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

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