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

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