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revision 127 by ph10, Mon Mar 19 11:44:45 2007 UTC revision 381 by ph10, Tue Mar 3 16:08:23 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  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    
49    Version 7.8 05-Sep-08
50    ---------------------
51    
52    1.  Replaced UCP searching code with optimized version as implemented for Ad
53        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
54        stage table and inline lookup instead of a function, giving speed ups of 2
55        to 5 times on some simple patterns that I tested. Permission was given to
56        distribute the MultiStage2.py script that generates the tables (it's not in
57        the tarball, but is in the Subversion repository).
58    
59    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
60        scripts.
61    
62    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
63        a group with a zero qualifier. The result of the study could be incorrect,
64        or the function might crash, depending on the pattern.
65    
66    4.  Caseless matching was not working for non-ASCII characters in back
67        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
68        It now works when Unicode Property Support is available.
69    
70    5.  In pcretest, an escape such as \x{de} in the data was always generating
71        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
72        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
73        truncation.
74    
75    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
76    
77    7.  Added two (int) casts to pcregrep when printing the difference of two
78        pointers, in case they are 64-bit values.
79    
80    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
81        test 2 if it fails.
82    
83    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
84        and a #define of that name to empty if it is not externally set. This is to
85        allow users of MSVC to set it if necessary.
86    
87    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
88        the convenience functions in the pcre_get.c source file.
89    
90    11. An option change at the start of a pattern that had top-level alternatives
91        could cause overwriting and/or a crash. This command provoked a crash in
92        some environments:
93    
94          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
95    
96        This potential security problem was recorded as CVE-2008-2371.
97    
98    12. For a pattern where the match had to start at the beginning or immediately
99        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
100        pcre_dfa_exec() could read past the end of the passed subject if there was
101        no match. To help with detecting such bugs (e.g. with valgrind), I modified
102        pcretest so that it places the subject at the end of its malloc-ed buffer.
103    
104    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
105        exec() might read past the end of the data buffer in UTF-8 mode.
106    
107    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
108        the data contained the byte 0x85 as part of a UTF-8 character within its
109        first line. This applied both to normal and DFA matching.
110    
111    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
112        /^[^d]*?$/8 failed to match "abc".
113    
114    16. Added a missing copyright notice to pcrecpp_internal.h.
115    
116    17. Make it more clear in the documentation that values returned from
117        pcre_exec() in ovector are byte offsets, not character counts.
118    
119    18. Tidied a few places to stop certain compilers from issuing warnings.
120    
121    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
122        supplied by Stefan Weber. I made a further small update for 7.8 because
123        there is a change of source arrangements: the pcre_searchfuncs.c module is
124        replaced by pcre_ucd.c.
125    
126    
127    Version 7.7 07-May-08
128    ---------------------
129    
130    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
131        a string to a long long, pretend we don't even have a long long." This is
132        done by checking for the strtoq, strtoll, and _strtoi64 functions.
133    
134    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
135        pre-7.6 versions, which defined a global no_arg variable instead of putting
136        it in the RE class. (See also #8 below.)
137    
138    3.  Remove a line of dead code, identified by coverity and reported by Nuno
139        Lopes.
140    
141    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
142    
143        (1) The include/exclude patterns were being applied to the whole pathnames
144            of files, instead of just to the final components.
145    
146        (2) If there was more than one level of directory, the subdirectories were
147            skipped unless they satisfied the include/exclude conditions. This is
148            inconsistent with GNU grep (and could even be seen as contrary to the
149            pcregrep specification - which I improved to make it absolutely clear).
150            The action now is always to scan all levels of directory, and just
151            apply the include/exclude patterns to regular files.
152    
153    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
154        --exclude_dir in the tests to avoid scanning .svn directories.
155    
156    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
157        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
158        doesn't support NULs in patterns.
159    
160    7.  Added some missing "const"s to declarations of static tables in
161        pcre_compile.c and pcre_dfa_exec.c.
162    
163    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
164        caused by fix #2  above. (Subsequently also a second patch to fix the
165        first patch. And a third patch - this was a messy problem.)
166    
167    9.  Applied Craig's patch to remove the use of push_back().
168    
169    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
170        matching function regexec().
171    
172    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
173        which, however, unlike Perl's \g{...}, are subroutine calls, not back
174        references. PCRE supports relative numbers with this syntax (I don't think
175        Oniguruma does).
176    
177    12. Previously, a group with a zero repeat such as (...){0} was completely
178        omitted from the compiled regex. However, this means that if the group
179        was called as a subroutine from elsewhere in the pattern, things went wrong
180        (an internal error was given). Such groups are now left in the compiled
181        pattern, with a new opcode that causes them to be skipped at execution
182        time.
183    
184    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
185        to the way PCRE behaves:
186    
187        (a) A lone ] character is dis-allowed (Perl treats it as data).
188    
189        (b) A back reference to an unmatched subpattern matches an empty string
190            (Perl fails the current match path).
191    
192        (c) A data ] in a character class must be notated as \] because if the
193            first data character in a class is ], it defines an empty class. (In
194            Perl it is not possible to have an empty class.) The empty class []
195            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
196            The negative empty class [^] matches any one character, independently
197            of the DOTALL setting.
198    
199    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
200        non-existent subpattern following a character class starting with ']' and
201        containing () gave an internal compiling error instead of "reference to
202        non-existent subpattern". Fortunately, when the pattern did exist, the
203        compiled code was correct. (When scanning forwards to check for the
204        existencd of the subpattern, it was treating the data ']' as terminating
205        the class, so got the count wrong. When actually compiling, the reference
206        was subsequently set up correctly.)
207    
208    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
209        it was being rejected as not supported by pcre_dfa_exec(), even though
210        other assertions are supported. I have made pcre_dfa_exec() support
211        (*FAIL).
212    
213    16. The implementation of 13c above involved the invention of a new opcode,
214        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
215        cannot be changed at match time, I realized I could make a small
216        improvement to matching performance by compiling OP_ALLANY instead of
217        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
218        on the OP_ANY path.
219    
220    17. Compiling pcretest on Windows with readline support failed without the
221        following two fixes: (1) Make the unistd.h include conditional on
222        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
223    
224    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
225        ncurses library to be included for pcretest when ReadLine support is
226        requested, but also to allow for it to be overridden. This patch came from
227        Daniel Bergström.
228    
229    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
230        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
231        any errors with the current Unicode tables. Thanks to Peter Kankowski for
232        spotting this.
233    
234    
235    Version 7.6 28-Jan-08
236    ---------------------
237    
238    1.  A character class containing a very large number of characters with
239        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
240        overflow.
241    
242    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
243        HAVE_LONG_LONG is not defined.
244    
245    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
246        bring them up to date and include new features. This patch includes:
247    
248        - Fixed PH's badly added libz and libbz2 support.
249        - Fixed a problem with static linking.
250        - Added pcredemo. [But later removed - see 7 below.]
251        - Fixed dftables problem and added an option.
252        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
253            HAVE_LONG_LONG.
254        - Added readline support for pcretest.
255        - Added an listing of the option settings after cmake has run.
256    
257    4.  A user submitted a patch to Makefile that makes it easy to create
258        "pcre.dll" under mingw when using Configure/Make. I added stuff to
259        Makefile.am that cause it to include this special target, without
260        affecting anything else. Note that the same mingw target plus all
261        the other distribution libraries and programs are now supported
262        when configuring with CMake (see 6 below) instead of with
263        Configure/Make.
264    
265    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
266        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
267        exported in the Windows port". It has not yet been confirmed that the patch
268        solves the problem, but it does no harm.
269    
270    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
271        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
272        with CMake, and also correct the comment about stack recursion.
273    
274    7.  Remove the automatic building of pcredemo from the ./configure system and
275        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
276        of a program that users should build themselves after PCRE is installed, so
277        building it automatically is not really right. What is more, it gave
278        trouble in some build environments.
279    
280    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
281    
282    
283    Version 7.5 10-Jan-08
284    ---------------------
285    
286    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
287        values in parens when parsing an RE using the C++ wrapper."
288    
289    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
290        Characters greater than 255 were excluded from the class instead of being
291        included.
292    
293    3.  The same bug as (2) above applied to negated POSIX classes such as
294        [:^space:].
295    
296    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
297        defined or documented. It seems to have been a typo for PCRE_STATIC, so
298        I have changed it.
299    
300    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
301        first named subpattern) and a construct such as (?&a) would reference the
302        first named subpattern whose name started with "a" (in other words, the
303        length check was missing). Both these problems are fixed. "Subpattern name
304        expected" is now given for (?&) (a zero-length name), and this patch also
305        makes it give the same error for \k'' (previously it complained that that
306        was a reference to a non-existent subpattern).
307    
308    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
309        this is right because (?- can be followed by option settings as well as by
310        digits. I have, however, made the messages clearer.
311    
312    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
313        than the number used in the conditional) now cause a compile-time error.
314        This is actually not compatible with Perl, which accepts such patterns, but
315        treats the conditional as always being FALSE (as PCRE used to), but it
316        seems to me that giving a diagnostic is better.
317    
318    8.  Change "alphameric" to the more common word "alphanumeric" in comments
319        and messages.
320    
321    9.  Fix two occurrences of "backslash" in comments that should have been
322        "backspace".
323    
324    10. Remove two redundant lines of code that can never be obeyed (their function
325        was moved elsewhere).
326    
327    11. The program that makes PCRE's Unicode character property table had a bug
328        which caused it to generate incorrect table entries for sequences of
329        characters that have the same character type, but are in different scripts.
330        It amalgamated them into a single range, with the script of the first of
331        them. In other words, some characters were in the wrong script. There were
332        thirteen such cases, affecting characters in the following ranges:
333    
334          U+002b0 - U+002c1
335          U+0060c - U+0060d
336          U+0061e - U+00612
337          U+0064b - U+0065e
338          U+0074d - U+0076d
339          U+01800 - U+01805
340          U+01d00 - U+01d77
341          U+01d9b - U+01dbf
342          U+0200b - U+0200f
343          U+030fc - U+030fe
344          U+03260 - U+0327f
345          U+0fb46 - U+0fbb1
346          U+10450 - U+1049d
347    
348    12. The -o option (show only the matching part of a line) for pcregrep was not
349        compatible with GNU grep in that, if there was more than one match in a
350        line, it showed only the first of them. It now behaves in the same way as
351        GNU grep.
352    
353    13. If the -o and -v options were combined for pcregrep, it printed a blank
354        line for every non-matching line. GNU grep prints nothing, and pcregrep now
355        does the same. The return code can be used to tell if there were any
356        non-matching lines.
357    
358    14. Added --file-offsets and --line-offsets to pcregrep.
359    
360    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
361        infinitely looping recursion. The bug was that positive lookaheads were not
362        being skipped when checking for a possible empty match (negative lookaheads
363        and both kinds of lookbehind were skipped).
364    
365    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
366        inclusion of <windows.h> to before rather than after the definition of
367        INVALID_FILE_ATTRIBUTES (patch from David Byron).
368    
369    17. Specifying a possessive quantifier with a specific limit for a Unicode
370        character property caused pcre_compile() to compile bad code, which led at
371        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
372        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
373        caused the error; without that there was no problem.
374    
375    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
376    
377    19. Added --enable-pcretest-libreadline.
378    
379    20. In pcrecpp.cc, the variable 'count' was incremented twice in
380        RE::GlobalReplace(). As a result, the number of replacements returned was
381        double what it should be. I removed one of the increments, but Craig sent a
382        later patch that removed the other one (the right fix) and added unit tests
383        that check the return values (which was not done before).
384    
385    21. Several CMake things:
386    
387        (1) Arranged that, when cmake is used on Unix, the libraries end up with
388            the names libpcre and libpcreposix, not just pcre and pcreposix.
389    
390        (2) The above change means that pcretest and pcregrep are now correctly
391            linked with the newly-built libraries, not previously installed ones.
392    
393        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
394    
395    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
396        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
397        UTF-8 newline character). The key issue is that the pattern starts .*;
398        this means that the match must be either at the beginning, or after a
399        newline. The bug was in the code for advancing after a failed match and
400        checking that the new position followed a newline. It was not taking
401        account of UTF-8 characters correctly.
402    
403    23. PCRE was behaving differently from Perl in the way it recognized POSIX
404        character classes. PCRE was not treating the sequence [:...:] as a
405        character class unless the ... were all letters. Perl, however, seems to
406        allow any characters between [: and :], though of course it rejects as
407        unknown any "names" that contain non-letters, because all the known class
408        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
409        for example, whereas PCRE did not - it did not recognize a POSIX character
410        class. This seemed a bit dangerous, so the code has been changed to be
411        closer to Perl. The behaviour is not identical to Perl, because PCRE will
412        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
413        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
414        Perl does, and where it didn't before.
415    
416    24. Rewrite so as to remove the single use of %n from pcregrep because in some
417        Windows environments %n is disabled by default.
418    
419    
420    Version 7.4 21-Sep-07
421    ---------------------
422    
423    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
424        means that a class such as [\s] counted as "explicit reference to CR or
425        LF". That isn't really right - the whole point of the change was to try to
426        help when there was an actual mention of one of the two characters. So now
427        the change happens only if \r or \n (or a literal CR or LF) character is
428        encountered.
429    
430    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
431        of both had grown to the point where there were only 3 bits left.
432        Fortunately, there was spare space in the data structure, and so I have
433        moved the internal flags into a new 16-bit field to free up more option
434        bits.
435    
436    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
437        but did not set the internal JCHANGED flag - either of these is enough to
438        control the way the "get" function works - but the PCRE_INFO_JCHANGED
439        facility is supposed to tell if (?J) was ever used, so now (?J) at the
440        start sets both bits.
441    
442    4.  Added options (at build time, compile time, exec time) to change \R from
443        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
444    
445    5.  doc/pcresyntax.html was missing from the distribution.
446    
447    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
448        compatibility, even though it is no longer used.
449    
450    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
451        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
452        windows.h file is present (where different names are used). [This was
453        reversed later after testing - see 16 below.]
454    
455    8.  Changed all #include <config.h> to #include "config.h". There were also
456        some further <pcre.h> cases that I changed to "pcre.h".
457    
458    9.  When pcregrep was used with the --colour option, it missed the line ending
459        sequence off the lines that it output.
460    
461    10. It was pointed out to me that arrays of string pointers cause lots of
462        relocations when a shared library is dynamically loaded. A technique of
463        using a single long string with a table of offsets can drastically reduce
464        these. I have refactored PCRE in four places to do this. The result is
465        dramatic:
466    
467          Originally:                          290
468          After changing UCP table:            187
469          After changing error message table:   43
470          After changing table of "verbs"       36
471          After changing table of Posix names   22
472    
473        Thanks to the folks working on Gregex for glib for this insight.
474    
475    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
476        unicode-properties was also set.
477    
478    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
479    
480    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
481        checked only for CRLF.
482    
483    14. Added casts to pcretest.c to avoid compiler warnings.
484    
485    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
486    
487    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
488        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
489        entirely. This removes changes made in 7 above.
490    
491    17. The CMake files have been updated, and there is now more information about
492        building with CMake in the NON-UNIX-USE document.
493    
494    
495    Version 7.3 28-Aug-07
496    ---------------------
497    
498     1. In the rejigging of the build system that eventually resulted in 7.1, the
499        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
500        brackets there is not right, since it causes compilers to look for an
501        installed pcre.h, not the version that is in the source that is being
502        compiled (which of course may be different). I have changed it back to:
503    
504          #include "pcre.h"
505    
506        I have a vague recollection that the change was concerned with compiling in
507        different directories, but in the new build system, that is taken care of
508        by the VPATH setting the Makefile.
509    
510     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
511        when the subject happened to end in the byte 0x85 (e.g. if the last
512        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
513        characters but of course it shouldn't be taken as a newline when it is part
514        of another character. The bug was that, for an unlimited repeat of . in
515        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
516        characters when looking for a newline.
517    
518     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
519    
520     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
521        in debug output.
522    
523     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
524        long printing in the pcrecpp unittest when running under MinGW.
525    
526     6. ESC_K was left out of the EBCDIC table.
527    
528     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
529        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
530        limit also applies to "virtual nesting" when a pattern is recursive, and in
531        this case 1000 isn't so big. I have been able to remove this limit at the
532        expense of backing off one optimization in certain circumstances. Normally,
533        when pcre_exec() would call its internal match() function recursively and
534        immediately return the result unconditionally, it uses a "tail recursion"
535        feature to save stack. However, when a subpattern that can match an empty
536        string has an unlimited repetition quantifier, it no longer makes this
537        optimization. That gives it a stack frame in which to save the data for
538        checking that an empty string has been matched. Previously this was taken
539        from the 1000-entry workspace that had been reserved. So now there is no
540        explicit limit, but more stack is used.
541    
542     8. Applied Daniel's patches to solve problems with the import/export magic
543        syntax that is required for Windows, and which was going wrong for the
544        pcreposix and pcrecpp parts of the library. These were overlooked when this
545        problem was solved for the main library.
546    
547     9. There were some crude static tests to avoid integer overflow when computing
548        the size of patterns that contain repeated groups with explicit upper
549        limits. As the maximum quantifier is 65535, the maximum group length was
550        set at 30,000 so that the product of these two numbers did not overflow a
551        32-bit integer. However, it turns out that people want to use groups that
552        are longer than 30,000 bytes (though not repeat them that many times).
553        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
554        made it possible to implement the integer overflow checks in a much more
555        dynamic way, which I have now done. The artificial limitation on group
556        length has been removed - we now have only the limit on the total length of
557        the compiled pattern, which depends on the LINK_SIZE setting.
558    
559    10. Fixed a bug in the documentation for get/copy named substring when
560        duplicate names are permitted. If none of the named substrings are set, the
561        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
562        empty string.
563    
564    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
565        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
566        because the ] is interpreted as the first data character and the
567        terminating ] is not found. PCRE has been made compatible with Perl in this
568        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
569        cause memory overwriting.
570    
571    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
572        string has been matched (to stop an infinite loop). It was not recognizing
573        a conditional subpattern that could match an empty string if that
574        subpattern was within another subpattern. For example, it looped when
575        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
576        condition was not nested. This bug has been fixed.
577    
578    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
579        past the start of the subject in the presence of bytes with the top bit
580        set, for example "\x8aBCD".
581    
582    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
583        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
584    
585    14. Optimized (?!) to (*FAIL).
586    
587    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
588        This restricts code points to be within the range 0 to 0x10FFFF, excluding
589        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
590        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
591        does: it's just the validity check that is more restrictive.
592    
593    16. Inserted checks for integer overflows during escape sequence (backslash)
594        processing, and also fixed erroneous offset values for syntax errors during
595        backslash processing.
596    
597    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
598        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
599    
600    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
601        caused an overrun.
602    
603    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
604        something other than just ASCII characters) inside a group that had an
605        unlimited repeat caused a loop at compile time (while checking to see
606        whether the group could match an empty string).
607    
608    20. Debugging a pattern containing \p or \P could cause a crash. For example,
609        [\P{Any}] did so. (Error in the code for printing property names.)
610    
611    21. An orphan \E inside a character class could cause a crash.
612    
613    22. A repeated capturing bracket such as (A)? could cause a wild memory
614        reference during compilation.
615    
616    23. There are several functions in pcre_compile() that scan along a compiled
617        expression for various reasons (e.g. to see if it's fixed length for look
618        behind). There were bugs in these functions when a repeated \p or \P was
619        present in the pattern. These operators have additional parameters compared
620        with \d, etc, and these were not being taken into account when moving along
621        the compiled data. Specifically:
622    
623        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
624            length.
625    
626        (b) An item such as \pL+ within a repeated group could cause crashes or
627            loops.
628    
629        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
630            "reference to non-existent subpattern" error.
631    
632        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
633    
634    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
635        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
636    
637    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
638    
639    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
640        character were causing crashes (broken optimization).
641    
642    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
643        \p or \P) caused a compile-time loop.
644    
645    28. More problems have arisen in unanchored patterns when CRLF is a valid line
646        break. For example, the unstudied pattern [\r\n]A does not match the string
647        "\r\nA" because change 7.0/46 below moves the current point on by two
648        characters after failing to match at the start. However, the pattern \nA
649        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
650        the same is true. There doesn't seem any very clean way out of this, but
651        what I have chosen to do makes the common cases work: PCRE now takes note
652        of whether there can be an explicit match for \r or \n anywhere in the
653        pattern, and if so, 7.0/46 no longer applies. As part of this change,
654        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
655        pattern has explicit CR or LF references.
656    
657    29. Added (*CR) etc for changing newline setting at start of pattern.
658    
659    
660    Version 7.2 19-Jun-07
661    ---------------------
662    
663     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
664        which is apparently normally available under Windows.
665    
666     2. Re-jig the pcregrep tests with different newline settings in an attempt
667        to make them independent of the local environment's newline setting.
668    
669     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
670    
671     4. Some of the "internals" tests were previously cut out when the link size
672        was not 2, because the output contained actual offsets. The recent new
673        "Z" feature of pcretest means that these can be cut out, making the tests
674        usable with all link sizes.
675    
676     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
677        stack recursion. This gives a massive performance boost under BSD, but just
678        a small improvement under Linux. However, it saves one field in the frame
679        in all cases.
680    
681     6. Added more features from the forthcoming Perl 5.10:
682    
683        (a) (?-n) (where n is a string of digits) is a relative subroutine or
684            recursion call. It refers to the nth most recently opened parentheses.
685    
686        (b) (?+n) is also a relative subroutine call; it refers to the nth next
687            to be opened parentheses.
688    
689        (c) Conditions that refer to capturing parentheses can be specified
690            relatively, for example, (?(-2)... or (?(+3)...
691    
692        (d) \K resets the start of the current match so that everything before
693            is not part of it.
694    
695        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
696    
697        (f) \g{name} is another synonym - part of Perl 5.10's unification of
698            reference syntax.
699    
700        (g) (?| introduces a group in which the numbering of parentheses in each
701            alternative starts with the same number.
702    
703        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
704    
705     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
706        PCRE_INFO_JCHANGED.
707    
708     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
709        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
710        for detecting groups that can match an empty string.
711    
712     9. A pattern with a very large number of alternatives (more than several
713        hundred) was running out of internal workspace during the pre-compile
714        phase, where pcre_compile() figures out how much memory will be needed. A
715        bit of new cunning has reduced the workspace needed for groups with
716        alternatives. The 1000-alternative test pattern now uses 12 bytes of
717        workspace instead of running out of the 4096 that are available.
718    
719    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
720    
721    11. Applied patch from Google to remove an optimization that didn't quite work.
722        The report of the bug said:
723    
724          pcrecpp::RE("a*").FullMatch("aaa") matches, while
725          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
726          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
727    
728    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
729        it matched the wrong number of bytes.
730    
731    
732    Version 7.1 24-Apr-07
733  ---------------------  ---------------------
734    
735   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 33  Version 7.1 12-Mar-07 Line 761  Version 7.1 12-Mar-07
761   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
762      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
763      makevp.bat for the current PCRE, using the additional files      makevp.bat for the current PCRE, using the additional files
764      makevp-compile.txt, makevp-linklib.txt, and pcregexp.pas.      makevp_c.txt, makevp_l.txt, and pcregexp.pas.
765    
766   6. A Windows user reported a minor discrepancy with test 2, which turned out   6. A Windows user reported a minor discrepancy with test 2, which turned out
767      to be caused by a trailing space on an input line that had got lost in his      to be caused by a trailing space on an input line that had got lost in his
# Line 116  Version 7.1 12-Mar-07 Line 844  Version 7.1 12-Mar-07
844  14. If erroroffset was passed as NULL to pcre_compile, it provoked a  14. If erroroffset was passed as NULL to pcre_compile, it provoked a
845      segmentation fault instead of returning the appropriate error message.      segmentation fault instead of returning the appropriate error message.
846    
847    15. In multiline mode when the newline sequence was set to "any", the pattern
848        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
849        This doesn't seem right; it now treats the CRLF combination as the line
850        ending, and so does not match in that case. It's only a pattern such as ^$
851        that would hit this one: something like ^ABC$ would have failed after \r
852        and then tried again after \r\n.
853    
854    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
855        in an attempt to make files that differ only in their line terminators
856        compare equal. This works on Linux.
857    
858    17. Under certain error circumstances pcregrep might try to free random memory
859        as it exited. This is now fixed, thanks to valgrind.
860    
861    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
862        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
863        was because its rules for how to advance for /g after matching an empty
864        string at the end of a line did not allow for this case. They now check for
865        it specially.
866    
867    20. pcretest is supposed to handle patterns and data of any length, by
868        extending its buffers when necessary. It was getting this wrong when the
869        buffer for a data line had to be extended.
870    
871    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
872        CRLF as a newline sequence.
873    
874    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
875        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
876        I have nevertheless tidied it up.
877    
878    23. Added some casts to kill warnings from HP-UX ia64 compiler.
879    
880    24. Added a man page for pcre-config.
881    
882    
883  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
884  ---------------------  ---------------------

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