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revision 63 by nigel, Sat Feb 24 21:40:03 2007 UTC revision 336 by ph10, Sat Apr 12 15:59:03 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 4.00 17-Feb-03  Version 7.7 05-Mar-08
5  ----------------------  ---------------------
6    
7    1.  Applied Craig's patch to sort out a long long problem: "If we can't convert
8        a string to a long long, pretend we don't even have a long long." This is
9        done by checking for the strtoq, strtoll, and _strtoi64 functions.
10    
11    2.  Applied Craig's patch to pcrecpp.cc to restore ABI compatibility with
12        pre-7.6 versions, which defined a global no_arg variable instead of putting
13        it in the RE class. (See also #8 below.)
14    
15    3.  Remove a line of dead code, identified by coverity and reported by Nuno
16        Lopes.
17    
18    4.  Fixed two related pcregrep bugs involving -r with --include or --exclude:
19    
20        (1) The include/exclude patterns were being applied to the whole pathnames
21            of files, instead of just to the final components.
22    
23        (2) If there was more than one level of directory, the subdirectories were
24            skipped unless they satisfied the include/exclude conditions. This is
25            inconsistent with GNU grep (and could even be seen as contrary to the
26            pcregrep specification - which I improved to make it absolutely clear).
27            The action now is always to scan all levels of directory, and just
28            apply the include/exclude patterns to regular files.
29    
30    5.  Added the --include_dir and --exclude_dir patterns to pcregrep, and used
31        --exclude_dir in the tests to avoid scanning .svn directories.
32    
33    6.  Applied Craig's patch to the QuoteMeta function so that it escapes the
34        NUL character as backslash + 0 rather than backslash + NUL, because PCRE
35        doesn't support NULs in patterns.
36    
37    7.  Added some missing "const"s to declarations of static tables in
38        pcre_compile.c and pcre_dfa_exec.c.
39    
40    8.  Applied Craig's patch to pcrecpp.cc to fix a problem in OS X that was
41        caused by fix #2  above. (Subsequently also a second patch to fix the
42        first patch. And a third patch - this was a messy problem.)
43    
44    9.  Applied Craig's patch to remove the use of push_back().
45    
46    10. Applied Alan Lehotsky's patch to add REG_STARTEND support to the POSIX
47        matching function regexec().
48    
49    11. Added support for the Oniguruma syntax \g<name>, \g<n>, \g'name', \g'n',
50        which, however, unlike Perl's \g{...}, are subroutine calls, not back
51        references. PCRE supports relative numbers with this syntax (I don't think
52        Oniguruma does).
53    
54    12. Previously, a group with a zero repeat such as (...){0} was completely
55        omitted from the compiled regex. However, this means that if the group
56        was called as a subroutine from elsewhere in the pattern, things went wrong
57        (an internal error was given). Such groups are now left in the compiled
58        pattern, with a new opcode that causes them to be skipped at execution
59        time.
60    
61    13. Added the PCRE_JAVASCRIPT_COMPAT option. This currently does two things:
62        (a) A lone ] character is dis-allowed (Perl treats it as data).
63        (b) A back reference to an unmatched subpattern matches an empty string
64            (Perl fails the current match path).
65    
66    
67    Version 7.6 28-Jan-08
68    ---------------------
69    
70    1.  A character class containing a very large number of characters with
71        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
72        overflow.
73    
74    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
75        HAVE_LONG_LONG is not defined.
76    
77    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
78        bring them up to date and include new features. This patch includes:
79    
80        - Fixed PH's badly added libz and libbz2 support.
81        - Fixed a problem with static linking.
82        - Added pcredemo. [But later removed - see 7 below.]
83        - Fixed dftables problem and added an option.
84        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
85            HAVE_LONG_LONG.
86        - Added readline support for pcretest.
87        - Added an listing of the option settings after cmake has run.
88    
89    4.  A user submitted a patch to Makefile that makes it easy to create
90        "pcre.dll" under mingw when using Configure/Make. I added stuff to
91        Makefile.am that cause it to include this special target, without
92        affecting anything else. Note that the same mingw target plus all
93        the other distribution libraries and programs are now supported
94        when configuring with CMake (see 6 below) instead of with
95        Configure/Make.
96    
97    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
98        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
99        exported in the Windows port". It has not yet been confirmed that the patch
100        solves the problem, but it does no harm.
101    
102    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
103        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
104        with CMake, and also correct the comment about stack recursion.
105    
106    7.  Remove the automatic building of pcredemo from the ./configure system and
107        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
108        of a program that users should build themselves after PCRE is installed, so
109        building it automatically is not really right. What is more, it gave
110        trouble in some build environments.
111    
112    8.  Further tidies to CMakeLists.txt from Sheri and Christian.
113    
114    
115    Version 7.5 10-Jan-08
116    ---------------------
117    
118    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
119        values in parens when parsing an RE using the C++ wrapper."
120    
121    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
122        Characters greater than 255 were excluded from the class instead of being
123        included.
124    
125    3.  The same bug as (2) above applied to negated POSIX classes such as
126        [:^space:].
127    
128    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
129        defined or documented. It seems to have been a typo for PCRE_STATIC, so
130        I have changed it.
131    
132    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
133        first named subpattern) and a construct such as (?&a) would reference the
134        first named subpattern whose name started with "a" (in other words, the
135        length check was missing). Both these problems are fixed. "Subpattern name
136        expected" is now given for (?&) (a zero-length name), and this patch also
137        makes it give the same error for \k'' (previously it complained that that
138        was a reference to a non-existent subpattern).
139    
140    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
141        this is right because (?- can be followed by option settings as well as by
142        digits. I have, however, made the messages clearer.
143    
144    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
145        than the number used in the conditional) now cause a compile-time error.
146        This is actually not compatible with Perl, which accepts such patterns, but
147        treats the conditional as always being FALSE (as PCRE used to), but it
148        seems to me that giving a diagnostic is better.
149    
150    8.  Change "alphameric" to the more common word "alphanumeric" in comments
151        and messages.
152    
153    9.  Fix two occurrences of "backslash" in comments that should have been
154        "backspace".
155    
156    10. Remove two redundant lines of code that can never be obeyed (their function
157        was moved elsewhere).
158    
159    11. The program that makes PCRE's Unicode character property table had a bug
160        which caused it to generate incorrect table entries for sequences of
161        characters that have the same character type, but are in different scripts.
162        It amalgamated them into a single range, with the script of the first of
163        them. In other words, some characters were in the wrong script. There were
164        thirteen such cases, affecting characters in the following ranges:
165    
166          U+002b0 - U+002c1
167          U+0060c - U+0060d
168          U+0061e - U+00612
169          U+0064b - U+0065e
170          U+0074d - U+0076d
171          U+01800 - U+01805
172          U+01d00 - U+01d77
173          U+01d9b - U+01dbf
174          U+0200b - U+0200f
175          U+030fc - U+030fe
176          U+03260 - U+0327f
177          U+0fb46 - U+0fbb1
178          U+10450 - U+1049d
179    
180    12. The -o option (show only the matching part of a line) for pcregrep was not
181        compatible with GNU grep in that, if there was more than one match in a
182        line, it showed only the first of them. It now behaves in the same way as
183        GNU grep.
184    
185    13. If the -o and -v options were combined for pcregrep, it printed a blank
186        line for every non-matching line. GNU grep prints nothing, and pcregrep now
187        does the same. The return code can be used to tell if there were any
188        non-matching lines.
189    
190    14. Added --file-offsets and --line-offsets to pcregrep.
191    
192    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
193        infinitely looping recursion. The bug was that positive lookaheads were not
194        being skipped when checking for a possible empty match (negative lookaheads
195        and both kinds of lookbehind were skipped).
196    
197    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
198        inclusion of <windows.h> to before rather than after the definition of
199        INVALID_FILE_ATTRIBUTES (patch from David Byron).
200    
201    17. Specifying a possessive quantifier with a specific limit for a Unicode
202        character property caused pcre_compile() to compile bad code, which led at
203        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
204        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
205        caused the error; without that there was no problem.
206    
207    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
208    
209    19. Added --enable-pcretest-libreadline.
210    
211    20. In pcrecpp.cc, the variable 'count' was incremented twice in
212        RE::GlobalReplace(). As a result, the number of replacements returned was
213        double what it should be. I removed one of the increments, but Craig sent a
214        later patch that removed the other one (the right fix) and added unit tests
215        that check the return values (which was not done before).
216    
217    21. Several CMake things:
218    
219        (1) Arranged that, when cmake is used on Unix, the libraries end up with
220            the names libpcre and libpcreposix, not just pcre and pcreposix.
221    
222        (2) The above change means that pcretest and pcregrep are now correctly
223            linked with the newly-built libraries, not previously installed ones.
224    
225        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
226    
227    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
228        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
229        UTF-8 newline character). The key issue is that the pattern starts .*;
230        this means that the match must be either at the beginning, or after a
231        newline. The bug was in the code for advancing after a failed match and
232        checking that the new position followed a newline. It was not taking
233        account of UTF-8 characters correctly.
234    
235    23. PCRE was behaving differently from Perl in the way it recognized POSIX
236        character classes. PCRE was not treating the sequence [:...:] as a
237        character class unless the ... were all letters. Perl, however, seems to
238        allow any characters between [: and :], though of course it rejects as
239        unknown any "names" that contain non-letters, because all the known class
240        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
241        for example, whereas PCRE did not - it did not recognize a POSIX character
242        class. This seemed a bit dangerous, so the code has been changed to be
243        closer to Perl. The behaviour is not identical to Perl, because PCRE will
244        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
245        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
246        Perl does, and where it didn't before.
247    
248    24. Rewrite so as to remove the single use of %n from pcregrep because in some
249        Windows environments %n is disabled by default.
250    
251    
252    Version 7.4 21-Sep-07
253    ---------------------
254    
255    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
256        means that a class such as [\s] counted as "explicit reference to CR or
257        LF". That isn't really right - the whole point of the change was to try to
258        help when there was an actual mention of one of the two characters. So now
259        the change happens only if \r or \n (or a literal CR or LF) character is
260        encountered.
261    
262    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
263        of both had grown to the point where there were only 3 bits left.
264        Fortunately, there was spare space in the data structure, and so I have
265        moved the internal flags into a new 16-bit field to free up more option
266        bits.
267    
268    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
269        but did not set the internal JCHANGED flag - either of these is enough to
270        control the way the "get" function works - but the PCRE_INFO_JCHANGED
271        facility is supposed to tell if (?J) was ever used, so now (?J) at the
272        start sets both bits.
273    
274    4.  Added options (at build time, compile time, exec time) to change \R from
275        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
276    
277    5.  doc/pcresyntax.html was missing from the distribution.
278    
279    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
280        compatibility, even though it is no longer used.
281    
282    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
283        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
284        windows.h file is present (where different names are used). [This was
285        reversed later after testing - see 16 below.]
286    
287    8.  Changed all #include <config.h> to #include "config.h". There were also
288        some further <pcre.h> cases that I changed to "pcre.h".
289    
290    9.  When pcregrep was used with the --colour option, it missed the line ending
291        sequence off the lines that it output.
292    
293    10. It was pointed out to me that arrays of string pointers cause lots of
294        relocations when a shared library is dynamically loaded. A technique of
295        using a single long string with a table of offsets can drastically reduce
296        these. I have refactored PCRE in four places to do this. The result is
297        dramatic:
298    
299          Originally:                          290
300          After changing UCP table:            187
301          After changing error message table:   43
302          After changing table of "verbs"       36
303          After changing table of Posix names   22
304    
305        Thanks to the folks working on Gregex for glib for this insight.
306    
307    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
308        unicode-properties was also set.
309    
310    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
311    
312    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
313        checked only for CRLF.
314    
315    14. Added casts to pcretest.c to avoid compiler warnings.
316    
317    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
318    
319    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
320        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
321        entirely. This removes changes made in 7 above.
322    
323    17. The CMake files have been updated, and there is now more information about
324        building with CMake in the NON-UNIX-USE document.
325    
326    
327    Version 7.3 28-Aug-07
328    ---------------------
329    
330     1. In the rejigging of the build system that eventually resulted in 7.1, the
331        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
332        brackets there is not right, since it causes compilers to look for an
333        installed pcre.h, not the version that is in the source that is being
334        compiled (which of course may be different). I have changed it back to:
335    
336          #include "pcre.h"
337    
338        I have a vague recollection that the change was concerned with compiling in
339        different directories, but in the new build system, that is taken care of
340        by the VPATH setting the Makefile.
341    
342     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
343        when the subject happened to end in the byte 0x85 (e.g. if the last
344        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
345        characters but of course it shouldn't be taken as a newline when it is part
346        of another character. The bug was that, for an unlimited repeat of . in
347        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
348        characters when looking for a newline.
349    
350     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
351    
352     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
353        in debug output.
354    
355     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
356        long printing in the pcrecpp unittest when running under MinGW.
357    
358     6. ESC_K was left out of the EBCDIC table.
359    
360     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
361        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
362        limit also applies to "virtual nesting" when a pattern is recursive, and in
363        this case 1000 isn't so big. I have been able to remove this limit at the
364        expense of backing off one optimization in certain circumstances. Normally,
365        when pcre_exec() would call its internal match() function recursively and
366        immediately return the result unconditionally, it uses a "tail recursion"
367        feature to save stack. However, when a subpattern that can match an empty
368        string has an unlimited repetition quantifier, it no longer makes this
369        optimization. That gives it a stack frame in which to save the data for
370        checking that an empty string has been matched. Previously this was taken
371        from the 1000-entry workspace that had been reserved. So now there is no
372        explicit limit, but more stack is used.
373    
374     8. Applied Daniel's patches to solve problems with the import/export magic
375        syntax that is required for Windows, and which was going wrong for the
376        pcreposix and pcrecpp parts of the library. These were overlooked when this
377        problem was solved for the main library.
378    
379     9. There were some crude static tests to avoid integer overflow when computing
380        the size of patterns that contain repeated groups with explicit upper
381        limits. As the maximum quantifier is 65535, the maximum group length was
382        set at 30,000 so that the product of these two numbers did not overflow a
383        32-bit integer. However, it turns out that people want to use groups that
384        are longer than 30,000 bytes (though not repeat them that many times).
385        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
386        made it possible to implement the integer overflow checks in a much more
387        dynamic way, which I have now done. The artificial limitation on group
388        length has been removed - we now have only the limit on the total length of
389        the compiled pattern, which depends on the LINK_SIZE setting.
390    
391    10. Fixed a bug in the documentation for get/copy named substring when
392        duplicate names are permitted. If none of the named substrings are set, the
393        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
394        empty string.
395    
396    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
397        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
398        because the ] is interpreted as the first data character and the
399        terminating ] is not found. PCRE has been made compatible with Perl in this
400        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
401        cause memory overwriting.
402    
403    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
404        string has been matched (to stop an infinite loop). It was not recognizing
405        a conditional subpattern that could match an empty string if that
406        subpattern was within another subpattern. For example, it looped when
407        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
408        condition was not nested. This bug has been fixed.
409    
410    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
411        past the start of the subject in the presence of bytes with the top bit
412        set, for example "\x8aBCD".
413    
414    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
415        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
416    
417    14. Optimized (?!) to (*FAIL).
418    
419    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
420        This restricts code points to be within the range 0 to 0x10FFFF, excluding
421        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
422        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
423        does: it's just the validity check that is more restrictive.
424    
425    16. Inserted checks for integer overflows during escape sequence (backslash)
426        processing, and also fixed erroneous offset values for syntax errors during
427        backslash processing.
428    
429    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
430        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
431    
432    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
433        caused an overrun.
434    
435    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
436        something other than just ASCII characters) inside a group that had an
437        unlimited repeat caused a loop at compile time (while checking to see
438        whether the group could match an empty string).
439    
440    20. Debugging a pattern containing \p or \P could cause a crash. For example,
441        [\P{Any}] did so. (Error in the code for printing property names.)
442    
443    21. An orphan \E inside a character class could cause a crash.
444    
445    22. A repeated capturing bracket such as (A)? could cause a wild memory
446        reference during compilation.
447    
448    23. There are several functions in pcre_compile() that scan along a compiled
449        expression for various reasons (e.g. to see if it's fixed length for look
450        behind). There were bugs in these functions when a repeated \p or \P was
451        present in the pattern. These operators have additional parameters compared
452        with \d, etc, and these were not being taken into account when moving along
453        the compiled data. Specifically:
454    
455        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
456            length.
457    
458        (b) An item such as \pL+ within a repeated group could cause crashes or
459            loops.
460    
461        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
462            "reference to non-existent subpattern" error.
463    
464        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
465    
466    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
467        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
468    
469    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
470    
471    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
472        character were causing crashes (broken optimization).
473    
474    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
475        \p or \P) caused a compile-time loop.
476    
477    28. More problems have arisen in unanchored patterns when CRLF is a valid line
478        break. For example, the unstudied pattern [\r\n]A does not match the string
479        "\r\nA" because change 7.0/46 below moves the current point on by two
480        characters after failing to match at the start. However, the pattern \nA
481        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
482        the same is true. There doesn't seem any very clean way out of this, but
483        what I have chosen to do makes the common cases work: PCRE now takes note
484        of whether there can be an explicit match for \r or \n anywhere in the
485        pattern, and if so, 7.0/46 no longer applies. As part of this change,
486        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
487        pattern has explicit CR or LF references.
488    
489    29. Added (*CR) etc for changing newline setting at start of pattern.
490    
491    
492    Version 7.2 19-Jun-07
493    ---------------------
494    
495     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
496        which is apparently normally available under Windows.
497    
498     2. Re-jig the pcregrep tests with different newline settings in an attempt
499        to make them independent of the local environment's newline setting.
500    
501     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
502    
503     4. Some of the "internals" tests were previously cut out when the link size
504        was not 2, because the output contained actual offsets. The recent new
505        "Z" feature of pcretest means that these can be cut out, making the tests
506        usable with all link sizes.
507    
508     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
509        stack recursion. This gives a massive performance boost under BSD, but just
510        a small improvement under Linux. However, it saves one field in the frame
511        in all cases.
512    
513     6. Added more features from the forthcoming Perl 5.10:
514    
515        (a) (?-n) (where n is a string of digits) is a relative subroutine or
516            recursion call. It refers to the nth most recently opened parentheses.
517    
518        (b) (?+n) is also a relative subroutine call; it refers to the nth next
519            to be opened parentheses.
520    
521        (c) Conditions that refer to capturing parentheses can be specified
522            relatively, for example, (?(-2)... or (?(+3)...
523    
524        (d) \K resets the start of the current match so that everything before
525            is not part of it.
526    
527        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
528    
529        (f) \g{name} is another synonym - part of Perl 5.10's unification of
530            reference syntax.
531    
532        (g) (?| introduces a group in which the numbering of parentheses in each
533            alternative starts with the same number.
534    
535        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
536    
537     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
538        PCRE_INFO_JCHANGED.
539    
540     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
541        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
542        for detecting groups that can match an empty string.
543    
544     9. A pattern with a very large number of alternatives (more than several
545        hundred) was running out of internal workspace during the pre-compile
546        phase, where pcre_compile() figures out how much memory will be needed. A
547        bit of new cunning has reduced the workspace needed for groups with
548        alternatives. The 1000-alternative test pattern now uses 12 bytes of
549        workspace instead of running out of the 4096 that are available.
550    
551    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
552    
553    11. Applied patch from Google to remove an optimization that didn't quite work.
554        The report of the bug said:
555    
556          pcrecpp::RE("a*").FullMatch("aaa") matches, while
557          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
558          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
559    
560    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
561        it matched the wrong number of bytes.
562    
563    
564    Version 7.1 24-Apr-07
565    ---------------------
566    
567     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
568        that is more "standard", making use of automake and other Autotools. There
569        is some re-arrangement of the files and adjustment of comments consequent
570        on this.
571    
572     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
573        for recursive directory scanning broke on some systems because the files
574        are not scanned in any specific order and on different systems the order
575        was different. A call to "sort" has been inserted into RunGrepTest for the
576        approprate test as a short-term fix. In the longer term there may be an
577        alternative.
578    
579     3. I had an email from Eric Raymond about problems translating some of PCRE's
580        man pages to HTML (despite the fact that I distribute HTML pages, some
581        people do their own conversions for various reasons). The problems
582        concerned the use of low-level troff macros .br and .in. I have therefore
583        removed all such uses from the man pages (some were redundant, some could
584        be replaced by .nf/.fi pairs). The 132html script that I use to generate
585        HTML has been updated to handle .nf/.fi and to complain if it encounters
586        .br or .in.
587    
588     4. Updated comments in configure.ac that get placed in config.h.in and also
589        arranged for config.h to be included in the distribution, with the name
590        config.h.generic, for the benefit of those who have to compile without
591        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
592    
593     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
594        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
595        makevp.bat for the current PCRE, using the additional files
596        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
597    
598     6. A Windows user reported a minor discrepancy with test 2, which turned out
599        to be caused by a trailing space on an input line that had got lost in his
600        copy. The trailing space was an accident, so I've just removed it.
601    
602     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
603        that is needed.
604    
605     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
606        as "const" (a) because they are and (b) because it helps the PHP
607        maintainers who have recently made a script to detect big data structures
608        in the php code that should be moved to the .rodata section. I remembered
609        to update Builducptable as well, so it won't revert if ucptable.h is ever
610        re-created.
611    
612     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
613        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
614        order to be able to cut out the UTF-8 tables in the latter when UTF-8
615        support is not required. This saves 1.5-2K of code, which is important in
616        some applications.
617    
618        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
619        so as not to refer to the tables, even though these functions will never be
620        called when UTF-8 support is disabled. Otherwise there are problems with a
621        shared library.
622    
623    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
624    
625        (a) It was defining its arguments as char * instead of void *.
626    
627        (b) It was assuming that all moves were upwards in memory; this was true
628            a long time ago when I wrote it, but is no longer the case.
629    
630        The emulated memove() is provided for those environments that have neither
631        memmove() nor bcopy(). I didn't think anyone used it these days, but that
632        is clearly not the case, as these two bugs were recently reported.
633    
634    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
635        and Detrail to create the HTML documentation, the .txt form of the man
636        pages, and it removes trailing spaces from listed files. It also creates
637        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
638        case, it wraps all the #defines with #ifndefs. This script should be run
639        before "make dist".
640    
641    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
642        with Unicode property support.
643    
644        (a) For a maximizing quantifier, if the two different cases of the
645            character were of different lengths in their UTF-8 codings (there are
646            some cases like this - I found 11), and the matching function had to
647            back up over a mixture of the two cases, it incorrectly assumed they
648            were both the same length.
649    
650        (b) When PCRE was configured to use the heap rather than the stack for
651            recursion during matching, it was not correctly preserving the data for
652            the other case of a UTF-8 character when checking ahead for a match
653            while processing a minimizing repeat. If the check also involved
654            matching a wide character, but failed, corruption could cause an
655            erroneous result when trying to check for a repeat of the original
656            character.
657    
658    13. Some tidying changes to the testing mechanism:
659    
660        (a) The RunTest script now detects the internal link size and whether there
661            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
662            values substituted by "configure". (The RunGrepTest script already did
663            this for UTF-8.) The configure.ac script no longer substitutes the
664            relevant variables.
665    
666        (b) The debugging options /B and /D in pcretest show the compiled bytecode
667            with length and offset values. This means that the output is different
668            for different internal link sizes. Test 2 is skipped for link sizes
669            other than 2 because of this, bypassing the problem. Unfortunately,
670            there was also a test in test 3 (the locale tests) that used /B and
671            failed for link sizes other than 2. Rather than cut the whole test out,
672            I have added a new /Z option to pcretest that replaces the length and
673            offset values with spaces. This is now used to make test 3 independent
674            of link size. (Test 2 will be tidied up later.)
675    
676    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
677        segmentation fault instead of returning the appropriate error message.
678    
679    15. In multiline mode when the newline sequence was set to "any", the pattern
680        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
681        This doesn't seem right; it now treats the CRLF combination as the line
682        ending, and so does not match in that case. It's only a pattern such as ^$
683        that would hit this one: something like ^ABC$ would have failed after \r
684        and then tried again after \r\n.
685    
686    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
687        in an attempt to make files that differ only in their line terminators
688        compare equal. This works on Linux.
689    
690    17. Under certain error circumstances pcregrep might try to free random memory
691        as it exited. This is now fixed, thanks to valgrind.
692    
693    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
694        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
695        was because its rules for how to advance for /g after matching an empty
696        string at the end of a line did not allow for this case. They now check for
697        it specially.
698    
699    20. pcretest is supposed to handle patterns and data of any length, by
700        extending its buffers when necessary. It was getting this wrong when the
701        buffer for a data line had to be extended.
702    
703    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
704        CRLF as a newline sequence.
705    
706    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
707        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
708        I have nevertheless tidied it up.
709    
710    23. Added some casts to kill warnings from HP-UX ia64 compiler.
711    
712    24. Added a man page for pcre-config.
713    
714    
715    Version 7.0 19-Dec-06
716    ---------------------
717    
718     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
719        moving to gcc 4.1.1.
720    
721     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
722        sys/time.h, which is documented as needed for this function. It doesn't
723        seem to matter on Linux, but it showed up on some releases of OS X.
724    
725     3. It seems that there are systems where bytes whose values are greater than
726        127 match isprint() in the "C" locale. The "C" locale should be the
727        default when a C program starts up. In most systems, only ASCII printing
728        characters match isprint(). This difference caused the output from pcretest
729        to vary, making some of the tests fail. I have changed pcretest so that:
730    
731        (a) When it is outputting text in the compiled version of a pattern, bytes
732            other than 32-126 are always shown as hex escapes.
733    
734        (b) When it is outputting text that is a matched part of a subject string,
735            it does the same, unless a different locale has been set for the match
736            (using the /L modifier). In this case, it uses isprint() to decide.
737    
738     4. Fixed a major bug that caused incorrect computation of the amount of memory
739        required for a compiled pattern when options that changed within the
740        pattern affected the logic of the preliminary scan that determines the
741        length. The relevant options are -x, and -i in UTF-8 mode. The result was
742        that the computed length was too small. The symptoms of this bug were
743        either the PCRE error "internal error: code overflow" from pcre_compile(),
744        or a glibc crash with a message such as "pcretest: free(): invalid next
745        size (fast)". Examples of patterns that provoked this bug (shown in
746        pcretest format) are:
747    
748          /(?-x: )/x
749          /(?x)(?-x: \s*#\s*)/
750          /((?i)[\x{c0}])/8
751          /(?i:[\x{c0}])/8
752    
753        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
754        is now done differently.
755    
756     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
757        wrapper classes; (b) implement a new function in the C++ scanner that is
758        more efficient than the old way of doing things because it avoids levels of
759        recursion in the regex matching; (c) add a paragraph to the documentation
760        for the FullMatch() function.
761    
762     6. The escape sequence \n was being treated as whatever was defined as
763        "newline". Not only was this contrary to the documentation, which states
764        that \n is character 10 (hex 0A), but it also went horribly wrong when
765        "newline" was defined as CRLF. This has been fixed.
766    
767     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
768        was being set to -1 for the "end of line" case (supposedly a value that no
769        character can have). Though this value is never used (the check for end of
770        line is "zero bytes in current character"), it caused compiler complaints.
771        I've changed it to 0xffffffff.
772    
773     8. In pcre_version.c, the version string was being built by a sequence of
774        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
775        string (as it is for production releases) called a macro with an empty
776        argument. The C standard says the result of this is undefined. The gcc
777        compiler treats it as an empty string (which was what was wanted) but it is
778        reported that Visual C gives an error. The source has been hacked around to
779        avoid this problem.
780    
781     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
782        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
783        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
784        of them did).
785    
786    10. Originally, pcretest opened its input and output without "b"; then I was
787        told that "b" was needed in some environments, so it was added for release
788        5.0 to both the input and output. (It makes no difference on Unix-like
789        systems.) Later I was told that it is wrong for the input on Windows. I've
790        now abstracted the modes into two macros, to make it easier to fiddle with
791        them, and removed "b" from the input mode under Windows.
792    
793    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
794    
795    12. Added -help and --help to pcretest as an official way of being reminded
796        of the options.
797    
798    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
799        and pcrecpp.cc because they annoy compilers at high warning levels.
800    
801    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
802    
803    15. Fixed an occurrence of == in configure.ac that should have been = (shell
804        scripts are not C programs :-) and which was not noticed because it works
805        on Linux.
806    
807    16. pcretest is supposed to handle any length of pattern and data line (as one
808        line or as a continued sequence of lines) by extending its input buffer if
809        necessary. This feature was broken for very long pattern lines, leading to
810        a string of junk being passed to pcre_compile() if the pattern was longer
811        than about 50K.
812    
813    17. I have done a major re-factoring of the way pcre_compile() computes the
814        amount of memory needed for a compiled pattern. Previously, there was code
815        that made a preliminary scan of the pattern in order to do this. That was
816        OK when PCRE was new, but as the facilities have expanded, it has become
817        harder and harder to keep it in step with the real compile phase, and there
818        have been a number of bugs (see for example, 4 above). I have now found a
819        cunning way of running the real compile function in a "fake" mode that
820        enables it to compute how much memory it would need, while actually only
821        ever using a few hundred bytes of working memory and without too many
822        tests of the mode. This should make future maintenance and development
823        easier. A side effect of this work is that the limit of 200 on the nesting
824        depth of parentheses has been removed (though this was never a serious
825        limitation, I suspect). However, there is a downside: pcre_compile() now
826        runs more slowly than before (30% or more, depending on the pattern). I
827        hope this isn't a big issue. There is no effect on runtime performance.
828    
829    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
830        newline (only possible for the last line of a file) and it was a
831        pattern that set a locale (followed by /Lsomething), pcretest crashed.
832    
833    19. Added additional timing features to pcretest. (1) The -tm option now times
834        matching only, not compiling. (2) Both -t and -tm can be followed, as a
835        separate command line item, by a number that specifies the number of
836        repeats to use when timing. The default is 50000; this gives better
837        precision, but takes uncomfortably long for very large patterns.
838    
839    20. Extended pcre_study() to be more clever in cases where a branch of a
840        subpattern has no definite first character. For example, (a*|b*)[cd] would
841        previously give no result from pcre_study(). Now it recognizes that the
842        first character must be a, b, c, or d.
843    
844    21. There was an incorrect error "recursive call could loop indefinitely" if
845        a subpattern (or the entire pattern) that was being tested for matching an
846        empty string contained only one non-empty item after a nested subpattern.
847        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
848        incorrectly, because the \d was being skipped in the check.
849    
850    22. The pcretest program now has a new pattern option /B and a command line
851        option -b, which is equivalent to adding /B to every pattern. This causes
852        it to show the compiled bytecode, without the additional information that
853        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
854        is the same as /B/I).
855    
856    23. A new optimization is now able automatically to treat some sequences such
857        as a*b as a*+b. More specifically, if something simple (such as a character
858        or a simple class like \d) has an unlimited quantifier, and is followed by
859        something that cannot possibly match the quantified thing, the quantifier
860        is automatically "possessified".
861    
862    24. A recursive reference to a subpattern whose number was greater than 39
863        went wrong under certain circumstances in UTF-8 mode. This bug could also
864        have affected the operation of pcre_study().
865    
866    25. Realized that a little bit of performance could be had by replacing
867        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
868    
869    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
870    
871    27. Possessive quantifiers such as a++ were previously implemented by turning
872        them into atomic groups such as ($>a+). Now they have their own opcodes,
873        which improves performance. This includes the automatically created ones
874        from 23 above.
875    
876    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
877        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
878        the first matched character to be a colon. This applied both to named and
879        numbered groups.
880    
881    29. The ucpinternal.h header file was missing its idempotency #ifdef.
882    
883    30. I was sent a "project" file called libpcre.a.dev which I understand makes
884        building PCRE on Windows easier, so I have included it in the distribution.
885    
886    31. There is now a check in pcretest against a ridiculously large number being
887        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
888        loop, the loop is abandoned.
889    
890    32. Forward references to subpatterns in conditions such as (?(2)...) where
891        subpattern 2 is defined later cause pcre_compile() to search forwards in
892        the pattern for the relevant set of parentheses. This search went wrong
893        when there were unescaped parentheses in a character class, parentheses
894        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
895    
896    33. "Subroutine" calls and backreferences were previously restricted to
897        referencing subpatterns earlier in the regex. This restriction has now
898        been removed.
899    
900    34. Added a number of extra features that are going to be in Perl 5.10. On the
901        whole, these are just syntactic alternatives for features that PCRE had
902        previously implemented using the Python syntax or my own invention. The
903        other formats are all retained for compatibility.
904    
905        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
906            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
907            also .NET compatible.
908    
909        (b) A recursion or subroutine call to a named group can now be defined as
910            (?&name) as well as (?P>name).
911    
912        (c) A backreference to a named group can now be defined as \k<name> or
913            \k'name' as well as (?P=name). The new forms, as well as being in Perl
914            5.10, are also .NET compatible.
915    
916        (d) A conditional reference to a named group can now use the syntax
917            (?(<name>) or (?('name') as well as (?(name).
918    
919        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
920            groups (named and numbered) that are never evaluated inline, but can be
921            called as "subroutines" from elsewhere. In effect, the DEFINE condition
922            is always false. There may be only one alternative in such a group.
923    
924        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
925            as the simple (?(R). The condition is true only if the most recent
926            recursion is that of the given number or name. It does not search out
927            through the entire recursion stack.
928    
929        (g) The escape \gN or \g{N} has been added, where N is a positive or
930            negative number, specifying an absolute or relative reference.
931    
932    35. Tidied to get rid of some further signed/unsigned compiler warnings and
933        some "unreachable code" warnings.
934    
935    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
936        things, this adds five new scripts.
937    
938    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
939        There were also incompatibilities regarding the handling of \Q..\E inside
940        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
941        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
942    
943    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
944        matches an empty string, and forcibly breaks the loop. There were bugs in
945        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
946        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
947        separate and independent bugs (that affected different cases) have been
948        fixed.
949    
950    39. Refactored the code to abolish the use of different opcodes for small
951        capturing bracket numbers. This is a tidy that I avoided doing when I
952        removed the limit on the number of capturing brackets for 3.5 back in 2001.
953        The new approach is not only tidier, it makes it possible to reduce the
954        memory needed to fix the previous bug (38).
955    
956    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
957        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
958        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
959        mode.
960    
961    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
962        report.
963    
964    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
965        copy construction and assignment in the C++ wrapper.
966    
967    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
968        couple of bugs that could have given wrong results in the "--newline=crlf"
969        case.
970    
971    44. Added a number of casts and did some reorganization of signed/unsigned int
972        variables following suggestions from Dair Grant. Also renamed the variable
973        "this" as "item" because it is a C++ keyword.
974    
975    45. Arranged for dftables to add
976    
977          #include "pcre_internal.h"
978    
979        to pcre_chartables.c because without it, gcc 4.x may remove the array
980        definition from the final binary if PCRE is built into a static library and
981        dead code stripping is activated.
982    
983    46. For an unanchored pattern, if a match attempt fails at the start of a
984        newline sequence, and the newline setting is CRLF or ANY, and the next two
985        characters are CRLF, advance by two characters instead of one.
986    
987    
988    Version 6.7 04-Jul-06
989    ---------------------
990    
991     1. In order to handle tests when input lines are enormously long, pcretest has
992        been re-factored so that it automatically extends its buffers when
993        necessary. The code is crude, but this _is_ just a test program. The
994        default size has been increased from 32K to 50K.
995    
996     2. The code in pcre_study() was using the value of the re argument before
997        testing it for NULL. (Of course, in any sensible call of the function, it
998        won't be NULL.)
999    
1000     3. The memmove() emulation function in pcre_internal.h, which is used on
1001        systems that lack both memmove() and bcopy() - that is, hardly ever -
1002        was missing a "static" storage class specifier.
1003    
1004     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
1005        containing an extended class (one that cannot be represented by a bitmap
1006        because it contains high-valued characters or Unicode property items, e.g.
1007        [\pZ]). Almost always one would set UTF-8 mode when processing such a
1008        pattern, but PCRE should not loop if you do not (it no longer does).
1009        [Detail: two cases were found: (a) a repeated subpattern containing an
1010        extended class; (b) a recursive reference to a subpattern that followed a
1011        previous extended class. It wasn't skipping over the extended class
1012        correctly when UTF-8 mode was not set.]
1013    
1014     5. A negated single-character class was not being recognized as fixed-length
1015        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
1016        compile error "lookbehind assertion is not fixed length".
1017    
1018     6. The RunPerlTest auxiliary script was showing an unexpected difference
1019        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
1020        write a Perl script that can interpret lines of an input file either as
1021        byte characters or as UTF-8, which is what "perltest" was being required to
1022        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
1023        can't do is switch easily at run time between having the "use utf8;" pragma
1024        or not. In the end, I fudged it by using the RunPerlTest script to insert
1025        "use utf8;" explicitly for the UTF-8 tests.
1026    
1027     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
1028        the end of the subject string, contrary to the documentation and to what
1029        Perl does. This was true of both matching functions. Now it matches only at
1030        the start of the subject and immediately after *internal* newlines.
1031    
1032     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
1033        a pointer to an int instead of a pointer to an unsigned long int. This
1034        caused problems on 64-bit systems.
1035    
1036     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
1037        instance of the 'standard' template library not being so standard".
1038    
1039    10. There was no check on the number of named subpatterns nor the maximum
1040        length of a subpattern name. The product of these values is used to compute
1041        the size of the memory block for a compiled pattern. By supplying a very
1042        long subpattern name and a large number of named subpatterns, the size
1043        computation could be caused to overflow. This is now prevented by limiting
1044        the length of names to 32 characters, and the number of named subpatterns
1045        to 10,000.
1046    
1047    11. Subpatterns that are repeated with specific counts have to be replicated in
1048        the compiled pattern. The size of memory for this was computed from the
1049        length of the subpattern and the repeat count. The latter is limited to
1050        65535, but there was no limit on the former, meaning that integer overflow
1051        could in principle occur. The compiled length of a repeated subpattern is
1052        now limited to 30,000 bytes in order to prevent this.
1053    
1054    12. Added the optional facility to have named substrings with the same name.
1055    
1056    13. Added the ability to use a named substring as a condition, using the
1057        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
1058        are numbers (not recommended). Forward references are permitted.
1059    
1060    14. Added forward references in named backreferences (if you see what I mean).
1061    
1062    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
1063        pattern could run off the end of the subject. For example, the pattern
1064        "(?s)(.{1,5})"8 did this with the subject "ab".
1065    
1066    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
1067        PCRE_CASELESS was set when matching characters that were quantified with ?
1068        or *.
1069    
1070    17. A character class other than a single negated character that had a minimum
1071        but no maximum quantifier - for example [ab]{6,} - was not handled
1072        correctly by pce_dfa_exec(). It would match only one character.
1073    
1074    18. A valid (though odd) pattern that looked like a POSIX character
1075        class but used an invalid character after [ (for example [[,abc,]]) caused
1076        pcre_compile() to give the error "Failed: internal error: code overflow" or
1077        in some cases to crash with a glibc free() error. This could even happen if
1078        the pattern terminated after [[ but there just happened to be a sequence of
1079        letters, a binary zero, and a closing ] in the memory that followed.
1080    
1081    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
1082        over the years. Originally (before any Unicode support), just the bottom 8
1083        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
1084        output from "man perlunicode" includes this:
1085    
1086          The regular expression compiler produces polymorphic opcodes.  That
1087          is, the pattern adapts to the data and automatically switches to
1088          the Unicode character scheme when presented with Unicode data--or
1089          instead uses a traditional byte scheme when presented with byte
1090          data.
1091    
1092        Sadly, a wide octal escape does not cause a switch, and in a string with
1093        no other multibyte characters, these octal escapes are treated as before.
1094        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
1095        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
1096        Unicode string.
1097    
1098        I have not perpetrated such confusion in PCRE. Up till now, it took just
1099        the bottom 8 bits, as in old Perl. I have now made octal escapes with
1100        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
1101        translate to the appropriate multibyte character.
1102    
1103    29. Applied some refactoring to reduce the number of warnings from Microsoft
1104        and Borland compilers. This has included removing the fudge introduced
1105        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
1106        a warning about an unused variable.
1107    
1108    21. PCRE has not included VT (character 0x0b) in the set of whitespace
1109        characters since release 4.0, because Perl (from release 5.004) does not.
1110        [Or at least, is documented not to: some releases seem to be in conflict
1111        with the documentation.] However, when a pattern was studied with
1112        pcre_study() and all its branches started with \s, PCRE still included VT
1113        as a possible starting character. Of course, this did no harm; it just
1114        caused an unnecessary match attempt.
1115    
1116    22. Removed a now-redundant internal flag bit that recorded the fact that case
1117        dependency changed within the pattern. This was once needed for "required
1118        byte" processing, but is no longer used. This recovers a now-scarce options
1119        bit. Also moved the least significant internal flag bit to the most-
1120        significant bit of the word, which was not previously used (hangover from
1121        the days when it was an int rather than a uint) to free up another bit for
1122        the future.
1123    
1124    23. Added support for CRLF line endings as well as CR and LF. As well as the
1125        default being selectable at build time, it can now be changed at runtime
1126        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
1127        specify that it is scanning data with non-default line endings.
1128    
1129    24. Changed the definition of CXXLINK to make it agree with the definition of
1130        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
1131    
1132    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
1133        recursions. This makes a big different to stack usage for some patterns.
1134    
1135    26. If a subpattern containing a named recursion or subroutine reference such
1136        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
1137        the space required for the compiled pattern went wrong and gave too small a
1138        value. Depending on the environment, this could lead to "Failed: internal
1139        error: code overflow at offset 49" or "glibc detected double free or
1140        corruption" errors.
1141    
1142    27. Applied patches from Google (a) to support the new newline modes and (b) to
1143        advance over multibyte UTF-8 characters in GlobalReplace.
1144    
1145    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
1146        difference for some implementation of PCRE in some Windows version.
1147    
1148    29. Added some extra testing facilities to pcretest:
1149    
1150        \q<number>   in a data line sets the "match limit" value
1151        \Q<number>   in a data line sets the "match recursion limt" value
1152        -S <number>  sets the stack size, where <number> is in megabytes
1153    
1154        The -S option isn't available for Windows.
1155    
1156    
1157    Version 6.6 06-Feb-06
1158    ---------------------
1159    
1160     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1161        in pcreposix.h. I have copied the definition from pcre.h.
1162    
1163     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1164        because pcre.h is no longer a built file.
1165    
1166     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1167        not normally included in the compiled code.
1168    
1169    
1170    Version 6.5 01-Feb-06
1171    ---------------------
1172    
1173     1. When using the partial match feature with pcre_dfa_exec(), it was not
1174        anchoring the second and subsequent partial matches at the new starting
1175        point. This could lead to incorrect results. For example, with the pattern
1176        /1234/, partially matching against "123" and then "a4" gave a match.
1177    
1178     2. Changes to pcregrep:
1179    
1180        (a) All non-match returns from pcre_exec() were being treated as failures
1181            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1182            error message is output. Some extra information is given for the
1183            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1184            probably the only errors that are likely to be caused by users (by
1185            specifying a regex that has nested indefinite repeats, for instance).
1186            If there are more than 20 of these errors, pcregrep is abandoned.
1187    
1188        (b) A binary zero was treated as data while matching, but terminated the
1189            output line if it was written out. This has been fixed: binary zeroes
1190            are now no different to any other data bytes.
1191    
1192        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1193            used to set a locale for matching. The --locale=xxxx long option has
1194            been added (no short equivalent) to specify a locale explicitly on the
1195            pcregrep command, overriding the environment variables.
1196    
1197        (d) When -B was used with -n, some line numbers in the output were one less
1198            than they should have been.
1199    
1200        (e) Added the -o (--only-matching) option.
1201    
1202        (f) If -A or -C was used with -c (count only), some lines of context were
1203            accidentally printed for the final match.
1204    
1205        (g) Added the -H (--with-filename) option.
1206    
1207        (h) The combination of options -rh failed to suppress file names for files
1208            that were found from directory arguments.
1209    
1210        (i) Added the -D (--devices) and -d (--directories) options.
1211    
1212        (j) Added the -F (--fixed-strings) option.
1213    
1214        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1215    
1216        (l) Added the --colo(u)r option.
1217    
1218        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1219            is not present by default.
1220    
1221     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1222        items such as (?R) or (?1), when the recursion could match a number of
1223        alternatives. If it matched one of the alternatives, but subsequently,
1224        outside the recursion, there was a failure, the code tried to back up into
1225        the recursion. However, because of the way PCRE is implemented, this is not
1226        possible, and the result was an incorrect result from the match.
1227    
1228        In order to prevent this happening, the specification of recursion has
1229        been changed so that all such subpatterns are automatically treated as
1230        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1231    
1232     4. I had overlooked the fact that, in some locales, there are characters for
1233        which isalpha() is true but neither isupper() nor islower() are true. In
1234        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1235        and ordfeminine) are like this. This affected the treatment of \w and \W
1236        when they appeared in character classes, but not when they appeared outside
1237        a character class. The bit map for "word" characters is now created
1238        separately from the results of isalnum() instead of just taking it from the
1239        upper, lower, and digit maps. (Plus the underscore character, of course.)
1240    
1241     5. The above bug also affected the handling of POSIX character classes such as
1242        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1243        permanent tables. Instead, the bit maps for such a class were previously
1244        created as the appropriate unions of the upper, lower, and digit bitmaps.
1245        Now they are created by subtraction from the [[:word:]] class, which has
1246        its own bitmap.
1247    
1248     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1249        It is created by subtracting the vertical space characters (\x09, \x0a,
1250        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1251        subtraction was done in the overall bitmap for a character class, meaning
1252        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1253        be recognized. This bug has been fixed.
1254    
1255     7. Patches from the folks at Google:
1256    
1257          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1258          real life, but is still worth protecting against".
1259    
1260          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1261          regular expressions".
1262    
1263          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1264          have it.
1265    
1266          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1267          "configure" and the latter not, in order to fix a problem somebody had
1268          with compiling the Arg class on HP-UX.
1269    
1270          (e) Improve the error-handling of the C++ wrapper a little bit.
1271    
1272          (f) New tests for checking recursion limiting.
1273    
1274     8. The pcre_memmove() function, which is used only if the environment does not
1275        have a standard memmove() function (and is therefore rarely compiled),
1276        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1277        returning a result (though PCRE never actually uses the result).
1278    
1279     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1280        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1281        returned instead of calling malloc() with an overflowing number that would
1282        most likely cause subsequent chaos.
1283    
1284    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1285    
1286    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1287        with this option is matched, the nmatch and pmatch options of regexec() are
1288        ignored.
1289    
1290    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1291        provided in case anyone wants to the the POSIX interface with UTF-8
1292        strings.
1293    
1294    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1295        C++ linking (needed for some HP-UX environments).
1296    
1297    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1298        (unused parameter) and in the pcre_printint() function (omitted "default"
1299        switch label when the default is to do nothing).
1300    
1301    15. Added some code to make it possible, when PCRE is compiled as a C++
1302        library, to replace subject pointers for pcre_exec() with a smart pointer
1303        class, thus making it possible to process discontinuous strings.
1304    
1305    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1306        much the same function. They were added by different people who were trying
1307        to make PCRE easy to compile on non-Unix systems. It has been suggested
1308        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1309        for compiling on Windows systems. I have therefore replaced it with
1310        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1311        defaults to "extern" for C or "extern C" for C++, which works fine on
1312        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1313        SCOPE with something explicit in config.h. In addition:
1314    
1315        (a) pcreposix.h still had just "extern" instead of either of these macros;
1316            I have replaced it with PCRE_DATA_SCOPE.
1317    
1318        (b) Functions such as _pcre_xclass(), which are internal to the library,
1319            but external in the C sense, all had PCRE_EXPORT in their definitions.
1320            This is apparently wrong for the Windows case, so I have removed it.
1321            (It makes no difference on Unix-like systems.)
1322    
1323    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1324        of recursive calls to match(). This is different to MATCH_LIMIT because
1325        that limits the total number of calls to match(), not all of which increase
1326        the depth of recursion. Limiting the recursion depth limits the amount of
1327        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1328        when PCRE is compiled, and changed at run time. A patch from Google adds
1329        this functionality to the C++ interface.
1330    
1331    18. Changes to the handling of Unicode character properties:
1332    
1333        (a) Updated the table to Unicode 4.1.0.
1334    
1335        (b) Recognize characters that are not in the table as "Cn" (undefined).
1336    
1337        (c) I revised the way the table is implemented to a much improved format
1338            which includes recognition of ranges. It now supports the ranges that
1339            are defined in UnicodeData.txt, and it also amalgamates other
1340            characters into ranges. This has reduced the number of entries in the
1341            table from around 16,000 to around 3,000, thus reducing its size
1342            considerably. I realized I did not need to use a tree structure after
1343            all - a binary chop search is just as efficient. Having reduced the
1344            number of entries, I extended their size from 6 bytes to 8 bytes to
1345            allow for more data.
1346    
1347        (d) Added support for Unicode script names via properties such as \p{Han}.
1348    
1349    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1350        matching that character.
1351    
1352    20. When matching a repeated Unicode property with a minimum greater than zero,
1353        (for example \pL{2,}), PCRE could look past the end of the subject if it
1354        reached it while seeking the minimum number of characters. This could
1355        happen only if some of the characters were more than one byte long, because
1356        there is a check for at least the minimum number of bytes.
1357    
1358    21. Refactored the implementation of \p and \P so as to be more general, to
1359        allow for more different types of property in future. This has changed the
1360        compiled form incompatibly. Anybody with saved compiled patterns that use
1361        \p or \P will have to recompile them.
1362    
1363    22. Added "Any" and "L&" to the supported property types.
1364    
1365    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1366        but give a compile time error if the value is greater than 0xff.
1367    
1368    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1369        accidentally not being installed or uninstalled.
1370    
1371    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1372        made were to insert the current release number. This seemed silly, because
1373        it made things harder for people building PCRE on systems that don't run
1374        "configure". I have turned pcre.h into a distributed file, no longer built
1375        by "configure", with the version identification directly included. There is
1376        no longer a pcre.h.in file.
1377    
1378        However, this change necessitated a change to the pcre-config script as
1379        well. It is built from pcre-config.in, and one of the substitutions was the
1380        release number. I have updated configure.ac so that ./configure now finds
1381        the release number by grepping pcre.h.
1382    
1383    26. Added the ability to run the tests under valgrind.
1384    
1385    
1386    Version 6.4 05-Sep-05
1387    ---------------------
1388    
1389     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1390        "--" to be printed when multiple files were scanned, even when none of the
1391        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1392        consider it to be a bug, and have restored the previous behaviour.
1393    
1394     2. A couple of code tidies to get rid of compiler warnings.
1395    
1396     3. The pcretest program used to cheat by referring to symbols in the library
1397        whose names begin with _pcre_. These are internal symbols that are not
1398        really supposed to be visible externally, and in some environments it is
1399        possible to suppress them. The cheating is now confined to including
1400        certain files from the library's source, which is a bit cleaner.
1401    
1402     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1403        file's purpose clearer.
1404    
1405     5. Reorganized pcre_ucp_findchar().
1406    
1407    
1408    Version 6.3 15-Aug-05
1409    ---------------------
1410    
1411     1. The file libpcre.pc.in did not have general read permission in the tarball.
1412    
1413     2. There were some problems when building without C++ support:
1414    
1415        (a) If C++ support was not built, "make install" and "make test" still
1416            tried to test it.
1417    
1418        (b) There were problems when the value of CXX was explicitly set. Some
1419            changes have been made to try to fix these, and ...
1420    
1421        (c) --disable-cpp can now be used to explicitly disable C++ support.
1422    
1423        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1424            backslash in a target when C++ was disabled. This confuses some
1425            versions of "make", apparently. Using an intermediate variable solves
1426            this. (Same for CPP_LOBJ.)
1427    
1428     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1429        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1430        necessary on certain architectures.
1431    
1432     4. Added a setting of -export-symbols-regex to the link command to remove
1433        those symbols that are exported in the C sense, but actually are local
1434        within the library, and not documented. Their names all begin with
1435        "_pcre_". This is not a perfect job, because (a) we have to except some
1436        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1437        available (and never for static libraries). I have made a note to try to
1438        find a way round (a) in the future.
1439    
1440    
1441    Version 6.2 01-Aug-05
1442    ---------------------
1443    
1444     1. There was no test for integer overflow of quantifier values. A construction
1445        such as {1111111111111111} would give undefined results. What is worse, if
1446        a minimum quantifier for a parenthesized subpattern overflowed and became
1447        negative, the calculation of the memory size went wrong. This could have
1448        led to memory overwriting.
1449    
1450     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1451    
1452     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1453        operating environments where this matters.
1454    
1455     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1456        PCRE options from within the C++ wrapper.
1457    
1458     5. Named capturing subpatterns were not being correctly counted when a pattern
1459        was compiled. This caused two problems: (a) If there were more than 100
1460        such subpatterns, the calculation of the memory needed for the whole
1461        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1462        back references of the form \12, where the number was greater than 9, were
1463        not recognized as back references, even though there were sufficient
1464        previous subpatterns.
1465    
1466     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1467        versions of gcc, e.g. 2.95.4.
1468    
1469    
1470    Version 6.1 21-Jun-05
1471    ---------------------
1472    
1473     1. There was one reference to the variable "posix" in pcretest.c that was not
1474        surrounded by "#if !defined NOPOSIX".
1475    
1476     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1477        the cross-check on the old pcre_info() function, for the benefit of the
1478        cut-down version of PCRE that is currently imported into Exim.
1479    
1480     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1481        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1482        patterns that start (?i) but I don't think that matters. The use of (?i) is
1483        just an example; this all applies to the other options as well.
1484    
1485     4. Since libtool seems to echo the compile commands it is issuing, the output
1486        from "make" can be reduced a bit by putting "@" in front of each libtool
1487        compile command.
1488    
1489     5. Patch from the folks at Google for configure.in to be a bit more thorough
1490        in checking for a suitable C++ installation before trying to compile the
1491        C++ stuff. This should fix a reported problem when a compiler was present,
1492        but no suitable headers.
1493    
1494     6. The man pages all had just "PCRE" as their title. I have changed them to
1495        be the relevant file name. I have also arranged that these names are
1496        retained in the file doc/pcre.txt, which is a concatenation in text format
1497        of all the man pages except the little individual ones for each function.
1498    
1499     7. The NON-UNIX-USE file had not been updated for the different set of source
1500        files that come with release 6. I also added a few comments about the C++
1501        wrapper.
1502    
1503    
1504    Version 6.0 07-Jun-05
1505    ---------------------
1506    
1507     1. Some minor internal re-organization to help with my DFA experiments.
1508    
1509     2. Some missing #ifdef SUPPORT_UCP conditionals in pcretest and printint that
1510        didn't matter for the library itself when fully configured, but did matter
1511        when compiling without UCP support, or within Exim, where the ucp files are
1512        not imported.
1513    
1514     3. Refactoring of the library code to split up the various functions into
1515        different source modules. The addition of the new DFA matching code (see
1516        below) to a single monolithic source would have made it really too
1517        unwieldy, quite apart from causing all the code to be include in a
1518        statically linked application, when only some functions are used. This is
1519        relevant even without the DFA addition now that patterns can be compiled in
1520        one application and matched in another.
1521    
1522        The downside of splitting up is that there have to be some external
1523        functions and data tables that are used internally in different modules of
1524        the library but which are not part of the API. These have all had their
1525        names changed to start with "_pcre_" so that they are unlikely to clash
1526        with other external names.
1527    
1528     4. Added an alternate matching function, pcre_dfa_exec(), which matches using
1529        a different (DFA) algorithm. Although it is slower than the original
1530        function, it does have some advantages for certain types of matching
1531        problem.
1532    
1533     5. Upgrades to pcretest in order to test the features of pcre_dfa_exec(),
1534        including restarting after a partial match.
1535    
1536     6. A patch for pcregrep that defines INVALID_FILE_ATTRIBUTES if it is not
1537        defined when compiling for Windows was sent to me. I have put it into the
1538        code, though I have no means of testing or verifying it.
1539    
1540     7. Added the pcre_refcount() auxiliary function.
1541    
1542     8. Added the PCRE_FIRSTLINE option. This constrains an unanchored pattern to
1543        match before or at the first newline in the subject string. In pcretest,
1544        the /f option on a pattern can be used to set this.
1545    
1546     9. A repeated \w when used in UTF-8 mode with characters greater than 256
1547        would behave wrongly. This has been present in PCRE since release 4.0.
1548    
1549    10. A number of changes to the pcregrep command:
1550    
1551        (a) Refactored how -x works; insert ^(...)$ instead of setting
1552            PCRE_ANCHORED and checking the length, in preparation for adding
1553            something similar for -w.
1554    
1555        (b) Added the -w (match as a word) option.
1556    
1557        (c) Refactored the way lines are read and buffered so as to have more
1558            than one at a time available.
1559    
1560        (d) Implemented a pcregrep test script.
1561    
1562        (e) Added the -M (multiline match) option. This allows patterns to match
1563            over several lines of the subject. The buffering ensures that at least
1564            8K, or the rest of the document (whichever is the shorter) is available
1565            for matching (and similarly the previous 8K for lookbehind assertions).
1566    
1567        (f) Changed the --help output so that it now says
1568    
1569              -w, --word-regex(p)
1570    
1571            instead of two lines, one with "regex" and the other with "regexp"
1572            because that confused at least one person since the short forms are the
1573            same. (This required a bit of code, as the output is generated
1574            automatically from a table. It wasn't just a text change.)
1575    
1576        (g) -- can be used to terminate pcregrep options if the next thing isn't an
1577            option but starts with a hyphen. Could be a pattern or a path name
1578            starting with a hyphen, for instance.
1579    
1580        (h) "-" can be given as a file name to represent stdin.
1581    
1582        (i) When file names are being printed, "(standard input)" is used for
1583            the standard input, for compatibility with GNU grep. Previously
1584            "<stdin>" was used.
1585    
1586        (j) The option --label=xxx can be used to supply a name to be used for
1587            stdin when file names are being printed. There is no short form.
1588    
1589        (k) Re-factored the options decoding logic because we are going to add
1590            two more options that take data. Such options can now be given in four
1591            different ways, e.g. "-fname", "-f name", "--file=name", "--file name".
1592    
1593        (l) Added the -A, -B, and -C options for requesting that lines of context
1594            around matches be printed.
1595    
1596        (m) Added the -L option to print the names of files that do not contain
1597            any matching lines, that is, the complement of -l.
1598    
1599        (n) The return code is 2 if any file cannot be opened, but pcregrep does
1600            continue to scan other files.
1601    
1602        (o) The -s option was incorrectly implemented. For compatibility with other
1603            greps, it now suppresses the error message for a non-existent or non-
1604            accessible file (but not the return code). There is a new option called
1605            -q that suppresses the output of matching lines, which was what -s was
1606            previously doing.
1607    
1608        (p) Added --include and --exclude options to specify files for inclusion
1609            and exclusion when recursing.
1610    
1611    11. The Makefile was not using the Autoconf-supported LDFLAGS macro properly.
1612        Hopefully, it now does.
1613    
1614    12. Missing cast in pcre_study().
1615    
1616    13. Added an "uninstall" target to the makefile.
1617    
1618    14. Replaced "extern" in the function prototypes in Makefile.in with
1619        "PCRE_DATA_SCOPE", which defaults to 'extern' or 'extern "C"' in the Unix
1620        world, but is set differently for Windows.
1621    
1622    15. Added a second compiling function called pcre_compile2(). The only
1623        difference is that it has an extra argument, which is a pointer to an
1624        integer error code. When there is a compile-time failure, this is set
1625        non-zero, in addition to the error test pointer being set to point to an
1626        error message. The new argument may be NULL if no error number is required
1627        (but then you may as well call pcre_compile(), which is now just a
1628        wrapper). This facility is provided because some applications need a
1629        numeric error indication, but it has also enabled me to tidy up the way
1630        compile-time errors are handled in the POSIX wrapper.
1631    
1632    16. Added VPATH=.libs to the makefile; this should help when building with one
1633        prefix path and installing with another. (Or so I'm told by someone who
1634        knows more about this stuff than I do.)
1635    
1636    17. Added a new option, REG_DOTALL, to the POSIX function regcomp(). This
1637        passes PCRE_DOTALL to the pcre_compile() function, making the "." character
1638        match everything, including newlines. This is not POSIX-compatible, but
1639        somebody wanted the feature. From pcretest it can be activated by using
1640        both the P and the s flags.
1641    
1642    18. AC_PROG_LIBTOOL appeared twice in Makefile.in. Removed one.
1643    
1644    19. libpcre.pc was being incorrectly installed as executable.
1645    
1646    20. A couple of places in pcretest check for end-of-line by looking for '\n';
1647        it now also looks for '\r' so that it will work unmodified on Windows.
1648    
1649    21. Added Google's contributed C++ wrapper to the distribution.
1650    
1651    22. Added some untidy missing memory free() calls in pcretest, to keep
1652        Electric Fence happy when testing.
1653    
1654    
1655    
1656    Version 5.0 13-Sep-04
1657    ---------------------
1658    
1659     1. Internal change: literal characters are no longer packed up into items
1660        containing multiple characters in a single byte-string. Each character
1661        is now matched using a separate opcode. However, there may be more than one
1662        byte in the character in UTF-8 mode.
1663    
1664     2. The pcre_callout_block structure has two new fields: pattern_position and
1665        next_item_length. These contain the offset in the pattern to the next match
1666        item, and its length, respectively.
1667    
1668     3. The PCRE_AUTO_CALLOUT option for pcre_compile() requests the automatic
1669        insertion of callouts before each pattern item. Added the /C option to
1670        pcretest to make use of this.
1671    
1672     4. On the advice of a Windows user, the lines
1673    
1674          #if defined(_WIN32) || defined(WIN32)
1675          _setmode( _fileno( stdout ), 0x8000 );
1676          #endif  /* defined(_WIN32) || defined(WIN32) */
1677    
1678        have been added to the source of pcretest. This apparently does useful
1679        magic in relation to line terminators.
1680    
1681     5. Changed "r" and "w" in the calls to fopen() in pcretest to "rb" and "wb"
1682        for the benefit of those environments where the "b" makes a difference.
1683    
1684     6. The icc compiler has the same options as gcc, but "configure" doesn't seem
1685        to know about it. I have put a hack into configure.in that adds in code
1686        to set GCC=yes if CC=icc. This seems to end up at a point in the
1687        generated configure script that is early enough to affect the setting of
1688        compiler options, which is what is needed, but I have no means of testing
1689        whether it really works. (The user who reported this had patched the
1690        generated configure script, which of course I cannot do.)
1691    
1692        LATER: After change 22 below (new libtool files), the configure script
1693        seems to know about icc (and also ecc). Therefore, I have commented out
1694        this hack in configure.in.
1695    
1696     7. Added support for pkg-config (2 patches were sent in).
1697    
1698     8. Negated POSIX character classes that used a combination of internal tables
1699        were completely broken. These were [[:^alpha:]], [[:^alnum:]], and
1700        [[:^ascii]]. Typically, they would match almost any characters. The other
1701        POSIX classes were not broken in this way.
1702    
1703     9. Matching the pattern "\b.*?" against "ab cd", starting at offset 1, failed
1704        to find the match, as PCRE was deluded into thinking that the match had to
1705        start at the start point or following a newline. The same bug applied to
1706        patterns with negative forward assertions or any backward assertions
1707        preceding ".*" at the start, unless the pattern required a fixed first
1708        character. This was a failing pattern: "(?!.bcd).*". The bug is now fixed.
1709    
1710    10. In UTF-8 mode, when moving forwards in the subject after a failed match
1711        starting at the last subject character, bytes beyond the end of the subject
1712        string were read.
1713    
1714    11. Renamed the variable "class" as "classbits" to make life easier for C++
1715        users. (Previously there was a macro definition, but it apparently wasn't
1716        enough.)
1717    
1718    12. Added the new field "tables" to the extra data so that tables can be passed
1719        in at exec time, or the internal tables can be re-selected. This allows
1720        a compiled regex to be saved and re-used at a later time by a different
1721        program that might have everything at different addresses.
1722    
1723    13. Modified the pcre-config script so that, when run on Solaris, it shows a
1724        -R library as well as a -L library.
1725    
1726    14. The debugging options of pcretest (-d on the command line or D on a
1727        pattern) showed incorrect output for anything following an extended class
1728        that contained multibyte characters and which was followed by a quantifier.
1729    
1730    15. Added optional support for general category Unicode character properties
1731        via the \p, \P, and \X escapes. Unicode property support implies UTF-8
1732        support. It adds about 90K to the size of the library. The meanings of the
1733        inbuilt class escapes such as \d and \s have NOT been changed.
1734    
1735    16. Updated pcredemo.c to include calls to free() to release the memory for the
1736        compiled pattern.
1737    
1738    17. The generated file chartables.c was being created in the source directory
1739        instead of in the building directory. This caused the build to fail if the
1740        source directory was different from the building directory, and was
1741        read-only.
1742    
1743    18. Added some sample Win commands from Mark Tetrode into the NON-UNIX-USE
1744        file. No doubt somebody will tell me if they don't make sense... Also added
1745        Dan Mooney's comments about building on OpenVMS.
1746    
1747    19. Added support for partial matching via the PCRE_PARTIAL option for
1748        pcre_exec() and the \P data escape in pcretest.
1749    
1750    20. Extended pcretest with 3 new pattern features:
1751    
1752        (i)   A pattern option of the form ">rest-of-line" causes pcretest to
1753              write the compiled pattern to the file whose name is "rest-of-line".
1754              This is a straight binary dump of the data, with the saved pointer to
1755              the character tables forced to be NULL. The study data, if any, is
1756              written too. After writing, pcretest reads a new pattern.
1757    
1758        (ii)  If, instead of a pattern, "<rest-of-line" is given, pcretest reads a
1759              compiled pattern from the given file. There must not be any
1760              occurrences of "<" in the file name (pretty unlikely); if there are,
1761              pcretest will instead treat the initial "<" as a pattern delimiter.
1762              After reading in the pattern, pcretest goes on to read data lines as
1763              usual.
1764    
1765        (iii) The F pattern option causes pcretest to flip the bytes in the 32-bit
1766              and 16-bit fields in a compiled pattern, to simulate a pattern that
1767              was compiled on a host of opposite endianness.
1768    
1769    21. The pcre-exec() function can now cope with patterns that were compiled on
1770        hosts of opposite endianness, with this restriction:
1771    
1772          As for any compiled expression that is saved and used later, the tables
1773          pointer field cannot be preserved; the extra_data field in the arguments
1774          to pcre_exec() should be used to pass in a tables address if a value
1775          other than the default internal tables were used at compile time.
1776    
1777    22. Calling pcre_exec() with a negative value of the "ovecsize" parameter is
1778        now diagnosed as an error. Previously, most of the time, a negative number
1779        would have been treated as zero, but if in addition "ovector" was passed as
1780        NULL, a crash could occur.
1781    
1782    23. Updated the files ltmain.sh, config.sub, config.guess, and aclocal.m4 with
1783        new versions from the libtool 1.5 distribution (the last one is a copy of
1784        a file called libtool.m4). This seems to have fixed the need to patch
1785        "configure" to support Darwin 1.3 (which I used to do). However, I still
1786        had to patch ltmain.sh to ensure that ${SED} is set (it isn't on my
1787        workstation).
1788    
1789    24. Changed the PCRE licence to be the more standard "BSD" licence.
1790    
1791    
1792    Version 4.5 01-Dec-03
1793    ---------------------
1794    
1795     1. There has been some re-arrangement of the code for the match() function so
1796        that it can be compiled in a version that does not call itself recursively.
1797        Instead, it keeps those local variables that need separate instances for
1798        each "recursion" in a frame on the heap, and gets/frees frames whenever it
1799        needs to "recurse". Keeping track of where control must go is done by means
1800        of setjmp/longjmp. The whole thing is implemented by a set of macros that
1801        hide most of the details from the main code, and operates only if
1802        NO_RECURSE is defined while compiling pcre.c. If PCRE is built using the
1803        "configure" mechanism, "--disable-stack-for-recursion" turns on this way of
1804        operating.
1805    
1806        To make it easier for callers to provide specially tailored get/free
1807        functions for this usage, two new functions, pcre_stack_malloc, and
1808        pcre_stack_free, are used. They are always called in strict stacking order,
1809        and the size of block requested is always the same.
1810    
1811        The PCRE_CONFIG_STACKRECURSE info parameter can be used to find out whether
1812        PCRE has been compiled to use the stack or the heap for recursion. The
1813        -C option of pcretest uses this to show which version is compiled.
1814    
1815        A new data escape \S, is added to pcretest; it causes the amounts of store
1816        obtained and freed by both kinds of malloc/free at match time to be added
1817        to the output.
1818    
1819     2. Changed the locale test to use "fr_FR" instead of "fr" because that's
1820        what's available on my current Linux desktop machine.
1821    
1822     3. When matching a UTF-8 string, the test for a valid string at the start has
1823        been extended. If start_offset is not zero, PCRE now checks that it points
1824        to a byte that is the start of a UTF-8 character. If not, it returns
1825        PCRE_ERROR_BADUTF8_OFFSET (-11). Note: the whole string is still checked;
1826        this is necessary because there may be backward assertions in the pattern.
1827        When matching the same subject several times, it may save resources to use
1828        PCRE_NO_UTF8_CHECK on all but the first call if the string is long.
1829    
1830     4. The code for checking the validity of UTF-8 strings has been tightened so
1831        that it rejects (a) strings containing 0xfe or 0xff bytes and (b) strings
1832        containing "overlong sequences".
1833    
1834     5. Fixed a bug (appearing twice) that I could not find any way of exploiting!
1835        I had written "if ((digitab[*p++] && chtab_digit) == 0)" where the "&&"
1836        should have been "&", but it just so happened that all the cases this let
1837        through by mistake were picked up later in the function.
1838    
1839     6. I had used a variable called "isblank" - this is a C99 function, causing
1840        some compilers to warn. To avoid this, I renamed it (as "blankclass").
1841    
1842     7. Cosmetic: (a) only output another newline at the end of pcretest if it is
1843        prompting; (b) run "./pcretest /dev/null" at the start of the test script
1844        so the version is shown; (c) stop "make test" echoing "./RunTest".
1845    
1846     8. Added patches from David Burgess to enable PCRE to run on EBCDIC systems.
1847    
1848     9. The prototype for memmove() for systems that don't have it was using
1849        size_t, but the inclusion of the header that defines size_t was later. I've
1850        moved the #includes for the C headers earlier to avoid this.
1851    
1852    10. Added some adjustments to the code to make it easier to compiler on certain
1853        special systems:
1854    
1855          (a) Some "const" qualifiers were missing.
1856          (b) Added the macro EXPORT before all exported functions; by default this
1857              is defined to be empty.
1858          (c) Changed the dftables auxiliary program (that builds chartables.c) so
1859              that it reads its output file name as an argument instead of writing
1860              to the standard output and assuming this can be redirected.
1861    
1862    11. In UTF-8 mode, if a recursive reference (e.g. (?1)) followed a character
1863        class containing characters with values greater than 255, PCRE compilation
1864        went into a loop.
1865    
1866    12. A recursive reference to a subpattern that was within another subpattern
1867        that had a minimum quantifier of zero caused PCRE to crash. For example,
1868        (x(y(?2))z)? provoked this bug with a subject that got as far as the
1869        recursion. If the recursively-called subpattern itself had a zero repeat,
1870        that was OK.
1871    
1872    13. In pcretest, the buffer for reading a data line was set at 30K, but the
1873        buffer into which it was copied (for escape processing) was still set at
1874        1024, so long lines caused crashes.
1875    
1876    14. A pattern such as /[ab]{1,3}+/ failed to compile, giving the error
1877        "internal error: code overflow...". This applied to any character class
1878        that was followed by a possessive quantifier.
1879    
1880    15. Modified the Makefile to add libpcre.la as a prerequisite for
1881        libpcreposix.la because I was told this is needed for a parallel build to
1882        work.
1883    
1884    16. If a pattern that contained .* following optional items at the start was
1885        studied, the wrong optimizing data was generated, leading to matching
1886        errors. For example, studying /[ab]*.*c/ concluded, erroneously, that any
1887        matching string must start with a or b or c. The correct conclusion for
1888        this pattern is that a match can start with any character.
1889    
1890    
1891    Version 4.4 13-Aug-03
1892    ---------------------
1893    
1894     1. In UTF-8 mode, a character class containing characters with values between
1895        127 and 255 was not handled correctly if the compiled pattern was studied.
1896        In fixing this, I have also improved the studying algorithm for such
1897        classes (slightly).
1898    
1899     2. Three internal functions had redundant arguments passed to them. Removal
1900        might give a very teeny performance improvement.
1901    
1902     3. Documentation bug: the value of the capture_top field in a callout is *one
1903        more than* the number of the hightest numbered captured substring.
1904    
1905     4. The Makefile linked pcretest and pcregrep with -lpcre, which could result
1906        in incorrectly linking with a previously installed version. They now link
1907        explicitly with libpcre.la.
1908    
1909     5. configure.in no longer needs to recognize Cygwin specially.
1910    
1911     6. A problem in pcre.in for Windows platforms is fixed.
1912    
1913     7. If a pattern was successfully studied, and the -d (or /D) flag was given to
1914        pcretest, it used to include the size of the study block as part of its
1915        output. Unfortunately, the structure contains a field that has a different
1916        size on different hardware architectures. This meant that the tests that
1917        showed this size failed. As the block is currently always of a fixed size,
1918        this information isn't actually particularly useful in pcretest output, so
1919        I have just removed it.
1920    
1921     8. Three pre-processor statements accidentally did not start in column 1.
1922        Sadly, there are *still* compilers around that complain, even though
1923        standard C has not required this for well over a decade. Sigh.
1924    
1925     9. In pcretest, the code for checking callouts passed small integers in the
1926        callout_data field, which is a void * field. However, some picky compilers
1927        complained about the casts involved for this on 64-bit systems. Now
1928        pcretest passes the address of the small integer instead, which should get
1929        rid of the warnings.
1930    
1931    10. By default, when in UTF-8 mode, PCRE now checks for valid UTF-8 strings at
1932        both compile and run time, and gives an error if an invalid UTF-8 sequence
1933        is found. There is a option for disabling this check in cases where the
1934        string is known to be correct and/or the maximum performance is wanted.
1935    
1936    11. In response to a bug report, I changed one line in Makefile.in from
1937    
1938            -Wl,--out-implib,.libs/lib@WIN_PREFIX@pcreposix.dll.a \
1939        to
1940            -Wl,--out-implib,.libs/@WIN_PREFIX@libpcreposix.dll.a \
1941    
1942        to look similar to other lines, but I have no way of telling whether this
1943        is the right thing to do, as I do not use Windows. No doubt I'll get told
1944        if it's wrong...
1945    
1946    
1947    Version 4.3 21-May-03
1948    ---------------------
1949    
1950    1. Two instances of @WIN_PREFIX@ omitted from the Windows targets in the
1951       Makefile.
1952    
1953    2. Some refactoring to improve the quality of the code:
1954    
1955       (i)   The utf8_table... variables are now declared "const".
1956    
1957       (ii)  The code for \cx, which used the "case flipping" table to upper case
1958             lower case letters, now just substracts 32. This is ASCII-specific,
1959             but the whole concept of \cx is ASCII-specific, so it seems
1960             reasonable.
1961    
1962       (iii) PCRE was using its character types table to recognize decimal and
1963             hexadecimal digits in the pattern. This is silly, because it handles
1964             only 0-9, a-f, and A-F, but the character types table is locale-
1965             specific, which means strange things might happen. A private
1966             table is now used for this - though it costs 256 bytes, a table is
1967             much faster than multiple explicit tests. Of course, the standard
1968             character types table is still used for matching digits in subject
1969             strings against \d.
1970    
1971       (iv)  Strictly, the identifier ESC_t is reserved by POSIX (all identifiers
1972             ending in _t are). So I've renamed it as ESC_tee.
1973    
1974    3. The first argument for regexec() in the POSIX wrapper should have been
1975       defined as "const".
1976    
1977    4. Changed pcretest to use malloc() for its buffers so that they can be
1978       Electric Fenced for debugging.
1979    
1980    5. There were several places in the code where, in UTF-8 mode, PCRE would try
1981       to read one or more bytes before the start of the subject string. Often this
1982       had no effect on PCRE's behaviour, but in some circumstances it could
1983       provoke a segmentation fault.
1984    
1985    6. A lookbehind at the start of a pattern in UTF-8 mode could also cause PCRE
1986       to try to read one or more bytes before the start of the subject string.
1987    
1988    7. A lookbehind in a pattern matched in non-UTF-8 mode on a PCRE compiled with
1989       UTF-8 support could misbehave in various ways if the subject string
1990       contained bytes with the 0x80 bit set and the 0x40 bit unset in a lookbehind
1991       area. (PCRE was not checking for the UTF-8 mode flag, and trying to move
1992       back over UTF-8 characters.)
1993    
1994    
1995    Version 4.2 14-Apr-03
1996    ---------------------
1997    
1998    1. Typo "#if SUPPORT_UTF8" instead of "#ifdef SUPPORT_UTF8" fixed.
1999    
2000    2. Changes to the building process, supplied by Ronald Landheer-Cieslak
2001         [ON_WINDOWS]: new variable, "#" on non-Windows platforms
2002         [NOT_ON_WINDOWS]: new variable, "#" on Windows platforms
2003         [WIN_PREFIX]: new variable, "cyg" for Cygwin
2004         * Makefile.in: use autoconf substitution for OBJEXT, EXEEXT, BUILD_OBJEXT
2005           and BUILD_EXEEXT
2006         Note: automatic setting of the BUILD variables is not yet working
2007         set CPPFLAGS and BUILD_CPPFLAGS (but don't use yet) - should be used at
2008           compile-time but not at link-time
2009         [LINK]: use for linking executables only
2010         make different versions for Windows and non-Windows
2011         [LINKLIB]: new variable, copy of UNIX-style LINK, used for linking
2012           libraries
2013         [LINK_FOR_BUILD]: new variable
2014         [OBJEXT]: use throughout
2015         [EXEEXT]: use throughout
2016         <winshared>: new target
2017         <wininstall>: new target
2018         <dftables.o>: use native compiler
2019         <dftables>: use native linker
2020         <install>: handle Windows platform correctly
2021         <clean>: ditto
2022         <check>: ditto
2023         copy DLL to top builddir before testing
2024    
2025       As part of these changes, -no-undefined was removed again. This was reported
2026       to give trouble on HP-UX 11.0, so getting rid of it seems like a good idea
2027       in any case.
2028    
2029    3. Some tidies to get rid of compiler warnings:
2030    
2031       . In the match_data structure, match_limit was an unsigned long int, whereas
2032         match_call_count was an int. I've made them both unsigned long ints.
2033    
2034       . In pcretest the fact that a const uschar * doesn't automatically cast to
2035         a void * provoked a warning.
2036    
2037       . Turning on some more compiler warnings threw up some "shadow" variables
2038         and a few more missing casts.
2039    
2040    4. If PCRE was complied with UTF-8 support, but called without the PCRE_UTF8
2041       option, a class that contained a single character with a value between 128
2042       and 255 (e.g. /[\xFF]/) caused PCRE to crash.
2043    
2044    5. If PCRE was compiled with UTF-8 support, but called without the PCRE_UTF8
2045       option, a class that contained several characters, but with at least one
2046       whose value was between 128 and 255 caused PCRE to crash.
2047    
2048    
2049    Version 4.1 12-Mar-03
2050    ---------------------
2051    
2052    1. Compiling with gcc -pedantic found a couple of places where casts were
2053    needed, and a string in dftables.c that was longer than standard compilers are
2054    required to support.
2055    
2056    2. Compiling with Sun's compiler found a few more places where the code could
2057    be tidied up in order to avoid warnings.
2058    
2059    3. The variables for cross-compiling were called HOST_CC and HOST_CFLAGS; the
2060    first of these names is deprecated in the latest Autoconf in favour of the name
2061    CC_FOR_BUILD, because "host" is typically used to mean the system on which the
2062    compiled code will be run. I can't find a reference for HOST_CFLAGS, but by
2063    analogy I have changed it to CFLAGS_FOR_BUILD.
2064    
2065    4. Added -no-undefined to the linking command in the Makefile, because this is
2066    apparently helpful for Windows. To make it work, also added "-L. -lpcre" to the
2067    linking step for the pcreposix library.
2068    
2069    5. PCRE was failing to diagnose the case of two named groups with the same
2070    name.
2071    
2072    6. A problem with one of PCRE's optimizations was discovered. PCRE remembers a
2073    literal character that is needed in the subject for a match, and scans along to
2074    ensure that it is present before embarking on the full matching process. This
2075    saves time in cases of nested unlimited repeats that are never going to match.
2076    Problem: the scan can take a lot of time if the subject is very long (e.g.
2077    megabytes), thus penalizing straightforward matches. It is now done only if the
2078    amount of subject to be scanned is less than 1000 bytes.
2079    
2080    7. A lesser problem with the same optimization is that it was recording the
2081    first character of an anchored pattern as "needed", thus provoking a search
2082    right along the subject, even when the first match of the pattern was going to
2083    fail. The "needed" character is now not set for anchored patterns, unless it
2084    follows something in the pattern that is of non-fixed length. Thus, it still
2085    fulfils its original purpose of finding quick non-matches in cases of nested
2086    unlimited repeats, but isn't used for simple anchored patterns such as /^abc/.
2087    
2088    
2089    Version 4.0 17-Feb-03
2090    ---------------------
2091    
2092  1. If a comment in an extended regex that started immediately after a meta-item  1. If a comment in an extended regex that started immediately after a meta-item
2093  extended to the end of string, PCRE compiled incorrect data. This could lead to  extended to the end of string, PCRE compiled incorrect data. This could lead to

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