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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 8.10 03 May-2010
5    ------------------------
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
10    2.  (*ACCEPT) was not working when inside an atomic group.
12    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
23    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
29    7.  Minor change to pcretest.c to avoid a compiler warning.
32    Version 8.02 19-Mar-2010
33    ------------------------
35    1.  The Unicode data tables have been updated to Unicode 5.2.0.
37    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
38        configured.
40    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
41        original author of that file, following a query about its status.
43    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
44        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
46    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
47        quantifier applied to a forward-referencing subroutine call, could compile
48        incorrect code or give the error "internal error: previously-checked
49        referenced subpattern not found".
51    6.  Both MS Visual Studio and Symbian OS have problems with initializing
52        variables to point to external functions. For these systems, therefore,
53        pcre_malloc etc. are now initialized to local functions that call the
54        relevant global functions.
56    7.  There were two entries missing in the vectors called coptable and poptable
57        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
58        I've fixed the data, and added a kludgy way of testing at compile time that
59        the lengths are correct (equal to the number of opcodes).
61    8.  Following on from 7, I added a similar kludge to check the length of the
62        eint vector in pcreposix.c.
64    9.  Error texts for pcre_compile() are held as one long string to avoid too
65        much relocation at load time. To find a text, the string is searched,
66        counting zeros. There was no check for running off the end of the string,
67        which could happen if a new error number was added without updating the
68        string.
70    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
72    11. \K was not working if it appeared in an atomic group or in a group that
73        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
74        \K is "not well defined" if used in an assertion. PCRE now accepts it if
75        the assertion is positive, but not if it is negative.
77    12. Change 11 fortuitously reduced the size of the stack frame used in the
78        "match()" function of pcre_exec.c by one pointer. Forthcoming
79        implementation of support for (*MARK) will need an extra pointer on the
80        stack; I have reserved it now, so that the stack frame size does not
81        decrease.
83    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
84        item in branch that calls a recursion is a subroutine call - as in the
85        second branch in the above example - was incorrectly given the compile-
86        time error "recursive call could loop indefinitely" because pcre_compile()
87        was not correctly checking the subroutine for matching a non-empty string.
89    14. The checks for overrunning compiling workspace could trigger after an
90        overrun had occurred. This is a "should never occur" error, but it can be
91        triggered by pathological patterns such as hundreds of nested parentheses.
92        The checks now trigger 100 bytes before the end of the workspace.
94    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
97    Version 8.01 19-Jan-2010
98    ------------------------
100    1.  If a pattern contained a conditional subpattern with only one branch (in
101        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
102        computed the wrong minimum data length (which is of course zero for such
103        subpatterns). This could cause incorrect "no match" results.
105    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
106        the pattern is reset in the first branch, pcre_compile() failed with
107        "internal error: code overflow at offset...". This happened only when
108        the reset was to the original external option setting. (An optimization
109        abstracts leading options settings into an external setting, which was the
110        cause of this.)
112    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
113        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
114        assertion pattern did not match (meaning that the assertion was true), it
115        was incorrectly treated as false if the SKIP had been reached during the
116        matching. This also applied to assertions used as conditions.
118    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
119        assertion subpattern, including such a pattern used as a condition,
120        unpredictable results occurred, instead of the error return
123    5.  The C++ GlobalReplace function was not working like Perl for the special
124        situation when an empty string is matched. It now does the fancy magic
125        stuff that is necessary.
127    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
128        removed. (These were left over from very, very early versions of PCRE.)
130    7.  Some cosmetic changes to the code to make life easier when compiling it
131        as part of something else:
133        (a) Change DEBUG to PCRE_DEBUG.
135        (b) In pcre_compile(), rename the member of the "branch_chain" structure
136            called "current" as "current_branch", to prevent a collision with the
137            Linux macro when compiled as a kernel module.
139        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
140            prevent a collision with the Linux macro when compiled as a kernel
141            module.
143    8.  In pcre_compile() there are some checks for integer overflows that used to
144        cast potentially large values to (double). This has been changed to that
145        when building, a check for int64_t is made, and if it is found, it is used
146        instead, thus avoiding the use of floating point arithmetic. (There is no
147        other use of FP in PCRE.) If int64_t is not found, the fallback is to
148        double.
150    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
151        2005 (difference between two addresses compared to an unsigned value).
153    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
154        custom one, because of the following reported problem in Windows:
156          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
157              under Win32.
158          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
159              therefore missing the function definition.
160          - The compiler thus generates a "C" signature for the test function.
161          - The linker fails to find the "C" function.
162          - PCRE fails to configure if asked to do so against libbz2.
164    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
165        messages were output:
167          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
168          rerunning libtoolize, to keep the correct libtool macros in-tree.
169          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
171        I have done both of these things.
173    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
174        most of the time, it *can* run out if it is given a pattern that contains a
175        runaway infinite recursion. I updated the discussion in the pcrestack man
176        page.
178    13. Now that we have gone to the x.xx style of version numbers, the minor
179        version may start with zero. Using 08 or 09 is a bad idea because users
180        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
181        interpreted as invalid octal numbers. I've updated the previous comment in
182        configure.ac, and also added a check that gives an error if 08 or 09 are
183        used.
185    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
186        causing partial matching to fail when the end of the subject matched \W
187        in a UTF-8 pattern where \W was quantified with a minimum of 3.
189    15. There were some discrepancies between the declarations in pcre_internal.h
190        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
191        their definitions. The declarations used "const uschar *" and the
192        definitions used USPTR. Even though USPTR is normally defined as "const
193        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
194        reported that: "This difference in casting confuses some C++ compilers, for
195        example, SunCC recognizes above declarations as different functions and
196        generates broken code for hbpcre." I have changed the declarations to use
197        USPTR.
199    16. GNU libtool is named differently on some systems. The autogen.sh script now
200        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
201        (FreeBSD).
203    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
204        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
205        comment: "Figure out how to create a longlong from a string: strtoll and
206        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
207        instance, but it only takes 2 args instead of 3!"
209    18. A subtle bug concerned with back references has been fixed by a change of
210        specification, with a corresponding code fix. A pattern such as
211        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
212        refers, was giving matches when it shouldn't. For example, xa=xaaa would
213        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
214        same bug. Such groups have to be quantified to be useful, or contained
215        inside another quantified group. (If there's no repetition, the reference
216        can never match.) The problem arises because, having left the group and
217        moved on to the rest of the pattern, a later failure that backtracks into
218        the group uses the captured value from the final iteration of the group
219        rather than the correct earlier one. I have fixed this in PCRE by forcing
220        any group that contains a reference to itself to be an atomic group; that
221        is, there cannot be any backtracking into it once it has completed. This is
222        similar to recursive and subroutine calls.
225    Version 8.00 19-Oct-09
226    ----------------------
228    1.  The table for translating pcre_compile() error codes into POSIX error codes
229        was out-of-date, and there was no check on the pcre_compile() error code
230        being within the table. This could lead to an OK return being given in
231        error.
233    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
234        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
235        in a Windows environment.
237    3.  The pcregrep --count option prints the count for each file even when it is
238        zero, as does GNU grep. However, pcregrep was also printing all files when
239        --files-with-matches was added. Now, when both options are given, it prints
240        counts only for those files that have at least one match. (GNU grep just
241        prints the file name in this circumstance, but including the count seems
242        more useful - otherwise, why use --count?) Also ensured that the
243        combination -clh just lists non-zero counts, with no names.
245    4.  The long form of the pcregrep -F option was incorrectly implemented as
246        --fixed_strings instead of --fixed-strings. This is an incompatible change,
247        but it seems right to fix it, and I didn't think it was worth preserving
248        the old behaviour.
250    5.  The command line items --regex=pattern and --regexp=pattern were not
251        recognized by pcregrep, which required --regex pattern or --regexp pattern
252        (with a space rather than an '='). The man page documented the '=' forms,
253        which are compatible with GNU grep; these now work.
255    6.  No libpcreposix.pc file was created for pkg-config; there was just
256        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
258    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
259        when UCP support is not needed, by modifying the Python script that
260        generates it from Unicode data files. This should not matter if the module
261        is correctly used as a library, but I received one complaint about 50K of
262        unwanted data. My guess is that the person linked everything into his
263        program rather than using a library. Anyway, it does no harm.
265    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
266        was a minimum greater than 1 for a wide character in a possessive
267        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
268        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
269        character. Chaos in the form of incorrect output or a compiling loop could
270        result.
272    9.  The restrictions on what a pattern can contain when partial matching is
273        requested for pcre_exec() have been removed. All patterns can now be
274        partially matched by this function. In addition, if there are at least two
275        slots in the offset vector, the offset of the earliest inspected character
276        for the match and the offset of the end of the subject are set in them when
277        PCRE_ERROR_PARTIAL is returned.
279    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
280        synonymous with PCRE_PARTIAL, for backwards compatibility, and
281        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
282        and may be more useful for multi-segment matching.
284    11. Partial matching with pcre_exec() is now more intuitive. A partial match
285        used to be given if ever the end of the subject was reached; now it is
286        given only if matching could not proceed because another character was
287        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
288        string "Z", which now yields "no match" instead of "partial match". In the
289        case of pcre_dfa_exec(), "no match" is given if every matching path for the
290        final character ended with (*FAIL).
292    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
293        if the pattern had a "must contain" character that was already found in the
294        earlier partial match, unless partial matching was again requested. For
295        example, with the pattern /dog.(body)?/, the "must contain" character is
296        "g". If the first part-match was for the string "dog", restarting with
297        "sbody" failed. This bug has been fixed.
299    13. The string returned by pcre_dfa_exec() after a partial match has been
300        changed so that it starts at the first inspected character rather than the
301        first character of the match. This makes a difference only if the pattern
302        starts with a lookbehind assertion or \b or \B (\K is not supported by
303        pcre_dfa_exec()). It's an incompatible change, but it makes the two
304        matching functions compatible, and I think it's the right thing to do.
306    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
307        so that the demonstration program is easily available in environments where
308        PCRE has not been installed from source.
310    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
311        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
312        library.
314    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
315        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
316        is not the first non-POSIX option to be added. Clearly some people find
317        these options useful.
319    17. If a caller to the POSIX matching function regexec() passes a non-zero
320        value for nmatch with a NULL value for pmatch, the value of
321        nmatch is forced to zero.
323    18. RunGrepTest did not have a test for the availability of the -u option of
324        the diff command, as RunTest does. It now checks in the same way as
325        RunTest, and also checks for the -b option.
327    19. If an odd number of negated classes containing just a single character
328        interposed, within parentheses, between a forward reference to a named
329        subpattern and the definition of the subpattern, compilation crashed with
330        an internal error, complaining that it could not find the referenced
331        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
332        [The bug was that it was starting one character too far in when skipping
333        over the character class, thus treating the ] as data rather than
334        terminating the class. This meant it could skip too much.]
336    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
337        /g option in pcretest when the pattern contains \K, which makes it possible
338        to have an empty string match not at the start, even when the pattern is
339        anchored. Updated pcretest and pcredemo to use this option.
341    21. If the maximum number of capturing subpatterns in a recursion was greater
342        than the maximum at the outer level, the higher number was returned, but
343        with unset values at the outer level. The correct (outer level) value is
344        now given.
346    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
347        PCRE did not set those parentheses (unlike Perl). I have now found a way to
348        make it do so. The string so far is captured, making this feature
349        compatible with Perl.
351    23. The tests have been re-organized, adding tests 11 and 12, to make it
352        possible to check the Perl 5.10 features against Perl 5.10.
354    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
355        pattern matches a fixed length string. PCRE did not allow this; now it
356        does. Neither allows recursion.
358    25. I finally figured out how to implement a request to provide the minimum
359        length of subject string that was needed in order to match a given pattern.
360        (It was back references and recursion that I had previously got hung up
361        on.) This code has now been added to pcre_study(); it finds a lower bound
362        to the length of subject needed. It is not necessarily the greatest lower
363        bound, but using it to avoid searching strings that are too short does give
364        some useful speed-ups. The value is available to calling programs via
365        pcre_fullinfo().
367    26. While implementing 25, I discovered to my embarrassment that pcretest had
368        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
369        study optimizations had never been tested with that matching function.
370        Oops. What is worse, even when it was passed study data, there was a bug in
371        pcre_dfa_exec() that meant it never actually used it. Double oops. There
372        were also very few tests of studied patterns with pcre_dfa_exec().
374    27. If (?| is used to create subpatterns with duplicate numbers, they are now
375        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
376        on the other side of the coin, they are no longer allowed to have different
377        names, because these cannot be distinguished in PCRE, and this has caused
378        confusion. (This is a difference from Perl.)
380    28. When duplicate subpattern names are present (necessarily with different
381        numbers, as required by 27 above), and a test is made by name in a
382        conditional pattern, either for a subpattern having been matched, or for
383        recursion in such a pattern, all the associated numbered subpatterns are
384        tested, and the overall condition is true if the condition is true for any
385        one of them. This is the way Perl works, and is also more like the way
386        testing by number works.
389    Version 7.9 11-Apr-09
390    ---------------------
392    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
393        (pcretest), all targets were linked against these libraries. This included
394        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
395        libraries. This caused unwanted dependencies to be created. This problem
396        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
397        pcretest is linked with readline.
399    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
400        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
401        moved outside it again, because FALSE and TRUE are already defined in AIX,
402        but BOOL is not.
404    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
405        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
407    4.  The pcregrep documentation said spaces were inserted as well as colons (or
408        hyphens) following file names and line numbers when outputting matching
409        lines. This is not true; no spaces are inserted. I have also clarified the
410        wording for the --colour (or --color) option.
412    5.  In pcregrep, when --colour was used with -o, the list of matching strings
413        was not coloured; this is different to GNU grep, so I have changed it to be
414        the same.
416    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
417        each matching line was coloured. Now it goes on to look for further matches
418        of any of the test patterns, which is the same behaviour as GNU grep.
420    7.  A pattern that could match an empty string could cause pcregrep to loop; it
421        doesn't make sense to accept an empty string match in pcregrep, so I have
422        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
423        seems to be how GNU grep behaves.
425    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
426        start or after a newline", because the conditional assertion was not being
427        correctly handled. The rule now is that both the assertion and what follows
428        in the first alternative must satisfy the test.
430    9.  If auto-callout was enabled in a pattern with a conditional group whose
431        condition was an assertion, PCRE could crash during matching, both with
432        pcre_exec() and pcre_dfa_exec().
434    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
435        used for matching.
437    11. Unicode property support in character classes was not working for
438        characters (bytes) greater than 127 when not in UTF-8 mode.
440    12. Added the -M command line option to pcretest.
442    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
444    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
446    16. Added comments and documentation about mis-use of no_arg in the C++
447        wrapper.
449    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
450        from Martin Jerabek that uses macro names for all relevant character and
451        string constants.
453    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
454        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
455        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
456        these, but not everybody uses configure.
458    19. A conditional group that had only one branch was not being correctly
459        recognized as an item that could match an empty string. This meant that an
460        enclosing group might also not be so recognized, causing infinite looping
461        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
462        with the subject "ab", where knowledge that the repeated group can match
463        nothing is needed in order to break the loop.
465    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
466        exec(), but without supplying a callout function, matching went wrong.
468    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
469        leak if the size of the offset vector was greater than 30. When the vector
470        is smaller, the saved offsets during recursion go onto a local stack
471        vector, but for larger vectors malloc() is used. It was failing to free
472        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
473        error, in fact).
475    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
476        heapframe that is used only when UTF-8 support is enabled. This caused no
477        problem, but was untidy.
479    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
480        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
481        included within another project.
483    24. Steven Van Ingelgem's patches to add more options to the CMake support,
484        slightly modified by me:
486          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
487              not building pcregrep.
489          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
490              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
492    25. Forward references, both numeric and by name, in patterns that made use of
493        duplicate group numbers, could behave incorrectly or give incorrect errors,
494        because when scanning forward to find the reference group, PCRE was not
495        taking into account the duplicate group numbers. A pattern such as
496        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
498    26. Changed a few more instances of "const unsigned char *" to USPTR, making
499        the feature of a custom pointer more persuasive (as requested by a user).
501    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
502        pcretest.c, inside #ifndefs, because it seems they are sometimes already
503        pre-defined.
505    28. Added support for (*UTF8) at the start of a pattern.
507    29. Arrange for flags added by the "release type" setting in CMake to be shown
508        in the configuration summary.
511    Version 7.8 05-Sep-08
512    ---------------------
514    1.  Replaced UCP searching code with optimized version as implemented for Ad
515        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
516        stage table and inline lookup instead of a function, giving speed ups of 2
517        to 5 times on some simple patterns that I tested. Permission was given to
518        distribute the MultiStage2.py script that generates the tables (it's not in
519        the tarball, but is in the Subversion repository).
521    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
522        scripts.
524    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
525        a group with a zero qualifier. The result of the study could be incorrect,
526        or the function might crash, depending on the pattern.
528    4.  Caseless matching was not working for non-ASCII characters in back
529        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
530        It now works when Unicode Property Support is available.
532    5.  In pcretest, an escape such as \x{de} in the data was always generating
533        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
534        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
535        truncation.
537    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
539    7.  Added two (int) casts to pcregrep when printing the difference of two
540        pointers, in case they are 64-bit values.
542    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
543        test 2 if it fails.
545    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
546        and a #define of that name to empty if it is not externally set. This is to
547        allow users of MSVC to set it if necessary.
549    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
550        the convenience functions in the pcre_get.c source file.
552    11. An option change at the start of a pattern that had top-level alternatives
553        could cause overwriting and/or a crash. This command provoked a crash in
554        some environments:
556          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
558        This potential security problem was recorded as CVE-2008-2371.
560    12. For a pattern where the match had to start at the beginning or immediately
561        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
562        pcre_dfa_exec() could read past the end of the passed subject if there was
563        no match. To help with detecting such bugs (e.g. with valgrind), I modified
564        pcretest so that it places the subject at the end of its malloc-ed buffer.
566    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
567        exec() might read past the end of the data buffer in UTF-8 mode.
569    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
570        the data contained the byte 0x85 as part of a UTF-8 character within its
571        first line. This applied both to normal and DFA matching.
573    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
574        /^[^d]*?$/8 failed to match "abc".
576    16. Added a missing copyright notice to pcrecpp_internal.h.
578    17. Make it more clear in the documentation that values returned from
579        pcre_exec() in ovector are byte offsets, not character counts.
581    18. Tidied a few places to stop certain compilers from issuing warnings.
583    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
584        supplied by Stefan Weber. I made a further small update for 7.8 because
585        there is a change of source arrangements: the pcre_searchfuncs.c module is
586        replaced by pcre_ucd.c.
589    Version 7.7 07-May-08
590    ---------------------
592    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
593        a string to a long long, pretend we don't even have a long long." This is
594        done by checking for the strtoq, strtoll, and _strtoi64 functions.
596    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
597        pre-7.6 versions, which defined a global no_arg variable instead of putting
598        it in the RE class. (See also #8 below.)
600    3.  Remove a line of dead code, identified by coverity and reported by Nuno
601        Lopes.
603    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
605        (1) The include/exclude patterns were being applied to the whole pathnames
606            of files, instead of just to the final components.
608        (2) If there was more than one level of directory, the subdirectories were
609            skipped unless they satisfied the include/exclude conditions. This is
610            inconsistent with GNU grep (and could even be seen as contrary to the
611            pcregrep specification - which I improved to make it absolutely clear).
612            The action now is always to scan all levels of directory, and just
613            apply the include/exclude patterns to regular files.
615    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
616        --exclude_dir in the tests to avoid scanning .svn directories.
618    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
619        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
620        doesn't support NULs in patterns.
622    7.  Added some missing "const"s to declarations of static tables in
623        pcre_compile.c and pcre_dfa_exec.c.
625    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
626        caused by fix #2  above. (Subsequently also a second patch to fix the
627        first patch. And a third patch - this was a messy problem.)
629    9.  Applied Craig's patch to remove the use of push_back().
631    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
632        matching function regexec().
634    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
635        which, however, unlike Perl's \g{...}, are subroutine calls, not back
636        references. PCRE supports relative numbers with this syntax (I don't think
637        Oniguruma does).
639    12. Previously, a group with a zero repeat such as (...){0} was completely
640        omitted from the compiled regex. However, this means that if the group
641        was called as a subroutine from elsewhere in the pattern, things went wrong
642        (an internal error was given). Such groups are now left in the compiled
643        pattern, with a new opcode that causes them to be skipped at execution
644        time.
646    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
647        to the way PCRE behaves:
649        (a) A lone ] character is dis-allowed (Perl treats it as data).
651        (b) A back reference to an unmatched subpattern matches an empty string
652            (Perl fails the current match path).
654        (c) A data ] in a character class must be notated as \] because if the
655            first data character in a class is ], it defines an empty class. (In
656            Perl it is not possible to have an empty class.) The empty class []
657            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
658            The negative empty class [^] matches any one character, independently
659            of the DOTALL setting.
661    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
662        non-existent subpattern following a character class starting with ']' and
663        containing () gave an internal compiling error instead of "reference to
664        non-existent subpattern". Fortunately, when the pattern did exist, the
665        compiled code was correct. (When scanning forwards to check for the
666        existencd of the subpattern, it was treating the data ']' as terminating
667        the class, so got the count wrong. When actually compiling, the reference
668        was subsequently set up correctly.)
670    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
671        it was being rejected as not supported by pcre_dfa_exec(), even though
672        other assertions are supported. I have made pcre_dfa_exec() support
673        (*FAIL).
675    16. The implementation of 13c above involved the invention of a new opcode,
676        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
677        cannot be changed at match time, I realized I could make a small
678        improvement to matching performance by compiling OP_ALLANY instead of
679        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
680        on the OP_ANY path.
682    17. Compiling pcretest on Windows with readline support failed without the
683        following two fixes: (1) Make the unistd.h include conditional on
684        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
686    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
687        ncurses library to be included for pcretest when ReadLine support is
688        requested, but also to allow for it to be overridden. This patch came from
689        Daniel Bergström.
691    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
692        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
693        any errors with the current Unicode tables. Thanks to Peter Kankowski for
694        spotting this.
697    Version 7.6 28-Jan-08
698    ---------------------
700    1.  A character class containing a very large number of characters with
701        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
702        overflow.
704    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
705        HAVE_LONG_LONG is not defined.
707    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
708        bring them up to date and include new features. This patch includes:
710        - Fixed PH's badly added libz and libbz2 support.
711        - Fixed a problem with static linking.
712        - Added pcredemo. [But later removed - see 7 below.]
713        - Fixed dftables problem and added an option.
714        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
715            HAVE_LONG_LONG.
716        - Added readline support for pcretest.
717        - Added an listing of the option settings after cmake has run.
719    4.  A user submitted a patch to Makefile that makes it easy to create
720        "pcre.dll" under mingw when using Configure/Make. I added stuff to
721        Makefile.am that cause it to include this special target, without
722        affecting anything else. Note that the same mingw target plus all
723        the other distribution libraries and programs are now supported
724        when configuring with CMake (see 6 below) instead of with
725        Configure/Make.
727    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
728        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
729        exported in the Windows port". It has not yet been confirmed that the patch
730        solves the problem, but it does no harm.
732    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
733        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
734        with CMake, and also correct the comment about stack recursion.
736    7.  Remove the automatic building of pcredemo from the ./configure system and
737        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
738        of a program that users should build themselves after PCRE is installed, so
739        building it automatically is not really right. What is more, it gave
740        trouble in some build environments.
742    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
745    Version 7.5 10-Jan-08
746    ---------------------
748    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
749        values in parens when parsing an RE using the C++ wrapper."
751    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
752        Characters greater than 255 were excluded from the class instead of being
753        included.
755    3.  The same bug as (2) above applied to negated POSIX classes such as
756        [:^space:].
758    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
759        defined or documented. It seems to have been a typo for PCRE_STATIC, so
760        I have changed it.
762    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
763        first named subpattern) and a construct such as (?&a) would reference the
764        first named subpattern whose name started with "a" (in other words, the
765        length check was missing). Both these problems are fixed. "Subpattern name
766        expected" is now given for (?&) (a zero-length name), and this patch also
767        makes it give the same error for \k'' (previously it complained that that
768        was a reference to a non-existent subpattern).
770    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
771        this is right because (?- can be followed by option settings as well as by
772        digits. I have, however, made the messages clearer.
774    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
775        than the number used in the conditional) now cause a compile-time error.
776        This is actually not compatible with Perl, which accepts such patterns, but
777        treats the conditional as always being FALSE (as PCRE used to), but it
778        seems to me that giving a diagnostic is better.
780    8.  Change "alphameric" to the more common word "alphanumeric" in comments
781        and messages.
783    9.  Fix two occurrences of "backslash" in comments that should have been
784        "backspace".
786    10. Remove two redundant lines of code that can never be obeyed (their function
787        was moved elsewhere).
789    11. The program that makes PCRE's Unicode character property table had a bug
790        which caused it to generate incorrect table entries for sequences of
791        characters that have the same character type, but are in different scripts.
792        It amalgamated them into a single range, with the script of the first of
793        them. In other words, some characters were in the wrong script. There were
794        thirteen such cases, affecting characters in the following ranges:
796          U+002b0 - U+002c1
797          U+0060c - U+0060d
798          U+0061e - U+00612
799          U+0064b - U+0065e
800          U+0074d - U+0076d
801          U+01800 - U+01805
802          U+01d00 - U+01d77
803          U+01d9b - U+01dbf
804          U+0200b - U+0200f
805          U+030fc - U+030fe
806          U+03260 - U+0327f
807          U+0fb46 - U+0fbb1
808          U+10450 - U+1049d
810    12. The -o option (show only the matching part of a line) for pcregrep was not
811        compatible with GNU grep in that, if there was more than one match in a
812        line, it showed only the first of them. It now behaves in the same way as
813        GNU grep.
815    13. If the -o and -v options were combined for pcregrep, it printed a blank
816        line for every non-matching line. GNU grep prints nothing, and pcregrep now
817        does the same. The return code can be used to tell if there were any
818        non-matching lines.
820    14. Added --file-offsets and --line-offsets to pcregrep.
822    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
823        infinitely looping recursion. The bug was that positive lookaheads were not
824        being skipped when checking for a possible empty match (negative lookaheads
825        and both kinds of lookbehind were skipped).
827    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
828        inclusion of <windows.h> to before rather than after the definition of
829        INVALID_FILE_ATTRIBUTES (patch from David Byron).
831    17. Specifying a possessive quantifier with a specific limit for a Unicode
832        character property caused pcre_compile() to compile bad code, which led at
833        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
834        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
835        caused the error; without that there was no problem.
837    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
839    19. Added --enable-pcretest-libreadline.
841    20. In pcrecpp.cc, the variable 'count' was incremented twice in
842        RE::GlobalReplace(). As a result, the number of replacements returned was
843        double what it should be. I removed one of the increments, but Craig sent a
844        later patch that removed the other one (the right fix) and added unit tests
845        that check the return values (which was not done before).
847    21. Several CMake things:
849        (1) Arranged that, when cmake is used on Unix, the libraries end up with
850            the names libpcre and libpcreposix, not just pcre and pcreposix.
852        (2) The above change means that pcretest and pcregrep are now correctly
853            linked with the newly-built libraries, not previously installed ones.
857    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
858        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
859        UTF-8 newline character). The key issue is that the pattern starts .*;
860        this means that the match must be either at the beginning, or after a
861        newline. The bug was in the code for advancing after a failed match and
862        checking that the new position followed a newline. It was not taking
863        account of UTF-8 characters correctly.
865    23. PCRE was behaving differently from Perl in the way it recognized POSIX
866        character classes. PCRE was not treating the sequence [:...:] as a
867        character class unless the ... were all letters. Perl, however, seems to
868        allow any characters between [: and :], though of course it rejects as
869        unknown any "names" that contain non-letters, because all the known class
870        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
871        for example, whereas PCRE did not - it did not recognize a POSIX character
872        class. This seemed a bit dangerous, so the code has been changed to be
873        closer to Perl. The behaviour is not identical to Perl, because PCRE will
874        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
875        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
876        Perl does, and where it didn't before.
878    24. Rewrite so as to remove the single use of %n from pcregrep because in some
879        Windows environments %n is disabled by default.
882    Version 7.4 21-Sep-07
883    ---------------------
885    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
886        means that a class such as [\s] counted as "explicit reference to CR or
887        LF". That isn't really right - the whole point of the change was to try to
888        help when there was an actual mention of one of the two characters. So now
889        the change happens only if \r or \n (or a literal CR or LF) character is
890        encountered.
892    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
893        of both had grown to the point where there were only 3 bits left.
894        Fortunately, there was spare space in the data structure, and so I have
895        moved the internal flags into a new 16-bit field to free up more option
896        bits.
898    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
899        but did not set the internal JCHANGED flag - either of these is enough to
900        control the way the "get" function works - but the PCRE_INFO_JCHANGED
901        facility is supposed to tell if (?J) was ever used, so now (?J) at the
902        start sets both bits.
904    4.  Added options (at build time, compile time, exec time) to change \R from
905        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
907    5.  doc/pcresyntax.html was missing from the distribution.
909    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
910        compatibility, even though it is no longer used.
912    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
913        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
914        windows.h file is present (where different names are used). [This was
915        reversed later after testing - see 16 below.]
917    8.  Changed all #include <config.h> to #include "config.h". There were also
918        some further <pcre.h> cases that I changed to "pcre.h".
920    9.  When pcregrep was used with the --colour option, it missed the line ending
921        sequence off the lines that it output.
923    10. It was pointed out to me that arrays of string pointers cause lots of
924        relocations when a shared library is dynamically loaded. A technique of
925        using a single long string with a table of offsets can drastically reduce
926        these. I have refactored PCRE in four places to do this. The result is
927        dramatic:
929          Originally:                          290
930          After changing UCP table:            187
931          After changing error message table:   43
932          After changing table of "verbs"       36
933          After changing table of Posix names   22
935        Thanks to the folks working on Gregex for glib for this insight.
937    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
938        unicode-properties was also set.
940    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
942    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
943        checked only for CRLF.
945    14. Added casts to pcretest.c to avoid compiler warnings.
947    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
949    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
950        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
951        entirely. This removes changes made in 7 above.
953    17. The CMake files have been updated, and there is now more information about
954        building with CMake in the NON-UNIX-USE document.
957    Version 7.3 28-Aug-07
958    ---------------------
960     1. In the rejigging of the build system that eventually resulted in 7.1, the
961        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
962        brackets there is not right, since it causes compilers to look for an
963        installed pcre.h, not the version that is in the source that is being
964        compiled (which of course may be different). I have changed it back to:
966          #include "pcre.h"
968        I have a vague recollection that the change was concerned with compiling in
969        different directories, but in the new build system, that is taken care of
970        by the VPATH setting the Makefile.
972     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
973        when the subject happened to end in the byte 0x85 (e.g. if the last
974        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
975        characters but of course it shouldn't be taken as a newline when it is part
976        of another character. The bug was that, for an unlimited repeat of . in
977        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
978        characters when looking for a newline.
980     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
982     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
983        in debug output.
985     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
986        long printing in the pcrecpp unittest when running under MinGW.
988     6. ESC_K was left out of the EBCDIC table.
990     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
991        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
992        limit also applies to "virtual nesting" when a pattern is recursive, and in
993        this case 1000 isn't so big. I have been able to remove this limit at the
994        expense of backing off one optimization in certain circumstances. Normally,
995        when pcre_exec() would call its internal match() function recursively and
996        immediately return the result unconditionally, it uses a "tail recursion"
997        feature to save stack. However, when a subpattern that can match an empty
998        string has an unlimited repetition quantifier, it no longer makes this
999        optimization. That gives it a stack frame in which to save the data for
1000        checking that an empty string has been matched. Previously this was taken
1001        from the 1000-entry workspace that had been reserved. So now there is no
1002        explicit limit, but more stack is used.
1004     8. Applied Daniel's patches to solve problems with the import/export magic
1005        syntax that is required for Windows, and which was going wrong for the
1006        pcreposix and pcrecpp parts of the library. These were overlooked when this
1007        problem was solved for the main library.
1009     9. There were some crude static tests to avoid integer overflow when computing
1010        the size of patterns that contain repeated groups with explicit upper
1011        limits. As the maximum quantifier is 65535, the maximum group length was
1012        set at 30,000 so that the product of these two numbers did not overflow a
1013        32-bit integer. However, it turns out that people want to use groups that
1014        are longer than 30,000 bytes (though not repeat them that many times).
1015        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1016        made it possible to implement the integer overflow checks in a much more
1017        dynamic way, which I have now done. The artificial limitation on group
1018        length has been removed - we now have only the limit on the total length of
1019        the compiled pattern, which depends on the LINK_SIZE setting.
1021    10. Fixed a bug in the documentation for get/copy named substring when
1022        duplicate names are permitted. If none of the named substrings are set, the
1023        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1024        empty string.
1026    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1027        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1028        because the ] is interpreted as the first data character and the
1029        terminating ] is not found. PCRE has been made compatible with Perl in this
1030        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1031        cause memory overwriting.
1033    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1034        string has been matched (to stop an infinite loop). It was not recognizing
1035        a conditional subpattern that could match an empty string if that
1036        subpattern was within another subpattern. For example, it looped when
1037        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1038        condition was not nested. This bug has been fixed.
1040    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1041        past the start of the subject in the presence of bytes with the top bit
1042        set, for example "\x8aBCD".
1044    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1045        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1047    14. Optimized (?!) to (*FAIL).
1049    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1050        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1051        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1052        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1053        does: it's just the validity check that is more restrictive.
1055    16. Inserted checks for integer overflows during escape sequence (backslash)
1056        processing, and also fixed erroneous offset values for syntax errors during
1057        backslash processing.
1059    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1060        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1062    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1063        caused an overrun.
1065    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1066        something other than just ASCII characters) inside a group that had an
1067        unlimited repeat caused a loop at compile time (while checking to see
1068        whether the group could match an empty string).
1070    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1071        [\P{Any}] did so. (Error in the code for printing property names.)
1073    21. An orphan \E inside a character class could cause a crash.
1075    22. A repeated capturing bracket such as (A)? could cause a wild memory
1076        reference during compilation.
1078    23. There are several functions in pcre_compile() that scan along a compiled
1079        expression for various reasons (e.g. to see if it's fixed length for look
1080        behind). There were bugs in these functions when a repeated \p or \P was
1081        present in the pattern. These operators have additional parameters compared
1082        with \d, etc, and these were not being taken into account when moving along
1083        the compiled data. Specifically:
1085        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1086            length.
1088        (b) An item such as \pL+ within a repeated group could cause crashes or
1089            loops.
1091        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1092            "reference to non-existent subpattern" error.
1094        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1096    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1097        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1099    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1101    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1102        character were causing crashes (broken optimization).
1104    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1105        \p or \P) caused a compile-time loop.
1107    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1108        break. For example, the unstudied pattern [\r\n]A does not match the string
1109        "\r\nA" because change 7.0/46 below moves the current point on by two
1110        characters after failing to match at the start. However, the pattern \nA
1111        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1112        the same is true. There doesn't seem any very clean way out of this, but
1113        what I have chosen to do makes the common cases work: PCRE now takes note
1114        of whether there can be an explicit match for \r or \n anywhere in the
1115        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1116        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1117        pattern has explicit CR or LF references.
1119    29. Added (*CR) etc for changing newline setting at start of pattern.
1122    Version 7.2 19-Jun-07
1123    ---------------------
1125     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1126        which is apparently normally available under Windows.
1128     2. Re-jig the pcregrep tests with different newline settings in an attempt
1129        to make them independent of the local environment's newline setting.
1131     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1133     4. Some of the "internals" tests were previously cut out when the link size
1134        was not 2, because the output contained actual offsets. The recent new
1135        "Z" feature of pcretest means that these can be cut out, making the tests
1136        usable with all link sizes.
1138     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1139        stack recursion. This gives a massive performance boost under BSD, but just
1140        a small improvement under Linux. However, it saves one field in the frame
1141        in all cases.
1143     6. Added more features from the forthcoming Perl 5.10:
1145        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1146            recursion call. It refers to the nth most recently opened parentheses.
1148        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1149            to be opened parentheses.
1151        (c) Conditions that refer to capturing parentheses can be specified
1152            relatively, for example, (?(-2)... or (?(+3)...
1154        (d) \K resets the start of the current match so that everything before
1155            is not part of it.
1157        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1159        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1160            reference syntax.
1162        (g) (?| introduces a group in which the numbering of parentheses in each
1163            alternative starts with the same number.
1165        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1167     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1170     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1171        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1172        for detecting groups that can match an empty string.
1174     9. A pattern with a very large number of alternatives (more than several
1175        hundred) was running out of internal workspace during the pre-compile
1176        phase, where pcre_compile() figures out how much memory will be needed. A
1177        bit of new cunning has reduced the workspace needed for groups with
1178        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1179        workspace instead of running out of the 4096 that are available.
1181    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1183    11. Applied patch from Google to remove an optimization that didn't quite work.
1184        The report of the bug said:
1186          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1187          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1188          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1190    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1191        it matched the wrong number of bytes.
1194    Version 7.1 24-Apr-07
1195    ---------------------
1197     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1198        that is more "standard", making use of automake and other Autotools. There
1199        is some re-arrangement of the files and adjustment of comments consequent
1200        on this.
1202     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1203        for recursive directory scanning broke on some systems because the files
1204        are not scanned in any specific order and on different systems the order
1205        was different. A call to "sort" has been inserted into RunGrepTest for the
1206        approprate test as a short-term fix. In the longer term there may be an
1207        alternative.
1209     3. I had an email from Eric Raymond about problems translating some of PCRE's
1210        man pages to HTML (despite the fact that I distribute HTML pages, some
1211        people do their own conversions for various reasons). The problems
1212        concerned the use of low-level troff macros .br and .in. I have therefore
1213        removed all such uses from the man pages (some were redundant, some could
1214        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1215        HTML has been updated to handle .nf/.fi and to complain if it encounters
1216        .br or .in.
1218     4. Updated comments in configure.ac that get placed in config.h.in and also
1219        arranged for config.h to be included in the distribution, with the name
1220        config.h.generic, for the benefit of those who have to compile without
1221        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1223     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1224        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1225        makevp.bat for the current PCRE, using the additional files
1226        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1228     6. A Windows user reported a minor discrepancy with test 2, which turned out
1229        to be caused by a trailing space on an input line that had got lost in his
1230        copy. The trailing space was an accident, so I've just removed it.
1232     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1233        that is needed.
1235     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1236        as "const" (a) because they are and (b) because it helps the PHP
1237        maintainers who have recently made a script to detect big data structures
1238        in the php code that should be moved to the .rodata section. I remembered
1239        to update Builducptable as well, so it won't revert if ucptable.h is ever
1240        re-created.
1242     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1243        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1244        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1245        support is not required. This saves 1.5-2K of code, which is important in
1246        some applications.
1248        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1249        so as not to refer to the tables, even though these functions will never be
1250        called when UTF-8 support is disabled. Otherwise there are problems with a
1251        shared library.
1253    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1255        (a) It was defining its arguments as char * instead of void *.
1257        (b) It was assuming that all moves were upwards in memory; this was true
1258            a long time ago when I wrote it, but is no longer the case.
1260        The emulated memove() is provided for those environments that have neither
1261        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1262        is clearly not the case, as these two bugs were recently reported.
1264    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1265        and Detrail to create the HTML documentation, the .txt form of the man
1266        pages, and it removes trailing spaces from listed files. It also creates
1267        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1268        case, it wraps all the #defines with #ifndefs. This script should be run
1269        before "make dist".
1271    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1272        with Unicode property support.
1274        (a) For a maximizing quantifier, if the two different cases of the
1275            character were of different lengths in their UTF-8 codings (there are
1276            some cases like this - I found 11), and the matching function had to
1277            back up over a mixture of the two cases, it incorrectly assumed they
1278            were both the same length.
1280        (b) When PCRE was configured to use the heap rather than the stack for
1281            recursion during matching, it was not correctly preserving the data for
1282            the other case of a UTF-8 character when checking ahead for a match
1283            while processing a minimizing repeat. If the check also involved
1284            matching a wide character, but failed, corruption could cause an
1285            erroneous result when trying to check for a repeat of the original
1286            character.
1288    13. Some tidying changes to the testing mechanism:
1290        (a) The RunTest script now detects the internal link size and whether there
1291            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1292            values substituted by "configure". (The RunGrepTest script already did
1293            this for UTF-8.) The configure.ac script no longer substitutes the
1294            relevant variables.
1296        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1297            with length and offset values. This means that the output is different
1298            for different internal link sizes. Test 2 is skipped for link sizes
1299            other than 2 because of this, bypassing the problem. Unfortunately,
1300            there was also a test in test 3 (the locale tests) that used /B and
1301            failed for link sizes other than 2. Rather than cut the whole test out,
1302            I have added a new /Z option to pcretest that replaces the length and
1303            offset values with spaces. This is now used to make test 3 independent
1304            of link size. (Test 2 will be tidied up later.)
1306    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1307        segmentation fault instead of returning the appropriate error message.
1309    15. In multiline mode when the newline sequence was set to "any", the pattern
1310        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1311        This doesn't seem right; it now treats the CRLF combination as the line
1312        ending, and so does not match in that case. It's only a pattern such as ^$
1313        that would hit this one: something like ^ABC$ would have failed after \r
1314        and then tried again after \r\n.
1316    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1317        in an attempt to make files that differ only in their line terminators
1318        compare equal. This works on Linux.
1320    17. Under certain error circumstances pcregrep might try to free random memory
1321        as it exited. This is now fixed, thanks to valgrind.
1323    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1324        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1325        was because its rules for how to advance for /g after matching an empty
1326        string at the end of a line did not allow for this case. They now check for
1327        it specially.
1329    20. pcretest is supposed to handle patterns and data of any length, by
1330        extending its buffers when necessary. It was getting this wrong when the
1331        buffer for a data line had to be extended.
1333    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1334        CRLF as a newline sequence.
1336    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1337        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1338        I have nevertheless tidied it up.
1340    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1342    24. Added a man page for pcre-config.
1345    Version 7.0 19-Dec-06
1346    ---------------------
1348     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1349        moving to gcc 4.1.1.
1351     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1352        sys/time.h, which is documented as needed for this function. It doesn't
1353        seem to matter on Linux, but it showed up on some releases of OS X.
1355     3. It seems that there are systems where bytes whose values are greater than
1356        127 match isprint() in the "C" locale. The "C" locale should be the
1357        default when a C program starts up. In most systems, only ASCII printing
1358        characters match isprint(). This difference caused the output from pcretest
1359        to vary, making some of the tests fail. I have changed pcretest so that:
1361        (a) When it is outputting text in the compiled version of a pattern, bytes
1362            other than 32-126 are always shown as hex escapes.
1364        (b) When it is outputting text that is a matched part of a subject string,
1365            it does the same, unless a different locale has been set for the match
1366            (using the /L modifier). In this case, it uses isprint() to decide.
1368     4. Fixed a major bug that caused incorrect computation of the amount of memory
1369        required for a compiled pattern when options that changed within the
1370        pattern affected the logic of the preliminary scan that determines the
1371        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1372        that the computed length was too small. The symptoms of this bug were
1373        either the PCRE error "internal error: code overflow" from pcre_compile(),
1374        or a glibc crash with a message such as "pcretest: free(): invalid next
1375        size (fast)". Examples of patterns that provoked this bug (shown in
1376        pcretest format) are:
1378          /(?-x: )/x
1379          /(?x)(?-x: \s*#\s*)/
1380          /((?i)[\x{c0}])/8
1381          /(?i:[\x{c0}])/8
1383        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1384        is now done differently.
1386     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1387        wrapper classes; (b) implement a new function in the C++ scanner that is
1388        more efficient than the old way of doing things because it avoids levels of
1389        recursion in the regex matching; (c) add a paragraph to the documentation
1390        for the FullMatch() function.
1392     6. The escape sequence \n was being treated as whatever was defined as
1393        "newline". Not only was this contrary to the documentation, which states
1394        that \n is character 10 (hex 0A), but it also went horribly wrong when
1395        "newline" was defined as CRLF. This has been fixed.
1397     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1398        was being set to -1 for the "end of line" case (supposedly a value that no
1399        character can have). Though this value is never used (the check for end of
1400        line is "zero bytes in current character"), it caused compiler complaints.
1401        I've changed it to 0xffffffff.
1403     8. In pcre_version.c, the version string was being built by a sequence of
1404        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1405        string (as it is for production releases) called a macro with an empty
1406        argument. The C standard says the result of this is undefined. The gcc
1407        compiler treats it as an empty string (which was what was wanted) but it is
1408        reported that Visual C gives an error. The source has been hacked around to
1409        avoid this problem.
1411     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1412        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1413        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1414        of them did).
1416    10. Originally, pcretest opened its input and output without "b"; then I was
1417        told that "b" was needed in some environments, so it was added for release
1418        5.0 to both the input and output. (It makes no difference on Unix-like
1419        systems.) Later I was told that it is wrong for the input on Windows. I've
1420        now abstracted the modes into two macros, to make it easier to fiddle with
1421        them, and removed "b" from the input mode under Windows.
1423    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1425    12. Added -help and --help to pcretest as an official way of being reminded
1426        of the options.
1428    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1429        and pcrecpp.cc because they annoy compilers at high warning levels.
1431    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1433    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1434        scripts are not C programs :-) and which was not noticed because it works
1435        on Linux.
1437    16. pcretest is supposed to handle any length of pattern and data line (as one
1438        line or as a continued sequence of lines) by extending its input buffer if
1439        necessary. This feature was broken for very long pattern lines, leading to
1440        a string of junk being passed to pcre_compile() if the pattern was longer
1441        than about 50K.
1443    17. I have done a major re-factoring of the way pcre_compile() computes the
1444        amount of memory needed for a compiled pattern. Previously, there was code
1445        that made a preliminary scan of the pattern in order to do this. That was
1446        OK when PCRE was new, but as the facilities have expanded, it has become
1447        harder and harder to keep it in step with the real compile phase, and there
1448        have been a number of bugs (see for example, 4 above). I have now found a
1449        cunning way of running the real compile function in a "fake" mode that
1450        enables it to compute how much memory it would need, while actually only
1451        ever using a few hundred bytes of working memory and without too many
1452        tests of the mode. This should make future maintenance and development
1453        easier. A side effect of this work is that the limit of 200 on the nesting
1454        depth of parentheses has been removed (though this was never a serious
1455        limitation, I suspect). However, there is a downside: pcre_compile() now
1456        runs more slowly than before (30% or more, depending on the pattern). I
1457        hope this isn't a big issue. There is no effect on runtime performance.
1459    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1460        newline (only possible for the last line of a file) and it was a
1461        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1463    19. Added additional timing features to pcretest. (1) The -tm option now times
1464        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1465        separate command line item, by a number that specifies the number of
1466        repeats to use when timing. The default is 50000; this gives better
1467        precision, but takes uncomfortably long for very large patterns.
1469    20. Extended pcre_study() to be more clever in cases where a branch of a
1470        subpattern has no definite first character. For example, (a*|b*)[cd] would
1471        previously give no result from pcre_study(). Now it recognizes that the
1472        first character must be a, b, c, or d.
1474    21. There was an incorrect error "recursive call could loop indefinitely" if
1475        a subpattern (or the entire pattern) that was being tested for matching an
1476        empty string contained only one non-empty item after a nested subpattern.
1477        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1478        incorrectly, because the \d was being skipped in the check.
1480    22. The pcretest program now has a new pattern option /B and a command line
1481        option -b, which is equivalent to adding /B to every pattern. This causes
1482        it to show the compiled bytecode, without the additional information that
1483        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1484        is the same as /B/I).
1486    23. A new optimization is now able automatically to treat some sequences such
1487        as a*b as a*+b. More specifically, if something simple (such as a character
1488        or a simple class like \d) has an unlimited quantifier, and is followed by
1489        something that cannot possibly match the quantified thing, the quantifier
1490        is automatically "possessified".
1492    24. A recursive reference to a subpattern whose number was greater than 39
1493        went wrong under certain circumstances in UTF-8 mode. This bug could also
1494        have affected the operation of pcre_study().
1496    25. Realized that a little bit of performance could be had by replacing
1497        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1499    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1501    27. Possessive quantifiers such as a++ were previously implemented by turning
1502        them into atomic groups such as ($>a+). Now they have their own opcodes,
1503        which improves performance. This includes the automatically created ones
1504        from 23 above.
1506    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1507        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1508        the first matched character to be a colon. This applied both to named and
1509        numbered groups.
1511    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1513    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1514        building PCRE on Windows easier, so I have included it in the distribution.
1516    31. There is now a check in pcretest against a ridiculously large number being
1517        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1518        loop, the loop is abandoned.
1520    32. Forward references to subpatterns in conditions such as (?(2)...) where
1521        subpattern 2 is defined later cause pcre_compile() to search forwards in
1522        the pattern for the relevant set of parentheses. This search went wrong
1523        when there were unescaped parentheses in a character class, parentheses
1524        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1526    33. "Subroutine" calls and backreferences were previously restricted to
1527        referencing subpatterns earlier in the regex. This restriction has now
1528        been removed.
1530    34. Added a number of extra features that are going to be in Perl 5.10. On the
1531        whole, these are just syntactic alternatives for features that PCRE had
1532        previously implemented using the Python syntax or my own invention. The
1533        other formats are all retained for compatibility.
1535        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1536            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1537            also .NET compatible.
1539        (b) A recursion or subroutine call to a named group can now be defined as
1540            (?&name) as well as (?P>name).
1542        (c) A backreference to a named group can now be defined as \k<name> or
1543            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1544            5.10, are also .NET compatible.
1546        (d) A conditional reference to a named group can now use the syntax
1547            (?(<name>) or (?('name') as well as (?(name).
1549        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1550            groups (named and numbered) that are never evaluated inline, but can be
1551            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1552            is always false. There may be only one alternative in such a group.
1554        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1555            as the simple (?(R). The condition is true only if the most recent
1556            recursion is that of the given number or name. It does not search out
1557            through the entire recursion stack.
1559        (g) The escape \gN or \g{N} has been added, where N is a positive or
1560            negative number, specifying an absolute or relative reference.
1562    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1563        some "unreachable code" warnings.
1565    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1566        things, this adds five new scripts.
1568    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1569        There were also incompatibilities regarding the handling of \Q..\E inside
1570        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1571        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1573    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1574        matches an empty string, and forcibly breaks the loop. There were bugs in
1575        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1576        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1577        separate and independent bugs (that affected different cases) have been
1578        fixed.
1580    39. Refactored the code to abolish the use of different opcodes for small
1581        capturing bracket numbers. This is a tidy that I avoided doing when I
1582        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1583        The new approach is not only tidier, it makes it possible to reduce the
1584        memory needed to fix the previous bug (38).
1586    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1587        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1588        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1589        mode.
1591    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1592        report.
1594    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1595        copy construction and assignment in the C++ wrapper.
1597    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1598        couple of bugs that could have given wrong results in the "--newline=crlf"
1599        case.
1601    44. Added a number of casts and did some reorganization of signed/unsigned int
1602        variables following suggestions from Dair Grant. Also renamed the variable
1603        "this" as "item" because it is a C++ keyword.
1605    45. Arranged for dftables to add
1607          #include "pcre_internal.h"
1609        to pcre_chartables.c because without it, gcc 4.x may remove the array
1610        definition from the final binary if PCRE is built into a static library and
1611        dead code stripping is activated.
1613    46. For an unanchored pattern, if a match attempt fails at the start of a
1614        newline sequence, and the newline setting is CRLF or ANY, and the next two
1615        characters are CRLF, advance by two characters instead of one.
1618    Version 6.7 04-Jul-06
1619    ---------------------
1621     1. In order to handle tests when input lines are enormously long, pcretest has
1622        been re-factored so that it automatically extends its buffers when
1623        necessary. The code is crude, but this _is_ just a test program. The
1624        default size has been increased from 32K to 50K.
1626     2. The code in pcre_study() was using the value of the re argument before
1627        testing it for NULL. (Of course, in any sensible call of the function, it
1628        won't be NULL.)
1630     3. The memmove() emulation function in pcre_internal.h, which is used on
1631        systems that lack both memmove() and bcopy() - that is, hardly ever -
1632        was missing a "static" storage class specifier.
1634     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1635        containing an extended class (one that cannot be represented by a bitmap
1636        because it contains high-valued characters or Unicode property items, e.g.
1637        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1638        pattern, but PCRE should not loop if you do not (it no longer does).
1639        [Detail: two cases were found: (a) a repeated subpattern containing an
1640        extended class; (b) a recursive reference to a subpattern that followed a
1641        previous extended class. It wasn't skipping over the extended class
1642        correctly when UTF-8 mode was not set.]
1644     5. A negated single-character class was not being recognized as fixed-length
1645        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1646        compile error "lookbehind assertion is not fixed length".
1648     6. The RunPerlTest auxiliary script was showing an unexpected difference
1649        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1650        write a Perl script that can interpret lines of an input file either as
1651        byte characters or as UTF-8, which is what "perltest" was being required to
1652        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1653        can't do is switch easily at run time between having the "use utf8;" pragma
1654        or not. In the end, I fudged it by using the RunPerlTest script to insert
1655        "use utf8;" explicitly for the UTF-8 tests.
1657     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1658        the end of the subject string, contrary to the documentation and to what
1659        Perl does. This was true of both matching functions. Now it matches only at
1660        the start of the subject and immediately after *internal* newlines.
1662     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1663        a pointer to an int instead of a pointer to an unsigned long int. This
1664        caused problems on 64-bit systems.
1666     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1667        instance of the 'standard' template library not being so standard".
1669    10. There was no check on the number of named subpatterns nor the maximum
1670        length of a subpattern name. The product of these values is used to compute
1671        the size of the memory block for a compiled pattern. By supplying a very
1672        long subpattern name and a large number of named subpatterns, the size
1673        computation could be caused to overflow. This is now prevented by limiting
1674        the length of names to 32 characters, and the number of named subpatterns
1675        to 10,000.
1677    11. Subpatterns that are repeated with specific counts have to be replicated in
1678        the compiled pattern. The size of memory for this was computed from the
1679        length of the subpattern and the repeat count. The latter is limited to
1680        65535, but there was no limit on the former, meaning that integer overflow
1681        could in principle occur. The compiled length of a repeated subpattern is
1682        now limited to 30,000 bytes in order to prevent this.
1684    12. Added the optional facility to have named substrings with the same name.
1686    13. Added the ability to use a named substring as a condition, using the
1687        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1688        are numbers (not recommended). Forward references are permitted.
1690    14. Added forward references in named backreferences (if you see what I mean).
1692    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1693        pattern could run off the end of the subject. For example, the pattern
1694        "(?s)(.{1,5})"8 did this with the subject "ab".
1696    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1697        PCRE_CASELESS was set when matching characters that were quantified with ?
1698        or *.
1700    17. A character class other than a single negated character that had a minimum
1701        but no maximum quantifier - for example [ab]{6,} - was not handled
1702        correctly by pce_dfa_exec(). It would match only one character.
1704    18. A valid (though odd) pattern that looked like a POSIX character
1705        class but used an invalid character after [ (for example [[,abc,]]) caused
1706        pcre_compile() to give the error "Failed: internal error: code overflow" or
1707        in some cases to crash with a glibc free() error. This could even happen if
1708        the pattern terminated after [[ but there just happened to be a sequence of
1709        letters, a binary zero, and a closing ] in the memory that followed.
1711    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1712        over the years. Originally (before any Unicode support), just the bottom 8
1713        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1714        output from "man perlunicode" includes this:
1716          The regular expression compiler produces polymorphic opcodes.  That
1717          is, the pattern adapts to the data and automatically switches to
1718          the Unicode character scheme when presented with Unicode data--or
1719          instead uses a traditional byte scheme when presented with byte
1720          data.
1722        Sadly, a wide octal escape does not cause a switch, and in a string with
1723        no other multibyte characters, these octal escapes are treated as before.
1724        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1725        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1726        Unicode string.
1728        I have not perpetrated such confusion in PCRE. Up till now, it took just
1729        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1730        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1731        translate to the appropriate multibyte character.
1733    29. Applied some refactoring to reduce the number of warnings from Microsoft
1734        and Borland compilers. This has included removing the fudge introduced
1735        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1736        a warning about an unused variable.
1738    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1739        characters since release 4.0, because Perl (from release 5.004) does not.
1740        [Or at least, is documented not to: some releases seem to be in conflict
1741        with the documentation.] However, when a pattern was studied with
1742        pcre_study() and all its branches started with \s, PCRE still included VT
1743        as a possible starting character. Of course, this did no harm; it just
1744        caused an unnecessary match attempt.
1746    22. Removed a now-redundant internal flag bit that recorded the fact that case
1747        dependency changed within the pattern. This was once needed for "required
1748        byte" processing, but is no longer used. This recovers a now-scarce options
1749        bit. Also moved the least significant internal flag bit to the most-
1750        significant bit of the word, which was not previously used (hangover from
1751        the days when it was an int rather than a uint) to free up another bit for
1752        the future.
1754    23. Added support for CRLF line endings as well as CR and LF. As well as the
1755        default being selectable at build time, it can now be changed at runtime
1756        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1757        specify that it is scanning data with non-default line endings.
1759    24. Changed the definition of CXXLINK to make it agree with the definition of
1760        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1762    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1763        recursions. This makes a big different to stack usage for some patterns.
1765    26. If a subpattern containing a named recursion or subroutine reference such
1766        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1767        the space required for the compiled pattern went wrong and gave too small a
1768        value. Depending on the environment, this could lead to "Failed: internal
1769        error: code overflow at offset 49" or "glibc detected double free or
1770        corruption" errors.
1772    27. Applied patches from Google (a) to support the new newline modes and (b) to
1773        advance over multibyte UTF-8 characters in GlobalReplace.
1775    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1776        difference for some implementation of PCRE in some Windows version.
1778    29. Added some extra testing facilities to pcretest:
1780        \q<number>   in a data line sets the "match limit" value
1781        \Q<number>   in a data line sets the "match recursion limt" value
1782        -S <number>  sets the stack size, where <number> is in megabytes
1784        The -S option isn't available for Windows.
1787    Version 6.6 06-Feb-06
1788    ---------------------
1790     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1791        in pcreposix.h. I have copied the definition from pcre.h.
1793     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1794        because pcre.h is no longer a built file.
1796     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1797        not normally included in the compiled code.
1800    Version 6.5 01-Feb-06
1801    ---------------------
1803     1. When using the partial match feature with pcre_dfa_exec(), it was not
1804        anchoring the second and subsequent partial matches at the new starting
1805        point. This could lead to incorrect results. For example, with the pattern
1806        /1234/, partially matching against "123" and then "a4" gave a match.
1808     2. Changes to pcregrep:
1810        (a) All non-match returns from pcre_exec() were being treated as failures
1811            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1812            error message is output. Some extra information is given for the
1813            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1814            probably the only errors that are likely to be caused by users (by
1815            specifying a regex that has nested indefinite repeats, for instance).
1816            If there are more than 20 of these errors, pcregrep is abandoned.
1818        (b) A binary zero was treated as data while matching, but terminated the
1819            output line if it was written out. This has been fixed: binary zeroes
1820            are now no different to any other data bytes.
1822        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1823            used to set a locale for matching. The --locale=xxxx long option has
1824            been added (no short equivalent) to specify a locale explicitly on the
1825            pcregrep command, overriding the environment variables.
1827        (d) When -B was used with -n, some line numbers in the output were one less
1828            than they should have been.
1830        (e) Added the -o (--only-matching) option.
1832        (f) If -A or -C was used with -c (count only), some lines of context were
1833            accidentally printed for the final match.
1835        (g) Added the -H (--with-filename) option.
1837        (h) The combination of options -rh failed to suppress file names for files
1838            that were found from directory arguments.
1840        (i) Added the -D (--devices) and -d (--directories) options.
1842        (j) Added the -F (--fixed-strings) option.
1844        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1846        (l) Added the --colo(u)r option.
1848        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1849            is not present by default.
1851     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1852        items such as (?R) or (?1), when the recursion could match a number of
1853        alternatives. If it matched one of the alternatives, but subsequently,
1854        outside the recursion, there was a failure, the code tried to back up into
1855        the recursion. However, because of the way PCRE is implemented, this is not
1856        possible, and the result was an incorrect result from the match.
1858        In order to prevent this happening, the specification of recursion has
1859        been changed so that all such subpatterns are automatically treated as
1860        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1862     4. I had overlooked the fact that, in some locales, there are characters for
1863        which isalpha() is true but neither isupper() nor islower() are true. In
1864        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1865        and ordfeminine) are like this. This affected the treatment of \w and \W
1866        when they appeared in character classes, but not when they appeared outside
1867        a character class. The bit map for "word" characters is now created
1868        separately from the results of isalnum() instead of just taking it from the
1869        upper, lower, and digit maps. (Plus the underscore character, of course.)
1871     5. The above bug also affected the handling of POSIX character classes such as
1872        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1873        permanent tables. Instead, the bit maps for such a class were previously
1874        created as the appropriate unions of the upper, lower, and digit bitmaps.
1875        Now they are created by subtraction from the [[:word:]] class, which has
1876        its own bitmap.
1878     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1879        It is created by subtracting the vertical space characters (\x09, \x0a,
1880        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1881        subtraction was done in the overall bitmap for a character class, meaning
1882        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1883        be recognized. This bug has been fixed.
1885     7. Patches from the folks at Google:
1887          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1888          real life, but is still worth protecting against".
1890          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1891          regular expressions".
1893          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1894          have it.
1896          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1897          "configure" and the latter not, in order to fix a problem somebody had
1898          with compiling the Arg class on HP-UX.
1900          (e) Improve the error-handling of the C++ wrapper a little bit.
1902          (f) New tests for checking recursion limiting.
1904     8. The pcre_memmove() function, which is used only if the environment does not
1905        have a standard memmove() function (and is therefore rarely compiled),
1906        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1907        returning a result (though PCRE never actually uses the result).
1909     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1910        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1911        returned instead of calling malloc() with an overflowing number that would
1912        most likely cause subsequent chaos.
1914    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1916    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1917        with this option is matched, the nmatch and pmatch options of regexec() are
1918        ignored.
1920    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1921        provided in case anyone wants to the the POSIX interface with UTF-8
1922        strings.
1924    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1925        C++ linking (needed for some HP-UX environments).
1927    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1928        (unused parameter) and in the pcre_printint() function (omitted "default"
1929        switch label when the default is to do nothing).
1931    15. Added some code to make it possible, when PCRE is compiled as a C++
1932        library, to replace subject pointers for pcre_exec() with a smart pointer
1933        class, thus making it possible to process discontinuous strings.
1935    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1936        much the same function. They were added by different people who were trying
1937        to make PCRE easy to compile on non-Unix systems. It has been suggested
1938        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1939        for compiling on Windows systems. I have therefore replaced it with
1940        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1941        defaults to "extern" for C or "extern C" for C++, which works fine on
1942        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1943        SCOPE with something explicit in config.h. In addition:
1945        (a) pcreposix.h still had just "extern" instead of either of these macros;
1946            I have replaced it with PCRE_DATA_SCOPE.
1948        (b) Functions such as _pcre_xclass(), which are internal to the library,
1949            but external in the C sense, all had PCRE_EXPORT in their definitions.
1950            This is apparently wrong for the Windows case, so I have removed it.
1951            (It makes no difference on Unix-like systems.)
1953    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1954        of recursive calls to match(). This is different to MATCH_LIMIT because
1955        that limits the total number of calls to match(), not all of which increase
1956        the depth of recursion. Limiting the recursion depth limits the amount of
1957        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1958        when PCRE is compiled, and changed at run time. A patch from Google adds
1959        this functionality to the C++ interface.
1961    18. Changes to the handling of Unicode character properties:
1963        (a) Updated the table to Unicode 4.1.0.
1965        (b) Recognize characters that are not in the table as "Cn" (undefined).
1967        (c) I revised the way the table is implemented to a much improved format
1968            which includes recognition of ranges. It now supports the ranges that
1969            are defined in UnicodeData.txt, and it also amalgamates other
1970            characters into ranges. This has reduced the number of entries in the
1971            table from around 16,000 to around 3,000, thus reducing its size
1972            considerably. I realized I did not need to use a tree structure after
1973            all - a binary chop search is just as efficient. Having reduced the
1974            number of entries, I extended their size from 6 bytes to 8 bytes to
1975            allow for more data.
1977        (d) Added support for Unicode script names via properties such as \p{Han}.
1979    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1980        matching that character.
1982    20. When matching a repeated Unicode property with a minimum greater than zero,
1983        (for example \pL{2,}), PCRE could look past the end of the subject if it
1984        reached it while seeking the minimum number of characters. This could
1985        happen only if some of the characters were more than one byte long, because
1986        there is a check for at least the minimum number of bytes.
1988    21. Refactored the implementation of \p and \P so as to be more general, to
1989        allow for more different types of property in future. This has changed the
1990        compiled form incompatibly. Anybody with saved compiled patterns that use
1991        \p or \P will have to recompile them.
1993    22. Added "Any" and "L&" to the supported property types.
1995    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1996        but give a compile time error if the value is greater than 0xff.
1998    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1999        accidentally not being installed or uninstalled.
2001    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2002        made were to insert the current release number. This seemed silly, because
2003        it made things harder for people building PCRE on systems that don't run
2004        "configure". I have turned pcre.h into a distributed file, no longer built
2005        by "configure", with the version identification directly included. There is
2006        no longer a pcre.h.in file.
2008        However, this change necessitated a change to the pcre-config script as
2009        well. It is built from pcre-config.in, and one of the substitutions was the
2010        release number. I have updated configure.ac so that ./configure now finds
2011        the release number by grepping pcre.h.
2013    26. Added the ability to run the tests under valgrind.
2016    Version 6.4 05-Sep-05
2017    ---------------------
2019     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2020        "--" to be printed when multiple files were scanned, even when none of the
2021        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2022        consider it to be a bug, and have restored the previous behaviour.
2024     2. A couple of code tidies to get rid of compiler warnings.
2026     3. The pcretest program used to cheat by referring to symbols in the library
2027        whose names begin with _pcre_. These are internal symbols that are not
2028        really supposed to be visible externally, and in some environments it is
2029        possible to suppress them. The cheating is now confined to including
2030        certain files from the library's source, which is a bit cleaner.
2032     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2033        file's purpose clearer.
2035     5. Reorganized pcre_ucp_findchar().
2038    Version 6.3 15-Aug-05
2039    ---------------------
2041     1. The file libpcre.pc.in did not have general read permission in the tarball.
2043     2. There were some problems when building without C++ support:
2045        (a) If C++ support was not built, "make install" and "make test" still
2046            tried to test it.
2048        (b) There were problems when the value of CXX was explicitly set. Some
2049            changes have been made to try to fix these, and ...
2051        (c) --disable-cpp can now be used to explicitly disable C++ support.
2053        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2054            backslash in a target when C++ was disabled. This confuses some
2055            versions of "make", apparently. Using an intermediate variable solves
2056            this. (Same for CPP_LOBJ.)
2058     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2059        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2060        necessary on certain architectures.
2062     4. Added a setting of -export-symbols-regex to the link command to remove
2063        those symbols that are exported in the C sense, but actually are local
2064        within the library, and not documented. Their names all begin with
2065        "_pcre_". This is not a perfect job, because (a) we have to except some
2066        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2067        available (and never for static libraries). I have made a note to try to
2068        find a way round (a) in the future.
2071    Version 6.2 01-Aug-05
2072    ---------------------
2074     1. There was no test for integer overflow of quantifier values. A construction
2075        such as {1111111111111111} would give undefined results. What is worse, if
2076        a minimum quantifier for a parenthesized subpattern overflowed and became
2077        negative, the calculation of the memory size went wrong. This could have
2078        led to memory overwriting.
2080     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2082     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2083        operating environments where this matters.
2085     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2086        PCRE options from within the C++ wrapper.
2088     5. Named capturing subpatterns were not being correctly counted when a pattern
2089        was compiled. This caused two problems: (a) If there were more than 100
2090        such subpatterns, the calculation of the memory needed for the whole
2091        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2092        back references of the form \12, where the number was greater than 9, were
2093        not recognized as back references, even though there were sufficient
2094        previous subpatterns.
2096     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2097        versions of gcc, e.g. 2.95.4.
2100    Version 6.1 21-Jun-05
2101    ---------------------
2103     1. There was one reference to the variable "posix" in pcretest.c that was not
2104        surrounded by "#if !defined NOPOSIX".
2106     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2107        the cross-check on the old pcre_info() function, for the benefit of the
2108        cut-down version of PCRE that is currently imported into Exim.
2110     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2111        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2112        patterns that start (?i) but I don't think that matters. The use of (?i) is
2113        just an example; this all applies to the other options as well.
2115     4. Since libtool seems to echo the compile commands it is issuing, the output
2116        from "make" can be reduced a bit by putting "@" in front of each libtool
2117        compile command.
2119     5. Patch from the folks at Google for configure.in to be a bit more thorough
2120        in checking for a suitable C++ installation before trying to compile the
2121        C++ stuff. This should fix a reported problem when a compiler was present,
2122        but no suitable headers.
2124     6. The man pages all had just "PCRE" as their title. I have changed them to
2125        be the relevant file name. I have also arranged that these names are
2126        retained in the file doc/pcre.txt, which is a concatenation in text format
2127        of all the man pages except the little individual ones for each function.
2129     7. The NON-UNIX-USE file had not been updated for the different set of source
2130        files that come with release 6. I also added a few comments about the C++
2131        wrapper.
2134    Version 6.0 07-Jun-05
2135    ---------------------
2137     1. Some minor internal re-organization to help with my DFA experiments.
2139     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2140        didn't matter for the library itself when fully configured, but did matter
2141        when compiling without UCP support, or within Exim, where the ucp files are
2142        not imported.
2144     3. Refactoring of the library code to split up the various functions into
2145        different source modules. The addition of the new DFA matching code (see
2146        below) to a single monolithic source would have made it really too
2147        unwieldy, quite apart from causing all the code to be include in a
2148        statically linked application, when only some functions are used. This is
2149        relevant even without the DFA addition now that patterns can be compiled in
2150        one application and matched in another.
2152        The downside of splitting up is that there have to be some external
2153        functions and data tables that are used internally in different modules of
2154        the library but which are not part of the API. These have all had their
2155        names changed to start with "_pcre_" so that they are unlikely to clash
2156        with other external names.
2158     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2159        a different (DFA) algorithm. Although it is slower than the original
2160        function, it does have some advantages for certain types of matching
2161        problem.
2163     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2164        including restarting after a partial match.
2166     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2167        defined when compiling for Windows was sent to me. I have put it into the
2168        code, though I have no means of testing or verifying it.
2170     7. Added the pcre_refcount() auxiliary function.
2172     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2173        match before or at the first newline in the subject string. In pcretest,
2174        the /f option on a pattern can be used to set this.
2176     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2177        would behave wrongly. This has been present in PCRE since release 4.0.
2179    10. A number of changes to the pcregrep command:
2181        (a) Refactored how -x works; insert ^(...)$ instead of setting
2182            PCRE_ANCHORED and checking the length, in preparation for adding
2183            something similar for -w.
2185        (b) Added the -w (match as a word) option.
2187        (c) Refactored the way lines are read and buffered so as to have more
2188            than one at a time available.
2190        (d) Implemented a pcregrep test script.
2192        (e) Added the -M (multiline match) option. This allows patterns to match
2193            over several lines of the subject. The buffering ensures that at least
2194            8K, or the rest of the document (whichever is the shorter) is available
2195            for matching (and similarly the previous 8K for lookbehind assertions).
2197        (f) Changed the --help output so that it now says
2199              -w, --word-regex(p)
2201            instead of two lines, one with "regex" and the other with "regexp"
2202            because that confused at least one person since the short forms are the
2203            same. (This required a bit of code, as the output is generated
2204            automatically from a table. It wasn't just a text change.)
2206        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2207            option but starts with a hyphen. Could be a pattern or a path name
2208            starting with a hyphen, for instance.
2210        (h) "-" can be given as a file name to represent stdin.
2212        (i) When file names are being printed, "(standard input)" is used for
2213            the standard input, for compatibility with GNU grep. Previously
2214            "<stdin>" was used.
2216        (j) The option --label=xxx can be used to supply a name to be used for
2217            stdin when file names are being printed. There is no short form.
2219        (k) Re-factored the options decoding logic because we are going to add
2220            two more options that take data. Such options can now be given in four
2221            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2223        (l) Added the -A, -B, and -C options for requesting that lines of context
2224            around matches be printed.
2226        (m) Added the -L option to print the names of files that do not contain
2227            any matching lines, that is, the complement of -l.
2229        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2230            continue to scan other files.
2232        (o) The -s option was incorrectly implemented. For compatibility with other
2233            greps, it now suppresses the error message for a non-existent or non-
2234            accessible file (but not the return code). There is a new option called
2235            -q that suppresses the output of matching lines, which was what -s was
2236            previously doing.
2238        (p) Added --include and --exclude options to specify files for inclusion
2239            and exclusion when recursing.
2241    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2242        Hopefully, it now does.
2244    12. Missing cast in pcre_study().
2246    13. Added an "uninstall" target to the makefile.
2248    14. Replaced "extern" in the function prototypes in Makefile.in with
2249        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2250        world, but is set differently for Windows.
2252    15. Added a second compiling function called pcre_compile2(). The only
2253        difference is that it has an extra argument, which is a pointer to an
2254        integer error code. When there is a compile-time failure, this is set
2255        non-zero, in addition to the error test pointer being set to point to an
2256        error message. The new argument may be NULL if no error number is required
2257        (but then you may as well call pcre_compile(), which is now just a
2258        wrapper). This facility is provided because some applications need a
2259        numeric error indication, but it has also enabled me to tidy up the way
2260        compile-time errors are handled in the POSIX wrapper.
2262    16. Added VPATH=.libs to the makefile; this should help when building with one
2263        prefix path and installing with another. (Or so I'm told by someone who
2264        knows more about this stuff than I do.)
2266    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2267        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2268        match everything, including newlines. This is not POSIX-compatible, but
2269        somebody wanted the feature. From pcretest it can be activated by using
2270        both the P and the s flags.
2272    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2274    19. libpcre.pc was being incorrectly installed as executable.
2276    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2277        it now also looks for '\r' so that it will work unmodified on Windows.
2279    21. Added Google's contributed C++ wrapper to the distribution.
2281    22. Added some untidy missing memory free() calls in pcretest, to keep
2282        Electric Fence happy when testing.
2286    Version 5.0 13-Sep-04
2287    ---------------------
2289     1. Internal change: literal characters are no longer packed up into items
2290        containing multiple characters in a single byte-string. Each character
2291        is now matched using a separate opcode. However, there may be more than one
2292        byte in the character in UTF-8 mode.
2294     2. The pcre_callout_block structure has two new fields: pattern_position and
2295        next_item_length. These contain the offset in the pattern to the next match
2296        item, and its length, respectively.
2298     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2299        insertion of callouts before each pattern item. Added the /C option to
2300        pcretest to make use of this.
2302     4. On the advice of a Windows user, the lines
2304          #if defined(_WIN32) || defined(WIN32)
2305          _setmode( _fileno( stdout ), 0x8000 );
2306          #endif  /* defined(_WIN32) || defined(WIN32) */
2308        have been added to the source of pcretest. This apparently does useful
2309        magic in relation to line terminators.
2311     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2312        for the benefit of those environments where the "b" makes a difference.
2314     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2315        to know about it. I have put a hack into configure.in that adds in code
2316        to set GCC=yes if CC=icc. This seems to end up at a point in the
2317        generated configure script that is early enough to affect the setting of
2318        compiler options, which is what is needed, but I have no means of testing
2319        whether it really works. (The user who reported this had patched the
2320        generated configure script, which of course I cannot do.)
2322        LATER: After change 22 below (new libtool files), the configure script
2323        seems to know about icc (and also ecc). Therefore, I have commented out
2324        this hack in configure.in.
2326     7. Added support for pkg-config (2 patches were sent in).
2328     8. Negated POSIX character classes that used a combination of internal tables
2329        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2330        [[:^ascii]]. Typically, they would match almost any characters. The other
2331        POSIX classes were not broken in this way.
2333     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2334        to find the match, as PCRE was deluded into thinking that the match had to
2335        start at the start point or following a newline. The same bug applied to
2336        patterns with negative forward assertions or any backward assertions
2337        preceding ".*" at the start, unless the pattern required a fixed first
2338        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2340    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2341        starting at the last subject character, bytes beyond the end of the subject
2342        string were read.
2344    11. Renamed the variable "class" as "classbits" to make life easier for C++
2345        users. (Previously there was a macro definition, but it apparently wasn't
2346        enough.)
2348    12. Added the new field "tables" to the extra data so that tables can be passed
2349        in at exec time, or the internal tables can be re-selected. This allows
2350        a compiled regex to be saved and re-used at a later time by a different
2351        program that might have everything at different addresses.
2353    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2354        -R library as well as a -L library.
2356    14. The debugging options of pcretest (-d on the command line or D on a
2357        pattern) showed incorrect output for anything following an extended class
2358        that contained multibyte characters and which was followed by a quantifier.
2360    15. Added optional support for general category Unicode character properties
2361        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2362        support. It adds about 90K to the size of the library. The meanings of the
2363        inbuilt class escapes such as \d and \s have NOT been changed.
2365    16. Updated pcredemo.c to include calls to free() to release the memory for the
2366        compiled pattern.
2368    17. The generated file chartables.c was being created in the source directory
2369        instead of in the building directory. This caused the build to fail if the
2370        source directory was different from the building directory, and was
2371        read-only.
2373    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2374        file. No doubt somebody will tell me if they don't make sense... Also added
2375        Dan Mooney's comments about building on OpenVMS.
2377    19. Added support for partial matching via the PCRE_PARTIAL option for
2378        pcre_exec() and the \P data escape in pcretest.
2380    20. Extended pcretest with 3 new pattern features:
2382        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2383              write the compiled pattern to the file whose name is "rest-of-line".
2384              This is a straight binary dump of the data, with the saved pointer to
2385              the character tables forced to be NULL. The study data, if any, is
2386              written too. After writing, pcretest reads a new pattern.
2388        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2389              compiled pattern from the given file. There must not be any
2390              occurrences of "<" in the file name (pretty unlikely); if there are,
2391              pcretest will instead treat the initial "<" as a pattern delimiter.
2392              After reading in the pattern, pcretest goes on to read data lines as
2393              usual.
2395        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2396              and 16-bit fields in a compiled pattern, to simulate a pattern that
2397              was compiled on a host of opposite endianness.
2399    21. The pcre-exec() function can now cope with patterns that were compiled on
2400        hosts of opposite endianness, with this restriction:
2402          As for any compiled expression that is saved and used later, the tables
2403          pointer field cannot be preserved; the extra_data field in the arguments
2404          to pcre_exec() should be used to pass in a tables address if a value
2405          other than the default internal tables were used at compile time.
2407    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2408        now diagnosed as an error. Previously, most of the time, a negative number
2409        would have been treated as zero, but if in addition "ovector" was passed as
2410        NULL, a crash could occur.
2412    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2413        new versions from the libtool 1.5 distribution (the last one is a copy of
2414        a file called libtool.m4). This seems to have fixed the need to patch
2415        "configure" to support Darwin 1.3 (which I used to do). However, I still
2416        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2417        workstation).
2419    24. Changed the PCRE licence to be the more standard "BSD" licence.
2422    Version 4.5 01-Dec-03
2423    ---------------------
2425     1. There has been some re-arrangement of the code for the match() function so
2426        that it can be compiled in a version that does not call itself recursively.
2427        Instead, it keeps those local variables that need separate instances for
2428        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2429        needs to "recurse". Keeping track of where control must go is done by means
2430        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2431        hide most of the details from the main code, and operates only if
2432        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2433        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2434        operating.
2436        To make it easier for callers to provide specially tailored get/free
2437        functions for this usage, two new functions, pcre_stack_malloc, and
2438        pcre_stack_free, are used. They are always called in strict stacking order,
2439        and the size of block requested is always the same.
2441        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2442        PCRE has been compiled to use the stack or the heap for recursion. The
2443        -C option of pcretest uses this to show which version is compiled.
2445        A new data escape \S, is added to pcretest; it causes the amounts of store
2446        obtained and freed by both kinds of malloc/free at match time to be added
2447        to the output.
2449     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2450        what's available on my current Linux desktop machine.
2452     3. When matching a UTF-8 string, the test for a valid string at the start has
2453        been extended. If start_offset is not zero, PCRE now checks that it points
2454        to a byte that is the start of a UTF-8 character. If not, it returns
2455        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2456        this is necessary because there may be backward assertions in the pattern.
2457        When matching the same subject several times, it may save resources to use
2458        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2460     4. The code for checking the validity of UTF-8 strings has been tightened so
2461        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2462        containing "overlong sequences".
2464     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2465        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2466        should have been "&", but it just so happened that all the cases this let
2467        through by mistake were picked up later in the function.
2469     6. I had used a variable called "isblank" - this is a C99 function, causing
2470        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2472     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2473        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2474        so the version is shown; (c) stop "make test" echoing "./RunTest".
2476     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2478     9. The prototype for memmove() for systems that don't have it was using
2479        size_t, but the inclusion of the header that defines size_t was later. I've
2480        moved the #includes for the C headers earlier to avoid this.
2482    10. Added some adjustments to the code to make it easier to compiler on certain
2483        special systems:
2485          (a) Some "const" qualifiers were missing.
2486          (b) Added the macro EXPORT before all exported functions; by default this
2487              is defined to be empty.
2488          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2489              that it reads its output file name as an argument instead of writing
2490              to the standard output and assuming this can be redirected.
2492    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2493        class containing characters with values greater than 255, PCRE compilation
2494        went into a loop.
2496    12. A recursive reference to a subpattern that was within another subpattern
2497        that had a minimum quantifier of zero caused PCRE to crash. For example,
2498        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2499        recursion. If the recursively-called subpattern itself had a zero repeat,
2500        that was OK.
2502    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2503        buffer into which it was copied (for escape processing) was still set at
2504        1024, so long lines caused crashes.
2506    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2507        "internal error: code overflow...". This applied to any character class
2508        that was followed by a possessive quantifier.
2510    15. Modified the Makefile to add libpcre.la as a prerequisite for
2511        libpcreposix.la because I was told this is needed for a parallel build to
2512        work.
2514    16. If a pattern that contained .* following optional items at the start was
2515        studied, the wrong optimizing data was generated, leading to matching
2516        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2517        matching string must start with a or b or c. The correct conclusion for
2518        this pattern is that a match can start with any character.
2521    Version 4.4 13-Aug-03
2522    ---------------------
2524     1. In UTF-8 mode, a character class containing characters with values between
2525        127 and 255 was not handled correctly if the compiled pattern was studied.
2526        In fixing this, I have also improved the studying algorithm for such
2527        classes (slightly).
2529     2. Three internal functions had redundant arguments passed to them. Removal
2530        might give a very teeny performance improvement.
2532     3. Documentation bug: the value of the capture_top field in a callout is *one
2533        more than* the number of the hightest numbered captured substring.
2535     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2536        in incorrectly linking with a previously installed version. They now link
2537        explicitly with libpcre.la.
2539     5. configure.in no longer needs to recognize Cygwin specially.
2541     6. A problem in pcre.in for Windows platforms is fixed.
2543     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2544        pcretest, it used to include the size of the study block as part of its
2545        output. Unfortunately, the structure contains a field that has a different
2546        size on different hardware architectures. This meant that the tests that
2547        showed this size failed. As the block is currently always of a fixed size,
2548        this information isn't actually particularly useful in pcretest output, so
2549        I have just removed it.
2551     8. Three pre-processor statements accidentally did not start in column 1.
2552        Sadly, there are *still* compilers around that complain, even though
2553        standard C has not required this for well over a decade. Sigh.
2555     9. In pcretest, the code for checking callouts passed small integers in the
2556        callout_data field, which is a void * field. However, some picky compilers
2557        complained about the casts involved for this on 64-bit systems. Now
2558        pcretest passes the address of the small integer instead, which should get
2559        rid of the warnings.
2561    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2562        both compile and run time, and gives an error if an invalid UTF-8 sequence
2563        is found. There is a option for disabling this check in cases where the
2564        string is known to be correct and/or the maximum performance is wanted.
2566    11. In response to a bug report, I changed one line in Makefile.in from
2568            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2569        to
2570            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2572        to look similar to other lines, but I have no way of telling whether this
2573        is the right thing to do, as I do not use Windows. No doubt I'll get told
2574        if it's wrong...
2577  Version 4.3 21-May-03  Version 4.3 21-May-03
2578  ---------------------  ---------------------

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