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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.3 05-Jul-07  Version 8.13 30-Apr-2011
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
9    2.  Two minor typos in pcre_internal.h have been fixed.
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collection of tests with study enabled,
83        and thereby test pcre_study() more easily.
86    Version 8.12 15-Jan-2011
87    ------------------------
89    1.  Fixed some typos in the markup of the man pages, and wrote a script that
90        checks for such things as part of the documentation building process.
92    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
93        --match-limit and --recursion-limit options (added for 8.11). In
94        particular, this made one of the standard tests fail. (The integer value
95        went into the wrong half of a long int.)
97    3.  If the --colour option was given to pcregrep with -v (invert match), it
98        did strange things, either producing crazy output, or crashing. It should,
99        of course, ignore a request for colour when reporting lines that do not
100        match.
102    4.  Another pcregrep bug caused similar problems if --colour was specified with
103        -M (multiline) and the pattern match finished with a line ending.
105    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
106        matched in multiline mode, the following line was shown as part of the
107        match. This seems wrong, so I have changed it.
109    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
110        the check for further matches in the same line (so they could be coloured)
111        to overrun the end of the current line. If another match was found, it was
112        incorrectly shown (and then shown again when found in the next line).
114    7.  If pcregrep was compiled under Windows, there was a reference to the
115        function pcregrep_exit() before it was defined. I am assuming this was
116        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
117        reported by a user. I've moved the definition above the reference.
120    Version 8.11 10-Dec-2010
121    ------------------------
123    1.  (*THEN) was not working properly if there were untried alternatives prior
124        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
125        backtracked to try for "b" instead of moving to the next alternative branch
126        at the same level (in this case, to look for "c"). The Perl documentation
127        is clear that when (*THEN) is backtracked onto, it goes to the "next
128        alternative in the innermost enclosing group".
130    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
131        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
132        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
133        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
134        (*THEN).
136    3.  If \s appeared in a character class, it removed the VT character from
137        the class, even if it had been included by some previous item, for example
138        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
139        of \s, but is part of the POSIX "space" class.)
141    4.  A partial match never returns an empty string (because you can always
142        match an empty string at the end of the subject); however the checking for
143        an empty string was starting at the "start of match" point. This has been
144        changed to the "earliest inspected character" point, because the returned
145        data for a partial match starts at this character. This means that, for
146        example, /(?<=abc)def/ gives a partial match for the subject "abc"
147        (previously it gave "no match").
149    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
150        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
151        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
152        has an implication that the given string is incomplete (because a partial
153        match is preferred over a full match). For this reason, these items now
154        give a partial match in this situation. [Aside: previously, the one case
155        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
156        match rather than a full match, which was wrong by the old rules, but is
157        now correct.]
159    6.  There was a bug in the handling of #-introduced comments, recognized when
160        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
161        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
162        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
163        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
164        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
165        places in pcre_compile().
167    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
168        comments when looking ahead for named forward references to subpatterns,
169        the only newline sequence it recognized was NL. It now handles newlines
170        according to the set newline convention.
172    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
173        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
174        cater for a lack of strerror(). These oversights have been fixed.
176    9.  Added --match-limit and --recursion-limit to pcregrep.
178    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
180    11. When the -o option was used, pcregrep was setting a return code of 1, even
181        when matches were found, and --line-buffered was not being honoured.
183    12. Added an optional parentheses number to the -o and --only-matching options
184        of pcregrep.
186    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
187        can match an empty string. The code to do it in pcretest and pcredemo
188        needed fixing:
190        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
191            only one byte after an empty string match just before CRLF (this case
192            just got forgotten; "any" and "anycrlf" were OK).
194        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
195            mode when an empty string match preceded an ASCII character followed by
196            a non-ASCII character. (The code for advancing by one character rather
197            than one byte was nonsense.)
199        (c) The pcredemo.c sample program did not have any code at all to handle
200            the cases when CRLF is a valid newline sequence.
202    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
203        as a starting offset was within the subject string. There is now a new
204        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
205        negative or greater than the length of the string. In order to test this,
206        pcretest is extended to allow the setting of negative starting offsets.
208    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
209        starting offset points to the beginning of a UTF-8 character was
210        unnecessarily clumsy. I tidied it up.
212    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
213        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
215    17. Nobody had reported that the --include_dir option, which was added in
216        release 7.7 should have been called --include-dir (hyphen, not underscore)
217        for compatibility with GNU grep. I have changed it to --include-dir, but
218        left --include_dir as an undocumented synonym, and the same for
219        --exclude-dir, though that is not available in GNU grep, at least as of
220        release 2.5.4.
222    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
223        characters from a string of bytes) have been redefined so as not to use
224        loops, in order to improve performance in some environments. At the same
225        time, I abstracted some of the common code into auxiliary macros to save
226        repetition (this should not affect the compiled code).
228    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
229        compile-time error is now given if \c is not followed by an ASCII
230        character, that is, a byte less than 128. (In EBCDIC mode, the code is
231        different, and any byte value is allowed.)
233    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
234        START_OPTIMIZE option, which is now allowed at compile time - but just
235        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
236        to pcregrep and other applications that have no direct access to PCRE
237        options. The new /Y option in pcretest sets this option when calling
238        pcre_compile().
240    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
241        back references. Groups containing recursive back references were forced to
242        be atomic by that change, but in the case of named groups, the amount of
243        memory required was incorrectly computed, leading to "Failed: internal
244        error: code overflow". This has been fixed.
246    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
247        pcretest.c, to avoid build problems in some Borland environments.
250    Version 8.10 25-Jun-2010
251    ------------------------
253    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
254        THEN.
256    2.  (*ACCEPT) was not working when inside an atomic group.
258    3.  Inside a character class, \B is treated as a literal by default, but
259        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
260        causes the error). The code is unchanged, but I tidied the documentation.
262    4.  Inside a character class, PCRE always treated \R and \X as literals,
263        whereas Perl faults them if its -w option is set. I have changed PCRE so
264        that it faults them when PCRE_EXTRA is set.
266    5.  Added support for \N, which always matches any character other than
267        newline. (It is the same as "." when PCRE_DOTALL is not set.)
269    6.  When compiling pcregrep with newer versions of gcc which may have
270        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
271        declared with attribute warn_unused_result" were given. Just casting the
272        result to (void) does not stop the warnings; a more elaborate fudge is
273        needed. I've used a macro to implement this.
275    7.  Minor change to pcretest.c to avoid a compiler warning.
277    8.  Added four artifical Unicode properties to help with an option to make
278        \s etc use properties (see next item). The new properties are: Xan
279        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
281    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
282        use Unicode properties. (*UCP) at the start of a pattern can be used to set
283        this option. Modified pcretest to add /W to test this facility. Added
284        REG_UCP to make it available via the POSIX interface.
286    10. Added --line-buffered to pcregrep.
288    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
289        studied, and the match started with a letter with a code point greater than
290        127 whose first byte was different to the first byte of the other case of
291        the letter, the other case of this starting letter was not recognized
292        (#976).
294    12. If a pattern that was studied started with a repeated Unicode property
295        test, for example, \p{Nd}+, there was the theoretical possibility of
296        setting up an incorrect bitmap of starting bytes, but fortunately it could
297        not have actually happened in practice until change 8 above was made (it
298        added property types that matched character-matching opcodes).
300    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
301        possible starting bytes for non-anchored patterns.
303    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
304        \R, and also a number of cases that involve Unicode properties, both
305        explicit and implicit when PCRE_UCP is set.
307    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
308        input, it could crash or give wrong results if characters with values
309        greater than 0xc0 were present in the subject string. (Detail: it assumed
310        UTF-8 input when processing these items.)
312    16. Added a lot of (int) casts to avoid compiler warnings in systems where
313        size_t is 64-bit (#991).
315    17. Added a check for running out of memory when PCRE is compiled with
316        --disable-stack-for-recursion (#990).
318    18. If the last data line in a file for pcretest does not have a newline on
319        the end, a newline was missing in the output.
321    19. The default pcre_chartables.c file recognizes only ASCII characters (values
322        less than 128) in its various bitmaps. However, there is a facility for
323        generating tables according to the current locale when PCRE is compiled. It
324        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
325        characters, are recognized by isspace() and therefore were getting set in
326        these tables, and indeed these tables seem to approximate to ISO 8859. This
327        caused a problem in UTF-8 mode when pcre_study() was used to create a list
328        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
329        which of course cannot start UTF-8 characters. I have changed the code so
330        that only real ASCII characters (less than 128) and the correct starting
331        bytes for UTF-8 encodings are set for characters greater than 127 when in
332        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
333        altogether.)
335    20. Added the /T option to pcretest so as to be able to run tests with non-
336        standard character tables, thus making it possible to include the tests
337        used for 19 above in the standard set of tests.
339    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
340        reference to a subpattern the other side of a comment that contains an
341        opening parenthesis caused either an internal compiling error, or a
342        reference to the wrong subpattern.
345    Version 8.02 19-Mar-2010
346    ------------------------
348    1.  The Unicode data tables have been updated to Unicode 5.2.0.
350    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
351        configured.
353    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
354        original author of that file, following a query about its status.
356    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
357        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
359    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
360        quantifier applied to a forward-referencing subroutine call, could compile
361        incorrect code or give the error "internal error: previously-checked
362        referenced subpattern not found".
364    6.  Both MS Visual Studio and Symbian OS have problems with initializing
365        variables to point to external functions. For these systems, therefore,
366        pcre_malloc etc. are now initialized to local functions that call the
367        relevant global functions.
369    7.  There were two entries missing in the vectors called coptable and poptable
370        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
371        I've fixed the data, and added a kludgy way of testing at compile time that
372        the lengths are correct (equal to the number of opcodes).
374    8.  Following on from 7, I added a similar kludge to check the length of the
375        eint vector in pcreposix.c.
377    9.  Error texts for pcre_compile() are held as one long string to avoid too
378        much relocation at load time. To find a text, the string is searched,
379        counting zeros. There was no check for running off the end of the string,
380        which could happen if a new error number was added without updating the
381        string.
383    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
385    11. \K was not working if it appeared in an atomic group or in a group that
386        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
387        \K is "not well defined" if used in an assertion. PCRE now accepts it if
388        the assertion is positive, but not if it is negative.
390    12. Change 11 fortuitously reduced the size of the stack frame used in the
391        "match()" function of pcre_exec.c by one pointer. Forthcoming
392        implementation of support for (*MARK) will need an extra pointer on the
393        stack; I have reserved it now, so that the stack frame size does not
394        decrease.
396    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
397        item in branch that calls a recursion is a subroutine call - as in the
398        second branch in the above example - was incorrectly given the compile-
399        time error "recursive call could loop indefinitely" because pcre_compile()
400        was not correctly checking the subroutine for matching a non-empty string.
402    14. The checks for overrunning compiling workspace could trigger after an
403        overrun had occurred. This is a "should never occur" error, but it can be
404        triggered by pathological patterns such as hundreds of nested parentheses.
405        The checks now trigger 100 bytes before the end of the workspace.
407    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
410    Version 8.01 19-Jan-2010
411    ------------------------
413    1.  If a pattern contained a conditional subpattern with only one branch (in
414        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
415        computed the wrong minimum data length (which is of course zero for such
416        subpatterns). This could cause incorrect "no match" results.
418    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
419        the pattern is reset in the first branch, pcre_compile() failed with
420        "internal error: code overflow at offset...". This happened only when
421        the reset was to the original external option setting. (An optimization
422        abstracts leading options settings into an external setting, which was the
423        cause of this.)
425    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
426        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
427        assertion pattern did not match (meaning that the assertion was true), it
428        was incorrectly treated as false if the SKIP had been reached during the
429        matching. This also applied to assertions used as conditions.
431    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
432        assertion subpattern, including such a pattern used as a condition,
433        unpredictable results occurred, instead of the error return
436    5.  The C++ GlobalReplace function was not working like Perl for the special
437        situation when an empty string is matched. It now does the fancy magic
438        stuff that is necessary.
440    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
441        removed. (These were left over from very, very early versions of PCRE.)
443    7.  Some cosmetic changes to the code to make life easier when compiling it
444        as part of something else:
446        (a) Change DEBUG to PCRE_DEBUG.
448        (b) In pcre_compile(), rename the member of the "branch_chain" structure
449            called "current" as "current_branch", to prevent a collision with the
450            Linux macro when compiled as a kernel module.
452        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
453            prevent a collision with the Linux macro when compiled as a kernel
454            module.
456    8.  In pcre_compile() there are some checks for integer overflows that used to
457        cast potentially large values to (double). This has been changed to that
458        when building, a check for int64_t is made, and if it is found, it is used
459        instead, thus avoiding the use of floating point arithmetic. (There is no
460        other use of FP in PCRE.) If int64_t is not found, the fallback is to
461        double.
463    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
464        2005 (difference between two addresses compared to an unsigned value).
466    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
467        custom one, because of the following reported problem in Windows:
469          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
470              under Win32.
471          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
472              therefore missing the function definition.
473          - The compiler thus generates a "C" signature for the test function.
474          - The linker fails to find the "C" function.
475          - PCRE fails to configure if asked to do so against libbz2.
477    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
478        messages were output:
480          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
481          rerunning libtoolize, to keep the correct libtool macros in-tree.
482          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
484        I have done both of these things.
486    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
487        most of the time, it *can* run out if it is given a pattern that contains a
488        runaway infinite recursion. I updated the discussion in the pcrestack man
489        page.
491    13. Now that we have gone to the x.xx style of version numbers, the minor
492        version may start with zero. Using 08 or 09 is a bad idea because users
493        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
494        interpreted as invalid octal numbers. I've updated the previous comment in
495        configure.ac, and also added a check that gives an error if 08 or 09 are
496        used.
498    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
499        causing partial matching to fail when the end of the subject matched \W
500        in a UTF-8 pattern where \W was quantified with a minimum of 3.
502    15. There were some discrepancies between the declarations in pcre_internal.h
503        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
504        their definitions. The declarations used "const uschar *" and the
505        definitions used USPTR. Even though USPTR is normally defined as "const
506        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
507        reported that: "This difference in casting confuses some C++ compilers, for
508        example, SunCC recognizes above declarations as different functions and
509        generates broken code for hbpcre." I have changed the declarations to use
510        USPTR.
512    16. GNU libtool is named differently on some systems. The autogen.sh script now
513        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
514        (FreeBSD).
516    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
517        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
518        comment: "Figure out how to create a longlong from a string: strtoll and
519        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
520        instance, but it only takes 2 args instead of 3!"
522    18. A subtle bug concerned with back references has been fixed by a change of
523        specification, with a corresponding code fix. A pattern such as
524        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
525        refers, was giving matches when it shouldn't. For example, xa=xaaa would
526        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
527        same bug. Such groups have to be quantified to be useful, or contained
528        inside another quantified group. (If there's no repetition, the reference
529        can never match.) The problem arises because, having left the group and
530        moved on to the rest of the pattern, a later failure that backtracks into
531        the group uses the captured value from the final iteration of the group
532        rather than the correct earlier one. I have fixed this in PCRE by forcing
533        any group that contains a reference to itself to be an atomic group; that
534        is, there cannot be any backtracking into it once it has completed. This is
535        similar to recursive and subroutine calls.
538    Version 8.00 19-Oct-09
539    ----------------------
541    1.  The table for translating pcre_compile() error codes into POSIX error codes
542        was out-of-date, and there was no check on the pcre_compile() error code
543        being within the table. This could lead to an OK return being given in
544        error.
546    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
547        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
548        in a Windows environment.
550    3.  The pcregrep --count option prints the count for each file even when it is
551        zero, as does GNU grep. However, pcregrep was also printing all files when
552        --files-with-matches was added. Now, when both options are given, it prints
553        counts only for those files that have at least one match. (GNU grep just
554        prints the file name in this circumstance, but including the count seems
555        more useful - otherwise, why use --count?) Also ensured that the
556        combination -clh just lists non-zero counts, with no names.
558    4.  The long form of the pcregrep -F option was incorrectly implemented as
559        --fixed_strings instead of --fixed-strings. This is an incompatible change,
560        but it seems right to fix it, and I didn't think it was worth preserving
561        the old behaviour.
563    5.  The command line items --regex=pattern and --regexp=pattern were not
564        recognized by pcregrep, which required --regex pattern or --regexp pattern
565        (with a space rather than an '='). The man page documented the '=' forms,
566        which are compatible with GNU grep; these now work.
568    6.  No libpcreposix.pc file was created for pkg-config; there was just
569        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
571    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
572        when UCP support is not needed, by modifying the Python script that
573        generates it from Unicode data files. This should not matter if the module
574        is correctly used as a library, but I received one complaint about 50K of
575        unwanted data. My guess is that the person linked everything into his
576        program rather than using a library. Anyway, it does no harm.
578    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
579        was a minimum greater than 1 for a wide character in a possessive
580        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
581        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
582        character. Chaos in the form of incorrect output or a compiling loop could
583        result.
585    9.  The restrictions on what a pattern can contain when partial matching is
586        requested for pcre_exec() have been removed. All patterns can now be
587        partially matched by this function. In addition, if there are at least two
588        slots in the offset vector, the offset of the earliest inspected character
589        for the match and the offset of the end of the subject are set in them when
590        PCRE_ERROR_PARTIAL is returned.
592    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
593        synonymous with PCRE_PARTIAL, for backwards compatibility, and
594        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
595        and may be more useful for multi-segment matching.
597    11. Partial matching with pcre_exec() is now more intuitive. A partial match
598        used to be given if ever the end of the subject was reached; now it is
599        given only if matching could not proceed because another character was
600        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
601        string "Z", which now yields "no match" instead of "partial match". In the
602        case of pcre_dfa_exec(), "no match" is given if every matching path for the
603        final character ended with (*FAIL).
605    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
606        if the pattern had a "must contain" character that was already found in the
607        earlier partial match, unless partial matching was again requested. For
608        example, with the pattern /dog.(body)?/, the "must contain" character is
609        "g". If the first part-match was for the string "dog", restarting with
610        "sbody" failed. This bug has been fixed.
612    13. The string returned by pcre_dfa_exec() after a partial match has been
613        changed so that it starts at the first inspected character rather than the
614        first character of the match. This makes a difference only if the pattern
615        starts with a lookbehind assertion or \b or \B (\K is not supported by
616        pcre_dfa_exec()). It's an incompatible change, but it makes the two
617        matching functions compatible, and I think it's the right thing to do.
619    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
620        so that the demonstration program is easily available in environments where
621        PCRE has not been installed from source.
623    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
624        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
625        library.
627    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
628        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
629        is not the first non-POSIX option to be added. Clearly some people find
630        these options useful.
632    17. If a caller to the POSIX matching function regexec() passes a non-zero
633        value for nmatch with a NULL value for pmatch, the value of
634        nmatch is forced to zero.
636    18. RunGrepTest did not have a test for the availability of the -u option of
637        the diff command, as RunTest does. It now checks in the same way as
638        RunTest, and also checks for the -b option.
640    19. If an odd number of negated classes containing just a single character
641        interposed, within parentheses, between a forward reference to a named
642        subpattern and the definition of the subpattern, compilation crashed with
643        an internal error, complaining that it could not find the referenced
644        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
645        [The bug was that it was starting one character too far in when skipping
646        over the character class, thus treating the ] as data rather than
647        terminating the class. This meant it could skip too much.]
649    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
650        /g option in pcretest when the pattern contains \K, which makes it possible
651        to have an empty string match not at the start, even when the pattern is
652        anchored. Updated pcretest and pcredemo to use this option.
654    21. If the maximum number of capturing subpatterns in a recursion was greater
655        than the maximum at the outer level, the higher number was returned, but
656        with unset values at the outer level. The correct (outer level) value is
657        now given.
659    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
660        PCRE did not set those parentheses (unlike Perl). I have now found a way to
661        make it do so. The string so far is captured, making this feature
662        compatible with Perl.
664    23. The tests have been re-organized, adding tests 11 and 12, to make it
665        possible to check the Perl 5.10 features against Perl 5.10.
667    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
668        pattern matches a fixed length string. PCRE did not allow this; now it
669        does. Neither allows recursion.
671    25. I finally figured out how to implement a request to provide the minimum
672        length of subject string that was needed in order to match a given pattern.
673        (It was back references and recursion that I had previously got hung up
674        on.) This code has now been added to pcre_study(); it finds a lower bound
675        to the length of subject needed. It is not necessarily the greatest lower
676        bound, but using it to avoid searching strings that are too short does give
677        some useful speed-ups. The value is available to calling programs via
678        pcre_fullinfo().
680    26. While implementing 25, I discovered to my embarrassment that pcretest had
681        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
682        study optimizations had never been tested with that matching function.
683        Oops. What is worse, even when it was passed study data, there was a bug in
684        pcre_dfa_exec() that meant it never actually used it. Double oops. There
685        were also very few tests of studied patterns with pcre_dfa_exec().
687    27. If (?| is used to create subpatterns with duplicate numbers, they are now
688        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
689        on the other side of the coin, they are no longer allowed to have different
690        names, because these cannot be distinguished in PCRE, and this has caused
691        confusion. (This is a difference from Perl.)
693    28. When duplicate subpattern names are present (necessarily with different
694        numbers, as required by 27 above), and a test is made by name in a
695        conditional pattern, either for a subpattern having been matched, or for
696        recursion in such a pattern, all the associated numbered subpatterns are
697        tested, and the overall condition is true if the condition is true for any
698        one of them. This is the way Perl works, and is also more like the way
699        testing by number works.
702    Version 7.9 11-Apr-09
703    ---------------------
705    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
706        (pcretest), all targets were linked against these libraries. This included
707        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
708        libraries. This caused unwanted dependencies to be created. This problem
709        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
710        pcretest is linked with readline.
712    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
713        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
714        moved outside it again, because FALSE and TRUE are already defined in AIX,
715        but BOOL is not.
717    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
718        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
720    4.  The pcregrep documentation said spaces were inserted as well as colons (or
721        hyphens) following file names and line numbers when outputting matching
722        lines. This is not true; no spaces are inserted. I have also clarified the
723        wording for the --colour (or --color) option.
725    5.  In pcregrep, when --colour was used with -o, the list of matching strings
726        was not coloured; this is different to GNU grep, so I have changed it to be
727        the same.
729    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
730        each matching line was coloured. Now it goes on to look for further matches
731        of any of the test patterns, which is the same behaviour as GNU grep.
733    7.  A pattern that could match an empty string could cause pcregrep to loop; it
734        doesn't make sense to accept an empty string match in pcregrep, so I have
735        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
736        seems to be how GNU grep behaves.
738    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
739        start or after a newline", because the conditional assertion was not being
740        correctly handled. The rule now is that both the assertion and what follows
741        in the first alternative must satisfy the test.
743    9.  If auto-callout was enabled in a pattern with a conditional group whose
744        condition was an assertion, PCRE could crash during matching, both with
745        pcre_exec() and pcre_dfa_exec().
747    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
748        used for matching.
750    11. Unicode property support in character classes was not working for
751        characters (bytes) greater than 127 when not in UTF-8 mode.
753    12. Added the -M command line option to pcretest.
755    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
757    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
759    16. Added comments and documentation about mis-use of no_arg in the C++
760        wrapper.
762    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
763        from Martin Jerabek that uses macro names for all relevant character and
764        string constants.
766    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
767        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
768        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
769        these, but not everybody uses configure.
771    19. A conditional group that had only one branch was not being correctly
772        recognized as an item that could match an empty string. This meant that an
773        enclosing group might also not be so recognized, causing infinite looping
774        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
775        with the subject "ab", where knowledge that the repeated group can match
776        nothing is needed in order to break the loop.
778    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
779        exec(), but without supplying a callout function, matching went wrong.
781    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
782        leak if the size of the offset vector was greater than 30. When the vector
783        is smaller, the saved offsets during recursion go onto a local stack
784        vector, but for larger vectors malloc() is used. It was failing to free
785        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
786        error, in fact).
788    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
789        heapframe that is used only when UTF-8 support is enabled. This caused no
790        problem, but was untidy.
792    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
793        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
794        included within another project.
796    24. Steven Van Ingelgem's patches to add more options to the CMake support,
797        slightly modified by me:
799          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
800              not building pcregrep.
802          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
803              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
805    25. Forward references, both numeric and by name, in patterns that made use of
806        duplicate group numbers, could behave incorrectly or give incorrect errors,
807        because when scanning forward to find the reference group, PCRE was not
808        taking into account the duplicate group numbers. A pattern such as
809        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
811    26. Changed a few more instances of "const unsigned char *" to USPTR, making
812        the feature of a custom pointer more persuasive (as requested by a user).
814    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
815        pcretest.c, inside #ifndefs, because it seems they are sometimes already
816        pre-defined.
818    28. Added support for (*UTF8) at the start of a pattern.
820    29. Arrange for flags added by the "release type" setting in CMake to be shown
821        in the configuration summary.
824    Version 7.8 05-Sep-08
825    ---------------------
827    1.  Replaced UCP searching code with optimized version as implemented for Ad
828        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
829        stage table and inline lookup instead of a function, giving speed ups of 2
830        to 5 times on some simple patterns that I tested. Permission was given to
831        distribute the MultiStage2.py script that generates the tables (it's not in
832        the tarball, but is in the Subversion repository).
834    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
835        scripts.
837    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
838        a group with a zero qualifier. The result of the study could be incorrect,
839        or the function might crash, depending on the pattern.
841    4.  Caseless matching was not working for non-ASCII characters in back
842        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
843        It now works when Unicode Property Support is available.
845    5.  In pcretest, an escape such as \x{de} in the data was always generating
846        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
847        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
848        truncation.
850    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
852    7.  Added two (int) casts to pcregrep when printing the difference of two
853        pointers, in case they are 64-bit values.
855    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
856        test 2 if it fails.
858    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
859        and a #define of that name to empty if it is not externally set. This is to
860        allow users of MSVC to set it if necessary.
862    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
863        the convenience functions in the pcre_get.c source file.
865    11. An option change at the start of a pattern that had top-level alternatives
866        could cause overwriting and/or a crash. This command provoked a crash in
867        some environments:
869          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
871        This potential security problem was recorded as CVE-2008-2371.
873    12. For a pattern where the match had to start at the beginning or immediately
874        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
875        pcre_dfa_exec() could read past the end of the passed subject if there was
876        no match. To help with detecting such bugs (e.g. with valgrind), I modified
877        pcretest so that it places the subject at the end of its malloc-ed buffer.
879    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
880        exec() might read past the end of the data buffer in UTF-8 mode.
882    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
883        the data contained the byte 0x85 as part of a UTF-8 character within its
884        first line. This applied both to normal and DFA matching.
886    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
887        /^[^d]*?$/8 failed to match "abc".
889    16. Added a missing copyright notice to pcrecpp_internal.h.
891    17. Make it more clear in the documentation that values returned from
892        pcre_exec() in ovector are byte offsets, not character counts.
894    18. Tidied a few places to stop certain compilers from issuing warnings.
896    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
897        supplied by Stefan Weber. I made a further small update for 7.8 because
898        there is a change of source arrangements: the pcre_searchfuncs.c module is
899        replaced by pcre_ucd.c.
902    Version 7.7 07-May-08
903    ---------------------
905    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
906        a string to a long long, pretend we don't even have a long long." This is
907        done by checking for the strtoq, strtoll, and _strtoi64 functions.
909    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
910        pre-7.6 versions, which defined a global no_arg variable instead of putting
911        it in the RE class. (See also #8 below.)
913    3.  Remove a line of dead code, identified by coverity and reported by Nuno
914        Lopes.
916    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
918        (1) The include/exclude patterns were being applied to the whole pathnames
919            of files, instead of just to the final components.
921        (2) If there was more than one level of directory, the subdirectories were
922            skipped unless they satisfied the include/exclude conditions. This is
923            inconsistent with GNU grep (and could even be seen as contrary to the
924            pcregrep specification - which I improved to make it absolutely clear).
925            The action now is always to scan all levels of directory, and just
926            apply the include/exclude patterns to regular files.
928    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
929        --exclude_dir in the tests to avoid scanning .svn directories.
931    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
932        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
933        doesn't support NULs in patterns.
935    7.  Added some missing "const"s to declarations of static tables in
936        pcre_compile.c and pcre_dfa_exec.c.
938    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
939        caused by fix #2  above. (Subsequently also a second patch to fix the
940        first patch. And a third patch - this was a messy problem.)
942    9.  Applied Craig's patch to remove the use of push_back().
944    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
945        matching function regexec().
947    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
948        which, however, unlike Perl's \g{...}, are subroutine calls, not back
949        references. PCRE supports relative numbers with this syntax (I don't think
950        Oniguruma does).
952    12. Previously, a group with a zero repeat such as (...){0} was completely
953        omitted from the compiled regex. However, this means that if the group
954        was called as a subroutine from elsewhere in the pattern, things went wrong
955        (an internal error was given). Such groups are now left in the compiled
956        pattern, with a new opcode that causes them to be skipped at execution
957        time.
959    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
960        to the way PCRE behaves:
962        (a) A lone ] character is dis-allowed (Perl treats it as data).
964        (b) A back reference to an unmatched subpattern matches an empty string
965            (Perl fails the current match path).
967        (c) A data ] in a character class must be notated as \] because if the
968            first data character in a class is ], it defines an empty class. (In
969            Perl it is not possible to have an empty class.) The empty class []
970            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
971            The negative empty class [^] matches any one character, independently
972            of the DOTALL setting.
974    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
975        non-existent subpattern following a character class starting with ']' and
976        containing () gave an internal compiling error instead of "reference to
977        non-existent subpattern". Fortunately, when the pattern did exist, the
978        compiled code was correct. (When scanning forwards to check for the
979        existencd of the subpattern, it was treating the data ']' as terminating
980        the class, so got the count wrong. When actually compiling, the reference
981        was subsequently set up correctly.)
983    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
984        it was being rejected as not supported by pcre_dfa_exec(), even though
985        other assertions are supported. I have made pcre_dfa_exec() support
986        (*FAIL).
988    16. The implementation of 13c above involved the invention of a new opcode,
989        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
990        cannot be changed at match time, I realized I could make a small
991        improvement to matching performance by compiling OP_ALLANY instead of
992        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
993        on the OP_ANY path.
995    17. Compiling pcretest on Windows with readline support failed without the
996        following two fixes: (1) Make the unistd.h include conditional on
997        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
999    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
1000        ncurses library to be included for pcretest when ReadLine support is
1001        requested, but also to allow for it to be overridden. This patch came from
1002        Daniel Bergström.
1004    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
1005        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
1006        any errors with the current Unicode tables. Thanks to Peter Kankowski for
1007        spotting this.
1010    Version 7.6 28-Jan-08
1011    ---------------------
1013    1.  A character class containing a very large number of characters with
1014        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
1015        overflow.
1017    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
1018        HAVE_LONG_LONG is not defined.
1020    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
1021        bring them up to date and include new features. This patch includes:
1023        - Fixed PH's badly added libz and libbz2 support.
1024        - Fixed a problem with static linking.
1025        - Added pcredemo. [But later removed - see 7 below.]
1026        - Fixed dftables problem and added an option.
1027        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
1028            HAVE_LONG_LONG.
1029        - Added readline support for pcretest.
1030        - Added an listing of the option settings after cmake has run.
1032    4.  A user submitted a patch to Makefile that makes it easy to create
1033        "pcre.dll" under mingw when using Configure/Make. I added stuff to
1034        Makefile.am that cause it to include this special target, without
1035        affecting anything else. Note that the same mingw target plus all
1036        the other distribution libraries and programs are now supported
1037        when configuring with CMake (see 6 below) instead of with
1038        Configure/Make.
1040    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
1041        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
1042        exported in the Windows port". It has not yet been confirmed that the patch
1043        solves the problem, but it does no harm.
1045    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
1046        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
1047        with CMake, and also correct the comment about stack recursion.
1049    7.  Remove the automatic building of pcredemo from the ./configure system and
1050        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
1051        of a program that users should build themselves after PCRE is installed, so
1052        building it automatically is not really right. What is more, it gave
1053        trouble in some build environments.
1055    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
1058    Version 7.5 10-Jan-08
1059    ---------------------
1061    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
1062        values in parens when parsing an RE using the C++ wrapper."
1064    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
1065        Characters greater than 255 were excluded from the class instead of being
1066        included.
1068    3.  The same bug as (2) above applied to negated POSIX classes such as
1069        [:^space:].
1071    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
1072        defined or documented. It seems to have been a typo for PCRE_STATIC, so
1073        I have changed it.
1075    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
1076        first named subpattern) and a construct such as (?&a) would reference the
1077        first named subpattern whose name started with "a" (in other words, the
1078        length check was missing). Both these problems are fixed. "Subpattern name
1079        expected" is now given for (?&) (a zero-length name), and this patch also
1080        makes it give the same error for \k'' (previously it complained that that
1081        was a reference to a non-existent subpattern).
1083    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
1084        this is right because (?- can be followed by option settings as well as by
1085        digits. I have, however, made the messages clearer.
1087    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
1088        than the number used in the conditional) now cause a compile-time error.
1089        This is actually not compatible with Perl, which accepts such patterns, but
1090        treats the conditional as always being FALSE (as PCRE used to), but it
1091        seems to me that giving a diagnostic is better.
1093    8.  Change "alphameric" to the more common word "alphanumeric" in comments
1094        and messages.
1096    9.  Fix two occurrences of "backslash" in comments that should have been
1097        "backspace".
1099    10. Remove two redundant lines of code that can never be obeyed (their function
1100        was moved elsewhere).
1102    11. The program that makes PCRE's Unicode character property table had a bug
1103        which caused it to generate incorrect table entries for sequences of
1104        characters that have the same character type, but are in different scripts.
1105        It amalgamated them into a single range, with the script of the first of
1106        them. In other words, some characters were in the wrong script. There were
1107        thirteen such cases, affecting characters in the following ranges:
1109          U+002b0 - U+002c1
1110          U+0060c - U+0060d
1111          U+0061e - U+00612
1112          U+0064b - U+0065e
1113          U+0074d - U+0076d
1114          U+01800 - U+01805
1115          U+01d00 - U+01d77
1116          U+01d9b - U+01dbf
1117          U+0200b - U+0200f
1118          U+030fc - U+030fe
1119          U+03260 - U+0327f
1120          U+0fb46 - U+0fbb1
1121          U+10450 - U+1049d
1123    12. The -o option (show only the matching part of a line) for pcregrep was not
1124        compatible with GNU grep in that, if there was more than one match in a
1125        line, it showed only the first of them. It now behaves in the same way as
1126        GNU grep.
1128    13. If the -o and -v options were combined for pcregrep, it printed a blank
1129        line for every non-matching line. GNU grep prints nothing, and pcregrep now
1130        does the same. The return code can be used to tell if there were any
1131        non-matching lines.
1133    14. Added --file-offsets and --line-offsets to pcregrep.
1135    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
1136        infinitely looping recursion. The bug was that positive lookaheads were not
1137        being skipped when checking for a possible empty match (negative lookaheads
1138        and both kinds of lookbehind were skipped).
1140    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
1141        inclusion of <windows.h> to before rather than after the definition of
1142        INVALID_FILE_ATTRIBUTES (patch from David Byron).
1144    17. Specifying a possessive quantifier with a specific limit for a Unicode
1145        character property caused pcre_compile() to compile bad code, which led at
1146        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
1147        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
1148        caused the error; without that there was no problem.
1150    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
1152    19. Added --enable-pcretest-libreadline.
1154    20. In pcrecpp.cc, the variable 'count' was incremented twice in
1155        RE::GlobalReplace(). As a result, the number of replacements returned was
1156        double what it should be. I removed one of the increments, but Craig sent a
1157        later patch that removed the other one (the right fix) and added unit tests
1158        that check the return values (which was not done before).
1160    21. Several CMake things:
1162        (1) Arranged that, when cmake is used on Unix, the libraries end up with
1163            the names libpcre and libpcreposix, not just pcre and pcreposix.
1165        (2) The above change means that pcretest and pcregrep are now correctly
1166            linked with the newly-built libraries, not previously installed ones.
1170    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
1171        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
1172        UTF-8 newline character). The key issue is that the pattern starts .*;
1173        this means that the match must be either at the beginning, or after a
1174        newline. The bug was in the code for advancing after a failed match and
1175        checking that the new position followed a newline. It was not taking
1176        account of UTF-8 characters correctly.
1178    23. PCRE was behaving differently from Perl in the way it recognized POSIX
1179        character classes. PCRE was not treating the sequence [:...:] as a
1180        character class unless the ... were all letters. Perl, however, seems to
1181        allow any characters between [: and :], though of course it rejects as
1182        unknown any "names" that contain non-letters, because all the known class
1183        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
1184        for example, whereas PCRE did not - it did not recognize a POSIX character
1185        class. This seemed a bit dangerous, so the code has been changed to be
1186        closer to Perl. The behaviour is not identical to Perl, because PCRE will
1187        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
1188        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
1189        Perl does, and where it didn't before.
1191    24. Rewrite so as to remove the single use of %n from pcregrep because in some
1192        Windows environments %n is disabled by default.
1195    Version 7.4 21-Sep-07
1196    ---------------------
1198    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
1199        means that a class such as [\s] counted as "explicit reference to CR or
1200        LF". That isn't really right - the whole point of the change was to try to
1201        help when there was an actual mention of one of the two characters. So now
1202        the change happens only if \r or \n (or a literal CR or LF) character is
1203        encountered.
1205    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
1206        of both had grown to the point where there were only 3 bits left.
1207        Fortunately, there was spare space in the data structure, and so I have
1208        moved the internal flags into a new 16-bit field to free up more option
1209        bits.
1211    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
1212        but did not set the internal JCHANGED flag - either of these is enough to
1213        control the way the "get" function works - but the PCRE_INFO_JCHANGED
1214        facility is supposed to tell if (?J) was ever used, so now (?J) at the
1215        start sets both bits.
1217    4.  Added options (at build time, compile time, exec time) to change \R from
1218        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
1220    5.  doc/pcresyntax.html was missing from the distribution.
1222    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
1223        compatibility, even though it is no longer used.
1225    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
1226        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
1227        windows.h file is present (where different names are used). [This was
1228        reversed later after testing - see 16 below.]
1230    8.  Changed all #include <config.h> to #include "config.h". There were also
1231        some further <pcre.h> cases that I changed to "pcre.h".
1233    9.  When pcregrep was used with the --colour option, it missed the line ending
1234        sequence off the lines that it output.
1236    10. It was pointed out to me that arrays of string pointers cause lots of
1237        relocations when a shared library is dynamically loaded. A technique of
1238        using a single long string with a table of offsets can drastically reduce
1239        these. I have refactored PCRE in four places to do this. The result is
1240        dramatic:
1242          Originally:                          290
1243          After changing UCP table:            187
1244          After changing error message table:   43
1245          After changing table of "verbs"       36
1246          After changing table of Posix names   22
1248        Thanks to the folks working on Gregex for glib for this insight.
1250    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
1251        unicode-properties was also set.
1253    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
1255    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
1256        checked only for CRLF.
1258    14. Added casts to pcretest.c to avoid compiler warnings.
1260    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
1262    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
1263        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
1264        entirely. This removes changes made in 7 above.
1266    17. The CMake files have been updated, and there is now more information about
1267        building with CMake in the NON-UNIX-USE document.
1270    Version 7.3 28-Aug-07
1271  ---------------------  ---------------------
1273   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 29  Version 7.3 05-Jul-07 Line 1295  Version 7.3 05-Jul-07
1295   4. Debugging: adjusted the names of opcodes for different kinds of parentheses   4. Debugging: adjusted the names of opcodes for different kinds of parentheses
1296      in debug output.      in debug output.
1298   5. Arrange to use "%I64d" instead of "%lld" for long printing in the pcrecpp   5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
1299      unittest when running under MinGW.      long printing in the pcrecpp unittest when running under MinGW.
1301   6. ESC_K was left out of the EBCDIC table.   6. ESC_K was left out of the EBCDIC table.
# Line 53  Version 7.3 05-Jul-07 Line 1319  Version 7.3 05-Jul-07
1319      pcreposix and pcrecpp parts of the library. These were overlooked when this      pcreposix and pcrecpp parts of the library. These were overlooked when this
1320      problem was solved for the main library.      problem was solved for the main library.
1322     9. There were some crude static tests to avoid integer overflow when computing
1323        the size of patterns that contain repeated groups with explicit upper
1324        limits. As the maximum quantifier is 65535, the maximum group length was
1325        set at 30,000 so that the product of these two numbers did not overflow a
1326        32-bit integer. However, it turns out that people want to use groups that
1327        are longer than 30,000 bytes (though not repeat them that many times).
1328        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1329        made it possible to implement the integer overflow checks in a much more
1330        dynamic way, which I have now done. The artificial limitation on group
1331        length has been removed - we now have only the limit on the total length of
1332        the compiled pattern, which depends on the LINK_SIZE setting.
1334    10. Fixed a bug in the documentation for get/copy named substring when
1335        duplicate names are permitted. If none of the named substrings are set, the
1336        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1337        empty string.
1339    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1340        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1341        because the ] is interpreted as the first data character and the
1342        terminating ] is not found. PCRE has been made compatible with Perl in this
1343        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1344        cause memory overwriting.
1346    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1347        string has been matched (to stop an infinite loop). It was not recognizing
1348        a conditional subpattern that could match an empty string if that
1349        subpattern was within another subpattern. For example, it looped when
1350        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1351        condition was not nested. This bug has been fixed.
1353    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1354        past the start of the subject in the presence of bytes with the top bit
1355        set, for example "\x8aBCD".
1357    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1358        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1360    14. Optimized (?!) to (*FAIL).
1362    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1363        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1364        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1365        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1366        does: it's just the validity check that is more restrictive.
1368    16. Inserted checks for integer overflows during escape sequence (backslash)
1369        processing, and also fixed erroneous offset values for syntax errors during
1370        backslash processing.
1372    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1373        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1375    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1376        caused an overrun.
1378    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1379        something other than just ASCII characters) inside a group that had an
1380        unlimited repeat caused a loop at compile time (while checking to see
1381        whether the group could match an empty string).
1383    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1384        [\P{Any}] did so. (Error in the code for printing property names.)
1386    21. An orphan \E inside a character class could cause a crash.
1388    22. A repeated capturing bracket such as (A)? could cause a wild memory
1389        reference during compilation.
1391    23. There are several functions in pcre_compile() that scan along a compiled
1392        expression for various reasons (e.g. to see if it's fixed length for look
1393        behind). There were bugs in these functions when a repeated \p or \P was
1394        present in the pattern. These operators have additional parameters compared
1395        with \d, etc, and these were not being taken into account when moving along
1396        the compiled data. Specifically:
1398        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1399            length.
1401        (b) An item such as \pL+ within a repeated group could cause crashes or
1402            loops.
1404        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1405            "reference to non-existent subpattern" error.
1407        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1409    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1410        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1412    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1414    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1415        character were causing crashes (broken optimization).
1417    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1418        \p or \P) caused a compile-time loop.
1420    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1421        break. For example, the unstudied pattern [\r\n]A does not match the string
1422        "\r\nA" because change 7.0/46 below moves the current point on by two
1423        characters after failing to match at the start. However, the pattern \nA
1424        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1425        the same is true. There doesn't seem any very clean way out of this, but
1426        what I have chosen to do makes the common cases work: PCRE now takes note
1427        of whether there can be an explicit match for \r or \n anywhere in the
1428        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1429        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1430        pattern has explicit CR or LF references.
1432    29. Added (*CR) etc for changing newline setting at start of pattern.
1435  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07
1436  ---------------------  ---------------------

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