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

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