/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 7 by nigel, Sat Feb 24 21:38:09 2007 UTC revision 420 by ph10, Wed Aug 12 17:32:27 2009 UTC
# Line 1  Line 1 
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8        was out-of-date, and there was no check on the pcre_compile() error code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    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
13        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14        in a Windows environment.
15    
16    3.  The pcregrep --count option prints the count for each file even when it is
17        zero, as does GNU grep. However, pcregrep was also printing all files when
18        --files-with-matches was added. Now, when both options are given, it prints
19        counts only for those files that have at least one match. (GNU grep just
20        prints the file name in this circumstance, but including the count seems
21        more useful - otherwise, why use --count?) Also ensured that the
22        combination -clh just lists non-zero counts, with no names.
23    
24    
25    Version 7.9 11-Apr-09
26    ---------------------
27    
28    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
29        (pcretest), all targets were linked against these libraries. This included
30        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
31        libraries. This caused unwanted dependencies to be created. This problem
32        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
33        pcretest is linked with readline.
34    
35    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
36        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
37        moved outside it again, because FALSE and TRUE are already defined in AIX,
38        but BOOL is not.
39    
40    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
41        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
42    
43    4.  The pcregrep documentation said spaces were inserted as well as colons (or
44        hyphens) following file names and line numbers when outputting matching
45        lines. This is not true; no spaces are inserted. I have also clarified the
46        wording for the --colour (or --color) option.
47    
48    5.  In pcregrep, when --colour was used with -o, the list of matching strings
49        was not coloured; this is different to GNU grep, so I have changed it to be
50        the same.
51    
52    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
53        each matching line was coloured. Now it goes on to look for further matches
54        of any of the test patterns, which is the same behaviour as GNU grep.
55    
56    7.  A pattern that could match an empty string could cause pcregrep to loop; it
57        doesn't make sense to accept an empty string match in pcregrep, so I have
58        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
59        seems to be how GNU grep behaves.
60    
61    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
62        start or after a newline", because the conditional assertion was not being
63        correctly handled. The rule now is that both the assertion and what follows
64        in the first alternative must satisfy the test.
65    
66    9.  If auto-callout was enabled in a pattern with a conditional group whose
67        condition was an assertion, PCRE could crash during matching, both with
68        pcre_exec() and pcre_dfa_exec().
69    
70    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
71        used for matching.
72    
73    11. Unicode property support in character classes was not working for
74        characters (bytes) greater than 127 when not in UTF-8 mode.
75    
76    12. Added the -M command line option to pcretest.
77    
78    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
79    
80    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
81    
82    16. Added comments and documentation about mis-use of no_arg in the C++
83        wrapper.
84    
85    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
86        from Martin Jerabek that uses macro names for all relevant character and
87        string constants.
88    
89    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
90        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
91        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
92        these, but not everybody uses configure.
93    
94    19. A conditional group that had only one branch was not being correctly
95        recognized as an item that could match an empty string. This meant that an
96        enclosing group might also not be so recognized, causing infinite looping
97        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
98        with the subject "ab", where knowledge that the repeated group can match
99        nothing is needed in order to break the loop.
100    
101    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
102        exec(), but without supplying a callout function, matching went wrong.
103    
104    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
105        leak if the size of the offset vector was greater than 30. When the vector
106        is smaller, the saved offsets during recursion go onto a local stack
107        vector, but for larger vectors malloc() is used. It was failing to free
108        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
109        error, in fact).
110    
111    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
112        heapframe that is used only when UTF-8 support is enabled. This caused no
113        problem, but was untidy.
114    
115    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
116        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
117        included within another project.
118    
119    24. Steven Van Ingelgem's patches to add more options to the CMake support,
120        slightly modified by me:
121    
122          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
123              not building pcregrep.
124    
125          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
126              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
127    
128    25. Forward references, both numeric and by name, in patterns that made use of
129        duplicate group numbers, could behave incorrectly or give incorrect errors,
130        because when scanning forward to find the reference group, PCRE was not
131        taking into account the duplicate group numbers. A pattern such as
132        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
133    
134    26. Changed a few more instances of "const unsigned char *" to USPTR, making
135        the feature of a custom pointer more persuasive (as requested by a user).
136    
137    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
138        pcretest.c, inside #ifndefs, because it seems they are sometimes already
139        pre-defined.
140    
141    28. Added support for (*UTF8) at the start of a pattern.
142    
143    29. Arrange for flags added by the "release type" setting in CMake to be shown
144        in the configuration summary.
145    
146    
147    Version 7.8 05-Sep-08
148    ---------------------
149    
150    1.  Replaced UCP searching code with optimized version as implemented for Ad
151        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
152        stage table and inline lookup instead of a function, giving speed ups of 2
153        to 5 times on some simple patterns that I tested. Permission was given to
154        distribute the MultiStage2.py script that generates the tables (it's not in
155        the tarball, but is in the Subversion repository).
156    
157    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
158        scripts.
159    
160    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
161        a group with a zero qualifier. The result of the study could be incorrect,
162        or the function might crash, depending on the pattern.
163    
164    4.  Caseless matching was not working for non-ASCII characters in back
165        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
166        It now works when Unicode Property Support is available.
167    
168    5.  In pcretest, an escape such as \x{de} in the data was always generating
169        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
170        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
171        truncation.
172    
173    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
174    
175    7.  Added two (int) casts to pcregrep when printing the difference of two
176        pointers, in case they are 64-bit values.
177    
178    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
179        test 2 if it fails.
180    
181    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
182        and a #define of that name to empty if it is not externally set. This is to
183        allow users of MSVC to set it if necessary.
184    
185    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
186        the convenience functions in the pcre_get.c source file.
187    
188    11. An option change at the start of a pattern that had top-level alternatives
189        could cause overwriting and/or a crash. This command provoked a crash in
190        some environments:
191    
192          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
193    
194        This potential security problem was recorded as CVE-2008-2371.
195    
196    12. For a pattern where the match had to start at the beginning or immediately
197        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
198        pcre_dfa_exec() could read past the end of the passed subject if there was
199        no match. To help with detecting such bugs (e.g. with valgrind), I modified
200        pcretest so that it places the subject at the end of its malloc-ed buffer.
201    
202    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
203        exec() might read past the end of the data buffer in UTF-8 mode.
204    
205    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
206        the data contained the byte 0x85 as part of a UTF-8 character within its
207        first line. This applied both to normal and DFA matching.
208    
209    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
210        /^[^d]*?$/8 failed to match "abc".
211    
212    16. Added a missing copyright notice to pcrecpp_internal.h.
213    
214    17. Make it more clear in the documentation that values returned from
215        pcre_exec() in ovector are byte offsets, not character counts.
216    
217    18. Tidied a few places to stop certain compilers from issuing warnings.
218    
219    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
220        supplied by Stefan Weber. I made a further small update for 7.8 because
221        there is a change of source arrangements: the pcre_searchfuncs.c module is
222        replaced by pcre_ucd.c.
223    
224    
225    Version 7.7 07-May-08
226    ---------------------
227    
228    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
229        a string to a long long, pretend we don't even have a long long." This is
230        done by checking for the strtoq, strtoll, and _strtoi64 functions.
231    
232    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
233        pre-7.6 versions, which defined a global no_arg variable instead of putting
234        it in the RE class. (See also #8 below.)
235    
236    3.  Remove a line of dead code, identified by coverity and reported by Nuno
237        Lopes.
238    
239    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
240    
241        (1) The include/exclude patterns were being applied to the whole pathnames
242            of files, instead of just to the final components.
243    
244        (2) If there was more than one level of directory, the subdirectories were
245            skipped unless they satisfied the include/exclude conditions. This is
246            inconsistent with GNU grep (and could even be seen as contrary to the
247            pcregrep specification - which I improved to make it absolutely clear).
248            The action now is always to scan all levels of directory, and just
249            apply the include/exclude patterns to regular files.
250    
251    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
252        --exclude_dir in the tests to avoid scanning .svn directories.
253    
254    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
255        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
256        doesn't support NULs in patterns.
257    
258    7.  Added some missing "const"s to declarations of static tables in
259        pcre_compile.c and pcre_dfa_exec.c.
260    
261    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
262        caused by fix #2  above. (Subsequently also a second patch to fix the
263        first patch. And a third patch - this was a messy problem.)
264    
265    9.  Applied Craig's patch to remove the use of push_back().
266    
267    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
268        matching function regexec().
269    
270    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
271        which, however, unlike Perl's \g{...}, are subroutine calls, not back
272        references. PCRE supports relative numbers with this syntax (I don't think
273        Oniguruma does).
274    
275    12. Previously, a group with a zero repeat such as (...){0} was completely
276        omitted from the compiled regex. However, this means that if the group
277        was called as a subroutine from elsewhere in the pattern, things went wrong
278        (an internal error was given). Such groups are now left in the compiled
279        pattern, with a new opcode that causes them to be skipped at execution
280        time.
281    
282    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
283        to the way PCRE behaves:
284    
285        (a) A lone ] character is dis-allowed (Perl treats it as data).
286    
287        (b) A back reference to an unmatched subpattern matches an empty string
288            (Perl fails the current match path).
289    
290        (c) A data ] in a character class must be notated as \] because if the
291            first data character in a class is ], it defines an empty class. (In
292            Perl it is not possible to have an empty class.) The empty class []
293            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
294            The negative empty class [^] matches any one character, independently
295            of the DOTALL setting.
296    
297    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
298        non-existent subpattern following a character class starting with ']' and
299        containing () gave an internal compiling error instead of "reference to
300        non-existent subpattern". Fortunately, when the pattern did exist, the
301        compiled code was correct. (When scanning forwards to check for the
302        existencd of the subpattern, it was treating the data ']' as terminating
303        the class, so got the count wrong. When actually compiling, the reference
304        was subsequently set up correctly.)
305    
306    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
307        it was being rejected as not supported by pcre_dfa_exec(), even though
308        other assertions are supported. I have made pcre_dfa_exec() support
309        (*FAIL).
310    
311    16. The implementation of 13c above involved the invention of a new opcode,
312        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
313        cannot be changed at match time, I realized I could make a small
314        improvement to matching performance by compiling OP_ALLANY instead of
315        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
316        on the OP_ANY path.
317    
318    17. Compiling pcretest on Windows with readline support failed without the
319        following two fixes: (1) Make the unistd.h include conditional on
320        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
321    
322    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
323        ncurses library to be included for pcretest when ReadLine support is
324        requested, but also to allow for it to be overridden. This patch came from
325        Daniel Bergström.
326    
327    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
328        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
329        any errors with the current Unicode tables. Thanks to Peter Kankowski for
330        spotting this.
331    
332    
333    Version 7.6 28-Jan-08
334    ---------------------
335    
336    1.  A character class containing a very large number of characters with
337        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
338        overflow.
339    
340    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
341        HAVE_LONG_LONG is not defined.
342    
343    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
344        bring them up to date and include new features. This patch includes:
345    
346        - Fixed PH's badly added libz and libbz2 support.
347        - Fixed a problem with static linking.
348        - Added pcredemo. [But later removed - see 7 below.]
349        - Fixed dftables problem and added an option.
350        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
351            HAVE_LONG_LONG.
352        - Added readline support for pcretest.
353        - Added an listing of the option settings after cmake has run.
354    
355    4.  A user submitted a patch to Makefile that makes it easy to create
356        "pcre.dll" under mingw when using Configure/Make. I added stuff to
357        Makefile.am that cause it to include this special target, without
358        affecting anything else. Note that the same mingw target plus all
359        the other distribution libraries and programs are now supported
360        when configuring with CMake (see 6 below) instead of with
361        Configure/Make.
362    
363    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
364        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
365        exported in the Windows port". It has not yet been confirmed that the patch
366        solves the problem, but it does no harm.
367    
368    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
369        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
370        with CMake, and also correct the comment about stack recursion.
371    
372    7.  Remove the automatic building of pcredemo from the ./configure system and
373        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
374        of a program that users should build themselves after PCRE is installed, so
375        building it automatically is not really right. What is more, it gave
376        trouble in some build environments.
377    
378    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
379    
380    
381    Version 7.5 10-Jan-08
382    ---------------------
383    
384    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
385        values in parens when parsing an RE using the C++ wrapper."
386    
387    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
388        Characters greater than 255 were excluded from the class instead of being
389        included.
390    
391    3.  The same bug as (2) above applied to negated POSIX classes such as
392        [:^space:].
393    
394    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
395        defined or documented. It seems to have been a typo for PCRE_STATIC, so
396        I have changed it.
397    
398    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
399        first named subpattern) and a construct such as (?&a) would reference the
400        first named subpattern whose name started with "a" (in other words, the
401        length check was missing). Both these problems are fixed. "Subpattern name
402        expected" is now given for (?&) (a zero-length name), and this patch also
403        makes it give the same error for \k'' (previously it complained that that
404        was a reference to a non-existent subpattern).
405    
406    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
407        this is right because (?- can be followed by option settings as well as by
408        digits. I have, however, made the messages clearer.
409    
410    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
411        than the number used in the conditional) now cause a compile-time error.
412        This is actually not compatible with Perl, which accepts such patterns, but
413        treats the conditional as always being FALSE (as PCRE used to), but it
414        seems to me that giving a diagnostic is better.
415    
416    8.  Change "alphameric" to the more common word "alphanumeric" in comments
417        and messages.
418    
419    9.  Fix two occurrences of "backslash" in comments that should have been
420        "backspace".
421    
422    10. Remove two redundant lines of code that can never be obeyed (their function
423        was moved elsewhere).
424    
425    11. The program that makes PCRE's Unicode character property table had a bug
426        which caused it to generate incorrect table entries for sequences of
427        characters that have the same character type, but are in different scripts.
428        It amalgamated them into a single range, with the script of the first of
429        them. In other words, some characters were in the wrong script. There were
430        thirteen such cases, affecting characters in the following ranges:
431    
432          U+002b0 - U+002c1
433          U+0060c - U+0060d
434          U+0061e - U+00612
435          U+0064b - U+0065e
436          U+0074d - U+0076d
437          U+01800 - U+01805
438          U+01d00 - U+01d77
439          U+01d9b - U+01dbf
440          U+0200b - U+0200f
441          U+030fc - U+030fe
442          U+03260 - U+0327f
443          U+0fb46 - U+0fbb1
444          U+10450 - U+1049d
445    
446    12. The -o option (show only the matching part of a line) for pcregrep was not
447        compatible with GNU grep in that, if there was more than one match in a
448        line, it showed only the first of them. It now behaves in the same way as
449        GNU grep.
450    
451    13. If the -o and -v options were combined for pcregrep, it printed a blank
452        line for every non-matching line. GNU grep prints nothing, and pcregrep now
453        does the same. The return code can be used to tell if there were any
454        non-matching lines.
455    
456    14. Added --file-offsets and --line-offsets to pcregrep.
457    
458    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
459        infinitely looping recursion. The bug was that positive lookaheads were not
460        being skipped when checking for a possible empty match (negative lookaheads
461        and both kinds of lookbehind were skipped).
462    
463    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
464        inclusion of <windows.h> to before rather than after the definition of
465        INVALID_FILE_ATTRIBUTES (patch from David Byron).
466    
467    17. Specifying a possessive quantifier with a specific limit for a Unicode
468        character property caused pcre_compile() to compile bad code, which led at
469        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
470        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
471        caused the error; without that there was no problem.
472    
473    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
474    
475    19. Added --enable-pcretest-libreadline.
476    
477    20. In pcrecpp.cc, the variable 'count' was incremented twice in
478        RE::GlobalReplace(). As a result, the number of replacements returned was
479        double what it should be. I removed one of the increments, but Craig sent a
480        later patch that removed the other one (the right fix) and added unit tests
481        that check the return values (which was not done before).
482    
483    21. Several CMake things:
484    
485        (1) Arranged that, when cmake is used on Unix, the libraries end up with
486            the names libpcre and libpcreposix, not just pcre and pcreposix.
487    
488        (2) The above change means that pcretest and pcregrep are now correctly
489            linked with the newly-built libraries, not previously installed ones.
490    
491        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
492    
493    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
494        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
495        UTF-8 newline character). The key issue is that the pattern starts .*;
496        this means that the match must be either at the beginning, or after a
497        newline. The bug was in the code for advancing after a failed match and
498        checking that the new position followed a newline. It was not taking
499        account of UTF-8 characters correctly.
500    
501    23. PCRE was behaving differently from Perl in the way it recognized POSIX
502        character classes. PCRE was not treating the sequence [:...:] as a
503        character class unless the ... were all letters. Perl, however, seems to
504        allow any characters between [: and :], though of course it rejects as
505        unknown any "names" that contain non-letters, because all the known class
506        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
507        for example, whereas PCRE did not - it did not recognize a POSIX character
508        class. This seemed a bit dangerous, so the code has been changed to be
509        closer to Perl. The behaviour is not identical to Perl, because PCRE will
510        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
511        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
512        Perl does, and where it didn't before.
513    
514    24. Rewrite so as to remove the single use of %n from pcregrep because in some
515        Windows environments %n is disabled by default.
516    
517    
518    Version 7.4 21-Sep-07
519    ---------------------
520    
521    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
522        means that a class such as [\s] counted as "explicit reference to CR or
523        LF". That isn't really right - the whole point of the change was to try to
524        help when there was an actual mention of one of the two characters. So now
525        the change happens only if \r or \n (or a literal CR or LF) character is
526        encountered.
527    
528    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
529        of both had grown to the point where there were only 3 bits left.
530        Fortunately, there was spare space in the data structure, and so I have
531        moved the internal flags into a new 16-bit field to free up more option
532        bits.
533    
534    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
535        but did not set the internal JCHANGED flag - either of these is enough to
536        control the way the "get" function works - but the PCRE_INFO_JCHANGED
537        facility is supposed to tell if (?J) was ever used, so now (?J) at the
538        start sets both bits.
539    
540    4.  Added options (at build time, compile time, exec time) to change \R from
541        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
542    
543    5.  doc/pcresyntax.html was missing from the distribution.
544    
545    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
546        compatibility, even though it is no longer used.
547    
548    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
549        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
550        windows.h file is present (where different names are used). [This was
551        reversed later after testing - see 16 below.]
552    
553    8.  Changed all #include <config.h> to #include "config.h". There were also
554        some further <pcre.h> cases that I changed to "pcre.h".
555    
556    9.  When pcregrep was used with the --colour option, it missed the line ending
557        sequence off the lines that it output.
558    
559    10. It was pointed out to me that arrays of string pointers cause lots of
560        relocations when a shared library is dynamically loaded. A technique of
561        using a single long string with a table of offsets can drastically reduce
562        these. I have refactored PCRE in four places to do this. The result is
563        dramatic:
564    
565          Originally:                          290
566          After changing UCP table:            187
567          After changing error message table:   43
568          After changing table of "verbs"       36
569          After changing table of Posix names   22
570    
571        Thanks to the folks working on Gregex for glib for this insight.
572    
573    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
574        unicode-properties was also set.
575    
576    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
577    
578    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
579        checked only for CRLF.
580    
581    14. Added casts to pcretest.c to avoid compiler warnings.
582    
583    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
584    
585    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
586        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
587        entirely. This removes changes made in 7 above.
588    
589    17. The CMake files have been updated, and there is now more information about
590        building with CMake in the NON-UNIX-USE document.
591    
592    
593    Version 7.3 28-Aug-07
594    ---------------------
595    
596     1. In the rejigging of the build system that eventually resulted in 7.1, the
597        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
598        brackets there is not right, since it causes compilers to look for an
599        installed pcre.h, not the version that is in the source that is being
600        compiled (which of course may be different). I have changed it back to:
601    
602          #include "pcre.h"
603    
604        I have a vague recollection that the change was concerned with compiling in
605        different directories, but in the new build system, that is taken care of
606        by the VPATH setting the Makefile.
607    
608     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
609        when the subject happened to end in the byte 0x85 (e.g. if the last
610        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
611        characters but of course it shouldn't be taken as a newline when it is part
612        of another character. The bug was that, for an unlimited repeat of . in
613        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
614        characters when looking for a newline.
615    
616     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
617    
618     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
619        in debug output.
620    
621     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
622        long printing in the pcrecpp unittest when running under MinGW.
623    
624     6. ESC_K was left out of the EBCDIC table.
625    
626     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
627        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
628        limit also applies to "virtual nesting" when a pattern is recursive, and in
629        this case 1000 isn't so big. I have been able to remove this limit at the
630        expense of backing off one optimization in certain circumstances. Normally,
631        when pcre_exec() would call its internal match() function recursively and
632        immediately return the result unconditionally, it uses a "tail recursion"
633        feature to save stack. However, when a subpattern that can match an empty
634        string has an unlimited repetition quantifier, it no longer makes this
635        optimization. That gives it a stack frame in which to save the data for
636        checking that an empty string has been matched. Previously this was taken
637        from the 1000-entry workspace that had been reserved. So now there is no
638        explicit limit, but more stack is used.
639    
640     8. Applied Daniel's patches to solve problems with the import/export magic
641        syntax that is required for Windows, and which was going wrong for the
642        pcreposix and pcrecpp parts of the library. These were overlooked when this
643        problem was solved for the main library.
644    
645     9. There were some crude static tests to avoid integer overflow when computing
646        the size of patterns that contain repeated groups with explicit upper
647        limits. As the maximum quantifier is 65535, the maximum group length was
648        set at 30,000 so that the product of these two numbers did not overflow a
649        32-bit integer. However, it turns out that people want to use groups that
650        are longer than 30,000 bytes (though not repeat them that many times).
651        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
652        made it possible to implement the integer overflow checks in a much more
653        dynamic way, which I have now done. The artificial limitation on group
654        length has been removed - we now have only the limit on the total length of
655        the compiled pattern, which depends on the LINK_SIZE setting.
656    
657    10. Fixed a bug in the documentation for get/copy named substring when
658        duplicate names are permitted. If none of the named substrings are set, the
659        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
660        empty string.
661    
662    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
663        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
664        because the ] is interpreted as the first data character and the
665        terminating ] is not found. PCRE has been made compatible with Perl in this
666        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
667        cause memory overwriting.
668    
669    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
670        string has been matched (to stop an infinite loop). It was not recognizing
671        a conditional subpattern that could match an empty string if that
672        subpattern was within another subpattern. For example, it looped when
673        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
674        condition was not nested. This bug has been fixed.
675    
676    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
677        past the start of the subject in the presence of bytes with the top bit
678        set, for example "\x8aBCD".
679    
680    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
681        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
682    
683    14. Optimized (?!) to (*FAIL).
684    
685    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
686        This restricts code points to be within the range 0 to 0x10FFFF, excluding
687        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
688        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
689        does: it's just the validity check that is more restrictive.
690    
691    16. Inserted checks for integer overflows during escape sequence (backslash)
692        processing, and also fixed erroneous offset values for syntax errors during
693        backslash processing.
694    
695    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
696        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
697    
698    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
699        caused an overrun.
700    
701    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
702        something other than just ASCII characters) inside a group that had an
703        unlimited repeat caused a loop at compile time (while checking to see
704        whether the group could match an empty string).
705    
706    20. Debugging a pattern containing \p or \P could cause a crash. For example,
707        [\P{Any}] did so. (Error in the code for printing property names.)
708    
709    21. An orphan \E inside a character class could cause a crash.
710    
711    22. A repeated capturing bracket such as (A)? could cause a wild memory
712        reference during compilation.
713    
714    23. There are several functions in pcre_compile() that scan along a compiled
715        expression for various reasons (e.g. to see if it's fixed length for look
716        behind). There were bugs in these functions when a repeated \p or \P was
717        present in the pattern. These operators have additional parameters compared
718        with \d, etc, and these were not being taken into account when moving along
719        the compiled data. Specifically:
720    
721        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
722            length.
723    
724        (b) An item such as \pL+ within a repeated group could cause crashes or
725            loops.
726    
727        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
728            "reference to non-existent subpattern" error.
729    
730        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
731    
732    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
733        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
734    
735    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
736    
737    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
738        character were causing crashes (broken optimization).
739    
740    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
741        \p or \P) caused a compile-time loop.
742    
743    28. More problems have arisen in unanchored patterns when CRLF is a valid line
744        break. For example, the unstudied pattern [\r\n]A does not match the string
745        "\r\nA" because change 7.0/46 below moves the current point on by two
746        characters after failing to match at the start. However, the pattern \nA
747        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
748        the same is true. There doesn't seem any very clean way out of this, but
749        what I have chosen to do makes the common cases work: PCRE now takes note
750        of whether there can be an explicit match for \r or \n anywhere in the
751        pattern, and if so, 7.0/46 no longer applies. As part of this change,
752        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
753        pattern has explicit CR or LF references.
754    
755    29. Added (*CR) etc for changing newline setting at start of pattern.
756    
757    
758    Version 7.2 19-Jun-07
759    ---------------------
760    
761     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
762        which is apparently normally available under Windows.
763    
764     2. Re-jig the pcregrep tests with different newline settings in an attempt
765        to make them independent of the local environment's newline setting.
766    
767     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
768    
769     4. Some of the "internals" tests were previously cut out when the link size
770        was not 2, because the output contained actual offsets. The recent new
771        "Z" feature of pcretest means that these can be cut out, making the tests
772        usable with all link sizes.
773    
774     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
775        stack recursion. This gives a massive performance boost under BSD, but just
776        a small improvement under Linux. However, it saves one field in the frame
777        in all cases.
778    
779     6. Added more features from the forthcoming Perl 5.10:
780    
781        (a) (?-n) (where n is a string of digits) is a relative subroutine or
782            recursion call. It refers to the nth most recently opened parentheses.
783    
784        (b) (?+n) is also a relative subroutine call; it refers to the nth next
785            to be opened parentheses.
786    
787        (c) Conditions that refer to capturing parentheses can be specified
788            relatively, for example, (?(-2)... or (?(+3)...
789    
790        (d) \K resets the start of the current match so that everything before
791            is not part of it.
792    
793        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
794    
795        (f) \g{name} is another synonym - part of Perl 5.10's unification of
796            reference syntax.
797    
798        (g) (?| introduces a group in which the numbering of parentheses in each
799            alternative starts with the same number.
800    
801        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
802    
803     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
804        PCRE_INFO_JCHANGED.
805    
806     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
807        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
808        for detecting groups that can match an empty string.
809    
810     9. A pattern with a very large number of alternatives (more than several
811        hundred) was running out of internal workspace during the pre-compile
812        phase, where pcre_compile() figures out how much memory will be needed. A
813        bit of new cunning has reduced the workspace needed for groups with
814        alternatives. The 1000-alternative test pattern now uses 12 bytes of
815        workspace instead of running out of the 4096 that are available.
816    
817    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
818    
819    11. Applied patch from Google to remove an optimization that didn't quite work.
820        The report of the bug said:
821    
822          pcrecpp::RE("a*").FullMatch("aaa") matches, while
823          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
824          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
825    
826    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
827        it matched the wrong number of bytes.
828    
829    
830    Version 7.1 24-Apr-07
831    ---------------------
832    
833     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
834        that is more "standard", making use of automake and other Autotools. There
835        is some re-arrangement of the files and adjustment of comments consequent
836        on this.
837    
838     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
839        for recursive directory scanning broke on some systems because the files
840        are not scanned in any specific order and on different systems the order
841        was different. A call to "sort" has been inserted into RunGrepTest for the
842        approprate test as a short-term fix. In the longer term there may be an
843        alternative.
844    
845     3. I had an email from Eric Raymond about problems translating some of PCRE's
846        man pages to HTML (despite the fact that I distribute HTML pages, some
847        people do their own conversions for various reasons). The problems
848        concerned the use of low-level troff macros .br and .in. I have therefore
849        removed all such uses from the man pages (some were redundant, some could
850        be replaced by .nf/.fi pairs). The 132html script that I use to generate
851        HTML has been updated to handle .nf/.fi and to complain if it encounters
852        .br or .in.
853    
854     4. Updated comments in configure.ac that get placed in config.h.in and also
855        arranged for config.h to be included in the distribution, with the name
856        config.h.generic, for the benefit of those who have to compile without
857        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
858    
859     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
860        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
861        makevp.bat for the current PCRE, using the additional files
862        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
863    
864     6. A Windows user reported a minor discrepancy with test 2, which turned out
865        to be caused by a trailing space on an input line that had got lost in his
866        copy. The trailing space was an accident, so I've just removed it.
867    
868     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
869        that is needed.
870    
871     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
872        as "const" (a) because they are and (b) because it helps the PHP
873        maintainers who have recently made a script to detect big data structures
874        in the php code that should be moved to the .rodata section. I remembered
875        to update Builducptable as well, so it won't revert if ucptable.h is ever
876        re-created.
877    
878     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
879        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
880        order to be able to cut out the UTF-8 tables in the latter when UTF-8
881        support is not required. This saves 1.5-2K of code, which is important in
882        some applications.
883    
884        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
885        so as not to refer to the tables, even though these functions will never be
886        called when UTF-8 support is disabled. Otherwise there are problems with a
887        shared library.
888    
889    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
890    
891        (a) It was defining its arguments as char * instead of void *.
892    
893        (b) It was assuming that all moves were upwards in memory; this was true
894            a long time ago when I wrote it, but is no longer the case.
895    
896        The emulated memove() is provided for those environments that have neither
897        memmove() nor bcopy(). I didn't think anyone used it these days, but that
898        is clearly not the case, as these two bugs were recently reported.
899    
900    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
901        and Detrail to create the HTML documentation, the .txt form of the man
902        pages, and it removes trailing spaces from listed files. It also creates
903        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
904        case, it wraps all the #defines with #ifndefs. This script should be run
905        before "make dist".
906    
907    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
908        with Unicode property support.
909    
910        (a) For a maximizing quantifier, if the two different cases of the
911            character were of different lengths in their UTF-8 codings (there are
912            some cases like this - I found 11), and the matching function had to
913            back up over a mixture of the two cases, it incorrectly assumed they
914            were both the same length.
915    
916        (b) When PCRE was configured to use the heap rather than the stack for
917            recursion during matching, it was not correctly preserving the data for
918            the other case of a UTF-8 character when checking ahead for a match
919            while processing a minimizing repeat. If the check also involved
920            matching a wide character, but failed, corruption could cause an
921            erroneous result when trying to check for a repeat of the original
922            character.
923    
924    13. Some tidying changes to the testing mechanism:
925    
926        (a) The RunTest script now detects the internal link size and whether there
927            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
928            values substituted by "configure". (The RunGrepTest script already did
929            this for UTF-8.) The configure.ac script no longer substitutes the
930            relevant variables.
931    
932        (b) The debugging options /B and /D in pcretest show the compiled bytecode
933            with length and offset values. This means that the output is different
934            for different internal link sizes. Test 2 is skipped for link sizes
935            other than 2 because of this, bypassing the problem. Unfortunately,
936            there was also a test in test 3 (the locale tests) that used /B and
937            failed for link sizes other than 2. Rather than cut the whole test out,
938            I have added a new /Z option to pcretest that replaces the length and
939            offset values with spaces. This is now used to make test 3 independent
940            of link size. (Test 2 will be tidied up later.)
941    
942    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
943        segmentation fault instead of returning the appropriate error message.
944    
945    15. In multiline mode when the newline sequence was set to "any", the pattern
946        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
947        This doesn't seem right; it now treats the CRLF combination as the line
948        ending, and so does not match in that case. It's only a pattern such as ^$
949        that would hit this one: something like ^ABC$ would have failed after \r
950        and then tried again after \r\n.
951    
952    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
953        in an attempt to make files that differ only in their line terminators
954        compare equal. This works on Linux.
955    
956    17. Under certain error circumstances pcregrep might try to free random memory
957        as it exited. This is now fixed, thanks to valgrind.
958    
959    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
960        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
961        was because its rules for how to advance for /g after matching an empty
962        string at the end of a line did not allow for this case. They now check for
963        it specially.
964    
965    20. pcretest is supposed to handle patterns and data of any length, by
966        extending its buffers when necessary. It was getting this wrong when the
967        buffer for a data line had to be extended.
968    
969    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
970        CRLF as a newline sequence.
971    
972    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
973        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
974        I have nevertheless tidied it up.
975    
976    23. Added some casts to kill warnings from HP-UX ia64 compiler.
977    
978    24. Added a man page for pcre-config.
979    
980    
981    Version 7.0 19-Dec-06
982    ---------------------
983    
984     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
985        moving to gcc 4.1.1.
986    
987     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
988        sys/time.h, which is documented as needed for this function. It doesn't
989        seem to matter on Linux, but it showed up on some releases of OS X.
990    
991     3. It seems that there are systems where bytes whose values are greater than
992        127 match isprint() in the "C" locale. The "C" locale should be the
993        default when a C program starts up. In most systems, only ASCII printing
994        characters match isprint(). This difference caused the output from pcretest
995        to vary, making some of the tests fail. I have changed pcretest so that:
996    
997        (a) When it is outputting text in the compiled version of a pattern, bytes
998            other than 32-126 are always shown as hex escapes.
999    
1000        (b) When it is outputting text that is a matched part of a subject string,
1001            it does the same, unless a different locale has been set for the match
1002            (using the /L modifier). In this case, it uses isprint() to decide.
1003    
1004     4. Fixed a major bug that caused incorrect computation of the amount of memory
1005        required for a compiled pattern when options that changed within the
1006        pattern affected the logic of the preliminary scan that determines the
1007        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1008        that the computed length was too small. The symptoms of this bug were
1009        either the PCRE error "internal error: code overflow" from pcre_compile(),
1010        or a glibc crash with a message such as "pcretest: free(): invalid next
1011        size (fast)". Examples of patterns that provoked this bug (shown in
1012        pcretest format) are:
1013    
1014          /(?-x: )/x
1015          /(?x)(?-x: \s*#\s*)/
1016          /((?i)[\x{c0}])/8
1017          /(?i:[\x{c0}])/8
1018    
1019        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1020        is now done differently.
1021    
1022     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1023        wrapper classes; (b) implement a new function in the C++ scanner that is
1024        more efficient than the old way of doing things because it avoids levels of
1025        recursion in the regex matching; (c) add a paragraph to the documentation
1026        for the FullMatch() function.
1027    
1028     6. The escape sequence \n was being treated as whatever was defined as
1029        "newline". Not only was this contrary to the documentation, which states
1030        that \n is character 10 (hex 0A), but it also went horribly wrong when
1031        "newline" was defined as CRLF. This has been fixed.
1032    
1033     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1034        was being set to -1 for the "end of line" case (supposedly a value that no
1035        character can have). Though this value is never used (the check for end of
1036        line is "zero bytes in current character"), it caused compiler complaints.
1037        I've changed it to 0xffffffff.
1038    
1039     8. In pcre_version.c, the version string was being built by a sequence of
1040        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1041        string (as it is for production releases) called a macro with an empty
1042        argument. The C standard says the result of this is undefined. The gcc
1043        compiler treats it as an empty string (which was what was wanted) but it is
1044        reported that Visual C gives an error. The source has been hacked around to
1045        avoid this problem.
1046    
1047     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1048        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1049        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1050        of them did).
1051    
1052    10. Originally, pcretest opened its input and output without "b"; then I was
1053        told that "b" was needed in some environments, so it was added for release
1054        5.0 to both the input and output. (It makes no difference on Unix-like
1055        systems.) Later I was told that it is wrong for the input on Windows. I've
1056        now abstracted the modes into two macros, to make it easier to fiddle with
1057        them, and removed "b" from the input mode under Windows.
1058    
1059    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1060    
1061    12. Added -help and --help to pcretest as an official way of being reminded
1062        of the options.
1063    
1064    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1065        and pcrecpp.cc because they annoy compilers at high warning levels.
1066    
1067    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1068    
1069    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1070        scripts are not C programs :-) and which was not noticed because it works
1071        on Linux.
1072    
1073    16. pcretest is supposed to handle any length of pattern and data line (as one
1074        line or as a continued sequence of lines) by extending its input buffer if
1075        necessary. This feature was broken for very long pattern lines, leading to
1076        a string of junk being passed to pcre_compile() if the pattern was longer
1077        than about 50K.
1078    
1079    17. I have done a major re-factoring of the way pcre_compile() computes the
1080        amount of memory needed for a compiled pattern. Previously, there was code
1081        that made a preliminary scan of the pattern in order to do this. That was
1082        OK when PCRE was new, but as the facilities have expanded, it has become
1083        harder and harder to keep it in step with the real compile phase, and there
1084        have been a number of bugs (see for example, 4 above). I have now found a
1085        cunning way of running the real compile function in a "fake" mode that
1086        enables it to compute how much memory it would need, while actually only
1087        ever using a few hundred bytes of working memory and without too many
1088        tests of the mode. This should make future maintenance and development
1089        easier. A side effect of this work is that the limit of 200 on the nesting
1090        depth of parentheses has been removed (though this was never a serious
1091        limitation, I suspect). However, there is a downside: pcre_compile() now
1092        runs more slowly than before (30% or more, depending on the pattern). I
1093        hope this isn't a big issue. There is no effect on runtime performance.
1094    
1095    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1096        newline (only possible for the last line of a file) and it was a
1097        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1098    
1099    19. Added additional timing features to pcretest. (1) The -tm option now times
1100        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1101        separate command line item, by a number that specifies the number of
1102        repeats to use when timing. The default is 50000; this gives better
1103        precision, but takes uncomfortably long for very large patterns.
1104    
1105    20. Extended pcre_study() to be more clever in cases where a branch of a
1106        subpattern has no definite first character. For example, (a*|b*)[cd] would
1107        previously give no result from pcre_study(). Now it recognizes that the
1108        first character must be a, b, c, or d.
1109    
1110    21. There was an incorrect error "recursive call could loop indefinitely" if
1111        a subpattern (or the entire pattern) that was being tested for matching an
1112        empty string contained only one non-empty item after a nested subpattern.
1113        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1114        incorrectly, because the \d was being skipped in the check.
1115    
1116    22. The pcretest program now has a new pattern option /B and a command line
1117        option -b, which is equivalent to adding /B to every pattern. This causes
1118        it to show the compiled bytecode, without the additional information that
1119        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1120        is the same as /B/I).
1121    
1122    23. A new optimization is now able automatically to treat some sequences such
1123        as a*b as a*+b. More specifically, if something simple (such as a character
1124        or a simple class like \d) has an unlimited quantifier, and is followed by
1125        something that cannot possibly match the quantified thing, the quantifier
1126        is automatically "possessified".
1127    
1128    24. A recursive reference to a subpattern whose number was greater than 39
1129        went wrong under certain circumstances in UTF-8 mode. This bug could also
1130        have affected the operation of pcre_study().
1131    
1132    25. Realized that a little bit of performance could be had by replacing
1133        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1134    
1135    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1136    
1137    27. Possessive quantifiers such as a++ were previously implemented by turning
1138        them into atomic groups such as ($>a+). Now they have their own opcodes,
1139        which improves performance. This includes the automatically created ones
1140        from 23 above.
1141    
1142    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1143        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1144        the first matched character to be a colon. This applied both to named and
1145        numbered groups.
1146    
1147    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1148    
1149    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1150        building PCRE on Windows easier, so I have included it in the distribution.
1151    
1152    31. There is now a check in pcretest against a ridiculously large number being
1153        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1154        loop, the loop is abandoned.
1155    
1156    32. Forward references to subpatterns in conditions such as (?(2)...) where
1157        subpattern 2 is defined later cause pcre_compile() to search forwards in
1158        the pattern for the relevant set of parentheses. This search went wrong
1159        when there were unescaped parentheses in a character class, parentheses
1160        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1161    
1162    33. "Subroutine" calls and backreferences were previously restricted to
1163        referencing subpatterns earlier in the regex. This restriction has now
1164        been removed.
1165    
1166    34. Added a number of extra features that are going to be in Perl 5.10. On the
1167        whole, these are just syntactic alternatives for features that PCRE had
1168        previously implemented using the Python syntax or my own invention. The
1169        other formats are all retained for compatibility.
1170    
1171        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1172            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1173            also .NET compatible.
1174    
1175        (b) A recursion or subroutine call to a named group can now be defined as
1176            (?&name) as well as (?P>name).
1177    
1178        (c) A backreference to a named group can now be defined as \k<name> or
1179            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1180            5.10, are also .NET compatible.
1181    
1182        (d) A conditional reference to a named group can now use the syntax
1183            (?(<name>) or (?('name') as well as (?(name).
1184    
1185        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1186            groups (named and numbered) that are never evaluated inline, but can be
1187            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1188            is always false. There may be only one alternative in such a group.
1189    
1190        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1191            as the simple (?(R). The condition is true only if the most recent
1192            recursion is that of the given number or name. It does not search out
1193            through the entire recursion stack.
1194    
1195        (g) The escape \gN or \g{N} has been added, where N is a positive or
1196            negative number, specifying an absolute or relative reference.
1197    
1198    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1199        some "unreachable code" warnings.
1200    
1201    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1202        things, this adds five new scripts.
1203    
1204    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1205        There were also incompatibilities regarding the handling of \Q..\E inside
1206        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1207        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1208    
1209    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1210        matches an empty string, and forcibly breaks the loop. There were bugs in
1211        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1212        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1213        separate and independent bugs (that affected different cases) have been
1214        fixed.
1215    
1216    39. Refactored the code to abolish the use of different opcodes for small
1217        capturing bracket numbers. This is a tidy that I avoided doing when I
1218        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1219        The new approach is not only tidier, it makes it possible to reduce the
1220        memory needed to fix the previous bug (38).
1221    
1222    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1223        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1224        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1225        mode.
1226    
1227    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1228        report.
1229    
1230    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1231        copy construction and assignment in the C++ wrapper.
1232    
1233    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1234        couple of bugs that could have given wrong results in the "--newline=crlf"
1235        case.
1236    
1237    44. Added a number of casts and did some reorganization of signed/unsigned int
1238        variables following suggestions from Dair Grant. Also renamed the variable
1239        "this" as "item" because it is a C++ keyword.
1240    
1241    45. Arranged for dftables to add
1242    
1243          #include "pcre_internal.h"
1244    
1245        to pcre_chartables.c because without it, gcc 4.x may remove the array
1246        definition from the final binary if PCRE is built into a static library and
1247        dead code stripping is activated.
1248    
1249    46. For an unanchored pattern, if a match attempt fails at the start of a
1250        newline sequence, and the newline setting is CRLF or ANY, and the next two
1251        characters are CRLF, advance by two characters instead of one.
1252    
1253    
1254    Version 6.7 04-Jul-06
1255    ---------------------
1256    
1257     1. In order to handle tests when input lines are enormously long, pcretest has
1258        been re-factored so that it automatically extends its buffers when
1259        necessary. The code is crude, but this _is_ just a test program. The
1260        default size has been increased from 32K to 50K.
1261    
1262     2. The code in pcre_study() was using the value of the re argument before
1263        testing it for NULL. (Of course, in any sensible call of the function, it
1264        won't be NULL.)
1265    
1266     3. The memmove() emulation function in pcre_internal.h, which is used on
1267        systems that lack both memmove() and bcopy() - that is, hardly ever -
1268        was missing a "static" storage class specifier.
1269    
1270     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1271        containing an extended class (one that cannot be represented by a bitmap
1272        because it contains high-valued characters or Unicode property items, e.g.
1273        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1274        pattern, but PCRE should not loop if you do not (it no longer does).
1275        [Detail: two cases were found: (a) a repeated subpattern containing an
1276        extended class; (b) a recursive reference to a subpattern that followed a
1277        previous extended class. It wasn't skipping over the extended class
1278        correctly when UTF-8 mode was not set.]
1279    
1280     5. A negated single-character class was not being recognized as fixed-length
1281        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1282        compile error "lookbehind assertion is not fixed length".
1283    
1284     6. The RunPerlTest auxiliary script was showing an unexpected difference
1285        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1286        write a Perl script that can interpret lines of an input file either as
1287        byte characters or as UTF-8, which is what "perltest" was being required to
1288        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1289        can't do is switch easily at run time between having the "use utf8;" pragma
1290        or not. In the end, I fudged it by using the RunPerlTest script to insert
1291        "use utf8;" explicitly for the UTF-8 tests.
1292    
1293     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1294        the end of the subject string, contrary to the documentation and to what
1295        Perl does. This was true of both matching functions. Now it matches only at
1296        the start of the subject and immediately after *internal* newlines.
1297    
1298     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1299        a pointer to an int instead of a pointer to an unsigned long int. This
1300        caused problems on 64-bit systems.
1301    
1302     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1303        instance of the 'standard' template library not being so standard".
1304    
1305    10. There was no check on the number of named subpatterns nor the maximum
1306        length of a subpattern name. The product of these values is used to compute
1307        the size of the memory block for a compiled pattern. By supplying a very
1308        long subpattern name and a large number of named subpatterns, the size
1309        computation could be caused to overflow. This is now prevented by limiting
1310        the length of names to 32 characters, and the number of named subpatterns
1311        to 10,000.
1312    
1313    11. Subpatterns that are repeated with specific counts have to be replicated in
1314        the compiled pattern. The size of memory for this was computed from the
1315        length of the subpattern and the repeat count. The latter is limited to
1316        65535, but there was no limit on the former, meaning that integer overflow
1317        could in principle occur. The compiled length of a repeated subpattern is
1318        now limited to 30,000 bytes in order to prevent this.
1319    
1320    12. Added the optional facility to have named substrings with the same name.
1321    
1322    13. Added the ability to use a named substring as a condition, using the
1323        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1324        are numbers (not recommended). Forward references are permitted.
1325    
1326    14. Added forward references in named backreferences (if you see what I mean).
1327    
1328    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1329        pattern could run off the end of the subject. For example, the pattern
1330        "(?s)(.{1,5})"8 did this with the subject "ab".
1331    
1332    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1333        PCRE_CASELESS was set when matching characters that were quantified with ?
1334        or *.
1335    
1336    17. A character class other than a single negated character that had a minimum
1337        but no maximum quantifier - for example [ab]{6,} - was not handled
1338        correctly by pce_dfa_exec(). It would match only one character.
1339    
1340    18. A valid (though odd) pattern that looked like a POSIX character
1341        class but used an invalid character after [ (for example [[,abc,]]) caused
1342        pcre_compile() to give the error "Failed: internal error: code overflow" or
1343        in some cases to crash with a glibc free() error. This could even happen if
1344        the pattern terminated after [[ but there just happened to be a sequence of
1345        letters, a binary zero, and a closing ] in the memory that followed.
1346    
1347    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1348        over the years. Originally (before any Unicode support), just the bottom 8
1349        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1350        output from "man perlunicode" includes this:
1351    
1352          The regular expression compiler produces polymorphic opcodes.  That
1353          is, the pattern adapts to the data and automatically switches to
1354          the Unicode character scheme when presented with Unicode data--or
1355          instead uses a traditional byte scheme when presented with byte
1356          data.
1357    
1358        Sadly, a wide octal escape does not cause a switch, and in a string with
1359        no other multibyte characters, these octal escapes are treated as before.
1360        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1361        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1362        Unicode string.
1363    
1364        I have not perpetrated such confusion in PCRE. Up till now, it took just
1365        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1366        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1367        translate to the appropriate multibyte character.
1368    
1369    29. Applied some refactoring to reduce the number of warnings from Microsoft
1370        and Borland compilers. This has included removing the fudge introduced
1371        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1372        a warning about an unused variable.
1373    
1374    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1375        characters since release 4.0, because Perl (from release 5.004) does not.
1376        [Or at least, is documented not to: some releases seem to be in conflict
1377        with the documentation.] However, when a pattern was studied with
1378        pcre_study() and all its branches started with \s, PCRE still included VT
1379        as a possible starting character. Of course, this did no harm; it just
1380        caused an unnecessary match attempt.
1381    
1382    22. Removed a now-redundant internal flag bit that recorded the fact that case
1383        dependency changed within the pattern. This was once needed for "required
1384        byte" processing, but is no longer used. This recovers a now-scarce options
1385        bit. Also moved the least significant internal flag bit to the most-
1386        significant bit of the word, which was not previously used (hangover from
1387        the days when it was an int rather than a uint) to free up another bit for
1388        the future.
1389    
1390    23. Added support for CRLF line endings as well as CR and LF. As well as the
1391        default being selectable at build time, it can now be changed at runtime
1392        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1393        specify that it is scanning data with non-default line endings.
1394    
1395    24. Changed the definition of CXXLINK to make it agree with the definition of
1396        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1397    
1398    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1399        recursions. This makes a big different to stack usage for some patterns.
1400    
1401    26. If a subpattern containing a named recursion or subroutine reference such
1402        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1403        the space required for the compiled pattern went wrong and gave too small a
1404        value. Depending on the environment, this could lead to "Failed: internal
1405        error: code overflow at offset 49" or "glibc detected double free or
1406        corruption" errors.
1407    
1408    27. Applied patches from Google (a) to support the new newline modes and (b) to
1409        advance over multibyte UTF-8 characters in GlobalReplace.
1410    
1411    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1412        difference for some implementation of PCRE in some Windows version.
1413    
1414    29. Added some extra testing facilities to pcretest:
1415    
1416        \q<number>   in a data line sets the "match limit" value
1417        \Q<number>   in a data line sets the "match recursion limt" value
1418        -S <number>  sets the stack size, where <number> is in megabytes
1419    
1420        The -S option isn't available for Windows.
1421    
1422    
1423    Version 6.6 06-Feb-06
1424    ---------------------
1425    
1426     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1427        in pcreposix.h. I have copied the definition from pcre.h.
1428    
1429     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1430        because pcre.h is no longer a built file.
1431    
1432     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1433        not normally included in the compiled code.
1434    
1435    
1436    Version 6.5 01-Feb-06
1437    ---------------------
1438    
1439     1. When using the partial match feature with pcre_dfa_exec(), it was not
1440        anchoring the second and subsequent partial matches at the new starting
1441        point. This could lead to incorrect results. For example, with the pattern
1442        /1234/, partially matching against "123" and then "a4" gave a match.
1443    
1444     2. Changes to pcregrep:
1445    
1446        (a) All non-match returns from pcre_exec() were being treated as failures
1447            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1448            error message is output. Some extra information is given for the
1449            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1450            probably the only errors that are likely to be caused by users (by
1451            specifying a regex that has nested indefinite repeats, for instance).
1452            If there are more than 20 of these errors, pcregrep is abandoned.
1453    
1454        (b) A binary zero was treated as data while matching, but terminated the
1455            output line if it was written out. This has been fixed: binary zeroes
1456            are now no different to any other data bytes.
1457    
1458        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1459            used to set a locale for matching. The --locale=xxxx long option has
1460            been added (no short equivalent) to specify a locale explicitly on the
1461            pcregrep command, overriding the environment variables.
1462    
1463        (d) When -B was used with -n, some line numbers in the output were one less
1464            than they should have been.
1465    
1466        (e) Added the -o (--only-matching) option.
1467    
1468        (f) If -A or -C was used with -c (count only), some lines of context were
1469            accidentally printed for the final match.
1470    
1471        (g) Added the -H (--with-filename) option.
1472    
1473        (h) The combination of options -rh failed to suppress file names for files
1474            that were found from directory arguments.
1475    
1476        (i) Added the -D (--devices) and -d (--directories) options.
1477    
1478        (j) Added the -F (--fixed-strings) option.
1479    
1480        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1481    
1482        (l) Added the --colo(u)r option.
1483    
1484        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1485            is not present by default.
1486    
1487     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1488        items such as (?R) or (?1), when the recursion could match a number of
1489        alternatives. If it matched one of the alternatives, but subsequently,
1490        outside the recursion, there was a failure, the code tried to back up into
1491        the recursion. However, because of the way PCRE is implemented, this is not
1492        possible, and the result was an incorrect result from the match.
1493    
1494        In order to prevent this happening, the specification of recursion has
1495        been changed so that all such subpatterns are automatically treated as
1496        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1497    
1498     4. I had overlooked the fact that, in some locales, there are characters for
1499        which isalpha() is true but neither isupper() nor islower() are true. In
1500        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1501        and ordfeminine) are like this. This affected the treatment of \w and \W
1502        when they appeared in character classes, but not when they appeared outside
1503        a character class. The bit map for "word" characters is now created
1504        separately from the results of isalnum() instead of just taking it from the
1505        upper, lower, and digit maps. (Plus the underscore character, of course.)
1506    
1507     5. The above bug also affected the handling of POSIX character classes such as
1508        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1509        permanent tables. Instead, the bit maps for such a class were previously
1510        created as the appropriate unions of the upper, lower, and digit bitmaps.
1511        Now they are created by subtraction from the [[:word:]] class, which has
1512        its own bitmap.
1513    
1514     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1515        It is created by subtracting the vertical space characters (\x09, \x0a,
1516        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1517        subtraction was done in the overall bitmap for a character class, meaning
1518        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1519        be recognized. This bug has been fixed.
1520    
1521     7. Patches from the folks at Google:
1522    
1523          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1524          real life, but is still worth protecting against".
1525    
1526          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1527          regular expressions".
1528    
1529          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1530          have it.
1531    
1532          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1533          "configure" and the latter not, in order to fix a problem somebody had
1534          with compiling the Arg class on HP-UX.
1535    
1536          (e) Improve the error-handling of the C++ wrapper a little bit.
1537    
1538          (f) New tests for checking recursion limiting.
1539    
1540     8. The pcre_memmove() function, which is used only if the environment does not
1541        have a standard memmove() function (and is therefore rarely compiled),
1542        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1543        returning a result (though PCRE never actually uses the result).
1544    
1545     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1546        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1547        returned instead of calling malloc() with an overflowing number that would
1548        most likely cause subsequent chaos.
1549    
1550    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1551    
1552    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1553        with this option is matched, the nmatch and pmatch options of regexec() are
1554        ignored.
1555    
1556    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1557        provided in case anyone wants to the the POSIX interface with UTF-8
1558        strings.
1559    
1560    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1561        C++ linking (needed for some HP-UX environments).
1562    
1563    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1564        (unused parameter) and in the pcre_printint() function (omitted "default"
1565        switch label when the default is to do nothing).
1566    
1567    15. Added some code to make it possible, when PCRE is compiled as a C++
1568        library, to replace subject pointers for pcre_exec() with a smart pointer
1569        class, thus making it possible to process discontinuous strings.
1570    
1571    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1572        much the same function. They were added by different people who were trying
1573        to make PCRE easy to compile on non-Unix systems. It has been suggested
1574        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1575        for compiling on Windows systems. I have therefore replaced it with
1576        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1577        defaults to "extern" for C or "extern C" for C++, which works fine on
1578        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1579        SCOPE with something explicit in config.h. In addition:
1580    
1581        (a) pcreposix.h still had just "extern" instead of either of these macros;
1582            I have replaced it with PCRE_DATA_SCOPE.
1583    
1584        (b) Functions such as _pcre_xclass(), which are internal to the library,
1585            but external in the C sense, all had PCRE_EXPORT in their definitions.
1586            This is apparently wrong for the Windows case, so I have removed it.
1587            (It makes no difference on Unix-like systems.)
1588    
1589    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1590        of recursive calls to match(). This is different to MATCH_LIMIT because
1591        that limits the total number of calls to match(), not all of which increase
1592        the depth of recursion. Limiting the recursion depth limits the amount of
1593        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1594        when PCRE is compiled, and changed at run time. A patch from Google adds
1595        this functionality to the C++ interface.
1596    
1597    18. Changes to the handling of Unicode character properties:
1598    
1599        (a) Updated the table to Unicode 4.1.0.
1600    
1601        (b) Recognize characters that are not in the table as "Cn" (undefined).
1602    
1603        (c) I revised the way the table is implemented to a much improved format
1604            which includes recognition of ranges. It now supports the ranges that
1605            are defined in UnicodeData.txt, and it also amalgamates other
1606            characters into ranges. This has reduced the number of entries in the
1607            table from around 16,000 to around 3,000, thus reducing its size
1608            considerably. I realized I did not need to use a tree structure after
1609            all - a binary chop search is just as efficient. Having reduced the
1610            number of entries, I extended their size from 6 bytes to 8 bytes to
1611            allow for more data.
1612    
1613        (d) Added support for Unicode script names via properties such as \p{Han}.
1614    
1615    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1616        matching that character.
1617    
1618    20. When matching a repeated Unicode property with a minimum greater than zero,
1619        (for example \pL{2,}), PCRE could look past the end of the subject if it
1620        reached it while seeking the minimum number of characters. This could
1621        happen only if some of the characters were more than one byte long, because
1622        there is a check for at least the minimum number of bytes.
1623    
1624    21. Refactored the implementation of \p and \P so as to be more general, to
1625        allow for more different types of property in future. This has changed the
1626        compiled form incompatibly. Anybody with saved compiled patterns that use
1627        \p or \P will have to recompile them.
1628    
1629    22. Added "Any" and "L&" to the supported property types.
1630    
1631    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1632        but give a compile time error if the value is greater than 0xff.
1633    
1634    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1635        accidentally not being installed or uninstalled.
1636    
1637    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1638        made were to insert the current release number. This seemed silly, because
1639        it made things harder for people building PCRE on systems that don't run
1640        "configure". I have turned pcre.h into a distributed file, no longer built
1641        by "configure", with the version identification directly included. There is
1642        no longer a pcre.h.in file.
1643    
1644        However, this change necessitated a change to the pcre-config script as
1645        well. It is built from pcre-config.in, and one of the substitutions was the
1646        release number. I have updated configure.ac so that ./configure now finds
1647        the release number by grepping pcre.h.
1648    
1649    26. Added the ability to run the tests under valgrind.
1650    
1651    
1652    Version 6.4 05-Sep-05
1653    ---------------------
1654    
1655     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1656        "--" to be printed when multiple files were scanned, even when none of the
1657        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1658        consider it to be a bug, and have restored the previous behaviour.
1659    
1660     2. A couple of code tidies to get rid of compiler warnings.
1661    
1662     3. The pcretest program used to cheat by referring to symbols in the library
1663        whose names begin with _pcre_. These are internal symbols that are not
1664        really supposed to be visible externally, and in some environments it is
1665        possible to suppress them. The cheating is now confined to including
1666        certain files from the library's source, which is a bit cleaner.
1667    
1668     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1669        file's purpose clearer.
1670    
1671     5. Reorganized pcre_ucp_findchar().
1672    
1673    
1674    Version 6.3 15-Aug-05
1675    ---------------------
1676    
1677     1. The file libpcre.pc.in did not have general read permission in the tarball.
1678    
1679     2. There were some problems when building without C++ support:
1680    
1681        (a) If C++ support was not built, "make install" and "make test" still
1682            tried to test it.
1683    
1684        (b) There were problems when the value of CXX was explicitly set. Some
1685            changes have been made to try to fix these, and ...
1686    
1687        (c) --disable-cpp can now be used to explicitly disable C++ support.
1688    
1689        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1690            backslash in a target when C++ was disabled. This confuses some
1691            versions of "make", apparently. Using an intermediate variable solves
1692            this. (Same for CPP_LOBJ.)
1693    
1694     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1695        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1696        necessary on certain architectures.
1697    
1698     4. Added a setting of -export-symbols-regex to the link command to remove
1699        those symbols that are exported in the C sense, but actually are local
1700        within the library, and not documented. Their names all begin with
1701        "_pcre_". This is not a perfect job, because (a) we have to except some
1702        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1703        available (and never for static libraries). I have made a note to try to
1704        find a way round (a) in the future.
1705    
1706    
1707    Version 6.2 01-Aug-05
1708    ---------------------
1709    
1710     1. There was no test for integer overflow of quantifier values. A construction
1711        such as {1111111111111111} would give undefined results. What is worse, if
1712        a minimum quantifier for a parenthesized subpattern overflowed and became
1713        negative, the calculation of the memory size went wrong. This could have
1714        led to memory overwriting.
1715    
1716     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1717    
1718     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1719        operating environments where this matters.
1720    
1721     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1722        PCRE options from within the C++ wrapper.
1723    
1724     5. Named capturing subpatterns were not being correctly counted when a pattern
1725        was compiled. This caused two problems: (a) If there were more than 100
1726        such subpatterns, the calculation of the memory needed for the whole
1727        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1728        back references of the form \12, where the number was greater than 9, were
1729        not recognized as back references, even though there were sufficient
1730        previous subpatterns.
1731    
1732     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1733        versions of gcc, e.g. 2.95.4.
1734    
1735    
1736    Version 6.1 21-Jun-05
1737    ---------------------
1738    
1739     1. There was one reference to the variable "posix" in pcretest.c that was not
1740        surrounded by "#if !defined NOPOSIX".
1741    
1742     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1743        the cross-check on the old pcre_info() function, for the benefit of the
1744        cut-down version of PCRE that is currently imported into Exim.
1745    
1746     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1747        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1748        patterns that start (?i) but I don't think that matters. The use of (?i) is
1749        just an example; this all applies to the other options as well.
1750    
1751     4. Since libtool seems to echo the compile commands it is issuing, the output
1752        from "make" can be reduced a bit by putting "@" in front of each libtool
1753        compile command.
1754    
1755     5. Patch from the folks at Google for configure.in to be a bit more thorough
1756        in checking for a suitable C++ installation before trying to compile the
1757        C++ stuff. This should fix a reported problem when a compiler was present,
1758        but no suitable headers.
1759    
1760     6. The man pages all had just "PCRE" as their title. I have changed them to
1761        be the relevant file name. I have also arranged that these names are
1762        retained in the file doc/pcre.txt, which is a concatenation in text format
1763        of all the man pages except the little individual ones for each function.
1764    
1765     7. The NON-UNIX-USE file had not been updated for the different set of source
1766        files that come with release 6. I also added a few comments about the C++
1767        wrapper.
1768    
1769    
1770    Version 6.0 07-Jun-05
1771    ---------------------
1772    
1773     1. Some minor internal re-organization to help with my DFA experiments.
1774    
1775     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1776        didn't matter for the library itself when fully configured, but did matter
1777        when compiling without UCP support, or within Exim, where the ucp files are
1778        not imported.
1779    
1780     3. Refactoring of the library code to split up the various functions into
1781        different source modules. The addition of the new DFA matching code (see
1782        below) to a single monolithic source would have made it really too
1783        unwieldy, quite apart from causing all the code to be include in a
1784        statically linked application, when only some functions are used. This is
1785        relevant even without the DFA addition now that patterns can be compiled in
1786        one application and matched in another.
1787    
1788        The downside of splitting up is that there have to be some external
1789        functions and data tables that are used internally in different modules of
1790        the library but which are not part of the API. These have all had their
1791        names changed to start with "_pcre_" so that they are unlikely to clash
1792        with other external names.
1793    
1794     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1795        a different (DFA) algorithm. Although it is slower than the original
1796        function, it does have some advantages for certain types of matching
1797        problem.
1798    
1799     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1800        including restarting after a partial match.
1801    
1802     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1803        defined when compiling for Windows was sent to me. I have put it into the
1804        code, though I have no means of testing or verifying it.
1805    
1806     7. Added the pcre_refcount() auxiliary function.
1807    
1808     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1809        match before or at the first newline in the subject string. In pcretest,
1810        the /f option on a pattern can be used to set this.
1811    
1812     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1813        would behave wrongly. This has been present in PCRE since release 4.0.
1814    
1815    10. A number of changes to the pcregrep command:
1816    
1817        (a) Refactored how -x works; insert ^(...)$ instead of setting
1818            PCRE_ANCHORED and checking the length, in preparation for adding
1819            something similar for -w.
1820    
1821        (b) Added the -w (match as a word) option.
1822    
1823        (c) Refactored the way lines are read and buffered so as to have more
1824            than one at a time available.
1825    
1826        (d) Implemented a pcregrep test script.
1827    
1828        (e) Added the -M (multiline match) option. This allows patterns to match
1829            over several lines of the subject. The buffering ensures that at least
1830            8K, or the rest of the document (whichever is the shorter) is available
1831            for matching (and similarly the previous 8K for lookbehind assertions).
1832    
1833        (f) Changed the --help output so that it now says
1834    
1835              -w, --word-regex(p)
1836    
1837            instead of two lines, one with "regex" and the other with "regexp"
1838            because that confused at least one person since the short forms are the
1839            same. (This required a bit of code, as the output is generated
1840            automatically from a table. It wasn't just a text change.)
1841    
1842        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1843            option but starts with a hyphen. Could be a pattern or a path name
1844            starting with a hyphen, for instance.
1845    
1846        (h) "-" can be given as a file name to represent stdin.
1847    
1848        (i) When file names are being printed, "(standard input)" is used for
1849            the standard input, for compatibility with GNU grep. Previously
1850            "<stdin>" was used.
1851    
1852        (j) The option --label=xxx can be used to supply a name to be used for
1853            stdin when file names are being printed. There is no short form.
1854    
1855        (k) Re-factored the options decoding logic because we are going to add
1856            two more options that take data. Such options can now be given in four
1857            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1858    
1859        (l) Added the -A, -B, and -C options for requesting that lines of context
1860            around matches be printed.
1861    
1862        (m) Added the -L option to print the names of files that do not contain
1863            any matching lines, that is, the complement of -l.
1864    
1865        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1866            continue to scan other files.
1867    
1868        (o) The -s option was incorrectly implemented. For compatibility with other
1869            greps, it now suppresses the error message for a non-existent or non-
1870            accessible file (but not the return code). There is a new option called
1871            -q that suppresses the output of matching lines, which was what -s was
1872            previously doing.
1873    
1874        (p) Added --include and --exclude options to specify files for inclusion
1875            and exclusion when recursing.
1876    
1877    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1878        Hopefully, it now does.
1879    
1880    12. Missing cast in pcre_study().
1881    
1882    13. Added an "uninstall" target to the makefile.
1883    
1884    14. Replaced "extern" in the function prototypes in Makefile.in with
1885        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1886        world, but is set differently for Windows.
1887    
1888    15. Added a second compiling function called pcre_compile2(). The only
1889        difference is that it has an extra argument, which is a pointer to an
1890        integer error code. When there is a compile-time failure, this is set
1891        non-zero, in addition to the error test pointer being set to point to an
1892        error message. The new argument may be NULL if no error number is required
1893        (but then you may as well call pcre_compile(), which is now just a
1894        wrapper). This facility is provided because some applications need a
1895        numeric error indication, but it has also enabled me to tidy up the way
1896        compile-time errors are handled in the POSIX wrapper.
1897    
1898    16. Added VPATH=.libs to the makefile; this should help when building with one
1899        prefix path and installing with another. (Or so I'm told by someone who
1900        knows more about this stuff than I do.)
1901    
1902    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1903        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1904        match everything, including newlines. This is not POSIX-compatible, but
1905        somebody wanted the feature. From pcretest it can be activated by using
1906        both the P and the s flags.
1907    
1908    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1909    
1910    19. libpcre.pc was being incorrectly installed as executable.
1911    
1912    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1913        it now also looks for '\r' so that it will work unmodified on Windows.
1914    
1915    21. Added Google's contributed C++ wrapper to the distribution.
1916    
1917    22. Added some untidy missing memory free() calls in pcretest, to keep
1918        Electric Fence happy when testing.
1919    
1920    
1921    
1922    Version 5.0 13-Sep-04
1923    ---------------------
1924    
1925     1. Internal change: literal characters are no longer packed up into items
1926        containing multiple characters in a single byte-string. Each character
1927        is now matched using a separate opcode. However, there may be more than one
1928        byte in the character in UTF-8 mode.
1929    
1930     2. The pcre_callout_block structure has two new fields: pattern_position and
1931        next_item_length. These contain the offset in the pattern to the next match
1932        item, and its length, respectively.
1933    
1934     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1935        insertion of callouts before each pattern item. Added the /C option to
1936        pcretest to make use of this.
1937    
1938     4. On the advice of a Windows user, the lines
1939    
1940          #if defined(_WIN32) || defined(WIN32)
1941          _setmode( _fileno( stdout ), 0x8000 );
1942          #endif  /* defined(_WIN32) || defined(WIN32) */
1943    
1944        have been added to the source of pcretest. This apparently does useful
1945        magic in relation to line terminators.
1946    
1947     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1948        for the benefit of those environments where the "b" makes a difference.
1949    
1950     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1951        to know about it. I have put a hack into configure.in that adds in code
1952        to set GCC=yes if CC=icc. This seems to end up at a point in the
1953        generated configure script that is early enough to affect the setting of
1954        compiler options, which is what is needed, but I have no means of testing
1955        whether it really works. (The user who reported this had patched the
1956        generated configure script, which of course I cannot do.)
1957    
1958        LATER: After change 22 below (new libtool files), the configure script
1959        seems to know about icc (and also ecc). Therefore, I have commented out
1960        this hack in configure.in.
1961    
1962     7. Added support for pkg-config (2 patches were sent in).
1963    
1964     8. Negated POSIX character classes that used a combination of internal tables
1965        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1966        [[:^ascii]]. Typically, they would match almost any characters. The other
1967        POSIX classes were not broken in this way.
1968    
1969     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1970        to find the match, as PCRE was deluded into thinking that the match had to
1971        start at the start point or following a newline. The same bug applied to
1972        patterns with negative forward assertions or any backward assertions
1973        preceding ".*" at the start, unless the pattern required a fixed first
1974        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1975    
1976    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1977        starting at the last subject character, bytes beyond the end of the subject
1978        string were read.
1979    
1980    11. Renamed the variable "class" as "classbits" to make life easier for C++
1981        users. (Previously there was a macro definition, but it apparently wasn't
1982        enough.)
1983    
1984    12. Added the new field "tables" to the extra data so that tables can be passed
1985        in at exec time, or the internal tables can be re-selected. This allows
1986        a compiled regex to be saved and re-used at a later time by a different
1987        program that might have everything at different addresses.
1988    
1989    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1990        -R library as well as a -L library.
1991    
1992    14. The debugging options of pcretest (-d on the command line or D on a
1993        pattern) showed incorrect output for anything following an extended class
1994        that contained multibyte characters and which was followed by a quantifier.
1995    
1996    15. Added optional support for general category Unicode character properties
1997        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1998        support. It adds about 90K to the size of the library. The meanings of the
1999        inbuilt class escapes such as \d and \s have NOT been changed.
2000    
2001    16. Updated pcredemo.c to include calls to free() to release the memory for the
2002        compiled pattern.
2003    
2004    17. The generated file chartables.c was being created in the source directory
2005        instead of in the building directory. This caused the build to fail if the
2006        source directory was different from the building directory, and was
2007        read-only.
2008    
2009    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
2010        file. No doubt somebody will tell me if they don't make sense... Also added
2011        Dan Mooney's comments about building on OpenVMS.
2012    
2013    19. Added support for partial matching via the PCRE_PARTIAL option for
2014        pcre_exec() and the \P data escape in pcretest.
2015    
2016    20. Extended pcretest with 3 new pattern features:
2017    
2018        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
2019              write the compiled pattern to the file whose name is "rest-of-line".
2020              This is a straight binary dump of the data, with the saved pointer to
2021              the character tables forced to be NULL. The study data, if any, is
2022              written too. After writing, pcretest reads a new pattern.
2023    
2024        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
2025              compiled pattern from the given file. There must not be any
2026              occurrences of "<" in the file name (pretty unlikely); if there are,
2027              pcretest will instead treat the initial "<" as a pattern delimiter.
2028              After reading in the pattern, pcretest goes on to read data lines as
2029              usual.
2030    
2031        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
2032              and 16-bit fields in a compiled pattern, to simulate a pattern that
2033              was compiled on a host of opposite endianness.
2034    
2035    21. The pcre-exec() function can now cope with patterns that were compiled on
2036        hosts of opposite endianness, with this restriction:
2037    
2038          As for any compiled expression that is saved and used later, the tables
2039          pointer field cannot be preserved; the extra_data field in the arguments
2040          to pcre_exec() should be used to pass in a tables address if a value
2041          other than the default internal tables were used at compile time.
2042    
2043    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
2044        now diagnosed as an error. Previously, most of the time, a negative number
2045        would have been treated as zero, but if in addition "ovector" was passed as
2046        NULL, a crash could occur.
2047    
2048    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
2049        new versions from the libtool 1.5 distribution (the last one is a copy of
2050        a file called libtool.m4). This seems to have fixed the need to patch
2051        "configure" to support Darwin 1.3 (which I used to do). However, I still
2052        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
2053        workstation).
2054    
2055    24. Changed the PCRE licence to be the more standard "BSD" licence.
2056    
2057    
2058    Version 4.5 01-Dec-03
2059    ---------------------
2060    
2061     1. There has been some re-arrangement of the code for the match() function so
2062        that it can be compiled in a version that does not call itself recursively.
2063        Instead, it keeps those local variables that need separate instances for
2064        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2065        needs to "recurse". Keeping track of where control must go is done by means
2066        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2067        hide most of the details from the main code, and operates only if
2068        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2069        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2070        operating.
2071    
2072        To make it easier for callers to provide specially tailored get/free
2073        functions for this usage, two new functions, pcre_stack_malloc, and
2074        pcre_stack_free, are used. They are always called in strict stacking order,
2075        and the size of block requested is always the same.
2076    
2077        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2078        PCRE has been compiled to use the stack or the heap for recursion. The
2079        -C option of pcretest uses this to show which version is compiled.
2080    
2081        A new data escape \S, is added to pcretest; it causes the amounts of store
2082        obtained and freed by both kinds of malloc/free at match time to be added
2083        to the output.
2084    
2085     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2086        what's available on my current Linux desktop machine.
2087    
2088     3. When matching a UTF-8 string, the test for a valid string at the start has
2089        been extended. If start_offset is not zero, PCRE now checks that it points
2090        to a byte that is the start of a UTF-8 character. If not, it returns
2091        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2092        this is necessary because there may be backward assertions in the pattern.
2093        When matching the same subject several times, it may save resources to use
2094        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2095    
2096     4. The code for checking the validity of UTF-8 strings has been tightened so
2097        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2098        containing "overlong sequences".
2099    
2100     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2101        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2102        should have been "&", but it just so happened that all the cases this let
2103        through by mistake were picked up later in the function.
2104    
2105     6. I had used a variable called "isblank" - this is a C99 function, causing
2106        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2107    
2108     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2109        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2110        so the version is shown; (c) stop "make test" echoing "./RunTest".
2111    
2112     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2113    
2114     9. The prototype for memmove() for systems that don't have it was using
2115        size_t, but the inclusion of the header that defines size_t was later. I've
2116        moved the #includes for the C headers earlier to avoid this.
2117    
2118    10. Added some adjustments to the code to make it easier to compiler on certain
2119        special systems:
2120    
2121          (a) Some "const" qualifiers were missing.
2122          (b) Added the macro EXPORT before all exported functions; by default this
2123              is defined to be empty.
2124          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2125              that it reads its output file name as an argument instead of writing
2126              to the standard output and assuming this can be redirected.
2127    
2128    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2129        class containing characters with values greater than 255, PCRE compilation
2130        went into a loop.
2131    
2132    12. A recursive reference to a subpattern that was within another subpattern
2133        that had a minimum quantifier of zero caused PCRE to crash. For example,
2134        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2135        recursion. If the recursively-called subpattern itself had a zero repeat,
2136        that was OK.
2137    
2138    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2139        buffer into which it was copied (for escape processing) was still set at
2140        1024, so long lines caused crashes.
2141    
2142    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2143        "internal error: code overflow...". This applied to any character class
2144        that was followed by a possessive quantifier.
2145    
2146    15. Modified the Makefile to add libpcre.la as a prerequisite for
2147        libpcreposix.la because I was told this is needed for a parallel build to
2148        work.
2149    
2150    16. If a pattern that contained .* following optional items at the start was
2151        studied, the wrong optimizing data was generated, leading to matching
2152        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2153        matching string must start with a or b or c. The correct conclusion for
2154        this pattern is that a match can start with any character.
2155    
2156    
2157    Version 4.4 13-Aug-03
2158    ---------------------
2159    
2160     1. In UTF-8 mode, a character class containing characters with values between
2161        127 and 255 was not handled correctly if the compiled pattern was studied.
2162        In fixing this, I have also improved the studying algorithm for such
2163        classes (slightly).
2164    
2165     2. Three internal functions had redundant arguments passed to them. Removal
2166        might give a very teeny performance improvement.
2167    
2168     3. Documentation bug: the value of the capture_top field in a callout is *one
2169        more than* the number of the hightest numbered captured substring.
2170    
2171     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
2172        in incorrectly linking with a previously installed version. They now link
2173        explicitly with libpcre.la.
2174    
2175     5. configure.in no longer needs to recognize Cygwin specially.
2176    
2177     6. A problem in pcre.in for Windows platforms is fixed.
2178    
2179     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
2180        pcretest, it used to include the size of the study block as part of its
2181        output. Unfortunately, the structure contains a field that has a different
2182        size on different hardware architectures. This meant that the tests that
2183        showed this size failed. As the block is currently always of a fixed size,
2184        this information isn't actually particularly useful in pcretest output, so
2185        I have just removed it.
2186    
2187     8. Three pre-processor statements accidentally did not start in column 1.
2188        Sadly, there are *still* compilers around that complain, even though
2189        standard C has not required this for well over a decade. Sigh.
2190    
2191     9. In pcretest, the code for checking callouts passed small integers in the
2192        callout_data field, which is a void * field. However, some picky compilers
2193        complained about the casts involved for this on 64-bit systems. Now
2194        pcretest passes the address of the small integer instead, which should get
2195        rid of the warnings.
2196    
2197    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2198        both compile and run time, and gives an error if an invalid UTF-8 sequence
2199        is found. There is a option for disabling this check in cases where the
2200        string is known to be correct and/or the maximum performance is wanted.
2201    
2202    11. In response to a bug report, I changed one line in Makefile.in from
2203    
2204            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2205        to
2206            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2207    
2208        to look similar to other lines, but I have no way of telling whether this
2209        is the right thing to do, as I do not use Windows. No doubt I'll get told
2210        if it's wrong...
2211    
2212    
2213    Version 4.3 21-May-03
2214    ---------------------
2215    
2216    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2217       Makefile.
2218    
2219    2. Some refactoring to improve the quality of the code:
2220    
2221       (i)   The utf8_table... variables are now declared "const".
2222    
2223       (ii)  The code for \cx, which used the "case flipping" table to upper case
2224             lower case letters, now just substracts 32. This is ASCII-specific,
2225             but the whole concept of \cx is ASCII-specific, so it seems
2226             reasonable.
2227    
2228       (iii) PCRE was using its character types table to recognize decimal and
2229             hexadecimal digits in the pattern. This is silly, because it handles
2230             only 0-9, a-f, and A-F, but the character types table is locale-
2231             specific, which means strange things might happen. A private
2232             table is now used for this - though it costs 256 bytes, a table is
2233             much faster than multiple explicit tests. Of course, the standard
2234             character types table is still used for matching digits in subject
2235             strings against \d.
2236    
2237       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2238             ending in _t are). So I've renamed it as ESC_tee.
2239    
2240    3. The first argument for regexec() in the POSIX wrapper should have been
2241       defined as "const".
2242    
2243    4. Changed pcretest to use malloc() for its buffers so that they can be
2244       Electric Fenced for debugging.
2245    
2246    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2247       to read one or more bytes before the start of the subject string. Often this
2248       had no effect on PCRE's behaviour, but in some circumstances it could
2249       provoke a segmentation fault.
2250    
2251    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2252       to try to read one or more bytes before the start of the subject string.
2253    
2254    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2255       UTF-8 support could misbehave in various ways if the subject string
2256       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2257       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2258       back over UTF-8 characters.)
2259    
2260    
2261    Version 4.2 14-Apr-03
2262    ---------------------
2263    
2264    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2265    
2266    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2267         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2268         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2269         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2270         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2271           and BUILD_EXEEXT
2272         Note: automatic setting of the BUILD variables is not yet working
2273         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2274           compile-time but not at link-time
2275         [LINK]: use for linking executables only
2276         make different versions for Windows and non-Windows
2277         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2278           libraries
2279         [LINK_FOR_BUILD]: new variable
2280         [OBJEXT]: use throughout
2281         [EXEEXT]: use throughout
2282         <winshared>: new target
2283         <wininstall>: new target
2284         <dftables.o>: use native compiler
2285         <dftables>: use native linker
2286         <install>: handle Windows platform correctly
2287         <clean>: ditto
2288         <check>: ditto
2289         copy DLL to top builddir before testing
2290    
2291       As part of these changes, -no-undefined was removed again. This was reported
2292       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2293       in any case.
2294    
2295    3. Some tidies to get rid of compiler warnings:
2296    
2297       . In the match_data structure, match_limit was an unsigned long int, whereas
2298         match_call_count was an int. I've made them both unsigned long ints.
2299    
2300       . In pcretest the fact that a const uschar * doesn't automatically cast to
2301         a void * provoked a warning.
2302    
2303       . Turning on some more compiler warnings threw up some "shadow" variables
2304         and a few more missing casts.
2305    
2306    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2307       option, a class that contained a single character with a value between 128
2308       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2309    
2310    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2311       option, a class that contained several characters, but with at least one
2312       whose value was between 128 and 255 caused PCRE to crash.
2313    
2314    
2315    Version 4.1 12-Mar-03
2316    ---------------------
2317    
2318    1. Compiling with gcc -pedantic found a couple of places where casts were
2319    needed, and a string in dftables.c that was longer than standard compilers are
2320    required to support.
2321    
2322    2. Compiling with Sun's compiler found a few more places where the code could
2323    be tidied up in order to avoid warnings.
2324    
2325    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2326    first of these names is deprecated in the latest Autoconf in favour of the name
2327    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2328    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2329    analogy I have changed it to CFLAGS_FOR_BUILD.
2330    
2331    4. Added -no-undefined to the linking command in the Makefile, because this is
2332    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2333    linking step for the pcreposix library.
2334    
2335    5. PCRE was failing to diagnose the case of two named groups with the same
2336    name.
2337    
2338    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2339    literal character that is needed in the subject for a match, and scans along to
2340    ensure that it is present before embarking on the full matching process. This
2341    saves time in cases of nested unlimited repeats that are never going to match.
2342    Problem: the scan can take a lot of time if the subject is very long (e.g.
2343    megabytes), thus penalizing straightforward matches. It is now done only if the
2344    amount of subject to be scanned is less than 1000 bytes.
2345    
2346    7. A lesser problem with the same optimization is that it was recording the
2347    first character of an anchored pattern as "needed", thus provoking a search
2348    right along the subject, even when the first match of the pattern was going to
2349    fail. The "needed" character is now not set for anchored patterns, unless it
2350    follows something in the pattern that is of non-fixed length. Thus, it still
2351    fulfils its original purpose of finding quick non-matches in cases of nested
2352    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2353    
2354    
2355    Version 4.0 17-Feb-03
2356    ---------------------
2357    
2358    1. If a comment in an extended regex that started immediately after a meta-item
2359    extended to the end of string, PCRE compiled incorrect data. This could lead to
2360    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2361    
2362    2. Moved to autoconf 2.53 and libtool 1.4.2.
2363    
2364    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2365    the special perltest8 script is no longer needed - all the tests can be run
2366    from a single perltest script.
2367    
2368    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2369    by \s. It has now been removed in PCRE. This means it isn't recognized as
2370    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2371    class [:space:] *does* include VT, thereby creating a mess.
2372    
2373    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2374    space and tab.
2375    
2376    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2377    its new features into the main test script, reducing the number of scripts.
2378    
2379    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2380    were backward compatible, and made the (?i) apply to the whole pattern, as if
2381    /i were given. Now it behaves more logically, and applies the option setting
2382    only to what follows. PCRE has been changed to follow suit. However, if it
2383    finds options settings right at the start of the pattern, it extracts them into
2384    the global options, as before. Thus, they show up in the info data.
2385    
2386    8. Added support for the \Q...\E escape sequence. Characters in between are
2387    treated as literals. This is slightly different from Perl in that $ and @ are
2388    also handled as literals inside the quotes. In Perl, they will cause variable
2389    interpolation. Note the following examples:
2390    
2391        Pattern            PCRE matches      Perl matches
2392    
2393        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2394        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2395        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2396    
2397    For compatibility with Perl, \Q...\E sequences are recognized inside character
2398    classes as well as outside them.
2399    
2400    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2401    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2402    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2403    signed/unsigned warnings.
2404    
2405    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2406    option for pcretest, so I've replaced it by a simple function that does just
2407    that job.
2408    
2409    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2410    "pcregrep -".
2411    
2412    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2413    Java package. This provides some syntactic sugar for simple cases of what my
2414    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2415    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2416    item, you can use this simplified notation. Note that only makes sense with
2417    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2418    greediness, whatever the setting of the PCRE_UNGREEDY option.
2419    
2420    13. A change of greediness default within a pattern was not taking effect at
2421    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2422    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2423    was abstracted outside.
2424    
2425    14. PCRE now supports the \G assertion. It is true when the current matching
2426    position is at the start point of the match. This differs from \A when the
2427    starting offset is non-zero. Used with the /g option of pcretest (or similar
2428    code), it works in the same way as it does for Perl's /g option. If all
2429    alternatives of a regex begin with \G, the expression is anchored to the start
2430    match position, and the "anchored" flag is set in the compiled expression.
2431    
2432    15. Some bugs concerning the handling of certain option changes within patterns
2433    have been fixed. These applied to options other than (?ims). For example,
2434    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2435    been the other way round. Some of this was related to change 7 above.
2436    
2437    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2438    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2439    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2440    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2441    
2442    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2443    mode. Unlike ".", it always matches newline, whatever the setting of
2444    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2445    assertions. Perl allows it, but it doesn't (in general) work because it can't
2446    calculate the length of the lookbehind. At least, that's the case for Perl
2447    5.8.0 - I've been told they are going to document that it doesn't work in
2448    future.
2449    
2450    18. Added an error diagnosis for escapes that PCRE does not support: these are
2451    \L, \l, \N, \P, \p, \U, \u, and \X.
2452    
2453    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2454    reading past the end of the pattern in cases such as /[abcd/.
2455    
2456    20. PCRE was getting more memory than necessary for patterns with classes that
2457    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2458    
2459    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2460    compiling PCRE for use with Virtual Pascal.
2461    
2462    22. Small fix to the Makefile to make it work properly if the build is done
2463    outside the source tree.
2464    
2465    23. Added a new extension: a condition to go with recursion. If a conditional
2466    subpattern starts with (?(R) the "true" branch is used if recursion has
2467    happened, whereas the "false" branch is used only at the top level.
2468    
2469    24. When there was a very long string of literal characters (over 255 bytes
2470    without UTF support, over 250 bytes with UTF support), the computation of how
2471    much memory was required could be incorrect, leading to segfaults or other
2472    strange effects.
2473    
2474    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2475    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2476    there was a subsequent back reference to those brackets. This meant that, for
2477    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2478    possible to check for precisely this case. All we can do is abandon the
2479    optimization if .* occurs inside capturing brackets when there are any back
2480    references whatsoever. (See below for a better fix that came later.)
2481    
2482    26. The handling of the optimization for finding the first character of a
2483    non-anchored pattern, and for finding a character that is required later in the
2484    match were failing in some cases. This didn't break the matching; it just
2485    failed to optimize when it could. The way this is done has been re-implemented.
2486    
2487    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2488    
2489    28. Added a new feature that provides some of the functionality that Perl
2490    provides with (?{...}). The facility is termed a "callout". The way it is done
2491    in PCRE is for the caller to provide an optional function, by setting
2492    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2493    global variable. By default it is unset, which disables all calling out. To get
2494    the function called, the regex must include (?C) at appropriate points. This
2495    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2496    This provides a means of identifying different callout points. When PCRE
2497    reaches such a point in the regex, if pcre_callout has been set, the external
2498    function is called. It is provided with data in a structure called
2499    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2500    matching continues; if it returns a non-zero value, the match at the current
2501    point fails. However, backtracking will occur if possible. [This was changed
2502    later and other features added - see item 49 below.]
2503    
2504    29. pcretest is upgraded to test the callout functionality. It provides a
2505    callout function that displays information. By default, it shows the start of
2506    the match and the current position in the text. There are some new data escapes
2507    to vary what happens:
2508    
2509        \C+         in addition, show current contents of captured substrings
2510        \C-         do not supply a callout function
2511        \C!n        return 1 when callout number n is reached
2512        \C!n!m      return 1 when callout number n is reached for the mth time
2513    
2514    30. If pcregrep was called with the -l option and just a single file name, it
2515    output "<stdin>" if a match was found, instead of the file name.
2516    
2517    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2518    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2519    pcre_exec(). This saves a malloc/free per call. The default value of
2520    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2521    when configuring.
2522    
2523    32. The default maximum size of a compiled pattern is 64K. There have been a
2524    few cases of people hitting this limit. The code now uses macros to handle the
2525    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2526    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2527    configuring. Tests 2 and 5 work only with 2-byte links because they output
2528    debugging information about compiled patterns.
2529    
2530    33. Internal code re-arrangements:
2531    
2532    (a) Moved the debugging function for printing out a compiled regex into
2533        its own source file (printint.c) and used #include to pull it into
2534        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2535        separate copies.
2536    
2537    (b) Defined the list of op-code names for debugging as a macro in
2538        internal.h so that it is next to the definition of the opcodes.
2539    
2540    (c) Defined a table of op-code lengths for simpler skipping along compiled
2541        code. This is again a macro in internal.h so that it is next to the
2542        definition of the opcodes.
2543    
2544    34. Added support for recursive calls to individual subpatterns, along the
2545    lines of Robin Houston's patch (but implemented somewhat differently).
2546    
2547    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2548    allow it to read and process whole directories in Win32. This code was
2549    contributed by Lionel Fourquaux; it has not been tested by me.
2550    
2551    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2552    used to name a group. Names consist of alphanumerics and underscores, and must
2553    be unique. Back references use the syntax (?P=name) and recursive calls use
2554    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2555    numbers. The function pcre_fullinfo() can be used after compilation to extract
2556    a name/number map. There are three relevant calls:
2557    
2558      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2559      PCRE_INFO_NAMECOUNT            yields the number of entries
2560      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2561    
2562    The map is a vector of fixed-size entries. The size of each entry depends on
2563    the length of the longest name used. The first two bytes of each entry are the
2564    group number, most significant byte first. There follows the corresponding
2565    name, zero terminated. The names are in alphabetical order.
2566    
2567    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2568    case instead of 255. Making it the same both with and without UTF-8 support
2569    means that the same test output works with both.
2570    
2571    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2572    calling malloc() with a zero argument.
2573    
2574    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2575    optimization. I've improved things by keeping a bitmap of backreferences with
2576    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2577    fact referenced, the optimization can be applied. It is unlikely that a
2578    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2579    the match to follow \n) will appear inside brackets with a number greater than
2580    31, but if it does, any back reference > 31 suppresses the optimization.
2581    
2582    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2583    of disabling numbered capturing parentheses. Any opening parenthesis that is
2584    not followed by ? behaves as if it were followed by ?: but named parentheses
2585    can still be used for capturing (and they will acquire numbers in the usual
2586    way).
2587    
2588    41. Redesigned the return codes from the match() function into yes/no/error so
2589    that errors can be passed back from deep inside the nested calls. A malloc
2590    failure while inside a recursive subpattern call now causes the
2591    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2592    
2593    42. It is now possible to set a limit on the number of times the match()
2594    function is called in a call to pcre_exec(). This facility makes it possible to
2595    limit the amount of recursion and backtracking, though not in a directly
2596    obvious way, because the match() function is used in a number of different
2597    circumstances. The count starts from zero for each position in the subject
2598    string (for non-anchored patterns). The default limit is, for compatibility, a
2599    large number, namely 10 000 000. You can change this in two ways:
2600    
2601    (a) When configuring PCRE before making, you can use --with-match-limit=n
2602        to set a default value for the compiled library.
2603    
2604    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2605        a different value is set. See 45 below.
2606    
2607    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2608    
2609    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2610    of things that can be changed at compile time. The first argument specifies
2611    what is wanted and the second points to where the information is to be placed.
2612    The current list of available information is:
2613    
2614      PCRE_CONFIG_UTF8
2615    
2616    The output is an integer that is set to one if UTF-8 support is available;
2617    otherwise it is set to zero.
2618    
2619      PCRE_CONFIG_NEWLINE
2620    
2621    The output is an integer that it set to the value of the code that is used for
2622    newline. It is either LF (10) or CR (13).
2623    
2624      PCRE_CONFIG_LINK_SIZE
2625    
2626    The output is an integer that contains the number of bytes used for internal
2627    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2628    
2629      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2630    
2631    The output is an integer that contains the threshold above which the POSIX
2632    interface uses malloc() for output vectors. See item 31 above.
2633    
2634      PCRE_CONFIG_MATCH_LIMIT
2635    
2636    The output is an unsigned integer that contains the default limit of the number
2637    of match() calls in a pcre_exec() execution. See 42 above.
2638    
2639    44. pcretest has been upgraded by the addition of the -C option. This causes it
2640    to extract all the available output from the new pcre_config() function, and to
2641    output it. The program then exits immediately.
2642    
2643    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2644    order to support additional features. One way would have been to define
2645    pcre_exec2() (for example) with extra arguments, but this would not have been
2646    extensible, and would also have required all calls to the original function to
2647    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2648    is used for passing in "extra" data from pcre_study().
2649    
2650    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2651    contains the following fields:
2652    
2653      flags         a bitmap indicating which of the following fields are set
2654      study_data    opaque data from pcre_study()
2655      match_limit   a way of specifying a limit on match() calls for a specific
2656                      call to pcre_exec()
2657      callout_data  data for callouts (see 49 below)
2658    
2659    The flag bits are also defined in pcre.h, and are
2660    
2661      PCRE_EXTRA_STUDY_DATA
2662      PCRE_EXTRA_MATCH_LIMIT
2663      PCRE_EXTRA_CALLOUT_DATA
2664    
2665    The pcre_study() function now returns one of these new pcre_extra blocks, with
2666    the actual study data pointed to by the study_data field, and the
2667    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2668    before. That is, this change is entirely upwards-compatible and requires no
2669    change to existing code.
2670    
2671    If you want to pass in additional data to pcre_exec(), you can either place it
2672    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2673    block.
2674    
2675    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2676    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2677    times with different match limits, until it finds the minimum value needed for
2678    pcre_exec() to complete. The value is then output. This can be instructive; for
2679    most simple matches the number is quite small, but for pathological cases it
2680    gets very large very quickly.
2681    
2682    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2683    returns the size of the data block pointed to by the study_data field in a
2684    pcre_extra block, that is, the value that was passed as the argument to
2685    pcre_malloc() when PCRE was getting memory in which to place the information
2686    created by pcre_study(). The fourth argument should point to a size_t variable.
2687    pcretest has been extended so that this information is shown after a successful
2688    pcre_study() call when information about the compiled regex is being displayed.
2689    
2690    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2691    because what follows is always an absolute path. (Later: it turns out that this
2692    is more than cosmetic for MinGW, because it doesn't like empty path
2693    components.)
2694    
2695    49. Some changes have been made to the callout feature (see 28 above):
2696    
2697    (i)  A callout function now has three choices for what it returns:
2698    
2699           0  =>  success, carry on matching
2700         > 0  =>  failure at this point, but backtrack if possible
2701         < 0  =>  serious error, return this value from pcre_exec()
2702    
2703         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2704         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2705         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2706         use by callout functions. It will never be used by PCRE itself.
2707    
2708    (ii) The pcre_extra structure (see 45 above) has a void * field called
2709         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2710         pcre_callout_block structure has a field of the same name. The contents of
2711         the field passed in the pcre_extra structure are passed to the callout
2712         function in the corresponding field in the callout block. This makes it
2713         easier to use the same callout-containing regex from multiple threads. For
2714         testing, the pcretest program has a new data escape
2715    
2716           \C*n        pass the number n (may be negative) as callout_data
2717    
2718         If the callout function in pcretest receives a non-zero value as
2719         callout_data, it returns that value.
2720    
2721    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2722    there were some redundant $(CFLAGS) in commands that are now specified as
2723    $(LINK), which already includes $(CFLAGS).
2724    
2725    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2726    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2727    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2728    one-byte characters throughout. Note that case-insensitive matching applies
2729    only to characters whose values are less than 256. PCRE doesn't support the
2730    notion of cases for higher-valued characters.
2731    
2732    (i)   A character class whose characters are all within 0-255 is handled as
2733          a bit map, and the map is inverted for negative classes. Previously, a
2734          character > 255 always failed to match such a class; however it should
2735          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2736    
2737    (ii)  A negated character class with a single character < 255 is coded as
2738          "not this character" (OP_NOT). This wasn't working properly when the test
2739          character was multibyte, either singly or repeated.
2740    
2741    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2742          mode, for example: \x{100}{2,3}.
2743    
2744    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2745          singly or repeated) now correctly test multibyte characters. However,
2746          PCRE doesn't recognize any characters with values greater than 255 as
2747          digits, spaces, or word characters. Such characters always match \D, \S,
2748          and \W, and never match \d, \s, or \w.
2749    
2750    (v)   Classes may now contain characters and character ranges with values
2751          greater than 255. For example: [ab\x{100}-\x{400}].
2752    
2753    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2754          PCRE in UTF-8 mode.
2755    
2756    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2757    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2758    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2759    value.)
2760    
2761    53. The single man page has become too large. I have therefore split it up into
2762    a number of separate man pages. These also give rise to individual HTML pages;
2763    these are now put in a separate directory, and there is an index.html page that
2764    lists them all. Some hyperlinking between the pages has been installed.
2765    
2766    54. Added convenience functions for handling named capturing parentheses.
2767    
2768    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2769    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2770    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2771    are faulted.
2772    
2773    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2774    calling configure. These values are used when compiling the dftables.c program
2775    which is run to generate the source of the default character tables. They
2776    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2777    you will need to set these values.
2778    
2779    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2780    
2781    
2782    Version 3.9 02-Jan-02
2783    ---------------------
2784    
2785    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2786    
2787    2. If --disable-static was given, the building process failed when trying to
2788    build pcretest and pcregrep. (For some reason it was using libtool to compile
2789    them, which is not right, as they aren't part of the library.)
2790    
2791    
2792    Version 3.8 18-Dec-01
2793    ---------------------
2794    
2795    1. The experimental UTF-8 code was completely screwed up. It was packing the
2796    bytes in the wrong order. How dumb can you get?
2797    
2798    
2799    Version 3.7 29-Oct-01
2800    ---------------------
2801    
2802    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2803    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2804    this didn't happen under Solaris 8, where I normally test things.
2805    
2806    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2807    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2808    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2809    this fix an hour or so after the initial 3.7 release.)
2810    
2811    
2812    Version 3.6 23-Oct-01
2813    ---------------------
2814    
2815    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2816    offsets passed as NULL with zero offset count.
2817    
2818    2. The config.guess and config.sub files had not been updated when I moved to
2819    the latest autoconf.
2820    
2821    
2822    Version 3.5 15-Aug-01
2823    ---------------------
2824    
2825    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2826    had been forgotten.
2827    
2828    2. By using declared but undefined structures, we can avoid using "void"
2829    definitions in pcre.h while keeping the internal definitions of the structures
2830    private.
2831    
2832    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2833    user point of view, this means that both static and shared libraries are built
2834    by default, but this can be individually controlled. More of the work of
2835    handling this static/shared cases is now inside libtool instead of PCRE's make
2836    file.
2837    
2838    4. The pcretest utility is now installed along with pcregrep because it is
2839    useful for users (to test regexs) and by doing this, it automatically gets
2840    relinked by libtool. The documentation has been turned into a man page, so
2841    there are now .1, .txt, and .html versions in /doc.
2842    
2843    5. Upgrades to pcregrep:
2844       (i)   Added long-form option names like gnu grep.
2845       (ii)  Added --help to list all options with an explanatory phrase.
2846       (iii) Added -r, --recursive to recurse into sub-directories.
2847       (iv)  Added -f, --file to read patterns from a file.
2848    
2849    6. pcre_exec() was referring to its "code" argument before testing that
2850    argument for NULL (and giving an error if it was NULL).
2851    
2852    7. Upgraded Makefile.in to allow for compiling in a different directory from
2853    the source directory.
2854    
2855    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2856    options bits, the pointer it was passed was to an int instead of to an unsigned
2857    long int. This mattered only on 64-bit systems.
2858    
2859    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2860    generated) instead of pcre.in, which it its source. Also made the same change
2861    in several of the .c files.
2862    
2863    10. A new release of gcc defines printf() as a macro, which broke pcretest
2864    because it had an ifdef in the middle of a string argument for printf(). Fixed
2865    by using separate calls to printf().
2866    
2867    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2868    script, to force use of CR or LF instead of \n in the source. On non-Unix
2869    systems, the value can be set in config.h.
2870    
2871    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2872    absolute limit. Changed the text of the error message to make this clear, and
2873    likewise updated the man page.
2874    
2875    13. The limit of 99 on the number of capturing subpatterns has been removed.
2876    The new limit is 65535, which I hope will not be a "real" limit.
2877    
2878    
2879    Version 3.4 22-Aug-00
2880    ---------------------
2881    
2882    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2883    
2884    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2885    
2886    
2887    Version 3.3 01-Aug-00
2888    ---------------------
2889    
2890    1. If an octal character was given, but the value was greater than \377, it
2891    was not getting masked to the least significant bits, as documented. This could
2892    lead to crashes in some systems.
2893    
2894    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2895    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2896    
2897    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2898    These just pass their arguments on to (pcre_free)(), but they are provided
2899    because some uses of PCRE bind it to non-C systems that can call its functions,
2900    but cannot call free() or pcre_free() directly.
2901    
2902    4. Add "make test" as a synonym for "make check". Corrected some comments in
2903    the Makefile.
2904    
2905    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2906    Makefile.
2907    
2908    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2909    command called pgrep for grepping around the active processes.
2910    
2911    7. Added the beginnings of support for UTF-8 character strings.
2912    
2913    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2914    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2915    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2916    out for the ar command.)
2917    
2918    
2919    Version 3.2 12-May-00
2920    ---------------------
2921    
2922    This is purely a bug fixing release.
2923    
2924    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2925    of ZA. This was just one example of several cases that could provoke this bug,
2926    which was introduced by change 9 of version 2.00. The code for breaking
2927    infinite loops after an iteration that matches an empty string was't working
2928    correctly.
2929    
2930    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2931    when matched against abbab (for example). After matching an empty string, it
2932    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2933    caused it to match further down the string than it should.
2934    
2935    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2936    was there because it doesn't seem to be needed, and it causes trouble on some
2937    systems, as it is not a Standard C header. It has been removed.
2938    
2939    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2940    were reported on the Macintosh. The changes were from
2941    
2942      while ((c = *(++ptr)) != 0 && c != '\n');
2943    to
2944      while ((c = *(++ptr)) != 0 && c != '\n') ;
2945    
2946    Totally extraordinary, but if that's what it takes...
2947    
2948    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2949    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2950    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2951    assumes the way PCRE uses memmove() (always moving upwards).
2952    
2953    6. PCRE is being used in one environment where strchr() is not available. There
2954    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2955    faster code anyway.
2956    
2957    
2958    Version 3.1 09-Feb-00
2959    ---------------------
2960    
2961    The only change in this release is the fixing of some bugs in Makefile.in for
2962    the "install" target:
2963    
2964    (1) It was failing to install pcreposix.h.
2965    
2966    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2967    
2968    
2969    Version 3.0 01-Feb-00
2970    ---------------------
2971    
2972    1. Add support for the /+ modifier to perltest (to output $` like it does in
2973    pcretest).
2974    
2975    2. Add support for the /g modifier to perltest.
2976    
2977    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2978    matches null strings.
2979    
2980    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2981    pattern. Perl treats empty patterns specially - it reuses the most recent
2982    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2983    effect.
2984    
2985    5. The POSIX interface was broken in that it was just handing over the POSIX
2986    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2987    required a bigger vector, with some working space on the end. This means that
2988    the POSIX wrapper now has to get and free some memory, and copy the results.
2989    
2990    6. Added some simple autoconf support, placing the test data and the
2991    documentation in separate directories, re-organizing some of the
2992    information files, and making it build pcre-config (a GNU standard). Also added
2993    libtool support for building PCRE as a shared library, which is now the
2994    default.
2995    
2996    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2997    09 are not valid octal constants. Single digits will be used for minor values
2998    less than 10.
2999    
3000    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
3001    existing programs that set these in the POSIX interface can use PCRE without
3002    modification.
3003    
3004    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
3005    return all that pcre_info() returns, plus additional data. The pcre_info()
3006    function is retained for compatibility, but is considered to be obsolete.
3007    
3008    10. Added experimental recursion feature (?R) to handle one common case that
3009    Perl 5.6 will be able to do with (?p{...}).
3010    
3011    11. Added support for POSIX character classes like [:alpha:], which Perl is
3012    adopting.
3013    
3014    
3015    Version 2.08 31-Aug-99
3016    ----------------------
3017    
3018    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
3019    trying to match at the startoffset position, but instead was moving forward to
3020    the next newline as if a previous match had failed.
3021    
3022    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
3023    and could get into a loop if a null string was matched other than at the start
3024    of the subject.
3025    
3026    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
3027    be distinguished at compile time, and for completeness also added PCRE_DATE.
3028    
3029    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
3030    in GnuWin32 environments.
3031    
3032    
3033    Version 2.07 29-Jul-99
3034    ----------------------
3035    
3036    1. The documentation is now supplied in plain text form and HTML as well as in
3037    the form of man page sources.
3038    
3039    2. C++ compilers don't like assigning (void *) values to other pointer types.
3040    In particular this affects malloc(). Although there is no problem in Standard
3041    C, I've put in casts to keep C++ compilers happy.
3042    
3043    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
3044    should be (const char *).
3045    
3046    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
3047    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
3048    However, I haven't made this a standard facility. The documentation doesn't
3049    mention it, and the Makefile doesn't support it.
3050    
3051    5. The Makefile now contains an "install" target, with editable destinations at
3052    the top of the file. The pcretest program is not installed.
3053    
3054    6. pgrep -V now gives the PCRE version number and date.
3055    
3056    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
3057    causing the entire string to be ignored, instead of just the last character.
3058    
3059    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
3060    non-matching string, it can take a very, very long time, even for strings of
3061    quite modest length, because of the nested recursion. PCRE now does better in
3062    some of these cases. It does this by remembering the last required literal
3063    character in the pattern, and pre-searching the subject to ensure it is present
3064    before running the real match. In other words, it applies a heuristic to detect
3065    some types of certain failure quickly, and in the above example, if presented
3066    with a string that has no trailing " it gives "no match" very quickly.
3067    
3068    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
3069    other alternatives are tried instead.
3070    
3071    
3072    Version 2.06 09-Jun-99
3073    ----------------------
3074    
3075    1. Change pcretest's output for amount of store used to show just the code
3076    space, because the remainder (the data block) varies in size between 32-bit and
3077    64-bit systems.
3078    
3079    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
3080    start matching at. This allows lookbehinds to work when searching for multiple
3081    occurrences in a string.
3082    
3083    3. Added additional options to pcretest for testing multiple occurrences:
3084    
3085       /+   outputs the rest of the string that follows a match
3086       /g   loops for multiple occurrences, using the new startoffset argument
3087       /G   loops for multiple occurrences by passing an incremented pointer
3088    
3089    4. PCRE wasn't doing the "first character" optimization for patterns starting
3090    with \b or \B, though it was doing it for other lookbehind assertions. That is,
3091    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
3092    the letter 'x'. On long subject strings, this gives a significant speed-up.
3093    
3094    
3095    Version 2.05 21-Apr-99
3096    ----------------------
3097    
3098    1. Changed the type of magic_number from int to long int so that it works
3099    properly on 16-bit systems.
3100    
3101    2. Fixed a bug which caused patterns starting with .* not to work correctly
3102    when the subject string contained newline characters. PCRE was assuming
3103    anchoring for such patterns in all cases, which is not correct because .* will
3104    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
3105    DOTALL is set at top level; otherwise it knows that patterns starting with .*
3106    must be retried after every newline in the subject.
3107    
3108    
3109    Version 2.04 18-Feb-99
3110    ----------------------
3111    
3112    1. For parenthesized subpatterns with repeats whose minimum was zero, the
3113    computation of the store needed to hold the pattern was incorrect (too large).
3114    If such patterns were nested a few deep, this could multiply and become a real
3115    problem.
3116    
3117    2. Added /M option to pcretest to show the memory requirement of a specific
3118    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
3119    
3120    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
3121    compiled in such a way that the backtracking after subsequent failure was
3122    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
3123    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
3124    
3125    
3126    Version 2.03 02-Feb-99
3127    ----------------------
3128    
3129    1. Fixed typo and small mistake in man page.
3130    
3131    2. Added 4th condition (GPL supersedes if conflict) and created separate
3132    LICENCE file containing the conditions.
3133    
3134    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
3135    Perl, that is the internal \ allows the delimiter to be included in the
3136    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
3137    the final delimiter, add \ to the end of the pattern (to test the error).
3138    
3139    4. Added the convenience functions for extracting substrings after a successful
3140    match. Updated pcretest to make it able to test these functions.
3141    
3142    
3143    Version 2.02 14-Jan-99
3144    ----------------------
3145    
3146    1. Initialized the working variables associated with each extraction so that
3147    their saving and restoring doesn't refer to uninitialized store.
3148    
3149    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
3150    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
3151    fix the problem.
3152    
3153    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
3154    calls, and wasn't printing the correct value for compiling calls. Increased the
3155    default value of LOOPREPEAT, and the number of significant figures in the
3156    times.
3157    
3158    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
3159    
3160    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
3161    a building problem on Windows NT with a FAT file system.
3162    
3163    
3164    Version 2.01 21-Oct-98
3165    ----------------------
3166    
3167    1. Changed the API for pcre_compile() to allow for the provision of a pointer
3168    to character tables built by pcre_maketables() in the current locale. If NULL
3169    is passed, the default tables are used.
3170    
3171    
3172    Version 2.00 24-Sep-98
3173    ----------------------
3174    
3175    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
3176    it any more.
3177    
3178    2. Allow quantification of (?>) groups, and make it work correctly.
3179    
3180    3. The first character computation wasn't working for (?>) groups.
3181    
3182    4. Correct the implementation of \Z (it is permitted to match on the \n at the
3183    end of the subject) and add 5.005's \z, which really does match only at the
3184    very end of the subject.
3185    
3186    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
3187    
3188    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3189    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3190    localized options. All options to pcre_study() were also removed.
3191    
3192    7. Add other new features from 5.005:
3193    
3194       $(?<=           positive lookbehind
3195       $(?<!           negative lookbehind
3196       (?imsx-imsx)    added the unsetting capability
3197                       such a setting is global if at outer level; local otherwise
3198       (?imsx-imsx:)   non-capturing groups with option setting
3199       (?(cond)re|re)  conditional pattern matching
3200    
3201       A backreference to itself in a repeated group matches the previous
3202       captured string.
3203    
3204    8. General tidying up of studying (both automatic and via "study")
3205    consequential on the addition of new assertions.
3206    
3207    9. As in 5.005, unlimited repeated groups that could match an empty substring
3208    are no longer faulted at compile time. Instead, the loop is forcibly broken at
3209    runtime if any iteration does actually match an empty substring.
3210    
3211    10. Include the RunTest script in the distribution.
3212    
3213    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3214    discrepancies, some of which were old and were also with respect to 5.004. They
3215    have now been fixed.
3216    
3217    
3218    Version 1.09 28-Apr-98
3219    ----------------------
3220    
3221    1. A negated single character class followed by a quantifier with a minimum
3222    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
3223    program crashes, or just wrong answers. This did not apply to negated classes
3224    containing more than one character, or to minima other than one.
3225    
3226    
3227    Version 1.08 27-Mar-98
3228    ----------------------
3229    
3230    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3231    
3232    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3233    latter must appear before anything that relies on it in the pattern.
3234    
3235    
3236    Version 1.07 16-Feb-98
3237    ----------------------
3238    
3239    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3240    repeat of a potentially empty string).
3241    
3242    
3243    Version 1.06 23-Jan-98
3244    ----------------------
3245    
3246    1. Added Markus Oberhumer's little patches for C++.
3247    
3248    2. Literal strings longer than 255 characters were broken.
3249    
3250    
3251    Version 1.05 23-Dec-97
3252    ----------------------
3253    
3254    1. Negated character classes containing more than one character were failing if
3255    PCRE_CASELESS was set at run time.
3256    
3257    
3258    Version 1.04 19-Dec-97
3259    ----------------------
3260    
3261    1. Corrected the man page, where some "const" qualifiers had been omitted.
3262    
3263    2. Made debugging output print "{0,xxx}" instead of just "{,xxx}" to agree with
3264    input syntax.
3265    
3266    3. Fixed memory leak which occurred when a regex with back references was
3267    matched with an offsets vector that wasn't big enough. The temporary memory
3268    that is used in this case wasn't being freed if the match failed.
3269    
3270    4. Tidied pcretest to ensure it frees memory that it gets.
3271    
3272    5. Temporary memory was being obtained in the case where the passed offsets
3273    vector was exactly big enough.
3274    
3275    6. Corrected definition of offsetof() from change 5 below.
3276    
3277    7. I had screwed up change 6 below and broken the rules for the use of
3278    setjmp(). Now fixed.
3279    
3280    
3281    Version 1.03 18-Dec-97
3282    ----------------------
3283    
3284    1. A erroneous regex with a missing opening parenthesis was correctly
3285    diagnosed, but PCRE attempted to access brastack[-1], which could cause crashes
3286    on some systems.
3287    
3288    2. Replaced offsetof(real_pcre, code) by offsetof(real_pcre, code[0]) because
3289    it was reported that one broken compiler failed on the former because "code" is
3290    also an independent variable.
3291    
3292    3. The erroneous regex a[]b caused an array overrun reference.
3293    
3294    4. A regex ending with a one-character negative class (e.g. /[^k]$/) did not
3295    fail on data ending with that character. (It was going on too far, and checking
3296    the next character, typically a binary zero.) This was specific to the
3297    optimized code for single-character negative classes.
3298    
3299    5. Added a contributed patch from the TIN world which does the following:
3300    
3301      + Add an undef for memmove, in case the the system defines a macro for it.
3302    
3303      + Add a definition of offsetof(), in case there isn't one. (I don't know
3304        the reason behind this - offsetof() is part of the ANSI standard - but
3305        it does no harm).
3306    
3307      + Reduce the ifdef's in pcre.c using macro DPRINTF, thereby eliminating
3308        most of the places where whitespace preceded '#'. I have given up and
3309        allowed the remaining 2 cases to be at the margin.
3310    
3311      + Rename some variables in pcre to eliminate shadowing. This seems very
3312        pedantic, but does no harm, of course.
3313    
3314    6. Moved the call to setjmp() into its own function, to get rid of warnings
3315    from gcc -Wall, and avoided calling it at all unless PCRE_EXTRA is used.
3316    
3317    7. Constructs such as \d{8,} were compiling into the equivalent of
3318    \d{8}\d{0,65527} instead of \d{8}\d* which didn't make much difference to the
3319    outcome, but in this particular case used more store than had been allocated,
3320    which caused the bug to be discovered because it threw up an internal error.
3321    
3322    8. The debugging code in both pcre and pcretest for outputting the compiled
3323    form of a regex was going wrong in the case of back references followed by
3324    curly-bracketed repeats.
3325    
3326    
3327  Version 1.02 12-Dec-97  Version 1.02 12-Dec-97
3328  ----------------------  ----------------------

Legend:
Removed from v.7  
changed lines
  Added in v.420

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12