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

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