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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.11 10-Oct-2010
5    ------------------------
7    1.  (*THEN) was not working properly if there were untried alternatives prior
8        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
9        backtracked to try for "b" instead of moving to the next alternative branch
10        at the same level (in this case, to look for "c"). The Perl documentation
11        is clear that when (*THEN) is backtracked onto, it goes to the "next
12        alternative in the innermost enclosing group".
14    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
15        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
16        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
17        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
18        (*THEN).
21    Version 8.10 25-Jun-2010
22    ------------------------
24    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
25        THEN.
27    2.  (*ACCEPT) was not working when inside an atomic group.
29    3.  Inside a character class, \B is treated as a literal by default, but
30        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
31        causes the error). The code is unchanged, but I tidied the documentation.
33    4.  Inside a character class, PCRE always treated \R and \X as literals,
34        whereas Perl faults them if its -w option is set. I have changed PCRE so
35        that it faults them when PCRE_EXTRA is set.
37    5.  Added support for \N, which always matches any character other than
38        newline. (It is the same as "." when PCRE_DOTALL is not set.)
40    6.  When compiling pcregrep with newer versions of gcc which may have
41        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
42        declared with attribute warn_unused_result" were given. Just casting the
43        result to (void) does not stop the warnings; a more elaborate fudge is
44        needed. I've used a macro to implement this.
46    7.  Minor change to pcretest.c to avoid a compiler warning.
48    8.  Added four artifical Unicode properties to help with an option to make
49        \s etc use properties (see next item). The new properties are: Xan
50        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
52    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
53        use Unicode properties. (*UCP) at the start of a pattern can be used to set
54        this option. Modified pcretest to add /W to test this facility. Added
55        REG_UCP to make it available via the POSIX interface.
57    10. Added --line-buffered to pcregrep.
59    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
60        studied, and the match started with a letter with a code point greater than
61        127 whose first byte was different to the first byte of the other case of
62        the letter, the other case of this starting letter was not recognized
63        (#976).
65    12. If a pattern that was studied started with a repeated Unicode property
66        test, for example, \p{Nd}+, there was the theoretical possibility of
67        setting up an incorrect bitmap of starting bytes, but fortunately it could
68        not have actually happened in practice until change 8 above was made (it
69        added property types that matched character-matching opcodes).
71    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
72        possible starting bytes for non-anchored patterns.
74    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
75        \R, and also a number of cases that involve Unicode properties, both
76        explicit and implicit when PCRE_UCP is set.
78    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
79        input, it could crash or give wrong results if characters with values
80        greater than 0xc0 were present in the subject string. (Detail: it assumed
81        UTF-8 input when processing these items.)
83    16. Added a lot of (int) casts to avoid compiler warnings in systems where
84        size_t is 64-bit (#991).
86    17. Added a check for running out of memory when PCRE is compiled with
87        --disable-stack-for-recursion (#990).
89    18. If the last data line in a file for pcretest does not have a newline on
90        the end, a newline was missing in the output.
92    19. The default pcre_chartables.c file recognizes only ASCII characters (values
93        less than 128) in its various bitmaps. However, there is a facility for
94        generating tables according to the current locale when PCRE is compiled. It
95        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
96        characters, are recognized by isspace() and therefore were getting set in
97        these tables, and indeed these tables seem to approximate to ISO 8859. This
98        caused a problem in UTF-8 mode when pcre_study() was used to create a list
99        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
100        which of course cannot start UTF-8 characters. I have changed the code so
101        that only real ASCII characters (less than 128) and the correct starting
102        bytes for UTF-8 encodings are set for characters greater than 127 when in
103        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
104        altogether.)
106    20. Added the /T option to pcretest so as to be able to run tests with non-
107        standard character tables, thus making it possible to include the tests
108        used for 19 above in the standard set of tests.
110    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
111        reference to a subpattern the other side of a comment that contains an
112        opening parenthesis caused either an internal compiling error, or a
113        reference to the wrong subpattern.
116    Version 8.02 19-Mar-2010
117    ------------------------
119    1.  The Unicode data tables have been updated to Unicode 5.2.0.
121    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
122        configured.
124    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
125        original author of that file, following a query about its status.
127    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
128        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
130    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
131        quantifier applied to a forward-referencing subroutine call, could compile
132        incorrect code or give the error "internal error: previously-checked
133        referenced subpattern not found".
135    6.  Both MS Visual Studio and Symbian OS have problems with initializing
136        variables to point to external functions. For these systems, therefore,
137        pcre_malloc etc. are now initialized to local functions that call the
138        relevant global functions.
140    7.  There were two entries missing in the vectors called coptable and poptable
141        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
142        I've fixed the data, and added a kludgy way of testing at compile time that
143        the lengths are correct (equal to the number of opcodes).
145    8.  Following on from 7, I added a similar kludge to check the length of the
146        eint vector in pcreposix.c.
148    9.  Error texts for pcre_compile() are held as one long string to avoid too
149        much relocation at load time. To find a text, the string is searched,
150        counting zeros. There was no check for running off the end of the string,
151        which could happen if a new error number was added without updating the
152        string.
154    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
156    11. \K was not working if it appeared in an atomic group or in a group that
157        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
158        \K is "not well defined" if used in an assertion. PCRE now accepts it if
159        the assertion is positive, but not if it is negative.
161    12. Change 11 fortuitously reduced the size of the stack frame used in the
162        "match()" function of pcre_exec.c by one pointer. Forthcoming
163        implementation of support for (*MARK) will need an extra pointer on the
164        stack; I have reserved it now, so that the stack frame size does not
165        decrease.
167    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
168        item in branch that calls a recursion is a subroutine call - as in the
169        second branch in the above example - was incorrectly given the compile-
170        time error "recursive call could loop indefinitely" because pcre_compile()
171        was not correctly checking the subroutine for matching a non-empty string.
173    14. The checks for overrunning compiling workspace could trigger after an
174        overrun had occurred. This is a "should never occur" error, but it can be
175        triggered by pathological patterns such as hundreds of nested parentheses.
176        The checks now trigger 100 bytes before the end of the workspace.
178    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
181    Version 8.01 19-Jan-2010
182    ------------------------
184    1.  If a pattern contained a conditional subpattern with only one branch (in
185        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
186        computed the wrong minimum data length (which is of course zero for such
187        subpatterns). This could cause incorrect "no match" results.
189    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
190        the pattern is reset in the first branch, pcre_compile() failed with
191        "internal error: code overflow at offset...". This happened only when
192        the reset was to the original external option setting. (An optimization
193        abstracts leading options settings into an external setting, which was the
194        cause of this.)
196    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
197        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
198        assertion pattern did not match (meaning that the assertion was true), it
199        was incorrectly treated as false if the SKIP had been reached during the
200        matching. This also applied to assertions used as conditions.
202    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
203        assertion subpattern, including such a pattern used as a condition,
204        unpredictable results occurred, instead of the error return
207    5.  The C++ GlobalReplace function was not working like Perl for the special
208        situation when an empty string is matched. It now does the fancy magic
209        stuff that is necessary.
211    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
212        removed. (These were left over from very, very early versions of PCRE.)
214    7.  Some cosmetic changes to the code to make life easier when compiling it
215        as part of something else:
217        (a) Change DEBUG to PCRE_DEBUG.
219        (b) In pcre_compile(), rename the member of the "branch_chain" structure
220            called "current" as "current_branch", to prevent a collision with the
221            Linux macro when compiled as a kernel module.
223        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
224            prevent a collision with the Linux macro when compiled as a kernel
225            module.
227    8.  In pcre_compile() there are some checks for integer overflows that used to
228        cast potentially large values to (double). This has been changed to that
229        when building, a check for int64_t is made, and if it is found, it is used
230        instead, thus avoiding the use of floating point arithmetic. (There is no
231        other use of FP in PCRE.) If int64_t is not found, the fallback is to
232        double.
234    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
235        2005 (difference between two addresses compared to an unsigned value).
237    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
238        custom one, because of the following reported problem in Windows:
240          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
241              under Win32.
242          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
243              therefore missing the function definition.
244          - The compiler thus generates a "C" signature for the test function.
245          - The linker fails to find the "C" function.
246          - PCRE fails to configure if asked to do so against libbz2.
248    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
249        messages were output:
251          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
252          rerunning libtoolize, to keep the correct libtool macros in-tree.
253          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
255        I have done both of these things.
257    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
258        most of the time, it *can* run out if it is given a pattern that contains a
259        runaway infinite recursion. I updated the discussion in the pcrestack man
260        page.
262    13. Now that we have gone to the x.xx style of version numbers, the minor
263        version may start with zero. Using 08 or 09 is a bad idea because users
264        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
265        interpreted as invalid octal numbers. I've updated the previous comment in
266        configure.ac, and also added a check that gives an error if 08 or 09 are
267        used.
269    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
270        causing partial matching to fail when the end of the subject matched \W
271        in a UTF-8 pattern where \W was quantified with a minimum of 3.
273    15. There were some discrepancies between the declarations in pcre_internal.h
274        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
275        their definitions. The declarations used "const uschar *" and the
276        definitions used USPTR. Even though USPTR is normally defined as "const
277        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
278        reported that: "This difference in casting confuses some C++ compilers, for
279        example, SunCC recognizes above declarations as different functions and
280        generates broken code for hbpcre." I have changed the declarations to use
281        USPTR.
283    16. GNU libtool is named differently on some systems. The autogen.sh script now
284        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
285        (FreeBSD).
287    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
288        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
289        comment: "Figure out how to create a longlong from a string: strtoll and
290        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
291        instance, but it only takes 2 args instead of 3!"
293    18. A subtle bug concerned with back references has been fixed by a change of
294        specification, with a corresponding code fix. A pattern such as
295        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
296        refers, was giving matches when it shouldn't. For example, xa=xaaa would
297        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
298        same bug. Such groups have to be quantified to be useful, or contained
299        inside another quantified group. (If there's no repetition, the reference
300        can never match.) The problem arises because, having left the group and
301        moved on to the rest of the pattern, a later failure that backtracks into
302        the group uses the captured value from the final iteration of the group
303        rather than the correct earlier one. I have fixed this in PCRE by forcing
304        any group that contains a reference to itself to be an atomic group; that
305        is, there cannot be any backtracking into it once it has completed. This is
306        similar to recursive and subroutine calls.
309    Version 8.00 19-Oct-09
310    ----------------------
312    1.  The table for translating pcre_compile() error codes into POSIX error codes
313        was out-of-date, and there was no check on the pcre_compile() error code
314        being within the table. This could lead to an OK return being given in
315        error.
317    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
318        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
319        in a Windows environment.
321    3.  The pcregrep --count option prints the count for each file even when it is
322        zero, as does GNU grep. However, pcregrep was also printing all files when
323        --files-with-matches was added. Now, when both options are given, it prints
324        counts only for those files that have at least one match. (GNU grep just
325        prints the file name in this circumstance, but including the count seems
326        more useful - otherwise, why use --count?) Also ensured that the
327        combination -clh just lists non-zero counts, with no names.
329    4.  The long form of the pcregrep -F option was incorrectly implemented as
330        --fixed_strings instead of --fixed-strings. This is an incompatible change,
331        but it seems right to fix it, and I didn't think it was worth preserving
332        the old behaviour.
334    5.  The command line items --regex=pattern and --regexp=pattern were not
335        recognized by pcregrep, which required --regex pattern or --regexp pattern
336        (with a space rather than an '='). The man page documented the '=' forms,
337        which are compatible with GNU grep; these now work.
339    6.  No libpcreposix.pc file was created for pkg-config; there was just
340        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
342    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
343        when UCP support is not needed, by modifying the Python script that
344        generates it from Unicode data files. This should not matter if the module
345        is correctly used as a library, but I received one complaint about 50K of
346        unwanted data. My guess is that the person linked everything into his
347        program rather than using a library. Anyway, it does no harm.
349    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
350        was a minimum greater than 1 for a wide character in a possessive
351        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
352        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
353        character. Chaos in the form of incorrect output or a compiling loop could
354        result.
356    9.  The restrictions on what a pattern can contain when partial matching is
357        requested for pcre_exec() have been removed. All patterns can now be
358        partially matched by this function. In addition, if there are at least two
359        slots in the offset vector, the offset of the earliest inspected character
360        for the match and the offset of the end of the subject are set in them when
361        PCRE_ERROR_PARTIAL is returned.
363    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
364        synonymous with PCRE_PARTIAL, for backwards compatibility, and
365        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
366        and may be more useful for multi-segment matching.
368    11. Partial matching with pcre_exec() is now more intuitive. A partial match
369        used to be given if ever the end of the subject was reached; now it is
370        given only if matching could not proceed because another character was
371        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
372        string "Z", which now yields "no match" instead of "partial match". In the
373        case of pcre_dfa_exec(), "no match" is given if every matching path for the
374        final character ended with (*FAIL).
376    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
377        if the pattern had a "must contain" character that was already found in the
378        earlier partial match, unless partial matching was again requested. For
379        example, with the pattern /dog.(body)?/, the "must contain" character is
380        "g". If the first part-match was for the string "dog", restarting with
381        "sbody" failed. This bug has been fixed.
383    13. The string returned by pcre_dfa_exec() after a partial match has been
384        changed so that it starts at the first inspected character rather than the
385        first character of the match. This makes a difference only if the pattern
386        starts with a lookbehind assertion or \b or \B (\K is not supported by
387        pcre_dfa_exec()). It's an incompatible change, but it makes the two
388        matching functions compatible, and I think it's the right thing to do.
390    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
391        so that the demonstration program is easily available in environments where
392        PCRE has not been installed from source.
394    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
395        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
396        library.
398    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
399        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
400        is not the first non-POSIX option to be added. Clearly some people find
401        these options useful.
403    17. If a caller to the POSIX matching function regexec() passes a non-zero
404        value for nmatch with a NULL value for pmatch, the value of
405        nmatch is forced to zero.
407    18. RunGrepTest did not have a test for the availability of the -u option of
408        the diff command, as RunTest does. It now checks in the same way as
409        RunTest, and also checks for the -b option.
411    19. If an odd number of negated classes containing just a single character
412        interposed, within parentheses, between a forward reference to a named
413        subpattern and the definition of the subpattern, compilation crashed with
414        an internal error, complaining that it could not find the referenced
415        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
416        [The bug was that it was starting one character too far in when skipping
417        over the character class, thus treating the ] as data rather than
418        terminating the class. This meant it could skip too much.]
420    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
421        /g option in pcretest when the pattern contains \K, which makes it possible
422        to have an empty string match not at the start, even when the pattern is
423        anchored. Updated pcretest and pcredemo to use this option.
425    21. If the maximum number of capturing subpatterns in a recursion was greater
426        than the maximum at the outer level, the higher number was returned, but
427        with unset values at the outer level. The correct (outer level) value is
428        now given.
430    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
431        PCRE did not set those parentheses (unlike Perl). I have now found a way to
432        make it do so. The string so far is captured, making this feature
433        compatible with Perl.
435    23. The tests have been re-organized, adding tests 11 and 12, to make it
436        possible to check the Perl 5.10 features against Perl 5.10.
438    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
439        pattern matches a fixed length string. PCRE did not allow this; now it
440        does. Neither allows recursion.
442    25. I finally figured out how to implement a request to provide the minimum
443        length of subject string that was needed in order to match a given pattern.
444        (It was back references and recursion that I had previously got hung up
445        on.) This code has now been added to pcre_study(); it finds a lower bound
446        to the length of subject needed. It is not necessarily the greatest lower
447        bound, but using it to avoid searching strings that are too short does give
448        some useful speed-ups. The value is available to calling programs via
449        pcre_fullinfo().
451    26. While implementing 25, I discovered to my embarrassment that pcretest had
452        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
453        study optimizations had never been tested with that matching function.
454        Oops. What is worse, even when it was passed study data, there was a bug in
455        pcre_dfa_exec() that meant it never actually used it. Double oops. There
456        were also very few tests of studied patterns with pcre_dfa_exec().
458    27. If (?| is used to create subpatterns with duplicate numbers, they are now
459        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
460        on the other side of the coin, they are no longer allowed to have different
461        names, because these cannot be distinguished in PCRE, and this has caused
462        confusion. (This is a difference from Perl.)
464    28. When duplicate subpattern names are present (necessarily with different
465        numbers, as required by 27 above), and a test is made by name in a
466        conditional pattern, either for a subpattern having been matched, or for
467        recursion in such a pattern, all the associated numbered subpatterns are
468        tested, and the overall condition is true if the condition is true for any
469        one of them. This is the way Perl works, and is also more like the way
470        testing by number works.
473    Version 7.9 11-Apr-09
474    ---------------------
476    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
477        (pcretest), all targets were linked against these libraries. This included
478        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
479        libraries. This caused unwanted dependencies to be created. This problem
480        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
481        pcretest is linked with readline.
483    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
484        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
485        moved outside it again, because FALSE and TRUE are already defined in AIX,
486        but BOOL is not.
488    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
489        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
491    4.  The pcregrep documentation said spaces were inserted as well as colons (or
492        hyphens) following file names and line numbers when outputting matching
493        lines. This is not true; no spaces are inserted. I have also clarified the
494        wording for the --colour (or --color) option.
496    5.  In pcregrep, when --colour was used with -o, the list of matching strings
497        was not coloured; this is different to GNU grep, so I have changed it to be
498        the same.
500    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
501        each matching line was coloured. Now it goes on to look for further matches
502        of any of the test patterns, which is the same behaviour as GNU grep.
504    7.  A pattern that could match an empty string could cause pcregrep to loop; it
505        doesn't make sense to accept an empty string match in pcregrep, so I have
506        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
507        seems to be how GNU grep behaves.
509    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
510        start or after a newline", because the conditional assertion was not being
511        correctly handled. The rule now is that both the assertion and what follows
512        in the first alternative must satisfy the test.
514    9.  If auto-callout was enabled in a pattern with a conditional group whose
515        condition was an assertion, PCRE could crash during matching, both with
516        pcre_exec() and pcre_dfa_exec().
518    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
519        used for matching.
521    11. Unicode property support in character classes was not working for
522        characters (bytes) greater than 127 when not in UTF-8 mode.
524    12. Added the -M command line option to pcretest.
526    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
528    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
530    16. Added comments and documentation about mis-use of no_arg in the C++
531        wrapper.
533    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
534        from Martin Jerabek that uses macro names for all relevant character and
535        string constants.
537    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
538        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
539        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
540        these, but not everybody uses configure.
542    19. A conditional group that had only one branch was not being correctly
543        recognized as an item that could match an empty string. This meant that an
544        enclosing group might also not be so recognized, causing infinite looping
545        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
546        with the subject "ab", where knowledge that the repeated group can match
547        nothing is needed in order to break the loop.
549    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
550        exec(), but without supplying a callout function, matching went wrong.
552    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
553        leak if the size of the offset vector was greater than 30. When the vector
554        is smaller, the saved offsets during recursion go onto a local stack
555        vector, but for larger vectors malloc() is used. It was failing to free
556        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
557        error, in fact).
559    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
560        heapframe that is used only when UTF-8 support is enabled. This caused no
561        problem, but was untidy.
563    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
564        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
565        included within another project.
567    24. Steven Van Ingelgem's patches to add more options to the CMake support,
568        slightly modified by me:
570          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
571              not building pcregrep.
573          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
574              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
576    25. Forward references, both numeric and by name, in patterns that made use of
577        duplicate group numbers, could behave incorrectly or give incorrect errors,
578        because when scanning forward to find the reference group, PCRE was not
579        taking into account the duplicate group numbers. A pattern such as
580        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
582    26. Changed a few more instances of "const unsigned char *" to USPTR, making
583        the feature of a custom pointer more persuasive (as requested by a user).
585    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
586        pcretest.c, inside #ifndefs, because it seems they are sometimes already
587        pre-defined.
589    28. Added support for (*UTF8) at the start of a pattern.
591    29. Arrange for flags added by the "release type" setting in CMake to be shown
592        in the configuration summary.
595    Version 7.8 05-Sep-08
596    ---------------------
598    1.  Replaced UCP searching code with optimized version as implemented for Ad
599        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
600        stage table and inline lookup instead of a function, giving speed ups of 2
601        to 5 times on some simple patterns that I tested. Permission was given to
602        distribute the MultiStage2.py script that generates the tables (it's not in
603        the tarball, but is in the Subversion repository).
605    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
606        scripts.
608    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
609        a group with a zero qualifier. The result of the study could be incorrect,
610        or the function might crash, depending on the pattern.
612    4.  Caseless matching was not working for non-ASCII characters in back
613        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
614        It now works when Unicode Property Support is available.
616    5.  In pcretest, an escape such as \x{de} in the data was always generating
617        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
618        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
619        truncation.
621    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
623    7.  Added two (int) casts to pcregrep when printing the difference of two
624        pointers, in case they are 64-bit values.
626    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
627        test 2 if it fails.
629    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
630        and a #define of that name to empty if it is not externally set. This is to
631        allow users of MSVC to set it if necessary.
633    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
634        the convenience functions in the pcre_get.c source file.
636    11. An option change at the start of a pattern that had top-level alternatives
637        could cause overwriting and/or a crash. This command provoked a crash in
638        some environments:
640          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
642        This potential security problem was recorded as CVE-2008-2371.
644    12. For a pattern where the match had to start at the beginning or immediately
645        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
646        pcre_dfa_exec() could read past the end of the passed subject if there was
647        no match. To help with detecting such bugs (e.g. with valgrind), I modified
648        pcretest so that it places the subject at the end of its malloc-ed buffer.
650    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
651        exec() might read past the end of the data buffer in UTF-8 mode.
653    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
654        the data contained the byte 0x85 as part of a UTF-8 character within its
655        first line. This applied both to normal and DFA matching.
657    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
658        /^[^d]*?$/8 failed to match "abc".
660    16. Added a missing copyright notice to pcrecpp_internal.h.
662    17. Make it more clear in the documentation that values returned from
663        pcre_exec() in ovector are byte offsets, not character counts.
665    18. Tidied a few places to stop certain compilers from issuing warnings.
667    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
668        supplied by Stefan Weber. I made a further small update for 7.8 because
669        there is a change of source arrangements: the pcre_searchfuncs.c module is
670        replaced by pcre_ucd.c.
673    Version 7.7 07-May-08
674    ---------------------
676    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
677        a string to a long long, pretend we don't even have a long long." This is
678        done by checking for the strtoq, strtoll, and _strtoi64 functions.
680    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
681        pre-7.6 versions, which defined a global no_arg variable instead of putting
682        it in the RE class. (See also #8 below.)
684    3.  Remove a line of dead code, identified by coverity and reported by Nuno
685        Lopes.
687    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
689        (1) The include/exclude patterns were being applied to the whole pathnames
690            of files, instead of just to the final components.
692        (2) If there was more than one level of directory, the subdirectories were
693            skipped unless they satisfied the include/exclude conditions. This is
694            inconsistent with GNU grep (and could even be seen as contrary to the
695            pcregrep specification - which I improved to make it absolutely clear).
696            The action now is always to scan all levels of directory, and just
697            apply the include/exclude patterns to regular files.
699    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
700        --exclude_dir in the tests to avoid scanning .svn directories.
702    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
703        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
704        doesn't support NULs in patterns.
706    7.  Added some missing "const"s to declarations of static tables in
707        pcre_compile.c and pcre_dfa_exec.c.
709    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
710        caused by fix #2  above. (Subsequently also a second patch to fix the
711        first patch. And a third patch - this was a messy problem.)
713    9.  Applied Craig's patch to remove the use of push_back().
715    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
716        matching function regexec().
718    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
719        which, however, unlike Perl's \g{...}, are subroutine calls, not back
720        references. PCRE supports relative numbers with this syntax (I don't think
721        Oniguruma does).
723    12. Previously, a group with a zero repeat such as (...){0} was completely
724        omitted from the compiled regex. However, this means that if the group
725        was called as a subroutine from elsewhere in the pattern, things went wrong
726        (an internal error was given). Such groups are now left in the compiled
727        pattern, with a new opcode that causes them to be skipped at execution
728        time.
730    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
731        to the way PCRE behaves:
733        (a) A lone ] character is dis-allowed (Perl treats it as data).
735        (b) A back reference to an unmatched subpattern matches an empty string
736            (Perl fails the current match path).
738        (c) A data ] in a character class must be notated as \] because if the
739            first data character in a class is ], it defines an empty class. (In
740            Perl it is not possible to have an empty class.) The empty class []
741            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
742            The negative empty class [^] matches any one character, independently
743            of the DOTALL setting.
745    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
746        non-existent subpattern following a character class starting with ']' and
747        containing () gave an internal compiling error instead of "reference to
748        non-existent subpattern". Fortunately, when the pattern did exist, the
749        compiled code was correct. (When scanning forwards to check for the
750        existencd of the subpattern, it was treating the data ']' as terminating
751        the class, so got the count wrong. When actually compiling, the reference
752        was subsequently set up correctly.)
754    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
755        it was being rejected as not supported by pcre_dfa_exec(), even though
756        other assertions are supported. I have made pcre_dfa_exec() support
757        (*FAIL).
759    16. The implementation of 13c above involved the invention of a new opcode,
760        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
761        cannot be changed at match time, I realized I could make a small
762        improvement to matching performance by compiling OP_ALLANY instead of
763        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
764        on the OP_ANY path.
766    17. Compiling pcretest on Windows with readline support failed without the
767        following two fixes: (1) Make the unistd.h include conditional on
768        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
770    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
771        ncurses library to be included for pcretest when ReadLine support is
772        requested, but also to allow for it to be overridden. This patch came from
773        Daniel Bergström.
775    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
776        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
777        any errors with the current Unicode tables. Thanks to Peter Kankowski for
778        spotting this.
781    Version 7.6 28-Jan-08
782    ---------------------
784    1.  A character class containing a very large number of characters with
785        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
786        overflow.
788    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
789        HAVE_LONG_LONG is not defined.
791    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
792        bring them up to date and include new features. This patch includes:
794        - Fixed PH's badly added libz and libbz2 support.
795        - Fixed a problem with static linking.
796        - Added pcredemo. [But later removed - see 7 below.]
797        - Fixed dftables problem and added an option.
798        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
799            HAVE_LONG_LONG.
800        - Added readline support for pcretest.
801        - Added an listing of the option settings after cmake has run.
803    4.  A user submitted a patch to Makefile that makes it easy to create
804        "pcre.dll" under mingw when using Configure/Make. I added stuff to
805        Makefile.am that cause it to include this special target, without
806        affecting anything else. Note that the same mingw target plus all
807        the other distribution libraries and programs are now supported
808        when configuring with CMake (see 6 below) instead of with
809        Configure/Make.
811    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
812        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
813        exported in the Windows port". It has not yet been confirmed that the patch
814        solves the problem, but it does no harm.
816    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
817        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
818        with CMake, and also correct the comment about stack recursion.
820    7.  Remove the automatic building of pcredemo from the ./configure system and
821        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
822        of a program that users should build themselves after PCRE is installed, so
823        building it automatically is not really right. What is more, it gave
824        trouble in some build environments.
826    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
829    Version 7.5 10-Jan-08
830    ---------------------
832    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
833        values in parens when parsing an RE using the C++ wrapper."
835    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
836        Characters greater than 255 were excluded from the class instead of being
837        included.
839    3.  The same bug as (2) above applied to negated POSIX classes such as
840        [:^space:].
842    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
843        defined or documented. It seems to have been a typo for PCRE_STATIC, so
844        I have changed it.
846    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
847        first named subpattern) and a construct such as (?&a) would reference the
848        first named subpattern whose name started with "a" (in other words, the
849        length check was missing). Both these problems are fixed. "Subpattern name
850        expected" is now given for (?&) (a zero-length name), and this patch also
851        makes it give the same error for \k'' (previously it complained that that
852        was a reference to a non-existent subpattern).
854    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
855        this is right because (?- can be followed by option settings as well as by
856        digits. I have, however, made the messages clearer.
858    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
859        than the number used in the conditional) now cause a compile-time error.
860        This is actually not compatible with Perl, which accepts such patterns, but
861        treats the conditional as always being FALSE (as PCRE used to), but it
862        seems to me that giving a diagnostic is better.
864    8.  Change "alphameric" to the more common word "alphanumeric" in comments
865        and messages.
867    9.  Fix two occurrences of "backslash" in comments that should have been
868        "backspace".
870    10. Remove two redundant lines of code that can never be obeyed (their function
871        was moved elsewhere).
873    11. The program that makes PCRE's Unicode character property table had a bug
874        which caused it to generate incorrect table entries for sequences of
875        characters that have the same character type, but are in different scripts.
876        It amalgamated them into a single range, with the script of the first of
877        them. In other words, some characters were in the wrong script. There were
878        thirteen such cases, affecting characters in the following ranges:
880          U+002b0 - U+002c1
881          U+0060c - U+0060d
882          U+0061e - U+00612
883          U+0064b - U+0065e
884          U+0074d - U+0076d
885          U+01800 - U+01805
886          U+01d00 - U+01d77
887          U+01d9b - U+01dbf
888          U+0200b - U+0200f
889          U+030fc - U+030fe
890          U+03260 - U+0327f
891          U+0fb46 - U+0fbb1
892          U+10450 - U+1049d
894    12. The -o option (show only the matching part of a line) for pcregrep was not
895        compatible with GNU grep in that, if there was more than one match in a
896        line, it showed only the first of them. It now behaves in the same way as
897        GNU grep.
899    13. If the -o and -v options were combined for pcregrep, it printed a blank
900        line for every non-matching line. GNU grep prints nothing, and pcregrep now
901        does the same. The return code can be used to tell if there were any
902        non-matching lines.
904    14. Added --file-offsets and --line-offsets to pcregrep.
906    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
907        infinitely looping recursion. The bug was that positive lookaheads were not
908        being skipped when checking for a possible empty match (negative lookaheads
909        and both kinds of lookbehind were skipped).
911    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
912        inclusion of <windows.h> to before rather than after the definition of
913        INVALID_FILE_ATTRIBUTES (patch from David Byron).
915    17. Specifying a possessive quantifier with a specific limit for a Unicode
916        character property caused pcre_compile() to compile bad code, which led at
917        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
918        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
919        caused the error; without that there was no problem.
921    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
923    19. Added --enable-pcretest-libreadline.
925    20. In pcrecpp.cc, the variable 'count' was incremented twice in
926        RE::GlobalReplace(). As a result, the number of replacements returned was
927        double what it should be. I removed one of the increments, but Craig sent a
928        later patch that removed the other one (the right fix) and added unit tests
929        that check the return values (which was not done before).
931    21. Several CMake things:
933        (1) Arranged that, when cmake is used on Unix, the libraries end up with
934            the names libpcre and libpcreposix, not just pcre and pcreposix.
936        (2) The above change means that pcretest and pcregrep are now correctly
937            linked with the newly-built libraries, not previously installed ones.
941    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
942        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
943        UTF-8 newline character). The key issue is that the pattern starts .*;
944        this means that the match must be either at the beginning, or after a
945        newline. The bug was in the code for advancing after a failed match and
946        checking that the new position followed a newline. It was not taking
947        account of UTF-8 characters correctly.
949    23. PCRE was behaving differently from Perl in the way it recognized POSIX
950        character classes. PCRE was not treating the sequence [:...:] as a
951        character class unless the ... were all letters. Perl, however, seems to
952        allow any characters between [: and :], though of course it rejects as
953        unknown any "names" that contain non-letters, because all the known class
954        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
955        for example, whereas PCRE did not - it did not recognize a POSIX character
956        class. This seemed a bit dangerous, so the code has been changed to be
957        closer to Perl. The behaviour is not identical to Perl, because PCRE will
958        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
959        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
960        Perl does, and where it didn't before.
962    24. Rewrite so as to remove the single use of %n from pcregrep because in some
963        Windows environments %n is disabled by default.
966    Version 7.4 21-Sep-07
967    ---------------------
969    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
970        means that a class such as [\s] counted as "explicit reference to CR or
971        LF". That isn't really right - the whole point of the change was to try to
972        help when there was an actual mention of one of the two characters. So now
973        the change happens only if \r or \n (or a literal CR or LF) character is
974        encountered.
976    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
977        of both had grown to the point where there were only 3 bits left.
978        Fortunately, there was spare space in the data structure, and so I have
979        moved the internal flags into a new 16-bit field to free up more option
980        bits.
982    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
983        but did not set the internal JCHANGED flag - either of these is enough to
984        control the way the "get" function works - but the PCRE_INFO_JCHANGED
985        facility is supposed to tell if (?J) was ever used, so now (?J) at the
986        start sets both bits.
988    4.  Added options (at build time, compile time, exec time) to change \R from
989        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
991    5.  doc/pcresyntax.html was missing from the distribution.
993    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
994        compatibility, even though it is no longer used.
996    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
997        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
998        windows.h file is present (where different names are used). [This was
999        reversed later after testing - see 16 below.]
1001    8.  Changed all #include <config.h> to #include "config.h". There were also
1002        some further <pcre.h> cases that I changed to "pcre.h".
1004    9.  When pcregrep was used with the --colour option, it missed the line ending
1005        sequence off the lines that it output.
1007    10. It was pointed out to me that arrays of string pointers cause lots of
1008        relocations when a shared library is dynamically loaded. A technique of
1009        using a single long string with a table of offsets can drastically reduce
1010        these. I have refactored PCRE in four places to do this. The result is
1011        dramatic:
1013          Originally:                          290
1014          After changing UCP table:            187
1015          After changing error message table:   43
1016          After changing table of "verbs"       36
1017          After changing table of Posix names   22
1019        Thanks to the folks working on Gregex for glib for this insight.
1021    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1022        unicode-properties was also set.
1024    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1026    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1027        checked only for CRLF.
1029    14. Added casts to pcretest.c to avoid compiler warnings.
1031    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1033    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1034        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1035        entirely. This removes changes made in 7 above.
1037    17. The CMake files have been updated, and there is now more information about
1038        building with CMake in the NON-UNIX-USE document.
1041    Version 7.3 28-Aug-07
1042    ---------------------
1044     1. In the rejigging of the build system that eventually resulted in 7.1, the
1045        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1046        brackets there is not right, since it causes compilers to look for an
1047        installed pcre.h, not the version that is in the source that is being
1048        compiled (which of course may be different). I have changed it back to:
1050          #include "pcre.h"
1052        I have a vague recollection that the change was concerned with compiling in
1053        different directories, but in the new build system, that is taken care of
1054        by the VPATH setting the Makefile.
1056     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1057        when the subject happened to end in the byte 0x85 (e.g. if the last
1058        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1059        characters but of course it shouldn't be taken as a newline when it is part
1060        of another character. The bug was that, for an unlimited repeat of . in
1061        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1062        characters when looking for a newline.
1064     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1066     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1067        in debug output.
1069     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1070        long printing in the pcrecpp unittest when running under MinGW.
1072     6. ESC_K was left out of the EBCDIC table.
1074     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1075        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1076        limit also applies to "virtual nesting" when a pattern is recursive, and in
1077        this case 1000 isn't so big. I have been able to remove this limit at the
1078        expense of backing off one optimization in certain circumstances. Normally,
1079        when pcre_exec() would call its internal match() function recursively and
1080        immediately return the result unconditionally, it uses a "tail recursion"
1081        feature to save stack. However, when a subpattern that can match an empty
1082        string has an unlimited repetition quantifier, it no longer makes this
1083        optimization. That gives it a stack frame in which to save the data for
1084        checking that an empty string has been matched. Previously this was taken
1085        from the 1000-entry workspace that had been reserved. So now there is no
1086        explicit limit, but more stack is used.
1088     8. Applied Daniel's patches to solve problems with the import/export magic
1089        syntax that is required for Windows, and which was going wrong for the
1090        pcreposix and pcrecpp parts of the library. These were overlooked when this
1091        problem was solved for the main library.
1093     9. There were some crude static tests to avoid integer overflow when computing
1094        the size of patterns that contain repeated groups with explicit upper
1095        limits. As the maximum quantifier is 65535, the maximum group length was
1096        set at 30,000 so that the product of these two numbers did not overflow a
1097        32-bit integer. However, it turns out that people want to use groups that
1098        are longer than 30,000 bytes (though not repeat them that many times).
1099        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1100        made it possible to implement the integer overflow checks in a much more
1101        dynamic way, which I have now done. The artificial limitation on group
1102        length has been removed - we now have only the limit on the total length of
1103        the compiled pattern, which depends on the LINK_SIZE setting.
1105    10. Fixed a bug in the documentation for get/copy named substring when
1106        duplicate names are permitted. If none of the named substrings are set, the
1107        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1108        empty string.
1110    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1111        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1112        because the ] is interpreted as the first data character and the
1113        terminating ] is not found. PCRE has been made compatible with Perl in this
1114        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1115        cause memory overwriting.
1117    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1118        string has been matched (to stop an infinite loop). It was not recognizing
1119        a conditional subpattern that could match an empty string if that
1120        subpattern was within another subpattern. For example, it looped when
1121        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1122        condition was not nested. This bug has been fixed.
1124    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1125        past the start of the subject in the presence of bytes with the top bit
1126        set, for example "\x8aBCD".
1128    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1129        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1131    14. Optimized (?!) to (*FAIL).
1133    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1134        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1135        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1136        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1137        does: it's just the validity check that is more restrictive.
1139    16. Inserted checks for integer overflows during escape sequence (backslash)
1140        processing, and also fixed erroneous offset values for syntax errors during
1141        backslash processing.
1143    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1144        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1146    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1147        caused an overrun.
1149    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1150        something other than just ASCII characters) inside a group that had an
1151        unlimited repeat caused a loop at compile time (while checking to see
1152        whether the group could match an empty string).
1154    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1155        [\P{Any}] did so. (Error in the code for printing property names.)
1157    21. An orphan \E inside a character class could cause a crash.
1159    22. A repeated capturing bracket such as (A)? could cause a wild memory
1160        reference during compilation.
1162    23. There are several functions in pcre_compile() that scan along a compiled
1163        expression for various reasons (e.g. to see if it's fixed length for look
1164        behind). There were bugs in these functions when a repeated \p or \P was
1165        present in the pattern. These operators have additional parameters compared
1166        with \d, etc, and these were not being taken into account when moving along
1167        the compiled data. Specifically:
1169        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1170            length.
1172        (b) An item such as \pL+ within a repeated group could cause crashes or
1173            loops.
1175        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1176            "reference to non-existent subpattern" error.
1178        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1180    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1181        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1183    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1185    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1186        character were causing crashes (broken optimization).
1188    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1189        \p or \P) caused a compile-time loop.
1191    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1192        break. For example, the unstudied pattern [\r\n]A does not match the string
1193        "\r\nA" because change 7.0/46 below moves the current point on by two
1194        characters after failing to match at the start. However, the pattern \nA
1195        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1196        the same is true. There doesn't seem any very clean way out of this, but
1197        what I have chosen to do makes the common cases work: PCRE now takes note
1198        of whether there can be an explicit match for \r or \n anywhere in the
1199        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1200        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1201        pattern has explicit CR or LF references.
1203    29. Added (*CR) etc for changing newline setting at start of pattern.
1206    Version 7.2 19-Jun-07
1207    ---------------------
1209     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1210        which is apparently normally available under Windows.
1212     2. Re-jig the pcregrep tests with different newline settings in an attempt
1213        to make them independent of the local environment's newline setting.
1215     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1217     4. Some of the "internals" tests were previously cut out when the link size
1218        was not 2, because the output contained actual offsets. The recent new
1219        "Z" feature of pcretest means that these can be cut out, making the tests
1220        usable with all link sizes.
1222     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1223        stack recursion. This gives a massive performance boost under BSD, but just
1224        a small improvement under Linux. However, it saves one field in the frame
1225        in all cases.
1227     6. Added more features from the forthcoming Perl 5.10:
1229        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1230            recursion call. It refers to the nth most recently opened parentheses.
1232        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1233            to be opened parentheses.
1235        (c) Conditions that refer to capturing parentheses can be specified
1236            relatively, for example, (?(-2)... or (?(+3)...
1238        (d) \K resets the start of the current match so that everything before
1239            is not part of it.
1241        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1243        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1244            reference syntax.
1246        (g) (?| introduces a group in which the numbering of parentheses in each
1247            alternative starts with the same number.
1249        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1251     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1254     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1255        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1256        for detecting groups that can match an empty string.
1258     9. A pattern with a very large number of alternatives (more than several
1259        hundred) was running out of internal workspace during the pre-compile
1260        phase, where pcre_compile() figures out how much memory will be needed. A
1261        bit of new cunning has reduced the workspace needed for groups with
1262        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1263        workspace instead of running out of the 4096 that are available.
1265    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1267    11. Applied patch from Google to remove an optimization that didn't quite work.
1268        The report of the bug said:
1270          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1271          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1272          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1274    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1275        it matched the wrong number of bytes.
1278    Version 7.1 24-Apr-07
1279    ---------------------
1281     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1282        that is more "standard", making use of automake and other Autotools. There
1283        is some re-arrangement of the files and adjustment of comments consequent
1284        on this.
1286     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1287        for recursive directory scanning broke on some systems because the files
1288        are not scanned in any specific order and on different systems the order
1289        was different. A call to "sort" has been inserted into RunGrepTest for the
1290        approprate test as a short-term fix. In the longer term there may be an
1291        alternative.
1293     3. I had an email from Eric Raymond about problems translating some of PCRE's
1294        man pages to HTML (despite the fact that I distribute HTML pages, some
1295        people do their own conversions for various reasons). The problems
1296        concerned the use of low-level troff macros .br and .in. I have therefore
1297        removed all such uses from the man pages (some were redundant, some could
1298        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1299        HTML has been updated to handle .nf/.fi and to complain if it encounters
1300        .br or .in.
1302     4. Updated comments in configure.ac that get placed in config.h.in and also
1303        arranged for config.h to be included in the distribution, with the name
1304        config.h.generic, for the benefit of those who have to compile without
1305        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1307     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1308        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1309        makevp.bat for the current PCRE, using the additional files
1310        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1312     6. A Windows user reported a minor discrepancy with test 2, which turned out
1313        to be caused by a trailing space on an input line that had got lost in his
1314        copy. The trailing space was an accident, so I've just removed it.
1316     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1317        that is needed.
1319     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1320        as "const" (a) because they are and (b) because it helps the PHP
1321        maintainers who have recently made a script to detect big data structures
1322        in the php code that should be moved to the .rodata section. I remembered
1323        to update Builducptable as well, so it won't revert if ucptable.h is ever
1324        re-created.
1326     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1327        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1328        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1329        support is not required. This saves 1.5-2K of code, which is important in
1330        some applications.
1332        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1333        so as not to refer to the tables, even though these functions will never be
1334        called when UTF-8 support is disabled. Otherwise there are problems with a
1335        shared library.
1337    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1339        (a) It was defining its arguments as char * instead of void *.
1341        (b) It was assuming that all moves were upwards in memory; this was true
1342            a long time ago when I wrote it, but is no longer the case.
1344        The emulated memove() is provided for those environments that have neither
1345        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1346        is clearly not the case, as these two bugs were recently reported.
1348    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1349        and Detrail to create the HTML documentation, the .txt form of the man
1350        pages, and it removes trailing spaces from listed files. It also creates
1351        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1352        case, it wraps all the #defines with #ifndefs. This script should be run
1353        before "make dist".
1355    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1356        with Unicode property support.
1358        (a) For a maximizing quantifier, if the two different cases of the
1359            character were of different lengths in their UTF-8 codings (there are
1360            some cases like this - I found 11), and the matching function had to
1361            back up over a mixture of the two cases, it incorrectly assumed they
1362            were both the same length.
1364        (b) When PCRE was configured to use the heap rather than the stack for
1365            recursion during matching, it was not correctly preserving the data for
1366            the other case of a UTF-8 character when checking ahead for a match
1367            while processing a minimizing repeat. If the check also involved
1368            matching a wide character, but failed, corruption could cause an
1369            erroneous result when trying to check for a repeat of the original
1370            character.
1372    13. Some tidying changes to the testing mechanism:
1374        (a) The RunTest script now detects the internal link size and whether there
1375            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1376            values substituted by "configure". (The RunGrepTest script already did
1377            this for UTF-8.) The configure.ac script no longer substitutes the
1378            relevant variables.
1380        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1381            with length and offset values. This means that the output is different
1382            for different internal link sizes. Test 2 is skipped for link sizes
1383            other than 2 because of this, bypassing the problem. Unfortunately,
1384            there was also a test in test 3 (the locale tests) that used /B and
1385            failed for link sizes other than 2. Rather than cut the whole test out,
1386            I have added a new /Z option to pcretest that replaces the length and
1387            offset values with spaces. This is now used to make test 3 independent
1388            of link size. (Test 2 will be tidied up later.)
1390    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1391        segmentation fault instead of returning the appropriate error message.
1393    15. In multiline mode when the newline sequence was set to "any", the pattern
1394        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1395        This doesn't seem right; it now treats the CRLF combination as the line
1396        ending, and so does not match in that case. It's only a pattern such as ^$
1397        that would hit this one: something like ^ABC$ would have failed after \r
1398        and then tried again after \r\n.
1400    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1401        in an attempt to make files that differ only in their line terminators
1402        compare equal. This works on Linux.
1404    17. Under certain error circumstances pcregrep might try to free random memory
1405        as it exited. This is now fixed, thanks to valgrind.
1407    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1408        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1409        was because its rules for how to advance for /g after matching an empty
1410        string at the end of a line did not allow for this case. They now check for
1411        it specially.
1413    20. pcretest is supposed to handle patterns and data of any length, by
1414        extending its buffers when necessary. It was getting this wrong when the
1415        buffer for a data line had to be extended.
1417    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1418        CRLF as a newline sequence.
1420    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1421        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1422        I have nevertheless tidied it up.
1424    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1426    24. Added a man page for pcre-config.
1429    Version 7.0 19-Dec-06
1430    ---------------------
1432     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1433        moving to gcc 4.1.1.
1435     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1436        sys/time.h, which is documented as needed for this function. It doesn't
1437        seem to matter on Linux, but it showed up on some releases of OS X.
1439     3. It seems that there are systems where bytes whose values are greater than
1440        127 match isprint() in the "C" locale. The "C" locale should be the
1441        default when a C program starts up. In most systems, only ASCII printing
1442        characters match isprint(). This difference caused the output from pcretest
1443        to vary, making some of the tests fail. I have changed pcretest so that:
1445        (a) When it is outputting text in the compiled version of a pattern, bytes
1446            other than 32-126 are always shown as hex escapes.
1448        (b) When it is outputting text that is a matched part of a subject string,
1449            it does the same, unless a different locale has been set for the match
1450            (using the /L modifier). In this case, it uses isprint() to decide.
1452     4. Fixed a major bug that caused incorrect computation of the amount of memory
1453        required for a compiled pattern when options that changed within the
1454        pattern affected the logic of the preliminary scan that determines the
1455        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1456        that the computed length was too small. The symptoms of this bug were
1457        either the PCRE error "internal error: code overflow" from pcre_compile(),
1458        or a glibc crash with a message such as "pcretest: free(): invalid next
1459        size (fast)". Examples of patterns that provoked this bug (shown in
1460        pcretest format) are:
1462          /(?-x: )/x
1463          /(?x)(?-x: \s*#\s*)/
1464          /((?i)[\x{c0}])/8
1465          /(?i:[\x{c0}])/8
1467        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1468        is now done differently.
1470     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1471        wrapper classes; (b) implement a new function in the C++ scanner that is
1472        more efficient than the old way of doing things because it avoids levels of
1473        recursion in the regex matching; (c) add a paragraph to the documentation
1474        for the FullMatch() function.
1476     6. The escape sequence \n was being treated as whatever was defined as
1477        "newline". Not only was this contrary to the documentation, which states
1478        that \n is character 10 (hex 0A), but it also went horribly wrong when
1479        "newline" was defined as CRLF. This has been fixed.
1481     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1482        was being set to -1 for the "end of line" case (supposedly a value that no
1483        character can have). Though this value is never used (the check for end of
1484        line is "zero bytes in current character"), it caused compiler complaints.
1485        I've changed it to 0xffffffff.
1487     8. In pcre_version.c, the version string was being built by a sequence of
1488        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1489        string (as it is for production releases) called a macro with an empty
1490        argument. The C standard says the result of this is undefined. The gcc
1491        compiler treats it as an empty string (which was what was wanted) but it is
1492        reported that Visual C gives an error. The source has been hacked around to
1493        avoid this problem.
1495     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1496        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1497        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1498        of them did).
1500    10. Originally, pcretest opened its input and output without "b"; then I was
1501        told that "b" was needed in some environments, so it was added for release
1502        5.0 to both the input and output. (It makes no difference on Unix-like
1503        systems.) Later I was told that it is wrong for the input on Windows. I've
1504        now abstracted the modes into two macros, to make it easier to fiddle with
1505        them, and removed "b" from the input mode under Windows.
1507    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1509    12. Added -help and --help to pcretest as an official way of being reminded
1510        of the options.
1512    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1513        and pcrecpp.cc because they annoy compilers at high warning levels.
1515    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1517    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1518        scripts are not C programs :-) and which was not noticed because it works
1519        on Linux.
1521    16. pcretest is supposed to handle any length of pattern and data line (as one
1522        line or as a continued sequence of lines) by extending its input buffer if
1523        necessary. This feature was broken for very long pattern lines, leading to
1524        a string of junk being passed to pcre_compile() if the pattern was longer
1525        than about 50K.
1527    17. I have done a major re-factoring of the way pcre_compile() computes the
1528        amount of memory needed for a compiled pattern. Previously, there was code
1529        that made a preliminary scan of the pattern in order to do this. That was
1530        OK when PCRE was new, but as the facilities have expanded, it has become
1531        harder and harder to keep it in step with the real compile phase, and there
1532        have been a number of bugs (see for example, 4 above). I have now found a
1533        cunning way of running the real compile function in a "fake" mode that
1534        enables it to compute how much memory it would need, while actually only
1535        ever using a few hundred bytes of working memory and without too many
1536        tests of the mode. This should make future maintenance and development
1537        easier. A side effect of this work is that the limit of 200 on the nesting
1538        depth of parentheses has been removed (though this was never a serious
1539        limitation, I suspect). However, there is a downside: pcre_compile() now
1540        runs more slowly than before (30% or more, depending on the pattern). I
1541        hope this isn't a big issue. There is no effect on runtime performance.
1543    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1544        newline (only possible for the last line of a file) and it was a
1545        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1547    19. Added additional timing features to pcretest. (1) The -tm option now times
1548        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1549        separate command line item, by a number that specifies the number of
1550        repeats to use when timing. The default is 50000; this gives better
1551        precision, but takes uncomfortably long for very large patterns.
1553    20. Extended pcre_study() to be more clever in cases where a branch of a
1554        subpattern has no definite first character. For example, (a*|b*)[cd] would
1555        previously give no result from pcre_study(). Now it recognizes that the
1556        first character must be a, b, c, or d.
1558    21. There was an incorrect error "recursive call could loop indefinitely" if
1559        a subpattern (or the entire pattern) that was being tested for matching an
1560        empty string contained only one non-empty item after a nested subpattern.
1561        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1562        incorrectly, because the \d was being skipped in the check.
1564    22. The pcretest program now has a new pattern option /B and a command line
1565        option -b, which is equivalent to adding /B to every pattern. This causes
1566        it to show the compiled bytecode, without the additional information that
1567        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1568        is the same as /B/I).
1570    23. A new optimization is now able automatically to treat some sequences such
1571        as a*b as a*+b. More specifically, if something simple (such as a character
1572        or a simple class like \d) has an unlimited quantifier, and is followed by
1573        something that cannot possibly match the quantified thing, the quantifier
1574        is automatically "possessified".
1576    24. A recursive reference to a subpattern whose number was greater than 39
1577        went wrong under certain circumstances in UTF-8 mode. This bug could also
1578        have affected the operation of pcre_study().
1580    25. Realized that a little bit of performance could be had by replacing
1581        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1583    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1585    27. Possessive quantifiers such as a++ were previously implemented by turning
1586        them into atomic groups such as ($>a+). Now they have their own opcodes,
1587        which improves performance. This includes the automatically created ones
1588        from 23 above.
1590    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1591        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1592        the first matched character to be a colon. This applied both to named and
1593        numbered groups.
1595    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1597    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1598        building PCRE on Windows easier, so I have included it in the distribution.
1600    31. There is now a check in pcretest against a ridiculously large number being
1601        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1602        loop, the loop is abandoned.
1604    32. Forward references to subpatterns in conditions such as (?(2)...) where
1605        subpattern 2 is defined later cause pcre_compile() to search forwards in
1606        the pattern for the relevant set of parentheses. This search went wrong
1607        when there were unescaped parentheses in a character class, parentheses
1608        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1610    33. "Subroutine" calls and backreferences were previously restricted to
1611        referencing subpatterns earlier in the regex. This restriction has now
1612        been removed.
1614    34. Added a number of extra features that are going to be in Perl 5.10. On the
1615        whole, these are just syntactic alternatives for features that PCRE had
1616        previously implemented using the Python syntax or my own invention. The
1617        other formats are all retained for compatibility.
1619        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1620            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1621            also .NET compatible.
1623        (b) A recursion or subroutine call to a named group can now be defined as
1624            (?&name) as well as (?P>name).
1626        (c) A backreference to a named group can now be defined as \k<name> or
1627            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1628            5.10, are also .NET compatible.
1630        (d) A conditional reference to a named group can now use the syntax
1631            (?(<name>) or (?('name') as well as (?(name).
1633        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1634            groups (named and numbered) that are never evaluated inline, but can be
1635            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1636            is always false. There may be only one alternative in such a group.
1638        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1639            as the simple (?(R). The condition is true only if the most recent
1640            recursion is that of the given number or name. It does not search out
1641            through the entire recursion stack.
1643        (g) The escape \gN or \g{N} has been added, where N is a positive or
1644            negative number, specifying an absolute or relative reference.
1646    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1647        some "unreachable code" warnings.
1649    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1650        things, this adds five new scripts.
1652    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1653        There were also incompatibilities regarding the handling of \Q..\E inside
1654        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1655        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1657    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1658        matches an empty string, and forcibly breaks the loop. There were bugs in
1659        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1660        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1661        separate and independent bugs (that affected different cases) have been
1662        fixed.
1664    39. Refactored the code to abolish the use of different opcodes for small
1665        capturing bracket numbers. This is a tidy that I avoided doing when I
1666        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1667        The new approach is not only tidier, it makes it possible to reduce the
1668        memory needed to fix the previous bug (38).
1670    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1671        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1672        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1673        mode.
1675    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1676        report.
1678    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1679        copy construction and assignment in the C++ wrapper.
1681    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1682        couple of bugs that could have given wrong results in the "--newline=crlf"
1683        case.
1685    44. Added a number of casts and did some reorganization of signed/unsigned int
1686        variables following suggestions from Dair Grant. Also renamed the variable
1687        "this" as "item" because it is a C++ keyword.
1689    45. Arranged for dftables to add
1691          #include "pcre_internal.h"
1693        to pcre_chartables.c because without it, gcc 4.x may remove the array
1694        definition from the final binary if PCRE is built into a static library and
1695        dead code stripping is activated.
1697    46. For an unanchored pattern, if a match attempt fails at the start of a
1698        newline sequence, and the newline setting is CRLF or ANY, and the next two
1699        characters are CRLF, advance by two characters instead of one.
1702    Version 6.7 04-Jul-06
1703    ---------------------
1705     1. In order to handle tests when input lines are enormously long, pcretest has
1706        been re-factored so that it automatically extends its buffers when
1707        necessary. The code is crude, but this _is_ just a test program. The
1708        default size has been increased from 32K to 50K.
1710     2. The code in pcre_study() was using the value of the re argument before
1711        testing it for NULL. (Of course, in any sensible call of the function, it
1712        won't be NULL.)
1714     3. The memmove() emulation function in pcre_internal.h, which is used on
1715        systems that lack both memmove() and bcopy() - that is, hardly ever -
1716        was missing a "static" storage class specifier.
1718     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1719        containing an extended class (one that cannot be represented by a bitmap
1720        because it contains high-valued characters or Unicode property items, e.g.
1721        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1722        pattern, but PCRE should not loop if you do not (it no longer does).
1723        [Detail: two cases were found: (a) a repeated subpattern containing an
1724        extended class; (b) a recursive reference to a subpattern that followed a
1725        previous extended class. It wasn't skipping over the extended class
1726        correctly when UTF-8 mode was not set.]
1728     5. A negated single-character class was not being recognized as fixed-length
1729        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1730        compile error "lookbehind assertion is not fixed length".
1732     6. The RunPerlTest auxiliary script was showing an unexpected difference
1733        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1734        write a Perl script that can interpret lines of an input file either as
1735        byte characters or as UTF-8, which is what "perltest" was being required to
1736        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1737        can't do is switch easily at run time between having the "use utf8;" pragma
1738        or not. In the end, I fudged it by using the RunPerlTest script to insert
1739        "use utf8;" explicitly for the UTF-8 tests.
1741     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1742        the end of the subject string, contrary to the documentation and to what
1743        Perl does. This was true of both matching functions. Now it matches only at
1744        the start of the subject and immediately after *internal* newlines.
1746     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1747        a pointer to an int instead of a pointer to an unsigned long int. This
1748        caused problems on 64-bit systems.
1750     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1751        instance of the 'standard' template library not being so standard".
1753    10. There was no check on the number of named subpatterns nor the maximum
1754        length of a subpattern name. The product of these values is used to compute
1755        the size of the memory block for a compiled pattern. By supplying a very
1756        long subpattern name and a large number of named subpatterns, the size
1757        computation could be caused to overflow. This is now prevented by limiting
1758        the length of names to 32 characters, and the number of named subpatterns
1759        to 10,000.
1761    11. Subpatterns that are repeated with specific counts have to be replicated in
1762        the compiled pattern. The size of memory for this was computed from the
1763        length of the subpattern and the repeat count. The latter is limited to
1764        65535, but there was no limit on the former, meaning that integer overflow
1765        could in principle occur. The compiled length of a repeated subpattern is
1766        now limited to 30,000 bytes in order to prevent this.
1768    12. Added the optional facility to have named substrings with the same name.
1770    13. Added the ability to use a named substring as a condition, using the
1771        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1772        are numbers (not recommended). Forward references are permitted.
1774    14. Added forward references in named backreferences (if you see what I mean).
1776    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1777        pattern could run off the end of the subject. For example, the pattern
1778        "(?s)(.{1,5})"8 did this with the subject "ab".
1780    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1781        PCRE_CASELESS was set when matching characters that were quantified with ?
1782        or *.
1784    17. A character class other than a single negated character that had a minimum
1785        but no maximum quantifier - for example [ab]{6,} - was not handled
1786        correctly by pce_dfa_exec(). It would match only one character.
1788    18. A valid (though odd) pattern that looked like a POSIX character
1789        class but used an invalid character after [ (for example [[,abc,]]) caused
1790        pcre_compile() to give the error "Failed: internal error: code overflow" or
1791        in some cases to crash with a glibc free() error. This could even happen if
1792        the pattern terminated after [[ but there just happened to be a sequence of
1793        letters, a binary zero, and a closing ] in the memory that followed.
1795    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1796        over the years. Originally (before any Unicode support), just the bottom 8
1797        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1798        output from "man perlunicode" includes this:
1800          The regular expression compiler produces polymorphic opcodes.  That
1801          is, the pattern adapts to the data and automatically switches to
1802          the Unicode character scheme when presented with Unicode data--or
1803          instead uses a traditional byte scheme when presented with byte
1804          data.
1806        Sadly, a wide octal escape does not cause a switch, and in a string with
1807        no other multibyte characters, these octal escapes are treated as before.
1808        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1809        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1810        Unicode string.
1812        I have not perpetrated such confusion in PCRE. Up till now, it took just
1813        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1814        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1815        translate to the appropriate multibyte character.
1817    29. Applied some refactoring to reduce the number of warnings from Microsoft
1818        and Borland compilers. This has included removing the fudge introduced
1819        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1820        a warning about an unused variable.
1822    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1823        characters since release 4.0, because Perl (from release 5.004) does not.
1824        [Or at least, is documented not to: some releases seem to be in conflict
1825        with the documentation.] However, when a pattern was studied with
1826        pcre_study() and all its branches started with \s, PCRE still included VT
1827        as a possible starting character. Of course, this did no harm; it just
1828        caused an unnecessary match attempt.
1830    22. Removed a now-redundant internal flag bit that recorded the fact that case
1831        dependency changed within the pattern. This was once needed for "required
1832        byte" processing, but is no longer used. This recovers a now-scarce options
1833        bit. Also moved the least significant internal flag bit to the most-
1834        significant bit of the word, which was not previously used (hangover from
1835        the days when it was an int rather than a uint) to free up another bit for
1836        the future.
1838    23. Added support for CRLF line endings as well as CR and LF. As well as the
1839        default being selectable at build time, it can now be changed at runtime
1840        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1841        specify that it is scanning data with non-default line endings.
1843    24. Changed the definition of CXXLINK to make it agree with the definition of
1844        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1846    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1847        recursions. This makes a big different to stack usage for some patterns.
1849    26. If a subpattern containing a named recursion or subroutine reference such
1850        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1851        the space required for the compiled pattern went wrong and gave too small a
1852        value. Depending on the environment, this could lead to "Failed: internal
1853        error: code overflow at offset 49" or "glibc detected double free or
1854        corruption" errors.
1856    27. Applied patches from Google (a) to support the new newline modes and (b) to
1857        advance over multibyte UTF-8 characters in GlobalReplace.
1859    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1860        difference for some implementation of PCRE in some Windows version.
1862    29. Added some extra testing facilities to pcretest:
1864        \q<number>   in a data line sets the "match limit" value
1865        \Q<number>   in a data line sets the "match recursion limt" value
1866        -S <number>  sets the stack size, where <number> is in megabytes
1868        The -S option isn't available for Windows.
1871    Version 6.6 06-Feb-06
1872    ---------------------
1874     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1875        in pcreposix.h. I have copied the definition from pcre.h.
1877     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1878        because pcre.h is no longer a built file.
1880     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1881        not normally included in the compiled code.
1884    Version 6.5 01-Feb-06
1885    ---------------------
1887     1. When using the partial match feature with pcre_dfa_exec(), it was not
1888        anchoring the second and subsequent partial matches at the new starting
1889        point. This could lead to incorrect results. For example, with the pattern
1890        /1234/, partially matching against "123" and then "a4" gave a match.
1892     2. Changes to pcregrep:
1894        (a) All non-match returns from pcre_exec() were being treated as failures
1895            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1896            error message is output. Some extra information is given for the
1897            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1898            probably the only errors that are likely to be caused by users (by
1899            specifying a regex that has nested indefinite repeats, for instance).
1900            If there are more than 20 of these errors, pcregrep is abandoned.
1902        (b) A binary zero was treated as data while matching, but terminated the
1903            output line if it was written out. This has been fixed: binary zeroes
1904            are now no different to any other data bytes.
1906        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1907            used to set a locale for matching. The --locale=xxxx long option has
1908            been added (no short equivalent) to specify a locale explicitly on the
1909            pcregrep command, overriding the environment variables.
1911        (d) When -B was used with -n, some line numbers in the output were one less
1912            than they should have been.
1914        (e) Added the -o (--only-matching) option.
1916        (f) If -A or -C was used with -c (count only), some lines of context were
1917            accidentally printed for the final match.
1919        (g) Added the -H (--with-filename) option.
1921        (h) The combination of options -rh failed to suppress file names for files
1922            that were found from directory arguments.
1924        (i) Added the -D (--devices) and -d (--directories) options.
1926        (j) Added the -F (--fixed-strings) option.
1928        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1930        (l) Added the --colo(u)r option.
1932        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1933            is not present by default.
1935     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1936        items such as (?R) or (?1), when the recursion could match a number of
1937        alternatives. If it matched one of the alternatives, but subsequently,
1938        outside the recursion, there was a failure, the code tried to back up into
1939        the recursion. However, because of the way PCRE is implemented, this is not
1940        possible, and the result was an incorrect result from the match.
1942        In order to prevent this happening, the specification of recursion has
1943        been changed so that all such subpatterns are automatically treated as
1944        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1946     4. I had overlooked the fact that, in some locales, there are characters for
1947        which isalpha() is true but neither isupper() nor islower() are true. In
1948        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1949        and ordfeminine) are like this. This affected the treatment of \w and \W
1950        when they appeared in character classes, but not when they appeared outside
1951        a character class. The bit map for "word" characters is now created
1952        separately from the results of isalnum() instead of just taking it from the
1953        upper, lower, and digit maps. (Plus the underscore character, of course.)
1955     5. The above bug also affected the handling of POSIX character classes such as
1956        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1957        permanent tables. Instead, the bit maps for such a class were previously
1958        created as the appropriate unions of the upper, lower, and digit bitmaps.
1959        Now they are created by subtraction from the [[:word:]] class, which has
1960        its own bitmap.
1962     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1963        It is created by subtracting the vertical space characters (\x09, \x0a,
1964        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1965        subtraction was done in the overall bitmap for a character class, meaning
1966        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1967        be recognized. This bug has been fixed.
1969     7. Patches from the folks at Google:
1971          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1972          real life, but is still worth protecting against".
1974          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1975          regular expressions".
1977          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1978          have it.
1980          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1981          "configure" and the latter not, in order to fix a problem somebody had
1982          with compiling the Arg class on HP-UX.
1984          (e) Improve the error-handling of the C++ wrapper a little bit.
1986          (f) New tests for checking recursion limiting.
1988     8. The pcre_memmove() function, which is used only if the environment does not
1989        have a standard memmove() function (and is therefore rarely compiled),
1990        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1991        returning a result (though PCRE never actually uses the result).
1993     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1994        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1995        returned instead of calling malloc() with an overflowing number that would
1996        most likely cause subsequent chaos.
1998    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2000    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2001        with this option is matched, the nmatch and pmatch options of regexec() are
2002        ignored.
2004    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2005        provided in case anyone wants to the the POSIX interface with UTF-8
2006        strings.
2008    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2009        C++ linking (needed for some HP-UX environments).
2011    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2012        (unused parameter) and in the pcre_printint() function (omitted "default"
2013        switch label when the default is to do nothing).
2015    15. Added some code to make it possible, when PCRE is compiled as a C++
2016        library, to replace subject pointers for pcre_exec() with a smart pointer
2017        class, thus making it possible to process discontinuous strings.
2019    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2020        much the same function. They were added by different people who were trying
2021        to make PCRE easy to compile on non-Unix systems. It has been suggested
2022        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2023        for compiling on Windows systems. I have therefore replaced it with
2024        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2025        defaults to "extern" for C or "extern C" for C++, which works fine on
2026        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2027        SCOPE with something explicit in config.h. In addition:
2029        (a) pcreposix.h still had just "extern" instead of either of these macros;
2030            I have replaced it with PCRE_DATA_SCOPE.
2032        (b) Functions such as _pcre_xclass(), which are internal to the library,
2033            but external in the C sense, all had PCRE_EXPORT in their definitions.
2034            This is apparently wrong for the Windows case, so I have removed it.
2035            (It makes no difference on Unix-like systems.)
2037    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2038        of recursive calls to match(). This is different to MATCH_LIMIT because
2039        that limits the total number of calls to match(), not all of which increase
2040        the depth of recursion. Limiting the recursion depth limits the amount of
2041        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2042        when PCRE is compiled, and changed at run time. A patch from Google adds
2043        this functionality to the C++ interface.
2045    18. Changes to the handling of Unicode character properties:
2047        (a) Updated the table to Unicode 4.1.0.
2049        (b) Recognize characters that are not in the table as "Cn" (undefined).
2051        (c) I revised the way the table is implemented to a much improved format
2052            which includes recognition of ranges. It now supports the ranges that
2053            are defined in UnicodeData.txt, and it also amalgamates other
2054            characters into ranges. This has reduced the number of entries in the
2055            table from around 16,000 to around 3,000, thus reducing its size
2056            considerably. I realized I did not need to use a tree structure after
2057            all - a binary chop search is just as efficient. Having reduced the
2058            number of entries, I extended their size from 6 bytes to 8 bytes to
2059            allow for more data.
2061        (d) Added support for Unicode script names via properties such as \p{Han}.
2063    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2064        matching that character.
2066    20. When matching a repeated Unicode property with a minimum greater than zero,
2067        (for example \pL{2,}), PCRE could look past the end of the subject if it
2068        reached it while seeking the minimum number of characters. This could
2069        happen only if some of the characters were more than one byte long, because
2070        there is a check for at least the minimum number of bytes.
2072    21. Refactored the implementation of \p and \P so as to be more general, to
2073        allow for more different types of property in future. This has changed the
2074        compiled form incompatibly. Anybody with saved compiled patterns that use
2075        \p or \P will have to recompile them.
2077    22. Added "Any" and "L&" to the supported property types.
2079    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2080        but give a compile time error if the value is greater than 0xff.
2082    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2083        accidentally not being installed or uninstalled.
2085    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2086        made were to insert the current release number. This seemed silly, because
2087        it made things harder for people building PCRE on systems that don't run
2088        "configure". I have turned pcre.h into a distributed file, no longer built
2089        by "configure", with the version identification directly included. There is
2090        no longer a pcre.h.in file.
2092        However, this change necessitated a change to the pcre-config script as
2093        well. It is built from pcre-config.in, and one of the substitutions was the
2094        release number. I have updated configure.ac so that ./configure now finds
2095        the release number by grepping pcre.h.
2097    26. Added the ability to run the tests under valgrind.
2100  Version 6.4 05-Sep-05  Version 6.4 05-Sep-05
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