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revision 79 by nigel, Sat Feb 24 21:40:52 2007 UTC revision 423 by ph10, Sat Aug 15 18:17:31 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.00 ??-???-??
5    ----------------------
6    
7    1.  The table for translating pcre_compile() error codes into POSIX error codes
8        was out-of-date, and there was no check on the pcre_compile() error code
9        being within the table. This could lead to an OK return being given in
10        error.
11    
12    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
13        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
14        in a Windows environment.
15    
16    3.  The pcregrep --count option prints the count for each file even when it is
17        zero, as does GNU grep. However, pcregrep was also printing all files when
18        --files-with-matches was added. Now, when both options are given, it prints
19        counts only for those files that have at least one match. (GNU grep just
20        prints the file name in this circumstance, but including the count seems
21        more useful - otherwise, why use --count?) Also ensured that the
22        combination -clh just lists non-zero counts, with no names.
23    
24    4.  The long form of the pcregrep -F option was incorrectly implemented as
25        --fixed_strings instead of --fixed-strings. This is an incompatible change,
26        but it seems right to fix it, and I didn't think it was worth preserving
27        the old behaviour.
28    
29    5.  The command line items --regex=pattern and --regexp=pattern were not
30        recognized by pcregrep, which required --regex pattern or --regexp pattern
31        (with a space rather than an '='). The man page documented the '=' forms,
32        which are compatible with GNU grep; these now work.
33    
34    6.  No libpcreposix.pc file was created for pkg-config; there was just
35        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
36    
37    
38    Version 7.9 11-Apr-09
39    ---------------------
40    
41    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
42        (pcretest), all targets were linked against these libraries. This included
43        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
44        libraries. This caused unwanted dependencies to be created. This problem
45        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
46        pcretest is linked with readline.
47    
48    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
49        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
50        moved outside it again, because FALSE and TRUE are already defined in AIX,
51        but BOOL is not.
52    
53    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
54        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
55    
56    4.  The pcregrep documentation said spaces were inserted as well as colons (or
57        hyphens) following file names and line numbers when outputting matching
58        lines. This is not true; no spaces are inserted. I have also clarified the
59        wording for the --colour (or --color) option.
60    
61    5.  In pcregrep, when --colour was used with -o, the list of matching strings
62        was not coloured; this is different to GNU grep, so I have changed it to be
63        the same.
64    
65    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
66        each matching line was coloured. Now it goes on to look for further matches
67        of any of the test patterns, which is the same behaviour as GNU grep.
68    
69    7.  A pattern that could match an empty string could cause pcregrep to loop; it
70        doesn't make sense to accept an empty string match in pcregrep, so I have
71        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
72        seems to be how GNU grep behaves.
73    
74    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
75        start or after a newline", because the conditional assertion was not being
76        correctly handled. The rule now is that both the assertion and what follows
77        in the first alternative must satisfy the test.
78    
79    9.  If auto-callout was enabled in a pattern with a conditional group whose
80        condition was an assertion, PCRE could crash during matching, both with
81        pcre_exec() and pcre_dfa_exec().
82    
83    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
84        used for matching.
85    
86    11. Unicode property support in character classes was not working for
87        characters (bytes) greater than 127 when not in UTF-8 mode.
88    
89    12. Added the -M command line option to pcretest.
90    
91    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
92    
93    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
94    
95    16. Added comments and documentation about mis-use of no_arg in the C++
96        wrapper.
97    
98    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
99        from Martin Jerabek that uses macro names for all relevant character and
100        string constants.
101    
102    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
103        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
104        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
105        these, but not everybody uses configure.
106    
107    19. A conditional group that had only one branch was not being correctly
108        recognized as an item that could match an empty string. This meant that an
109        enclosing group might also not be so recognized, causing infinite looping
110        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
111        with the subject "ab", where knowledge that the repeated group can match
112        nothing is needed in order to break the loop.
113    
114    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
115        exec(), but without supplying a callout function, matching went wrong.
116    
117    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
118        leak if the size of the offset vector was greater than 30. When the vector
119        is smaller, the saved offsets during recursion go onto a local stack
120        vector, but for larger vectors malloc() is used. It was failing to free
121        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
122        error, in fact).
123    
124    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
125        heapframe that is used only when UTF-8 support is enabled. This caused no
126        problem, but was untidy.
127    
128    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
129        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
130        included within another project.
131    
132    24. Steven Van Ingelgem's patches to add more options to the CMake support,
133        slightly modified by me:
134    
135          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
136              not building pcregrep.
137    
138          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
139              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
140    
141    25. Forward references, both numeric and by name, in patterns that made use of
142        duplicate group numbers, could behave incorrectly or give incorrect errors,
143        because when scanning forward to find the reference group, PCRE was not
144        taking into account the duplicate group numbers. A pattern such as
145        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
146    
147    26. Changed a few more instances of "const unsigned char *" to USPTR, making
148        the feature of a custom pointer more persuasive (as requested by a user).
149    
150    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
151        pcretest.c, inside #ifndefs, because it seems they are sometimes already
152        pre-defined.
153    
154    28. Added support for (*UTF8) at the start of a pattern.
155    
156    29. Arrange for flags added by the "release type" setting in CMake to be shown
157        in the configuration summary.
158    
159    
160    Version 7.8 05-Sep-08
161    ---------------------
162    
163    1.  Replaced UCP searching code with optimized version as implemented for Ad
164        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
165        stage table and inline lookup instead of a function, giving speed ups of 2
166        to 5 times on some simple patterns that I tested. Permission was given to
167        distribute the MultiStage2.py script that generates the tables (it's not in
168        the tarball, but is in the Subversion repository).
169    
170    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
171        scripts.
172    
173    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
174        a group with a zero qualifier. The result of the study could be incorrect,
175        or the function might crash, depending on the pattern.
176    
177    4.  Caseless matching was not working for non-ASCII characters in back
178        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
179        It now works when Unicode Property Support is available.
180    
181    5.  In pcretest, an escape such as \x{de} in the data was always generating
182        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
183        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
184        truncation.
185    
186    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
187    
188    7.  Added two (int) casts to pcregrep when printing the difference of two
189        pointers, in case they are 64-bit values.
190    
191    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
192        test 2 if it fails.
193    
194    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
195        and a #define of that name to empty if it is not externally set. This is to
196        allow users of MSVC to set it if necessary.
197    
198    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
199        the convenience functions in the pcre_get.c source file.
200    
201    11. An option change at the start of a pattern that had top-level alternatives
202        could cause overwriting and/or a crash. This command provoked a crash in
203        some environments:
204    
205          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
206    
207        This potential security problem was recorded as CVE-2008-2371.
208    
209    12. For a pattern where the match had to start at the beginning or immediately
210        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
211        pcre_dfa_exec() could read past the end of the passed subject if there was
212        no match. To help with detecting such bugs (e.g. with valgrind), I modified
213        pcretest so that it places the subject at the end of its malloc-ed buffer.
214    
215    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
216        exec() might read past the end of the data buffer in UTF-8 mode.
217    
218    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
219        the data contained the byte 0x85 as part of a UTF-8 character within its
220        first line. This applied both to normal and DFA matching.
221    
222    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
223        /^[^d]*?$/8 failed to match "abc".
224    
225    16. Added a missing copyright notice to pcrecpp_internal.h.
226    
227    17. Make it more clear in the documentation that values returned from
228        pcre_exec() in ovector are byte offsets, not character counts.
229    
230    18. Tidied a few places to stop certain compilers from issuing warnings.
231    
232    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
233        supplied by Stefan Weber. I made a further small update for 7.8 because
234        there is a change of source arrangements: the pcre_searchfuncs.c module is
235        replaced by pcre_ucd.c.
236    
237    
238    Version 7.7 07-May-08
239    ---------------------
240    
241    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
242        a string to a long long, pretend we don't even have a long long." This is
243        done by checking for the strtoq, strtoll, and _strtoi64 functions.
244    
245    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
246        pre-7.6 versions, which defined a global no_arg variable instead of putting
247        it in the RE class. (See also #8 below.)
248    
249    3.  Remove a line of dead code, identified by coverity and reported by Nuno
250        Lopes.
251    
252    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
253    
254        (1) The include/exclude patterns were being applied to the whole pathnames
255            of files, instead of just to the final components.
256    
257        (2) If there was more than one level of directory, the subdirectories were
258            skipped unless they satisfied the include/exclude conditions. This is
259            inconsistent with GNU grep (and could even be seen as contrary to the
260            pcregrep specification - which I improved to make it absolutely clear).
261            The action now is always to scan all levels of directory, and just
262            apply the include/exclude patterns to regular files.
263    
264    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
265        --exclude_dir in the tests to avoid scanning .svn directories.
266    
267    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
268        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
269        doesn't support NULs in patterns.
270    
271    7.  Added some missing "const"s to declarations of static tables in
272        pcre_compile.c and pcre_dfa_exec.c.
273    
274    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
275        caused by fix #2  above. (Subsequently also a second patch to fix the
276        first patch. And a third patch - this was a messy problem.)
277    
278    9.  Applied Craig's patch to remove the use of push_back().
279    
280    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
281        matching function regexec().
282    
283    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
284        which, however, unlike Perl's \g{...}, are subroutine calls, not back
285        references. PCRE supports relative numbers with this syntax (I don't think
286        Oniguruma does).
287    
288    12. Previously, a group with a zero repeat such as (...){0} was completely
289        omitted from the compiled regex. However, this means that if the group
290        was called as a subroutine from elsewhere in the pattern, things went wrong
291        (an internal error was given). Such groups are now left in the compiled
292        pattern, with a new opcode that causes them to be skipped at execution
293        time.
294    
295    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
296        to the way PCRE behaves:
297    
298        (a) A lone ] character is dis-allowed (Perl treats it as data).
299    
300        (b) A back reference to an unmatched subpattern matches an empty string
301            (Perl fails the current match path).
302    
303        (c) A data ] in a character class must be notated as \] because if the
304            first data character in a class is ], it defines an empty class. (In
305            Perl it is not possible to have an empty class.) The empty class []
306            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
307            The negative empty class [^] matches any one character, independently
308            of the DOTALL setting.
309    
310    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
311        non-existent subpattern following a character class starting with ']' and
312        containing () gave an internal compiling error instead of "reference to
313        non-existent subpattern". Fortunately, when the pattern did exist, the
314        compiled code was correct. (When scanning forwards to check for the
315        existencd of the subpattern, it was treating the data ']' as terminating
316        the class, so got the count wrong. When actually compiling, the reference
317        was subsequently set up correctly.)
318    
319    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
320        it was being rejected as not supported by pcre_dfa_exec(), even though
321        other assertions are supported. I have made pcre_dfa_exec() support
322        (*FAIL).
323    
324    16. The implementation of 13c above involved the invention of a new opcode,
325        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
326        cannot be changed at match time, I realized I could make a small
327        improvement to matching performance by compiling OP_ALLANY instead of
328        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
329        on the OP_ANY path.
330    
331    17. Compiling pcretest on Windows with readline support failed without the
332        following two fixes: (1) Make the unistd.h include conditional on
333        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
334    
335    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
336        ncurses library to be included for pcretest when ReadLine support is
337        requested, but also to allow for it to be overridden. This patch came from
338        Daniel Bergström.
339    
340    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
341        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
342        any errors with the current Unicode tables. Thanks to Peter Kankowski for
343        spotting this.
344    
345    
346    Version 7.6 28-Jan-08
347    ---------------------
348    
349    1.  A character class containing a very large number of characters with
350        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
351        overflow.
352    
353    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
354        HAVE_LONG_LONG is not defined.
355    
356    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
357        bring them up to date and include new features. This patch includes:
358    
359        - Fixed PH's badly added libz and libbz2 support.
360        - Fixed a problem with static linking.
361        - Added pcredemo. [But later removed - see 7 below.]
362        - Fixed dftables problem and added an option.
363        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
364            HAVE_LONG_LONG.
365        - Added readline support for pcretest.
366        - Added an listing of the option settings after cmake has run.
367    
368    4.  A user submitted a patch to Makefile that makes it easy to create
369        "pcre.dll" under mingw when using Configure/Make. I added stuff to
370        Makefile.am that cause it to include this special target, without
371        affecting anything else. Note that the same mingw target plus all
372        the other distribution libraries and programs are now supported
373        when configuring with CMake (see 6 below) instead of with
374        Configure/Make.
375    
376    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
377        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
378        exported in the Windows port". It has not yet been confirmed that the patch
379        solves the problem, but it does no harm.
380    
381    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
382        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
383        with CMake, and also correct the comment about stack recursion.
384    
385    7.  Remove the automatic building of pcredemo from the ./configure system and
386        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
387        of a program that users should build themselves after PCRE is installed, so
388        building it automatically is not really right. What is more, it gave
389        trouble in some build environments.
390    
391    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
392    
393    
394    Version 7.5 10-Jan-08
395    ---------------------
396    
397    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
398        values in parens when parsing an RE using the C++ wrapper."
399    
400    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
401        Characters greater than 255 were excluded from the class instead of being
402        included.
403    
404    3.  The same bug as (2) above applied to negated POSIX classes such as
405        [:^space:].
406    
407    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
408        defined or documented. It seems to have been a typo for PCRE_STATIC, so
409        I have changed it.
410    
411    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
412        first named subpattern) and a construct such as (?&a) would reference the
413        first named subpattern whose name started with "a" (in other words, the
414        length check was missing). Both these problems are fixed. "Subpattern name
415        expected" is now given for (?&) (a zero-length name), and this patch also
416        makes it give the same error for \k'' (previously it complained that that
417        was a reference to a non-existent subpattern).
418    
419    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
420        this is right because (?- can be followed by option settings as well as by
421        digits. I have, however, made the messages clearer.
422    
423    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
424        than the number used in the conditional) now cause a compile-time error.
425        This is actually not compatible with Perl, which accepts such patterns, but
426        treats the conditional as always being FALSE (as PCRE used to), but it
427        seems to me that giving a diagnostic is better.
428    
429    8.  Change "alphameric" to the more common word "alphanumeric" in comments
430        and messages.
431    
432    9.  Fix two occurrences of "backslash" in comments that should have been
433        "backspace".
434    
435    10. Remove two redundant lines of code that can never be obeyed (their function
436        was moved elsewhere).
437    
438    11. The program that makes PCRE's Unicode character property table had a bug
439        which caused it to generate incorrect table entries for sequences of
440        characters that have the same character type, but are in different scripts.
441        It amalgamated them into a single range, with the script of the first of
442        them. In other words, some characters were in the wrong script. There were
443        thirteen such cases, affecting characters in the following ranges:
444    
445          U+002b0 - U+002c1
446          U+0060c - U+0060d
447          U+0061e - U+00612
448          U+0064b - U+0065e
449          U+0074d - U+0076d
450          U+01800 - U+01805
451          U+01d00 - U+01d77
452          U+01d9b - U+01dbf
453          U+0200b - U+0200f
454          U+030fc - U+030fe
455          U+03260 - U+0327f
456          U+0fb46 - U+0fbb1
457          U+10450 - U+1049d
458    
459    12. The -o option (show only the matching part of a line) for pcregrep was not
460        compatible with GNU grep in that, if there was more than one match in a
461        line, it showed only the first of them. It now behaves in the same way as
462        GNU grep.
463    
464    13. If the -o and -v options were combined for pcregrep, it printed a blank
465        line for every non-matching line. GNU grep prints nothing, and pcregrep now
466        does the same. The return code can be used to tell if there were any
467        non-matching lines.
468    
469    14. Added --file-offsets and --line-offsets to pcregrep.
470    
471    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
472        infinitely looping recursion. The bug was that positive lookaheads were not
473        being skipped when checking for a possible empty match (negative lookaheads
474        and both kinds of lookbehind were skipped).
475    
476    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
477        inclusion of <windows.h> to before rather than after the definition of
478        INVALID_FILE_ATTRIBUTES (patch from David Byron).
479    
480    17. Specifying a possessive quantifier with a specific limit for a Unicode
481        character property caused pcre_compile() to compile bad code, which led at
482        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
483        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
484        caused the error; without that there was no problem.
485    
486    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
487    
488    19. Added --enable-pcretest-libreadline.
489    
490    20. In pcrecpp.cc, the variable 'count' was incremented twice in
491        RE::GlobalReplace(). As a result, the number of replacements returned was
492        double what it should be. I removed one of the increments, but Craig sent a
493        later patch that removed the other one (the right fix) and added unit tests
494        that check the return values (which was not done before).
495    
496    21. Several CMake things:
497    
498        (1) Arranged that, when cmake is used on Unix, the libraries end up with
499            the names libpcre and libpcreposix, not just pcre and pcreposix.
500    
501        (2) The above change means that pcretest and pcregrep are now correctly
502            linked with the newly-built libraries, not previously installed ones.
503    
504        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
505    
506    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
507        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
508        UTF-8 newline character). The key issue is that the pattern starts .*;
509        this means that the match must be either at the beginning, or after a
510        newline. The bug was in the code for advancing after a failed match and
511        checking that the new position followed a newline. It was not taking
512        account of UTF-8 characters correctly.
513    
514    23. PCRE was behaving differently from Perl in the way it recognized POSIX
515        character classes. PCRE was not treating the sequence [:...:] as a
516        character class unless the ... were all letters. Perl, however, seems to
517        allow any characters between [: and :], though of course it rejects as
518        unknown any "names" that contain non-letters, because all the known class
519        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
520        for example, whereas PCRE did not - it did not recognize a POSIX character
521        class. This seemed a bit dangerous, so the code has been changed to be
522        closer to Perl. The behaviour is not identical to Perl, because PCRE will
523        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
524        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
525        Perl does, and where it didn't before.
526    
527    24. Rewrite so as to remove the single use of %n from pcregrep because in some
528        Windows environments %n is disabled by default.
529    
530    
531    Version 7.4 21-Sep-07
532    ---------------------
533    
534    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
535        means that a class such as [\s] counted as "explicit reference to CR or
536        LF". That isn't really right - the whole point of the change was to try to
537        help when there was an actual mention of one of the two characters. So now
538        the change happens only if \r or \n (or a literal CR or LF) character is
539        encountered.
540    
541    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
542        of both had grown to the point where there were only 3 bits left.
543        Fortunately, there was spare space in the data structure, and so I have
544        moved the internal flags into a new 16-bit field to free up more option
545        bits.
546    
547    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
548        but did not set the internal JCHANGED flag - either of these is enough to
549        control the way the "get" function works - but the PCRE_INFO_JCHANGED
550        facility is supposed to tell if (?J) was ever used, so now (?J) at the
551        start sets both bits.
552    
553    4.  Added options (at build time, compile time, exec time) to change \R from
554        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
555    
556    5.  doc/pcresyntax.html was missing from the distribution.
557    
558    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
559        compatibility, even though it is no longer used.
560    
561    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
562        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
563        windows.h file is present (where different names are used). [This was
564        reversed later after testing - see 16 below.]
565    
566    8.  Changed all #include <config.h> to #include "config.h". There were also
567        some further <pcre.h> cases that I changed to "pcre.h".
568    
569    9.  When pcregrep was used with the --colour option, it missed the line ending
570        sequence off the lines that it output.
571    
572    10. It was pointed out to me that arrays of string pointers cause lots of
573        relocations when a shared library is dynamically loaded. A technique of
574        using a single long string with a table of offsets can drastically reduce
575        these. I have refactored PCRE in four places to do this. The result is
576        dramatic:
577    
578          Originally:                          290
579          After changing UCP table:            187
580          After changing error message table:   43
581          After changing table of "verbs"       36
582          After changing table of Posix names   22
583    
584        Thanks to the folks working on Gregex for glib for this insight.
585    
586    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
587        unicode-properties was also set.
588    
589    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
590    
591    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
592        checked only for CRLF.
593    
594    14. Added casts to pcretest.c to avoid compiler warnings.
595    
596    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
597    
598    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
599        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
600        entirely. This removes changes made in 7 above.
601    
602    17. The CMake files have been updated, and there is now more information about
603        building with CMake in the NON-UNIX-USE document.
604    
605    
606    Version 7.3 28-Aug-07
607    ---------------------
608    
609     1. In the rejigging of the build system that eventually resulted in 7.1, the
610        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
611        brackets there is not right, since it causes compilers to look for an
612        installed pcre.h, not the version that is in the source that is being
613        compiled (which of course may be different). I have changed it back to:
614    
615          #include "pcre.h"
616    
617        I have a vague recollection that the change was concerned with compiling in
618        different directories, but in the new build system, that is taken care of
619        by the VPATH setting the Makefile.
620    
621     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
622        when the subject happened to end in the byte 0x85 (e.g. if the last
623        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
624        characters but of course it shouldn't be taken as a newline when it is part
625        of another character. The bug was that, for an unlimited repeat of . in
626        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
627        characters when looking for a newline.
628    
629     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
630    
631     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
632        in debug output.
633    
634     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
635        long printing in the pcrecpp unittest when running under MinGW.
636    
637     6. ESC_K was left out of the EBCDIC table.
638    
639     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
640        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
641        limit also applies to "virtual nesting" when a pattern is recursive, and in
642        this case 1000 isn't so big. I have been able to remove this limit at the
643        expense of backing off one optimization in certain circumstances. Normally,
644        when pcre_exec() would call its internal match() function recursively and
645        immediately return the result unconditionally, it uses a "tail recursion"
646        feature to save stack. However, when a subpattern that can match an empty
647        string has an unlimited repetition quantifier, it no longer makes this
648        optimization. That gives it a stack frame in which to save the data for
649        checking that an empty string has been matched. Previously this was taken
650        from the 1000-entry workspace that had been reserved. So now there is no
651        explicit limit, but more stack is used.
652    
653     8. Applied Daniel's patches to solve problems with the import/export magic
654        syntax that is required for Windows, and which was going wrong for the
655        pcreposix and pcrecpp parts of the library. These were overlooked when this
656        problem was solved for the main library.
657    
658     9. There were some crude static tests to avoid integer overflow when computing
659        the size of patterns that contain repeated groups with explicit upper
660        limits. As the maximum quantifier is 65535, the maximum group length was
661        set at 30,000 so that the product of these two numbers did not overflow a
662        32-bit integer. However, it turns out that people want to use groups that
663        are longer than 30,000 bytes (though not repeat them that many times).
664        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
665        made it possible to implement the integer overflow checks in a much more
666        dynamic way, which I have now done. The artificial limitation on group
667        length has been removed - we now have only the limit on the total length of
668        the compiled pattern, which depends on the LINK_SIZE setting.
669    
670    10. Fixed a bug in the documentation for get/copy named substring when
671        duplicate names are permitted. If none of the named substrings are set, the
672        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
673        empty string.
674    
675    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
676        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
677        because the ] is interpreted as the first data character and the
678        terminating ] is not found. PCRE has been made compatible with Perl in this
679        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
680        cause memory overwriting.
681    
682    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
683        string has been matched (to stop an infinite loop). It was not recognizing
684        a conditional subpattern that could match an empty string if that
685        subpattern was within another subpattern. For example, it looped when
686        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
687        condition was not nested. This bug has been fixed.
688    
689    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
690        past the start of the subject in the presence of bytes with the top bit
691        set, for example "\x8aBCD".
692    
693    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
694        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
695    
696    14. Optimized (?!) to (*FAIL).
697    
698    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
699        This restricts code points to be within the range 0 to 0x10FFFF, excluding
700        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
701        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
702        does: it's just the validity check that is more restrictive.
703    
704    16. Inserted checks for integer overflows during escape sequence (backslash)
705        processing, and also fixed erroneous offset values for syntax errors during
706        backslash processing.
707    
708    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
709        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
710    
711    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
712        caused an overrun.
713    
714    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
715        something other than just ASCII characters) inside a group that had an
716        unlimited repeat caused a loop at compile time (while checking to see
717        whether the group could match an empty string).
718    
719    20. Debugging a pattern containing \p or \P could cause a crash. For example,
720        [\P{Any}] did so. (Error in the code for printing property names.)
721    
722    21. An orphan \E inside a character class could cause a crash.
723    
724    22. A repeated capturing bracket such as (A)? could cause a wild memory
725        reference during compilation.
726    
727    23. There are several functions in pcre_compile() that scan along a compiled
728        expression for various reasons (e.g. to see if it's fixed length for look
729        behind). There were bugs in these functions when a repeated \p or \P was
730        present in the pattern. These operators have additional parameters compared
731        with \d, etc, and these were not being taken into account when moving along
732        the compiled data. Specifically:
733    
734        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
735            length.
736    
737        (b) An item such as \pL+ within a repeated group could cause crashes or
738            loops.
739    
740        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
741            "reference to non-existent subpattern" error.
742    
743        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
744    
745    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
746        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
747    
748    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
749    
750    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
751        character were causing crashes (broken optimization).
752    
753    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
754        \p or \P) caused a compile-time loop.
755    
756    28. More problems have arisen in unanchored patterns when CRLF is a valid line
757        break. For example, the unstudied pattern [\r\n]A does not match the string
758        "\r\nA" because change 7.0/46 below moves the current point on by two
759        characters after failing to match at the start. However, the pattern \nA
760        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
761        the same is true. There doesn't seem any very clean way out of this, but
762        what I have chosen to do makes the common cases work: PCRE now takes note
763        of whether there can be an explicit match for \r or \n anywhere in the
764        pattern, and if so, 7.0/46 no longer applies. As part of this change,
765        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
766        pattern has explicit CR or LF references.
767    
768    29. Added (*CR) etc for changing newline setting at start of pattern.
769    
770    
771    Version 7.2 19-Jun-07
772    ---------------------
773    
774     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
775        which is apparently normally available under Windows.
776    
777     2. Re-jig the pcregrep tests with different newline settings in an attempt
778        to make them independent of the local environment's newline setting.
779    
780     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
781    
782     4. Some of the "internals" tests were previously cut out when the link size
783        was not 2, because the output contained actual offsets. The recent new
784        "Z" feature of pcretest means that these can be cut out, making the tests
785        usable with all link sizes.
786    
787     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
788        stack recursion. This gives a massive performance boost under BSD, but just
789        a small improvement under Linux. However, it saves one field in the frame
790        in all cases.
791    
792     6. Added more features from the forthcoming Perl 5.10:
793    
794        (a) (?-n) (where n is a string of digits) is a relative subroutine or
795            recursion call. It refers to the nth most recently opened parentheses.
796    
797        (b) (?+n) is also a relative subroutine call; it refers to the nth next
798            to be opened parentheses.
799    
800        (c) Conditions that refer to capturing parentheses can be specified
801            relatively, for example, (?(-2)... or (?(+3)...
802    
803        (d) \K resets the start of the current match so that everything before
804            is not part of it.
805    
806        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
807    
808        (f) \g{name} is another synonym - part of Perl 5.10's unification of
809            reference syntax.
810    
811        (g) (?| introduces a group in which the numbering of parentheses in each
812            alternative starts with the same number.
813    
814        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
815    
816     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
817        PCRE_INFO_JCHANGED.
818    
819     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
820        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
821        for detecting groups that can match an empty string.
822    
823     9. A pattern with a very large number of alternatives (more than several
824        hundred) was running out of internal workspace during the pre-compile
825        phase, where pcre_compile() figures out how much memory will be needed. A
826        bit of new cunning has reduced the workspace needed for groups with
827        alternatives. The 1000-alternative test pattern now uses 12 bytes of
828        workspace instead of running out of the 4096 that are available.
829    
830    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
831    
832    11. Applied patch from Google to remove an optimization that didn't quite work.
833        The report of the bug said:
834    
835          pcrecpp::RE("a*").FullMatch("aaa") matches, while
836          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
837          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
838    
839    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
840        it matched the wrong number of bytes.
841    
842    
843    Version 7.1 24-Apr-07
844    ---------------------
845    
846     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
847        that is more "standard", making use of automake and other Autotools. There
848        is some re-arrangement of the files and adjustment of comments consequent
849        on this.
850    
851     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
852        for recursive directory scanning broke on some systems because the files
853        are not scanned in any specific order and on different systems the order
854        was different. A call to "sort" has been inserted into RunGrepTest for the
855        approprate test as a short-term fix. In the longer term there may be an
856        alternative.
857    
858     3. I had an email from Eric Raymond about problems translating some of PCRE's
859        man pages to HTML (despite the fact that I distribute HTML pages, some
860        people do their own conversions for various reasons). The problems
861        concerned the use of low-level troff macros .br and .in. I have therefore
862        removed all such uses from the man pages (some were redundant, some could
863        be replaced by .nf/.fi pairs). The 132html script that I use to generate
864        HTML has been updated to handle .nf/.fi and to complain if it encounters
865        .br or .in.
866    
867     4. Updated comments in configure.ac that get placed in config.h.in and also
868        arranged for config.h to be included in the distribution, with the name
869        config.h.generic, for the benefit of those who have to compile without
870        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
871    
872     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
873        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
874        makevp.bat for the current PCRE, using the additional files
875        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
876    
877     6. A Windows user reported a minor discrepancy with test 2, which turned out
878        to be caused by a trailing space on an input line that had got lost in his
879        copy. The trailing space was an accident, so I've just removed it.
880    
881     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
882        that is needed.
883    
884     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
885        as "const" (a) because they are and (b) because it helps the PHP
886        maintainers who have recently made a script to detect big data structures
887        in the php code that should be moved to the .rodata section. I remembered
888        to update Builducptable as well, so it won't revert if ucptable.h is ever
889        re-created.
890    
891     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
892        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
893        order to be able to cut out the UTF-8 tables in the latter when UTF-8
894        support is not required. This saves 1.5-2K of code, which is important in
895        some applications.
896    
897        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
898        so as not to refer to the tables, even though these functions will never be
899        called when UTF-8 support is disabled. Otherwise there are problems with a
900        shared library.
901    
902    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
903    
904        (a) It was defining its arguments as char * instead of void *.
905    
906        (b) It was assuming that all moves were upwards in memory; this was true
907            a long time ago when I wrote it, but is no longer the case.
908    
909        The emulated memove() is provided for those environments that have neither
910        memmove() nor bcopy(). I didn't think anyone used it these days, but that
911        is clearly not the case, as these two bugs were recently reported.
912    
913    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
914        and Detrail to create the HTML documentation, the .txt form of the man
915        pages, and it removes trailing spaces from listed files. It also creates
916        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
917        case, it wraps all the #defines with #ifndefs. This script should be run
918        before "make dist".
919    
920    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
921        with Unicode property support.
922    
923        (a) For a maximizing quantifier, if the two different cases of the
924            character were of different lengths in their UTF-8 codings (there are
925            some cases like this - I found 11), and the matching function had to
926            back up over a mixture of the two cases, it incorrectly assumed they
927            were both the same length.
928    
929        (b) When PCRE was configured to use the heap rather than the stack for
930            recursion during matching, it was not correctly preserving the data for
931            the other case of a UTF-8 character when checking ahead for a match
932            while processing a minimizing repeat. If the check also involved
933            matching a wide character, but failed, corruption could cause an
934            erroneous result when trying to check for a repeat of the original
935            character.
936    
937    13. Some tidying changes to the testing mechanism:
938    
939        (a) The RunTest script now detects the internal link size and whether there
940            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
941            values substituted by "configure". (The RunGrepTest script already did
942            this for UTF-8.) The configure.ac script no longer substitutes the
943            relevant variables.
944    
945        (b) The debugging options /B and /D in pcretest show the compiled bytecode
946            with length and offset values. This means that the output is different
947            for different internal link sizes. Test 2 is skipped for link sizes
948            other than 2 because of this, bypassing the problem. Unfortunately,
949            there was also a test in test 3 (the locale tests) that used /B and
950            failed for link sizes other than 2. Rather than cut the whole test out,
951            I have added a new /Z option to pcretest that replaces the length and
952            offset values with spaces. This is now used to make test 3 independent
953            of link size. (Test 2 will be tidied up later.)
954    
955    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
956        segmentation fault instead of returning the appropriate error message.
957    
958    15. In multiline mode when the newline sequence was set to "any", the pattern
959        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
960        This doesn't seem right; it now treats the CRLF combination as the line
961        ending, and so does not match in that case. It's only a pattern such as ^$
962        that would hit this one: something like ^ABC$ would have failed after \r
963        and then tried again after \r\n.
964    
965    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
966        in an attempt to make files that differ only in their line terminators
967        compare equal. This works on Linux.
968    
969    17. Under certain error circumstances pcregrep might try to free random memory
970        as it exited. This is now fixed, thanks to valgrind.
971    
972    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
973        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
974        was because its rules for how to advance for /g after matching an empty
975        string at the end of a line did not allow for this case. They now check for
976        it specially.
977    
978    20. pcretest is supposed to handle patterns and data of any length, by
979        extending its buffers when necessary. It was getting this wrong when the
980        buffer for a data line had to be extended.
981    
982    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
983        CRLF as a newline sequence.
984    
985    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
986        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
987        I have nevertheless tidied it up.
988    
989    23. Added some casts to kill warnings from HP-UX ia64 compiler.
990    
991    24. Added a man page for pcre-config.
992    
993    
994    Version 7.0 19-Dec-06
995    ---------------------
996    
997     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
998        moving to gcc 4.1.1.
999    
1000     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
1001        sys/time.h, which is documented as needed for this function. It doesn't
1002        seem to matter on Linux, but it showed up on some releases of OS X.
1003    
1004     3. It seems that there are systems where bytes whose values are greater than
1005        127 match isprint() in the "C" locale. The "C" locale should be the
1006        default when a C program starts up. In most systems, only ASCII printing
1007        characters match isprint(). This difference caused the output from pcretest
1008        to vary, making some of the tests fail. I have changed pcretest so that:
1009    
1010        (a) When it is outputting text in the compiled version of a pattern, bytes
1011            other than 32-126 are always shown as hex escapes.
1012    
1013        (b) When it is outputting text that is a matched part of a subject string,
1014            it does the same, unless a different locale has been set for the match
1015            (using the /L modifier). In this case, it uses isprint() to decide.
1016    
1017     4. Fixed a major bug that caused incorrect computation of the amount of memory
1018        required for a compiled pattern when options that changed within the
1019        pattern affected the logic of the preliminary scan that determines the
1020        length. The relevant options are -x, and -i in UTF-8 mode. The result was
1021        that the computed length was too small. The symptoms of this bug were
1022        either the PCRE error "internal error: code overflow" from pcre_compile(),
1023        or a glibc crash with a message such as "pcretest: free(): invalid next
1024        size (fast)". Examples of patterns that provoked this bug (shown in
1025        pcretest format) are:
1026    
1027          /(?-x: )/x
1028          /(?x)(?-x: \s*#\s*)/
1029          /((?i)[\x{c0}])/8
1030          /(?i:[\x{c0}])/8
1031    
1032        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
1033        is now done differently.
1034    
1035     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
1036        wrapper classes; (b) implement a new function in the C++ scanner that is
1037        more efficient than the old way of doing things because it avoids levels of
1038        recursion in the regex matching; (c) add a paragraph to the documentation
1039        for the FullMatch() function.
1040    
1041     6. The escape sequence \n was being treated as whatever was defined as
1042        "newline". Not only was this contrary to the documentation, which states
1043        that \n is character 10 (hex 0A), but it also went horribly wrong when
1044        "newline" was defined as CRLF. This has been fixed.
1045    
1046     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
1047        was being set to -1 for the "end of line" case (supposedly a value that no
1048        character can have). Though this value is never used (the check for end of
1049        line is "zero bytes in current character"), it caused compiler complaints.
1050        I've changed it to 0xffffffff.
1051    
1052     8. In pcre_version.c, the version string was being built by a sequence of
1053        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
1054        string (as it is for production releases) called a macro with an empty
1055        argument. The C standard says the result of this is undefined. The gcc
1056        compiler treats it as an empty string (which was what was wanted) but it is
1057        reported that Visual C gives an error. The source has been hacked around to
1058        avoid this problem.
1059    
1060     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
1061        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
1062        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
1063        of them did).
1064    
1065    10. Originally, pcretest opened its input and output without "b"; then I was
1066        told that "b" was needed in some environments, so it was added for release
1067        5.0 to both the input and output. (It makes no difference on Unix-like
1068        systems.) Later I was told that it is wrong for the input on Windows. I've
1069        now abstracted the modes into two macros, to make it easier to fiddle with
1070        them, and removed "b" from the input mode under Windows.
1071    
1072    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
1073    
1074    12. Added -help and --help to pcretest as an official way of being reminded
1075        of the options.
1076    
1077    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
1078        and pcrecpp.cc because they annoy compilers at high warning levels.
1079    
1080    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
1081    
1082    15. Fixed an occurrence of == in configure.ac that should have been = (shell
1083        scripts are not C programs :-) and which was not noticed because it works
1084        on Linux.
1085    
1086    16. pcretest is supposed to handle any length of pattern and data line (as one
1087        line or as a continued sequence of lines) by extending its input buffer if
1088        necessary. This feature was broken for very long pattern lines, leading to
1089        a string of junk being passed to pcre_compile() if the pattern was longer
1090        than about 50K.
1091    
1092    17. I have done a major re-factoring of the way pcre_compile() computes the
1093        amount of memory needed for a compiled pattern. Previously, there was code
1094        that made a preliminary scan of the pattern in order to do this. That was
1095        OK when PCRE was new, but as the facilities have expanded, it has become
1096        harder and harder to keep it in step with the real compile phase, and there
1097        have been a number of bugs (see for example, 4 above). I have now found a
1098        cunning way of running the real compile function in a "fake" mode that
1099        enables it to compute how much memory it would need, while actually only
1100        ever using a few hundred bytes of working memory and without too many
1101        tests of the mode. This should make future maintenance and development
1102        easier. A side effect of this work is that the limit of 200 on the nesting
1103        depth of parentheses has been removed (though this was never a serious
1104        limitation, I suspect). However, there is a downside: pcre_compile() now
1105        runs more slowly than before (30% or more, depending on the pattern). I
1106        hope this isn't a big issue. There is no effect on runtime performance.
1107    
1108    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
1109        newline (only possible for the last line of a file) and it was a
1110        pattern that set a locale (followed by /Lsomething), pcretest crashed.
1111    
1112    19. Added additional timing features to pcretest. (1) The -tm option now times
1113        matching only, not compiling. (2) Both -t and -tm can be followed, as a
1114        separate command line item, by a number that specifies the number of
1115        repeats to use when timing. The default is 50000; this gives better
1116        precision, but takes uncomfortably long for very large patterns.
1117    
1118    20. Extended pcre_study() to be more clever in cases where a branch of a
1119        subpattern has no definite first character. For example, (a*|b*)[cd] would
1120        previously give no result from pcre_study(). Now it recognizes that the
1121        first character must be a, b, c, or d.
1122    
1123    21. There was an incorrect error "recursive call could loop indefinitely" if
1124        a subpattern (or the entire pattern) that was being tested for matching an
1125        empty string contained only one non-empty item after a nested subpattern.
1126        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
1127        incorrectly, because the \d was being skipped in the check.
1128    
1129    22. The pcretest program now has a new pattern option /B and a command line
1130        option -b, which is equivalent to adding /B to every pattern. This causes
1131        it to show the compiled bytecode, without the additional information that
1132        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
1133        is the same as /B/I).
1134    
1135    23. A new optimization is now able automatically to treat some sequences such
1136        as a*b as a*+b. More specifically, if something simple (such as a character
1137        or a simple class like \d) has an unlimited quantifier, and is followed by
1138        something that cannot possibly match the quantified thing, the quantifier
1139        is automatically "possessified".
1140    
1141    24. A recursive reference to a subpattern whose number was greater than 39
1142        went wrong under certain circumstances in UTF-8 mode. This bug could also
1143        have affected the operation of pcre_study().
1144    
1145    25. Realized that a little bit of performance could be had by replacing
1146        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
1147    
1148    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
1149    
1150    27. Possessive quantifiers such as a++ were previously implemented by turning
1151        them into atomic groups such as ($>a+). Now they have their own opcodes,
1152        which improves performance. This includes the automatically created ones
1153        from 23 above.
1154    
1155    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
1156        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
1157        the first matched character to be a colon. This applied both to named and
1158        numbered groups.
1159    
1160    29. The ucpinternal.h header file was missing its idempotency #ifdef.
1161    
1162    30. I was sent a "project" file called libpcre.a.dev which I understand makes
1163        building PCRE on Windows easier, so I have included it in the distribution.
1164    
1165    31. There is now a check in pcretest against a ridiculously large number being
1166        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
1167        loop, the loop is abandoned.
1168    
1169    32. Forward references to subpatterns in conditions such as (?(2)...) where
1170        subpattern 2 is defined later cause pcre_compile() to search forwards in
1171        the pattern for the relevant set of parentheses. This search went wrong
1172        when there were unescaped parentheses in a character class, parentheses
1173        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
1174    
1175    33. "Subroutine" calls and backreferences were previously restricted to
1176        referencing subpatterns earlier in the regex. This restriction has now
1177        been removed.
1178    
1179    34. Added a number of extra features that are going to be in Perl 5.10. On the
1180        whole, these are just syntactic alternatives for features that PCRE had
1181        previously implemented using the Python syntax or my own invention. The
1182        other formats are all retained for compatibility.
1183    
1184        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
1185            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
1186            also .NET compatible.
1187    
1188        (b) A recursion or subroutine call to a named group can now be defined as
1189            (?&name) as well as (?P>name).
1190    
1191        (c) A backreference to a named group can now be defined as \k<name> or
1192            \k'name' as well as (?P=name). The new forms, as well as being in Perl
1193            5.10, are also .NET compatible.
1194    
1195        (d) A conditional reference to a named group can now use the syntax
1196            (?(<name>) or (?('name') as well as (?(name).
1197    
1198        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
1199            groups (named and numbered) that are never evaluated inline, but can be
1200            called as "subroutines" from elsewhere. In effect, the DEFINE condition
1201            is always false. There may be only one alternative in such a group.
1202    
1203        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1204            as the simple (?(R). The condition is true only if the most recent
1205            recursion is that of the given number or name. It does not search out
1206            through the entire recursion stack.
1207    
1208        (g) The escape \gN or \g{N} has been added, where N is a positive or
1209            negative number, specifying an absolute or relative reference.
1210    
1211    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1212        some "unreachable code" warnings.
1213    
1214    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1215        things, this adds five new scripts.
1216    
1217    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1218        There were also incompatibilities regarding the handling of \Q..\E inside
1219        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1220        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1221    
1222    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1223        matches an empty string, and forcibly breaks the loop. There were bugs in
1224        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1225        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1226        separate and independent bugs (that affected different cases) have been
1227        fixed.
1228    
1229    39. Refactored the code to abolish the use of different opcodes for small
1230        capturing bracket numbers. This is a tidy that I avoided doing when I
1231        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1232        The new approach is not only tidier, it makes it possible to reduce the
1233        memory needed to fix the previous bug (38).
1234    
1235    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1236        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1237        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1238        mode.
1239    
1240    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1241        report.
1242    
1243    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1244        copy construction and assignment in the C++ wrapper.
1245    
1246    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1247        couple of bugs that could have given wrong results in the "--newline=crlf"
1248        case.
1249    
1250    44. Added a number of casts and did some reorganization of signed/unsigned int
1251        variables following suggestions from Dair Grant. Also renamed the variable
1252        "this" as "item" because it is a C++ keyword.
1253    
1254    45. Arranged for dftables to add
1255    
1256          #include "pcre_internal.h"
1257    
1258        to pcre_chartables.c because without it, gcc 4.x may remove the array
1259        definition from the final binary if PCRE is built into a static library and
1260        dead code stripping is activated.
1261    
1262    46. For an unanchored pattern, if a match attempt fails at the start of a
1263        newline sequence, and the newline setting is CRLF or ANY, and the next two
1264        characters are CRLF, advance by two characters instead of one.
1265    
1266    
1267    Version 6.7 04-Jul-06
1268    ---------------------
1269    
1270     1. In order to handle tests when input lines are enormously long, pcretest has
1271        been re-factored so that it automatically extends its buffers when
1272        necessary. The code is crude, but this _is_ just a test program. The
1273        default size has been increased from 32K to 50K.
1274    
1275     2. The code in pcre_study() was using the value of the re argument before
1276        testing it for NULL. (Of course, in any sensible call of the function, it
1277        won't be NULL.)
1278    
1279     3. The memmove() emulation function in pcre_internal.h, which is used on
1280        systems that lack both memmove() and bcopy() - that is, hardly ever -
1281        was missing a "static" storage class specifier.
1282    
1283     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1284        containing an extended class (one that cannot be represented by a bitmap
1285        because it contains high-valued characters or Unicode property items, e.g.
1286        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1287        pattern, but PCRE should not loop if you do not (it no longer does).
1288        [Detail: two cases were found: (a) a repeated subpattern containing an
1289        extended class; (b) a recursive reference to a subpattern that followed a
1290        previous extended class. It wasn't skipping over the extended class
1291        correctly when UTF-8 mode was not set.]
1292    
1293     5. A negated single-character class was not being recognized as fixed-length
1294        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1295        compile error "lookbehind assertion is not fixed length".
1296    
1297     6. The RunPerlTest auxiliary script was showing an unexpected difference
1298        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1299        write a Perl script that can interpret lines of an input file either as
1300        byte characters or as UTF-8, which is what "perltest" was being required to
1301        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1302        can't do is switch easily at run time between having the "use utf8;" pragma
1303        or not. In the end, I fudged it by using the RunPerlTest script to insert
1304        "use utf8;" explicitly for the UTF-8 tests.
1305    
1306     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1307        the end of the subject string, contrary to the documentation and to what
1308        Perl does. This was true of both matching functions. Now it matches only at
1309        the start of the subject and immediately after *internal* newlines.
1310    
1311     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1312        a pointer to an int instead of a pointer to an unsigned long int. This
1313        caused problems on 64-bit systems.
1314    
1315     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1316        instance of the 'standard' template library not being so standard".
1317    
1318    10. There was no check on the number of named subpatterns nor the maximum
1319        length of a subpattern name. The product of these values is used to compute
1320        the size of the memory block for a compiled pattern. By supplying a very
1321        long subpattern name and a large number of named subpatterns, the size
1322        computation could be caused to overflow. This is now prevented by limiting
1323        the length of names to 32 characters, and the number of named subpatterns
1324        to 10,000.
1325    
1326    11. Subpatterns that are repeated with specific counts have to be replicated in
1327        the compiled pattern. The size of memory for this was computed from the
1328        length of the subpattern and the repeat count. The latter is limited to
1329        65535, but there was no limit on the former, meaning that integer overflow
1330        could in principle occur. The compiled length of a repeated subpattern is
1331        now limited to 30,000 bytes in order to prevent this.
1332    
1333    12. Added the optional facility to have named substrings with the same name.
1334    
1335    13. Added the ability to use a named substring as a condition, using the
1336        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1337        are numbers (not recommended). Forward references are permitted.
1338    
1339    14. Added forward references in named backreferences (if you see what I mean).
1340    
1341    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1342        pattern could run off the end of the subject. For example, the pattern
1343        "(?s)(.{1,5})"8 did this with the subject "ab".
1344    
1345    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1346        PCRE_CASELESS was set when matching characters that were quantified with ?
1347        or *.
1348    
1349    17. A character class other than a single negated character that had a minimum
1350        but no maximum quantifier - for example [ab]{6,} - was not handled
1351        correctly by pce_dfa_exec(). It would match only one character.
1352    
1353    18. A valid (though odd) pattern that looked like a POSIX character
1354        class but used an invalid character after [ (for example [[,abc,]]) caused
1355        pcre_compile() to give the error "Failed: internal error: code overflow" or
1356        in some cases to crash with a glibc free() error. This could even happen if
1357        the pattern terminated after [[ but there just happened to be a sequence of
1358        letters, a binary zero, and a closing ] in the memory that followed.
1359    
1360    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1361        over the years. Originally (before any Unicode support), just the bottom 8
1362        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1363        output from "man perlunicode" includes this:
1364    
1365          The regular expression compiler produces polymorphic opcodes.  That
1366          is, the pattern adapts to the data and automatically switches to
1367          the Unicode character scheme when presented with Unicode data--or
1368          instead uses a traditional byte scheme when presented with byte
1369          data.
1370    
1371        Sadly, a wide octal escape does not cause a switch, and in a string with
1372        no other multibyte characters, these octal escapes are treated as before.
1373        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1374        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1375        Unicode string.
1376    
1377        I have not perpetrated such confusion in PCRE. Up till now, it took just
1378        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1379        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1380        translate to the appropriate multibyte character.
1381    
1382    29. Applied some refactoring to reduce the number of warnings from Microsoft
1383        and Borland compilers. This has included removing the fudge introduced
1384        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1385        a warning about an unused variable.
1386    
1387    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1388        characters since release 4.0, because Perl (from release 5.004) does not.
1389        [Or at least, is documented not to: some releases seem to be in conflict
1390        with the documentation.] However, when a pattern was studied with
1391        pcre_study() and all its branches started with \s, PCRE still included VT
1392        as a possible starting character. Of course, this did no harm; it just
1393        caused an unnecessary match attempt.
1394    
1395    22. Removed a now-redundant internal flag bit that recorded the fact that case
1396        dependency changed within the pattern. This was once needed for "required
1397        byte" processing, but is no longer used. This recovers a now-scarce options
1398        bit. Also moved the least significant internal flag bit to the most-
1399        significant bit of the word, which was not previously used (hangover from
1400        the days when it was an int rather than a uint) to free up another bit for
1401        the future.
1402    
1403    23. Added support for CRLF line endings as well as CR and LF. As well as the
1404        default being selectable at build time, it can now be changed at runtime
1405        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1406        specify that it is scanning data with non-default line endings.
1407    
1408    24. Changed the definition of CXXLINK to make it agree with the definition of
1409        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1410    
1411    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1412        recursions. This makes a big different to stack usage for some patterns.
1413    
1414    26. If a subpattern containing a named recursion or subroutine reference such
1415        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1416        the space required for the compiled pattern went wrong and gave too small a
1417        value. Depending on the environment, this could lead to "Failed: internal
1418        error: code overflow at offset 49" or "glibc detected double free or
1419        corruption" errors.
1420    
1421    27. Applied patches from Google (a) to support the new newline modes and (b) to
1422        advance over multibyte UTF-8 characters in GlobalReplace.
1423    
1424    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1425        difference for some implementation of PCRE in some Windows version.
1426    
1427    29. Added some extra testing facilities to pcretest:
1428    
1429        \q<number>   in a data line sets the "match limit" value
1430        \Q<number>   in a data line sets the "match recursion limt" value
1431        -S <number>  sets the stack size, where <number> is in megabytes
1432    
1433        The -S option isn't available for Windows.
1434    
1435    
1436    Version 6.6 06-Feb-06
1437    ---------------------
1438    
1439     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1440        in pcreposix.h. I have copied the definition from pcre.h.
1441    
1442     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1443        because pcre.h is no longer a built file.
1444    
1445     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1446        not normally included in the compiled code.
1447    
1448    
1449    Version 6.5 01-Feb-06
1450    ---------------------
1451    
1452     1. When using the partial match feature with pcre_dfa_exec(), it was not
1453        anchoring the second and subsequent partial matches at the new starting
1454        point. This could lead to incorrect results. For example, with the pattern
1455        /1234/, partially matching against "123" and then "a4" gave a match.
1456    
1457     2. Changes to pcregrep:
1458    
1459        (a) All non-match returns from pcre_exec() were being treated as failures
1460            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1461            error message is output. Some extra information is given for the
1462            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1463            probably the only errors that are likely to be caused by users (by
1464            specifying a regex that has nested indefinite repeats, for instance).
1465            If there are more than 20 of these errors, pcregrep is abandoned.
1466    
1467        (b) A binary zero was treated as data while matching, but terminated the
1468            output line if it was written out. This has been fixed: binary zeroes
1469            are now no different to any other data bytes.
1470    
1471        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1472            used to set a locale for matching. The --locale=xxxx long option has
1473            been added (no short equivalent) to specify a locale explicitly on the
1474            pcregrep command, overriding the environment variables.
1475    
1476        (d) When -B was used with -n, some line numbers in the output were one less
1477            than they should have been.
1478    
1479        (e) Added the -o (--only-matching) option.
1480    
1481        (f) If -A or -C was used with -c (count only), some lines of context were
1482            accidentally printed for the final match.
1483    
1484        (g) Added the -H (--with-filename) option.
1485    
1486        (h) The combination of options -rh failed to suppress file names for files
1487            that were found from directory arguments.
1488    
1489        (i) Added the -D (--devices) and -d (--directories) options.
1490    
1491        (j) Added the -F (--fixed-strings) option.
1492    
1493        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1494    
1495        (l) Added the --colo(u)r option.
1496    
1497        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1498            is not present by default.
1499    
1500     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1501        items such as (?R) or (?1), when the recursion could match a number of
1502        alternatives. If it matched one of the alternatives, but subsequently,
1503        outside the recursion, there was a failure, the code tried to back up into
1504        the recursion. However, because of the way PCRE is implemented, this is not
1505        possible, and the result was an incorrect result from the match.
1506    
1507        In order to prevent this happening, the specification of recursion has
1508        been changed so that all such subpatterns are automatically treated as
1509        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1510    
1511     4. I had overlooked the fact that, in some locales, there are characters for
1512        which isalpha() is true but neither isupper() nor islower() are true. In
1513        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1514        and ordfeminine) are like this. This affected the treatment of \w and \W
1515        when they appeared in character classes, but not when they appeared outside
1516        a character class. The bit map for "word" characters is now created
1517        separately from the results of isalnum() instead of just taking it from the
1518        upper, lower, and digit maps. (Plus the underscore character, of course.)
1519    
1520     5. The above bug also affected the handling of POSIX character classes such as
1521        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1522        permanent tables. Instead, the bit maps for such a class were previously
1523        created as the appropriate unions of the upper, lower, and digit bitmaps.
1524        Now they are created by subtraction from the [[:word:]] class, which has
1525        its own bitmap.
1526    
1527     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1528        It is created by subtracting the vertical space characters (\x09, \x0a,
1529        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1530        subtraction was done in the overall bitmap for a character class, meaning
1531        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1532        be recognized. This bug has been fixed.
1533    
1534     7. Patches from the folks at Google:
1535    
1536          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1537          real life, but is still worth protecting against".
1538    
1539          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1540          regular expressions".
1541    
1542          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1543          have it.
1544    
1545          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1546          "configure" and the latter not, in order to fix a problem somebody had
1547          with compiling the Arg class on HP-UX.
1548    
1549          (e) Improve the error-handling of the C++ wrapper a little bit.
1550    
1551          (f) New tests for checking recursion limiting.
1552    
1553     8. The pcre_memmove() function, which is used only if the environment does not
1554        have a standard memmove() function (and is therefore rarely compiled),
1555        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1556        returning a result (though PCRE never actually uses the result).
1557    
1558     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1559        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1560        returned instead of calling malloc() with an overflowing number that would
1561        most likely cause subsequent chaos.
1562    
1563    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1564    
1565    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1566        with this option is matched, the nmatch and pmatch options of regexec() are
1567        ignored.
1568    
1569    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1570        provided in case anyone wants to the the POSIX interface with UTF-8
1571        strings.
1572    
1573    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1574        C++ linking (needed for some HP-UX environments).
1575    
1576    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1577        (unused parameter) and in the pcre_printint() function (omitted "default"
1578        switch label when the default is to do nothing).
1579    
1580    15. Added some code to make it possible, when PCRE is compiled as a C++
1581        library, to replace subject pointers for pcre_exec() with a smart pointer
1582        class, thus making it possible to process discontinuous strings.
1583    
1584    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1585        much the same function. They were added by different people who were trying
1586        to make PCRE easy to compile on non-Unix systems. It has been suggested
1587        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1588        for compiling on Windows systems. I have therefore replaced it with
1589        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1590        defaults to "extern" for C or "extern C" for C++, which works fine on
1591        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1592        SCOPE with something explicit in config.h. In addition:
1593    
1594        (a) pcreposix.h still had just "extern" instead of either of these macros;
1595            I have replaced it with PCRE_DATA_SCOPE.
1596    
1597        (b) Functions such as _pcre_xclass(), which are internal to the library,
1598            but external in the C sense, all had PCRE_EXPORT in their definitions.
1599            This is apparently wrong for the Windows case, so I have removed it.
1600            (It makes no difference on Unix-like systems.)
1601    
1602    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1603        of recursive calls to match(). This is different to MATCH_LIMIT because
1604        that limits the total number of calls to match(), not all of which increase
1605        the depth of recursion. Limiting the recursion depth limits the amount of
1606        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1607        when PCRE is compiled, and changed at run time. A patch from Google adds
1608        this functionality to the C++ interface.
1609    
1610    18. Changes to the handling of Unicode character properties:
1611    
1612        (a) Updated the table to Unicode 4.1.0.
1613    
1614        (b) Recognize characters that are not in the table as "Cn" (undefined).
1615    
1616        (c) I revised the way the table is implemented to a much improved format
1617            which includes recognition of ranges. It now supports the ranges that
1618            are defined in UnicodeData.txt, and it also amalgamates other
1619            characters into ranges. This has reduced the number of entries in the
1620            table from around 16,000 to around 3,000, thus reducing its size
1621            considerably. I realized I did not need to use a tree structure after
1622            all - a binary chop search is just as efficient. Having reduced the
1623            number of entries, I extended their size from 6 bytes to 8 bytes to
1624            allow for more data.
1625    
1626        (d) Added support for Unicode script names via properties such as \p{Han}.
1627    
1628    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1629        matching that character.
1630    
1631    20. When matching a repeated Unicode property with a minimum greater than zero,
1632        (for example \pL{2,}), PCRE could look past the end of the subject if it
1633        reached it while seeking the minimum number of characters. This could
1634        happen only if some of the characters were more than one byte long, because
1635        there is a check for at least the minimum number of bytes.
1636    
1637    21. Refactored the implementation of \p and \P so as to be more general, to
1638        allow for more different types of property in future. This has changed the
1639        compiled form incompatibly. Anybody with saved compiled patterns that use
1640        \p or \P will have to recompile them.
1641    
1642    22. Added "Any" and "L&" to the supported property types.
1643    
1644    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1645        but give a compile time error if the value is greater than 0xff.
1646    
1647    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1648        accidentally not being installed or uninstalled.
1649    
1650    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1651        made were to insert the current release number. This seemed silly, because
1652        it made things harder for people building PCRE on systems that don't run
1653        "configure". I have turned pcre.h into a distributed file, no longer built
1654        by "configure", with the version identification directly included. There is
1655        no longer a pcre.h.in file.
1656    
1657        However, this change necessitated a change to the pcre-config script as
1658        well. It is built from pcre-config.in, and one of the substitutions was the
1659        release number. I have updated configure.ac so that ./configure now finds
1660        the release number by grepping pcre.h.
1661    
1662    26. Added the ability to run the tests under valgrind.
1663    
1664    
1665    Version 6.4 05-Sep-05
1666    ---------------------
1667    
1668     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1669        "--" to be printed when multiple files were scanned, even when none of the
1670        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1671        consider it to be a bug, and have restored the previous behaviour.
1672    
1673     2. A couple of code tidies to get rid of compiler warnings.
1674    
1675     3. The pcretest program used to cheat by referring to symbols in the library
1676        whose names begin with _pcre_. These are internal symbols that are not
1677        really supposed to be visible externally, and in some environments it is
1678        possible to suppress them. The cheating is now confined to including
1679        certain files from the library's source, which is a bit cleaner.
1680    
1681     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1682        file's purpose clearer.
1683    
1684     5. Reorganized pcre_ucp_findchar().
1685    
1686    
1687    Version 6.3 15-Aug-05
1688    ---------------------
1689    
1690     1. The file libpcre.pc.in did not have general read permission in the tarball.
1691    
1692     2. There were some problems when building without C++ support:
1693    
1694        (a) If C++ support was not built, "make install" and "make test" still
1695            tried to test it.
1696    
1697        (b) There were problems when the value of CXX was explicitly set. Some
1698            changes have been made to try to fix these, and ...
1699    
1700        (c) --disable-cpp can now be used to explicitly disable C++ support.
1701    
1702        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1703            backslash in a target when C++ was disabled. This confuses some
1704            versions of "make", apparently. Using an intermediate variable solves
1705            this. (Same for CPP_LOBJ.)
1706    
1707     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1708        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1709        necessary on certain architectures.
1710    
1711     4. Added a setting of -export-symbols-regex to the link command to remove
1712        those symbols that are exported in the C sense, but actually are local
1713        within the library, and not documented. Their names all begin with
1714        "_pcre_". This is not a perfect job, because (a) we have to except some
1715        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1716        available (and never for static libraries). I have made a note to try to
1717        find a way round (a) in the future.
1718    
1719    
1720    Version 6.2 01-Aug-05
1721    ---------------------
1722    
1723     1. There was no test for integer overflow of quantifier values. A construction
1724        such as {1111111111111111} would give undefined results. What is worse, if
1725        a minimum quantifier for a parenthesized subpattern overflowed and became
1726        negative, the calculation of the memory size went wrong. This could have
1727        led to memory overwriting.
1728    
1729     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1730    
1731     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1732        operating environments where this matters.
1733    
1734     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1735        PCRE options from within the C++ wrapper.
1736    
1737     5. Named capturing subpatterns were not being correctly counted when a pattern
1738        was compiled. This caused two problems: (a) If there were more than 100
1739        such subpatterns, the calculation of the memory needed for the whole
1740        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1741        back references of the form \12, where the number was greater than 9, were
1742        not recognized as back references, even though there were sufficient
1743        previous subpatterns.
1744    
1745     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1746        versions of gcc, e.g. 2.95.4.
1747    
1748    
1749  Version 6.1 21-Jun-05  Version 6.1 21-Jun-05
1750  ---------------------  ---------------------
1751    

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