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

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