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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.10 03 May-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    3.  Inside a character class, \B is treated as a literal by default, but
13        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
14        causes the error). The code is unchanged, but I tidied the documentation.
15    
16    4.  Inside a character class, PCRE always treated \R and \X as literals,
17        whereas Perl faults them if its -w option is set. I have changed PCRE so
18        that it faults them when PCRE_EXTRA is set.
19    
20    5.  Added support for \N, which always matches any character other than
21        newline. (It is the same as "." when PCRE_DOTALL is not set.)
22    
23    
24    Version 8.02 19-Mar-2010
25    ------------------------
26    
27    1.  The Unicode data tables have been updated to Unicode 5.2.0.
28    
29    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
30        configured.
31    
32    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
33        original author of that file, following a query about its status.
34    
35    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
36        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
37    
38    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
39        quantifier applied to a forward-referencing subroutine call, could compile
40        incorrect code or give the error "internal error: previously-checked
41        referenced subpattern not found".
42    
43    6.  Both MS Visual Studio and Symbian OS have problems with initializing
44        variables to point to external functions. For these systems, therefore,
45        pcre_malloc etc. are now initialized to local functions that call the
46        relevant global functions.
47    
48    7.  There were two entries missing in the vectors called coptable and poptable
49        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
50        I've fixed the data, and added a kludgy way of testing at compile time that
51        the lengths are correct (equal to the number of opcodes).
52    
53    8.  Following on from 7, I added a similar kludge to check the length of the
54        eint vector in pcreposix.c.
55    
56    9.  Error texts for pcre_compile() are held as one long string to avoid too
57        much relocation at load time. To find a text, the string is searched,
58        counting zeros. There was no check for running off the end of the string,
59        which could happen if a new error number was added without updating the
60        string.
61    
62    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
63    
64    11. \K was not working if it appeared in an atomic group or in a group that
65        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
66        \K is "not well defined" if used in an assertion. PCRE now accepts it if
67        the assertion is positive, but not if it is negative.
68    
69    12. Change 11 fortuitously reduced the size of the stack frame used in the
70        "match()" function of pcre_exec.c by one pointer. Forthcoming
71        implementation of support for (*MARK) will need an extra pointer on the
72        stack; I have reserved it now, so that the stack frame size does not
73        decrease.
74    
75    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
76        item in branch that calls a recursion is a subroutine call - as in the
77        second branch in the above example - was incorrectly given the compile-
78        time error "recursive call could loop indefinitely" because pcre_compile()
79        was not correctly checking the subroutine for matching a non-empty string.
80    
81    14. The checks for overrunning compiling workspace could trigger after an
82        overrun had occurred. This is a "should never occur" error, but it can be
83        triggered by pathological patterns such as hundreds of nested parentheses.
84        The checks now trigger 100 bytes before the end of the workspace.
85    
86    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
87    
88    
89    Version 8.01 19-Jan-2010
90    ------------------------
91    
92    1.  If a pattern contained a conditional subpattern with only one branch (in
93        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
94        computed the wrong minimum data length (which is of course zero for such
95        subpatterns). This could cause incorrect "no match" results.
96    
97    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
98        the pattern is reset in the first branch, pcre_compile() failed with
99        "internal error: code overflow at offset...". This happened only when
100        the reset was to the original external option setting. (An optimization
101        abstracts leading options settings into an external setting, which was the
102        cause of this.)
103    
104    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
105        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
106        assertion pattern did not match (meaning that the assertion was true), it
107        was incorrectly treated as false if the SKIP had been reached during the
108        matching. This also applied to assertions used as conditions.
109    
110    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
111        assertion subpattern, including such a pattern used as a condition,
112        unpredictable results occurred, instead of the error return
113        PCRE_ERROR_DFA_UITEM.
114    
115    5.  The C++ GlobalReplace function was not working like Perl for the special
116        situation when an empty string is matched. It now does the fancy magic
117        stuff that is necessary.
118    
119    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
120        removed. (These were left over from very, very early versions of PCRE.)
121    
122    7.  Some cosmetic changes to the code to make life easier when compiling it
123        as part of something else:
124    
125        (a) Change DEBUG to PCRE_DEBUG.
126    
127        (b) In pcre_compile(), rename the member of the "branch_chain" structure
128            called "current" as "current_branch", to prevent a collision with the
129            Linux macro when compiled as a kernel module.
130    
131        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
132            prevent a collision with the Linux macro when compiled as a kernel
133            module.
134    
135    8.  In pcre_compile() there are some checks for integer overflows that used to
136        cast potentially large values to (double). This has been changed to that
137        when building, a check for int64_t is made, and if it is found, it is used
138        instead, thus avoiding the use of floating point arithmetic. (There is no
139        other use of FP in PCRE.) If int64_t is not found, the fallback is to
140        double.
141    
142    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
143        2005 (difference between two addresses compared to an unsigned value).
144    
145    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
146        custom one, because of the following reported problem in Windows:
147    
148          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
149              under Win32.
150          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
151              therefore missing the function definition.
152          - The compiler thus generates a "C" signature for the test function.
153          - The linker fails to find the "C" function.
154          - PCRE fails to configure if asked to do so against libbz2.
155    
156    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
157        messages were output:
158    
159          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
160          rerunning libtoolize, to keep the correct libtool macros in-tree.
161          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
162    
163        I have done both of these things.
164    
165    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
166        most of the time, it *can* run out if it is given a pattern that contains a
167        runaway infinite recursion. I updated the discussion in the pcrestack man
168        page.
169    
170    13. Now that we have gone to the x.xx style of version numbers, the minor
171        version may start with zero. Using 08 or 09 is a bad idea because users
172        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
173        interpreted as invalid octal numbers. I've updated the previous comment in
174        configure.ac, and also added a check that gives an error if 08 or 09 are
175        used.
176    
177    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
178        causing partial matching to fail when the end of the subject matched \W
179        in a UTF-8 pattern where \W was quantified with a minimum of 3.
180    
181    15. There were some discrepancies between the declarations in pcre_internal.h
182        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
183        their definitions. The declarations used "const uschar *" and the
184        definitions used USPTR. Even though USPTR is normally defined as "const
185        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
186        reported that: "This difference in casting confuses some C++ compilers, for
187        example, SunCC recognizes above declarations as different functions and
188        generates broken code for hbpcre." I have changed the declarations to use
189        USPTR.
190    
191    16. GNU libtool is named differently on some systems. The autogen.sh script now
192        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
193        (FreeBSD).
194    
195    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
196        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
197        comment: "Figure out how to create a longlong from a string: strtoll and
198        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
199        instance, but it only takes 2 args instead of 3!"
200    
201    18. A subtle bug concerned with back references has been fixed by a change of
202        specification, with a corresponding code fix. A pattern such as
203        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
204        refers, was giving matches when it shouldn't. For example, xa=xaaa would
205        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
206        same bug. Such groups have to be quantified to be useful, or contained
207        inside another quantified group. (If there's no repetition, the reference
208        can never match.) The problem arises because, having left the group and
209        moved on to the rest of the pattern, a later failure that backtracks into
210        the group uses the captured value from the final iteration of the group
211        rather than the correct earlier one. I have fixed this in PCRE by forcing
212        any group that contains a reference to itself to be an atomic group; that
213        is, there cannot be any backtracking into it once it has completed. This is
214        similar to recursive and subroutine calls.
215    
216    
217    Version 8.00 19-Oct-09
218    ----------------------
219    
220    1.  The table for translating pcre_compile() error codes into POSIX error codes
221        was out-of-date, and there was no check on the pcre_compile() error code
222        being within the table. This could lead to an OK return being given in
223        error.
224    
225    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
226        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
227        in a Windows environment.
228    
229    3.  The pcregrep --count option prints the count for each file even when it is
230        zero, as does GNU grep. However, pcregrep was also printing all files when
231        --files-with-matches was added. Now, when both options are given, it prints
232        counts only for those files that have at least one match. (GNU grep just
233        prints the file name in this circumstance, but including the count seems
234        more useful - otherwise, why use --count?) Also ensured that the
235        combination -clh just lists non-zero counts, with no names.
236    
237    4.  The long form of the pcregrep -F option was incorrectly implemented as
238        --fixed_strings instead of --fixed-strings. This is an incompatible change,
239        but it seems right to fix it, and I didn't think it was worth preserving
240        the old behaviour.
241    
242    5.  The command line items --regex=pattern and --regexp=pattern were not
243        recognized by pcregrep, which required --regex pattern or --regexp pattern
244        (with a space rather than an '='). The man page documented the '=' forms,
245        which are compatible with GNU grep; these now work.
246    
247    6.  No libpcreposix.pc file was created for pkg-config; there was just
248        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
249    
250    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
251        when UCP support is not needed, by modifying the Python script that
252        generates it from Unicode data files. This should not matter if the module
253        is correctly used as a library, but I received one complaint about 50K of
254        unwanted data. My guess is that the person linked everything into his
255        program rather than using a library. Anyway, it does no harm.
256    
257    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
258        was a minimum greater than 1 for a wide character in a possessive
259        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
260        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
261        character. Chaos in the form of incorrect output or a compiling loop could
262        result.
263    
264    9.  The restrictions on what a pattern can contain when partial matching is
265        requested for pcre_exec() have been removed. All patterns can now be
266        partially matched by this function. In addition, if there are at least two
267        slots in the offset vector, the offset of the earliest inspected character
268        for the match and the offset of the end of the subject are set in them when
269        PCRE_ERROR_PARTIAL is returned.
270    
271    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
272        synonymous with PCRE_PARTIAL, for backwards compatibility, and
273        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
274        and may be more useful for multi-segment matching.
275    
276    11. Partial matching with pcre_exec() is now more intuitive. A partial match
277        used to be given if ever the end of the subject was reached; now it is
278        given only if matching could not proceed because another character was
279        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
280        string "Z", which now yields "no match" instead of "partial match". In the
281        case of pcre_dfa_exec(), "no match" is given if every matching path for the
282        final character ended with (*FAIL).
283    
284    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
285        if the pattern had a "must contain" character that was already found in the
286        earlier partial match, unless partial matching was again requested. For
287        example, with the pattern /dog.(body)?/, the "must contain" character is
288        "g". If the first part-match was for the string "dog", restarting with
289        "sbody" failed. This bug has been fixed.
290    
291    13. The string returned by pcre_dfa_exec() after a partial match has been
292        changed so that it starts at the first inspected character rather than the
293        first character of the match. This makes a difference only if the pattern
294        starts with a lookbehind assertion or \b or \B (\K is not supported by
295        pcre_dfa_exec()). It's an incompatible change, but it makes the two
296        matching functions compatible, and I think it's the right thing to do.
297    
298    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
299        so that the demonstration program is easily available in environments where
300        PCRE has not been installed from source.
301    
302    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
303        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
304        library.
305    
306    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
307        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
308        is not the first non-POSIX option to be added. Clearly some people find
309        these options useful.
310    
311    17. If a caller to the POSIX matching function regexec() passes a non-zero
312        value for nmatch with a NULL value for pmatch, the value of
313        nmatch is forced to zero.
314    
315    18. RunGrepTest did not have a test for the availability of the -u option of
316        the diff command, as RunTest does. It now checks in the same way as
317        RunTest, and also checks for the -b option.
318    
319    19. If an odd number of negated classes containing just a single character
320        interposed, within parentheses, between a forward reference to a named
321        subpattern and the definition of the subpattern, compilation crashed with
322        an internal error, complaining that it could not find the referenced
323        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
324        [The bug was that it was starting one character too far in when skipping
325        over the character class, thus treating the ] as data rather than
326        terminating the class. This meant it could skip too much.]
327    
328    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
329        /g option in pcretest when the pattern contains \K, which makes it possible
330        to have an empty string match not at the start, even when the pattern is
331        anchored. Updated pcretest and pcredemo to use this option.
332    
333    21. If the maximum number of capturing subpatterns in a recursion was greater
334        than the maximum at the outer level, the higher number was returned, but
335        with unset values at the outer level. The correct (outer level) value is
336        now given.
337    
338    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
339        PCRE did not set those parentheses (unlike Perl). I have now found a way to
340        make it do so. The string so far is captured, making this feature
341        compatible with Perl.
342    
343    23. The tests have been re-organized, adding tests 11 and 12, to make it
344        possible to check the Perl 5.10 features against Perl 5.10.
345    
346    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
347        pattern matches a fixed length string. PCRE did not allow this; now it
348        does. Neither allows recursion.
349    
350    25. I finally figured out how to implement a request to provide the minimum
351        length of subject string that was needed in order to match a given pattern.
352        (It was back references and recursion that I had previously got hung up
353        on.) This code has now been added to pcre_study(); it finds a lower bound
354        to the length of subject needed. It is not necessarily the greatest lower
355        bound, but using it to avoid searching strings that are too short does give
356        some useful speed-ups. The value is available to calling programs via
357        pcre_fullinfo().
358    
359    26. While implementing 25, I discovered to my embarrassment that pcretest had
360        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
361        study optimizations had never been tested with that matching function.
362        Oops. What is worse, even when it was passed study data, there was a bug in
363        pcre_dfa_exec() that meant it never actually used it. Double oops. There
364        were also very few tests of studied patterns with pcre_dfa_exec().
365    
366    27. If (?| is used to create subpatterns with duplicate numbers, they are now
367        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
368        on the other side of the coin, they are no longer allowed to have different
369        names, because these cannot be distinguished in PCRE, and this has caused
370        confusion. (This is a difference from Perl.)
371    
372    28. When duplicate subpattern names are present (necessarily with different
373        numbers, as required by 27 above), and a test is made by name in a
374        conditional pattern, either for a subpattern having been matched, or for
375        recursion in such a pattern, all the associated numbered subpatterns are
376        tested, and the overall condition is true if the condition is true for any
377        one of them. This is the way Perl works, and is also more like the way
378        testing by number works.
379    
380    
381    Version 7.9 11-Apr-09
382    ---------------------
383    
384    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
385        (pcretest), all targets were linked against these libraries. This included
386        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
387        libraries. This caused unwanted dependencies to be created. This problem
388        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
389        pcretest is linked with readline.
390    
391    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
392        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
393        moved outside it again, because FALSE and TRUE are already defined in AIX,
394        but BOOL is not.
395    
396    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
397        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
398    
399    4.  The pcregrep documentation said spaces were inserted as well as colons (or
400        hyphens) following file names and line numbers when outputting matching
401        lines. This is not true; no spaces are inserted. I have also clarified the
402        wording for the --colour (or --color) option.
403    
404    5.  In pcregrep, when --colour was used with -o, the list of matching strings
405        was not coloured; this is different to GNU grep, so I have changed it to be
406        the same.
407    
408    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
409        each matching line was coloured. Now it goes on to look for further matches
410        of any of the test patterns, which is the same behaviour as GNU grep.
411    
412    7.  A pattern that could match an empty string could cause pcregrep to loop; it
413        doesn't make sense to accept an empty string match in pcregrep, so I have
414        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
415        seems to be how GNU grep behaves.
416    
417    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
418        start or after a newline", because the conditional assertion was not being
419        correctly handled. The rule now is that both the assertion and what follows
420        in the first alternative must satisfy the test.
421    
422    9.  If auto-callout was enabled in a pattern with a conditional group whose
423        condition was an assertion, PCRE could crash during matching, both with
424        pcre_exec() and pcre_dfa_exec().
425    
426    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
427        used for matching.
428    
429    11. Unicode property support in character classes was not working for
430        characters (bytes) greater than 127 when not in UTF-8 mode.
431    
432    12. Added the -M command line option to pcretest.
433    
434    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
435    
436    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
437    
438    16. Added comments and documentation about mis-use of no_arg in the C++
439        wrapper.
440    
441    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
442        from Martin Jerabek that uses macro names for all relevant character and
443        string constants.
444    
445    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
446        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
447        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
448        these, but not everybody uses configure.
449    
450    19. A conditional group that had only one branch was not being correctly
451        recognized as an item that could match an empty string. This meant that an
452        enclosing group might also not be so recognized, causing infinite looping
453        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
454        with the subject "ab", where knowledge that the repeated group can match
455        nothing is needed in order to break the loop.
456    
457    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
458        exec(), but without supplying a callout function, matching went wrong.
459    
460    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
461        leak if the size of the offset vector was greater than 30. When the vector
462        is smaller, the saved offsets during recursion go onto a local stack
463        vector, but for larger vectors malloc() is used. It was failing to free
464        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
465        error, in fact).
466    
467    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
468        heapframe that is used only when UTF-8 support is enabled. This caused no
469        problem, but was untidy.
470    
471    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
472        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
473        included within another project.
474    
475    24. Steven Van Ingelgem's patches to add more options to the CMake support,
476        slightly modified by me:
477    
478          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
479              not building pcregrep.
480    
481          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
482              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
483    
484    25. Forward references, both numeric and by name, in patterns that made use of
485        duplicate group numbers, could behave incorrectly or give incorrect errors,
486        because when scanning forward to find the reference group, PCRE was not
487        taking into account the duplicate group numbers. A pattern such as
488        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
489    
490    26. Changed a few more instances of "const unsigned char *" to USPTR, making
491        the feature of a custom pointer more persuasive (as requested by a user).
492    
493    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
494        pcretest.c, inside #ifndefs, because it seems they are sometimes already
495        pre-defined.
496    
497    28. Added support for (*UTF8) at the start of a pattern.
498    
499    29. Arrange for flags added by the "release type" setting in CMake to be shown
500        in the configuration summary.
501    
502    
503    Version 7.8 05-Sep-08
504    ---------------------
505    
506    1.  Replaced UCP searching code with optimized version as implemented for Ad
507        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
508        stage table and inline lookup instead of a function, giving speed ups of 2
509        to 5 times on some simple patterns that I tested. Permission was given to
510        distribute the MultiStage2.py script that generates the tables (it's not in
511        the tarball, but is in the Subversion repository).
512    
513    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
514        scripts.
515    
516    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
517        a group with a zero qualifier. The result of the study could be incorrect,
518        or the function might crash, depending on the pattern.
519    
520    4.  Caseless matching was not working for non-ASCII characters in back
521        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
522        It now works when Unicode Property Support is available.
523    
524    5.  In pcretest, an escape such as \x{de} in the data was always generating
525        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
526        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
527        truncation.
528    
529    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
530    
531    7.  Added two (int) casts to pcregrep when printing the difference of two
532        pointers, in case they are 64-bit values.
533    
534    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
535        test 2 if it fails.
536    
537    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
538        and a #define of that name to empty if it is not externally set. This is to
539        allow users of MSVC to set it if necessary.
540    
541    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
542        the convenience functions in the pcre_get.c source file.
543    
544    11. An option change at the start of a pattern that had top-level alternatives
545        could cause overwriting and/or a crash. This command provoked a crash in
546        some environments:
547    
548          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
549    
550        This potential security problem was recorded as CVE-2008-2371.
551    
552    12. For a pattern where the match had to start at the beginning or immediately
553        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
554        pcre_dfa_exec() could read past the end of the passed subject if there was
555        no match. To help with detecting such bugs (e.g. with valgrind), I modified
556        pcretest so that it places the subject at the end of its malloc-ed buffer.
557    
558    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
559        exec() might read past the end of the data buffer in UTF-8 mode.
560    
561    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
562        the data contained the byte 0x85 as part of a UTF-8 character within its
563        first line. This applied both to normal and DFA matching.
564    
565    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
566        /^[^d]*?$/8 failed to match "abc".
567    
568    16. Added a missing copyright notice to pcrecpp_internal.h.
569    
570    17. Make it more clear in the documentation that values returned from
571        pcre_exec() in ovector are byte offsets, not character counts.
572    
573    18. Tidied a few places to stop certain compilers from issuing warnings.
574    
575    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
576        supplied by Stefan Weber. I made a further small update for 7.8 because
577        there is a change of source arrangements: the pcre_searchfuncs.c module is
578        replaced by pcre_ucd.c.
579    
580    
581    Version 7.7 07-May-08
582    ---------------------
583    
584    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
585        a string to a long long, pretend we don't even have a long long." This is
586        done by checking for the strtoq, strtoll, and _strtoi64 functions.
587    
588    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
589        pre-7.6 versions, which defined a global no_arg variable instead of putting
590        it in the RE class. (See also #8 below.)
591    
592    3.  Remove a line of dead code, identified by coverity and reported by Nuno
593        Lopes.
594    
595    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
596    
597        (1) The include/exclude patterns were being applied to the whole pathnames
598            of files, instead of just to the final components.
599    
600        (2) If there was more than one level of directory, the subdirectories were
601            skipped unless they satisfied the include/exclude conditions. This is
602            inconsistent with GNU grep (and could even be seen as contrary to the
603            pcregrep specification - which I improved to make it absolutely clear).
604            The action now is always to scan all levels of directory, and just
605            apply the include/exclude patterns to regular files.
606    
607    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
608        --exclude_dir in the tests to avoid scanning .svn directories.
609    
610    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
611        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
612        doesn't support NULs in patterns.
613    
614    7.  Added some missing "const"s to declarations of static tables in
615        pcre_compile.c and pcre_dfa_exec.c.
616    
617    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
618        caused by fix #2  above. (Subsequently also a second patch to fix the
619        first patch. And a third patch - this was a messy problem.)
620    
621    9.  Applied Craig's patch to remove the use of push_back().
622    
623    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
624        matching function regexec().
625    
626    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
627        which, however, unlike Perl's \g{...}, are subroutine calls, not back
628        references. PCRE supports relative numbers with this syntax (I don't think
629        Oniguruma does).
630    
631    12. Previously, a group with a zero repeat such as (...){0} was completely
632        omitted from the compiled regex. However, this means that if the group
633        was called as a subroutine from elsewhere in the pattern, things went wrong
634        (an internal error was given). Such groups are now left in the compiled
635        pattern, with a new opcode that causes them to be skipped at execution
636        time.
637    
638    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
639        to the way PCRE behaves:
640    
641        (a) A lone ] character is dis-allowed (Perl treats it as data).
642    
643        (b) A back reference to an unmatched subpattern matches an empty string
644            (Perl fails the current match path).
645    
646        (c) A data ] in a character class must be notated as \] because if the
647            first data character in a class is ], it defines an empty class. (In
648            Perl it is not possible to have an empty class.) The empty class []
649            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
650            The negative empty class [^] matches any one character, independently
651            of the DOTALL setting.
652    
653    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
654        non-existent subpattern following a character class starting with ']' and
655        containing () gave an internal compiling error instead of "reference to
656        non-existent subpattern". Fortunately, when the pattern did exist, the
657        compiled code was correct. (When scanning forwards to check for the
658        existencd of the subpattern, it was treating the data ']' as terminating
659        the class, so got the count wrong. When actually compiling, the reference
660        was subsequently set up correctly.)
661    
662    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
663        it was being rejected as not supported by pcre_dfa_exec(), even though
664        other assertions are supported. I have made pcre_dfa_exec() support
665        (*FAIL).
666    
667    16. The implementation of 13c above involved the invention of a new opcode,
668        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
669        cannot be changed at match time, I realized I could make a small
670        improvement to matching performance by compiling OP_ALLANY instead of
671        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
672        on the OP_ANY path.
673    
674    17. Compiling pcretest on Windows with readline support failed without the
675        following two fixes: (1) Make the unistd.h include conditional on
676        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
677    
678    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
679        ncurses library to be included for pcretest when ReadLine support is
680        requested, but also to allow for it to be overridden. This patch came from
681        Daniel Bergström.
682    
683    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
684        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
685        any errors with the current Unicode tables. Thanks to Peter Kankowski for
686        spotting this.
687    
688    
689    Version 7.6 28-Jan-08
690    ---------------------
691    
692    1.  A character class containing a very large number of characters with
693        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
694        overflow.
695    
696    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
697        HAVE_LONG_LONG is not defined.
698    
699    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
700        bring them up to date and include new features. This patch includes:
701    
702        - Fixed PH's badly added libz and libbz2 support.
703        - Fixed a problem with static linking.
704        - Added pcredemo. [But later removed - see 7 below.]
705        - Fixed dftables problem and added an option.
706        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
707            HAVE_LONG_LONG.
708        - Added readline support for pcretest.
709        - Added an listing of the option settings after cmake has run.
710    
711    4.  A user submitted a patch to Makefile that makes it easy to create
712        "pcre.dll" under mingw when using Configure/Make. I added stuff to
713        Makefile.am that cause it to include this special target, without
714        affecting anything else. Note that the same mingw target plus all
715        the other distribution libraries and programs are now supported
716        when configuring with CMake (see 6 below) instead of with
717        Configure/Make.
718    
719    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
720        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
721        exported in the Windows port". It has not yet been confirmed that the patch
722        solves the problem, but it does no harm.
723    
724    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
725        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
726        with CMake, and also correct the comment about stack recursion.
727    
728    7.  Remove the automatic building of pcredemo from the ./configure system and
729        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
730        of a program that users should build themselves after PCRE is installed, so
731        building it automatically is not really right. What is more, it gave
732        trouble in some build environments.
733    
734    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
735    
736    
737    Version 7.5 10-Jan-08
738    ---------------------
739    
740    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
741        values in parens when parsing an RE using the C++ wrapper."
742    
743    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
744        Characters greater than 255 were excluded from the class instead of being
745        included.
746    
747    3.  The same bug as (2) above applied to negated POSIX classes such as
748        [:^space:].
749    
750    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
751        defined or documented. It seems to have been a typo for PCRE_STATIC, so
752        I have changed it.
753    
754    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
755        first named subpattern) and a construct such as (?&a) would reference the
756        first named subpattern whose name started with "a" (in other words, the
757        length check was missing). Both these problems are fixed. "Subpattern name
758        expected" is now given for (?&) (a zero-length name), and this patch also
759        makes it give the same error for \k'' (previously it complained that that
760        was a reference to a non-existent subpattern).
761    
762    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
763        this is right because (?- can be followed by option settings as well as by
764        digits. I have, however, made the messages clearer.
765    
766    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
767        than the number used in the conditional) now cause a compile-time error.
768        This is actually not compatible with Perl, which accepts such patterns, but
769        treats the conditional as always being FALSE (as PCRE used to), but it
770        seems to me that giving a diagnostic is better.
771    
772    8.  Change "alphameric" to the more common word "alphanumeric" in comments
773        and messages.
774    
775    9.  Fix two occurrences of "backslash" in comments that should have been
776        "backspace".
777    
778    10. Remove two redundant lines of code that can never be obeyed (their function
779        was moved elsewhere).
780    
781    11. The program that makes PCRE's Unicode character property table had a bug
782        which caused it to generate incorrect table entries for sequences of
783        characters that have the same character type, but are in different scripts.
784        It amalgamated them into a single range, with the script of the first of
785        them. In other words, some characters were in the wrong script. There were
786        thirteen such cases, affecting characters in the following ranges:
787    
788          U+002b0 - U+002c1
789          U+0060c - U+0060d
790          U+0061e - U+00612
791          U+0064b - U+0065e
792          U+0074d - U+0076d
793          U+01800 - U+01805
794          U+01d00 - U+01d77
795          U+01d9b - U+01dbf
796          U+0200b - U+0200f
797          U+030fc - U+030fe
798          U+03260 - U+0327f
799          U+0fb46 - U+0fbb1
800          U+10450 - U+1049d
801    
802    12. The -o option (show only the matching part of a line) for pcregrep was not
803        compatible with GNU grep in that, if there was more than one match in a
804        line, it showed only the first of them. It now behaves in the same way as
805        GNU grep.
806    
807    13. If the -o and -v options were combined for pcregrep, it printed a blank
808        line for every non-matching line. GNU grep prints nothing, and pcregrep now
809        does the same. The return code can be used to tell if there were any
810        non-matching lines.
811    
812    14. Added --file-offsets and --line-offsets to pcregrep.
813    
814    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
815        infinitely looping recursion. The bug was that positive lookaheads were not
816        being skipped when checking for a possible empty match (negative lookaheads
817        and both kinds of lookbehind were skipped).
818    
819    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
820        inclusion of <windows.h> to before rather than after the definition of
821        INVALID_FILE_ATTRIBUTES (patch from David Byron).
822    
823    17. Specifying a possessive quantifier with a specific limit for a Unicode
824        character property caused pcre_compile() to compile bad code, which led at
825        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
826        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
827        caused the error; without that there was no problem.
828    
829    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
830    
831    19. Added --enable-pcretest-libreadline.
832    
833    20. In pcrecpp.cc, the variable 'count' was incremented twice in
834        RE::GlobalReplace(). As a result, the number of replacements returned was
835        double what it should be. I removed one of the increments, but Craig sent a
836        later patch that removed the other one (the right fix) and added unit tests
837        that check the return values (which was not done before).
838    
839    21. Several CMake things:
840    
841        (1) Arranged that, when cmake is used on Unix, the libraries end up with
842            the names libpcre and libpcreposix, not just pcre and pcreposix.
843    
844        (2) The above change means that pcretest and pcregrep are now correctly
845            linked with the newly-built libraries, not previously installed ones.
846    
847        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
848    
849    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
850        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
851        UTF-8 newline character). The key issue is that the pattern starts .*;
852        this means that the match must be either at the beginning, or after a
853        newline. The bug was in the code for advancing after a failed match and
854        checking that the new position followed a newline. It was not taking
855        account of UTF-8 characters correctly.
856    
857    23. PCRE was behaving differently from Perl in the way it recognized POSIX
858        character classes. PCRE was not treating the sequence [:...:] as a
859        character class unless the ... were all letters. Perl, however, seems to
860        allow any characters between [: and :], though of course it rejects as
861        unknown any "names" that contain non-letters, because all the known class
862        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
863        for example, whereas PCRE did not - it did not recognize a POSIX character
864        class. This seemed a bit dangerous, so the code has been changed to be
865        closer to Perl. The behaviour is not identical to Perl, because PCRE will
866        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
867        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
868        Perl does, and where it didn't before.
869    
870    24. Rewrite so as to remove the single use of %n from pcregrep because in some
871        Windows environments %n is disabled by default.
872    
873    
874    Version 7.4 21-Sep-07
875    ---------------------
876    
877    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
878        means that a class such as [\s] counted as "explicit reference to CR or
879        LF". That isn't really right - the whole point of the change was to try to
880        help when there was an actual mention of one of the two characters. So now
881        the change happens only if \r or \n (or a literal CR or LF) character is
882        encountered.
883    
884    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
885        of both had grown to the point where there were only 3 bits left.
886        Fortunately, there was spare space in the data structure, and so I have
887        moved the internal flags into a new 16-bit field to free up more option
888        bits.
889    
890    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
891        but did not set the internal JCHANGED flag - either of these is enough to
892        control the way the "get" function works - but the PCRE_INFO_JCHANGED
893        facility is supposed to tell if (?J) was ever used, so now (?J) at the
894        start sets both bits.
895    
896    4.  Added options (at build time, compile time, exec time) to change \R from
897        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
898    
899    5.  doc/pcresyntax.html was missing from the distribution.
900    
901    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
902        compatibility, even though it is no longer used.
903    
904    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
905        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
906        windows.h file is present (where different names are used). [This was
907        reversed later after testing - see 16 below.]
908    
909    8.  Changed all #include <config.h> to #include "config.h". There were also
910        some further <pcre.h> cases that I changed to "pcre.h".
911    
912    9.  When pcregrep was used with the --colour option, it missed the line ending
913        sequence off the lines that it output.
914    
915    10. It was pointed out to me that arrays of string pointers cause lots of
916        relocations when a shared library is dynamically loaded. A technique of
917        using a single long string with a table of offsets can drastically reduce
918        these. I have refactored PCRE in four places to do this. The result is
919        dramatic:
920    
921          Originally:                          290
922          After changing UCP table:            187
923          After changing error message table:   43
924          After changing table of "verbs"       36
925          After changing table of Posix names   22
926    
927        Thanks to the folks working on Gregex for glib for this insight.
928    
929    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
930        unicode-properties was also set.
931    
932    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
933    
934    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
935        checked only for CRLF.
936    
937    14. Added casts to pcretest.c to avoid compiler warnings.
938    
939    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
940    
941    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
942        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
943        entirely. This removes changes made in 7 above.
944    
945    17. The CMake files have been updated, and there is now more information about
946        building with CMake in the NON-UNIX-USE document.
947    
948    
949    Version 7.3 28-Aug-07
950    ---------------------
951    
952     1. In the rejigging of the build system that eventually resulted in 7.1, the
953        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
954        brackets there is not right, since it causes compilers to look for an
955        installed pcre.h, not the version that is in the source that is being
956        compiled (which of course may be different). I have changed it back to:
957    
958          #include "pcre.h"
959    
960        I have a vague recollection that the change was concerned with compiling in
961        different directories, but in the new build system, that is taken care of
962        by the VPATH setting the Makefile.
963    
964     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
965        when the subject happened to end in the byte 0x85 (e.g. if the last
966        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
967        characters but of course it shouldn't be taken as a newline when it is part
968        of another character. The bug was that, for an unlimited repeat of . in
969        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
970        characters when looking for a newline.
971    
972     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
973    
974     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
975        in debug output.
976    
977     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
978        long printing in the pcrecpp unittest when running under MinGW.
979    
980     6. ESC_K was left out of the EBCDIC table.
981    
982     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
983        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
984        limit also applies to "virtual nesting" when a pattern is recursive, and in
985        this case 1000 isn't so big. I have been able to remove this limit at the
986        expense of backing off one optimization in certain circumstances. Normally,
987        when pcre_exec() would call its internal match() function recursively and
988        immediately return the result unconditionally, it uses a "tail recursion"
989        feature to save stack. However, when a subpattern that can match an empty
990        string has an unlimited repetition quantifier, it no longer makes this
991        optimization. That gives it a stack frame in which to save the data for
992        checking that an empty string has been matched. Previously this was taken
993        from the 1000-entry workspace that had been reserved. So now there is no
994        explicit limit, but more stack is used.
995    
996     8. Applied Daniel's patches to solve problems with the import/export magic
997        syntax that is required for Windows, and which was going wrong for the
998        pcreposix and pcrecpp parts of the library. These were overlooked when this
999        problem was solved for the main library.
1000    
1001     9. There were some crude static tests to avoid integer overflow when computing
1002        the size of patterns that contain repeated groups with explicit upper
1003        limits. As the maximum quantifier is 65535, the maximum group length was
1004        set at 30,000 so that the product of these two numbers did not overflow a
1005        32-bit integer. However, it turns out that people want to use groups that
1006        are longer than 30,000 bytes (though not repeat them that many times).
1007        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1008        made it possible to implement the integer overflow checks in a much more
1009        dynamic way, which I have now done. The artificial limitation on group
1010        length has been removed - we now have only the limit on the total length of
1011        the compiled pattern, which depends on the LINK_SIZE setting.
1012    
1013    10. Fixed a bug in the documentation for get/copy named substring when
1014        duplicate names are permitted. If none of the named substrings are set, the
1015        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1016        empty string.
1017    
1018    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1019        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1020        because the ] is interpreted as the first data character and the
1021        terminating ] is not found. PCRE has been made compatible with Perl in this
1022        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1023        cause memory overwriting.
1024    
1025    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1026        string has been matched (to stop an infinite loop). It was not recognizing
1027        a conditional subpattern that could match an empty string if that
1028        subpattern was within another subpattern. For example, it looped when
1029        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1030        condition was not nested. This bug has been fixed.
1031    
1032    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1033        past the start of the subject in the presence of bytes with the top bit
1034        set, for example "\x8aBCD".
1035    
1036    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1037        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1038    
1039    14. Optimized (?!) to (*FAIL).
1040    
1041    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1042        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1043        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1044        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1045        does: it's just the validity check that is more restrictive.
1046    
1047    16. Inserted checks for integer overflows during escape sequence (backslash)
1048        processing, and also fixed erroneous offset values for syntax errors during
1049        backslash processing.
1050    
1051    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1052        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1053    
1054    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1055        caused an overrun.
1056    
1057    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1058        something other than just ASCII characters) inside a group that had an
1059        unlimited repeat caused a loop at compile time (while checking to see
1060        whether the group could match an empty string).
1061    
1062    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1063        [\P{Any}] did so. (Error in the code for printing property names.)
1064    
1065    21. An orphan \E inside a character class could cause a crash.
1066    
1067    22. A repeated capturing bracket such as (A)? could cause a wild memory
1068        reference during compilation.
1069    
1070    23. There are several functions in pcre_compile() that scan along a compiled
1071        expression for various reasons (e.g. to see if it's fixed length for look
1072        behind). There were bugs in these functions when a repeated \p or \P was
1073        present in the pattern. These operators have additional parameters compared
1074        with \d, etc, and these were not being taken into account when moving along
1075        the compiled data. Specifically:
1076    
1077        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1078            length.
1079    
1080        (b) An item such as \pL+ within a repeated group could cause crashes or
1081            loops.
1082    
1083        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1084            "reference to non-existent subpattern" error.
1085    
1086        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1087    
1088    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1089        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1090    
1091    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1092    
1093    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1094        character were causing crashes (broken optimization).
1095    
1096    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1097        \p or \P) caused a compile-time loop.
1098    
1099    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1100        break. For example, the unstudied pattern [\r\n]A does not match the string
1101        "\r\nA" because change 7.0/46 below moves the current point on by two
1102        characters after failing to match at the start. However, the pattern \nA
1103        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1104        the same is true. There doesn't seem any very clean way out of this, but
1105        what I have chosen to do makes the common cases work: PCRE now takes note
1106        of whether there can be an explicit match for \r or \n anywhere in the
1107        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1108        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1109        pattern has explicit CR or LF references.
1110    
1111    29. Added (*CR) etc for changing newline setting at start of pattern.
1112    
1113    
1114    Version 7.2 19-Jun-07
1115    ---------------------
1116    
1117     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1118        which is apparently normally available under Windows.
1119    
1120     2. Re-jig the pcregrep tests with different newline settings in an attempt
1121        to make them independent of the local environment's newline setting.
1122    
1123     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1124    
1125     4. Some of the "internals" tests were previously cut out when the link size
1126        was not 2, because the output contained actual offsets. The recent new
1127        "Z" feature of pcretest means that these can be cut out, making the tests
1128        usable with all link sizes.
1129    
1130     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1131        stack recursion. This gives a massive performance boost under BSD, but just
1132        a small improvement under Linux. However, it saves one field in the frame
1133        in all cases.
1134    
1135     6. Added more features from the forthcoming Perl 5.10:
1136    
1137        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1138            recursion call. It refers to the nth most recently opened parentheses.
1139    
1140        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1141            to be opened parentheses.
1142    
1143        (c) Conditions that refer to capturing parentheses can be specified
1144            relatively, for example, (?(-2)... or (?(+3)...
1145    
1146        (d) \K resets the start of the current match so that everything before
1147            is not part of it.
1148    
1149        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1150    
1151        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1152            reference syntax.
1153    
1154        (g) (?| introduces a group in which the numbering of parentheses in each
1155            alternative starts with the same number.
1156    
1157        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1158    
1159     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1160        PCRE_INFO_JCHANGED.
1161    
1162     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1163        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1164        for detecting groups that can match an empty string.
1165    
1166     9. A pattern with a very large number of alternatives (more than several
1167        hundred) was running out of internal workspace during the pre-compile
1168        phase, where pcre_compile() figures out how much memory will be needed. A
1169        bit of new cunning has reduced the workspace needed for groups with
1170        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1171        workspace instead of running out of the 4096 that are available.
1172    
1173    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1174    
1175    11. Applied patch from Google to remove an optimization that didn't quite work.
1176        The report of the bug said:
1177    
1178          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1179          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1180          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1181    
1182    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1183        it matched the wrong number of bytes.
1184    
1185    
1186    Version 7.1 24-Apr-07
1187    ---------------------
1188    
1189     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1190        that is more "standard", making use of automake and other Autotools. There
1191        is some re-arrangement of the files and adjustment of comments consequent
1192        on this.
1193    
1194     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1195        for recursive directory scanning broke on some systems because the files
1196        are not scanned in any specific order and on different systems the order
1197        was different. A call to "sort" has been inserted into RunGrepTest for the
1198        approprate test as a short-term fix. In the longer term there may be an
1199        alternative.
1200    
1201     3. I had an email from Eric Raymond about problems translating some of PCRE's
1202        man pages to HTML (despite the fact that I distribute HTML pages, some
1203        people do their own conversions for various reasons). The problems
1204        concerned the use of low-level troff macros .br and .in. I have therefore
1205        removed all such uses from the man pages (some were redundant, some could
1206        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1207        HTML has been updated to handle .nf/.fi and to complain if it encounters
1208        .br or .in.
1209    
1210     4. Updated comments in configure.ac that get placed in config.h.in and also
1211        arranged for config.h to be included in the distribution, with the name
1212        config.h.generic, for the benefit of those who have to compile without
1213        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1214    
1215     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1216        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1217        makevp.bat for the current PCRE, using the additional files
1218        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1219    
1220     6. A Windows user reported a minor discrepancy with test 2, which turned out
1221        to be caused by a trailing space on an input line that had got lost in his
1222        copy. The trailing space was an accident, so I've just removed it.
1223    
1224     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1225        that is needed.
1226    
1227     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1228        as "const" (a) because they are and (b) because it helps the PHP
1229        maintainers who have recently made a script to detect big data structures
1230        in the php code that should be moved to the .rodata section. I remembered
1231        to update Builducptable as well, so it won't revert if ucptable.h is ever
1232        re-created.
1233    
1234     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1235        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1236        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1237        support is not required. This saves 1.5-2K of code, which is important in
1238        some applications.
1239    
1240        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1241        so as not to refer to the tables, even though these functions will never be
1242        called when UTF-8 support is disabled. Otherwise there are problems with a
1243        shared library.
1244    
1245    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1246    
1247        (a) It was defining its arguments as char * instead of void *.
1248    
1249        (b) It was assuming that all moves were upwards in memory; this was true
1250            a long time ago when I wrote it, but is no longer the case.
1251    
1252        The emulated memove() is provided for those environments that have neither
1253        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1254        is clearly not the case, as these two bugs were recently reported.
1255    
1256    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1257        and Detrail to create the HTML documentation, the .txt form of the man
1258        pages, and it removes trailing spaces from listed files. It also creates
1259        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1260        case, it wraps all the #defines with #ifndefs. This script should be run
1261        before "make dist".
1262    
1263    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1264        with Unicode property support.
1265    
1266        (a) For a maximizing quantifier, if the two different cases of the
1267            character were of different lengths in their UTF-8 codings (there are
1268            some cases like this - I found 11), and the matching function had to
1269            back up over a mixture of the two cases, it incorrectly assumed they
1270            were both the same length.
1271    
1272        (b) When PCRE was configured to use the heap rather than the stack for
1273            recursion during matching, it was not correctly preserving the data for
1274            the other case of a UTF-8 character when checking ahead for a match
1275            while processing a minimizing repeat. If the check also involved
1276            matching a wide character, but failed, corruption could cause an
1277            erroneous result when trying to check for a repeat of the original
1278            character.
1279    
1280    13. Some tidying changes to the testing mechanism:
1281    
1282        (a) The RunTest script now detects the internal link size and whether there
1283            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1284            values substituted by "configure". (The RunGrepTest script already did
1285            this for UTF-8.) The configure.ac script no longer substitutes the
1286            relevant variables.
1287    
1288        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1289            with length and offset values. This means that the output is different
1290            for different internal link sizes. Test 2 is skipped for link sizes
1291            other than 2 because of this, bypassing the problem. Unfortunately,
1292            there was also a test in test 3 (the locale tests) that used /B and
1293            failed for link sizes other than 2. Rather than cut the whole test out,
1294            I have added a new /Z option to pcretest that replaces the length and
1295            offset values with spaces. This is now used to make test 3 independent
1296            of link size. (Test 2 will be tidied up later.)
1297    
1298    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1299        segmentation fault instead of returning the appropriate error message.
1300    
1301    15. In multiline mode when the newline sequence was set to "any", the pattern
1302        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1303        This doesn't seem right; it now treats the CRLF combination as the line
1304        ending, and so does not match in that case. It's only a pattern such as ^$
1305        that would hit this one: something like ^ABC$ would have failed after \r
1306        and then tried again after \r\n.
1307    
1308    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1309        in an attempt to make files that differ only in their line terminators
1310        compare equal. This works on Linux.
1311    
1312    17. Under certain error circumstances pcregrep might try to free random memory
1313        as it exited. This is now fixed, thanks to valgrind.
1314    
1315    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1316        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1317        was because its rules for how to advance for /g after matching an empty
1318        string at the end of a line did not allow for this case. They now check for
1319        it specially.
1320    
1321    20. pcretest is supposed to handle patterns and data of any length, by
1322        extending its buffers when necessary. It was getting this wrong when the
1323        buffer for a data line had to be extended.
1324    
1325    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1326        CRLF as a newline sequence.
1327    
1328    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1329        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1330        I have nevertheless tidied it up.
1331    
1332    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1333    
1334    24. Added a man page for pcre-config.
1335    
1336    
1337  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
1338  ---------------------  ---------------------
1339    

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