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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.6 19-Jan-08  Version 8.12 15-Jan-2011
5    ------------------------
6    
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.
9    
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 fail. (The integer value
13        went into the wrong half of a long int.)
14    
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.
19    
20    4.  Another pcregrep bug caused similar problems if --colour was specified with
21        -M (multiline) and the pattern match finished with a line ending.
22    
23    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
24        matched in multiline mode, the following line was shown as part of the
25        match. This seems wrong, so I have changed it.
26    
27    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
28        the check for further matches in the same line (so they could be coloured)
29        to overrun the end of the current line. If another match was found, it was
30        incorrectly shown (and then shown again when found in the next line).
31    
32    7.  If pcregrep was compiled under Windows, there was a reference to the
33        function pcregrep_exit() before it was defined. I am assuming this was
34        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
35        reported by a user. I've moved the definition above the reference.
36    
37    
38    Version 8.11 10-Dec-2010
39    ------------------------
40    
41    1.  (*THEN) was not working properly if there were untried alternatives prior
42        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
43        backtracked to try for "b" instead of moving to the next alternative branch
44        at the same level (in this case, to look for "c"). The Perl documentation
45        is clear that when (*THEN) is backtracked onto, it goes to the "next
46        alternative in the innermost enclosing group".
47    
48    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
49        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
50        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
51        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
52        (*THEN).
53    
54    3.  If \s appeared in a character class, it removed the VT character from
55        the class, even if it had been included by some previous item, for example
56        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
57        of \s, but is part of the POSIX "space" class.)
58    
59    4.  A partial match never returns an empty string (because you can always
60        match an empty string at the end of the subject); however the checking for
61        an empty string was starting at the "start of match" point. This has been
62        changed to the "earliest inspected character" point, because the returned
63        data for a partial match starts at this character. This means that, for
64        example, /(?<=abc)def/ gives a partial match for the subject "abc"
65        (previously it gave "no match").
66    
67    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
68        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
69        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
70        has an implication that the given string is incomplete (because a partial
71        match is preferred over a full match). For this reason, these items now
72        give a partial match in this situation. [Aside: previously, the one case
73        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
74        match rather than a full match, which was wrong by the old rules, but is
75        now correct.]
76    
77    6.  There was a bug in the handling of #-introduced comments, recognized when
78        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
79        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
80        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
81        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
82        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
83        places in pcre_compile().
84    
85    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
86        comments when looking ahead for named forward references to subpatterns,
87        the only newline sequence it recognized was NL. It now handles newlines
88        according to the set newline convention.
89    
90    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
91        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
92        cater for a lack of strerror(). These oversights have been fixed.
93    
94    9.  Added --match-limit and --recursion-limit to pcregrep.
95    
96    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
97    
98    11. When the -o option was used, pcregrep was setting a return code of 1, even
99        when matches were found, and --line-buffered was not being honoured.
100    
101    12. Added an optional parentheses number to the -o and --only-matching options
102        of pcregrep.
103    
104    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
105        can match an empty string. The code to do it in pcretest and pcredemo
106        needed fixing:
107    
108        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
109            only one byte after an empty string match just before CRLF (this case
110            just got forgotten; "any" and "anycrlf" were OK).
111    
112        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
113            mode when an empty string match preceded an ASCII character followed by
114            a non-ASCII character. (The code for advancing by one character rather
115            than one byte was nonsense.)
116    
117        (c) The pcredemo.c sample program did not have any code at all to handle
118            the cases when CRLF is a valid newline sequence.
119    
120    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
121        as a starting offset was within the subject string. There is now a new
122        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
123        negative or greater than the length of the string. In order to test this,
124        pcretest is extended to allow the setting of negative starting offsets.
125    
126    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
127        starting offset points to the beginning of a UTF-8 character was
128        unnecessarily clumsy. I tidied it up.
129    
130    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
131        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
132    
133    17. Nobody had reported that the --include_dir option, which was added in
134        release 7.7 should have been called --include-dir (hyphen, not underscore)
135        for compatibility with GNU grep. I have changed it to --include-dir, but
136        left --include_dir as an undocumented synonym, and the same for
137        --exclude-dir, though that is not available in GNU grep, at least as of
138        release 2.5.4.
139    
140    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
141        characters from a string of bytes) have been redefined so as not to use
142        loops, in order to improve performance in some environments. At the same
143        time, I abstracted some of the common code into auxiliary macros to save
144        repetition (this should not affect the compiled code).
145    
146    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
147        compile-time error is now given if \c is not followed by an ASCII
148        character, that is, a byte less than 128. (In EBCDIC mode, the code is
149        different, and any byte value is allowed.)
150    
151    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
152        START_OPTIMIZE option, which is now allowed at compile time - but just
153        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
154        to pcregrep and other applications that have no direct access to PCRE
155        options. The new /Y option in pcretest sets this option when calling
156        pcre_compile().
157    
158    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
159        back references. Groups containing recursive back references were forced to
160        be atomic by that change, but in the case of named groups, the amount of
161        memory required was incorrectly computed, leading to "Failed: internal
162        error: code overflow". This has been fixed.
163    
164    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
165        pcretest.c, to avoid build problems in some Borland environments.
166    
167    
168    Version 8.10 25-Jun-2010
169    ------------------------
170    
171    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
172        THEN.
173    
174    2.  (*ACCEPT) was not working when inside an atomic group.
175    
176    3.  Inside a character class, \B is treated as a literal by default, but
177        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
178        causes the error). The code is unchanged, but I tidied the documentation.
179    
180    4.  Inside a character class, PCRE always treated \R and \X as literals,
181        whereas Perl faults them if its -w option is set. I have changed PCRE so
182        that it faults them when PCRE_EXTRA is set.
183    
184    5.  Added support for \N, which always matches any character other than
185        newline. (It is the same as "." when PCRE_DOTALL is not set.)
186    
187    6.  When compiling pcregrep with newer versions of gcc which may have
188        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
189        declared with attribute warn_unused_result" were given. Just casting the
190        result to (void) does not stop the warnings; a more elaborate fudge is
191        needed. I've used a macro to implement this.
192    
193    7.  Minor change to pcretest.c to avoid a compiler warning.
194    
195    8.  Added four artifical Unicode properties to help with an option to make
196        \s etc use properties (see next item). The new properties are: Xan
197        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
198    
199    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
200        use Unicode properties. (*UCP) at the start of a pattern can be used to set
201        this option. Modified pcretest to add /W to test this facility. Added
202        REG_UCP to make it available via the POSIX interface.
203    
204    10. Added --line-buffered to pcregrep.
205    
206    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
207        studied, and the match started with a letter with a code point greater than
208        127 whose first byte was different to the first byte of the other case of
209        the letter, the other case of this starting letter was not recognized
210        (#976).
211    
212    12. If a pattern that was studied started with a repeated Unicode property
213        test, for example, \p{Nd}+, there was the theoretical possibility of
214        setting up an incorrect bitmap of starting bytes, but fortunately it could
215        not have actually happened in practice until change 8 above was made (it
216        added property types that matched character-matching opcodes).
217    
218    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
219        possible starting bytes for non-anchored patterns.
220    
221    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
222        \R, and also a number of cases that involve Unicode properties, both
223        explicit and implicit when PCRE_UCP is set.
224    
225    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
226        input, it could crash or give wrong results if characters with values
227        greater than 0xc0 were present in the subject string. (Detail: it assumed
228        UTF-8 input when processing these items.)
229    
230    16. Added a lot of (int) casts to avoid compiler warnings in systems where
231        size_t is 64-bit (#991).
232    
233    17. Added a check for running out of memory when PCRE is compiled with
234        --disable-stack-for-recursion (#990).
235    
236    18. If the last data line in a file for pcretest does not have a newline on
237        the end, a newline was missing in the output.
238    
239    19. The default pcre_chartables.c file recognizes only ASCII characters (values
240        less than 128) in its various bitmaps. However, there is a facility for
241        generating tables according to the current locale when PCRE is compiled. It
242        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
243        characters, are recognized by isspace() and therefore were getting set in
244        these tables, and indeed these tables seem to approximate to ISO 8859. This
245        caused a problem in UTF-8 mode when pcre_study() was used to create a list
246        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
247        which of course cannot start UTF-8 characters. I have changed the code so
248        that only real ASCII characters (less than 128) and the correct starting
249        bytes for UTF-8 encodings are set for characters greater than 127 when in
250        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
251        altogether.)
252    
253    20. Added the /T option to pcretest so as to be able to run tests with non-
254        standard character tables, thus making it possible to include the tests
255        used for 19 above in the standard set of tests.
256    
257    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
258        reference to a subpattern the other side of a comment that contains an
259        opening parenthesis caused either an internal compiling error, or a
260        reference to the wrong subpattern.
261    
262    
263    Version 8.02 19-Mar-2010
264    ------------------------
265    
266    1.  The Unicode data tables have been updated to Unicode 5.2.0.
267    
268    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
269        configured.
270    
271    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
272        original author of that file, following a query about its status.
273    
274    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
275        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
276    
277    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
278        quantifier applied to a forward-referencing subroutine call, could compile
279        incorrect code or give the error "internal error: previously-checked
280        referenced subpattern not found".
281    
282    6.  Both MS Visual Studio and Symbian OS have problems with initializing
283        variables to point to external functions. For these systems, therefore,
284        pcre_malloc etc. are now initialized to local functions that call the
285        relevant global functions.
286    
287    7.  There were two entries missing in the vectors called coptable and poptable
288        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
289        I've fixed the data, and added a kludgy way of testing at compile time that
290        the lengths are correct (equal to the number of opcodes).
291    
292    8.  Following on from 7, I added a similar kludge to check the length of the
293        eint vector in pcreposix.c.
294    
295    9.  Error texts for pcre_compile() are held as one long string to avoid too
296        much relocation at load time. To find a text, the string is searched,
297        counting zeros. There was no check for running off the end of the string,
298        which could happen if a new error number was added without updating the
299        string.
300    
301    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
302    
303    11. \K was not working if it appeared in an atomic group or in a group that
304        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
305        \K is "not well defined" if used in an assertion. PCRE now accepts it if
306        the assertion is positive, but not if it is negative.
307    
308    12. Change 11 fortuitously reduced the size of the stack frame used in the
309        "match()" function of pcre_exec.c by one pointer. Forthcoming
310        implementation of support for (*MARK) will need an extra pointer on the
311        stack; I have reserved it now, so that the stack frame size does not
312        decrease.
313    
314    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
315        item in branch that calls a recursion is a subroutine call - as in the
316        second branch in the above example - was incorrectly given the compile-
317        time error "recursive call could loop indefinitely" because pcre_compile()
318        was not correctly checking the subroutine for matching a non-empty string.
319    
320    14. The checks for overrunning compiling workspace could trigger after an
321        overrun had occurred. This is a "should never occur" error, but it can be
322        triggered by pathological patterns such as hundreds of nested parentheses.
323        The checks now trigger 100 bytes before the end of the workspace.
324    
325    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
326    
327    
328    Version 8.01 19-Jan-2010
329    ------------------------
330    
331    1.  If a pattern contained a conditional subpattern with only one branch (in
332        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
333        computed the wrong minimum data length (which is of course zero for such
334        subpatterns). This could cause incorrect "no match" results.
335    
336    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
337        the pattern is reset in the first branch, pcre_compile() failed with
338        "internal error: code overflow at offset...". This happened only when
339        the reset was to the original external option setting. (An optimization
340        abstracts leading options settings into an external setting, which was the
341        cause of this.)
342    
343    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
344        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
345        assertion pattern did not match (meaning that the assertion was true), it
346        was incorrectly treated as false if the SKIP had been reached during the
347        matching. This also applied to assertions used as conditions.
348    
349    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
350        assertion subpattern, including such a pattern used as a condition,
351        unpredictable results occurred, instead of the error return
352        PCRE_ERROR_DFA_UITEM.
353    
354    5.  The C++ GlobalReplace function was not working like Perl for the special
355        situation when an empty string is matched. It now does the fancy magic
356        stuff that is necessary.
357    
358    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
359        removed. (These were left over from very, very early versions of PCRE.)
360    
361    7.  Some cosmetic changes to the code to make life easier when compiling it
362        as part of something else:
363    
364        (a) Change DEBUG to PCRE_DEBUG.
365    
366        (b) In pcre_compile(), rename the member of the "branch_chain" structure
367            called "current" as "current_branch", to prevent a collision with the
368            Linux macro when compiled as a kernel module.
369    
370        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
371            prevent a collision with the Linux macro when compiled as a kernel
372            module.
373    
374    8.  In pcre_compile() there are some checks for integer overflows that used to
375        cast potentially large values to (double). This has been changed to that
376        when building, a check for int64_t is made, and if it is found, it is used
377        instead, thus avoiding the use of floating point arithmetic. (There is no
378        other use of FP in PCRE.) If int64_t is not found, the fallback is to
379        double.
380    
381    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
382        2005 (difference between two addresses compared to an unsigned value).
383    
384    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
385        custom one, because of the following reported problem in Windows:
386    
387          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
388              under Win32.
389          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
390              therefore missing the function definition.
391          - The compiler thus generates a "C" signature for the test function.
392          - The linker fails to find the "C" function.
393          - PCRE fails to configure if asked to do so against libbz2.
394    
395    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
396        messages were output:
397    
398          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
399          rerunning libtoolize, to keep the correct libtool macros in-tree.
400          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
401    
402        I have done both of these things.
403    
404    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
405        most of the time, it *can* run out if it is given a pattern that contains a
406        runaway infinite recursion. I updated the discussion in the pcrestack man
407        page.
408    
409    13. Now that we have gone to the x.xx style of version numbers, the minor
410        version may start with zero. Using 08 or 09 is a bad idea because users
411        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
412        interpreted as invalid octal numbers. I've updated the previous comment in
413        configure.ac, and also added a check that gives an error if 08 or 09 are
414        used.
415    
416    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
417        causing partial matching to fail when the end of the subject matched \W
418        in a UTF-8 pattern where \W was quantified with a minimum of 3.
419    
420    15. There were some discrepancies between the declarations in pcre_internal.h
421        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
422        their definitions. The declarations used "const uschar *" and the
423        definitions used USPTR. Even though USPTR is normally defined as "const
424        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
425        reported that: "This difference in casting confuses some C++ compilers, for
426        example, SunCC recognizes above declarations as different functions and
427        generates broken code for hbpcre." I have changed the declarations to use
428        USPTR.
429    
430    16. GNU libtool is named differently on some systems. The autogen.sh script now
431        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
432        (FreeBSD).
433    
434    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
435        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
436        comment: "Figure out how to create a longlong from a string: strtoll and
437        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
438        instance, but it only takes 2 args instead of 3!"
439    
440    18. A subtle bug concerned with back references has been fixed by a change of
441        specification, with a corresponding code fix. A pattern such as
442        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
443        refers, was giving matches when it shouldn't. For example, xa=xaaa would
444        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
445        same bug. Such groups have to be quantified to be useful, or contained
446        inside another quantified group. (If there's no repetition, the reference
447        can never match.) The problem arises because, having left the group and
448        moved on to the rest of the pattern, a later failure that backtracks into
449        the group uses the captured value from the final iteration of the group
450        rather than the correct earlier one. I have fixed this in PCRE by forcing
451        any group that contains a reference to itself to be an atomic group; that
452        is, there cannot be any backtracking into it once it has completed. This is
453        similar to recursive and subroutine calls.
454    
455    
456    Version 8.00 19-Oct-09
457    ----------------------
458    
459    1.  The table for translating pcre_compile() error codes into POSIX error codes
460        was out-of-date, and there was no check on the pcre_compile() error code
461        being within the table. This could lead to an OK return being given in
462        error.
463    
464    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
465        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
466        in a Windows environment.
467    
468    3.  The pcregrep --count option prints the count for each file even when it is
469        zero, as does GNU grep. However, pcregrep was also printing all files when
470        --files-with-matches was added. Now, when both options are given, it prints
471        counts only for those files that have at least one match. (GNU grep just
472        prints the file name in this circumstance, but including the count seems
473        more useful - otherwise, why use --count?) Also ensured that the
474        combination -clh just lists non-zero counts, with no names.
475    
476    4.  The long form of the pcregrep -F option was incorrectly implemented as
477        --fixed_strings instead of --fixed-strings. This is an incompatible change,
478        but it seems right to fix it, and I didn't think it was worth preserving
479        the old behaviour.
480    
481    5.  The command line items --regex=pattern and --regexp=pattern were not
482        recognized by pcregrep, which required --regex pattern or --regexp pattern
483        (with a space rather than an '='). The man page documented the '=' forms,
484        which are compatible with GNU grep; these now work.
485    
486    6.  No libpcreposix.pc file was created for pkg-config; there was just
487        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
488    
489    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
490        when UCP support is not needed, by modifying the Python script that
491        generates it from Unicode data files. This should not matter if the module
492        is correctly used as a library, but I received one complaint about 50K of
493        unwanted data. My guess is that the person linked everything into his
494        program rather than using a library. Anyway, it does no harm.
495    
496    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
497        was a minimum greater than 1 for a wide character in a possessive
498        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
499        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
500        character. Chaos in the form of incorrect output or a compiling loop could
501        result.
502    
503    9.  The restrictions on what a pattern can contain when partial matching is
504        requested for pcre_exec() have been removed. All patterns can now be
505        partially matched by this function. In addition, if there are at least two
506        slots in the offset vector, the offset of the earliest inspected character
507        for the match and the offset of the end of the subject are set in them when
508        PCRE_ERROR_PARTIAL is returned.
509    
510    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
511        synonymous with PCRE_PARTIAL, for backwards compatibility, and
512        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
513        and may be more useful for multi-segment matching.
514    
515    11. Partial matching with pcre_exec() is now more intuitive. A partial match
516        used to be given if ever the end of the subject was reached; now it is
517        given only if matching could not proceed because another character was
518        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
519        string "Z", which now yields "no match" instead of "partial match". In the
520        case of pcre_dfa_exec(), "no match" is given if every matching path for the
521        final character ended with (*FAIL).
522    
523    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
524        if the pattern had a "must contain" character that was already found in the
525        earlier partial match, unless partial matching was again requested. For
526        example, with the pattern /dog.(body)?/, the "must contain" character is
527        "g". If the first part-match was for the string "dog", restarting with
528        "sbody" failed. This bug has been fixed.
529    
530    13. The string returned by pcre_dfa_exec() after a partial match has been
531        changed so that it starts at the first inspected character rather than the
532        first character of the match. This makes a difference only if the pattern
533        starts with a lookbehind assertion or \b or \B (\K is not supported by
534        pcre_dfa_exec()). It's an incompatible change, but it makes the two
535        matching functions compatible, and I think it's the right thing to do.
536    
537    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
538        so that the demonstration program is easily available in environments where
539        PCRE has not been installed from source.
540    
541    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
542        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
543        library.
544    
545    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
546        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
547        is not the first non-POSIX option to be added. Clearly some people find
548        these options useful.
549    
550    17. If a caller to the POSIX matching function regexec() passes a non-zero
551        value for nmatch with a NULL value for pmatch, the value of
552        nmatch is forced to zero.
553    
554    18. RunGrepTest did not have a test for the availability of the -u option of
555        the diff command, as RunTest does. It now checks in the same way as
556        RunTest, and also checks for the -b option.
557    
558    19. If an odd number of negated classes containing just a single character
559        interposed, within parentheses, between a forward reference to a named
560        subpattern and the definition of the subpattern, compilation crashed with
561        an internal error, complaining that it could not find the referenced
562        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
563        [The bug was that it was starting one character too far in when skipping
564        over the character class, thus treating the ] as data rather than
565        terminating the class. This meant it could skip too much.]
566    
567    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
568        /g option in pcretest when the pattern contains \K, which makes it possible
569        to have an empty string match not at the start, even when the pattern is
570        anchored. Updated pcretest and pcredemo to use this option.
571    
572    21. If the maximum number of capturing subpatterns in a recursion was greater
573        than the maximum at the outer level, the higher number was returned, but
574        with unset values at the outer level. The correct (outer level) value is
575        now given.
576    
577    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
578        PCRE did not set those parentheses (unlike Perl). I have now found a way to
579        make it do so. The string so far is captured, making this feature
580        compatible with Perl.
581    
582    23. The tests have been re-organized, adding tests 11 and 12, to make it
583        possible to check the Perl 5.10 features against Perl 5.10.
584    
585    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
586        pattern matches a fixed length string. PCRE did not allow this; now it
587        does. Neither allows recursion.
588    
589    25. I finally figured out how to implement a request to provide the minimum
590        length of subject string that was needed in order to match a given pattern.
591        (It was back references and recursion that I had previously got hung up
592        on.) This code has now been added to pcre_study(); it finds a lower bound
593        to the length of subject needed. It is not necessarily the greatest lower
594        bound, but using it to avoid searching strings that are too short does give
595        some useful speed-ups. The value is available to calling programs via
596        pcre_fullinfo().
597    
598    26. While implementing 25, I discovered to my embarrassment that pcretest had
599        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
600        study optimizations had never been tested with that matching function.
601        Oops. What is worse, even when it was passed study data, there was a bug in
602        pcre_dfa_exec() that meant it never actually used it. Double oops. There
603        were also very few tests of studied patterns with pcre_dfa_exec().
604    
605    27. If (?| is used to create subpatterns with duplicate numbers, they are now
606        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
607        on the other side of the coin, they are no longer allowed to have different
608        names, because these cannot be distinguished in PCRE, and this has caused
609        confusion. (This is a difference from Perl.)
610    
611    28. When duplicate subpattern names are present (necessarily with different
612        numbers, as required by 27 above), and a test is made by name in a
613        conditional pattern, either for a subpattern having been matched, or for
614        recursion in such a pattern, all the associated numbered subpatterns are
615        tested, and the overall condition is true if the condition is true for any
616        one of them. This is the way Perl works, and is also more like the way
617        testing by number works.
618    
619    
620    Version 7.9 11-Apr-09
621    ---------------------
622    
623    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
624        (pcretest), all targets were linked against these libraries. This included
625        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
626        libraries. This caused unwanted dependencies to be created. This problem
627        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
628        pcretest is linked with readline.
629    
630    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
631        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
632        moved outside it again, because FALSE and TRUE are already defined in AIX,
633        but BOOL is not.
634    
635    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
636        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
637    
638    4.  The pcregrep documentation said spaces were inserted as well as colons (or
639        hyphens) following file names and line numbers when outputting matching
640        lines. This is not true; no spaces are inserted. I have also clarified the
641        wording for the --colour (or --color) option.
642    
643    5.  In pcregrep, when --colour was used with -o, the list of matching strings
644        was not coloured; this is different to GNU grep, so I have changed it to be
645        the same.
646    
647    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
648        each matching line was coloured. Now it goes on to look for further matches
649        of any of the test patterns, which is the same behaviour as GNU grep.
650    
651    7.  A pattern that could match an empty string could cause pcregrep to loop; it
652        doesn't make sense to accept an empty string match in pcregrep, so I have
653        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
654        seems to be how GNU grep behaves.
655    
656    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
657        start or after a newline", because the conditional assertion was not being
658        correctly handled. The rule now is that both the assertion and what follows
659        in the first alternative must satisfy the test.
660    
661    9.  If auto-callout was enabled in a pattern with a conditional group whose
662        condition was an assertion, PCRE could crash during matching, both with
663        pcre_exec() and pcre_dfa_exec().
664    
665    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
666        used for matching.
667    
668    11. Unicode property support in character classes was not working for
669        characters (bytes) greater than 127 when not in UTF-8 mode.
670    
671    12. Added the -M command line option to pcretest.
672    
673    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
674    
675    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
676    
677    16. Added comments and documentation about mis-use of no_arg in the C++
678        wrapper.
679    
680    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
681        from Martin Jerabek that uses macro names for all relevant character and
682        string constants.
683    
684    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
685        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
686        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
687        these, but not everybody uses configure.
688    
689    19. A conditional group that had only one branch was not being correctly
690        recognized as an item that could match an empty string. This meant that an
691        enclosing group might also not be so recognized, causing infinite looping
692        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
693        with the subject "ab", where knowledge that the repeated group can match
694        nothing is needed in order to break the loop.
695    
696    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
697        exec(), but without supplying a callout function, matching went wrong.
698    
699    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
700        leak if the size of the offset vector was greater than 30. When the vector
701        is smaller, the saved offsets during recursion go onto a local stack
702        vector, but for larger vectors malloc() is used. It was failing to free
703        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
704        error, in fact).
705    
706    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
707        heapframe that is used only when UTF-8 support is enabled. This caused no
708        problem, but was untidy.
709    
710    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
711        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
712        included within another project.
713    
714    24. Steven Van Ingelgem's patches to add more options to the CMake support,
715        slightly modified by me:
716    
717          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
718              not building pcregrep.
719    
720          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
721              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
722    
723    25. Forward references, both numeric and by name, in patterns that made use of
724        duplicate group numbers, could behave incorrectly or give incorrect errors,
725        because when scanning forward to find the reference group, PCRE was not
726        taking into account the duplicate group numbers. A pattern such as
727        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
728    
729    26. Changed a few more instances of "const unsigned char *" to USPTR, making
730        the feature of a custom pointer more persuasive (as requested by a user).
731    
732    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
733        pcretest.c, inside #ifndefs, because it seems they are sometimes already
734        pre-defined.
735    
736    28. Added support for (*UTF8) at the start of a pattern.
737    
738    29. Arrange for flags added by the "release type" setting in CMake to be shown
739        in the configuration summary.
740    
741    
742    Version 7.8 05-Sep-08
743    ---------------------
744    
745    1.  Replaced UCP searching code with optimized version as implemented for Ad
746        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
747        stage table and inline lookup instead of a function, giving speed ups of 2
748        to 5 times on some simple patterns that I tested. Permission was given to
749        distribute the MultiStage2.py script that generates the tables (it's not in
750        the tarball, but is in the Subversion repository).
751    
752    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
753        scripts.
754    
755    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
756        a group with a zero qualifier. The result of the study could be incorrect,
757        or the function might crash, depending on the pattern.
758    
759    4.  Caseless matching was not working for non-ASCII characters in back
760        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
761        It now works when Unicode Property Support is available.
762    
763    5.  In pcretest, an escape such as \x{de} in the data was always generating
764        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
765        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
766        truncation.
767    
768    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
769    
770    7.  Added two (int) casts to pcregrep when printing the difference of two
771        pointers, in case they are 64-bit values.
772    
773    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
774        test 2 if it fails.
775    
776    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
777        and a #define of that name to empty if it is not externally set. This is to
778        allow users of MSVC to set it if necessary.
779    
780    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
781        the convenience functions in the pcre_get.c source file.
782    
783    11. An option change at the start of a pattern that had top-level alternatives
784        could cause overwriting and/or a crash. This command provoked a crash in
785        some environments:
786    
787          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
788    
789        This potential security problem was recorded as CVE-2008-2371.
790    
791    12. For a pattern where the match had to start at the beginning or immediately
792        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
793        pcre_dfa_exec() could read past the end of the passed subject if there was
794        no match. To help with detecting such bugs (e.g. with valgrind), I modified
795        pcretest so that it places the subject at the end of its malloc-ed buffer.
796    
797    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
798        exec() might read past the end of the data buffer in UTF-8 mode.
799    
800    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
801        the data contained the byte 0x85 as part of a UTF-8 character within its
802        first line. This applied both to normal and DFA matching.
803    
804    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
805        /^[^d]*?$/8 failed to match "abc".
806    
807    16. Added a missing copyright notice to pcrecpp_internal.h.
808    
809    17. Make it more clear in the documentation that values returned from
810        pcre_exec() in ovector are byte offsets, not character counts.
811    
812    18. Tidied a few places to stop certain compilers from issuing warnings.
813    
814    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
815        supplied by Stefan Weber. I made a further small update for 7.8 because
816        there is a change of source arrangements: the pcre_searchfuncs.c module is
817        replaced by pcre_ucd.c.
818    
819    
820    Version 7.7 07-May-08
821    ---------------------
822    
823    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
824        a string to a long long, pretend we don't even have a long long." This is
825        done by checking for the strtoq, strtoll, and _strtoi64 functions.
826    
827    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
828        pre-7.6 versions, which defined a global no_arg variable instead of putting
829        it in the RE class. (See also #8 below.)
830    
831    3.  Remove a line of dead code, identified by coverity and reported by Nuno
832        Lopes.
833    
834    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
835    
836        (1) The include/exclude patterns were being applied to the whole pathnames
837            of files, instead of just to the final components.
838    
839        (2) If there was more than one level of directory, the subdirectories were
840            skipped unless they satisfied the include/exclude conditions. This is
841            inconsistent with GNU grep (and could even be seen as contrary to the
842            pcregrep specification - which I improved to make it absolutely clear).
843            The action now is always to scan all levels of directory, and just
844            apply the include/exclude patterns to regular files.
845    
846    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
847        --exclude_dir in the tests to avoid scanning .svn directories.
848    
849    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
850        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
851        doesn't support NULs in patterns.
852    
853    7.  Added some missing "const"s to declarations of static tables in
854        pcre_compile.c and pcre_dfa_exec.c.
855    
856    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
857        caused by fix #2  above. (Subsequently also a second patch to fix the
858        first patch. And a third patch - this was a messy problem.)
859    
860    9.  Applied Craig's patch to remove the use of push_back().
861    
862    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
863        matching function regexec().
864    
865    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
866        which, however, unlike Perl's \g{...}, are subroutine calls, not back
867        references. PCRE supports relative numbers with this syntax (I don't think
868        Oniguruma does).
869    
870    12. Previously, a group with a zero repeat such as (...){0} was completely
871        omitted from the compiled regex. However, this means that if the group
872        was called as a subroutine from elsewhere in the pattern, things went wrong
873        (an internal error was given). Such groups are now left in the compiled
874        pattern, with a new opcode that causes them to be skipped at execution
875        time.
876    
877    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
878        to the way PCRE behaves:
879    
880        (a) A lone ] character is dis-allowed (Perl treats it as data).
881    
882        (b) A back reference to an unmatched subpattern matches an empty string
883            (Perl fails the current match path).
884    
885        (c) A data ] in a character class must be notated as \] because if the
886            first data character in a class is ], it defines an empty class. (In
887            Perl it is not possible to have an empty class.) The empty class []
888            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
889            The negative empty class [^] matches any one character, independently
890            of the DOTALL setting.
891    
892    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
893        non-existent subpattern following a character class starting with ']' and
894        containing () gave an internal compiling error instead of "reference to
895        non-existent subpattern". Fortunately, when the pattern did exist, the
896        compiled code was correct. (When scanning forwards to check for the
897        existencd of the subpattern, it was treating the data ']' as terminating
898        the class, so got the count wrong. When actually compiling, the reference
899        was subsequently set up correctly.)
900    
901    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
902        it was being rejected as not supported by pcre_dfa_exec(), even though
903        other assertions are supported. I have made pcre_dfa_exec() support
904        (*FAIL).
905    
906    16. The implementation of 13c above involved the invention of a new opcode,
907        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
908        cannot be changed at match time, I realized I could make a small
909        improvement to matching performance by compiling OP_ALLANY instead of
910        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
911        on the OP_ANY path.
912    
913    17. Compiling pcretest on Windows with readline support failed without the
914        following two fixes: (1) Make the unistd.h include conditional on
915        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
916    
917    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
918        ncurses library to be included for pcretest when ReadLine support is
919        requested, but also to allow for it to be overridden. This patch came from
920        Daniel Bergström.
921    
922    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
923        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
924        any errors with the current Unicode tables. Thanks to Peter Kankowski for
925        spotting this.
926    
927    
928    Version 7.6 28-Jan-08
929  ---------------------  ---------------------
930    
931  1.  A character class containing a very large number of characters with  1.  A character class containing a very large number of characters with
932      codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer      codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
933      overflow.      overflow.
934    
935  2.  Patch to cut out the "long long" test in pcrecpp_unittest when  2.  Patch to cut out the "long long" test in pcrecpp_unittest when
936      HAVE_LONG_LONG is not defined.      HAVE_LONG_LONG is not defined.
937    
938  3.  Applied Christian Ehrlicher's patch to update the CMake build files to  3.  Applied Christian Ehrlicher's patch to update the CMake build files to
939      bring them up to date and include new features. This patch includes:      bring them up to date and include new features. This patch includes:
940    
941      - Fixed PH's badly added libz and libbz2 support.      - Fixed PH's badly added libz and libbz2 support.
942      - Fixed a problem with static linking.      - Fixed a problem with static linking.
943      - Added pcredemo.      - Added pcredemo. [But later removed - see 7 below.]
944      - Fixed dftables problem and added an option.      - Fixed dftables problem and added an option.
945      - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and      - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
946          HAVE_LONG_LONG.          HAVE_LONG_LONG.
947      - Added readline support for pcretest.      - Added readline support for pcretest.
948      - Added an listing of the option settings after cmake has run.      - Added an listing of the option settings after cmake has run.
949    
950  4.  A user submitted a patch to Makefile that makes it easy to created a dll  4.  A user submitted a patch to Makefile that makes it easy to create
951      under mingw. I added stuff to Makefile.am that cause it to include this      "pcre.dll" under mingw when using Configure/Make. I added stuff to
952      special target, without affecting anything else.      Makefile.am that cause it to include this special target, without
953        affecting anything else. Note that the same mingw target plus all
954        the other distribution libraries and programs are now supported
955        when configuring with CMake (see 6 below) instead of with
956        Configure/Make.
957    
958  5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.  5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
959      This is an attempt to solve the reported problem "pcrecpp::no_arg is not      This is an attempt to solve the reported problem "pcrecpp::no_arg is not
960      exported in the Windows port". It has not yet been confirmed that the patch      exported in the Windows port". It has not yet been confirmed that the patch
961      solves the problem, but it does no harm.      solves the problem, but it does no harm.
962    
963    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
964        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
965        with CMake, and also correct the comment about stack recursion.
966    
967    7.  Remove the automatic building of pcredemo from the ./configure system and
968        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
969        of a program that users should build themselves after PCRE is installed, so
970        building it automatically is not really right. What is more, it gave
971        trouble in some build environments.
972    
973    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
974    
975    
976  Version 7.5 10-Jan-08  Version 7.5 10-Jan-08

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