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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4    Version 7.8 25-Aug-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.
66    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
67        /^[^d]*?$/8 failed to match "abc".
69    16. Added a missing copyright notice to pcrecpp_internal.h.
71    17. Make it more clear in the documentation that values returned from
72        pcre_exec() in ovector are byte offsets, not character counts.
74    18. Tidied a few places to stop certain compilers from issuing warnings.
77    Version 7.7 07-May-08
78    ---------------------
80    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
81        a string to a long long, pretend we don't even have a long long." This is
82        done by checking for the strtoq, strtoll, and _strtoi64 functions.
84    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
85        pre-7.6 versions, which defined a global no_arg variable instead of putting
86        it in the RE class. (See also #8 below.)
88    3.  Remove a line of dead code, identified by coverity and reported by Nuno
89        Lopes.
91    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
93        (1) The include/exclude patterns were being applied to the whole pathnames
94            of files, instead of just to the final components.
96        (2) If there was more than one level of directory, the subdirectories were
97            skipped unless they satisfied the include/exclude conditions. This is
98            inconsistent with GNU grep (and could even be seen as contrary to the
99            pcregrep specification - which I improved to make it absolutely clear).
100            The action now is always to scan all levels of directory, and just
101            apply the include/exclude patterns to regular files.
103    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
104        --exclude_dir in the tests to avoid scanning .svn directories.
106    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
107        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
108        doesn't support NULs in patterns.
110    7.  Added some missing "const"s to declarations of static tables in
111        pcre_compile.c and pcre_dfa_exec.c.
113    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
114        caused by fix #2  above. (Subsequently also a second patch to fix the
115        first patch. And a third patch - this was a messy problem.)
117    9.  Applied Craig's patch to remove the use of push_back().
119    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
120        matching function regexec().
122    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
123        which, however, unlike Perl's \g{...}, are subroutine calls, not back
124        references. PCRE supports relative numbers with this syntax (I don't think
125        Oniguruma does).
127    12. Previously, a group with a zero repeat such as (...){0} was completely
128        omitted from the compiled regex. However, this means that if the group
129        was called as a subroutine from elsewhere in the pattern, things went wrong
130        (an internal error was given). Such groups are now left in the compiled
131        pattern, with a new opcode that causes them to be skipped at execution
132        time.
134    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
135        to the way PCRE behaves:
137        (a) A lone ] character is dis-allowed (Perl treats it as data).
139        (b) A back reference to an unmatched subpattern matches an empty string
140            (Perl fails the current match path).
142        (c) A data ] in a character class must be notated as \] because if the
143            first data character in a class is ], it defines an empty class. (In
144            Perl it is not possible to have an empty class.) The empty class []
145            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
146            The negative empty class [^] matches any one character, independently
147            of the DOTALL setting.
149    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
150        non-existent subpattern following a character class starting with ']' and
151        containing () gave an internal compiling error instead of "reference to
152        non-existent subpattern". Fortunately, when the pattern did exist, the
153        compiled code was correct. (When scanning forwards to check for the
154        existencd of the subpattern, it was treating the data ']' as terminating
155        the class, so got the count wrong. When actually compiling, the reference
156        was subsequently set up correctly.)
158    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
159        it was being rejected as not supported by pcre_dfa_exec(), even though
160        other assertions are supported. I have made pcre_dfa_exec() support
161        (*FAIL).
163    16. The implementation of 13c above involved the invention of a new opcode,
164        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
165        cannot be changed at match time, I realized I could make a small
166        improvement to matching performance by compiling OP_ALLANY instead of
167        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
168        on the OP_ANY path.
170    17. Compiling pcretest on Windows with readline support failed without the
171        following two fixes: (1) Make the unistd.h include conditional on
172        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
174    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
175        ncurses library to be included for pcretest when ReadLine support is
176        requested, but also to allow for it to be overridden. This patch came from
177        Daniel Bergström.
179    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
180        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
181        any errors with the current Unicode tables. Thanks to Peter Kankowski for
182        spotting this.
185    Version 7.6 28-Jan-08
186    ---------------------
188    1.  A character class containing a very large number of characters with
189        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
190        overflow.
192    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
193        HAVE_LONG_LONG is not defined.
195    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
196        bring them up to date and include new features. This patch includes:
198        - Fixed PH's badly added libz and libbz2 support.
199        - Fixed a problem with static linking.
200        - Added pcredemo. [But later removed - see 7 below.]
201        - Fixed dftables problem and added an option.
202        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
203            HAVE_LONG_LONG.
204        - Added readline support for pcretest.
205        - Added an listing of the option settings after cmake has run.
207    4.  A user submitted a patch to Makefile that makes it easy to create
208        "pcre.dll" under mingw when using Configure/Make. I added stuff to
209        Makefile.am that cause it to include this special target, without
210        affecting anything else. Note that the same mingw target plus all
211        the other distribution libraries and programs are now supported
212        when configuring with CMake (see 6 below) instead of with
213        Configure/Make.
215    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
216        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
217        exported in the Windows port". It has not yet been confirmed that the patch
218        solves the problem, but it does no harm.
220    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
221        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
222        with CMake, and also correct the comment about stack recursion.
224    7.  Remove the automatic building of pcredemo from the ./configure system and
225        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
226        of a program that users should build themselves after PCRE is installed, so
227        building it automatically is not really right. What is more, it gave
228        trouble in some build environments.
230    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
233    Version 7.5 10-Jan-08
234    ---------------------
236    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
237        values in parens when parsing an RE using the C++ wrapper."
239    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
240        Characters greater than 255 were excluded from the class instead of being
241        included.
243    3.  The same bug as (2) above applied to negated POSIX classes such as
244        [:^space:].
246    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
247        defined or documented. It seems to have been a typo for PCRE_STATIC, so
248        I have changed it.
250    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
251        first named subpattern) and a construct such as (?&a) would reference the
252        first named subpattern whose name started with "a" (in other words, the
253        length check was missing). Both these problems are fixed. "Subpattern name
254        expected" is now given for (?&) (a zero-length name), and this patch also
255        makes it give the same error for \k'' (previously it complained that that
256        was a reference to a non-existent subpattern).
258    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
259        this is right because (?- can be followed by option settings as well as by
260        digits. I have, however, made the messages clearer.
262    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
263        than the number used in the conditional) now cause a compile-time error.
264        This is actually not compatible with Perl, which accepts such patterns, but
265        treats the conditional as always being FALSE (as PCRE used to), but it
266        seems to me that giving a diagnostic is better.
268    8.  Change "alphameric" to the more common word "alphanumeric" in comments
269        and messages.
271    9.  Fix two occurrences of "backslash" in comments that should have been
272        "backspace".
274    10. Remove two redundant lines of code that can never be obeyed (their function
275        was moved elsewhere).
277    11. The program that makes PCRE's Unicode character property table had a bug
278        which caused it to generate incorrect table entries for sequences of
279        characters that have the same character type, but are in different scripts.
280        It amalgamated them into a single range, with the script of the first of
281        them. In other words, some characters were in the wrong script. There were
282        thirteen such cases, affecting characters in the following ranges:
284          U+002b0 - U+002c1
285          U+0060c - U+0060d
286          U+0061e - U+00612
287          U+0064b - U+0065e
288          U+0074d - U+0076d
289          U+01800 - U+01805
290          U+01d00 - U+01d77
291          U+01d9b - U+01dbf
292          U+0200b - U+0200f
293          U+030fc - U+030fe
294          U+03260 - U+0327f
295          U+0fb46 - U+0fbb1
296          U+10450 - U+1049d
298    12. The -o option (show only the matching part of a line) for pcregrep was not
299        compatible with GNU grep in that, if there was more than one match in a
300        line, it showed only the first of them. It now behaves in the same way as
301        GNU grep.
303    13. If the -o and -v options were combined for pcregrep, it printed a blank
304        line for every non-matching line. GNU grep prints nothing, and pcregrep now
305        does the same. The return code can be used to tell if there were any
306        non-matching lines.
308    14. Added --file-offsets and --line-offsets to pcregrep.
310    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
311        infinitely looping recursion. The bug was that positive lookaheads were not
312        being skipped when checking for a possible empty match (negative lookaheads
313        and both kinds of lookbehind were skipped).
315    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
316        inclusion of <windows.h> to before rather than after the definition of
317        INVALID_FILE_ATTRIBUTES (patch from David Byron).
319    17. Specifying a possessive quantifier with a specific limit for a Unicode
320        character property caused pcre_compile() to compile bad code, which led at
321        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
322        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
323        caused the error; without that there was no problem.
325    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
327    19. Added --enable-pcretest-libreadline.
329    20. In pcrecpp.cc, the variable 'count' was incremented twice in
330        RE::GlobalReplace(). As a result, the number of replacements returned was
331        double what it should be. I removed one of the increments, but Craig sent a
332        later patch that removed the other one (the right fix) and added unit tests
333        that check the return values (which was not done before).
335    21. Several CMake things:
337        (1) Arranged that, when cmake is used on Unix, the libraries end up with
338            the names libpcre and libpcreposix, not just pcre and pcreposix.
340        (2) The above change means that pcretest and pcregrep are now correctly
341            linked with the newly-built libraries, not previously installed ones.
345    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
346        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
347        UTF-8 newline character). The key issue is that the pattern starts .*;
348        this means that the match must be either at the beginning, or after a
349        newline. The bug was in the code for advancing after a failed match and
350        checking that the new position followed a newline. It was not taking
351        account of UTF-8 characters correctly.
353    23. PCRE was behaving differently from Perl in the way it recognized POSIX
354        character classes. PCRE was not treating the sequence [:...:] as a
355        character class unless the ... were all letters. Perl, however, seems to
356        allow any characters between [: and :], though of course it rejects as
357        unknown any "names" that contain non-letters, because all the known class
358        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
359        for example, whereas PCRE did not - it did not recognize a POSIX character
360        class. This seemed a bit dangerous, so the code has been changed to be
361        closer to Perl. The behaviour is not identical to Perl, because PCRE will
362        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
363        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
364        Perl does, and where it didn't before.
366    24. Rewrite so as to remove the single use of %n from pcregrep because in some
367        Windows environments %n is disabled by default.
370    Version 7.4 21-Sep-07
371    ---------------------
373    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
374        means that a class such as [\s] counted as "explicit reference to CR or
375        LF". That isn't really right - the whole point of the change was to try to
376        help when there was an actual mention of one of the two characters. So now
377        the change happens only if \r or \n (or a literal CR or LF) character is
378        encountered.
380    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
381        of both had grown to the point where there were only 3 bits left.
382        Fortunately, there was spare space in the data structure, and so I have
383        moved the internal flags into a new 16-bit field to free up more option
384        bits.
386    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
387        but did not set the internal JCHANGED flag - either of these is enough to
388        control the way the "get" function works - but the PCRE_INFO_JCHANGED
389        facility is supposed to tell if (?J) was ever used, so now (?J) at the
390        start sets both bits.
392    4.  Added options (at build time, compile time, exec time) to change \R from
393        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
395    5.  doc/pcresyntax.html was missing from the distribution.
397    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
398        compatibility, even though it is no longer used.
400    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
401        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
402        windows.h file is present (where different names are used). [This was
403        reversed later after testing - see 16 below.]
405    8.  Changed all #include <config.h> to #include "config.h". There were also
406        some further <pcre.h> cases that I changed to "pcre.h".
408    9.  When pcregrep was used with the --colour option, it missed the line ending
409        sequence off the lines that it output.
411    10. It was pointed out to me that arrays of string pointers cause lots of
412        relocations when a shared library is dynamically loaded. A technique of
413        using a single long string with a table of offsets can drastically reduce
414        these. I have refactored PCRE in four places to do this. The result is
415        dramatic:
417          Originally:                          290
418          After changing UCP table:            187
419          After changing error message table:   43
420          After changing table of "verbs"       36
421          After changing table of Posix names   22
423        Thanks to the folks working on Gregex for glib for this insight.
425    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
426        unicode-properties was also set.
428    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
430    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
431        checked only for CRLF.
433    14. Added casts to pcretest.c to avoid compiler warnings.
435    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
437    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
438        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
439        entirely. This removes changes made in 7 above.
441    17. The CMake files have been updated, and there is now more information about
442        building with CMake in the NON-UNIX-USE document.
445    Version 7.3 28-Aug-07
446    ---------------------
448     1. In the rejigging of the build system that eventually resulted in 7.1, the
449        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
450        brackets there is not right, since it causes compilers to look for an
451        installed pcre.h, not the version that is in the source that is being
452        compiled (which of course may be different). I have changed it back to:
454          #include "pcre.h"
456        I have a vague recollection that the change was concerned with compiling in
457        different directories, but in the new build system, that is taken care of
458        by the VPATH setting the Makefile.
460     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
461        when the subject happened to end in the byte 0x85 (e.g. if the last
462        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
463        characters but of course it shouldn't be taken as a newline when it is part
464        of another character. The bug was that, for an unlimited repeat of . in
465        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
466        characters when looking for a newline.
468     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
470     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
471        in debug output.
473     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
474        long printing in the pcrecpp unittest when running under MinGW.
476     6. ESC_K was left out of the EBCDIC table.
478     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
479        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
480        limit also applies to "virtual nesting" when a pattern is recursive, and in
481        this case 1000 isn't so big. I have been able to remove this limit at the
482        expense of backing off one optimization in certain circumstances. Normally,
483        when pcre_exec() would call its internal match() function recursively and
484        immediately return the result unconditionally, it uses a "tail recursion"
485        feature to save stack. However, when a subpattern that can match an empty
486        string has an unlimited repetition quantifier, it no longer makes this
487        optimization. That gives it a stack frame in which to save the data for
488        checking that an empty string has been matched. Previously this was taken
489        from the 1000-entry workspace that had been reserved. So now there is no
490        explicit limit, but more stack is used.
492     8. Applied Daniel's patches to solve problems with the import/export magic
493        syntax that is required for Windows, and which was going wrong for the
494        pcreposix and pcrecpp parts of the library. These were overlooked when this
495        problem was solved for the main library.
497     9. There were some crude static tests to avoid integer overflow when computing
498        the size of patterns that contain repeated groups with explicit upper
499        limits. As the maximum quantifier is 65535, the maximum group length was
500        set at 30,000 so that the product of these two numbers did not overflow a
501        32-bit integer. However, it turns out that people want to use groups that
502        are longer than 30,000 bytes (though not repeat them that many times).
503        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
504        made it possible to implement the integer overflow checks in a much more
505        dynamic way, which I have now done. The artificial limitation on group
506        length has been removed - we now have only the limit on the total length of
507        the compiled pattern, which depends on the LINK_SIZE setting.
509    10. Fixed a bug in the documentation for get/copy named substring when
510        duplicate names are permitted. If none of the named substrings are set, the
511        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
512        empty string.
514    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
515        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
516        because the ] is interpreted as the first data character and the
517        terminating ] is not found. PCRE has been made compatible with Perl in this
518        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
519        cause memory overwriting.
521    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
522        string has been matched (to stop an infinite loop). It was not recognizing
523        a conditional subpattern that could match an empty string if that
524        subpattern was within another subpattern. For example, it looped when
525        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
526        condition was not nested. This bug has been fixed.
528    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
529        past the start of the subject in the presence of bytes with the top bit
530        set, for example "\x8aBCD".
532    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
533        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
535    14. Optimized (?!) to (*FAIL).
537    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
538        This restricts code points to be within the range 0 to 0x10FFFF, excluding
539        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
540        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
541        does: it's just the validity check that is more restrictive.
543    16. Inserted checks for integer overflows during escape sequence (backslash)
544        processing, and also fixed erroneous offset values for syntax errors during
545        backslash processing.
547    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
548        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
550    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
551        caused an overrun.
553    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
554        something other than just ASCII characters) inside a group that had an
555        unlimited repeat caused a loop at compile time (while checking to see
556        whether the group could match an empty string).
558    20. Debugging a pattern containing \p or \P could cause a crash. For example,
559        [\P{Any}] did so. (Error in the code for printing property names.)
561    21. An orphan \E inside a character class could cause a crash.
563    22. A repeated capturing bracket such as (A)? could cause a wild memory
564        reference during compilation.
566    23. There are several functions in pcre_compile() that scan along a compiled
567        expression for various reasons (e.g. to see if it's fixed length for look
568        behind). There were bugs in these functions when a repeated \p or \P was
569        present in the pattern. These operators have additional parameters compared
570        with \d, etc, and these were not being taken into account when moving along
571        the compiled data. Specifically:
573        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
574            length.
576        (b) An item such as \pL+ within a repeated group could cause crashes or
577            loops.
579        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
580            "reference to non-existent subpattern" error.
582        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
584    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
585        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
587    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
589    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
590        character were causing crashes (broken optimization).
592    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
593        \p or \P) caused a compile-time loop.
595    28. More problems have arisen in unanchored patterns when CRLF is a valid line
596        break. For example, the unstudied pattern [\r\n]A does not match the string
597        "\r\nA" because change 7.0/46 below moves the current point on by two
598        characters after failing to match at the start. However, the pattern \nA
599        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
600        the same is true. There doesn't seem any very clean way out of this, but
601        what I have chosen to do makes the common cases work: PCRE now takes note
602        of whether there can be an explicit match for \r or \n anywhere in the
603        pattern, and if so, 7.0/46 no longer applies. As part of this change,
604        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
605        pattern has explicit CR or LF references.
607    29. Added (*CR) etc for changing newline setting at start of pattern.
610    Version 7.2 19-Jun-07
611    ---------------------
613     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
614        which is apparently normally available under Windows.
616     2. Re-jig the pcregrep tests with different newline settings in an attempt
617        to make them independent of the local environment's newline setting.
619     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
621     4. Some of the "internals" tests were previously cut out when the link size
622        was not 2, because the output contained actual offsets. The recent new
623        "Z" feature of pcretest means that these can be cut out, making the tests
624        usable with all link sizes.
626     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
627        stack recursion. This gives a massive performance boost under BSD, but just
628        a small improvement under Linux. However, it saves one field in the frame
629        in all cases.
631     6. Added more features from the forthcoming Perl 5.10:
633        (a) (?-n) (where n is a string of digits) is a relative subroutine or
634            recursion call. It refers to the nth most recently opened parentheses.
636        (b) (?+n) is also a relative subroutine call; it refers to the nth next
637            to be opened parentheses.
639        (c) Conditions that refer to capturing parentheses can be specified
640            relatively, for example, (?(-2)... or (?(+3)...
642        (d) \K resets the start of the current match so that everything before
643            is not part of it.
645        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
647        (f) \g{name} is another synonym - part of Perl 5.10's unification of
648            reference syntax.
650        (g) (?| introduces a group in which the numbering of parentheses in each
651            alternative starts with the same number.
653        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
655     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
658     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
659        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
660        for detecting groups that can match an empty string.
662     9. A pattern with a very large number of alternatives (more than several
663        hundred) was running out of internal workspace during the pre-compile
664        phase, where pcre_compile() figures out how much memory will be needed. A
665        bit of new cunning has reduced the workspace needed for groups with
666        alternatives. The 1000-alternative test pattern now uses 12 bytes of
667        workspace instead of running out of the 4096 that are available.
669    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
671    11. Applied patch from Google to remove an optimization that didn't quite work.
672        The report of the bug said:
674          pcrecpp::RE("a*").FullMatch("aaa") matches, while
675          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
676          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
678    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
679        it matched the wrong number of bytes.
682    Version 7.1 24-Apr-07
683    ---------------------
685     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
686        that is more "standard", making use of automake and other Autotools. There
687        is some re-arrangement of the files and adjustment of comments consequent
688        on this.
690     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
691        for recursive directory scanning broke on some systems because the files
692        are not scanned in any specific order and on different systems the order
693        was different. A call to "sort" has been inserted into RunGrepTest for the
694        approprate test as a short-term fix. In the longer term there may be an
695        alternative.
697     3. I had an email from Eric Raymond about problems translating some of PCRE's
698        man pages to HTML (despite the fact that I distribute HTML pages, some
699        people do their own conversions for various reasons). The problems
700        concerned the use of low-level troff macros .br and .in. I have therefore
701        removed all such uses from the man pages (some were redundant, some could
702        be replaced by .nf/.fi pairs). The 132html script that I use to generate
703        HTML has been updated to handle .nf/.fi and to complain if it encounters
704        .br or .in.
706     4. Updated comments in configure.ac that get placed in config.h.in and also
707        arranged for config.h to be included in the distribution, with the name
708        config.h.generic, for the benefit of those who have to compile without
709        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
711     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
712        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
713        makevp.bat for the current PCRE, using the additional files
714        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
716     6. A Windows user reported a minor discrepancy with test 2, which turned out
717        to be caused by a trailing space on an input line that had got lost in his
718        copy. The trailing space was an accident, so I've just removed it.
720     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
721        that is needed.
723     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
724        as "const" (a) because they are and (b) because it helps the PHP
725        maintainers who have recently made a script to detect big data structures
726        in the php code that should be moved to the .rodata section. I remembered
727        to update Builducptable as well, so it won't revert if ucptable.h is ever
728        re-created.
730     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
731        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
732        order to be able to cut out the UTF-8 tables in the latter when UTF-8
733        support is not required. This saves 1.5-2K of code, which is important in
734        some applications.
736        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
737        so as not to refer to the tables, even though these functions will never be
738        called when UTF-8 support is disabled. Otherwise there are problems with a
739        shared library.
741    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
743        (a) It was defining its arguments as char * instead of void *.
745        (b) It was assuming that all moves were upwards in memory; this was true
746            a long time ago when I wrote it, but is no longer the case.
748        The emulated memove() is provided for those environments that have neither
749        memmove() nor bcopy(). I didn't think anyone used it these days, but that
750        is clearly not the case, as these two bugs were recently reported.
752    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
753        and Detrail to create the HTML documentation, the .txt form of the man
754        pages, and it removes trailing spaces from listed files. It also creates
755        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
756        case, it wraps all the #defines with #ifndefs. This script should be run
757        before "make dist".
759    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
760        with Unicode property support.
762        (a) For a maximizing quantifier, if the two different cases of the
763            character were of different lengths in their UTF-8 codings (there are
764            some cases like this - I found 11), and the matching function had to
765            back up over a mixture of the two cases, it incorrectly assumed they
766            were both the same length.
768        (b) When PCRE was configured to use the heap rather than the stack for
769            recursion during matching, it was not correctly preserving the data for
770            the other case of a UTF-8 character when checking ahead for a match
771            while processing a minimizing repeat. If the check also involved
772            matching a wide character, but failed, corruption could cause an
773            erroneous result when trying to check for a repeat of the original
774            character.
776    13. Some tidying changes to the testing mechanism:
778        (a) The RunTest script now detects the internal link size and whether there
779            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
780            values substituted by "configure". (The RunGrepTest script already did
781            this for UTF-8.) The configure.ac script no longer substitutes the
782            relevant variables.
784        (b) The debugging options /B and /D in pcretest show the compiled bytecode
785            with length and offset values. This means that the output is different
786            for different internal link sizes. Test 2 is skipped for link sizes
787            other than 2 because of this, bypassing the problem. Unfortunately,
788            there was also a test in test 3 (the locale tests) that used /B and
789            failed for link sizes other than 2. Rather than cut the whole test out,
790            I have added a new /Z option to pcretest that replaces the length and
791            offset values with spaces. This is now used to make test 3 independent
792            of link size. (Test 2 will be tidied up later.)
794    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
795        segmentation fault instead of returning the appropriate error message.
797    15. In multiline mode when the newline sequence was set to "any", the pattern
798        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
799        This doesn't seem right; it now treats the CRLF combination as the line
800        ending, and so does not match in that case. It's only a pattern such as ^$
801        that would hit this one: something like ^ABC$ would have failed after \r
802        and then tried again after \r\n.
804    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
805        in an attempt to make files that differ only in their line terminators
806        compare equal. This works on Linux.
808    17. Under certain error circumstances pcregrep might try to free random memory
809        as it exited. This is now fixed, thanks to valgrind.
811    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
812        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
813        was because its rules for how to advance for /g after matching an empty
814        string at the end of a line did not allow for this case. They now check for
815        it specially.
817    20. pcretest is supposed to handle patterns and data of any length, by
818        extending its buffers when necessary. It was getting this wrong when the
819        buffer for a data line had to be extended.
821    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
822        CRLF as a newline sequence.
824    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
825        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
826        I have nevertheless tidied it up.
828    23. Added some casts to kill warnings from HP-UX ia64 compiler.
830    24. Added a man page for pcre-config.
833    Version 7.0 19-Dec-06
834    ---------------------
836     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
837        moving to gcc 4.1.1.
839     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
840        sys/time.h, which is documented as needed for this function. It doesn't
841        seem to matter on Linux, but it showed up on some releases of OS X.
843     3. It seems that there are systems where bytes whose values are greater than
844        127 match isprint() in the "C" locale. The "C" locale should be the
845        default when a C program starts up. In most systems, only ASCII printing
846        characters match isprint(). This difference caused the output from pcretest
847        to vary, making some of the tests fail. I have changed pcretest so that:
849        (a) When it is outputting text in the compiled version of a pattern, bytes
850            other than 32-126 are always shown as hex escapes.
852        (b) When it is outputting text that is a matched part of a subject string,
853            it does the same, unless a different locale has been set for the match
854            (using the /L modifier). In this case, it uses isprint() to decide.
856     4. Fixed a major bug that caused incorrect computation of the amount of memory
857        required for a compiled pattern when options that changed within the
858        pattern affected the logic of the preliminary scan that determines the
859        length. The relevant options are -x, and -i in UTF-8 mode. The result was
860        that the computed length was too small. The symptoms of this bug were
861        either the PCRE error "internal error: code overflow" from pcre_compile(),
862        or a glibc crash with a message such as "pcretest: free(): invalid next
863        size (fast)". Examples of patterns that provoked this bug (shown in
864        pcretest format) are:
866          /(?-x: )/x
867          /(?x)(?-x: \s*#\s*)/
868          /((?i)[\x{c0}])/8
869          /(?i:[\x{c0}])/8
871        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
872        is now done differently.
874     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
875        wrapper classes; (b) implement a new function in the C++ scanner that is
876        more efficient than the old way of doing things because it avoids levels of
877        recursion in the regex matching; (c) add a paragraph to the documentation
878        for the FullMatch() function.
880     6. The escape sequence \n was being treated as whatever was defined as
881        "newline". Not only was this contrary to the documentation, which states
882        that \n is character 10 (hex 0A), but it also went horribly wrong when
883        "newline" was defined as CRLF. This has been fixed.
885     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
886        was being set to -1 for the "end of line" case (supposedly a value that no
887        character can have). Though this value is never used (the check for end of
888        line is "zero bytes in current character"), it caused compiler complaints.
889        I've changed it to 0xffffffff.
891     8. In pcre_version.c, the version string was being built by a sequence of
892        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
893        string (as it is for production releases) called a macro with an empty
894        argument. The C standard says the result of this is undefined. The gcc
895        compiler treats it as an empty string (which was what was wanted) but it is
896        reported that Visual C gives an error. The source has been hacked around to
897        avoid this problem.
899     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
900        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
901        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
902        of them did).
904    10. Originally, pcretest opened its input and output without "b"; then I was
905        told that "b" was needed in some environments, so it was added for release
906        5.0 to both the input and output. (It makes no difference on Unix-like
907        systems.) Later I was told that it is wrong for the input on Windows. I've
908        now abstracted the modes into two macros, to make it easier to fiddle with
909        them, and removed "b" from the input mode under Windows.
911    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
913    12. Added -help and --help to pcretest as an official way of being reminded
914        of the options.
916    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
917        and pcrecpp.cc because they annoy compilers at high warning levels.
919    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
921    15. Fixed an occurrence of == in configure.ac that should have been = (shell
922        scripts are not C programs :-) and which was not noticed because it works
923        on Linux.
925    16. pcretest is supposed to handle any length of pattern and data line (as one
926        line or as a continued sequence of lines) by extending its input buffer if
927        necessary. This feature was broken for very long pattern lines, leading to
928        a string of junk being passed to pcre_compile() if the pattern was longer
929        than about 50K.
931    17. I have done a major re-factoring of the way pcre_compile() computes the
932        amount of memory needed for a compiled pattern. Previously, there was code
933        that made a preliminary scan of the pattern in order to do this. That was
934        OK when PCRE was new, but as the facilities have expanded, it has become
935        harder and harder to keep it in step with the real compile phase, and there
936        have been a number of bugs (see for example, 4 above). I have now found a
937        cunning way of running the real compile function in a "fake" mode that
938        enables it to compute how much memory it would need, while actually only
939        ever using a few hundred bytes of working memory and without too many
940        tests of the mode. This should make future maintenance and development
941        easier. A side effect of this work is that the limit of 200 on the nesting
942        depth of parentheses has been removed (though this was never a serious
943        limitation, I suspect). However, there is a downside: pcre_compile() now
944        runs more slowly than before (30% or more, depending on the pattern). I
945        hope this isn't a big issue. There is no effect on runtime performance.
947    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
948        newline (only possible for the last line of a file) and it was a
949        pattern that set a locale (followed by /Lsomething), pcretest crashed.
951    19. Added additional timing features to pcretest. (1) The -tm option now times
952        matching only, not compiling. (2) Both -t and -tm can be followed, as a
953        separate command line item, by a number that specifies the number of
954        repeats to use when timing. The default is 50000; this gives better
955        precision, but takes uncomfortably long for very large patterns.
957    20. Extended pcre_study() to be more clever in cases where a branch of a
958        subpattern has no definite first character. For example, (a*|b*)[cd] would
959        previously give no result from pcre_study(). Now it recognizes that the
960        first character must be a, b, c, or d.
962    21. There was an incorrect error "recursive call could loop indefinitely" if
963        a subpattern (or the entire pattern) that was being tested for matching an
964        empty string contained only one non-empty item after a nested subpattern.
965        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
966        incorrectly, because the \d was being skipped in the check.
968    22. The pcretest program now has a new pattern option /B and a command line
969        option -b, which is equivalent to adding /B to every pattern. This causes
970        it to show the compiled bytecode, without the additional information that
971        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
972        is the same as /B/I).
974    23. A new optimization is now able automatically to treat some sequences such
975        as a*b as a*+b. More specifically, if something simple (such as a character
976        or a simple class like \d) has an unlimited quantifier, and is followed by
977        something that cannot possibly match the quantified thing, the quantifier
978        is automatically "possessified".
980    24. A recursive reference to a subpattern whose number was greater than 39
981        went wrong under certain circumstances in UTF-8 mode. This bug could also
982        have affected the operation of pcre_study().
984    25. Realized that a little bit of performance could be had by replacing
985        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
987    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
989    27. Possessive quantifiers such as a++ were previously implemented by turning
990        them into atomic groups such as ($>a+). Now they have their own opcodes,
991        which improves performance. This includes the automatically created ones
992        from 23 above.
994    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
995        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
996        the first matched character to be a colon. This applied both to named and
997        numbered groups.
999    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1001    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1002        building PCRE on Windows easier, so I have included it in the distribution.
1004    31. There is now a check in pcretest against a ridiculously large number being
1005        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1006        loop, the loop is abandoned.
1008    32. Forward references to subpatterns in conditions such as (?(2)...) where
1009        subpattern 2 is defined later cause pcre_compile() to search forwards in
1010        the pattern for the relevant set of parentheses. This search went wrong
1011        when there were unescaped parentheses in a character class, parentheses
1012        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1014    33. "Subroutine" calls and backreferences were previously restricted to
1015        referencing subpatterns earlier in the regex. This restriction has now
1016        been removed.
1018    34. Added a number of extra features that are going to be in Perl 5.10. On the
1019        whole, these are just syntactic alternatives for features that PCRE had
1020        previously implemented using the Python syntax or my own invention. The
1021        other formats are all retained for compatibility.
1023        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1024            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1025            also .NET compatible.
1027        (b) A recursion or subroutine call to a named group can now be defined as
1028            (?&name) as well as (?P>name).
1030        (c) A backreference to a named group can now be defined as \k<name> or
1031            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1032            5.10, are also .NET compatible.
1034        (d) A conditional reference to a named group can now use the syntax
1035            (?(<name>) or (?('name') as well as (?(name).
1037        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1038            groups (named and numbered) that are never evaluated inline, but can be
1039            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1040            is always false. There may be only one alternative in such a group.
1042        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1043            as the simple (?(R). The condition is true only if the most recent
1044            recursion is that of the given number or name. It does not search out
1045            through the entire recursion stack.
1047        (g) The escape \gN or \g{N} has been added, where N is a positive or
1048            negative number, specifying an absolute or relative reference.
1050    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1051        some "unreachable code" warnings.
1053    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1054        things, this adds five new scripts.
1056    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1057        There were also incompatibilities regarding the handling of \Q..\E inside
1058        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1059        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1061    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1062        matches an empty string, and forcibly breaks the loop. There were bugs in
1063        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1064        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1065        separate and independent bugs (that affected different cases) have been
1066        fixed.
1068    39. Refactored the code to abolish the use of different opcodes for small
1069        capturing bracket numbers. This is a tidy that I avoided doing when I
1070        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1071        The new approach is not only tidier, it makes it possible to reduce the
1072        memory needed to fix the previous bug (38).
1074    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1075        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1076        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1077        mode.
1079    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1080        report.
1082    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1083        copy construction and assignment in the C++ wrapper.
1085    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1086        couple of bugs that could have given wrong results in the "--newline=crlf"
1087        case.
1089    44. Added a number of casts and did some reorganization of signed/unsigned int
1090        variables following suggestions from Dair Grant. Also renamed the variable
1091        "this" as "item" because it is a C++ keyword.
1093    45. Arranged for dftables to add
1095          #include "pcre_internal.h"
1097        to pcre_chartables.c because without it, gcc 4.x may remove the array
1098        definition from the final binary if PCRE is built into a static library and
1099        dead code stripping is activated.
1101    46. For an unanchored pattern, if a match attempt fails at the start of a
1102        newline sequence, and the newline setting is CRLF or ANY, and the next two
1103        characters are CRLF, advance by two characters instead of one.
1106    Version 6.7 04-Jul-06
1107    ---------------------
1109     1. In order to handle tests when input lines are enormously long, pcretest has
1110        been re-factored so that it automatically extends its buffers when
1111        necessary. The code is crude, but this _is_ just a test program. The
1112        default size has been increased from 32K to 50K.
1114     2. The code in pcre_study() was using the value of the re argument before
1115        testing it for NULL. (Of course, in any sensible call of the function, it
1116        won't be NULL.)
1118     3. The memmove() emulation function in pcre_internal.h, which is used on
1119        systems that lack both memmove() and bcopy() - that is, hardly ever -
1120        was missing a "static" storage class specifier.
1122     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1123        containing an extended class (one that cannot be represented by a bitmap
1124        because it contains high-valued characters or Unicode property items, e.g.
1125        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1126        pattern, but PCRE should not loop if you do not (it no longer does).
1127        [Detail: two cases were found: (a) a repeated subpattern containing an
1128        extended class; (b) a recursive reference to a subpattern that followed a
1129        previous extended class. It wasn't skipping over the extended class
1130        correctly when UTF-8 mode was not set.]
1132     5. A negated single-character class was not being recognized as fixed-length
1133        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1134        compile error "lookbehind assertion is not fixed length".
1136     6. The RunPerlTest auxiliary script was showing an unexpected difference
1137        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1138        write a Perl script that can interpret lines of an input file either as
1139        byte characters or as UTF-8, which is what "perltest" was being required to
1140        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1141        can't do is switch easily at run time between having the "use utf8;" pragma
1142        or not. In the end, I fudged it by using the RunPerlTest script to insert
1143        "use utf8;" explicitly for the UTF-8 tests.
1145     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1146        the end of the subject string, contrary to the documentation and to what
1147        Perl does. This was true of both matching functions. Now it matches only at
1148        the start of the subject and immediately after *internal* newlines.
1150     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1151        a pointer to an int instead of a pointer to an unsigned long int. This
1152        caused problems on 64-bit systems.
1154     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1155        instance of the 'standard' template library not being so standard".
1157    10. There was no check on the number of named subpatterns nor the maximum
1158        length of a subpattern name. The product of these values is used to compute
1159        the size of the memory block for a compiled pattern. By supplying a very
1160        long subpattern name and a large number of named subpatterns, the size
1161        computation could be caused to overflow. This is now prevented by limiting
1162        the length of names to 32 characters, and the number of named subpatterns
1163        to 10,000.
1165    11. Subpatterns that are repeated with specific counts have to be replicated in
1166        the compiled pattern. The size of memory for this was computed from the
1167        length of the subpattern and the repeat count. The latter is limited to
1168        65535, but there was no limit on the former, meaning that integer overflow
1169        could in principle occur. The compiled length of a repeated subpattern is
1170        now limited to 30,000 bytes in order to prevent this.
1172    12. Added the optional facility to have named substrings with the same name.
1174    13. Added the ability to use a named substring as a condition, using the
1175        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1176        are numbers (not recommended). Forward references are permitted.
1178    14. Added forward references in named backreferences (if you see what I mean).
1180    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1181        pattern could run off the end of the subject. For example, the pattern
1182        "(?s)(.{1,5})"8 did this with the subject "ab".
1184    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1185        PCRE_CASELESS was set when matching characters that were quantified with ?
1186        or *.
1188    17. A character class other than a single negated character that had a minimum
1189        but no maximum quantifier - for example [ab]{6,} - was not handled
1190        correctly by pce_dfa_exec(). It would match only one character.
1192    18. A valid (though odd) pattern that looked like a POSIX character
1193        class but used an invalid character after [ (for example [[,abc,]]) caused
1194        pcre_compile() to give the error "Failed: internal error: code overflow" or
1195        in some cases to crash with a glibc free() error. This could even happen if
1196        the pattern terminated after [[ but there just happened to be a sequence of
1197        letters, a binary zero, and a closing ] in the memory that followed.
1199    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1200        over the years. Originally (before any Unicode support), just the bottom 8
1201        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1202        output from "man perlunicode" includes this:
1204          The regular expression compiler produces polymorphic opcodes.  That
1205          is, the pattern adapts to the data and automatically switches to
1206          the Unicode character scheme when presented with Unicode data--or
1207          instead uses a traditional byte scheme when presented with byte
1208          data.
1210        Sadly, a wide octal escape does not cause a switch, and in a string with
1211        no other multibyte characters, these octal escapes are treated as before.
1212        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1213        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1214        Unicode string.
1216        I have not perpetrated such confusion in PCRE. Up till now, it took just
1217        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1218        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1219        translate to the appropriate multibyte character.
1221    29. Applied some refactoring to reduce the number of warnings from Microsoft
1222        and Borland compilers. This has included removing the fudge introduced
1223        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1224        a warning about an unused variable.
1226    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1227        characters since release 4.0, because Perl (from release 5.004) does not.
1228        [Or at least, is documented not to: some releases seem to be in conflict
1229        with the documentation.] However, when a pattern was studied with
1230        pcre_study() and all its branches started with \s, PCRE still included VT
1231        as a possible starting character. Of course, this did no harm; it just
1232        caused an unnecessary match attempt.
1234    22. Removed a now-redundant internal flag bit that recorded the fact that case
1235        dependency changed within the pattern. This was once needed for "required
1236        byte" processing, but is no longer used. This recovers a now-scarce options
1237        bit. Also moved the least significant internal flag bit to the most-
1238        significant bit of the word, which was not previously used (hangover from
1239        the days when it was an int rather than a uint) to free up another bit for
1240        the future.
1242    23. Added support for CRLF line endings as well as CR and LF. As well as the
1243        default being selectable at build time, it can now be changed at runtime
1244        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1245        specify that it is scanning data with non-default line endings.
1247    24. Changed the definition of CXXLINK to make it agree with the definition of
1248        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1250    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1251        recursions. This makes a big different to stack usage for some patterns.
1253    26. If a subpattern containing a named recursion or subroutine reference such
1254        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1255        the space required for the compiled pattern went wrong and gave too small a
1256        value. Depending on the environment, this could lead to "Failed: internal
1257        error: code overflow at offset 49" or "glibc detected double free or
1258        corruption" errors.
1260    27. Applied patches from Google (a) to support the new newline modes and (b) to
1261        advance over multibyte UTF-8 characters in GlobalReplace.
1263    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1264        difference for some implementation of PCRE in some Windows version.
1266    29. Added some extra testing facilities to pcretest:
1268        \q<number>   in a data line sets the "match limit" value
1269        \Q<number>   in a data line sets the "match recursion limt" value
1270        -S <number>  sets the stack size, where <number> is in megabytes
1272        The -S option isn't available for Windows.
1275  Version 6.6 06-Feb-06  Version 6.6 06-Feb-06
1276  ---------------------  ---------------------

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