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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        skipped when checking for this condition.
43    
44    
45    Version 7.8 05-Sep-08
46    ---------------------
47    
48    1.  Replaced UCP searching code with optimized version as implemented for Ad
49        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
50        stage table and inline lookup instead of a function, giving speed ups of 2
51        to 5 times on some simple patterns that I tested. Permission was given to
52        distribute the MultiStage2.py script that generates the tables (it's not in
53        the tarball, but is in the Subversion repository).
54    
55    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
56        scripts.
57    
58    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
59        a group with a zero qualifier. The result of the study could be incorrect,
60        or the function might crash, depending on the pattern.
61    
62    4.  Caseless matching was not working for non-ASCII characters in back
63        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
64        It now works when Unicode Property Support is available.
65    
66    5.  In pcretest, an escape such as \x{de} in the data was always generating
67        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
68        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
69        truncation.
70    
71    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
72    
73    7.  Added two (int) casts to pcregrep when printing the difference of two
74        pointers, in case they are 64-bit values.
75    
76    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
77        test 2 if it fails.
78    
79    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
80        and a #define of that name to empty if it is not externally set. This is to
81        allow users of MSVC to set it if necessary.
82    
83    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
84        the convenience functions in the pcre_get.c source file.
85    
86    11. An option change at the start of a pattern that had top-level alternatives
87        could cause overwriting and/or a crash. This command provoked a crash in
88        some environments:
89    
90          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
91    
92        This potential security problem was recorded as CVE-2008-2371.
93    
94    12. For a pattern where the match had to start at the beginning or immediately
95        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
96        pcre_dfa_exec() could read past the end of the passed subject if there was
97        no match. To help with detecting such bugs (e.g. with valgrind), I modified
98        pcretest so that it places the subject at the end of its malloc-ed buffer.
99    
100    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
101        exec() might read past the end of the data buffer in UTF-8 mode.
102    
103    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
104        the data contained the byte 0x85 as part of a UTF-8 character within its
105        first line. This applied both to normal and DFA matching.
106    
107    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
108        /^[^d]*?$/8 failed to match "abc".
109    
110    16. Added a missing copyright notice to pcrecpp_internal.h.
111    
112    17. Make it more clear in the documentation that values returned from
113        pcre_exec() in ovector are byte offsets, not character counts.
114    
115    18. Tidied a few places to stop certain compilers from issuing warnings.
116    
117    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
118        supplied by Stefan Weber. I made a further small update for 7.8 because
119        there is a change of source arrangements: the pcre_searchfuncs.c module is
120        replaced by pcre_ucd.c.
121    
122    
123    Version 7.7 07-May-08
124    ---------------------
125    
126    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
127        a string to a long long, pretend we don't even have a long long." This is
128        done by checking for the strtoq, strtoll, and _strtoi64 functions.
129    
130    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
131        pre-7.6 versions, which defined a global no_arg variable instead of putting
132        it in the RE class. (See also #8 below.)
133    
134    3.  Remove a line of dead code, identified by coverity and reported by Nuno
135        Lopes.
136    
137    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
138    
139        (1) The include/exclude patterns were being applied to the whole pathnames
140            of files, instead of just to the final components.
141    
142        (2) If there was more than one level of directory, the subdirectories were
143            skipped unless they satisfied the include/exclude conditions. This is
144            inconsistent with GNU grep (and could even be seen as contrary to the
145            pcregrep specification - which I improved to make it absolutely clear).
146            The action now is always to scan all levels of directory, and just
147            apply the include/exclude patterns to regular files.
148    
149    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
150        --exclude_dir in the tests to avoid scanning .svn directories.
151    
152    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
153        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
154        doesn't support NULs in patterns.
155    
156    7.  Added some missing "const"s to declarations of static tables in
157        pcre_compile.c and pcre_dfa_exec.c.
158    
159    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
160        caused by fix #2  above. (Subsequently also a second patch to fix the
161        first patch. And a third patch - this was a messy problem.)
162    
163    9.  Applied Craig's patch to remove the use of push_back().
164    
165    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
166        matching function regexec().
167    
168    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
169        which, however, unlike Perl's \g{...}, are subroutine calls, not back
170        references. PCRE supports relative numbers with this syntax (I don't think
171        Oniguruma does).
172    
173    12. Previously, a group with a zero repeat such as (...){0} was completely
174        omitted from the compiled regex. However, this means that if the group
175        was called as a subroutine from elsewhere in the pattern, things went wrong
176        (an internal error was given). Such groups are now left in the compiled
177        pattern, with a new opcode that causes them to be skipped at execution
178        time.
179    
180    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
181        to the way PCRE behaves:
182    
183        (a) A lone ] character is dis-allowed (Perl treats it as data).
184    
185        (b) A back reference to an unmatched subpattern matches an empty string
186            (Perl fails the current match path).
187    
188        (c) A data ] in a character class must be notated as \] because if the
189            first data character in a class is ], it defines an empty class. (In
190            Perl it is not possible to have an empty class.) The empty class []
191            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
192            The negative empty class [^] matches any one character, independently
193            of the DOTALL setting.
194    
195    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
196        non-existent subpattern following a character class starting with ']' and
197        containing () gave an internal compiling error instead of "reference to
198        non-existent subpattern". Fortunately, when the pattern did exist, the
199        compiled code was correct. (When scanning forwards to check for the
200        existencd of the subpattern, it was treating the data ']' as terminating
201        the class, so got the count wrong. When actually compiling, the reference
202        was subsequently set up correctly.)
203    
204    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
205        it was being rejected as not supported by pcre_dfa_exec(), even though
206        other assertions are supported. I have made pcre_dfa_exec() support
207        (*FAIL).
208    
209    16. The implementation of 13c above involved the invention of a new opcode,
210        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
211        cannot be changed at match time, I realized I could make a small
212        improvement to matching performance by compiling OP_ALLANY instead of
213        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
214        on the OP_ANY path.
215    
216    17. Compiling pcretest on Windows with readline support failed without the
217        following two fixes: (1) Make the unistd.h include conditional on
218        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
219    
220    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
221        ncurses library to be included for pcretest when ReadLine support is
222        requested, but also to allow for it to be overridden. This patch came from
223        Daniel Bergström.
224    
225    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
226        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
227        any errors with the current Unicode tables. Thanks to Peter Kankowski for
228        spotting this.
229    
230    
231    Version 7.6 28-Jan-08
232    ---------------------
233    
234    1.  A character class containing a very large number of characters with
235        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
236        overflow.
237    
238    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
239        HAVE_LONG_LONG is not defined.
240    
241    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
242        bring them up to date and include new features. This patch includes:
243    
244        - Fixed PH's badly added libz and libbz2 support.
245        - Fixed a problem with static linking.
246        - Added pcredemo. [But later removed - see 7 below.]
247        - Fixed dftables problem and added an option.
248        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
249            HAVE_LONG_LONG.
250        - Added readline support for pcretest.
251        - Added an listing of the option settings after cmake has run.
252    
253    4.  A user submitted a patch to Makefile that makes it easy to create
254        "pcre.dll" under mingw when using Configure/Make. I added stuff to
255        Makefile.am that cause it to include this special target, without
256        affecting anything else. Note that the same mingw target plus all
257        the other distribution libraries and programs are now supported
258        when configuring with CMake (see 6 below) instead of with
259        Configure/Make.
260    
261    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
262        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
263        exported in the Windows port". It has not yet been confirmed that the patch
264        solves the problem, but it does no harm.
265    
266    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
267        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
268        with CMake, and also correct the comment about stack recursion.
269    
270    7.  Remove the automatic building of pcredemo from the ./configure system and
271        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
272        of a program that users should build themselves after PCRE is installed, so
273        building it automatically is not really right. What is more, it gave
274        trouble in some build environments.
275    
276    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
277    
278    
279    Version 7.5 10-Jan-08
280    ---------------------
281    
282    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
283        values in parens when parsing an RE using the C++ wrapper."
284    
285    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
286        Characters greater than 255 were excluded from the class instead of being
287        included.
288    
289    3.  The same bug as (2) above applied to negated POSIX classes such as
290        [:^space:].
291    
292    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
293        defined or documented. It seems to have been a typo for PCRE_STATIC, so
294        I have changed it.
295    
296    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
297        first named subpattern) and a construct such as (?&a) would reference the
298        first named subpattern whose name started with "a" (in other words, the
299        length check was missing). Both these problems are fixed. "Subpattern name
300        expected" is now given for (?&) (a zero-length name), and this patch also
301        makes it give the same error for \k'' (previously it complained that that
302        was a reference to a non-existent subpattern).
303    
304    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
305        this is right because (?- can be followed by option settings as well as by
306        digits. I have, however, made the messages clearer.
307    
308    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
309        than the number used in the conditional) now cause a compile-time error.
310        This is actually not compatible with Perl, which accepts such patterns, but
311        treats the conditional as always being FALSE (as PCRE used to), but it
312        seems to me that giving a diagnostic is better.
313    
314    8.  Change "alphameric" to the more common word "alphanumeric" in comments
315        and messages.
316    
317    9.  Fix two occurrences of "backslash" in comments that should have been
318        "backspace".
319    
320    10. Remove two redundant lines of code that can never be obeyed (their function
321        was moved elsewhere).
322    
323    11. The program that makes PCRE's Unicode character property table had a bug
324        which caused it to generate incorrect table entries for sequences of
325        characters that have the same character type, but are in different scripts.
326        It amalgamated them into a single range, with the script of the first of
327        them. In other words, some characters were in the wrong script. There were
328        thirteen such cases, affecting characters in the following ranges:
329    
330          U+002b0 - U+002c1
331          U+0060c - U+0060d
332          U+0061e - U+00612
333          U+0064b - U+0065e
334          U+0074d - U+0076d
335          U+01800 - U+01805
336          U+01d00 - U+01d77
337          U+01d9b - U+01dbf
338          U+0200b - U+0200f
339          U+030fc - U+030fe
340          U+03260 - U+0327f
341          U+0fb46 - U+0fbb1
342          U+10450 - U+1049d
343    
344    12. The -o option (show only the matching part of a line) for pcregrep was not
345        compatible with GNU grep in that, if there was more than one match in a
346        line, it showed only the first of them. It now behaves in the same way as
347        GNU grep.
348    
349    13. If the -o and -v options were combined for pcregrep, it printed a blank
350        line for every non-matching line. GNU grep prints nothing, and pcregrep now
351        does the same. The return code can be used to tell if there were any
352        non-matching lines.
353    
354    14. Added --file-offsets and --line-offsets to pcregrep.
355    
356    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
357        infinitely looping recursion. The bug was that positive lookaheads were not
358        being skipped when checking for a possible empty match (negative lookaheads
359        and both kinds of lookbehind were skipped).
360    
361    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
362        inclusion of <windows.h> to before rather than after the definition of
363        INVALID_FILE_ATTRIBUTES (patch from David Byron).
364    
365    17. Specifying a possessive quantifier with a specific limit for a Unicode
366        character property caused pcre_compile() to compile bad code, which led at
367        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
368        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
369        caused the error; without that there was no problem.
370    
371    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
372    
373    19. Added --enable-pcretest-libreadline.
374    
375    20. In pcrecpp.cc, the variable 'count' was incremented twice in
376        RE::GlobalReplace(). As a result, the number of replacements returned was
377        double what it should be. I removed one of the increments, but Craig sent a
378        later patch that removed the other one (the right fix) and added unit tests
379        that check the return values (which was not done before).
380    
381    21. Several CMake things:
382    
383        (1) Arranged that, when cmake is used on Unix, the libraries end up with
384            the names libpcre and libpcreposix, not just pcre and pcreposix.
385    
386        (2) The above change means that pcretest and pcregrep are now correctly
387            linked with the newly-built libraries, not previously installed ones.
388    
389        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
390    
391    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
392        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
393        UTF-8 newline character). The key issue is that the pattern starts .*;
394        this means that the match must be either at the beginning, or after a
395        newline. The bug was in the code for advancing after a failed match and
396        checking that the new position followed a newline. It was not taking
397        account of UTF-8 characters correctly.
398    
399    23. PCRE was behaving differently from Perl in the way it recognized POSIX
400        character classes. PCRE was not treating the sequence [:...:] as a
401        character class unless the ... were all letters. Perl, however, seems to
402        allow any characters between [: and :], though of course it rejects as
403        unknown any "names" that contain non-letters, because all the known class
404        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
405        for example, whereas PCRE did not - it did not recognize a POSIX character
406        class. This seemed a bit dangerous, so the code has been changed to be
407        closer to Perl. The behaviour is not identical to Perl, because PCRE will
408        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
409        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
410        Perl does, and where it didn't before.
411    
412    24. Rewrite so as to remove the single use of %n from pcregrep because in some
413        Windows environments %n is disabled by default.
414    
415    
416    Version 7.4 21-Sep-07
417    ---------------------
418    
419    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
420        means that a class such as [\s] counted as "explicit reference to CR or
421        LF". That isn't really right - the whole point of the change was to try to
422        help when there was an actual mention of one of the two characters. So now
423        the change happens only if \r or \n (or a literal CR or LF) character is
424        encountered.
425    
426    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
427        of both had grown to the point where there were only 3 bits left.
428        Fortunately, there was spare space in the data structure, and so I have
429        moved the internal flags into a new 16-bit field to free up more option
430        bits.
431    
432    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
433        but did not set the internal JCHANGED flag - either of these is enough to
434        control the way the "get" function works - but the PCRE_INFO_JCHANGED
435        facility is supposed to tell if (?J) was ever used, so now (?J) at the
436        start sets both bits.
437    
438    4.  Added options (at build time, compile time, exec time) to change \R from
439        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
440    
441    5.  doc/pcresyntax.html was missing from the distribution.
442    
443    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
444        compatibility, even though it is no longer used.
445    
446    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
447        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
448        windows.h file is present (where different names are used). [This was
449        reversed later after testing - see 16 below.]
450    
451    8.  Changed all #include <config.h> to #include "config.h". There were also
452        some further <pcre.h> cases that I changed to "pcre.h".
453    
454    9.  When pcregrep was used with the --colour option, it missed the line ending
455        sequence off the lines that it output.
456    
457    10. It was pointed out to me that arrays of string pointers cause lots of
458        relocations when a shared library is dynamically loaded. A technique of
459        using a single long string with a table of offsets can drastically reduce
460        these. I have refactored PCRE in four places to do this. The result is
461        dramatic:
462    
463          Originally:                          290
464          After changing UCP table:            187
465          After changing error message table:   43
466          After changing table of "verbs"       36
467          After changing table of Posix names   22
468    
469        Thanks to the folks working on Gregex for glib for this insight.
470    
471    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
472        unicode-properties was also set.
473    
474    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
475    
476    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
477        checked only for CRLF.
478    
479    14. Added casts to pcretest.c to avoid compiler warnings.
480    
481    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
482    
483    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
484        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
485        entirely. This removes changes made in 7 above.
486    
487    17. The CMake files have been updated, and there is now more information about
488        building with CMake in the NON-UNIX-USE document.
489    
490    
491    Version 7.3 28-Aug-07
492    ---------------------
493    
494     1. In the rejigging of the build system that eventually resulted in 7.1, the
495        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
496        brackets there is not right, since it causes compilers to look for an
497        installed pcre.h, not the version that is in the source that is being
498        compiled (which of course may be different). I have changed it back to:
499    
500          #include "pcre.h"
501    
502        I have a vague recollection that the change was concerned with compiling in
503        different directories, but in the new build system, that is taken care of
504        by the VPATH setting the Makefile.
505    
506     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
507        when the subject happened to end in the byte 0x85 (e.g. if the last
508        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
509        characters but of course it shouldn't be taken as a newline when it is part
510        of another character. The bug was that, for an unlimited repeat of . in
511        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
512        characters when looking for a newline.
513    
514     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
515    
516     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
517        in debug output.
518    
519     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
520        long printing in the pcrecpp unittest when running under MinGW.
521    
522     6. ESC_K was left out of the EBCDIC table.
523    
524     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
525        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
526        limit also applies to "virtual nesting" when a pattern is recursive, and in
527        this case 1000 isn't so big. I have been able to remove this limit at the
528        expense of backing off one optimization in certain circumstances. Normally,
529        when pcre_exec() would call its internal match() function recursively and
530        immediately return the result unconditionally, it uses a "tail recursion"
531        feature to save stack. However, when a subpattern that can match an empty
532        string has an unlimited repetition quantifier, it no longer makes this
533        optimization. That gives it a stack frame in which to save the data for
534        checking that an empty string has been matched. Previously this was taken
535        from the 1000-entry workspace that had been reserved. So now there is no
536        explicit limit, but more stack is used.
537    
538     8. Applied Daniel's patches to solve problems with the import/export magic
539        syntax that is required for Windows, and which was going wrong for the
540        pcreposix and pcrecpp parts of the library. These were overlooked when this
541        problem was solved for the main library.
542    
543     9. There were some crude static tests to avoid integer overflow when computing
544        the size of patterns that contain repeated groups with explicit upper
545        limits. As the maximum quantifier is 65535, the maximum group length was
546        set at 30,000 so that the product of these two numbers did not overflow a
547        32-bit integer. However, it turns out that people want to use groups that
548        are longer than 30,000 bytes (though not repeat them that many times).
549        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
550        made it possible to implement the integer overflow checks in a much more
551        dynamic way, which I have now done. The artificial limitation on group
552        length has been removed - we now have only the limit on the total length of
553        the compiled pattern, which depends on the LINK_SIZE setting.
554    
555    10. Fixed a bug in the documentation for get/copy named substring when
556        duplicate names are permitted. If none of the named substrings are set, the
557        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
558        empty string.
559    
560    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
561        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
562        because the ] is interpreted as the first data character and the
563        terminating ] is not found. PCRE has been made compatible with Perl in this
564        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
565        cause memory overwriting.
566    
567    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
568        string has been matched (to stop an infinite loop). It was not recognizing
569        a conditional subpattern that could match an empty string if that
570        subpattern was within another subpattern. For example, it looped when
571        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
572        condition was not nested. This bug has been fixed.
573    
574    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
575        past the start of the subject in the presence of bytes with the top bit
576        set, for example "\x8aBCD".
577    
578    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
579        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
580    
581    14. Optimized (?!) to (*FAIL).
582    
583    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
584        This restricts code points to be within the range 0 to 0x10FFFF, excluding
585        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
586        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
587        does: it's just the validity check that is more restrictive.
588    
589    16. Inserted checks for integer overflows during escape sequence (backslash)
590        processing, and also fixed erroneous offset values for syntax errors during
591        backslash processing.
592    
593    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
594        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
595    
596    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
597        caused an overrun.
598    
599    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
600        something other than just ASCII characters) inside a group that had an
601        unlimited repeat caused a loop at compile time (while checking to see
602        whether the group could match an empty string).
603    
604    20. Debugging a pattern containing \p or \P could cause a crash. For example,
605        [\P{Any}] did so. (Error in the code for printing property names.)
606    
607    21. An orphan \E inside a character class could cause a crash.
608    
609    22. A repeated capturing bracket such as (A)? could cause a wild memory
610        reference during compilation.
611    
612    23. There are several functions in pcre_compile() that scan along a compiled
613        expression for various reasons (e.g. to see if it's fixed length for look
614        behind). There were bugs in these functions when a repeated \p or \P was
615        present in the pattern. These operators have additional parameters compared
616        with \d, etc, and these were not being taken into account when moving along
617        the compiled data. Specifically:
618    
619        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
620            length.
621    
622        (b) An item such as \pL+ within a repeated group could cause crashes or
623            loops.
624    
625        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
626            "reference to non-existent subpattern" error.
627    
628        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
629    
630    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
631        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
632    
633    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
634    
635    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
636        character were causing crashes (broken optimization).
637    
638    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
639        \p or \P) caused a compile-time loop.
640    
641    28. More problems have arisen in unanchored patterns when CRLF is a valid line
642        break. For example, the unstudied pattern [\r\n]A does not match the string
643        "\r\nA" because change 7.0/46 below moves the current point on by two
644        characters after failing to match at the start. However, the pattern \nA
645        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
646        the same is true. There doesn't seem any very clean way out of this, but
647        what I have chosen to do makes the common cases work: PCRE now takes note
648        of whether there can be an explicit match for \r or \n anywhere in the
649        pattern, and if so, 7.0/46 no longer applies. As part of this change,
650        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
651        pattern has explicit CR or LF references.
652    
653    29. Added (*CR) etc for changing newline setting at start of pattern.
654    
655    
656    Version 7.2 19-Jun-07
657    ---------------------
658    
659     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
660        which is apparently normally available under Windows.
661    
662     2. Re-jig the pcregrep tests with different newline settings in an attempt
663        to make them independent of the local environment's newline setting.
664    
665     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
666    
667     4. Some of the "internals" tests were previously cut out when the link size
668        was not 2, because the output contained actual offsets. The recent new
669        "Z" feature of pcretest means that these can be cut out, making the tests
670        usable with all link sizes.
671    
672     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
673        stack recursion. This gives a massive performance boost under BSD, but just
674        a small improvement under Linux. However, it saves one field in the frame
675        in all cases.
676    
677     6. Added more features from the forthcoming Perl 5.10:
678    
679        (a) (?-n) (where n is a string of digits) is a relative subroutine or
680            recursion call. It refers to the nth most recently opened parentheses.
681    
682        (b) (?+n) is also a relative subroutine call; it refers to the nth next
683            to be opened parentheses.
684    
685        (c) Conditions that refer to capturing parentheses can be specified
686            relatively, for example, (?(-2)... or (?(+3)...
687    
688        (d) \K resets the start of the current match so that everything before
689            is not part of it.
690    
691        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
692    
693        (f) \g{name} is another synonym - part of Perl 5.10's unification of
694            reference syntax.
695    
696        (g) (?| introduces a group in which the numbering of parentheses in each
697            alternative starts with the same number.
698    
699        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
700    
701     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
702        PCRE_INFO_JCHANGED.
703    
704     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
705        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
706        for detecting groups that can match an empty string.
707    
708     9. A pattern with a very large number of alternatives (more than several
709        hundred) was running out of internal workspace during the pre-compile
710        phase, where pcre_compile() figures out how much memory will be needed. A
711        bit of new cunning has reduced the workspace needed for groups with
712        alternatives. The 1000-alternative test pattern now uses 12 bytes of
713        workspace instead of running out of the 4096 that are available.
714    
715    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
716    
717    11. Applied patch from Google to remove an optimization that didn't quite work.
718        The report of the bug said:
719    
720          pcrecpp::RE("a*").FullMatch("aaa") matches, while
721          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
722          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
723    
724    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
725        it matched the wrong number of bytes.
726    
727    
728    Version 7.1 24-Apr-07
729  ---------------------  ---------------------
730    
731   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one

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