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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 368 by ph10, Sun Aug 24 16:25:20 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.8 25-Aug-08
5    ---------------------
6    
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
13    
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
16    
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
20    
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
24    
25    5.  In pcretest, an escape such as \x{de} in the data was always generating
26        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28        truncation.
29    
30    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
31    
32    7.  Added two (int) casts to pcregrep when printing the difference of two
33        pointers, in case they are 64-bit values.
34    
35    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
36        test 2 if it fails.
37    
38    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
39        and a #define of that name to empty if it is not externally set. This is to
40        allow users of MSVC to set it if necessary.
41    
42    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
43        the convenience functions in the pcre_get.c source file.
44    
45    11. An option change at the start of a pattern that had top-level alternatives
46        could cause overwriting and/or a crash. This command provoked a crash in
47        some environments:
48    
49          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
50    
51        This potential security problem was recorded as CVE-2008-2371.
52    
53    12. For a pattern where the match had to start at the beginning or immediately
54        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
55        pcre_dfa_exec() could read past the end of the passed subject if there was
56        no match. To help with detecting such bugs (e.g. with valgrind), I modified
57        pcretest so that it places the subject at the end of its malloc-ed buffer.
58    
59    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
60        exec() might read past the end of the data buffer in UTF-8 mode.
61    
62    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
63        the data contained the byte 0x85 as part of a UTF-8 character within its
64        first line. This applied both to normal and DFA matching.
65    
66    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
67        /^[^d]*?$/8 failed to match "abc".
68    
69    16. Added a missing copyright notice to pcrecpp_internal.h.
70    
71    17. Make it more clear in the documentation that values returned from
72        pcre_exec() in ovector are byte offsets, not character counts.
73    
74    
75    Version 7.7 07-May-08
76    ---------------------
77    
78    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
79        a string to a long long, pretend we don't even have a long long." This is
80        done by checking for the strtoq, strtoll, and _strtoi64 functions.
81    
82    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
83        pre-7.6 versions, which defined a global no_arg variable instead of putting
84        it in the RE class. (See also #8 below.)
85    
86    3.  Remove a line of dead code, identified by coverity and reported by Nuno
87        Lopes.
88    
89    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
90    
91        (1) The include/exclude patterns were being applied to the whole pathnames
92            of files, instead of just to the final components.
93    
94        (2) If there was more than one level of directory, the subdirectories were
95            skipped unless they satisfied the include/exclude conditions. This is
96            inconsistent with GNU grep (and could even be seen as contrary to the
97            pcregrep specification - which I improved to make it absolutely clear).
98            The action now is always to scan all levels of directory, and just
99            apply the include/exclude patterns to regular files.
100    
101    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
102        --exclude_dir in the tests to avoid scanning .svn directories.
103    
104    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
105        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
106        doesn't support NULs in patterns.
107    
108    7.  Added some missing "const"s to declarations of static tables in
109        pcre_compile.c and pcre_dfa_exec.c.
110    
111    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
112        caused by fix #2  above. (Subsequently also a second patch to fix the
113        first patch. And a third patch - this was a messy problem.)
114    
115    9.  Applied Craig's patch to remove the use of push_back().
116    
117    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
118        matching function regexec().
119    
120    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
121        which, however, unlike Perl's \g{...}, are subroutine calls, not back
122        references. PCRE supports relative numbers with this syntax (I don't think
123        Oniguruma does).
124    
125    12. Previously, a group with a zero repeat such as (...){0} was completely
126        omitted from the compiled regex. However, this means that if the group
127        was called as a subroutine from elsewhere in the pattern, things went wrong
128        (an internal error was given). Such groups are now left in the compiled
129        pattern, with a new opcode that causes them to be skipped at execution
130        time.
131    
132    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
133        to the way PCRE behaves:
134    
135        (a) A lone ] character is dis-allowed (Perl treats it as data).
136    
137        (b) A back reference to an unmatched subpattern matches an empty string
138            (Perl fails the current match path).
139    
140        (c) A data ] in a character class must be notated as \] because if the
141            first data character in a class is ], it defines an empty class. (In
142            Perl it is not possible to have an empty class.) The empty class []
143            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
144            The negative empty class [^] matches any one character, independently
145            of the DOTALL setting.
146    
147    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
148        non-existent subpattern following a character class starting with ']' and
149        containing () gave an internal compiling error instead of "reference to
150        non-existent subpattern". Fortunately, when the pattern did exist, the
151        compiled code was correct. (When scanning forwards to check for the
152        existencd of the subpattern, it was treating the data ']' as terminating
153        the class, so got the count wrong. When actually compiling, the reference
154        was subsequently set up correctly.)
155    
156    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
157        it was being rejected as not supported by pcre_dfa_exec(), even though
158        other assertions are supported. I have made pcre_dfa_exec() support
159        (*FAIL).
160    
161    16. The implementation of 13c above involved the invention of a new opcode,
162        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
163        cannot be changed at match time, I realized I could make a small
164        improvement to matching performance by compiling OP_ALLANY instead of
165        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
166        on the OP_ANY path.
167    
168    17. Compiling pcretest on Windows with readline support failed without the
169        following two fixes: (1) Make the unistd.h include conditional on
170        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
171    
172    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
173        ncurses library to be included for pcretest when ReadLine support is
174        requested, but also to allow for it to be overridden. This patch came from
175        Daniel Bergström.
176    
177    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
178        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
179        any errors with the current Unicode tables. Thanks to Peter Kankowski for
180        spotting this.
181    
182    
183    Version 7.6 28-Jan-08
184    ---------------------
185    
186    1.  A character class containing a very large number of characters with
187        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
188        overflow.
189    
190    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
191        HAVE_LONG_LONG is not defined.
192    
193    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
194        bring them up to date and include new features. This patch includes:
195    
196        - Fixed PH's badly added libz and libbz2 support.
197        - Fixed a problem with static linking.
198        - Added pcredemo. [But later removed - see 7 below.]
199        - Fixed dftables problem and added an option.
200        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
201            HAVE_LONG_LONG.
202        - Added readline support for pcretest.
203        - Added an listing of the option settings after cmake has run.
204    
205    4.  A user submitted a patch to Makefile that makes it easy to create
206        "pcre.dll" under mingw when using Configure/Make. I added stuff to
207        Makefile.am that cause it to include this special target, without
208        affecting anything else. Note that the same mingw target plus all
209        the other distribution libraries and programs are now supported
210        when configuring with CMake (see 6 below) instead of with
211        Configure/Make.
212    
213    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
214        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
215        exported in the Windows port". It has not yet been confirmed that the patch
216        solves the problem, but it does no harm.
217    
218    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
219        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
220        with CMake, and also correct the comment about stack recursion.
221    
222    7.  Remove the automatic building of pcredemo from the ./configure system and
223        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
224        of a program that users should build themselves after PCRE is installed, so
225        building it automatically is not really right. What is more, it gave
226        trouble in some build environments.
227    
228    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
229    
230    
231    Version 7.5 10-Jan-08
232    ---------------------
233    
234    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
235        values in parens when parsing an RE using the C++ wrapper."
236    
237    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
238        Characters greater than 255 were excluded from the class instead of being
239        included.
240    
241    3.  The same bug as (2) above applied to negated POSIX classes such as
242        [:^space:].
243    
244    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
245        defined or documented. It seems to have been a typo for PCRE_STATIC, so
246        I have changed it.
247    
248    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
249        first named subpattern) and a construct such as (?&a) would reference the
250        first named subpattern whose name started with "a" (in other words, the
251        length check was missing). Both these problems are fixed. "Subpattern name
252        expected" is now given for (?&) (a zero-length name), and this patch also
253        makes it give the same error for \k'' (previously it complained that that
254        was a reference to a non-existent subpattern).
255    
256    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
257        this is right because (?- can be followed by option settings as well as by
258        digits. I have, however, made the messages clearer.
259    
260    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
261        than the number used in the conditional) now cause a compile-time error.
262        This is actually not compatible with Perl, which accepts such patterns, but
263        treats the conditional as always being FALSE (as PCRE used to), but it
264        seems to me that giving a diagnostic is better.
265    
266    8.  Change "alphameric" to the more common word "alphanumeric" in comments
267        and messages.
268    
269    9.  Fix two occurrences of "backslash" in comments that should have been
270        "backspace".
271    
272    10. Remove two redundant lines of code that can never be obeyed (their function
273        was moved elsewhere).
274    
275    11. The program that makes PCRE's Unicode character property table had a bug
276        which caused it to generate incorrect table entries for sequences of
277        characters that have the same character type, but are in different scripts.
278        It amalgamated them into a single range, with the script of the first of
279        them. In other words, some characters were in the wrong script. There were
280        thirteen such cases, affecting characters in the following ranges:
281    
282          U+002b0 - U+002c1
283          U+0060c - U+0060d
284          U+0061e - U+00612
285          U+0064b - U+0065e
286          U+0074d - U+0076d
287          U+01800 - U+01805
288          U+01d00 - U+01d77
289          U+01d9b - U+01dbf
290          U+0200b - U+0200f
291          U+030fc - U+030fe
292          U+03260 - U+0327f
293          U+0fb46 - U+0fbb1
294          U+10450 - U+1049d
295    
296    12. The -o option (show only the matching part of a line) for pcregrep was not
297        compatible with GNU grep in that, if there was more than one match in a
298        line, it showed only the first of them. It now behaves in the same way as
299        GNU grep.
300    
301    13. If the -o and -v options were combined for pcregrep, it printed a blank
302        line for every non-matching line. GNU grep prints nothing, and pcregrep now
303        does the same. The return code can be used to tell if there were any
304        non-matching lines.
305    
306    14. Added --file-offsets and --line-offsets to pcregrep.
307    
308    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
309        infinitely looping recursion. The bug was that positive lookaheads were not
310        being skipped when checking for a possible empty match (negative lookaheads
311        and both kinds of lookbehind were skipped).
312    
313    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
314        inclusion of <windows.h> to before rather than after the definition of
315        INVALID_FILE_ATTRIBUTES (patch from David Byron).
316    
317    17. Specifying a possessive quantifier with a specific limit for a Unicode
318        character property caused pcre_compile() to compile bad code, which led at
319        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
320        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
321        caused the error; without that there was no problem.
322    
323    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
324    
325    19. Added --enable-pcretest-libreadline.
326    
327    20. In pcrecpp.cc, the variable 'count' was incremented twice in
328        RE::GlobalReplace(). As a result, the number of replacements returned was
329        double what it should be. I removed one of the increments, but Craig sent a
330        later patch that removed the other one (the right fix) and added unit tests
331        that check the return values (which was not done before).
332    
333    21. Several CMake things:
334    
335        (1) Arranged that, when cmake is used on Unix, the libraries end up with
336            the names libpcre and libpcreposix, not just pcre and pcreposix.
337    
338        (2) The above change means that pcretest and pcregrep are now correctly
339            linked with the newly-built libraries, not previously installed ones.
340    
341        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
342    
343    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
344        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
345        UTF-8 newline character). The key issue is that the pattern starts .*;
346        this means that the match must be either at the beginning, or after a
347        newline. The bug was in the code for advancing after a failed match and
348        checking that the new position followed a newline. It was not taking
349        account of UTF-8 characters correctly.
350    
351    23. PCRE was behaving differently from Perl in the way it recognized POSIX
352        character classes. PCRE was not treating the sequence [:...:] as a
353        character class unless the ... were all letters. Perl, however, seems to
354        allow any characters between [: and :], though of course it rejects as
355        unknown any "names" that contain non-letters, because all the known class
356        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
357        for example, whereas PCRE did not - it did not recognize a POSIX character
358        class. This seemed a bit dangerous, so the code has been changed to be
359        closer to Perl. The behaviour is not identical to Perl, because PCRE will
360        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
361        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
362        Perl does, and where it didn't before.
363    
364    24. Rewrite so as to remove the single use of %n from pcregrep because in some
365        Windows environments %n is disabled by default.
366    
367    
368    Version 7.4 21-Sep-07
369    ---------------------
370    
371    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
372        means that a class such as [\s] counted as "explicit reference to CR or
373        LF". That isn't really right - the whole point of the change was to try to
374        help when there was an actual mention of one of the two characters. So now
375        the change happens only if \r or \n (or a literal CR or LF) character is
376        encountered.
377    
378    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
379        of both had grown to the point where there were only 3 bits left.
380        Fortunately, there was spare space in the data structure, and so I have
381        moved the internal flags into a new 16-bit field to free up more option
382        bits.
383    
384    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
385        but did not set the internal JCHANGED flag - either of these is enough to
386        control the way the "get" function works - but the PCRE_INFO_JCHANGED
387        facility is supposed to tell if (?J) was ever used, so now (?J) at the
388        start sets both bits.
389    
390    4.  Added options (at build time, compile time, exec time) to change \R from
391        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
392    
393    5.  doc/pcresyntax.html was missing from the distribution.
394    
395    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
396        compatibility, even though it is no longer used.
397    
398    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
399        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
400        windows.h file is present (where different names are used). [This was
401        reversed later after testing - see 16 below.]
402    
403    8.  Changed all #include <config.h> to #include "config.h". There were also
404        some further <pcre.h> cases that I changed to "pcre.h".
405    
406    9.  When pcregrep was used with the --colour option, it missed the line ending
407        sequence off the lines that it output.
408    
409    10. It was pointed out to me that arrays of string pointers cause lots of
410        relocations when a shared library is dynamically loaded. A technique of
411        using a single long string with a table of offsets can drastically reduce
412        these. I have refactored PCRE in four places to do this. The result is
413        dramatic:
414    
415          Originally:                          290
416          After changing UCP table:            187
417          After changing error message table:   43
418          After changing table of "verbs"       36
419          After changing table of Posix names   22
420    
421        Thanks to the folks working on Gregex for glib for this insight.
422    
423    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
424        unicode-properties was also set.
425    
426    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
427    
428    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
429        checked only for CRLF.
430    
431    14. Added casts to pcretest.c to avoid compiler warnings.
432    
433    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
434    
435    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
436        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
437        entirely. This removes changes made in 7 above.
438    
439    17. The CMake files have been updated, and there is now more information about
440        building with CMake in the NON-UNIX-USE document.
441    
442    
443    Version 7.3 28-Aug-07
444    ---------------------
445    
446     1. In the rejigging of the build system that eventually resulted in 7.1, the
447        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
448        brackets there is not right, since it causes compilers to look for an
449        installed pcre.h, not the version that is in the source that is being
450        compiled (which of course may be different). I have changed it back to:
451    
452          #include "pcre.h"
453    
454        I have a vague recollection that the change was concerned with compiling in
455        different directories, but in the new build system, that is taken care of
456        by the VPATH setting the Makefile.
457    
458     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
459        when the subject happened to end in the byte 0x85 (e.g. if the last
460        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
461        characters but of course it shouldn't be taken as a newline when it is part
462        of another character. The bug was that, for an unlimited repeat of . in
463        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
464        characters when looking for a newline.
465    
466     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
467    
468     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
469        in debug output.
470    
471     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
472        long printing in the pcrecpp unittest when running under MinGW.
473    
474     6. ESC_K was left out of the EBCDIC table.
475    
476     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
477        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
478        limit also applies to "virtual nesting" when a pattern is recursive, and in
479        this case 1000 isn't so big. I have been able to remove this limit at the
480        expense of backing off one optimization in certain circumstances. Normally,
481        when pcre_exec() would call its internal match() function recursively and
482        immediately return the result unconditionally, it uses a "tail recursion"
483        feature to save stack. However, when a subpattern that can match an empty
484        string has an unlimited repetition quantifier, it no longer makes this
485        optimization. That gives it a stack frame in which to save the data for
486        checking that an empty string has been matched. Previously this was taken
487        from the 1000-entry workspace that had been reserved. So now there is no
488        explicit limit, but more stack is used.
489    
490     8. Applied Daniel's patches to solve problems with the import/export magic
491        syntax that is required for Windows, and which was going wrong for the
492        pcreposix and pcrecpp parts of the library. These were overlooked when this
493        problem was solved for the main library.
494    
495     9. There were some crude static tests to avoid integer overflow when computing
496        the size of patterns that contain repeated groups with explicit upper
497        limits. As the maximum quantifier is 65535, the maximum group length was
498        set at 30,000 so that the product of these two numbers did not overflow a
499        32-bit integer. However, it turns out that people want to use groups that
500        are longer than 30,000 bytes (though not repeat them that many times).
501        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
502        made it possible to implement the integer overflow checks in a much more
503        dynamic way, which I have now done. The artificial limitation on group
504        length has been removed - we now have only the limit on the total length of
505        the compiled pattern, which depends on the LINK_SIZE setting.
506    
507    10. Fixed a bug in the documentation for get/copy named substring when
508        duplicate names are permitted. If none of the named substrings are set, the
509        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
510        empty string.
511    
512    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
513        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
514        because the ] is interpreted as the first data character and the
515        terminating ] is not found. PCRE has been made compatible with Perl in this
516        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
517        cause memory overwriting.
518    
519    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
520        string has been matched (to stop an infinite loop). It was not recognizing
521        a conditional subpattern that could match an empty string if that
522        subpattern was within another subpattern. For example, it looped when
523        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
524        condition was not nested. This bug has been fixed.
525    
526    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
527        past the start of the subject in the presence of bytes with the top bit
528        set, for example "\x8aBCD".
529    
530    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
531        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
532    
533    14. Optimized (?!) to (*FAIL).
534    
535    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
536        This restricts code points to be within the range 0 to 0x10FFFF, excluding
537        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
538        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
539        does: it's just the validity check that is more restrictive.
540    
541    16. Inserted checks for integer overflows during escape sequence (backslash)
542        processing, and also fixed erroneous offset values for syntax errors during
543        backslash processing.
544    
545    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
546        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
547    
548    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
549        caused an overrun.
550    
551    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
552        something other than just ASCII characters) inside a group that had an
553        unlimited repeat caused a loop at compile time (while checking to see
554        whether the group could match an empty string).
555    
556    20. Debugging a pattern containing \p or \P could cause a crash. For example,
557        [\P{Any}] did so. (Error in the code for printing property names.)
558    
559    21. An orphan \E inside a character class could cause a crash.
560    
561    22. A repeated capturing bracket such as (A)? could cause a wild memory
562        reference during compilation.
563    
564    23. There are several functions in pcre_compile() that scan along a compiled
565        expression for various reasons (e.g. to see if it's fixed length for look
566        behind). There were bugs in these functions when a repeated \p or \P was
567        present in the pattern. These operators have additional parameters compared
568        with \d, etc, and these were not being taken into account when moving along
569        the compiled data. Specifically:
570    
571        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
572            length.
573    
574        (b) An item such as \pL+ within a repeated group could cause crashes or
575            loops.
576    
577        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
578            "reference to non-existent subpattern" error.
579    
580        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
581    
582    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
583        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
584    
585    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
586    
587    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
588        character were causing crashes (broken optimization).
589    
590    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
591        \p or \P) caused a compile-time loop.
592    
593    28. More problems have arisen in unanchored patterns when CRLF is a valid line
594        break. For example, the unstudied pattern [\r\n]A does not match the string
595        "\r\nA" because change 7.0/46 below moves the current point on by two
596        characters after failing to match at the start. However, the pattern \nA
597        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
598        the same is true. There doesn't seem any very clean way out of this, but
599        what I have chosen to do makes the common cases work: PCRE now takes note
600        of whether there can be an explicit match for \r or \n anywhere in the
601        pattern, and if so, 7.0/46 no longer applies. As part of this change,
602        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
603        pattern has explicit CR or LF references.
604    
605    29. Added (*CR) etc for changing newline setting at start of pattern.
606    
607    
608    Version 7.2 19-Jun-07
609    ---------------------
610    
611     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
612        which is apparently normally available under Windows.
613    
614     2. Re-jig the pcregrep tests with different newline settings in an attempt
615        to make them independent of the local environment's newline setting.
616    
617     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
618    
619     4. Some of the "internals" tests were previously cut out when the link size
620        was not 2, because the output contained actual offsets. The recent new
621        "Z" feature of pcretest means that these can be cut out, making the tests
622        usable with all link sizes.
623    
624     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
625        stack recursion. This gives a massive performance boost under BSD, but just
626        a small improvement under Linux. However, it saves one field in the frame
627        in all cases.
628    
629     6. Added more features from the forthcoming Perl 5.10:
630    
631        (a) (?-n) (where n is a string of digits) is a relative subroutine or
632            recursion call. It refers to the nth most recently opened parentheses.
633    
634        (b) (?+n) is also a relative subroutine call; it refers to the nth next
635            to be opened parentheses.
636    
637        (c) Conditions that refer to capturing parentheses can be specified
638            relatively, for example, (?(-2)... or (?(+3)...
639    
640        (d) \K resets the start of the current match so that everything before
641            is not part of it.
642    
643        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
644    
645        (f) \g{name} is another synonym - part of Perl 5.10's unification of
646            reference syntax.
647    
648        (g) (?| introduces a group in which the numbering of parentheses in each
649            alternative starts with the same number.
650    
651        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
652    
653     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
654        PCRE_INFO_JCHANGED.
655    
656     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
657        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
658        for detecting groups that can match an empty string.
659    
660     9. A pattern with a very large number of alternatives (more than several
661        hundred) was running out of internal workspace during the pre-compile
662        phase, where pcre_compile() figures out how much memory will be needed. A
663        bit of new cunning has reduced the workspace needed for groups with
664        alternatives. The 1000-alternative test pattern now uses 12 bytes of
665        workspace instead of running out of the 4096 that are available.
666    
667    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
668    
669    11. Applied patch from Google to remove an optimization that didn't quite work.
670        The report of the bug said:
671    
672          pcrecpp::RE("a*").FullMatch("aaa") matches, while
673          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
674          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
675    
676    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
677        it matched the wrong number of bytes.
678    
679    
680    Version 7.1 24-Apr-07
681    ---------------------
682    
683     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
684        that is more "standard", making use of automake and other Autotools. There
685        is some re-arrangement of the files and adjustment of comments consequent
686        on this.
687    
688     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
689        for recursive directory scanning broke on some systems because the files
690        are not scanned in any specific order and on different systems the order
691        was different. A call to "sort" has been inserted into RunGrepTest for the
692        approprate test as a short-term fix. In the longer term there may be an
693        alternative.
694    
695     3. I had an email from Eric Raymond about problems translating some of PCRE's
696        man pages to HTML (despite the fact that I distribute HTML pages, some
697        people do their own conversions for various reasons). The problems
698        concerned the use of low-level troff macros .br and .in. I have therefore
699        removed all such uses from the man pages (some were redundant, some could
700        be replaced by .nf/.fi pairs). The 132html script that I use to generate
701        HTML has been updated to handle .nf/.fi and to complain if it encounters
702        .br or .in.
703    
704     4. Updated comments in configure.ac that get placed in config.h.in and also
705        arranged for config.h to be included in the distribution, with the name
706        config.h.generic, for the benefit of those who have to compile without
707        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
708    
709     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
710        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
711        makevp.bat for the current PCRE, using the additional files
712        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
713    
714     6. A Windows user reported a minor discrepancy with test 2, which turned out
715        to be caused by a trailing space on an input line that had got lost in his
716        copy. The trailing space was an accident, so I've just removed it.
717    
718     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
719        that is needed.
720    
721     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
722        as "const" (a) because they are and (b) because it helps the PHP
723        maintainers who have recently made a script to detect big data structures
724        in the php code that should be moved to the .rodata section. I remembered
725        to update Builducptable as well, so it won't revert if ucptable.h is ever
726        re-created.
727    
728     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
729        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
730        order to be able to cut out the UTF-8 tables in the latter when UTF-8
731        support is not required. This saves 1.5-2K of code, which is important in
732        some applications.
733    
734        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
735        so as not to refer to the tables, even though these functions will never be
736        called when UTF-8 support is disabled. Otherwise there are problems with a
737        shared library.
738    
739    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
740    
741        (a) It was defining its arguments as char * instead of void *.
742    
743        (b) It was assuming that all moves were upwards in memory; this was true
744            a long time ago when I wrote it, but is no longer the case.
745    
746        The emulated memove() is provided for those environments that have neither
747        memmove() nor bcopy(). I didn't think anyone used it these days, but that
748        is clearly not the case, as these two bugs were recently reported.
749    
750    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
751        and Detrail to create the HTML documentation, the .txt form of the man
752        pages, and it removes trailing spaces from listed files. It also creates
753        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
754        case, it wraps all the #defines with #ifndefs. This script should be run
755        before "make dist".
756    
757    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
758        with Unicode property support.
759    
760        (a) For a maximizing quantifier, if the two different cases of the
761            character were of different lengths in their UTF-8 codings (there are
762            some cases like this - I found 11), and the matching function had to
763            back up over a mixture of the two cases, it incorrectly assumed they
764            were both the same length.
765    
766        (b) When PCRE was configured to use the heap rather than the stack for
767            recursion during matching, it was not correctly preserving the data for
768            the other case of a UTF-8 character when checking ahead for a match
769            while processing a minimizing repeat. If the check also involved
770            matching a wide character, but failed, corruption could cause an
771            erroneous result when trying to check for a repeat of the original
772            character.
773    
774    13. Some tidying changes to the testing mechanism:
775    
776        (a) The RunTest script now detects the internal link size and whether there
777            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
778            values substituted by "configure". (The RunGrepTest script already did
779            this for UTF-8.) The configure.ac script no longer substitutes the
780            relevant variables.
781    
782        (b) The debugging options /B and /D in pcretest show the compiled bytecode
783            with length and offset values. This means that the output is different
784            for different internal link sizes. Test 2 is skipped for link sizes
785            other than 2 because of this, bypassing the problem. Unfortunately,
786            there was also a test in test 3 (the locale tests) that used /B and
787            failed for link sizes other than 2. Rather than cut the whole test out,
788            I have added a new /Z option to pcretest that replaces the length and
789            offset values with spaces. This is now used to make test 3 independent
790            of link size. (Test 2 will be tidied up later.)
791    
792    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
793        segmentation fault instead of returning the appropriate error message.
794    
795    15. In multiline mode when the newline sequence was set to "any", the pattern
796        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
797        This doesn't seem right; it now treats the CRLF combination as the line
798        ending, and so does not match in that case. It's only a pattern such as ^$
799        that would hit this one: something like ^ABC$ would have failed after \r
800        and then tried again after \r\n.
801    
802    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
803        in an attempt to make files that differ only in their line terminators
804        compare equal. This works on Linux.
805    
806    17. Under certain error circumstances pcregrep might try to free random memory
807        as it exited. This is now fixed, thanks to valgrind.
808    
809    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
810        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
811        was because its rules for how to advance for /g after matching an empty
812        string at the end of a line did not allow for this case. They now check for
813        it specially.
814    
815    20. pcretest is supposed to handle patterns and data of any length, by
816        extending its buffers when necessary. It was getting this wrong when the
817        buffer for a data line had to be extended.
818    
819    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
820        CRLF as a newline sequence.
821    
822    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
823        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
824        I have nevertheless tidied it up.
825    
826    23. Added some casts to kill warnings from HP-UX ia64 compiler.
827    
828    24. Added a man page for pcre-config.
829    
830    
831    Version 7.0 19-Dec-06
832    ---------------------
833    
834     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
835        moving to gcc 4.1.1.
836    
837     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
838        sys/time.h, which is documented as needed for this function. It doesn't
839        seem to matter on Linux, but it showed up on some releases of OS X.
840    
841     3. It seems that there are systems where bytes whose values are greater than
842        127 match isprint() in the "C" locale. The "C" locale should be the
843        default when a C program starts up. In most systems, only ASCII printing
844        characters match isprint(). This difference caused the output from pcretest
845        to vary, making some of the tests fail. I have changed pcretest so that:
846    
847        (a) When it is outputting text in the compiled version of a pattern, bytes
848            other than 32-126 are always shown as hex escapes.
849    
850        (b) When it is outputting text that is a matched part of a subject string,
851            it does the same, unless a different locale has been set for the match
852            (using the /L modifier). In this case, it uses isprint() to decide.
853    
854     4. Fixed a major bug that caused incorrect computation of the amount of memory
855        required for a compiled pattern when options that changed within the
856        pattern affected the logic of the preliminary scan that determines the
857        length. The relevant options are -x, and -i in UTF-8 mode. The result was
858        that the computed length was too small. The symptoms of this bug were
859        either the PCRE error "internal error: code overflow" from pcre_compile(),
860        or a glibc crash with a message such as "pcretest: free(): invalid next
861        size (fast)". Examples of patterns that provoked this bug (shown in
862        pcretest format) are:
863    
864          /(?-x: )/x
865          /(?x)(?-x: \s*#\s*)/
866          /((?i)[\x{c0}])/8
867          /(?i:[\x{c0}])/8
868    
869        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
870        is now done differently.
871    
872     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
873        wrapper classes; (b) implement a new function in the C++ scanner that is
874        more efficient than the old way of doing things because it avoids levels of
875        recursion in the regex matching; (c) add a paragraph to the documentation
876        for the FullMatch() function.
877    
878     6. The escape sequence \n was being treated as whatever was defined as
879        "newline". Not only was this contrary to the documentation, which states
880        that \n is character 10 (hex 0A), but it also went horribly wrong when
881        "newline" was defined as CRLF. This has been fixed.
882    
883     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
884        was being set to -1 for the "end of line" case (supposedly a value that no
885        character can have). Though this value is never used (the check for end of
886        line is "zero bytes in current character"), it caused compiler complaints.
887        I've changed it to 0xffffffff.
888    
889     8. In pcre_version.c, the version string was being built by a sequence of
890        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
891        string (as it is for production releases) called a macro with an empty
892        argument. The C standard says the result of this is undefined. The gcc
893        compiler treats it as an empty string (which was what was wanted) but it is
894        reported that Visual C gives an error. The source has been hacked around to
895        avoid this problem.
896    
897     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
898        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
899        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
900        of them did).
901    
902    10. Originally, pcretest opened its input and output without "b"; then I was
903        told that "b" was needed in some environments, so it was added for release
904        5.0 to both the input and output. (It makes no difference on Unix-like
905        systems.) Later I was told that it is wrong for the input on Windows. I've
906        now abstracted the modes into two macros, to make it easier to fiddle with
907        them, and removed "b" from the input mode under Windows.
908    
909    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
910    
911    12. Added -help and --help to pcretest as an official way of being reminded
912        of the options.
913    
914    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
915        and pcrecpp.cc because they annoy compilers at high warning levels.
916    
917    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
918    
919    15. Fixed an occurrence of == in configure.ac that should have been = (shell
920        scripts are not C programs :-) and which was not noticed because it works
921        on Linux.
922    
923    16. pcretest is supposed to handle any length of pattern and data line (as one
924        line or as a continued sequence of lines) by extending its input buffer if
925        necessary. This feature was broken for very long pattern lines, leading to
926        a string of junk being passed to pcre_compile() if the pattern was longer
927        than about 50K.
928    
929    17. I have done a major re-factoring of the way pcre_compile() computes the
930        amount of memory needed for a compiled pattern. Previously, there was code
931        that made a preliminary scan of the pattern in order to do this. That was
932        OK when PCRE was new, but as the facilities have expanded, it has become
933        harder and harder to keep it in step with the real compile phase, and there
934        have been a number of bugs (see for example, 4 above). I have now found a
935        cunning way of running the real compile function in a "fake" mode that
936        enables it to compute how much memory it would need, while actually only
937        ever using a few hundred bytes of working memory and without too many
938        tests of the mode. This should make future maintenance and development
939        easier. A side effect of this work is that the limit of 200 on the nesting
940        depth of parentheses has been removed (though this was never a serious
941        limitation, I suspect). However, there is a downside: pcre_compile() now
942        runs more slowly than before (30% or more, depending on the pattern). I
943        hope this isn't a big issue. There is no effect on runtime performance.
944    
945    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
946        newline (only possible for the last line of a file) and it was a
947        pattern that set a locale (followed by /Lsomething), pcretest crashed.
948    
949    19. Added additional timing features to pcretest. (1) The -tm option now times
950        matching only, not compiling. (2) Both -t and -tm can be followed, as a
951        separate command line item, by a number that specifies the number of
952        repeats to use when timing. The default is 50000; this gives better
953        precision, but takes uncomfortably long for very large patterns.
954    
955    20. Extended pcre_study() to be more clever in cases where a branch of a
956        subpattern has no definite first character. For example, (a*|b*)[cd] would
957        previously give no result from pcre_study(). Now it recognizes that the
958        first character must be a, b, c, or d.
959    
960    21. There was an incorrect error "recursive call could loop indefinitely" if
961        a subpattern (or the entire pattern) that was being tested for matching an
962        empty string contained only one non-empty item after a nested subpattern.
963        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
964        incorrectly, because the \d was being skipped in the check.
965    
966    22. The pcretest program now has a new pattern option /B and a command line
967        option -b, which is equivalent to adding /B to every pattern. This causes
968        it to show the compiled bytecode, without the additional information that
969        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
970        is the same as /B/I).
971    
972    23. A new optimization is now able automatically to treat some sequences such
973        as a*b as a*+b. More specifically, if something simple (such as a character
974        or a simple class like \d) has an unlimited quantifier, and is followed by
975        something that cannot possibly match the quantified thing, the quantifier
976        is automatically "possessified".
977    
978    24. A recursive reference to a subpattern whose number was greater than 39
979        went wrong under certain circumstances in UTF-8 mode. This bug could also
980        have affected the operation of pcre_study().
981    
982    25. Realized that a little bit of performance could be had by replacing
983        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
984    
985    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
986    
987    27. Possessive quantifiers such as a++ were previously implemented by turning
988        them into atomic groups such as ($>a+). Now they have their own opcodes,
989        which improves performance. This includes the automatically created ones
990        from 23 above.
991    
992    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
993        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
994        the first matched character to be a colon. This applied both to named and
995        numbered groups.
996    
997    29. The ucpinternal.h header file was missing its idempotency #ifdef.
998    
999    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1000        building PCRE on Windows easier, so I have included it in the distribution.
1001    
1002    31. There is now a check in pcretest against a ridiculously large number being
1003        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1004        loop, the loop is abandoned.
1005    
1006    32. Forward references to subpatterns in conditions such as (?(2)...) where
1007        subpattern 2 is defined later cause pcre_compile() to search forwards in
1008        the pattern for the relevant set of parentheses. This search went wrong
1009        when there were unescaped parentheses in a character class, parentheses
1010        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1011    
1012    33. "Subroutine" calls and backreferences were previously restricted to
1013        referencing subpatterns earlier in the regex. This restriction has now
1014        been removed.
1015    
1016    34. Added a number of extra features that are going to be in Perl 5.10. On the
1017        whole, these are just syntactic alternatives for features that PCRE had
1018        previously implemented using the Python syntax or my own invention. The
1019        other formats are all retained for compatibility.
1020    
1021        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1022            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1023            also .NET compatible.
1024    
1025        (b) A recursion or subroutine call to a named group can now be defined as
1026            (?&name) as well as (?P>name).
1027    
1028        (c) A backreference to a named group can now be defined as \k<name> or
1029            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1030            5.10, are also .NET compatible.
1031    
1032        (d) A conditional reference to a named group can now use the syntax
1033            (?(<name>) or (?('name') as well as (?(name).
1034    
1035        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1036            groups (named and numbered) that are never evaluated inline, but can be
1037            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1038            is always false. There may be only one alternative in such a group.
1039    
1040        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1041            as the simple (?(R). The condition is true only if the most recent
1042            recursion is that of the given number or name. It does not search out
1043            through the entire recursion stack.
1044    
1045        (g) The escape \gN or \g{N} has been added, where N is a positive or
1046            negative number, specifying an absolute or relative reference.
1047    
1048    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1049        some "unreachable code" warnings.
1050    
1051    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1052        things, this adds five new scripts.
1053    
1054    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1055        There were also incompatibilities regarding the handling of \Q..\E inside
1056        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1057        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1058    
1059    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1060        matches an empty string, and forcibly breaks the loop. There were bugs in
1061        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1062        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1063        separate and independent bugs (that affected different cases) have been
1064        fixed.
1065    
1066    39. Refactored the code to abolish the use of different opcodes for small
1067        capturing bracket numbers. This is a tidy that I avoided doing when I
1068        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1069        The new approach is not only tidier, it makes it possible to reduce the
1070        memory needed to fix the previous bug (38).
1071    
1072    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1073        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1074        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1075        mode.
1076    
1077    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1078        report.
1079    
1080    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1081        copy construction and assignment in the C++ wrapper.
1082    
1083    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1084        couple of bugs that could have given wrong results in the "--newline=crlf"
1085        case.
1086    
1087    44. Added a number of casts and did some reorganization of signed/unsigned int
1088        variables following suggestions from Dair Grant. Also renamed the variable
1089        "this" as "item" because it is a C++ keyword.
1090    
1091    45. Arranged for dftables to add
1092    
1093          #include "pcre_internal.h"
1094    
1095        to pcre_chartables.c because without it, gcc 4.x may remove the array
1096        definition from the final binary if PCRE is built into a static library and
1097        dead code stripping is activated.
1098    
1099    46. For an unanchored pattern, if a match attempt fails at the start of a
1100        newline sequence, and the newline setting is CRLF or ANY, and the next two
1101        characters are CRLF, advance by two characters instead of one.
1102    
1103    
1104    Version 6.7 04-Jul-06
1105    ---------------------
1106    
1107     1. In order to handle tests when input lines are enormously long, pcretest has
1108        been re-factored so that it automatically extends its buffers when
1109        necessary. The code is crude, but this _is_ just a test program. The
1110        default size has been increased from 32K to 50K.
1111    
1112     2. The code in pcre_study() was using the value of the re argument before
1113        testing it for NULL. (Of course, in any sensible call of the function, it
1114        won't be NULL.)
1115    
1116     3. The memmove() emulation function in pcre_internal.h, which is used on
1117        systems that lack both memmove() and bcopy() - that is, hardly ever -
1118        was missing a "static" storage class specifier.
1119    
1120     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1121        containing an extended class (one that cannot be represented by a bitmap
1122        because it contains high-valued characters or Unicode property items, e.g.
1123        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1124        pattern, but PCRE should not loop if you do not (it no longer does).
1125        [Detail: two cases were found: (a) a repeated subpattern containing an
1126        extended class; (b) a recursive reference to a subpattern that followed a
1127        previous extended class. It wasn't skipping over the extended class
1128        correctly when UTF-8 mode was not set.]
1129    
1130     5. A negated single-character class was not being recognized as fixed-length
1131        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1132        compile error "lookbehind assertion is not fixed length".
1133    
1134     6. The RunPerlTest auxiliary script was showing an unexpected difference
1135        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1136        write a Perl script that can interpret lines of an input file either as
1137        byte characters or as UTF-8, which is what "perltest" was being required to
1138        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1139        can't do is switch easily at run time between having the "use utf8;" pragma
1140        or not. In the end, I fudged it by using the RunPerlTest script to insert
1141        "use utf8;" explicitly for the UTF-8 tests.
1142    
1143     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1144        the end of the subject string, contrary to the documentation and to what
1145        Perl does. This was true of both matching functions. Now it matches only at
1146        the start of the subject and immediately after *internal* newlines.
1147    
1148     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1149        a pointer to an int instead of a pointer to an unsigned long int. This
1150        caused problems on 64-bit systems.
1151    
1152     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1153        instance of the 'standard' template library not being so standard".
1154    
1155    10. There was no check on the number of named subpatterns nor the maximum
1156        length of a subpattern name. The product of these values is used to compute
1157        the size of the memory block for a compiled pattern. By supplying a very
1158        long subpattern name and a large number of named subpatterns, the size
1159        computation could be caused to overflow. This is now prevented by limiting
1160        the length of names to 32 characters, and the number of named subpatterns
1161        to 10,000.
1162    
1163    11. Subpatterns that are repeated with specific counts have to be replicated in
1164        the compiled pattern. The size of memory for this was computed from the
1165        length of the subpattern and the repeat count. The latter is limited to
1166        65535, but there was no limit on the former, meaning that integer overflow
1167        could in principle occur. The compiled length of a repeated subpattern is
1168        now limited to 30,000 bytes in order to prevent this.
1169    
1170    12. Added the optional facility to have named substrings with the same name.
1171    
1172    13. Added the ability to use a named substring as a condition, using the
1173        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1174        are numbers (not recommended). Forward references are permitted.
1175    
1176    14. Added forward references in named backreferences (if you see what I mean).
1177    
1178    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1179        pattern could run off the end of the subject. For example, the pattern
1180        "(?s)(.{1,5})"8 did this with the subject "ab".
1181    
1182    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1183        PCRE_CASELESS was set when matching characters that were quantified with ?
1184        or *.
1185    
1186    17. A character class other than a single negated character that had a minimum
1187        but no maximum quantifier - for example [ab]{6,} - was not handled
1188        correctly by pce_dfa_exec(). It would match only one character.
1189    
1190    18. A valid (though odd) pattern that looked like a POSIX character
1191        class but used an invalid character after [ (for example [[,abc,]]) caused
1192        pcre_compile() to give the error "Failed: internal error: code overflow" or
1193        in some cases to crash with a glibc free() error. This could even happen if
1194        the pattern terminated after [[ but there just happened to be a sequence of
1195        letters, a binary zero, and a closing ] in the memory that followed.
1196    
1197    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1198        over the years. Originally (before any Unicode support), just the bottom 8
1199        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1200        output from "man perlunicode" includes this:
1201    
1202          The regular expression compiler produces polymorphic opcodes.  That
1203          is, the pattern adapts to the data and automatically switches to
1204          the Unicode character scheme when presented with Unicode data--or
1205          instead uses a traditional byte scheme when presented with byte
1206          data.
1207    
1208        Sadly, a wide octal escape does not cause a switch, and in a string with
1209        no other multibyte characters, these octal escapes are treated as before.
1210        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1211        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1212        Unicode string.
1213    
1214        I have not perpetrated such confusion in PCRE. Up till now, it took just
1215        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1216        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1217        translate to the appropriate multibyte character.
1218    
1219    29. Applied some refactoring to reduce the number of warnings from Microsoft
1220        and Borland compilers. This has included removing the fudge introduced
1221        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1222        a warning about an unused variable.
1223    
1224    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1225        characters since release 4.0, because Perl (from release 5.004) does not.
1226        [Or at least, is documented not to: some releases seem to be in conflict
1227        with the documentation.] However, when a pattern was studied with
1228        pcre_study() and all its branches started with \s, PCRE still included VT
1229        as a possible starting character. Of course, this did no harm; it just
1230        caused an unnecessary match attempt.
1231    
1232    22. Removed a now-redundant internal flag bit that recorded the fact that case
1233        dependency changed within the pattern. This was once needed for "required
1234        byte" processing, but is no longer used. This recovers a now-scarce options
1235        bit. Also moved the least significant internal flag bit to the most-
1236        significant bit of the word, which was not previously used (hangover from
1237        the days when it was an int rather than a uint) to free up another bit for
1238        the future.
1239    
1240    23. Added support for CRLF line endings as well as CR and LF. As well as the
1241        default being selectable at build time, it can now be changed at runtime
1242        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1243        specify that it is scanning data with non-default line endings.
1244    
1245    24. Changed the definition of CXXLINK to make it agree with the definition of
1246        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1247    
1248    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1249        recursions. This makes a big different to stack usage for some patterns.
1250    
1251    26. If a subpattern containing a named recursion or subroutine reference such
1252        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1253        the space required for the compiled pattern went wrong and gave too small a
1254        value. Depending on the environment, this could lead to "Failed: internal
1255        error: code overflow at offset 49" or "glibc detected double free or
1256        corruption" errors.
1257    
1258    27. Applied patches from Google (a) to support the new newline modes and (b) to
1259        advance over multibyte UTF-8 characters in GlobalReplace.
1260    
1261    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1262        difference for some implementation of PCRE in some Windows version.
1263    
1264    29. Added some extra testing facilities to pcretest:
1265    
1266        \q<number>   in a data line sets the "match limit" value
1267        \Q<number>   in a data line sets the "match recursion limt" value
1268        -S <number>  sets the stack size, where <number> is in megabytes
1269    
1270        The -S option isn't available for Windows.
1271    
1272    
1273    Version 6.6 06-Feb-06
1274    ---------------------
1275    
1276     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1277        in pcreposix.h. I have copied the definition from pcre.h.
1278    
1279     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1280        because pcre.h is no longer a built file.
1281    
1282     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1283        not normally included in the compiled code.
1284    
1285    
1286    Version 6.5 01-Feb-06
1287    ---------------------
1288    
1289     1. When using the partial match feature with pcre_dfa_exec(), it was not
1290        anchoring the second and subsequent partial matches at the new starting
1291        point. This could lead to incorrect results. For example, with the pattern
1292        /1234/, partially matching against "123" and then "a4" gave a match.
1293    
1294     2. Changes to pcregrep:
1295    
1296        (a) All non-match returns from pcre_exec() were being treated as failures
1297            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1298            error message is output. Some extra information is given for the
1299            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1300            probably the only errors that are likely to be caused by users (by
1301            specifying a regex that has nested indefinite repeats, for instance).
1302            If there are more than 20 of these errors, pcregrep is abandoned.
1303    
1304        (b) A binary zero was treated as data while matching, but terminated the
1305            output line if it was written out. This has been fixed: binary zeroes
1306            are now no different to any other data bytes.
1307    
1308        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1309            used to set a locale for matching. The --locale=xxxx long option has
1310            been added (no short equivalent) to specify a locale explicitly on the
1311            pcregrep command, overriding the environment variables.
1312    
1313        (d) When -B was used with -n, some line numbers in the output were one less
1314            than they should have been.
1315    
1316        (e) Added the -o (--only-matching) option.
1317    
1318        (f) If -A or -C was used with -c (count only), some lines of context were
1319            accidentally printed for the final match.
1320    
1321        (g) Added the -H (--with-filename) option.
1322    
1323        (h) The combination of options -rh failed to suppress file names for files
1324            that were found from directory arguments.
1325    
1326        (i) Added the -D (--devices) and -d (--directories) options.
1327    
1328        (j) Added the -F (--fixed-strings) option.
1329    
1330        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1331    
1332        (l) Added the --colo(u)r option.
1333    
1334        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1335            is not present by default.
1336    
1337     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1338        items such as (?R) or (?1), when the recursion could match a number of
1339        alternatives. If it matched one of the alternatives, but subsequently,
1340        outside the recursion, there was a failure, the code tried to back up into
1341        the recursion. However, because of the way PCRE is implemented, this is not
1342        possible, and the result was an incorrect result from the match.
1343    
1344        In order to prevent this happening, the specification of recursion has
1345        been changed so that all such subpatterns are automatically treated as
1346        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1347    
1348     4. I had overlooked the fact that, in some locales, there are characters for
1349        which isalpha() is true but neither isupper() nor islower() are true. In
1350        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1351        and ordfeminine) are like this. This affected the treatment of \w and \W
1352        when they appeared in character classes, but not when they appeared outside
1353        a character class. The bit map for "word" characters is now created
1354        separately from the results of isalnum() instead of just taking it from the
1355        upper, lower, and digit maps. (Plus the underscore character, of course.)
1356    
1357     5. The above bug also affected the handling of POSIX character classes such as
1358        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1359        permanent tables. Instead, the bit maps for such a class were previously
1360        created as the appropriate unions of the upper, lower, and digit bitmaps.
1361        Now they are created by subtraction from the [[:word:]] class, which has
1362        its own bitmap.
1363    
1364     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1365        It is created by subtracting the vertical space characters (\x09, \x0a,
1366        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1367        subtraction was done in the overall bitmap for a character class, meaning
1368        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1369        be recognized. This bug has been fixed.
1370    
1371     7. Patches from the folks at Google:
1372    
1373          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1374          real life, but is still worth protecting against".
1375    
1376          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1377          regular expressions".
1378    
1379          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1380          have it.
1381    
1382          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1383          "configure" and the latter not, in order to fix a problem somebody had
1384          with compiling the Arg class on HP-UX.
1385    
1386          (e) Improve the error-handling of the C++ wrapper a little bit.
1387    
1388          (f) New tests for checking recursion limiting.
1389    
1390     8. The pcre_memmove() function, which is used only if the environment does not
1391        have a standard memmove() function (and is therefore rarely compiled),
1392        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1393        returning a result (though PCRE never actually uses the result).
1394    
1395     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1396        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1397        returned instead of calling malloc() with an overflowing number that would
1398        most likely cause subsequent chaos.
1399    
1400    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1401    
1402    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1403        with this option is matched, the nmatch and pmatch options of regexec() are
1404        ignored.
1405    
1406    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1407        provided in case anyone wants to the the POSIX interface with UTF-8
1408        strings.
1409    
1410    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1411        C++ linking (needed for some HP-UX environments).
1412    
1413    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1414        (unused parameter) and in the pcre_printint() function (omitted "default"
1415        switch label when the default is to do nothing).
1416    
1417    15. Added some code to make it possible, when PCRE is compiled as a C++
1418        library, to replace subject pointers for pcre_exec() with a smart pointer
1419        class, thus making it possible to process discontinuous strings.
1420    
1421    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1422        much the same function. They were added by different people who were trying
1423        to make PCRE easy to compile on non-Unix systems. It has been suggested
1424        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1425        for compiling on Windows systems. I have therefore replaced it with
1426        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1427        defaults to "extern" for C or "extern C" for C++, which works fine on
1428        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1429        SCOPE with something explicit in config.h. In addition:
1430    
1431        (a) pcreposix.h still had just "extern" instead of either of these macros;
1432            I have replaced it with PCRE_DATA_SCOPE.
1433    
1434        (b) Functions such as _pcre_xclass(), which are internal to the library,
1435            but external in the C sense, all had PCRE_EXPORT in their definitions.
1436            This is apparently wrong for the Windows case, so I have removed it.
1437            (It makes no difference on Unix-like systems.)
1438    
1439    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1440        of recursive calls to match(). This is different to MATCH_LIMIT because
1441        that limits the total number of calls to match(), not all of which increase
1442        the depth of recursion. Limiting the recursion depth limits the amount of
1443        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1444        when PCRE is compiled, and changed at run time. A patch from Google adds
1445        this functionality to the C++ interface.
1446    
1447    18. Changes to the handling of Unicode character properties:
1448    
1449        (a) Updated the table to Unicode 4.1.0.
1450    
1451        (b) Recognize characters that are not in the table as "Cn" (undefined).
1452    
1453        (c) I revised the way the table is implemented to a much improved format
1454            which includes recognition of ranges. It now supports the ranges that
1455            are defined in UnicodeData.txt, and it also amalgamates other
1456            characters into ranges. This has reduced the number of entries in the
1457            table from around 16,000 to around 3,000, thus reducing its size
1458            considerably. I realized I did not need to use a tree structure after
1459            all - a binary chop search is just as efficient. Having reduced the
1460            number of entries, I extended their size from 6 bytes to 8 bytes to
1461            allow for more data.
1462    
1463        (d) Added support for Unicode script names via properties such as \p{Han}.
1464    
1465    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1466        matching that character.
1467    
1468    20. When matching a repeated Unicode property with a minimum greater than zero,
1469        (for example \pL{2,}), PCRE could look past the end of the subject if it
1470        reached it while seeking the minimum number of characters. This could
1471        happen only if some of the characters were more than one byte long, because
1472        there is a check for at least the minimum number of bytes.
1473    
1474    21. Refactored the implementation of \p and \P so as to be more general, to
1475        allow for more different types of property in future. This has changed the
1476        compiled form incompatibly. Anybody with saved compiled patterns that use
1477        \p or \P will have to recompile them.
1478    
1479    22. Added "Any" and "L&" to the supported property types.
1480    
1481    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1482        but give a compile time error if the value is greater than 0xff.
1483    
1484    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1485        accidentally not being installed or uninstalled.
1486    
1487    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1488        made were to insert the current release number. This seemed silly, because
1489        it made things harder for people building PCRE on systems that don't run
1490        "configure". I have turned pcre.h into a distributed file, no longer built
1491        by "configure", with the version identification directly included. There is
1492        no longer a pcre.h.in file.
1493    
1494        However, this change necessitated a change to the pcre-config script as
1495        well. It is built from pcre-config.in, and one of the substitutions was the
1496        release number. I have updated configure.ac so that ./configure now finds
1497        the release number by grepping pcre.h.
1498    
1499    26. Added the ability to run the tests under valgrind.
1500    
1501    
1502    Version 6.4 05-Sep-05
1503    ---------------------
1504    
1505     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1506        "--" to be printed when multiple files were scanned, even when none of the
1507        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1508        consider it to be a bug, and have restored the previous behaviour.
1509    
1510     2. A couple of code tidies to get rid of compiler warnings.
1511    
1512     3. The pcretest program used to cheat by referring to symbols in the library
1513        whose names begin with _pcre_. These are internal symbols that are not
1514        really supposed to be visible externally, and in some environments it is
1515        possible to suppress them. The cheating is now confined to including
1516        certain files from the library's source, which is a bit cleaner.
1517    
1518     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1519        file's purpose clearer.
1520    
1521     5. Reorganized pcre_ucp_findchar().
1522    
1523    
1524    Version 6.3 15-Aug-05
1525    ---------------------
1526    
1527     1. The file libpcre.pc.in did not have general read permission in the tarball.
1528    
1529     2. There were some problems when building without C++ support:
1530    
1531        (a) If C++ support was not built, "make install" and "make test" still
1532            tried to test it.
1533    
1534        (b) There were problems when the value of CXX was explicitly set. Some
1535            changes have been made to try to fix these, and ...
1536    
1537        (c) --disable-cpp can now be used to explicitly disable C++ support.
1538    
1539        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1540            backslash in a target when C++ was disabled. This confuses some
1541            versions of "make", apparently. Using an intermediate variable solves
1542            this. (Same for CPP_LOBJ.)
1543    
1544     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1545        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1546        necessary on certain architectures.
1547    
1548     4. Added a setting of -export-symbols-regex to the link command to remove
1549        those symbols that are exported in the C sense, but actually are local
1550        within the library, and not documented. Their names all begin with
1551        "_pcre_". This is not a perfect job, because (a) we have to except some
1552        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1553        available (and never for static libraries). I have made a note to try to
1554        find a way round (a) in the future.
1555    
1556    
1557    Version 6.2 01-Aug-05
1558    ---------------------
1559    
1560     1. There was no test for integer overflow of quantifier values. A construction
1561        such as {1111111111111111} would give undefined results. What is worse, if
1562        a minimum quantifier for a parenthesized subpattern overflowed and became
1563        negative, the calculation of the memory size went wrong. This could have
1564        led to memory overwriting.
1565    
1566     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1567    
1568     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1569        operating environments where this matters.
1570    
1571     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1572        PCRE options from within the C++ wrapper.
1573    
1574     5. Named capturing subpatterns were not being correctly counted when a pattern
1575        was compiled. This caused two problems: (a) If there were more than 100
1576        such subpatterns, the calculation of the memory needed for the whole
1577        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1578        back references of the form \12, where the number was greater than 9, were
1579        not recognized as back references, even though there were sufficient
1580        previous subpatterns.
1581    
1582     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1583        versions of gcc, e.g. 2.95.4.
1584    
1585    
1586    Version 6.1 21-Jun-05
1587    ---------------------
1588    
1589     1. There was one reference to the variable "posix" in pcretest.c that was not
1590        surrounded by "#if !defined NOPOSIX".
1591    
1592     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1593        the cross-check on the old pcre_info() function, for the benefit of the
1594        cut-down version of PCRE that is currently imported into Exim.
1595    
1596     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1597        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1598        patterns that start (?i) but I don't think that matters. The use of (?i) is
1599        just an example; this all applies to the other options as well.
1600    
1601     4. Since libtool seems to echo the compile commands it is issuing, the output
1602        from "make" can be reduced a bit by putting "@" in front of each libtool
1603        compile command.
1604    
1605     5. Patch from the folks at Google for configure.in to be a bit more thorough
1606        in checking for a suitable C++ installation before trying to compile the
1607        C++ stuff. This should fix a reported problem when a compiler was present,
1608        but no suitable headers.
1609    
1610     6. The man pages all had just "PCRE" as their title. I have changed them to
1611        be the relevant file name. I have also arranged that these names are
1612        retained in the file doc/pcre.txt, which is a concatenation in text format
1613        of all the man pages except the little individual ones for each function.
1614    
1615     7. The NON-UNIX-USE file had not been updated for the different set of source
1616        files that come with release 6. I also added a few comments about the C++
1617        wrapper.
1618    
1619    
1620  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
1621  ---------------------  ---------------------
1622    

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