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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    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   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 133  Version 7.1 12-Mar-07 Line 867  Version 7.1 12-Mar-07
867  19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string  19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
868      "abc\r\n\r\n", it found an unwanted second match after the second \r. This      "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      was because its rules for how to advance for /g after matching an empty
870      string did not allow for this case. They now check for it specially.      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  Version 7.0 19-Dec-06

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