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

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