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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 373 by ph10, Fri Sep 5 10:25:46 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    18. Tidied a few places to stop certain compilers from issuing warnings.
75    
76    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
77        supplied by Stefan Weber. I made a further small update for 7.8 because
78        there is a change of source arrangements: the pcre_searchfuncs.c module is
79        replaced by pcre_ucd.c.
80    
81    
82    Version 7.7 07-May-08
83    ---------------------
84    
85    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
86        a string to a long long, pretend we don't even have a long long." This is
87        done by checking for the strtoq, strtoll, and _strtoi64 functions.
88    
89    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
90        pre-7.6 versions, which defined a global no_arg variable instead of putting
91        it in the RE class. (See also #8 below.)
92    
93    3.  Remove a line of dead code, identified by coverity and reported by Nuno
94        Lopes.
95    
96    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
97    
98        (1) The include/exclude patterns were being applied to the whole pathnames
99            of files, instead of just to the final components.
100    
101        (2) If there was more than one level of directory, the subdirectories were
102            skipped unless they satisfied the include/exclude conditions. This is
103            inconsistent with GNU grep (and could even be seen as contrary to the
104            pcregrep specification - which I improved to make it absolutely clear).
105            The action now is always to scan all levels of directory, and just
106            apply the include/exclude patterns to regular files.
107    
108    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
109        --exclude_dir in the tests to avoid scanning .svn directories.
110    
111    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
112        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
113        doesn't support NULs in patterns.
114    
115    7.  Added some missing "const"s to declarations of static tables in
116        pcre_compile.c and pcre_dfa_exec.c.
117    
118    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
119        caused by fix #2  above. (Subsequently also a second patch to fix the
120        first patch. And a third patch - this was a messy problem.)
121    
122    9.  Applied Craig's patch to remove the use of push_back().
123    
124    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
125        matching function regexec().
126    
127    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
128        which, however, unlike Perl's \g{...}, are subroutine calls, not back
129        references. PCRE supports relative numbers with this syntax (I don't think
130        Oniguruma does).
131    
132    12. Previously, a group with a zero repeat such as (...){0} was completely
133        omitted from the compiled regex. However, this means that if the group
134        was called as a subroutine from elsewhere in the pattern, things went wrong
135        (an internal error was given). Such groups are now left in the compiled
136        pattern, with a new opcode that causes them to be skipped at execution
137        time.
138    
139    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
140        to the way PCRE behaves:
141    
142        (a) A lone ] character is dis-allowed (Perl treats it as data).
143    
144        (b) A back reference to an unmatched subpattern matches an empty string
145            (Perl fails the current match path).
146    
147        (c) A data ] in a character class must be notated as \] because if the
148            first data character in a class is ], it defines an empty class. (In
149            Perl it is not possible to have an empty class.) The empty class []
150            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
151            The negative empty class [^] matches any one character, independently
152            of the DOTALL setting.
153    
154    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
155        non-existent subpattern following a character class starting with ']' and
156        containing () gave an internal compiling error instead of "reference to
157        non-existent subpattern". Fortunately, when the pattern did exist, the
158        compiled code was correct. (When scanning forwards to check for the
159        existencd of the subpattern, it was treating the data ']' as terminating
160        the class, so got the count wrong. When actually compiling, the reference
161        was subsequently set up correctly.)
162    
163    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
164        it was being rejected as not supported by pcre_dfa_exec(), even though
165        other assertions are supported. I have made pcre_dfa_exec() support
166        (*FAIL).
167    
168    16. The implementation of 13c above involved the invention of a new opcode,
169        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
170        cannot be changed at match time, I realized I could make a small
171        improvement to matching performance by compiling OP_ALLANY instead of
172        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
173        on the OP_ANY path.
174    
175    17. Compiling pcretest on Windows with readline support failed without the
176        following two fixes: (1) Make the unistd.h include conditional on
177        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
178    
179    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
180        ncurses library to be included for pcretest when ReadLine support is
181        requested, but also to allow for it to be overridden. This patch came from
182        Daniel Bergström.
183    
184    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
185        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
186        any errors with the current Unicode tables. Thanks to Peter Kankowski for
187        spotting this.
188    
189    
190    Version 7.6 28-Jan-08
191    ---------------------
192    
193    1.  A character class containing a very large number of characters with
194        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
195        overflow.
196    
197    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
198        HAVE_LONG_LONG is not defined.
199    
200    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
201        bring them up to date and include new features. This patch includes:
202    
203        - Fixed PH's badly added libz and libbz2 support.
204        - Fixed a problem with static linking.
205        - Added pcredemo. [But later removed - see 7 below.]
206        - Fixed dftables problem and added an option.
207        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
208            HAVE_LONG_LONG.
209        - Added readline support for pcretest.
210        - Added an listing of the option settings after cmake has run.
211    
212    4.  A user submitted a patch to Makefile that makes it easy to create
213        "pcre.dll" under mingw when using Configure/Make. I added stuff to
214        Makefile.am that cause it to include this special target, without
215        affecting anything else. Note that the same mingw target plus all
216        the other distribution libraries and programs are now supported
217        when configuring with CMake (see 6 below) instead of with
218        Configure/Make.
219    
220    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
221        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
222        exported in the Windows port". It has not yet been confirmed that the patch
223        solves the problem, but it does no harm.
224    
225    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
226        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
227        with CMake, and also correct the comment about stack recursion.
228    
229    7.  Remove the automatic building of pcredemo from the ./configure system and
230        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
231        of a program that users should build themselves after PCRE is installed, so
232        building it automatically is not really right. What is more, it gave
233        trouble in some build environments.
234    
235    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
236    
237    
238    Version 7.5 10-Jan-08
239    ---------------------
240    
241    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
242        values in parens when parsing an RE using the C++ wrapper."
243    
244    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
245        Characters greater than 255 were excluded from the class instead of being
246        included.
247    
248    3.  The same bug as (2) above applied to negated POSIX classes such as
249        [:^space:].
250    
251    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
252        defined or documented. It seems to have been a typo for PCRE_STATIC, so
253        I have changed it.
254    
255    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
256        first named subpattern) and a construct such as (?&a) would reference the
257        first named subpattern whose name started with "a" (in other words, the
258        length check was missing). Both these problems are fixed. "Subpattern name
259        expected" is now given for (?&) (a zero-length name), and this patch also
260        makes it give the same error for \k'' (previously it complained that that
261        was a reference to a non-existent subpattern).
262    
263    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
264        this is right because (?- can be followed by option settings as well as by
265        digits. I have, however, made the messages clearer.
266    
267    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
268        than the number used in the conditional) now cause a compile-time error.
269        This is actually not compatible with Perl, which accepts such patterns, but
270        treats the conditional as always being FALSE (as PCRE used to), but it
271        seems to me that giving a diagnostic is better.
272    
273    8.  Change "alphameric" to the more common word "alphanumeric" in comments
274        and messages.
275    
276    9.  Fix two occurrences of "backslash" in comments that should have been
277        "backspace".
278    
279    10. Remove two redundant lines of code that can never be obeyed (their function
280        was moved elsewhere).
281    
282    11. The program that makes PCRE's Unicode character property table had a bug
283        which caused it to generate incorrect table entries for sequences of
284        characters that have the same character type, but are in different scripts.
285        It amalgamated them into a single range, with the script of the first of
286        them. In other words, some characters were in the wrong script. There were
287        thirteen such cases, affecting characters in the following ranges:
288    
289          U+002b0 - U+002c1
290          U+0060c - U+0060d
291          U+0061e - U+00612
292          U+0064b - U+0065e
293          U+0074d - U+0076d
294          U+01800 - U+01805
295          U+01d00 - U+01d77
296          U+01d9b - U+01dbf
297          U+0200b - U+0200f
298          U+030fc - U+030fe
299          U+03260 - U+0327f
300          U+0fb46 - U+0fbb1
301          U+10450 - U+1049d
302    
303    12. The -o option (show only the matching part of a line) for pcregrep was not
304        compatible with GNU grep in that, if there was more than one match in a
305        line, it showed only the first of them. It now behaves in the same way as
306        GNU grep.
307    
308    13. If the -o and -v options were combined for pcregrep, it printed a blank
309        line for every non-matching line. GNU grep prints nothing, and pcregrep now
310        does the same. The return code can be used to tell if there were any
311        non-matching lines.
312    
313    14. Added --file-offsets and --line-offsets to pcregrep.
314    
315    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
316        infinitely looping recursion. The bug was that positive lookaheads were not
317        being skipped when checking for a possible empty match (negative lookaheads
318        and both kinds of lookbehind were skipped).
319    
320    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
321        inclusion of <windows.h> to before rather than after the definition of
322        INVALID_FILE_ATTRIBUTES (patch from David Byron).
323    
324    17. Specifying a possessive quantifier with a specific limit for a Unicode
325        character property caused pcre_compile() to compile bad code, which led at
326        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
327        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
328        caused the error; without that there was no problem.
329    
330    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
331    
332    19. Added --enable-pcretest-libreadline.
333    
334    20. In pcrecpp.cc, the variable 'count' was incremented twice in
335        RE::GlobalReplace(). As a result, the number of replacements returned was
336        double what it should be. I removed one of the increments, but Craig sent a
337        later patch that removed the other one (the right fix) and added unit tests
338        that check the return values (which was not done before).
339    
340    21. Several CMake things:
341    
342        (1) Arranged that, when cmake is used on Unix, the libraries end up with
343            the names libpcre and libpcreposix, not just pcre and pcreposix.
344    
345        (2) The above change means that pcretest and pcregrep are now correctly
346            linked with the newly-built libraries, not previously installed ones.
347    
348        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
349    
350    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
351        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
352        UTF-8 newline character). The key issue is that the pattern starts .*;
353        this means that the match must be either at the beginning, or after a
354        newline. The bug was in the code for advancing after a failed match and
355        checking that the new position followed a newline. It was not taking
356        account of UTF-8 characters correctly.
357    
358    23. PCRE was behaving differently from Perl in the way it recognized POSIX
359        character classes. PCRE was not treating the sequence [:...:] as a
360        character class unless the ... were all letters. Perl, however, seems to
361        allow any characters between [: and :], though of course it rejects as
362        unknown any "names" that contain non-letters, because all the known class
363        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
364        for example, whereas PCRE did not - it did not recognize a POSIX character
365        class. This seemed a bit dangerous, so the code has been changed to be
366        closer to Perl. The behaviour is not identical to Perl, because PCRE will
367        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
368        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
369        Perl does, and where it didn't before.
370    
371    24. Rewrite so as to remove the single use of %n from pcregrep because in some
372        Windows environments %n is disabled by default.
373    
374    
375    Version 7.4 21-Sep-07
376    ---------------------
377    
378    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
379        means that a class such as [\s] counted as "explicit reference to CR or
380        LF". That isn't really right - the whole point of the change was to try to
381        help when there was an actual mention of one of the two characters. So now
382        the change happens only if \r or \n (or a literal CR or LF) character is
383        encountered.
384    
385    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
386        of both had grown to the point where there were only 3 bits left.
387        Fortunately, there was spare space in the data structure, and so I have
388        moved the internal flags into a new 16-bit field to free up more option
389        bits.
390    
391    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
392        but did not set the internal JCHANGED flag - either of these is enough to
393        control the way the "get" function works - but the PCRE_INFO_JCHANGED
394        facility is supposed to tell if (?J) was ever used, so now (?J) at the
395        start sets both bits.
396    
397    4.  Added options (at build time, compile time, exec time) to change \R from
398        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
399    
400    5.  doc/pcresyntax.html was missing from the distribution.
401    
402    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
403        compatibility, even though it is no longer used.
404    
405    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
406        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
407        windows.h file is present (where different names are used). [This was
408        reversed later after testing - see 16 below.]
409    
410    8.  Changed all #include <config.h> to #include "config.h". There were also
411        some further <pcre.h> cases that I changed to "pcre.h".
412    
413    9.  When pcregrep was used with the --colour option, it missed the line ending
414        sequence off the lines that it output.
415    
416    10. It was pointed out to me that arrays of string pointers cause lots of
417        relocations when a shared library is dynamically loaded. A technique of
418        using a single long string with a table of offsets can drastically reduce
419        these. I have refactored PCRE in four places to do this. The result is
420        dramatic:
421    
422          Originally:                          290
423          After changing UCP table:            187
424          After changing error message table:   43
425          After changing table of "verbs"       36
426          After changing table of Posix names   22
427    
428        Thanks to the folks working on Gregex for glib for this insight.
429    
430    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
431        unicode-properties was also set.
432    
433    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
434    
435    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
436        checked only for CRLF.
437    
438    14. Added casts to pcretest.c to avoid compiler warnings.
439    
440    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
441    
442    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
443        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
444        entirely. This removes changes made in 7 above.
445    
446    17. The CMake files have been updated, and there is now more information about
447        building with CMake in the NON-UNIX-USE document.
448    
449    
450    Version 7.3 28-Aug-07
451    ---------------------
452    
453     1. In the rejigging of the build system that eventually resulted in 7.1, the
454        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
455        brackets there is not right, since it causes compilers to look for an
456        installed pcre.h, not the version that is in the source that is being
457        compiled (which of course may be different). I have changed it back to:
458    
459          #include "pcre.h"
460    
461        I have a vague recollection that the change was concerned with compiling in
462        different directories, but in the new build system, that is taken care of
463        by the VPATH setting the Makefile.
464    
465     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
466        when the subject happened to end in the byte 0x85 (e.g. if the last
467        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
468        characters but of course it shouldn't be taken as a newline when it is part
469        of another character. The bug was that, for an unlimited repeat of . in
470        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
471        characters when looking for a newline.
472    
473     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
474    
475     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
476        in debug output.
477    
478     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
479        long printing in the pcrecpp unittest when running under MinGW.
480    
481     6. ESC_K was left out of the EBCDIC table.
482    
483     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
484        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
485        limit also applies to "virtual nesting" when a pattern is recursive, and in
486        this case 1000 isn't so big. I have been able to remove this limit at the
487        expense of backing off one optimization in certain circumstances. Normally,
488        when pcre_exec() would call its internal match() function recursively and
489        immediately return the result unconditionally, it uses a "tail recursion"
490        feature to save stack. However, when a subpattern that can match an empty
491        string has an unlimited repetition quantifier, it no longer makes this
492        optimization. That gives it a stack frame in which to save the data for
493        checking that an empty string has been matched. Previously this was taken
494        from the 1000-entry workspace that had been reserved. So now there is no
495        explicit limit, but more stack is used.
496    
497     8. Applied Daniel's patches to solve problems with the import/export magic
498        syntax that is required for Windows, and which was going wrong for the
499        pcreposix and pcrecpp parts of the library. These were overlooked when this
500        problem was solved for the main library.
501    
502     9. There were some crude static tests to avoid integer overflow when computing
503        the size of patterns that contain repeated groups with explicit upper
504        limits. As the maximum quantifier is 65535, the maximum group length was
505        set at 30,000 so that the product of these two numbers did not overflow a
506        32-bit integer. However, it turns out that people want to use groups that
507        are longer than 30,000 bytes (though not repeat them that many times).
508        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
509        made it possible to implement the integer overflow checks in a much more
510        dynamic way, which I have now done. The artificial limitation on group
511        length has been removed - we now have only the limit on the total length of
512        the compiled pattern, which depends on the LINK_SIZE setting.
513    
514    10. Fixed a bug in the documentation for get/copy named substring when
515        duplicate names are permitted. If none of the named substrings are set, the
516        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
517        empty string.
518    
519    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
520        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
521        because the ] is interpreted as the first data character and the
522        terminating ] is not found. PCRE has been made compatible with Perl in this
523        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
524        cause memory overwriting.
525    
526    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
527        string has been matched (to stop an infinite loop). It was not recognizing
528        a conditional subpattern that could match an empty string if that
529        subpattern was within another subpattern. For example, it looped when
530        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
531        condition was not nested. This bug has been fixed.
532    
533    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
534        past the start of the subject in the presence of bytes with the top bit
535        set, for example "\x8aBCD".
536    
537    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
538        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
539    
540    14. Optimized (?!) to (*FAIL).
541    
542    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
543        This restricts code points to be within the range 0 to 0x10FFFF, excluding
544        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
545        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
546        does: it's just the validity check that is more restrictive.
547    
548    16. Inserted checks for integer overflows during escape sequence (backslash)
549        processing, and also fixed erroneous offset values for syntax errors during
550        backslash processing.
551    
552    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
553        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
554    
555    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
556        caused an overrun.
557    
558    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
559        something other than just ASCII characters) inside a group that had an
560        unlimited repeat caused a loop at compile time (while checking to see
561        whether the group could match an empty string).
562    
563    20. Debugging a pattern containing \p or \P could cause a crash. For example,
564        [\P{Any}] did so. (Error in the code for printing property names.)
565    
566    21. An orphan \E inside a character class could cause a crash.
567    
568    22. A repeated capturing bracket such as (A)? could cause a wild memory
569        reference during compilation.
570    
571    23. There are several functions in pcre_compile() that scan along a compiled
572        expression for various reasons (e.g. to see if it's fixed length for look
573        behind). There were bugs in these functions when a repeated \p or \P was
574        present in the pattern. These operators have additional parameters compared
575        with \d, etc, and these were not being taken into account when moving along
576        the compiled data. Specifically:
577    
578        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
579            length.
580    
581        (b) An item such as \pL+ within a repeated group could cause crashes or
582            loops.
583    
584        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
585            "reference to non-existent subpattern" error.
586    
587        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
588    
589    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
590        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
591    
592    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
593    
594    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
595        character were causing crashes (broken optimization).
596    
597    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
598        \p or \P) caused a compile-time loop.
599    
600    28. More problems have arisen in unanchored patterns when CRLF is a valid line
601        break. For example, the unstudied pattern [\r\n]A does not match the string
602        "\r\nA" because change 7.0/46 below moves the current point on by two
603        characters after failing to match at the start. However, the pattern \nA
604        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
605        the same is true. There doesn't seem any very clean way out of this, but
606        what I have chosen to do makes the common cases work: PCRE now takes note
607        of whether there can be an explicit match for \r or \n anywhere in the
608        pattern, and if so, 7.0/46 no longer applies. As part of this change,
609        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
610        pattern has explicit CR or LF references.
611    
612    29. Added (*CR) etc for changing newline setting at start of pattern.
613    
614    
615    Version 7.2 19-Jun-07
616    ---------------------
617    
618     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
619        which is apparently normally available under Windows.
620    
621     2. Re-jig the pcregrep tests with different newline settings in an attempt
622        to make them independent of the local environment's newline setting.
623    
624     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
625    
626     4. Some of the "internals" tests were previously cut out when the link size
627        was not 2, because the output contained actual offsets. The recent new
628        "Z" feature of pcretest means that these can be cut out, making the tests
629        usable with all link sizes.
630    
631     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
632        stack recursion. This gives a massive performance boost under BSD, but just
633        a small improvement under Linux. However, it saves one field in the frame
634        in all cases.
635    
636     6. Added more features from the forthcoming Perl 5.10:
637    
638        (a) (?-n) (where n is a string of digits) is a relative subroutine or
639            recursion call. It refers to the nth most recently opened parentheses.
640    
641        (b) (?+n) is also a relative subroutine call; it refers to the nth next
642            to be opened parentheses.
643    
644        (c) Conditions that refer to capturing parentheses can be specified
645            relatively, for example, (?(-2)... or (?(+3)...
646    
647        (d) \K resets the start of the current match so that everything before
648            is not part of it.
649    
650        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
651    
652        (f) \g{name} is another synonym - part of Perl 5.10's unification of
653            reference syntax.
654    
655        (g) (?| introduces a group in which the numbering of parentheses in each
656            alternative starts with the same number.
657    
658        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
659    
660     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
661        PCRE_INFO_JCHANGED.
662    
663     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
664        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
665        for detecting groups that can match an empty string.
666    
667     9. A pattern with a very large number of alternatives (more than several
668        hundred) was running out of internal workspace during the pre-compile
669        phase, where pcre_compile() figures out how much memory will be needed. A
670        bit of new cunning has reduced the workspace needed for groups with
671        alternatives. The 1000-alternative test pattern now uses 12 bytes of
672        workspace instead of running out of the 4096 that are available.
673    
674    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
675    
676    11. Applied patch from Google to remove an optimization that didn't quite work.
677        The report of the bug said:
678    
679          pcrecpp::RE("a*").FullMatch("aaa") matches, while
680          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
681          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
682    
683    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
684        it matched the wrong number of bytes.
685    
686    
687    Version 7.1 24-Apr-07
688    ---------------------
689    
690     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
691        that is more "standard", making use of automake and other Autotools. There
692        is some re-arrangement of the files and adjustment of comments consequent
693        on this.
694    
695     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
696        for recursive directory scanning broke on some systems because the files
697        are not scanned in any specific order and on different systems the order
698        was different. A call to "sort" has been inserted into RunGrepTest for the
699        approprate test as a short-term fix. In the longer term there may be an
700        alternative.
701    
702     3. I had an email from Eric Raymond about problems translating some of PCRE's
703        man pages to HTML (despite the fact that I distribute HTML pages, some
704        people do their own conversions for various reasons). The problems
705        concerned the use of low-level troff macros .br and .in. I have therefore
706        removed all such uses from the man pages (some were redundant, some could
707        be replaced by .nf/.fi pairs). The 132html script that I use to generate
708        HTML has been updated to handle .nf/.fi and to complain if it encounters
709        .br or .in.
710    
711     4. Updated comments in configure.ac that get placed in config.h.in and also
712        arranged for config.h to be included in the distribution, with the name
713        config.h.generic, for the benefit of those who have to compile without
714        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
715    
716     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
717        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
718        makevp.bat for the current PCRE, using the additional files
719        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
720    
721     6. A Windows user reported a minor discrepancy with test 2, which turned out
722        to be caused by a trailing space on an input line that had got lost in his
723        copy. The trailing space was an accident, so I've just removed it.
724    
725     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
726        that is needed.
727    
728     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
729        as "const" (a) because they are and (b) because it helps the PHP
730        maintainers who have recently made a script to detect big data structures
731        in the php code that should be moved to the .rodata section. I remembered
732        to update Builducptable as well, so it won't revert if ucptable.h is ever
733        re-created.
734    
735     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
736        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
737        order to be able to cut out the UTF-8 tables in the latter when UTF-8
738        support is not required. This saves 1.5-2K of code, which is important in
739        some applications.
740    
741        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
742        so as not to refer to the tables, even though these functions will never be
743        called when UTF-8 support is disabled. Otherwise there are problems with a
744        shared library.
745    
746    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
747    
748        (a) It was defining its arguments as char * instead of void *.
749    
750        (b) It was assuming that all moves were upwards in memory; this was true
751            a long time ago when I wrote it, but is no longer the case.
752    
753        The emulated memove() is provided for those environments that have neither
754        memmove() nor bcopy(). I didn't think anyone used it these days, but that
755        is clearly not the case, as these two bugs were recently reported.
756    
757    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
758        and Detrail to create the HTML documentation, the .txt form of the man
759        pages, and it removes trailing spaces from listed files. It also creates
760        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
761        case, it wraps all the #defines with #ifndefs. This script should be run
762        before "make dist".
763    
764    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
765        with Unicode property support.
766    
767        (a) For a maximizing quantifier, if the two different cases of the
768            character were of different lengths in their UTF-8 codings (there are
769            some cases like this - I found 11), and the matching function had to
770            back up over a mixture of the two cases, it incorrectly assumed they
771            were both the same length.
772    
773        (b) When PCRE was configured to use the heap rather than the stack for
774            recursion during matching, it was not correctly preserving the data for
775            the other case of a UTF-8 character when checking ahead for a match
776            while processing a minimizing repeat. If the check also involved
777            matching a wide character, but failed, corruption could cause an
778            erroneous result when trying to check for a repeat of the original
779            character.
780    
781    13. Some tidying changes to the testing mechanism:
782    
783        (a) The RunTest script now detects the internal link size and whether there
784            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
785            values substituted by "configure". (The RunGrepTest script already did
786            this for UTF-8.) The configure.ac script no longer substitutes the
787            relevant variables.
788    
789        (b) The debugging options /B and /D in pcretest show the compiled bytecode
790            with length and offset values. This means that the output is different
791            for different internal link sizes. Test 2 is skipped for link sizes
792            other than 2 because of this, bypassing the problem. Unfortunately,
793            there was also a test in test 3 (the locale tests) that used /B and
794            failed for link sizes other than 2. Rather than cut the whole test out,
795            I have added a new /Z option to pcretest that replaces the length and
796            offset values with spaces. This is now used to make test 3 independent
797            of link size. (Test 2 will be tidied up later.)
798    
799    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
800        segmentation fault instead of returning the appropriate error message.
801    
802    15. In multiline mode when the newline sequence was set to "any", the pattern
803        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
804        This doesn't seem right; it now treats the CRLF combination as the line
805        ending, and so does not match in that case. It's only a pattern such as ^$
806        that would hit this one: something like ^ABC$ would have failed after \r
807        and then tried again after \r\n.
808    
809    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
810        in an attempt to make files that differ only in their line terminators
811        compare equal. This works on Linux.
812    
813    17. Under certain error circumstances pcregrep might try to free random memory
814        as it exited. This is now fixed, thanks to valgrind.
815    
816    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
817        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
818        was because its rules for how to advance for /g after matching an empty
819        string at the end of a line did not allow for this case. They now check for
820        it specially.
821    
822    20. pcretest is supposed to handle patterns and data of any length, by
823        extending its buffers when necessary. It was getting this wrong when the
824        buffer for a data line had to be extended.
825    
826    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
827        CRLF as a newline sequence.
828    
829    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
830        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
831        I have nevertheless tidied it up.
832    
833    23. Added some casts to kill warnings from HP-UX ia64 compiler.
834    
835    24. Added a man page for pcre-config.
836    
837    
838    Version 7.0 19-Dec-06
839    ---------------------
840    
841     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
842        moving to gcc 4.1.1.
843    
844     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
845        sys/time.h, which is documented as needed for this function. It doesn't
846        seem to matter on Linux, but it showed up on some releases of OS X.
847    
848     3. It seems that there are systems where bytes whose values are greater than
849        127 match isprint() in the "C" locale. The "C" locale should be the
850        default when a C program starts up. In most systems, only ASCII printing
851        characters match isprint(). This difference caused the output from pcretest
852        to vary, making some of the tests fail. I have changed pcretest so that:
853    
854        (a) When it is outputting text in the compiled version of a pattern, bytes
855            other than 32-126 are always shown as hex escapes.
856    
857        (b) When it is outputting text that is a matched part of a subject string,
858            it does the same, unless a different locale has been set for the match
859            (using the /L modifier). In this case, it uses isprint() to decide.
860    
861     4. Fixed a major bug that caused incorrect computation of the amount of memory
862        required for a compiled pattern when options that changed within the
863        pattern affected the logic of the preliminary scan that determines the
864        length. The relevant options are -x, and -i in UTF-8 mode. The result was
865        that the computed length was too small. The symptoms of this bug were
866        either the PCRE error "internal error: code overflow" from pcre_compile(),
867        or a glibc crash with a message such as "pcretest: free(): invalid next
868        size (fast)". Examples of patterns that provoked this bug (shown in
869        pcretest format) are:
870    
871          /(?-x: )/x
872          /(?x)(?-x: \s*#\s*)/
873          /((?i)[\x{c0}])/8
874          /(?i:[\x{c0}])/8
875    
876        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
877        is now done differently.
878    
879     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
880        wrapper classes; (b) implement a new function in the C++ scanner that is
881        more efficient than the old way of doing things because it avoids levels of
882        recursion in the regex matching; (c) add a paragraph to the documentation
883        for the FullMatch() function.
884    
885     6. The escape sequence \n was being treated as whatever was defined as
886        "newline". Not only was this contrary to the documentation, which states
887        that \n is character 10 (hex 0A), but it also went horribly wrong when
888        "newline" was defined as CRLF. This has been fixed.
889    
890     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
891        was being set to -1 for the "end of line" case (supposedly a value that no
892        character can have). Though this value is never used (the check for end of
893        line is "zero bytes in current character"), it caused compiler complaints.
894        I've changed it to 0xffffffff.
895    
896     8. In pcre_version.c, the version string was being built by a sequence of
897        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
898        string (as it is for production releases) called a macro with an empty
899        argument. The C standard says the result of this is undefined. The gcc
900        compiler treats it as an empty string (which was what was wanted) but it is
901        reported that Visual C gives an error. The source has been hacked around to
902        avoid this problem.
903    
904     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
905        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
906        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
907        of them did).
908    
909    10. Originally, pcretest opened its input and output without "b"; then I was
910        told that "b" was needed in some environments, so it was added for release
911        5.0 to both the input and output. (It makes no difference on Unix-like
912        systems.) Later I was told that it is wrong for the input on Windows. I've
913        now abstracted the modes into two macros, to make it easier to fiddle with
914        them, and removed "b" from the input mode under Windows.
915    
916    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
917    
918    12. Added -help and --help to pcretest as an official way of being reminded
919        of the options.
920    
921    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
922        and pcrecpp.cc because they annoy compilers at high warning levels.
923    
924    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
925    
926    15. Fixed an occurrence of == in configure.ac that should have been = (shell
927        scripts are not C programs :-) and which was not noticed because it works
928        on Linux.
929    
930    16. pcretest is supposed to handle any length of pattern and data line (as one
931        line or as a continued sequence of lines) by extending its input buffer if
932        necessary. This feature was broken for very long pattern lines, leading to
933        a string of junk being passed to pcre_compile() if the pattern was longer
934        than about 50K.
935    
936    17. I have done a major re-factoring of the way pcre_compile() computes the
937        amount of memory needed for a compiled pattern. Previously, there was code
938        that made a preliminary scan of the pattern in order to do this. That was
939        OK when PCRE was new, but as the facilities have expanded, it has become
940        harder and harder to keep it in step with the real compile phase, and there
941        have been a number of bugs (see for example, 4 above). I have now found a
942        cunning way of running the real compile function in a "fake" mode that
943        enables it to compute how much memory it would need, while actually only
944        ever using a few hundred bytes of working memory and without too many
945        tests of the mode. This should make future maintenance and development
946        easier. A side effect of this work is that the limit of 200 on the nesting
947        depth of parentheses has been removed (though this was never a serious
948        limitation, I suspect). However, there is a downside: pcre_compile() now
949        runs more slowly than before (30% or more, depending on the pattern). I
950        hope this isn't a big issue. There is no effect on runtime performance.
951    
952    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
953        newline (only possible for the last line of a file) and it was a
954        pattern that set a locale (followed by /Lsomething), pcretest crashed.
955    
956    19. Added additional timing features to pcretest. (1) The -tm option now times
957        matching only, not compiling. (2) Both -t and -tm can be followed, as a
958        separate command line item, by a number that specifies the number of
959        repeats to use when timing. The default is 50000; this gives better
960        precision, but takes uncomfortably long for very large patterns.
961    
962    20. Extended pcre_study() to be more clever in cases where a branch of a
963        subpattern has no definite first character. For example, (a*|b*)[cd] would
964        previously give no result from pcre_study(). Now it recognizes that the
965        first character must be a, b, c, or d.
966    
967    21. There was an incorrect error "recursive call could loop indefinitely" if
968        a subpattern (or the entire pattern) that was being tested for matching an
969        empty string contained only one non-empty item after a nested subpattern.
970        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
971        incorrectly, because the \d was being skipped in the check.
972    
973    22. The pcretest program now has a new pattern option /B and a command line
974        option -b, which is equivalent to adding /B to every pattern. This causes
975        it to show the compiled bytecode, without the additional information that
976        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
977        is the same as /B/I).
978    
979    23. A new optimization is now able automatically to treat some sequences such
980        as a*b as a*+b. More specifically, if something simple (such as a character
981        or a simple class like \d) has an unlimited quantifier, and is followed by
982        something that cannot possibly match the quantified thing, the quantifier
983        is automatically "possessified".
984    
985    24. A recursive reference to a subpattern whose number was greater than 39
986        went wrong under certain circumstances in UTF-8 mode. This bug could also
987        have affected the operation of pcre_study().
988    
989    25. Realized that a little bit of performance could be had by replacing
990        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
991    
992    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
993    
994    27. Possessive quantifiers such as a++ were previously implemented by turning
995        them into atomic groups such as ($>a+). Now they have their own opcodes,
996        which improves performance. This includes the automatically created ones
997        from 23 above.
998    
999    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1000        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1001        the first matched character to be a colon. This applied both to named and
1002        numbered groups.
1003    
1004    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1005    
1006    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1007        building PCRE on Windows easier, so I have included it in the distribution.
1008    
1009    31. There is now a check in pcretest against a ridiculously large number being
1010        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1011        loop, the loop is abandoned.
1012    
1013    32. Forward references to subpatterns in conditions such as (?(2)...) where
1014        subpattern 2 is defined later cause pcre_compile() to search forwards in
1015        the pattern for the relevant set of parentheses. This search went wrong
1016        when there were unescaped parentheses in a character class, parentheses
1017        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1018    
1019    33. "Subroutine" calls and backreferences were previously restricted to
1020        referencing subpatterns earlier in the regex. This restriction has now
1021        been removed.
1022    
1023    34. Added a number of extra features that are going to be in Perl 5.10. On the
1024        whole, these are just syntactic alternatives for features that PCRE had
1025        previously implemented using the Python syntax or my own invention. The
1026        other formats are all retained for compatibility.
1027    
1028        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1029            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1030            also .NET compatible.
1031    
1032        (b) A recursion or subroutine call to a named group can now be defined as
1033            (?&name) as well as (?P>name).
1034    
1035        (c) A backreference to a named group can now be defined as \k<name> or
1036            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1037            5.10, are also .NET compatible.
1038    
1039        (d) A conditional reference to a named group can now use the syntax
1040            (?(<name>) or (?('name') as well as (?(name).
1041    
1042        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1043            groups (named and numbered) that are never evaluated inline, but can be
1044            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1045            is always false. There may be only one alternative in such a group.
1046    
1047        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1048            as the simple (?(R). The condition is true only if the most recent
1049            recursion is that of the given number or name. It does not search out
1050            through the entire recursion stack.
1051    
1052        (g) The escape \gN or \g{N} has been added, where N is a positive or
1053            negative number, specifying an absolute or relative reference.
1054    
1055    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1056        some "unreachable code" warnings.
1057    
1058    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1059        things, this adds five new scripts.
1060    
1061    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1062        There were also incompatibilities regarding the handling of \Q..\E inside
1063        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1064        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1065    
1066    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1067        matches an empty string, and forcibly breaks the loop. There were bugs in
1068        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1069        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1070        separate and independent bugs (that affected different cases) have been
1071        fixed.
1072    
1073    39. Refactored the code to abolish the use of different opcodes for small
1074        capturing bracket numbers. This is a tidy that I avoided doing when I
1075        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1076        The new approach is not only tidier, it makes it possible to reduce the
1077        memory needed to fix the previous bug (38).
1078    
1079    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1080        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1081        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1082        mode.
1083    
1084    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1085        report.
1086    
1087    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1088        copy construction and assignment in the C++ wrapper.
1089    
1090    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1091        couple of bugs that could have given wrong results in the "--newline=crlf"
1092        case.
1093    
1094    44. Added a number of casts and did some reorganization of signed/unsigned int
1095        variables following suggestions from Dair Grant. Also renamed the variable
1096        "this" as "item" because it is a C++ keyword.
1097    
1098    45. Arranged for dftables to add
1099    
1100          #include "pcre_internal.h"
1101    
1102        to pcre_chartables.c because without it, gcc 4.x may remove the array
1103        definition from the final binary if PCRE is built into a static library and
1104        dead code stripping is activated.
1105    
1106    46. For an unanchored pattern, if a match attempt fails at the start of a
1107        newline sequence, and the newline setting is CRLF or ANY, and the next two
1108        characters are CRLF, advance by two characters instead of one.
1109    
1110    
1111    Version 6.7 04-Jul-06
1112    ---------------------
1113    
1114     1. In order to handle tests when input lines are enormously long, pcretest has
1115        been re-factored so that it automatically extends its buffers when
1116        necessary. The code is crude, but this _is_ just a test program. The
1117        default size has been increased from 32K to 50K.
1118    
1119     2. The code in pcre_study() was using the value of the re argument before
1120        testing it for NULL. (Of course, in any sensible call of the function, it
1121        won't be NULL.)
1122    
1123     3. The memmove() emulation function in pcre_internal.h, which is used on
1124        systems that lack both memmove() and bcopy() - that is, hardly ever -
1125        was missing a "static" storage class specifier.
1126    
1127     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1128        containing an extended class (one that cannot be represented by a bitmap
1129        because it contains high-valued characters or Unicode property items, e.g.
1130        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1131        pattern, but PCRE should not loop if you do not (it no longer does).
1132        [Detail: two cases were found: (a) a repeated subpattern containing an
1133        extended class; (b) a recursive reference to a subpattern that followed a
1134        previous extended class. It wasn't skipping over the extended class
1135        correctly when UTF-8 mode was not set.]
1136    
1137     5. A negated single-character class was not being recognized as fixed-length
1138        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1139        compile error "lookbehind assertion is not fixed length".
1140    
1141     6. The RunPerlTest auxiliary script was showing an unexpected difference
1142        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1143        write a Perl script that can interpret lines of an input file either as
1144        byte characters or as UTF-8, which is what "perltest" was being required to
1145        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1146        can't do is switch easily at run time between having the "use utf8;" pragma
1147        or not. In the end, I fudged it by using the RunPerlTest script to insert
1148        "use utf8;" explicitly for the UTF-8 tests.
1149    
1150     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1151        the end of the subject string, contrary to the documentation and to what
1152        Perl does. This was true of both matching functions. Now it matches only at
1153        the start of the subject and immediately after *internal* newlines.
1154    
1155     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1156        a pointer to an int instead of a pointer to an unsigned long int. This
1157        caused problems on 64-bit systems.
1158    
1159     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1160        instance of the 'standard' template library not being so standard".
1161    
1162    10. There was no check on the number of named subpatterns nor the maximum
1163        length of a subpattern name. The product of these values is used to compute
1164        the size of the memory block for a compiled pattern. By supplying a very
1165        long subpattern name and a large number of named subpatterns, the size
1166        computation could be caused to overflow. This is now prevented by limiting
1167        the length of names to 32 characters, and the number of named subpatterns
1168        to 10,000.
1169    
1170    11. Subpatterns that are repeated with specific counts have to be replicated in
1171        the compiled pattern. The size of memory for this was computed from the
1172        length of the subpattern and the repeat count. The latter is limited to
1173        65535, but there was no limit on the former, meaning that integer overflow
1174        could in principle occur. The compiled length of a repeated subpattern is
1175        now limited to 30,000 bytes in order to prevent this.
1176    
1177    12. Added the optional facility to have named substrings with the same name.
1178    
1179    13. Added the ability to use a named substring as a condition, using the
1180        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1181        are numbers (not recommended). Forward references are permitted.
1182    
1183    14. Added forward references in named backreferences (if you see what I mean).
1184    
1185    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1186        pattern could run off the end of the subject. For example, the pattern
1187        "(?s)(.{1,5})"8 did this with the subject "ab".
1188    
1189    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1190        PCRE_CASELESS was set when matching characters that were quantified with ?
1191        or *.
1192    
1193    17. A character class other than a single negated character that had a minimum
1194        but no maximum quantifier - for example [ab]{6,} - was not handled
1195        correctly by pce_dfa_exec(). It would match only one character.
1196    
1197    18. A valid (though odd) pattern that looked like a POSIX character
1198        class but used an invalid character after [ (for example [[,abc,]]) caused
1199        pcre_compile() to give the error "Failed: internal error: code overflow" or
1200        in some cases to crash with a glibc free() error. This could even happen if
1201        the pattern terminated after [[ but there just happened to be a sequence of
1202        letters, a binary zero, and a closing ] in the memory that followed.
1203    
1204    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1205        over the years. Originally (before any Unicode support), just the bottom 8
1206        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1207        output from "man perlunicode" includes this:
1208    
1209          The regular expression compiler produces polymorphic opcodes.  That
1210          is, the pattern adapts to the data and automatically switches to
1211          the Unicode character scheme when presented with Unicode data--or
1212          instead uses a traditional byte scheme when presented with byte
1213          data.
1214    
1215        Sadly, a wide octal escape does not cause a switch, and in a string with
1216        no other multibyte characters, these octal escapes are treated as before.
1217        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1218        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1219        Unicode string.
1220    
1221        I have not perpetrated such confusion in PCRE. Up till now, it took just
1222        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1223        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1224        translate to the appropriate multibyte character.
1225    
1226    29. Applied some refactoring to reduce the number of warnings from Microsoft
1227        and Borland compilers. This has included removing the fudge introduced
1228        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1229        a warning about an unused variable.
1230    
1231    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1232        characters since release 4.0, because Perl (from release 5.004) does not.
1233        [Or at least, is documented not to: some releases seem to be in conflict
1234        with the documentation.] However, when a pattern was studied with
1235        pcre_study() and all its branches started with \s, PCRE still included VT
1236        as a possible starting character. Of course, this did no harm; it just
1237        caused an unnecessary match attempt.
1238    
1239    22. Removed a now-redundant internal flag bit that recorded the fact that case
1240        dependency changed within the pattern. This was once needed for "required
1241        byte" processing, but is no longer used. This recovers a now-scarce options
1242        bit. Also moved the least significant internal flag bit to the most-
1243        significant bit of the word, which was not previously used (hangover from
1244        the days when it was an int rather than a uint) to free up another bit for
1245        the future.
1246    
1247    23. Added support for CRLF line endings as well as CR and LF. As well as the
1248        default being selectable at build time, it can now be changed at runtime
1249        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1250        specify that it is scanning data with non-default line endings.
1251    
1252    24. Changed the definition of CXXLINK to make it agree with the definition of
1253        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1254    
1255    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1256        recursions. This makes a big different to stack usage for some patterns.
1257    
1258    26. If a subpattern containing a named recursion or subroutine reference such
1259        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1260        the space required for the compiled pattern went wrong and gave too small a
1261        value. Depending on the environment, this could lead to "Failed: internal
1262        error: code overflow at offset 49" or "glibc detected double free or
1263        corruption" errors.
1264    
1265    27. Applied patches from Google (a) to support the new newline modes and (b) to
1266        advance over multibyte UTF-8 characters in GlobalReplace.
1267    
1268    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1269        difference for some implementation of PCRE in some Windows version.
1270    
1271    29. Added some extra testing facilities to pcretest:
1272    
1273        \q<number>   in a data line sets the "match limit" value
1274        \Q<number>   in a data line sets the "match recursion limt" value
1275        -S <number>  sets the stack size, where <number> is in megabytes
1276    
1277        The -S option isn't available for Windows.
1278    
1279    
1280    Version 6.6 06-Feb-06
1281    ---------------------
1282    
1283     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1284        in pcreposix.h. I have copied the definition from pcre.h.
1285    
1286     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1287        because pcre.h is no longer a built file.
1288    
1289     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1290        not normally included in the compiled code.
1291    
1292    
1293    Version 6.5 01-Feb-06
1294    ---------------------
1295    
1296     1. When using the partial match feature with pcre_dfa_exec(), it was not
1297        anchoring the second and subsequent partial matches at the new starting
1298        point. This could lead to incorrect results. For example, with the pattern
1299        /1234/, partially matching against "123" and then "a4" gave a match.
1300    
1301     2. Changes to pcregrep:
1302    
1303        (a) All non-match returns from pcre_exec() were being treated as failures
1304            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1305            error message is output. Some extra information is given for the
1306            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1307            probably the only errors that are likely to be caused by users (by
1308            specifying a regex that has nested indefinite repeats, for instance).
1309            If there are more than 20 of these errors, pcregrep is abandoned.
1310    
1311        (b) A binary zero was treated as data while matching, but terminated the
1312            output line if it was written out. This has been fixed: binary zeroes
1313            are now no different to any other data bytes.
1314    
1315        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1316            used to set a locale for matching. The --locale=xxxx long option has
1317            been added (no short equivalent) to specify a locale explicitly on the
1318            pcregrep command, overriding the environment variables.
1319    
1320        (d) When -B was used with -n, some line numbers in the output were one less
1321            than they should have been.
1322    
1323        (e) Added the -o (--only-matching) option.
1324    
1325        (f) If -A or -C was used with -c (count only), some lines of context were
1326            accidentally printed for the final match.
1327    
1328        (g) Added the -H (--with-filename) option.
1329    
1330        (h) The combination of options -rh failed to suppress file names for files
1331            that were found from directory arguments.
1332    
1333        (i) Added the -D (--devices) and -d (--directories) options.
1334    
1335        (j) Added the -F (--fixed-strings) option.
1336    
1337        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1338    
1339        (l) Added the --colo(u)r option.
1340    
1341        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1342            is not present by default.
1343    
1344     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1345        items such as (?R) or (?1), when the recursion could match a number of
1346        alternatives. If it matched one of the alternatives, but subsequently,
1347        outside the recursion, there was a failure, the code tried to back up into
1348        the recursion. However, because of the way PCRE is implemented, this is not
1349        possible, and the result was an incorrect result from the match.
1350    
1351        In order to prevent this happening, the specification of recursion has
1352        been changed so that all such subpatterns are automatically treated as
1353        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1354    
1355     4. I had overlooked the fact that, in some locales, there are characters for
1356        which isalpha() is true but neither isupper() nor islower() are true. In
1357        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1358        and ordfeminine) are like this. This affected the treatment of \w and \W
1359        when they appeared in character classes, but not when they appeared outside
1360        a character class. The bit map for "word" characters is now created
1361        separately from the results of isalnum() instead of just taking it from the
1362        upper, lower, and digit maps. (Plus the underscore character, of course.)
1363    
1364     5. The above bug also affected the handling of POSIX character classes such as
1365        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1366        permanent tables. Instead, the bit maps for such a class were previously
1367        created as the appropriate unions of the upper, lower, and digit bitmaps.
1368        Now they are created by subtraction from the [[:word:]] class, which has
1369        its own bitmap.
1370    
1371     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1372        It is created by subtracting the vertical space characters (\x09, \x0a,
1373        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1374        subtraction was done in the overall bitmap for a character class, meaning
1375        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1376        be recognized. This bug has been fixed.
1377    
1378     7. Patches from the folks at Google:
1379    
1380          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1381          real life, but is still worth protecting against".
1382    
1383          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1384          regular expressions".
1385    
1386          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1387          have it.
1388    
1389          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1390          "configure" and the latter not, in order to fix a problem somebody had
1391          with compiling the Arg class on HP-UX.
1392    
1393          (e) Improve the error-handling of the C++ wrapper a little bit.
1394    
1395          (f) New tests for checking recursion limiting.
1396    
1397     8. The pcre_memmove() function, which is used only if the environment does not
1398        have a standard memmove() function (and is therefore rarely compiled),
1399        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1400        returning a result (though PCRE never actually uses the result).
1401    
1402     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1403        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1404        returned instead of calling malloc() with an overflowing number that would
1405        most likely cause subsequent chaos.
1406    
1407    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1408    
1409    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1410        with this option is matched, the nmatch and pmatch options of regexec() are
1411        ignored.
1412    
1413    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1414        provided in case anyone wants to the the POSIX interface with UTF-8
1415        strings.
1416    
1417    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1418        C++ linking (needed for some HP-UX environments).
1419    
1420    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1421        (unused parameter) and in the pcre_printint() function (omitted "default"
1422        switch label when the default is to do nothing).
1423    
1424    15. Added some code to make it possible, when PCRE is compiled as a C++
1425        library, to replace subject pointers for pcre_exec() with a smart pointer
1426        class, thus making it possible to process discontinuous strings.
1427    
1428    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1429        much the same function. They were added by different people who were trying
1430        to make PCRE easy to compile on non-Unix systems. It has been suggested
1431        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1432        for compiling on Windows systems. I have therefore replaced it with
1433        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1434        defaults to "extern" for C or "extern C" for C++, which works fine on
1435        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1436        SCOPE with something explicit in config.h. In addition:
1437    
1438        (a) pcreposix.h still had just "extern" instead of either of these macros;
1439            I have replaced it with PCRE_DATA_SCOPE.
1440    
1441        (b) Functions such as _pcre_xclass(), which are internal to the library,
1442            but external in the C sense, all had PCRE_EXPORT in their definitions.
1443            This is apparently wrong for the Windows case, so I have removed it.
1444            (It makes no difference on Unix-like systems.)
1445    
1446    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1447        of recursive calls to match(). This is different to MATCH_LIMIT because
1448        that limits the total number of calls to match(), not all of which increase
1449        the depth of recursion. Limiting the recursion depth limits the amount of
1450        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1451        when PCRE is compiled, and changed at run time. A patch from Google adds
1452        this functionality to the C++ interface.
1453    
1454    18. Changes to the handling of Unicode character properties:
1455    
1456        (a) Updated the table to Unicode 4.1.0.
1457    
1458        (b) Recognize characters that are not in the table as "Cn" (undefined).
1459    
1460        (c) I revised the way the table is implemented to a much improved format
1461            which includes recognition of ranges. It now supports the ranges that
1462            are defined in UnicodeData.txt, and it also amalgamates other
1463            characters into ranges. This has reduced the number of entries in the
1464            table from around 16,000 to around 3,000, thus reducing its size
1465            considerably. I realized I did not need to use a tree structure after
1466            all - a binary chop search is just as efficient. Having reduced the
1467            number of entries, I extended their size from 6 bytes to 8 bytes to
1468            allow for more data.
1469    
1470        (d) Added support for Unicode script names via properties such as \p{Han}.
1471    
1472    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1473        matching that character.
1474    
1475    20. When matching a repeated Unicode property with a minimum greater than zero,
1476        (for example \pL{2,}), PCRE could look past the end of the subject if it
1477        reached it while seeking the minimum number of characters. This could
1478        happen only if some of the characters were more than one byte long, because
1479        there is a check for at least the minimum number of bytes.
1480    
1481    21. Refactored the implementation of \p and \P so as to be more general, to
1482        allow for more different types of property in future. This has changed the
1483        compiled form incompatibly. Anybody with saved compiled patterns that use
1484        \p or \P will have to recompile them.
1485    
1486    22. Added "Any" and "L&" to the supported property types.
1487    
1488    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1489        but give a compile time error if the value is greater than 0xff.
1490    
1491    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1492        accidentally not being installed or uninstalled.
1493    
1494    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1495        made were to insert the current release number. This seemed silly, because
1496        it made things harder for people building PCRE on systems that don't run
1497        "configure". I have turned pcre.h into a distributed file, no longer built
1498        by "configure", with the version identification directly included. There is
1499        no longer a pcre.h.in file.
1500    
1501        However, this change necessitated a change to the pcre-config script as
1502        well. It is built from pcre-config.in, and one of the substitutions was the
1503        release number. I have updated configure.ac so that ./configure now finds
1504        the release number by grepping pcre.h.
1505    
1506    26. Added the ability to run the tests under valgrind.
1507    
1508    
1509    Version 6.4 05-Sep-05
1510    ---------------------
1511    
1512     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1513        "--" to be printed when multiple files were scanned, even when none of the
1514        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1515        consider it to be a bug, and have restored the previous behaviour.
1516    
1517     2. A couple of code tidies to get rid of compiler warnings.
1518    
1519     3. The pcretest program used to cheat by referring to symbols in the library
1520        whose names begin with _pcre_. These are internal symbols that are not
1521        really supposed to be visible externally, and in some environments it is
1522        possible to suppress them. The cheating is now confined to including
1523        certain files from the library's source, which is a bit cleaner.
1524    
1525     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1526        file's purpose clearer.
1527    
1528     5. Reorganized pcre_ucp_findchar().
1529    
1530    
1531    Version 6.3 15-Aug-05
1532    ---------------------
1533    
1534     1. The file libpcre.pc.in did not have general read permission in the tarball.
1535    
1536     2. There were some problems when building without C++ support:
1537    
1538        (a) If C++ support was not built, "make install" and "make test" still
1539            tried to test it.
1540    
1541        (b) There were problems when the value of CXX was explicitly set. Some
1542            changes have been made to try to fix these, and ...
1543    
1544        (c) --disable-cpp can now be used to explicitly disable C++ support.
1545    
1546        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1547            backslash in a target when C++ was disabled. This confuses some
1548            versions of "make", apparently. Using an intermediate variable solves
1549            this. (Same for CPP_LOBJ.)
1550    
1551     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1552        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1553        necessary on certain architectures.
1554    
1555     4. Added a setting of -export-symbols-regex to the link command to remove
1556        those symbols that are exported in the C sense, but actually are local
1557        within the library, and not documented. Their names all begin with
1558        "_pcre_". This is not a perfect job, because (a) we have to except some
1559        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1560        available (and never for static libraries). I have made a note to try to
1561        find a way round (a) in the future.
1562    
1563    
1564    Version 6.2 01-Aug-05
1565    ---------------------
1566    
1567     1. There was no test for integer overflow of quantifier values. A construction
1568        such as {1111111111111111} would give undefined results. What is worse, if
1569        a minimum quantifier for a parenthesized subpattern overflowed and became
1570        negative, the calculation of the memory size went wrong. This could have
1571        led to memory overwriting.
1572    
1573     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1574    
1575     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1576        operating environments where this matters.
1577    
1578     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1579        PCRE options from within the C++ wrapper.
1580    
1581     5. Named capturing subpatterns were not being correctly counted when a pattern
1582        was compiled. This caused two problems: (a) If there were more than 100
1583        such subpatterns, the calculation of the memory needed for the whole
1584        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1585        back references of the form \12, where the number was greater than 9, were
1586        not recognized as back references, even though there were sufficient
1587        previous subpatterns.
1588    
1589     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1590        versions of gcc, e.g. 2.95.4.
1591    
1592    
1593    Version 6.1 21-Jun-05
1594    ---------------------
1595    
1596     1. There was one reference to the variable "posix" in pcretest.c that was not
1597        surrounded by "#if !defined NOPOSIX".
1598    
1599     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1600        the cross-check on the old pcre_info() function, for the benefit of the
1601        cut-down version of PCRE that is currently imported into Exim.
1602    
1603     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1604        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1605        patterns that start (?i) but I don't think that matters. The use of (?i) is
1606        just an example; this all applies to the other options as well.
1607    
1608     4. Since libtool seems to echo the compile commands it is issuing, the output
1609        from "make" can be reduced a bit by putting "@" in front of each libtool
1610        compile command.
1611    
1612     5. Patch from the folks at Google for configure.in to be a bit more thorough
1613        in checking for a suitable C++ installation before trying to compile the
1614        C++ stuff. This should fix a reported problem when a compiler was present,
1615        but no suitable headers.
1616    
1617     6. The man pages all had just "PCRE" as their title. I have changed them to
1618        be the relevant file name. I have also arranged that these names are
1619        retained in the file doc/pcre.txt, which is a concatenation in text format
1620        of all the man pages except the little individual ones for each function.
1621    
1622     7. The NON-UNIX-USE file had not been updated for the different set of source
1623        files that come with release 6. I also added a few comments about the C++
1624        wrapper.
1625    
1626    
1627  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
1628  ---------------------  ---------------------
1629    

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