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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.03 26-Mar-2010
5    ------------------------
6    
7    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
8        THEN.
9    
10    2.  (*ACCEPT) was not working when inside an atomic group.
11    
12    
13    Version 8.02 19-Mar-2010
14    ------------------------
15    
16    1.  The Unicode data tables have been updated to Unicode 5.2.0.
17    
18    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
19        configured.
20    
21    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
22        original author of that file, following a query about its status.
23    
24    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
25        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
26    
27    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
28        quantifier applied to a forward-referencing subroutine call, could compile
29        incorrect code or give the error "internal error: previously-checked
30        referenced subpattern not found".
31    
32    6.  Both MS Visual Studio and Symbian OS have problems with initializing
33        variables to point to external functions. For these systems, therefore,
34        pcre_malloc etc. are now initialized to local functions that call the
35        relevant global functions.
36    
37    7.  There were two entries missing in the vectors called coptable and poptable
38        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
39        I've fixed the data, and added a kludgy way of testing at compile time that
40        the lengths are correct (equal to the number of opcodes).
41    
42    8.  Following on from 7, I added a similar kludge to check the length of the
43        eint vector in pcreposix.c.
44    
45    9.  Error texts for pcre_compile() are held as one long string to avoid too
46        much relocation at load time. To find a text, the string is searched,
47        counting zeros. There was no check for running off the end of the string,
48        which could happen if a new error number was added without updating the
49        string.
50    
51    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
52    
53    11. \K was not working if it appeared in an atomic group or in a group that
54        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
55        \K is "not well defined" if used in an assertion. PCRE now accepts it if
56        the assertion is positive, but not if it is negative.
57    
58    12. Change 11 fortuitously reduced the size of the stack frame used in the
59        "match()" function of pcre_exec.c by one pointer. Forthcoming
60        implementation of support for (*MARK) will need an extra pointer on the
61        stack; I have reserved it now, so that the stack frame size does not
62        decrease.
63    
64    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
65        item in branch that calls a recursion is a subroutine call - as in the
66        second branch in the above example - was incorrectly given the compile-
67        time error "recursive call could loop indefinitely" because pcre_compile()
68        was not correctly checking the subroutine for matching a non-empty string.
69    
70    14. The checks for overrunning compiling workspace could trigger after an
71        overrun had occurred. This is a "should never occur" error, but it can be
72        triggered by pathological patterns such as hundreds of nested parentheses.
73        The checks now trigger 100 bytes before the end of the workspace.
74    
75    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
76    
77    
78    Version 8.01 19-Jan-2010
79    ------------------------
80    
81    1.  If a pattern contained a conditional subpattern with only one branch (in
82        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
83        computed the wrong minimum data length (which is of course zero for such
84        subpatterns). This could cause incorrect "no match" results.
85    
86    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
87        the pattern is reset in the first branch, pcre_compile() failed with
88        "internal error: code overflow at offset...". This happened only when
89        the reset was to the original external option setting. (An optimization
90        abstracts leading options settings into an external setting, which was the
91        cause of this.)
92    
93    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
94        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
95        assertion pattern did not match (meaning that the assertion was true), it
96        was incorrectly treated as false if the SKIP had been reached during the
97        matching. This also applied to assertions used as conditions.
98    
99    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
100        assertion subpattern, including such a pattern used as a condition,
101        unpredictable results occurred, instead of the error return
102        PCRE_ERROR_DFA_UITEM.
103    
104    5.  The C++ GlobalReplace function was not working like Perl for the special
105        situation when an empty string is matched. It now does the fancy magic
106        stuff that is necessary.
107    
108    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
109        removed. (These were left over from very, very early versions of PCRE.)
110    
111    7.  Some cosmetic changes to the code to make life easier when compiling it
112        as part of something else:
113    
114        (a) Change DEBUG to PCRE_DEBUG.
115    
116        (b) In pcre_compile(), rename the member of the "branch_chain" structure
117            called "current" as "current_branch", to prevent a collision with the
118            Linux macro when compiled as a kernel module.
119    
120        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
121            prevent a collision with the Linux macro when compiled as a kernel
122            module.
123    
124    8.  In pcre_compile() there are some checks for integer overflows that used to
125        cast potentially large values to (double). This has been changed to that
126        when building, a check for int64_t is made, and if it is found, it is used
127        instead, thus avoiding the use of floating point arithmetic. (There is no
128        other use of FP in PCRE.) If int64_t is not found, the fallback is to
129        double.
130    
131    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
132        2005 (difference between two addresses compared to an unsigned value).
133    
134    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
135        custom one, because of the following reported problem in Windows:
136    
137          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
138              under Win32.
139          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
140              therefore missing the function definition.
141          - The compiler thus generates a "C" signature for the test function.
142          - The linker fails to find the "C" function.
143          - PCRE fails to configure if asked to do so against libbz2.
144    
145    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
146        messages were output:
147    
148          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
149          rerunning libtoolize, to keep the correct libtool macros in-tree.
150          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
151    
152        I have done both of these things.
153    
154    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
155        most of the time, it *can* run out if it is given a pattern that contains a
156        runaway infinite recursion. I updated the discussion in the pcrestack man
157        page.
158    
159    13. Now that we have gone to the x.xx style of version numbers, the minor
160        version may start with zero. Using 08 or 09 is a bad idea because users
161        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
162        interpreted as invalid octal numbers. I've updated the previous comment in
163        configure.ac, and also added a check that gives an error if 08 or 09 are
164        used.
165    
166    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
167        causing partial matching to fail when the end of the subject matched \W
168        in a UTF-8 pattern where \W was quantified with a minimum of 3.
169    
170    15. There were some discrepancies between the declarations in pcre_internal.h
171        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
172        their definitions. The declarations used "const uschar *" and the
173        definitions used USPTR. Even though USPTR is normally defined as "const
174        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
175        reported that: "This difference in casting confuses some C++ compilers, for
176        example, SunCC recognizes above declarations as different functions and
177        generates broken code for hbpcre." I have changed the declarations to use
178        USPTR.
179    
180    16. GNU libtool is named differently on some systems. The autogen.sh script now
181        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
182        (FreeBSD).
183    
184    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
185        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
186        comment: "Figure out how to create a longlong from a string: strtoll and
187        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
188        instance, but it only takes 2 args instead of 3!"
189    
190    18. A subtle bug concerned with back references has been fixed by a change of
191        specification, with a corresponding code fix. A pattern such as
192        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
193        refers, was giving matches when it shouldn't. For example, xa=xaaa would
194        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
195        same bug. Such groups have to be quantified to be useful, or contained
196        inside another quantified group. (If there's no repetition, the reference
197        can never match.) The problem arises because, having left the group and
198        moved on to the rest of the pattern, a later failure that backtracks into
199        the group uses the captured value from the final iteration of the group
200        rather than the correct earlier one. I have fixed this in PCRE by forcing
201        any group that contains a reference to itself to be an atomic group; that
202        is, there cannot be any backtracking into it once it has completed. This is
203        similar to recursive and subroutine calls.
204    
205    
206    Version 8.00 19-Oct-09
207    ----------------------
208    
209    1.  The table for translating pcre_compile() error codes into POSIX error codes
210        was out-of-date, and there was no check on the pcre_compile() error code
211        being within the table. This could lead to an OK return being given in
212        error.
213    
214    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
215        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
216        in a Windows environment.
217    
218    3.  The pcregrep --count option prints the count for each file even when it is
219        zero, as does GNU grep. However, pcregrep was also printing all files when
220        --files-with-matches was added. Now, when both options are given, it prints
221        counts only for those files that have at least one match. (GNU grep just
222        prints the file name in this circumstance, but including the count seems
223        more useful - otherwise, why use --count?) Also ensured that the
224        combination -clh just lists non-zero counts, with no names.
225    
226    4.  The long form of the pcregrep -F option was incorrectly implemented as
227        --fixed_strings instead of --fixed-strings. This is an incompatible change,
228        but it seems right to fix it, and I didn't think it was worth preserving
229        the old behaviour.
230    
231    5.  The command line items --regex=pattern and --regexp=pattern were not
232        recognized by pcregrep, which required --regex pattern or --regexp pattern
233        (with a space rather than an '='). The man page documented the '=' forms,
234        which are compatible with GNU grep; these now work.
235    
236    6.  No libpcreposix.pc file was created for pkg-config; there was just
237        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
238    
239    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
240        when UCP support is not needed, by modifying the Python script that
241        generates it from Unicode data files. This should not matter if the module
242        is correctly used as a library, but I received one complaint about 50K of
243        unwanted data. My guess is that the person linked everything into his
244        program rather than using a library. Anyway, it does no harm.
245    
246    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
247        was a minimum greater than 1 for a wide character in a possessive
248        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
249        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
250        character. Chaos in the form of incorrect output or a compiling loop could
251        result.
252    
253    9.  The restrictions on what a pattern can contain when partial matching is
254        requested for pcre_exec() have been removed. All patterns can now be
255        partially matched by this function. In addition, if there are at least two
256        slots in the offset vector, the offset of the earliest inspected character
257        for the match and the offset of the end of the subject are set in them when
258        PCRE_ERROR_PARTIAL is returned.
259    
260    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
261        synonymous with PCRE_PARTIAL, for backwards compatibility, and
262        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
263        and may be more useful for multi-segment matching.
264    
265    11. Partial matching with pcre_exec() is now more intuitive. A partial match
266        used to be given if ever the end of the subject was reached; now it is
267        given only if matching could not proceed because another character was
268        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
269        string "Z", which now yields "no match" instead of "partial match". In the
270        case of pcre_dfa_exec(), "no match" is given if every matching path for the
271        final character ended with (*FAIL).
272    
273    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
274        if the pattern had a "must contain" character that was already found in the
275        earlier partial match, unless partial matching was again requested. For
276        example, with the pattern /dog.(body)?/, the "must contain" character is
277        "g". If the first part-match was for the string "dog", restarting with
278        "sbody" failed. This bug has been fixed.
279    
280    13. The string returned by pcre_dfa_exec() after a partial match has been
281        changed so that it starts at the first inspected character rather than the
282        first character of the match. This makes a difference only if the pattern
283        starts with a lookbehind assertion or \b or \B (\K is not supported by
284        pcre_dfa_exec()). It's an incompatible change, but it makes the two
285        matching functions compatible, and I think it's the right thing to do.
286    
287    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
288        so that the demonstration program is easily available in environments where
289        PCRE has not been installed from source.
290    
291    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
292        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
293        library.
294    
295    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
296        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
297        is not the first non-POSIX option to be added. Clearly some people find
298        these options useful.
299    
300    17. If a caller to the POSIX matching function regexec() passes a non-zero
301        value for nmatch with a NULL value for pmatch, the value of
302        nmatch is forced to zero.
303    
304    18. RunGrepTest did not have a test for the availability of the -u option of
305        the diff command, as RunTest does. It now checks in the same way as
306        RunTest, and also checks for the -b option.
307    
308    19. If an odd number of negated classes containing just a single character
309        interposed, within parentheses, between a forward reference to a named
310        subpattern and the definition of the subpattern, compilation crashed with
311        an internal error, complaining that it could not find the referenced
312        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
313        [The bug was that it was starting one character too far in when skipping
314        over the character class, thus treating the ] as data rather than
315        terminating the class. This meant it could skip too much.]
316    
317    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
318        /g option in pcretest when the pattern contains \K, which makes it possible
319        to have an empty string match not at the start, even when the pattern is
320        anchored. Updated pcretest and pcredemo to use this option.
321    
322    21. If the maximum number of capturing subpatterns in a recursion was greater
323        than the maximum at the outer level, the higher number was returned, but
324        with unset values at the outer level. The correct (outer level) value is
325        now given.
326    
327    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
328        PCRE did not set those parentheses (unlike Perl). I have now found a way to
329        make it do so. The string so far is captured, making this feature
330        compatible with Perl.
331    
332    23. The tests have been re-organized, adding tests 11 and 12, to make it
333        possible to check the Perl 5.10 features against Perl 5.10.
334    
335    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
336        pattern matches a fixed length string. PCRE did not allow this; now it
337        does. Neither allows recursion.
338    
339    25. I finally figured out how to implement a request to provide the minimum
340        length of subject string that was needed in order to match a given pattern.
341        (It was back references and recursion that I had previously got hung up
342        on.) This code has now been added to pcre_study(); it finds a lower bound
343        to the length of subject needed. It is not necessarily the greatest lower
344        bound, but using it to avoid searching strings that are too short does give
345        some useful speed-ups. The value is available to calling programs via
346        pcre_fullinfo().
347    
348    26. While implementing 25, I discovered to my embarrassment that pcretest had
349        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
350        study optimizations had never been tested with that matching function.
351        Oops. What is worse, even when it was passed study data, there was a bug in
352        pcre_dfa_exec() that meant it never actually used it. Double oops. There
353        were also very few tests of studied patterns with pcre_dfa_exec().
354    
355    27. If (?| is used to create subpatterns with duplicate numbers, they are now
356        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
357        on the other side of the coin, they are no longer allowed to have different
358        names, because these cannot be distinguished in PCRE, and this has caused
359        confusion. (This is a difference from Perl.)
360    
361    28. When duplicate subpattern names are present (necessarily with different
362        numbers, as required by 27 above), and a test is made by name in a
363        conditional pattern, either for a subpattern having been matched, or for
364        recursion in such a pattern, all the associated numbered subpatterns are
365        tested, and the overall condition is true if the condition is true for any
366        one of them. This is the way Perl works, and is also more like the way
367        testing by number works.
368    
369    
370    Version 7.9 11-Apr-09
371    ---------------------
372    
373    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
374        (pcretest), all targets were linked against these libraries. This included
375        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
376        libraries. This caused unwanted dependencies to be created. This problem
377        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
378        pcretest is linked with readline.
379    
380    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
381        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
382        moved outside it again, because FALSE and TRUE are already defined in AIX,
383        but BOOL is not.
384    
385    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
386        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
387    
388    4.  The pcregrep documentation said spaces were inserted as well as colons (or
389        hyphens) following file names and line numbers when outputting matching
390        lines. This is not true; no spaces are inserted. I have also clarified the
391        wording for the --colour (or --color) option.
392    
393    5.  In pcregrep, when --colour was used with -o, the list of matching strings
394        was not coloured; this is different to GNU grep, so I have changed it to be
395        the same.
396    
397    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
398        each matching line was coloured. Now it goes on to look for further matches
399        of any of the test patterns, which is the same behaviour as GNU grep.
400    
401    7.  A pattern that could match an empty string could cause pcregrep to loop; it
402        doesn't make sense to accept an empty string match in pcregrep, so I have
403        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
404        seems to be how GNU grep behaves.
405    
406    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
407        start or after a newline", because the conditional assertion was not being
408        correctly handled. The rule now is that both the assertion and what follows
409        in the first alternative must satisfy the test.
410    
411    9.  If auto-callout was enabled in a pattern with a conditional group whose
412        condition was an assertion, PCRE could crash during matching, both with
413        pcre_exec() and pcre_dfa_exec().
414    
415    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
416        used for matching.
417    
418    11. Unicode property support in character classes was not working for
419        characters (bytes) greater than 127 when not in UTF-8 mode.
420    
421    12. Added the -M command line option to pcretest.
422    
423    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
424    
425    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
426    
427    16. Added comments and documentation about mis-use of no_arg in the C++
428        wrapper.
429    
430    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
431        from Martin Jerabek that uses macro names for all relevant character and
432        string constants.
433    
434    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
435        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
436        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
437        these, but not everybody uses configure.
438    
439    19. A conditional group that had only one branch was not being correctly
440        recognized as an item that could match an empty string. This meant that an
441        enclosing group might also not be so recognized, causing infinite looping
442        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
443        with the subject "ab", where knowledge that the repeated group can match
444        nothing is needed in order to break the loop.
445    
446    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
447        exec(), but without supplying a callout function, matching went wrong.
448    
449    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
450        leak if the size of the offset vector was greater than 30. When the vector
451        is smaller, the saved offsets during recursion go onto a local stack
452        vector, but for larger vectors malloc() is used. It was failing to free
453        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
454        error, in fact).
455    
456    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
457        heapframe that is used only when UTF-8 support is enabled. This caused no
458        problem, but was untidy.
459    
460    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
461        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
462        included within another project.
463    
464    24. Steven Van Ingelgem's patches to add more options to the CMake support,
465        slightly modified by me:
466    
467          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
468              not building pcregrep.
469    
470          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
471              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
472    
473    25. Forward references, both numeric and by name, in patterns that made use of
474        duplicate group numbers, could behave incorrectly or give incorrect errors,
475        because when scanning forward to find the reference group, PCRE was not
476        taking into account the duplicate group numbers. A pattern such as
477        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
478    
479    26. Changed a few more instances of "const unsigned char *" to USPTR, making
480        the feature of a custom pointer more persuasive (as requested by a user).
481    
482    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
483        pcretest.c, inside #ifndefs, because it seems they are sometimes already
484        pre-defined.
485    
486    28. Added support for (*UTF8) at the start of a pattern.
487    
488    29. Arrange for flags added by the "release type" setting in CMake to be shown
489        in the configuration summary.
490    
491    
492    Version 7.8 05-Sep-08
493    ---------------------
494    
495    1.  Replaced UCP searching code with optimized version as implemented for Ad
496        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
497        stage table and inline lookup instead of a function, giving speed ups of 2
498        to 5 times on some simple patterns that I tested. Permission was given to
499        distribute the MultiStage2.py script that generates the tables (it's not in
500        the tarball, but is in the Subversion repository).
501    
502    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
503        scripts.
504    
505    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
506        a group with a zero qualifier. The result of the study could be incorrect,
507        or the function might crash, depending on the pattern.
508    
509    4.  Caseless matching was not working for non-ASCII characters in back
510        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
511        It now works when Unicode Property Support is available.
512    
513    5.  In pcretest, an escape such as \x{de} in the data was always generating
514        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
515        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
516        truncation.
517    
518    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
519    
520    7.  Added two (int) casts to pcregrep when printing the difference of two
521        pointers, in case they are 64-bit values.
522    
523    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
524        test 2 if it fails.
525    
526    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
527        and a #define of that name to empty if it is not externally set. This is to
528        allow users of MSVC to set it if necessary.
529    
530    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
531        the convenience functions in the pcre_get.c source file.
532    
533    11. An option change at the start of a pattern that had top-level alternatives
534        could cause overwriting and/or a crash. This command provoked a crash in
535        some environments:
536    
537          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
538    
539        This potential security problem was recorded as CVE-2008-2371.
540    
541    12. For a pattern where the match had to start at the beginning or immediately
542        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
543        pcre_dfa_exec() could read past the end of the passed subject if there was
544        no match. To help with detecting such bugs (e.g. with valgrind), I modified
545        pcretest so that it places the subject at the end of its malloc-ed buffer.
546    
547    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
548        exec() might read past the end of the data buffer in UTF-8 mode.
549    
550    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
551        the data contained the byte 0x85 as part of a UTF-8 character within its
552        first line. This applied both to normal and DFA matching.
553    
554    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
555        /^[^d]*?$/8 failed to match "abc".
556    
557    16. Added a missing copyright notice to pcrecpp_internal.h.
558    
559    17. Make it more clear in the documentation that values returned from
560        pcre_exec() in ovector are byte offsets, not character counts.
561    
562    18. Tidied a few places to stop certain compilers from issuing warnings.
563    
564    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
565        supplied by Stefan Weber. I made a further small update for 7.8 because
566        there is a change of source arrangements: the pcre_searchfuncs.c module is
567        replaced by pcre_ucd.c.
568    
569    
570    Version 7.7 07-May-08
571    ---------------------
572    
573    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
574        a string to a long long, pretend we don't even have a long long." This is
575        done by checking for the strtoq, strtoll, and _strtoi64 functions.
576    
577    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
578        pre-7.6 versions, which defined a global no_arg variable instead of putting
579        it in the RE class. (See also #8 below.)
580    
581    3.  Remove a line of dead code, identified by coverity and reported by Nuno
582        Lopes.
583    
584    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
585    
586        (1) The include/exclude patterns were being applied to the whole pathnames
587            of files, instead of just to the final components.
588    
589        (2) If there was more than one level of directory, the subdirectories were
590            skipped unless they satisfied the include/exclude conditions. This is
591            inconsistent with GNU grep (and could even be seen as contrary to the
592            pcregrep specification - which I improved to make it absolutely clear).
593            The action now is always to scan all levels of directory, and just
594            apply the include/exclude patterns to regular files.
595    
596    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
597        --exclude_dir in the tests to avoid scanning .svn directories.
598    
599    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
600        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
601        doesn't support NULs in patterns.
602    
603    7.  Added some missing "const"s to declarations of static tables in
604        pcre_compile.c and pcre_dfa_exec.c.
605    
606    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
607        caused by fix #2  above. (Subsequently also a second patch to fix the
608        first patch. And a third patch - this was a messy problem.)
609    
610    9.  Applied Craig's patch to remove the use of push_back().
611    
612    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
613        matching function regexec().
614    
615    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
616        which, however, unlike Perl's \g{...}, are subroutine calls, not back
617        references. PCRE supports relative numbers with this syntax (I don't think
618        Oniguruma does).
619    
620    12. Previously, a group with a zero repeat such as (...){0} was completely
621        omitted from the compiled regex. However, this means that if the group
622        was called as a subroutine from elsewhere in the pattern, things went wrong
623        (an internal error was given). Such groups are now left in the compiled
624        pattern, with a new opcode that causes them to be skipped at execution
625        time.
626    
627    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
628        to the way PCRE behaves:
629    
630        (a) A lone ] character is dis-allowed (Perl treats it as data).
631    
632        (b) A back reference to an unmatched subpattern matches an empty string
633            (Perl fails the current match path).
634    
635        (c) A data ] in a character class must be notated as \] because if the
636            first data character in a class is ], it defines an empty class. (In
637            Perl it is not possible to have an empty class.) The empty class []
638            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
639            The negative empty class [^] matches any one character, independently
640            of the DOTALL setting.
641    
642    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
643        non-existent subpattern following a character class starting with ']' and
644        containing () gave an internal compiling error instead of "reference to
645        non-existent subpattern". Fortunately, when the pattern did exist, the
646        compiled code was correct. (When scanning forwards to check for the
647        existencd of the subpattern, it was treating the data ']' as terminating
648        the class, so got the count wrong. When actually compiling, the reference
649        was subsequently set up correctly.)
650    
651    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
652        it was being rejected as not supported by pcre_dfa_exec(), even though
653        other assertions are supported. I have made pcre_dfa_exec() support
654        (*FAIL).
655    
656    16. The implementation of 13c above involved the invention of a new opcode,
657        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
658        cannot be changed at match time, I realized I could make a small
659        improvement to matching performance by compiling OP_ALLANY instead of
660        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
661        on the OP_ANY path.
662    
663    17. Compiling pcretest on Windows with readline support failed without the
664        following two fixes: (1) Make the unistd.h include conditional on
665        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
666    
667    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
668        ncurses library to be included for pcretest when ReadLine support is
669        requested, but also to allow for it to be overridden. This patch came from
670        Daniel Bergström.
671    
672    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
673        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
674        any errors with the current Unicode tables. Thanks to Peter Kankowski for
675        spotting this.
676    
677    
678    Version 7.6 28-Jan-08
679    ---------------------
680    
681    1.  A character class containing a very large number of characters with
682        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
683        overflow.
684    
685    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
686        HAVE_LONG_LONG is not defined.
687    
688    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
689        bring them up to date and include new features. This patch includes:
690    
691        - Fixed PH's badly added libz and libbz2 support.
692        - Fixed a problem with static linking.
693        - Added pcredemo. [But later removed - see 7 below.]
694        - Fixed dftables problem and added an option.
695        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
696            HAVE_LONG_LONG.
697        - Added readline support for pcretest.
698        - Added an listing of the option settings after cmake has run.
699    
700    4.  A user submitted a patch to Makefile that makes it easy to create
701        "pcre.dll" under mingw when using Configure/Make. I added stuff to
702        Makefile.am that cause it to include this special target, without
703        affecting anything else. Note that the same mingw target plus all
704        the other distribution libraries and programs are now supported
705        when configuring with CMake (see 6 below) instead of with
706        Configure/Make.
707    
708    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
709        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
710        exported in the Windows port". It has not yet been confirmed that the patch
711        solves the problem, but it does no harm.
712    
713    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
714        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
715        with CMake, and also correct the comment about stack recursion.
716    
717    7.  Remove the automatic building of pcredemo from the ./configure system and
718        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
719        of a program that users should build themselves after PCRE is installed, so
720        building it automatically is not really right. What is more, it gave
721        trouble in some build environments.
722    
723    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
724    
725    
726    Version 7.5 10-Jan-08
727    ---------------------
728    
729    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
730        values in parens when parsing an RE using the C++ wrapper."
731    
732    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
733        Characters greater than 255 were excluded from the class instead of being
734        included.
735    
736    3.  The same bug as (2) above applied to negated POSIX classes such as
737        [:^space:].
738    
739    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
740        defined or documented. It seems to have been a typo for PCRE_STATIC, so
741        I have changed it.
742    
743    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
744        first named subpattern) and a construct such as (?&a) would reference the
745        first named subpattern whose name started with "a" (in other words, the
746        length check was missing). Both these problems are fixed. "Subpattern name
747        expected" is now given for (?&) (a zero-length name), and this patch also
748        makes it give the same error for \k'' (previously it complained that that
749        was a reference to a non-existent subpattern).
750    
751    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
752        this is right because (?- can be followed by option settings as well as by
753        digits. I have, however, made the messages clearer.
754    
755    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
756        than the number used in the conditional) now cause a compile-time error.
757        This is actually not compatible with Perl, which accepts such patterns, but
758        treats the conditional as always being FALSE (as PCRE used to), but it
759        seems to me that giving a diagnostic is better.
760    
761    8.  Change "alphameric" to the more common word "alphanumeric" in comments
762        and messages.
763    
764    9.  Fix two occurrences of "backslash" in comments that should have been
765        "backspace".
766    
767    10. Remove two redundant lines of code that can never be obeyed (their function
768        was moved elsewhere).
769    
770    11. The program that makes PCRE's Unicode character property table had a bug
771        which caused it to generate incorrect table entries for sequences of
772        characters that have the same character type, but are in different scripts.
773        It amalgamated them into a single range, with the script of the first of
774        them. In other words, some characters were in the wrong script. There were
775        thirteen such cases, affecting characters in the following ranges:
776    
777          U+002b0 - U+002c1
778          U+0060c - U+0060d
779          U+0061e - U+00612
780          U+0064b - U+0065e
781          U+0074d - U+0076d
782          U+01800 - U+01805
783          U+01d00 - U+01d77
784          U+01d9b - U+01dbf
785          U+0200b - U+0200f
786          U+030fc - U+030fe
787          U+03260 - U+0327f
788          U+0fb46 - U+0fbb1
789          U+10450 - U+1049d
790    
791    12. The -o option (show only the matching part of a line) for pcregrep was not
792        compatible with GNU grep in that, if there was more than one match in a
793        line, it showed only the first of them. It now behaves in the same way as
794        GNU grep.
795    
796    13. If the -o and -v options were combined for pcregrep, it printed a blank
797        line for every non-matching line. GNU grep prints nothing, and pcregrep now
798        does the same. The return code can be used to tell if there were any
799        non-matching lines.
800    
801    14. Added --file-offsets and --line-offsets to pcregrep.
802    
803    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
804        infinitely looping recursion. The bug was that positive lookaheads were not
805        being skipped when checking for a possible empty match (negative lookaheads
806        and both kinds of lookbehind were skipped).
807    
808    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
809        inclusion of <windows.h> to before rather than after the definition of
810        INVALID_FILE_ATTRIBUTES (patch from David Byron).
811    
812    17. Specifying a possessive quantifier with a specific limit for a Unicode
813        character property caused pcre_compile() to compile bad code, which led at
814        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
815        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
816        caused the error; without that there was no problem.
817    
818    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
819    
820    19. Added --enable-pcretest-libreadline.
821    
822    20. In pcrecpp.cc, the variable 'count' was incremented twice in
823        RE::GlobalReplace(). As a result, the number of replacements returned was
824        double what it should be. I removed one of the increments, but Craig sent a
825        later patch that removed the other one (the right fix) and added unit tests
826        that check the return values (which was not done before).
827    
828    21. Several CMake things:
829    
830        (1) Arranged that, when cmake is used on Unix, the libraries end up with
831            the names libpcre and libpcreposix, not just pcre and pcreposix.
832    
833        (2) The above change means that pcretest and pcregrep are now correctly
834            linked with the newly-built libraries, not previously installed ones.
835    
836        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
837    
838    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
839        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
840        UTF-8 newline character). The key issue is that the pattern starts .*;
841        this means that the match must be either at the beginning, or after a
842        newline. The bug was in the code for advancing after a failed match and
843        checking that the new position followed a newline. It was not taking
844        account of UTF-8 characters correctly.
845    
846    23. PCRE was behaving differently from Perl in the way it recognized POSIX
847        character classes. PCRE was not treating the sequence [:...:] as a
848        character class unless the ... were all letters. Perl, however, seems to
849        allow any characters between [: and :], though of course it rejects as
850        unknown any "names" that contain non-letters, because all the known class
851        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
852        for example, whereas PCRE did not - it did not recognize a POSIX character
853        class. This seemed a bit dangerous, so the code has been changed to be
854        closer to Perl. The behaviour is not identical to Perl, because PCRE will
855        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
856        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
857        Perl does, and where it didn't before.
858    
859    24. Rewrite so as to remove the single use of %n from pcregrep because in some
860        Windows environments %n is disabled by default.
861    
862    
863    Version 7.4 21-Sep-07
864    ---------------------
865    
866    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
867        means that a class such as [\s] counted as "explicit reference to CR or
868        LF". That isn't really right - the whole point of the change was to try to
869        help when there was an actual mention of one of the two characters. So now
870        the change happens only if \r or \n (or a literal CR or LF) character is
871        encountered.
872    
873    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
874        of both had grown to the point where there were only 3 bits left.
875        Fortunately, there was spare space in the data structure, and so I have
876        moved the internal flags into a new 16-bit field to free up more option
877        bits.
878    
879    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
880        but did not set the internal JCHANGED flag - either of these is enough to
881        control the way the "get" function works - but the PCRE_INFO_JCHANGED
882        facility is supposed to tell if (?J) was ever used, so now (?J) at the
883        start sets both bits.
884    
885    4.  Added options (at build time, compile time, exec time) to change \R from
886        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
887    
888    5.  doc/pcresyntax.html was missing from the distribution.
889    
890    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
891        compatibility, even though it is no longer used.
892    
893    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
894        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
895        windows.h file is present (where different names are used). [This was
896        reversed later after testing - see 16 below.]
897    
898    8.  Changed all #include <config.h> to #include "config.h". There were also
899        some further <pcre.h> cases that I changed to "pcre.h".
900    
901    9.  When pcregrep was used with the --colour option, it missed the line ending
902        sequence off the lines that it output.
903    
904    10. It was pointed out to me that arrays of string pointers cause lots of
905        relocations when a shared library is dynamically loaded. A technique of
906        using a single long string with a table of offsets can drastically reduce
907        these. I have refactored PCRE in four places to do this. The result is
908        dramatic:
909    
910          Originally:                          290
911          After changing UCP table:            187
912          After changing error message table:   43
913          After changing table of "verbs"       36
914          After changing table of Posix names   22
915    
916        Thanks to the folks working on Gregex for glib for this insight.
917    
918    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
919        unicode-properties was also set.
920    
921    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
922    
923    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
924        checked only for CRLF.
925    
926    14. Added casts to pcretest.c to avoid compiler warnings.
927    
928    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
929    
930    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
931        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
932        entirely. This removes changes made in 7 above.
933    
934    17. The CMake files have been updated, and there is now more information about
935        building with CMake in the NON-UNIX-USE document.
936    
937    
938    Version 7.3 28-Aug-07
939    ---------------------
940    
941     1. In the rejigging of the build system that eventually resulted in 7.1, the
942        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
943        brackets there is not right, since it causes compilers to look for an
944        installed pcre.h, not the version that is in the source that is being
945        compiled (which of course may be different). I have changed it back to:
946    
947          #include "pcre.h"
948    
949        I have a vague recollection that the change was concerned with compiling in
950        different directories, but in the new build system, that is taken care of
951        by the VPATH setting the Makefile.
952    
953     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
954        when the subject happened to end in the byte 0x85 (e.g. if the last
955        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
956        characters but of course it shouldn't be taken as a newline when it is part
957        of another character. The bug was that, for an unlimited repeat of . in
958        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
959        characters when looking for a newline.
960    
961     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
962    
963     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
964        in debug output.
965    
966     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
967        long printing in the pcrecpp unittest when running under MinGW.
968    
969     6. ESC_K was left out of the EBCDIC table.
970    
971     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
972        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
973        limit also applies to "virtual nesting" when a pattern is recursive, and in
974        this case 1000 isn't so big. I have been able to remove this limit at the
975        expense of backing off one optimization in certain circumstances. Normally,
976        when pcre_exec() would call its internal match() function recursively and
977        immediately return the result unconditionally, it uses a "tail recursion"
978        feature to save stack. However, when a subpattern that can match an empty
979        string has an unlimited repetition quantifier, it no longer makes this
980        optimization. That gives it a stack frame in which to save the data for
981        checking that an empty string has been matched. Previously this was taken
982        from the 1000-entry workspace that had been reserved. So now there is no
983        explicit limit, but more stack is used.
984    
985     8. Applied Daniel's patches to solve problems with the import/export magic
986        syntax that is required for Windows, and which was going wrong for the
987        pcreposix and pcrecpp parts of the library. These were overlooked when this
988        problem was solved for the main library.
989    
990     9. There were some crude static tests to avoid integer overflow when computing
991        the size of patterns that contain repeated groups with explicit upper
992        limits. As the maximum quantifier is 65535, the maximum group length was
993        set at 30,000 so that the product of these two numbers did not overflow a
994        32-bit integer. However, it turns out that people want to use groups that
995        are longer than 30,000 bytes (though not repeat them that many times).
996        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
997        made it possible to implement the integer overflow checks in a much more
998        dynamic way, which I have now done. The artificial limitation on group
999        length has been removed - we now have only the limit on the total length of
1000        the compiled pattern, which depends on the LINK_SIZE setting.
1001    
1002    10. Fixed a bug in the documentation for get/copy named substring when
1003        duplicate names are permitted. If none of the named substrings are set, the
1004        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1005        empty string.
1006    
1007    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1008        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1009        because the ] is interpreted as the first data character and the
1010        terminating ] is not found. PCRE has been made compatible with Perl in this
1011        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1012        cause memory overwriting.
1013    
1014    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1015        string has been matched (to stop an infinite loop). It was not recognizing
1016        a conditional subpattern that could match an empty string if that
1017        subpattern was within another subpattern. For example, it looped when
1018        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1019        condition was not nested. This bug has been fixed.
1020    
1021    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1022        past the start of the subject in the presence of bytes with the top bit
1023        set, for example "\x8aBCD".
1024    
1025    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1026        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1027    
1028    14. Optimized (?!) to (*FAIL).
1029    
1030    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1031        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1032        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1033        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1034        does: it's just the validity check that is more restrictive.
1035    
1036    16. Inserted checks for integer overflows during escape sequence (backslash)
1037        processing, and also fixed erroneous offset values for syntax errors during
1038        backslash processing.
1039    
1040    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1041        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1042    
1043    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1044        caused an overrun.
1045    
1046    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1047        something other than just ASCII characters) inside a group that had an
1048        unlimited repeat caused a loop at compile time (while checking to see
1049        whether the group could match an empty string).
1050    
1051    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1052        [\P{Any}] did so. (Error in the code for printing property names.)
1053    
1054    21. An orphan \E inside a character class could cause a crash.
1055    
1056    22. A repeated capturing bracket such as (A)? could cause a wild memory
1057        reference during compilation.
1058    
1059    23. There are several functions in pcre_compile() that scan along a compiled
1060        expression for various reasons (e.g. to see if it's fixed length for look
1061        behind). There were bugs in these functions when a repeated \p or \P was
1062        present in the pattern. These operators have additional parameters compared
1063        with \d, etc, and these were not being taken into account when moving along
1064        the compiled data. Specifically:
1065    
1066        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1067            length.
1068    
1069        (b) An item such as \pL+ within a repeated group could cause crashes or
1070            loops.
1071    
1072        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1073            "reference to non-existent subpattern" error.
1074    
1075        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1076    
1077    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1078        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1079    
1080    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1081    
1082    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1083        character were causing crashes (broken optimization).
1084    
1085    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1086        \p or \P) caused a compile-time loop.
1087    
1088    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1089        break. For example, the unstudied pattern [\r\n]A does not match the string
1090        "\r\nA" because change 7.0/46 below moves the current point on by two
1091        characters after failing to match at the start. However, the pattern \nA
1092        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1093        the same is true. There doesn't seem any very clean way out of this, but
1094        what I have chosen to do makes the common cases work: PCRE now takes note
1095        of whether there can be an explicit match for \r or \n anywhere in the
1096        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1097        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1098        pattern has explicit CR or LF references.
1099    
1100    29. Added (*CR) etc for changing newline setting at start of pattern.
1101    
1102    
1103    Version 7.2 19-Jun-07
1104    ---------------------
1105    
1106     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1107        which is apparently normally available under Windows.
1108    
1109     2. Re-jig the pcregrep tests with different newline settings in an attempt
1110        to make them independent of the local environment's newline setting.
1111    
1112     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1113    
1114     4. Some of the "internals" tests were previously cut out when the link size
1115        was not 2, because the output contained actual offsets. The recent new
1116        "Z" feature of pcretest means that these can be cut out, making the tests
1117        usable with all link sizes.
1118    
1119     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1120        stack recursion. This gives a massive performance boost under BSD, but just
1121        a small improvement under Linux. However, it saves one field in the frame
1122        in all cases.
1123    
1124     6. Added more features from the forthcoming Perl 5.10:
1125    
1126        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1127            recursion call. It refers to the nth most recently opened parentheses.
1128    
1129        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1130            to be opened parentheses.
1131    
1132        (c) Conditions that refer to capturing parentheses can be specified
1133            relatively, for example, (?(-2)... or (?(+3)...
1134    
1135        (d) \K resets the start of the current match so that everything before
1136            is not part of it.
1137    
1138        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1139    
1140        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1141            reference syntax.
1142    
1143        (g) (?| introduces a group in which the numbering of parentheses in each
1144            alternative starts with the same number.
1145    
1146        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1147    
1148     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1149        PCRE_INFO_JCHANGED.
1150    
1151     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1152        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1153        for detecting groups that can match an empty string.
1154    
1155     9. A pattern with a very large number of alternatives (more than several
1156        hundred) was running out of internal workspace during the pre-compile
1157        phase, where pcre_compile() figures out how much memory will be needed. A
1158        bit of new cunning has reduced the workspace needed for groups with
1159        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1160        workspace instead of running out of the 4096 that are available.
1161    
1162    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1163    
1164    11. Applied patch from Google to remove an optimization that didn't quite work.
1165        The report of the bug said:
1166    
1167          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1168          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1169          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1170    
1171    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1172        it matched the wrong number of bytes.
1173    
1174    
1175    Version 7.1 24-Apr-07
1176    ---------------------
1177    
1178     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1179        that is more "standard", making use of automake and other Autotools. There
1180        is some re-arrangement of the files and adjustment of comments consequent
1181        on this.
1182    
1183     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1184        for recursive directory scanning broke on some systems because the files
1185        are not scanned in any specific order and on different systems the order
1186        was different. A call to "sort" has been inserted into RunGrepTest for the
1187        approprate test as a short-term fix. In the longer term there may be an
1188        alternative.
1189    
1190     3. I had an email from Eric Raymond about problems translating some of PCRE's
1191        man pages to HTML (despite the fact that I distribute HTML pages, some
1192        people do their own conversions for various reasons). The problems
1193        concerned the use of low-level troff macros .br and .in. I have therefore
1194        removed all such uses from the man pages (some were redundant, some could
1195        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1196        HTML has been updated to handle .nf/.fi and to complain if it encounters
1197        .br or .in.
1198    
1199     4. Updated comments in configure.ac that get placed in config.h.in and also
1200        arranged for config.h to be included in the distribution, with the name
1201        config.h.generic, for the benefit of those who have to compile without
1202        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1203    
1204     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1205        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1206        makevp.bat for the current PCRE, using the additional files
1207        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1208    
1209     6. A Windows user reported a minor discrepancy with test 2, which turned out
1210        to be caused by a trailing space on an input line that had got lost in his
1211        copy. The trailing space was an accident, so I've just removed it.
1212    
1213     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1214        that is needed.
1215    
1216     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1217        as "const" (a) because they are and (b) because it helps the PHP
1218        maintainers who have recently made a script to detect big data structures
1219        in the php code that should be moved to the .rodata section. I remembered
1220        to update Builducptable as well, so it won't revert if ucptable.h is ever
1221        re-created.
1222    
1223     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1224        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1225        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1226        support is not required. This saves 1.5-2K of code, which is important in
1227        some applications.
1228    
1229        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1230        so as not to refer to the tables, even though these functions will never be
1231        called when UTF-8 support is disabled. Otherwise there are problems with a
1232        shared library.
1233    
1234    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1235    
1236        (a) It was defining its arguments as char * instead of void *.
1237    
1238        (b) It was assuming that all moves were upwards in memory; this was true
1239            a long time ago when I wrote it, but is no longer the case.
1240    
1241        The emulated memove() is provided for those environments that have neither
1242        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1243        is clearly not the case, as these two bugs were recently reported.
1244    
1245    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1246        and Detrail to create the HTML documentation, the .txt form of the man
1247        pages, and it removes trailing spaces from listed files. It also creates
1248        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1249        case, it wraps all the #defines with #ifndefs. This script should be run
1250        before "make dist".
1251    
1252    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1253        with Unicode property support.
1254    
1255        (a) For a maximizing quantifier, if the two different cases of the
1256            character were of different lengths in their UTF-8 codings (there are
1257            some cases like this - I found 11), and the matching function had to
1258            back up over a mixture of the two cases, it incorrectly assumed they
1259            were both the same length.
1260    
1261        (b) When PCRE was configured to use the heap rather than the stack for
1262            recursion during matching, it was not correctly preserving the data for
1263            the other case of a UTF-8 character when checking ahead for a match
1264            while processing a minimizing repeat. If the check also involved
1265            matching a wide character, but failed, corruption could cause an
1266            erroneous result when trying to check for a repeat of the original
1267            character.
1268    
1269    13. Some tidying changes to the testing mechanism:
1270    
1271        (a) The RunTest script now detects the internal link size and whether there
1272            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1273            values substituted by "configure". (The RunGrepTest script already did
1274            this for UTF-8.) The configure.ac script no longer substitutes the
1275            relevant variables.
1276    
1277        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1278            with length and offset values. This means that the output is different
1279            for different internal link sizes. Test 2 is skipped for link sizes
1280            other than 2 because of this, bypassing the problem. Unfortunately,
1281            there was also a test in test 3 (the locale tests) that used /B and
1282            failed for link sizes other than 2. Rather than cut the whole test out,
1283            I have added a new /Z option to pcretest that replaces the length and
1284            offset values with spaces. This is now used to make test 3 independent
1285            of link size. (Test 2 will be tidied up later.)
1286    
1287    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1288        segmentation fault instead of returning the appropriate error message.
1289    
1290    15. In multiline mode when the newline sequence was set to "any", the pattern
1291        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1292        This doesn't seem right; it now treats the CRLF combination as the line
1293        ending, and so does not match in that case. It's only a pattern such as ^$
1294        that would hit this one: something like ^ABC$ would have failed after \r
1295        and then tried again after \r\n.
1296    
1297    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1298        in an attempt to make files that differ only in their line terminators
1299        compare equal. This works on Linux.
1300    
1301    17. Under certain error circumstances pcregrep might try to free random memory
1302        as it exited. This is now fixed, thanks to valgrind.
1303    
1304    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1305        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1306        was because its rules for how to advance for /g after matching an empty
1307        string at the end of a line did not allow for this case. They now check for
1308        it specially.
1309    
1310    20. pcretest is supposed to handle patterns and data of any length, by
1311        extending its buffers when necessary. It was getting this wrong when the
1312        buffer for a data line had to be extended.
1313    
1314    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1315        CRLF as a newline sequence.
1316    
1317    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1318        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1319        I have nevertheless tidied it up.
1320    
1321    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1322    
1323    24. Added a man page for pcre-config.
1324    
1325    
1326    Version 7.0 19-Dec-06
1327    ---------------------
1328    
1329     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1330        moving to gcc 4.1.1.
1331    
1332     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1333        sys/time.h, which is documented as needed for this function. It doesn't
1334        seem to matter on Linux, but it showed up on some releases of OS X.
1335    
1336     3. It seems that there are systems where bytes whose values are greater than
1337        127 match isprint() in the "C" locale. The "C" locale should be the
1338        default when a C program starts up. In most systems, only ASCII printing
1339        characters match isprint(). This difference caused the output from pcretest
1340        to vary, making some of the tests fail. I have changed pcretest so that:
1341    
1342        (a) When it is outputting text in the compiled version of a pattern, bytes
1343            other than 32-126 are always shown as hex escapes.
1344    
1345        (b) When it is outputting text that is a matched part of a subject string,
1346            it does the same, unless a different locale has been set for the match
1347            (using the /L modifier). In this case, it uses isprint() to decide.
1348    
1349     4. Fixed a major bug that caused incorrect computation of the amount of memory
1350        required for a compiled pattern when options that changed within the
1351        pattern affected the logic of the preliminary scan that determines the
1352        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1353        that the computed length was too small. The symptoms of this bug were
1354        either the PCRE error "internal error: code overflow" from pcre_compile(),
1355        or a glibc crash with a message such as "pcretest: free(): invalid next
1356        size (fast)". Examples of patterns that provoked this bug (shown in
1357        pcretest format) are:
1358    
1359          /(?-x: )/x
1360          /(?x)(?-x: \s*#\s*)/
1361          /((?i)[\x{c0}])/8
1362          /(?i:[\x{c0}])/8
1363    
1364        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1365        is now done differently.
1366    
1367     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1368        wrapper classes; (b) implement a new function in the C++ scanner that is
1369        more efficient than the old way of doing things because it avoids levels of
1370        recursion in the regex matching; (c) add a paragraph to the documentation
1371        for the FullMatch() function.
1372    
1373     6. The escape sequence \n was being treated as whatever was defined as
1374        "newline". Not only was this contrary to the documentation, which states
1375        that \n is character 10 (hex 0A), but it also went horribly wrong when
1376        "newline" was defined as CRLF. This has been fixed.
1377    
1378     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1379        was being set to -1 for the "end of line" case (supposedly a value that no
1380        character can have). Though this value is never used (the check for end of
1381        line is "zero bytes in current character"), it caused compiler complaints.
1382        I've changed it to 0xffffffff.
1383    
1384     8. In pcre_version.c, the version string was being built by a sequence of
1385        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1386        string (as it is for production releases) called a macro with an empty
1387        argument. The C standard says the result of this is undefined. The gcc
1388        compiler treats it as an empty string (which was what was wanted) but it is
1389        reported that Visual C gives an error. The source has been hacked around to
1390        avoid this problem.
1391    
1392     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1393        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1394        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1395        of them did).
1396    
1397    10. Originally, pcretest opened its input and output without "b"; then I was
1398        told that "b" was needed in some environments, so it was added for release
1399        5.0 to both the input and output. (It makes no difference on Unix-like
1400        systems.) Later I was told that it is wrong for the input on Windows. I've
1401        now abstracted the modes into two macros, to make it easier to fiddle with
1402        them, and removed "b" from the input mode under Windows.
1403    
1404    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1405    
1406    12. Added -help and --help to pcretest as an official way of being reminded
1407        of the options.
1408    
1409    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1410        and pcrecpp.cc because they annoy compilers at high warning levels.
1411    
1412    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1413    
1414    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1415        scripts are not C programs :-) and which was not noticed because it works
1416        on Linux.
1417    
1418    16. pcretest is supposed to handle any length of pattern and data line (as one
1419        line or as a continued sequence of lines) by extending its input buffer if
1420        necessary. This feature was broken for very long pattern lines, leading to
1421        a string of junk being passed to pcre_compile() if the pattern was longer
1422        than about 50K.
1423    
1424    17. I have done a major re-factoring of the way pcre_compile() computes the
1425        amount of memory needed for a compiled pattern. Previously, there was code
1426        that made a preliminary scan of the pattern in order to do this. That was
1427        OK when PCRE was new, but as the facilities have expanded, it has become
1428        harder and harder to keep it in step with the real compile phase, and there
1429        have been a number of bugs (see for example, 4 above). I have now found a
1430        cunning way of running the real compile function in a "fake" mode that
1431        enables it to compute how much memory it would need, while actually only
1432        ever using a few hundred bytes of working memory and without too many
1433        tests of the mode. This should make future maintenance and development
1434        easier. A side effect of this work is that the limit of 200 on the nesting
1435        depth of parentheses has been removed (though this was never a serious
1436        limitation, I suspect). However, there is a downside: pcre_compile() now
1437        runs more slowly than before (30% or more, depending on the pattern). I
1438        hope this isn't a big issue. There is no effect on runtime performance.
1439    
1440    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1441        newline (only possible for the last line of a file) and it was a
1442        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1443    
1444    19. Added additional timing features to pcretest. (1) The -tm option now times
1445        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1446        separate command line item, by a number that specifies the number of
1447        repeats to use when timing. The default is 50000; this gives better
1448        precision, but takes uncomfortably long for very large patterns.
1449    
1450    20. Extended pcre_study() to be more clever in cases where a branch of a
1451        subpattern has no definite first character. For example, (a*|b*)[cd] would
1452        previously give no result from pcre_study(). Now it recognizes that the
1453        first character must be a, b, c, or d.
1454    
1455    21. There was an incorrect error "recursive call could loop indefinitely" if
1456        a subpattern (or the entire pattern) that was being tested for matching an
1457        empty string contained only one non-empty item after a nested subpattern.
1458        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1459        incorrectly, because the \d was being skipped in the check.
1460    
1461    22. The pcretest program now has a new pattern option /B and a command line
1462        option -b, which is equivalent to adding /B to every pattern. This causes
1463        it to show the compiled bytecode, without the additional information that
1464        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1465        is the same as /B/I).
1466    
1467    23. A new optimization is now able automatically to treat some sequences such
1468        as a*b as a*+b. More specifically, if something simple (such as a character
1469        or a simple class like \d) has an unlimited quantifier, and is followed by
1470        something that cannot possibly match the quantified thing, the quantifier
1471        is automatically "possessified".
1472    
1473    24. A recursive reference to a subpattern whose number was greater than 39
1474        went wrong under certain circumstances in UTF-8 mode. This bug could also
1475        have affected the operation of pcre_study().
1476    
1477    25. Realized that a little bit of performance could be had by replacing
1478        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1479    
1480    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1481    
1482    27. Possessive quantifiers such as a++ were previously implemented by turning
1483        them into atomic groups such as ($>a+). Now they have their own opcodes,
1484        which improves performance. This includes the automatically created ones
1485        from 23 above.
1486    
1487    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1488        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1489        the first matched character to be a colon. This applied both to named and
1490        numbered groups.
1491    
1492    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1493    
1494    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1495        building PCRE on Windows easier, so I have included it in the distribution.
1496    
1497    31. There is now a check in pcretest against a ridiculously large number being
1498        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1499        loop, the loop is abandoned.
1500    
1501    32. Forward references to subpatterns in conditions such as (?(2)...) where
1502        subpattern 2 is defined later cause pcre_compile() to search forwards in
1503        the pattern for the relevant set of parentheses. This search went wrong
1504        when there were unescaped parentheses in a character class, parentheses
1505        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1506    
1507    33. "Subroutine" calls and backreferences were previously restricted to
1508        referencing subpatterns earlier in the regex. This restriction has now
1509        been removed.
1510    
1511    34. Added a number of extra features that are going to be in Perl 5.10. On the
1512        whole, these are just syntactic alternatives for features that PCRE had
1513        previously implemented using the Python syntax or my own invention. The
1514        other formats are all retained for compatibility.
1515    
1516        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1517            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1518            also .NET compatible.
1519    
1520        (b) A recursion or subroutine call to a named group can now be defined as
1521            (?&name) as well as (?P>name).
1522    
1523        (c) A backreference to a named group can now be defined as \k<name> or
1524            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1525            5.10, are also .NET compatible.
1526    
1527        (d) A conditional reference to a named group can now use the syntax
1528            (?(<name>) or (?('name') as well as (?(name).
1529    
1530        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1531            groups (named and numbered) that are never evaluated inline, but can be
1532            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1533            is always false. There may be only one alternative in such a group.
1534    
1535        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1536            as the simple (?(R). The condition is true only if the most recent
1537            recursion is that of the given number or name. It does not search out
1538            through the entire recursion stack.
1539    
1540        (g) The escape \gN or \g{N} has been added, where N is a positive or
1541            negative number, specifying an absolute or relative reference.
1542    
1543    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1544        some "unreachable code" warnings.
1545    
1546    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1547        things, this adds five new scripts.
1548    
1549    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1550        There were also incompatibilities regarding the handling of \Q..\E inside
1551        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1552        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1553    
1554    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1555        matches an empty string, and forcibly breaks the loop. There were bugs in
1556        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1557        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1558        separate and independent bugs (that affected different cases) have been
1559        fixed.
1560    
1561    39. Refactored the code to abolish the use of different opcodes for small
1562        capturing bracket numbers. This is a tidy that I avoided doing when I
1563        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1564        The new approach is not only tidier, it makes it possible to reduce the
1565        memory needed to fix the previous bug (38).
1566    
1567    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1568        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1569        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1570        mode.
1571    
1572    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1573        report.
1574    
1575    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1576        copy construction and assignment in the C++ wrapper.
1577    
1578    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1579        couple of bugs that could have given wrong results in the "--newline=crlf"
1580        case.
1581    
1582    44. Added a number of casts and did some reorganization of signed/unsigned int
1583        variables following suggestions from Dair Grant. Also renamed the variable
1584        "this" as "item" because it is a C++ keyword.
1585    
1586    45. Arranged for dftables to add
1587    
1588          #include "pcre_internal.h"
1589    
1590        to pcre_chartables.c because without it, gcc 4.x may remove the array
1591        definition from the final binary if PCRE is built into a static library and
1592        dead code stripping is activated.
1593    
1594    46. For an unanchored pattern, if a match attempt fails at the start of a
1595        newline sequence, and the newline setting is CRLF or ANY, and the next two
1596        characters are CRLF, advance by two characters instead of one.
1597    
1598    
1599    Version 6.7 04-Jul-06
1600    ---------------------
1601    
1602     1. In order to handle tests when input lines are enormously long, pcretest has
1603        been re-factored so that it automatically extends its buffers when
1604        necessary. The code is crude, but this _is_ just a test program. The
1605        default size has been increased from 32K to 50K.
1606    
1607     2. The code in pcre_study() was using the value of the re argument before
1608        testing it for NULL. (Of course, in any sensible call of the function, it
1609        won't be NULL.)
1610    
1611     3. The memmove() emulation function in pcre_internal.h, which is used on
1612        systems that lack both memmove() and bcopy() - that is, hardly ever -
1613        was missing a "static" storage class specifier.
1614    
1615     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1616        containing an extended class (one that cannot be represented by a bitmap
1617        because it contains high-valued characters or Unicode property items, e.g.
1618        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1619        pattern, but PCRE should not loop if you do not (it no longer does).
1620        [Detail: two cases were found: (a) a repeated subpattern containing an
1621        extended class; (b) a recursive reference to a subpattern that followed a
1622        previous extended class. It wasn't skipping over the extended class
1623        correctly when UTF-8 mode was not set.]
1624    
1625     5. A negated single-character class was not being recognized as fixed-length
1626        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1627        compile error "lookbehind assertion is not fixed length".
1628    
1629     6. The RunPerlTest auxiliary script was showing an unexpected difference
1630        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1631        write a Perl script that can interpret lines of an input file either as
1632        byte characters or as UTF-8, which is what "perltest" was being required to
1633        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1634        can't do is switch easily at run time between having the "use utf8;" pragma
1635        or not. In the end, I fudged it by using the RunPerlTest script to insert
1636        "use utf8;" explicitly for the UTF-8 tests.
1637    
1638     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1639        the end of the subject string, contrary to the documentation and to what
1640        Perl does. This was true of both matching functions. Now it matches only at
1641        the start of the subject and immediately after *internal* newlines.
1642    
1643     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1644        a pointer to an int instead of a pointer to an unsigned long int. This
1645        caused problems on 64-bit systems.
1646    
1647     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1648        instance of the 'standard' template library not being so standard".
1649    
1650    10. There was no check on the number of named subpatterns nor the maximum
1651        length of a subpattern name. The product of these values is used to compute
1652        the size of the memory block for a compiled pattern. By supplying a very
1653        long subpattern name and a large number of named subpatterns, the size
1654        computation could be caused to overflow. This is now prevented by limiting
1655        the length of names to 32 characters, and the number of named subpatterns
1656        to 10,000.
1657    
1658    11. Subpatterns that are repeated with specific counts have to be replicated in
1659        the compiled pattern. The size of memory for this was computed from the
1660        length of the subpattern and the repeat count. The latter is limited to
1661        65535, but there was no limit on the former, meaning that integer overflow
1662        could in principle occur. The compiled length of a repeated subpattern is
1663        now limited to 30,000 bytes in order to prevent this.
1664    
1665    12. Added the optional facility to have named substrings with the same name.
1666    
1667    13. Added the ability to use a named substring as a condition, using the
1668        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1669        are numbers (not recommended). Forward references are permitted.
1670    
1671    14. Added forward references in named backreferences (if you see what I mean).
1672    
1673    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1674        pattern could run off the end of the subject. For example, the pattern
1675        "(?s)(.{1,5})"8 did this with the subject "ab".
1676    
1677    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1678        PCRE_CASELESS was set when matching characters that were quantified with ?
1679        or *.
1680    
1681    17. A character class other than a single negated character that had a minimum
1682        but no maximum quantifier - for example [ab]{6,} - was not handled
1683        correctly by pce_dfa_exec(). It would match only one character.
1684    
1685    18. A valid (though odd) pattern that looked like a POSIX character
1686        class but used an invalid character after [ (for example [[,abc,]]) caused
1687        pcre_compile() to give the error "Failed: internal error: code overflow" or
1688        in some cases to crash with a glibc free() error. This could even happen if
1689        the pattern terminated after [[ but there just happened to be a sequence of
1690        letters, a binary zero, and a closing ] in the memory that followed.
1691    
1692    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1693        over the years. Originally (before any Unicode support), just the bottom 8
1694        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1695        output from "man perlunicode" includes this:
1696    
1697          The regular expression compiler produces polymorphic opcodes.  That
1698          is, the pattern adapts to the data and automatically switches to
1699          the Unicode character scheme when presented with Unicode data--or
1700          instead uses a traditional byte scheme when presented with byte
1701          data.
1702    
1703        Sadly, a wide octal escape does not cause a switch, and in a string with
1704        no other multibyte characters, these octal escapes are treated as before.
1705        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1706        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1707        Unicode string.
1708    
1709        I have not perpetrated such confusion in PCRE. Up till now, it took just
1710        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1711        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1712        translate to the appropriate multibyte character.
1713    
1714    29. Applied some refactoring to reduce the number of warnings from Microsoft
1715        and Borland compilers. This has included removing the fudge introduced
1716        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1717        a warning about an unused variable.
1718    
1719    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1720        characters since release 4.0, because Perl (from release 5.004) does not.
1721        [Or at least, is documented not to: some releases seem to be in conflict
1722        with the documentation.] However, when a pattern was studied with
1723        pcre_study() and all its branches started with \s, PCRE still included VT
1724        as a possible starting character. Of course, this did no harm; it just
1725        caused an unnecessary match attempt.
1726    
1727    22. Removed a now-redundant internal flag bit that recorded the fact that case
1728        dependency changed within the pattern. This was once needed for "required
1729        byte" processing, but is no longer used. This recovers a now-scarce options
1730        bit. Also moved the least significant internal flag bit to the most-
1731        significant bit of the word, which was not previously used (hangover from
1732        the days when it was an int rather than a uint) to free up another bit for
1733        the future.
1734    
1735    23. Added support for CRLF line endings as well as CR and LF. As well as the
1736        default being selectable at build time, it can now be changed at runtime
1737        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1738        specify that it is scanning data with non-default line endings.
1739    
1740    24. Changed the definition of CXXLINK to make it agree with the definition of
1741        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1742    
1743    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1744        recursions. This makes a big different to stack usage for some patterns.
1745    
1746    26. If a subpattern containing a named recursion or subroutine reference such
1747        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1748        the space required for the compiled pattern went wrong and gave too small a
1749        value. Depending on the environment, this could lead to "Failed: internal
1750        error: code overflow at offset 49" or "glibc detected double free or
1751        corruption" errors.
1752    
1753    27. Applied patches from Google (a) to support the new newline modes and (b) to
1754        advance over multibyte UTF-8 characters in GlobalReplace.
1755    
1756    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1757        difference for some implementation of PCRE in some Windows version.
1758    
1759    29. Added some extra testing facilities to pcretest:
1760    
1761        \q<number>   in a data line sets the "match limit" value
1762        \Q<number>   in a data line sets the "match recursion limt" value
1763        -S <number>  sets the stack size, where <number> is in megabytes
1764    
1765        The -S option isn't available for Windows.
1766    
1767    
1768    Version 6.6 06-Feb-06
1769    ---------------------
1770    
1771     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1772        in pcreposix.h. I have copied the definition from pcre.h.
1773    
1774     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1775        because pcre.h is no longer a built file.
1776    
1777     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1778        not normally included in the compiled code.
1779    
1780    
1781    Version 6.5 01-Feb-06
1782    ---------------------
1783    
1784     1. When using the partial match feature with pcre_dfa_exec(), it was not
1785        anchoring the second and subsequent partial matches at the new starting
1786        point. This could lead to incorrect results. For example, with the pattern
1787        /1234/, partially matching against "123" and then "a4" gave a match.
1788    
1789     2. Changes to pcregrep:
1790    
1791        (a) All non-match returns from pcre_exec() were being treated as failures
1792            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1793            error message is output. Some extra information is given for the
1794            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1795            probably the only errors that are likely to be caused by users (by
1796            specifying a regex that has nested indefinite repeats, for instance).
1797            If there are more than 20 of these errors, pcregrep is abandoned.
1798    
1799        (b) A binary zero was treated as data while matching, but terminated the
1800            output line if it was written out. This has been fixed: binary zeroes
1801            are now no different to any other data bytes.
1802    
1803        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1804            used to set a locale for matching. The --locale=xxxx long option has
1805            been added (no short equivalent) to specify a locale explicitly on the
1806            pcregrep command, overriding the environment variables.
1807    
1808        (d) When -B was used with -n, some line numbers in the output were one less
1809            than they should have been.
1810    
1811        (e) Added the -o (--only-matching) option.
1812    
1813        (f) If -A or -C was used with -c (count only), some lines of context were
1814            accidentally printed for the final match.
1815    
1816        (g) Added the -H (--with-filename) option.
1817    
1818        (h) The combination of options -rh failed to suppress file names for files
1819            that were found from directory arguments.
1820    
1821        (i) Added the -D (--devices) and -d (--directories) options.
1822    
1823        (j) Added the -F (--fixed-strings) option.
1824    
1825        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1826    
1827        (l) Added the --colo(u)r option.
1828    
1829        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1830            is not present by default.
1831    
1832     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1833        items such as (?R) or (?1), when the recursion could match a number of
1834        alternatives. If it matched one of the alternatives, but subsequently,
1835        outside the recursion, there was a failure, the code tried to back up into
1836        the recursion. However, because of the way PCRE is implemented, this is not
1837        possible, and the result was an incorrect result from the match.
1838    
1839        In order to prevent this happening, the specification of recursion has
1840        been changed so that all such subpatterns are automatically treated as
1841        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1842    
1843     4. I had overlooked the fact that, in some locales, there are characters for
1844        which isalpha() is true but neither isupper() nor islower() are true. In
1845        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1846        and ordfeminine) are like this. This affected the treatment of \w and \W
1847        when they appeared in character classes, but not when they appeared outside
1848        a character class. The bit map for "word" characters is now created
1849        separately from the results of isalnum() instead of just taking it from the
1850        upper, lower, and digit maps. (Plus the underscore character, of course.)
1851    
1852     5. The above bug also affected the handling of POSIX character classes such as
1853        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1854        permanent tables. Instead, the bit maps for such a class were previously
1855        created as the appropriate unions of the upper, lower, and digit bitmaps.
1856        Now they are created by subtraction from the [[:word:]] class, which has
1857        its own bitmap.
1858    
1859     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1860        It is created by subtracting the vertical space characters (\x09, \x0a,
1861        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1862        subtraction was done in the overall bitmap for a character class, meaning
1863        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1864        be recognized. This bug has been fixed.
1865    
1866     7. Patches from the folks at Google:
1867    
1868          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1869          real life, but is still worth protecting against".
1870    
1871          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1872          regular expressions".
1873    
1874          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1875          have it.
1876    
1877          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1878          "configure" and the latter not, in order to fix a problem somebody had
1879          with compiling the Arg class on HP-UX.
1880    
1881          (e) Improve the error-handling of the C++ wrapper a little bit.
1882    
1883          (f) New tests for checking recursion limiting.
1884    
1885     8. The pcre_memmove() function, which is used only if the environment does not
1886        have a standard memmove() function (and is therefore rarely compiled),
1887        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1888        returning a result (though PCRE never actually uses the result).
1889    
1890     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1891        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1892        returned instead of calling malloc() with an overflowing number that would
1893        most likely cause subsequent chaos.
1894    
1895    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1896    
1897    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1898        with this option is matched, the nmatch and pmatch options of regexec() are
1899        ignored.
1900    
1901    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1902        provided in case anyone wants to the the POSIX interface with UTF-8
1903        strings.
1904    
1905    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1906        C++ linking (needed for some HP-UX environments).
1907    
1908    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1909        (unused parameter) and in the pcre_printint() function (omitted "default"
1910        switch label when the default is to do nothing).
1911    
1912    15. Added some code to make it possible, when PCRE is compiled as a C++
1913        library, to replace subject pointers for pcre_exec() with a smart pointer
1914        class, thus making it possible to process discontinuous strings.
1915    
1916    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1917        much the same function. They were added by different people who were trying
1918        to make PCRE easy to compile on non-Unix systems. It has been suggested
1919        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1920        for compiling on Windows systems. I have therefore replaced it with
1921        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1922        defaults to "extern" for C or "extern C" for C++, which works fine on
1923        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1924        SCOPE with something explicit in config.h. In addition:
1925    
1926        (a) pcreposix.h still had just "extern" instead of either of these macros;
1927            I have replaced it with PCRE_DATA_SCOPE.
1928    
1929        (b) Functions such as _pcre_xclass(), which are internal to the library,
1930            but external in the C sense, all had PCRE_EXPORT in their definitions.
1931            This is apparently wrong for the Windows case, so I have removed it.
1932            (It makes no difference on Unix-like systems.)
1933    
1934    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1935        of recursive calls to match(). This is different to MATCH_LIMIT because
1936        that limits the total number of calls to match(), not all of which increase
1937        the depth of recursion. Limiting the recursion depth limits the amount of
1938        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1939        when PCRE is compiled, and changed at run time. A patch from Google adds
1940        this functionality to the C++ interface.
1941    
1942    18. Changes to the handling of Unicode character properties:
1943    
1944        (a) Updated the table to Unicode 4.1.0.
1945    
1946        (b) Recognize characters that are not in the table as "Cn" (undefined).
1947    
1948        (c) I revised the way the table is implemented to a much improved format
1949            which includes recognition of ranges. It now supports the ranges that
1950            are defined in UnicodeData.txt, and it also amalgamates other
1951            characters into ranges. This has reduced the number of entries in the
1952            table from around 16,000 to around 3,000, thus reducing its size
1953            considerably. I realized I did not need to use a tree structure after
1954            all - a binary chop search is just as efficient. Having reduced the
1955            number of entries, I extended their size from 6 bytes to 8 bytes to
1956            allow for more data.
1957    
1958        (d) Added support for Unicode script names via properties such as \p{Han}.
1959    
1960    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1961        matching that character.
1962    
1963    20. When matching a repeated Unicode property with a minimum greater than zero,
1964        (for example \pL{2,}), PCRE could look past the end of the subject if it
1965        reached it while seeking the minimum number of characters. This could
1966        happen only if some of the characters were more than one byte long, because
1967        there is a check for at least the minimum number of bytes.
1968    
1969    21. Refactored the implementation of \p and \P so as to be more general, to
1970        allow for more different types of property in future. This has changed the
1971        compiled form incompatibly. Anybody with saved compiled patterns that use
1972        \p or \P will have to recompile them.
1973    
1974    22. Added "Any" and "L&" to the supported property types.
1975    
1976    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1977        but give a compile time error if the value is greater than 0xff.
1978    
1979    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1980        accidentally not being installed or uninstalled.
1981    
1982    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1983        made were to insert the current release number. This seemed silly, because
1984        it made things harder for people building PCRE on systems that don't run
1985        "configure". I have turned pcre.h into a distributed file, no longer built
1986        by "configure", with the version identification directly included. There is
1987        no longer a pcre.h.in file.
1988    
1989        However, this change necessitated a change to the pcre-config script as
1990        well. It is built from pcre-config.in, and one of the substitutions was the
1991        release number. I have updated configure.ac so that ./configure now finds
1992        the release number by grepping pcre.h.
1993    
1994    26. Added the ability to run the tests under valgrind.
1995    
1996    
1997    Version 6.4 05-Sep-05
1998    ---------------------
1999    
2000     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2001        "--" to be printed when multiple files were scanned, even when none of the
2002        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2003        consider it to be a bug, and have restored the previous behaviour.
2004    
2005     2. A couple of code tidies to get rid of compiler warnings.
2006    
2007     3. The pcretest program used to cheat by referring to symbols in the library
2008        whose names begin with _pcre_. These are internal symbols that are not
2009        really supposed to be visible externally, and in some environments it is
2010        possible to suppress them. The cheating is now confined to including
2011        certain files from the library's source, which is a bit cleaner.
2012    
2013     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2014        file's purpose clearer.
2015    
2016     5. Reorganized pcre_ucp_findchar().
2017    
2018    
2019    Version 6.3 15-Aug-05
2020    ---------------------
2021    
2022     1. The file libpcre.pc.in did not have general read permission in the tarball.
2023    
2024     2. There were some problems when building without C++ support:
2025    
2026        (a) If C++ support was not built, "make install" and "make test" still
2027            tried to test it.
2028    
2029        (b) There were problems when the value of CXX was explicitly set. Some
2030            changes have been made to try to fix these, and ...
2031    
2032        (c) --disable-cpp can now be used to explicitly disable C++ support.
2033    
2034        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2035            backslash in a target when C++ was disabled. This confuses some
2036            versions of "make", apparently. Using an intermediate variable solves
2037            this. (Same for CPP_LOBJ.)
2038    
2039     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2040        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2041        necessary on certain architectures.
2042    
2043     4. Added a setting of -export-symbols-regex to the link command to remove
2044        those symbols that are exported in the C sense, but actually are local
2045        within the library, and not documented. Their names all begin with
2046        "_pcre_". This is not a perfect job, because (a) we have to except some
2047        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2048        available (and never for static libraries). I have made a note to try to
2049        find a way round (a) in the future.
2050    
2051    
2052    Version 6.2 01-Aug-05
2053    ---------------------
2054    
2055     1. There was no test for integer overflow of quantifier values. A construction
2056        such as {1111111111111111} would give undefined results. What is worse, if
2057        a minimum quantifier for a parenthesized subpattern overflowed and became
2058        negative, the calculation of the memory size went wrong. This could have
2059        led to memory overwriting.
2060    
2061     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2062    
2063     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2064        operating environments where this matters.
2065    
2066     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2067        PCRE options from within the C++ wrapper.
2068    
2069     5. Named capturing subpatterns were not being correctly counted when a pattern
2070        was compiled. This caused two problems: (a) If there were more than 100
2071        such subpatterns, the calculation of the memory needed for the whole
2072        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2073        back references of the form \12, where the number was greater than 9, were
2074        not recognized as back references, even though there were sufficient
2075        previous subpatterns.
2076    
2077     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2078        versions of gcc, e.g. 2.95.4.
2079    
2080    
2081    Version 6.1 21-Jun-05
2082    ---------------------
2083    
2084     1. There was one reference to the variable "posix" in pcretest.c that was not
2085        surrounded by "#if !defined NOPOSIX".
2086    
2087     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2088        the cross-check on the old pcre_info() function, for the benefit of the
2089        cut-down version of PCRE that is currently imported into Exim.
2090    
2091     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2092        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2093        patterns that start (?i) but I don't think that matters. The use of (?i) is
2094        just an example; this all applies to the other options as well.
2095    
2096     4. Since libtool seems to echo the compile commands it is issuing, the output
2097        from "make" can be reduced a bit by putting "@" in front of each libtool
2098        compile command.
2099    
2100     5. Patch from the folks at Google for configure.in to be a bit more thorough
2101        in checking for a suitable C++ installation before trying to compile the
2102        C++ stuff. This should fix a reported problem when a compiler was present,
2103        but no suitable headers.
2104    
2105     6. The man pages all had just "PCRE" as their title. I have changed them to
2106        be the relevant file name. I have also arranged that these names are
2107        retained in the file doc/pcre.txt, which is a concatenation in text format
2108        of all the man pages except the little individual ones for each function.
2109    
2110     7. The NON-UNIX-USE file had not been updated for the different set of source
2111        files that come with release 6. I also added a few comments about the C++
2112        wrapper.
2113    
2114    
2115  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
2116  ---------------------  ---------------------
2117    

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