character is
580        "g". If the first part-match was for the string "dog", restarting with
581        "sbody" failed. This bug has been fixed.
582    
583    13. The string returned by pcre_dfa_exec() after a partial match has been
584        changed so that it starts at the first inspected character rather than the
585        first character of the match. This makes a difference only if the pattern
586        starts with a lookbehind assertion or \b or \B (\K is not supported by
587        pcre_dfa_exec()). It's an incompatible change, but it makes the two
588        matching functions compatible, and I think it's the right thing to do.
589    
590    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
591        so that the demonstration program is easily available in environments where
592        PCRE has not been installed from source.
593    
594    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
595        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
596        library.
597    
598    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
599        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
600        is not the first non-POSIX option to be added. Clearly some people find
601        these options useful.
602    
603    17. If a caller to the POSIX matching function regexec() passes a non-zero
604        value for nmatch with a NULL value for pmatch, the value of
605        nmatch is forced to zero.
606    
607    18. RunGrepTest did not have a test for the availability of the -u option of
608        the diff command, as RunTest does. It now checks in the same way as
609        RunTest, and also checks for the -b option.
610    
611    19. If an odd number of negated classes containing just a single character
612        interposed, within parentheses, between a forward reference to a named
613        subpattern and the definition of the subpattern, compilation crashed with
614        an internal error, complaining that it could not find the referenced
615        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
616        [The bug was that it was starting one character too far in when skipping
617        over the character class, thus treating the ] as data rather than
618        terminating the class. This meant it could skip too much.]
619    
620    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
621        /g option in pcretest when the pattern contains \K, which makes it possible
622        to have an empty string match not at the start, even when the pattern is
623        anchored. Updated pcretest and pcredemo to use this option.
624    
625    21. If the maximum number of capturing subpatterns in a recursion was greater
626        than the maximum at the outer level, the higher number was returned, but
627        with unset values at the outer level. The correct (outer level) value is
628        now given.
629    
630    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
631        PCRE did not set those parentheses (unlike Perl). I have now found a way to
632        make it do so. The string so far is captured, making this feature
633        compatible with Perl.
634    
635    23. The tests have been re-organized, adding tests 11 and 12, to make it
636        possible to check the Perl 5.10 features against Perl 5.10.
637    
638    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
639        pattern matches a fixed length string. PCRE did not allow this; now it
640        does. Neither allows recursion.
641    
642    25. I finally figured out how to implement a request to provide the minimum
643        length of subject string that was needed in order to match a given pattern.
644        (It was back references and recursion that I had previously got hung up
645        on.) This code has now been added to pcre_study(); it finds a lower bound
646        to the length of subject needed. It is not necessarily the greatest lower
647        bound, but using it to avoid searching strings that are too short does give
648        some useful speed-ups. The value is available to calling programs via
649        pcre_fullinfo().
650    
651    26. While implementing 25, I discovered to my embarrassment that pcretest had
652        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
653        study optimizations had never been tested with that matching function.
654        Oops. What is worse, even when it was passed study data, there was a bug in
655        pcre_dfa_exec() that meant it never actually used it. Double oops. There
656        were also very few tests of studied patterns with pcre_dfa_exec().
657    
658    27. If (?| is used to create subpatterns with duplicate numbers, they are now
659        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
660        on the other side of the coin, they are no longer allowed to have different
661        names, because these cannot be distinguished in PCRE, and this has caused
662        confusion. (This is a difference from Perl.)
663    
664    28. When duplicate subpattern names are present (necessarily with different
665        numbers, as required by 27 above), and a test is made by name in a
666        conditional pattern, either for a subpattern having been matched, or for
667        recursion in such a pattern, all the associated numbered subpatterns are
668        tested, and the overall condition is true if the condition is true for any
669        one of them. This is the way Perl works, and is also more like the way
670        testing by number works.
671    
672    
673    Version 7.9 11-Apr-09
674    ---------------------
675    
676    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
677        (pcretest), all targets were linked against these libraries. This included
678        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
679        libraries. This caused unwanted dependencies to be created. This problem
680        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
681        pcretest is linked with readline.
682    
683    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
684        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
685        moved outside it again, because FALSE and TRUE are already defined in AIX,
686        but BOOL is not.
687    
688    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
689        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
690    
691    4.  The pcregrep documentation said spaces were inserted as well as colons (or
692        hyphens) following file names and line numbers when outputting matching
693        lines. This is not true; no spaces are inserted. I have also clarified the
694        wording for the --colour (or --color) option.
695    
696    5.  In pcregrep, when --colour was used with -o, the list of matching strings
697        was not coloured; this is different to GNU grep, so I have changed it to be
698        the same.
699    
700    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
701        each matching line was coloured. Now it goes on to look for further matches
702        of any of the test patterns, which is the same behaviour as GNU grep.
703    
704    7.  A pattern that could match an empty string could cause pcregrep to loop; it
705        doesn't make sense to accept an empty string match in pcregrep, so I have
706        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
707        seems to be how GNU grep behaves.
708    
709    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
710        start or after a newline", because the conditional assertion was not being
711        correctly handled. The rule now is that both the assertion and what follows
712        in the first alternative must satisfy the test.
713    
714    9.  If auto-callout was enabled in a pattern with a conditional group whose
715        condition was an assertion, PCRE could crash during matching, both with
716        pcre_exec() and pcre_dfa_exec().
717    
718    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
719        used for matching.
720    
721    11. Unicode property support in character classes was not working for
722        characters (bytes) greater than 127 when not in UTF-8 mode.
723    
724    12. Added the -M command line option to pcretest.
725    
726    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
727    
728    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
729    
730    16. Added comments and documentation about mis-use of no_arg in the C++
731        wrapper.
732    
733    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
734        from Martin Jerabek that uses macro names for all relevant character and
735        string constants.
736    
737    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
738        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
739        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
740        these, but not everybody uses configure.
741    
742    19. A conditional group that had only one branch was not being correctly
743        recognized as an item that could match an empty string. This meant that an
744        enclosing group might also not be so recognized, causing infinite looping
745        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
746        with the subject "ab", where knowledge that the repeated group can match
747        nothing is needed in order to break the loop.
748    
749    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
750        exec(), but without supplying a callout function, matching went wrong.
751    
752    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
753        leak if the size of the offset vector was greater than 30. When the vector
754        is smaller, the saved offsets during recursion go onto a local stack
755        vector, but for larger vectors malloc() is used. It was failing to free
756        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
757        error, in fact).
758    
759    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
760        heapframe that is used only when UTF-8 support is enabled. This caused no
761        problem, but was untidy.
762    
763    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
764        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
765        included within another project.
766    
767    24. Steven Van Ingelgem's patches to add more options to the CMake support,
768        slightly modified by me:
769    
770          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
771              not building pcregrep.
772    
773          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
774              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
775    
776    25. Forward references, both numeric and by name, in patterns that made use of
777        duplicate group numbers, could behave incorrectly or give incorrect errors,
778        because when scanning forward to find the reference group, PCRE was not
779        taking into account the duplicate group numbers. A pattern such as
780        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
781    
782    26. Changed a few more instances of "const unsigned char *" to USPTR, making
783        the feature of a custom pointer more persuasive (as requested by a user).
784    
785    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
786        pcretest.c, inside #ifndefs, because it seems they are sometimes already
787        pre-defined.
788    
789    28. Added support for (*UTF8) at the start of a pattern.
790    
791    29. Arrange for flags added by the "release type" setting in CMake to be shown
792        in the configuration summary.
793    
794    
795    Version 7.8 05-Sep-08
796    ---------------------
797    
798    1.  Replaced UCP searching code with optimized version as implemented for Ad
799        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
800        stage table and inline lookup instead of a function, giving speed ups of 2
801        to 5 times on some simple patterns that I tested. Permission was given to
802        distribute the MultiStage2.py script that generates the tables (it's not in
803        the tarball, but is in the Subversion repository).
804    
805    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
806        scripts.
807    
808    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
809        a group with a zero qualifier. The result of the study could be incorrect,
810        or the function might crash, depending on the pattern.
811    
812    4.  Caseless matching was not working for non-ASCII characters in back
813        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
814        It now works when Unicode Property Support is available.
815    
816    5.  In pcretest, an escape such as \x{de} in the data was always generating
817        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
818        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
819        truncation.
820    
821    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
822    
823    7.  Added two (int) casts to pcregrep when printing the difference of two
824        pointers, in case they are 64-bit values.
825    
826    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
827        test 2 if it fails.
828    
829    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
830        and a #define of that name to empty if it is not externally set. This is to
831        allow users of MSVC to set it if necessary.
832    
833    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
834        the convenience functions in the pcre_get.c source file.
835    
836    11. An option change at the start of a pattern that had top-level alternatives
837        could cause overwriting and/or a crash. This command provoked a crash in
838        some environments:
839    
840          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
841    
842        This potential security problem was recorded as CVE-2008-2371.
843    
844    12. For a pattern where the match had to start at the beginning or immediately
845        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
846        pcre_dfa_exec() could read past the end of the passed subject if there was
847        no match. To help with detecting such bugs (e.g. with valgrind), I modified
848        pcretest so that it places the subject at the end of its malloc-ed buffer.
849    
850    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
851        exec() might read past the end of the data buffer in UTF-8 mode.
852    
853    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
854        the data contained the byte 0x85 as part of a UTF-8 character within its
855        first line. This applied both to normal and DFA matching.
856    
857    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
858        /^[^d]*?$/8 failed to match "abc".
859    
860    16. Added a missing copyright notice to pcrecpp_internal.h.
861    
862    17. Make it more clear in the documentation that values returned from
863        pcre_exec() in ovector are byte offsets, not character counts.
864    
865    18. Tidied a few places to stop certain compilers from issuing warnings.
866    
867    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
868        supplied by Stefan Weber. I made a further small update for 7.8 because
869        there is a change of source arrangements: the pcre_searchfuncs.c module is
870        replaced by pcre_ucd.c.
871    
872    
873    Version 7.7 07-May-08
874    ---------------------
875    
876    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
877        a string to a long long, pretend we don't even have a long long." This is
878        done by checking for the strtoq, strtoll, and _strtoi64 functions.
879    
880    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
881        pre-7.6 versions, which defined a global no_arg variable instead of putting
882        it in the RE class. (See also #8 below.)
883    
884    3.  Remove a line of dead code, identified by coverity and reported by Nuno
885        Lopes.
886    
887    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
888    
889        (1) The include/exclude patterns were being applied to the whole pathnames
890            of files, instead of just to the final components.
891    
892        (2) If there was more than one level of directory, the subdirectories were
893            skipped unless they satisfied the include/exclude conditions. This is
894            inconsistent with GNU grep (and could even be seen as contrary to the
895            pcregrep specification - which I improved to make it absolutely clear).
896            The action now is always to scan all levels of directory, and just
897            apply the include/exclude patterns to regular files.
898    
899    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
900        --exclude_dir in the tests to avoid scanning .svn directories.
901    
902    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
903        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
904        doesn't support NULs in patterns.
905    
906    7.  Added some missing "const"s to declarations of static tables in
907        pcre_compile.c and pcre_dfa_exec.c.
908    
909    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
910        caused by fix #2  above. (Subsequently also a second patch to fix the
911        first patch. And a third patch - this was a messy problem.)
912    
913    9.  Applied Craig's patch to remove the use of push_back().
914    
915    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
916        matching function regexec().
917    
918    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
919        which, however, unlike Perl's \g{...}, are subroutine calls, not back
920        references. PCRE supports relative numbers with this syntax (I don't think
921        Oniguruma does).
922    
923    12. Previously, a group with a zero repeat such as (...){0} was completely
924        omitted from the compiled regex. However, this means that if the group
925        was called as a subroutine from elsewhere in the pattern, things went wrong
926        (an internal error was given). Such groups are now left in the compiled
927        pattern, with a new opcode that causes them to be skipped at execution
928        time.
929    
930    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
931        to the way PCRE behaves:
932    
933        (a) A lone ] character is dis-allowed (Perl treats it as data).
934    
935        (b) A back reference to an unmatched subpattern matches an empty string
936            (Perl fails the current match path).
937    
938        (c) A data ] in a character class must be notated as \] because if the
939            first data character in a class is ], it defines an empty class. (In
940            Perl it is not possible to have an empty class.) The empty class []
941            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
942            The negative empty class [^] matches any one character, independently
943            of the DOTALL setting.
944    
945    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
946        non-existent subpattern following a character class starting with ']' and
947        containing () gave an internal compiling error instead of "reference to
948        non-existent subpattern". Fortunately, when the pattern did exist, the
949        compiled code was correct. (When scanning forwards to check for the
950        existencd of the subpattern, it was treating the data ']' as terminating
951        the class, so got the count wrong. When actually compiling, the reference
952        was subsequently set up correctly.)
953    
954    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
955        it was being rejected as not supported by pcre_dfa_exec(), even though
956        other assertions are supported. I have made pcre_dfa_exec() support
957        (*FAIL).
958    
959    16. The implementation of 13c above involved the invention of a new opcode,
960        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
961        cannot be changed at match time, I realized I could make a small
962        improvement to matching performance by compiling OP_ALLANY instead of
963        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
964        on the OP_ANY path.
965    
966    17. Compiling pcretest on Windows with readline support failed without the
967        following two fixes: (1) Make the unistd.h include conditional on
968        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
969    
970    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
971        ncurses library to be included for pcretest when ReadLine support is
972        requested, but also to allow for it to be overridden. This patch came from
973        Daniel Bergström.
974    
975    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
976        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
977        any errors with the current Unicode tables. Thanks to Peter Kankowski for
978        spotting this.
979    
980    
981    Version 7.6 28-Jan-08
982    ---------------------
983    
984    1.  A character class containing a very large number of characters with
985        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
986        overflow.
987    
988    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
989        HAVE_LONG_LONG is not defined.
990    
991    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
992        bring them up to date and include new features. This patch includes:
993    
994        - Fixed PH's badly added libz and libbz2 support.
995        - Fixed a problem with static linking.
996        - Added pcredemo. [But later removed - see 7 below.]
997        - Fixed dftables problem and added an option.
998        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
999            HAVE_LONG_LONG.
1000        - Added readline support for pcretest.
1001        - Added an listing of the option settings after cmake has run.
1002    
1003    4.  A user submitted a patch to Makefile that makes it easy to create
1004        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1005        Makefile.am that cause it to include this special target, without
1006        affecting anything else. Note that the same mingw target plus all
1007        the other distribution libraries and programs are now supported
1008        when configuring with CMake (see 6 below) instead of with
1009        Configure/Make.
1010    
1011    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1012        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1013        exported in the Windows port". It has not yet been confirmed that the patch
1014        solves the problem, but it does no harm.
1015    
1016    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1017        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1018        with CMake, and also correct the comment about stack recursion.
1019    
1020    7.  Remove the automatic building of pcredemo from the ./configure system and
1021        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1022        of a program that users should build themselves after PCRE is installed, so
1023        building it automatically is not really right. What is more, it gave
1024        trouble in some build environments.
1025    
1026    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1027    
1028    
1029    Version 7.5 10-Jan-08
1030    ---------------------
1031    
1032    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1033        values in parens when parsing an RE using the C++ wrapper."
1034    
1035    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1036        Characters greater than 255 were excluded from the class instead of being
1037        included.
1038    
1039    3.  The same bug as (2) above applied to negated POSIX classes such as
1040        [:^space:].
1041    
1042    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1043        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1044        I have changed it.
1045    
1046    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1047        first named subpattern) and a construct such as (?&a) would reference the
1048        first named subpattern whose name started with "a" (in other words, the
1049        length check was missing). Both these problems are fixed. "Subpattern name
1050        expected" is now given for (?&) (a zero-length name), and this patch also
1051        makes it give the same error for \k'' (previously it complained that that
1052        was a reference to a non-existent subpattern).
1053    
1054    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1055        this is right because (?- can be followed by option settings as well as by
1056        digits. I have, however, made the messages clearer.
1057    
1058    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1059        than the number used in the conditional) now cause a compile-time error.
1060        This is actually not compatible with Perl, which accepts such patterns, but
1061        treats the conditional as always being FALSE (as PCRE used to), but it
1062        seems to me that giving a diagnostic is better.
1063    
1064    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1065        and messages.
1066    
1067    9.  Fix two occurrences of "backslash" in comments that should have been
1068        "backspace".
1069    
1070    10. Remove two redundant lines of code that can never be obeyed (their function
1071        was moved elsewhere).
1072    
1073    11. The program that makes PCRE's Unicode character property table had a bug
1074        which caused it to generate incorrect table entries for sequences of
1075        characters that have the same character type, but are in different scripts.
1076        It amalgamated them into a single range, with the script of the first of
1077        them. In other words, some characters were in the wrong script. There were
1078        thirteen such cases, affecting characters in the following ranges:
1079    
1080          U+002b0 - U+002c1
1081          U+0060c - U+0060d
1082          U+0061e - U+00612
1083          U+0064b - U+0065e
1084          U+0074d - U+0076d
1085          U+01800 - U+01805
1086          U+01d00 - U+01d77
1087          U+01d9b - U+01dbf
1088          U+0200b - U+0200f
1089          U+030fc - U+030fe
1090          U+03260 - U+0327f
1091          U+0fb46 - U+0fbb1
1092          U+10450 - U+1049d
1093    
1094    12. The -o option (show only the matching part of a line) for pcregrep was not
1095        compatible with GNU grep in that, if there was more than one match in a
1096        line, it showed only the first of them. It now behaves in the same way as
1097        GNU grep.
1098    
1099    13. If the -o and -v options were combined for pcregrep, it printed a blank
1100        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1101        does the same. The return code can be used to tell if there were any
1102        non-matching lines.
1103    
1104    14. Added --file-offsets and --line-offsets to pcregrep.
1105    
1106    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1107        infinitely looping recursion. The bug was that positive lookaheads were not
1108        being skipped when checking for a possible empty match (negative lookaheads
1109        and both kinds of lookbehind were skipped).
1110    
1111    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1112        inclusion of <windows.h> to before rather than after the definition of
1113        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1114    
1115    17. Specifying a possessive quantifier with a specific limit for a Unicode
1116        character property caused pcre_compile() to compile bad code, which led at
1117        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1118        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1119        caused the error; without that there was no problem.
1120    
1121    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1122    
1123    19. Added --enable-pcretest-libreadline.
1124    
1125    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1126        RE::GlobalReplace(). As a result, the number of replacements returned was
1127        double what it should be. I removed one of the increments, but Craig sent a
1128        later patch that removed the other one (the right fix) and added unit tests
1129        that check the return values (which was not done before).
1130    
1131    21. Several CMake things:
1132    
1133        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1134            the names libpcre and libpcreposix, not just pcre and pcreposix.
1135    
1136        (2) The above change means that pcretest and pcregrep are now correctly
1137            linked with the newly-built libraries, not previously installed ones.
1138    
1139        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
1140    
1141    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1142        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1143        UTF-8 newline character). The key issue is that the pattern starts .*;
1144        this means that the match must be either at the beginning, or after a
1145        newline. The bug was in the code for advancing after a failed match and
1146        checking that the new position followed a newline. It was not taking
1147        account of UTF-8 characters correctly.
1148    
1149    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1150        character classes. PCRE was not treating the sequence [:...:] as a
1151        character class unless the ... were all letters. Perl, however, seems to
1152        allow any characters between [: and :], though of course it rejects as
1153        unknown any "names" that contain non-letters, because all the known class
1154        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1155        for example, whereas PCRE did not - it did not recognize a POSIX character
1156        class. This seemed a bit dangerous, so the code has been changed to be
1157        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1158        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1159        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1160        Perl does, and where it didn't before.
1161    
1162    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1163        Windows environments %n is disabled by default.
1164    
1165    
1166    Version 7.4 21-Sep-07
1167    ---------------------
1168    
1169    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1170        means that a class such as [\s] counted as "explicit reference to CR or
1171        LF". That isn't really right - the whole point of the change was to try to
1172        help when there was an actual mention of one of the two characters. So now
1173        the change happens only if \r or \n (or a literal CR or LF) character is
1174        encountered.
1175    
1176    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1177        of both had grown to the point where there were only 3 bits left.
1178        Fortunately, there was spare space in the data structure, and so I have
1179        moved the internal flags into a new 16-bit field to free up more option
1180        bits.
1181    
1182    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1183        but did not set the internal JCHANGED flag - either of these is enough to
1184        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1185        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1186        start sets both bits.
1187    
1188    4.  Added options (at build time, compile time, exec time) to change \R from
1189        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1190    
1191    5.  doc/pcresyntax.html was missing from the distribution.
1192    
1193    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1194        compatibility, even though it is no longer used.
1195    
1196    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1197        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1198        windows.h file is present (where different names are used). [This was
1199        reversed later after testing - see 16 below.]
1200    
1201    8.  Changed all #include <config.h> to #include "config.h". There were also
1202        some further <pcre.h> cases that I changed to "pcre.h".
1203    
1204    9.  When pcregrep was used with the --colour option, it missed the line ending
1205        sequence off the lines that it output.
1206    
1207    10. It was pointed out to me that arrays of string pointers cause lots of
1208        relocations when a shared library is dynamically loaded. A technique of
1209        using a single long string with a table of offsets can drastically reduce
1210        these. I have refactored PCRE in four places to do this. The result is
1211        dramatic:
1212    
1213          Originally:                          290
1214          After changing UCP table:            187
1215          After changing error message table:   43
1216          After changing table of "verbs"       36
1217          After changing table of Posix names   22
1218    
1219        Thanks to the folks working on Gregex for glib for this insight.
1220    
1221    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1222        unicode-properties was also set.
1223    
1224    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1225    
1226    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1227        checked only for CRLF.
1228    
1229    14. Added casts to pcretest.c to avoid compiler warnings.
1230    
1231    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1232    
1233    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1234        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1235        entirely. This removes changes made in 7 above.
1236    
1237    17. The CMake files have been updated, and there is now more information about
1238        building with CMake in the NON-UNIX-USE document.
1239    
1240    
1241    Version 7.3 28-Aug-07
1242    ---------------------
1243    
1244     1. In the rejigging of the build system that eventually resulted in 7.1, the
1245        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1246        brackets there is not right, since it causes compilers to look for an
1247        installed pcre.h, not the version that is in the source that is being
1248        compiled (which of course may be different). I have changed it back to:
1249    
1250          #include "pcre.h"
1251    
1252        I have a vague recollection that the change was concerned with compiling in
1253        different directories, but in the new build system, that is taken care of
1254        by the VPATH setting the Makefile.
1255    
1256     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1257        when the subject happened to end in the byte 0x85 (e.g. if the last
1258        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1259        characters but of course it shouldn't be taken as a newline when it is part
1260        of another character. The bug was that, for an unlimited repeat of . in
1261        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1262        characters when looking for a newline.
1263    
1264     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1265    
1266     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1267        in debug output.
1268    
1269     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1270        long printing in the pcrecpp unittest when running under MinGW.
1271    
1272     6. ESC_K was left out of the EBCDIC table.
1273    
1274     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1275        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1276        limit also applies to "virtual nesting" when a pattern is recursive, and in
1277        this case 1000 isn't so big. I have been able to remove this limit at the
1278        expense of backing off one optimization in certain circumstances. Normally,
1279        when pcre_exec() would call its internal match() function recursively and
1280        immediately return the result unconditionally, it uses a "tail recursion"
1281        feature to save stack. However, when a subpattern that can match an empty
1282        string has an unlimited repetition quantifier, it no longer makes this
1283        optimization. That gives it a stack frame in which to save the data for
1284        checking that an empty string has been matched. Previously this was taken
1285        from the 1000-entry workspace that had been reserved. So now there is no
1286        explicit limit, but more stack is used.
1287    
1288     8. Applied Daniel's patches to solve problems with the import/export magic
1289        syntax that is required for Windows, and which was going wrong for the
1290        pcreposix and pcrecpp parts of the library. These were overlooked when this
1291        problem was solved for the main library.
1292    
1293     9. There were some crude static tests to avoid integer overflow when computing
1294        the size of patterns that contain repeated groups with explicit upper
1295        limits. As the maximum quantifier is 65535, the maximum group length was
1296        set at 30,000 so that the product of these two numbers did not overflow a
1297        32-bit integer. However, it turns out that people want to use groups that
1298        are longer than 30,000 bytes (though not repeat them that many times).
1299        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1300        made it possible to implement the integer overflow checks in a much more
1301        dynamic way, which I have now done. The artificial limitation on group
1302        length has been removed - we now have only the limit on the total length of
1303        the compiled pattern, which depends on the LINK_SIZE setting.
1304    
1305    10. Fixed a bug in the documentation for get/copy named substring when
1306        duplicate names are permitted. If none of the named substrings are set, the
1307        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1308        empty string.
1309    
1310    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1311        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1312        because the ] is interpreted as the first data character and the
1313        terminating ] is not found. PCRE has been made compatible with Perl in this
1314        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1315        cause memory overwriting.
1316    
1317    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1318        string has been matched (to stop an infinite loop). It was not recognizing
1319        a conditional subpattern that could match an empty string if that
1320        subpattern was within another subpattern. For example, it looped when
1321        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1322        condition was not nested. This bug has been fixed.
1323    
1324    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1325        past the start of the subject in the presence of bytes with the top bit
1326        set, for example "\x8aBCD".
1327    
1328    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1329        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1330    
1331    14. Optimized (?!) to (*FAIL).
1332    
1333    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1334        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1335        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1336        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1337        does: it's just the validity check that is more restrictive.
1338    
1339    16. Inserted checks for integer overflows during escape sequence (backslash)
1340        processing, and also fixed erroneous offset values for syntax errors during
1341        backslash processing.
1342    
1343    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1344        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1345    
1346    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1347        caused an overrun.
1348    
1349    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1350        something other than just ASCII characters) inside a group that had an
1351        unlimited repeat caused a loop at compile time (while checking to see
1352        whether the group could match an empty string).
1353    
1354    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1355        [\P{Any}] did so. (Error in the code for printing property names.)
1356    
1357    21. An orphan \E inside a character class could cause a crash.
1358    
1359    22. A repeated capturing bracket such as (A)? could cause a wild memory
1360        reference during compilation.
1361    
1362    23. There are several functions in pcre_compile() that scan along a compiled
1363        expression for various reasons (e.g. to see if it's fixed length for look
1364        behind). There were bugs in these functions when a repeated \p or \P was
1365        present in the pattern. These operators have additional parameters compared
1366        with \d, etc, and these were not being taken into account when moving along
1367        the compiled data. Specifically:
1368    
1369        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1370            length.
1371    
1372        (b) An item such as \pL+ within a repeated group could cause crashes or
1373            loops.
1374    
1375        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1376            "reference to non-existent subpattern" error.
1377    
1378        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1379    
1380    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1381        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1382    
1383    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1384    
1385    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1386        character were causing crashes (broken optimization).
1387    
1388    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1389        \p or \P) caused a compile-time loop.
1390    
1391    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1392        break. For example, the unstudied pattern [\r\n]A does not match the string
1393        "\r\nA" because change 7.0/46 below moves the current point on by two
1394        characters after failing to match at the start. However, the pattern \nA
1395        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1396        the same is true. There doesn't seem any very clean way out of this, but
1397        what I have chosen to do makes the common cases work: PCRE now takes note
1398        of whether there can be an explicit match for \r or \n anywhere in the
1399        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1400        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1401        pattern has explicit CR or LF references.
1402    
1403    29. Added (*CR) etc for changing newline setting at start of pattern.
1404    
1405    
1406    Version 7.2 19-Jun-07
1407    ---------------------
1408    
1409     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1410        which is apparently normally available under Windows.
1411    
1412     2. Re-jig the pcregrep tests with different newline settings in an attempt
1413        to make them independent of the local environment's newline setting.
1414    
1415     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1416    
1417     4. Some of the "internals" tests were previously cut out when the link size
1418        was not 2, because the output contained actual offsets. The recent new
1419        "Z" feature of pcretest means that these can be cut out, making the tests
1420        usable with all link sizes.
1421    
1422     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1423        stack recursion. This gives a massive performance boost under BSD, but just
1424        a small improvement under Linux. However, it saves one field in the frame
1425        in all cases.
1426    
1427     6. Added more features from the forthcoming Perl 5.10:
1428    
1429        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1430            recursion call. It refers to the nth most recently opened parentheses.
1431    
1432        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1433            to be opened parentheses.
1434    
1435        (c) Conditions that refer to capturing parentheses can be specified
1436            relatively, for example, (?(-2)... or (?(+3)...
1437    
1438        (d) \K resets the start of the current match so that everything before
1439            is not part of it.
1440    
1441        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1442    
1443        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1444            reference syntax.
1445    
1446        (g) (?| introduces a group in which the numbering of parentheses in each
1447            alternative starts with the same number.
1448    
1449        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1450    
1451     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1452        PCRE_INFO_JCHANGED.
1453    
1454     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1455        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1456        for detecting groups that can match an empty string.
1457    
1458     9. A pattern with a very large number of alternatives (more than several
1459        hundred) was running out of internal workspace during the pre-compile
1460        phase, where pcre_compile() figures out how much memory will be needed. A
1461        bit of new cunning has reduced the workspace needed for groups with
1462        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1463        workspace instead of running out of the 4096 that are available.
1464    
1465    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1466    
1467    11. Applied patch from Google to remove an optimization that didn't quite work.
1468        The report of the bug said:
1469    
1470          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1471          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1472          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1473    
1474    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1475        it matched the wrong number of bytes.
1476    
1477    
1478    Version 7.1 24-Apr-07
1479    ---------------------
1480    
1481     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1482        that is more "standard", making use of automake and other Autotools. There
1483        is some re-arrangement of the files and adjustment of comments consequent
1484        on this.
1485    
1486     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1487        for recursive directory scanning broke on some systems because the files
1488        are not scanned in any specific order and on different systems the order
1489        was different. A call to "sort" has been inserted into RunGrepTest for the
1490        approprate test as a short-term fix. In the longer term there may be an
1491        alternative.
1492    
1493     3. I had an email from Eric Raymond about problems translating some of PCRE's
1494        man pages to HTML (despite the fact that I distribute HTML pages, some
1495        people do their own conversions for various reasons). The problems
1496        concerned the use of low-level troff macros .br and .in. I have therefore
1497        removed all such uses from the man pages (some were redundant, some could
1498        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1499        HTML has been updated to handle .nf/.fi and to complain if it encounters
1500        .br or .in.
1501    
1502     4. Updated comments in configure.ac that get placed in config.h.in and also
1503        arranged for config.h to be included in the distribution, with the name
1504        config.h.generic, for the benefit of those who have to compile without
1505        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1506    
1507     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1508        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1509        makevp.bat for the current PCRE, using the additional files
1510        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1511    
1512     6. A Windows user reported a minor discrepancy with test 2, which turned out
1513        to be caused by a trailing space on an input line that had got lost in his
1514        copy. The trailing space was an accident, so I've just removed it.
1515    
1516     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1517        that is needed.
1518    
1519     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1520        as "const" (a) because they are and (b) because it helps the PHP
1521        maintainers who have recently made a script to detect big data structures
1522        in the php code that should be moved to the .rodata section. I remembered
1523        to update Builducptable as well, so it won't revert if ucptable.h is ever
1524        re-created.
1525    
1526     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1527        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1528        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1529        support is not required. This saves 1.5-2K of code, which is important in
1530        some applications.
1531    
1532        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1533        so as not to refer to the tables, even though these functions will never be
1534        called when UTF-8 support is disabled. Otherwise there are problems with a
1535        shared library.
1536    
1537    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1538    
1539        (a) It was defining its arguments as char * instead of void *.
1540    
1541        (b) It was assuming that all moves were upwards in memory; this was true
1542            a long time ago when I wrote it, but is no longer the case.
1543    
1544        The emulated memove() is provided for those environments that have neither
1545        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1546        is clearly not the case, as these two bugs were recently reported.
1547    
1548    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1549        and Detrail to create the HTML documentation, the .txt form of the man
1550        pages, and it removes trailing spaces from listed files. It also creates
1551        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1552        case, it wraps all the #defines with #ifndefs. This script should be run
1553        before "make dist".
1554    
1555    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1556        with Unicode property support.
1557    
1558        (a) For a maximizing quantifier, if the two different cases of the
1559            character were of different lengths in their UTF-8 codings (there are
1560            some cases like this - I found 11), and the matching function had to
1561            back up over a mixture of the two cases, it incorrectly assumed they
1562            were both the same length.
1563    
1564        (b) When PCRE was configured to use the heap rather than the stack for
1565            recursion during matching, it was not correctly preserving the data for
1566            the other case of a UTF-8 character when checking ahead for a match
1567            while processing a minimizing repeat. If the check also involved
1568            matching a wide character, but failed, corruption could cause an
1569            erroneous result when trying to check for a repeat of the original
1570            character.
1571    
1572    13. Some tidying changes to the testing mechanism:
1573    
1574        (a) The RunTest script now detects the internal link size and whether there
1575            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1576            values substituted by "configure". (The RunGrepTest script already did
1577            this for UTF-8.) The configure.ac script no longer substitutes the
1578            relevant variables.
1579    
1580        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1581            with length and offset values. This means that the output is different
1582            for different internal link sizes. Test 2 is skipped for link sizes
1583            other than 2 because of this, bypassing the problem. Unfortunately,
1584            there was also a test in test 3 (the locale tests) that used /B and
1585            failed for link sizes other than 2. Rather than cut the whole test out,
1586            I have added a new /Z option to pcretest that replaces the length and
1587            offset values with spaces. This is now used to make test 3 independent
1588            of link size. (Test 2 will be tidied up later.)
1589    
1590    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1591        segmentation fault instead of returning the appropriate error message.
1592    
1593    15. In multiline mode when the newline sequence was set to "any", the pattern
1594        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1595        This doesn't seem right; it now treats the CRLF combination as the line
1596        ending, and so does not match in that case. It's only a pattern such as ^$
1597        that would hit this one: something like ^ABC$ would have failed after \r
1598        and then tried again after \r\n.
1599    
1600    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1601        in an attempt to make files that differ only in their line terminators
1602        compare equal. This works on Linux.
1603    
1604    17. Under certain error circumstances pcregrep might try to free random memory
1605        as it exited. This is now fixed, thanks to valgrind.
1606    
1607    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1608        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1609        was because its rules for how to advance for /g after matching an empty
1610        string at the end of a line did not allow for this case. They now check for
1611        it specially.
1612    
1613    20. pcretest is supposed to handle patterns and data of any length, by
1614        extending its buffers when necessary. It was getting this wrong when the
1615        buffer for a data line had to be extended.
1616    
1617    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1618        CRLF as a newline sequence.
1619    
1620    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1621        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1622        I have nevertheless tidied it up.
1623    
1624    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1625    
1626    24. Added a man page for pcre-config.
1627    
1628    
1629    Version 7.0 19-Dec-06
1630    ---------------------
1631    
1632     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1633        moving to gcc 4.1.1.
1634    
1635     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1636        sys/time.h, which is documented as needed for this function. It doesn't
1637        seem to matter on Linux, but it showed up on some releases of OS X.
1638    
1639     3. It seems that there are systems where bytes whose values are greater than
1640        127 match isprint() in the "C" locale. The "C" locale should be the
1641        default when a C program starts up. In most systems, only ASCII printing
1642        characters match isprint(). This difference caused the output from pcretest
1643        to vary, making some of the tests fail. I have changed pcretest so that:
1644    
1645        (a) When it is outputting text in the compiled version of a pattern, bytes
1646            other than 32-126 are always shown as hex escapes.
1647    
1648        (b) When it is outputting text that is a matched part of a subject string,
1649            it does the same, unless a different locale has been set for the match
1650            (using the /L modifier). In this case, it uses isprint() to decide.
1651    
1652     4. Fixed a major bug that caused incorrect computation of the amount of memory
1653        required for a compiled pattern when options that changed within the
1654        pattern affected the logic of the preliminary scan that determines the
1655        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1656        that the computed length was too small. The symptoms of this bug were
1657        either the PCRE error "internal error: code overflow" from pcre_compile(),
1658        or a glibc crash with a message such as "pcretest: free(): invalid next
1659        size (fast)". Examples of patterns that provoked this bug (shown in
1660        pcretest format) are:
1661    
1662          /(?-x: )/x
1663          /(?x)(?-x: \s*#\s*)/
1664          /((?i)[\x{c0}])/8
1665          /(?i:[\x{c0}])/8
1666    
1667        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1668        is now done differently.
1669    
1670     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1671        wrapper classes; (b) implement a new function in the C++ scanner that is
1672        more efficient than the old way of doing things because it avoids levels of
1673        recursion in the regex matching; (c) add a paragraph to the documentation
1674        for the FullMatch() function.
1675    
1676     6. The escape sequence \n was being treated as whatever was defined as
1677        "newline". Not only was this contrary to the documentation, which states
1678        that \n is character 10 (hex 0A), but it also went horribly wrong when
1679        "newline" was defined as CRLF. This has been fixed.
1680    
1681     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1682        was being set to -1 for the "end of line" case (supposedly a value that no
1683        character can have). Though this value is never used (the check for end of
1684        line is "zero bytes in current character"), it caused compiler complaints.
1685        I've changed it to 0xffffffff.
1686    
1687     8. In pcre_version.c, the version string was being built by a sequence of
1688        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1689        string (as it is for production releases) called a macro with an empty
1690        argument. The C standard says the result of this is undefined. The gcc
1691        compiler treats it as an empty string (which was what was wanted) but it is
1692        reported that Visual C gives an error. The source has been hacked around to
1693        avoid this problem.
1694    
1695     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1696        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1697        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1698        of them did).
1699    
1700    10. Originally, pcretest opened its input and output without "b"; then I was
1701        told that "b" was needed in some environments, so it was added for release
1702        5.0 to both the input and output. (It makes no difference on Unix-like
1703        systems.) Later I was told that it is wrong for the input on Windows. I've
1704        now abstracted the modes into two macros, to make it easier to fiddle with
1705        them, and removed "b" from the input mode under Windows.
1706    
1707    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1708    
1709    12. Added -help and --help to pcretest as an official way of being reminded
1710        of the options.
1711    
1712    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1713        and pcrecpp.cc because they annoy compilers at high warning levels.
1714    
1715    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1716    
1717    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1718        scripts are not C programs :-) and which was not noticed because it works
1719        on Linux.
1720    
1721    16. pcretest is supposed to handle any length of pattern and data line (as one
1722        line or as a continued sequence of lines) by extending its input buffer if
1723        necessary. This feature was broken for very long pattern lines, leading to
1724        a string of junk being passed to pcre_compile() if the pattern was longer
1725        than about 50K.
1726    
1727    17. I have done a major re-factoring of the way pcre_compile() computes the
1728        amount of memory needed for a compiled pattern. Previously, there was code
1729        that made a preliminary scan of the pattern in order to do this. That was
1730        OK when PCRE was new, but as the facilities have expanded, it has become
1731        harder and harder to keep it in step with the real compile phase, and there
1732        have been a number of bugs (see for example, 4 above). I have now found a
1733        cunning way of running the real compile function in a "fake" mode that
1734        enables it to compute how much memory it would need, while actually only
1735        ever using a few hundred bytes of working memory and without too many
1736        tests of the mode. This should make future maintenance and development
1737        easier. A side effect of this work is that the limit of 200 on the nesting
1738        depth of parentheses has been removed (though this was never a serious
1739        limitation, I suspect). However, there is a downside: pcre_compile() now
1740        runs more slowly than before (30% or more, depending on the pattern). I
1741        hope this isn't a big issue. There is no effect on runtime performance.
1742    
1743    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1744        newline (only possible for the last line of a file) and it was a
1745        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1746    
1747    19. Added additional timing features to pcretest. (1) The -tm option now times
1748        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1749        separate command line item, by a number that specifies the number of
1750        repeats to use when timing. The default is 50000; this gives better
1751        precision, but takes uncomfortably long for very large patterns.
1752    
1753    20. Extended pcre_study() to be more clever in cases where a branch of a
1754        subpattern has no definite first character. For example, (a*|b*)[cd] would
1755        previously give no result from pcre_study(). Now it recognizes that the
1756        first character must be a, b, c, or d.
1757    
1758    21. There was an incorrect error "recursive call could loop indefinitely" if
1759        a subpattern (or the entire pattern) that was being tested for matching an
1760        empty string contained only one non-empty item after a nested subpattern.
1761        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1762        incorrectly, because the \d was being skipped in the check.
1763    
1764    22. The pcretest program now has a new pattern option /B and a command line
1765        option -b, which is equivalent to adding /B to every pattern. This causes
1766        it to show the compiled bytecode, without the additional information that
1767        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1768        is the same as /B/I).
1769    
1770    23. A new optimization is now able automatically to treat some sequences such
1771        as a*b as a*+b. More specifically, if something simple (such as a character
1772        or a simple class like \d) has an unlimited quantifier, and is followed by
1773        something that cannot possibly match the quantified thing, the quantifier
1774        is automatically "possessified".
1775    
1776    24. A recursive reference to a subpattern whose number was greater than 39
1777        went wrong under certain circumstances in UTF-8 mode. This bug could also
1778        have affected the operation of pcre_study().
1779    
1780    25. Realized that a little bit of performance could be had by replacing
1781        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1782    
1783    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1784    
1785    27. Possessive quantifiers such as a++ were previously implemented by turning
1786        them into atomic groups such as ($>a+). Now they have their own opcodes,
1787        which improves performance. This includes the automatically created ones
1788        from 23 above.
1789    
1790    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1791        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1792        the first matched character to be a colon. This applied both to named and
1793        numbered groups.
1794    
1795    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1796    
1797    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1798        building PCRE on Windows easier, so I have included it in the distribution.
1799    
1800    31. There is now a check in pcretest against a ridiculously large number being
1801        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1802        loop, the loop is abandoned.
1803    
1804    32. Forward references to subpatterns in conditions such as (?(2)...) where
1805        subpattern 2 is defined later cause pcre_compile() to search forwards in
1806        the pattern for the relevant set of parentheses. This search went wrong
1807        when there were unescaped parentheses in a character class, parentheses
1808        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1809    
1810    33. "Subroutine" calls and backreferences were previously restricted to
1811        referencing subpatterns earlier in the regex. This restriction has now
1812        been removed.
1813    
1814    34. Added a number of extra features that are going to be in Perl 5.10. On the
1815        whole, these are just syntactic alternatives for features that PCRE had
1816        previously implemented using the Python syntax or my own invention. The
1817        other formats are all retained for compatibility.
1818    
1819        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1820            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1821            also .NET compatible.
1822    
1823        (b) A recursion or subroutine call to a named group can now be defined as
1824            (?&name) as well as (?P>name).
1825    
1826        (c) A backreference to a named group can now be defined as \k<name> or
1827            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1828            5.10, are also .NET compatible.
1829    
1830        (d) A conditional reference to a named group can now use the syntax
1831            (?(<name>) or (?('name') as well as (?(name).
1832    
1833        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1834            groups (named and numbered) that are never evaluated inline, but can be
1835            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1836            is always false. There may be only one alternative in such a group.
1837    
1838        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1839            as the simple (?(R). The condition is true only if the most recent
1840            recursion is that of the given number or name. It does not search out
1841            through the entire recursion stack.
1842    
1843        (g) The escape \gN or \g{N} has been added, where N is a positive or
1844            negative number, specifying an absolute or relative reference.
1845    
1846    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1847        some "unreachable code" warnings.
1848    
1849    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1850        things, this adds five new scripts.
1851    
1852    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1853        There were also incompatibilities regarding the handling of \Q..\E inside
1854        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1855        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1856    
1857    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1858        matches an empty string, and forcibly breaks the loop. There were bugs in
1859        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1860        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1861        separate and independent bugs (that affected different cases) have been
1862        fixed.
1863    
1864    39. Refactored the code to abolish the use of different opcodes for small
1865        capturing bracket numbers. This is a tidy that I avoided doing when I
1866        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1867        The new approach is not only tidier, it makes it possible to reduce the
1868        memory needed to fix the previous bug (38).
1869    
1870    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1871        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1872        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1873        mode.
1874    
1875    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1876        report.
1877    
1878    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1879        copy construction and assignment in the C++ wrapper.
1880    
1881    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1882        couple of bugs that could have given wrong results in the "--newline=crlf"
1883        case.
1884    
1885    44. Added a number of casts and did some reorganization of signed/unsigned int
1886        variables following suggestions from Dair Grant. Also renamed the variable
1887        "this" as "item" because it is a C++ keyword.
1888    
1889    45. Arranged for dftables to add
1890    
1891          #include "pcre_internal.h"
1892    
1893        to pcre_chartables.c because without it, gcc 4.x may remove the array
1894        definition from the final binary if PCRE is built into a static library and
1895        dead code stripping is activated.
1896    
1897    46. For an unanchored pattern, if a match attempt fails at the start of a
1898        newline sequence, and the newline setting is CRLF or ANY, and the next two
1899        characters are CRLF, advance by two characters instead of one.
1900    
1901    
1902    Version 6.7 04-Jul-06
1903    ---------------------
1904    
1905     1. In order to handle tests when input lines are enormously long, pcretest has
1906        been re-factored so that it automatically extends its buffers when
1907        necessary. The code is crude, but this _is_ just a test program. The
1908        default size has been increased from 32K to 50K.
1909    
1910     2. The code in pcre_study() was using the value of the re argument before
1911        testing it for NULL. (Of course, in any sensible call of the function, it
1912        won't be NULL.)
1913    
1914     3. The memmove() emulation function in pcre_internal.h, which is used on
1915        systems that lack both memmove() and bcopy() - that is, hardly ever -
1916        was missing a "static" storage class specifier.
1917    
1918     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1919        containing an extended class (one that cannot be represented by a bitmap
1920        because it contains high-valued characters or Unicode property items, e.g.
1921        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1922        pattern, but PCRE should not loop if you do not (it no longer does).
1923        [Detail: two cases were found: (a) a repeated subpattern containing an
1924        extended class; (b) a recursive reference to a subpattern that followed a
1925        previous extended class. It wasn't skipping over the extended class
1926        correctly when UTF-8 mode was not set.]
1927    
1928     5. A negated single-character class was not being recognized as fixed-length
1929        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1930        compile error "lookbehind assertion is not fixed length".
1931    
1932     6. The RunPerlTest auxiliary script was showing an unexpected difference
1933        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1934        write a Perl script that can interpret lines of an input file either as
1935        byte characters or as UTF-8, which is what "perltest" was being required to
1936        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1937        can't do is switch easily at run time between having the "use utf8;" pragma
1938        or not. In the end, I fudged it by using the RunPerlTest script to insert
1939        "use utf8;" explicitly for the UTF-8 tests.
1940    
1941     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1942        the end of the subject string, contrary to the documentation and to what
1943        Perl does. This was true of both matching functions. Now it matches only at
1944        the start of the subject and immediately after *internal* newlines.
1945    
1946     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1947        a pointer to an int instead of a pointer to an unsigned long int. This
1948        caused problems on 64-bit systems.
1949    
1950     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1951        instance of the 'standard' template library not being so standard".
1952    
1953    10. There was no check on the number of named subpatterns nor the maximum
1954        length of a subpattern name. The product of these values is used to compute
1955        the size of the memory block for a compiled pattern. By supplying a very
1956        long subpattern name and a large number of named subpatterns, the size
1957        computation could be caused to overflow. This is now prevented by limiting
1958        the length of names to 32 characters, and the number of named subpatterns
1959        to 10,000.
1960    
1961    11. Subpatterns that are repeated with specific counts have to be replicated in
1962        the compiled pattern. The size of memory for this was computed from the
1963        length of the subpattern and the repeat count. The latter is limited to
1964        65535, but there was no limit on the former, meaning that integer overflow
1965        could in principle occur. The compiled length of a repeated subpattern is
1966        now limited to 30,000 bytes in order to prevent this.
1967    
1968    12. Added the optional facility to have named substrings with the same name.
1969    
1970    13. Added the ability to use a named substring as a condition, using the
1971        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1972        are numbers (not recommended). Forward references are permitted.
1973    
1974    14. Added forward references in named backreferences (if you see what I mean).
1975    
1976    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1977        pattern could run off the end of the subject. For example, the pattern
1978        "(?s)(.{1,5})"8 did this with the subject "ab".
1979    
1980    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1981        PCRE_CASELESS was set when matching characters that were quantified with ?
1982        or *.
1983    
1984    17. A character class other than a single negated character that had a minimum
1985        but no maximum quantifier - for example [ab]{6,} - was not handled
1986        correctly by pce_dfa_exec(). It would match only one character.
1987    
1988    18. A valid (though odd) pattern that looked like a POSIX character
1989        class but used an invalid character after [ (for example [[,abc,]]) caused
1990        pcre_compile() to give the error "Failed: internal error: code overflow" or
1991        in some cases to crash with a glibc free() error. This could even happen if
1992        the pattern terminated after [[ but there just happened to be a sequence of
1993        letters, a binary zero, and a closing ] in the memory that followed.
1994    
1995    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1996        over the years. Originally (before any Unicode support), just the bottom 8
1997        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1998        output from "man perlunicode" includes this:
1999    
2000          The regular expression compiler produces polymorphic opcodes.  That
2001          is, the pattern adapts to the data and automatically switches to
2002          the Unicode character scheme when presented with Unicode data--or
2003          instead uses a traditional byte scheme when presented with byte
2004          data.
2005    
2006        Sadly, a wide octal escape does not cause a switch, and in a string with
2007        no other multibyte characters, these octal escapes are treated as before.
2008        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
2009        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
2010        Unicode string.
2011    
2012        I have not perpetrated such confusion in PCRE. Up till now, it took just
2013        the bottom 8 bits, as in old Perl. I have now made octal escapes with
2014        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
2015        translate to the appropriate multibyte character.
2016    
2017    29. Applied some refactoring to reduce the number of warnings from Microsoft
2018        and Borland compilers. This has included removing the fudge introduced
2019        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
2020        a warning about an unused variable.
2021    
2022    21. PCRE has not included VT (character 0x0b) in the set of whitespace
2023        characters since release 4.0, because Perl (from release 5.004) does not.
2024        [Or at least, is documented not to: some releases seem to be in conflict
2025        with the documentation.] However, when a pattern was studied with
2026        pcre_study() and all its branches started with \s, PCRE still included VT
2027        as a possible starting character. Of course, this did no harm; it just
2028        caused an unnecessary match attempt.
2029    
2030    22. Removed a now-redundant internal flag bit that recorded the fact that case
2031        dependency changed within the pattern. This was once needed for "required
2032        byte" processing, but is no longer used. This recovers a now-scarce options
2033        bit. Also moved the least significant internal flag bit to the most-
2034        significant bit of the word, which was not previously used (hangover from
2035        the days when it was an int rather than a uint) to free up another bit for
2036        the future.
2037    
2038    23. Added support for CRLF line endings as well as CR and LF. As well as the
2039        default being selectable at build time, it can now be changed at runtime
2040        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
2041        specify that it is scanning data with non-default line endings.
2042    
2043    24. Changed the definition of CXXLINK to make it agree with the definition of
2044        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
2045    
2046    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
2047        recursions. This makes a big different to stack usage for some patterns.
2048    
2049    26. If a subpattern containing a named recursion or subroutine reference such
2050        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
2051        the space required for the compiled pattern went wrong and gave too small a
2052        value. Depending on the environment, this could lead to "Failed: internal
2053        error: code overflow at offset 49" or "glibc detected double free or
2054        corruption" errors.
2055    
2056    27. Applied patches from Google (a) to support the new newline modes and (b) to
2057        advance over multibyte UTF-8 characters in GlobalReplace.
2058    
2059    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
2060        difference for some implementation of PCRE in some Windows version.
2061    
2062    29. Added some extra testing facilities to pcretest:
2063    
2064        \q<number>   in a data line sets the "match limit" value
2065        \Q<number>   in a data line sets the "match recursion limt" value
2066        -S <number>  sets the stack size, where <number> is in megabytes
2067    
2068        The -S option isn't available for Windows.
2069    
2070    
2071    Version 6.6 06-Feb-06
2072    ---------------------
2073    
2074     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2075        in pcreposix.h. I have copied the definition from pcre.h.
2076    
2077     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2078        because pcre.h is no longer a built file.
2079    
2080     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2081        not normally included in the compiled code.
2082    
2083    
2084  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
2085  ---------------------  ---------------------
2086    

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