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

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