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revision 39 by nigel, Sat Feb 24 21:39:13 2007 UTC revision 413 by ph10, Sat Apr 11 11:41:52 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.9 11-Apr-09
5    ---------------------
6    
7    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
8        (pcretest), all targets were linked against these libraries. This included
9        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
10        libraries. This caused unwanted dependencies to be created. This problem
11        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
12        pcretest is linked with readline.
13    
14    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
15        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
16        moved outside it again, because FALSE and TRUE are already defined in AIX,
17        but BOOL is not.
18    
19    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
20        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
21    
22    4.  The pcregrep documentation said spaces were inserted as well as colons (or
23        hyphens) following file names and line numbers when outputting matching
24        lines. This is not true; no spaces are inserted. I have also clarified the
25        wording for the --colour (or --color) option.
26    
27    5.  In pcregrep, when --colour was used with -o, the list of matching strings
28        was not coloured; this is different to GNU grep, so I have changed it to be
29        the same.
30    
31    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
32        each matching line was coloured. Now it goes on to look for further matches
33        of any of the test patterns, which is the same behaviour as GNU grep.
34    
35    7.  A pattern that could match an empty string could cause pcregrep to loop; it
36        doesn't make sense to accept an empty string match in pcregrep, so I have
37        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
38        seems to be how GNU grep behaves.
39    
40    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
41        start or after a newline", because the conditional assertion was not being
42        correctly handled. The rule now is that both the assertion and what follows
43        in the first alternative must satisfy the test.
44    
45    9.  If auto-callout was enabled in a pattern with a conditional group whose
46        condition was an assertion, PCRE could crash during matching, both with
47        pcre_exec() and pcre_dfa_exec().
48    
49    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
50        used for matching.
51    
52    11. Unicode property support in character classes was not working for
53        characters (bytes) greater than 127 when not in UTF-8 mode.
54    
55    12. Added the -M command line option to pcretest.
56    
57    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
58    
59    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
60    
61    16. Added comments and documentation about mis-use of no_arg in the C++
62        wrapper.
63    
64    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
65        from Martin Jerabek that uses macro names for all relevant character and
66        string constants.
67    
68    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
69        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
70        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
71        these, but not everybody uses configure.
72    
73    19. A conditional group that had only one branch was not being correctly
74        recognized as an item that could match an empty string. This meant that an
75        enclosing group might also not be so recognized, causing infinite looping
76        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
77        with the subject "ab", where knowledge that the repeated group can match
78        nothing is needed in order to break the loop.
79    
80    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
81        exec(), but without supplying a callout function, matching went wrong.
82    
83    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
84        leak if the size of the offset vector was greater than 30. When the vector
85        is smaller, the saved offsets during recursion go onto a local stack
86        vector, but for larger vectors malloc() is used. It was failing to free
87        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
88        error, in fact).
89    
90    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
91        heapframe that is used only when UTF-8 support is enabled. This caused no
92        problem, but was untidy.
93    
94    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
95        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
96        included within another project.
97    
98    24. Steven Van Ingelgem's patches to add more options to the CMake support,
99        slightly modified by me:
100    
101          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
102              not building pcregrep.
103    
104          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
105              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
106    
107    25. Forward references, both numeric and by name, in patterns that made use of
108        duplicate group numbers, could behave incorrectly or give incorrect errors,
109        because when scanning forward to find the reference group, PCRE was not
110        taking into account the duplicate group numbers. A pattern such as
111        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
112    
113    26. Changed a few more instances of "const unsigned char *" to USPTR, making
114        the feature of a custom pointer more persuasive (as requested by a user).
115    
116    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
117        pcretest.c, inside #ifndefs, because it seems they are sometimes already
118        pre-defined.
119    
120    28. Added support for (*UTF8) at the start of a pattern.
121    
122    29. Arrange for flags added by the "release type" setting in CMake to be shown
123        in the configuration summary.
124    
125    
126    Version 7.8 05-Sep-08
127    ---------------------
128    
129    1.  Replaced UCP searching code with optimized version as implemented for Ad
130        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
131        stage table and inline lookup instead of a function, giving speed ups of 2
132        to 5 times on some simple patterns that I tested. Permission was given to
133        distribute the MultiStage2.py script that generates the tables (it's not in
134        the tarball, but is in the Subversion repository).
135    
136    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
137        scripts.
138    
139    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
140        a group with a zero qualifier. The result of the study could be incorrect,
141        or the function might crash, depending on the pattern.
142    
143    4.  Caseless matching was not working for non-ASCII characters in back
144        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
145        It now works when Unicode Property Support is available.
146    
147    5.  In pcretest, an escape such as \x{de} in the data was always generating
148        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
149        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
150        truncation.
151    
152    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
153    
154    7.  Added two (int) casts to pcregrep when printing the difference of two
155        pointers, in case they are 64-bit values.
156    
157    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
158        test 2 if it fails.
159    
160    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
161        and a #define of that name to empty if it is not externally set. This is to
162        allow users of MSVC to set it if necessary.
163    
164    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
165        the convenience functions in the pcre_get.c source file.
166    
167    11. An option change at the start of a pattern that had top-level alternatives
168        could cause overwriting and/or a crash. This command provoked a crash in
169        some environments:
170    
171          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
172    
173        This potential security problem was recorded as CVE-2008-2371.
174    
175    12. For a pattern where the match had to start at the beginning or immediately
176        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
177        pcre_dfa_exec() could read past the end of the passed subject if there was
178        no match. To help with detecting such bugs (e.g. with valgrind), I modified
179        pcretest so that it places the subject at the end of its malloc-ed buffer.
180    
181    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
182        exec() might read past the end of the data buffer in UTF-8 mode.
183    
184    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
185        the data contained the byte 0x85 as part of a UTF-8 character within its
186        first line. This applied both to normal and DFA matching.
187    
188    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
189        /^[^d]*?$/8 failed to match "abc".
190    
191    16. Added a missing copyright notice to pcrecpp_internal.h.
192    
193    17. Make it more clear in the documentation that values returned from
194        pcre_exec() in ovector are byte offsets, not character counts.
195    
196    18. Tidied a few places to stop certain compilers from issuing warnings.
197    
198    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
199        supplied by Stefan Weber. I made a further small update for 7.8 because
200        there is a change of source arrangements: the pcre_searchfuncs.c module is
201        replaced by pcre_ucd.c.
202    
203    
204    Version 7.7 07-May-08
205    ---------------------
206    
207    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
208        a string to a long long, pretend we don't even have a long long." This is
209        done by checking for the strtoq, strtoll, and _strtoi64 functions.
210    
211    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
212        pre-7.6 versions, which defined a global no_arg variable instead of putting
213        it in the RE class. (See also #8 below.)
214    
215    3.  Remove a line of dead code, identified by coverity and reported by Nuno
216        Lopes.
217    
218    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
219    
220        (1) The include/exclude patterns were being applied to the whole pathnames
221            of files, instead of just to the final components.
222    
223        (2) If there was more than one level of directory, the subdirectories were
224            skipped unless they satisfied the include/exclude conditions. This is
225            inconsistent with GNU grep (and could even be seen as contrary to the
226            pcregrep specification - which I improved to make it absolutely clear).
227            The action now is always to scan all levels of directory, and just
228            apply the include/exclude patterns to regular files.
229    
230    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
231        --exclude_dir in the tests to avoid scanning .svn directories.
232    
233    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
234        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
235        doesn't support NULs in patterns.
236    
237    7.  Added some missing "const"s to declarations of static tables in
238        pcre_compile.c and pcre_dfa_exec.c.
239    
240    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
241        caused by fix #2  above. (Subsequently also a second patch to fix the
242        first patch. And a third patch - this was a messy problem.)
243    
244    9.  Applied Craig's patch to remove the use of push_back().
245    
246    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
247        matching function regexec().
248    
249    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
250        which, however, unlike Perl's \g{...}, are subroutine calls, not back
251        references. PCRE supports relative numbers with this syntax (I don't think
252        Oniguruma does).
253    
254    12. Previously, a group with a zero repeat such as (...){0} was completely
255        omitted from the compiled regex. However, this means that if the group
256        was called as a subroutine from elsewhere in the pattern, things went wrong
257        (an internal error was given). Such groups are now left in the compiled
258        pattern, with a new opcode that causes them to be skipped at execution
259        time.
260    
261    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
262        to the way PCRE behaves:
263    
264        (a) A lone ] character is dis-allowed (Perl treats it as data).
265    
266        (b) A back reference to an unmatched subpattern matches an empty string
267            (Perl fails the current match path).
268    
269        (c) A data ] in a character class must be notated as \] because if the
270            first data character in a class is ], it defines an empty class. (In
271            Perl it is not possible to have an empty class.) The empty class []
272            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
273            The negative empty class [^] matches any one character, independently
274            of the DOTALL setting.
275    
276    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
277        non-existent subpattern following a character class starting with ']' and
278        containing () gave an internal compiling error instead of "reference to
279        non-existent subpattern". Fortunately, when the pattern did exist, the
280        compiled code was correct. (When scanning forwards to check for the
281        existencd of the subpattern, it was treating the data ']' as terminating
282        the class, so got the count wrong. When actually compiling, the reference
283        was subsequently set up correctly.)
284    
285    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
286        it was being rejected as not supported by pcre_dfa_exec(), even though
287        other assertions are supported. I have made pcre_dfa_exec() support
288        (*FAIL).
289    
290    16. The implementation of 13c above involved the invention of a new opcode,
291        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
292        cannot be changed at match time, I realized I could make a small
293        improvement to matching performance by compiling OP_ALLANY instead of
294        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
295        on the OP_ANY path.
296    
297    17. Compiling pcretest on Windows with readline support failed without the
298        following two fixes: (1) Make the unistd.h include conditional on
299        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
300    
301    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
302        ncurses library to be included for pcretest when ReadLine support is
303        requested, but also to allow for it to be overridden. This patch came from
304        Daniel Bergström.
305    
306    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
307        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
308        any errors with the current Unicode tables. Thanks to Peter Kankowski for
309        spotting this.
310    
311    
312    Version 7.6 28-Jan-08
313    ---------------------
314    
315    1.  A character class containing a very large number of characters with
316        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
317        overflow.
318    
319    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
320        HAVE_LONG_LONG is not defined.
321    
322    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
323        bring them up to date and include new features. This patch includes:
324    
325        - Fixed PH's badly added libz and libbz2 support.
326        - Fixed a problem with static linking.
327        - Added pcredemo. [But later removed - see 7 below.]
328        - Fixed dftables problem and added an option.
329        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
330            HAVE_LONG_LONG.
331        - Added readline support for pcretest.
332        - Added an listing of the option settings after cmake has run.
333    
334    4.  A user submitted a patch to Makefile that makes it easy to create
335        "pcre.dll" under mingw when using Configure/Make. I added stuff to
336        Makefile.am that cause it to include this special target, without
337        affecting anything else. Note that the same mingw target plus all
338        the other distribution libraries and programs are now supported
339        when configuring with CMake (see 6 below) instead of with
340        Configure/Make.
341    
342    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
343        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
344        exported in the Windows port". It has not yet been confirmed that the patch
345        solves the problem, but it does no harm.
346    
347    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
348        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
349        with CMake, and also correct the comment about stack recursion.
350    
351    7.  Remove the automatic building of pcredemo from the ./configure system and
352        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
353        of a program that users should build themselves after PCRE is installed, so
354        building it automatically is not really right. What is more, it gave
355        trouble in some build environments.
356    
357    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
358    
359    
360    Version 7.5 10-Jan-08
361    ---------------------
362    
363    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
364        values in parens when parsing an RE using the C++ wrapper."
365    
366    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
367        Characters greater than 255 were excluded from the class instead of being
368        included.
369    
370    3.  The same bug as (2) above applied to negated POSIX classes such as
371        [:^space:].
372    
373    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
374        defined or documented. It seems to have been a typo for PCRE_STATIC, so
375        I have changed it.
376    
377    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
378        first named subpattern) and a construct such as (?&a) would reference the
379        first named subpattern whose name started with "a" (in other words, the
380        length check was missing). Both these problems are fixed. "Subpattern name
381        expected" is now given for (?&) (a zero-length name), and this patch also
382        makes it give the same error for \k'' (previously it complained that that
383        was a reference to a non-existent subpattern).
384    
385    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
386        this is right because (?- can be followed by option settings as well as by
387        digits. I have, however, made the messages clearer.
388    
389    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
390        than the number used in the conditional) now cause a compile-time error.
391        This is actually not compatible with Perl, which accepts such patterns, but
392        treats the conditional as always being FALSE (as PCRE used to), but it
393        seems to me that giving a diagnostic is better.
394    
395    8.  Change "alphameric" to the more common word "alphanumeric" in comments
396        and messages.
397    
398    9.  Fix two occurrences of "backslash" in comments that should have been
399        "backspace".
400    
401    10. Remove two redundant lines of code that can never be obeyed (their function
402        was moved elsewhere).
403    
404    11. The program that makes PCRE's Unicode character property table had a bug
405        which caused it to generate incorrect table entries for sequences of
406        characters that have the same character type, but are in different scripts.
407        It amalgamated them into a single range, with the script of the first of
408        them. In other words, some characters were in the wrong script. There were
409        thirteen such cases, affecting characters in the following ranges:
410    
411          U+002b0 - U+002c1
412          U+0060c - U+0060d
413          U+0061e - U+00612
414          U+0064b - U+0065e
415          U+0074d - U+0076d
416          U+01800 - U+01805
417          U+01d00 - U+01d77
418          U+01d9b - U+01dbf
419          U+0200b - U+0200f
420          U+030fc - U+030fe
421          U+03260 - U+0327f
422          U+0fb46 - U+0fbb1
423          U+10450 - U+1049d
424    
425    12. The -o option (show only the matching part of a line) for pcregrep was not
426        compatible with GNU grep in that, if there was more than one match in a
427        line, it showed only the first of them. It now behaves in the same way as
428        GNU grep.
429    
430    13. If the -o and -v options were combined for pcregrep, it printed a blank
431        line for every non-matching line. GNU grep prints nothing, and pcregrep now
432        does the same. The return code can be used to tell if there were any
433        non-matching lines.
434    
435    14. Added --file-offsets and --line-offsets to pcregrep.
436    
437    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
438        infinitely looping recursion. The bug was that positive lookaheads were not
439        being skipped when checking for a possible empty match (negative lookaheads
440        and both kinds of lookbehind were skipped).
441    
442    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
443        inclusion of <windows.h> to before rather than after the definition of
444        INVALID_FILE_ATTRIBUTES (patch from David Byron).
445    
446    17. Specifying a possessive quantifier with a specific limit for a Unicode
447        character property caused pcre_compile() to compile bad code, which led at
448        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
449        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
450        caused the error; without that there was no problem.
451    
452    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
453    
454    19. Added --enable-pcretest-libreadline.
455    
456    20. In pcrecpp.cc, the variable 'count' was incremented twice in
457        RE::GlobalReplace(). As a result, the number of replacements returned was
458        double what it should be. I removed one of the increments, but Craig sent a
459        later patch that removed the other one (the right fix) and added unit tests
460        that check the return values (which was not done before).
461    
462    21. Several CMake things:
463    
464        (1) Arranged that, when cmake is used on Unix, the libraries end up with
465            the names libpcre and libpcreposix, not just pcre and pcreposix.
466    
467        (2) The above change means that pcretest and pcregrep are now correctly
468            linked with the newly-built libraries, not previously installed ones.
469    
470        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
471    
472    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
473        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
474        UTF-8 newline character). The key issue is that the pattern starts .*;
475        this means that the match must be either at the beginning, or after a
476        newline. The bug was in the code for advancing after a failed match and
477        checking that the new position followed a newline. It was not taking
478        account of UTF-8 characters correctly.
479    
480    23. PCRE was behaving differently from Perl in the way it recognized POSIX
481        character classes. PCRE was not treating the sequence [:...:] as a
482        character class unless the ... were all letters. Perl, however, seems to
483        allow any characters between [: and :], though of course it rejects as
484        unknown any "names" that contain non-letters, because all the known class
485        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
486        for example, whereas PCRE did not - it did not recognize a POSIX character
487        class. This seemed a bit dangerous, so the code has been changed to be
488        closer to Perl. The behaviour is not identical to Perl, because PCRE will
489        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
490        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
491        Perl does, and where it didn't before.
492    
493    24. Rewrite so as to remove the single use of %n from pcregrep because in some
494        Windows environments %n is disabled by default.
495    
496    
497    Version 7.4 21-Sep-07
498    ---------------------
499    
500    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
501        means that a class such as [\s] counted as "explicit reference to CR or
502        LF". That isn't really right - the whole point of the change was to try to
503        help when there was an actual mention of one of the two characters. So now
504        the change happens only if \r or \n (or a literal CR or LF) character is
505        encountered.
506    
507    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
508        of both had grown to the point where there were only 3 bits left.
509        Fortunately, there was spare space in the data structure, and so I have
510        moved the internal flags into a new 16-bit field to free up more option
511        bits.
512    
513    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
514        but did not set the internal JCHANGED flag - either of these is enough to
515        control the way the "get" function works - but the PCRE_INFO_JCHANGED
516        facility is supposed to tell if (?J) was ever used, so now (?J) at the
517        start sets both bits.
518    
519    4.  Added options (at build time, compile time, exec time) to change \R from
520        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
521    
522    5.  doc/pcresyntax.html was missing from the distribution.
523    
524    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
525        compatibility, even though it is no longer used.
526    
527    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
528        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
529        windows.h file is present (where different names are used). [This was
530        reversed later after testing - see 16 below.]
531    
532    8.  Changed all #include <config.h> to #include "config.h". There were also
533        some further <pcre.h> cases that I changed to "pcre.h".
534    
535    9.  When pcregrep was used with the --colour option, it missed the line ending
536        sequence off the lines that it output.
537    
538    10. It was pointed out to me that arrays of string pointers cause lots of
539        relocations when a shared library is dynamically loaded. A technique of
540        using a single long string with a table of offsets can drastically reduce
541        these. I have refactored PCRE in four places to do this. The result is
542        dramatic:
543    
544          Originally:                          290
545          After changing UCP table:            187
546          After changing error message table:   43
547          After changing table of "verbs"       36
548          After changing table of Posix names   22
549    
550        Thanks to the folks working on Gregex for glib for this insight.
551    
552    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
553        unicode-properties was also set.
554    
555    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
556    
557    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
558        checked only for CRLF.
559    
560    14. Added casts to pcretest.c to avoid compiler warnings.
561    
562    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
563    
564    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
565        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
566        entirely. This removes changes made in 7 above.
567    
568    17. The CMake files have been updated, and there is now more information about
569        building with CMake in the NON-UNIX-USE document.
570    
571    
572    Version 7.3 28-Aug-07
573    ---------------------
574    
575     1. In the rejigging of the build system that eventually resulted in 7.1, the
576        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
577        brackets there is not right, since it causes compilers to look for an
578        installed pcre.h, not the version that is in the source that is being
579        compiled (which of course may be different). I have changed it back to:
580    
581          #include "pcre.h"
582    
583        I have a vague recollection that the change was concerned with compiling in
584        different directories, but in the new build system, that is taken care of
585        by the VPATH setting the Makefile.
586    
587     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
588        when the subject happened to end in the byte 0x85 (e.g. if the last
589        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
590        characters but of course it shouldn't be taken as a newline when it is part
591        of another character. The bug was that, for an unlimited repeat of . in
592        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
593        characters when looking for a newline.
594    
595     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
596    
597     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
598        in debug output.
599    
600     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
601        long printing in the pcrecpp unittest when running under MinGW.
602    
603     6. ESC_K was left out of the EBCDIC table.
604    
605     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
606        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
607        limit also applies to "virtual nesting" when a pattern is recursive, and in
608        this case 1000 isn't so big. I have been able to remove this limit at the
609        expense of backing off one optimization in certain circumstances. Normally,
610        when pcre_exec() would call its internal match() function recursively and
611        immediately return the result unconditionally, it uses a "tail recursion"
612        feature to save stack. However, when a subpattern that can match an empty
613        string has an unlimited repetition quantifier, it no longer makes this
614        optimization. That gives it a stack frame in which to save the data for
615        checking that an empty string has been matched. Previously this was taken
616        from the 1000-entry workspace that had been reserved. So now there is no
617        explicit limit, but more stack is used.
618    
619     8. Applied Daniel's patches to solve problems with the import/export magic
620        syntax that is required for Windows, and which was going wrong for the
621        pcreposix and pcrecpp parts of the library. These were overlooked when this
622        problem was solved for the main library.
623    
624     9. There were some crude static tests to avoid integer overflow when computing
625        the size of patterns that contain repeated groups with explicit upper
626        limits. As the maximum quantifier is 65535, the maximum group length was
627        set at 30,000 so that the product of these two numbers did not overflow a
628        32-bit integer. However, it turns out that people want to use groups that
629        are longer than 30,000 bytes (though not repeat them that many times).
630        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
631        made it possible to implement the integer overflow checks in a much more
632        dynamic way, which I have now done. The artificial limitation on group
633        length has been removed - we now have only the limit on the total length of
634        the compiled pattern, which depends on the LINK_SIZE setting.
635    
636    10. Fixed a bug in the documentation for get/copy named substring when
637        duplicate names are permitted. If none of the named substrings are set, the
638        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
639        empty string.
640    
641    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
642        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
643        because the ] is interpreted as the first data character and the
644        terminating ] is not found. PCRE has been made compatible with Perl in this
645        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
646        cause memory overwriting.
647    
648    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
649        string has been matched (to stop an infinite loop). It was not recognizing
650        a conditional subpattern that could match an empty string if that
651        subpattern was within another subpattern. For example, it looped when
652        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
653        condition was not nested. This bug has been fixed.
654    
655    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
656        past the start of the subject in the presence of bytes with the top bit
657        set, for example "\x8aBCD".
658    
659    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
660        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
661    
662    14. Optimized (?!) to (*FAIL).
663    
664    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
665        This restricts code points to be within the range 0 to 0x10FFFF, excluding
666        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
667        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
668        does: it's just the validity check that is more restrictive.
669    
670    16. Inserted checks for integer overflows during escape sequence (backslash)
671        processing, and also fixed erroneous offset values for syntax errors during
672        backslash processing.
673    
674    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
675        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
676    
677    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
678        caused an overrun.
679    
680    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
681        something other than just ASCII characters) inside a group that had an
682        unlimited repeat caused a loop at compile time (while checking to see
683        whether the group could match an empty string).
684    
685    20. Debugging a pattern containing \p or \P could cause a crash. For example,
686        [\P{Any}] did so. (Error in the code for printing property names.)
687    
688    21. An orphan \E inside a character class could cause a crash.
689    
690    22. A repeated capturing bracket such as (A)? could cause a wild memory
691        reference during compilation.
692    
693    23. There are several functions in pcre_compile() that scan along a compiled
694        expression for various reasons (e.g. to see if it's fixed length for look
695        behind). There were bugs in these functions when a repeated \p or \P was
696        present in the pattern. These operators have additional parameters compared
697        with \d, etc, and these were not being taken into account when moving along
698        the compiled data. Specifically:
699    
700        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
701            length.
702    
703        (b) An item such as \pL+ within a repeated group could cause crashes or
704            loops.
705    
706        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
707            "reference to non-existent subpattern" error.
708    
709        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
710    
711    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
712        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
713    
714    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
715    
716    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
717        character were causing crashes (broken optimization).
718    
719    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
720        \p or \P) caused a compile-time loop.
721    
722    28. More problems have arisen in unanchored patterns when CRLF is a valid line
723        break. For example, the unstudied pattern [\r\n]A does not match the string
724        "\r\nA" because change 7.0/46 below moves the current point on by two
725        characters after failing to match at the start. However, the pattern \nA
726        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
727        the same is true. There doesn't seem any very clean way out of this, but
728        what I have chosen to do makes the common cases work: PCRE now takes note
729        of whether there can be an explicit match for \r or \n anywhere in the
730        pattern, and if so, 7.0/46 no longer applies. As part of this change,
731        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
732        pattern has explicit CR or LF references.
733    
734    29. Added (*CR) etc for changing newline setting at start of pattern.
735    
736    
737    Version 7.2 19-Jun-07
738    ---------------------
739    
740     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
741        which is apparently normally available under Windows.
742    
743     2. Re-jig the pcregrep tests with different newline settings in an attempt
744        to make them independent of the local environment's newline setting.
745    
746     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
747    
748     4. Some of the "internals" tests were previously cut out when the link size
749        was not 2, because the output contained actual offsets. The recent new
750        "Z" feature of pcretest means that these can be cut out, making the tests
751        usable with all link sizes.
752    
753     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
754        stack recursion. This gives a massive performance boost under BSD, but just
755        a small improvement under Linux. However, it saves one field in the frame
756        in all cases.
757    
758     6. Added more features from the forthcoming Perl 5.10:
759    
760        (a) (?-n) (where n is a string of digits) is a relative subroutine or
761            recursion call. It refers to the nth most recently opened parentheses.
762    
763        (b) (?+n) is also a relative subroutine call; it refers to the nth next
764            to be opened parentheses.
765    
766        (c) Conditions that refer to capturing parentheses can be specified
767            relatively, for example, (?(-2)... or (?(+3)...
768    
769        (d) \K resets the start of the current match so that everything before
770            is not part of it.
771    
772        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
773    
774        (f) \g{name} is another synonym - part of Perl 5.10's unification of
775            reference syntax.
776    
777        (g) (?| introduces a group in which the numbering of parentheses in each
778            alternative starts with the same number.
779    
780        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
781    
782     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
783        PCRE_INFO_JCHANGED.
784    
785     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
786        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
787        for detecting groups that can match an empty string.
788    
789     9. A pattern with a very large number of alternatives (more than several
790        hundred) was running out of internal workspace during the pre-compile
791        phase, where pcre_compile() figures out how much memory will be needed. A
792        bit of new cunning has reduced the workspace needed for groups with
793        alternatives. The 1000-alternative test pattern now uses 12 bytes of
794        workspace instead of running out of the 4096 that are available.
795    
796    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
797    
798    11. Applied patch from Google to remove an optimization that didn't quite work.
799        The report of the bug said:
800    
801          pcrecpp::RE("a*").FullMatch("aaa") matches, while
802          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
803          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
804    
805    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
806        it matched the wrong number of bytes.
807    
808    
809    Version 7.1 24-Apr-07
810    ---------------------
811    
812     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
813        that is more "standard", making use of automake and other Autotools. There
814        is some re-arrangement of the files and adjustment of comments consequent
815        on this.
816    
817     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
818        for recursive directory scanning broke on some systems because the files
819        are not scanned in any specific order and on different systems the order
820        was different. A call to "sort" has been inserted into RunGrepTest for the
821        approprate test as a short-term fix. In the longer term there may be an
822        alternative.
823    
824     3. I had an email from Eric Raymond about problems translating some of PCRE's
825        man pages to HTML (despite the fact that I distribute HTML pages, some
826        people do their own conversions for various reasons). The problems
827        concerned the use of low-level troff macros .br and .in. I have therefore
828        removed all such uses from the man pages (some were redundant, some could
829        be replaced by .nf/.fi pairs). The 132html script that I use to generate
830        HTML has been updated to handle .nf/.fi and to complain if it encounters
831        .br or .in.
832    
833     4. Updated comments in configure.ac that get placed in config.h.in and also
834        arranged for config.h to be included in the distribution, with the name
835        config.h.generic, for the benefit of those who have to compile without
836        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
837    
838     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
839        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
840        makevp.bat for the current PCRE, using the additional files
841        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
842    
843     6. A Windows user reported a minor discrepancy with test 2, which turned out
844        to be caused by a trailing space on an input line that had got lost in his
845        copy. The trailing space was an accident, so I've just removed it.
846    
847     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
848        that is needed.
849    
850     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
851        as "const" (a) because they are and (b) because it helps the PHP
852        maintainers who have recently made a script to detect big data structures
853        in the php code that should be moved to the .rodata section. I remembered
854        to update Builducptable as well, so it won't revert if ucptable.h is ever
855        re-created.
856    
857     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
858        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
859        order to be able to cut out the UTF-8 tables in the latter when UTF-8
860        support is not required. This saves 1.5-2K of code, which is important in
861        some applications.
862    
863        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
864        so as not to refer to the tables, even though these functions will never be
865        called when UTF-8 support is disabled. Otherwise there are problems with a
866        shared library.
867    
868    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
869    
870        (a) It was defining its arguments as char * instead of void *.
871    
872        (b) It was assuming that all moves were upwards in memory; this was true
873            a long time ago when I wrote it, but is no longer the case.
874    
875        The emulated memove() is provided for those environments that have neither
876        memmove() nor bcopy(). I didn't think anyone used it these days, but that
877        is clearly not the case, as these two bugs were recently reported.
878    
879    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
880        and Detrail to create the HTML documentation, the .txt form of the man
881        pages, and it removes trailing spaces from listed files. It also creates
882        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
883        case, it wraps all the #defines with #ifndefs. This script should be run
884        before "make dist".
885    
886    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
887        with Unicode property support.
888    
889        (a) For a maximizing quantifier, if the two different cases of the
890            character were of different lengths in their UTF-8 codings (there are
891            some cases like this - I found 11), and the matching function had to
892            back up over a mixture of the two cases, it incorrectly assumed they
893            were both the same length.
894    
895        (b) When PCRE was configured to use the heap rather than the stack for
896            recursion during matching, it was not correctly preserving the data for
897            the other case of a UTF-8 character when checking ahead for a match
898            while processing a minimizing repeat. If the check also involved
899            matching a wide character, but failed, corruption could cause an
900            erroneous result when trying to check for a repeat of the original
901            character.
902    
903    13. Some tidying changes to the testing mechanism:
904    
905        (a) The RunTest script now detects the internal link size and whether there
906            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
907            values substituted by "configure". (The RunGrepTest script already did
908            this for UTF-8.) The configure.ac script no longer substitutes the
909            relevant variables.
910    
911        (b) The debugging options /B and /D in pcretest show the compiled bytecode
912            with length and offset values. This means that the output is different
913            for different internal link sizes. Test 2 is skipped for link sizes
914            other than 2 because of this, bypassing the problem. Unfortunately,
915            there was also a test in test 3 (the locale tests) that used /B and
916            failed for link sizes other than 2. Rather than cut the whole test out,
917            I have added a new /Z option to pcretest that replaces the length and
918            offset values with spaces. This is now used to make test 3 independent
919            of link size. (Test 2 will be tidied up later.)
920    
921    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
922        segmentation fault instead of returning the appropriate error message.
923    
924    15. In multiline mode when the newline sequence was set to "any", the pattern
925        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
926        This doesn't seem right; it now treats the CRLF combination as the line
927        ending, and so does not match in that case. It's only a pattern such as ^$
928        that would hit this one: something like ^ABC$ would have failed after \r
929        and then tried again after \r\n.
930    
931    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
932        in an attempt to make files that differ only in their line terminators
933        compare equal. This works on Linux.
934    
935    17. Under certain error circumstances pcregrep might try to free random memory
936        as it exited. This is now fixed, thanks to valgrind.
937    
938    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
939        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
940        was because its rules for how to advance for /g after matching an empty
941        string at the end of a line did not allow for this case. They now check for
942        it specially.
943    
944    20. pcretest is supposed to handle patterns and data of any length, by
945        extending its buffers when necessary. It was getting this wrong when the
946        buffer for a data line had to be extended.
947    
948    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
949        CRLF as a newline sequence.
950    
951    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
952        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
953        I have nevertheless tidied it up.
954    
955    23. Added some casts to kill warnings from HP-UX ia64 compiler.
956    
957    24. Added a man page for pcre-config.
958    
959    
960    Version 7.0 19-Dec-06
961    ---------------------
962    
963     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
964        moving to gcc 4.1.1.
965    
966     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
967        sys/time.h, which is documented as needed for this function. It doesn't
968        seem to matter on Linux, but it showed up on some releases of OS X.
969    
970     3. It seems that there are systems where bytes whose values are greater than
971        127 match isprint() in the "C" locale. The "C" locale should be the
972        default when a C program starts up. In most systems, only ASCII printing
973        characters match isprint(). This difference caused the output from pcretest
974        to vary, making some of the tests fail. I have changed pcretest so that:
975    
976        (a) When it is outputting text in the compiled version of a pattern, bytes
977            other than 32-126 are always shown as hex escapes.
978    
979        (b) When it is outputting text that is a matched part of a subject string,
980            it does the same, unless a different locale has been set for the match
981            (using the /L modifier). In this case, it uses isprint() to decide.
982    
983     4. Fixed a major bug that caused incorrect computation of the amount of memory
984        required for a compiled pattern when options that changed within the
985        pattern affected the logic of the preliminary scan that determines the
986        length. The relevant options are -x, and -i in UTF-8 mode. The result was
987        that the computed length was too small. The symptoms of this bug were
988        either the PCRE error "internal error: code overflow" from pcre_compile(),
989        or a glibc crash with a message such as "pcretest: free(): invalid next
990        size (fast)". Examples of patterns that provoked this bug (shown in
991        pcretest format) are:
992    
993          /(?-x: )/x
994          /(?x)(?-x: \s*#\s*)/
995          /((?i)[\x{c0}])/8
996          /(?i:[\x{c0}])/8
997    
998        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
999        is now done differently.
1000    
1001     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1002        wrapper classes; (b) implement a new function in the C++ scanner that is
1003        more efficient than the old way of doing things because it avoids levels of
1004        recursion in the regex matching; (c) add a paragraph to the documentation
1005        for the FullMatch() function.
1006    
1007     6. The escape sequence \n was being treated as whatever was defined as
1008        "newline". Not only was this contrary to the documentation, which states
1009        that \n is character 10 (hex 0A), but it also went horribly wrong when
1010        "newline" was defined as CRLF. This has been fixed.
1011    
1012     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1013        was being set to -1 for the "end of line" case (supposedly a value that no
1014        character can have). Though this value is never used (the check for end of
1015        line is "zero bytes in current character"), it caused compiler complaints.
1016        I've changed it to 0xffffffff.
1017    
1018     8. In pcre_version.c, the version string was being built by a sequence of
1019        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1020        string (as it is for production releases) called a macro with an empty
1021        argument. The C standard says the result of this is undefined. The gcc
1022        compiler treats it as an empty string (which was what was wanted) but it is
1023        reported that Visual C gives an error. The source has been hacked around to
1024        avoid this problem.
1025    
1026     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1027        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1028        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1029        of them did).
1030    
1031    10. Originally, pcretest opened its input and output without "b"; then I was
1032        told that "b" was needed in some environments, so it was added for release
1033        5.0 to both the input and output. (It makes no difference on Unix-like
1034        systems.) Later I was told that it is wrong for the input on Windows. I've
1035        now abstracted the modes into two macros, to make it easier to fiddle with
1036        them, and removed "b" from the input mode under Windows.
1037    
1038    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1039    
1040    12. Added -help and --help to pcretest as an official way of being reminded
1041        of the options.
1042    
1043    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1044        and pcrecpp.cc because they annoy compilers at high warning levels.
1045    
1046    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1047    
1048    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1049        scripts are not C programs :-) and which was not noticed because it works
1050        on Linux.
1051    
1052    16. pcretest is supposed to handle any length of pattern and data line (as one
1053        line or as a continued sequence of lines) by extending its input buffer if
1054        necessary. This feature was broken for very long pattern lines, leading to
1055        a string of junk being passed to pcre_compile() if the pattern was longer
1056        than about 50K.
1057    
1058    17. I have done a major re-factoring of the way pcre_compile() computes the
1059        amount of memory needed for a compiled pattern. Previously, there was code
1060        that made a preliminary scan of the pattern in order to do this. That was
1061        OK when PCRE was new, but as the facilities have expanded, it has become
1062        harder and harder to keep it in step with the real compile phase, and there
1063        have been a number of bugs (see for example, 4 above). I have now found a
1064        cunning way of running the real compile function in a "fake" mode that
1065        enables it to compute how much memory it would need, while actually only
1066        ever using a few hundred bytes of working memory and without too many
1067        tests of the mode. This should make future maintenance and development
1068        easier. A side effect of this work is that the limit of 200 on the nesting
1069        depth of parentheses has been removed (though this was never a serious
1070        limitation, I suspect). However, there is a downside: pcre_compile() now
1071        runs more slowly than before (30% or more, depending on the pattern). I
1072        hope this isn't a big issue. There is no effect on runtime performance.
1073    
1074    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1075        newline (only possible for the last line of a file) and it was a
1076        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1077    
1078    19. Added additional timing features to pcretest. (1) The -tm option now times
1079        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1080        separate command line item, by a number that specifies the number of
1081        repeats to use when timing. The default is 50000; this gives better
1082        precision, but takes uncomfortably long for very large patterns.
1083    
1084    20. Extended pcre_study() to be more clever in cases where a branch of a
1085        subpattern has no definite first character. For example, (a*|b*)[cd] would
1086        previously give no result from pcre_study(). Now it recognizes that the
1087        first character must be a, b, c, or d.
1088    
1089    21. There was an incorrect error "recursive call could loop indefinitely" if
1090        a subpattern (or the entire pattern) that was being tested for matching an
1091        empty string contained only one non-empty item after a nested subpattern.
1092        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1093        incorrectly, because the \d was being skipped in the check.
1094    
1095    22. The pcretest program now has a new pattern option /B and a command line
1096        option -b, which is equivalent to adding /B to every pattern. This causes
1097        it to show the compiled bytecode, without the additional information that
1098        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1099        is the same as /B/I).
1100    
1101    23. A new optimization is now able automatically to treat some sequences such
1102        as a*b as a*+b. More specifically, if something simple (such as a character
1103        or a simple class like \d) has an unlimited quantifier, and is followed by
1104        something that cannot possibly match the quantified thing, the quantifier
1105        is automatically "possessified".
1106    
1107    24. A recursive reference to a subpattern whose number was greater than 39
1108        went wrong under certain circumstances in UTF-8 mode. This bug could also
1109        have affected the operation of pcre_study().
1110    
1111    25. Realized that a little bit of performance could be had by replacing
1112        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1113    
1114    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1115    
1116    27. Possessive quantifiers such as a++ were previously implemented by turning
1117        them into atomic groups such as ($>a+). Now they have their own opcodes,
1118        which improves performance. This includes the automatically created ones
1119        from 23 above.
1120    
1121    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1122        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1123        the first matched character to be a colon. This applied both to named and
1124        numbered groups.
1125    
1126    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1127    
1128    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1129        building PCRE on Windows easier, so I have included it in the distribution.
1130    
1131    31. There is now a check in pcretest against a ridiculously large number being
1132        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1133        loop, the loop is abandoned.
1134    
1135    32. Forward references to subpatterns in conditions such as (?(2)...) where
1136        subpattern 2 is defined later cause pcre_compile() to search forwards in
1137        the pattern for the relevant set of parentheses. This search went wrong
1138        when there were unescaped parentheses in a character class, parentheses
1139        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1140    
1141    33. "Subroutine" calls and backreferences were previously restricted to
1142        referencing subpatterns earlier in the regex. This restriction has now
1143        been removed.
1144    
1145    34. Added a number of extra features that are going to be in Perl 5.10. On the
1146        whole, these are just syntactic alternatives for features that PCRE had
1147        previously implemented using the Python syntax or my own invention. The
1148        other formats are all retained for compatibility.
1149    
1150        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1151            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1152            also .NET compatible.
1153    
1154        (b) A recursion or subroutine call to a named group can now be defined as
1155            (?&name) as well as (?P>name).
1156    
1157        (c) A backreference to a named group can now be defined as \k<name> or
1158            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1159            5.10, are also .NET compatible.
1160    
1161        (d) A conditional reference to a named group can now use the syntax
1162            (?(<name>) or (?('name') as well as (?(name).
1163    
1164        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1165            groups (named and numbered) that are never evaluated inline, but can be
1166            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1167            is always false. There may be only one alternative in such a group.
1168    
1169        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1170            as the simple (?(R). The condition is true only if the most recent
1171            recursion is that of the given number or name. It does not search out
1172            through the entire recursion stack.
1173    
1174        (g) The escape \gN or \g{N} has been added, where N is a positive or
1175            negative number, specifying an absolute or relative reference.
1176    
1177    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1178        some "unreachable code" warnings.
1179    
1180    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1181        things, this adds five new scripts.
1182    
1183    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1184        There were also incompatibilities regarding the handling of \Q..\E inside
1185        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1186        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1187    
1188    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1189        matches an empty string, and forcibly breaks the loop. There were bugs in
1190        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1191        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1192        separate and independent bugs (that affected different cases) have been
1193        fixed.
1194    
1195    39. Refactored the code to abolish the use of different opcodes for small
1196        capturing bracket numbers. This is a tidy that I avoided doing when I
1197        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1198        The new approach is not only tidier, it makes it possible to reduce the
1199        memory needed to fix the previous bug (38).
1200    
1201    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1202        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1203        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1204        mode.
1205    
1206    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1207        report.
1208    
1209    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1210        copy construction and assignment in the C++ wrapper.
1211    
1212    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1213        couple of bugs that could have given wrong results in the "--newline=crlf"
1214        case.
1215    
1216    44. Added a number of casts and did some reorganization of signed/unsigned int
1217        variables following suggestions from Dair Grant. Also renamed the variable
1218        "this" as "item" because it is a C++ keyword.
1219    
1220    45. Arranged for dftables to add
1221    
1222          #include "pcre_internal.h"
1223    
1224        to pcre_chartables.c because without it, gcc 4.x may remove the array
1225        definition from the final binary if PCRE is built into a static library and
1226        dead code stripping is activated.
1227    
1228    46. For an unanchored pattern, if a match attempt fails at the start of a
1229        newline sequence, and the newline setting is CRLF or ANY, and the next two
1230        characters are CRLF, advance by two characters instead of one.
1231    
1232    
1233    Version 6.7 04-Jul-06
1234    ---------------------
1235    
1236     1. In order to handle tests when input lines are enormously long, pcretest has
1237        been re-factored so that it automatically extends its buffers when
1238        necessary. The code is crude, but this _is_ just a test program. The
1239        default size has been increased from 32K to 50K.
1240    
1241     2. The code in pcre_study() was using the value of the re argument before
1242        testing it for NULL. (Of course, in any sensible call of the function, it
1243        won't be NULL.)
1244    
1245     3. The memmove() emulation function in pcre_internal.h, which is used on
1246        systems that lack both memmove() and bcopy() - that is, hardly ever -
1247        was missing a "static" storage class specifier.
1248    
1249     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1250        containing an extended class (one that cannot be represented by a bitmap
1251        because it contains high-valued characters or Unicode property items, e.g.
1252        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1253        pattern, but PCRE should not loop if you do not (it no longer does).
1254        [Detail: two cases were found: (a) a repeated subpattern containing an
1255        extended class; (b) a recursive reference to a subpattern that followed a
1256        previous extended class. It wasn't skipping over the extended class
1257        correctly when UTF-8 mode was not set.]
1258    
1259     5. A negated single-character class was not being recognized as fixed-length
1260        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1261        compile error "lookbehind assertion is not fixed length".
1262    
1263     6. The RunPerlTest auxiliary script was showing an unexpected difference
1264        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1265        write a Perl script that can interpret lines of an input file either as
1266        byte characters or as UTF-8, which is what "perltest" was being required to
1267        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1268        can't do is switch easily at run time between having the "use utf8;" pragma
1269        or not. In the end, I fudged it by using the RunPerlTest script to insert
1270        "use utf8;" explicitly for the UTF-8 tests.
1271    
1272     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1273        the end of the subject string, contrary to the documentation and to what
1274        Perl does. This was true of both matching functions. Now it matches only at
1275        the start of the subject and immediately after *internal* newlines.
1276    
1277     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1278        a pointer to an int instead of a pointer to an unsigned long int. This
1279        caused problems on 64-bit systems.
1280    
1281     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1282        instance of the 'standard' template library not being so standard".
1283    
1284    10. There was no check on the number of named subpatterns nor the maximum
1285        length of a subpattern name. The product of these values is used to compute
1286        the size of the memory block for a compiled pattern. By supplying a very
1287        long subpattern name and a large number of named subpatterns, the size
1288        computation could be caused to overflow. This is now prevented by limiting
1289        the length of names to 32 characters, and the number of named subpatterns
1290        to 10,000.
1291    
1292    11. Subpatterns that are repeated with specific counts have to be replicated in
1293        the compiled pattern. The size of memory for this was computed from the
1294        length of the subpattern and the repeat count. The latter is limited to
1295        65535, but there was no limit on the former, meaning that integer overflow
1296        could in principle occur. The compiled length of a repeated subpattern is
1297        now limited to 30,000 bytes in order to prevent this.
1298    
1299    12. Added the optional facility to have named substrings with the same name.
1300    
1301    13. Added the ability to use a named substring as a condition, using the
1302        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1303        are numbers (not recommended). Forward references are permitted.
1304    
1305    14. Added forward references in named backreferences (if you see what I mean).
1306    
1307    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1308        pattern could run off the end of the subject. For example, the pattern
1309        "(?s)(.{1,5})"8 did this with the subject "ab".
1310    
1311    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1312        PCRE_CASELESS was set when matching characters that were quantified with ?
1313        or *.
1314    
1315    17. A character class other than a single negated character that had a minimum
1316        but no maximum quantifier - for example [ab]{6,} - was not handled
1317        correctly by pce_dfa_exec(). It would match only one character.
1318    
1319    18. A valid (though odd) pattern that looked like a POSIX character
1320        class but used an invalid character after [ (for example [[,abc,]]) caused
1321        pcre_compile() to give the error "Failed: internal error: code overflow" or
1322        in some cases to crash with a glibc free() error. This could even happen if
1323        the pattern terminated after [[ but there just happened to be a sequence of
1324        letters, a binary zero, and a closing ] in the memory that followed.
1325    
1326    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1327        over the years. Originally (before any Unicode support), just the bottom 8
1328        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1329        output from "man perlunicode" includes this:
1330    
1331          The regular expression compiler produces polymorphic opcodes.  That
1332          is, the pattern adapts to the data and automatically switches to
1333          the Unicode character scheme when presented with Unicode data--or
1334          instead uses a traditional byte scheme when presented with byte
1335          data.
1336    
1337        Sadly, a wide octal escape does not cause a switch, and in a string with
1338        no other multibyte characters, these octal escapes are treated as before.
1339        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1340        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1341        Unicode string.
1342    
1343        I have not perpetrated such confusion in PCRE. Up till now, it took just
1344        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1345        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1346        translate to the appropriate multibyte character.
1347    
1348    29. Applied some refactoring to reduce the number of warnings from Microsoft
1349        and Borland compilers. This has included removing the fudge introduced
1350        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1351        a warning about an unused variable.
1352    
1353    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1354        characters since release 4.0, because Perl (from release 5.004) does not.
1355        [Or at least, is documented not to: some releases seem to be in conflict
1356        with the documentation.] However, when a pattern was studied with
1357        pcre_study() and all its branches started with \s, PCRE still included VT
1358        as a possible starting character. Of course, this did no harm; it just
1359        caused an unnecessary match attempt.
1360    
1361    22. Removed a now-redundant internal flag bit that recorded the fact that case
1362        dependency changed within the pattern. This was once needed for "required
1363        byte" processing, but is no longer used. This recovers a now-scarce options
1364        bit. Also moved the least significant internal flag bit to the most-
1365        significant bit of the word, which was not previously used (hangover from
1366        the days when it was an int rather than a uint) to free up another bit for
1367        the future.
1368    
1369    23. Added support for CRLF line endings as well as CR and LF. As well as the
1370        default being selectable at build time, it can now be changed at runtime
1371        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1372        specify that it is scanning data with non-default line endings.
1373    
1374    24. Changed the definition of CXXLINK to make it agree with the definition of
1375        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1376    
1377    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1378        recursions. This makes a big different to stack usage for some patterns.
1379    
1380    26. If a subpattern containing a named recursion or subroutine reference such
1381        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1382        the space required for the compiled pattern went wrong and gave too small a
1383        value. Depending on the environment, this could lead to "Failed: internal
1384        error: code overflow at offset 49" or "glibc detected double free or
1385        corruption" errors.
1386    
1387    27. Applied patches from Google (a) to support the new newline modes and (b) to
1388        advance over multibyte UTF-8 characters in GlobalReplace.
1389    
1390    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1391        difference for some implementation of PCRE in some Windows version.
1392    
1393    29. Added some extra testing facilities to pcretest:
1394    
1395        \q<number>   in a data line sets the "match limit" value
1396        \Q<number>   in a data line sets the "match recursion limt" value
1397        -S <number>  sets the stack size, where <number> is in megabytes
1398    
1399        The -S option isn't available for Windows.
1400    
1401    
1402    Version 6.6 06-Feb-06
1403    ---------------------
1404    
1405     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1406        in pcreposix.h. I have copied the definition from pcre.h.
1407    
1408     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1409        because pcre.h is no longer a built file.
1410    
1411     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1412        not normally included in the compiled code.
1413    
1414    
1415    Version 6.5 01-Feb-06
1416    ---------------------
1417    
1418     1. When using the partial match feature with pcre_dfa_exec(), it was not
1419        anchoring the second and subsequent partial matches at the new starting
1420        point. This could lead to incorrect results. For example, with the pattern
1421        /1234/, partially matching against "123" and then "a4" gave a match.
1422    
1423     2. Changes to pcregrep:
1424    
1425        (a) All non-match returns from pcre_exec() were being treated as failures
1426            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1427            error message is output. Some extra information is given for the
1428            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1429            probably the only errors that are likely to be caused by users (by
1430            specifying a regex that has nested indefinite repeats, for instance).
1431            If there are more than 20 of these errors, pcregrep is abandoned.
1432    
1433        (b) A binary zero was treated as data while matching, but terminated the
1434            output line if it was written out. This has been fixed: binary zeroes
1435            are now no different to any other data bytes.
1436    
1437        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1438            used to set a locale for matching. The --locale=xxxx long option has
1439            been added (no short equivalent) to specify a locale explicitly on the
1440            pcregrep command, overriding the environment variables.
1441    
1442        (d) When -B was used with -n, some line numbers in the output were one less
1443            than they should have been.
1444    
1445        (e) Added the -o (--only-matching) option.
1446    
1447        (f) If -A or -C was used with -c (count only), some lines of context were
1448            accidentally printed for the final match.
1449    
1450        (g) Added the -H (--with-filename) option.
1451    
1452        (h) The combination of options -rh failed to suppress file names for files
1453            that were found from directory arguments.
1454    
1455        (i) Added the -D (--devices) and -d (--directories) options.
1456    
1457        (j) Added the -F (--fixed-strings) option.
1458    
1459        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1460    
1461        (l) Added the --colo(u)r option.
1462    
1463        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1464            is not present by default.
1465    
1466     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1467        items such as (?R) or (?1), when the recursion could match a number of
1468        alternatives. If it matched one of the alternatives, but subsequently,
1469        outside the recursion, there was a failure, the code tried to back up into
1470        the recursion. However, because of the way PCRE is implemented, this is not
1471        possible, and the result was an incorrect result from the match.
1472    
1473        In order to prevent this happening, the specification of recursion has
1474        been changed so that all such subpatterns are automatically treated as
1475        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1476    
1477     4. I had overlooked the fact that, in some locales, there are characters for
1478        which isalpha() is true but neither isupper() nor islower() are true. In
1479        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1480        and ordfeminine) are like this. This affected the treatment of \w and \W
1481        when they appeared in character classes, but not when they appeared outside
1482        a character class. The bit map for "word" characters is now created
1483        separately from the results of isalnum() instead of just taking it from the
1484        upper, lower, and digit maps. (Plus the underscore character, of course.)
1485    
1486     5. The above bug also affected the handling of POSIX character classes such as
1487        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1488        permanent tables. Instead, the bit maps for such a class were previously
1489        created as the appropriate unions of the upper, lower, and digit bitmaps.
1490        Now they are created by subtraction from the [[:word:]] class, which has
1491        its own bitmap.
1492    
1493     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1494        It is created by subtracting the vertical space characters (\x09, \x0a,
1495        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1496        subtraction was done in the overall bitmap for a character class, meaning
1497        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1498        be recognized. This bug has been fixed.
1499    
1500     7. Patches from the folks at Google:
1501    
1502          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1503          real life, but is still worth protecting against".
1504    
1505          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1506          regular expressions".
1507    
1508          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1509          have it.
1510    
1511          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1512          "configure" and the latter not, in order to fix a problem somebody had
1513          with compiling the Arg class on HP-UX.
1514    
1515          (e) Improve the error-handling of the C++ wrapper a little bit.
1516    
1517          (f) New tests for checking recursion limiting.
1518    
1519     8. The pcre_memmove() function, which is used only if the environment does not
1520        have a standard memmove() function (and is therefore rarely compiled),
1521        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1522        returning a result (though PCRE never actually uses the result).
1523    
1524     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1525        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1526        returned instead of calling malloc() with an overflowing number that would
1527        most likely cause subsequent chaos.
1528    
1529    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1530    
1531    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1532        with this option is matched, the nmatch and pmatch options of regexec() are
1533        ignored.
1534    
1535    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1536        provided in case anyone wants to the the POSIX interface with UTF-8
1537        strings.
1538    
1539    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1540        C++ linking (needed for some HP-UX environments).
1541    
1542    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1543        (unused parameter) and in the pcre_printint() function (omitted "default"
1544        switch label when the default is to do nothing).
1545    
1546    15. Added some code to make it possible, when PCRE is compiled as a C++
1547        library, to replace subject pointers for pcre_exec() with a smart pointer
1548        class, thus making it possible to process discontinuous strings.
1549    
1550    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1551        much the same function. They were added by different people who were trying
1552        to make PCRE easy to compile on non-Unix systems. It has been suggested
1553        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1554        for compiling on Windows systems. I have therefore replaced it with
1555        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1556        defaults to "extern" for C or "extern C" for C++, which works fine on
1557        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1558        SCOPE with something explicit in config.h. In addition:
1559    
1560        (a) pcreposix.h still had just "extern" instead of either of these macros;
1561            I have replaced it with PCRE_DATA_SCOPE.
1562    
1563        (b) Functions such as _pcre_xclass(), which are internal to the library,
1564            but external in the C sense, all had PCRE_EXPORT in their definitions.
1565            This is apparently wrong for the Windows case, so I have removed it.
1566            (It makes no difference on Unix-like systems.)
1567    
1568    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1569        of recursive calls to match(). This is different to MATCH_LIMIT because
1570        that limits the total number of calls to match(), not all of which increase
1571        the depth of recursion. Limiting the recursion depth limits the amount of
1572        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1573        when PCRE is compiled, and changed at run time. A patch from Google adds
1574        this functionality to the C++ interface.
1575    
1576    18. Changes to the handling of Unicode character properties:
1577    
1578        (a) Updated the table to Unicode 4.1.0.
1579    
1580        (b) Recognize characters that are not in the table as "Cn" (undefined).
1581    
1582        (c) I revised the way the table is implemented to a much improved format
1583            which includes recognition of ranges. It now supports the ranges that
1584            are defined in UnicodeData.txt, and it also amalgamates other
1585            characters into ranges. This has reduced the number of entries in the
1586            table from around 16,000 to around 3,000, thus reducing its size
1587            considerably. I realized I did not need to use a tree structure after
1588            all - a binary chop search is just as efficient. Having reduced the
1589            number of entries, I extended their size from 6 bytes to 8 bytes to
1590            allow for more data.
1591    
1592        (d) Added support for Unicode script names via properties such as \p{Han}.
1593    
1594    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1595        matching that character.
1596    
1597    20. When matching a repeated Unicode property with a minimum greater than zero,
1598        (for example \pL{2,}), PCRE could look past the end of the subject if it
1599        reached it while seeking the minimum number of characters. This could
1600        happen only if some of the characters were more than one byte long, because
1601        there is a check for at least the minimum number of bytes.
1602    
1603    21. Refactored the implementation of \p and \P so as to be more general, to
1604        allow for more different types of property in future. This has changed the
1605        compiled form incompatibly. Anybody with saved compiled patterns that use
1606        \p or \P will have to recompile them.
1607    
1608    22. Added "Any" and "L&" to the supported property types.
1609    
1610    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1611        but give a compile time error if the value is greater than 0xff.
1612    
1613    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1614        accidentally not being installed or uninstalled.
1615    
1616    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1617        made were to insert the current release number. This seemed silly, because
1618        it made things harder for people building PCRE on systems that don't run
1619        "configure". I have turned pcre.h into a distributed file, no longer built
1620        by "configure", with the version identification directly included. There is
1621        no longer a pcre.h.in file.
1622    
1623        However, this change necessitated a change to the pcre-config script as
1624        well. It is built from pcre-config.in, and one of the substitutions was the
1625        release number. I have updated configure.ac so that ./configure now finds
1626        the release number by grepping pcre.h.
1627    
1628    26. Added the ability to run the tests under valgrind.
1629    
1630    
1631    Version 6.4 05-Sep-05
1632    ---------------------
1633    
1634     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1635        "--" to be printed when multiple files were scanned, even when none of the
1636        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1637        consider it to be a bug, and have restored the previous behaviour.
1638    
1639     2. A couple of code tidies to get rid of compiler warnings.
1640    
1641     3. The pcretest program used to cheat by referring to symbols in the library
1642        whose names begin with _pcre_. These are internal symbols that are not
1643        really supposed to be visible externally, and in some environments it is
1644        possible to suppress them. The cheating is now confined to including
1645        certain files from the library's source, which is a bit cleaner.
1646    
1647     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1648        file's purpose clearer.
1649    
1650     5. Reorganized pcre_ucp_findchar().
1651    
1652    
1653    Version 6.3 15-Aug-05
1654    ---------------------
1655    
1656     1. The file libpcre.pc.in did not have general read permission in the tarball.
1657    
1658     2. There were some problems when building without C++ support:
1659    
1660        (a) If C++ support was not built, "make install" and "make test" still
1661            tried to test it.
1662    
1663        (b) There were problems when the value of CXX was explicitly set. Some
1664            changes have been made to try to fix these, and ...
1665    
1666        (c) --disable-cpp can now be used to explicitly disable C++ support.
1667    
1668        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1669            backslash in a target when C++ was disabled. This confuses some
1670            versions of "make", apparently. Using an intermediate variable solves
1671            this. (Same for CPP_LOBJ.)
1672    
1673     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1674        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1675        necessary on certain architectures.
1676    
1677     4. Added a setting of -export-symbols-regex to the link command to remove
1678        those symbols that are exported in the C sense, but actually are local
1679        within the library, and not documented. Their names all begin with
1680        "_pcre_". This is not a perfect job, because (a) we have to except some
1681        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1682        available (and never for static libraries). I have made a note to try to
1683        find a way round (a) in the future.
1684    
1685    
1686    Version 6.2 01-Aug-05
1687    ---------------------
1688    
1689     1. There was no test for integer overflow of quantifier values. A construction
1690        such as {1111111111111111} would give undefined results. What is worse, if
1691        a minimum quantifier for a parenthesized subpattern overflowed and became
1692        negative, the calculation of the memory size went wrong. This could have
1693        led to memory overwriting.
1694    
1695     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1696    
1697     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1698        operating environments where this matters.
1699    
1700     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1701        PCRE options from within the C++ wrapper.
1702    
1703     5. Named capturing subpatterns were not being correctly counted when a pattern
1704        was compiled. This caused two problems: (a) If there were more than 100
1705        such subpatterns, the calculation of the memory needed for the whole
1706        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1707        back references of the form \12, where the number was greater than 9, were
1708        not recognized as back references, even though there were sufficient
1709        previous subpatterns.
1710    
1711     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1712        versions of gcc, e.g. 2.95.4.
1713    
1714    
1715    Version 6.1 21-Jun-05
1716    ---------------------
1717    
1718     1. There was one reference to the variable "posix" in pcretest.c that was not
1719        surrounded by "#if !defined NOPOSIX".
1720    
1721     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1722        the cross-check on the old pcre_info() function, for the benefit of the
1723        cut-down version of PCRE that is currently imported into Exim.
1724    
1725     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1726        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1727        patterns that start (?i) but I don't think that matters. The use of (?i) is
1728        just an example; this all applies to the other options as well.
1729    
1730     4. Since libtool seems to echo the compile commands it is issuing, the output
1731        from "make" can be reduced a bit by putting "@" in front of each libtool
1732        compile command.
1733    
1734     5. Patch from the folks at Google for configure.in to be a bit more thorough
1735        in checking for a suitable C++ installation before trying to compile the
1736        C++ stuff. This should fix a reported problem when a compiler was present,
1737        but no suitable headers.
1738    
1739     6. The man pages all had just "PCRE" as their title. I have changed them to
1740        be the relevant file name. I have also arranged that these names are
1741        retained in the file doc/pcre.txt, which is a concatenation in text format
1742        of all the man pages except the little individual ones for each function.
1743    
1744     7. The NON-UNIX-USE file had not been updated for the different set of source
1745        files that come with release 6. I also added a few comments about the C++
1746        wrapper.
1747    
1748    
1749    Version 6.0 07-Jun-05
1750    ---------------------
1751    
1752     1. Some minor internal re-organization to help with my DFA experiments.
1753    
1754     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1755        didn't matter for the library itself when fully configured, but did matter
1756        when compiling without UCP support, or within Exim, where the ucp files are
1757        not imported.
1758    
1759     3. Refactoring of the library code to split up the various functions into
1760        different source modules. The addition of the new DFA matching code (see
1761        below) to a single monolithic source would have made it really too
1762        unwieldy, quite apart from causing all the code to be include in a
1763        statically linked application, when only some functions are used. This is
1764        relevant even without the DFA addition now that patterns can be compiled in
1765        one application and matched in another.
1766    
1767        The downside of splitting up is that there have to be some external
1768        functions and data tables that are used internally in different modules of
1769        the library but which are not part of the API. These have all had their
1770        names changed to start with "_pcre_" so that they are unlikely to clash
1771        with other external names.
1772    
1773     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1774        a different (DFA) algorithm. Although it is slower than the original
1775        function, it does have some advantages for certain types of matching
1776        problem.
1777    
1778     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1779        including restarting after a partial match.
1780    
1781     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1782        defined when compiling for Windows was sent to me. I have put it into the
1783        code, though I have no means of testing or verifying it.
1784    
1785     7. Added the pcre_refcount() auxiliary function.
1786    
1787     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1788        match before or at the first newline in the subject string. In pcretest,
1789        the /f option on a pattern can be used to set this.
1790    
1791     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1792        would behave wrongly. This has been present in PCRE since release 4.0.
1793    
1794    10. A number of changes to the pcregrep command:
1795    
1796        (a) Refactored how -x works; insert ^(...)$ instead of setting
1797            PCRE_ANCHORED and checking the length, in preparation for adding
1798            something similar for -w.
1799    
1800        (b) Added the -w (match as a word) option.
1801    
1802        (c) Refactored the way lines are read and buffered so as to have more
1803            than one at a time available.
1804    
1805        (d) Implemented a pcregrep test script.
1806    
1807        (e) Added the -M (multiline match) option. This allows patterns to match
1808            over several lines of the subject. The buffering ensures that at least
1809            8K, or the rest of the document (whichever is the shorter) is available
1810            for matching (and similarly the previous 8K for lookbehind assertions).
1811    
1812        (f) Changed the --help output so that it now says
1813    
1814              -w, --word-regex(p)
1815    
1816            instead of two lines, one with "regex" and the other with "regexp"
1817            because that confused at least one person since the short forms are the
1818            same. (This required a bit of code, as the output is generated
1819            automatically from a table. It wasn't just a text change.)
1820    
1821        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1822            option but starts with a hyphen. Could be a pattern or a path name
1823            starting with a hyphen, for instance.
1824    
1825        (h) "-" can be given as a file name to represent stdin.
1826    
1827        (i) When file names are being printed, "(standard input)" is used for
1828            the standard input, for compatibility with GNU grep. Previously
1829            "<stdin>" was used.
1830    
1831        (j) The option --label=xxx can be used to supply a name to be used for
1832            stdin when file names are being printed. There is no short form.
1833    
1834        (k) Re-factored the options decoding logic because we are going to add
1835            two more options that take data. Such options can now be given in four
1836            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1837    
1838        (l) Added the -A, -B, and -C options for requesting that lines of context
1839            around matches be printed.
1840    
1841        (m) Added the -L option to print the names of files that do not contain
1842            any matching lines, that is, the complement of -l.
1843    
1844        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1845            continue to scan other files.
1846    
1847        (o) The -s option was incorrectly implemented. For compatibility with other
1848            greps, it now suppresses the error message for a non-existent or non-
1849            accessible file (but not the return code). There is a new option called
1850            -q that suppresses the output of matching lines, which was what -s was
1851            previously doing.
1852    
1853        (p) Added --include and --exclude options to specify files for inclusion
1854            and exclusion when recursing.
1855    
1856    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1857        Hopefully, it now does.
1858    
1859    12. Missing cast in pcre_study().
1860    
1861    13. Added an "uninstall" target to the makefile.
1862    
1863    14. Replaced "extern" in the function prototypes in Makefile.in with
1864        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1865        world, but is set differently for Windows.
1866    
1867    15. Added a second compiling function called pcre_compile2(). The only
1868        difference is that it has an extra argument, which is a pointer to an
1869        integer error code. When there is a compile-time failure, this is set
1870        non-zero, in addition to the error test pointer being set to point to an
1871        error message. The new argument may be NULL if no error number is required
1872        (but then you may as well call pcre_compile(), which is now just a
1873        wrapper). This facility is provided because some applications need a
1874        numeric error indication, but it has also enabled me to tidy up the way
1875        compile-time errors are handled in the POSIX wrapper.
1876    
1877    16. Added VPATH=.libs to the makefile; this should help when building with one
1878        prefix path and installing with another. (Or so I'm told by someone who
1879        knows more about this stuff than I do.)
1880    
1881    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1882        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1883        match everything, including newlines. This is not POSIX-compatible, but
1884        somebody wanted the feature. From pcretest it can be activated by using
1885        both the P and the s flags.
1886    
1887    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1888    
1889    19. libpcre.pc was being incorrectly installed as executable.
1890    
1891    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1892        it now also looks for '\r' so that it will work unmodified on Windows.
1893    
1894    21. Added Google's contributed C++ wrapper to the distribution.
1895    
1896    22. Added some untidy missing memory free() calls in pcretest, to keep
1897        Electric Fence happy when testing.
1898    
1899    
1900    
1901    Version 5.0 13-Sep-04
1902    ---------------------
1903    
1904     1. Internal change: literal characters are no longer packed up into items
1905        containing multiple characters in a single byte-string. Each character
1906        is now matched using a separate opcode. However, there may be more than one
1907        byte in the character in UTF-8 mode.
1908    
1909     2. The pcre_callout_block structure has two new fields: pattern_position and
1910        next_item_length. These contain the offset in the pattern to the next match
1911        item, and its length, respectively.
1912    
1913     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1914        insertion of callouts before each pattern item. Added the /C option to
1915        pcretest to make use of this.
1916    
1917     4. On the advice of a Windows user, the lines
1918    
1919          #if defined(_WIN32) || defined(WIN32)
1920          _setmode( _fileno( stdout ), 0x8000 );
1921          #endif  /* defined(_WIN32) || defined(WIN32) */
1922    
1923        have been added to the source of pcretest. This apparently does useful
1924        magic in relation to line terminators.
1925    
1926     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1927        for the benefit of those environments where the "b" makes a difference.
1928    
1929     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1930        to know about it. I have put a hack into configure.in that adds in code
1931        to set GCC=yes if CC=icc. This seems to end up at a point in the
1932        generated configure script that is early enough to affect the setting of
1933        compiler options, which is what is needed, but I have no means of testing
1934        whether it really works. (The user who reported this had patched the
1935        generated configure script, which of course I cannot do.)
1936    
1937        LATER: After change 22 below (new libtool files), the configure script
1938        seems to know about icc (and also ecc). Therefore, I have commented out
1939        this hack in configure.in.
1940    
1941     7. Added support for pkg-config (2 patches were sent in).
1942    
1943     8. Negated POSIX character classes that used a combination of internal tables
1944        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1945        [[:^ascii]]. Typically, they would match almost any characters. The other
1946        POSIX classes were not broken in this way.
1947    
1948     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1949        to find the match, as PCRE was deluded into thinking that the match had to
1950        start at the start point or following a newline. The same bug applied to
1951        patterns with negative forward assertions or any backward assertions
1952        preceding ".*" at the start, unless the pattern required a fixed first
1953        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1954    
1955    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1956        starting at the last subject character, bytes beyond the end of the subject
1957        string were read.
1958    
1959    11. Renamed the variable "class" as "classbits" to make life easier for C++
1960        users. (Previously there was a macro definition, but it apparently wasn't
1961        enough.)
1962    
1963    12. Added the new field "tables" to the extra data so that tables can be passed
1964        in at exec time, or the internal tables can be re-selected. This allows
1965        a compiled regex to be saved and re-used at a later time by a different
1966        program that might have everything at different addresses.
1967    
1968    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1969        -R library as well as a -L library.
1970    
1971    14. The debugging options of pcretest (-d on the command line or D on a
1972        pattern) showed incorrect output for anything following an extended class
1973        that contained multibyte characters and which was followed by a quantifier.
1974    
1975    15. Added optional support for general category Unicode character properties
1976        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1977        support. It adds about 90K to the size of the library. The meanings of the
1978        inbuilt class escapes such as \d and \s have NOT been changed.
1979    
1980    16. Updated pcredemo.c to include calls to free() to release the memory for the
1981        compiled pattern.
1982    
1983    17. The generated file chartables.c was being created in the source directory
1984        instead of in the building directory. This caused the build to fail if the
1985        source directory was different from the building directory, and was
1986        read-only.
1987    
1988    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1989        file. No doubt somebody will tell me if they don't make sense... Also added
1990        Dan Mooney's comments about building on OpenVMS.
1991    
1992    19. Added support for partial matching via the PCRE_PARTIAL option for
1993        pcre_exec() and the \P data escape in pcretest.
1994    
1995    20. Extended pcretest with 3 new pattern features:
1996    
1997        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1998              write the compiled pattern to the file whose name is "rest-of-line".
1999              This is a straight binary dump of the data, with the saved pointer to
2000              the character tables forced to be NULL. The study data, if any, is
2001              written too. After writing, pcretest reads a new pattern.
2002    
2003        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2004              compiled pattern from the given file. There must not be any
2005              occurrences of "<" in the file name (pretty unlikely); if there are,
2006              pcretest will instead treat the initial "<" as a pattern delimiter.
2007              After reading in the pattern, pcretest goes on to read data lines as
2008              usual.
2009    
2010        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2011              and 16-bit fields in a compiled pattern, to simulate a pattern that
2012              was compiled on a host of opposite endianness.
2013    
2014    21. The pcre-exec() function can now cope with patterns that were compiled on
2015        hosts of opposite endianness, with this restriction:
2016    
2017          As for any compiled expression that is saved and used later, the tables
2018          pointer field cannot be preserved; the extra_data field in the arguments
2019          to pcre_exec() should be used to pass in a tables address if a value
2020          other than the default internal tables were used at compile time.
2021    
2022    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2023        now diagnosed as an error. Previously, most of the time, a negative number
2024        would have been treated as zero, but if in addition "ovector" was passed as
2025        NULL, a crash could occur.
2026    
2027    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2028        new versions from the libtool 1.5 distribution (the last one is a copy of
2029        a file called libtool.m4). This seems to have fixed the need to patch
2030        "configure" to support Darwin 1.3 (which I used to do). However, I still
2031        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2032        workstation).
2033    
2034    24. Changed the PCRE licence to be the more standard "BSD" licence.
2035    
2036    
2037    Version 4.5 01-Dec-03
2038    ---------------------
2039    
2040     1. There has been some re-arrangement of the code for the match() function so
2041        that it can be compiled in a version that does not call itself recursively.
2042        Instead, it keeps those local variables that need separate instances for
2043        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2044        needs to "recurse". Keeping track of where control must go is done by means
2045        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2046        hide most of the details from the main code, and operates only if
2047        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2048        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2049        operating.
2050    
2051        To make it easier for callers to provide specially tailored get/free
2052        functions for this usage, two new functions, pcre_stack_malloc, and
2053        pcre_stack_free, are used. They are always called in strict stacking order,
2054        and the size of block requested is always the same.
2055    
2056        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2057        PCRE has been compiled to use the stack or the heap for recursion. The
2058        -C option of pcretest uses this to show which version is compiled.
2059    
2060        A new data escape \S, is added to pcretest; it causes the amounts of store
2061        obtained and freed by both kinds of malloc/free at match time to be added
2062        to the output.
2063    
2064     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2065        what's available on my current Linux desktop machine.
2066    
2067     3. When matching a UTF-8 string, the test for a valid string at the start has
2068        been extended. If start_offset is not zero, PCRE now checks that it points
2069        to a byte that is the start of a UTF-8 character. If not, it returns
2070        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2071        this is necessary because there may be backward assertions in the pattern.
2072        When matching the same subject several times, it may save resources to use
2073        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2074    
2075     4. The code for checking the validity of UTF-8 strings has been tightened so
2076        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2077        containing "overlong sequences".
2078    
2079     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2080        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2081        should have been "&", but it just so happened that all the cases this let
2082        through by mistake were picked up later in the function.
2083    
2084     6. I had used a variable called "isblank" - this is a C99 function, causing
2085        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2086    
2087     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2088        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2089        so the version is shown; (c) stop "make test" echoing "./RunTest".
2090    
2091     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2092    
2093     9. The prototype for memmove() for systems that don't have it was using
2094        size_t, but the inclusion of the header that defines size_t was later. I've
2095        moved the #includes for the C headers earlier to avoid this.
2096    
2097    10. Added some adjustments to the code to make it easier to compiler on certain
2098        special systems:
2099    
2100          (a) Some "const" qualifiers were missing.
2101          (b) Added the macro EXPORT before all exported functions; by default this
2102              is defined to be empty.
2103          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2104              that it reads its output file name as an argument instead of writing
2105              to the standard output and assuming this can be redirected.
2106    
2107    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2108        class containing characters with values greater than 255, PCRE compilation
2109        went into a loop.
2110    
2111    12. A recursive reference to a subpattern that was within another subpattern
2112        that had a minimum quantifier of zero caused PCRE to crash. For example,
2113        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2114        recursion. If the recursively-called subpattern itself had a zero repeat,
2115        that was OK.
2116    
2117    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2118        buffer into which it was copied (for escape processing) was still set at
2119        1024, so long lines caused crashes.
2120    
2121    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2122        "internal error: code overflow...". This applied to any character class
2123        that was followed by a possessive quantifier.
2124    
2125    15. Modified the Makefile to add libpcre.la as a prerequisite for
2126        libpcreposix.la because I was told this is needed for a parallel build to
2127        work.
2128    
2129    16. If a pattern that contained .* following optional items at the start was
2130        studied, the wrong optimizing data was generated, leading to matching
2131        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2132        matching string must start with a or b or c. The correct conclusion for
2133        this pattern is that a match can start with any character.
2134    
2135    
2136    Version 4.4 13-Aug-03
2137    ---------------------
2138    
2139     1. In UTF-8 mode, a character class containing characters with values between
2140        127 and 255 was not handled correctly if the compiled pattern was studied.
2141        In fixing this, I have also improved the studying algorithm for such
2142        classes (slightly).
2143    
2144     2. Three internal functions had redundant arguments passed to them. Removal
2145        might give a very teeny performance improvement.
2146    
2147     3. Documentation bug: the value of the capture_top field in a callout is *one
2148        more than* the number of the hightest numbered captured substring.
2149    
2150     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2151        in incorrectly linking with a previously installed version. They now link
2152        explicitly with libpcre.la.
2153    
2154     5. configure.in no longer needs to recognize Cygwin specially.
2155    
2156     6. A problem in pcre.in for Windows platforms is fixed.
2157    
2158     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2159        pcretest, it used to include the size of the study block as part of its
2160        output. Unfortunately, the structure contains a field that has a different
2161        size on different hardware architectures. This meant that the tests that
2162        showed this size failed. As the block is currently always of a fixed size,
2163        this information isn't actually particularly useful in pcretest output, so
2164        I have just removed it.
2165    
2166     8. Three pre-processor statements accidentally did not start in column 1.
2167        Sadly, there are *still* compilers around that complain, even though
2168        standard C has not required this for well over a decade. Sigh.
2169    
2170     9. In pcretest, the code for checking callouts passed small integers in the
2171        callout_data field, which is a void * field. However, some picky compilers
2172        complained about the casts involved for this on 64-bit systems. Now
2173        pcretest passes the address of the small integer instead, which should get
2174        rid of the warnings.
2175    
2176    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2177        both compile and run time, and gives an error if an invalid UTF-8 sequence
2178        is found. There is a option for disabling this check in cases where the
2179        string is known to be correct and/or the maximum performance is wanted.
2180    
2181    11. In response to a bug report, I changed one line in Makefile.in from
2182    
2183            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2184        to
2185            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2186    
2187        to look similar to other lines, but I have no way of telling whether this
2188        is the right thing to do, as I do not use Windows. No doubt I'll get told
2189        if it's wrong...
2190    
2191    
2192    Version 4.3 21-May-03
2193    ---------------------
2194    
2195    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2196       Makefile.
2197    
2198    2. Some refactoring to improve the quality of the code:
2199    
2200       (i)   The utf8_table... variables are now declared "const".
2201    
2202       (ii)  The code for \cx, which used the "case flipping" table to upper case
2203             lower case letters, now just substracts 32. This is ASCII-specific,
2204             but the whole concept of \cx is ASCII-specific, so it seems
2205             reasonable.
2206    
2207       (iii) PCRE was using its character types table to recognize decimal and
2208             hexadecimal digits in the pattern. This is silly, because it handles
2209             only 0-9, a-f, and A-F, but the character types table is locale-
2210             specific, which means strange things might happen. A private
2211             table is now used for this - though it costs 256 bytes, a table is
2212             much faster than multiple explicit tests. Of course, the standard
2213             character types table is still used for matching digits in subject
2214             strings against \d.
2215    
2216       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2217             ending in _t are). So I've renamed it as ESC_tee.
2218    
2219    3. The first argument for regexec() in the POSIX wrapper should have been
2220       defined as "const".
2221    
2222    4. Changed pcretest to use malloc() for its buffers so that they can be
2223       Electric Fenced for debugging.
2224    
2225    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2226       to read one or more bytes before the start of the subject string. Often this
2227       had no effect on PCRE's behaviour, but in some circumstances it could
2228       provoke a segmentation fault.
2229    
2230    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2231       to try to read one or more bytes before the start of the subject string.
2232    
2233    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2234       UTF-8 support could misbehave in various ways if the subject string
2235       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2236       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2237       back over UTF-8 characters.)
2238    
2239    
2240    Version 4.2 14-Apr-03
2241    ---------------------
2242    
2243    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2244    
2245    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2246         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2247         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2248         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2249         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2250           and BUILD_EXEEXT
2251         Note: automatic setting of the BUILD variables is not yet working
2252         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2253           compile-time but not at link-time
2254         [LINK]: use for linking executables only
2255         make different versions for Windows and non-Windows
2256         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2257           libraries
2258         [LINK_FOR_BUILD]: new variable
2259         [OBJEXT]: use throughout
2260         [EXEEXT]: use throughout
2261         <winshared>: new target
2262         <wininstall>: new target
2263         <dftables.o>: use native compiler
2264         <dftables>: use native linker
2265         <install>: handle Windows platform correctly
2266         <clean>: ditto
2267         <check>: ditto
2268         copy DLL to top builddir before testing
2269    
2270       As part of these changes, -no-undefined was removed again. This was reported
2271       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2272       in any case.
2273    
2274    3. Some tidies to get rid of compiler warnings:
2275    
2276       . In the match_data structure, match_limit was an unsigned long int, whereas
2277         match_call_count was an int. I've made them both unsigned long ints.
2278    
2279       . In pcretest the fact that a const uschar * doesn't automatically cast to
2280         a void * provoked a warning.
2281    
2282       . Turning on some more compiler warnings threw up some "shadow" variables
2283         and a few more missing casts.
2284    
2285    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2286       option, a class that contained a single character with a value between 128
2287       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2288    
2289    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2290       option, a class that contained several characters, but with at least one
2291       whose value was between 128 and 255 caused PCRE to crash.
2292    
2293    
2294    Version 4.1 12-Mar-03
2295    ---------------------
2296    
2297    1. Compiling with gcc -pedantic found a couple of places where casts were
2298    needed, and a string in dftables.c that was longer than standard compilers are
2299    required to support.
2300    
2301    2. Compiling with Sun's compiler found a few more places where the code could
2302    be tidied up in order to avoid warnings.
2303    
2304    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2305    first of these names is deprecated in the latest Autoconf in favour of the name
2306    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2307    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2308    analogy I have changed it to CFLAGS_FOR_BUILD.
2309    
2310    4. Added -no-undefined to the linking command in the Makefile, because this is
2311    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2312    linking step for the pcreposix library.
2313    
2314    5. PCRE was failing to diagnose the case of two named groups with the same
2315    name.
2316    
2317    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2318    literal character that is needed in the subject for a match, and scans along to
2319    ensure that it is present before embarking on the full matching process. This
2320    saves time in cases of nested unlimited repeats that are never going to match.
2321    Problem: the scan can take a lot of time if the subject is very long (e.g.
2322    megabytes), thus penalizing straightforward matches. It is now done only if the
2323    amount of subject to be scanned is less than 1000 bytes.
2324    
2325    7. A lesser problem with the same optimization is that it was recording the
2326    first character of an anchored pattern as "needed", thus provoking a search
2327    right along the subject, even when the first match of the pattern was going to
2328    fail. The "needed" character is now not set for anchored patterns, unless it
2329    follows something in the pattern that is of non-fixed length. Thus, it still
2330    fulfils its original purpose of finding quick non-matches in cases of nested
2331    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2332    
2333    
2334    Version 4.0 17-Feb-03
2335    ---------------------
2336    
2337    1. If a comment in an extended regex that started immediately after a meta-item
2338    extended to the end of string, PCRE compiled incorrect data. This could lead to
2339    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2340    
2341    2. Moved to autoconf 2.53 and libtool 1.4.2.
2342    
2343    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2344    the special perltest8 script is no longer needed - all the tests can be run
2345    from a single perltest script.
2346    
2347    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2348    by \s. It has now been removed in PCRE. This means it isn't recognized as
2349    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2350    class [:space:] *does* include VT, thereby creating a mess.
2351    
2352    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2353    space and tab.
2354    
2355    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2356    its new features into the main test script, reducing the number of scripts.
2357    
2358    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2359    were backward compatible, and made the (?i) apply to the whole pattern, as if
2360    /i were given. Now it behaves more logically, and applies the option setting
2361    only to what follows. PCRE has been changed to follow suit. However, if it
2362    finds options settings right at the start of the pattern, it extracts them into
2363    the global options, as before. Thus, they show up in the info data.
2364    
2365    8. Added support for the \Q...\E escape sequence. Characters in between are
2366    treated as literals. This is slightly different from Perl in that $ and @ are
2367    also handled as literals inside the quotes. In Perl, they will cause variable
2368    interpolation. Note the following examples:
2369    
2370        Pattern            PCRE matches      Perl matches
2371    
2372        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2373        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2374        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2375    
2376    For compatibility with Perl, \Q...\E sequences are recognized inside character
2377    classes as well as outside them.
2378    
2379    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2380    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2381    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2382    signed/unsigned warnings.
2383    
2384    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2385    option for pcretest, so I've replaced it by a simple function that does just
2386    that job.
2387    
2388    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2389    "pcregrep -".
2390    
2391    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2392    Java package. This provides some syntactic sugar for simple cases of what my
2393    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2394    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2395    item, you can use this simplified notation. Note that only makes sense with
2396    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2397    greediness, whatever the setting of the PCRE_UNGREEDY option.
2398    
2399    13. A change of greediness default within a pattern was not taking effect at
2400    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2401    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2402    was abstracted outside.
2403    
2404    14. PCRE now supports the \G assertion. It is true when the current matching
2405    position is at the start point of the match. This differs from \A when the
2406    starting offset is non-zero. Used with the /g option of pcretest (or similar
2407    code), it works in the same way as it does for Perl's /g option. If all
2408    alternatives of a regex begin with \G, the expression is anchored to the start
2409    match position, and the "anchored" flag is set in the compiled expression.
2410    
2411    15. Some bugs concerning the handling of certain option changes within patterns
2412    have been fixed. These applied to options other than (?ims). For example,
2413    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2414    been the other way round. Some of this was related to change 7 above.
2415    
2416    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2417    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2418    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2419    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2420    
2421    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2422    mode. Unlike ".", it always matches newline, whatever the setting of
2423    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2424    assertions. Perl allows it, but it doesn't (in general) work because it can't
2425    calculate the length of the lookbehind. At least, that's the case for Perl
2426    5.8.0 - I've been told they are going to document that it doesn't work in
2427    future.
2428    
2429    18. Added an error diagnosis for escapes that PCRE does not support: these are
2430    \L, \l, \N, \P, \p, \U, \u, and \X.
2431    
2432    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2433    reading past the end of the pattern in cases such as /[abcd/.
2434    
2435    20. PCRE was getting more memory than necessary for patterns with classes that
2436    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2437    
2438    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2439    compiling PCRE for use with Virtual Pascal.
2440    
2441    22. Small fix to the Makefile to make it work properly if the build is done
2442    outside the source tree.
2443    
2444    23. Added a new extension: a condition to go with recursion. If a conditional
2445    subpattern starts with (?(R) the "true" branch is used if recursion has
2446    happened, whereas the "false" branch is used only at the top level.
2447    
2448    24. When there was a very long string of literal characters (over 255 bytes
2449    without UTF support, over 250 bytes with UTF support), the computation of how
2450    much memory was required could be incorrect, leading to segfaults or other
2451    strange effects.
2452    
2453    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2454    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2455    there was a subsequent back reference to those brackets. This meant that, for
2456    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2457    possible to check for precisely this case. All we can do is abandon the
2458    optimization if .* occurs inside capturing brackets when there are any back
2459    references whatsoever. (See below for a better fix that came later.)
2460    
2461    26. The handling of the optimization for finding the first character of a
2462    non-anchored pattern, and for finding a character that is required later in the
2463    match were failing in some cases. This didn't break the matching; it just
2464    failed to optimize when it could. The way this is done has been re-implemented.
2465    
2466    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2467    
2468    28. Added a new feature that provides some of the functionality that Perl
2469    provides with (?{...}). The facility is termed a "callout". The way it is done
2470    in PCRE is for the caller to provide an optional function, by setting
2471    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2472    global variable. By default it is unset, which disables all calling out. To get
2473    the function called, the regex must include (?C) at appropriate points. This
2474    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2475    This provides a means of identifying different callout points. When PCRE
2476    reaches such a point in the regex, if pcre_callout has been set, the external
2477    function is called. It is provided with data in a structure called
2478    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2479    matching continues; if it returns a non-zero value, the match at the current
2480    point fails. However, backtracking will occur if possible. [This was changed
2481    later and other features added - see item 49 below.]
2482    
2483    29. pcretest is upgraded to test the callout functionality. It provides a
2484    callout function that displays information. By default, it shows the start of
2485    the match and the current position in the text. There are some new data escapes
2486    to vary what happens:
2487    
2488        \C+         in addition, show current contents of captured substrings
2489        \C-         do not supply a callout function
2490        \C!n        return 1 when callout number n is reached
2491        \C!n!m      return 1 when callout number n is reached for the mth time
2492    
2493    30. If pcregrep was called with the -l option and just a single file name, it
2494    output "<stdin>" if a match was found, instead of the file name.
2495    
2496    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2497    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2498    pcre_exec(). This saves a malloc/free per call. The default value of
2499    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2500    when configuring.
2501    
2502    32. The default maximum size of a compiled pattern is 64K. There have been a
2503    few cases of people hitting this limit. The code now uses macros to handle the
2504    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2505    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2506    configuring. Tests 2 and 5 work only with 2-byte links because they output
2507    debugging information about compiled patterns.
2508    
2509    33. Internal code re-arrangements:
2510    
2511    (a) Moved the debugging function for printing out a compiled regex into
2512        its own source file (printint.c) and used #include to pull it into
2513        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2514        separate copies.
2515    
2516    (b) Defined the list of op-code names for debugging as a macro in
2517        internal.h so that it is next to the definition of the opcodes.
2518    
2519    (c) Defined a table of op-code lengths for simpler skipping along compiled
2520        code. This is again a macro in internal.h so that it is next to the
2521        definition of the opcodes.
2522    
2523    34. Added support for recursive calls to individual subpatterns, along the
2524    lines of Robin Houston's patch (but implemented somewhat differently).
2525    
2526    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2527    allow it to read and process whole directories in Win32. This code was
2528    contributed by Lionel Fourquaux; it has not been tested by me.
2529    
2530    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2531    used to name a group. Names consist of alphanumerics and underscores, and must
2532    be unique. Back references use the syntax (?P=name) and recursive calls use
2533    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2534    numbers. The function pcre_fullinfo() can be used after compilation to extract
2535    a name/number map. There are three relevant calls:
2536    
2537      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2538      PCRE_INFO_NAMECOUNT            yields the number of entries
2539      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2540    
2541    The map is a vector of fixed-size entries. The size of each entry depends on
2542    the length of the longest name used. The first two bytes of each entry are the
2543    group number, most significant byte first. There follows the corresponding
2544    name, zero terminated. The names are in alphabetical order.
2545    
2546    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2547    case instead of 255. Making it the same both with and without UTF-8 support
2548    means that the same test output works with both.
2549    
2550    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2551    calling malloc() with a zero argument.
2552    
2553    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2554    optimization. I've improved things by keeping a bitmap of backreferences with
2555    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2556    fact referenced, the optimization can be applied. It is unlikely that a
2557    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2558    the match to follow \n) will appear inside brackets with a number greater than
2559    31, but if it does, any back reference > 31 suppresses the optimization.
2560    
2561    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2562    of disabling numbered capturing parentheses. Any opening parenthesis that is
2563    not followed by ? behaves as if it were followed by ?: but named parentheses
2564    can still be used for capturing (and they will acquire numbers in the usual
2565    way).
2566    
2567    41. Redesigned the return codes from the match() function into yes/no/error so
2568    that errors can be passed back from deep inside the nested calls. A malloc
2569    failure while inside a recursive subpattern call now causes the
2570    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2571    
2572    42. It is now possible to set a limit on the number of times the match()
2573    function is called in a call to pcre_exec(). This facility makes it possible to
2574    limit the amount of recursion and backtracking, though not in a directly
2575    obvious way, because the match() function is used in a number of different
2576    circumstances. The count starts from zero for each position in the subject
2577    string (for non-anchored patterns). The default limit is, for compatibility, a
2578    large number, namely 10 000 000. You can change this in two ways:
2579    
2580    (a) When configuring PCRE before making, you can use --with-match-limit=n
2581        to set a default value for the compiled library.
2582    
2583    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2584        a different value is set. See 45 below.
2585    
2586    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2587    
2588    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2589    of things that can be changed at compile time. The first argument specifies
2590    what is wanted and the second points to where the information is to be placed.
2591    The current list of available information is:
2592    
2593      PCRE_CONFIG_UTF8
2594    
2595    The output is an integer that is set to one if UTF-8 support is available;
2596    otherwise it is set to zero.
2597    
2598      PCRE_CONFIG_NEWLINE
2599    
2600    The output is an integer that it set to the value of the code that is used for
2601    newline. It is either LF (10) or CR (13).
2602    
2603      PCRE_CONFIG_LINK_SIZE
2604    
2605    The output is an integer that contains the number of bytes used for internal
2606    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2607    
2608      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2609    
2610    The output is an integer that contains the threshold above which the POSIX
2611    interface uses malloc() for output vectors. See item 31 above.
2612    
2613      PCRE_CONFIG_MATCH_LIMIT
2614    
2615    The output is an unsigned integer that contains the default limit of the number
2616    of match() calls in a pcre_exec() execution. See 42 above.
2617    
2618    44. pcretest has been upgraded by the addition of the -C option. This causes it
2619    to extract all the available output from the new pcre_config() function, and to
2620    output it. The program then exits immediately.
2621    
2622    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2623    order to support additional features. One way would have been to define
2624    pcre_exec2() (for example) with extra arguments, but this would not have been
2625    extensible, and would also have required all calls to the original function to
2626    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2627    is used for passing in "extra" data from pcre_study().
2628    
2629    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2630    contains the following fields:
2631    
2632      flags         a bitmap indicating which of the following fields are set
2633      study_data    opaque data from pcre_study()
2634      match_limit   a way of specifying a limit on match() calls for a specific
2635                      call to pcre_exec()
2636      callout_data  data for callouts (see 49 below)
2637    
2638    The flag bits are also defined in pcre.h, and are
2639    
2640      PCRE_EXTRA_STUDY_DATA
2641      PCRE_EXTRA_MATCH_LIMIT
2642      PCRE_EXTRA_CALLOUT_DATA
2643    
2644    The pcre_study() function now returns one of these new pcre_extra blocks, with
2645    the actual study data pointed to by the study_data field, and the
2646    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2647    before. That is, this change is entirely upwards-compatible and requires no
2648    change to existing code.
2649    
2650    If you want to pass in additional data to pcre_exec(), you can either place it
2651    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2652    block.
2653    
2654    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2655    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2656    times with different match limits, until it finds the minimum value needed for
2657    pcre_exec() to complete. The value is then output. This can be instructive; for
2658    most simple matches the number is quite small, but for pathological cases it
2659    gets very large very quickly.
2660    
2661    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2662    returns the size of the data block pointed to by the study_data field in a
2663    pcre_extra block, that is, the value that was passed as the argument to
2664    pcre_malloc() when PCRE was getting memory in which to place the information
2665    created by pcre_study(). The fourth argument should point to a size_t variable.
2666    pcretest has been extended so that this information is shown after a successful
2667    pcre_study() call when information about the compiled regex is being displayed.
2668    
2669    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2670    because what follows is always an absolute path. (Later: it turns out that this
2671    is more than cosmetic for MinGW, because it doesn't like empty path
2672    components.)
2673    
2674    49. Some changes have been made to the callout feature (see 28 above):
2675    
2676    (i)  A callout function now has three choices for what it returns:
2677    
2678           0  =>  success, carry on matching
2679         > 0  =>  failure at this point, but backtrack if possible
2680         < 0  =>  serious error, return this value from pcre_exec()
2681    
2682         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2683         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2684         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2685         use by callout functions. It will never be used by PCRE itself.
2686    
2687    (ii) The pcre_extra structure (see 45 above) has a void * field called
2688         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2689         pcre_callout_block structure has a field of the same name. The contents of
2690         the field passed in the pcre_extra structure are passed to the callout
2691         function in the corresponding field in the callout block. This makes it
2692         easier to use the same callout-containing regex from multiple threads. For
2693         testing, the pcretest program has a new data escape
2694    
2695           \C*n        pass the number n (may be negative) as callout_data
2696    
2697         If the callout function in pcretest receives a non-zero value as
2698         callout_data, it returns that value.
2699    
2700    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2701    there were some redundant $(CFLAGS) in commands that are now specified as
2702    $(LINK), which already includes $(CFLAGS).
2703    
2704    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2705    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2706    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2707    one-byte characters throughout. Note that case-insensitive matching applies
2708    only to characters whose values are less than 256. PCRE doesn't support the
2709    notion of cases for higher-valued characters.
2710    
2711    (i)   A character class whose characters are all within 0-255 is handled as
2712          a bit map, and the map is inverted for negative classes. Previously, a
2713          character > 255 always failed to match such a class; however it should
2714          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2715    
2716    (ii)  A negated character class with a single character < 255 is coded as
2717          "not this character" (OP_NOT). This wasn't working properly when the test
2718          character was multibyte, either singly or repeated.
2719    
2720    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2721          mode, for example: \x{100}{2,3}.
2722    
2723    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2724          singly or repeated) now correctly test multibyte characters. However,
2725          PCRE doesn't recognize any characters with values greater than 255 as
2726          digits, spaces, or word characters. Such characters always match \D, \S,
2727          and \W, and never match \d, \s, or \w.
2728    
2729    (v)   Classes may now contain characters and character ranges with values
2730          greater than 255. For example: [ab\x{100}-\x{400}].
2731    
2732    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2733          PCRE in UTF-8 mode.
2734    
2735    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2736    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2737    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2738    value.)
2739    
2740    53. The single man page has become too large. I have therefore split it up into
2741    a number of separate man pages. These also give rise to individual HTML pages;
2742    these are now put in a separate directory, and there is an index.html page that
2743    lists them all. Some hyperlinking between the pages has been installed.
2744    
2745    54. Added convenience functions for handling named capturing parentheses.
2746    
2747    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2748    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2749    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2750    are faulted.
2751    
2752    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2753    calling configure. These values are used when compiling the dftables.c program
2754    which is run to generate the source of the default character tables. They
2755    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2756    you will need to set these values.
2757    
2758    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2759    
2760    
2761    Version 3.9 02-Jan-02
2762    ---------------------
2763    
2764    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2765    
2766    2. If --disable-static was given, the building process failed when trying to
2767    build pcretest and pcregrep. (For some reason it was using libtool to compile
2768    them, which is not right, as they aren't part of the library.)
2769    
2770    
2771    Version 3.8 18-Dec-01
2772    ---------------------
2773    
2774    1. The experimental UTF-8 code was completely screwed up. It was packing the
2775    bytes in the wrong order. How dumb can you get?
2776    
2777    
2778    Version 3.7 29-Oct-01
2779    ---------------------
2780    
2781    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2782    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2783    this didn't happen under Solaris 8, where I normally test things.
2784    
2785    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2786    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2787    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2788    this fix an hour or so after the initial 3.7 release.)
2789    
2790    
2791    Version 3.6 23-Oct-01
2792    ---------------------
2793    
2794    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2795    offsets passed as NULL with zero offset count.
2796    
2797    2. The config.guess and config.sub files had not been updated when I moved to
2798    the latest autoconf.
2799    
2800    
2801    Version 3.5 15-Aug-01
2802    ---------------------
2803    
2804    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2805    had been forgotten.
2806    
2807    2. By using declared but undefined structures, we can avoid using "void"
2808    definitions in pcre.h while keeping the internal definitions of the structures
2809    private.
2810    
2811    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2812    user point of view, this means that both static and shared libraries are built
2813    by default, but this can be individually controlled. More of the work of
2814    handling this static/shared cases is now inside libtool instead of PCRE's make
2815    file.
2816    
2817    4. The pcretest utility is now installed along with pcregrep because it is
2818    useful for users (to test regexs) and by doing this, it automatically gets
2819    relinked by libtool. The documentation has been turned into a man page, so
2820    there are now .1, .txt, and .html versions in /doc.
2821    
2822    5. Upgrades to pcregrep:
2823       (i)   Added long-form option names like gnu grep.
2824       (ii)  Added --help to list all options with an explanatory phrase.
2825       (iii) Added -r, --recursive to recurse into sub-directories.
2826       (iv)  Added -f, --file to read patterns from a file.
2827    
2828    6. pcre_exec() was referring to its "code" argument before testing that
2829    argument for NULL (and giving an error if it was NULL).
2830    
2831    7. Upgraded Makefile.in to allow for compiling in a different directory from
2832    the source directory.
2833    
2834    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2835    options bits, the pointer it was passed was to an int instead of to an unsigned
2836    long int. This mattered only on 64-bit systems.
2837    
2838    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2839    generated) instead of pcre.in, which it its source. Also made the same change
2840    in several of the .c files.
2841    
2842    10. A new release of gcc defines printf() as a macro, which broke pcretest
2843    because it had an ifdef in the middle of a string argument for printf(). Fixed
2844    by using separate calls to printf().
2845    
2846    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2847    script, to force use of CR or LF instead of \n in the source. On non-Unix
2848    systems, the value can be set in config.h.
2849    
2850    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2851    absolute limit. Changed the text of the error message to make this clear, and
2852    likewise updated the man page.
2853    
2854    13. The limit of 99 on the number of capturing subpatterns has been removed.
2855    The new limit is 65535, which I hope will not be a "real" limit.
2856    
2857    
2858    Version 3.4 22-Aug-00
2859    ---------------------
2860    
2861    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2862    
2863    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2864    
2865    
2866    Version 3.3 01-Aug-00
2867    ---------------------
2868    
2869    1. If an octal character was given, but the value was greater than \377, it
2870    was not getting masked to the least significant bits, as documented. This could
2871    lead to crashes in some systems.
2872    
2873    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2874    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2875    
2876    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2877    These just pass their arguments on to (pcre_free)(), but they are provided
2878    because some uses of PCRE bind it to non-C systems that can call its functions,
2879    but cannot call free() or pcre_free() directly.
2880    
2881    4. Add "make test" as a synonym for "make check". Corrected some comments in
2882    the Makefile.
2883    
2884    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2885    Makefile.
2886    
2887    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2888    command called pgrep for grepping around the active processes.
2889    
2890    7. Added the beginnings of support for UTF-8 character strings.
2891    
2892    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2893    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2894    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2895    out for the ar command.)
2896    
2897    
2898    Version 3.2 12-May-00
2899    ---------------------
2900    
2901    This is purely a bug fixing release.
2902    
2903    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2904    of ZA. This was just one example of several cases that could provoke this bug,
2905    which was introduced by change 9 of version 2.00. The code for breaking
2906    infinite loops after an iteration that matches an empty string was't working
2907    correctly.
2908    
2909    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2910    when matched against abbab (for example). After matching an empty string, it
2911    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2912    caused it to match further down the string than it should.
2913    
2914    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2915    was there because it doesn't seem to be needed, and it causes trouble on some
2916    systems, as it is not a Standard C header. It has been removed.
2917    
2918    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2919    were reported on the Macintosh. The changes were from
2920    
2921      while ((c = *(++ptr)) != 0 && c != '\n');
2922    to
2923      while ((c = *(++ptr)) != 0 && c != '\n') ;
2924    
2925    Totally extraordinary, but if that's what it takes...
2926    
2927    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2928    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2929    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2930    assumes the way PCRE uses memmove() (always moving upwards).
2931    
2932    6. PCRE is being used in one environment where strchr() is not available. There
2933    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2934    faster code anyway.
2935    
2936    
2937    Version 3.1 09-Feb-00
2938    ---------------------
2939    
2940    The only change in this release is the fixing of some bugs in Makefile.in for
2941    the "install" target:
2942    
2943    (1) It was failing to install pcreposix.h.
2944    
2945    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2946    
2947    
2948    Version 3.0 01-Feb-00
2949    ---------------------
2950    
2951    1. Add support for the /+ modifier to perltest (to output $` like it does in
2952    pcretest).
2953    
2954    2. Add support for the /g modifier to perltest.
2955    
2956    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2957    matches null strings.
2958    
2959    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2960    pattern. Perl treats empty patterns specially - it reuses the most recent
2961    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2962    effect.
2963    
2964    5. The POSIX interface was broken in that it was just handing over the POSIX
2965    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2966    required a bigger vector, with some working space on the end. This means that
2967    the POSIX wrapper now has to get and free some memory, and copy the results.
2968    
2969    6. Added some simple autoconf support, placing the test data and the
2970    documentation in separate directories, re-organizing some of the
2971    information files, and making it build pcre-config (a GNU standard). Also added
2972    libtool support for building PCRE as a shared library, which is now the
2973    default.
2974    
2975    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2976    09 are not valid octal constants. Single digits will be used for minor values
2977    less than 10.
2978    
2979    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2980    existing programs that set these in the POSIX interface can use PCRE without
2981    modification.
2982    
2983    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2984    return all that pcre_info() returns, plus additional data. The pcre_info()
2985    function is retained for compatibility, but is considered to be obsolete.
2986    
2987    10. Added experimental recursion feature (?R) to handle one common case that
2988    Perl 5.6 will be able to do with (?p{...}).
2989    
2990    11. Added support for POSIX character classes like [:alpha:], which Perl is
2991    adopting.
2992    
2993    
2994  Version 2.08 31-Aug-99  Version 2.08 31-Aug-99
2995  ----------------------  ----------------------

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