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revision 71 by nigel, Sat Feb 24 21:40:24 2007 UTC revision 400 by ph10, Sat Mar 21 16:59:40 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.9 xx-xxx-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_RETURSION 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    
91    Version 7.8 05-Sep-08
92    ---------------------
93    
94    1.  Replaced UCP searching code with optimized version as implemented for Ad
95        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
96        stage table and inline lookup instead of a function, giving speed ups of 2
97        to 5 times on some simple patterns that I tested. Permission was given to
98        distribute the MultiStage2.py script that generates the tables (it's not in
99        the tarball, but is in the Subversion repository).
100    
101    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
102        scripts.
103    
104    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
105        a group with a zero qualifier. The result of the study could be incorrect,
106        or the function might crash, depending on the pattern.
107    
108    4.  Caseless matching was not working for non-ASCII characters in back
109        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
110        It now works when Unicode Property Support is available.
111    
112    5.  In pcretest, an escape such as \x{de} in the data was always generating
113        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
114        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
115        truncation.
116    
117    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
118    
119    7.  Added two (int) casts to pcregrep when printing the difference of two
120        pointers, in case they are 64-bit values.
121    
122    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
123        test 2 if it fails.
124    
125    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
126        and a #define of that name to empty if it is not externally set. This is to
127        allow users of MSVC to set it if necessary.
128    
129    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
130        the convenience functions in the pcre_get.c source file.
131    
132    11. An option change at the start of a pattern that had top-level alternatives
133        could cause overwriting and/or a crash. This command provoked a crash in
134        some environments:
135    
136          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
137    
138        This potential security problem was recorded as CVE-2008-2371.
139    
140    12. For a pattern where the match had to start at the beginning or immediately
141        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
142        pcre_dfa_exec() could read past the end of the passed subject if there was
143        no match. To help with detecting such bugs (e.g. with valgrind), I modified
144        pcretest so that it places the subject at the end of its malloc-ed buffer.
145    
146    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
147        exec() might read past the end of the data buffer in UTF-8 mode.
148    
149    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
150        the data contained the byte 0x85 as part of a UTF-8 character within its
151        first line. This applied both to normal and DFA matching.
152    
153    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
154        /^[^d]*?$/8 failed to match "abc".
155    
156    16. Added a missing copyright notice to pcrecpp_internal.h.
157    
158    17. Make it more clear in the documentation that values returned from
159        pcre_exec() in ovector are byte offsets, not character counts.
160    
161    18. Tidied a few places to stop certain compilers from issuing warnings.
162    
163    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
164        supplied by Stefan Weber. I made a further small update for 7.8 because
165        there is a change of source arrangements: the pcre_searchfuncs.c module is
166        replaced by pcre_ucd.c.
167    
168    
169    Version 7.7 07-May-08
170    ---------------------
171    
172    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
173        a string to a long long, pretend we don't even have a long long." This is
174        done by checking for the strtoq, strtoll, and _strtoi64 functions.
175    
176    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
177        pre-7.6 versions, which defined a global no_arg variable instead of putting
178        it in the RE class. (See also #8 below.)
179    
180    3.  Remove a line of dead code, identified by coverity and reported by Nuno
181        Lopes.
182    
183    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
184    
185        (1) The include/exclude patterns were being applied to the whole pathnames
186            of files, instead of just to the final components.
187    
188        (2) If there was more than one level of directory, the subdirectories were
189            skipped unless they satisfied the include/exclude conditions. This is
190            inconsistent with GNU grep (and could even be seen as contrary to the
191            pcregrep specification - which I improved to make it absolutely clear).
192            The action now is always to scan all levels of directory, and just
193            apply the include/exclude patterns to regular files.
194    
195    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
196        --exclude_dir in the tests to avoid scanning .svn directories.
197    
198    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
199        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
200        doesn't support NULs in patterns.
201    
202    7.  Added some missing "const"s to declarations of static tables in
203        pcre_compile.c and pcre_dfa_exec.c.
204    
205    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
206        caused by fix #2  above. (Subsequently also a second patch to fix the
207        first patch. And a third patch - this was a messy problem.)
208    
209    9.  Applied Craig's patch to remove the use of push_back().
210    
211    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
212        matching function regexec().
213    
214    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
215        which, however, unlike Perl's \g{...}, are subroutine calls, not back
216        references. PCRE supports relative numbers with this syntax (I don't think
217        Oniguruma does).
218    
219    12. Previously, a group with a zero repeat such as (...){0} was completely
220        omitted from the compiled regex. However, this means that if the group
221        was called as a subroutine from elsewhere in the pattern, things went wrong
222        (an internal error was given). Such groups are now left in the compiled
223        pattern, with a new opcode that causes them to be skipped at execution
224        time.
225    
226    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
227        to the way PCRE behaves:
228    
229        (a) A lone ] character is dis-allowed (Perl treats it as data).
230    
231        (b) A back reference to an unmatched subpattern matches an empty string
232            (Perl fails the current match path).
233    
234        (c) A data ] in a character class must be notated as \] because if the
235            first data character in a class is ], it defines an empty class. (In
236            Perl it is not possible to have an empty class.) The empty class []
237            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
238            The negative empty class [^] matches any one character, independently
239            of the DOTALL setting.
240    
241    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
242        non-existent subpattern following a character class starting with ']' and
243        containing () gave an internal compiling error instead of "reference to
244        non-existent subpattern". Fortunately, when the pattern did exist, the
245        compiled code was correct. (When scanning forwards to check for the
246        existencd of the subpattern, it was treating the data ']' as terminating
247        the class, so got the count wrong. When actually compiling, the reference
248        was subsequently set up correctly.)
249    
250    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
251        it was being rejected as not supported by pcre_dfa_exec(), even though
252        other assertions are supported. I have made pcre_dfa_exec() support
253        (*FAIL).
254    
255    16. The implementation of 13c above involved the invention of a new opcode,
256        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
257        cannot be changed at match time, I realized I could make a small
258        improvement to matching performance by compiling OP_ALLANY instead of
259        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
260        on the OP_ANY path.
261    
262    17. Compiling pcretest on Windows with readline support failed without the
263        following two fixes: (1) Make the unistd.h include conditional on
264        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
265    
266    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
267        ncurses library to be included for pcretest when ReadLine support is
268        requested, but also to allow for it to be overridden. This patch came from
269        Daniel Bergström.
270    
271    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
272        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
273        any errors with the current Unicode tables. Thanks to Peter Kankowski for
274        spotting this.
275    
276    
277    Version 7.6 28-Jan-08
278    ---------------------
279    
280    1.  A character class containing a very large number of characters with
281        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
282        overflow.
283    
284    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
285        HAVE_LONG_LONG is not defined.
286    
287    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
288        bring them up to date and include new features. This patch includes:
289    
290        - Fixed PH's badly added libz and libbz2 support.
291        - Fixed a problem with static linking.
292        - Added pcredemo. [But later removed - see 7 below.]
293        - Fixed dftables problem and added an option.
294        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
295            HAVE_LONG_LONG.
296        - Added readline support for pcretest.
297        - Added an listing of the option settings after cmake has run.
298    
299    4.  A user submitted a patch to Makefile that makes it easy to create
300        "pcre.dll" under mingw when using Configure/Make. I added stuff to
301        Makefile.am that cause it to include this special target, without
302        affecting anything else. Note that the same mingw target plus all
303        the other distribution libraries and programs are now supported
304        when configuring with CMake (see 6 below) instead of with
305        Configure/Make.
306    
307    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
308        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
309        exported in the Windows port". It has not yet been confirmed that the patch
310        solves the problem, but it does no harm.
311    
312    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
313        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
314        with CMake, and also correct the comment about stack recursion.
315    
316    7.  Remove the automatic building of pcredemo from the ./configure system and
317        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
318        of a program that users should build themselves after PCRE is installed, so
319        building it automatically is not really right. What is more, it gave
320        trouble in some build environments.
321    
322    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
323    
324    
325    Version 7.5 10-Jan-08
326    ---------------------
327    
328    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
329        values in parens when parsing an RE using the C++ wrapper."
330    
331    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
332        Characters greater than 255 were excluded from the class instead of being
333        included.
334    
335    3.  The same bug as (2) above applied to negated POSIX classes such as
336        [:^space:].
337    
338    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
339        defined or documented. It seems to have been a typo for PCRE_STATIC, so
340        I have changed it.
341    
342    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
343        first named subpattern) and a construct such as (?&a) would reference the
344        first named subpattern whose name started with "a" (in other words, the
345        length check was missing). Both these problems are fixed. "Subpattern name
346        expected" is now given for (?&) (a zero-length name), and this patch also
347        makes it give the same error for \k'' (previously it complained that that
348        was a reference to a non-existent subpattern).
349    
350    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
351        this is right because (?- can be followed by option settings as well as by
352        digits. I have, however, made the messages clearer.
353    
354    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
355        than the number used in the conditional) now cause a compile-time error.
356        This is actually not compatible with Perl, which accepts such patterns, but
357        treats the conditional as always being FALSE (as PCRE used to), but it
358        seems to me that giving a diagnostic is better.
359    
360    8.  Change "alphameric" to the more common word "alphanumeric" in comments
361        and messages.
362    
363    9.  Fix two occurrences of "backslash" in comments that should have been
364        "backspace".
365    
366    10. Remove two redundant lines of code that can never be obeyed (their function
367        was moved elsewhere).
368    
369    11. The program that makes PCRE's Unicode character property table had a bug
370        which caused it to generate incorrect table entries for sequences of
371        characters that have the same character type, but are in different scripts.
372        It amalgamated them into a single range, with the script of the first of
373        them. In other words, some characters were in the wrong script. There were
374        thirteen such cases, affecting characters in the following ranges:
375    
376          U+002b0 - U+002c1
377          U+0060c - U+0060d
378          U+0061e - U+00612
379          U+0064b - U+0065e
380          U+0074d - U+0076d
381          U+01800 - U+01805
382          U+01d00 - U+01d77
383          U+01d9b - U+01dbf
384          U+0200b - U+0200f
385          U+030fc - U+030fe
386          U+03260 - U+0327f
387          U+0fb46 - U+0fbb1
388          U+10450 - U+1049d
389    
390    12. The -o option (show only the matching part of a line) for pcregrep was not
391        compatible with GNU grep in that, if there was more than one match in a
392        line, it showed only the first of them. It now behaves in the same way as
393        GNU grep.
394    
395    13. If the -o and -v options were combined for pcregrep, it printed a blank
396        line for every non-matching line. GNU grep prints nothing, and pcregrep now
397        does the same. The return code can be used to tell if there were any
398        non-matching lines.
399    
400    14. Added --file-offsets and --line-offsets to pcregrep.
401    
402    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
403        infinitely looping recursion. The bug was that positive lookaheads were not
404        being skipped when checking for a possible empty match (negative lookaheads
405        and both kinds of lookbehind were skipped).
406    
407    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
408        inclusion of <windows.h> to before rather than after the definition of
409        INVALID_FILE_ATTRIBUTES (patch from David Byron).
410    
411    17. Specifying a possessive quantifier with a specific limit for a Unicode
412        character property caused pcre_compile() to compile bad code, which led at
413        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
414        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
415        caused the error; without that there was no problem.
416    
417    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
418    
419    19. Added --enable-pcretest-libreadline.
420    
421    20. In pcrecpp.cc, the variable 'count' was incremented twice in
422        RE::GlobalReplace(). As a result, the number of replacements returned was
423        double what it should be. I removed one of the increments, but Craig sent a
424        later patch that removed the other one (the right fix) and added unit tests
425        that check the return values (which was not done before).
426    
427    21. Several CMake things:
428    
429        (1) Arranged that, when cmake is used on Unix, the libraries end up with
430            the names libpcre and libpcreposix, not just pcre and pcreposix.
431    
432        (2) The above change means that pcretest and pcregrep are now correctly
433            linked with the newly-built libraries, not previously installed ones.
434    
435        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
436    
437    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
438        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
439        UTF-8 newline character). The key issue is that the pattern starts .*;
440        this means that the match must be either at the beginning, or after a
441        newline. The bug was in the code for advancing after a failed match and
442        checking that the new position followed a newline. It was not taking
443        account of UTF-8 characters correctly.
444    
445    23. PCRE was behaving differently from Perl in the way it recognized POSIX
446        character classes. PCRE was not treating the sequence [:...:] as a
447        character class unless the ... were all letters. Perl, however, seems to
448        allow any characters between [: and :], though of course it rejects as
449        unknown any "names" that contain non-letters, because all the known class
450        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
451        for example, whereas PCRE did not - it did not recognize a POSIX character
452        class. This seemed a bit dangerous, so the code has been changed to be
453        closer to Perl. The behaviour is not identical to Perl, because PCRE will
454        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
455        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
456        Perl does, and where it didn't before.
457    
458    24. Rewrite so as to remove the single use of %n from pcregrep because in some
459        Windows environments %n is disabled by default.
460    
461    
462    Version 7.4 21-Sep-07
463    ---------------------
464    
465    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
466        means that a class such as [\s] counted as "explicit reference to CR or
467        LF". That isn't really right - the whole point of the change was to try to
468        help when there was an actual mention of one of the two characters. So now
469        the change happens only if \r or \n (or a literal CR or LF) character is
470        encountered.
471    
472    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
473        of both had grown to the point where there were only 3 bits left.
474        Fortunately, there was spare space in the data structure, and so I have
475        moved the internal flags into a new 16-bit field to free up more option
476        bits.
477    
478    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
479        but did not set the internal JCHANGED flag - either of these is enough to
480        control the way the "get" function works - but the PCRE_INFO_JCHANGED
481        facility is supposed to tell if (?J) was ever used, so now (?J) at the
482        start sets both bits.
483    
484    4.  Added options (at build time, compile time, exec time) to change \R from
485        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
486    
487    5.  doc/pcresyntax.html was missing from the distribution.
488    
489    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
490        compatibility, even though it is no longer used.
491    
492    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
493        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
494        windows.h file is present (where different names are used). [This was
495        reversed later after testing - see 16 below.]
496    
497    8.  Changed all #include <config.h> to #include "config.h". There were also
498        some further <pcre.h> cases that I changed to "pcre.h".
499    
500    9.  When pcregrep was used with the --colour option, it missed the line ending
501        sequence off the lines that it output.
502    
503    10. It was pointed out to me that arrays of string pointers cause lots of
504        relocations when a shared library is dynamically loaded. A technique of
505        using a single long string with a table of offsets can drastically reduce
506        these. I have refactored PCRE in four places to do this. The result is
507        dramatic:
508    
509          Originally:                          290
510          After changing UCP table:            187
511          After changing error message table:   43
512          After changing table of "verbs"       36
513          After changing table of Posix names   22
514    
515        Thanks to the folks working on Gregex for glib for this insight.
516    
517    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
518        unicode-properties was also set.
519    
520    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
521    
522    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
523        checked only for CRLF.
524    
525    14. Added casts to pcretest.c to avoid compiler warnings.
526    
527    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
528    
529    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
530        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
531        entirely. This removes changes made in 7 above.
532    
533    17. The CMake files have been updated, and there is now more information about
534        building with CMake in the NON-UNIX-USE document.
535    
536    
537    Version 7.3 28-Aug-07
538    ---------------------
539    
540     1. In the rejigging of the build system that eventually resulted in 7.1, the
541        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
542        brackets there is not right, since it causes compilers to look for an
543        installed pcre.h, not the version that is in the source that is being
544        compiled (which of course may be different). I have changed it back to:
545    
546          #include "pcre.h"
547    
548        I have a vague recollection that the change was concerned with compiling in
549        different directories, but in the new build system, that is taken care of
550        by the VPATH setting the Makefile.
551    
552     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
553        when the subject happened to end in the byte 0x85 (e.g. if the last
554        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
555        characters but of course it shouldn't be taken as a newline when it is part
556        of another character. The bug was that, for an unlimited repeat of . in
557        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
558        characters when looking for a newline.
559    
560     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
561    
562     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
563        in debug output.
564    
565     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
566        long printing in the pcrecpp unittest when running under MinGW.
567    
568     6. ESC_K was left out of the EBCDIC table.
569    
570     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
571        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
572        limit also applies to "virtual nesting" when a pattern is recursive, and in
573        this case 1000 isn't so big. I have been able to remove this limit at the
574        expense of backing off one optimization in certain circumstances. Normally,
575        when pcre_exec() would call its internal match() function recursively and
576        immediately return the result unconditionally, it uses a "tail recursion"
577        feature to save stack. However, when a subpattern that can match an empty
578        string has an unlimited repetition quantifier, it no longer makes this
579        optimization. That gives it a stack frame in which to save the data for
580        checking that an empty string has been matched. Previously this was taken
581        from the 1000-entry workspace that had been reserved. So now there is no
582        explicit limit, but more stack is used.
583    
584     8. Applied Daniel's patches to solve problems with the import/export magic
585        syntax that is required for Windows, and which was going wrong for the
586        pcreposix and pcrecpp parts of the library. These were overlooked when this
587        problem was solved for the main library.
588    
589     9. There were some crude static tests to avoid integer overflow when computing
590        the size of patterns that contain repeated groups with explicit upper
591        limits. As the maximum quantifier is 65535, the maximum group length was
592        set at 30,000 so that the product of these two numbers did not overflow a
593        32-bit integer. However, it turns out that people want to use groups that
594        are longer than 30,000 bytes (though not repeat them that many times).
595        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
596        made it possible to implement the integer overflow checks in a much more
597        dynamic way, which I have now done. The artificial limitation on group
598        length has been removed - we now have only the limit on the total length of
599        the compiled pattern, which depends on the LINK_SIZE setting.
600    
601    10. Fixed a bug in the documentation for get/copy named substring when
602        duplicate names are permitted. If none of the named substrings are set, the
603        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
604        empty string.
605    
606    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
607        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
608        because the ] is interpreted as the first data character and the
609        terminating ] is not found. PCRE has been made compatible with Perl in this
610        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
611        cause memory overwriting.
612    
613    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
614        string has been matched (to stop an infinite loop). It was not recognizing
615        a conditional subpattern that could match an empty string if that
616        subpattern was within another subpattern. For example, it looped when
617        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
618        condition was not nested. This bug has been fixed.
619    
620    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
621        past the start of the subject in the presence of bytes with the top bit
622        set, for example "\x8aBCD".
623    
624    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
625        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
626    
627    14. Optimized (?!) to (*FAIL).
628    
629    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
630        This restricts code points to be within the range 0 to 0x10FFFF, excluding
631        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
632        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
633        does: it's just the validity check that is more restrictive.
634    
635    16. Inserted checks for integer overflows during escape sequence (backslash)
636        processing, and also fixed erroneous offset values for syntax errors during
637        backslash processing.
638    
639    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
640        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
641    
642    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
643        caused an overrun.
644    
645    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
646        something other than just ASCII characters) inside a group that had an
647        unlimited repeat caused a loop at compile time (while checking to see
648        whether the group could match an empty string).
649    
650    20. Debugging a pattern containing \p or \P could cause a crash. For example,
651        [\P{Any}] did so. (Error in the code for printing property names.)
652    
653    21. An orphan \E inside a character class could cause a crash.
654    
655    22. A repeated capturing bracket such as (A)? could cause a wild memory
656        reference during compilation.
657    
658    23. There are several functions in pcre_compile() that scan along a compiled
659        expression for various reasons (e.g. to see if it's fixed length for look
660        behind). There were bugs in these functions when a repeated \p or \P was
661        present in the pattern. These operators have additional parameters compared
662        with \d, etc, and these were not being taken into account when moving along
663        the compiled data. Specifically:
664    
665        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
666            length.
667    
668        (b) An item such as \pL+ within a repeated group could cause crashes or
669            loops.
670    
671        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
672            "reference to non-existent subpattern" error.
673    
674        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
675    
676    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
677        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
678    
679    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
680    
681    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
682        character were causing crashes (broken optimization).
683    
684    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
685        \p or \P) caused a compile-time loop.
686    
687    28. More problems have arisen in unanchored patterns when CRLF is a valid line
688        break. For example, the unstudied pattern [\r\n]A does not match the string
689        "\r\nA" because change 7.0/46 below moves the current point on by two
690        characters after failing to match at the start. However, the pattern \nA
691        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
692        the same is true. There doesn't seem any very clean way out of this, but
693        what I have chosen to do makes the common cases work: PCRE now takes note
694        of whether there can be an explicit match for \r or \n anywhere in the
695        pattern, and if so, 7.0/46 no longer applies. As part of this change,
696        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
697        pattern has explicit CR or LF references.
698    
699    29. Added (*CR) etc for changing newline setting at start of pattern.
700    
701    
702    Version 7.2 19-Jun-07
703    ---------------------
704    
705     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
706        which is apparently normally available under Windows.
707    
708     2. Re-jig the pcregrep tests with different newline settings in an attempt
709        to make them independent of the local environment's newline setting.
710    
711     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
712    
713     4. Some of the "internals" tests were previously cut out when the link size
714        was not 2, because the output contained actual offsets. The recent new
715        "Z" feature of pcretest means that these can be cut out, making the tests
716        usable with all link sizes.
717    
718     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
719        stack recursion. This gives a massive performance boost under BSD, but just
720        a small improvement under Linux. However, it saves one field in the frame
721        in all cases.
722    
723     6. Added more features from the forthcoming Perl 5.10:
724    
725        (a) (?-n) (where n is a string of digits) is a relative subroutine or
726            recursion call. It refers to the nth most recently opened parentheses.
727    
728        (b) (?+n) is also a relative subroutine call; it refers to the nth next
729            to be opened parentheses.
730    
731        (c) Conditions that refer to capturing parentheses can be specified
732            relatively, for example, (?(-2)... or (?(+3)...
733    
734        (d) \K resets the start of the current match so that everything before
735            is not part of it.
736    
737        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
738    
739        (f) \g{name} is another synonym - part of Perl 5.10's unification of
740            reference syntax.
741    
742        (g) (?| introduces a group in which the numbering of parentheses in each
743            alternative starts with the same number.
744    
745        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
746    
747     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
748        PCRE_INFO_JCHANGED.
749    
750     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
751        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
752        for detecting groups that can match an empty string.
753    
754     9. A pattern with a very large number of alternatives (more than several
755        hundred) was running out of internal workspace during the pre-compile
756        phase, where pcre_compile() figures out how much memory will be needed. A
757        bit of new cunning has reduced the workspace needed for groups with
758        alternatives. The 1000-alternative test pattern now uses 12 bytes of
759        workspace instead of running out of the 4096 that are available.
760    
761    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
762    
763    11. Applied patch from Google to remove an optimization that didn't quite work.
764        The report of the bug said:
765    
766          pcrecpp::RE("a*").FullMatch("aaa") matches, while
767          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
768          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
769    
770    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
771        it matched the wrong number of bytes.
772    
773    
774    Version 7.1 24-Apr-07
775    ---------------------
776    
777     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
778        that is more "standard", making use of automake and other Autotools. There
779        is some re-arrangement of the files and adjustment of comments consequent
780        on this.
781    
782     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
783        for recursive directory scanning broke on some systems because the files
784        are not scanned in any specific order and on different systems the order
785        was different. A call to "sort" has been inserted into RunGrepTest for the
786        approprate test as a short-term fix. In the longer term there may be an
787        alternative.
788    
789     3. I had an email from Eric Raymond about problems translating some of PCRE's
790        man pages to HTML (despite the fact that I distribute HTML pages, some
791        people do their own conversions for various reasons). The problems
792        concerned the use of low-level troff macros .br and .in. I have therefore
793        removed all such uses from the man pages (some were redundant, some could
794        be replaced by .nf/.fi pairs). The 132html script that I use to generate
795        HTML has been updated to handle .nf/.fi and to complain if it encounters
796        .br or .in.
797    
798     4. Updated comments in configure.ac that get placed in config.h.in and also
799        arranged for config.h to be included in the distribution, with the name
800        config.h.generic, for the benefit of those who have to compile without
801        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
802    
803     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
804        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
805        makevp.bat for the current PCRE, using the additional files
806        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
807    
808     6. A Windows user reported a minor discrepancy with test 2, which turned out
809        to be caused by a trailing space on an input line that had got lost in his
810        copy. The trailing space was an accident, so I've just removed it.
811    
812     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
813        that is needed.
814    
815     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
816        as "const" (a) because they are and (b) because it helps the PHP
817        maintainers who have recently made a script to detect big data structures
818        in the php code that should be moved to the .rodata section. I remembered
819        to update Builducptable as well, so it won't revert if ucptable.h is ever
820        re-created.
821    
822     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
823        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
824        order to be able to cut out the UTF-8 tables in the latter when UTF-8
825        support is not required. This saves 1.5-2K of code, which is important in
826        some applications.
827    
828        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
829        so as not to refer to the tables, even though these functions will never be
830        called when UTF-8 support is disabled. Otherwise there are problems with a
831        shared library.
832    
833    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
834    
835        (a) It was defining its arguments as char * instead of void *.
836    
837        (b) It was assuming that all moves were upwards in memory; this was true
838            a long time ago when I wrote it, but is no longer the case.
839    
840        The emulated memove() is provided for those environments that have neither
841        memmove() nor bcopy(). I didn't think anyone used it these days, but that
842        is clearly not the case, as these two bugs were recently reported.
843    
844    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
845        and Detrail to create the HTML documentation, the .txt form of the man
846        pages, and it removes trailing spaces from listed files. It also creates
847        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
848        case, it wraps all the #defines with #ifndefs. This script should be run
849        before "make dist".
850    
851    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
852        with Unicode property support.
853    
854        (a) For a maximizing quantifier, if the two different cases of the
855            character were of different lengths in their UTF-8 codings (there are
856            some cases like this - I found 11), and the matching function had to
857            back up over a mixture of the two cases, it incorrectly assumed they
858            were both the same length.
859    
860        (b) When PCRE was configured to use the heap rather than the stack for
861            recursion during matching, it was not correctly preserving the data for
862            the other case of a UTF-8 character when checking ahead for a match
863            while processing a minimizing repeat. If the check also involved
864            matching a wide character, but failed, corruption could cause an
865            erroneous result when trying to check for a repeat of the original
866            character.
867    
868    13. Some tidying changes to the testing mechanism:
869    
870        (a) The RunTest script now detects the internal link size and whether there
871            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
872            values substituted by "configure". (The RunGrepTest script already did
873            this for UTF-8.) The configure.ac script no longer substitutes the
874            relevant variables.
875    
876        (b) The debugging options /B and /D in pcretest show the compiled bytecode
877            with length and offset values. This means that the output is different
878            for different internal link sizes. Test 2 is skipped for link sizes
879            other than 2 because of this, bypassing the problem. Unfortunately,
880            there was also a test in test 3 (the locale tests) that used /B and
881            failed for link sizes other than 2. Rather than cut the whole test out,
882            I have added a new /Z option to pcretest that replaces the length and
883            offset values with spaces. This is now used to make test 3 independent
884            of link size. (Test 2 will be tidied up later.)
885    
886    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
887        segmentation fault instead of returning the appropriate error message.
888    
889    15. In multiline mode when the newline sequence was set to "any", the pattern
890        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
891        This doesn't seem right; it now treats the CRLF combination as the line
892        ending, and so does not match in that case. It's only a pattern such as ^$
893        that would hit this one: something like ^ABC$ would have failed after \r
894        and then tried again after \r\n.
895    
896    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
897        in an attempt to make files that differ only in their line terminators
898        compare equal. This works on Linux.
899    
900    17. Under certain error circumstances pcregrep might try to free random memory
901        as it exited. This is now fixed, thanks to valgrind.
902    
903    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
904        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
905        was because its rules for how to advance for /g after matching an empty
906        string at the end of a line did not allow for this case. They now check for
907        it specially.
908    
909    20. pcretest is supposed to handle patterns and data of any length, by
910        extending its buffers when necessary. It was getting this wrong when the
911        buffer for a data line had to be extended.
912    
913    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
914        CRLF as a newline sequence.
915    
916    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
917        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
918        I have nevertheless tidied it up.
919    
920    23. Added some casts to kill warnings from HP-UX ia64 compiler.
921    
922    24. Added a man page for pcre-config.
923    
924    
925    Version 7.0 19-Dec-06
926    ---------------------
927    
928     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
929        moving to gcc 4.1.1.
930    
931     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
932        sys/time.h, which is documented as needed for this function. It doesn't
933        seem to matter on Linux, but it showed up on some releases of OS X.
934    
935     3. It seems that there are systems where bytes whose values are greater than
936        127 match isprint() in the "C" locale. The "C" locale should be the
937        default when a C program starts up. In most systems, only ASCII printing
938        characters match isprint(). This difference caused the output from pcretest
939        to vary, making some of the tests fail. I have changed pcretest so that:
940    
941        (a) When it is outputting text in the compiled version of a pattern, bytes
942            other than 32-126 are always shown as hex escapes.
943    
944        (b) When it is outputting text that is a matched part of a subject string,
945            it does the same, unless a different locale has been set for the match
946            (using the /L modifier). In this case, it uses isprint() to decide.
947    
948     4. Fixed a major bug that caused incorrect computation of the amount of memory
949        required for a compiled pattern when options that changed within the
950        pattern affected the logic of the preliminary scan that determines the
951        length. The relevant options are -x, and -i in UTF-8 mode. The result was
952        that the computed length was too small. The symptoms of this bug were
953        either the PCRE error "internal error: code overflow" from pcre_compile(),
954        or a glibc crash with a message such as "pcretest: free(): invalid next
955        size (fast)". Examples of patterns that provoked this bug (shown in
956        pcretest format) are:
957    
958          /(?-x: )/x
959          /(?x)(?-x: \s*#\s*)/
960          /((?i)[\x{c0}])/8
961          /(?i:[\x{c0}])/8
962    
963        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
964        is now done differently.
965    
966     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
967        wrapper classes; (b) implement a new function in the C++ scanner that is
968        more efficient than the old way of doing things because it avoids levels of
969        recursion in the regex matching; (c) add a paragraph to the documentation
970        for the FullMatch() function.
971    
972     6. The escape sequence \n was being treated as whatever was defined as
973        "newline". Not only was this contrary to the documentation, which states
974        that \n is character 10 (hex 0A), but it also went horribly wrong when
975        "newline" was defined as CRLF. This has been fixed.
976    
977     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
978        was being set to -1 for the "end of line" case (supposedly a value that no
979        character can have). Though this value is never used (the check for end of
980        line is "zero bytes in current character"), it caused compiler complaints.
981        I've changed it to 0xffffffff.
982    
983     8. In pcre_version.c, the version string was being built by a sequence of
984        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
985        string (as it is for production releases) called a macro with an empty
986        argument. The C standard says the result of this is undefined. The gcc
987        compiler treats it as an empty string (which was what was wanted) but it is
988        reported that Visual C gives an error. The source has been hacked around to
989        avoid this problem.
990    
991     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
992        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
993        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
994        of them did).
995    
996    10. Originally, pcretest opened its input and output without "b"; then I was
997        told that "b" was needed in some environments, so it was added for release
998        5.0 to both the input and output. (It makes no difference on Unix-like
999        systems.) Later I was told that it is wrong for the input on Windows. I've
1000        now abstracted the modes into two macros, to make it easier to fiddle with
1001        them, and removed "b" from the input mode under Windows.
1002    
1003    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1004    
1005    12. Added -help and --help to pcretest as an official way of being reminded
1006        of the options.
1007    
1008    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1009        and pcrecpp.cc because they annoy compilers at high warning levels.
1010    
1011    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1012    
1013    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1014        scripts are not C programs :-) and which was not noticed because it works
1015        on Linux.
1016    
1017    16. pcretest is supposed to handle any length of pattern and data line (as one
1018        line or as a continued sequence of lines) by extending its input buffer if
1019        necessary. This feature was broken for very long pattern lines, leading to
1020        a string of junk being passed to pcre_compile() if the pattern was longer
1021        than about 50K.
1022    
1023    17. I have done a major re-factoring of the way pcre_compile() computes the
1024        amount of memory needed for a compiled pattern. Previously, there was code
1025        that made a preliminary scan of the pattern in order to do this. That was
1026        OK when PCRE was new, but as the facilities have expanded, it has become
1027        harder and harder to keep it in step with the real compile phase, and there
1028        have been a number of bugs (see for example, 4 above). I have now found a
1029        cunning way of running the real compile function in a "fake" mode that
1030        enables it to compute how much memory it would need, while actually only
1031        ever using a few hundred bytes of working memory and without too many
1032        tests of the mode. This should make future maintenance and development
1033        easier. A side effect of this work is that the limit of 200 on the nesting
1034        depth of parentheses has been removed (though this was never a serious
1035        limitation, I suspect). However, there is a downside: pcre_compile() now
1036        runs more slowly than before (30% or more, depending on the pattern). I
1037        hope this isn't a big issue. There is no effect on runtime performance.
1038    
1039    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1040        newline (only possible for the last line of a file) and it was a
1041        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1042    
1043    19. Added additional timing features to pcretest. (1) The -tm option now times
1044        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1045        separate command line item, by a number that specifies the number of
1046        repeats to use when timing. The default is 50000; this gives better
1047        precision, but takes uncomfortably long for very large patterns.
1048    
1049    20. Extended pcre_study() to be more clever in cases where a branch of a
1050        subpattern has no definite first character. For example, (a*|b*)[cd] would
1051        previously give no result from pcre_study(). Now it recognizes that the
1052        first character must be a, b, c, or d.
1053    
1054    21. There was an incorrect error "recursive call could loop indefinitely" if
1055        a subpattern (or the entire pattern) that was being tested for matching an
1056        empty string contained only one non-empty item after a nested subpattern.
1057        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1058        incorrectly, because the \d was being skipped in the check.
1059    
1060    22. The pcretest program now has a new pattern option /B and a command line
1061        option -b, which is equivalent to adding /B to every pattern. This causes
1062        it to show the compiled bytecode, without the additional information that
1063        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1064        is the same as /B/I).
1065    
1066    23. A new optimization is now able automatically to treat some sequences such
1067        as a*b as a*+b. More specifically, if something simple (such as a character
1068        or a simple class like \d) has an unlimited quantifier, and is followed by
1069        something that cannot possibly match the quantified thing, the quantifier
1070        is automatically "possessified".
1071    
1072    24. A recursive reference to a subpattern whose number was greater than 39
1073        went wrong under certain circumstances in UTF-8 mode. This bug could also
1074        have affected the operation of pcre_study().
1075    
1076    25. Realized that a little bit of performance could be had by replacing
1077        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1078    
1079    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1080    
1081    27. Possessive quantifiers such as a++ were previously implemented by turning
1082        them into atomic groups such as ($>a+). Now they have their own opcodes,
1083        which improves performance. This includes the automatically created ones
1084        from 23 above.
1085    
1086    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1087        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1088        the first matched character to be a colon. This applied both to named and
1089        numbered groups.
1090    
1091    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1092    
1093    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1094        building PCRE on Windows easier, so I have included it in the distribution.
1095    
1096    31. There is now a check in pcretest against a ridiculously large number being
1097        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1098        loop, the loop is abandoned.
1099    
1100    32. Forward references to subpatterns in conditions such as (?(2)...) where
1101        subpattern 2 is defined later cause pcre_compile() to search forwards in
1102        the pattern for the relevant set of parentheses. This search went wrong
1103        when there were unescaped parentheses in a character class, parentheses
1104        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1105    
1106    33. "Subroutine" calls and backreferences were previously restricted to
1107        referencing subpatterns earlier in the regex. This restriction has now
1108        been removed.
1109    
1110    34. Added a number of extra features that are going to be in Perl 5.10. On the
1111        whole, these are just syntactic alternatives for features that PCRE had
1112        previously implemented using the Python syntax or my own invention. The
1113        other formats are all retained for compatibility.
1114    
1115        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1116            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1117            also .NET compatible.
1118    
1119        (b) A recursion or subroutine call to a named group can now be defined as
1120            (?&name) as well as (?P>name).
1121    
1122        (c) A backreference to a named group can now be defined as \k<name> or
1123            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1124            5.10, are also .NET compatible.
1125    
1126        (d) A conditional reference to a named group can now use the syntax
1127            (?(<name>) or (?('name') as well as (?(name).
1128    
1129        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1130            groups (named and numbered) that are never evaluated inline, but can be
1131            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1132            is always false. There may be only one alternative in such a group.
1133    
1134        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1135            as the simple (?(R). The condition is true only if the most recent
1136            recursion is that of the given number or name. It does not search out
1137            through the entire recursion stack.
1138    
1139        (g) The escape \gN or \g{N} has been added, where N is a positive or
1140            negative number, specifying an absolute or relative reference.
1141    
1142    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1143        some "unreachable code" warnings.
1144    
1145    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1146        things, this adds five new scripts.
1147    
1148    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1149        There were also incompatibilities regarding the handling of \Q..\E inside
1150        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1151        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1152    
1153    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1154        matches an empty string, and forcibly breaks the loop. There were bugs in
1155        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1156        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1157        separate and independent bugs (that affected different cases) have been
1158        fixed.
1159    
1160    39. Refactored the code to abolish the use of different opcodes for small
1161        capturing bracket numbers. This is a tidy that I avoided doing when I
1162        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1163        The new approach is not only tidier, it makes it possible to reduce the
1164        memory needed to fix the previous bug (38).
1165    
1166    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1167        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1168        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1169        mode.
1170    
1171    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1172        report.
1173    
1174    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1175        copy construction and assignment in the C++ wrapper.
1176    
1177    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1178        couple of bugs that could have given wrong results in the "--newline=crlf"
1179        case.
1180    
1181    44. Added a number of casts and did some reorganization of signed/unsigned int
1182        variables following suggestions from Dair Grant. Also renamed the variable
1183        "this" as "item" because it is a C++ keyword.
1184    
1185    45. Arranged for dftables to add
1186    
1187          #include "pcre_internal.h"
1188    
1189        to pcre_chartables.c because without it, gcc 4.x may remove the array
1190        definition from the final binary if PCRE is built into a static library and
1191        dead code stripping is activated.
1192    
1193    46. For an unanchored pattern, if a match attempt fails at the start of a
1194        newline sequence, and the newline setting is CRLF or ANY, and the next two
1195        characters are CRLF, advance by two characters instead of one.
1196    
1197    
1198    Version 6.7 04-Jul-06
1199    ---------------------
1200    
1201     1. In order to handle tests when input lines are enormously long, pcretest has
1202        been re-factored so that it automatically extends its buffers when
1203        necessary. The code is crude, but this _is_ just a test program. The
1204        default size has been increased from 32K to 50K.
1205    
1206     2. The code in pcre_study() was using the value of the re argument before
1207        testing it for NULL. (Of course, in any sensible call of the function, it
1208        won't be NULL.)
1209    
1210     3. The memmove() emulation function in pcre_internal.h, which is used on
1211        systems that lack both memmove() and bcopy() - that is, hardly ever -
1212        was missing a "static" storage class specifier.
1213    
1214     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1215        containing an extended class (one that cannot be represented by a bitmap
1216        because it contains high-valued characters or Unicode property items, e.g.
1217        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1218        pattern, but PCRE should not loop if you do not (it no longer does).
1219        [Detail: two cases were found: (a) a repeated subpattern containing an
1220        extended class; (b) a recursive reference to a subpattern that followed a
1221        previous extended class. It wasn't skipping over the extended class
1222        correctly when UTF-8 mode was not set.]
1223    
1224     5. A negated single-character class was not being recognized as fixed-length
1225        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1226        compile error "lookbehind assertion is not fixed length".
1227    
1228     6. The RunPerlTest auxiliary script was showing an unexpected difference
1229        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1230        write a Perl script that can interpret lines of an input file either as
1231        byte characters or as UTF-8, which is what "perltest" was being required to
1232        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1233        can't do is switch easily at run time between having the "use utf8;" pragma
1234        or not. In the end, I fudged it by using the RunPerlTest script to insert
1235        "use utf8;" explicitly for the UTF-8 tests.
1236    
1237     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1238        the end of the subject string, contrary to the documentation and to what
1239        Perl does. This was true of both matching functions. Now it matches only at
1240        the start of the subject and immediately after *internal* newlines.
1241    
1242     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1243        a pointer to an int instead of a pointer to an unsigned long int. This
1244        caused problems on 64-bit systems.
1245    
1246     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1247        instance of the 'standard' template library not being so standard".
1248    
1249    10. There was no check on the number of named subpatterns nor the maximum
1250        length of a subpattern name. The product of these values is used to compute
1251        the size of the memory block for a compiled pattern. By supplying a very
1252        long subpattern name and a large number of named subpatterns, the size
1253        computation could be caused to overflow. This is now prevented by limiting
1254        the length of names to 32 characters, and the number of named subpatterns
1255        to 10,000.
1256    
1257    11. Subpatterns that are repeated with specific counts have to be replicated in
1258        the compiled pattern. The size of memory for this was computed from the
1259        length of the subpattern and the repeat count. The latter is limited to
1260        65535, but there was no limit on the former, meaning that integer overflow
1261        could in principle occur. The compiled length of a repeated subpattern is
1262        now limited to 30,000 bytes in order to prevent this.
1263    
1264    12. Added the optional facility to have named substrings with the same name.
1265    
1266    13. Added the ability to use a named substring as a condition, using the
1267        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1268        are numbers (not recommended). Forward references are permitted.
1269    
1270    14. Added forward references in named backreferences (if you see what I mean).
1271    
1272    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1273        pattern could run off the end of the subject. For example, the pattern
1274        "(?s)(.{1,5})"8 did this with the subject "ab".
1275    
1276    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1277        PCRE_CASELESS was set when matching characters that were quantified with ?
1278        or *.
1279    
1280    17. A character class other than a single negated character that had a minimum
1281        but no maximum quantifier - for example [ab]{6,} - was not handled
1282        correctly by pce_dfa_exec(). It would match only one character.
1283    
1284    18. A valid (though odd) pattern that looked like a POSIX character
1285        class but used an invalid character after [ (for example [[,abc,]]) caused
1286        pcre_compile() to give the error "Failed: internal error: code overflow" or
1287        in some cases to crash with a glibc free() error. This could even happen if
1288        the pattern terminated after [[ but there just happened to be a sequence of
1289        letters, a binary zero, and a closing ] in the memory that followed.
1290    
1291    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1292        over the years. Originally (before any Unicode support), just the bottom 8
1293        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1294        output from "man perlunicode" includes this:
1295    
1296          The regular expression compiler produces polymorphic opcodes.  That
1297          is, the pattern adapts to the data and automatically switches to
1298          the Unicode character scheme when presented with Unicode data--or
1299          instead uses a traditional byte scheme when presented with byte
1300          data.
1301    
1302        Sadly, a wide octal escape does not cause a switch, and in a string with
1303        no other multibyte characters, these octal escapes are treated as before.
1304        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1305        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1306        Unicode string.
1307    
1308        I have not perpetrated such confusion in PCRE. Up till now, it took just
1309        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1310        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1311        translate to the appropriate multibyte character.
1312    
1313    29. Applied some refactoring to reduce the number of warnings from Microsoft
1314        and Borland compilers. This has included removing the fudge introduced
1315        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1316        a warning about an unused variable.
1317    
1318    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1319        characters since release 4.0, because Perl (from release 5.004) does not.
1320        [Or at least, is documented not to: some releases seem to be in conflict
1321        with the documentation.] However, when a pattern was studied with
1322        pcre_study() and all its branches started with \s, PCRE still included VT
1323        as a possible starting character. Of course, this did no harm; it just
1324        caused an unnecessary match attempt.
1325    
1326    22. Removed a now-redundant internal flag bit that recorded the fact that case
1327        dependency changed within the pattern. This was once needed for "required
1328        byte" processing, but is no longer used. This recovers a now-scarce options
1329        bit. Also moved the least significant internal flag bit to the most-
1330        significant bit of the word, which was not previously used (hangover from
1331        the days when it was an int rather than a uint) to free up another bit for
1332        the future.
1333    
1334    23. Added support for CRLF line endings as well as CR and LF. As well as the
1335        default being selectable at build time, it can now be changed at runtime
1336        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1337        specify that it is scanning data with non-default line endings.
1338    
1339    24. Changed the definition of CXXLINK to make it agree with the definition of
1340        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1341    
1342    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1343        recursions. This makes a big different to stack usage for some patterns.
1344    
1345    26. If a subpattern containing a named recursion or subroutine reference such
1346        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1347        the space required for the compiled pattern went wrong and gave too small a
1348        value. Depending on the environment, this could lead to "Failed: internal
1349        error: code overflow at offset 49" or "glibc detected double free or
1350        corruption" errors.
1351    
1352    27. Applied patches from Google (a) to support the new newline modes and (b) to
1353        advance over multibyte UTF-8 characters in GlobalReplace.
1354    
1355    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1356        difference for some implementation of PCRE in some Windows version.
1357    
1358    29. Added some extra testing facilities to pcretest:
1359    
1360        \q<number>   in a data line sets the "match limit" value
1361        \Q<number>   in a data line sets the "match recursion limt" value
1362        -S <number>  sets the stack size, where <number> is in megabytes
1363    
1364        The -S option isn't available for Windows.
1365    
1366    
1367    Version 6.6 06-Feb-06
1368    ---------------------
1369    
1370     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1371        in pcreposix.h. I have copied the definition from pcre.h.
1372    
1373     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1374        because pcre.h is no longer a built file.
1375    
1376     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1377        not normally included in the compiled code.
1378    
1379    
1380    Version 6.5 01-Feb-06
1381    ---------------------
1382    
1383     1. When using the partial match feature with pcre_dfa_exec(), it was not
1384        anchoring the second and subsequent partial matches at the new starting
1385        point. This could lead to incorrect results. For example, with the pattern
1386        /1234/, partially matching against "123" and then "a4" gave a match.
1387    
1388     2. Changes to pcregrep:
1389    
1390        (a) All non-match returns from pcre_exec() were being treated as failures
1391            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1392            error message is output. Some extra information is given for the
1393            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1394            probably the only errors that are likely to be caused by users (by
1395            specifying a regex that has nested indefinite repeats, for instance).
1396            If there are more than 20 of these errors, pcregrep is abandoned.
1397    
1398        (b) A binary zero was treated as data while matching, but terminated the
1399            output line if it was written out. This has been fixed: binary zeroes
1400            are now no different to any other data bytes.
1401    
1402        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1403            used to set a locale for matching. The --locale=xxxx long option has
1404            been added (no short equivalent) to specify a locale explicitly on the
1405            pcregrep command, overriding the environment variables.
1406    
1407        (d) When -B was used with -n, some line numbers in the output were one less
1408            than they should have been.
1409    
1410        (e) Added the -o (--only-matching) option.
1411    
1412        (f) If -A or -C was used with -c (count only), some lines of context were
1413            accidentally printed for the final match.
1414    
1415        (g) Added the -H (--with-filename) option.
1416    
1417        (h) The combination of options -rh failed to suppress file names for files
1418            that were found from directory arguments.
1419    
1420        (i) Added the -D (--devices) and -d (--directories) options.
1421    
1422        (j) Added the -F (--fixed-strings) option.
1423    
1424        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1425    
1426        (l) Added the --colo(u)r option.
1427    
1428        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1429            is not present by default.
1430    
1431     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1432        items such as (?R) or (?1), when the recursion could match a number of
1433        alternatives. If it matched one of the alternatives, but subsequently,
1434        outside the recursion, there was a failure, the code tried to back up into
1435        the recursion. However, because of the way PCRE is implemented, this is not
1436        possible, and the result was an incorrect result from the match.
1437    
1438        In order to prevent this happening, the specification of recursion has
1439        been changed so that all such subpatterns are automatically treated as
1440        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1441    
1442     4. I had overlooked the fact that, in some locales, there are characters for
1443        which isalpha() is true but neither isupper() nor islower() are true. In
1444        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1445        and ordfeminine) are like this. This affected the treatment of \w and \W
1446        when they appeared in character classes, but not when they appeared outside
1447        a character class. The bit map for "word" characters is now created
1448        separately from the results of isalnum() instead of just taking it from the
1449        upper, lower, and digit maps. (Plus the underscore character, of course.)
1450    
1451     5. The above bug also affected the handling of POSIX character classes such as
1452        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1453        permanent tables. Instead, the bit maps for such a class were previously
1454        created as the appropriate unions of the upper, lower, and digit bitmaps.
1455        Now they are created by subtraction from the [[:word:]] class, which has
1456        its own bitmap.
1457    
1458     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1459        It is created by subtracting the vertical space characters (\x09, \x0a,
1460        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1461        subtraction was done in the overall bitmap for a character class, meaning
1462        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1463        be recognized. This bug has been fixed.
1464    
1465     7. Patches from the folks at Google:
1466    
1467          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1468          real life, but is still worth protecting against".
1469    
1470          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1471          regular expressions".
1472    
1473          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1474          have it.
1475    
1476          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1477          "configure" and the latter not, in order to fix a problem somebody had
1478          with compiling the Arg class on HP-UX.
1479    
1480          (e) Improve the error-handling of the C++ wrapper a little bit.
1481    
1482          (f) New tests for checking recursion limiting.
1483    
1484     8. The pcre_memmove() function, which is used only if the environment does not
1485        have a standard memmove() function (and is therefore rarely compiled),
1486        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1487        returning a result (though PCRE never actually uses the result).
1488    
1489     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1490        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1491        returned instead of calling malloc() with an overflowing number that would
1492        most likely cause subsequent chaos.
1493    
1494    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1495    
1496    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1497        with this option is matched, the nmatch and pmatch options of regexec() are
1498        ignored.
1499    
1500    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1501        provided in case anyone wants to the the POSIX interface with UTF-8
1502        strings.
1503    
1504    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1505        C++ linking (needed for some HP-UX environments).
1506    
1507    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1508        (unused parameter) and in the pcre_printint() function (omitted "default"
1509        switch label when the default is to do nothing).
1510    
1511    15. Added some code to make it possible, when PCRE is compiled as a C++
1512        library, to replace subject pointers for pcre_exec() with a smart pointer
1513        class, thus making it possible to process discontinuous strings.
1514    
1515    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1516        much the same function. They were added by different people who were trying
1517        to make PCRE easy to compile on non-Unix systems. It has been suggested
1518        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1519        for compiling on Windows systems. I have therefore replaced it with
1520        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1521        defaults to "extern" for C or "extern C" for C++, which works fine on
1522        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1523        SCOPE with something explicit in config.h. In addition:
1524    
1525        (a) pcreposix.h still had just "extern" instead of either of these macros;
1526            I have replaced it with PCRE_DATA_SCOPE.
1527    
1528        (b) Functions such as _pcre_xclass(), which are internal to the library,
1529            but external in the C sense, all had PCRE_EXPORT in their definitions.
1530            This is apparently wrong for the Windows case, so I have removed it.
1531            (It makes no difference on Unix-like systems.)
1532    
1533    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1534        of recursive calls to match(). This is different to MATCH_LIMIT because
1535        that limits the total number of calls to match(), not all of which increase
1536        the depth of recursion. Limiting the recursion depth limits the amount of
1537        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1538        when PCRE is compiled, and changed at run time. A patch from Google adds
1539        this functionality to the C++ interface.
1540    
1541    18. Changes to the handling of Unicode character properties:
1542    
1543        (a) Updated the table to Unicode 4.1.0.
1544    
1545        (b) Recognize characters that are not in the table as "Cn" (undefined).
1546    
1547        (c) I revised the way the table is implemented to a much improved format
1548            which includes recognition of ranges. It now supports the ranges that
1549            are defined in UnicodeData.txt, and it also amalgamates other
1550            characters into ranges. This has reduced the number of entries in the
1551            table from around 16,000 to around 3,000, thus reducing its size
1552            considerably. I realized I did not need to use a tree structure after
1553            all - a binary chop search is just as efficient. Having reduced the
1554            number of entries, I extended their size from 6 bytes to 8 bytes to
1555            allow for more data.
1556    
1557        (d) Added support for Unicode script names via properties such as \p{Han}.
1558    
1559    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1560        matching that character.
1561    
1562    20. When matching a repeated Unicode property with a minimum greater than zero,
1563        (for example \pL{2,}), PCRE could look past the end of the subject if it
1564        reached it while seeking the minimum number of characters. This could
1565        happen only if some of the characters were more than one byte long, because
1566        there is a check for at least the minimum number of bytes.
1567    
1568    21. Refactored the implementation of \p and \P so as to be more general, to
1569        allow for more different types of property in future. This has changed the
1570        compiled form incompatibly. Anybody with saved compiled patterns that use
1571        \p or \P will have to recompile them.
1572    
1573    22. Added "Any" and "L&" to the supported property types.
1574    
1575    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1576        but give a compile time error if the value is greater than 0xff.
1577    
1578    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1579        accidentally not being installed or uninstalled.
1580    
1581    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1582        made were to insert the current release number. This seemed silly, because
1583        it made things harder for people building PCRE on systems that don't run
1584        "configure". I have turned pcre.h into a distributed file, no longer built
1585        by "configure", with the version identification directly included. There is
1586        no longer a pcre.h.in file.
1587    
1588        However, this change necessitated a change to the pcre-config script as
1589        well. It is built from pcre-config.in, and one of the substitutions was the
1590        release number. I have updated configure.ac so that ./configure now finds
1591        the release number by grepping pcre.h.
1592    
1593    26. Added the ability to run the tests under valgrind.
1594    
1595    
1596    Version 6.4 05-Sep-05
1597    ---------------------
1598    
1599     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1600        "--" to be printed when multiple files were scanned, even when none of the
1601        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1602        consider it to be a bug, and have restored the previous behaviour.
1603    
1604     2. A couple of code tidies to get rid of compiler warnings.
1605    
1606     3. The pcretest program used to cheat by referring to symbols in the library
1607        whose names begin with _pcre_. These are internal symbols that are not
1608        really supposed to be visible externally, and in some environments it is
1609        possible to suppress them. The cheating is now confined to including
1610        certain files from the library's source, which is a bit cleaner.
1611    
1612     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1613        file's purpose clearer.
1614    
1615     5. Reorganized pcre_ucp_findchar().
1616    
1617    
1618    Version 6.3 15-Aug-05
1619    ---------------------
1620    
1621     1. The file libpcre.pc.in did not have general read permission in the tarball.
1622    
1623     2. There were some problems when building without C++ support:
1624    
1625        (a) If C++ support was not built, "make install" and "make test" still
1626            tried to test it.
1627    
1628        (b) There were problems when the value of CXX was explicitly set. Some
1629            changes have been made to try to fix these, and ...
1630    
1631        (c) --disable-cpp can now be used to explicitly disable C++ support.
1632    
1633        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1634            backslash in a target when C++ was disabled. This confuses some
1635            versions of "make", apparently. Using an intermediate variable solves
1636            this. (Same for CPP_LOBJ.)
1637    
1638     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1639        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1640        necessary on certain architectures.
1641    
1642     4. Added a setting of -export-symbols-regex to the link command to remove
1643        those symbols that are exported in the C sense, but actually are local
1644        within the library, and not documented. Their names all begin with
1645        "_pcre_". This is not a perfect job, because (a) we have to except some
1646        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1647        available (and never for static libraries). I have made a note to try to
1648        find a way round (a) in the future.
1649    
1650    
1651    Version 6.2 01-Aug-05
1652    ---------------------
1653    
1654     1. There was no test for integer overflow of quantifier values. A construction
1655        such as {1111111111111111} would give undefined results. What is worse, if
1656        a minimum quantifier for a parenthesized subpattern overflowed and became
1657        negative, the calculation of the memory size went wrong. This could have
1658        led to memory overwriting.
1659    
1660     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1661    
1662     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1663        operating environments where this matters.
1664    
1665     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1666        PCRE options from within the C++ wrapper.
1667    
1668     5. Named capturing subpatterns were not being correctly counted when a pattern
1669        was compiled. This caused two problems: (a) If there were more than 100
1670        such subpatterns, the calculation of the memory needed for the whole
1671        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1672        back references of the form \12, where the number was greater than 9, were
1673        not recognized as back references, even though there were sufficient
1674        previous subpatterns.
1675    
1676     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1677        versions of gcc, e.g. 2.95.4.
1678    
1679    
1680    Version 6.1 21-Jun-05
1681    ---------------------
1682    
1683     1. There was one reference to the variable "posix" in pcretest.c that was not
1684        surrounded by "#if !defined NOPOSIX".
1685    
1686     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1687        the cross-check on the old pcre_info() function, for the benefit of the
1688        cut-down version of PCRE that is currently imported into Exim.
1689    
1690     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1691        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1692        patterns that start (?i) but I don't think that matters. The use of (?i) is
1693        just an example; this all applies to the other options as well.
1694    
1695     4. Since libtool seems to echo the compile commands it is issuing, the output
1696        from "make" can be reduced a bit by putting "@" in front of each libtool
1697        compile command.
1698    
1699     5. Patch from the folks at Google for configure.in to be a bit more thorough
1700        in checking for a suitable C++ installation before trying to compile the
1701        C++ stuff. This should fix a reported problem when a compiler was present,
1702        but no suitable headers.
1703    
1704     6. The man pages all had just "PCRE" as their title. I have changed them to
1705        be the relevant file name. I have also arranged that these names are
1706        retained in the file doc/pcre.txt, which is a concatenation in text format
1707        of all the man pages except the little individual ones for each function.
1708    
1709     7. The NON-UNIX-USE file had not been updated for the different set of source
1710        files that come with release 6. I also added a few comments about the C++
1711        wrapper.
1712    
1713    
1714    Version 6.0 07-Jun-05
1715    ---------------------
1716    
1717     1. Some minor internal re-organization to help with my DFA experiments.
1718    
1719     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1720        didn't matter for the library itself when fully configured, but did matter
1721        when compiling without UCP support, or within Exim, where the ucp files are
1722        not imported.
1723    
1724     3. Refactoring of the library code to split up the various functions into
1725        different source modules. The addition of the new DFA matching code (see
1726        below) to a single monolithic source would have made it really too
1727        unwieldy, quite apart from causing all the code to be include in a
1728        statically linked application, when only some functions are used. This is
1729        relevant even without the DFA addition now that patterns can be compiled in
1730        one application and matched in another.
1731    
1732        The downside of splitting up is that there have to be some external
1733        functions and data tables that are used internally in different modules of
1734        the library but which are not part of the API. These have all had their
1735        names changed to start with "_pcre_" so that they are unlikely to clash
1736        with other external names.
1737    
1738     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1739        a different (DFA) algorithm. Although it is slower than the original
1740        function, it does have some advantages for certain types of matching
1741        problem.
1742    
1743     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1744        including restarting after a partial match.
1745    
1746     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1747        defined when compiling for Windows was sent to me. I have put it into the
1748        code, though I have no means of testing or verifying it.
1749    
1750     7. Added the pcre_refcount() auxiliary function.
1751    
1752     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1753        match before or at the first newline in the subject string. In pcretest,
1754        the /f option on a pattern can be used to set this.
1755    
1756     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1757        would behave wrongly. This has been present in PCRE since release 4.0.
1758    
1759    10. A number of changes to the pcregrep command:
1760    
1761        (a) Refactored how -x works; insert ^(...)$ instead of setting
1762            PCRE_ANCHORED and checking the length, in preparation for adding
1763            something similar for -w.
1764    
1765        (b) Added the -w (match as a word) option.
1766    
1767        (c) Refactored the way lines are read and buffered so as to have more
1768            than one at a time available.
1769    
1770        (d) Implemented a pcregrep test script.
1771    
1772        (e) Added the -M (multiline match) option. This allows patterns to match
1773            over several lines of the subject. The buffering ensures that at least
1774            8K, or the rest of the document (whichever is the shorter) is available
1775            for matching (and similarly the previous 8K for lookbehind assertions).
1776    
1777        (f) Changed the --help output so that it now says
1778    
1779              -w, --word-regex(p)
1780    
1781            instead of two lines, one with "regex" and the other with "regexp"
1782            because that confused at least one person since the short forms are the
1783            same. (This required a bit of code, as the output is generated
1784            automatically from a table. It wasn't just a text change.)
1785    
1786        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1787            option but starts with a hyphen. Could be a pattern or a path name
1788            starting with a hyphen, for instance.
1789    
1790        (h) "-" can be given as a file name to represent stdin.
1791    
1792        (i) When file names are being printed, "(standard input)" is used for
1793            the standard input, for compatibility with GNU grep. Previously
1794            "<stdin>" was used.
1795    
1796        (j) The option --label=xxx can be used to supply a name to be used for
1797            stdin when file names are being printed. There is no short form.
1798    
1799        (k) Re-factored the options decoding logic because we are going to add
1800            two more options that take data. Such options can now be given in four
1801            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1802    
1803        (l) Added the -A, -B, and -C options for requesting that lines of context
1804            around matches be printed.
1805    
1806        (m) Added the -L option to print the names of files that do not contain
1807            any matching lines, that is, the complement of -l.
1808    
1809        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1810            continue to scan other files.
1811    
1812        (o) The -s option was incorrectly implemented. For compatibility with other
1813            greps, it now suppresses the error message for a non-existent or non-
1814            accessible file (but not the return code). There is a new option called
1815            -q that suppresses the output of matching lines, which was what -s was
1816            previously doing.
1817    
1818        (p) Added --include and --exclude options to specify files for inclusion
1819            and exclusion when recursing.
1820    
1821    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1822        Hopefully, it now does.
1823    
1824    12. Missing cast in pcre_study().
1825    
1826    13. Added an "uninstall" target to the makefile.
1827    
1828    14. Replaced "extern" in the function prototypes in Makefile.in with
1829        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1830        world, but is set differently for Windows.
1831    
1832    15. Added a second compiling function called pcre_compile2(). The only
1833        difference is that it has an extra argument, which is a pointer to an
1834        integer error code. When there is a compile-time failure, this is set
1835        non-zero, in addition to the error test pointer being set to point to an
1836        error message. The new argument may be NULL if no error number is required
1837        (but then you may as well call pcre_compile(), which is now just a
1838        wrapper). This facility is provided because some applications need a
1839        numeric error indication, but it has also enabled me to tidy up the way
1840        compile-time errors are handled in the POSIX wrapper.
1841    
1842    16. Added VPATH=.libs to the makefile; this should help when building with one
1843        prefix path and installing with another. (Or so I'm told by someone who
1844        knows more about this stuff than I do.)
1845    
1846    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1847        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1848        match everything, including newlines. This is not POSIX-compatible, but
1849        somebody wanted the feature. From pcretest it can be activated by using
1850        both the P and the s flags.
1851    
1852    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1853    
1854    19. libpcre.pc was being incorrectly installed as executable.
1855    
1856    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1857        it now also looks for '\r' so that it will work unmodified on Windows.
1858    
1859    21. Added Google's contributed C++ wrapper to the distribution.
1860    
1861    22. Added some untidy missing memory free() calls in pcretest, to keep
1862        Electric Fence happy when testing.
1863    
1864    
1865    
1866    Version 5.0 13-Sep-04
1867    ---------------------
1868    
1869     1. Internal change: literal characters are no longer packed up into items
1870        containing multiple characters in a single byte-string. Each character
1871        is now matched using a separate opcode. However, there may be more than one
1872        byte in the character in UTF-8 mode.
1873    
1874     2. The pcre_callout_block structure has two new fields: pattern_position and
1875        next_item_length. These contain the offset in the pattern to the next match
1876        item, and its length, respectively.
1877    
1878     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1879        insertion of callouts before each pattern item. Added the /C option to
1880        pcretest to make use of this.
1881    
1882     4. On the advice of a Windows user, the lines
1883    
1884          #if defined(_WIN32) || defined(WIN32)
1885          _setmode( _fileno( stdout ), 0x8000 );
1886          #endif  /* defined(_WIN32) || defined(WIN32) */
1887    
1888        have been added to the source of pcretest. This apparently does useful
1889        magic in relation to line terminators.
1890    
1891     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1892        for the benefit of those environments where the "b" makes a difference.
1893    
1894     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1895        to know about it. I have put a hack into configure.in that adds in code
1896        to set GCC=yes if CC=icc. This seems to end up at a point in the
1897        generated configure script that is early enough to affect the setting of
1898        compiler options, which is what is needed, but I have no means of testing
1899        whether it really works. (The user who reported this had patched the
1900        generated configure script, which of course I cannot do.)
1901    
1902        LATER: After change 22 below (new libtool files), the configure script
1903        seems to know about icc (and also ecc). Therefore, I have commented out
1904        this hack in configure.in.
1905    
1906     7. Added support for pkg-config (2 patches were sent in).
1907    
1908     8. Negated POSIX character classes that used a combination of internal tables
1909        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1910        [[:^ascii]]. Typically, they would match almost any characters. The other
1911        POSIX classes were not broken in this way.
1912    
1913     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1914        to find the match, as PCRE was deluded into thinking that the match had to
1915        start at the start point or following a newline. The same bug applied to
1916        patterns with negative forward assertions or any backward assertions
1917        preceding ".*" at the start, unless the pattern required a fixed first
1918        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1919    
1920    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1921        starting at the last subject character, bytes beyond the end of the subject
1922        string were read.
1923    
1924    11. Renamed the variable "class" as "classbits" to make life easier for C++
1925        users. (Previously there was a macro definition, but it apparently wasn't
1926        enough.)
1927    
1928    12. Added the new field "tables" to the extra data so that tables can be passed
1929        in at exec time, or the internal tables can be re-selected. This allows
1930        a compiled regex to be saved and re-used at a later time by a different
1931        program that might have everything at different addresses.
1932    
1933    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1934        -R library as well as a -L library.
1935    
1936    14. The debugging options of pcretest (-d on the command line or D on a
1937        pattern) showed incorrect output for anything following an extended class
1938        that contained multibyte characters and which was followed by a quantifier.
1939    
1940    15. Added optional support for general category Unicode character properties
1941        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1942        support. It adds about 90K to the size of the library. The meanings of the
1943        inbuilt class escapes such as \d and \s have NOT been changed.
1944    
1945    16. Updated pcredemo.c to include calls to free() to release the memory for the
1946        compiled pattern.
1947    
1948    17. The generated file chartables.c was being created in the source directory
1949        instead of in the building directory. This caused the build to fail if the
1950        source directory was different from the building directory, and was
1951        read-only.
1952    
1953    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1954        file. No doubt somebody will tell me if they don't make sense... Also added
1955        Dan Mooney's comments about building on OpenVMS.
1956    
1957    19. Added support for partial matching via the PCRE_PARTIAL option for
1958        pcre_exec() and the \P data escape in pcretest.
1959    
1960    20. Extended pcretest with 3 new pattern features:
1961    
1962        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1963              write the compiled pattern to the file whose name is "rest-of-line".
1964              This is a straight binary dump of the data, with the saved pointer to
1965              the character tables forced to be NULL. The study data, if any, is
1966              written too. After writing, pcretest reads a new pattern.
1967    
1968        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1969              compiled pattern from the given file. There must not be any
1970              occurrences of "<" in the file name (pretty unlikely); if there are,
1971              pcretest will instead treat the initial "<" as a pattern delimiter.
1972              After reading in the pattern, pcretest goes on to read data lines as
1973              usual.
1974    
1975        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1976              and 16-bit fields in a compiled pattern, to simulate a pattern that
1977              was compiled on a host of opposite endianness.
1978    
1979    21. The pcre-exec() function can now cope with patterns that were compiled on
1980        hosts of opposite endianness, with this restriction:
1981    
1982          As for any compiled expression that is saved and used later, the tables
1983          pointer field cannot be preserved; the extra_data field in the arguments
1984          to pcre_exec() should be used to pass in a tables address if a value
1985          other than the default internal tables were used at compile time.
1986    
1987    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1988        now diagnosed as an error. Previously, most of the time, a negative number
1989        would have been treated as zero, but if in addition "ovector" was passed as
1990        NULL, a crash could occur.
1991    
1992    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1993        new versions from the libtool 1.5 distribution (the last one is a copy of
1994        a file called libtool.m4). This seems to have fixed the need to patch
1995        "configure" to support Darwin 1.3 (which I used to do). However, I still
1996        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1997        workstation).
1998    
1999    24. Changed the PCRE licence to be the more standard "BSD" licence.
2000    
2001    
2002    Version 4.5 01-Dec-03
2003    ---------------------
2004    
2005     1. There has been some re-arrangement of the code for the match() function so
2006        that it can be compiled in a version that does not call itself recursively.
2007        Instead, it keeps those local variables that need separate instances for
2008        each "recursion" in a frame on the heap, and gets/frees frames whenever it
2009        needs to "recurse". Keeping track of where control must go is done by means
2010        of setjmp/longjmp. The whole thing is implemented by a set of macros that
2011        hide most of the details from the main code, and operates only if
2012        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
2013        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
2014        operating.
2015    
2016        To make it easier for callers to provide specially tailored get/free
2017        functions for this usage, two new functions, pcre_stack_malloc, and
2018        pcre_stack_free, are used. They are always called in strict stacking order,
2019        and the size of block requested is always the same.
2020    
2021        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
2022        PCRE has been compiled to use the stack or the heap for recursion. The
2023        -C option of pcretest uses this to show which version is compiled.
2024    
2025        A new data escape \S, is added to pcretest; it causes the amounts of store
2026        obtained and freed by both kinds of malloc/free at match time to be added
2027        to the output.
2028    
2029     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
2030        what's available on my current Linux desktop machine.
2031    
2032     3. When matching a UTF-8 string, the test for a valid string at the start has
2033        been extended. If start_offset is not zero, PCRE now checks that it points
2034        to a byte that is the start of a UTF-8 character. If not, it returns
2035        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
2036        this is necessary because there may be backward assertions in the pattern.
2037        When matching the same subject several times, it may save resources to use
2038        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
2039    
2040     4. The code for checking the validity of UTF-8 strings has been tightened so
2041        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
2042        containing "overlong sequences".
2043    
2044     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
2045        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
2046        should have been "&", but it just so happened that all the cases this let
2047        through by mistake were picked up later in the function.
2048    
2049     6. I had used a variable called "isblank" - this is a C99 function, causing
2050        some compilers to warn. To avoid this, I renamed it (as "blankclass").
2051    
2052     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
2053        prompting; (b) run "./pcretest /dev/null" at the start of the test script
2054        so the version is shown; (c) stop "make test" echoing "./RunTest".
2055    
2056     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
2057    
2058     9. The prototype for memmove() for systems that don't have it was using
2059        size_t, but the inclusion of the header that defines size_t was later. I've
2060        moved the #includes for the C headers earlier to avoid this.
2061    
2062    10. Added some adjustments to the code to make it easier to compiler on certain
2063        special systems:
2064    
2065          (a) Some "const" qualifiers were missing.
2066          (b) Added the macro EXPORT before all exported functions; by default this
2067              is defined to be empty.
2068          (c) Changed the dftables auxiliary program (that builds chartables.c) so
2069              that it reads its output file name as an argument instead of writing
2070              to the standard output and assuming this can be redirected.
2071    
2072    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
2073        class containing characters with values greater than 255, PCRE compilation
2074        went into a loop.
2075    
2076    12. A recursive reference to a subpattern that was within another subpattern
2077        that had a minimum quantifier of zero caused PCRE to crash. For example,
2078        (x(y(?2))z)? provoked this bug with a subject that got as far as the
2079        recursion. If the recursively-called subpattern itself had a zero repeat,
2080        that was OK.
2081    
2082    13. In pcretest, the buffer for reading a data line was set at 30K, but the
2083        buffer into which it was copied (for escape processing) was still set at
2084        1024, so long lines caused crashes.
2085    
2086    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
2087        "internal error: code overflow...". This applied to any character class
2088        that was followed by a possessive quantifier.
2089    
2090    15. Modified the Makefile to add libpcre.la as a prerequisite for
2091        libpcreposix.la because I was told this is needed for a parallel build to
2092        work.
2093    
2094    16. If a pattern that contained .* following optional items at the start was
2095        studied, the wrong optimizing data was generated, leading to matching
2096        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
2097        matching string must start with a or b or c. The correct conclusion for
2098        this pattern is that a match can start with any character.
2099    
2100    
2101  Version 4.4 13-Aug-03  Version 4.4 13-Aug-03
2102  ---------------------  ---------------------
2103    

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