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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 01-May-07  Version 8.0 02 Jul-08
5    ---------------------
6    
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
13    
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
16    
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
20    
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
24    
25    5.  In pcretest, an escape such as \x{de} in the data was always generating
26        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28        truncation.
29    
30    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
31    
32    7.  Added two (int) casts to pcregrep when printing the difference of two
33        pointers, in case they are 64-bit values.
34    
35    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
36        test 2 if it fails.
37    
38    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
39        and a #define of that name to empty if it is not externally set. This is to
40        allow users of MSVC to set it if necessary.
41    
42    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
43        the convenience functions in the pcre_get.c source file.
44    
45    11. An option change at the start of a pattern that had top-level alternatives
46        could cause overwriting and/or a crash. This command provoked a crash in
47        some environments:
48    
49          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
50    
51        This potential security problem was recorded as CVE-2008-2371.
52    
53    12. For a pattern where the match had to start at the beginning or immediately
54        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
55        pcre_dfa_exec() could read past the end of the passed subject if there was
56        no match. To help with detecting such bugs (e.g. with valgrind), I modified
57        pcretest so that it places the subject at the end of its malloc-ed buffer.
58    
59    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
60        exec() might read past the end of the data buffer in UTF-8 mode.
61    
62    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
63        the data contained the byte 0x85 as part of a UTF-8 character within its
64        first line. This applied both to normal and DFA matching.
65    
66    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
67        /^[^d]*?$/8 failed to match "abc".
68    
69    
70    Version 7.7 07-May-08
71    ---------------------
72    
73    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
74        a string to a long long, pretend we don't even have a long long." This is
75        done by checking for the strtoq, strtoll, and _strtoi64 functions.
76    
77    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
78        pre-7.6 versions, which defined a global no_arg variable instead of putting
79        it in the RE class. (See also #8 below.)
80    
81    3.  Remove a line of dead code, identified by coverity and reported by Nuno
82        Lopes.
83    
84    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
85    
86        (1) The include/exclude patterns were being applied to the whole pathnames
87            of files, instead of just to the final components.
88    
89        (2) If there was more than one level of directory, the subdirectories were
90            skipped unless they satisfied the include/exclude conditions. This is
91            inconsistent with GNU grep (and could even be seen as contrary to the
92            pcregrep specification - which I improved to make it absolutely clear).
93            The action now is always to scan all levels of directory, and just
94            apply the include/exclude patterns to regular files.
95    
96    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
97        --exclude_dir in the tests to avoid scanning .svn directories.
98    
99    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
100        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
101        doesn't support NULs in patterns.
102    
103    7.  Added some missing "const"s to declarations of static tables in
104        pcre_compile.c and pcre_dfa_exec.c.
105    
106    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
107        caused by fix #2  above. (Subsequently also a second patch to fix the
108        first patch. And a third patch - this was a messy problem.)
109    
110    9.  Applied Craig's patch to remove the use of push_back().
111    
112    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
113        matching function regexec().
114    
115    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
116        which, however, unlike Perl's \g{...}, are subroutine calls, not back
117        references. PCRE supports relative numbers with this syntax (I don't think
118        Oniguruma does).
119    
120    12. Previously, a group with a zero repeat such as (...){0} was completely
121        omitted from the compiled regex. However, this means that if the group
122        was called as a subroutine from elsewhere in the pattern, things went wrong
123        (an internal error was given). Such groups are now left in the compiled
124        pattern, with a new opcode that causes them to be skipped at execution
125        time.
126    
127    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
128        to the way PCRE behaves:
129    
130        (a) A lone ] character is dis-allowed (Perl treats it as data).
131    
132        (b) A back reference to an unmatched subpattern matches an empty string
133            (Perl fails the current match path).
134    
135        (c) A data ] in a character class must be notated as \] because if the
136            first data character in a class is ], it defines an empty class. (In
137            Perl it is not possible to have an empty class.) The empty class []
138            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
139            The negative empty class [^] matches any one character, independently
140            of the DOTALL setting.
141    
142    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
143        non-existent subpattern following a character class starting with ']' and
144        containing () gave an internal compiling error instead of "reference to
145        non-existent subpattern". Fortunately, when the pattern did exist, the
146        compiled code was correct. (When scanning forwards to check for the
147        existencd of the subpattern, it was treating the data ']' as terminating
148        the class, so got the count wrong. When actually compiling, the reference
149        was subsequently set up correctly.)
150    
151    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
152        it was being rejected as not supported by pcre_dfa_exec(), even though
153        other assertions are supported. I have made pcre_dfa_exec() support
154        (*FAIL).
155    
156    16. The implementation of 13c above involved the invention of a new opcode,
157        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
158        cannot be changed at match time, I realized I could make a small
159        improvement to matching performance by compiling OP_ALLANY instead of
160        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
161        on the OP_ANY path.
162    
163    17. Compiling pcretest on Windows with readline support failed without the
164        following two fixes: (1) Make the unistd.h include conditional on
165        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
166    
167    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
168        ncurses library to be included for pcretest when ReadLine support is
169        requested, but also to allow for it to be overridden. This patch came from
170        Daniel Bergström.
171    
172    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
173        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
174        any errors with the current Unicode tables. Thanks to Peter Kankowski for
175        spotting this.
176    
177    
178    Version 7.6 28-Jan-08
179    ---------------------
180    
181    1.  A character class containing a very large number of characters with
182        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
183        overflow.
184    
185    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
186        HAVE_LONG_LONG is not defined.
187    
188    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
189        bring them up to date and include new features. This patch includes:
190    
191        - Fixed PH's badly added libz and libbz2 support.
192        - Fixed a problem with static linking.
193        - Added pcredemo. [But later removed - see 7 below.]
194        - Fixed dftables problem and added an option.
195        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
196            HAVE_LONG_LONG.
197        - Added readline support for pcretest.
198        - Added an listing of the option settings after cmake has run.
199    
200    4.  A user submitted a patch to Makefile that makes it easy to create
201        "pcre.dll" under mingw when using Configure/Make. I added stuff to
202        Makefile.am that cause it to include this special target, without
203        affecting anything else. Note that the same mingw target plus all
204        the other distribution libraries and programs are now supported
205        when configuring with CMake (see 6 below) instead of with
206        Configure/Make.
207    
208    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
209        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
210        exported in the Windows port". It has not yet been confirmed that the patch
211        solves the problem, but it does no harm.
212    
213    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
214        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
215        with CMake, and also correct the comment about stack recursion.
216    
217    7.  Remove the automatic building of pcredemo from the ./configure system and
218        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
219        of a program that users should build themselves after PCRE is installed, so
220        building it automatically is not really right. What is more, it gave
221        trouble in some build environments.
222    
223    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
224    
225    
226    Version 7.5 10-Jan-08
227    ---------------------
228    
229    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
230        values in parens when parsing an RE using the C++ wrapper."
231    
232    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
233        Characters greater than 255 were excluded from the class instead of being
234        included.
235    
236    3.  The same bug as (2) above applied to negated POSIX classes such as
237        [:^space:].
238    
239    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
240        defined or documented. It seems to have been a typo for PCRE_STATIC, so
241        I have changed it.
242    
243    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
244        first named subpattern) and a construct such as (?&a) would reference the
245        first named subpattern whose name started with "a" (in other words, the
246        length check was missing). Both these problems are fixed. "Subpattern name
247        expected" is now given for (?&) (a zero-length name), and this patch also
248        makes it give the same error for \k'' (previously it complained that that
249        was a reference to a non-existent subpattern).
250    
251    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
252        this is right because (?- can be followed by option settings as well as by
253        digits. I have, however, made the messages clearer.
254    
255    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
256        than the number used in the conditional) now cause a compile-time error.
257        This is actually not compatible with Perl, which accepts such patterns, but
258        treats the conditional as always being FALSE (as PCRE used to), but it
259        seems to me that giving a diagnostic is better.
260    
261    8.  Change "alphameric" to the more common word "alphanumeric" in comments
262        and messages.
263    
264    9.  Fix two occurrences of "backslash" in comments that should have been
265        "backspace".
266    
267    10. Remove two redundant lines of code that can never be obeyed (their function
268        was moved elsewhere).
269    
270    11. The program that makes PCRE's Unicode character property table had a bug
271        which caused it to generate incorrect table entries for sequences of
272        characters that have the same character type, but are in different scripts.
273        It amalgamated them into a single range, with the script of the first of
274        them. In other words, some characters were in the wrong script. There were
275        thirteen such cases, affecting characters in the following ranges:
276    
277          U+002b0 - U+002c1
278          U+0060c - U+0060d
279          U+0061e - U+00612
280          U+0064b - U+0065e
281          U+0074d - U+0076d
282          U+01800 - U+01805
283          U+01d00 - U+01d77
284          U+01d9b - U+01dbf
285          U+0200b - U+0200f
286          U+030fc - U+030fe
287          U+03260 - U+0327f
288          U+0fb46 - U+0fbb1
289          U+10450 - U+1049d
290    
291    12. The -o option (show only the matching part of a line) for pcregrep was not
292        compatible with GNU grep in that, if there was more than one match in a
293        line, it showed only the first of them. It now behaves in the same way as
294        GNU grep.
295    
296    13. If the -o and -v options were combined for pcregrep, it printed a blank
297        line for every non-matching line. GNU grep prints nothing, and pcregrep now
298        does the same. The return code can be used to tell if there were any
299        non-matching lines.
300    
301    14. Added --file-offsets and --line-offsets to pcregrep.
302    
303    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
304        infinitely looping recursion. The bug was that positive lookaheads were not
305        being skipped when checking for a possible empty match (negative lookaheads
306        and both kinds of lookbehind were skipped).
307    
308    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
309        inclusion of <windows.h> to before rather than after the definition of
310        INVALID_FILE_ATTRIBUTES (patch from David Byron).
311    
312    17. Specifying a possessive quantifier with a specific limit for a Unicode
313        character property caused pcre_compile() to compile bad code, which led at
314        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
315        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
316        caused the error; without that there was no problem.
317    
318    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
319    
320    19. Added --enable-pcretest-libreadline.
321    
322    20. In pcrecpp.cc, the variable 'count' was incremented twice in
323        RE::GlobalReplace(). As a result, the number of replacements returned was
324        double what it should be. I removed one of the increments, but Craig sent a
325        later patch that removed the other one (the right fix) and added unit tests
326        that check the return values (which was not done before).
327    
328    21. Several CMake things:
329    
330        (1) Arranged that, when cmake is used on Unix, the libraries end up with
331            the names libpcre and libpcreposix, not just pcre and pcreposix.
332    
333        (2) The above change means that pcretest and pcregrep are now correctly
334            linked with the newly-built libraries, not previously installed ones.
335    
336        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
337    
338    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
339        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
340        UTF-8 newline character). The key issue is that the pattern starts .*;
341        this means that the match must be either at the beginning, or after a
342        newline. The bug was in the code for advancing after a failed match and
343        checking that the new position followed a newline. It was not taking
344        account of UTF-8 characters correctly.
345    
346    23. PCRE was behaving differently from Perl in the way it recognized POSIX
347        character classes. PCRE was not treating the sequence [:...:] as a
348        character class unless the ... were all letters. Perl, however, seems to
349        allow any characters between [: and :], though of course it rejects as
350        unknown any "names" that contain non-letters, because all the known class
351        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
352        for example, whereas PCRE did not - it did not recognize a POSIX character
353        class. This seemed a bit dangerous, so the code has been changed to be
354        closer to Perl. The behaviour is not identical to Perl, because PCRE will
355        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
356        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
357        Perl does, and where it didn't before.
358    
359    24. Rewrite so as to remove the single use of %n from pcregrep because in some
360        Windows environments %n is disabled by default.
361    
362    
363    Version 7.4 21-Sep-07
364    ---------------------
365    
366    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
367        means that a class such as [\s] counted as "explicit reference to CR or
368        LF". That isn't really right - the whole point of the change was to try to
369        help when there was an actual mention of one of the two characters. So now
370        the change happens only if \r or \n (or a literal CR or LF) character is
371        encountered.
372    
373    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
374        of both had grown to the point where there were only 3 bits left.
375        Fortunately, there was spare space in the data structure, and so I have
376        moved the internal flags into a new 16-bit field to free up more option
377        bits.
378    
379    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
380        but did not set the internal JCHANGED flag - either of these is enough to
381        control the way the "get" function works - but the PCRE_INFO_JCHANGED
382        facility is supposed to tell if (?J) was ever used, so now (?J) at the
383        start sets both bits.
384    
385    4.  Added options (at build time, compile time, exec time) to change \R from
386        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
387    
388    5.  doc/pcresyntax.html was missing from the distribution.
389    
390    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
391        compatibility, even though it is no longer used.
392    
393    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
394        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
395        windows.h file is present (where different names are used). [This was
396        reversed later after testing - see 16 below.]
397    
398    8.  Changed all #include <config.h> to #include "config.h". There were also
399        some further <pcre.h> cases that I changed to "pcre.h".
400    
401    9.  When pcregrep was used with the --colour option, it missed the line ending
402        sequence off the lines that it output.
403    
404    10. It was pointed out to me that arrays of string pointers cause lots of
405        relocations when a shared library is dynamically loaded. A technique of
406        using a single long string with a table of offsets can drastically reduce
407        these. I have refactored PCRE in four places to do this. The result is
408        dramatic:
409    
410          Originally:                          290
411          After changing UCP table:            187
412          After changing error message table:   43
413          After changing table of "verbs"       36
414          After changing table of Posix names   22
415    
416        Thanks to the folks working on Gregex for glib for this insight.
417    
418    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
419        unicode-properties was also set.
420    
421    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
422    
423    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
424        checked only for CRLF.
425    
426    14. Added casts to pcretest.c to avoid compiler warnings.
427    
428    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
429    
430    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
431        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
432        entirely. This removes changes made in 7 above.
433    
434    17. The CMake files have been updated, and there is now more information about
435        building with CMake in the NON-UNIX-USE document.
436    
437    
438    Version 7.3 28-Aug-07
439    ---------------------
440    
441     1. In the rejigging of the build system that eventually resulted in 7.1, the
442        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
443        brackets there is not right, since it causes compilers to look for an
444        installed pcre.h, not the version that is in the source that is being
445        compiled (which of course may be different). I have changed it back to:
446    
447          #include "pcre.h"
448    
449        I have a vague recollection that the change was concerned with compiling in
450        different directories, but in the new build system, that is taken care of
451        by the VPATH setting the Makefile.
452    
453     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
454        when the subject happened to end in the byte 0x85 (e.g. if the last
455        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
456        characters but of course it shouldn't be taken as a newline when it is part
457        of another character. The bug was that, for an unlimited repeat of . in
458        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
459        characters when looking for a newline.
460    
461     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
462    
463     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
464        in debug output.
465    
466     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
467        long printing in the pcrecpp unittest when running under MinGW.
468    
469     6. ESC_K was left out of the EBCDIC table.
470    
471     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
472        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
473        limit also applies to "virtual nesting" when a pattern is recursive, and in
474        this case 1000 isn't so big. I have been able to remove this limit at the
475        expense of backing off one optimization in certain circumstances. Normally,
476        when pcre_exec() would call its internal match() function recursively and
477        immediately return the result unconditionally, it uses a "tail recursion"
478        feature to save stack. However, when a subpattern that can match an empty
479        string has an unlimited repetition quantifier, it no longer makes this
480        optimization. That gives it a stack frame in which to save the data for
481        checking that an empty string has been matched. Previously this was taken
482        from the 1000-entry workspace that had been reserved. So now there is no
483        explicit limit, but more stack is used.
484    
485     8. Applied Daniel's patches to solve problems with the import/export magic
486        syntax that is required for Windows, and which was going wrong for the
487        pcreposix and pcrecpp parts of the library. These were overlooked when this
488        problem was solved for the main library.
489    
490     9. There were some crude static tests to avoid integer overflow when computing
491        the size of patterns that contain repeated groups with explicit upper
492        limits. As the maximum quantifier is 65535, the maximum group length was
493        set at 30,000 so that the product of these two numbers did not overflow a
494        32-bit integer. However, it turns out that people want to use groups that
495        are longer than 30,000 bytes (though not repeat them that many times).
496        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
497        made it possible to implement the integer overflow checks in a much more
498        dynamic way, which I have now done. The artificial limitation on group
499        length has been removed - we now have only the limit on the total length of
500        the compiled pattern, which depends on the LINK_SIZE setting.
501    
502    10. Fixed a bug in the documentation for get/copy named substring when
503        duplicate names are permitted. If none of the named substrings are set, the
504        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
505        empty string.
506    
507    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
508        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
509        because the ] is interpreted as the first data character and the
510        terminating ] is not found. PCRE has been made compatible with Perl in this
511        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
512        cause memory overwriting.
513    
514    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
515        string has been matched (to stop an infinite loop). It was not recognizing
516        a conditional subpattern that could match an empty string if that
517        subpattern was within another subpattern. For example, it looped when
518        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
519        condition was not nested. This bug has been fixed.
520    
521    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
522        past the start of the subject in the presence of bytes with the top bit
523        set, for example "\x8aBCD".
524    
525    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
526        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
527    
528    14. Optimized (?!) to (*FAIL).
529    
530    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
531        This restricts code points to be within the range 0 to 0x10FFFF, excluding
532        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
533        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
534        does: it's just the validity check that is more restrictive.
535    
536    16. Inserted checks for integer overflows during escape sequence (backslash)
537        processing, and also fixed erroneous offset values for syntax errors during
538        backslash processing.
539    
540    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
541        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
542    
543    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
544        caused an overrun.
545    
546    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
547        something other than just ASCII characters) inside a group that had an
548        unlimited repeat caused a loop at compile time (while checking to see
549        whether the group could match an empty string).
550    
551    20. Debugging a pattern containing \p or \P could cause a crash. For example,
552        [\P{Any}] did so. (Error in the code for printing property names.)
553    
554    21. An orphan \E inside a character class could cause a crash.
555    
556    22. A repeated capturing bracket such as (A)? could cause a wild memory
557        reference during compilation.
558    
559    23. There are several functions in pcre_compile() that scan along a compiled
560        expression for various reasons (e.g. to see if it's fixed length for look
561        behind). There were bugs in these functions when a repeated \p or \P was
562        present in the pattern. These operators have additional parameters compared
563        with \d, etc, and these were not being taken into account when moving along
564        the compiled data. Specifically:
565    
566        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
567            length.
568    
569        (b) An item such as \pL+ within a repeated group could cause crashes or
570            loops.
571    
572        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
573            "reference to non-existent subpattern" error.
574    
575        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
576    
577    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
578        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
579    
580    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
581    
582    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
583        character were causing crashes (broken optimization).
584    
585    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
586        \p or \P) caused a compile-time loop.
587    
588    28. More problems have arisen in unanchored patterns when CRLF is a valid line
589        break. For example, the unstudied pattern [\r\n]A does not match the string
590        "\r\nA" because change 7.0/46 below moves the current point on by two
591        characters after failing to match at the start. However, the pattern \nA
592        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
593        the same is true. There doesn't seem any very clean way out of this, but
594        what I have chosen to do makes the common cases work: PCRE now takes note
595        of whether there can be an explicit match for \r or \n anywhere in the
596        pattern, and if so, 7.0/46 no longer applies. As part of this change,
597        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
598        pattern has explicit CR or LF references.
599    
600    29. Added (*CR) etc for changing newline setting at start of pattern.
601    
602    
603    Version 7.2 19-Jun-07
604  ---------------------  ---------------------
605    
606   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
# Line 21  Version 7.2 01-May-07 Line 620  Version 7.2 01-May-07
620      stack recursion. This gives a massive performance boost under BSD, but just      stack recursion. This gives a massive performance boost under BSD, but just
621      a small improvement under Linux. However, it saves one field in the frame      a small improvement under Linux. However, it saves one field in the frame
622      in all cases.      in all cases.
623    
624   6. Added more features from the forthcoming Perl 5.10:   6. Added more features from the forthcoming Perl 5.10:
625    
626      (a) (?-n) (where n is a string of digits) is a relative subroutine or      (a) (?-n) (where n is a string of digits) is a relative subroutine or
627          recursion call. It refers to the nth most recently opened parentheses.          recursion call. It refers to the nth most recently opened parentheses.
628    
629      (b) (?+n) is also a relative subroutine call; it refers to the nth next      (b) (?+n) is also a relative subroutine call; it refers to the nth next
630          to be opened parentheses.          to be opened parentheses.
631    
632      (c) Conditions that refer to capturing parentheses can be specified      (c) Conditions that refer to capturing parentheses can be specified
633          relatively, for example, (?(-2)... or (?(+3)...          relatively, for example, (?(-2)... or (?(+3)...
634    
635        (d) \K resets the start of the current match so that everything before
636            is not part of it.
637    
638        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
639    
640        (f) \g{name} is another synonym - part of Perl 5.10's unification of
641            reference syntax.
642    
643        (g) (?| introduces a group in which the numbering of parentheses in each
644            alternative starts with the same number.
645    
646        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
647    
648     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
649        PCRE_INFO_JCHANGED.
650    
651     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
652        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
653        for detecting groups that can match an empty string.
654    
655     9. A pattern with a very large number of alternatives (more than several
656        hundred) was running out of internal workspace during the pre-compile
657        phase, where pcre_compile() figures out how much memory will be needed. A
658        bit of new cunning has reduced the workspace needed for groups with
659        alternatives. The 1000-alternative test pattern now uses 12 bytes of
660        workspace instead of running out of the 4096 that are available.
661    
662    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
663    
664    11. Applied patch from Google to remove an optimization that didn't quite work.
665        The report of the bug said:
666    
667          pcrecpp::RE("a*").FullMatch("aaa") matches, while
668          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
669          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
670    
671    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
672        it matched the wrong number of bytes.
673    
674    
675  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
676  ---------------------  ---------------------

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