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

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