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revision 15 by nigel, Sat Feb 24 21:38:25 2007 UTC revision 357 by ph10, Tue Jul 8 14:18:28 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.0 02 Jul-08
5    ---------------------
6    
7    1.  Replaced UCP searching code with optimized version as implemented for Ad
8        Muncher (http://www.admuncher.com/) by Peter Kankowski. This uses a two-
9        stage table and inline lookup instead of a function, giving speed ups of 2
10        to 5 times on some simple patterns that I tested. Permission was given to
11        distribute the MultiStage2.py script that generates the tables (it's not in
12        the tarball, but is in the Subversion repository).
13    
14    2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
15        scripts.
16    
17    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
18        a group with a zero qualifier. The result of the study could be incorrect,
19        or the function might crash, depending on the pattern.
20    
21    4.  Caseless matching was not working for non-ASCII characters in back
22        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
23        It now works when Unicode Property Support is available.
24    
25    5.  In pcretest, an escape such as \x{de} in the data was always generating
26        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
27        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
28        truncation.
29    
30    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
31    
32    7.  Added two (int) casts to pcregrep when printing the difference of two
33        pointers, in case they are 64-bit values.
34    
35    
36    Version 7.7 07-May-08
37    ---------------------
38    
39    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
40        a string to a long long, pretend we don't even have a long long." This is
41        done by checking for the strtoq, strtoll, and _strtoi64 functions.
42    
43    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
44        pre-7.6 versions, which defined a global no_arg variable instead of putting
45        it in the RE class. (See also #8 below.)
46    
47    3.  Remove a line of dead code, identified by coverity and reported by Nuno
48        Lopes.
49    
50    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
51    
52        (1) The include/exclude patterns were being applied to the whole pathnames
53            of files, instead of just to the final components.
54    
55        (2) If there was more than one level of directory, the subdirectories were
56            skipped unless they satisfied the include/exclude conditions. This is
57            inconsistent with GNU grep (and could even be seen as contrary to the
58            pcregrep specification - which I improved to make it absolutely clear).
59            The action now is always to scan all levels of directory, and just
60            apply the include/exclude patterns to regular files.
61    
62    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
63        --exclude_dir in the tests to avoid scanning .svn directories.
64    
65    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
66        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
67        doesn't support NULs in patterns.
68    
69    7.  Added some missing "const"s to declarations of static tables in
70        pcre_compile.c and pcre_dfa_exec.c.
71    
72    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
73        caused by fix #2  above. (Subsequently also a second patch to fix the
74        first patch. And a third patch - this was a messy problem.)
75    
76    9.  Applied Craig's patch to remove the use of push_back().
77    
78    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
79        matching function regexec().
80    
81    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
82        which, however, unlike Perl's \g{...}, are subroutine calls, not back
83        references. PCRE supports relative numbers with this syntax (I don't think
84        Oniguruma does).
85    
86    12. Previously, a group with a zero repeat such as (...){0} was completely
87        omitted from the compiled regex. However, this means that if the group
88        was called as a subroutine from elsewhere in the pattern, things went wrong
89        (an internal error was given). Such groups are now left in the compiled
90        pattern, with a new opcode that causes them to be skipped at execution
91        time.
92    
93    13. Added the PCRE_JAVASCRIPT_COMPAT option. This makes the following changes
94        to the way PCRE behaves:
95    
96        (a) A lone ] character is dis-allowed (Perl treats it as data).
97    
98        (b) A back reference to an unmatched subpattern matches an empty string
99            (Perl fails the current match path).
100    
101        (c) A data ] in a character class must be notated as \] because if the
102            first data character in a class is ], it defines an empty class. (In
103            Perl it is not possible to have an empty class.) The empty class []
104            never matches; it forces failure and is equivalent to (*FAIL) or (?!).
105            The negative empty class [^] matches any one character, independently
106            of the DOTALL setting.
107    
108    14. A pattern such as /(?2)[]a()b](abc)/ which had a forward reference to a
109        non-existent subpattern following a character class starting with ']' and
110        containing () gave an internal compiling error instead of "reference to
111        non-existent subpattern". Fortunately, when the pattern did exist, the
112        compiled code was correct. (When scanning forwards to check for the
113        existencd of the subpattern, it was treating the data ']' as terminating
114        the class, so got the count wrong. When actually compiling, the reference
115        was subsequently set up correctly.)
116    
117    15. The "always fail" assertion (?!) is optimzed to (*FAIL) by pcre_compile;
118        it was being rejected as not supported by pcre_dfa_exec(), even though
119        other assertions are supported. I have made pcre_dfa_exec() support
120        (*FAIL).
121    
122    16. The implementation of 13c above involved the invention of a new opcode,
123        OP_ALLANY, which is like OP_ANY but doesn't check the /s flag. Since /s
124        cannot be changed at match time, I realized I could make a small
125        improvement to matching performance by compiling OP_ALLANY instead of
126        OP_ANY for "." when DOTALL was set, and then removing the runtime tests
127        on the OP_ANY path.
128    
129    17. Compiling pcretest on Windows with readline support failed without the
130        following two fixes: (1) Make the unistd.h include conditional on
131        HAVE_UNISTD_H; (2) #define isatty and fileno as _isatty and _fileno.
132    
133    18. Changed CMakeLists.txt and cmake/FindReadline.cmake to arrange for the
134        ncurses library to be included for pcretest when ReadLine support is
135        requested, but also to allow for it to be overridden. This patch came from
136        Daniel Bergström.
137    
138    19. There was a typo in the file ucpinternal.h where f0_rangeflag was defined
139        as 0x00f00000 instead of 0x00800000. Luckily, this would not have caused
140        any errors with the current Unicode tables. Thanks to Peter Kankowski for
141        spotting this.
142    
143    
144    Version 7.6 28-Jan-08
145    ---------------------
146    
147    1.  A character class containing a very large number of characters with
148        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
149        overflow.
150    
151    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
152        HAVE_LONG_LONG is not defined.
153    
154    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
155        bring them up to date and include new features. This patch includes:
156    
157        - Fixed PH's badly added libz and libbz2 support.
158        - Fixed a problem with static linking.
159        - Added pcredemo. [But later removed - see 7 below.]
160        - Fixed dftables problem and added an option.
161        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
162            HAVE_LONG_LONG.
163        - Added readline support for pcretest.
164        - Added an listing of the option settings after cmake has run.
165    
166    4.  A user submitted a patch to Makefile that makes it easy to create
167        "pcre.dll" under mingw when using Configure/Make. I added stuff to
168        Makefile.am that cause it to include this special target, without
169        affecting anything else. Note that the same mingw target plus all
170        the other distribution libraries and programs are now supported
171        when configuring with CMake (see 6 below) instead of with
172        Configure/Make.
173    
174    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
175        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
176        exported in the Windows port". It has not yet been confirmed that the patch
177        solves the problem, but it does no harm.
178    
179    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
180        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
181        with CMake, and also correct the comment about stack recursion.
182    
183    7.  Remove the automatic building of pcredemo from the ./configure system and
184        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
185        of a program that users should build themselves after PCRE is installed, so
186        building it automatically is not really right. What is more, it gave
187        trouble in some build environments.
188    
189    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
190    
191    
192    Version 7.5 10-Jan-08
193    ---------------------
194    
195    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
196        values in parens when parsing an RE using the C++ wrapper."
197    
198    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
199        Characters greater than 255 were excluded from the class instead of being
200        included.
201    
202    3.  The same bug as (2) above applied to negated POSIX classes such as
203        [:^space:].
204    
205    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
206        defined or documented. It seems to have been a typo for PCRE_STATIC, so
207        I have changed it.
208    
209    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
210        first named subpattern) and a construct such as (?&a) would reference the
211        first named subpattern whose name started with "a" (in other words, the
212        length check was missing). Both these problems are fixed. "Subpattern name
213        expected" is now given for (?&) (a zero-length name), and this patch also
214        makes it give the same error for \k'' (previously it complained that that
215        was a reference to a non-existent subpattern).
216    
217    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
218        this is right because (?- can be followed by option settings as well as by
219        digits. I have, however, made the messages clearer.
220    
221    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
222        than the number used in the conditional) now cause a compile-time error.
223        This is actually not compatible with Perl, which accepts such patterns, but
224        treats the conditional as always being FALSE (as PCRE used to), but it
225        seems to me that giving a diagnostic is better.
226    
227    8.  Change "alphameric" to the more common word "alphanumeric" in comments
228        and messages.
229    
230    9.  Fix two occurrences of "backslash" in comments that should have been
231        "backspace".
232    
233    10. Remove two redundant lines of code that can never be obeyed (their function
234        was moved elsewhere).
235    
236    11. The program that makes PCRE's Unicode character property table had a bug
237        which caused it to generate incorrect table entries for sequences of
238        characters that have the same character type, but are in different scripts.
239        It amalgamated them into a single range, with the script of the first of
240        them. In other words, some characters were in the wrong script. There were
241        thirteen such cases, affecting characters in the following ranges:
242    
243          U+002b0 - U+002c1
244          U+0060c - U+0060d
245          U+0061e - U+00612
246          U+0064b - U+0065e
247          U+0074d - U+0076d
248          U+01800 - U+01805
249          U+01d00 - U+01d77
250          U+01d9b - U+01dbf
251          U+0200b - U+0200f
252          U+030fc - U+030fe
253          U+03260 - U+0327f
254          U+0fb46 - U+0fbb1
255          U+10450 - U+1049d
256    
257    12. The -o option (show only the matching part of a line) for pcregrep was not
258        compatible with GNU grep in that, if there was more than one match in a
259        line, it showed only the first of them. It now behaves in the same way as
260        GNU grep.
261    
262    13. If the -o and -v options were combined for pcregrep, it printed a blank
263        line for every non-matching line. GNU grep prints nothing, and pcregrep now
264        does the same. The return code can be used to tell if there were any
265        non-matching lines.
266    
267    14. Added --file-offsets and --line-offsets to pcregrep.
268    
269    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
270        infinitely looping recursion. The bug was that positive lookaheads were not
271        being skipped when checking for a possible empty match (negative lookaheads
272        and both kinds of lookbehind were skipped).
273    
274    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
275        inclusion of <windows.h> to before rather than after the definition of
276        INVALID_FILE_ATTRIBUTES (patch from David Byron).
277    
278    17. Specifying a possessive quantifier with a specific limit for a Unicode
279        character property caused pcre_compile() to compile bad code, which led at
280        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
281        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
282        caused the error; without that there was no problem.
283    
284    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
285    
286    19. Added --enable-pcretest-libreadline.
287    
288    20. In pcrecpp.cc, the variable 'count' was incremented twice in
289        RE::GlobalReplace(). As a result, the number of replacements returned was
290        double what it should be. I removed one of the increments, but Craig sent a
291        later patch that removed the other one (the right fix) and added unit tests
292        that check the return values (which was not done before).
293    
294    21. Several CMake things:
295    
296        (1) Arranged that, when cmake is used on Unix, the libraries end up with
297            the names libpcre and libpcreposix, not just pcre and pcreposix.
298    
299        (2) The above change means that pcretest and pcregrep are now correctly
300            linked with the newly-built libraries, not previously installed ones.
301    
302        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
303    
304    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
305        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
306        UTF-8 newline character). The key issue is that the pattern starts .*;
307        this means that the match must be either at the beginning, or after a
308        newline. The bug was in the code for advancing after a failed match and
309        checking that the new position followed a newline. It was not taking
310        account of UTF-8 characters correctly.
311    
312    23. PCRE was behaving differently from Perl in the way it recognized POSIX
313        character classes. PCRE was not treating the sequence [:...:] as a
314        character class unless the ... were all letters. Perl, however, seems to
315        allow any characters between [: and :], though of course it rejects as
316        unknown any "names" that contain non-letters, because all the known class
317        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
318        for example, whereas PCRE did not - it did not recognize a POSIX character
319        class. This seemed a bit dangerous, so the code has been changed to be
320        closer to Perl. The behaviour is not identical to Perl, because PCRE will
321        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
322        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
323        Perl does, and where it didn't before.
324    
325    24. Rewrite so as to remove the single use of %n from pcregrep because in some
326        Windows environments %n is disabled by default.
327    
328    
329    Version 7.4 21-Sep-07
330    ---------------------
331    
332    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
333        means that a class such as [\s] counted as "explicit reference to CR or
334        LF". That isn't really right - the whole point of the change was to try to
335        help when there was an actual mention of one of the two characters. So now
336        the change happens only if \r or \n (or a literal CR or LF) character is
337        encountered.
338    
339    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
340        of both had grown to the point where there were only 3 bits left.
341        Fortunately, there was spare space in the data structure, and so I have
342        moved the internal flags into a new 16-bit field to free up more option
343        bits.
344    
345    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
346        but did not set the internal JCHANGED flag - either of these is enough to
347        control the way the "get" function works - but the PCRE_INFO_JCHANGED
348        facility is supposed to tell if (?J) was ever used, so now (?J) at the
349        start sets both bits.
350    
351    4.  Added options (at build time, compile time, exec time) to change \R from
352        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
353    
354    5.  doc/pcresyntax.html was missing from the distribution.
355    
356    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
357        compatibility, even though it is no longer used.
358    
359    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
360        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
361        windows.h file is present (where different names are used). [This was
362        reversed later after testing - see 16 below.]
363    
364    8.  Changed all #include <config.h> to #include "config.h". There were also
365        some further <pcre.h> cases that I changed to "pcre.h".
366    
367    9.  When pcregrep was used with the --colour option, it missed the line ending
368        sequence off the lines that it output.
369    
370    10. It was pointed out to me that arrays of string pointers cause lots of
371        relocations when a shared library is dynamically loaded. A technique of
372        using a single long string with a table of offsets can drastically reduce
373        these. I have refactored PCRE in four places to do this. The result is
374        dramatic:
375    
376          Originally:                          290
377          After changing UCP table:            187
378          After changing error message table:   43
379          After changing table of "verbs"       36
380          After changing table of Posix names   22
381    
382        Thanks to the folks working on Gregex for glib for this insight.
383    
384    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
385        unicode-properties was also set.
386    
387    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
388    
389    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
390        checked only for CRLF.
391    
392    14. Added casts to pcretest.c to avoid compiler warnings.
393    
394    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
395    
396    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
397        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
398        entirely. This removes changes made in 7 above.
399    
400    17. The CMake files have been updated, and there is now more information about
401        building with CMake in the NON-UNIX-USE document.
402    
403    
404    Version 7.3 28-Aug-07
405    ---------------------
406    
407     1. In the rejigging of the build system that eventually resulted in 7.1, the
408        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
409        brackets there is not right, since it causes compilers to look for an
410        installed pcre.h, not the version that is in the source that is being
411        compiled (which of course may be different). I have changed it back to:
412    
413          #include "pcre.h"
414    
415        I have a vague recollection that the change was concerned with compiling in
416        different directories, but in the new build system, that is taken care of
417        by the VPATH setting the Makefile.
418    
419     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
420        when the subject happened to end in the byte 0x85 (e.g. if the last
421        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
422        characters but of course it shouldn't be taken as a newline when it is part
423        of another character. The bug was that, for an unlimited repeat of . in
424        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
425        characters when looking for a newline.
426    
427     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
428    
429     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
430        in debug output.
431    
432     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
433        long printing in the pcrecpp unittest when running under MinGW.
434    
435     6. ESC_K was left out of the EBCDIC table.
436    
437     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
438        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
439        limit also applies to "virtual nesting" when a pattern is recursive, and in
440        this case 1000 isn't so big. I have been able to remove this limit at the
441        expense of backing off one optimization in certain circumstances. Normally,
442        when pcre_exec() would call its internal match() function recursively and
443        immediately return the result unconditionally, it uses a "tail recursion"
444        feature to save stack. However, when a subpattern that can match an empty
445        string has an unlimited repetition quantifier, it no longer makes this
446        optimization. That gives it a stack frame in which to save the data for
447        checking that an empty string has been matched. Previously this was taken
448        from the 1000-entry workspace that had been reserved. So now there is no
449        explicit limit, but more stack is used.
450    
451     8. Applied Daniel's patches to solve problems with the import/export magic
452        syntax that is required for Windows, and which was going wrong for the
453        pcreposix and pcrecpp parts of the library. These were overlooked when this
454        problem was solved for the main library.
455    
456     9. There were some crude static tests to avoid integer overflow when computing
457        the size of patterns that contain repeated groups with explicit upper
458        limits. As the maximum quantifier is 65535, the maximum group length was
459        set at 30,000 so that the product of these two numbers did not overflow a
460        32-bit integer. However, it turns out that people want to use groups that
461        are longer than 30,000 bytes (though not repeat them that many times).
462        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
463        made it possible to implement the integer overflow checks in a much more
464        dynamic way, which I have now done. The artificial limitation on group
465        length has been removed - we now have only the limit on the total length of
466        the compiled pattern, which depends on the LINK_SIZE setting.
467    
468    10. Fixed a bug in the documentation for get/copy named substring when
469        duplicate names are permitted. If none of the named substrings are set, the
470        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
471        empty string.
472    
473    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
474        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
475        because the ] is interpreted as the first data character and the
476        terminating ] is not found. PCRE has been made compatible with Perl in this
477        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
478        cause memory overwriting.
479    
480    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
481        string has been matched (to stop an infinite loop). It was not recognizing
482        a conditional subpattern that could match an empty string if that
483        subpattern was within another subpattern. For example, it looped when
484        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
485        condition was not nested. This bug has been fixed.
486    
487    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
488        past the start of the subject in the presence of bytes with the top bit
489        set, for example "\x8aBCD".
490    
491    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
492        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
493    
494    14. Optimized (?!) to (*FAIL).
495    
496    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
497        This restricts code points to be within the range 0 to 0x10FFFF, excluding
498        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
499        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
500        does: it's just the validity check that is more restrictive.
501    
502    16. Inserted checks for integer overflows during escape sequence (backslash)
503        processing, and also fixed erroneous offset values for syntax errors during
504        backslash processing.
505    
506    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
507        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
508    
509    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
510        caused an overrun.
511    
512    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
513        something other than just ASCII characters) inside a group that had an
514        unlimited repeat caused a loop at compile time (while checking to see
515        whether the group could match an empty string).
516    
517    20. Debugging a pattern containing \p or \P could cause a crash. For example,
518        [\P{Any}] did so. (Error in the code for printing property names.)
519    
520    21. An orphan \E inside a character class could cause a crash.
521    
522    22. A repeated capturing bracket such as (A)? could cause a wild memory
523        reference during compilation.
524    
525    23. There are several functions in pcre_compile() that scan along a compiled
526        expression for various reasons (e.g. to see if it's fixed length for look
527        behind). There were bugs in these functions when a repeated \p or \P was
528        present in the pattern. These operators have additional parameters compared
529        with \d, etc, and these were not being taken into account when moving along
530        the compiled data. Specifically:
531    
532        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
533            length.
534    
535        (b) An item such as \pL+ within a repeated group could cause crashes or
536            loops.
537    
538        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
539            "reference to non-existent subpattern" error.
540    
541        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
542    
543    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
544        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
545    
546    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
547    
548    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
549        character were causing crashes (broken optimization).
550    
551    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
552        \p or \P) caused a compile-time loop.
553    
554    28. More problems have arisen in unanchored patterns when CRLF is a valid line
555        break. For example, the unstudied pattern [\r\n]A does not match the string
556        "\r\nA" because change 7.0/46 below moves the current point on by two
557        characters after failing to match at the start. However, the pattern \nA
558        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
559        the same is true. There doesn't seem any very clean way out of this, but
560        what I have chosen to do makes the common cases work: PCRE now takes note
561        of whether there can be an explicit match for \r or \n anywhere in the
562        pattern, and if so, 7.0/46 no longer applies. As part of this change,
563        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
564        pattern has explicit CR or LF references.
565    
566    29. Added (*CR) etc for changing newline setting at start of pattern.
567    
568    
569    Version 7.2 19-Jun-07
570    ---------------------
571    
572     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
573        which is apparently normally available under Windows.
574    
575     2. Re-jig the pcregrep tests with different newline settings in an attempt
576        to make them independent of the local environment's newline setting.
577    
578     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
579    
580     4. Some of the "internals" tests were previously cut out when the link size
581        was not 2, because the output contained actual offsets. The recent new
582        "Z" feature of pcretest means that these can be cut out, making the tests
583        usable with all link sizes.
584    
585     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
586        stack recursion. This gives a massive performance boost under BSD, but just
587        a small improvement under Linux. However, it saves one field in the frame
588        in all cases.
589    
590     6. Added more features from the forthcoming Perl 5.10:
591    
592        (a) (?-n) (where n is a string of digits) is a relative subroutine or
593            recursion call. It refers to the nth most recently opened parentheses.
594    
595        (b) (?+n) is also a relative subroutine call; it refers to the nth next
596            to be opened parentheses.
597    
598        (c) Conditions that refer to capturing parentheses can be specified
599            relatively, for example, (?(-2)... or (?(+3)...
600    
601        (d) \K resets the start of the current match so that everything before
602            is not part of it.
603    
604        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
605    
606        (f) \g{name} is another synonym - part of Perl 5.10's unification of
607            reference syntax.
608    
609        (g) (?| introduces a group in which the numbering of parentheses in each
610            alternative starts with the same number.
611    
612        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
613    
614     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
615        PCRE_INFO_JCHANGED.
616    
617     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
618        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
619        for detecting groups that can match an empty string.
620    
621     9. A pattern with a very large number of alternatives (more than several
622        hundred) was running out of internal workspace during the pre-compile
623        phase, where pcre_compile() figures out how much memory will be needed. A
624        bit of new cunning has reduced the workspace needed for groups with
625        alternatives. The 1000-alternative test pattern now uses 12 bytes of
626        workspace instead of running out of the 4096 that are available.
627    
628    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
629    
630    11. Applied patch from Google to remove an optimization that didn't quite work.
631        The report of the bug said:
632    
633          pcrecpp::RE("a*").FullMatch("aaa") matches, while
634          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
635          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
636    
637    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
638        it matched the wrong number of bytes.
639    
640    
641    Version 7.1 24-Apr-07
642    ---------------------
643    
644     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
645        that is more "standard", making use of automake and other Autotools. There
646        is some re-arrangement of the files and adjustment of comments consequent
647        on this.
648    
649     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
650        for recursive directory scanning broke on some systems because the files
651        are not scanned in any specific order and on different systems the order
652        was different. A call to "sort" has been inserted into RunGrepTest for the
653        approprate test as a short-term fix. In the longer term there may be an
654        alternative.
655    
656     3. I had an email from Eric Raymond about problems translating some of PCRE's
657        man pages to HTML (despite the fact that I distribute HTML pages, some
658        people do their own conversions for various reasons). The problems
659        concerned the use of low-level troff macros .br and .in. I have therefore
660        removed all such uses from the man pages (some were redundant, some could
661        be replaced by .nf/.fi pairs). The 132html script that I use to generate
662        HTML has been updated to handle .nf/.fi and to complain if it encounters
663        .br or .in.
664    
665     4. Updated comments in configure.ac that get placed in config.h.in and also
666        arranged for config.h to be included in the distribution, with the name
667        config.h.generic, for the benefit of those who have to compile without
668        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
669    
670     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
671        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
672        makevp.bat for the current PCRE, using the additional files
673        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
674    
675     6. A Windows user reported a minor discrepancy with test 2, which turned out
676        to be caused by a trailing space on an input line that had got lost in his
677        copy. The trailing space was an accident, so I've just removed it.
678    
679     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
680        that is needed.
681    
682     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
683        as "const" (a) because they are and (b) because it helps the PHP
684        maintainers who have recently made a script to detect big data structures
685        in the php code that should be moved to the .rodata section. I remembered
686        to update Builducptable as well, so it won't revert if ucptable.h is ever
687        re-created.
688    
689     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
690        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
691        order to be able to cut out the UTF-8 tables in the latter when UTF-8
692        support is not required. This saves 1.5-2K of code, which is important in
693        some applications.
694    
695        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
696        so as not to refer to the tables, even though these functions will never be
697        called when UTF-8 support is disabled. Otherwise there are problems with a
698        shared library.
699    
700    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
701    
702        (a) It was defining its arguments as char * instead of void *.
703    
704        (b) It was assuming that all moves were upwards in memory; this was true
705            a long time ago when I wrote it, but is no longer the case.
706    
707        The emulated memove() is provided for those environments that have neither
708        memmove() nor bcopy(). I didn't think anyone used it these days, but that
709        is clearly not the case, as these two bugs were recently reported.
710    
711    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
712        and Detrail to create the HTML documentation, the .txt form of the man
713        pages, and it removes trailing spaces from listed files. It also creates
714        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
715        case, it wraps all the #defines with #ifndefs. This script should be run
716        before "make dist".
717    
718    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
719        with Unicode property support.
720    
721        (a) For a maximizing quantifier, if the two different cases of the
722            character were of different lengths in their UTF-8 codings (there are
723            some cases like this - I found 11), and the matching function had to
724            back up over a mixture of the two cases, it incorrectly assumed they
725            were both the same length.
726    
727        (b) When PCRE was configured to use the heap rather than the stack for
728            recursion during matching, it was not correctly preserving the data for
729            the other case of a UTF-8 character when checking ahead for a match
730            while processing a minimizing repeat. If the check also involved
731            matching a wide character, but failed, corruption could cause an
732            erroneous result when trying to check for a repeat of the original
733            character.
734    
735    13. Some tidying changes to the testing mechanism:
736    
737        (a) The RunTest script now detects the internal link size and whether there
738            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
739            values substituted by "configure". (The RunGrepTest script already did
740            this for UTF-8.) The configure.ac script no longer substitutes the
741            relevant variables.
742    
743        (b) The debugging options /B and /D in pcretest show the compiled bytecode
744            with length and offset values. This means that the output is different
745            for different internal link sizes. Test 2 is skipped for link sizes
746            other than 2 because of this, bypassing the problem. Unfortunately,
747            there was also a test in test 3 (the locale tests) that used /B and
748            failed for link sizes other than 2. Rather than cut the whole test out,
749            I have added a new /Z option to pcretest that replaces the length and
750            offset values with spaces. This is now used to make test 3 independent
751            of link size. (Test 2 will be tidied up later.)
752    
753    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
754        segmentation fault instead of returning the appropriate error message.
755    
756    15. In multiline mode when the newline sequence was set to "any", the pattern
757        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
758        This doesn't seem right; it now treats the CRLF combination as the line
759        ending, and so does not match in that case. It's only a pattern such as ^$
760        that would hit this one: something like ^ABC$ would have failed after \r
761        and then tried again after \r\n.
762    
763    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
764        in an attempt to make files that differ only in their line terminators
765        compare equal. This works on Linux.
766    
767    17. Under certain error circumstances pcregrep might try to free random memory
768        as it exited. This is now fixed, thanks to valgrind.
769    
770    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
771        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
772        was because its rules for how to advance for /g after matching an empty
773        string at the end of a line did not allow for this case. They now check for
774        it specially.
775    
776    20. pcretest is supposed to handle patterns and data of any length, by
777        extending its buffers when necessary. It was getting this wrong when the
778        buffer for a data line had to be extended.
779    
780    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
781        CRLF as a newline sequence.
782    
783    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
784        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
785        I have nevertheless tidied it up.
786    
787    23. Added some casts to kill warnings from HP-UX ia64 compiler.
788    
789    24. Added a man page for pcre-config.
790    
791    
792    Version 7.0 19-Dec-06
793    ---------------------
794    
795     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
796        moving to gcc 4.1.1.
797    
798     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
799        sys/time.h, which is documented as needed for this function. It doesn't
800        seem to matter on Linux, but it showed up on some releases of OS X.
801    
802     3. It seems that there are systems where bytes whose values are greater than
803        127 match isprint() in the "C" locale. The "C" locale should be the
804        default when a C program starts up. In most systems, only ASCII printing
805        characters match isprint(). This difference caused the output from pcretest
806        to vary, making some of the tests fail. I have changed pcretest so that:
807    
808        (a) When it is outputting text in the compiled version of a pattern, bytes
809            other than 32-126 are always shown as hex escapes.
810    
811        (b) When it is outputting text that is a matched part of a subject string,
812            it does the same, unless a different locale has been set for the match
813            (using the /L modifier). In this case, it uses isprint() to decide.
814    
815     4. Fixed a major bug that caused incorrect computation of the amount of memory
816        required for a compiled pattern when options that changed within the
817        pattern affected the logic of the preliminary scan that determines the
818        length. The relevant options are -x, and -i in UTF-8 mode. The result was
819        that the computed length was too small. The symptoms of this bug were
820        either the PCRE error "internal error: code overflow" from pcre_compile(),
821        or a glibc crash with a message such as "pcretest: free(): invalid next
822        size (fast)". Examples of patterns that provoked this bug (shown in
823        pcretest format) are:
824    
825          /(?-x: )/x
826          /(?x)(?-x: \s*#\s*)/
827          /((?i)[\x{c0}])/8
828          /(?i:[\x{c0}])/8
829    
830        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
831        is now done differently.
832    
833     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
834        wrapper classes; (b) implement a new function in the C++ scanner that is
835        more efficient than the old way of doing things because it avoids levels of
836        recursion in the regex matching; (c) add a paragraph to the documentation
837        for the FullMatch() function.
838    
839     6. The escape sequence \n was being treated as whatever was defined as
840        "newline". Not only was this contrary to the documentation, which states
841        that \n is character 10 (hex 0A), but it also went horribly wrong when
842        "newline" was defined as CRLF. This has been fixed.
843    
844     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
845        was being set to -1 for the "end of line" case (supposedly a value that no
846        character can have). Though this value is never used (the check for end of
847        line is "zero bytes in current character"), it caused compiler complaints.
848        I've changed it to 0xffffffff.
849    
850     8. In pcre_version.c, the version string was being built by a sequence of
851        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
852        string (as it is for production releases) called a macro with an empty
853        argument. The C standard says the result of this is undefined. The gcc
854        compiler treats it as an empty string (which was what was wanted) but it is
855        reported that Visual C gives an error. The source has been hacked around to
856        avoid this problem.
857    
858     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
859        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
860        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
861        of them did).
862    
863    10. Originally, pcretest opened its input and output without "b"; then I was
864        told that "b" was needed in some environments, so it was added for release
865        5.0 to both the input and output. (It makes no difference on Unix-like
866        systems.) Later I was told that it is wrong for the input on Windows. I've
867        now abstracted the modes into two macros, to make it easier to fiddle with
868        them, and removed "b" from the input mode under Windows.
869    
870    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
871    
872    12. Added -help and --help to pcretest as an official way of being reminded
873        of the options.
874    
875    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
876        and pcrecpp.cc because they annoy compilers at high warning levels.
877    
878    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
879    
880    15. Fixed an occurrence of == in configure.ac that should have been = (shell
881        scripts are not C programs :-) and which was not noticed because it works
882        on Linux.
883    
884    16. pcretest is supposed to handle any length of pattern and data line (as one
885        line or as a continued sequence of lines) by extending its input buffer if
886        necessary. This feature was broken for very long pattern lines, leading to
887        a string of junk being passed to pcre_compile() if the pattern was longer
888        than about 50K.
889    
890    17. I have done a major re-factoring of the way pcre_compile() computes the
891        amount of memory needed for a compiled pattern. Previously, there was code
892        that made a preliminary scan of the pattern in order to do this. That was
893        OK when PCRE was new, but as the facilities have expanded, it has become
894        harder and harder to keep it in step with the real compile phase, and there
895        have been a number of bugs (see for example, 4 above). I have now found a
896        cunning way of running the real compile function in a "fake" mode that
897        enables it to compute how much memory it would need, while actually only
898        ever using a few hundred bytes of working memory and without too many
899        tests of the mode. This should make future maintenance and development
900        easier. A side effect of this work is that the limit of 200 on the nesting
901        depth of parentheses has been removed (though this was never a serious
902        limitation, I suspect). However, there is a downside: pcre_compile() now
903        runs more slowly than before (30% or more, depending on the pattern). I
904        hope this isn't a big issue. There is no effect on runtime performance.
905    
906    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
907        newline (only possible for the last line of a file) and it was a
908        pattern that set a locale (followed by /Lsomething), pcretest crashed.
909    
910    19. Added additional timing features to pcretest. (1) The -tm option now times
911        matching only, not compiling. (2) Both -t and -tm can be followed, as a
912        separate command line item, by a number that specifies the number of
913        repeats to use when timing. The default is 50000; this gives better
914        precision, but takes uncomfortably long for very large patterns.
915    
916    20. Extended pcre_study() to be more clever in cases where a branch of a
917        subpattern has no definite first character. For example, (a*|b*)[cd] would
918        previously give no result from pcre_study(). Now it recognizes that the
919        first character must be a, b, c, or d.
920    
921    21. There was an incorrect error "recursive call could loop indefinitely" if
922        a subpattern (or the entire pattern) that was being tested for matching an
923        empty string contained only one non-empty item after a nested subpattern.
924        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
925        incorrectly, because the \d was being skipped in the check.
926    
927    22. The pcretest program now has a new pattern option /B and a command line
928        option -b, which is equivalent to adding /B to every pattern. This causes
929        it to show the compiled bytecode, without the additional information that
930        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
931        is the same as /B/I).
932    
933    23. A new optimization is now able automatically to treat some sequences such
934        as a*b as a*+b. More specifically, if something simple (such as a character
935        or a simple class like \d) has an unlimited quantifier, and is followed by
936        something that cannot possibly match the quantified thing, the quantifier
937        is automatically "possessified".
938    
939    24. A recursive reference to a subpattern whose number was greater than 39
940        went wrong under certain circumstances in UTF-8 mode. This bug could also
941        have affected the operation of pcre_study().
942    
943    25. Realized that a little bit of performance could be had by replacing
944        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
945    
946    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
947    
948    27. Possessive quantifiers such as a++ were previously implemented by turning
949        them into atomic groups such as ($>a+). Now they have their own opcodes,
950        which improves performance. This includes the automatically created ones
951        from 23 above.
952    
953    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
954        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
955        the first matched character to be a colon. This applied both to named and
956        numbered groups.
957    
958    29. The ucpinternal.h header file was missing its idempotency #ifdef.
959    
960    30. I was sent a "project" file called libpcre.a.dev which I understand makes
961        building PCRE on Windows easier, so I have included it in the distribution.
962    
963    31. There is now a check in pcretest against a ridiculously large number being
964        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
965        loop, the loop is abandoned.
966    
967    32. Forward references to subpatterns in conditions such as (?(2)...) where
968        subpattern 2 is defined later cause pcre_compile() to search forwards in
969        the pattern for the relevant set of parentheses. This search went wrong
970        when there were unescaped parentheses in a character class, parentheses
971        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
972    
973    33. "Subroutine" calls and backreferences were previously restricted to
974        referencing subpatterns earlier in the regex. This restriction has now
975        been removed.
976    
977    34. Added a number of extra features that are going to be in Perl 5.10. On the
978        whole, these are just syntactic alternatives for features that PCRE had
979        previously implemented using the Python syntax or my own invention. The
980        other formats are all retained for compatibility.
981    
982        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
983            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
984            also .NET compatible.
985    
986        (b) A recursion or subroutine call to a named group can now be defined as
987            (?&name) as well as (?P>name).
988    
989        (c) A backreference to a named group can now be defined as \k<name> or
990            \k'name' as well as (?P=name). The new forms, as well as being in Perl
991            5.10, are also .NET compatible.
992    
993        (d) A conditional reference to a named group can now use the syntax
994            (?(<name>) or (?('name') as well as (?(name).
995    
996        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
997            groups (named and numbered) that are never evaluated inline, but can be
998            called as "subroutines" from elsewhere. In effect, the DEFINE condition
999            is always false. There may be only one alternative in such a group.
1000    
1001        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
1002            as the simple (?(R). The condition is true only if the most recent
1003            recursion is that of the given number or name. It does not search out
1004            through the entire recursion stack.
1005    
1006        (g) The escape \gN or \g{N} has been added, where N is a positive or
1007            negative number, specifying an absolute or relative reference.
1008    
1009    35. Tidied to get rid of some further signed/unsigned compiler warnings and
1010        some "unreachable code" warnings.
1011    
1012    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
1013        things, this adds five new scripts.
1014    
1015    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
1016        There were also incompatibilities regarding the handling of \Q..\E inside
1017        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
1018        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
1019    
1020    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
1021        matches an empty string, and forcibly breaks the loop. There were bugs in
1022        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
1023        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
1024        separate and independent bugs (that affected different cases) have been
1025        fixed.
1026    
1027    39. Refactored the code to abolish the use of different opcodes for small
1028        capturing bracket numbers. This is a tidy that I avoided doing when I
1029        removed the limit on the number of capturing brackets for 3.5 back in 2001.
1030        The new approach is not only tidier, it makes it possible to reduce the
1031        memory needed to fix the previous bug (38).
1032    
1033    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
1034        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
1035        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
1036        mode.
1037    
1038    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
1039        report.
1040    
1041    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
1042        copy construction and assignment in the C++ wrapper.
1043    
1044    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
1045        couple of bugs that could have given wrong results in the "--newline=crlf"
1046        case.
1047    
1048    44. Added a number of casts and did some reorganization of signed/unsigned int
1049        variables following suggestions from Dair Grant. Also renamed the variable
1050        "this" as "item" because it is a C++ keyword.
1051    
1052    45. Arranged for dftables to add
1053    
1054          #include "pcre_internal.h"
1055    
1056        to pcre_chartables.c because without it, gcc 4.x may remove the array
1057        definition from the final binary if PCRE is built into a static library and
1058        dead code stripping is activated.
1059    
1060    46. For an unanchored pattern, if a match attempt fails at the start of a
1061        newline sequence, and the newline setting is CRLF or ANY, and the next two
1062        characters are CRLF, advance by two characters instead of one.
1063    
1064    
1065    Version 6.7 04-Jul-06
1066    ---------------------
1067    
1068     1. In order to handle tests when input lines are enormously long, pcretest has
1069        been re-factored so that it automatically extends its buffers when
1070        necessary. The code is crude, but this _is_ just a test program. The
1071        default size has been increased from 32K to 50K.
1072    
1073     2. The code in pcre_study() was using the value of the re argument before
1074        testing it for NULL. (Of course, in any sensible call of the function, it
1075        won't be NULL.)
1076    
1077     3. The memmove() emulation function in pcre_internal.h, which is used on
1078        systems that lack both memmove() and bcopy() - that is, hardly ever -
1079        was missing a "static" storage class specifier.
1080    
1081     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1082        containing an extended class (one that cannot be represented by a bitmap
1083        because it contains high-valued characters or Unicode property items, e.g.
1084        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1085        pattern, but PCRE should not loop if you do not (it no longer does).
1086        [Detail: two cases were found: (a) a repeated subpattern containing an
1087        extended class; (b) a recursive reference to a subpattern that followed a
1088        previous extended class. It wasn't skipping over the extended class
1089        correctly when UTF-8 mode was not set.]
1090    
1091     5. A negated single-character class was not being recognized as fixed-length
1092        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1093        compile error "lookbehind assertion is not fixed length".
1094    
1095     6. The RunPerlTest auxiliary script was showing an unexpected difference
1096        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1097        write a Perl script that can interpret lines of an input file either as
1098        byte characters or as UTF-8, which is what "perltest" was being required to
1099        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1100        can't do is switch easily at run time between having the "use utf8;" pragma
1101        or not. In the end, I fudged it by using the RunPerlTest script to insert
1102        "use utf8;" explicitly for the UTF-8 tests.
1103    
1104     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1105        the end of the subject string, contrary to the documentation and to what
1106        Perl does. This was true of both matching functions. Now it matches only at
1107        the start of the subject and immediately after *internal* newlines.
1108    
1109     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1110        a pointer to an int instead of a pointer to an unsigned long int. This
1111        caused problems on 64-bit systems.
1112    
1113     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1114        instance of the 'standard' template library not being so standard".
1115    
1116    10. There was no check on the number of named subpatterns nor the maximum
1117        length of a subpattern name. The product of these values is used to compute
1118        the size of the memory block for a compiled pattern. By supplying a very
1119        long subpattern name and a large number of named subpatterns, the size
1120        computation could be caused to overflow. This is now prevented by limiting
1121        the length of names to 32 characters, and the number of named subpatterns
1122        to 10,000.
1123    
1124    11. Subpatterns that are repeated with specific counts have to be replicated in
1125        the compiled pattern. The size of memory for this was computed from the
1126        length of the subpattern and the repeat count. The latter is limited to
1127        65535, but there was no limit on the former, meaning that integer overflow
1128        could in principle occur. The compiled length of a repeated subpattern is
1129        now limited to 30,000 bytes in order to prevent this.
1130    
1131    12. Added the optional facility to have named substrings with the same name.
1132    
1133    13. Added the ability to use a named substring as a condition, using the
1134        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1135        are numbers (not recommended). Forward references are permitted.
1136    
1137    14. Added forward references in named backreferences (if you see what I mean).
1138    
1139    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1140        pattern could run off the end of the subject. For example, the pattern
1141        "(?s)(.{1,5})"8 did this with the subject "ab".
1142    
1143    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1144        PCRE_CASELESS was set when matching characters that were quantified with ?
1145        or *.
1146    
1147    17. A character class other than a single negated character that had a minimum
1148        but no maximum quantifier - for example [ab]{6,} - was not handled
1149        correctly by pce_dfa_exec(). It would match only one character.
1150    
1151    18. A valid (though odd) pattern that looked like a POSIX character
1152        class but used an invalid character after [ (for example [[,abc,]]) caused
1153        pcre_compile() to give the error "Failed: internal error: code overflow" or
1154        in some cases to crash with a glibc free() error. This could even happen if
1155        the pattern terminated after [[ but there just happened to be a sequence of
1156        letters, a binary zero, and a closing ] in the memory that followed.
1157    
1158    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1159        over the years. Originally (before any Unicode support), just the bottom 8
1160        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1161        output from "man perlunicode" includes this:
1162    
1163          The regular expression compiler produces polymorphic opcodes.  That
1164          is, the pattern adapts to the data and automatically switches to
1165          the Unicode character scheme when presented with Unicode data--or
1166          instead uses a traditional byte scheme when presented with byte
1167          data.
1168    
1169        Sadly, a wide octal escape does not cause a switch, and in a string with
1170        no other multibyte characters, these octal escapes are treated as before.
1171        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1172        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1173        Unicode string.
1174    
1175        I have not perpetrated such confusion in PCRE. Up till now, it took just
1176        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1177        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1178        translate to the appropriate multibyte character.
1179    
1180    29. Applied some refactoring to reduce the number of warnings from Microsoft
1181        and Borland compilers. This has included removing the fudge introduced
1182        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1183        a warning about an unused variable.
1184    
1185    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1186        characters since release 4.0, because Perl (from release 5.004) does not.
1187        [Or at least, is documented not to: some releases seem to be in conflict
1188        with the documentation.] However, when a pattern was studied with
1189        pcre_study() and all its branches started with \s, PCRE still included VT
1190        as a possible starting character. Of course, this did no harm; it just
1191        caused an unnecessary match attempt.
1192    
1193    22. Removed a now-redundant internal flag bit that recorded the fact that case
1194        dependency changed within the pattern. This was once needed for "required
1195        byte" processing, but is no longer used. This recovers a now-scarce options
1196        bit. Also moved the least significant internal flag bit to the most-
1197        significant bit of the word, which was not previously used (hangover from
1198        the days when it was an int rather than a uint) to free up another bit for
1199        the future.
1200    
1201    23. Added support for CRLF line endings as well as CR and LF. As well as the
1202        default being selectable at build time, it can now be changed at runtime
1203        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1204        specify that it is scanning data with non-default line endings.
1205    
1206    24. Changed the definition of CXXLINK to make it agree with the definition of
1207        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1208    
1209    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1210        recursions. This makes a big different to stack usage for some patterns.
1211    
1212    26. If a subpattern containing a named recursion or subroutine reference such
1213        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1214        the space required for the compiled pattern went wrong and gave too small a
1215        value. Depending on the environment, this could lead to "Failed: internal
1216        error: code overflow at offset 49" or "glibc detected double free or
1217        corruption" errors.
1218    
1219    27. Applied patches from Google (a) to support the new newline modes and (b) to
1220        advance over multibyte UTF-8 characters in GlobalReplace.
1221    
1222    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1223        difference for some implementation of PCRE in some Windows version.
1224    
1225    29. Added some extra testing facilities to pcretest:
1226    
1227        \q<number>   in a data line sets the "match limit" value
1228        \Q<number>   in a data line sets the "match recursion limt" value
1229        -S <number>  sets the stack size, where <number> is in megabytes
1230    
1231        The -S option isn't available for Windows.
1232    
1233    
1234    Version 6.6 06-Feb-06
1235    ---------------------
1236    
1237     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1238        in pcreposix.h. I have copied the definition from pcre.h.
1239    
1240     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1241        because pcre.h is no longer a built file.
1242    
1243     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1244        not normally included in the compiled code.
1245    
1246    
1247    Version 6.5 01-Feb-06
1248    ---------------------
1249    
1250     1. When using the partial match feature with pcre_dfa_exec(), it was not
1251        anchoring the second and subsequent partial matches at the new starting
1252        point. This could lead to incorrect results. For example, with the pattern
1253        /1234/, partially matching against "123" and then "a4" gave a match.
1254    
1255     2. Changes to pcregrep:
1256    
1257        (a) All non-match returns from pcre_exec() were being treated as failures
1258            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1259            error message is output. Some extra information is given for the
1260            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1261            probably the only errors that are likely to be caused by users (by
1262            specifying a regex that has nested indefinite repeats, for instance).
1263            If there are more than 20 of these errors, pcregrep is abandoned.
1264    
1265        (b) A binary zero was treated as data while matching, but terminated the
1266            output line if it was written out. This has been fixed: binary zeroes
1267            are now no different to any other data bytes.
1268    
1269        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1270            used to set a locale for matching. The --locale=xxxx long option has
1271            been added (no short equivalent) to specify a locale explicitly on the
1272            pcregrep command, overriding the environment variables.
1273    
1274        (d) When -B was used with -n, some line numbers in the output were one less
1275            than they should have been.
1276    
1277        (e) Added the -o (--only-matching) option.
1278    
1279        (f) If -A or -C was used with -c (count only), some lines of context were
1280            accidentally printed for the final match.
1281    
1282        (g) Added the -H (--with-filename) option.
1283    
1284        (h) The combination of options -rh failed to suppress file names for files
1285            that were found from directory arguments.
1286    
1287        (i) Added the -D (--devices) and -d (--directories) options.
1288    
1289        (j) Added the -F (--fixed-strings) option.
1290    
1291        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1292    
1293        (l) Added the --colo(u)r option.
1294    
1295        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1296            is not present by default.
1297    
1298     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1299        items such as (?R) or (?1), when the recursion could match a number of
1300        alternatives. If it matched one of the alternatives, but subsequently,
1301        outside the recursion, there was a failure, the code tried to back up into
1302        the recursion. However, because of the way PCRE is implemented, this is not
1303        possible, and the result was an incorrect result from the match.
1304    
1305        In order to prevent this happening, the specification of recursion has
1306        been changed so that all such subpatterns are automatically treated as
1307        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1308    
1309     4. I had overlooked the fact that, in some locales, there are characters for
1310        which isalpha() is true but neither isupper() nor islower() are true. In
1311        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1312        and ordfeminine) are like this. This affected the treatment of \w and \W
1313        when they appeared in character classes, but not when they appeared outside
1314        a character class. The bit map for "word" characters is now created
1315        separately from the results of isalnum() instead of just taking it from the
1316        upper, lower, and digit maps. (Plus the underscore character, of course.)
1317    
1318     5. The above bug also affected the handling of POSIX character classes such as
1319        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1320        permanent tables. Instead, the bit maps for such a class were previously
1321        created as the appropriate unions of the upper, lower, and digit bitmaps.
1322        Now they are created by subtraction from the [[:word:]] class, which has
1323        its own bitmap.
1324    
1325     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1326        It is created by subtracting the vertical space characters (\x09, \x0a,
1327        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1328        subtraction was done in the overall bitmap for a character class, meaning
1329        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1330        be recognized. This bug has been fixed.
1331    
1332     7. Patches from the folks at Google:
1333    
1334          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1335          real life, but is still worth protecting against".
1336    
1337          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1338          regular expressions".
1339    
1340          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1341          have it.
1342    
1343          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1344          "configure" and the latter not, in order to fix a problem somebody had
1345          with compiling the Arg class on HP-UX.
1346    
1347          (e) Improve the error-handling of the C++ wrapper a little bit.
1348    
1349          (f) New tests for checking recursion limiting.
1350    
1351     8. The pcre_memmove() function, which is used only if the environment does not
1352        have a standard memmove() function (and is therefore rarely compiled),
1353        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1354        returning a result (though PCRE never actually uses the result).
1355    
1356     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1357        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1358        returned instead of calling malloc() with an overflowing number that would
1359        most likely cause subsequent chaos.
1360    
1361    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1362    
1363    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1364        with this option is matched, the nmatch and pmatch options of regexec() are
1365        ignored.
1366    
1367    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1368        provided in case anyone wants to the the POSIX interface with UTF-8
1369        strings.
1370    
1371    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1372        C++ linking (needed for some HP-UX environments).
1373    
1374    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1375        (unused parameter) and in the pcre_printint() function (omitted "default"
1376        switch label when the default is to do nothing).
1377    
1378    15. Added some code to make it possible, when PCRE is compiled as a C++
1379        library, to replace subject pointers for pcre_exec() with a smart pointer
1380        class, thus making it possible to process discontinuous strings.
1381    
1382    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1383        much the same function. They were added by different people who were trying
1384        to make PCRE easy to compile on non-Unix systems. It has been suggested
1385        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1386        for compiling on Windows systems. I have therefore replaced it with
1387        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1388        defaults to "extern" for C or "extern C" for C++, which works fine on
1389        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1390        SCOPE with something explicit in config.h. In addition:
1391    
1392        (a) pcreposix.h still had just "extern" instead of either of these macros;
1393            I have replaced it with PCRE_DATA_SCOPE.
1394    
1395        (b) Functions such as _pcre_xclass(), which are internal to the library,
1396            but external in the C sense, all had PCRE_EXPORT in their definitions.
1397            This is apparently wrong for the Windows case, so I have removed it.
1398            (It makes no difference on Unix-like systems.)
1399    
1400    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1401        of recursive calls to match(). This is different to MATCH_LIMIT because
1402        that limits the total number of calls to match(), not all of which increase
1403        the depth of recursion. Limiting the recursion depth limits the amount of
1404        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1405        when PCRE is compiled, and changed at run time. A patch from Google adds
1406        this functionality to the C++ interface.
1407    
1408    18. Changes to the handling of Unicode character properties:
1409    
1410        (a) Updated the table to Unicode 4.1.0.
1411    
1412        (b) Recognize characters that are not in the table as "Cn" (undefined).
1413    
1414        (c) I revised the way the table is implemented to a much improved format
1415            which includes recognition of ranges. It now supports the ranges that
1416            are defined in UnicodeData.txt, and it also amalgamates other
1417            characters into ranges. This has reduced the number of entries in the
1418            table from around 16,000 to around 3,000, thus reducing its size
1419            considerably. I realized I did not need to use a tree structure after
1420            all - a binary chop search is just as efficient. Having reduced the
1421            number of entries, I extended their size from 6 bytes to 8 bytes to
1422            allow for more data.
1423    
1424        (d) Added support for Unicode script names via properties such as \p{Han}.
1425    
1426    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1427        matching that character.
1428    
1429    20. When matching a repeated Unicode property with a minimum greater than zero,
1430        (for example \pL{2,}), PCRE could look past the end of the subject if it
1431        reached it while seeking the minimum number of characters. This could
1432        happen only if some of the characters were more than one byte long, because
1433        there is a check for at least the minimum number of bytes.
1434    
1435    21. Refactored the implementation of \p and \P so as to be more general, to
1436        allow for more different types of property in future. This has changed the
1437        compiled form incompatibly. Anybody with saved compiled patterns that use
1438        \p or \P will have to recompile them.
1439    
1440    22. Added "Any" and "L&" to the supported property types.
1441    
1442    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1443        but give a compile time error if the value is greater than 0xff.
1444    
1445    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1446        accidentally not being installed or uninstalled.
1447    
1448    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1449        made were to insert the current release number. This seemed silly, because
1450        it made things harder for people building PCRE on systems that don't run
1451        "configure". I have turned pcre.h into a distributed file, no longer built
1452        by "configure", with the version identification directly included. There is
1453        no longer a pcre.h.in file.
1454    
1455        However, this change necessitated a change to the pcre-config script as
1456        well. It is built from pcre-config.in, and one of the substitutions was the
1457        release number. I have updated configure.ac so that ./configure now finds
1458        the release number by grepping pcre.h.
1459    
1460    26. Added the ability to run the tests under valgrind.
1461    
1462    
1463    Version 6.4 05-Sep-05
1464    ---------------------
1465    
1466     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1467        "--" to be printed when multiple files were scanned, even when none of the
1468        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1469        consider it to be a bug, and have restored the previous behaviour.
1470    
1471     2. A couple of code tidies to get rid of compiler warnings.
1472    
1473     3. The pcretest program used to cheat by referring to symbols in the library
1474        whose names begin with _pcre_. These are internal symbols that are not
1475        really supposed to be visible externally, and in some environments it is
1476        possible to suppress them. The cheating is now confined to including
1477        certain files from the library's source, which is a bit cleaner.
1478    
1479     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1480        file's purpose clearer.
1481    
1482     5. Reorganized pcre_ucp_findchar().
1483    
1484    
1485    Version 6.3 15-Aug-05
1486    ---------------------
1487    
1488     1. The file libpcre.pc.in did not have general read permission in the tarball.
1489    
1490     2. There were some problems when building without C++ support:
1491    
1492        (a) If C++ support was not built, "make install" and "make test" still
1493            tried to test it.
1494    
1495        (b) There were problems when the value of CXX was explicitly set. Some
1496            changes have been made to try to fix these, and ...
1497    
1498        (c) --disable-cpp can now be used to explicitly disable C++ support.
1499    
1500        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1501            backslash in a target when C++ was disabled. This confuses some
1502            versions of "make", apparently. Using an intermediate variable solves
1503            this. (Same for CPP_LOBJ.)
1504    
1505     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1506        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1507        necessary on certain architectures.
1508    
1509     4. Added a setting of -export-symbols-regex to the link command to remove
1510        those symbols that are exported in the C sense, but actually are local
1511        within the library, and not documented. Their names all begin with
1512        "_pcre_". This is not a perfect job, because (a) we have to except some
1513        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1514        available (and never for static libraries). I have made a note to try to
1515        find a way round (a) in the future.
1516    
1517    
1518    Version 6.2 01-Aug-05
1519    ---------------------
1520    
1521     1. There was no test for integer overflow of quantifier values. A construction
1522        such as {1111111111111111} would give undefined results. What is worse, if
1523        a minimum quantifier for a parenthesized subpattern overflowed and became
1524        negative, the calculation of the memory size went wrong. This could have
1525        led to memory overwriting.
1526    
1527     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1528    
1529     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1530        operating environments where this matters.
1531    
1532     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1533        PCRE options from within the C++ wrapper.
1534    
1535     5. Named capturing subpatterns were not being correctly counted when a pattern
1536        was compiled. This caused two problems: (a) If there were more than 100
1537        such subpatterns, the calculation of the memory needed for the whole
1538        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1539        back references of the form \12, where the number was greater than 9, were
1540        not recognized as back references, even though there were sufficient
1541        previous subpatterns.
1542    
1543     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1544        versions of gcc, e.g. 2.95.4.
1545    
1546    
1547    Version 6.1 21-Jun-05
1548    ---------------------
1549    
1550     1. There was one reference to the variable "posix" in pcretest.c that was not
1551        surrounded by "#if !defined NOPOSIX".
1552    
1553     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1554        the cross-check on the old pcre_info() function, for the benefit of the
1555        cut-down version of PCRE that is currently imported into Exim.
1556    
1557     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1558        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1559        patterns that start (?i) but I don't think that matters. The use of (?i) is
1560        just an example; this all applies to the other options as well.
1561    
1562     4. Since libtool seems to echo the compile commands it is issuing, the output
1563        from "make" can be reduced a bit by putting "@" in front of each libtool
1564        compile command.
1565    
1566     5. Patch from the folks at Google for configure.in to be a bit more thorough
1567        in checking for a suitable C++ installation before trying to compile the
1568        C++ stuff. This should fix a reported problem when a compiler was present,
1569        but no suitable headers.
1570    
1571     6. The man pages all had just "PCRE" as their title. I have changed them to
1572        be the relevant file name. I have also arranged that these names are
1573        retained in the file doc/pcre.txt, which is a concatenation in text format
1574        of all the man pages except the little individual ones for each function.
1575    
1576     7. The NON-UNIX-USE file had not been updated for the different set of source
1577        files that come with release 6. I also added a few comments about the C++
1578        wrapper.
1579    
1580    
1581    Version 6.0 07-Jun-05
1582    ---------------------
1583    
1584     1. Some minor internal re-organization to help with my DFA experiments.
1585    
1586     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1587        didn't matter for the library itself when fully configured, but did matter
1588        when compiling without UCP support, or within Exim, where the ucp files are
1589        not imported.
1590    
1591     3. Refactoring of the library code to split up the various functions into
1592        different source modules. The addition of the new DFA matching code (see
1593        below) to a single monolithic source would have made it really too
1594        unwieldy, quite apart from causing all the code to be include in a
1595        statically linked application, when only some functions are used. This is
1596        relevant even without the DFA addition now that patterns can be compiled in
1597        one application and matched in another.
1598    
1599        The downside of splitting up is that there have to be some external
1600        functions and data tables that are used internally in different modules of
1601        the library but which are not part of the API. These have all had their
1602        names changed to start with "_pcre_" so that they are unlikely to clash
1603        with other external names.
1604    
1605     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1606        a different (DFA) algorithm. Although it is slower than the original
1607        function, it does have some advantages for certain types of matching
1608        problem.
1609    
1610     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1611        including restarting after a partial match.
1612    
1613     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1614        defined when compiling for Windows was sent to me. I have put it into the
1615        code, though I have no means of testing or verifying it.
1616    
1617     7. Added the pcre_refcount() auxiliary function.
1618    
1619     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1620        match before or at the first newline in the subject string. In pcretest,
1621        the /f option on a pattern can be used to set this.
1622    
1623     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1624        would behave wrongly. This has been present in PCRE since release 4.0.
1625    
1626    10. A number of changes to the pcregrep command:
1627    
1628        (a) Refactored how -x works; insert ^(...)$ instead of setting
1629            PCRE_ANCHORED and checking the length, in preparation for adding
1630            something similar for -w.
1631    
1632        (b) Added the -w (match as a word) option.
1633    
1634        (c) Refactored the way lines are read and buffered so as to have more
1635            than one at a time available.
1636    
1637        (d) Implemented a pcregrep test script.
1638    
1639        (e) Added the -M (multiline match) option. This allows patterns to match
1640            over several lines of the subject. The buffering ensures that at least
1641            8K, or the rest of the document (whichever is the shorter) is available
1642            for matching (and similarly the previous 8K for lookbehind assertions).
1643    
1644        (f) Changed the --help output so that it now says
1645    
1646              -w, --word-regex(p)
1647    
1648            instead of two lines, one with "regex" and the other with "regexp"
1649            because that confused at least one person since the short forms are the
1650            same. (This required a bit of code, as the output is generated
1651            automatically from a table. It wasn't just a text change.)
1652    
1653        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1654            option but starts with a hyphen. Could be a pattern or a path name
1655            starting with a hyphen, for instance.
1656    
1657        (h) "-" can be given as a file name to represent stdin.
1658    
1659        (i) When file names are being printed, "(standard input)" is used for
1660            the standard input, for compatibility with GNU grep. Previously
1661            "<stdin>" was used.
1662    
1663        (j) The option --label=xxx can be used to supply a name to be used for
1664            stdin when file names are being printed. There is no short form.
1665    
1666        (k) Re-factored the options decoding logic because we are going to add
1667            two more options that take data. Such options can now be given in four
1668            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1669    
1670        (l) Added the -A, -B, and -C options for requesting that lines of context
1671            around matches be printed.
1672    
1673        (m) Added the -L option to print the names of files that do not contain
1674            any matching lines, that is, the complement of -l.
1675    
1676        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1677            continue to scan other files.
1678    
1679        (o) The -s option was incorrectly implemented. For compatibility with other
1680            greps, it now suppresses the error message for a non-existent or non-
1681            accessible file (but not the return code). There is a new option called
1682            -q that suppresses the output of matching lines, which was what -s was
1683            previously doing.
1684    
1685        (p) Added --include and --exclude options to specify files for inclusion
1686            and exclusion when recursing.
1687    
1688    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1689        Hopefully, it now does.
1690    
1691    12. Missing cast in pcre_study().
1692    
1693    13. Added an "uninstall" target to the makefile.
1694    
1695    14. Replaced "extern" in the function prototypes in Makefile.in with
1696        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1697        world, but is set differently for Windows.
1698    
1699    15. Added a second compiling function called pcre_compile2(). The only
1700        difference is that it has an extra argument, which is a pointer to an
1701        integer error code. When there is a compile-time failure, this is set
1702        non-zero, in addition to the error test pointer being set to point to an
1703        error message. The new argument may be NULL if no error number is required
1704        (but then you may as well call pcre_compile(), which is now just a
1705        wrapper). This facility is provided because some applications need a
1706        numeric error indication, but it has also enabled me to tidy up the way
1707        compile-time errors are handled in the POSIX wrapper.
1708    
1709    16. Added VPATH=.libs to the makefile; this should help when building with one
1710        prefix path and installing with another. (Or so I'm told by someone who
1711        knows more about this stuff than I do.)
1712    
1713    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1714        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1715        match everything, including newlines. This is not POSIX-compatible, but
1716        somebody wanted the feature. From pcretest it can be activated by using
1717        both the P and the s flags.
1718    
1719    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1720    
1721    19. libpcre.pc was being incorrectly installed as executable.
1722    
1723    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1724        it now also looks for '\r' so that it will work unmodified on Windows.
1725    
1726    21. Added Google's contributed C++ wrapper to the distribution.
1727    
1728    22. Added some untidy missing memory free() calls in pcretest, to keep
1729        Electric Fence happy when testing.
1730    
1731    
1732    
1733    Version 5.0 13-Sep-04
1734    ---------------------
1735    
1736     1. Internal change: literal characters are no longer packed up into items
1737        containing multiple characters in a single byte-string. Each character
1738        is now matched using a separate opcode. However, there may be more than one
1739        byte in the character in UTF-8 mode.
1740    
1741     2. The pcre_callout_block structure has two new fields: pattern_position and
1742        next_item_length. These contain the offset in the pattern to the next match
1743        item, and its length, respectively.
1744    
1745     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1746        insertion of callouts before each pattern item. Added the /C option to
1747        pcretest to make use of this.
1748    
1749     4. On the advice of a Windows user, the lines
1750    
1751          #if defined(_WIN32) || defined(WIN32)
1752          _setmode( _fileno( stdout ), 0x8000 );
1753          #endif  /* defined(_WIN32) || defined(WIN32) */
1754    
1755        have been added to the source of pcretest. This apparently does useful
1756        magic in relation to line terminators.
1757    
1758     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1759        for the benefit of those environments where the "b" makes a difference.
1760    
1761     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1762        to know about it. I have put a hack into configure.in that adds in code
1763        to set GCC=yes if CC=icc. This seems to end up at a point in the
1764        generated configure script that is early enough to affect the setting of
1765        compiler options, which is what is needed, but I have no means of testing
1766        whether it really works. (The user who reported this had patched the
1767        generated configure script, which of course I cannot do.)
1768    
1769        LATER: After change 22 below (new libtool files), the configure script
1770        seems to know about icc (and also ecc). Therefore, I have commented out
1771        this hack in configure.in.
1772    
1773     7. Added support for pkg-config (2 patches were sent in).
1774    
1775     8. Negated POSIX character classes that used a combination of internal tables
1776        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1777        [[:^ascii]]. Typically, they would match almost any characters. The other
1778        POSIX classes were not broken in this way.
1779    
1780     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1781        to find the match, as PCRE was deluded into thinking that the match had to
1782        start at the start point or following a newline. The same bug applied to
1783        patterns with negative forward assertions or any backward assertions
1784        preceding ".*" at the start, unless the pattern required a fixed first
1785        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1786    
1787    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1788        starting at the last subject character, bytes beyond the end of the subject
1789        string were read.
1790    
1791    11. Renamed the variable "class" as "classbits" to make life easier for C++
1792        users. (Previously there was a macro definition, but it apparently wasn't
1793        enough.)
1794    
1795    12. Added the new field "tables" to the extra data so that tables can be passed
1796        in at exec time, or the internal tables can be re-selected. This allows
1797        a compiled regex to be saved and re-used at a later time by a different
1798        program that might have everything at different addresses.
1799    
1800    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1801        -R library as well as a -L library.
1802    
1803    14. The debugging options of pcretest (-d on the command line or D on a
1804        pattern) showed incorrect output for anything following an extended class
1805        that contained multibyte characters and which was followed by a quantifier.
1806    
1807    15. Added optional support for general category Unicode character properties
1808        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1809        support. It adds about 90K to the size of the library. The meanings of the
1810        inbuilt class escapes such as \d and \s have NOT been changed.
1811    
1812    16. Updated pcredemo.c to include calls to free() to release the memory for the
1813        compiled pattern.
1814    
1815    17. The generated file chartables.c was being created in the source directory
1816        instead of in the building directory. This caused the build to fail if the
1817        source directory was different from the building directory, and was
1818        read-only.
1819    
1820    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1821        file. No doubt somebody will tell me if they don't make sense... Also added
1822        Dan Mooney's comments about building on OpenVMS.
1823    
1824    19. Added support for partial matching via the PCRE_PARTIAL option for
1825        pcre_exec() and the \P data escape in pcretest.
1826    
1827    20. Extended pcretest with 3 new pattern features:
1828    
1829        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1830              write the compiled pattern to the file whose name is "rest-of-line".
1831              This is a straight binary dump of the data, with the saved pointer to
1832              the character tables forced to be NULL. The study data, if any, is
1833              written too. After writing, pcretest reads a new pattern.
1834    
1835        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1836              compiled pattern from the given file. There must not be any
1837              occurrences of "<" in the file name (pretty unlikely); if there are,
1838              pcretest will instead treat the initial "<" as a pattern delimiter.
1839              After reading in the pattern, pcretest goes on to read data lines as
1840              usual.
1841    
1842        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1843              and 16-bit fields in a compiled pattern, to simulate a pattern that
1844              was compiled on a host of opposite endianness.
1845    
1846    21. The pcre-exec() function can now cope with patterns that were compiled on
1847        hosts of opposite endianness, with this restriction:
1848    
1849          As for any compiled expression that is saved and used later, the tables
1850          pointer field cannot be preserved; the extra_data field in the arguments
1851          to pcre_exec() should be used to pass in a tables address if a value
1852          other than the default internal tables were used at compile time.
1853    
1854    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1855        now diagnosed as an error. Previously, most of the time, a negative number
1856        would have been treated as zero, but if in addition "ovector" was passed as
1857        NULL, a crash could occur.
1858    
1859    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1860        new versions from the libtool 1.5 distribution (the last one is a copy of
1861        a file called libtool.m4). This seems to have fixed the need to patch
1862        "configure" to support Darwin 1.3 (which I used to do). However, I still
1863        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1864        workstation).
1865    
1866    24. Changed the PCRE licence to be the more standard "BSD" licence.
1867    
1868    
1869    Version 4.5 01-Dec-03
1870    ---------------------
1871    
1872     1. There has been some re-arrangement of the code for the match() function so
1873        that it can be compiled in a version that does not call itself recursively.
1874        Instead, it keeps those local variables that need separate instances for
1875        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1876        needs to "recurse". Keeping track of where control must go is done by means
1877        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1878        hide most of the details from the main code, and operates only if
1879        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1880        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1881        operating.
1882    
1883        To make it easier for callers to provide specially tailored get/free
1884        functions for this usage, two new functions, pcre_stack_malloc, and
1885        pcre_stack_free, are used. They are always called in strict stacking order,
1886        and the size of block requested is always the same.
1887    
1888        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1889        PCRE has been compiled to use the stack or the heap for recursion. The
1890        -C option of pcretest uses this to show which version is compiled.
1891    
1892        A new data escape \S, is added to pcretest; it causes the amounts of store
1893        obtained and freed by both kinds of malloc/free at match time to be added
1894        to the output.
1895    
1896     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1897        what's available on my current Linux desktop machine.
1898    
1899     3. When matching a UTF-8 string, the test for a valid string at the start has
1900        been extended. If start_offset is not zero, PCRE now checks that it points
1901        to a byte that is the start of a UTF-8 character. If not, it returns
1902        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1903        this is necessary because there may be backward assertions in the pattern.
1904        When matching the same subject several times, it may save resources to use
1905        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1906    
1907     4. The code for checking the validity of UTF-8 strings has been tightened so
1908        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1909        containing "overlong sequences".
1910    
1911     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1912        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1913        should have been "&", but it just so happened that all the cases this let
1914        through by mistake were picked up later in the function.
1915    
1916     6. I had used a variable called "isblank" - this is a C99 function, causing
1917        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1918    
1919     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1920        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1921        so the version is shown; (c) stop "make test" echoing "./RunTest".
1922    
1923     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1924    
1925     9. The prototype for memmove() for systems that don't have it was using
1926        size_t, but the inclusion of the header that defines size_t was later. I've
1927        moved the #includes for the C headers earlier to avoid this.
1928    
1929    10. Added some adjustments to the code to make it easier to compiler on certain
1930        special systems:
1931    
1932          (a) Some "const" qualifiers were missing.
1933          (b) Added the macro EXPORT before all exported functions; by default this
1934              is defined to be empty.
1935          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1936              that it reads its output file name as an argument instead of writing
1937              to the standard output and assuming this can be redirected.
1938    
1939    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1940        class containing characters with values greater than 255, PCRE compilation
1941        went into a loop.
1942    
1943    12. A recursive reference to a subpattern that was within another subpattern
1944        that had a minimum quantifier of zero caused PCRE to crash. For example,
1945        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1946        recursion. If the recursively-called subpattern itself had a zero repeat,
1947        that was OK.
1948    
1949    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1950        buffer into which it was copied (for escape processing) was still set at
1951        1024, so long lines caused crashes.
1952    
1953    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1954        "internal error: code overflow...". This applied to any character class
1955        that was followed by a possessive quantifier.
1956    
1957    15. Modified the Makefile to add libpcre.la as a prerequisite for
1958        libpcreposix.la because I was told this is needed for a parallel build to
1959        work.
1960    
1961    16. If a pattern that contained .* following optional items at the start was
1962        studied, the wrong optimizing data was generated, leading to matching
1963        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1964        matching string must start with a or b or c. The correct conclusion for
1965        this pattern is that a match can start with any character.
1966    
1967    
1968    Version 4.4 13-Aug-03
1969    ---------------------
1970    
1971     1. In UTF-8 mode, a character class containing characters with values between
1972        127 and 255 was not handled correctly if the compiled pattern was studied.
1973        In fixing this, I have also improved the studying algorithm for such
1974        classes (slightly).
1975    
1976     2. Three internal functions had redundant arguments passed to them. Removal
1977        might give a very teeny performance improvement.
1978    
1979     3. Documentation bug: the value of the capture_top field in a callout is *one
1980        more than* the number of the hightest numbered captured substring.
1981    
1982     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1983        in incorrectly linking with a previously installed version. They now link
1984        explicitly with libpcre.la.
1985    
1986     5. configure.in no longer needs to recognize Cygwin specially.
1987    
1988     6. A problem in pcre.in for Windows platforms is fixed.
1989    
1990     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1991        pcretest, it used to include the size of the study block as part of its
1992        output. Unfortunately, the structure contains a field that has a different
1993        size on different hardware architectures. This meant that the tests that
1994        showed this size failed. As the block is currently always of a fixed size,
1995        this information isn't actually particularly useful in pcretest output, so
1996        I have just removed it.
1997    
1998     8. Three pre-processor statements accidentally did not start in column 1.
1999        Sadly, there are *still* compilers around that complain, even though
2000        standard C has not required this for well over a decade. Sigh.
2001    
2002     9. In pcretest, the code for checking callouts passed small integers in the
2003        callout_data field, which is a void * field. However, some picky compilers
2004        complained about the casts involved for this on 64-bit systems. Now
2005        pcretest passes the address of the small integer instead, which should get
2006        rid of the warnings.
2007    
2008    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
2009        both compile and run time, and gives an error if an invalid UTF-8 sequence
2010        is found. There is a option for disabling this check in cases where the
2011        string is known to be correct and/or the maximum performance is wanted.
2012    
2013    11. In response to a bug report, I changed one line in Makefile.in from
2014    
2015            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
2016        to
2017            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
2018    
2019        to look similar to other lines, but I have no way of telling whether this
2020        is the right thing to do, as I do not use Windows. No doubt I'll get told
2021        if it's wrong...
2022    
2023    
2024    Version 4.3 21-May-03
2025    ---------------------
2026    
2027    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
2028       Makefile.
2029    
2030    2. Some refactoring to improve the quality of the code:
2031    
2032       (i)   The utf8_table... variables are now declared "const".
2033    
2034       (ii)  The code for \cx, which used the "case flipping" table to upper case
2035             lower case letters, now just substracts 32. This is ASCII-specific,
2036             but the whole concept of \cx is ASCII-specific, so it seems
2037             reasonable.
2038    
2039       (iii) PCRE was using its character types table to recognize decimal and
2040             hexadecimal digits in the pattern. This is silly, because it handles
2041             only 0-9, a-f, and A-F, but the character types table is locale-
2042             specific, which means strange things might happen. A private
2043             table is now used for this - though it costs 256 bytes, a table is
2044             much faster than multiple explicit tests. Of course, the standard
2045             character types table is still used for matching digits in subject
2046             strings against \d.
2047    
2048       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
2049             ending in _t are). So I've renamed it as ESC_tee.
2050    
2051    3. The first argument for regexec() in the POSIX wrapper should have been
2052       defined as "const".
2053    
2054    4. Changed pcretest to use malloc() for its buffers so that they can be
2055       Electric Fenced for debugging.
2056    
2057    5. There were several places in the code where, in UTF-8 mode, PCRE would try
2058       to read one or more bytes before the start of the subject string. Often this
2059       had no effect on PCRE's behaviour, but in some circumstances it could
2060       provoke a segmentation fault.
2061    
2062    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
2063       to try to read one or more bytes before the start of the subject string.
2064    
2065    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
2066       UTF-8 support could misbehave in various ways if the subject string
2067       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
2068       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
2069       back over UTF-8 characters.)
2070    
2071    
2072    Version 4.2 14-Apr-03
2073    ---------------------
2074    
2075    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
2076    
2077    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2078         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2079         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2080         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2081         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2082           and BUILD_EXEEXT
2083         Note: automatic setting of the BUILD variables is not yet working
2084         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2085           compile-time but not at link-time
2086         [LINK]: use for linking executables only
2087         make different versions for Windows and non-Windows
2088         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2089           libraries
2090         [LINK_FOR_BUILD]: new variable
2091         [OBJEXT]: use throughout
2092         [EXEEXT]: use throughout
2093         <winshared>: new target
2094         <wininstall>: new target
2095         <dftables.o>: use native compiler
2096         <dftables>: use native linker
2097         <install>: handle Windows platform correctly
2098         <clean>: ditto
2099         <check>: ditto
2100         copy DLL to top builddir before testing
2101    
2102       As part of these changes, -no-undefined was removed again. This was reported
2103       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2104       in any case.
2105    
2106    3. Some tidies to get rid of compiler warnings:
2107    
2108       . In the match_data structure, match_limit was an unsigned long int, whereas
2109         match_call_count was an int. I've made them both unsigned long ints.
2110    
2111       . In pcretest the fact that a const uschar * doesn't automatically cast to
2112         a void * provoked a warning.
2113    
2114       . Turning on some more compiler warnings threw up some "shadow" variables
2115         and a few more missing casts.
2116    
2117    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2118       option, a class that contained a single character with a value between 128
2119       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2120    
2121    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2122       option, a class that contained several characters, but with at least one
2123       whose value was between 128 and 255 caused PCRE to crash.
2124    
2125    
2126    Version 4.1 12-Mar-03
2127    ---------------------
2128    
2129    1. Compiling with gcc -pedantic found a couple of places where casts were
2130    needed, and a string in dftables.c that was longer than standard compilers are
2131    required to support.
2132    
2133    2. Compiling with Sun's compiler found a few more places where the code could
2134    be tidied up in order to avoid warnings.
2135    
2136    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2137    first of these names is deprecated in the latest Autoconf in favour of the name
2138    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2139    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2140    analogy I have changed it to CFLAGS_FOR_BUILD.
2141    
2142    4. Added -no-undefined to the linking command in the Makefile, because this is
2143    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2144    linking step for the pcreposix library.
2145    
2146    5. PCRE was failing to diagnose the case of two named groups with the same
2147    name.
2148    
2149    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2150    literal character that is needed in the subject for a match, and scans along to
2151    ensure that it is present before embarking on the full matching process. This
2152    saves time in cases of nested unlimited repeats that are never going to match.
2153    Problem: the scan can take a lot of time if the subject is very long (e.g.
2154    megabytes), thus penalizing straightforward matches. It is now done only if the
2155    amount of subject to be scanned is less than 1000 bytes.
2156    
2157    7. A lesser problem with the same optimization is that it was recording the
2158    first character of an anchored pattern as "needed", thus provoking a search
2159    right along the subject, even when the first match of the pattern was going to
2160    fail. The "needed" character is now not set for anchored patterns, unless it
2161    follows something in the pattern that is of non-fixed length. Thus, it still
2162    fulfils its original purpose of finding quick non-matches in cases of nested
2163    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2164    
2165    
2166    Version 4.0 17-Feb-03
2167    ---------------------
2168    
2169    1. If a comment in an extended regex that started immediately after a meta-item
2170    extended to the end of string, PCRE compiled incorrect data. This could lead to
2171    all kinds of weird effects. Example: /#/ was bad; /()#/ was bad; /a#/ was not.
2172    
2173    2. Moved to autoconf 2.53 and libtool 1.4.2.
2174    
2175    3. Perl 5.8 no longer needs "use utf8" for doing UTF-8 things. Consequently,
2176    the special perltest8 script is no longer needed - all the tests can be run
2177    from a single perltest script.
2178    
2179    4. From 5.004, Perl has not included the VT character (0x0b) in the set defined
2180    by \s. It has now been removed in PCRE. This means it isn't recognized as
2181    whitespace in /x regexes too, which is the same as Perl. Note that the POSIX
2182    class [:space:] *does* include VT, thereby creating a mess.
2183    
2184    5. Added the class [:blank:] (a GNU extension from Perl 5.8) to match only
2185    space and tab.
2186    
2187    6. Perl 5.005 was a long time ago. It's time to amalgamate the tests that use
2188    its new features into the main test script, reducing the number of scripts.
2189    
2190    7. Perl 5.8 has changed the meaning of patterns like /a(?i)b/. Earlier versions
2191    were backward compatible, and made the (?i) apply to the whole pattern, as if
2192    /i were given. Now it behaves more logically, and applies the option setting
2193    only to what follows. PCRE has been changed to follow suit. However, if it
2194    finds options settings right at the start of the pattern, it extracts them into
2195    the global options, as before. Thus, they show up in the info data.
2196    
2197    8. Added support for the \Q...\E escape sequence. Characters in between are
2198    treated as literals. This is slightly different from Perl in that $ and @ are
2199    also handled as literals inside the quotes. In Perl, they will cause variable
2200    interpolation. Note the following examples:
2201    
2202        Pattern            PCRE matches      Perl matches
2203    
2204        \Qabc$xyz\E        abc$xyz           abc followed by the contents of $xyz
2205        \Qabc\$xyz\E       abc\$xyz          abc\$xyz
2206        \Qabc\E\$\Qxyz\E   abc$xyz           abc$xyz
2207    
2208    For compatibility with Perl, \Q...\E sequences are recognized inside character
2209    classes as well as outside them.
2210    
2211    9. Re-organized 3 code statements in pcretest to avoid "overflow in
2212    floating-point constant arithmetic" warnings from a Microsoft compiler. Added a
2213    (size_t) cast to one statement in pcretest and one in pcreposix to avoid
2214    signed/unsigned warnings.
2215    
2216    10. SunOS4 doesn't have strtoul(). This was used only for unpicking the -o
2217    option for pcretest, so I've replaced it by a simple function that does just
2218    that job.
2219    
2220    11. pcregrep was ending with code 0 instead of 2 for the commands "pcregrep" or
2221    "pcregrep -".
2222    
2223    12. Added "possessive quantifiers" ?+, *+, ++, and {,}+ which come from Sun's
2224    Java package. This provides some syntactic sugar for simple cases of what my
2225    documentation calls "once-only subpatterns". A pattern such as x*+ is the same
2226    as (?>x*). In other words, if what is inside (?>...) is just a single repeated
2227    item, you can use this simplified notation. Note that only makes sense with
2228    greedy quantifiers. Consequently, the use of the possessive quantifier forces
2229    greediness, whatever the setting of the PCRE_UNGREEDY option.
2230    
2231    13. A change of greediness default within a pattern was not taking effect at
2232    the current level for patterns like /(b+(?U)a+)/. It did apply to parenthesized
2233    subpatterns that followed. Patterns like /b+(?U)a+/ worked because the option
2234    was abstracted outside.
2235    
2236    14. PCRE now supports the \G assertion. It is true when the current matching
2237    position is at the start point of the match. This differs from \A when the
2238    starting offset is non-zero. Used with the /g option of pcretest (or similar
2239    code), it works in the same way as it does for Perl's /g option. If all
2240    alternatives of a regex begin with \G, the expression is anchored to the start
2241    match position, and the "anchored" flag is set in the compiled expression.
2242    
2243    15. Some bugs concerning the handling of certain option changes within patterns
2244    have been fixed. These applied to options other than (?ims). For example,
2245    "a(?x: b c )d" did not match "XabcdY" but did match "Xa b c dY". It should have
2246    been the other way round. Some of this was related to change 7 above.
2247    
2248    16. PCRE now gives errors for /[.x.]/ and /[=x=]/ as unsupported POSIX
2249    features, as Perl does. Previously, PCRE gave the warnings only for /[[.x.]]/
2250    and /[[=x=]]/. PCRE now also gives an error for /[:name:]/ because it supports
2251    POSIX classes only within a class (e.g. /[[:alpha:]]/).
2252    
2253    17. Added support for Perl's \C escape. This matches one byte, even in UTF8
2254    mode. Unlike ".", it always matches newline, whatever the setting of
2255    PCRE_DOTALL. However, PCRE does not permit \C to appear in lookbehind
2256    assertions. Perl allows it, but it doesn't (in general) work because it can't
2257    calculate the length of the lookbehind. At least, that's the case for Perl
2258    5.8.0 - I've been told they are going to document that it doesn't work in
2259    future.
2260    
2261    18. Added an error diagnosis for escapes that PCRE does not support: these are
2262    \L, \l, \N, \P, \p, \U, \u, and \X.
2263    
2264    19. Although correctly diagnosing a missing ']' in a character class, PCRE was
2265    reading past the end of the pattern in cases such as /[abcd/.
2266    
2267    20. PCRE was getting more memory than necessary for patterns with classes that
2268    contained both POSIX named classes and other characters, e.g. /[[:space:]abc/.
2269    
2270    21. Added some code, conditional on #ifdef VPCOMPAT, to make life easier for
2271    compiling PCRE for use with Virtual Pascal.
2272    
2273    22. Small fix to the Makefile to make it work properly if the build is done
2274    outside the source tree.
2275    
2276    23. Added a new extension: a condition to go with recursion. If a conditional
2277    subpattern starts with (?(R) the "true" branch is used if recursion has
2278    happened, whereas the "false" branch is used only at the top level.
2279    
2280    24. When there was a very long string of literal characters (over 255 bytes
2281    without UTF support, over 250 bytes with UTF support), the computation of how
2282    much memory was required could be incorrect, leading to segfaults or other
2283    strange effects.
2284    
2285    25. PCRE was incorrectly assuming anchoring (either to start of subject or to
2286    start of line for a non-DOTALL pattern) when a pattern started with (.*) and
2287    there was a subsequent back reference to those brackets. This meant that, for
2288    example, /(.*)\d+\1/ failed to match "abc123bc". Unfortunately, it isn't
2289    possible to check for precisely this case. All we can do is abandon the
2290    optimization if .* occurs inside capturing brackets when there are any back
2291    references whatsoever. (See below for a better fix that came later.)
2292    
2293    26. The handling of the optimization for finding the first character of a
2294    non-anchored pattern, and for finding a character that is required later in the
2295    match were failing in some cases. This didn't break the matching; it just
2296    failed to optimize when it could. The way this is done has been re-implemented.
2297    
2298    27. Fixed typo in error message for invalid (?R item (it said "(?p").
2299    
2300    28. Added a new feature that provides some of the functionality that Perl
2301    provides with (?{...}). The facility is termed a "callout". The way it is done
2302    in PCRE is for the caller to provide an optional function, by setting
2303    pcre_callout to its entry point. Like pcre_malloc and pcre_free, this is a
2304    global variable. By default it is unset, which disables all calling out. To get
2305    the function called, the regex must include (?C) at appropriate points. This
2306    is, in fact, equivalent to (?C0), and any number <= 255 may be given with (?C).
2307    This provides a means of identifying different callout points. When PCRE
2308    reaches such a point in the regex, if pcre_callout has been set, the external
2309    function is called. It is provided with data in a structure called
2310    pcre_callout_block, which is defined in pcre.h. If the function returns 0,
2311    matching continues; if it returns a non-zero value, the match at the current
2312    point fails. However, backtracking will occur if possible. [This was changed
2313    later and other features added - see item 49 below.]
2314    
2315    29. pcretest is upgraded to test the callout functionality. It provides a
2316    callout function that displays information. By default, it shows the start of
2317    the match and the current position in the text. There are some new data escapes
2318    to vary what happens:
2319    
2320        \C+         in addition, show current contents of captured substrings
2321        \C-         do not supply a callout function
2322        \C!n        return 1 when callout number n is reached
2323        \C!n!m      return 1 when callout number n is reached for the mth time
2324    
2325    30. If pcregrep was called with the -l option and just a single file name, it
2326    output "<stdin>" if a match was found, instead of the file name.
2327    
2328    31. Improve the efficiency of the POSIX API to PCRE. If the number of capturing
2329    slots is less than POSIX_MALLOC_THRESHOLD, use a block on the stack to pass to
2330    pcre_exec(). This saves a malloc/free per call. The default value of
2331    POSIX_MALLOC_THRESHOLD is 10; it can be changed by --with-posix-malloc-threshold
2332    when configuring.
2333    
2334    32. The default maximum size of a compiled pattern is 64K. There have been a
2335    few cases of people hitting this limit. The code now uses macros to handle the
2336    storing of links as offsets within the compiled pattern. It defaults to 2-byte
2337    links, but this can be changed to 3 or 4 bytes by --with-link-size when
2338    configuring. Tests 2 and 5 work only with 2-byte links because they output
2339    debugging information about compiled patterns.
2340    
2341    33. Internal code re-arrangements:
2342    
2343    (a) Moved the debugging function for printing out a compiled regex into
2344        its own source file (printint.c) and used #include to pull it into
2345        pcretest.c and, when DEBUG is defined, into pcre.c, instead of having two
2346        separate copies.
2347    
2348    (b) Defined the list of op-code names for debugging as a macro in
2349        internal.h so that it is next to the definition of the opcodes.
2350    
2351    (c) Defined a table of op-code lengths for simpler skipping along compiled
2352        code. This is again a macro in internal.h so that it is next to the
2353        definition of the opcodes.
2354    
2355    34. Added support for recursive calls to individual subpatterns, along the
2356    lines of Robin Houston's patch (but implemented somewhat differently).
2357    
2358    35. Further mods to the Makefile to help Win32. Also, added code to pcregrep to
2359    allow it to read and process whole directories in Win32. This code was
2360    contributed by Lionel Fourquaux; it has not been tested by me.
2361    
2362    36. Added support for named subpatterns. The Python syntax (?P<name>...) is
2363    used to name a group. Names consist of alphanumerics and underscores, and must
2364    be unique. Back references use the syntax (?P=name) and recursive calls use
2365    (?P>name) which is a PCRE extension to the Python extension. Groups still have
2366    numbers. The function pcre_fullinfo() can be used after compilation to extract
2367    a name/number map. There are three relevant calls:
2368    
2369      PCRE_INFO_NAMEENTRYSIZE        yields the size of each entry in the map
2370      PCRE_INFO_NAMECOUNT            yields the number of entries
2371      PCRE_INFO_NAMETABLE            yields a pointer to the map.
2372    
2373    The map is a vector of fixed-size entries. The size of each entry depends on
2374    the length of the longest name used. The first two bytes of each entry are the
2375    group number, most significant byte first. There follows the corresponding
2376    name, zero terminated. The names are in alphabetical order.
2377    
2378    37. Make the maximum literal string in the compiled code 250 for the non-UTF-8
2379    case instead of 255. Making it the same both with and without UTF-8 support
2380    means that the same test output works with both.
2381    
2382    38. There was a case of malloc(0) in the POSIX testing code in pcretest. Avoid
2383    calling malloc() with a zero argument.
2384    
2385    39. Change 25 above had to resort to a heavy-handed test for the .* anchoring
2386    optimization. I've improved things by keeping a bitmap of backreferences with
2387    numbers 1-31 so that if .* occurs inside capturing brackets that are not in
2388    fact referenced, the optimization can be applied. It is unlikely that a
2389    relevant occurrence of .* (i.e. one which might indicate anchoring or forcing
2390    the match to follow \n) will appear inside brackets with a number greater than
2391    31, but if it does, any back reference > 31 suppresses the optimization.
2392    
2393    40. Added a new compile-time option PCRE_NO_AUTO_CAPTURE. This has the effect
2394    of disabling numbered capturing parentheses. Any opening parenthesis that is
2395    not followed by ? behaves as if it were followed by ?: but named parentheses
2396    can still be used for capturing (and they will acquire numbers in the usual
2397    way).
2398    
2399    41. Redesigned the return codes from the match() function into yes/no/error so
2400    that errors can be passed back from deep inside the nested calls. A malloc
2401    failure while inside a recursive subpattern call now causes the
2402    PCRE_ERROR_NOMEMORY return instead of quietly going wrong.
2403    
2404    42. It is now possible to set a limit on the number of times the match()
2405    function is called in a call to pcre_exec(). This facility makes it possible to
2406    limit the amount of recursion and backtracking, though not in a directly
2407    obvious way, because the match() function is used in a number of different
2408    circumstances. The count starts from zero for each position in the subject
2409    string (for non-anchored patterns). The default limit is, for compatibility, a
2410    large number, namely 10 000 000. You can change this in two ways:
2411    
2412    (a) When configuring PCRE before making, you can use --with-match-limit=n
2413        to set a default value for the compiled library.
2414    
2415    (b) For each call to pcre_exec(), you can pass a pcre_extra block in which
2416        a different value is set. See 45 below.
2417    
2418    If the limit is exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
2419    
2420    43. Added a new function pcre_config(int, void *) to enable run-time extraction
2421    of things that can be changed at compile time. The first argument specifies
2422    what is wanted and the second points to where the information is to be placed.
2423    The current list of available information is:
2424    
2425      PCRE_CONFIG_UTF8
2426    
2427    The output is an integer that is set to one if UTF-8 support is available;
2428    otherwise it is set to zero.
2429    
2430      PCRE_CONFIG_NEWLINE
2431    
2432    The output is an integer that it set to the value of the code that is used for
2433    newline. It is either LF (10) or CR (13).
2434    
2435      PCRE_CONFIG_LINK_SIZE
2436    
2437    The output is an integer that contains the number of bytes used for internal
2438    linkage in compiled expressions. The value is 2, 3, or 4. See item 32 above.
2439    
2440      PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
2441    
2442    The output is an integer that contains the threshold above which the POSIX
2443    interface uses malloc() for output vectors. See item 31 above.
2444    
2445      PCRE_CONFIG_MATCH_LIMIT
2446    
2447    The output is an unsigned integer that contains the default limit of the number
2448    of match() calls in a pcre_exec() execution. See 42 above.
2449    
2450    44. pcretest has been upgraded by the addition of the -C option. This causes it
2451    to extract all the available output from the new pcre_config() function, and to
2452    output it. The program then exits immediately.
2453    
2454    45. A need has arisen to pass over additional data with calls to pcre_exec() in
2455    order to support additional features. One way would have been to define
2456    pcre_exec2() (for example) with extra arguments, but this would not have been
2457    extensible, and would also have required all calls to the original function to
2458    be mapped to the new one. Instead, I have chosen to extend the mechanism that
2459    is used for passing in "extra" data from pcre_study().
2460    
2461    The pcre_extra structure is now exposed and defined in pcre.h. It currently
2462    contains the following fields:
2463    
2464      flags         a bitmap indicating which of the following fields are set
2465      study_data    opaque data from pcre_study()
2466      match_limit   a way of specifying a limit on match() calls for a specific
2467                      call to pcre_exec()
2468      callout_data  data for callouts (see 49 below)
2469    
2470    The flag bits are also defined in pcre.h, and are
2471    
2472      PCRE_EXTRA_STUDY_DATA
2473      PCRE_EXTRA_MATCH_LIMIT
2474      PCRE_EXTRA_CALLOUT_DATA
2475    
2476    The pcre_study() function now returns one of these new pcre_extra blocks, with
2477    the actual study data pointed to by the study_data field, and the
2478    PCRE_EXTRA_STUDY_DATA flag set. This can be passed directly to pcre_exec() as
2479    before. That is, this change is entirely upwards-compatible and requires no
2480    change to existing code.
2481    
2482    If you want to pass in additional data to pcre_exec(), you can either place it
2483    in a pcre_extra block provided by pcre_study(), or create your own pcre_extra
2484    block.
2485    
2486    46. pcretest has been extended to test the PCRE_EXTRA_MATCH_LIMIT feature. If a
2487    data string contains the escape sequence \M, pcretest calls pcre_exec() several
2488    times with different match limits, until it finds the minimum value needed for
2489    pcre_exec() to complete. The value is then output. This can be instructive; for
2490    most simple matches the number is quite small, but for pathological cases it
2491    gets very large very quickly.
2492    
2493    47. There's a new option for pcre_fullinfo() called PCRE_INFO_STUDYSIZE. It
2494    returns the size of the data block pointed to by the study_data field in a
2495    pcre_extra block, that is, the value that was passed as the argument to
2496    pcre_malloc() when PCRE was getting memory in which to place the information
2497    created by pcre_study(). The fourth argument should point to a size_t variable.
2498    pcretest has been extended so that this information is shown after a successful
2499    pcre_study() call when information about the compiled regex is being displayed.
2500    
2501    48. Cosmetic change to Makefile: there's no need to have / after $(DESTDIR)
2502    because what follows is always an absolute path. (Later: it turns out that this
2503    is more than cosmetic for MinGW, because it doesn't like empty path
2504    components.)
2505    
2506    49. Some changes have been made to the callout feature (see 28 above):
2507    
2508    (i)  A callout function now has three choices for what it returns:
2509    
2510           0  =>  success, carry on matching
2511         > 0  =>  failure at this point, but backtrack if possible
2512         < 0  =>  serious error, return this value from pcre_exec()
2513    
2514         Negative values should normally be chosen from the set of PCRE_ERROR_xxx
2515         values. In particular, returning PCRE_ERROR_NOMATCH forces a standard
2516         "match failed" error. The error number PCRE_ERROR_CALLOUT is reserved for
2517         use by callout functions. It will never be used by PCRE itself.
2518    
2519    (ii) The pcre_extra structure (see 45 above) has a void * field called
2520         callout_data, with corresponding flag bit PCRE_EXTRA_CALLOUT_DATA. The
2521         pcre_callout_block structure has a field of the same name. The contents of
2522         the field passed in the pcre_extra structure are passed to the callout
2523         function in the corresponding field in the callout block. This makes it
2524         easier to use the same callout-containing regex from multiple threads. For
2525         testing, the pcretest program has a new data escape
2526    
2527           \C*n        pass the number n (may be negative) as callout_data
2528    
2529         If the callout function in pcretest receives a non-zero value as
2530         callout_data, it returns that value.
2531    
2532    50. Makefile wasn't handling CFLAGS properly when compiling dftables. Also,
2533    there were some redundant $(CFLAGS) in commands that are now specified as
2534    $(LINK), which already includes $(CFLAGS).
2535    
2536    51. Extensions to UTF-8 support are listed below. These all apply when (a) PCRE
2537    has been compiled with UTF-8 support *and* pcre_compile() has been compiled
2538    with the PCRE_UTF8 flag. Patterns that are compiled without that flag assume
2539    one-byte characters throughout. Note that case-insensitive matching applies
2540    only to characters whose values are less than 256. PCRE doesn't support the
2541    notion of cases for higher-valued characters.
2542    
2543    (i)   A character class whose characters are all within 0-255 is handled as
2544          a bit map, and the map is inverted for negative classes. Previously, a
2545          character > 255 always failed to match such a class; however it should
2546          match if the class was a negative one (e.g. [^ab]). This has been fixed.
2547    
2548    (ii)  A negated character class with a single character < 255 is coded as
2549          "not this character" (OP_NOT). This wasn't working properly when the test
2550          character was multibyte, either singly or repeated.
2551    
2552    (iii) Repeats of multibyte characters are now handled correctly in UTF-8
2553          mode, for example: \x{100}{2,3}.
2554    
2555    (iv)  The character escapes \b, \B, \d, \D, \s, \S, \w, and \W (either
2556          singly or repeated) now correctly test multibyte characters. However,
2557          PCRE doesn't recognize any characters with values greater than 255 as
2558          digits, spaces, or word characters. Such characters always match \D, \S,
2559          and \W, and never match \d, \s, or \w.
2560    
2561    (v)   Classes may now contain characters and character ranges with values
2562          greater than 255. For example: [ab\x{100}-\x{400}].
2563    
2564    (vi)  pcregrep now has a --utf-8 option (synonym -u) which makes it call
2565          PCRE in UTF-8 mode.
2566    
2567    52. The info request value PCRE_INFO_FIRSTCHAR has been renamed
2568    PCRE_INFO_FIRSTBYTE because it is a byte value. However, the old name is
2569    retained for backwards compatibility. (Note that LASTLITERAL is also a byte
2570    value.)
2571    
2572    53. The single man page has become too large. I have therefore split it up into
2573    a number of separate man pages. These also give rise to individual HTML pages;
2574    these are now put in a separate directory, and there is an index.html page that
2575    lists them all. Some hyperlinking between the pages has been installed.
2576    
2577    54. Added convenience functions for handling named capturing parentheses.
2578    
2579    55. Unknown escapes inside character classes (e.g. [\M]) and escapes that
2580    aren't interpreted therein (e.g. [\C]) are literals in Perl. This is now also
2581    true in PCRE, except when the PCRE_EXTENDED option is set, in which case they
2582    are faulted.
2583    
2584    56. Introduced HOST_CC and HOST_CFLAGS which can be set in the environment when
2585    calling configure. These values are used when compiling the dftables.c program
2586    which is run to generate the source of the default character tables. They
2587    default to the values of CC and CFLAGS. If you are cross-compiling PCRE,
2588    you will need to set these values.
2589    
2590    57. Updated the building process for Windows DLL, as provided by Fred Cox.
2591    
2592    
2593    Version 3.9 02-Jan-02
2594    ---------------------
2595    
2596    1. A bit of extraneous text had somehow crept into the pcregrep documentation.
2597    
2598    2. If --disable-static was given, the building process failed when trying to
2599    build pcretest and pcregrep. (For some reason it was using libtool to compile
2600    them, which is not right, as they aren't part of the library.)
2601    
2602    
2603    Version 3.8 18-Dec-01
2604    ---------------------
2605    
2606    1. The experimental UTF-8 code was completely screwed up. It was packing the
2607    bytes in the wrong order. How dumb can you get?
2608    
2609    
2610    Version 3.7 29-Oct-01
2611    ---------------------
2612    
2613    1. In updating pcretest to check change 1 of version 3.6, I screwed up.
2614    This caused pcretest, when used on the test data, to segfault. Unfortunately,
2615    this didn't happen under Solaris 8, where I normally test things.
2616    
2617    2. The Makefile had to be changed to make it work on BSD systems, where 'make'
2618    doesn't seem to recognize that ./xxx and xxx are the same file. (This entry
2619    isn't in ChangeLog distributed with 3.7 because I forgot when I hastily made
2620    this fix an hour or so after the initial 3.7 release.)
2621    
2622    
2623    Version 3.6 23-Oct-01
2624    ---------------------
2625    
2626    1. Crashed with /(sens|respons)e and \1ibility/ and "sense and sensibility" if
2627    offsets passed as NULL with zero offset count.
2628    
2629    2. The config.guess and config.sub files had not been updated when I moved to
2630    the latest autoconf.
2631    
2632    
2633    Version 3.5 15-Aug-01
2634    ---------------------
2635    
2636    1. Added some missing #if !defined NOPOSIX conditionals in pcretest.c that
2637    had been forgotten.
2638    
2639    2. By using declared but undefined structures, we can avoid using "void"
2640    definitions in pcre.h while keeping the internal definitions of the structures
2641    private.
2642    
2643    3. The distribution is now built using autoconf 2.50 and libtool 1.4. From a
2644    user point of view, this means that both static and shared libraries are built
2645    by default, but this can be individually controlled. More of the work of
2646    handling this static/shared cases is now inside libtool instead of PCRE's make
2647    file.
2648    
2649    4. The pcretest utility is now installed along with pcregrep because it is
2650    useful for users (to test regexs) and by doing this, it automatically gets
2651    relinked by libtool. The documentation has been turned into a man page, so
2652    there are now .1, .txt, and .html versions in /doc.
2653    
2654    5. Upgrades to pcregrep:
2655       (i)   Added long-form option names like gnu grep.
2656       (ii)  Added --help to list all options with an explanatory phrase.
2657       (iii) Added -r, --recursive to recurse into sub-directories.
2658       (iv)  Added -f, --file to read patterns from a file.
2659    
2660    6. pcre_exec() was referring to its "code" argument before testing that
2661    argument for NULL (and giving an error if it was NULL).
2662    
2663    7. Upgraded Makefile.in to allow for compiling in a different directory from
2664    the source directory.
2665    
2666    8. Tiny buglet in pcretest: when pcre_fullinfo() was called to retrieve the
2667    options bits, the pointer it was passed was to an int instead of to an unsigned
2668    long int. This mattered only on 64-bit systems.
2669    
2670    9. Fixed typo (3.4/1) in pcre.h again. Sigh. I had changed pcre.h (which is
2671    generated) instead of pcre.in, which it its source. Also made the same change
2672    in several of the .c files.
2673    
2674    10. A new release of gcc defines printf() as a macro, which broke pcretest
2675    because it had an ifdef in the middle of a string argument for printf(). Fixed
2676    by using separate calls to printf().
2677    
2678    11. Added --enable-newline-is-cr and --enable-newline-is-lf to the configure
2679    script, to force use of CR or LF instead of \n in the source. On non-Unix
2680    systems, the value can be set in config.h.
2681    
2682    12. The limit of 200 on non-capturing parentheses is a _nesting_ limit, not an
2683    absolute limit. Changed the text of the error message to make this clear, and
2684    likewise updated the man page.
2685    
2686    13. The limit of 99 on the number of capturing subpatterns has been removed.
2687    The new limit is 65535, which I hope will not be a "real" limit.
2688    
2689    
2690    Version 3.4 22-Aug-00
2691    ---------------------
2692    
2693    1. Fixed typo in pcre.h: unsigned const char * changed to const unsigned char *.
2694    
2695    2. Diagnose condition (?(0) as an error instead of crashing on matching.
2696    
2697    
2698    Version 3.3 01-Aug-00
2699    ---------------------
2700    
2701    1. If an octal character was given, but the value was greater than \377, it
2702    was not getting masked to the least significant bits, as documented. This could
2703    lead to crashes in some systems.
2704    
2705    2. Perl 5.6 (if not earlier versions) accepts classes like [a-\d] and treats
2706    the hyphen as a literal. PCRE used to give an error; it now behaves like Perl.
2707    
2708    3. Added the functions pcre_free_substring() and pcre_free_substring_list().
2709    These just pass their arguments on to (pcre_free)(), but they are provided
2710    because some uses of PCRE bind it to non-C systems that can call its functions,
2711    but cannot call free() or pcre_free() directly.
2712    
2713    4. Add "make test" as a synonym for "make check". Corrected some comments in
2714    the Makefile.
2715    
2716    5. Add $(DESTDIR)/ in front of all the paths in the "install" target in the
2717    Makefile.
2718    
2719    6. Changed the name of pgrep to pcregrep, because Solaris has introduced a
2720    command called pgrep for grepping around the active processes.
2721    
2722    7. Added the beginnings of support for UTF-8 character strings.
2723    
2724    8. Arranged for the Makefile to pass over the settings of CC, CFLAGS, and
2725    RANLIB to ./ltconfig so that they are used by libtool. I think these are all
2726    the relevant ones. (AR is not passed because ./ltconfig does its own figuring
2727    out for the ar command.)
2728    
2729    
2730    Version 3.2 12-May-00
2731    ---------------------
2732    
2733    This is purely a bug fixing release.
2734    
2735    1. If the pattern /((Z)+|A)*/ was matched agained ZABCDEFG it matched Z instead
2736    of ZA. This was just one example of several cases that could provoke this bug,
2737    which was introduced by change 9 of version 2.00. The code for breaking
2738    infinite loops after an iteration that matches an empty string was't working
2739    correctly.
2740    
2741    2. The pcretest program was not imitating Perl correctly for the pattern /a*/g
2742    when matched against abbab (for example). After matching an empty string, it
2743    wasn't forcing anchoring when setting PCRE_NOTEMPTY for the next attempt; this
2744    caused it to match further down the string than it should.
2745    
2746    3. The code contained an inclusion of sys/types.h. It isn't clear why this
2747    was there because it doesn't seem to be needed, and it causes trouble on some
2748    systems, as it is not a Standard C header. It has been removed.
2749    
2750    4. Made 4 silly changes to the source to avoid stupid compiler warnings that
2751    were reported on the Macintosh. The changes were from
2752    
2753      while ((c = *(++ptr)) != 0 && c != '\n');
2754    to
2755      while ((c = *(++ptr)) != 0 && c != '\n') ;
2756    
2757    Totally extraordinary, but if that's what it takes...
2758    
2759    5. PCRE is being used in one environment where neither memmove() nor bcopy() is
2760    available. Added HAVE_BCOPY and an autoconf test for it; if neither
2761    HAVE_MEMMOVE nor HAVE_BCOPY is set, use a built-in emulation function which
2762    assumes the way PCRE uses memmove() (always moving upwards).
2763    
2764    6. PCRE is being used in one environment where strchr() is not available. There
2765    was only one use in pcre.c, and writing it out to avoid strchr() probably gives
2766    faster code anyway.
2767    
2768    
2769    Version 3.1 09-Feb-00
2770    ---------------------
2771    
2772    The only change in this release is the fixing of some bugs in Makefile.in for
2773    the "install" target:
2774    
2775    (1) It was failing to install pcreposix.h.
2776    
2777    (2) It was overwriting the pcre.3 man page with the pcreposix.3 man page.
2778    
2779    
2780    Version 3.0 01-Feb-00
2781    ---------------------
2782    
2783    1. Add support for the /+ modifier to perltest (to output $` like it does in
2784    pcretest).
2785    
2786    2. Add support for the /g modifier to perltest.
2787    
2788    3. Fix pcretest so that it behaves even more like Perl for /g when the pattern
2789    matches null strings.
2790    
2791    4. Fix perltest so that it doesn't do unwanted things when fed an empty
2792    pattern. Perl treats empty patterns specially - it reuses the most recent
2793    pattern, which is not what we want. Replace // by /(?#)/ in order to avoid this
2794    effect.
2795    
2796    5. The POSIX interface was broken in that it was just handing over the POSIX
2797    captured string vector to pcre_exec(), but (since release 2.00) PCRE has
2798    required a bigger vector, with some working space on the end. This means that
2799    the POSIX wrapper now has to get and free some memory, and copy the results.
2800    
2801    6. Added some simple autoconf support, placing the test data and the
2802    documentation in separate directories, re-organizing some of the
2803    information files, and making it build pcre-config (a GNU standard). Also added
2804    libtool support for building PCRE as a shared library, which is now the
2805    default.
2806    
2807    7. Got rid of the leading zero in the definition of PCRE_MINOR because 08 and
2808    09 are not valid octal constants. Single digits will be used for minor values
2809    less than 10.
2810    
2811    8. Defined REG_EXTENDED and REG_NOSUB as zero in the POSIX header, so that
2812    existing programs that set these in the POSIX interface can use PCRE without
2813    modification.
2814    
2815    9. Added a new function, pcre_fullinfo() with an extensible interface. It can
2816    return all that pcre_info() returns, plus additional data. The pcre_info()
2817    function is retained for compatibility, but is considered to be obsolete.
2818    
2819    10. Added experimental recursion feature (?R) to handle one common case that
2820    Perl 5.6 will be able to do with (?p{...}).
2821    
2822    11. Added support for POSIX character classes like [:alpha:], which Perl is
2823    adopting.
2824    
2825    
2826    Version 2.08 31-Aug-99
2827    ----------------------
2828    
2829    1. When startoffset was not zero and the pattern began with ".*", PCRE was not
2830    trying to match at the startoffset position, but instead was moving forward to
2831    the next newline as if a previous match had failed.
2832    
2833    2. pcretest was not making use of PCRE_NOTEMPTY when repeating for /g and /G,
2834    and could get into a loop if a null string was matched other than at the start
2835    of the subject.
2836    
2837    3. Added definitions of PCRE_MAJOR and PCRE_MINOR to pcre.h so the version can
2838    be distinguished at compile time, and for completeness also added PCRE_DATE.
2839    
2840    5. Added Paul Sokolovsky's minor changes to make it easy to compile a Win32 DLL
2841    in GnuWin32 environments.
2842    
2843    
2844    Version 2.07 29-Jul-99
2845    ----------------------
2846    
2847    1. The documentation is now supplied in plain text form and HTML as well as in
2848    the form of man page sources.
2849    
2850    2. C++ compilers don't like assigning (void *) values to other pointer types.
2851    In particular this affects malloc(). Although there is no problem in Standard
2852    C, I've put in casts to keep C++ compilers happy.
2853    
2854    3. Typo on pcretest.c; a cast of (unsigned char *) in the POSIX regexec() call
2855    should be (const char *).
2856    
2857    4. If NOPOSIX is defined, pcretest.c compiles without POSIX support. This may
2858    be useful for non-Unix systems who don't want to bother with the POSIX stuff.
2859    However, I haven't made this a standard facility. The documentation doesn't
2860    mention it, and the Makefile doesn't support it.
2861    
2862    5. The Makefile now contains an "install" target, with editable destinations at
2863    the top of the file. The pcretest program is not installed.
2864    
2865    6. pgrep -V now gives the PCRE version number and date.
2866    
2867    7. Fixed bug: a zero repetition after a literal string (e.g. /abcde{0}/) was
2868    causing the entire string to be ignored, instead of just the last character.
2869    
2870    8. If a pattern like /"([^\\"]+|\\.)*"/ is applied in the normal way to a
2871    non-matching string, it can take a very, very long time, even for strings of
2872    quite modest length, because of the nested recursion. PCRE now does better in
2873    some of these cases. It does this by remembering the last required literal
2874    character in the pattern, and pre-searching the subject to ensure it is present
2875    before running the real match. In other words, it applies a heuristic to detect
2876    some types of certain failure quickly, and in the above example, if presented
2877    with a string that has no trailing " it gives "no match" very quickly.
2878    
2879    9. A new runtime option PCRE_NOTEMPTY causes null string matches to be ignored;
2880    other alternatives are tried instead.
2881    
2882    
2883    Version 2.06 09-Jun-99
2884    ----------------------
2885    
2886    1. Change pcretest's output for amount of store used to show just the code
2887    space, because the remainder (the data block) varies in size between 32-bit and
2888    64-bit systems.
2889    
2890    2. Added an extra argument to pcre_exec() to supply an offset in the subject to
2891    start matching at. This allows lookbehinds to work when searching for multiple
2892    occurrences in a string.
2893    
2894    3. Added additional options to pcretest for testing multiple occurrences:
2895    
2896       /+   outputs the rest of the string that follows a match
2897       /g   loops for multiple occurrences, using the new startoffset argument
2898       /G   loops for multiple occurrences by passing an incremented pointer
2899    
2900    4. PCRE wasn't doing the "first character" optimization for patterns starting
2901    with \b or \B, though it was doing it for other lookbehind assertions. That is,
2902    it wasn't noticing that a match for a pattern such as /\bxyz/ has to start with
2903    the letter 'x'. On long subject strings, this gives a significant speed-up.
2904    
2905    
2906    Version 2.05 21-Apr-99
2907    ----------------------
2908    
2909    1. Changed the type of magic_number from int to long int so that it works
2910    properly on 16-bit systems.
2911    
2912    2. Fixed a bug which caused patterns starting with .* not to work correctly
2913    when the subject string contained newline characters. PCRE was assuming
2914    anchoring for such patterns in all cases, which is not correct because .* will
2915    not pass a newline unless PCRE_DOTALL is set. It now assumes anchoring only if
2916    DOTALL is set at top level; otherwise it knows that patterns starting with .*
2917    must be retried after every newline in the subject.
2918    
2919    
2920    Version 2.04 18-Feb-99
2921    ----------------------
2922    
2923    1. For parenthesized subpatterns with repeats whose minimum was zero, the
2924    computation of the store needed to hold the pattern was incorrect (too large).
2925    If such patterns were nested a few deep, this could multiply and become a real
2926    problem.
2927    
2928    2. Added /M option to pcretest to show the memory requirement of a specific
2929    pattern. Made -m a synonym of -s (which does this globally) for compatibility.
2930    
2931    3. Subpatterns of the form (regex){n,m} (i.e. limited maximum) were being
2932    compiled in such a way that the backtracking after subsequent failure was
2933    pessimal. Something like (a){0,3} was compiled as (a)?(a)?(a)? instead of
2934    ((a)((a)(a)?)?)? with disastrous performance if the maximum was of any size.
2935    
2936    
2937    Version 2.03 02-Feb-99
2938    ----------------------
2939    
2940    1. Fixed typo and small mistake in man page.
2941    
2942    2. Added 4th condition (GPL supersedes if conflict) and created separate
2943    LICENCE file containing the conditions.
2944    
2945    3. Updated pcretest so that patterns such as /abc\/def/ work like they do in
2946    Perl, that is the internal \ allows the delimiter to be included in the
2947    pattern. Locked out the use of \ as a delimiter. If \ immediately follows
2948    the final delimiter, add \ to the end of the pattern (to test the error).
2949    
2950    4. Added the convenience functions for extracting substrings after a successful
2951    match. Updated pcretest to make it able to test these functions.
2952    
2953    
2954    Version 2.02 14-Jan-99
2955    ----------------------
2956    
2957    1. Initialized the working variables associated with each extraction so that
2958    their saving and restoring doesn't refer to uninitialized store.
2959    
2960    2. Put dummy code into study.c in order to trick the optimizer of the IBM C
2961    compiler for OS/2 into generating correct code. Apparently IBM isn't going to
2962    fix the problem.
2963    
2964    3. Pcretest: the timing code wasn't using LOOPREPEAT for timing execution
2965    calls, and wasn't printing the correct value for compiling calls. Increased the
2966    default value of LOOPREPEAT, and the number of significant figures in the
2967    times.
2968    
2969    4. Changed "/bin/rm" in the Makefile to "-rm" so it works on Windows NT.
2970    
2971    5. Renamed "deftables" as "dftables" to get it down to 8 characters, to avoid
2972    a building problem on Windows NT with a FAT file system.
2973    
2974    
2975    Version 2.01 21-Oct-98
2976    ----------------------
2977    
2978    1. Changed the API for pcre_compile() to allow for the provision of a pointer
2979    to character tables built by pcre_maketables() in the current locale. If NULL
2980    is passed, the default tables are used.
2981    
2982    
2983    Version 2.00 24-Sep-98
2984    ----------------------
2985    
2986    1. Since the (>?) facility is in Perl 5.005, don't require PCRE_EXTRA to enable
2987    it any more.
2988    
2989    2. Allow quantification of (?>) groups, and make it work correctly.
2990    
2991    3. The first character computation wasn't working for (?>) groups.
2992    
2993    4. Correct the implementation of \Z (it is permitted to match on the \n at the
2994    end of the subject) and add 5.005's \z, which really does match only at the
2995    very end of the subject.
2996    
2997    5. Remove the \X "cut" facility; Perl doesn't have it, and (?> is neater.
2998    
2999    6. Remove the ability to specify CASELESS, MULTILINE, DOTALL, and
3000    DOLLAR_END_ONLY at runtime, to make it possible to implement the Perl 5.005
3001    localized options. All options to pcre_study() were also removed.
3002    
3003    7. Add other new features from 5.005:
3004    
3005       $(?<=           positive lookbehind
3006       $(?<!           negative lookbehind
3007       (?imsx-imsx)    added the unsetting capability
3008                       such a setting is global if at outer level; local otherwise
3009       (?imsx-imsx:)   non-capturing groups with option setting
3010       (?(cond)re|re)  conditional pattern matching
3011    
3012       A backreference to itself in a repeated group matches the previous
3013       captured string.
3014    
3015    8. General tidying up of studying (both automatic and via "study")
3016    consequential on the addition of new assertions.
3017    
3018    9. As in 5.005, unlimited repeated groups that could match an empty substring
3019    are no longer faulted at compile time. Instead, the loop is forcibly broken at
3020    runtime if any iteration does actually match an empty substring.
3021    
3022    10. Include the RunTest script in the distribution.
3023    
3024    11. Added tests from the Perl 5.005_02 distribution. This showed up a few
3025    discrepancies, some of which were old and were also with respect to 5.004. They
3026    have now been fixed.
3027    
3028    
3029    Version 1.09 28-Apr-98
3030    ----------------------
3031    
3032    1. A negated single character class followed by a quantifier with a minimum
3033    value of one (e.g.  [^x]{1,6}  ) was not compiled correctly. This could lead to
3034    program crashes, or just wrong answers. This did not apply to negated classes
3035    containing more than one character, or to minima other than one.
3036    
3037    
3038    Version 1.08 27-Mar-98
3039    ----------------------
3040    
3041    1. Add PCRE_UNGREEDY to invert the greediness of quantifiers.
3042    
3043    2. Add (?U) and (?X) to set PCRE_UNGREEDY and PCRE_EXTRA respectively. The
3044    latter must appear before anything that relies on it in the pattern.
3045    
3046    
3047    Version 1.07 16-Feb-98
3048    ----------------------
3049    
3050    1. A pattern such as /((a)*)*/ was not being diagnosed as in error (unlimited
3051    repeat of a potentially empty string).
3052    
3053    
3054  Version 1.06 23-Jan-98  Version 1.06 23-Jan-98
3055  ----------------------  ----------------------

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