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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.12 12-Jan-2011
5    ------------------------
7    1.  Fixed some typos in the markup of the man pages, and wrote a script that
8        checks for such things as part of the documentation building process.
10    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
11        --match-limit and --recursion-limit options (added for 8.11). In
12        particular, this made one of the standard tests crash. (The integer value
13        went into the wrong half of a long int.)
15    3.  If the --colour option was given to pcregrep with -v (invert match), it
16        did strange things, either producing crazy output, or crashing. It should,
17        of course, ignore a request for colour when reporting lines that do not
18        match.
20    4.  If pcregrep was compiled under Windows, there was a reference to the
21        function pcregrep_exit() before it was defined. I am assuming this was
22        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
23        reported by a user. I've moved the definition above the reference.
26    Version 8.11 10-Dec-2010
27    ------------------------
29    1.  (*THEN) was not working properly if there were untried alternatives prior
30        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
31        backtracked to try for "b" instead of moving to the next alternative branch
32        at the same level (in this case, to look for "c"). The Perl documentation
33        is clear that when (*THEN) is backtracked onto, it goes to the "next
34        alternative in the innermost enclosing group".
36    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
37        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
38        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
39        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
40        (*THEN).
42    3.  If \s appeared in a character class, it removed the VT character from
43        the class, even if it had been included by some previous item, for example
44        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
45        of \s, but is part of the POSIX "space" class.)
47    4.  A partial match never returns an empty string (because you can always
48        match an empty string at the end of the subject); however the checking for
49        an empty string was starting at the "start of match" point. This has been
50        changed to the "earliest inspected character" point, because the returned
51        data for a partial match starts at this character. This means that, for
52        example, /(?<=abc)def/ gives a partial match for the subject "abc"
53        (previously it gave "no match").
55    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
56        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
57        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
58        has an implication that the given string is incomplete (because a partial
59        match is preferred over a full match). For this reason, these items now
60        give a partial match in this situation. [Aside: previously, the one case
61        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
62        match rather than a full match, which was wrong by the old rules, but is
63        now correct.]
65    6.  There was a bug in the handling of #-introduced comments, recognized when
66        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
67        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
68        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
69        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
70        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
71        places in pcre_compile().
73    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
74        comments when looking ahead for named forward references to subpatterns,
75        the only newline sequence it recognized was NL. It now handles newlines
76        according to the set newline convention.
78    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
79        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
80        cater for a lack of strerror(). These oversights have been fixed.
82    9.  Added --match-limit and --recursion-limit to pcregrep.
84    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
86    11. When the -o option was used, pcregrep was setting a return code of 1, even
87        when matches were found, and --line-buffered was not being honoured.
89    12. Added an optional parentheses number to the -o and --only-matching options
90        of pcregrep.
92    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
93        can match an empty string. The code to do it in pcretest and pcredemo
94        needed fixing:
96        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
97            only one byte after an empty string match just before CRLF (this case
98            just got forgotten; "any" and "anycrlf" were OK).
100        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
101            mode when an empty string match preceded an ASCII character followed by
102            a non-ASCII character. (The code for advancing by one character rather
103            than one byte was nonsense.)
105        (c) The pcredemo.c sample program did not have any code at all to handle
106            the cases when CRLF is a valid newline sequence.
108    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
109        as a starting offset was within the subject string. There is now a new
110        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
111        negative or greater than the length of the string. In order to test this,
112        pcretest is extended to allow the setting of negative starting offsets.
114    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
115        starting offset points to the beginning of a UTF-8 character was
116        unnecessarily clumsy. I tidied it up.
118    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
119        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
121    17. Nobody had reported that the --include_dir option, which was added in
122        release 7.7 should have been called --include-dir (hyphen, not underscore)
123        for compatibility with GNU grep. I have changed it to --include-dir, but
124        left --include_dir as an undocumented synonym, and the same for
125        --exclude-dir, though that is not available in GNU grep, at least as of
126        release 2.5.4.
128    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
129        characters from a string of bytes) have been redefined so as not to use
130        loops, in order to improve performance in some environments. At the same
131        time, I abstracted some of the common code into auxiliary macros to save
132        repetition (this should not affect the compiled code).
134    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
135        compile-time error is now given if \c is not followed by an ASCII
136        character, that is, a byte less than 128. (In EBCDIC mode, the code is
137        different, and any byte value is allowed.)
139    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
140        START_OPTIMIZE option, which is now allowed at compile time - but just
141        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
142        to pcregrep and other applications that have no direct access to PCRE
143        options. The new /Y option in pcretest sets this option when calling
144        pcre_compile().
146    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
147        back references. Groups containing recursive back references were forced to
148        be atomic by that change, but in the case of named groups, the amount of
149        memory required was incorrectly computed, leading to "Failed: internal
150        error: code overflow". This has been fixed.
152    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
153        pcretest.c, to avoid build problems in some Borland environments.
156    Version 8.10 25-Jun-2010
157    ------------------------
159    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
160        THEN.
162    2.  (*ACCEPT) was not working when inside an atomic group.
164    3.  Inside a character class, \B is treated as a literal by default, but
165        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
166        causes the error). The code is unchanged, but I tidied the documentation.
168    4.  Inside a character class, PCRE always treated \R and \X as literals,
169        whereas Perl faults them if its -w option is set. I have changed PCRE so
170        that it faults them when PCRE_EXTRA is set.
172    5.  Added support for \N, which always matches any character other than
173        newline. (It is the same as "." when PCRE_DOTALL is not set.)
175    6.  When compiling pcregrep with newer versions of gcc which may have
176        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
177        declared with attribute warn_unused_result" were given. Just casting the
178        result to (void) does not stop the warnings; a more elaborate fudge is
179        needed. I've used a macro to implement this.
181    7.  Minor change to pcretest.c to avoid a compiler warning.
183    8.  Added four artifical Unicode properties to help with an option to make
184        \s etc use properties (see next item). The new properties are: Xan
185        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
187    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
188        use Unicode properties. (*UCP) at the start of a pattern can be used to set
189        this option. Modified pcretest to add /W to test this facility. Added
190        REG_UCP to make it available via the POSIX interface.
192    10. Added --line-buffered to pcregrep.
194    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
195        studied, and the match started with a letter with a code point greater than
196        127 whose first byte was different to the first byte of the other case of
197        the letter, the other case of this starting letter was not recognized
198        (#976).
200    12. If a pattern that was studied started with a repeated Unicode property
201        test, for example, \p{Nd}+, there was the theoretical possibility of
202        setting up an incorrect bitmap of starting bytes, but fortunately it could
203        not have actually happened in practice until change 8 above was made (it
204        added property types that matched character-matching opcodes).
206    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
207        possible starting bytes for non-anchored patterns.
209    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
210        \R, and also a number of cases that involve Unicode properties, both
211        explicit and implicit when PCRE_UCP is set.
213    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
214        input, it could crash or give wrong results if characters with values
215        greater than 0xc0 were present in the subject string. (Detail: it assumed
216        UTF-8 input when processing these items.)
218    16. Added a lot of (int) casts to avoid compiler warnings in systems where
219        size_t is 64-bit (#991).
221    17. Added a check for running out of memory when PCRE is compiled with
222        --disable-stack-for-recursion (#990).
224    18. If the last data line in a file for pcretest does not have a newline on
225        the end, a newline was missing in the output.
227    19. The default pcre_chartables.c file recognizes only ASCII characters (values
228        less than 128) in its various bitmaps. However, there is a facility for
229        generating tables according to the current locale when PCRE is compiled. It
230        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
231        characters, are recognized by isspace() and therefore were getting set in
232        these tables, and indeed these tables seem to approximate to ISO 8859. This
233        caused a problem in UTF-8 mode when pcre_study() was used to create a list
234        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
235        which of course cannot start UTF-8 characters. I have changed the code so
236        that only real ASCII characters (less than 128) and the correct starting
237        bytes for UTF-8 encodings are set for characters greater than 127 when in
238        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
239        altogether.)
241    20. Added the /T option to pcretest so as to be able to run tests with non-
242        standard character tables, thus making it possible to include the tests
243        used for 19 above in the standard set of tests.
245    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
246        reference to a subpattern the other side of a comment that contains an
247        opening parenthesis caused either an internal compiling error, or a
248        reference to the wrong subpattern.
251    Version 8.02 19-Mar-2010
252    ------------------------
254    1.  The Unicode data tables have been updated to Unicode 5.2.0.
256    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
257        configured.
259    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
260        original author of that file, following a query about its status.
262    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
263        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
265    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
266        quantifier applied to a forward-referencing subroutine call, could compile
267        incorrect code or give the error "internal error: previously-checked
268        referenced subpattern not found".
270    6.  Both MS Visual Studio and Symbian OS have problems with initializing
271        variables to point to external functions. For these systems, therefore,
272        pcre_malloc etc. are now initialized to local functions that call the
273        relevant global functions.
275    7.  There were two entries missing in the vectors called coptable and poptable
276        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
277        I've fixed the data, and added a kludgy way of testing at compile time that
278        the lengths are correct (equal to the number of opcodes).
280    8.  Following on from 7, I added a similar kludge to check the length of the
281        eint vector in pcreposix.c.
283    9.  Error texts for pcre_compile() are held as one long string to avoid too
284        much relocation at load time. To find a text, the string is searched,
285        counting zeros. There was no check for running off the end of the string,
286        which could happen if a new error number was added without updating the
287        string.
289    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
291    11. \K was not working if it appeared in an atomic group or in a group that
292        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
293        \K is "not well defined" if used in an assertion. PCRE now accepts it if
294        the assertion is positive, but not if it is negative.
296    12. Change 11 fortuitously reduced the size of the stack frame used in the
297        "match()" function of pcre_exec.c by one pointer. Forthcoming
298        implementation of support for (*MARK) will need an extra pointer on the
299        stack; I have reserved it now, so that the stack frame size does not
300        decrease.
302    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
303        item in branch that calls a recursion is a subroutine call - as in the
304        second branch in the above example - was incorrectly given the compile-
305        time error "recursive call could loop indefinitely" because pcre_compile()
306        was not correctly checking the subroutine for matching a non-empty string.
308    14. The checks for overrunning compiling workspace could trigger after an
309        overrun had occurred. This is a "should never occur" error, but it can be
310        triggered by pathological patterns such as hundreds of nested parentheses.
311        The checks now trigger 100 bytes before the end of the workspace.
313    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
316    Version 8.01 19-Jan-2010
317    ------------------------
319    1.  If a pattern contained a conditional subpattern with only one branch (in
320        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
321        computed the wrong minimum data length (which is of course zero for such
322        subpatterns). This could cause incorrect "no match" results.
324    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
325        the pattern is reset in the first branch, pcre_compile() failed with
326        "internal error: code overflow at offset...". This happened only when
327        the reset was to the original external option setting. (An optimization
328        abstracts leading options settings into an external setting, which was the
329        cause of this.)
331    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
332        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
333        assertion pattern did not match (meaning that the assertion was true), it
334        was incorrectly treated as false if the SKIP had been reached during the
335        matching. This also applied to assertions used as conditions.
337    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
338        assertion subpattern, including such a pattern used as a condition,
339        unpredictable results occurred, instead of the error return
342    5.  The C++ GlobalReplace function was not working like Perl for the special
343        situation when an empty string is matched. It now does the fancy magic
344        stuff that is necessary.
346    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
347        removed. (These were left over from very, very early versions of PCRE.)
349    7.  Some cosmetic changes to the code to make life easier when compiling it
350        as part of something else:
352        (a) Change DEBUG to PCRE_DEBUG.
354        (b) In pcre_compile(), rename the member of the "branch_chain" structure
355            called "current" as "current_branch", to prevent a collision with the
356            Linux macro when compiled as a kernel module.
358        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
359            prevent a collision with the Linux macro when compiled as a kernel
360            module.
362    8.  In pcre_compile() there are some checks for integer overflows that used to
363        cast potentially large values to (double). This has been changed to that
364        when building, a check for int64_t is made, and if it is found, it is used
365        instead, thus avoiding the use of floating point arithmetic. (There is no
366        other use of FP in PCRE.) If int64_t is not found, the fallback is to
367        double.
369    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
370        2005 (difference between two addresses compared to an unsigned value).
372    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
373        custom one, because of the following reported problem in Windows:
375          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
376              under Win32.
377          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
378              therefore missing the function definition.
379          - The compiler thus generates a "C" signature for the test function.
380          - The linker fails to find the "C" function.
381          - PCRE fails to configure if asked to do so against libbz2.
383    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
384        messages were output:
386          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
387          rerunning libtoolize, to keep the correct libtool macros in-tree.
388          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
390        I have done both of these things.
392    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
393        most of the time, it *can* run out if it is given a pattern that contains a
394        runaway infinite recursion. I updated the discussion in the pcrestack man
395        page.
397    13. Now that we have gone to the x.xx style of version numbers, the minor
398        version may start with zero. Using 08 or 09 is a bad idea because users
399        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
400        interpreted as invalid octal numbers. I've updated the previous comment in
401        configure.ac, and also added a check that gives an error if 08 or 09 are
402        used.
404    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
405        causing partial matching to fail when the end of the subject matched \W
406        in a UTF-8 pattern where \W was quantified with a minimum of 3.
408    15. There were some discrepancies between the declarations in pcre_internal.h
409        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
410        their definitions. The declarations used "const uschar *" and the
411        definitions used USPTR. Even though USPTR is normally defined as "const
412        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
413        reported that: "This difference in casting confuses some C++ compilers, for
414        example, SunCC recognizes above declarations as different functions and
415        generates broken code for hbpcre." I have changed the declarations to use
416        USPTR.
418    16. GNU libtool is named differently on some systems. The autogen.sh script now
419        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
420        (FreeBSD).
422    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
423        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
424        comment: "Figure out how to create a longlong from a string: strtoll and
425        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
426        instance, but it only takes 2 args instead of 3!"
428    18. A subtle bug concerned with back references has been fixed by a change of
429        specification, with a corresponding code fix. A pattern such as
430        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
431        refers, was giving matches when it shouldn't. For example, xa=xaaa would
432        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
433        same bug. Such groups have to be quantified to be useful, or contained
434        inside another quantified group. (If there's no repetition, the reference
435        can never match.) The problem arises because, having left the group and
436        moved on to the rest of the pattern, a later failure that backtracks into
437        the group uses the captured value from the final iteration of the group
438        rather than the correct earlier one. I have fixed this in PCRE by forcing
439        any group that contains a reference to itself to be an atomic group; that
440        is, there cannot be any backtracking into it once it has completed. This is
441        similar to recursive and subroutine calls.
444    Version 8.00 19-Oct-09
445    ----------------------
447    1.  The table for translating pcre_compile() error codes into POSIX error codes
448        was out-of-date, and there was no check on the pcre_compile() error code
449        being within the table. This could lead to an OK return being given in
450        error.
452    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
453        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
454        in a Windows environment.
456    3.  The pcregrep --count option prints the count for each file even when it is
457        zero, as does GNU grep. However, pcregrep was also printing all files when
458        --files-with-matches was added. Now, when both options are given, it prints
459        counts only for those files that have at least one match. (GNU grep just
460        prints the file name in this circumstance, but including the count seems
461        more useful - otherwise, why use --count?) Also ensured that the
462        combination -clh just lists non-zero counts, with no names.
464    4.  The long form of the pcregrep -F option was incorrectly implemented as
465        --fixed_strings instead of --fixed-strings. This is an incompatible change,
466        but it seems right to fix it, and I didn't think it was worth preserving
467        the old behaviour.
469    5.  The command line items --regex=pattern and --regexp=pattern were not
470        recognized by pcregrep, which required --regex pattern or --regexp pattern
471        (with a space rather than an '='). The man page documented the '=' forms,
472        which are compatible with GNU grep; these now work.
474    6.  No libpcreposix.pc file was created for pkg-config; there was just
475        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
477    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
478        when UCP support is not needed, by modifying the Python script that
479        generates it from Unicode data files. This should not matter if the module
480        is correctly used as a library, but I received one complaint about 50K of
481        unwanted data. My guess is that the person linked everything into his
482        program rather than using a library. Anyway, it does no harm.
484    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
485        was a minimum greater than 1 for a wide character in a possessive
486        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
487        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
488        character. Chaos in the form of incorrect output or a compiling loop could
489        result.
491    9.  The restrictions on what a pattern can contain when partial matching is
492        requested for pcre_exec() have been removed. All patterns can now be
493        partially matched by this function. In addition, if there are at least two
494        slots in the offset vector, the offset of the earliest inspected character
495        for the match and the offset of the end of the subject are set in them when
496        PCRE_ERROR_PARTIAL is returned.
498    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
499        synonymous with PCRE_PARTIAL, for backwards compatibility, and
500        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
501        and may be more useful for multi-segment matching.
503    11. Partial matching with pcre_exec() is now more intuitive. A partial match
504        used to be given if ever the end of the subject was reached; now it is
505        given only if matching could not proceed because another character was
506        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
507        string "Z", which now yields "no match" instead of "partial match". In the
508        case of pcre_dfa_exec(), "no match" is given if every matching path for the
509        final character ended with (*FAIL).
511    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
512        if the pattern had a "must contain" character that was already found in the
513        earlier partial match, unless partial matching was again requested. For
514        example, with the pattern /dog.(body)?/, the "must contain" character is
515        "g". If the first part-match was for the string "dog", restarting with
516        "sbody" failed. This bug has been fixed.
518    13. The string returned by pcre_dfa_exec() after a partial match has been
519        changed so that it starts at the first inspected character rather than the
520        first character of the match. This makes a difference only if the pattern
521        starts with a lookbehind assertion or \b or \B (\K is not supported by
522        pcre_dfa_exec()). It's an incompatible change, but it makes the two
523        matching functions compatible, and I think it's the right thing to do.
525    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
526        so that the demonstration program is easily available in environments where
527        PCRE has not been installed from source.
529    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
530        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
531        library.
533    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
534        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
535        is not the first non-POSIX option to be added. Clearly some people find
536        these options useful.
538    17. If a caller to the POSIX matching function regexec() passes a non-zero
539        value for nmatch with a NULL value for pmatch, the value of
540        nmatch is forced to zero.
542    18. RunGrepTest did not have a test for the availability of the -u option of
543        the diff command, as RunTest does. It now checks in the same way as
544        RunTest, and also checks for the -b option.
546    19. If an odd number of negated classes containing just a single character
547        interposed, within parentheses, between a forward reference to a named
548        subpattern and the definition of the subpattern, compilation crashed with
549        an internal error, complaining that it could not find the referenced
550        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
551        [The bug was that it was starting one character too far in when skipping
552        over the character class, thus treating the ] as data rather than
553        terminating the class. This meant it could skip too much.]
555    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
556        /g option in pcretest when the pattern contains \K, which makes it possible
557        to have an empty string match not at the start, even when the pattern is
558        anchored. Updated pcretest and pcredemo to use this option.
560    21. If the maximum number of capturing subpatterns in a recursion was greater
561        than the maximum at the outer level, the higher number was returned, but
562        with unset values at the outer level. The correct (outer level) value is
563        now given.
565    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
566        PCRE did not set those parentheses (unlike Perl). I have now found a way to
567        make it do so. The string so far is captured, making this feature
568        compatible with Perl.
570    23. The tests have been re-organized, adding tests 11 and 12, to make it
571        possible to check the Perl 5.10 features against Perl 5.10.
573    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
574        pattern matches a fixed length string. PCRE did not allow this; now it
575        does. Neither allows recursion.
577    25. I finally figured out how to implement a request to provide the minimum
578        length of subject string that was needed in order to match a given pattern.
579        (It was back references and recursion that I had previously got hung up
580        on.) This code has now been added to pcre_study(); it finds a lower bound
581        to the length of subject needed. It is not necessarily the greatest lower
582        bound, but using it to avoid searching strings that are too short does give
583        some useful speed-ups. The value is available to calling programs via
584        pcre_fullinfo().
586    26. While implementing 25, I discovered to my embarrassment that pcretest had
587        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
588        study optimizations had never been tested with that matching function.
589        Oops. What is worse, even when it was passed study data, there was a bug in
590        pcre_dfa_exec() that meant it never actually used it. Double oops. There
591        were also very few tests of studied patterns with pcre_dfa_exec().
593    27. If (?| is used to create subpatterns with duplicate numbers, they are now
594        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
595        on the other side of the coin, they are no longer allowed to have different
596        names, because these cannot be distinguished in PCRE, and this has caused
597        confusion. (This is a difference from Perl.)
599    28. When duplicate subpattern names are present (necessarily with different
600        numbers, as required by 27 above), and a test is made by name in a
601        conditional pattern, either for a subpattern having been matched, or for
602        recursion in such a pattern, all the associated numbered subpatterns are
603        tested, and the overall condition is true if the condition is true for any
604        one of them. This is the way Perl works, and is also more like the way
605        testing by number works.
608    Version 7.9 11-Apr-09
609    ---------------------
611    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
612        (pcretest), all targets were linked against these libraries. This included
613        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
614        libraries. This caused unwanted dependencies to be created. This problem
615        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
616        pcretest is linked with readline.
618    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
619        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
620        moved outside it again, because FALSE and TRUE are already defined in AIX,
621        but BOOL is not.
623    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
624        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
626    4.  The pcregrep documentation said spaces were inserted as well as colons (or
627        hyphens) following file names and line numbers when outputting matching
628        lines. This is not true; no spaces are inserted. I have also clarified the
629        wording for the --colour (or --color) option.
631    5.  In pcregrep, when --colour was used with -o, the list of matching strings
632        was not coloured; this is different to GNU grep, so I have changed it to be
633        the same.
635    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
636        each matching line was coloured. Now it goes on to look for further matches
637        of any of the test patterns, which is the same behaviour as GNU grep.
639    7.  A pattern that could match an empty string could cause pcregrep to loop; it
640        doesn't make sense to accept an empty string match in pcregrep, so I have
641        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
642        seems to be how GNU grep behaves.
644    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
645        start or after a newline", because the conditional assertion was not being
646        correctly handled. The rule now is that both the assertion and what follows
647        in the first alternative must satisfy the test.
649    9.  If auto-callout was enabled in a pattern with a conditional group whose
650        condition was an assertion, PCRE could crash during matching, both with
651        pcre_exec() and pcre_dfa_exec().
653    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
654        used for matching.
656    11. Unicode property support in character classes was not working for
657        characters (bytes) greater than 127 when not in UTF-8 mode.
659    12. Added the -M command line option to pcretest.
661    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
663    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
665    16. Added comments and documentation about mis-use of no_arg in the C++
666        wrapper.
668    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
669        from Martin Jerabek that uses macro names for all relevant character and
670        string constants.
672    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
673        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
674        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
675        these, but not everybody uses configure.
677    19. A conditional group that had only one branch was not being correctly
678        recognized as an item that could match an empty string. This meant that an
679        enclosing group might also not be so recognized, causing infinite looping
680        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
681        with the subject "ab", where knowledge that the repeated group can match
682        nothing is needed in order to break the loop.
684    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
685        exec(), but without supplying a callout function, matching went wrong.
687    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
688        leak if the size of the offset vector was greater than 30. When the vector
689        is smaller, the saved offsets during recursion go onto a local stack
690        vector, but for larger vectors malloc() is used. It was failing to free
691        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
692        error, in fact).
694    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
695        heapframe that is used only when UTF-8 support is enabled. This caused no
696        problem, but was untidy.
698    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
699        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
700        included within another project.
702    24. Steven Van Ingelgem's patches to add more options to the CMake support,
703        slightly modified by me:
705          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
706              not building pcregrep.
708          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
709              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
711    25. Forward references, both numeric and by name, in patterns that made use of
712        duplicate group numbers, could behave incorrectly or give incorrect errors,
713        because when scanning forward to find the reference group, PCRE was not
714        taking into account the duplicate group numbers. A pattern such as
715        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
717    26. Changed a few more instances of "const unsigned char *" to USPTR, making
718        the feature of a custom pointer more persuasive (as requested by a user).
720    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
721        pcretest.c, inside #ifndefs, because it seems they are sometimes already
722        pre-defined.
724    28. Added support for (*UTF8) at the start of a pattern.
726    29. Arrange for flags added by the "release type" setting in CMake to be shown
727        in the configuration summary.
730    Version 7.8 05-Sep-08
731    ---------------------
733    1.  Replaced UCP searching code with optimized version as implemented for Ad
734        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
735        stage table and inline lookup instead of a function, giving speed ups of 2
736        to 5 times on some simple patterns that I tested. Permission was given to
737        distribute the MultiStage2.py script that generates the tables (it's not in
738        the tarball, but is in the Subversion repository).
740    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
741        scripts.
743    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
744        a group with a zero qualifier. The result of the study could be incorrect,
745        or the function might crash, depending on the pattern.
747    4.  Caseless matching was not working for non-ASCII characters in back
748        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
749        It now works when Unicode Property Support is available.
751    5.  In pcretest, an escape such as \x{de} in the data was always generating
752        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
753        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
754        truncation.
756    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
758    7.  Added two (int) casts to pcregrep when printing the difference of two
759        pointers, in case they are 64-bit values.
761    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
762        test 2 if it fails.
764    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
765        and a #define of that name to empty if it is not externally set. This is to
766        allow users of MSVC to set it if necessary.
768    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
769        the convenience functions in the pcre_get.c source file.
771    11. An option change at the start of a pattern that had top-level alternatives
772        could cause overwriting and/or a crash. This command provoked a crash in
773        some environments:
775          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
777        This potential security problem was recorded as CVE-2008-2371.
779    12. For a pattern where the match had to start at the beginning or immediately
780        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
781        pcre_dfa_exec() could read past the end of the passed subject if there was
782        no match. To help with detecting such bugs (e.g. with valgrind), I modified
783        pcretest so that it places the subject at the end of its malloc-ed buffer.
785    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
786        exec() might read past the end of the data buffer in UTF-8 mode.
788    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
789        the data contained the byte 0x85 as part of a UTF-8 character within its
790        first line. This applied both to normal and DFA matching.
792    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
793        /^[^d]*?$/8 failed to match "abc".
795    16. Added a missing copyright notice to pcrecpp_internal.h.
797    17. Make it more clear in the documentation that values returned from
798        pcre_exec() in ovector are byte offsets, not character counts.
800    18. Tidied a few places to stop certain compilers from issuing warnings.
802    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
803        supplied by Stefan Weber. I made a further small update for 7.8 because
804        there is a change of source arrangements: the pcre_searchfuncs.c module is
805        replaced by pcre_ucd.c.
808    Version 7.7 07-May-08
809    ---------------------
811    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
812        a string to a long long, pretend we don't even have a long long." This is
813        done by checking for the strtoq, strtoll, and _strtoi64 functions.
815    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
816        pre-7.6 versions, which defined a global no_arg variable instead of putting
817        it in the RE class. (See also #8 below.)
819    3.  Remove a line of dead code, identified by coverity and reported by Nuno
820        Lopes.
822    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
824        (1) The include/exclude patterns were being applied to the whole pathnames
825            of files, instead of just to the final components.
827        (2) If there was more than one level of directory, the subdirectories were
828            skipped unless they satisfied the include/exclude conditions. This is
829            inconsistent with GNU grep (and could even be seen as contrary to the
830            pcregrep specification - which I improved to make it absolutely clear).
831            The action now is always to scan all levels of directory, and just
832            apply the include/exclude patterns to regular files.
834    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
835        --exclude_dir in the tests to avoid scanning .svn directories.
837    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
838        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
839        doesn't support NULs in patterns.
841    7.  Added some missing "const"s to declarations of static tables in
842        pcre_compile.c and pcre_dfa_exec.c.
844    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
845        caused by fix #2  above. (Subsequently also a second patch to fix the
846        first patch. And a third patch - this was a messy problem.)
848    9.  Applied Craig's patch to remove the use of push_back().
850    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
851        matching function regexec().
853    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
854        which, however, unlike Perl's \g{...}, are subroutine calls, not back
855        references. PCRE supports relative numbers with this syntax (I don't think
856        Oniguruma does).
858    12. Previously, a group with a zero repeat such as (...){0} was completely
859        omitted from the compiled regex. However, this means that if the group
860        was called as a subroutine from elsewhere in the pattern, things went wrong
861        (an internal error was given). Such groups are now left in the compiled
862        pattern, with a new opcode that causes them to be skipped at execution
863        time.
865    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
866        to the way PCRE behaves:
868        (a) A lone ] character is dis-allowed (Perl treats it as data).
870        (b) A back reference to an unmatched subpattern matches an empty string
871            (Perl fails the current match path).
873        (c) A data ] in a character class must be notated as \] because if the
874            first data character in a class is ], it defines an empty class. (In
875            Perl it is not possible to have an empty class.) The empty class []
876            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
877            The negative empty class [^] matches any one character, independently
878            of the DOTALL setting.
880    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
881        non-existent subpattern following a character class starting with ']' and
882        containing () gave an internal compiling error instead of "reference to
883        non-existent subpattern". Fortunately, when the pattern did exist, the
884        compiled code was correct. (When scanning forwards to check for the
885        existencd of the subpattern, it was treating the data ']' as terminating
886        the class, so got the count wrong. When actually compiling, the reference
887        was subsequently set up correctly.)
889    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
890        it was being rejected as not supported by pcre_dfa_exec(), even though
891        other assertions are supported. I have made pcre_dfa_exec() support
892        (*FAIL).
894    16. The implementation of 13c above involved the invention of a new opcode,
895        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
896        cannot be changed at match time, I realized I could make a small
897        improvement to matching performance by compiling OP_ALLANY instead of
898        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
899        on the OP_ANY path.
901    17. Compiling pcretest on Windows with readline support failed without the
902        following two fixes: (1) Make the unistd.h include conditional on
903        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
905    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
906        ncurses library to be included for pcretest when ReadLine support is
907        requested, but also to allow for it to be overridden. This patch came from
908        Daniel Bergström.
910    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
911        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
912        any errors with the current Unicode tables. Thanks to Peter Kankowski for
913        spotting this.
916    Version 7.6 28-Jan-08
917    ---------------------
919    1.  A character class containing a very large number of characters with
920        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
921        overflow.
923    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
924        HAVE_LONG_LONG is not defined.
926    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
927        bring them up to date and include new features. This patch includes:
929        - Fixed PH's badly added libz and libbz2 support.
930        - Fixed a problem with static linking.
931        - Added pcredemo. [But later removed - see 7 below.]
932        - Fixed dftables problem and added an option.
933        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
934            HAVE_LONG_LONG.
935        - Added readline support for pcretest.
936        - Added an listing of the option settings after cmake has run.
938    4.  A user submitted a patch to Makefile that makes it easy to create
939        "pcre.dll" under mingw when using Configure/Make. I added stuff to
940        Makefile.am that cause it to include this special target, without
941        affecting anything else. Note that the same mingw target plus all
942        the other distribution libraries and programs are now supported
943        when configuring with CMake (see 6 below) instead of with
944        Configure/Make.
946    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
947        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
948        exported in the Windows port". It has not yet been confirmed that the patch
949        solves the problem, but it does no harm.
951    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
952        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
953        with CMake, and also correct the comment about stack recursion.
955    7.  Remove the automatic building of pcredemo from the ./configure system and
956        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
957        of a program that users should build themselves after PCRE is installed, so
958        building it automatically is not really right. What is more, it gave
959        trouble in some build environments.
961    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
964    Version 7.5 10-Jan-08
965    ---------------------
967    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
968        values in parens when parsing an RE using the C++ wrapper."
970    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
971        Characters greater than 255 were excluded from the class instead of being
972        included.
974    3.  The same bug as (2) above applied to negated POSIX classes such as
975        [:^space:].
977    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
978        defined or documented. It seems to have been a typo for PCRE_STATIC, so
979        I have changed it.
981    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
982        first named subpattern) and a construct such as (?&a) would reference the
983        first named subpattern whose name started with "a" (in other words, the
984        length check was missing). Both these problems are fixed. "Subpattern name
985        expected" is now given for (?&) (a zero-length name), and this patch also
986        makes it give the same error for \k'' (previously it complained that that
987        was a reference to a non-existent subpattern).
989    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
990        this is right because (?- can be followed by option settings as well as by
991        digits. I have, however, made the messages clearer.
993    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
994        than the number used in the conditional) now cause a compile-time error.
995        This is actually not compatible with Perl, which accepts such patterns, but
996        treats the conditional as always being FALSE (as PCRE used to), but it
997        seems to me that giving a diagnostic is better.
999    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1000        and messages.
1002    9.  Fix two occurrences of "backslash" in comments that should have been
1003        "backspace".
1005    10. Remove two redundant lines of code that can never be obeyed (their function
1006        was moved elsewhere).
1008    11. The program that makes PCRE's Unicode character property table had a bug
1009        which caused it to generate incorrect table entries for sequences of
1010        characters that have the same character type, but are in different scripts.
1011        It amalgamated them into a single range, with the script of the first of
1012        them. In other words, some characters were in the wrong script. There were
1013        thirteen such cases, affecting characters in the following ranges:
1015          U+002b0 - U+002c1
1016          U+0060c - U+0060d
1017          U+0061e - U+00612
1018          U+0064b - U+0065e
1019          U+0074d - U+0076d
1020          U+01800 - U+01805
1021          U+01d00 - U+01d77
1022          U+01d9b - U+01dbf
1023          U+0200b - U+0200f
1024          U+030fc - U+030fe
1025          U+03260 - U+0327f
1026          U+0fb46 - U+0fbb1
1027          U+10450 - U+1049d
1029    12. The -o option (show only the matching part of a line) for pcregrep was not
1030        compatible with GNU grep in that, if there was more than one match in a
1031        line, it showed only the first of them. It now behaves in the same way as
1032        GNU grep.
1034    13. If the -o and -v options were combined for pcregrep, it printed a blank
1035        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1036        does the same. The return code can be used to tell if there were any
1037        non-matching lines.
1039    14. Added --file-offsets and --line-offsets to pcregrep.
1041    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1042        infinitely looping recursion. The bug was that positive lookaheads were not
1043        being skipped when checking for a possible empty match (negative lookaheads
1044        and both kinds of lookbehind were skipped).
1046    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1047        inclusion of <windows.h> to before rather than after the definition of
1048        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1050    17. Specifying a possessive quantifier with a specific limit for a Unicode
1051        character property caused pcre_compile() to compile bad code, which led at
1052        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1053        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1054        caused the error; without that there was no problem.
1056    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1058    19. Added --enable-pcretest-libreadline.
1060    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1061        RE::GlobalReplace(). As a result, the number of replacements returned was
1062        double what it should be. I removed one of the increments, but Craig sent a
1063        later patch that removed the other one (the right fix) and added unit tests
1064        that check the return values (which was not done before).
1066    21. Several CMake things:
1068        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1069            the names libpcre and libpcreposix, not just pcre and pcreposix.
1071        (2) The above change means that pcretest and pcregrep are now correctly
1072            linked with the newly-built libraries, not previously installed ones.
1076    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1077        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1078        UTF-8 newline character). The key issue is that the pattern starts .*;
1079        this means that the match must be either at the beginning, or after a
1080        newline. The bug was in the code for advancing after a failed match and
1081        checking that the new position followed a newline. It was not taking
1082        account of UTF-8 characters correctly.
1084    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1085        character classes. PCRE was not treating the sequence [:...:] as a
1086        character class unless the ... were all letters. Perl, however, seems to
1087        allow any characters between [: and :], though of course it rejects as
1088        unknown any "names" that contain non-letters, because all the known class
1089        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1090        for example, whereas PCRE did not - it did not recognize a POSIX character
1091        class. This seemed a bit dangerous, so the code has been changed to be
1092        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1093        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1094        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1095        Perl does, and where it didn't before.
1097    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1098        Windows environments %n is disabled by default.
1101    Version 7.4 21-Sep-07
1102    ---------------------
1104    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1105        means that a class such as [\s] counted as "explicit reference to CR or
1106        LF". That isn't really right - the whole point of the change was to try to
1107        help when there was an actual mention of one of the two characters. So now
1108        the change happens only if \r or \n (or a literal CR or LF) character is
1109        encountered.
1111    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1112        of both had grown to the point where there were only 3 bits left.
1113        Fortunately, there was spare space in the data structure, and so I have
1114        moved the internal flags into a new 16-bit field to free up more option
1115        bits.
1117    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1118        but did not set the internal JCHANGED flag - either of these is enough to
1119        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1120        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1121        start sets both bits.
1123    4.  Added options (at build time, compile time, exec time) to change \R from
1124        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1126    5.  doc/pcresyntax.html was missing from the distribution.
1128    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1129        compatibility, even though it is no longer used.
1131    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1132        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1133        windows.h file is present (where different names are used). [This was
1134        reversed later after testing - see 16 below.]
1136    8.  Changed all #include <config.h> to #include "config.h". There were also
1137        some further <pcre.h> cases that I changed to "pcre.h".
1139    9.  When pcregrep was used with the --colour option, it missed the line ending
1140        sequence off the lines that it output.
1142    10. It was pointed out to me that arrays of string pointers cause lots of
1143        relocations when a shared library is dynamically loaded. A technique of
1144        using a single long string with a table of offsets can drastically reduce
1145        these. I have refactored PCRE in four places to do this. The result is
1146        dramatic:
1148          Originally:                          290
1149          After changing UCP table:            187
1150          After changing error message table:   43
1151          After changing table of "verbs"       36
1152          After changing table of Posix names   22
1154        Thanks to the folks working on Gregex for glib for this insight.
1156    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1157        unicode-properties was also set.
1159    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1161    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1162        checked only for CRLF.
1164    14. Added casts to pcretest.c to avoid compiler warnings.
1166    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1168    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1169        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1170        entirely. This removes changes made in 7 above.
1172    17. The CMake files have been updated, and there is now more information about
1173        building with CMake in the NON-UNIX-USE document.
1176    Version 7.3 28-Aug-07
1177    ---------------------
1179     1. In the rejigging of the build system that eventually resulted in 7.1, the
1180        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
1181        brackets there is not right, since it causes compilers to look for an
1182        installed pcre.h, not the version that is in the source that is being
1183        compiled (which of course may be different). I have changed it back to:
1185          #include "pcre.h"
1187        I have a vague recollection that the change was concerned with compiling in
1188        different directories, but in the new build system, that is taken care of
1189        by the VPATH setting the Makefile.
1191     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
1192        when the subject happened to end in the byte 0x85 (e.g. if the last
1193        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
1194        characters but of course it shouldn't be taken as a newline when it is part
1195        of another character. The bug was that, for an unlimited repeat of . in
1196        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
1197        characters when looking for a newline.
1199     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
1201     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1202        in debug output.
1204     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1205        long printing in the pcrecpp unittest when running under MinGW.
1207     6. ESC_K was left out of the EBCDIC table.
1209     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
1210        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
1211        limit also applies to "virtual nesting" when a pattern is recursive, and in
1212        this case 1000 isn't so big. I have been able to remove this limit at the
1213        expense of backing off one optimization in certain circumstances. Normally,
1214        when pcre_exec() would call its internal match() function recursively and
1215        immediately return the result unconditionally, it uses a "tail recursion"
1216        feature to save stack. However, when a subpattern that can match an empty
1217        string has an unlimited repetition quantifier, it no longer makes this
1218        optimization. That gives it a stack frame in which to save the data for
1219        checking that an empty string has been matched. Previously this was taken
1220        from the 1000-entry workspace that had been reserved. So now there is no
1221        explicit limit, but more stack is used.
1223     8. Applied Daniel's patches to solve problems with the import/export magic
1224        syntax that is required for Windows, and which was going wrong for the
1225        pcreposix and pcrecpp parts of the library. These were overlooked when this
1226        problem was solved for the main library.
1228     9. There were some crude static tests to avoid integer overflow when computing
1229        the size of patterns that contain repeated groups with explicit upper
1230        limits. As the maximum quantifier is 65535, the maximum group length was
1231        set at 30,000 so that the product of these two numbers did not overflow a
1232        32-bit integer. However, it turns out that people want to use groups that
1233        are longer than 30,000 bytes (though not repeat them that many times).
1234        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1235        made it possible to implement the integer overflow checks in a much more
1236        dynamic way, which I have now done. The artificial limitation on group
1237        length has been removed - we now have only the limit on the total length of
1238        the compiled pattern, which depends on the LINK_SIZE setting.
1240    10. Fixed a bug in the documentation for get/copy named substring when
1241        duplicate names are permitted. If none of the named substrings are set, the
1242        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1243        empty string.
1245    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1246        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1247        because the ] is interpreted as the first data character and the
1248        terminating ] is not found. PCRE has been made compatible with Perl in this
1249        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1250        cause memory overwriting.
1252    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1253        string has been matched (to stop an infinite loop). It was not recognizing
1254        a conditional subpattern that could match an empty string if that
1255        subpattern was within another subpattern. For example, it looped when
1256        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1257        condition was not nested. This bug has been fixed.
1259    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1260        past the start of the subject in the presence of bytes with the top bit
1261        set, for example "\x8aBCD".
1263    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1264        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1266    14. Optimized (?!) to (*FAIL).
1268    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1269        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1270        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1271        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1272        does: it's just the validity check that is more restrictive.
1274    16. Inserted checks for integer overflows during escape sequence (backslash)
1275        processing, and also fixed erroneous offset values for syntax errors during
1276        backslash processing.
1278    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1279        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1281    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1282        caused an overrun.
1284    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1285        something other than just ASCII characters) inside a group that had an
1286        unlimited repeat caused a loop at compile time (while checking to see
1287        whether the group could match an empty string).
1289    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1290        [\P{Any}] did so. (Error in the code for printing property names.)
1292    21. An orphan \E inside a character class could cause a crash.
1294    22. A repeated capturing bracket such as (A)? could cause a wild memory
1295        reference during compilation.
1297    23. There are several functions in pcre_compile() that scan along a compiled
1298        expression for various reasons (e.g. to see if it's fixed length for look
1299        behind). There were bugs in these functions when a repeated \p or \P was
1300        present in the pattern. These operators have additional parameters compared
1301        with \d, etc, and these were not being taken into account when moving along
1302        the compiled data. Specifically:
1304        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1305            length.
1307        (b) An item such as \pL+ within a repeated group could cause crashes or
1308            loops.
1310        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1311            "reference to non-existent subpattern" error.
1313        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1315    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1316        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1318    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1320    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1321        character were causing crashes (broken optimization).
1323    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1324        \p or \P) caused a compile-time loop.
1326    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1327        break. For example, the unstudied pattern [\r\n]A does not match the string
1328        "\r\nA" because change 7.0/46 below moves the current point on by two
1329        characters after failing to match at the start. However, the pattern \nA
1330        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1331        the same is true. There doesn't seem any very clean way out of this, but
1332        what I have chosen to do makes the common cases work: PCRE now takes note
1333        of whether there can be an explicit match for \r or \n anywhere in the
1334        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1335        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1336        pattern has explicit CR or LF references.
1338    29. Added (*CR) etc for changing newline setting at start of pattern.
1341    Version 7.2 19-Jun-07
1342    ---------------------
1344     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1345        which is apparently normally available under Windows.
1347     2. Re-jig the pcregrep tests with different newline settings in an attempt
1348        to make them independent of the local environment's newline setting.
1350     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1352     4. Some of the "internals" tests were previously cut out when the link size
1353        was not 2, because the output contained actual offsets. The recent new
1354        "Z" feature of pcretest means that these can be cut out, making the tests
1355        usable with all link sizes.
1357     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1358        stack recursion. This gives a massive performance boost under BSD, but just
1359        a small improvement under Linux. However, it saves one field in the frame
1360        in all cases.
1362     6. Added more features from the forthcoming Perl 5.10:
1364        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1365            recursion call. It refers to the nth most recently opened parentheses.
1367        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1368            to be opened parentheses.
1370        (c) Conditions that refer to capturing parentheses can be specified
1371            relatively, for example, (?(-2)... or (?(+3)...
1373        (d) \K resets the start of the current match so that everything before
1374            is not part of it.
1376        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1378        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1379            reference syntax.
1381        (g) (?| introduces a group in which the numbering of parentheses in each
1382            alternative starts with the same number.
1384        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1386     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1389     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1390        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1391        for detecting groups that can match an empty string.
1393     9. A pattern with a very large number of alternatives (more than several
1394        hundred) was running out of internal workspace during the pre-compile
1395        phase, where pcre_compile() figures out how much memory will be needed. A
1396        bit of new cunning has reduced the workspace needed for groups with
1397        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1398        workspace instead of running out of the 4096 that are available.
1400    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1402    11. Applied patch from Google to remove an optimization that didn't quite work.
1403        The report of the bug said:
1405          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1406          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1407          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1409    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1410        it matched the wrong number of bytes.
1413    Version 7.1 24-Apr-07
1414    ---------------------
1416     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1417        that is more "standard", making use of automake and other Autotools. There
1418        is some re-arrangement of the files and adjustment of comments consequent
1419        on this.
1421     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1422        for recursive directory scanning broke on some systems because the files
1423        are not scanned in any specific order and on different systems the order
1424        was different. A call to "sort" has been inserted into RunGrepTest for the
1425        approprate test as a short-term fix. In the longer term there may be an
1426        alternative.
1428     3. I had an email from Eric Raymond about problems translating some of PCRE's
1429        man pages to HTML (despite the fact that I distribute HTML pages, some
1430        people do their own conversions for various reasons). The problems
1431        concerned the use of low-level troff macros .br and .in. I have therefore
1432        removed all such uses from the man pages (some were redundant, some could
1433        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1434        HTML has been updated to handle .nf/.fi and to complain if it encounters
1435        .br or .in.
1437     4. Updated comments in configure.ac that get placed in config.h.in and also
1438        arranged for config.h to be included in the distribution, with the name
1439        config.h.generic, for the benefit of those who have to compile without
1440        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1442     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1443        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1444        makevp.bat for the current PCRE, using the additional files
1445        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1447     6. A Windows user reported a minor discrepancy with test 2, which turned out
1448        to be caused by a trailing space on an input line that had got lost in his
1449        copy. The trailing space was an accident, so I've just removed it.
1451     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1452        that is needed.
1454     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1455        as "const" (a) because they are and (b) because it helps the PHP
1456        maintainers who have recently made a script to detect big data structures
1457        in the php code that should be moved to the .rodata section. I remembered
1458        to update Builducptable as well, so it won't revert if ucptable.h is ever
1459        re-created.
1461     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1462        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1463        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1464        support is not required. This saves 1.5-2K of code, which is important in
1465        some applications.
1467        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1468        so as not to refer to the tables, even though these functions will never be
1469        called when UTF-8 support is disabled. Otherwise there are problems with a
1470        shared library.
1472    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1474        (a) It was defining its arguments as char * instead of void *.
1476        (b) It was assuming that all moves were upwards in memory; this was true
1477            a long time ago when I wrote it, but is no longer the case.
1479        The emulated memove() is provided for those environments that have neither
1480        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1481        is clearly not the case, as these two bugs were recently reported.
1483    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1484        and Detrail to create the HTML documentation, the .txt form of the man
1485        pages, and it removes trailing spaces from listed files. It also creates
1486        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1487        case, it wraps all the #defines with #ifndefs. This script should be run
1488        before "make dist".
1490    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1491        with Unicode property support.
1493        (a) For a maximizing quantifier, if the two different cases of the
1494            character were of different lengths in their UTF-8 codings (there are
1495            some cases like this - I found 11), and the matching function had to
1496            back up over a mixture of the two cases, it incorrectly assumed they
1497            were both the same length.
1499        (b) When PCRE was configured to use the heap rather than the stack for
1500            recursion during matching, it was not correctly preserving the data for
1501            the other case of a UTF-8 character when checking ahead for a match
1502            while processing a minimizing repeat. If the check also involved
1503            matching a wide character, but failed, corruption could cause an
1504            erroneous result when trying to check for a repeat of the original
1505            character.
1507    13. Some tidying changes to the testing mechanism:
1509        (a) The RunTest script now detects the internal link size and whether there
1510            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1511            values substituted by "configure". (The RunGrepTest script already did
1512            this for UTF-8.) The configure.ac script no longer substitutes the
1513            relevant variables.
1515        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1516            with length and offset values. This means that the output is different
1517            for different internal link sizes. Test 2 is skipped for link sizes
1518            other than 2 because of this, bypassing the problem. Unfortunately,
1519            there was also a test in test 3 (the locale tests) that used /B and
1520            failed for link sizes other than 2. Rather than cut the whole test out,
1521            I have added a new /Z option to pcretest that replaces the length and
1522            offset values with spaces. This is now used to make test 3 independent
1523            of link size. (Test 2 will be tidied up later.)
1525    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1526        segmentation fault instead of returning the appropriate error message.
1528    15. In multiline mode when the newline sequence was set to "any", the pattern
1529        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1530        This doesn't seem right; it now treats the CRLF combination as the line
1531        ending, and so does not match in that case. It's only a pattern such as ^$
1532        that would hit this one: something like ^ABC$ would have failed after \r
1533        and then tried again after \r\n.
1535    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1536        in an attempt to make files that differ only in their line terminators
1537        compare equal. This works on Linux.
1539    17. Under certain error circumstances pcregrep might try to free random memory
1540        as it exited. This is now fixed, thanks to valgrind.
1542    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1543        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1544        was because its rules for how to advance for /g after matching an empty
1545        string at the end of a line did not allow for this case. They now check for
1546        it specially.
1548    20. pcretest is supposed to handle patterns and data of any length, by
1549        extending its buffers when necessary. It was getting this wrong when the
1550        buffer for a data line had to be extended.
1552    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1553        CRLF as a newline sequence.
1555    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1556        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1557        I have nevertheless tidied it up.
1559    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1561    24. Added a man page for pcre-config.
1564    Version 7.0 19-Dec-06
1565    ---------------------
1567     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1568        moving to gcc 4.1.1.
1570     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1571        sys/time.h, which is documented as needed for this function. It doesn't
1572        seem to matter on Linux, but it showed up on some releases of OS X.
1574     3. It seems that there are systems where bytes whose values are greater than
1575        127 match isprint() in the "C" locale. The "C" locale should be the
1576        default when a C program starts up. In most systems, only ASCII printing
1577        characters match isprint(). This difference caused the output from pcretest
1578        to vary, making some of the tests fail. I have changed pcretest so that:
1580        (a) When it is outputting text in the compiled version of a pattern, bytes
1581            other than 32-126 are always shown as hex escapes.
1583        (b) When it is outputting text that is a matched part of a subject string,
1584            it does the same, unless a different locale has been set for the match
1585            (using the /L modifier). In this case, it uses isprint() to decide.
1587     4. Fixed a major bug that caused incorrect computation of the amount of memory
1588        required for a compiled pattern when options that changed within the
1589        pattern affected the logic of the preliminary scan that determines the
1590        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1591        that the computed length was too small. The symptoms of this bug were
1592        either the PCRE error "internal error: code overflow" from pcre_compile(),
1593        or a glibc crash with a message such as "pcretest: free(): invalid next
1594        size (fast)". Examples of patterns that provoked this bug (shown in
1595        pcretest format) are:
1597          /(?-x: )/x
1598          /(?x)(?-x: \s*#\s*)/
1599          /((?i)[\x{c0}])/8
1600          /(?i:[\x{c0}])/8
1602        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1603        is now done differently.
1605     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1606        wrapper classes; (b) implement a new function in the C++ scanner that is
1607        more efficient than the old way of doing things because it avoids levels of
1608        recursion in the regex matching; (c) add a paragraph to the documentation
1609        for the FullMatch() function.
1611     6. The escape sequence \n was being treated as whatever was defined as
1612        "newline". Not only was this contrary to the documentation, which states
1613        that \n is character 10 (hex 0A), but it also went horribly wrong when
1614        "newline" was defined as CRLF. This has been fixed.
1616     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1617        was being set to -1 for the "end of line" case (supposedly a value that no
1618        character can have). Though this value is never used (the check for end of
1619        line is "zero bytes in current character"), it caused compiler complaints.
1620        I've changed it to 0xffffffff.
1622     8. In pcre_version.c, the version string was being built by a sequence of
1623        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1624        string (as it is for production releases) called a macro with an empty
1625        argument. The C standard says the result of this is undefined. The gcc
1626        compiler treats it as an empty string (which was what was wanted) but it is
1627        reported that Visual C gives an error. The source has been hacked around to
1628        avoid this problem.
1630     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1631        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1632        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1633        of them did).
1635    10. Originally, pcretest opened its input and output without "b"; then I was
1636        told that "b" was needed in some environments, so it was added for release
1637        5.0 to both the input and output. (It makes no difference on Unix-like
1638        systems.) Later I was told that it is wrong for the input on Windows. I've
1639        now abstracted the modes into two macros, to make it easier to fiddle with
1640        them, and removed "b" from the input mode under Windows.
1642    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1644    12. Added -help and --help to pcretest as an official way of being reminded
1645        of the options.
1647    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1648        and pcrecpp.cc because they annoy compilers at high warning levels.
1650    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1652    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1653        scripts are not C programs :-) and which was not noticed because it works
1654        on Linux.
1656    16. pcretest is supposed to handle any length of pattern and data line (as one
1657        line or as a continued sequence of lines) by extending its input buffer if
1658        necessary. This feature was broken for very long pattern lines, leading to
1659        a string of junk being passed to pcre_compile() if the pattern was longer
1660        than about 50K.
1662    17. I have done a major re-factoring of the way pcre_compile() computes the
1663        amount of memory needed for a compiled pattern. Previously, there was code
1664        that made a preliminary scan of the pattern in order to do this. That was
1665        OK when PCRE was new, but as the facilities have expanded, it has become
1666        harder and harder to keep it in step with the real compile phase, and there
1667        have been a number of bugs (see for example, 4 above). I have now found a
1668        cunning way of running the real compile function in a "fake" mode that
1669        enables it to compute how much memory it would need, while actually only
1670        ever using a few hundred bytes of working memory and without too many
1671        tests of the mode. This should make future maintenance and development
1672        easier. A side effect of this work is that the limit of 200 on the nesting
1673        depth of parentheses has been removed (though this was never a serious
1674        limitation, I suspect). However, there is a downside: pcre_compile() now
1675        runs more slowly than before (30% or more, depending on the pattern). I
1676        hope this isn't a big issue. There is no effect on runtime performance.
1678    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1679        newline (only possible for the last line of a file) and it was a
1680        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1682    19. Added additional timing features to pcretest. (1) The -tm option now times
1683        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1684        separate command line item, by a number that specifies the number of
1685        repeats to use when timing. The default is 50000; this gives better
1686        precision, but takes uncomfortably long for very large patterns.
1688    20. Extended pcre_study() to be more clever in cases where a branch of a
1689        subpattern has no definite first character. For example, (a*|b*)[cd] would
1690        previously give no result from pcre_study(). Now it recognizes that the
1691        first character must be a, b, c, or d.
1693    21. There was an incorrect error "recursive call could loop indefinitely" if
1694        a subpattern (or the entire pattern) that was being tested for matching an
1695        empty string contained only one non-empty item after a nested subpattern.
1696        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1697        incorrectly, because the \d was being skipped in the check.
1699    22. The pcretest program now has a new pattern option /B and a command line
1700        option -b, which is equivalent to adding /B to every pattern. This causes
1701        it to show the compiled bytecode, without the additional information that
1702        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1703        is the same as /B/I).
1705    23. A new optimization is now able automatically to treat some sequences such
1706        as a*b as a*+b. More specifically, if something simple (such as a character
1707        or a simple class like \d) has an unlimited quantifier, and is followed by
1708        something that cannot possibly match the quantified thing, the quantifier
1709        is automatically "possessified".
1711    24. A recursive reference to a subpattern whose number was greater than 39
1712        went wrong under certain circumstances in UTF-8 mode. This bug could also
1713        have affected the operation of pcre_study().
1715    25. Realized that a little bit of performance could be had by replacing
1716        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1718    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1720    27. Possessive quantifiers such as a++ were previously implemented by turning
1721        them into atomic groups such as ($>a+). Now they have their own opcodes,
1722        which improves performance. This includes the automatically created ones
1723        from 23 above.
1725    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1726        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1727        the first matched character to be a colon. This applied both to named and
1728        numbered groups.
1730    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1732    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1733        building PCRE on Windows easier, so I have included it in the distribution.
1735    31. There is now a check in pcretest against a ridiculously large number being
1736        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1737        loop, the loop is abandoned.
1739    32. Forward references to subpatterns in conditions such as (?(2)...) where
1740        subpattern 2 is defined later cause pcre_compile() to search forwards in
1741        the pattern for the relevant set of parentheses. This search went wrong
1742        when there were unescaped parentheses in a character class, parentheses
1743        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1745    33. "Subroutine" calls and backreferences were previously restricted to
1746        referencing subpatterns earlier in the regex. This restriction has now
1747        been removed.
1749    34. Added a number of extra features that are going to be in Perl 5.10. On the
1750        whole, these are just syntactic alternatives for features that PCRE had
1751        previously implemented using the Python syntax or my own invention. The
1752        other formats are all retained for compatibility.
1754        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1755            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1756            also .NET compatible.
1758        (b) A recursion or subroutine call to a named group can now be defined as
1759            (?&name) as well as (?P>name).
1761        (c) A backreference to a named group can now be defined as \k<name> or
1762            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1763            5.10, are also .NET compatible.
1765        (d) A conditional reference to a named group can now use the syntax
1766            (?(<name>) or (?('name') as well as (?(name).
1768        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1769            groups (named and numbered) that are never evaluated inline, but can be
1770            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1771            is always false. There may be only one alternative in such a group.
1773        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1774            as the simple (?(R). The condition is true only if the most recent
1775            recursion is that of the given number or name. It does not search out
1776            through the entire recursion stack.
1778        (g) The escape \gN or \g{N} has been added, where N is a positive or
1779            negative number, specifying an absolute or relative reference.
1781    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1782        some "unreachable code" warnings.
1784    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1785        things, this adds five new scripts.
1787    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1788        There were also incompatibilities regarding the handling of \Q..\E inside
1789        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1790        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1792    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1793        matches an empty string, and forcibly breaks the loop. There were bugs in
1794        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1795        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1796        separate and independent bugs (that affected different cases) have been
1797        fixed.
1799    39. Refactored the code to abolish the use of different opcodes for small
1800        capturing bracket numbers. This is a tidy that I avoided doing when I
1801        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1802        The new approach is not only tidier, it makes it possible to reduce the
1803        memory needed to fix the previous bug (38).
1805    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1806        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1807        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1808        mode.
1810    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1811        report.
1813    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1814        copy construction and assignment in the C++ wrapper.
1816    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1817        couple of bugs that could have given wrong results in the "--newline=crlf"
1818        case.
1820    44. Added a number of casts and did some reorganization of signed/unsigned int
1821        variables following suggestions from Dair Grant. Also renamed the variable
1822        "this" as "item" because it is a C++ keyword.
1824    45. Arranged for dftables to add
1826          #include "pcre_internal.h"
1828        to pcre_chartables.c because without it, gcc 4.x may remove the array
1829        definition from the final binary if PCRE is built into a static library and
1830        dead code stripping is activated.
1832    46. For an unanchored pattern, if a match attempt fails at the start of a
1833        newline sequence, and the newline setting is CRLF or ANY, and the next two
1834        characters are CRLF, advance by two characters instead of one.
1837    Version 6.7 04-Jul-06
1838    ---------------------
1840     1. In order to handle tests when input lines are enormously long, pcretest has
1841        been re-factored so that it automatically extends its buffers when
1842        necessary. The code is crude, but this _is_ just a test program. The
1843        default size has been increased from 32K to 50K.
1845     2. The code in pcre_study() was using the value of the re argument before
1846        testing it for NULL. (Of course, in any sensible call of the function, it
1847        won't be NULL.)
1849     3. The memmove() emulation function in pcre_internal.h, which is used on
1850        systems that lack both memmove() and bcopy() - that is, hardly ever -
1851        was missing a "static" storage class specifier.
1853     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1854        containing an extended class (one that cannot be represented by a bitmap
1855        because it contains high-valued characters or Unicode property items, e.g.
1856        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1857        pattern, but PCRE should not loop if you do not (it no longer does).
1858        [Detail: two cases were found: (a) a repeated subpattern containing an
1859        extended class; (b) a recursive reference to a subpattern that followed a
1860        previous extended class. It wasn't skipping over the extended class
1861        correctly when UTF-8 mode was not set.]
1863     5. A negated single-character class was not being recognized as fixed-length
1864        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1865        compile error "lookbehind assertion is not fixed length".
1867     6. The RunPerlTest auxiliary script was showing an unexpected difference
1868        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1869        write a Perl script that can interpret lines of an input file either as
1870        byte characters or as UTF-8, which is what "perltest" was being required to
1871        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1872        can't do is switch easily at run time between having the "use utf8;" pragma
1873        or not. In the end, I fudged it by using the RunPerlTest script to insert
1874        "use utf8;" explicitly for the UTF-8 tests.
1876     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1877        the end of the subject string, contrary to the documentation and to what
1878        Perl does. This was true of both matching functions. Now it matches only at
1879        the start of the subject and immediately after *internal* newlines.
1881     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1882        a pointer to an int instead of a pointer to an unsigned long int. This
1883        caused problems on 64-bit systems.
1885     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1886        instance of the 'standard' template library not being so standard".
1888    10. There was no check on the number of named subpatterns nor the maximum
1889        length of a subpattern name. The product of these values is used to compute
1890        the size of the memory block for a compiled pattern. By supplying a very
1891        long subpattern name and a large number of named subpatterns, the size
1892        computation could be caused to overflow. This is now prevented by limiting
1893        the length of names to 32 characters, and the number of named subpatterns
1894        to 10,000.
1896    11. Subpatterns that are repeated with specific counts have to be replicated in
1897        the compiled pattern. The size of memory for this was computed from the
1898        length of the subpattern and the repeat count. The latter is limited to
1899        65535, but there was no limit on the former, meaning that integer overflow
1900        could in principle occur. The compiled length of a repeated subpattern is
1901        now limited to 30,000 bytes in order to prevent this.
1903    12. Added the optional facility to have named substrings with the same name.
1905    13. Added the ability to use a named substring as a condition, using the
1906        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1907        are numbers (not recommended). Forward references are permitted.
1909    14. Added forward references in named backreferences (if you see what I mean).
1911    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1912        pattern could run off the end of the subject. For example, the pattern
1913        "(?s)(.{1,5})"8 did this with the subject "ab".
1915    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1916        PCRE_CASELESS was set when matching characters that were quantified with ?
1917        or *.
1919    17. A character class other than a single negated character that had a minimum
1920        but no maximum quantifier - for example [ab]{6,} - was not handled
1921        correctly by pce_dfa_exec(). It would match only one character.
1923    18. A valid (though odd) pattern that looked like a POSIX character
1924        class but used an invalid character after [ (for example [[,abc,]]) caused
1925        pcre_compile() to give the error "Failed: internal error: code overflow" or
1926        in some cases to crash with a glibc free() error. This could even happen if
1927        the pattern terminated after [[ but there just happened to be a sequence of
1928        letters, a binary zero, and a closing ] in the memory that followed.
1930    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1931        over the years. Originally (before any Unicode support), just the bottom 8
1932        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1933        output from "man perlunicode" includes this:
1935          The regular expression compiler produces polymorphic opcodes.  That
1936          is, the pattern adapts to the data and automatically switches to
1937          the Unicode character scheme when presented with Unicode data--or
1938          instead uses a traditional byte scheme when presented with byte
1939          data.
1941        Sadly, a wide octal escape does not cause a switch, and in a string with
1942        no other multibyte characters, these octal escapes are treated as before.
1943        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1944        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1945        Unicode string.
1947        I have not perpetrated such confusion in PCRE. Up till now, it took just
1948        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1949        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1950        translate to the appropriate multibyte character.
1952    29. Applied some refactoring to reduce the number of warnings from Microsoft
1953        and Borland compilers. This has included removing the fudge introduced
1954        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1955        a warning about an unused variable.
1957    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1958        characters since release 4.0, because Perl (from release 5.004) does not.
1959        [Or at least, is documented not to: some releases seem to be in conflict
1960        with the documentation.] However, when a pattern was studied with
1961        pcre_study() and all its branches started with \s, PCRE still included VT
1962        as a possible starting character. Of course, this did no harm; it just
1963        caused an unnecessary match attempt.
1965    22. Removed a now-redundant internal flag bit that recorded the fact that case
1966        dependency changed within the pattern. This was once needed for "required
1967        byte" processing, but is no longer used. This recovers a now-scarce options
1968        bit. Also moved the least significant internal flag bit to the most-
1969        significant bit of the word, which was not previously used (hangover from
1970        the days when it was an int rather than a uint) to free up another bit for
1971        the future.
1973    23. Added support for CRLF line endings as well as CR and LF. As well as the
1974        default being selectable at build time, it can now be changed at runtime
1975        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1976        specify that it is scanning data with non-default line endings.
1978    24. Changed the definition of CXXLINK to make it agree with the definition of
1979        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1981    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1982        recursions. This makes a big different to stack usage for some patterns.
1984    26. If a subpattern containing a named recursion or subroutine reference such
1985        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1986        the space required for the compiled pattern went wrong and gave too small a
1987        value. Depending on the environment, this could lead to "Failed: internal
1988        error: code overflow at offset 49" or "glibc detected double free or
1989        corruption" errors.
1991    27. Applied patches from Google (a) to support the new newline modes and (b) to
1992        advance over multibyte UTF-8 characters in GlobalReplace.
1994    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1995        difference for some implementation of PCRE in some Windows version.
1997    29. Added some extra testing facilities to pcretest:
1999        \q<number>   in a data line sets the "match limit" value
2000        \Q<number>   in a data line sets the "match recursion limt" value
2001        -S <number>  sets the stack size, where <number> is in megabytes
2003        The -S option isn't available for Windows.
2006    Version 6.6 06-Feb-06
2007    ---------------------
2009     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
2010        in pcreposix.h. I have copied the definition from pcre.h.
2012     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
2013        because pcre.h is no longer a built file.
2015     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
2016        not normally included in the compiled code.
2019    Version 6.5 01-Feb-06
2020    ---------------------
2022     1. When using the partial match feature with pcre_dfa_exec(), it was not
2023        anchoring the second and subsequent partial matches at the new starting
2024        point. This could lead to incorrect results. For example, with the pattern
2025        /1234/, partially matching against "123" and then "a4" gave a match.
2027     2. Changes to pcregrep:
2029        (a) All non-match returns from pcre_exec() were being treated as failures
2030            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
2031            error message is output. Some extra information is given for the
2032            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
2033            probably the only errors that are likely to be caused by users (by
2034            specifying a regex that has nested indefinite repeats, for instance).
2035            If there are more than 20 of these errors, pcregrep is abandoned.
2037        (b) A binary zero was treated as data while matching, but terminated the
2038            output line if it was written out. This has been fixed: binary zeroes
2039            are now no different to any other data bytes.
2041        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
2042            used to set a locale for matching. The --locale=xxxx long option has
2043            been added (no short equivalent) to specify a locale explicitly on the
2044            pcregrep command, overriding the environment variables.
2046        (d) When -B was used with -n, some line numbers in the output were one less
2047            than they should have been.
2049        (e) Added the -o (--only-matching) option.
2051        (f) If -A or -C was used with -c (count only), some lines of context were
2052            accidentally printed for the final match.
2054        (g) Added the -H (--with-filename) option.
2056        (h) The combination of options -rh failed to suppress file names for files
2057            that were found from directory arguments.
2059        (i) Added the -D (--devices) and -d (--directories) options.
2061        (j) Added the -F (--fixed-strings) option.
2063        (k) Allow "-" to be used as a file name for -f as well as for a data file.
2065        (l) Added the --colo(u)r option.
2067        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
2068            is not present by default.
2070     3. A nasty bug was discovered in the handling of recursive patterns, that is,
2071        items such as (?R) or (?1), when the recursion could match a number of
2072        alternatives. If it matched one of the alternatives, but subsequently,
2073        outside the recursion, there was a failure, the code tried to back up into
2074        the recursion. However, because of the way PCRE is implemented, this is not
2075        possible, and the result was an incorrect result from the match.
2077        In order to prevent this happening, the specification of recursion has
2078        been changed so that all such subpatterns are automatically treated as
2079        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
2081     4. I had overlooked the fact that, in some locales, there are characters for
2082        which isalpha() is true but neither isupper() nor islower() are true. In
2083        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
2084        and ordfeminine) are like this. This affected the treatment of \w and \W
2085        when they appeared in character classes, but not when they appeared outside
2086        a character class. The bit map for "word" characters is now created
2087        separately from the results of isalnum() instead of just taking it from the
2088        upper, lower, and digit maps. (Plus the underscore character, of course.)
2090     5. The above bug also affected the handling of POSIX character classes such as
2091        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
2092        permanent tables. Instead, the bit maps for such a class were previously
2093        created as the appropriate unions of the upper, lower, and digit bitmaps.
2094        Now they are created by subtraction from the [[:word:]] class, which has
2095        its own bitmap.
2097     6. The [[:blank:]] character class matches horizontal, but not vertical space.
2098        It is created by subtracting the vertical space characters (\x09, \x0a,
2099        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
2100        subtraction was done in the overall bitmap for a character class, meaning
2101        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
2102        be recognized. This bug has been fixed.
2104     7. Patches from the folks at Google:
2106          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
2107          real life, but is still worth protecting against".
2109          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
2110          regular expressions".
2112          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
2113          have it.
2115          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
2116          "configure" and the latter not, in order to fix a problem somebody had
2117          with compiling the Arg class on HP-UX.
2119          (e) Improve the error-handling of the C++ wrapper a little bit.
2121          (f) New tests for checking recursion limiting.
2123     8. The pcre_memmove() function, which is used only if the environment does not
2124        have a standard memmove() function (and is therefore rarely compiled),
2125        contained two bugs: (a) use of int instead of size_t, and (b) it was not
2126        returning a result (though PCRE never actually uses the result).
2128     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
2129        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
2130        returned instead of calling malloc() with an overflowing number that would
2131        most likely cause subsequent chaos.
2133    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
2135    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
2136        with this option is matched, the nmatch and pmatch options of regexec() are
2137        ignored.
2139    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
2140        provided in case anyone wants to the the POSIX interface with UTF-8
2141        strings.
2143    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
2144        C++ linking (needed for some HP-UX environments).
2146    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
2147        (unused parameter) and in the pcre_printint() function (omitted "default"
2148        switch label when the default is to do nothing).
2150    15. Added some code to make it possible, when PCRE is compiled as a C++
2151        library, to replace subject pointers for pcre_exec() with a smart pointer
2152        class, thus making it possible to process discontinuous strings.
2154    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
2155        much the same function. They were added by different people who were trying
2156        to make PCRE easy to compile on non-Unix systems. It has been suggested
2157        that PCRE_EXPORT be abolished now that there is more automatic apparatus
2158        for compiling on Windows systems. I have therefore replaced it with
2159        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
2160        defaults to "extern" for C or "extern C" for C++, which works fine on
2161        Unix-like systems. It is now possible to override the value of PCRE_DATA_
2162        SCOPE with something explicit in config.h. In addition:
2164        (a) pcreposix.h still had just "extern" instead of either of these macros;
2165            I have replaced it with PCRE_DATA_SCOPE.
2167        (b) Functions such as _pcre_xclass(), which are internal to the library,
2168            but external in the C sense, all had PCRE_EXPORT in their definitions.
2169            This is apparently wrong for the Windows case, so I have removed it.
2170            (It makes no difference on Unix-like systems.)
2172    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
2173        of recursive calls to match(). This is different to MATCH_LIMIT because
2174        that limits the total number of calls to match(), not all of which increase
2175        the depth of recursion. Limiting the recursion depth limits the amount of
2176        stack (or heap if NO_RECURSE is set) that is used. The default can be set
2177        when PCRE is compiled, and changed at run time. A patch from Google adds
2178        this functionality to the C++ interface.
2180    18. Changes to the handling of Unicode character properties:
2182        (a) Updated the table to Unicode 4.1.0.
2184        (b) Recognize characters that are not in the table as "Cn" (undefined).
2186        (c) I revised the way the table is implemented to a much improved format
2187            which includes recognition of ranges. It now supports the ranges that
2188            are defined in UnicodeData.txt, and it also amalgamates other
2189            characters into ranges. This has reduced the number of entries in the
2190            table from around 16,000 to around 3,000, thus reducing its size
2191            considerably. I realized I did not need to use a tree structure after
2192            all - a binary chop search is just as efficient. Having reduced the
2193            number of entries, I extended their size from 6 bytes to 8 bytes to
2194            allow for more data.
2196        (d) Added support for Unicode script names via properties such as \p{Han}.
2198    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
2199        matching that character.
2201    20. When matching a repeated Unicode property with a minimum greater than zero,
2202        (for example \pL{2,}), PCRE could look past the end of the subject if it
2203        reached it while seeking the minimum number of characters. This could
2204        happen only if some of the characters were more than one byte long, because
2205        there is a check for at least the minimum number of bytes.
2207    21. Refactored the implementation of \p and \P so as to be more general, to
2208        allow for more different types of property in future. This has changed the
2209        compiled form incompatibly. Anybody with saved compiled patterns that use
2210        \p or \P will have to recompile them.
2212    22. Added "Any" and "L&" to the supported property types.
2214    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
2215        but give a compile time error if the value is greater than 0xff.
2217    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
2218        accidentally not being installed or uninstalled.
2220    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2221        made were to insert the current release number. This seemed silly, because
2222        it made things harder for people building PCRE on systems that don't run
2223        "configure". I have turned pcre.h into a distributed file, no longer built
2224        by "configure", with the version identification directly included. There is
2225        no longer a pcre.h.in file.
2227        However, this change necessitated a change to the pcre-config script as
2228        well. It is built from pcre-config.in, and one of the substitutions was the
2229        release number. I have updated configure.ac so that ./configure now finds
2230        the release number by grepping pcre.h.
2232    26. Added the ability to run the tests under valgrind.
2235    Version 6.4 05-Sep-05
2236    ---------------------
2238     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2239        "--" to be printed when multiple files were scanned, even when none of the
2240        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2241        consider it to be a bug, and have restored the previous behaviour.
2243     2. A couple of code tidies to get rid of compiler warnings.
2245     3. The pcretest program used to cheat by referring to symbols in the library
2246        whose names begin with _pcre_. These are internal symbols that are not
2247        really supposed to be visible externally, and in some environments it is
2248        possible to suppress them. The cheating is now confined to including
2249        certain files from the library's source, which is a bit cleaner.
2251     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2252        file's purpose clearer.
2254     5. Reorganized pcre_ucp_findchar().
2257    Version 6.3 15-Aug-05
2258    ---------------------
2260     1. The file libpcre.pc.in did not have general read permission in the tarball.
2262     2. There were some problems when building without C++ support:
2264        (a) If C++ support was not built, "make install" and "make test" still
2265            tried to test it.
2267        (b) There were problems when the value of CXX was explicitly set. Some
2268            changes have been made to try to fix these, and ...
2270        (c) --disable-cpp can now be used to explicitly disable C++ support.
2272        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2273            backslash in a target when C++ was disabled. This confuses some
2274            versions of "make", apparently. Using an intermediate variable solves
2275            this. (Same for CPP_LOBJ.)
2277     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2278        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2279        necessary on certain architectures.
2281     4. Added a setting of -export-symbols-regex to the link command to remove
2282        those symbols that are exported in the C sense, but actually are local
2283        within the library, and not documented. Their names all begin with
2284        "_pcre_". This is not a perfect job, because (a) we have to except some
2285        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2286        available (and never for static libraries). I have made a note to try to
2287        find a way round (a) in the future.
2290    Version 6.2 01-Aug-05
2291    ---------------------
2293     1. There was no test for integer overflow of quantifier values. A construction
2294        such as {1111111111111111} would give undefined results. What is worse, if
2295        a minimum quantifier for a parenthesized subpattern overflowed and became
2296        negative, the calculation of the memory size went wrong. This could have
2297        led to memory overwriting.
2299     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2301     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2302        operating environments where this matters.
2304     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2305        PCRE options from within the C++ wrapper.
2307     5. Named capturing subpatterns were not being correctly counted when a pattern
2308        was compiled. This caused two problems: (a) If there were more than 100
2309        such subpatterns, the calculation of the memory needed for the whole
2310        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2311        back references of the form \12, where the number was greater than 9, were
2312        not recognized as back references, even though there were sufficient
2313        previous subpatterns.
2315     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2316        versions of gcc, e.g. 2.95.4.
2319    Version 6.1 21-Jun-05
2320    ---------------------
2322     1. There was one reference to the variable "posix" in pcretest.c that was not
2323        surrounded by "#if !defined NOPOSIX".
2325     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2326        the cross-check on the old pcre_info() function, for the benefit of the
2327        cut-down version of PCRE that is currently imported into Exim.
2329     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2330        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2331        patterns that start (?i) but I don't think that matters. The use of (?i) is
2332        just an example; this all applies to the other options as well.
2334     4. Since libtool seems to echo the compile commands it is issuing, the output
2335        from "make" can be reduced a bit by putting "@" in front of each libtool
2336        compile command.
2338     5. Patch from the folks at Google for configure.in to be a bit more thorough
2339        in checking for a suitable C++ installation before trying to compile the
2340        C++ stuff. This should fix a reported problem when a compiler was present,
2341        but no suitable headers.
2343     6. The man pages all had just "PCRE" as their title. I have changed them to
2344        be the relevant file name. I have also arranged that these names are
2345        retained in the file doc/pcre.txt, which is a concatenation in text format
2346        of all the man pages except the little individual ones for each function.
2348     7. The NON-UNIX-USE file had not been updated for the different set of source
2349        files that come with release 6. I also added a few comments about the C++
2350        wrapper.
2353    Version 6.0 07-Jun-05
2354    ---------------------
2356     1. Some minor internal re-organization to help with my DFA experiments.
2358     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2359        didn't matter for the library itself when fully configured, but did matter
2360        when compiling without UCP support, or within Exim, where the ucp files are
2361        not imported.
2363     3. Refactoring of the library code to split up the various functions into
2364        different source modules. The addition of the new DFA matching code (see
2365        below) to a single monolithic source would have made it really too
2366        unwieldy, quite apart from causing all the code to be include in a
2367        statically linked application, when only some functions are used. This is
2368        relevant even without the DFA addition now that patterns can be compiled in
2369        one application and matched in another.
2371        The downside of splitting up is that there have to be some external
2372        functions and data tables that are used internally in different modules of
2373        the library but which are not part of the API. These have all had their
2374        names changed to start with "_pcre_" so that they are unlikely to clash
2375        with other external names.
2377     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2378        a different (DFA) algorithm. Although it is slower than the original
2379        function, it does have some advantages for certain types of matching
2380        problem.
2382     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2383        including restarting after a partial match.
2385     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2386        defined when compiling for Windows was sent to me. I have put it into the
2387        code, though I have no means of testing or verifying it.
2389     7. Added the pcre_refcount() auxiliary function.
2391     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2392        match before or at the first newline in the subject string. In pcretest,
2393        the /f option on a pattern can be used to set this.
2395     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2396        would behave wrongly. This has been present in PCRE since release 4.0.
2398    10. A number of changes to the pcregrep command:
2400        (a) Refactored how -x works; insert ^(...)$ instead of setting
2401            PCRE_ANCHORED and checking the length, in preparation for adding
2402            something similar for -w.
2404        (b) Added the -w (match as a word) option.
2406        (c) Refactored the way lines are read and buffered so as to have more
2407            than one at a time available.
2409        (d) Implemented a pcregrep test script.
2411        (e) Added the -M (multiline match) option. This allows patterns to match
2412            over several lines of the subject. The buffering ensures that at least
2413            8K, or the rest of the document (whichever is the shorter) is available
2414            for matching (and similarly the previous 8K for lookbehind assertions).
2416        (f) Changed the --help output so that it now says
2418              -w, --word-regex(p)
2420            instead of two lines, one with "regex" and the other with "regexp"
2421            because that confused at least one person since the short forms are the
2422            same. (This required a bit of code, as the output is generated
2423            automatically from a table. It wasn't just a text change.)
2425        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2426            option but starts with a hyphen. Could be a pattern or a path name
2427            starting with a hyphen, for instance.
2429        (h) "-" can be given as a file name to represent stdin.
2431        (i) When file names are being printed, "(standard input)" is used for
2432            the standard input, for compatibility with GNU grep. Previously
2433            "<stdin>" was used.
2435        (j) The option --label=xxx can be used to supply a name to be used for
2436            stdin when file names are being printed. There is no short form.
2438        (k) Re-factored the options decoding logic because we are going to add
2439            two more options that take data. Such options can now be given in four
2440            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2442        (l) Added the -A, -B, and -C options for requesting that lines of context
2443            around matches be printed.
2445        (m) Added the -L option to print the names of files that do not contain
2446            any matching lines, that is, the complement of -l.
2448        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2449            continue to scan other files.
2451        (o) The -s option was incorrectly implemented. For compatibility with other
2452            greps, it now suppresses the error message for a non-existent or non-
2453            accessible file (but not the return code). There is a new option called
2454            -q that suppresses the output of matching lines, which was what -s was
2455            previously doing.
2457        (p) Added --include and --exclude options to specify files for inclusion
2458            and exclusion when recursing.
2460    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2461        Hopefully, it now does.
2463    12. Missing cast in pcre_study().
2465    13. Added an "uninstall" target to the makefile.
2467    14. Replaced "extern" in the function prototypes in Makefile.in with
2468        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2469        world, but is set differently for Windows.
2471    15. Added a second compiling function called pcre_compile2(). The only
2472        difference is that it has an extra argument, which is a pointer to an
2473        integer error code. When there is a compile-time failure, this is set
2474        non-zero, in addition to the error test pointer being set to point to an
2475        error message. The new argument may be NULL if no error number is required
2476        (but then you may as well call pcre_compile(), which is now just a
2477        wrapper). This facility is provided because some applications need a
2478        numeric error indication, but it has also enabled me to tidy up the way
2479        compile-time errors are handled in the POSIX wrapper.
2481    16. Added VPATH=.libs to the makefile; this should help when building with one
2482        prefix path and installing with another. (Or so I'm told by someone who
2483        knows more about this stuff than I do.)
2485    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2486        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2487        match everything, including newlines. This is not POSIX-compatible, but
2488        somebody wanted the feature. From pcretest it can be activated by using
2489        both the P and the s flags.
2491    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2493    19. libpcre.pc was being incorrectly installed as executable.
2495    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2496        it now also looks for '\r' so that it will work unmodified on Windows.
2498    21. Added Google's contributed C++ wrapper to the distribution.
2500    22. Added some untidy missing memory free() calls in pcretest, to keep
2501        Electric Fence happy when testing.
2505    Version 5.0 13-Sep-04
2506    ---------------------
2508     1. Internal change: literal characters are no longer packed up into items
2509        containing multiple characters in a single byte-string. Each character
2510        is now matched using a separate opcode. However, there may be more than one
2511        byte in the character in UTF-8 mode.
2513     2. The pcre_callout_block structure has two new fields: pattern_position and
2514        next_item_length. These contain the offset in the pattern to the next match
2515        item, and its length, respectively.
2517     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2518        insertion of callouts before each pattern item. Added the /C option to
2519        pcretest to make use of this.
2521     4. On the advice of a Windows user, the lines
2523          #if defined(_WIN32) || defined(WIN32)
2524          _setmode( _fileno( stdout ), 0x8000 );
2525          #endif  /* defined(_WIN32) || defined(WIN32) */
2527        have been added to the source of pcretest. This apparently does useful
2528        magic in relation to line terminators.
2530     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2531        for the benefit of those environments where the "b" makes a difference.
2533     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2534        to know about it. I have put a hack into configure.in that adds in code
2535        to set GCC=yes if CC=icc. This seems to end up at a point in the
2536        generated configure script that is early enough to affect the setting of
2537        compiler options, which is what is needed, but I have no means of testing
2538        whether it really works. (The user who reported this had patched the
2539        generated configure script, which of course I cannot do.)
2541        LATER: After change 22 below (new libtool files), the configure script
2542        seems to know about icc (and also ecc). Therefore, I have commented out
2543        this hack in configure.in.
2545     7. Added support for pkg-config (2 patches were sent in).
2547     8. Negated POSIX character classes that used a combination of internal tables
2548        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2549        [[:^ascii]]. Typically, they would match almost any characters. The other
2550        POSIX classes were not broken in this way.
2552     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2553        to find the match, as PCRE was deluded into thinking that the match had to
2554        start at the start point or following a newline. The same bug applied to
2555        patterns with negative forward assertions or any backward assertions
2556        preceding ".*" at the start, unless the pattern required a fixed first
2557        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2559    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2560        starting at the last subject character, bytes beyond the end of the subject
2561        string were read.
2563    11. Renamed the variable "class" as "classbits" to make life easier for C++
2564        users. (Previously there was a macro definition, but it apparently wasn't
2565        enough.)
2567    12. Added the new field "tables" to the extra data so that tables can be passed
2568        in at exec time, or the internal tables can be re-selected. This allows
2569        a compiled regex to be saved and re-used at a later time by a different
2570        program that might have everything at different addresses.
2572    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2573        -R library as well as a -L library.
2575    14. The debugging options of pcretest (-d on the command line or D on a
2576        pattern) showed incorrect output for anything following an extended class
2577        that contained multibyte characters and which was followed by a quantifier.
2579    15. Added optional support for general category Unicode character properties
2580        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2581        support. It adds about 90K to the size of the library. The meanings of the
2582        inbuilt class escapes such as \d and \s have NOT been changed.
2584    16. Updated pcredemo.c to include calls to free() to release the memory for the
2585        compiled pattern.
2587    17. The generated file chartables.c was being created in the source directory
2588        instead of in the building directory. This caused the build to fail if the
2589        source directory was different from the building directory, and was
2590        read-only.
2592    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2593        file. No doubt somebody will tell me if they don't make sense... Also added
2594        Dan Mooney's comments about building on OpenVMS.
2596    19. Added support for partial matching via the PCRE_PARTIAL option for
2597        pcre_exec() and the \P data escape in pcretest.
2599    20. Extended pcretest with 3 new pattern features:
2601        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2602              write the compiled pattern to the file whose name is "rest-of-line".
2603              This is a straight binary dump of the data, with the saved pointer to
2604              the character tables forced to be NULL. The study data, if any, is
2605              written too. After writing, pcretest reads a new pattern.
2607        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2608              compiled pattern from the given file. There must not be any
2609              occurrences of "<" in the file name (pretty unlikely); if there are,
2610              pcretest will instead treat the initial "<" as a pattern delimiter.
2611              After reading in the pattern, pcretest goes on to read data lines as
2612              usual.
2614        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2615              and 16-bit fields in a compiled pattern, to simulate a pattern that
2616              was compiled on a host of opposite endianness.
2618    21. The pcre-exec() function can now cope with patterns that were compiled on
2619        hosts of opposite endianness, with this restriction:
2621          As for any compiled expression that is saved and used later, the tables
2622          pointer field cannot be preserved; the extra_data field in the arguments
2623          to pcre_exec() should be used to pass in a tables address if a value
2624          other than the default internal tables were used at compile time.
2626    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2627        now diagnosed as an error. Previously, most of the time, a negative number
2628        would have been treated as zero, but if in addition "ovector" was passed as
2629        NULL, a crash could occur.
2631    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2632        new versions from the libtool 1.5 distribution (the last one is a copy of
2633        a file called libtool.m4). This seems to have fixed the need to patch
2634        "configure" to support Darwin 1.3 (which I used to do). However, I still
2635        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2636        workstation).
2638    24. Changed the PCRE licence to be the more standard "BSD" licence.
2641    Version 4.5 01-Dec-03
2642    ---------------------
2644     1. There has been some re-arrangement of the code for the match() function so
2645        that it can be compiled in a version that does not call itself recursively.
2646        Instead, it keeps those local variables that need separate instances for
2647        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2648        needs to "recurse". Keeping track of where control must go is done by means
2649        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2650        hide most of the details from the main code, and operates only if
2651        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2652        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2653        operating.
2655        To make it easier for callers to provide specially tailored get/free
2656        functions for this usage, two new functions, pcre_stack_malloc, and
2657        pcre_stack_free, are used. They are always called in strict stacking order,
2658        and the size of block requested is always the same.
2660        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2661        PCRE has been compiled to use the stack or the heap for recursion. The
2662        -C option of pcretest uses this to show which version is compiled.
2664        A new data escape \S, is added to pcretest; it causes the amounts of store
2665        obtained and freed by both kinds of malloc/free at match time to be added
2666        to the output.
2668     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2669        what's available on my current Linux desktop machine.
2671     3. When matching a UTF-8 string, the test for a valid string at the start has
2672        been extended. If start_offset is not zero, PCRE now checks that it points
2673        to a byte that is the start of a UTF-8 character. If not, it returns
2674        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2675        this is necessary because there may be backward assertions in the pattern.
2676        When matching the same subject several times, it may save resources to use
2677        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2679     4. The code for checking the validity of UTF-8 strings has been tightened so
2680        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2681        containing "overlong sequences".
2683     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2684        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2685        should have been "&", but it just so happened that all the cases this let
2686        through by mistake were picked up later in the function.
2688     6. I had used a variable called "isblank" - this is a C99 function, causing
2689        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2691     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2692        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2693        so the version is shown; (c) stop "make test" echoing "./RunTest".
2695     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2697     9. The prototype for memmove() for systems that don't have it was using
2698        size_t, but the inclusion of the header that defines size_t was later. I've
2699        moved the #includes for the C headers earlier to avoid this.
2701    10. Added some adjustments to the code to make it easier to compiler on certain
2702        special systems:
2704          (a) Some "const" qualifiers were missing.
2705          (b) Added the macro EXPORT before all exported functions; by default this
2706              is defined to be empty.
2707          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2708              that it reads its output file name as an argument instead of writing
2709              to the standard output and assuming this can be redirected.
2711    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2712        class containing characters with values greater than 255, PCRE compilation
2713        went into a loop.
2715    12. A recursive reference to a subpattern that was within another subpattern
2716        that had a minimum quantifier of zero caused PCRE to crash. For example,
2717        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2718        recursion. If the recursively-called subpattern itself had a zero repeat,
2719        that was OK.
2721    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2722        buffer into which it was copied (for escape processing) was still set at
2723        1024, so long lines caused crashes.
2725    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2726        "internal error: code overflow...". This applied to any character class
2727        that was followed by a possessive quantifier.
2729    15. Modified the Makefile to add libpcre.la as a prerequisite for
2730        libpcreposix.la because I was told this is needed for a parallel build to
2731        work.
2733    16. If a pattern that contained .* following optional items at the start was
2734        studied, the wrong optimizing data was generated, leading to matching
2735        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2736        matching string must start with a or b or c. The correct conclusion for
2737        this pattern is that a match can start with any character.
2740    Version 4.4 13-Aug-03
2741    ---------------------
2743     1. In UTF-8 mode, a character class containing characters with values between
2744        127 and 255 was not handled correctly if the compiled pattern was studied.
2745        In fixing this, I have also improved the studying algorithm for such
2746        classes (slightly).
2748     2. Three internal functions had redundant arguments passed to them. Removal
2749        might give a very teeny performance improvement.
2751     3. Documentation bug: the value of the capture_top field in a callout is *one
2752        more than* the number of the hightest numbered captured substring.
2754     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2755        in incorrectly linking with a previously installed version. They now link
2756        explicitly with libpcre.la.
2758     5. configure.in no longer needs to recognize Cygwin specially.
2760     6. A problem in pcre.in for Windows platforms is fixed.
2762     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2763        pcretest, it used to include the size of the study block as part of its
2764        output. Unfortunately, the structure contains a field that has a different
2765        size on different hardware architectures. This meant that the tests that
2766        showed this size failed. As the block is currently always of a fixed size,
2767        this information isn't actually particularly useful in pcretest output, so
2768        I have just removed it.
2770     8. Three pre-processor statements accidentally did not start in column 1.
2771        Sadly, there are *still* compilers around that complain, even though
2772        standard C has not required this for well over a decade. Sigh.
2774     9. In pcretest, the code for checking callouts passed small integers in the
2775        callout_data field, which is a void * field. However, some picky compilers
2776        complained about the casts involved for this on 64-bit systems. Now
2777        pcretest passes the address of the small integer instead, which should get
2778        rid of the warnings.
2780    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2781        both compile and run time, and gives an error if an invalid UTF-8 sequence
2782        is found. There is a option for disabling this check in cases where the
2783        string is known to be correct and/or the maximum performance is wanted.
2785    11. In response to a bug report, I changed one line in Makefile.in from
2787            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2788        to
2789            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2791        to look similar to other lines, but I have no way of telling whether this
2792        is the right thing to do, as I do not use Windows. No doubt I'll get told
2793        if it's wrong...
2796    Version 4.3 21-May-03
2797    ---------------------
2799    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2800       Makefile.
2802    2. Some refactoring to improve the quality of the code:
2804       (i)   The utf8_table... variables are now declared "const".
2806       (ii)  The code for \cx, which used the "case flipping" table to upper case
2807             lower case letters, now just substracts 32. This is ASCII-specific,
2808             but the whole concept of \cx is ASCII-specific, so it seems
2809             reasonable.
2811       (iii) PCRE was using its character types table to recognize decimal and
2812             hexadecimal digits in the pattern. This is silly, because it handles
2813             only 0-9, a-f, and A-F, but the character types table is locale-
2814             specific, which means strange things might happen. A private
2815             table is now used for this - though it costs 256 bytes, a table is
2816             much faster than multiple explicit tests. Of course, the standard
2817             character types table is still used for matching digits in subject
2818             strings against \d.
2820       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2821             ending in _t are). So I've renamed it as ESC_tee.
2823    3. The first argument for regexec() in the POSIX wrapper should have been
2824       defined as "const".
2826    4. Changed pcretest to use malloc() for its buffers so that they can be
2827       Electric Fenced for debugging.
2829    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2830       to read one or more bytes before the start of the subject string. Often this
2831       had no effect on PCRE's behaviour, but in some circumstances it could
2832       provoke a segmentation fault.
2834    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2835       to try to read one or more bytes before the start of the subject string.
2837    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2838       UTF-8 support could misbehave in various ways if the subject string
2839       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2840       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2841       back over UTF-8 characters.)
2844    Version 4.2 14-Apr-03
2845    ---------------------
2847    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2849    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2850         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2851         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2852         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2853         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2854           and BUILD_EXEEXT
2855         Note: automatic setting of the BUILD variables is not yet working
2856         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2857           compile-time but not at link-time
2858         [LINK]: use for linking executables only
2859         make different versions for Windows and non-Windows
2860         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2861           libraries
2862         [LINK_FOR_BUILD]: new variable
2863         [OBJEXT]: use throughout
2864         [EXEEXT]: use throughout
2865         <winshared>: new target
2866         <wininstall>: new target
2867         <dftables.o>: use native compiler
2868         <dftables>: use native linker
2869         <install>: handle Windows platform correctly
2870         <clean>: ditto
2871         <check>: ditto
2872         copy DLL to top builddir before testing
2874       As part of these changes, -no-undefined was removed again. This was reported
2875       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2876       in any case.
2878    3. Some tidies to get rid of compiler warnings:
2880       . In the match_data structure, match_limit was an unsigned long int, whereas
2881         match_call_count was an int. I've made them both unsigned long ints.
2883       . In pcretest the fact that a const uschar * doesn't automatically cast to
2884         a void * provoked a warning.
2886       . Turning on some more compiler warnings threw up some "shadow" variables
2887         and a few more missing casts.
2889    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2890       option, a class that contained a single character with a value between 128
2891       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2893    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2894       option, a class that contained several characters, but with at least one
2895       whose value was between 128 and 255 caused PCRE to crash.
2898    Version 4.1 12-Mar-03
2899    ---------------------
2901    1. Compiling with gcc -pedantic found a couple of places where casts were
2902    needed, and a string in dftables.c that was longer than standard compilers are
2903    required to support.
2905    2. Compiling with Sun's compiler found a few more places where the code could
2906    be tidied up in order to avoid warnings.
2908    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2909    first of these names is deprecated in the latest Autoconf in favour of the name
2910    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2911    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2912    analogy I have changed it to CFLAGS_FOR_BUILD.
2914    4. Added -no-undefined to the linking command in the Makefile, because this is
2915    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2916    linking step for the pcreposix library.
2918    5. PCRE was failing to diagnose the case of two named groups with the same
2919    name.
2921    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2922    literal character that is needed in the subject for a match, and scans along to
2923    ensure that it is present before embarking on the full matching process. This
2924    saves time in cases of nested unlimited repeats that are never going to match.
2925    Problem: the scan can take a lot of time if the subject is very long (e.g.
2926    megabytes), thus penalizing straightforward matches. It is now done only if the
2927    amount of subject to be scanned is less than 1000 bytes.
2929    7. A lesser problem with the same optimization is that it was recording the
2930    first character of an anchored pattern as "needed", thus provoking a search
2931    right along the subject, even when the first match of the pattern was going to
2932    fail. The "needed" character is now not set for anchored patterns, unless it
2933    follows something in the pattern that is of non-fixed length. Thus, it still
2934    fulfils its original purpose of finding quick non-matches in cases of nested
2935    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2938    Version 4.0 17-Feb-03
2939    ---------------------
2941    1. If a comment in an extended regex that started immediately after a meta-item
2942    extended to the end of string, PCRE compiled incorrect data. This could lead to
2943    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2945    2. Moved to autoconf 2.53 and libtool 1.4.2.
2947    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2948    the special perltest8 script is no longer needed - all the tests can be run
2949    from a single perltest script.
2951    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2952    by \s. It has now been removed in PCRE. This means it isn't recognized as
2953    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2954    class [:space:] *does* include VT, thereby creating a mess.
2956    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2957    space and tab.
2959    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2960    its new features into the main test script, reducing the number of scripts.
2962    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2963    were backward compatible, and made the (?i) apply to the whole pattern, as if
2964    /i were given. Now it behaves more logically, and applies the option setting
2965    only to what follows. PCRE has been changed to follow suit. However, if it
2966    finds options settings right at the start of the pattern, it extracts them into
2967    the global options, as before. Thus, they show up in the info data.
2969    8. Added support for the \Q...\E escape sequence. Characters in between are
2970    treated as literals. This is slightly different from Perl in that $ and @ are
2971    also handled as literals inside the quotes. In Perl, they will cause variable
2972    interpolation. Note the following examples:
2974        Pattern            PCRE matches      Perl matches
2976        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2977        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2978        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2980    For compatibility with Perl, \Q...\E sequences are recognized inside character
2981    classes as well as outside them.
2983    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2984    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2985    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2986    signed/unsigned warnings.
2988    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2989    option for pcretest, so I've replaced it by a simple function that does just
2990    that job.
2992    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2993    "pcregrep -".
2995    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2996    Java package. This provides some syntactic sugar for simple cases of what my
2997    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2998    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2999    item, you can use this simplified notation. Note that only makes sense with
3000    greedy quantifiers. Consequently, the use of the possessive quantifier forces
3001    greediness, whatever the setting of the PCRE_UNGREEDY option.
3003    13. A change of greediness default within a pattern was not taking effect at
3004    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
3005    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
3006    was abstracted outside.
3008    14. PCRE now supports the \G assertion. It is true when the current matching
3009    position is at the start point of the match. This differs from \A when the
3010    starting offset is non-zero. Used with the /g option of pcretest (or similar
3011    code), it works in the same way as it does for Perl's /g option. If all
3012    alternatives of a regex begin with \G, the expression is anchored to the start
3013    match position, and the "anchored" flag is set in the compiled expression.
3015    15. Some bugs concerning the handling of certain option changes within patterns
3016    have been fixed. These applied to options other than (?ims). For example,
3017    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
3018    been the other way round. Some of this was related to change 7 above.
3020    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
3021    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
3022    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
3023    POSIX classes only within a class (e.g. /[[:alpha:]]/).
3025    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
3026    mode. Unlike ".", it always matches newline, whatever the setting of
3027    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
3028    assertions. Perl allows it, but it doesn't (in general) work because it can't
3029    calculate the length of the lookbehind. At least, that's the case for Perl
3030    5.8.0 - I've been told they are going to document that it doesn't work in
3031    future.
3033    18. Added an error diagnosis for escapes that PCRE does not support: these are
3034    \L, \l, \N, \P, \p, \U, \u, and \X.
3036    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
3037    reading past the end of the pattern in cases such as /[abcd/.
3039    20. PCRE was getting more memory than necessary for patterns with classes that
3040    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
3042    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
3043    compiling PCRE for use with Virtual Pascal.
3045    22. Small fix to the Makefile to make it work properly if the build is done
3046    outside the source tree.
3048    23. Added a new extension: a condition to go with recursion. If a conditional
3049    subpattern starts with (?(R) the "true" branch is used if recursion has
3050    happened, whereas the "false" branch is used only at the top level.
3052    24. When there was a very long string of literal characters (over 255 bytes
3053    without UTF support, over 250 bytes with UTF support), the computation of how
3054    much memory was required could be incorrect, leading to segfaults or other
3055    strange effects.
3057    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
3058    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
3059    there was a subsequent back reference to those brackets. This meant that, for
3060    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
3061    possible to check for precisely this case. All we can do is abandon the
3062    optimization if .* occurs inside capturing brackets when there are any back
3063    references whatsoever. (See below for a better fix that came later.)
3065    26. The handling of the optimization for finding the first character of a
3066    non-anchored pattern, and for finding a character that is required later in the
3067    match were failing in some cases. This didn't break the matching; it just
3068    failed to optimize when it could. The way this is done has been re-implemented.
3070    27. Fixed typo in error message for invalid (?R item (it said "(?p").
3072    28. Added a new feature that provides some of the functionality that Perl
3073    provides with (?{...}). The facility is termed a "callout". The way it is done
3074    in PCRE is for the caller to provide an optional function, by setting
3075    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
3076    global variable. By default it is unset, which disables all calling out. To get
3077    the function called, the regex must include (?C) at appropriate points. This
3078    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
3079    This provides a means of identifying different callout points. When PCRE
3080    reaches such a point in the regex, if pcre_callout has been set, the external
3081    function is called. It is provided with data in a structure called
3082    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
3083    matching continues; if it returns a non-zero value, the match at the current
3084    point fails. However, backtracking will occur if possible. [This was changed
3085    later and other features added - see item 49 below.]
3087    29. pcretest is upgraded to test the callout functionality. It provides a
3088    callout function that displays information. By default, it shows the start of
3089    the match and the current position in the text. There are some new data escapes
3090    to vary what happens:
3092        \C+         in addition, show current contents of captured substrings
3093        \C-         do not supply a callout function
3094        \C!n        return 1 when callout number n is reached
3095        \C!n!m      return 1 when callout number n is reached for the mth time
3097    30. If pcregrep was called with the -l option and just a single file name, it
3098    output "<stdin>" if a match was found, instead of the file name.
3100    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
3101    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
3102    pcre_exec(). This saves a malloc/free per call. The default value of
3103    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
3104    when configuring.
3106    32. The default maximum size of a compiled pattern is 64K. There have been a
3107    few cases of people hitting this limit. The code now uses macros to handle the
3108    storing of links as offsets within the compiled pattern. It defaults to 2-byte
3109    links, but this can be changed to 3 or 4 bytes by --with-link-size when
3110    configuring. Tests 2 and 5 work only with 2-byte links because they output
3111    debugging information about compiled patterns.
3113    33. Internal code re-arrangements:
3115    (a) Moved the debugging function for printing out a compiled regex into
3116        its own source file (printint.c) and used #include to pull it into
3117        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
3118        separate copies.
3120    (b) Defined the list of op-code names for debugging as a macro in
3121        internal.h so that it is next to the definition of the opcodes.
3123    (c) Defined a table of op-code lengths for simpler skipping along compiled
3124        code. This is again a macro in internal.h so that it is next to the
3125        definition of the opcodes.
3127    34. Added support for recursive calls to individual subpatterns, along the
3128    lines of Robin Houston's patch (but implemented somewhat differently).
3130    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
3131    allow it to read and process whole directories in Win32. This code was
3132    contributed by Lionel Fourquaux; it has not been tested by me.
3134    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
3135    used to name a group. Names consist of alphanumerics and underscores, and must
3136    be unique. Back references use the syntax (?P=name) and recursive calls use
3137    (?P>name) which is a PCRE extension to the Python extension. Groups still have
3138    numbers. The function pcre_fullinfo() can be used after compilation to extract
3139    a name/number map. There are three relevant calls:
3141      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
3142      PCRE_INFO_NAMECOUNT            yields the number of entries
3143      PCRE_INFO_NAMETABLE            yields a pointer to the map.
3145    The map is a vector of fixed-size entries. The size of each entry depends on
3146    the length of the longest name used. The first two bytes of each entry are the
3147    group number, most significant byte first. There follows the corresponding
3148    name, zero terminated. The names are in alphabetical order.
3150    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
3151    case instead of 255. Making it the same both with and without UTF-8 support
3152    means that the same test output works with both.
3154    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
3155    calling malloc() with a zero argument.
3157    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
3158    optimization. I've improved things by keeping a bitmap of backreferences with
3159    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
3160    fact referenced, the optimization can be applied. It is unlikely that a
3161    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
3162    the match to follow \n) will appear inside brackets with a number greater than
3163    31, but if it does, any back reference > 31 suppresses the optimization.
3165    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
3166    of disabling numbered capturing parentheses. Any opening parenthesis that is
3167    not followed by ? behaves as if it were followed by ?: but named parentheses
3168    can still be used for capturing (and they will acquire numbers in the usual
3169    way).
3171    41. Redesigned the return codes from the match() function into yes/no/error so
3172    that errors can be passed back from deep inside the nested calls. A malloc
3173    failure while inside a recursive subpattern call now causes the
3174    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
3176    42. It is now possible to set a limit on the number of times the match()
3177    function is called in a call to pcre_exec(). This facility makes it possible to
3178    limit the amount of recursion and backtracking, though not in a directly
3179    obvious way, because the match() function is used in a number of different
3180    circumstances. The count starts from zero for each position in the subject
3181    string (for non-anchored patterns). The default limit is, for compatibility, a
3182    large number, namely 10 000 000. You can change this in two ways:
3184    (a) When configuring PCRE before making, you can use --with-match-limit=n
3185        to set a default value for the compiled library.
3187    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
3188        a different value is set. See 45 below.
3190    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
3192    43. Added a new function pcre_config(int, void *) to enable run-time extraction
3193    of things that can be changed at compile time. The first argument specifies
3194    what is wanted and the second points to where the information is to be placed.
3195    The current list of available information is:
3197      PCRE_CONFIG_UTF8
3199    The output is an integer that is set to one if UTF-8 support is available;
3200    otherwise it is set to zero.
3204    The output is an integer that it set to the value of the code that is used for
3205    newline. It is either LF (10) or CR (13).
3209    The output is an integer that contains the number of bytes used for internal
3210    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
3214    The output is an integer that contains the threshold above which the POSIX
3215    interface uses malloc() for output vectors. See item 31 above.
3219    The output is an unsigned integer that contains the default limit of the number
3220    of match() calls in a pcre_exec() execution. See 42 above.
3222    44. pcretest has been upgraded by the addition of the -C option. This causes it
3223    to extract all the available output from the new pcre_config() function, and to
3224    output it. The program then exits immediately.
3226    45. A need has arisen to pass over additional data with calls to pcre_exec() in
3227    order to support additional features. One way would have been to define
3228    pcre_exec2() (for example) with extra arguments, but this would not have been
3229    extensible, and would also have required all calls to the original function to
3230    be mapped to the new one. Instead, I have chosen to extend the mechanism that
3231    is used for passing in "extra" data from pcre_study().
3233    The pcre_extra structure is now exposed and defined in pcre.h. It currently
3234    contains the following fields:
3236      flags         a bitmap indicating which of the following fields are set
3237      study_data    opaque data from pcre_study()
3238      match_limit   a way of specifying a limit on match() calls for a specific
3239                      call to pcre_exec()
3240      callout_data  data for callouts (see 49 below)
3242    The flag bits are also defined in pcre.h, and are
3248    The pcre_study() function now returns one of these new pcre_extra blocks, with
3249    the actual study data pointed to by the study_data field, and the
3250    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
3251    before. That is, this change is entirely upwards-compatible and requires no
3252    change to existing code.
3254    If you want to pass in additional data to pcre_exec(), you can either place it
3255    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3256    block.
3258    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3259    data string contains the escape sequence \M, pcretest calls pcre_exec() several
3260    times with different match limits, until it finds the minimum value needed for
3261    pcre_exec() to complete. The value is then output. This can be instructive; for
3262    most simple matches the number is quite small, but for pathological cases it
3263    gets very large very quickly.
3265    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3266    returns the size of the data block pointed to by the study_data field in a
3267    pcre_extra block, that is, the value that was passed as the argument to
3268    pcre_malloc() when PCRE was getting memory in which to place the information
3269    created by pcre_study(). The fourth argument should point to a size_t variable.
3270    pcretest has been extended so that this information is shown after a successful
3271    pcre_study() call when information about the compiled regex is being displayed.
3273    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3274    because what follows is always an absolute path. (Later: it turns out that this
3275    is more than cosmetic for MinGW, because it doesn't like empty path
3276    components.)
3278    49. Some changes have been made to the callout feature (see 28 above):
3280    (i)  A callout function now has three choices for what it returns:
3282           0  =>  success, carry on matching
3283         > 0  =>  failure at this point, but backtrack if possible
3284         < 0  =>  serious error, return this value from pcre_exec()
3286         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3287         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3288         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3289         use by callout functions. It will never be used by PCRE itself.
3291    (ii) The pcre_extra structure (see 45 above) has a void * field called
3292         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3293         pcre_callout_block structure has a field of the same name. The contents of
3294         the field passed in the pcre_extra structure are passed to the callout
3295         function in the corresponding field in the callout block. This makes it
3296         easier to use the same callout-containing regex from multiple threads. For
3297         testing, the pcretest program has a new data escape
3299           \C*n        pass the number n (may be negative) as callout_data
3301         If the callout function in pcretest receives a non-zero value as
3302         callout_data, it returns that value.
3304    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3305    there were some redundant $(CFLAGS) in commands that are now specified as
3306    $(LINK), which already includes $(CFLAGS).
3308    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3309    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3310    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3311    one-byte characters throughout. Note that case-insensitive matching applies
3312    only to characters whose values are less than 256. PCRE doesn't support the
3313    notion of cases for higher-valued characters.
3315    (i)   A character class whose characters are all within 0-255 is handled as
3316          a bit map, and the map is inverted for negative classes. Previously, a
3317          character > 255 always failed to match such a class; however it should
3318          match if the class was a negative one (e.g. [^ab]). This has been fixed.
3320    (ii)  A negated character class with a single character < 255 is coded as
3321          "not this character" (OP_NOT). This wasn't working properly when the test
3322          character was multibyte, either singly or repeated.
3324    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3325          mode, for example: \x{100}{2,3}.
3327    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3328          singly or repeated) now correctly test multibyte characters. However,
3329          PCRE doesn't recognize any characters with values greater than 255 as
3330          digits, spaces, or word characters. Such characters always match \D, \S,
3331          and \W, and never match \d, \s, or \w.
3333    (v)   Classes may now contain characters and character ranges with values
3334          greater than 255. For example: [ab\x{100}-\x{400}].
3336    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
3337          PCRE in UTF-8 mode.
3339    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3340    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3341    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3342    value.)
3344    53. The single man page has become too large. I have therefore split it up into
3345    a number of separate man pages. These also give rise to individual HTML pages;
3346    these are now put in a separate directory, and there is an index.html page that
3347    lists them all. Some hyperlinking between the pages has been installed.
3349    54. Added convenience functions for handling named capturing parentheses.
3351    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3352    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3353    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3354    are faulted.
3356    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3357    calling configure. These values are used when compiling the dftables.c program
3358    which is run to generate the source of the default character tables. They
3359    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3360    you will need to set these values.
3362    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3365    Version 3.9 02-Jan-02
3366    ---------------------
3368    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3370    2. If --disable-static was given, the building process failed when trying to
3371    build pcretest and pcregrep. (For some reason it was using libtool to compile
3372    them, which is not right, as they aren't part of the library.)
3375    Version 3.8 18-Dec-01
3376    ---------------------
3378    1. The experimental UTF-8 code was completely screwed up. It was packing the
3379    bytes in the wrong order. How dumb can you get?
3382    Version 3.7 29-Oct-01
3383    ---------------------
3385    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3386    This caused pcretest, when used on the test data, to segfault. Unfortunately,
3387    this didn't happen under Solaris 8, where I normally test things.
3389    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3390    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3391    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3392    this fix an hour or so after the initial 3.7 release.)
3395    Version 3.6 23-Oct-01
3396    ---------------------
3398    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3399    offsets passed as NULL with zero offset count.
3401    2. The config.guess and config.sub files had not been updated when I moved to
3402    the latest autoconf.
3405    Version 3.5 15-Aug-01
3406    ---------------------
3408    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3409    had been forgotten.
3411    2. By using declared but undefined structures, we can avoid using "void"
3412    definitions in pcre.h while keeping the internal definitions of the structures
3413    private.
3415    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3416    user point of view, this means that both static and shared libraries are built
3417    by default, but this can be individually controlled. More of the work of
3418    handling this static/shared cases is now inside libtool instead of PCRE's make
3419    file.
3421    4. The pcretest utility is now installed along with pcregrep because it is
3422    useful for users (to test regexs) and by doing this, it automatically gets
3423    relinked by libtool. The documentation has been turned into a man page, so
3424    there are now .1, .txt, and .html versions in /doc.
3426    5. Upgrades to pcregrep:
3427       (i)   Added long-form option names like gnu grep.
3428       (ii)  Added --help to list all options with an explanatory phrase.
3429       (iii) Added -r, --recursive to recurse into sub-directories.
3430       (iv)  Added -f, --file to read patterns from a file.
3432    6. pcre_exec() was referring to its "code" argument before testing that
3433    argument for NULL (and giving an error if it was NULL).
3435    7. Upgraded Makefile.in to allow for compiling in a different directory from
3436    the source directory.
3438    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3439    options bits, the pointer it was passed was to an int instead of to an unsigned
3440    long int. This mattered only on 64-bit systems.
3442    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3443    generated) instead of pcre.in, which it its source. Also made the same change
3444    in several of the .c files.
3446    10. A new release of gcc defines printf() as a macro, which broke pcretest
3447    because it had an ifdef in the middle of a string argument for printf(). Fixed
3448    by using separate calls to printf().
3450    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3451    script, to force use of CR or LF instead of \n in the source. On non-Unix
3452    systems, the value can be set in config.h.
3454    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3455    absolute limit. Changed the text of the error message to make this clear, and
3456    likewise updated the man page.
3458    13. The limit of 99 on the number of capturing subpatterns has been removed.
3459    The new limit is 65535, which I hope will not be a "real" limit.
3462    Version 3.4 22-Aug-00
3463    ---------------------
3465    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3467    2. Diagnose condition (?(0) as an error instead of crashing on matching.
3470    Version 3.3 01-Aug-00
3471    ---------------------
3473    1. If an octal character was given, but the value was greater than \377, it
3474    was not getting masked to the least significant bits, as documented. This could
3475    lead to crashes in some systems.
3477    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3478    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3480    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3481    These just pass their arguments on to (pcre_free)(), but they are provided
3482    because some uses of PCRE bind it to non-C systems that can call its functions,
3483    but cannot call free() or pcre_free() directly.
3485    4. Add "make test" as a synonym for "make check". Corrected some comments in
3486    the Makefile.
3488    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3489    Makefile.
3491    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3492    command called pgrep for grepping around the active processes.
3494    7. Added the beginnings of support for UTF-8 character strings.
3496    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3497    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3498    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3499    out for the ar command.)
3502    Version 3.2 12-May-00
3503    ---------------------
3505    This is purely a bug fixing release.
3507    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3508    of ZA. This was just one example of several cases that could provoke this bug,
3509    which was introduced by change 9 of version 2.00. The code for breaking
3510    infinite loops after an iteration that matches an empty string was't working
3511    correctly.
3513    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3514    when matched against abbab (for example). After matching an empty string, it
3515    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3516    caused it to match further down the string than it should.
3518    3. The code contained an inclusion of sys/types.h. It isn't clear why this
3519    was there because it doesn't seem to be needed, and it causes trouble on some
3520    systems, as it is not a Standard C header. It has been removed.
3522    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3523    were reported on the Macintosh. The changes were from
3525      while ((c = *(++ptr)) != 0 && c != '\n');
3526    to
3527      while ((c = *(++ptr)) != 0 && c != '\n') ;
3529    Totally extraordinary, but if that's what it takes...
3531    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3532    available. Added HAVE_BCOPY and an autoconf test for it; if neither
3533    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3534    assumes the way PCRE uses memmove() (always moving upwards).
3536    6. PCRE is being used in one environment where strchr() is not available. There
3537    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3538    faster code anyway.
3541  Version 3.1 09-Feb-00  Version 3.1 09-Feb-00
3542  ---------------------  ---------------------

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