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8        was out-of-date, and there was no check on the pcre_compile() error code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

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