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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 285 by ph10, Wed Dec 12 17:03:50 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.5 12-Nov-07
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
54    
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
68    
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
73    
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
78    
79    14. The pattern (?=something)(?R) was not being diagnosed as a potentially
80        infinitely looping recursion. The bug was that positive lookaheads were not
81        being skipped when checking for a possible empty match (negative lookaheads
82        and both kinds of lookbehind were skipped).
83    
84    15. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
85        inclusion of <windows.h> to before rather than after the definition of
86        INVALID_FILE_ATTRIBUTES (patch from David Byron).
87    
88    16. Specifying a possessive quantifier with a specific limit for a Unicode
89        character property caused pcre_compile() to compile bad code, which led at
90        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
91        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
92        caused the error; without that there was no problem.
93    
94    
95    Version 7.4 21-Sep-07
96    ---------------------
97    
98    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
99        means that a class such as [\s] counted as "explicit reference to CR or
100        LF". That isn't really right - the whole point of the change was to try to
101        help when there was an actual mention of one of the two characters. So now
102        the change happens only if \r or \n (or a literal CR or LF) character is
103        encountered.
104    
105    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
106        of both had grown to the point where there were only 3 bits left.
107        Fortunately, there was spare space in the data structure, and so I have
108        moved the internal flags into a new 16-bit field to free up more option
109        bits.
110    
111    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
112        but did not set the internal JCHANGED flag - either of these is enough to
113        control the way the "get" function works - but the PCRE_INFO_JCHANGED
114        facility is supposed to tell if (?J) was ever used, so now (?J) at the
115        start sets both bits.
116    
117    4.  Added options (at build time, compile time, exec time) to change \R from
118        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
119    
120    5.  doc/pcresyntax.html was missing from the distribution.
121    
122    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
123        compatibility, even though it is no longer used.
124    
125    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
126        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
127        windows.h file is present (where different names are used). [This was
128        reversed later after testing - see 16 below.]
129    
130    8.  Changed all #include <config.h> to #include "config.h". There were also
131        some further <pcre.h> cases that I changed to "pcre.h".
132    
133    9.  When pcregrep was used with the --colour option, it missed the line ending
134        sequence off the lines that it output.
135    
136    10. It was pointed out to me that arrays of string pointers cause lots of
137        relocations when a shared library is dynamically loaded. A technique of
138        using a single long string with a table of offsets can drastically reduce
139        these. I have refactored PCRE in four places to do this. The result is
140        dramatic:
141    
142          Originally:                          290
143          After changing UCP table:            187
144          After changing error message table:   43
145          After changing table of "verbs"       36
146          After changing table of Posix names   22
147    
148        Thanks to the folks working on Gregex for glib for this insight.
149    
150    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
151        unicode-properties was also set.
152    
153    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
154    
155    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
156        checked only for CRLF.
157    
158    14. Added casts to pcretest.c to avoid compiler warnings.
159    
160    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
161    
162    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
163        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
164        entirely. This removes changes made in 7 above.
165    
166    17. The CMake files have been updated, and there is now more information about
167        building with CMake in the NON-UNIX-USE document.
168    
169    
170    Version 7.3 28-Aug-07
171    ---------------------
172    
173     1. In the rejigging of the build system that eventually resulted in 7.1, the
174        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
175        brackets there is not right, since it causes compilers to look for an
176        installed pcre.h, not the version that is in the source that is being
177        compiled (which of course may be different). I have changed it back to:
178    
179          #include "pcre.h"
180    
181        I have a vague recollection that the change was concerned with compiling in
182        different directories, but in the new build system, that is taken care of
183        by the VPATH setting the Makefile.
184    
185     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
186        when the subject happened to end in the byte 0x85 (e.g. if the last
187        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
188        characters but of course it shouldn't be taken as a newline when it is part
189        of another character. The bug was that, for an unlimited repeat of . in
190        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
191        characters when looking for a newline.
192    
193     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
194    
195     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
196        in debug output.
197    
198     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
199        long printing in the pcrecpp unittest when running under MinGW.
200    
201     6. ESC_K was left out of the EBCDIC table.
202    
203     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
204        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
205        limit also applies to "virtual nesting" when a pattern is recursive, and in
206        this case 1000 isn't so big. I have been able to remove this limit at the
207        expense of backing off one optimization in certain circumstances. Normally,
208        when pcre_exec() would call its internal match() function recursively and
209        immediately return the result unconditionally, it uses a "tail recursion"
210        feature to save stack. However, when a subpattern that can match an empty
211        string has an unlimited repetition quantifier, it no longer makes this
212        optimization. That gives it a stack frame in which to save the data for
213        checking that an empty string has been matched. Previously this was taken
214        from the 1000-entry workspace that had been reserved. So now there is no
215        explicit limit, but more stack is used.
216    
217     8. Applied Daniel's patches to solve problems with the import/export magic
218        syntax that is required for Windows, and which was going wrong for the
219        pcreposix and pcrecpp parts of the library. These were overlooked when this
220        problem was solved for the main library.
221    
222     9. There were some crude static tests to avoid integer overflow when computing
223        the size of patterns that contain repeated groups with explicit upper
224        limits. As the maximum quantifier is 65535, the maximum group length was
225        set at 30,000 so that the product of these two numbers did not overflow a
226        32-bit integer. However, it turns out that people want to use groups that
227        are longer than 30,000 bytes (though not repeat them that many times).
228        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
229        made it possible to implement the integer overflow checks in a much more
230        dynamic way, which I have now done. The artificial limitation on group
231        length has been removed - we now have only the limit on the total length of
232        the compiled pattern, which depends on the LINK_SIZE setting.
233    
234    10. Fixed a bug in the documentation for get/copy named substring when
235        duplicate names are permitted. If none of the named substrings are set, the
236        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
237        empty string.
238    
239    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
240        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
241        because the ] is interpreted as the first data character and the
242        terminating ] is not found. PCRE has been made compatible with Perl in this
243        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
244        cause memory overwriting.
245    
246    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
247        string has been matched (to stop an infinite loop). It was not recognizing
248        a conditional subpattern that could match an empty string if that
249        subpattern was within another subpattern. For example, it looped when
250        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
251        condition was not nested. This bug has been fixed.
252    
253    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
254        past the start of the subject in the presence of bytes with the top bit
255        set, for example "\x8aBCD".
256    
257    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
258        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
259    
260    14. Optimized (?!) to (*FAIL).
261    
262    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
263        This restricts code points to be within the range 0 to 0x10FFFF, excluding
264        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
265        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
266        does: it's just the validity check that is more restrictive.
267    
268    16. Inserted checks for integer overflows during escape sequence (backslash)
269        processing, and also fixed erroneous offset values for syntax errors during
270        backslash processing.
271    
272    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
273        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
274    
275    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
276        caused an overrun.
277    
278    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
279        something other than just ASCII characters) inside a group that had an
280        unlimited repeat caused a loop at compile time (while checking to see
281        whether the group could match an empty string).
282    
283    20. Debugging a pattern containing \p or \P could cause a crash. For example,
284        [\P{Any}] did so. (Error in the code for printing property names.)
285    
286    21. An orphan \E inside a character class could cause a crash.
287    
288    22. A repeated capturing bracket such as (A)? could cause a wild memory
289        reference during compilation.
290    
291    23. There are several functions in pcre_compile() that scan along a compiled
292        expression for various reasons (e.g. to see if it's fixed length for look
293        behind). There were bugs in these functions when a repeated \p or \P was
294        present in the pattern. These operators have additional parameters compared
295        with \d, etc, and these were not being taken into account when moving along
296        the compiled data. Specifically:
297    
298        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
299            length.
300    
301        (b) An item such as \pL+ within a repeated group could cause crashes or
302            loops.
303    
304        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
305            "reference to non-existent subpattern" error.
306    
307        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
308    
309    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
310        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
311    
312    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
313    
314    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
315        character were causing crashes (broken optimization).
316    
317    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
318        \p or \P) caused a compile-time loop.
319    
320    28. More problems have arisen in unanchored patterns when CRLF is a valid line
321        break. For example, the unstudied pattern [\r\n]A does not match the string
322        "\r\nA" because change 7.0/46 below moves the current point on by two
323        characters after failing to match at the start. However, the pattern \nA
324        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
325        the same is true. There doesn't seem any very clean way out of this, but
326        what I have chosen to do makes the common cases work: PCRE now takes note
327        of whether there can be an explicit match for \r or \n anywhere in the
328        pattern, and if so, 7.0/46 no longer applies. As part of this change,
329        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
330        pattern has explicit CR or LF references.
331    
332    29. Added (*CR) etc for changing newline setting at start of pattern.
333    
334    
335    Version 7.2 19-Jun-07
336    ---------------------
337    
338     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
339        which is apparently normally available under Windows.
340    
341     2. Re-jig the pcregrep tests with different newline settings in an attempt
342        to make them independent of the local environment's newline setting.
343    
344     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
345    
346     4. Some of the "internals" tests were previously cut out when the link size
347        was not 2, because the output contained actual offsets. The recent new
348        "Z" feature of pcretest means that these can be cut out, making the tests
349        usable with all link sizes.
350    
351     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
352        stack recursion. This gives a massive performance boost under BSD, but just
353        a small improvement under Linux. However, it saves one field in the frame
354        in all cases.
355    
356     6. Added more features from the forthcoming Perl 5.10:
357    
358        (a) (?-n) (where n is a string of digits) is a relative subroutine or
359            recursion call. It refers to the nth most recently opened parentheses.
360    
361        (b) (?+n) is also a relative subroutine call; it refers to the nth next
362            to be opened parentheses.
363    
364        (c) Conditions that refer to capturing parentheses can be specified
365            relatively, for example, (?(-2)... or (?(+3)...
366    
367        (d) \K resets the start of the current match so that everything before
368            is not part of it.
369    
370        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
371    
372        (f) \g{name} is another synonym - part of Perl 5.10's unification of
373            reference syntax.
374    
375        (g) (?| introduces a group in which the numbering of parentheses in each
376            alternative starts with the same number.
377    
378        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
379    
380     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
381        PCRE_INFO_JCHANGED.
382    
383     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
384        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
385        for detecting groups that can match an empty string.
386    
387     9. A pattern with a very large number of alternatives (more than several
388        hundred) was running out of internal workspace during the pre-compile
389        phase, where pcre_compile() figures out how much memory will be needed. A
390        bit of new cunning has reduced the workspace needed for groups with
391        alternatives. The 1000-alternative test pattern now uses 12 bytes of
392        workspace instead of running out of the 4096 that are available.
393    
394    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
395    
396    11. Applied patch from Google to remove an optimization that didn't quite work.
397        The report of the bug said:
398    
399          pcrecpp::RE("a*").FullMatch("aaa") matches, while
400          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
401          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
402    
403    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
404        it matched the wrong number of bytes.
405    
406    
407    Version 7.1 24-Apr-07
408    ---------------------
409    
410     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
411        that is more "standard", making use of automake and other Autotools. There
412        is some re-arrangement of the files and adjustment of comments consequent
413        on this.
414    
415     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
416        for recursive directory scanning broke on some systems because the files
417        are not scanned in any specific order and on different systems the order
418        was different. A call to "sort" has been inserted into RunGrepTest for the
419        approprate test as a short-term fix. In the longer term there may be an
420        alternative.
421    
422     3. I had an email from Eric Raymond about problems translating some of PCRE's
423        man pages to HTML (despite the fact that I distribute HTML pages, some
424        people do their own conversions for various reasons). The problems
425        concerned the use of low-level troff macros .br and .in. I have therefore
426        removed all such uses from the man pages (some were redundant, some could
427        be replaced by .nf/.fi pairs). The 132html script that I use to generate
428        HTML has been updated to handle .nf/.fi and to complain if it encounters
429        .br or .in.
430    
431     4. Updated comments in configure.ac that get placed in config.h.in and also
432        arranged for config.h to be included in the distribution, with the name
433        config.h.generic, for the benefit of those who have to compile without
434        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
435    
436     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
437        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
438        makevp.bat for the current PCRE, using the additional files
439        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
440    
441     6. A Windows user reported a minor discrepancy with test 2, which turned out
442        to be caused by a trailing space on an input line that had got lost in his
443        copy. The trailing space was an accident, so I've just removed it.
444    
445     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
446        that is needed.
447    
448     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
449        as "const" (a) because they are and (b) because it helps the PHP
450        maintainers who have recently made a script to detect big data structures
451        in the php code that should be moved to the .rodata section. I remembered
452        to update Builducptable as well, so it won't revert if ucptable.h is ever
453        re-created.
454    
455     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
456        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
457        order to be able to cut out the UTF-8 tables in the latter when UTF-8
458        support is not required. This saves 1.5-2K of code, which is important in
459        some applications.
460    
461        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
462        so as not to refer to the tables, even though these functions will never be
463        called when UTF-8 support is disabled. Otherwise there are problems with a
464        shared library.
465    
466    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
467    
468        (a) It was defining its arguments as char * instead of void *.
469    
470        (b) It was assuming that all moves were upwards in memory; this was true
471            a long time ago when I wrote it, but is no longer the case.
472    
473        The emulated memove() is provided for those environments that have neither
474        memmove() nor bcopy(). I didn't think anyone used it these days, but that
475        is clearly not the case, as these two bugs were recently reported.
476    
477    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
478        and Detrail to create the HTML documentation, the .txt form of the man
479        pages, and it removes trailing spaces from listed files. It also creates
480        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
481        case, it wraps all the #defines with #ifndefs. This script should be run
482        before "make dist".
483    
484    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
485        with Unicode property support.
486    
487        (a) For a maximizing quantifier, if the two different cases of the
488            character were of different lengths in their UTF-8 codings (there are
489            some cases like this - I found 11), and the matching function had to
490            back up over a mixture of the two cases, it incorrectly assumed they
491            were both the same length.
492    
493        (b) When PCRE was configured to use the heap rather than the stack for
494            recursion during matching, it was not correctly preserving the data for
495            the other case of a UTF-8 character when checking ahead for a match
496            while processing a minimizing repeat. If the check also involved
497            matching a wide character, but failed, corruption could cause an
498            erroneous result when trying to check for a repeat of the original
499            character.
500    
501    13. Some tidying changes to the testing mechanism:
502    
503        (a) The RunTest script now detects the internal link size and whether there
504            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
505            values substituted by "configure". (The RunGrepTest script already did
506            this for UTF-8.) The configure.ac script no longer substitutes the
507            relevant variables.
508    
509        (b) The debugging options /B and /D in pcretest show the compiled bytecode
510            with length and offset values. This means that the output is different
511            for different internal link sizes. Test 2 is skipped for link sizes
512            other than 2 because of this, bypassing the problem. Unfortunately,
513            there was also a test in test 3 (the locale tests) that used /B and
514            failed for link sizes other than 2. Rather than cut the whole test out,
515            I have added a new /Z option to pcretest that replaces the length and
516            offset values with spaces. This is now used to make test 3 independent
517            of link size. (Test 2 will be tidied up later.)
518    
519    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
520        segmentation fault instead of returning the appropriate error message.
521    
522    15. In multiline mode when the newline sequence was set to "any", the pattern
523        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
524        This doesn't seem right; it now treats the CRLF combination as the line
525        ending, and so does not match in that case. It's only a pattern such as ^$
526        that would hit this one: something like ^ABC$ would have failed after \r
527        and then tried again after \r\n.
528    
529    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
530        in an attempt to make files that differ only in their line terminators
531        compare equal. This works on Linux.
532    
533    17. Under certain error circumstances pcregrep might try to free random memory
534        as it exited. This is now fixed, thanks to valgrind.
535    
536    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
537        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
538        was because its rules for how to advance for /g after matching an empty
539        string at the end of a line did not allow for this case. They now check for
540        it specially.
541    
542    20. pcretest is supposed to handle patterns and data of any length, by
543        extending its buffers when necessary. It was getting this wrong when the
544        buffer for a data line had to be extended.
545    
546    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
547        CRLF as a newline sequence.
548    
549    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
550        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
551        I have nevertheless tidied it up.
552    
553    23. Added some casts to kill warnings from HP-UX ia64 compiler.
554    
555    24. Added a man page for pcre-config.
556    
557    
558    Version 7.0 19-Dec-06
559    ---------------------
560    
561     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
562        moving to gcc 4.1.1.
563    
564     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
565        sys/time.h, which is documented as needed for this function. It doesn't
566        seem to matter on Linux, but it showed up on some releases of OS X.
567    
568     3. It seems that there are systems where bytes whose values are greater than
569        127 match isprint() in the "C" locale. The "C" locale should be the
570        default when a C program starts up. In most systems, only ASCII printing
571        characters match isprint(). This difference caused the output from pcretest
572        to vary, making some of the tests fail. I have changed pcretest so that:
573    
574        (a) When it is outputting text in the compiled version of a pattern, bytes
575            other than 32-126 are always shown as hex escapes.
576    
577        (b) When it is outputting text that is a matched part of a subject string,
578            it does the same, unless a different locale has been set for the match
579            (using the /L modifier). In this case, it uses isprint() to decide.
580    
581     4. Fixed a major bug that caused incorrect computation of the amount of memory
582        required for a compiled pattern when options that changed within the
583        pattern affected the logic of the preliminary scan that determines the
584        length. The relevant options are -x, and -i in UTF-8 mode. The result was
585        that the computed length was too small. The symptoms of this bug were
586        either the PCRE error "internal error: code overflow" from pcre_compile(),
587        or a glibc crash with a message such as "pcretest: free(): invalid next
588        size (fast)". Examples of patterns that provoked this bug (shown in
589        pcretest format) are:
590    
591          /(?-x: )/x
592          /(?x)(?-x: \s*#\s*)/
593          /((?i)[\x{c0}])/8
594          /(?i:[\x{c0}])/8
595    
596        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
597        is now done differently.
598    
599     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
600        wrapper classes; (b) implement a new function in the C++ scanner that is
601        more efficient than the old way of doing things because it avoids levels of
602        recursion in the regex matching; (c) add a paragraph to the documentation
603        for the FullMatch() function.
604    
605     6. The escape sequence \n was being treated as whatever was defined as
606        "newline". Not only was this contrary to the documentation, which states
607        that \n is character 10 (hex 0A), but it also went horribly wrong when
608        "newline" was defined as CRLF. This has been fixed.
609    
610     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
611        was being set to -1 for the "end of line" case (supposedly a value that no
612        character can have). Though this value is never used (the check for end of
613        line is "zero bytes in current character"), it caused compiler complaints.
614        I've changed it to 0xffffffff.
615    
616     8. In pcre_version.c, the version string was being built by a sequence of
617        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
618        string (as it is for production releases) called a macro with an empty
619        argument. The C standard says the result of this is undefined. The gcc
620        compiler treats it as an empty string (which was what was wanted) but it is
621        reported that Visual C gives an error. The source has been hacked around to
622        avoid this problem.
623    
624     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
625        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
626        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
627        of them did).
628    
629    10. Originally, pcretest opened its input and output without "b"; then I was
630        told that "b" was needed in some environments, so it was added for release
631        5.0 to both the input and output. (It makes no difference on Unix-like
632        systems.) Later I was told that it is wrong for the input on Windows. I've
633        now abstracted the modes into two macros, to make it easier to fiddle with
634        them, and removed "b" from the input mode under Windows.
635    
636    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
637    
638    12. Added -help and --help to pcretest as an official way of being reminded
639        of the options.
640    
641    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
642        and pcrecpp.cc because they annoy compilers at high warning levels.
643    
644    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
645    
646    15. Fixed an occurrence of == in configure.ac that should have been = (shell
647        scripts are not C programs :-) and which was not noticed because it works
648        on Linux.
649    
650    16. pcretest is supposed to handle any length of pattern and data line (as one
651        line or as a continued sequence of lines) by extending its input buffer if
652        necessary. This feature was broken for very long pattern lines, leading to
653        a string of junk being passed to pcre_compile() if the pattern was longer
654        than about 50K.
655    
656    17. I have done a major re-factoring of the way pcre_compile() computes the
657        amount of memory needed for a compiled pattern. Previously, there was code
658        that made a preliminary scan of the pattern in order to do this. That was
659        OK when PCRE was new, but as the facilities have expanded, it has become
660        harder and harder to keep it in step with the real compile phase, and there
661        have been a number of bugs (see for example, 4 above). I have now found a
662        cunning way of running the real compile function in a "fake" mode that
663        enables it to compute how much memory it would need, while actually only
664        ever using a few hundred bytes of working memory and without too many
665        tests of the mode. This should make future maintenance and development
666        easier. A side effect of this work is that the limit of 200 on the nesting
667        depth of parentheses has been removed (though this was never a serious
668        limitation, I suspect). However, there is a downside: pcre_compile() now
669        runs more slowly than before (30% or more, depending on the pattern). I
670        hope this isn't a big issue. There is no effect on runtime performance.
671    
672    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
673        newline (only possible for the last line of a file) and it was a
674        pattern that set a locale (followed by /Lsomething), pcretest crashed.
675    
676    19. Added additional timing features to pcretest. (1) The -tm option now times
677        matching only, not compiling. (2) Both -t and -tm can be followed, as a
678        separate command line item, by a number that specifies the number of
679        repeats to use when timing. The default is 50000; this gives better
680        precision, but takes uncomfortably long for very large patterns.
681    
682    20. Extended pcre_study() to be more clever in cases where a branch of a
683        subpattern has no definite first character. For example, (a*|b*)[cd] would
684        previously give no result from pcre_study(). Now it recognizes that the
685        first character must be a, b, c, or d.
686    
687    21. There was an incorrect error "recursive call could loop indefinitely" if
688        a subpattern (or the entire pattern) that was being tested for matching an
689        empty string contained only one non-empty item after a nested subpattern.
690        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
691        incorrectly, because the \d was being skipped in the check.
692    
693    22. The pcretest program now has a new pattern option /B and a command line
694        option -b, which is equivalent to adding /B to every pattern. This causes
695        it to show the compiled bytecode, without the additional information that
696        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
697        is the same as /B/I).
698    
699    23. A new optimization is now able automatically to treat some sequences such
700        as a*b as a*+b. More specifically, if something simple (such as a character
701        or a simple class like \d) has an unlimited quantifier, and is followed by
702        something that cannot possibly match the quantified thing, the quantifier
703        is automatically "possessified".
704    
705    24. A recursive reference to a subpattern whose number was greater than 39
706        went wrong under certain circumstances in UTF-8 mode. This bug could also
707        have affected the operation of pcre_study().
708    
709    25. Realized that a little bit of performance could be had by replacing
710        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
711    
712    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
713    
714    27. Possessive quantifiers such as a++ were previously implemented by turning
715        them into atomic groups such as ($>a+). Now they have their own opcodes,
716        which improves performance. This includes the automatically created ones
717        from 23 above.
718    
719    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
720        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
721        the first matched character to be a colon. This applied both to named and
722        numbered groups.
723    
724    29. The ucpinternal.h header file was missing its idempotency #ifdef.
725    
726    30. I was sent a "project" file called libpcre.a.dev which I understand makes
727        building PCRE on Windows easier, so I have included it in the distribution.
728    
729    31. There is now a check in pcretest against a ridiculously large number being
730        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
731        loop, the loop is abandoned.
732    
733    32. Forward references to subpatterns in conditions such as (?(2)...) where
734        subpattern 2 is defined later cause pcre_compile() to search forwards in
735        the pattern for the relevant set of parentheses. This search went wrong
736        when there were unescaped parentheses in a character class, parentheses
737        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
738    
739    33. "Subroutine" calls and backreferences were previously restricted to
740        referencing subpatterns earlier in the regex. This restriction has now
741        been removed.
742    
743    34. Added a number of extra features that are going to be in Perl 5.10. On the
744        whole, these are just syntactic alternatives for features that PCRE had
745        previously implemented using the Python syntax or my own invention. The
746        other formats are all retained for compatibility.
747    
748        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
749            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
750            also .NET compatible.
751    
752        (b) A recursion or subroutine call to a named group can now be defined as
753            (?&name) as well as (?P>name).
754    
755        (c) A backreference to a named group can now be defined as \k<name> or
756            \k'name' as well as (?P=name). The new forms, as well as being in Perl
757            5.10, are also .NET compatible.
758    
759        (d) A conditional reference to a named group can now use the syntax
760            (?(<name>) or (?('name') as well as (?(name).
761    
762        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
763            groups (named and numbered) that are never evaluated inline, but can be
764            called as "subroutines" from elsewhere. In effect, the DEFINE condition
765            is always false. There may be only one alternative in such a group.
766    
767        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
768            as the simple (?(R). The condition is true only if the most recent
769            recursion is that of the given number or name. It does not search out
770            through the entire recursion stack.
771    
772        (g) The escape \gN or \g{N} has been added, where N is a positive or
773            negative number, specifying an absolute or relative reference.
774    
775    35. Tidied to get rid of some further signed/unsigned compiler warnings and
776        some "unreachable code" warnings.
777    
778    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
779        things, this adds five new scripts.
780    
781    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
782        There were also incompatibilities regarding the handling of \Q..\E inside
783        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
784        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
785    
786    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
787        matches an empty string, and forcibly breaks the loop. There were bugs in
788        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
789        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
790        separate and independent bugs (that affected different cases) have been
791        fixed.
792    
793    39. Refactored the code to abolish the use of different opcodes for small
794        capturing bracket numbers. This is a tidy that I avoided doing when I
795        removed the limit on the number of capturing brackets for 3.5 back in 2001.
796        The new approach is not only tidier, it makes it possible to reduce the
797        memory needed to fix the previous bug (38).
798    
799    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
800        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
801        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
802        mode.
803    
804    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
805        report.
806    
807    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
808        copy construction and assignment in the C++ wrapper.
809    
810    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
811        couple of bugs that could have given wrong results in the "--newline=crlf"
812        case.
813    
814    44. Added a number of casts and did some reorganization of signed/unsigned int
815        variables following suggestions from Dair Grant. Also renamed the variable
816        "this" as "item" because it is a C++ keyword.
817    
818    45. Arranged for dftables to add
819    
820          #include "pcre_internal.h"
821    
822        to pcre_chartables.c because without it, gcc 4.x may remove the array
823        definition from the final binary if PCRE is built into a static library and
824        dead code stripping is activated.
825    
826    46. For an unanchored pattern, if a match attempt fails at the start of a
827        newline sequence, and the newline setting is CRLF or ANY, and the next two
828        characters are CRLF, advance by two characters instead of one.
829    
830    
831    Version 6.7 04-Jul-06
832    ---------------------
833    
834     1. In order to handle tests when input lines are enormously long, pcretest has
835        been re-factored so that it automatically extends its buffers when
836        necessary. The code is crude, but this _is_ just a test program. The
837        default size has been increased from 32K to 50K.
838    
839     2. The code in pcre_study() was using the value of the re argument before
840        testing it for NULL. (Of course, in any sensible call of the function, it
841        won't be NULL.)
842    
843     3. The memmove() emulation function in pcre_internal.h, which is used on
844        systems that lack both memmove() and bcopy() - that is, hardly ever -
845        was missing a "static" storage class specifier.
846    
847     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
848        containing an extended class (one that cannot be represented by a bitmap
849        because it contains high-valued characters or Unicode property items, e.g.
850        [\pZ]). Almost always one would set UTF-8 mode when processing such a
851        pattern, but PCRE should not loop if you do not (it no longer does).
852        [Detail: two cases were found: (a) a repeated subpattern containing an
853        extended class; (b) a recursive reference to a subpattern that followed a
854        previous extended class. It wasn't skipping over the extended class
855        correctly when UTF-8 mode was not set.]
856    
857     5. A negated single-character class was not being recognized as fixed-length
858        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
859        compile error "lookbehind assertion is not fixed length".
860    
861     6. The RunPerlTest auxiliary script was showing an unexpected difference
862        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
863        write a Perl script that can interpret lines of an input file either as
864        byte characters or as UTF-8, which is what "perltest" was being required to
865        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
866        can't do is switch easily at run time between having the "use utf8;" pragma
867        or not. In the end, I fudged it by using the RunPerlTest script to insert
868        "use utf8;" explicitly for the UTF-8 tests.
869    
870     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
871        the end of the subject string, contrary to the documentation and to what
872        Perl does. This was true of both matching functions. Now it matches only at
873        the start of the subject and immediately after *internal* newlines.
874    
875     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
876        a pointer to an int instead of a pointer to an unsigned long int. This
877        caused problems on 64-bit systems.
878    
879     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
880        instance of the 'standard' template library not being so standard".
881    
882    10. There was no check on the number of named subpatterns nor the maximum
883        length of a subpattern name. The product of these values is used to compute
884        the size of the memory block for a compiled pattern. By supplying a very
885        long subpattern name and a large number of named subpatterns, the size
886        computation could be caused to overflow. This is now prevented by limiting
887        the length of names to 32 characters, and the number of named subpatterns
888        to 10,000.
889    
890    11. Subpatterns that are repeated with specific counts have to be replicated in
891        the compiled pattern. The size of memory for this was computed from the
892        length of the subpattern and the repeat count. The latter is limited to
893        65535, but there was no limit on the former, meaning that integer overflow
894        could in principle occur. The compiled length of a repeated subpattern is
895        now limited to 30,000 bytes in order to prevent this.
896    
897    12. Added the optional facility to have named substrings with the same name.
898    
899    13. Added the ability to use a named substring as a condition, using the
900        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
901        are numbers (not recommended). Forward references are permitted.
902    
903    14. Added forward references in named backreferences (if you see what I mean).
904    
905    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
906        pattern could run off the end of the subject. For example, the pattern
907        "(?s)(.{1,5})"8 did this with the subject "ab".
908    
909    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
910        PCRE_CASELESS was set when matching characters that were quantified with ?
911        or *.
912    
913    17. A character class other than a single negated character that had a minimum
914        but no maximum quantifier - for example [ab]{6,} - was not handled
915        correctly by pce_dfa_exec(). It would match only one character.
916    
917    18. A valid (though odd) pattern that looked like a POSIX character
918        class but used an invalid character after [ (for example [[,abc,]]) caused
919        pcre_compile() to give the error "Failed: internal error: code overflow" or
920        in some cases to crash with a glibc free() error. This could even happen if
921        the pattern terminated after [[ but there just happened to be a sequence of
922        letters, a binary zero, and a closing ] in the memory that followed.
923    
924    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
925        over the years. Originally (before any Unicode support), just the bottom 8
926        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
927        output from "man perlunicode" includes this:
928    
929          The regular expression compiler produces polymorphic opcodes.  That
930          is, the pattern adapts to the data and automatically switches to
931          the Unicode character scheme when presented with Unicode data--or
932          instead uses a traditional byte scheme when presented with byte
933          data.
934    
935        Sadly, a wide octal escape does not cause a switch, and in a string with
936        no other multibyte characters, these octal escapes are treated as before.
937        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
938        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
939        Unicode string.
940    
941        I have not perpetrated such confusion in PCRE. Up till now, it took just
942        the bottom 8 bits, as in old Perl. I have now made octal escapes with
943        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
944        translate to the appropriate multibyte character.
945    
946    29. Applied some refactoring to reduce the number of warnings from Microsoft
947        and Borland compilers. This has included removing the fudge introduced
948        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
949        a warning about an unused variable.
950    
951    21. PCRE has not included VT (character 0x0b) in the set of whitespace
952        characters since release 4.0, because Perl (from release 5.004) does not.
953        [Or at least, is documented not to: some releases seem to be in conflict
954        with the documentation.] However, when a pattern was studied with
955        pcre_study() and all its branches started with \s, PCRE still included VT
956        as a possible starting character. Of course, this did no harm; it just
957        caused an unnecessary match attempt.
958    
959    22. Removed a now-redundant internal flag bit that recorded the fact that case
960        dependency changed within the pattern. This was once needed for "required
961        byte" processing, but is no longer used. This recovers a now-scarce options
962        bit. Also moved the least significant internal flag bit to the most-
963        significant bit of the word, which was not previously used (hangover from
964        the days when it was an int rather than a uint) to free up another bit for
965        the future.
966    
967    23. Added support for CRLF line endings as well as CR and LF. As well as the
968        default being selectable at build time, it can now be changed at runtime
969        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
970        specify that it is scanning data with non-default line endings.
971    
972    24. Changed the definition of CXXLINK to make it agree with the definition of
973        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
974    
975    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
976        recursions. This makes a big different to stack usage for some patterns.
977    
978    26. If a subpattern containing a named recursion or subroutine reference such
979        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
980        the space required for the compiled pattern went wrong and gave too small a
981        value. Depending on the environment, this could lead to "Failed: internal
982        error: code overflow at offset 49" or "glibc detected double free or
983        corruption" errors.
984    
985    27. Applied patches from Google (a) to support the new newline modes and (b) to
986        advance over multibyte UTF-8 characters in GlobalReplace.
987    
988    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
989        difference for some implementation of PCRE in some Windows version.
990    
991    29. Added some extra testing facilities to pcretest:
992    
993        \q<number>   in a data line sets the "match limit" value
994        \Q<number>   in a data line sets the "match recursion limt" value
995        -S <number>  sets the stack size, where <number> is in megabytes
996    
997        The -S option isn't available for Windows.
998    
999    
1000    Version 6.6 06-Feb-06
1001    ---------------------
1002    
1003     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1004        in pcreposix.h. I have copied the definition from pcre.h.
1005    
1006     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1007        because pcre.h is no longer a built file.
1008    
1009     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1010        not normally included in the compiled code.
1011    
1012    
1013  Version 6.5 01-Feb-06  Version 6.5 01-Feb-06
1014  ---------------------  ---------------------
1015    

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