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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.2 01-May-07  Version 8.0 02 Jul-08
5    ---------------------
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).
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
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.
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.
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.
30    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
32    7.  Added two (int) casts to pcregrep when printing the difference of two
33        pointers, in case they are 64-bit values.
35    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
36        test 2 if it fails.
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.
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.
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:
49          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
51        This potential security problem was recorded as CVE-2008-2371.
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.
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.
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.
67    Version 7.7 07-May-08
68    ---------------------
70    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
71        a string to a long long, pretend we don't even have a long long." This is
72        done by checking for the strtoq, strtoll, and _strtoi64 functions.
74    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
75        pre-7.6 versions, which defined a global no_arg variable instead of putting
76        it in the RE class. (See also #8 below.)
78    3.  Remove a line of dead code, identified by coverity and reported by Nuno
79        Lopes.
81    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
83        (1) The include/exclude patterns were being applied to the whole pathnames
84            of files, instead of just to the final components.
86        (2) If there was more than one level of directory, the subdirectories were
87            skipped unless they satisfied the include/exclude conditions. This is
88            inconsistent with GNU grep (and could even be seen as contrary to the
89            pcregrep specification - which I improved to make it absolutely clear).
90            The action now is always to scan all levels of directory, and just
91            apply the include/exclude patterns to regular files.
93    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
94        --exclude_dir in the tests to avoid scanning .svn directories.
96    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
97        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
98        doesn't support NULs in patterns.
100    7.  Added some missing "const"s to declarations of static tables in
101        pcre_compile.c and pcre_dfa_exec.c.
103    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
104        caused by fix #2  above. (Subsequently also a second patch to fix the
105        first patch. And a third patch - this was a messy problem.)
107    9.  Applied Craig's patch to remove the use of push_back().
109    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
110        matching function regexec().
112    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
113        which, however, unlike Perl's \g{...}, are subroutine calls, not back
114        references. PCRE supports relative numbers with this syntax (I don't think
115        Oniguruma does).
117    12. Previously, a group with a zero repeat such as (...){0} was completely
118        omitted from the compiled regex. However, this means that if the group
119        was called as a subroutine from elsewhere in the pattern, things went wrong
120        (an internal error was given). Such groups are now left in the compiled
121        pattern, with a new opcode that causes them to be skipped at execution
122        time.
124    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
125        to the way PCRE behaves:
127        (a) A lone ] character is dis-allowed (Perl treats it as data).
129        (b) A back reference to an unmatched subpattern matches an empty string
130            (Perl fails the current match path).
132        (c) A data ] in a character class must be notated as \] because if the
133            first data character in a class is ], it defines an empty class. (In
134            Perl it is not possible to have an empty class.) The empty class []
135            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
136            The negative empty class [^] matches any one character, independently
137            of the DOTALL setting.
139    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
140        non-existent subpattern following a character class starting with ']' and
141        containing () gave an internal compiling error instead of "reference to
142        non-existent subpattern". Fortunately, when the pattern did exist, the
143        compiled code was correct. (When scanning forwards to check for the
144        existencd of the subpattern, it was treating the data ']' as terminating
145        the class, so got the count wrong. When actually compiling, the reference
146        was subsequently set up correctly.)
148    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
149        it was being rejected as not supported by pcre_dfa_exec(), even though
150        other assertions are supported. I have made pcre_dfa_exec() support
151        (*FAIL).
153    16. The implementation of 13c above involved the invention of a new opcode,
154        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
155        cannot be changed at match time, I realized I could make a small
156        improvement to matching performance by compiling OP_ALLANY instead of
157        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
158        on the OP_ANY path.
160    17. Compiling pcretest on Windows with readline support failed without the
161        following two fixes: (1) Make the unistd.h include conditional on
162        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
164    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
165        ncurses library to be included for pcretest when ReadLine support is
166        requested, but also to allow for it to be overridden. This patch came from
167        Daniel Bergström.
169    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
170        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
171        any errors with the current Unicode tables. Thanks to Peter Kankowski for
172        spotting this.
175    Version 7.6 28-Jan-08
176    ---------------------
178    1.  A character class containing a very large number of characters with
179        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
180        overflow.
182    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
183        HAVE_LONG_LONG is not defined.
185    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
186        bring them up to date and include new features. This patch includes:
188        - Fixed PH's badly added libz and libbz2 support.
189        - Fixed a problem with static linking.
190        - Added pcredemo. [But later removed - see 7 below.]
191        - Fixed dftables problem and added an option.
192        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
193            HAVE_LONG_LONG.
194        - Added readline support for pcretest.
195        - Added an listing of the option settings after cmake has run.
197    4.  A user submitted a patch to Makefile that makes it easy to create
198        "pcre.dll" under mingw when using Configure/Make. I added stuff to
199        Makefile.am that cause it to include this special target, without
200        affecting anything else. Note that the same mingw target plus all
201        the other distribution libraries and programs are now supported
202        when configuring with CMake (see 6 below) instead of with
203        Configure/Make.
205    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
206        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
207        exported in the Windows port". It has not yet been confirmed that the patch
208        solves the problem, but it does no harm.
210    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
211        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
212        with CMake, and also correct the comment about stack recursion.
214    7.  Remove the automatic building of pcredemo from the ./configure system and
215        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
216        of a program that users should build themselves after PCRE is installed, so
217        building it automatically is not really right. What is more, it gave
218        trouble in some build environments.
220    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
223    Version 7.5 10-Jan-08
224    ---------------------
226    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
227        values in parens when parsing an RE using the C++ wrapper."
229    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
230        Characters greater than 255 were excluded from the class instead of being
231        included.
233    3.  The same bug as (2) above applied to negated POSIX classes such as
234        [:^space:].
236    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
237        defined or documented. It seems to have been a typo for PCRE_STATIC, so
238        I have changed it.
240    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
241        first named subpattern) and a construct such as (?&a) would reference the
242        first named subpattern whose name started with "a" (in other words, the
243        length check was missing). Both these problems are fixed. "Subpattern name
244        expected" is now given for (?&) (a zero-length name), and this patch also
245        makes it give the same error for \k'' (previously it complained that that
246        was a reference to a non-existent subpattern).
248    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
249        this is right because (?- can be followed by option settings as well as by
250        digits. I have, however, made the messages clearer.
252    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
253        than the number used in the conditional) now cause a compile-time error.
254        This is actually not compatible with Perl, which accepts such patterns, but
255        treats the conditional as always being FALSE (as PCRE used to), but it
256        seems to me that giving a diagnostic is better.
258    8.  Change "alphameric" to the more common word "alphanumeric" in comments
259        and messages.
261    9.  Fix two occurrences of "backslash" in comments that should have been
262        "backspace".
264    10. Remove two redundant lines of code that can never be obeyed (their function
265        was moved elsewhere).
267    11. The program that makes PCRE's Unicode character property table had a bug
268        which caused it to generate incorrect table entries for sequences of
269        characters that have the same character type, but are in different scripts.
270        It amalgamated them into a single range, with the script of the first of
271        them. In other words, some characters were in the wrong script. There were
272        thirteen such cases, affecting characters in the following ranges:
274          U+002b0 - U+002c1
275          U+0060c - U+0060d
276          U+0061e - U+00612
277          U+0064b - U+0065e
278          U+0074d - U+0076d
279          U+01800 - U+01805
280          U+01d00 - U+01d77
281          U+01d9b - U+01dbf
282          U+0200b - U+0200f
283          U+030fc - U+030fe
284          U+03260 - U+0327f
285          U+0fb46 - U+0fbb1
286          U+10450 - U+1049d
288    12. The -o option (show only the matching part of a line) for pcregrep was not
289        compatible with GNU grep in that, if there was more than one match in a
290        line, it showed only the first of them. It now behaves in the same way as
291        GNU grep.
293    13. If the -o and -v options were combined for pcregrep, it printed a blank
294        line for every non-matching line. GNU grep prints nothing, and pcregrep now
295        does the same. The return code can be used to tell if there were any
296        non-matching lines.
298    14. Added --file-offsets and --line-offsets to pcregrep.
300    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
301        infinitely looping recursion. The bug was that positive lookaheads were not
302        being skipped when checking for a possible empty match (negative lookaheads
303        and both kinds of lookbehind were skipped).
305    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
306        inclusion of <windows.h> to before rather than after the definition of
307        INVALID_FILE_ATTRIBUTES (patch from David Byron).
309    17. Specifying a possessive quantifier with a specific limit for a Unicode
310        character property caused pcre_compile() to compile bad code, which led at
311        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
312        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
313        caused the error; without that there was no problem.
315    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
317    19. Added --enable-pcretest-libreadline.
319    20. In pcrecpp.cc, the variable 'count' was incremented twice in
320        RE::GlobalReplace(). As a result, the number of replacements returned was
321        double what it should be. I removed one of the increments, but Craig sent a
322        later patch that removed the other one (the right fix) and added unit tests
323        that check the return values (which was not done before).
325    21. Several CMake things:
327        (1) Arranged that, when cmake is used on Unix, the libraries end up with
328            the names libpcre and libpcreposix, not just pcre and pcreposix.
330        (2) The above change means that pcretest and pcregrep are now correctly
331            linked with the newly-built libraries, not previously installed ones.
335    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
336        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
337        UTF-8 newline character). The key issue is that the pattern starts .*;
338        this means that the match must be either at the beginning, or after a
339        newline. The bug was in the code for advancing after a failed match and
340        checking that the new position followed a newline. It was not taking
341        account of UTF-8 characters correctly.
343    23. PCRE was behaving differently from Perl in the way it recognized POSIX
344        character classes. PCRE was not treating the sequence [:...:] as a
345        character class unless the ... were all letters. Perl, however, seems to
346        allow any characters between [: and :], though of course it rejects as
347        unknown any "names" that contain non-letters, because all the known class
348        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
349        for example, whereas PCRE did not - it did not recognize a POSIX character
350        class. This seemed a bit dangerous, so the code has been changed to be
351        closer to Perl. The behaviour is not identical to Perl, because PCRE will
352        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
353        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
354        Perl does, and where it didn't before.
356    24. Rewrite so as to remove the single use of %n from pcregrep because in some
357        Windows environments %n is disabled by default.
360    Version 7.4 21-Sep-07
361    ---------------------
363    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
364        means that a class such as [\s] counted as "explicit reference to CR or
365        LF". That isn't really right - the whole point of the change was to try to
366        help when there was an actual mention of one of the two characters. So now
367        the change happens only if \r or \n (or a literal CR or LF) character is
368        encountered.
370    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
371        of both had grown to the point where there were only 3 bits left.
372        Fortunately, there was spare space in the data structure, and so I have
373        moved the internal flags into a new 16-bit field to free up more option
374        bits.
376    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
377        but did not set the internal JCHANGED flag - either of these is enough to
378        control the way the "get" function works - but the PCRE_INFO_JCHANGED
379        facility is supposed to tell if (?J) was ever used, so now (?J) at the
380        start sets both bits.
382    4.  Added options (at build time, compile time, exec time) to change \R from
383        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
385    5.  doc/pcresyntax.html was missing from the distribution.
387    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
388        compatibility, even though it is no longer used.
390    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
391        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
392        windows.h file is present (where different names are used). [This was
393        reversed later after testing - see 16 below.]
395    8.  Changed all #include <config.h> to #include "config.h". There were also
396        some further <pcre.h> cases that I changed to "pcre.h".
398    9.  When pcregrep was used with the --colour option, it missed the line ending
399        sequence off the lines that it output.
401    10. It was pointed out to me that arrays of string pointers cause lots of
402        relocations when a shared library is dynamically loaded. A technique of
403        using a single long string with a table of offsets can drastically reduce
404        these. I have refactored PCRE in four places to do this. The result is
405        dramatic:
407          Originally:                          290
408          After changing UCP table:            187
409          After changing error message table:   43
410          After changing table of "verbs"       36
411          After changing table of Posix names   22
413        Thanks to the folks working on Gregex for glib for this insight.
415    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
416        unicode-properties was also set.
418    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
420    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
421        checked only for CRLF.
423    14. Added casts to pcretest.c to avoid compiler warnings.
425    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
427    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
428        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
429        entirely. This removes changes made in 7 above.
431    17. The CMake files have been updated, and there is now more information about
432        building with CMake in the NON-UNIX-USE document.
435    Version 7.3 28-Aug-07
436    ---------------------
438     1. In the rejigging of the build system that eventually resulted in 7.1, the
439        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
440        brackets there is not right, since it causes compilers to look for an
441        installed pcre.h, not the version that is in the source that is being
442        compiled (which of course may be different). I have changed it back to:
444          #include "pcre.h"
446        I have a vague recollection that the change was concerned with compiling in
447        different directories, but in the new build system, that is taken care of
448        by the VPATH setting the Makefile.
450     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
451        when the subject happened to end in the byte 0x85 (e.g. if the last
452        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
453        characters but of course it shouldn't be taken as a newline when it is part
454        of another character. The bug was that, for an unlimited repeat of . in
455        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
456        characters when looking for a newline.
458     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
460     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
461        in debug output.
463     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
464        long printing in the pcrecpp unittest when running under MinGW.
466     6. ESC_K was left out of the EBCDIC table.
468     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
469        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
470        limit also applies to "virtual nesting" when a pattern is recursive, and in
471        this case 1000 isn't so big. I have been able to remove this limit at the
472        expense of backing off one optimization in certain circumstances. Normally,
473        when pcre_exec() would call its internal match() function recursively and
474        immediately return the result unconditionally, it uses a "tail recursion"
475        feature to save stack. However, when a subpattern that can match an empty
476        string has an unlimited repetition quantifier, it no longer makes this
477        optimization. That gives it a stack frame in which to save the data for
478        checking that an empty string has been matched. Previously this was taken
479        from the 1000-entry workspace that had been reserved. So now there is no
480        explicit limit, but more stack is used.
482     8. Applied Daniel's patches to solve problems with the import/export magic
483        syntax that is required for Windows, and which was going wrong for the
484        pcreposix and pcrecpp parts of the library. These were overlooked when this
485        problem was solved for the main library.
487     9. There were some crude static tests to avoid integer overflow when computing
488        the size of patterns that contain repeated groups with explicit upper
489        limits. As the maximum quantifier is 65535, the maximum group length was
490        set at 30,000 so that the product of these two numbers did not overflow a
491        32-bit integer. However, it turns out that people want to use groups that
492        are longer than 30,000 bytes (though not repeat them that many times).
493        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
494        made it possible to implement the integer overflow checks in a much more
495        dynamic way, which I have now done. The artificial limitation on group
496        length has been removed - we now have only the limit on the total length of
497        the compiled pattern, which depends on the LINK_SIZE setting.
499    10. Fixed a bug in the documentation for get/copy named substring when
500        duplicate names are permitted. If none of the named substrings are set, the
501        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
502        empty string.
504    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
505        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
506        because the ] is interpreted as the first data character and the
507        terminating ] is not found. PCRE has been made compatible with Perl in this
508        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
509        cause memory overwriting.
511    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
512        string has been matched (to stop an infinite loop). It was not recognizing
513        a conditional subpattern that could match an empty string if that
514        subpattern was within another subpattern. For example, it looped when
515        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
516        condition was not nested. This bug has been fixed.
518    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
519        past the start of the subject in the presence of bytes with the top bit
520        set, for example "\x8aBCD".
522    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
523        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
525    14. Optimized (?!) to (*FAIL).
527    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
528        This restricts code points to be within the range 0 to 0x10FFFF, excluding
529        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
530        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
531        does: it's just the validity check that is more restrictive.
533    16. Inserted checks for integer overflows during escape sequence (backslash)
534        processing, and also fixed erroneous offset values for syntax errors during
535        backslash processing.
537    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
538        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
540    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
541        caused an overrun.
543    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
544        something other than just ASCII characters) inside a group that had an
545        unlimited repeat caused a loop at compile time (while checking to see
546        whether the group could match an empty string).
548    20. Debugging a pattern containing \p or \P could cause a crash. For example,
549        [\P{Any}] did so. (Error in the code for printing property names.)
551    21. An orphan \E inside a character class could cause a crash.
553    22. A repeated capturing bracket such as (A)? could cause a wild memory
554        reference during compilation.
556    23. There are several functions in pcre_compile() that scan along a compiled
557        expression for various reasons (e.g. to see if it's fixed length for look
558        behind). There were bugs in these functions when a repeated \p or \P was
559        present in the pattern. These operators have additional parameters compared
560        with \d, etc, and these were not being taken into account when moving along
561        the compiled data. Specifically:
563        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
564            length.
566        (b) An item such as \pL+ within a repeated group could cause crashes or
567            loops.
569        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
570            "reference to non-existent subpattern" error.
572        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
574    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
575        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
577    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
579    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
580        character were causing crashes (broken optimization).
582    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
583        \p or \P) caused a compile-time loop.
585    28. More problems have arisen in unanchored patterns when CRLF is a valid line
586        break. For example, the unstudied pattern [\r\n]A does not match the string
587        "\r\nA" because change 7.0/46 below moves the current point on by two
588        characters after failing to match at the start. However, the pattern \nA
589        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
590        the same is true. There doesn't seem any very clean way out of this, but
591        what I have chosen to do makes the common cases work: PCRE now takes note
592        of whether there can be an explicit match for \r or \n anywhere in the
593        pattern, and if so, 7.0/46 no longer applies. As part of this change,
594        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
595        pattern has explicit CR or LF references.
597    29. Added (*CR) etc for changing newline setting at start of pattern.
600    Version 7.2 19-Jun-07
601  ---------------------  ---------------------
603   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 617  Version 7.2 01-May-07
617      stack recursion. This gives a massive performance boost under BSD, but just      stack recursion. This gives a massive performance boost under BSD, but just
618      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
619      in all cases.      in all cases.
621   6. Added more features from the forthcoming Perl 5.10:   6. Added more features from the forthcoming Perl 5.10:
623      (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
624          recursion call. It refers to the nth most recently opened parentheses.          recursion call. It refers to the nth most recently opened parentheses.
626      (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
627          to be opened parentheses.          to be opened parentheses.
629      (c) Conditions that refer to capturing parentheses can be specified      (c) Conditions that refer to capturing parentheses can be specified
630          relatively, for example, (?(-2)... or (?(+3)...          relatively, for example, (?(-2)... or (?(+3)...
632      (d) \K resets the start of the current match so that everything before      (d) \K resets the start of the current match so that everything before
633          is not part of it.          is not part of it.
635        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
637        (f) \g{name} is another synonym - part of Perl 5.10's unification of
638            reference syntax.
640        (g) (?| introduces a group in which the numbering of parentheses in each
641            alternative starts with the same number.
643        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
645     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
648     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
649        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
650        for detecting groups that can match an empty string.
652     9. A pattern with a very large number of alternatives (more than several
653        hundred) was running out of internal workspace during the pre-compile
654        phase, where pcre_compile() figures out how much memory will be needed. A
655        bit of new cunning has reduced the workspace needed for groups with
656        alternatives. The 1000-alternative test pattern now uses 12 bytes of
657        workspace instead of running out of the 4096 that are available.
659    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
661    11. Applied patch from Google to remove an optimization that didn't quite work.
662        The report of the bug said:
664          pcrecpp::RE("a*").FullMatch("aaa") matches, while
665          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
666          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
668    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
669        it matched the wrong number of bytes.
672  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07

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