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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    6.  When compiling pcregrep with newer versions of gcc which may have
24        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
25        declared with attribute warn_unused_result" were given. Just casting the
26        result to (void) does not stop the warnings; a more elaborate fudge is
27        needed. I've used a macro to implement this.
28    
29    
30    Version 8.02 19-Mar-2010
31    ------------------------
32    
33    1.  The Unicode data tables have been updated to Unicode 5.2.0.
34    
35    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
36        configured.
37    
38    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
39        original author of that file, following a query about its status.
40    
41    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
42        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
43    
44    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
45        quantifier applied to a forward-referencing subroutine call, could compile
46        incorrect code or give the error "internal error: previously-checked
47        referenced subpattern not found".
48    
49    6.  Both MS Visual Studio and Symbian OS have problems with initializing
50        variables to point to external functions. For these systems, therefore,
51        pcre_malloc etc. are now initialized to local functions that call the
52        relevant global functions.
53    
54    7.  There were two entries missing in the vectors called coptable and poptable
55        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
56        I've fixed the data, and added a kludgy way of testing at compile time that
57        the lengths are correct (equal to the number of opcodes).
58    
59    8.  Following on from 7, I added a similar kludge to check the length of the
60        eint vector in pcreposix.c.
61    
62    9.  Error texts for pcre_compile() are held as one long string to avoid too
63        much relocation at load time. To find a text, the string is searched,
64        counting zeros. There was no check for running off the end of the string,
65        which could happen if a new error number was added without updating the
66        string.
67    
68    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
69    
70    11. \K was not working if it appeared in an atomic group or in a group that
71        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
72        \K is "not well defined" if used in an assertion. PCRE now accepts it if
73        the assertion is positive, but not if it is negative.
74    
75    12. Change 11 fortuitously reduced the size of the stack frame used in the
76        "match()" function of pcre_exec.c by one pointer. Forthcoming
77        implementation of support for (*MARK) will need an extra pointer on the
78        stack; I have reserved it now, so that the stack frame size does not
79        decrease.
80    
81    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
82        item in branch that calls a recursion is a subroutine call - as in the
83        second branch in the above example - was incorrectly given the compile-
84        time error "recursive call could loop indefinitely" because pcre_compile()
85        was not correctly checking the subroutine for matching a non-empty string.
86    
87    14. The checks for overrunning compiling workspace could trigger after an
88        overrun had occurred. This is a "should never occur" error, but it can be
89        triggered by pathological patterns such as hundreds of nested parentheses.
90        The checks now trigger 100 bytes before the end of the workspace.
91    
92    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
93    
94    
95    Version 8.01 19-Jan-2010
96    ------------------------
97    
98    1.  If a pattern contained a conditional subpattern with only one branch (in
99        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
100        computed the wrong minimum data length (which is of course zero for such
101        subpatterns). This could cause incorrect "no match" results.
102    
103    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
104        the pattern is reset in the first branch, pcre_compile() failed with
105        "internal error: code overflow at offset...". This happened only when
106        the reset was to the original external option setting. (An optimization
107        abstracts leading options settings into an external setting, which was the
108        cause of this.)
109    
110    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
111        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
112        assertion pattern did not match (meaning that the assertion was true), it
113        was incorrectly treated as false if the SKIP had been reached during the
114        matching. This also applied to assertions used as conditions.
115    
116    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
117        assertion subpattern, including such a pattern used as a condition,
118        unpredictable results occurred, instead of the error return
119        PCRE_ERROR_DFA_UITEM.
120    
121    5.  The C++ GlobalReplace function was not working like Perl for the special
122        situation when an empty string is matched. It now does the fancy magic
123        stuff that is necessary.
124    
125    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
126        removed. (These were left over from very, very early versions of PCRE.)
127    
128    7.  Some cosmetic changes to the code to make life easier when compiling it
129        as part of something else:
130    
131        (a) Change DEBUG to PCRE_DEBUG.
132    
133        (b) In pcre_compile(), rename the member of the "branch_chain" structure
134            called "current" as "current_branch", to prevent a collision with the
135            Linux macro when compiled as a kernel module.
136    
137        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
138            prevent a collision with the Linux macro when compiled as a kernel
139            module.
140    
141    8.  In pcre_compile() there are some checks for integer overflows that used to
142        cast potentially large values to (double). This has been changed to that
143        when building, a check for int64_t is made, and if it is found, it is used
144        instead, thus avoiding the use of floating point arithmetic. (There is no
145        other use of FP in PCRE.) If int64_t is not found, the fallback is to
146        double.
147    
148    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
149        2005 (difference between two addresses compared to an unsigned value).
150    
151    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
152        custom one, because of the following reported problem in Windows:
153    
154          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
155              under Win32.
156          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
157              therefore missing the function definition.
158          - The compiler thus generates a "C" signature for the test function.
159          - The linker fails to find the "C" function.
160          - PCRE fails to configure if asked to do so against libbz2.
161    
162    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
163        messages were output:
164    
165          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
166          rerunning libtoolize, to keep the correct libtool macros in-tree.
167          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
168    
169        I have done both of these things.
170    
171    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
172        most of the time, it *can* run out if it is given a pattern that contains a
173        runaway infinite recursion. I updated the discussion in the pcrestack man
174        page.
175    
176    13. Now that we have gone to the x.xx style of version numbers, the minor
177        version may start with zero. Using 08 or 09 is a bad idea because users
178        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
179        interpreted as invalid octal numbers. I've updated the previous comment in
180        configure.ac, and also added a check that gives an error if 08 or 09 are
181        used.
182    
183    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
184        causing partial matching to fail when the end of the subject matched \W
185        in a UTF-8 pattern where \W was quantified with a minimum of 3.
186    
187    15. There were some discrepancies between the declarations in pcre_internal.h
188        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
189        their definitions. The declarations used "const uschar *" and the
190        definitions used USPTR. Even though USPTR is normally defined as "const
191        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
192        reported that: "This difference in casting confuses some C++ compilers, for
193        example, SunCC recognizes above declarations as different functions and
194        generates broken code for hbpcre." I have changed the declarations to use
195        USPTR.
196    
197    16. GNU libtool is named differently on some systems. The autogen.sh script now
198        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
199        (FreeBSD).
200    
201    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
202        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
203        comment: "Figure out how to create a longlong from a string: strtoll and
204        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
205        instance, but it only takes 2 args instead of 3!"
206    
207    18. A subtle bug concerned with back references has been fixed by a change of
208        specification, with a corresponding code fix. A pattern such as
209        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
210        refers, was giving matches when it shouldn't. For example, xa=xaaa would
211        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
212        same bug. Such groups have to be quantified to be useful, or contained
213        inside another quantified group. (If there's no repetition, the reference
214        can never match.) The problem arises because, having left the group and
215        moved on to the rest of the pattern, a later failure that backtracks into
216        the group uses the captured value from the final iteration of the group
217        rather than the correct earlier one. I have fixed this in PCRE by forcing
218        any group that contains a reference to itself to be an atomic group; that
219        is, there cannot be any backtracking into it once it has completed. This is
220        similar to recursive and subroutine calls.
221    
222    
223    Version 8.00 19-Oct-09
224    ----------------------
225    
226    1.  The table for translating pcre_compile() error codes into POSIX error codes
227        was out-of-date, and there was no check on the pcre_compile() error code
228        being within the table. This could lead to an OK return being given in
229        error.
230    
231    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
232        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
233        in a Windows environment.
234    
235    3.  The pcregrep --count option prints the count for each file even when it is
236        zero, as does GNU grep. However, pcregrep was also printing all files when
237        --files-with-matches was added. Now, when both options are given, it prints
238        counts only for those files that have at least one match. (GNU grep just
239        prints the file name in this circumstance, but including the count seems
240        more useful - otherwise, why use --count?) Also ensured that the
241        combination -clh just lists non-zero counts, with no names.
242    
243    4.  The long form of the pcregrep -F option was incorrectly implemented as
244        --fixed_strings instead of --fixed-strings. This is an incompatible change,
245        but it seems right to fix it, and I didn't think it was worth preserving
246        the old behaviour.
247    
248    5.  The command line items --regex=pattern and --regexp=pattern were not
249        recognized by pcregrep, which required --regex pattern or --regexp pattern
250        (with a space rather than an '='). The man page documented the '=' forms,
251        which are compatible with GNU grep; these now work.
252    
253    6.  No libpcreposix.pc file was created for pkg-config; there was just
254        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
255    
256    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
257        when UCP support is not needed, by modifying the Python script that
258        generates it from Unicode data files. This should not matter if the module
259        is correctly used as a library, but I received one complaint about 50K of
260        unwanted data. My guess is that the person linked everything into his
261        program rather than using a library. Anyway, it does no harm.
262    
263    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
264        was a minimum greater than 1 for a wide character in a possessive
265        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
266        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
267        character. Chaos in the form of incorrect output or a compiling loop could
268        result.
269    
270    9.  The restrictions on what a pattern can contain when partial matching is
271        requested for pcre_exec() have been removed. All patterns can now be
272        partially matched by this function. In addition, if there are at least two
273        slots in the offset vector, the offset of the earliest inspected character
274        for the match and the offset of the end of the subject are set in them when
275        PCRE_ERROR_PARTIAL is returned.
276    
277    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
278        synonymous with PCRE_PARTIAL, for backwards compatibility, and
279        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
280        and may be more useful for multi-segment matching.
281    
282    11. Partial matching with pcre_exec() is now more intuitive. A partial match
283        used to be given if ever the end of the subject was reached; now it is
284        given only if matching could not proceed because another character was
285        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
286        string "Z", which now yields "no match" instead of "partial match". In the
287        case of pcre_dfa_exec(), "no match" is given if every matching path for the
288        final character ended with (*FAIL).
289    
290    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
291        if the pattern had a "must contain" character that was already found in the
292        earlier partial match, unless partial matching was again requested. For
293        example, with the pattern /dog.(body)?/, the "must contain" character is
294        "g". If the first part-match was for the string "dog", restarting with
295        "sbody" failed. This bug has been fixed.
296    
297    13. The string returned by pcre_dfa_exec() after a partial match has been
298        changed so that it starts at the first inspected character rather than the
299        first character of the match. This makes a difference only if the pattern
300        starts with a lookbehind assertion or \b or \B (\K is not supported by
301        pcre_dfa_exec()). It's an incompatible change, but it makes the two
302        matching functions compatible, and I think it's the right thing to do.
303    
304    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
305        so that the demonstration program is easily available in environments where
306        PCRE has not been installed from source.
307    
308    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
309        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
310        library.
311    
312    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
313        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
314        is not the first non-POSIX option to be added. Clearly some people find
315        these options useful.
316    
317    17. If a caller to the POSIX matching function regexec() passes a non-zero
318        value for nmatch with a NULL value for pmatch, the value of
319        nmatch is forced to zero.
320    
321    18. RunGrepTest did not have a test for the availability of the -u option of
322        the diff command, as RunTest does. It now checks in the same way as
323        RunTest, and also checks for the -b option.
324    
325    19. If an odd number of negated classes containing just a single character
326        interposed, within parentheses, between a forward reference to a named
327        subpattern and the definition of the subpattern, compilation crashed with
328        an internal error, complaining that it could not find the referenced
329        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
330        [The bug was that it was starting one character too far in when skipping
331        over the character class, thus treating the ] as data rather than
332        terminating the class. This meant it could skip too much.]
333    
334    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
335        /g option in pcretest when the pattern contains \K, which makes it possible
336        to have an empty string match not at the start, even when the pattern is
337        anchored. Updated pcretest and pcredemo to use this option.
338    
339    21. If the maximum number of capturing subpatterns in a recursion was greater
340        than the maximum at the outer level, the higher number was returned, but
341        with unset values at the outer level. The correct (outer level) value is
342        now given.
343    
344    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
345        PCRE did not set those parentheses (unlike Perl). I have now found a way to
346        make it do so. The string so far is captured, making this feature
347        compatible with Perl.
348    
349    23. The tests have been re-organized, adding tests 11 and 12, to make it
350        possible to check the Perl 5.10 features against Perl 5.10.
351    
352    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
353        pattern matches a fixed length string. PCRE did not allow this; now it
354        does. Neither allows recursion.
355    
356    25. I finally figured out how to implement a request to provide the minimum
357        length of subject string that was needed in order to match a given pattern.
358        (It was back references and recursion that I had previously got hung up
359        on.) This code has now been added to pcre_study(); it finds a lower bound
360        to the length of subject needed. It is not necessarily the greatest lower
361        bound, but using it to avoid searching strings that are too short does give
362        some useful speed-ups. The value is available to calling programs via
363        pcre_fullinfo().
364    
365    26. While implementing 25, I discovered to my embarrassment that pcretest had
366        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
367        study optimizations had never been tested with that matching function.
368        Oops. What is worse, even when it was passed study data, there was a bug in
369        pcre_dfa_exec() that meant it never actually used it. Double oops. There
370        were also very few tests of studied patterns with pcre_dfa_exec().
371    
372    27. If (?| is used to create subpatterns with duplicate numbers, they are now
373        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
374        on the other side of the coin, they are no longer allowed to have different
375        names, because these cannot be distinguished in PCRE, and this has caused
376        confusion. (This is a difference from Perl.)
377    
378    28. When duplicate subpattern names are present (necessarily with different
379        numbers, as required by 27 above), and a test is made by name in a
380        conditional pattern, either for a subpattern having been matched, or for
381        recursion in such a pattern, all the associated numbered subpatterns are
382        tested, and the overall condition is true if the condition is true for any
383        one of them. This is the way Perl works, and is also more like the way
384        testing by number works.
385    
386    
387    Version 7.9 11-Apr-09
388    ---------------------
389    
390    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
391        (pcretest), all targets were linked against these libraries. This included
392        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
393        libraries. This caused unwanted dependencies to be created. This problem
394        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
395        pcretest is linked with readline.
396    
397    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
398        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
399        moved outside it again, because FALSE and TRUE are already defined in AIX,
400        but BOOL is not.
401    
402    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
403        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
404    
405    4.  The pcregrep documentation said spaces were inserted as well as colons (or
406        hyphens) following file names and line numbers when outputting matching
407        lines. This is not true; no spaces are inserted. I have also clarified the
408        wording for the --colour (or --color) option.
409    
410    5.  In pcregrep, when --colour was used with -o, the list of matching strings
411        was not coloured; this is different to GNU grep, so I have changed it to be
412        the same.
413    
414    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
415        each matching line was coloured. Now it goes on to look for further matches
416        of any of the test patterns, which is the same behaviour as GNU grep.
417    
418    7.  A pattern that could match an empty string could cause pcregrep to loop; it
419        doesn't make sense to accept an empty string match in pcregrep, so I have
420        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
421        seems to be how GNU grep behaves.
422    
423    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
424        start or after a newline", because the conditional assertion was not being
425        correctly handled. The rule now is that both the assertion and what follows
426        in the first alternative must satisfy the test.
427    
428    9.  If auto-callout was enabled in a pattern with a conditional group whose
429        condition was an assertion, PCRE could crash during matching, both with
430        pcre_exec() and pcre_dfa_exec().
431    
432    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
433        used for matching.
434    
435    11. Unicode property support in character classes was not working for
436        characters (bytes) greater than 127 when not in UTF-8 mode.
437    
438    12. Added the -M command line option to pcretest.
439    
440    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
441    
442    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
443    
444    16. Added comments and documentation about mis-use of no_arg in the C++
445        wrapper.
446    
447    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
448        from Martin Jerabek that uses macro names for all relevant character and
449        string constants.
450    
451    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
452        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
453        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
454        these, but not everybody uses configure.
455    
456    19. A conditional group that had only one branch was not being correctly
457        recognized as an item that could match an empty string. This meant that an
458        enclosing group might also not be so recognized, causing infinite looping
459        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
460        with the subject "ab", where knowledge that the repeated group can match
461        nothing is needed in order to break the loop.
462    
463    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
464        exec(), but without supplying a callout function, matching went wrong.
465    
466    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
467        leak if the size of the offset vector was greater than 30. When the vector
468        is smaller, the saved offsets during recursion go onto a local stack
469        vector, but for larger vectors malloc() is used. It was failing to free
470        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
471        error, in fact).
472    
473    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
474        heapframe that is used only when UTF-8 support is enabled. This caused no
475        problem, but was untidy.
476    
477    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
478        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
479        included within another project.
480    
481    24. Steven Van Ingelgem's patches to add more options to the CMake support,
482        slightly modified by me:
483    
484          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
485              not building pcregrep.
486    
487          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
488              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
489    
490    25. Forward references, both numeric and by name, in patterns that made use of
491        duplicate group numbers, could behave incorrectly or give incorrect errors,
492        because when scanning forward to find the reference group, PCRE was not
493        taking into account the duplicate group numbers. A pattern such as
494        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
495    
496    26. Changed a few more instances of "const unsigned char *" to USPTR, making
497        the feature of a custom pointer more persuasive (as requested by a user).
498    
499    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
500        pcretest.c, inside #ifndefs, because it seems they are sometimes already
501        pre-defined.
502    
503    28. Added support for (*UTF8) at the start of a pattern.
504    
505    29. Arrange for flags added by the "release type" setting in CMake to be shown
506        in the configuration summary.
507    
508    
509    Version 7.8 05-Sep-08
510    ---------------------
511    
512    1.  Replaced UCP searching code with optimized version as implemented for Ad
513        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
514        stage table and inline lookup instead of a function, giving speed ups of 2
515        to 5 times on some simple patterns that I tested. Permission was given to
516        distribute the MultiStage2.py script that generates the tables (it's not in
517        the tarball, but is in the Subversion repository).
518    
519    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
520        scripts.
521    
522    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
523        a group with a zero qualifier. The result of the study could be incorrect,
524        or the function might crash, depending on the pattern.
525    
526    4.  Caseless matching was not working for non-ASCII characters in back
527        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
528        It now works when Unicode Property Support is available.
529    
530    5.  In pcretest, an escape such as \x{de} in the data was always generating
531        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
532        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
533        truncation.
534    
535    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
536    
537    7.  Added two (int) casts to pcregrep when printing the difference of two
538        pointers, in case they are 64-bit values.
539    
540    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
541        test 2 if it fails.
542    
543    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
544        and a #define of that name to empty if it is not externally set. This is to
545        allow users of MSVC to set it if necessary.
546    
547    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
548        the convenience functions in the pcre_get.c source file.
549    
550    11. An option change at the start of a pattern that had top-level alternatives
551        could cause overwriting and/or a crash. This command provoked a crash in
552        some environments:
553    
554          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
555    
556        This potential security problem was recorded as CVE-2008-2371.
557    
558    12. For a pattern where the match had to start at the beginning or immediately
559        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
560        pcre_dfa_exec() could read past the end of the passed subject if there was
561        no match. To help with detecting such bugs (e.g. with valgrind), I modified
562        pcretest so that it places the subject at the end of its malloc-ed buffer.
563    
564    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
565        exec() might read past the end of the data buffer in UTF-8 mode.
566    
567    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
568        the data contained the byte 0x85 as part of a UTF-8 character within its
569        first line. This applied both to normal and DFA matching.
570    
571    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
572        /^[^d]*?$/8 failed to match "abc".
573    
574    16. Added a missing copyright notice to pcrecpp_internal.h.
575    
576    17. Make it more clear in the documentation that values returned from
577        pcre_exec() in ovector are byte offsets, not character counts.
578    
579    18. Tidied a few places to stop certain compilers from issuing warnings.
580    
581    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
582        supplied by Stefan Weber. I made a further small update for 7.8 because
583        there is a change of source arrangements: the pcre_searchfuncs.c module is
584        replaced by pcre_ucd.c.
585    
586    
587    Version 7.7 07-May-08
588    ---------------------
589    
590    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
591        a string to a long long, pretend we don't even have a long long." This is
592        done by checking for the strtoq, strtoll, and _strtoi64 functions.
593    
594    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
595        pre-7.6 versions, which defined a global no_arg variable instead of putting
596        it in the RE class. (See also #8 below.)
597    
598    3.  Remove a line of dead code, identified by coverity and reported by Nuno
599        Lopes.
600    
601    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
602    
603        (1) The include/exclude patterns were being applied to the whole pathnames
604            of files, instead of just to the final components.
605    
606        (2) If there was more than one level of directory, the subdirectories were
607            skipped unless they satisfied the include/exclude conditions. This is
608            inconsistent with GNU grep (and could even be seen as contrary to the
609            pcregrep specification - which I improved to make it absolutely clear).
610            The action now is always to scan all levels of directory, and just
611            apply the include/exclude patterns to regular files.
612    
613    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
614        --exclude_dir in the tests to avoid scanning .svn directories.
615    
616    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
617        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
618        doesn't support NULs in patterns.
619    
620    7.  Added some missing "const"s to declarations of static tables in
621        pcre_compile.c and pcre_dfa_exec.c.
622    
623    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
624        caused by fix #2  above. (Subsequently also a second patch to fix the
625        first patch. And a third patch - this was a messy problem.)
626    
627    9.  Applied Craig's patch to remove the use of push_back().
628    
629    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
630        matching function regexec().
631    
632    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
633        which, however, unlike Perl's \g{...}, are subroutine calls, not back
634        references. PCRE supports relative numbers with this syntax (I don't think
635        Oniguruma does).
636    
637    12. Previously, a group with a zero repeat such as (...){0} was completely
638        omitted from the compiled regex. However, this means that if the group
639        was called as a subroutine from elsewhere in the pattern, things went wrong
640        (an internal error was given). Such groups are now left in the compiled
641        pattern, with a new opcode that causes them to be skipped at execution
642        time.
643    
644    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
645        to the way PCRE behaves:
646    
647        (a) A lone ] character is dis-allowed (Perl treats it as data).
648    
649        (b) A back reference to an unmatched subpattern matches an empty string
650            (Perl fails the current match path).
651    
652        (c) A data ] in a character class must be notated as \] because if the
653            first data character in a class is ], it defines an empty class. (In
654            Perl it is not possible to have an empty class.) The empty class []
655            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
656            The negative empty class [^] matches any one character, independently
657            of the DOTALL setting.
658    
659    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
660        non-existent subpattern following a character class starting with ']' and
661        containing () gave an internal compiling error instead of "reference to
662        non-existent subpattern". Fortunately, when the pattern did exist, the
663        compiled code was correct. (When scanning forwards to check for the
664        existencd of the subpattern, it was treating the data ']' as terminating
665        the class, so got the count wrong. When actually compiling, the reference
666        was subsequently set up correctly.)
667    
668    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
669        it was being rejected as not supported by pcre_dfa_exec(), even though
670        other assertions are supported. I have made pcre_dfa_exec() support
671        (*FAIL).
672    
673    16. The implementation of 13c above involved the invention of a new opcode,
674        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
675        cannot be changed at match time, I realized I could make a small
676        improvement to matching performance by compiling OP_ALLANY instead of
677        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
678        on the OP_ANY path.
679    
680    17. Compiling pcretest on Windows with readline support failed without the
681        following two fixes: (1) Make the unistd.h include conditional on
682        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
683    
684    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
685        ncurses library to be included for pcretest when ReadLine support is
686        requested, but also to allow for it to be overridden. This patch came from
687        Daniel Bergström.
688    
689    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
690        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
691        any errors with the current Unicode tables. Thanks to Peter Kankowski for
692        spotting this.
693    
694    
695    Version 7.6 28-Jan-08
696    ---------------------
697    
698    1.  A character class containing a very large number of characters with
699        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
700        overflow.
701    
702    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
703        HAVE_LONG_LONG is not defined.
704    
705    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
706        bring them up to date and include new features. This patch includes:
707    
708        - Fixed PH's badly added libz and libbz2 support.
709        - Fixed a problem with static linking.
710        - Added pcredemo. [But later removed - see 7 below.]
711        - Fixed dftables problem and added an option.
712        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
713            HAVE_LONG_LONG.
714        - Added readline support for pcretest.
715        - Added an listing of the option settings after cmake has run.
716    
717    4.  A user submitted a patch to Makefile that makes it easy to create
718        "pcre.dll" under mingw when using Configure/Make. I added stuff to
719        Makefile.am that cause it to include this special target, without
720        affecting anything else. Note that the same mingw target plus all
721        the other distribution libraries and programs are now supported
722        when configuring with CMake (see 6 below) instead of with
723        Configure/Make.
724    
725    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
726        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
727        exported in the Windows port". It has not yet been confirmed that the patch
728        solves the problem, but it does no harm.
729    
730    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
731        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
732        with CMake, and also correct the comment about stack recursion.
733    
734    7.  Remove the automatic building of pcredemo from the ./configure system and
735        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
736        of a program that users should build themselves after PCRE is installed, so
737        building it automatically is not really right. What is more, it gave
738        trouble in some build environments.
739    
740    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
741    
742    
743    Version 7.5 10-Jan-08
744    ---------------------
745    
746    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
747        values in parens when parsing an RE using the C++ wrapper."
748    
749    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
750        Characters greater than 255 were excluded from the class instead of being
751        included.
752    
753    3.  The same bug as (2) above applied to negated POSIX classes such as
754        [:^space:].
755    
756    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
757        defined or documented. It seems to have been a typo for PCRE_STATIC, so
758        I have changed it.
759    
760    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
761        first named subpattern) and a construct such as (?&a) would reference the
762        first named subpattern whose name started with "a" (in other words, the
763        length check was missing). Both these problems are fixed. "Subpattern name
764        expected" is now given for (?&) (a zero-length name), and this patch also
765        makes it give the same error for \k'' (previously it complained that that
766        was a reference to a non-existent subpattern).
767    
768    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
769        this is right because (?- can be followed by option settings as well as by
770        digits. I have, however, made the messages clearer.
771    
772    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
773        than the number used in the conditional) now cause a compile-time error.
774        This is actually not compatible with Perl, which accepts such patterns, but
775        treats the conditional as always being FALSE (as PCRE used to), but it
776        seems to me that giving a diagnostic is better.
777    
778    8.  Change "alphameric" to the more common word "alphanumeric" in comments
779        and messages.
780    
781    9.  Fix two occurrences of "backslash" in comments that should have been
782        "backspace".
783    
784    10. Remove two redundant lines of code that can never be obeyed (their function
785        was moved elsewhere).
786    
787    11. The program that makes PCRE's Unicode character property table had a bug
788        which caused it to generate incorrect table entries for sequences of
789        characters that have the same character type, but are in different scripts.
790        It amalgamated them into a single range, with the script of the first of
791        them. In other words, some characters were in the wrong script. There were
792        thirteen such cases, affecting characters in the following ranges:
793    
794          U+002b0 - U+002c1
795          U+0060c - U+0060d
796          U+0061e - U+00612
797          U+0064b - U+0065e
798          U+0074d - U+0076d
799          U+01800 - U+01805
800          U+01d00 - U+01d77
801          U+01d9b - U+01dbf
802          U+0200b - U+0200f
803          U+030fc - U+030fe
804          U+03260 - U+0327f
805          U+0fb46 - U+0fbb1
806          U+10450 - U+1049d
807    
808    12. The -o option (show only the matching part of a line) for pcregrep was not
809        compatible with GNU grep in that, if there was more than one match in a
810        line, it showed only the first of them. It now behaves in the same way as
811        GNU grep.
812    
813    13. If the -o and -v options were combined for pcregrep, it printed a blank
814        line for every non-matching line. GNU grep prints nothing, and pcregrep now
815        does the same. The return code can be used to tell if there were any
816        non-matching lines.
817    
818    14. Added --file-offsets and --line-offsets to pcregrep.
819    
820    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
821        infinitely looping recursion. The bug was that positive lookaheads were not
822        being skipped when checking for a possible empty match (negative lookaheads
823        and both kinds of lookbehind were skipped).
824    
825    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
826        inclusion of <windows.h> to before rather than after the definition of
827        INVALID_FILE_ATTRIBUTES (patch from David Byron).
828    
829    17. Specifying a possessive quantifier with a specific limit for a Unicode
830        character property caused pcre_compile() to compile bad code, which led at
831        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
832        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
833        caused the error; without that there was no problem.
834    
835    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
836    
837    19. Added --enable-pcretest-libreadline.
838    
839    20. In pcrecpp.cc, the variable 'count' was incremented twice in
840        RE::GlobalReplace(). As a result, the number of replacements returned was
841        double what it should be. I removed one of the increments, but Craig sent a
842        later patch that removed the other one (the right fix) and added unit tests
843        that check the return values (which was not done before).
844    
845    21. Several CMake things:
846    
847        (1) Arranged that, when cmake is used on Unix, the libraries end up with
848            the names libpcre and libpcreposix, not just pcre and pcreposix.
849    
850        (2) The above change means that pcretest and pcregrep are now correctly
851            linked with the newly-built libraries, not previously installed ones.
852    
853        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
854    
855    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
856        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
857        UTF-8 newline character). The key issue is that the pattern starts .*;
858        this means that the match must be either at the beginning, or after a
859        newline. The bug was in the code for advancing after a failed match and
860        checking that the new position followed a newline. It was not taking
861        account of UTF-8 characters correctly.
862    
863    23. PCRE was behaving differently from Perl in the way it recognized POSIX
864        character classes. PCRE was not treating the sequence [:...:] as a
865        character class unless the ... were all letters. Perl, however, seems to
866        allow any characters between [: and :], though of course it rejects as
867        unknown any "names" that contain non-letters, because all the known class
868        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
869        for example, whereas PCRE did not - it did not recognize a POSIX character
870        class. This seemed a bit dangerous, so the code has been changed to be
871        closer to Perl. The behaviour is not identical to Perl, because PCRE will
872        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
873        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
874        Perl does, and where it didn't before.
875    
876    24. Rewrite so as to remove the single use of %n from pcregrep because in some
877        Windows environments %n is disabled by default.
878    
879    
880    Version 7.4 21-Sep-07
881    ---------------------
882    
883    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
884        means that a class such as [\s] counted as "explicit reference to CR or
885        LF". That isn't really right - the whole point of the change was to try to
886        help when there was an actual mention of one of the two characters. So now
887        the change happens only if \r or \n (or a literal CR or LF) character is
888        encountered.
889    
890    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
891        of both had grown to the point where there were only 3 bits left.
892        Fortunately, there was spare space in the data structure, and so I have
893        moved the internal flags into a new 16-bit field to free up more option
894        bits.
895    
896    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
897        but did not set the internal JCHANGED flag - either of these is enough to
898        control the way the "get" function works - but the PCRE_INFO_JCHANGED
899        facility is supposed to tell if (?J) was ever used, so now (?J) at the
900        start sets both bits.
901    
902    4.  Added options (at build time, compile time, exec time) to change \R from
903        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
904    
905    5.  doc/pcresyntax.html was missing from the distribution.
906    
907    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
908        compatibility, even though it is no longer used.
909    
910    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
911        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
912        windows.h file is present (where different names are used). [This was
913        reversed later after testing - see 16 below.]
914    
915    8.  Changed all #include <config.h> to #include "config.h". There were also
916        some further <pcre.h> cases that I changed to "pcre.h".
917    
918    9.  When pcregrep was used with the --colour option, it missed the line ending
919        sequence off the lines that it output.
920    
921    10. It was pointed out to me that arrays of string pointers cause lots of
922        relocations when a shared library is dynamically loaded. A technique of
923        using a single long string with a table of offsets can drastically reduce
924        these. I have refactored PCRE in four places to do this. The result is
925        dramatic:
926    
927          Originally:                          290
928          After changing UCP table:            187
929          After changing error message table:   43
930          After changing table of "verbs"       36
931          After changing table of Posix names   22
932    
933        Thanks to the folks working on Gregex for glib for this insight.
934    
935    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
936        unicode-properties was also set.
937    
938    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
939    
940    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
941        checked only for CRLF.
942    
943    14. Added casts to pcretest.c to avoid compiler warnings.
944    
945    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
946    
947    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
948        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
949        entirely. This removes changes made in 7 above.
950    
951    17. The CMake files have been updated, and there is now more information about
952        building with CMake in the NON-UNIX-USE document.
953    
954    
955    Version 7.3 28-Aug-07
956    ---------------------
957    
958     1. In the rejigging of the build system that eventually resulted in 7.1, the
959        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
960        brackets there is not right, since it causes compilers to look for an
961        installed pcre.h, not the version that is in the source that is being
962        compiled (which of course may be different). I have changed it back to:
963    
964          #include "pcre.h"
965    
966        I have a vague recollection that the change was concerned with compiling in
967        different directories, but in the new build system, that is taken care of
968        by the VPATH setting the Makefile.
969    
970     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
971        when the subject happened to end in the byte 0x85 (e.g. if the last
972        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
973        characters but of course it shouldn't be taken as a newline when it is part
974        of another character. The bug was that, for an unlimited repeat of . in
975        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
976        characters when looking for a newline.
977    
978     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
979    
980     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
981        in debug output.
982    
983     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
984        long printing in the pcrecpp unittest when running under MinGW.
985    
986     6. ESC_K was left out of the EBCDIC table.
987    
988     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
989        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
990        limit also applies to "virtual nesting" when a pattern is recursive, and in
991        this case 1000 isn't so big. I have been able to remove this limit at the
992        expense of backing off one optimization in certain circumstances. Normally,
993        when pcre_exec() would call its internal match() function recursively and
994        immediately return the result unconditionally, it uses a "tail recursion"
995        feature to save stack. However, when a subpattern that can match an empty
996        string has an unlimited repetition quantifier, it no longer makes this
997        optimization. That gives it a stack frame in which to save the data for
998        checking that an empty string has been matched. Previously this was taken
999        from the 1000-entry workspace that had been reserved. So now there is no
1000        explicit limit, but more stack is used.
1001    
1002     8. Applied Daniel's patches to solve problems with the import/export magic
1003        syntax that is required for Windows, and which was going wrong for the
1004        pcreposix and pcrecpp parts of the library. These were overlooked when this
1005        problem was solved for the main library.
1006    
1007     9. There were some crude static tests to avoid integer overflow when computing
1008        the size of patterns that contain repeated groups with explicit upper
1009        limits. As the maximum quantifier is 65535, the maximum group length was
1010        set at 30,000 so that the product of these two numbers did not overflow a
1011        32-bit integer. However, it turns out that people want to use groups that
1012        are longer than 30,000 bytes (though not repeat them that many times).
1013        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
1014        made it possible to implement the integer overflow checks in a much more
1015        dynamic way, which I have now done. The artificial limitation on group
1016        length has been removed - we now have only the limit on the total length of
1017        the compiled pattern, which depends on the LINK_SIZE setting.
1018    
1019    10. Fixed a bug in the documentation for get/copy named substring when
1020        duplicate names are permitted. If none of the named substrings are set, the
1021        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
1022        empty string.
1023    
1024    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
1025        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
1026        because the ] is interpreted as the first data character and the
1027        terminating ] is not found. PCRE has been made compatible with Perl in this
1028        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
1029        cause memory overwriting.
1030    
1031    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
1032        string has been matched (to stop an infinite loop). It was not recognizing
1033        a conditional subpattern that could match an empty string if that
1034        subpattern was within another subpattern. For example, it looped when
1035        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
1036        condition was not nested. This bug has been fixed.
1037    
1038    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
1039        past the start of the subject in the presence of bytes with the top bit
1040        set, for example "\x8aBCD".
1041    
1042    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
1043        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
1044    
1045    14. Optimized (?!) to (*FAIL).
1046    
1047    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
1048        This restricts code points to be within the range 0 to 0x10FFFF, excluding
1049        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
1050        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
1051        does: it's just the validity check that is more restrictive.
1052    
1053    16. Inserted checks for integer overflows during escape sequence (backslash)
1054        processing, and also fixed erroneous offset values for syntax errors during
1055        backslash processing.
1056    
1057    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
1058        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
1059    
1060    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
1061        caused an overrun.
1062    
1063    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
1064        something other than just ASCII characters) inside a group that had an
1065        unlimited repeat caused a loop at compile time (while checking to see
1066        whether the group could match an empty string).
1067    
1068    20. Debugging a pattern containing \p or \P could cause a crash. For example,
1069        [\P{Any}] did so. (Error in the code for printing property names.)
1070    
1071    21. An orphan \E inside a character class could cause a crash.
1072    
1073    22. A repeated capturing bracket such as (A)? could cause a wild memory
1074        reference during compilation.
1075    
1076    23. There are several functions in pcre_compile() that scan along a compiled
1077        expression for various reasons (e.g. to see if it's fixed length for look
1078        behind). There were bugs in these functions when a repeated \p or \P was
1079        present in the pattern. These operators have additional parameters compared
1080        with \d, etc, and these were not being taken into account when moving along
1081        the compiled data. Specifically:
1082    
1083        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
1084            length.
1085    
1086        (b) An item such as \pL+ within a repeated group could cause crashes or
1087            loops.
1088    
1089        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
1090            "reference to non-existent subpattern" error.
1091    
1092        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
1093    
1094    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
1095        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
1096    
1097    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
1098    
1099    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
1100        character were causing crashes (broken optimization).
1101    
1102    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
1103        \p or \P) caused a compile-time loop.
1104    
1105    28. More problems have arisen in unanchored patterns when CRLF is a valid line
1106        break. For example, the unstudied pattern [\r\n]A does not match the string
1107        "\r\nA" because change 7.0/46 below moves the current point on by two
1108        characters after failing to match at the start. However, the pattern \nA
1109        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
1110        the same is true. There doesn't seem any very clean way out of this, but
1111        what I have chosen to do makes the common cases work: PCRE now takes note
1112        of whether there can be an explicit match for \r or \n anywhere in the
1113        pattern, and if so, 7.0/46 no longer applies. As part of this change,
1114        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
1115        pattern has explicit CR or LF references.
1116    
1117    29. Added (*CR) etc for changing newline setting at start of pattern.
1118    
1119    
1120    Version 7.2 19-Jun-07
1121    ---------------------
1122    
1123     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
1124        which is apparently normally available under Windows.
1125    
1126     2. Re-jig the pcregrep tests with different newline settings in an attempt
1127        to make them independent of the local environment's newline setting.
1128    
1129     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
1130    
1131     4. Some of the "internals" tests were previously cut out when the link size
1132        was not 2, because the output contained actual offsets. The recent new
1133        "Z" feature of pcretest means that these can be cut out, making the tests
1134        usable with all link sizes.
1135    
1136     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
1137        stack recursion. This gives a massive performance boost under BSD, but just
1138        a small improvement under Linux. However, it saves one field in the frame
1139        in all cases.
1140    
1141     6. Added more features from the forthcoming Perl 5.10:
1142    
1143        (a) (?-n) (where n is a string of digits) is a relative subroutine or
1144            recursion call. It refers to the nth most recently opened parentheses.
1145    
1146        (b) (?+n) is also a relative subroutine call; it refers to the nth next
1147            to be opened parentheses.
1148    
1149        (c) Conditions that refer to capturing parentheses can be specified
1150            relatively, for example, (?(-2)... or (?(+3)...
1151    
1152        (d) \K resets the start of the current match so that everything before
1153            is not part of it.
1154    
1155        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
1156    
1157        (f) \g{name} is another synonym - part of Perl 5.10's unification of
1158            reference syntax.
1159    
1160        (g) (?| introduces a group in which the numbering of parentheses in each
1161            alternative starts with the same number.
1162    
1163        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
1164    
1165     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
1166        PCRE_INFO_JCHANGED.
1167    
1168     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
1169        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
1170        for detecting groups that can match an empty string.
1171    
1172     9. A pattern with a very large number of alternatives (more than several
1173        hundred) was running out of internal workspace during the pre-compile
1174        phase, where pcre_compile() figures out how much memory will be needed. A
1175        bit of new cunning has reduced the workspace needed for groups with
1176        alternatives. The 1000-alternative test pattern now uses 12 bytes of
1177        workspace instead of running out of the 4096 that are available.
1178    
1179    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
1180    
1181    11. Applied patch from Google to remove an optimization that didn't quite work.
1182        The report of the bug said:
1183    
1184          pcrecpp::RE("a*").FullMatch("aaa") matches, while
1185          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
1186          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
1187    
1188    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
1189        it matched the wrong number of bytes.
1190    
1191    
1192    Version 7.1 24-Apr-07
1193    ---------------------
1194    
1195     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
1196        that is more "standard", making use of automake and other Autotools. There
1197        is some re-arrangement of the files and adjustment of comments consequent
1198        on this.
1199    
1200     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
1201        for recursive directory scanning broke on some systems because the files
1202        are not scanned in any specific order and on different systems the order
1203        was different. A call to "sort" has been inserted into RunGrepTest for the
1204        approprate test as a short-term fix. In the longer term there may be an
1205        alternative.
1206    
1207     3. I had an email from Eric Raymond about problems translating some of PCRE's
1208        man pages to HTML (despite the fact that I distribute HTML pages, some
1209        people do their own conversions for various reasons). The problems
1210        concerned the use of low-level troff macros .br and .in. I have therefore
1211        removed all such uses from the man pages (some were redundant, some could
1212        be replaced by .nf/.fi pairs). The 132html script that I use to generate
1213        HTML has been updated to handle .nf/.fi and to complain if it encounters
1214        .br or .in.
1215    
1216     4. Updated comments in configure.ac that get placed in config.h.in and also
1217        arranged for config.h to be included in the distribution, with the name
1218        config.h.generic, for the benefit of those who have to compile without
1219        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
1220    
1221     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
1222        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
1223        makevp.bat for the current PCRE, using the additional files
1224        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
1225    
1226     6. A Windows user reported a minor discrepancy with test 2, which turned out
1227        to be caused by a trailing space on an input line that had got lost in his
1228        copy. The trailing space was an accident, so I've just removed it.
1229    
1230     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
1231        that is needed.
1232    
1233     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
1234        as "const" (a) because they are and (b) because it helps the PHP
1235        maintainers who have recently made a script to detect big data structures
1236        in the php code that should be moved to the .rodata section. I remembered
1237        to update Builducptable as well, so it won't revert if ucptable.h is ever
1238        re-created.
1239    
1240     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
1241        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
1242        order to be able to cut out the UTF-8 tables in the latter when UTF-8
1243        support is not required. This saves 1.5-2K of code, which is important in
1244        some applications.
1245    
1246        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
1247        so as not to refer to the tables, even though these functions will never be
1248        called when UTF-8 support is disabled. Otherwise there are problems with a
1249        shared library.
1250    
1251    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
1252    
1253        (a) It was defining its arguments as char * instead of void *.
1254    
1255        (b) It was assuming that all moves were upwards in memory; this was true
1256            a long time ago when I wrote it, but is no longer the case.
1257    
1258        The emulated memove() is provided for those environments that have neither
1259        memmove() nor bcopy(). I didn't think anyone used it these days, but that
1260        is clearly not the case, as these two bugs were recently reported.
1261    
1262    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
1263        and Detrail to create the HTML documentation, the .txt form of the man
1264        pages, and it removes trailing spaces from listed files. It also creates
1265        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
1266        case, it wraps all the #defines with #ifndefs. This script should be run
1267        before "make dist".
1268    
1269    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
1270        with Unicode property support.
1271    
1272        (a) For a maximizing quantifier, if the two different cases of the
1273            character were of different lengths in their UTF-8 codings (there are
1274            some cases like this - I found 11), and the matching function had to
1275            back up over a mixture of the two cases, it incorrectly assumed they
1276            were both the same length.
1277    
1278        (b) When PCRE was configured to use the heap rather than the stack for
1279            recursion during matching, it was not correctly preserving the data for
1280            the other case of a UTF-8 character when checking ahead for a match
1281            while processing a minimizing repeat. If the check also involved
1282            matching a wide character, but failed, corruption could cause an
1283            erroneous result when trying to check for a repeat of the original
1284            character.
1285    
1286    13. Some tidying changes to the testing mechanism:
1287    
1288        (a) The RunTest script now detects the internal link size and whether there
1289            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
1290            values substituted by "configure". (The RunGrepTest script already did
1291            this for UTF-8.) The configure.ac script no longer substitutes the
1292            relevant variables.
1293    
1294        (b) The debugging options /B and /D in pcretest show the compiled bytecode
1295            with length and offset values. This means that the output is different
1296            for different internal link sizes. Test 2 is skipped for link sizes
1297            other than 2 because of this, bypassing the problem. Unfortunately,
1298            there was also a test in test 3 (the locale tests) that used /B and
1299            failed for link sizes other than 2. Rather than cut the whole test out,
1300            I have added a new /Z option to pcretest that replaces the length and
1301            offset values with spaces. This is now used to make test 3 independent
1302            of link size. (Test 2 will be tidied up later.)
1303    
1304    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
1305        segmentation fault instead of returning the appropriate error message.
1306    
1307    15. In multiline mode when the newline sequence was set to "any", the pattern
1308        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
1309        This doesn't seem right; it now treats the CRLF combination as the line
1310        ending, and so does not match in that case. It's only a pattern such as ^$
1311        that would hit this one: something like ^ABC$ would have failed after \r
1312        and then tried again after \r\n.
1313    
1314    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
1315        in an attempt to make files that differ only in their line terminators
1316        compare equal. This works on Linux.
1317    
1318    17. Under certain error circumstances pcregrep might try to free random memory
1319        as it exited. This is now fixed, thanks to valgrind.
1320    
1321    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
1322        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
1323        was because its rules for how to advance for /g after matching an empty
1324        string at the end of a line did not allow for this case. They now check for
1325        it specially.
1326    
1327    20. pcretest is supposed to handle patterns and data of any length, by
1328        extending its buffers when necessary. It was getting this wrong when the
1329        buffer for a data line had to be extended.
1330    
1331    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
1332        CRLF as a newline sequence.
1333    
1334    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
1335        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
1336        I have nevertheless tidied it up.
1337    
1338    23. Added some casts to kill warnings from HP-UX ia64 compiler.
1339    
1340    24. Added a man page for pcre-config.
1341    
1342    
1343    Version 7.0 19-Dec-06
1344    ---------------------
1345    
1346     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
1347        moving to gcc 4.1.1.
1348    
1349     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1350        sys/time.h, which is documented as needed for this function. It doesn't
1351        seem to matter on Linux, but it showed up on some releases of OS X.
1352    
1353     3. It seems that there are systems where bytes whose values are greater than
1354        127 match isprint() in the "C" locale. The "C" locale should be the
1355        default when a C program starts up. In most systems, only ASCII printing
1356        characters match isprint(). This difference caused the output from pcretest
1357        to vary, making some of the tests fail. I have changed pcretest so that:
1358    
1359        (a) When it is outputting text in the compiled version of a pattern, bytes
1360            other than 32-126 are always shown as hex escapes.
1361    
1362        (b) When it is outputting text that is a matched part of a subject string,
1363            it does the same, unless a different locale has been set for the match
1364            (using the /L modifier). In this case, it uses isprint() to decide.
1365    
1366     4. Fixed a major bug that caused incorrect computation of the amount of memory
1367        required for a compiled pattern when options that changed within the
1368        pattern affected the logic of the preliminary scan that determines the
1369        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1370        that the computed length was too small. The symptoms of this bug were
1371        either the PCRE error "internal error: code overflow" from pcre_compile(),
1372        or a glibc crash with a message such as "pcretest: free(): invalid next
1373        size (fast)". Examples of patterns that provoked this bug (shown in
1374        pcretest format) are:
1375    
1376          /(?-x: )/x
1377          /(?x)(?-x: \s*#\s*)/
1378          /((?i)[\x{c0}])/8
1379          /(?i:[\x{c0}])/8
1380    
1381        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1382        is now done differently.
1383    
1384     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1385        wrapper classes; (b) implement a new function in the C++ scanner that is
1386        more efficient than the old way of doing things because it avoids levels of
1387        recursion in the regex matching; (c) add a paragraph to the documentation
1388        for the FullMatch() function.
1389    
1390     6. The escape sequence \n was being treated as whatever was defined as
1391        "newline". Not only was this contrary to the documentation, which states
1392        that \n is character 10 (hex 0A), but it also went horribly wrong when
1393        "newline" was defined as CRLF. This has been fixed.
1394    
1395     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1396        was being set to -1 for the "end of line" case (supposedly a value that no
1397        character can have). Though this value is never used (the check for end of
1398        line is "zero bytes in current character"), it caused compiler complaints.
1399        I've changed it to 0xffffffff.
1400    
1401     8. In pcre_version.c, the version string was being built by a sequence of
1402        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1403        string (as it is for production releases) called a macro with an empty
1404        argument. The C standard says the result of this is undefined. The gcc
1405        compiler treats it as an empty string (which was what was wanted) but it is
1406        reported that Visual C gives an error. The source has been hacked around to
1407        avoid this problem.
1408    
1409     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1410        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1411        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1412        of them did).
1413    
1414    10. Originally, pcretest opened its input and output without "b"; then I was
1415        told that "b" was needed in some environments, so it was added for release
1416        5.0 to both the input and output. (It makes no difference on Unix-like
1417        systems.) Later I was told that it is wrong for the input on Windows. I've
1418        now abstracted the modes into two macros, to make it easier to fiddle with
1419        them, and removed "b" from the input mode under Windows.
1420    
1421    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1422    
1423    12. Added -help and --help to pcretest as an official way of being reminded
1424        of the options.
1425    
1426    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1427        and pcrecpp.cc because they annoy compilers at high warning levels.
1428    
1429    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1430    
1431    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1432        scripts are not C programs :-) and which was not noticed because it works
1433        on Linux.
1434    
1435    16. pcretest is supposed to handle any length of pattern and data line (as one
1436        line or as a continued sequence of lines) by extending its input buffer if
1437        necessary. This feature was broken for very long pattern lines, leading to
1438        a string of junk being passed to pcre_compile() if the pattern was longer
1439        than about 50K.
1440    
1441    17. I have done a major re-factoring of the way pcre_compile() computes the
1442        amount of memory needed for a compiled pattern. Previously, there was code
1443        that made a preliminary scan of the pattern in order to do this. That was
1444        OK when PCRE was new, but as the facilities have expanded, it has become
1445        harder and harder to keep it in step with the real compile phase, and there
1446        have been a number of bugs (see for example, 4 above). I have now found a
1447        cunning way of running the real compile function in a "fake" mode that
1448        enables it to compute how much memory it would need, while actually only
1449        ever using a few hundred bytes of working memory and without too many
1450        tests of the mode. This should make future maintenance and development
1451        easier. A side effect of this work is that the limit of 200 on the nesting
1452        depth of parentheses has been removed (though this was never a serious
1453        limitation, I suspect). However, there is a downside: pcre_compile() now
1454        runs more slowly than before (30% or more, depending on the pattern). I
1455        hope this isn't a big issue. There is no effect on runtime performance.
1456    
1457    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1458        newline (only possible for the last line of a file) and it was a
1459        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1460    
1461    19. Added additional timing features to pcretest. (1) The -tm option now times
1462        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1463        separate command line item, by a number that specifies the number of
1464        repeats to use when timing. The default is 50000; this gives better
1465        precision, but takes uncomfortably long for very large patterns.
1466    
1467    20. Extended pcre_study() to be more clever in cases where a branch of a
1468        subpattern has no definite first character. For example, (a*|b*)[cd] would
1469        previously give no result from pcre_study(). Now it recognizes that the
1470        first character must be a, b, c, or d.
1471    
1472    21. There was an incorrect error "recursive call could loop indefinitely" if
1473        a subpattern (or the entire pattern) that was being tested for matching an
1474        empty string contained only one non-empty item after a nested subpattern.
1475        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1476        incorrectly, because the \d was being skipped in the check.
1477    
1478    22. The pcretest program now has a new pattern option /B and a command line
1479        option -b, which is equivalent to adding /B to every pattern. This causes
1480        it to show the compiled bytecode, without the additional information that
1481        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1482        is the same as /B/I).
1483    
1484    23. A new optimization is now able automatically to treat some sequences such
1485        as a*b as a*+b. More specifically, if something simple (such as a character
1486        or a simple class like \d) has an unlimited quantifier, and is followed by
1487        something that cannot possibly match the quantified thing, the quantifier
1488        is automatically "possessified".
1489    
1490    24. A recursive reference to a subpattern whose number was greater than 39
1491        went wrong under certain circumstances in UTF-8 mode. This bug could also
1492        have affected the operation of pcre_study().
1493    
1494    25. Realized that a little bit of performance could be had by replacing
1495        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1496    
1497    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1498    
1499    27. Possessive quantifiers such as a++ were previously implemented by turning
1500        them into atomic groups such as ($>a+). Now they have their own opcodes,
1501        which improves performance. This includes the automatically created ones
1502        from 23 above.
1503    
1504    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1505        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1506        the first matched character to be a colon. This applied both to named and
1507        numbered groups.
1508    
1509    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1510    
1511    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1512        building PCRE on Windows easier, so I have included it in the distribution.
1513    
1514    31. There is now a check in pcretest against a ridiculously large number being
1515        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1516        loop, the loop is abandoned.
1517    
1518    32. Forward references to subpatterns in conditions such as (?(2)...) where
1519        subpattern 2 is defined later cause pcre_compile() to search forwards in
1520        the pattern for the relevant set of parentheses. This search went wrong
1521        when there were unescaped parentheses in a character class, parentheses
1522        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1523    
1524    33. "Subroutine" calls and backreferences were previously restricted to
1525        referencing subpatterns earlier in the regex. This restriction has now
1526        been removed.
1527    
1528    34. Added a number of extra features that are going to be in Perl 5.10. On the
1529        whole, these are just syntactic alternatives for features that PCRE had
1530        previously implemented using the Python syntax or my own invention. The
1531        other formats are all retained for compatibility.
1532    
1533        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1534            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1535            also .NET compatible.
1536    
1537        (b) A recursion or subroutine call to a named group can now be defined as
1538            (?&name) as well as (?P>name).
1539    
1540        (c) A backreference to a named group can now be defined as \k<name> or
1541            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1542            5.10, are also .NET compatible.
1543    
1544        (d) A conditional reference to a named group can now use the syntax
1545            (?(<name>) or (?('name') as well as (?(name).
1546    
1547        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1548            groups (named and numbered) that are never evaluated inline, but can be
1549            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1550            is always false. There may be only one alternative in such a group.
1551    
1552        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1553            as the simple (?(R). The condition is true only if the most recent
1554            recursion is that of the given number or name. It does not search out
1555            through the entire recursion stack.
1556    
1557        (g) The escape \gN or \g{N} has been added, where N is a positive or
1558            negative number, specifying an absolute or relative reference.
1559    
1560    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1561        some "unreachable code" warnings.
1562    
1563    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1564        things, this adds five new scripts.
1565    
1566    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1567        There were also incompatibilities regarding the handling of \Q..\E inside
1568        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1569        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1570    
1571    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1572        matches an empty string, and forcibly breaks the loop. There were bugs in
1573        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1574        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1575        separate and independent bugs (that affected different cases) have been
1576        fixed.
1577    
1578    39. Refactored the code to abolish the use of different opcodes for small
1579        capturing bracket numbers. This is a tidy that I avoided doing when I
1580        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1581        The new approach is not only tidier, it makes it possible to reduce the
1582        memory needed to fix the previous bug (38).
1583    
1584    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1585        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1586        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1587        mode.
1588    
1589    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1590        report.
1591    
1592    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1593        copy construction and assignment in the C++ wrapper.
1594    
1595    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1596        couple of bugs that could have given wrong results in the "--newline=crlf"
1597        case.
1598    
1599    44. Added a number of casts and did some reorganization of signed/unsigned int
1600        variables following suggestions from Dair Grant. Also renamed the variable
1601        "this" as "item" because it is a C++ keyword.
1602    
1603    45. Arranged for dftables to add
1604    
1605          #include "pcre_internal.h"
1606    
1607        to pcre_chartables.c because without it, gcc 4.x may remove the array
1608        definition from the final binary if PCRE is built into a static library and
1609        dead code stripping is activated.
1610    
1611    46. For an unanchored pattern, if a match attempt fails at the start of a
1612        newline sequence, and the newline setting is CRLF or ANY, and the next two
1613        characters are CRLF, advance by two characters instead of one.
1614    
1615    
1616    Version 6.7 04-Jul-06
1617    ---------------------
1618    
1619     1. In order to handle tests when input lines are enormously long, pcretest has
1620        been re-factored so that it automatically extends its buffers when
1621        necessary. The code is crude, but this _is_ just a test program. The
1622        default size has been increased from 32K to 50K.
1623    
1624     2. The code in pcre_study() was using the value of the re argument before
1625        testing it for NULL. (Of course, in any sensible call of the function, it
1626        won't be NULL.)
1627    
1628     3. The memmove() emulation function in pcre_internal.h, which is used on
1629        systems that lack both memmove() and bcopy() - that is, hardly ever -
1630        was missing a "static" storage class specifier.
1631    
1632     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1633        containing an extended class (one that cannot be represented by a bitmap
1634        because it contains high-valued characters or Unicode property items, e.g.
1635        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1636        pattern, but PCRE should not loop if you do not (it no longer does).
1637        [Detail: two cases were found: (a) a repeated subpattern containing an
1638        extended class; (b) a recursive reference to a subpattern that followed a
1639        previous extended class. It wasn't skipping over the extended class
1640        correctly when UTF-8 mode was not set.]
1641    
1642     5. A negated single-character class was not being recognized as fixed-length
1643        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1644        compile error "lookbehind assertion is not fixed length".
1645    
1646     6. The RunPerlTest auxiliary script was showing an unexpected difference
1647        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1648        write a Perl script that can interpret lines of an input file either as
1649        byte characters or as UTF-8, which is what "perltest" was being required to
1650        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1651        can't do is switch easily at run time between having the "use utf8;" pragma
1652        or not. In the end, I fudged it by using the RunPerlTest script to insert
1653        "use utf8;" explicitly for the UTF-8 tests.
1654    
1655     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1656        the end of the subject string, contrary to the documentation and to what
1657        Perl does. This was true of both matching functions. Now it matches only at
1658        the start of the subject and immediately after *internal* newlines.
1659    
1660     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1661        a pointer to an int instead of a pointer to an unsigned long int. This
1662        caused problems on 64-bit systems.
1663    
1664     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1665        instance of the 'standard' template library not being so standard".
1666    
1667    10. There was no check on the number of named subpatterns nor the maximum
1668        length of a subpattern name. The product of these values is used to compute
1669        the size of the memory block for a compiled pattern. By supplying a very
1670        long subpattern name and a large number of named subpatterns, the size
1671        computation could be caused to overflow. This is now prevented by limiting
1672        the length of names to 32 characters, and the number of named subpatterns
1673        to 10,000.
1674    
1675    11. Subpatterns that are repeated with specific counts have to be replicated in
1676        the compiled pattern. The size of memory for this was computed from the
1677        length of the subpattern and the repeat count. The latter is limited to
1678        65535, but there was no limit on the former, meaning that integer overflow
1679        could in principle occur. The compiled length of a repeated subpattern is
1680        now limited to 30,000 bytes in order to prevent this.
1681    
1682    12. Added the optional facility to have named substrings with the same name.
1683    
1684    13. Added the ability to use a named substring as a condition, using the
1685        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1686        are numbers (not recommended). Forward references are permitted.
1687    
1688    14. Added forward references in named backreferences (if you see what I mean).
1689    
1690    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1691        pattern could run off the end of the subject. For example, the pattern
1692        "(?s)(.{1,5})"8 did this with the subject "ab".
1693    
1694    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1695        PCRE_CASELESS was set when matching characters that were quantified with ?
1696        or *.
1697    
1698    17. A character class other than a single negated character that had a minimum
1699        but no maximum quantifier - for example [ab]{6,} - was not handled
1700        correctly by pce_dfa_exec(). It would match only one character.
1701    
1702    18. A valid (though odd) pattern that looked like a POSIX character
1703        class but used an invalid character after [ (for example [[,abc,]]) caused
1704        pcre_compile() to give the error "Failed: internal error: code overflow" or
1705        in some cases to crash with a glibc free() error. This could even happen if
1706        the pattern terminated after [[ but there just happened to be a sequence of
1707        letters, a binary zero, and a closing ] in the memory that followed.
1708    
1709    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1710        over the years. Originally (before any Unicode support), just the bottom 8
1711        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1712        output from "man perlunicode" includes this:
1713    
1714          The regular expression compiler produces polymorphic opcodes.  That
1715          is, the pattern adapts to the data and automatically switches to
1716          the Unicode character scheme when presented with Unicode data--or
1717          instead uses a traditional byte scheme when presented with byte
1718          data.
1719    
1720        Sadly, a wide octal escape does not cause a switch, and in a string with
1721        no other multibyte characters, these octal escapes are treated as before.
1722        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1723        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1724        Unicode string.
1725    
1726        I have not perpetrated such confusion in PCRE. Up till now, it took just
1727        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1728        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1729        translate to the appropriate multibyte character.
1730    
1731    29. Applied some refactoring to reduce the number of warnings from Microsoft
1732        and Borland compilers. This has included removing the fudge introduced
1733        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1734        a warning about an unused variable.
1735    
1736    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1737        characters since release 4.0, because Perl (from release 5.004) does not.
1738        [Or at least, is documented not to: some releases seem to be in conflict
1739        with the documentation.] However, when a pattern was studied with
1740        pcre_study() and all its branches started with \s, PCRE still included VT
1741        as a possible starting character. Of course, this did no harm; it just
1742        caused an unnecessary match attempt.
1743    
1744    22. Removed a now-redundant internal flag bit that recorded the fact that case
1745        dependency changed within the pattern. This was once needed for "required
1746        byte" processing, but is no longer used. This recovers a now-scarce options
1747        bit. Also moved the least significant internal flag bit to the most-
1748        significant bit of the word, which was not previously used (hangover from
1749        the days when it was an int rather than a uint) to free up another bit for
1750        the future.
1751    
1752    23. Added support for CRLF line endings as well as CR and LF. As well as the
1753        default being selectable at build time, it can now be changed at runtime
1754        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1755        specify that it is scanning data with non-default line endings.
1756    
1757    24. Changed the definition of CXXLINK to make it agree with the definition of
1758        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1759    
1760    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1761        recursions. This makes a big different to stack usage for some patterns.
1762    
1763    26. If a subpattern containing a named recursion or subroutine reference such
1764        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1765        the space required for the compiled pattern went wrong and gave too small a
1766        value. Depending on the environment, this could lead to "Failed: internal
1767        error: code overflow at offset 49" or "glibc detected double free or
1768        corruption" errors.
1769    
1770    27. Applied patches from Google (a) to support the new newline modes and (b) to
1771        advance over multibyte UTF-8 characters in GlobalReplace.
1772    
1773    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1774        difference for some implementation of PCRE in some Windows version.
1775    
1776    29. Added some extra testing facilities to pcretest:
1777    
1778        \q<number>   in a data line sets the "match limit" value
1779        \Q<number>   in a data line sets the "match recursion limt" value
1780        -S <number>  sets the stack size, where <number> is in megabytes
1781    
1782        The -S option isn't available for Windows.
1783    
1784    
1785    Version 6.6 06-Feb-06
1786    ---------------------
1787    
1788     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1789        in pcreposix.h. I have copied the definition from pcre.h.
1790    
1791     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1792        because pcre.h is no longer a built file.
1793    
1794     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1795        not normally included in the compiled code.
1796    
1797    
1798    Version 6.5 01-Feb-06
1799    ---------------------
1800    
1801     1. When using the partial match feature with pcre_dfa_exec(), it was not
1802        anchoring the second and subsequent partial matches at the new starting
1803        point. This could lead to incorrect results. For example, with the pattern
1804        /1234/, partially matching against "123" and then "a4" gave a match.
1805    
1806     2. Changes to pcregrep:
1807    
1808        (a) All non-match returns from pcre_exec() were being treated as failures
1809            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1810            error message is output. Some extra information is given for the
1811            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1812            probably the only errors that are likely to be caused by users (by
1813            specifying a regex that has nested indefinite repeats, for instance).
1814            If there are more than 20 of these errors, pcregrep is abandoned.
1815    
1816        (b) A binary zero was treated as data while matching, but terminated the
1817            output line if it was written out. This has been fixed: binary zeroes
1818            are now no different to any other data bytes.
1819    
1820        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1821            used to set a locale for matching. The --locale=xxxx long option has
1822            been added (no short equivalent) to specify a locale explicitly on the
1823            pcregrep command, overriding the environment variables.
1824    
1825        (d) When -B was used with -n, some line numbers in the output were one less
1826            than they should have been.
1827    
1828        (e) Added the -o (--only-matching) option.
1829    
1830        (f) If -A or -C was used with -c (count only), some lines of context were
1831            accidentally printed for the final match.
1832    
1833        (g) Added the -H (--with-filename) option.
1834    
1835        (h) The combination of options -rh failed to suppress file names for files
1836            that were found from directory arguments.
1837    
1838        (i) Added the -D (--devices) and -d (--directories) options.
1839    
1840        (j) Added the -F (--fixed-strings) option.
1841    
1842        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1843    
1844        (l) Added the --colo(u)r option.
1845    
1846        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1847            is not present by default.
1848    
1849     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1850        items such as (?R) or (?1), when the recursion could match a number of
1851        alternatives. If it matched one of the alternatives, but subsequently,
1852        outside the recursion, there was a failure, the code tried to back up into
1853        the recursion. However, because of the way PCRE is implemented, this is not
1854        possible, and the result was an incorrect result from the match.
1855    
1856        In order to prevent this happening, the specification of recursion has
1857        been changed so that all such subpatterns are automatically treated as
1858        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1859    
1860     4. I had overlooked the fact that, in some locales, there are characters for
1861        which isalpha() is true but neither isupper() nor islower() are true. In
1862        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1863        and ordfeminine) are like this. This affected the treatment of \w and \W
1864        when they appeared in character classes, but not when they appeared outside
1865        a character class. The bit map for "word" characters is now created
1866        separately from the results of isalnum() instead of just taking it from the
1867        upper, lower, and digit maps. (Plus the underscore character, of course.)
1868    
1869     5. The above bug also affected the handling of POSIX character classes such as
1870        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1871        permanent tables. Instead, the bit maps for such a class were previously
1872        created as the appropriate unions of the upper, lower, and digit bitmaps.
1873        Now they are created by subtraction from the [[:word:]] class, which has
1874        its own bitmap.
1875    
1876     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1877        It is created by subtracting the vertical space characters (\x09, \x0a,
1878        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1879        subtraction was done in the overall bitmap for a character class, meaning
1880        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1881        be recognized. This bug has been fixed.
1882    
1883     7. Patches from the folks at Google:
1884    
1885          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1886          real life, but is still worth protecting against".
1887    
1888          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1889          regular expressions".
1890    
1891          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1892          have it.
1893    
1894          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1895          "configure" and the latter not, in order to fix a problem somebody had
1896          with compiling the Arg class on HP-UX.
1897    
1898          (e) Improve the error-handling of the C++ wrapper a little bit.
1899    
1900          (f) New tests for checking recursion limiting.
1901    
1902     8. The pcre_memmove() function, which is used only if the environment does not
1903        have a standard memmove() function (and is therefore rarely compiled),
1904        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1905        returning a result (though PCRE never actually uses the result).
1906    
1907     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1908        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1909        returned instead of calling malloc() with an overflowing number that would
1910        most likely cause subsequent chaos.
1911    
1912    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1913    
1914    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1915        with this option is matched, the nmatch and pmatch options of regexec() are
1916        ignored.
1917    
1918    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1919        provided in case anyone wants to the the POSIX interface with UTF-8
1920        strings.
1921    
1922    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1923        C++ linking (needed for some HP-UX environments).
1924    
1925    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1926        (unused parameter) and in the pcre_printint() function (omitted "default"
1927        switch label when the default is to do nothing).
1928    
1929    15. Added some code to make it possible, when PCRE is compiled as a C++
1930        library, to replace subject pointers for pcre_exec() with a smart pointer
1931        class, thus making it possible to process discontinuous strings.
1932    
1933    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1934        much the same function. They were added by different people who were trying
1935        to make PCRE easy to compile on non-Unix systems. It has been suggested
1936        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1937        for compiling on Windows systems. I have therefore replaced it with
1938        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1939        defaults to "extern" for C or "extern C" for C++, which works fine on
1940        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1941        SCOPE with something explicit in config.h. In addition:
1942    
1943        (a) pcreposix.h still had just "extern" instead of either of these macros;
1944            I have replaced it with PCRE_DATA_SCOPE.
1945    
1946        (b) Functions such as _pcre_xclass(), which are internal to the library,
1947            but external in the C sense, all had PCRE_EXPORT in their definitions.
1948            This is apparently wrong for the Windows case, so I have removed it.
1949            (It makes no difference on Unix-like systems.)
1950    
1951    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1952        of recursive calls to match(). This is different to MATCH_LIMIT because
1953        that limits the total number of calls to match(), not all of which increase
1954        the depth of recursion. Limiting the recursion depth limits the amount of
1955        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1956        when PCRE is compiled, and changed at run time. A patch from Google adds
1957        this functionality to the C++ interface.
1958    
1959    18. Changes to the handling of Unicode character properties:
1960    
1961        (a) Updated the table to Unicode 4.1.0.
1962    
1963        (b) Recognize characters that are not in the table as "Cn" (undefined).
1964    
1965        (c) I revised the way the table is implemented to a much improved format
1966            which includes recognition of ranges. It now supports the ranges that
1967            are defined in UnicodeData.txt, and it also amalgamates other
1968            characters into ranges. This has reduced the number of entries in the
1969            table from around 16,000 to around 3,000, thus reducing its size
1970            considerably. I realized I did not need to use a tree structure after
1971            all - a binary chop search is just as efficient. Having reduced the
1972            number of entries, I extended their size from 6 bytes to 8 bytes to
1973            allow for more data.
1974    
1975        (d) Added support for Unicode script names via properties such as \p{Han}.
1976    
1977    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1978        matching that character.
1979    
1980    20. When matching a repeated Unicode property with a minimum greater than zero,
1981        (for example \pL{2,}), PCRE could look past the end of the subject if it
1982        reached it while seeking the minimum number of characters. This could
1983        happen only if some of the characters were more than one byte long, because
1984        there is a check for at least the minimum number of bytes.
1985    
1986    21. Refactored the implementation of \p and \P so as to be more general, to
1987        allow for more different types of property in future. This has changed the
1988        compiled form incompatibly. Anybody with saved compiled patterns that use
1989        \p or \P will have to recompile them.
1990    
1991    22. Added "Any" and "L&" to the supported property types.
1992    
1993    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1994        but give a compile time error if the value is greater than 0xff.
1995    
1996    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1997        accidentally not being installed or uninstalled.
1998    
1999    25. The pcre.h file was built from pcre.h.in, but the only changes that were
2000        made were to insert the current release number. This seemed silly, because
2001        it made things harder for people building PCRE on systems that don't run
2002        "configure". I have turned pcre.h into a distributed file, no longer built
2003        by "configure", with the version identification directly included. There is
2004        no longer a pcre.h.in file.
2005    
2006        However, this change necessitated a change to the pcre-config script as
2007        well. It is built from pcre-config.in, and one of the substitutions was the
2008        release number. I have updated configure.ac so that ./configure now finds
2009        the release number by grepping pcre.h.
2010    
2011    26. Added the ability to run the tests under valgrind.
2012    
2013    
2014    Version 6.4 05-Sep-05
2015    ---------------------
2016    
2017     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
2018        "--" to be printed when multiple files were scanned, even when none of the
2019        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
2020        consider it to be a bug, and have restored the previous behaviour.
2021    
2022     2. A couple of code tidies to get rid of compiler warnings.
2023    
2024     3. The pcretest program used to cheat by referring to symbols in the library
2025        whose names begin with _pcre_. These are internal symbols that are not
2026        really supposed to be visible externally, and in some environments it is
2027        possible to suppress them. The cheating is now confined to including
2028        certain files from the library's source, which is a bit cleaner.
2029    
2030     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
2031        file's purpose clearer.
2032    
2033     5. Reorganized pcre_ucp_findchar().
2034    
2035    
2036    Version 6.3 15-Aug-05
2037    ---------------------
2038    
2039     1. The file libpcre.pc.in did not have general read permission in the tarball.
2040    
2041     2. There were some problems when building without C++ support:
2042    
2043        (a) If C++ support was not built, "make install" and "make test" still
2044            tried to test it.
2045    
2046        (b) There were problems when the value of CXX was explicitly set. Some
2047            changes have been made to try to fix these, and ...
2048    
2049        (c) --disable-cpp can now be used to explicitly disable C++ support.
2050    
2051        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
2052            backslash in a target when C++ was disabled. This confuses some
2053            versions of "make", apparently. Using an intermediate variable solves
2054            this. (Same for CPP_LOBJ.)
2055    
2056     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
2057        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
2058        necessary on certain architectures.
2059    
2060     4. Added a setting of -export-symbols-regex to the link command to remove
2061        those symbols that are exported in the C sense, but actually are local
2062        within the library, and not documented. Their names all begin with
2063        "_pcre_". This is not a perfect job, because (a) we have to except some
2064        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
2065        available (and never for static libraries). I have made a note to try to
2066        find a way round (a) in the future.
2067    
2068    
2069    Version 6.2 01-Aug-05
2070    ---------------------
2071    
2072     1. There was no test for integer overflow of quantifier values. A construction
2073        such as {1111111111111111} would give undefined results. What is worse, if
2074        a minimum quantifier for a parenthesized subpattern overflowed and became
2075        negative, the calculation of the memory size went wrong. This could have
2076        led to memory overwriting.
2077    
2078     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
2079    
2080     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
2081        operating environments where this matters.
2082    
2083     4. Applied Giuseppe Maxia's patch to add additional features for controlling
2084        PCRE options from within the C++ wrapper.
2085    
2086     5. Named capturing subpatterns were not being correctly counted when a pattern
2087        was compiled. This caused two problems: (a) If there were more than 100
2088        such subpatterns, the calculation of the memory needed for the whole
2089        compiled pattern went wrong, leading to an overflow error. (b) Numerical
2090        back references of the form \12, where the number was greater than 9, were
2091        not recognized as back references, even though there were sufficient
2092        previous subpatterns.
2093    
2094     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
2095        versions of gcc, e.g. 2.95.4.
2096    
2097    
2098    Version 6.1 21-Jun-05
2099    ---------------------
2100    
2101     1. There was one reference to the variable "posix" in pcretest.c that was not
2102        surrounded by "#if !defined NOPOSIX".
2103    
2104     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
2105        the cross-check on the old pcre_info() function, for the benefit of the
2106        cut-down version of PCRE that is currently imported into Exim.
2107    
2108     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
2109        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
2110        patterns that start (?i) but I don't think that matters. The use of (?i) is
2111        just an example; this all applies to the other options as well.
2112    
2113     4. Since libtool seems to echo the compile commands it is issuing, the output
2114        from "make" can be reduced a bit by putting "@" in front of each libtool
2115        compile command.
2116    
2117     5. Patch from the folks at Google for configure.in to be a bit more thorough
2118        in checking for a suitable C++ installation before trying to compile the
2119        C++ stuff. This should fix a reported problem when a compiler was present,
2120        but no suitable headers.
2121    
2122     6. The man pages all had just "PCRE" as their title. I have changed them to
2123        be the relevant file name. I have also arranged that these names are
2124        retained in the file doc/pcre.txt, which is a concatenation in text format
2125        of all the man pages except the little individual ones for each function.
2126    
2127     7. The NON-UNIX-USE file had not been updated for the different set of source
2128        files that come with release 6. I also added a few comments about the C++
2129        wrapper.
2130    
2131    
2132    Version 6.0 07-Jun-05
2133    ---------------------
2134    
2135     1. Some minor internal re-organization to help with my DFA experiments.
2136    
2137     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
2138        didn't matter for the library itself when fully configured, but did matter
2139        when compiling without UCP support, or within Exim, where the ucp files are
2140        not imported.
2141    
2142     3. Refactoring of the library code to split up the various functions into
2143        different source modules. The addition of the new DFA matching code (see
2144        below) to a single monolithic source would have made it really too
2145        unwieldy, quite apart from causing all the code to be include in a
2146        statically linked application, when only some functions are used. This is
2147        relevant even without the DFA addition now that patterns can be compiled in
2148        one application and matched in another.
2149    
2150        The downside of splitting up is that there have to be some external
2151        functions and data tables that are used internally in different modules of
2152        the library but which are not part of the API. These have all had their
2153        names changed to start with "_pcre_" so that they are unlikely to clash
2154        with other external names.
2155    
2156     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
2157        a different (DFA) algorithm. Although it is slower than the original
2158        function, it does have some advantages for certain types of matching
2159        problem.
2160    
2161     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
2162        including restarting after a partial match.
2163    
2164     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
2165        defined when compiling for Windows was sent to me. I have put it into the
2166        code, though I have no means of testing or verifying it.
2167    
2168     7. Added the pcre_refcount() auxiliary function.
2169    
2170     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
2171        match before or at the first newline in the subject string. In pcretest,
2172        the /f option on a pattern can be used to set this.
2173    
2174     9. A repeated \w when used in UTF-8 mode with characters greater than 256
2175        would behave wrongly. This has been present in PCRE since release 4.0.
2176    
2177    10. A number of changes to the pcregrep command:
2178    
2179        (a) Refactored how -x works; insert ^(...)$ instead of setting
2180            PCRE_ANCHORED and checking the length, in preparation for adding
2181            something similar for -w.
2182    
2183        (b) Added the -w (match as a word) option.
2184    
2185        (c) Refactored the way lines are read and buffered so as to have more
2186            than one at a time available.
2187    
2188        (d) Implemented a pcregrep test script.
2189    
2190        (e) Added the -M (multiline match) option. This allows patterns to match
2191            over several lines of the subject. The buffering ensures that at least
2192            8K, or the rest of the document (whichever is the shorter) is available
2193            for matching (and similarly the previous 8K for lookbehind assertions).
2194    
2195        (f) Changed the --help output so that it now says
2196    
2197              -w, --word-regex(p)
2198    
2199            instead of two lines, one with "regex" and the other with "regexp"
2200            because that confused at least one person since the short forms are the
2201            same. (This required a bit of code, as the output is generated
2202            automatically from a table. It wasn't just a text change.)
2203    
2204        (g) -- can be used to terminate pcregrep options if the next thing isn't an
2205            option but starts with a hyphen. Could be a pattern or a path name
2206            starting with a hyphen, for instance.
2207    
2208        (h) "-" can be given as a file name to represent stdin.
2209    
2210        (i) When file names are being printed, "(standard input)" is used for
2211            the standard input, for compatibility with GNU grep. Previously
2212            "<stdin>" was used.
2213    
2214        (j) The option --label=xxx can be used to supply a name to be used for
2215            stdin when file names are being printed. There is no short form.
2216    
2217        (k) Re-factored the options decoding logic because we are going to add
2218            two more options that take data. Such options can now be given in four
2219            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
2220    
2221        (l) Added the -A, -B, and -C options for requesting that lines of context
2222            around matches be printed.
2223    
2224        (m) Added the -L option to print the names of files that do not contain
2225            any matching lines, that is, the complement of -l.
2226    
2227        (n) The return code is 2 if any file cannot be opened, but pcregrep does
2228            continue to scan other files.
2229    
2230        (o) The -s option was incorrectly implemented. For compatibility with other
2231            greps, it now suppresses the error message for a non-existent or non-
2232            accessible file (but not the return code). There is a new option called
2233            -q that suppresses the output of matching lines, which was what -s was
2234            previously doing.
2235    
2236        (p) Added --include and --exclude options to specify files for inclusion
2237            and exclusion when recursing.
2238    
2239    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
2240        Hopefully, it now does.
2241    
2242    12. Missing cast in pcre_study().
2243    
2244    13. Added an "uninstall" target to the makefile.
2245    
2246    14. Replaced "extern" in the function prototypes in Makefile.in with
2247        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
2248        world, but is set differently for Windows.
2249    
2250    15. Added a second compiling function called pcre_compile2(). The only
2251        difference is that it has an extra argument, which is a pointer to an
2252        integer error code. When there is a compile-time failure, this is set
2253        non-zero, in addition to the error test pointer being set to point to an
2254        error message. The new argument may be NULL if no error number is required
2255        (but then you may as well call pcre_compile(), which is now just a
2256        wrapper). This facility is provided because some applications need a
2257        numeric error indication, but it has also enabled me to tidy up the way
2258        compile-time errors are handled in the POSIX wrapper.
2259    
2260    16. Added VPATH=.libs to the makefile; this should help when building with one
2261        prefix path and installing with another. (Or so I'm told by someone who
2262        knows more about this stuff than I do.)
2263    
2264    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
2265        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
2266        match everything, including newlines. This is not POSIX-compatible, but
2267        somebody wanted the feature. From pcretest it can be activated by using
2268        both the P and the s flags.
2269    
2270    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
2271    
2272    19. libpcre.pc was being incorrectly installed as executable.
2273    
2274    20. A couple of places in pcretest check for end-of-line by looking for '\n';
2275        it now also looks for '\r' so that it will work unmodified on Windows.
2276    
2277    21. Added Google's contributed C++ wrapper to the distribution.
2278    
2279    22. Added some untidy missing memory free() calls in pcretest, to keep
2280        Electric Fence happy when testing.
2281    
2282    
2283    
2284    Version 5.0 13-Sep-04
2285    ---------------------
2286    
2287     1. Internal change: literal characters are no longer packed up into items
2288        containing multiple characters in a single byte-string. Each character
2289        is now matched using a separate opcode. However, there may be more than one
2290        byte in the character in UTF-8 mode.
2291    
2292     2. The pcre_callout_block structure has two new fields: pattern_position and
2293        next_item_length. These contain the offset in the pattern to the next match
2294        item, and its length, respectively.
2295    
2296     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
2297        insertion of callouts before each pattern item. Added the /C option to
2298        pcretest to make use of this.
2299    
2300     4. On the advice of a Windows user, the lines
2301    
2302          #if defined(_WIN32) || defined(WIN32)
2303          _setmode( _fileno( stdout ), 0x8000 );
2304          #endif  /* defined(_WIN32) || defined(WIN32) */
2305    
2306        have been added to the source of pcretest. This apparently does useful
2307        magic in relation to line terminators.
2308    
2309     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
2310        for the benefit of those environments where the "b" makes a difference.
2311    
2312     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
2313        to know about it. I have put a hack into configure.in that adds in code
2314        to set GCC=yes if CC=icc. This seems to end up at a point in the
2315        generated configure script that is early enough to affect the setting of
2316        compiler options, which is what is needed, but I have no means of testing
2317        whether it really works. (The user who reported this had patched the
2318        generated configure script, which of course I cannot do.)
2319    
2320        LATER: After change 22 below (new libtool files), the configure script
2321        seems to know about icc (and also ecc). Therefore, I have commented out
2322        this hack in configure.in.
2323    
2324     7. Added support for pkg-config (2 patches were sent in).
2325    
2326     8. Negated POSIX character classes that used a combination of internal tables
2327        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
2328        [[:^ascii]]. Typically, they would match almost any characters. The other
2329        POSIX classes were not broken in this way.
2330    
2331     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
2332        to find the match, as PCRE was deluded into thinking that the match had to
2333        start at the start point or following a newline. The same bug applied to
2334        patterns with negative forward assertions or any backward assertions
2335        preceding ".*" at the start, unless the pattern required a fixed first
2336        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
2337    
2338    10. In UTF-8 mode, when moving forwards in the subject after a failed match
2339        starting at the last subject character, bytes beyond the end of the subject
2340        string were read.
2341    
2342    11. Renamed the variable "class" as "classbits" to make life easier for C++
2343        users. (Previously there was a macro definition, but it apparently wasn't
2344        enough.)
2345    
2346    12. Added the new field "tables" to the extra data so that tables can be passed
2347        in at exec time, or the internal tables can be re-selected. This allows
2348        a compiled regex to be saved and re-used at a later time by a different
2349        program that might have everything at different addresses.
2350    
2351    13. Modified the pcre-config script so that, when run on Solaris, it shows a
2352        -R library as well as a -L library.
2353    
2354    14. The debugging options of pcretest (-d on the command line or D on a
2355        pattern) showed incorrect output for anything following an extended class
2356        that contained multibyte characters and which was followed by a quantifier.
2357    
2358    15. Added optional support for general category Unicode character properties
2359        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
2360        support. It adds about 90K to the size of the library. The meanings of the
2361        inbuilt class escapes such as \d and \s have NOT been changed.
2362    
2363    16. Updated pcredemo.c to include calls to free() to release the memory for the
2364        compiled pattern.
2365    
2366    17. The generated file chartables.c was being created in the source directory
2367        instead of in the building directory. This caused the build to fail if the
2368        source directory was different from the building directory, and was
2369        read-only.
2370    
2371    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2372        file. No doubt somebody will tell me if they don't make sense... Also added
2373        Dan Mooney's comments about building on OpenVMS.
2374    
2375    19. Added support for partial matching via the PCRE_PARTIAL option for
2376        pcre_exec() and the \P data escape in pcretest.
2377    
2378    20. Extended pcretest with 3 new pattern features:
2379    
2380        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2381              write the compiled pattern to the file whose name is "rest-of-line".
2382              This is a straight binary dump of the data, with the saved pointer to
2383              the character tables forced to be NULL. The study data, if any, is
2384              written too. After writing, pcretest reads a new pattern.
2385    
2386        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2387              compiled pattern from the given file. There must not be any
2388              occurrences of "<" in the file name (pretty unlikely); if there are,
2389              pcretest will instead treat the initial "<" as a pattern delimiter.
2390              After reading in the pattern, pcretest goes on to read data lines as
2391              usual.
2392    
2393        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2394              and 16-bit fields in a compiled pattern, to simulate a pattern that
2395              was compiled on a host of opposite endianness.
2396    
2397    21. The pcre-exec() function can now cope with patterns that were compiled on
2398        hosts of opposite endianness, with this restriction:
2399    
2400          As for any compiled expression that is saved and used later, the tables
2401          pointer field cannot be preserved; the extra_data field in the arguments
2402          to pcre_exec() should be used to pass in a tables address if a value
2403          other than the default internal tables were used at compile time.
2404    
2405    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2406        now diagnosed as an error. Previously, most of the time, a negative number
2407        would have been treated as zero, but if in addition "ovector" was passed as
2408        NULL, a crash could occur.
2409    
2410    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2411        new versions from the libtool 1.5 distribution (the last one is a copy of
2412        a file called libtool.m4). This seems to have fixed the need to patch
2413        "configure" to support Darwin 1.3 (which I used to do). However, I still
2414        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2415        workstation).
2416    
2417    24. Changed the PCRE licence to be the more standard "BSD" licence.
2418    
2419    
2420    Version 4.5 01-Dec-03
2421    ---------------------
2422    
2423     1. There has been some re-arrangement of the code for the match() function so
2424        that it can be compiled in a version that does not call itself recursively.
2425        Instead, it keeps those local variables that need separate instances for
2426        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2427        needs to "recurse". Keeping track of where control must go is done by means
2428        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2429        hide most of the details from the main code, and operates only if
2430        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2431        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2432        operating.
2433    
2434        To make it easier for callers to provide specially tailored get/free
2435        functions for this usage, two new functions, pcre_stack_malloc, and
2436        pcre_stack_free, are used. They are always called in strict stacking order,
2437        and the size of block requested is always the same.
2438    
2439        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2440        PCRE has been compiled to use the stack or the heap for recursion. The
2441        -C option of pcretest uses this to show which version is compiled.
2442    
2443        A new data escape \S, is added to pcretest; it causes the amounts of store
2444        obtained and freed by both kinds of malloc/free at match time to be added
2445        to the output.
2446    
2447     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2448        what's available on my current Linux desktop machine.
2449    
2450     3. When matching a UTF-8 string, the test for a valid string at the start has
2451        been extended. If start_offset is not zero, PCRE now checks that it points
2452        to a byte that is the start of a UTF-8 character. If not, it returns
2453        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2454        this is necessary because there may be backward assertions in the pattern.
2455        When matching the same subject several times, it may save resources to use
2456        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2457    
2458     4. The code for checking the validity of UTF-8 strings has been tightened so
2459        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2460        containing "overlong sequences".
2461    
2462     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2463        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2464        should have been "&", but it just so happened that all the cases this let
2465        through by mistake were picked up later in the function.
2466    
2467     6. I had used a variable called "isblank" - this is a C99 function, causing
2468        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2469    
2470     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2471        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2472        so the version is shown; (c) stop "make test" echoing "./RunTest".
2473    
2474     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2475    
2476     9. The prototype for memmove() for systems that don't have it was using
2477        size_t, but the inclusion of the header that defines size_t was later. I've
2478        moved the #includes for the C headers earlier to avoid this.
2479    
2480    10. Added some adjustments to the code to make it easier to compiler on certain
2481        special systems:
2482    
2483          (a) Some "const" qualifiers were missing.
2484          (b) Added the macro EXPORT before all exported functions; by default this
2485              is defined to be empty.
2486          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2487              that it reads its output file name as an argument instead of writing
2488              to the standard output and assuming this can be redirected.
2489    
2490    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2491        class containing characters with values greater than 255, PCRE compilation
2492        went into a loop.
2493    
2494    12. A recursive reference to a subpattern that was within another subpattern
2495        that had a minimum quantifier of zero caused PCRE to crash. For example,
2496        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2497        recursion. If the recursively-called subpattern itself had a zero repeat,
2498        that was OK.
2499    
2500    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2501        buffer into which it was copied (for escape processing) was still set at
2502        1024, so long lines caused crashes.
2503    
2504    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2505        "internal error: code overflow...". This applied to any character class
2506        that was followed by a possessive quantifier.
2507    
2508    15. Modified the Makefile to add libpcre.la as a prerequisite for
2509        libpcreposix.la because I was told this is needed for a parallel build to
2510        work.
2511    
2512    16. If a pattern that contained .* following optional items at the start was
2513        studied, the wrong optimizing data was generated, leading to matching
2514        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2515        matching string must start with a or b or c. The correct conclusion for
2516        this pattern is that a match can start with any character.
2517    
2518    
2519    Version 4.4 13-Aug-03
2520    ---------------------
2521    
2522     1. In UTF-8 mode, a character class containing characters with values between
2523        127 and 255 was not handled correctly if the compiled pattern was studied.
2524        In fixing this, I have also improved the studying algorithm for such
2525        classes (slightly).
2526    
2527     2. Three internal functions had redundant arguments passed to them. Removal
2528        might give a very teeny performance improvement.
2529    
2530     3. Documentation bug: the value of the capture_top field in a callout is *one
2531        more than* the number of the hightest numbered captured substring.
2532    
2533     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2534        in incorrectly linking with a previously installed version. They now link
2535        explicitly with libpcre.la.
2536    
2537     5. configure.in no longer needs to recognize Cygwin specially.
2538    
2539     6. A problem in pcre.in for Windows platforms is fixed.
2540    
2541     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2542        pcretest, it used to include the size of the study block as part of its
2543        output. Unfortunately, the structure contains a field that has a different
2544        size on different hardware architectures. This meant that the tests that
2545        showed this size failed. As the block is currently always of a fixed size,
2546        this information isn't actually particularly useful in pcretest output, so
2547        I have just removed it.
2548    
2549     8. Three pre-processor statements accidentally did not start in column 1.
2550        Sadly, there are *still* compilers around that complain, even though
2551        standard C has not required this for well over a decade. Sigh.
2552    
2553     9. In pcretest, the code for checking callouts passed small integers in the
2554        callout_data field, which is a void * field. However, some picky compilers
2555        complained about the casts involved for this on 64-bit systems. Now
2556        pcretest passes the address of the small integer instead, which should get
2557        rid of the warnings.
2558    
2559    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2560        both compile and run time, and gives an error if an invalid UTF-8 sequence
2561        is found. There is a option for disabling this check in cases where the
2562        string is known to be correct and/or the maximum performance is wanted.
2563    
2564    11. In response to a bug report, I changed one line in Makefile.in from
2565    
2566            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2567        to
2568            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2569    
2570        to look similar to other lines, but I have no way of telling whether this
2571        is the right thing to do, as I do not use Windows. No doubt I'll get told
2572        if it's wrong...
2573    
2574    
2575    Version 4.3 21-May-03
2576    ---------------------
2577    
2578    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2579       Makefile.
2580    
2581    2. Some refactoring to improve the quality of the code:
2582    
2583       (i)   The utf8_table... variables are now declared "const".
2584    
2585       (ii)  The code for \cx, which used the "case flipping" table to upper case
2586             lower case letters, now just substracts 32. This is ASCII-specific,
2587             but the whole concept of \cx is ASCII-specific, so it seems
2588             reasonable.
2589    
2590       (iii) PCRE was using its character types table to recognize decimal and
2591             hexadecimal digits in the pattern. This is silly, because it handles
2592             only 0-9, a-f, and A-F, but the character types table is locale-
2593             specific, which means strange things might happen. A private
2594             table is now used for this - though it costs 256 bytes, a table is
2595             much faster than multiple explicit tests. Of course, the standard
2596             character types table is still used for matching digits in subject
2597             strings against \d.
2598    
2599       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2600             ending in _t are). So I've renamed it as ESC_tee.
2601    
2602    3. The first argument for regexec() in the POSIX wrapper should have been
2603       defined as "const".
2604    
2605    4. Changed pcretest to use malloc() for its buffers so that they can be
2606       Electric Fenced for debugging.
2607    
2608    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2609       to read one or more bytes before the start of the subject string. Often this
2610       had no effect on PCRE's behaviour, but in some circumstances it could
2611       provoke a segmentation fault.
2612    
2613    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2614       to try to read one or more bytes before the start of the subject string.
2615    
2616    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2617       UTF-8 support could misbehave in various ways if the subject string
2618       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2619       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2620       back over UTF-8 characters.)
2621    
2622    
2623    Version 4.2 14-Apr-03
2624    ---------------------
2625    
2626    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2627    
2628    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2629         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2630         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2631         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2632         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2633           and BUILD_EXEEXT
2634         Note: automatic setting of the BUILD variables is not yet working
2635         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2636           compile-time but not at link-time
2637         [LINK]: use for linking executables only
2638         make different versions for Windows and non-Windows
2639         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2640           libraries
2641         [LINK_FOR_BUILD]: new variable
2642         [OBJEXT]: use throughout
2643         [EXEEXT]: use throughout
2644         <winshared>: new target
2645         <wininstall>: new target
2646         <dftables.o>: use native compiler
2647         <dftables>: use native linker
2648         <install>: handle Windows platform correctly
2649         <clean>: ditto
2650         <check>: ditto
2651         copy DLL to top builddir before testing
2652    
2653       As part of these changes, -no-undefined was removed again. This was reported
2654       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2655       in any case.
2656    
2657    3. Some tidies to get rid of compiler warnings:
2658    
2659       . In the match_data structure, match_limit was an unsigned long int, whereas
2660         match_call_count was an int. I've made them both unsigned long ints.
2661    
2662       . In pcretest the fact that a const uschar * doesn't automatically cast to
2663         a void * provoked a warning.
2664    
2665       . Turning on some more compiler warnings threw up some "shadow" variables
2666         and a few more missing casts.
2667    
2668    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2669       option, a class that contained a single character with a value between 128
2670       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2671    
2672    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2673       option, a class that contained several characters, but with at least one
2674       whose value was between 128 and 255 caused PCRE to crash.
2675    
2676    
2677    Version 4.1 12-Mar-03
2678    ---------------------
2679    
2680    1. Compiling with gcc -pedantic found a couple of places where casts were
2681    needed, and a string in dftables.c that was longer than standard compilers are
2682    required to support.
2683    
2684    2. Compiling with Sun's compiler found a few more places where the code could
2685    be tidied up in order to avoid warnings.
2686    
2687    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2688    first of these names is deprecated in the latest Autoconf in favour of the name
2689    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2690    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2691    analogy I have changed it to CFLAGS_FOR_BUILD.
2692    
2693    4. Added -no-undefined to the linking command in the Makefile, because this is
2694    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2695    linking step for the pcreposix library.
2696    
2697    5. PCRE was failing to diagnose the case of two named groups with the same
2698    name.
2699    
2700    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2701    literal character that is needed in the subject for a match, and scans along to
2702    ensure that it is present before embarking on the full matching process. This
2703    saves time in cases of nested unlimited repeats that are never going to match.
2704    Problem: the scan can take a lot of time if the subject is very long (e.g.
2705    megabytes), thus penalizing straightforward matches. It is now done only if the
2706    amount of subject to be scanned is less than 1000 bytes.
2707    
2708    7. A lesser problem with the same optimization is that it was recording the
2709    first character of an anchored pattern as "needed", thus provoking a search
2710    right along the subject, even when the first match of the pattern was going to
2711    fail. The "needed" character is now not set for anchored patterns, unless it
2712    follows something in the pattern that is of non-fixed length. Thus, it still
2713    fulfils its original purpose of finding quick non-matches in cases of nested
2714    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2715    
2716    
2717    Version 4.0 17-Feb-03
2718    ---------------------
2719    
2720    1. If a comment in an extended regex that started immediately after a meta-item
2721    extended to the end of string, PCRE compiled incorrect data. This could lead to
2722    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2723    
2724    2. Moved to autoconf 2.53 and libtool 1.4.2.
2725    
2726    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2727    the special perltest8 script is no longer needed - all the tests can be run
2728    from a single perltest script.
2729    
2730    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2731    by \s. It has now been removed in PCRE. This means it isn't recognized as
2732    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2733    class [:space:] *does* include VT, thereby creating a mess.
2734    
2735    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2736    space and tab.
2737    
2738    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2739    its new features into the main test script, reducing the number of scripts.
2740    
2741    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2742    were backward compatible, and made the (?i) apply to the whole pattern, as if
2743    /i were given. Now it behaves more logically, and applies the option setting
2744    only to what follows. PCRE has been changed to follow suit. However, if it
2745    finds options settings right at the start of the pattern, it extracts them into
2746    the global options, as before. Thus, they show up in the info data.
2747    
2748    8. Added support for the \Q...\E escape sequence. Characters in between are
2749    treated as literals. This is slightly different from Perl in that $ and @ are
2750    also handled as literals inside the quotes. In Perl, they will cause variable
2751    interpolation. Note the following examples:
2752    
2753        Pattern            PCRE matches      Perl matches
2754    
2755        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2756        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2757        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2758    
2759    For compatibility with Perl, \Q...\E sequences are recognized inside character
2760    classes as well as outside them.
2761    
2762    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2763    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2764    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2765    signed/unsigned warnings.
2766    
2767    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2768    option for pcretest, so I've replaced it by a simple function that does just
2769    that job.
2770    
2771    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2772    "pcregrep -".
2773    
2774    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2775    Java package. This provides some syntactic sugar for simple cases of what my
2776    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2777    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2778    item, you can use this simplified notation. Note that only makes sense with
2779    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2780    greediness, whatever the setting of the PCRE_UNGREEDY option.
2781    
2782    13. A change of greediness default within a pattern was not taking effect at
2783    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2784    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2785    was abstracted outside.
2786    
2787    14. PCRE now supports the \G assertion. It is true when the current matching
2788    position is at the start point of the match. This differs from \A when the
2789    starting offset is non-zero. Used with the /g option of pcretest (or similar
2790    code), it works in the same way as it does for Perl's /g option. If all
2791    alternatives of a regex begin with \G, the expression is anchored to the start
2792    match position, and the "anchored" flag is set in the compiled expression.
2793    
2794    15. Some bugs concerning the handling of certain option changes within patterns
2795    have been fixed. These applied to options other than (?ims). For example,
2796    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2797    been the other way round. Some of this was related to change 7 above.
2798    
2799    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2800    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2801    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2802    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2803    
2804    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2805    mode. Unlike ".", it always matches newline, whatever the setting of
2806    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2807    assertions. Perl allows it, but it doesn't (in general) work because it can't
2808    calculate the length of the lookbehind. At least, that's the case for Perl
2809    5.8.0 - I've been told they are going to document that it doesn't work in
2810    future.
2811    
2812    18. Added an error diagnosis for escapes that PCRE does not support: these are
2813    \L, \l, \N, \P, \p, \U, \u, and \X.
2814    
2815    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2816    reading past the end of the pattern in cases such as /[abcd/.
2817    
2818    20. PCRE was getting more memory than necessary for patterns with classes that
2819    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2820    
2821    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2822    compiling PCRE for use with Virtual Pascal.
2823    
2824    22. Small fix to the Makefile to make it work properly if the build is done
2825    outside the source tree.
2826    
2827    23. Added a new extension: a condition to go with recursion. If a conditional
2828    subpattern starts with (?(R) the "true" branch is used if recursion has
2829    happened, whereas the "false" branch is used only at the top level.
2830    
2831    24. When there was a very long string of literal characters (over 255 bytes
2832    without UTF support, over 250 bytes with UTF support), the computation of how
2833    much memory was required could be incorrect, leading to segfaults or other
2834    strange effects.
2835    
2836    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2837    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2838    there was a subsequent back reference to those brackets. This meant that, for
2839    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2840    possible to check for precisely this case. All we can do is abandon the
2841    optimization if .* occurs inside capturing brackets when there are any back
2842    references whatsoever. (See below for a better fix that came later.)
2843    
2844    26. The handling of the optimization for finding the first character of a
2845    non-anchored pattern, and for finding a character that is required later in the
2846    match were failing in some cases. This didn't break the matching; it just
2847    failed to optimize when it could. The way this is done has been re-implemented.
2848    
2849    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2850    
2851    28. Added a new feature that provides some of the functionality that Perl
2852    provides with (?{...}). The facility is termed a "callout". The way it is done
2853    in PCRE is for the caller to provide an optional function, by setting
2854    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2855    global variable. By default it is unset, which disables all calling out. To get
2856    the function called, the regex must include (?C) at appropriate points. This
2857    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2858    This provides a means of identifying different callout points. When PCRE
2859    reaches such a point in the regex, if pcre_callout has been set, the external
2860    function is called. It is provided with data in a structure called
2861    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2862    matching continues; if it returns a non-zero value, the match at the current
2863    point fails. However, backtracking will occur if possible. [This was changed
2864    later and other features added - see item 49 below.]
2865    
2866    29. pcretest is upgraded to test the callout functionality. It provides a
2867    callout function that displays information. By default, it shows the start of
2868    the match and the current position in the text. There are some new data escapes
2869    to vary what happens:
2870    
2871        \C+         in addition, show current contents of captured substrings
2872        \C-         do not supply a callout function
2873        \C!n        return 1 when callout number n is reached
2874        \C!n!m      return 1 when callout number n is reached for the mth time
2875    
2876    30. If pcregrep was called with the -l option and just a single file name, it
2877    output "<stdin>" if a match was found, instead of the file name.
2878    
2879    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2880    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2881    pcre_exec(). This saves a malloc/free per call. The default value of
2882    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2883    when configuring.
2884    
2885    32. The default maximum size of a compiled pattern is 64K. There have been a
2886    few cases of people hitting this limit. The code now uses macros to handle the
2887    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2888    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2889    configuring. Tests 2 and 5 work only with 2-byte links because they output
2890    debugging information about compiled patterns.
2891    
2892    33. Internal code re-arrangements:
2893    
2894    (a) Moved the debugging function for printing out a compiled regex into
2895        its own source file (printint.c) and used #include to pull it into
2896        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2897        separate copies.
2898    
2899    (b) Defined the list of op-code names for debugging as a macro in
2900        internal.h so that it is next to the definition of the opcodes.
2901    
2902    (c) Defined a table of op-code lengths for simpler skipping along compiled
2903        code. This is again a macro in internal.h so that it is next to the
2904        definition of the opcodes.
2905    
2906    34. Added support for recursive calls to individual subpatterns, along the
2907    lines of Robin Houston's patch (but implemented somewhat differently).
2908    
2909    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2910    allow it to read and process whole directories in Win32. This code was
2911    contributed by Lionel Fourquaux; it has not been tested by me.
2912    
2913    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2914    used to name a group. Names consist of alphanumerics and underscores, and must
2915    be unique. Back references use the syntax (?P=name) and recursive calls use
2916    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2917    numbers. The function pcre_fullinfo() can be used after compilation to extract
2918    a name/number map. There are three relevant calls:
2919    
2920      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2921      PCRE_INFO_NAMECOUNT            yields the number of entries
2922      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2923    
2924    The map is a vector of fixed-size entries. The size of each entry depends on
2925    the length of the longest name used. The first two bytes of each entry are the
2926    group number, most significant byte first. There follows the corresponding
2927    name, zero terminated. The names are in alphabetical order.
2928    
2929    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2930    case instead of 255. Making it the same both with and without UTF-8 support
2931    means that the same test output works with both.
2932    
2933    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2934    calling malloc() with a zero argument.
2935    
2936    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2937    optimization. I've improved things by keeping a bitmap of backreferences with
2938    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2939    fact referenced, the optimization can be applied. It is unlikely that a
2940    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2941    the match to follow \n) will appear inside brackets with a number greater than
2942    31, but if it does, any back reference > 31 suppresses the optimization.
2943    
2944    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2945    of disabling numbered capturing parentheses. Any opening parenthesis that is
2946    not followed by ? behaves as if it were followed by ?: but named parentheses
2947    can still be used for capturing (and they will acquire numbers in the usual
2948    way).
2949    
2950    41. Redesigned the return codes from the match() function into yes/no/error so
2951    that errors can be passed back from deep inside the nested calls. A malloc
2952    failure while inside a recursive subpattern call now causes the
2953    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2954    
2955    42. It is now possible to set a limit on the number of times the match()
2956    function is called in a call to pcre_exec(). This facility makes it possible to
2957    limit the amount of recursion and backtracking, though not in a directly
2958    obvious way, because the match() function is used in a number of different
2959    circumstances. The count starts from zero for each position in the subject
2960    string (for non-anchored patterns). The default limit is, for compatibility, a
2961    large number, namely 10 000 000. You can change this in two ways:
2962    
2963    (a) When configuring PCRE before making, you can use --with-match-limit=n
2964        to set a default value for the compiled library.
2965    
2966    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2967        a different value is set. See 45 below.
2968    
2969    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2970    
2971    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2972    of things that can be changed at compile time. The first argument specifies
2973    what is wanted and the second points to where the information is to be placed.
2974    The current list of available information is:
2975    
2976      PCRE_CONFIG_UTF8
2977    
2978    The output is an integer that is set to one if UTF-8 support is available;
2979    otherwise it is set to zero.
2980    
2981      PCRE_CONFIG_NEWLINE
2982    
2983    The output is an integer that it set to the value of the code that is used for
2984    newline. It is either LF (10) or CR (13).
2985    
2986      PCRE_CONFIG_LINK_SIZE
2987    
2988    The output is an integer that contains the number of bytes used for internal
2989    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2990    
2991      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2992    
2993    The output is an integer that contains the threshold above which the POSIX
2994    interface uses malloc() for output vectors. See item 31 above.
2995    
2996      PCRE_CONFIG_MATCH_LIMIT
2997    
2998    The output is an unsigned integer that contains the default limit of the number
2999    of match() calls in a pcre_exec() execution. See 42 above.
3000    
3001    44. pcretest has been upgraded by the addition of the -C option. This causes it
3002    to extract all the available output from the new pcre_config() function, and to
3003    output it. The program then exits immediately.
3004    
3005    45. A need has arisen to pass over additional data with calls to pcre_exec() in
3006    order to support additional features. One way would have been to define
3007    pcre_exec2() (for example) with extra arguments, but this would not have been
3008    extensible, and would also have required all calls to the original function to
3009    be mapped to the new one. Instead, I have chosen to extend the mechanism that
3010    is used for passing in "extra" data from pcre_study().
3011    
3012    The pcre_extra structure is now exposed and defined in pcre.h. It currently
3013    contains the following fields:
3014    
3015      flags         a bitmap indicating which of the following fields are set
3016      study_data    opaque data from pcre_study()
3017      match_limit   a way of specifying a limit on match() calls for a specific
3018                      call to pcre_exec()
3019      callout_data  data for callouts (see 49 below)
3020    
3021    The flag bits are also defined in pcre.h, and are
3022    
3023      PCRE_EXTRA_STUDY_DATA
3024      PCRE_EXTRA_MATCH_LIMIT
3025      PCRE_EXTRA_CALLOUT_DATA
3026    
3027    The pcre_study() function now returns one of these new pcre_extra blocks, with
3028    the actual study data pointed to by the study_data field, and the
3029    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
3030    before. That is, this change is entirely upwards-compatible and requires no
3031    change to existing code.
3032    
3033    If you want to pass in additional data to pcre_exec(), you can either place it
3034    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
3035    block.
3036    
3037    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
3038    data string contains the escape sequence \M, pcretest calls pcre_exec() several
3039    times with different match limits, until it finds the minimum value needed for
3040    pcre_exec() to complete. The value is then output. This can be instructive; for
3041    most simple matches the number is quite small, but for pathological cases it
3042    gets very large very quickly.
3043    
3044    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
3045    returns the size of the data block pointed to by the study_data field in a
3046    pcre_extra block, that is, the value that was passed as the argument to
3047    pcre_malloc() when PCRE was getting memory in which to place the information
3048    created by pcre_study(). The fourth argument should point to a size_t variable.
3049    pcretest has been extended so that this information is shown after a successful
3050    pcre_study() call when information about the compiled regex is being displayed.
3051    
3052    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
3053    because what follows is always an absolute path. (Later: it turns out that this
3054    is more than cosmetic for MinGW, because it doesn't like empty path
3055    components.)
3056    
3057    49. Some changes have been made to the callout feature (see 28 above):
3058    
3059    (i)  A callout function now has three choices for what it returns:
3060    
3061           0  =>  success, carry on matching
3062         > 0  =>  failure at this point, but backtrack if possible
3063         < 0  =>  serious error, return this value from pcre_exec()
3064    
3065         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
3066         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
3067         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
3068         use by callout functions. It will never be used by PCRE itself.
3069    
3070    (ii) The pcre_extra structure (see 45 above) has a void * field called
3071         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
3072         pcre_callout_block structure has a field of the same name. The contents of
3073         the field passed in the pcre_extra structure are passed to the callout
3074         function in the corresponding field in the callout block. This makes it
3075         easier to use the same callout-containing regex from multiple threads. For
3076         testing, the pcretest program has a new data escape
3077    
3078           \C*n        pass the number n (may be negative) as callout_data
3079    
3080         If the callout function in pcretest receives a non-zero value as
3081         callout_data, it returns that value.
3082    
3083    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
3084    there were some redundant $(CFLAGS) in commands that are now specified as
3085    $(LINK), which already includes $(CFLAGS).
3086    
3087    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
3088    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
3089    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
3090    one-byte characters throughout. Note that case-insensitive matching applies
3091    only to characters whose values are less than 256. PCRE doesn't support the
3092    notion of cases for higher-valued characters.
3093    
3094    (i)   A character class whose characters are all within 0-255 is handled as
3095          a bit map, and the map is inverted for negative classes. Previously, a
3096          character > 255 always failed to match such a class; however it should
3097          match if the class was a negative one (e.g. [^ab]). This has been fixed.
3098    
3099    (ii)  A negated character class with a single character < 255 is coded as
3100          "not this character" (OP_NOT). This wasn't working properly when the test
3101          character was multibyte, either singly or repeated.
3102    
3103    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
3104          mode, for example: \x{100}{2,3}.
3105    
3106    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
3107          singly or repeated) now correctly test multibyte characters. However,
3108          PCRE doesn't recognize any characters with values greater than 255 as
3109          digits, spaces, or word characters. Such characters always match \D, \S,
3110          and \W, and never match \d, \s, or \w.
3111    
3112    (v)   Classes may now contain characters and character ranges with values
3113          greater than 255. For example: [ab\x{100}-\x{400}].
3114    
3115    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
3116          PCRE in UTF-8 mode.
3117    
3118    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
3119    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
3120    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
3121    value.)
3122    
3123    53. The single man page has become too large. I have therefore split it up into
3124    a number of separate man pages. These also give rise to individual HTML pages;
3125    these are now put in a separate directory, and there is an index.html page that
3126    lists them all. Some hyperlinking between the pages has been installed.
3127    
3128    54. Added convenience functions for handling named capturing parentheses.
3129    
3130    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
3131    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
3132    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
3133    are faulted.
3134    
3135    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
3136    calling configure. These values are used when compiling the dftables.c program
3137    which is run to generate the source of the default character tables. They
3138    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
3139    you will need to set these values.
3140    
3141    57. Updated the building process for Windows DLL, as provided by Fred Cox.
3142    
3143    
3144    Version 3.9 02-Jan-02
3145    ---------------------
3146    
3147    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
3148    
3149    2. If --disable-static was given, the building process failed when trying to
3150    build pcretest and pcregrep. (For some reason it was using libtool to compile
3151    them, which is not right, as they aren't part of the library.)
3152    
3153    
3154    Version 3.8 18-Dec-01
3155    ---------------------
3156    
3157    1. The experimental UTF-8 code was completely screwed up. It was packing the
3158    bytes in the wrong order. How dumb can you get?
3159    
3160    
3161    Version 3.7 29-Oct-01
3162    ---------------------
3163    
3164    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
3165    This caused pcretest, when used on the test data, to segfault. Unfortunately,
3166    this didn't happen under Solaris 8, where I normally test things.
3167    
3168    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
3169    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
3170    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
3171    this fix an hour or so after the initial 3.7 release.)
3172    
3173    
3174    Version 3.6 23-Oct-01
3175    ---------------------
3176    
3177    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
3178    offsets passed as NULL with zero offset count.
3179    
3180    2. The config.guess and config.sub files had not been updated when I moved to
3181    the latest autoconf.
3182    
3183    
3184    Version 3.5 15-Aug-01
3185    ---------------------
3186    
3187    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
3188    had been forgotten.
3189    
3190    2. By using declared but undefined structures, we can avoid using "void"
3191    definitions in pcre.h while keeping the internal definitions of the structures
3192    private.
3193    
3194    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
3195    user point of view, this means that both static and shared libraries are built
3196    by default, but this can be individually controlled. More of the work of
3197    handling this static/shared cases is now inside libtool instead of PCRE's make
3198    file.
3199    
3200    4. The pcretest utility is now installed along with pcregrep because it is
3201    useful for users (to test regexs) and by doing this, it automatically gets
3202    relinked by libtool. The documentation has been turned into a man page, so
3203    there are now .1, .txt, and .html versions in /doc.
3204    
3205    5. Upgrades to pcregrep:
3206       (i)   Added long-form option names like gnu grep.
3207       (ii)  Added --help to list all options with an explanatory phrase.
3208       (iii) Added -r, --recursive to recurse into sub-directories.
3209       (iv)  Added -f, --file to read patterns from a file.
3210    
3211    6. pcre_exec() was referring to its "code" argument before testing that
3212    argument for NULL (and giving an error if it was NULL).
3213    
3214    7. Upgraded Makefile.in to allow for compiling in a different directory from
3215    the source directory.
3216    
3217    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
3218    options bits, the pointer it was passed was to an int instead of to an unsigned
3219    long int. This mattered only on 64-bit systems.
3220    
3221    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
3222    generated) instead of pcre.in, which it its source. Also made the same change
3223    in several of the .c files.
3224    
3225    10. A new release of gcc defines printf() as a macro, which broke pcretest
3226    because it had an ifdef in the middle of a string argument for printf(). Fixed
3227    by using separate calls to printf().
3228    
3229    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
3230    script, to force use of CR or LF instead of \n in the source. On non-Unix
3231    systems, the value can be set in config.h.
3232    
3233    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
3234    absolute limit. Changed the text of the error message to make this clear, and
3235    likewise updated the man page.
3236    
3237    13. The limit of 99 on the number of capturing subpatterns has been removed.
3238    The new limit is 65535, which I hope will not be a "real" limit.
3239    
3240    
3241    Version 3.4 22-Aug-00
3242    ---------------------
3243    
3244    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
3245    
3246    2. Diagnose condition (?(0) as an error instead of crashing on matching.
3247    
3248    
3249    Version 3.3 01-Aug-00
3250    ---------------------
3251    
3252    1. If an octal character was given, but the value was greater than \377, it
3253    was not getting masked to the least significant bits, as documented. This could
3254    lead to crashes in some systems.
3255    
3256    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
3257    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
3258    
3259    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
3260    These just pass their arguments on to (pcre_free)(), but they are provided
3261    because some uses of PCRE bind it to non-C systems that can call its functions,
3262    but cannot call free() or pcre_free() directly.
3263    
3264    4. Add "make test" as a synonym for "make check". Corrected some comments in
3265    the Makefile.
3266    
3267    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
3268    Makefile.
3269    
3270    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
3271    command called pgrep for grepping around the active processes.
3272    
3273    7. Added the beginnings of support for UTF-8 character strings.
3274    
3275    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
3276    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
3277    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
3278    out for the ar command.)
3279    
3280    
3281    Version 3.2 12-May-00
3282    ---------------------
3283    
3284    This is purely a bug fixing release.
3285    
3286    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
3287    of ZA. This was just one example of several cases that could provoke this bug,
3288    which was introduced by change 9 of version 2.00. The code for breaking
3289    infinite loops after an iteration that matches an empty string was't working
3290    correctly.
3291    
3292    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
3293    when matched against abbab (for example). After matching an empty string, it
3294    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
3295    caused it to match further down the string than it should.
3296    
3297    3. The code contained an inclusion of sys/types.h. It isn't clear why this
3298    was there because it doesn't seem to be needed, and it causes trouble on some
3299    systems, as it is not a Standard C header. It has been removed.
3300    
3301    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
3302    were reported on the Macintosh. The changes were from
3303    
3304      while ((c = *(++ptr)) != 0 && c != '\n');
3305    to
3306      while ((c = *(++ptr)) != 0 && c != '\n') ;
3307    
3308    Totally extraordinary, but if that's what it takes...
3309    
3310    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
3311    available. Added HAVE_BCOPY and an autoconf test for it; if neither
3312    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
3313    assumes the way PCRE uses memmove() (always moving upwards).
3314    
3315    6. PCRE is being used in one environment where strchr() is not available. There
3316    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
3317    faster code anyway.
3318    
3319    
3320    Version 3.1 09-Feb-00
3321    ---------------------
3322    
3323    The only change in this release is the fixing of some bugs in Makefile.in for
3324    the "install" target:
3325    
3326    (1) It was failing to install pcreposix.h.
3327    
3328    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
3329    
3330    
3331    Version 3.0 01-Feb-00
3332    ---------------------
3333    
3334    1. Add support for the /+ modifier to perltest (to output $` like it does in
3335    pcretest).
3336    
3337    2. Add support for the /g modifier to perltest.
3338    
3339    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
3340    matches null strings.
3341    
3342    4. Fix perltest so that it doesn't do unwanted things when fed an empty
3343    pattern. Perl treats empty patterns specially - it reuses the most recent
3344    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
3345    effect.
3346    
3347    5. The POSIX interface was broken in that it was just handing over the POSIX
3348    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
3349    required a bigger vector, with some working space on the end. This means that
3350    the POSIX wrapper now has to get and free some memory, and copy the results.
3351    
3352    6. Added some simple autoconf support, placing the test data and the
3353    documentation in separate directories, re-organizing some of the
3354    information files, and making it build pcre-config (a GNU standard). Also added
3355    libtool support for building PCRE as a shared library, which is now the
3356    default.
3357    
3358    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
3359    09 are not valid octal constants. Single digits will be used for minor values
3360    less than 10.
3361    
3362    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3363    existing programs that set these in the POSIX interface can use PCRE without
3364    modification.
3365    
3366    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3367    return all that pcre_info() returns, plus additional data. The pcre_info()
3368    function is retained for compatibility, but is considered to be obsolete.
3369    
3370    10. Added experimental recursion feature (?R) to handle one common case that
3371    Perl 5.6 will be able to do with (?p{...}).
3372    
3373    11. Added support for POSIX character classes like [:alpha:], which Perl is
3374    adopting.
3375    
3376    
3377    Version 2.08 31-Aug-99
3378    ----------------------
3379    
3380    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3381    trying to match at the startoffset position, but instead was moving forward to
3382    the next newline as if a previous match had failed.
3383    
3384    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3385    and could get into a loop if a null string was matched other than at the start
3386    of the subject.
3387    
3388    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3389    be distinguished at compile time, and for completeness also added PCRE_DATE.
3390    
3391    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3392    in GnuWin32 environments.
3393    
3394    
3395    Version 2.07 29-Jul-99
3396    ----------------------
3397    
3398    1. The documentation is now supplied in plain text form and HTML as well as in
3399    the form of man page sources.
3400    
3401    2. C++ compilers don't like assigning (void *) values to other pointer types.
3402    In particular this affects malloc(). Although there is no problem in Standard
3403    C, I've put in casts to keep C++ compilers happy.
3404    
3405    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3406    should be (const char *).
3407    
3408    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3409    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3410    However, I haven't made this a standard facility. The documentation doesn't
3411    mention it, and the Makefile doesn't support it.
3412    
3413    5. The Makefile now contains an "install" target, with editable destinations at
3414    the top of the file. The pcretest program is not installed.
3415    
3416    6. pgrep -V now gives the PCRE version number and date.
3417    
3418    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3419    causing the entire string to be ignored, instead of just the last character.
3420    
3421    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3422    non-matching string, it can take a very, very long time, even for strings of
3423    quite modest length, because of the nested recursion. PCRE now does better in
3424    some of these cases. It does this by remembering the last required literal
3425    character in the pattern, and pre-searching the subject to ensure it is present
3426    before running the real match. In other words, it applies a heuristic to detect
3427    some types of certain failure quickly, and in the above example, if presented
3428    with a string that has no trailing " it gives "no match" very quickly.
3429    
3430    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3431    other alternatives are tried instead.
3432    
3433    
3434    Version 2.06 09-Jun-99
3435    ----------------------
3436    
3437    1. Change pcretest's output for amount of store used to show just the code
3438    space, because the remainder (the data block) varies in size between 32-bit and
3439    64-bit systems.
3440    
3441    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3442    start matching at. This allows lookbehinds to work when searching for multiple
3443    occurrences in a string.
3444    
3445    3. Added additional options to pcretest for testing multiple occurrences:
3446    
3447       /+   outputs the rest of the string that follows a match
3448       /g   loops for multiple occurrences, using the new startoffset argument
3449       /G   loops for multiple occurrences by passing an incremented pointer
3450    
3451    4. PCRE wasn't doing the "first character" optimization for patterns starting
3452    with \b or \B, though it was doing it for other lookbehind assertions. That is,
3453    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3454    the letter 'x'. On long subject strings, this gives a significant speed-up.
3455    
3456    
3457    Version 2.05 21-Apr-99
3458    ----------------------
3459    
3460    1. Changed the type of magic_number from int to long int so that it works
3461    properly on 16-bit systems.
3462    
3463    2. Fixed a bug which caused patterns starting with .* not to work correctly
3464    when the subject string contained newline characters. PCRE was assuming
3465    anchoring for such patterns in all cases, which is not correct because .* will
3466    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3467    DOTALL is set at top level; otherwise it knows that patterns starting with .*
3468    must be retried after every newline in the subject.
3469    
3470    
3471    Version 2.04 18-Feb-99
3472    ----------------------
3473    
3474    1. For parenthesized subpatterns with repeats whose minimum was zero, the
3475    computation of the store needed to hold the pattern was incorrect (too large).
3476    If such patterns were nested a few deep, this could multiply and become a real
3477    problem.
3478    
3479    2. Added /M option to pcretest to show the memory requirement of a specific
3480    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3481    
3482    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3483    compiled in such a way that the backtracking after subsequent failure was
3484    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3485    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3486    
3487    
3488    Version 2.03 02-Feb-99
3489    ----------------------
3490    
3491    1. Fixed typo and small mistake in man page.
3492    
3493    2. Added 4th condition (GPL supersedes if conflict) and created separate
3494    LICENCE file containing the conditions.
3495    
3496    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3497    Perl, that is the internal \ allows the delimiter to be included in the
3498    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3499    the final delimiter, add \ to the end of the pattern (to test the error).
3500    
3501    4. Added the convenience functions for extracting substrings after a successful
3502    match. Updated pcretest to make it able to test these functions.
3503    
3504    
3505    Version 2.02 14-Jan-99
3506    ----------------------
3507    
3508    1. Initialized the working variables associated with each extraction so that
3509    their saving and restoring doesn't refer to uninitialized store.
3510    
3511    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3512    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3513    fix the problem.
3514    
3515    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3516    calls, and wasn't printing the correct value for compiling calls. Increased the
3517    default value of LOOPREPEAT, and the number of significant figures in the
3518    times.
3519    
3520    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3521    
3522    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3523    a building problem on Windows NT with a FAT file system.
3524    
3525    
3526    Version 2.01 21-Oct-98
3527    ----------------------
3528    
3529    1. Changed the API for pcre_compile() to allow for the provision of a pointer
3530    to character tables built by pcre_maketables() in the current locale. If NULL
3531    is passed, the default tables are used.
3532    
3533    
3534    Version 2.00 24-Sep-98
3535    ----------------------
3536    
3537    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3538    it any more.
3539    
3540    2. Allow quantification of (?>) groups, and make it work correctly.
3541    
3542    3. The first character computation wasn't working for (?>) groups.
3543    
3544    4. Correct the implementation of \Z (it is permitted to match on the \n at the
3545    end of the subject) and add 5.005's \z, which really does match only at the
3546    very end of the subject.
3547    
3548    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3549    
3550    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3551    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3552    localized options. All options to pcre_study() were also removed.
3553    
3554    7. Add other new features from 5.005:
3555    
3556       $(?<=           positive lookbehind
3557       $(?<!           negative lookbehind
3558       (?imsx-imsx)    added the unsetting capability
3559                       such a setting is global if at outer level; local otherwise
3560       (?imsx-imsx:)   non-capturing groups with option setting
3561       (?(cond)re|re)  conditional pattern matching
3562    
3563       A backreference to itself in a repeated group matches the previous
3564       captured string.
3565    
3566    8. General tidying up of studying (both automatic and via "study")
3567    consequential on the addition of new assertions.
3568    
3569    9. As in 5.005, unlimited repeated groups that could match an empty substring
3570    are no longer faulted at compile time. Instead, the loop is forcibly broken at
3571    runtime if any iteration does actually match an empty substring.
3572    
3573    10. Include the RunTest script in the distribution.
3574    
3575    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3576    discrepancies, some of which were old and were also with respect to 5.004. They
3577    have now been fixed.
3578    
3579    
3580    Version 1.09 28-Apr-98
3581    ----------------------
3582    
3583    1. A negated single character class followed by a quantifier with a minimum
3584    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
3585    program crashes, or just wrong answers. This did not apply to negated classes
3586    containing more than one character, or to minima other than one.
3587    
3588    
3589  Version 1.08 27-Mar-98  Version 1.08 27-Mar-98
3590  ----------------------  ----------------------

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