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

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