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

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