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revision 89 by nigel, Sat Feb 24 21:41:27 2007 UTC revision 287 by ph10, Tue Dec 18 20:11:28 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    17. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
95    
96    18. Added --enable-pcretest-libreadline.
97    
98    
99    Version 7.4 21-Sep-07
100    ---------------------
101    
102    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
103        means that a class such as [\s] counted as "explicit reference to CR or
104        LF". That isn't really right - the whole point of the change was to try to
105        help when there was an actual mention of one of the two characters. So now
106        the change happens only if \r or \n (or a literal CR or LF) character is
107        encountered.
108    
109    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
110        of both had grown to the point where there were only 3 bits left.
111        Fortunately, there was spare space in the data structure, and so I have
112        moved the internal flags into a new 16-bit field to free up more option
113        bits.
114    
115    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
116        but did not set the internal JCHANGED flag - either of these is enough to
117        control the way the "get" function works - but the PCRE_INFO_JCHANGED
118        facility is supposed to tell if (?J) was ever used, so now (?J) at the
119        start sets both bits.
120    
121    4.  Added options (at build time, compile time, exec time) to change \R from
122        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
123    
124    5.  doc/pcresyntax.html was missing from the distribution.
125    
126    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
127        compatibility, even though it is no longer used.
128    
129    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
130        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
131        windows.h file is present (where different names are used). [This was
132        reversed later after testing - see 16 below.]
133    
134    8.  Changed all #include <config.h> to #include "config.h". There were also
135        some further <pcre.h> cases that I changed to "pcre.h".
136    
137    9.  When pcregrep was used with the --colour option, it missed the line ending
138        sequence off the lines that it output.
139    
140    10. It was pointed out to me that arrays of string pointers cause lots of
141        relocations when a shared library is dynamically loaded. A technique of
142        using a single long string with a table of offsets can drastically reduce
143        these. I have refactored PCRE in four places to do this. The result is
144        dramatic:
145    
146          Originally:                          290
147          After changing UCP table:            187
148          After changing error message table:   43
149          After changing table of "verbs"       36
150          After changing table of Posix names   22
151    
152        Thanks to the folks working on Gregex for glib for this insight.
153    
154    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
155        unicode-properties was also set.
156    
157    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
158    
159    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
160        checked only for CRLF.
161    
162    14. Added casts to pcretest.c to avoid compiler warnings.
163    
164    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
165    
166    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
167        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
168        entirely. This removes changes made in 7 above.
169    
170    17. The CMake files have been updated, and there is now more information about
171        building with CMake in the NON-UNIX-USE document.
172    
173    
174    Version 7.3 28-Aug-07
175    ---------------------
176    
177     1. In the rejigging of the build system that eventually resulted in 7.1, the
178        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
179        brackets there is not right, since it causes compilers to look for an
180        installed pcre.h, not the version that is in the source that is being
181        compiled (which of course may be different). I have changed it back to:
182    
183          #include "pcre.h"
184    
185        I have a vague recollection that the change was concerned with compiling in
186        different directories, but in the new build system, that is taken care of
187        by the VPATH setting the Makefile.
188    
189     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
190        when the subject happened to end in the byte 0x85 (e.g. if the last
191        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
192        characters but of course it shouldn't be taken as a newline when it is part
193        of another character. The bug was that, for an unlimited repeat of . in
194        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
195        characters when looking for a newline.
196    
197     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
198    
199     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
200        in debug output.
201    
202     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
203        long printing in the pcrecpp unittest when running under MinGW.
204    
205     6. ESC_K was left out of the EBCDIC table.
206    
207     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
208        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
209        limit also applies to "virtual nesting" when a pattern is recursive, and in
210        this case 1000 isn't so big. I have been able to remove this limit at the
211        expense of backing off one optimization in certain circumstances. Normally,
212        when pcre_exec() would call its internal match() function recursively and
213        immediately return the result unconditionally, it uses a "tail recursion"
214        feature to save stack. However, when a subpattern that can match an empty
215        string has an unlimited repetition quantifier, it no longer makes this
216        optimization. That gives it a stack frame in which to save the data for
217        checking that an empty string has been matched. Previously this was taken
218        from the 1000-entry workspace that had been reserved. So now there is no
219        explicit limit, but more stack is used.
220    
221     8. Applied Daniel's patches to solve problems with the import/export magic
222        syntax that is required for Windows, and which was going wrong for the
223        pcreposix and pcrecpp parts of the library. These were overlooked when this
224        problem was solved for the main library.
225    
226     9. There were some crude static tests to avoid integer overflow when computing
227        the size of patterns that contain repeated groups with explicit upper
228        limits. As the maximum quantifier is 65535, the maximum group length was
229        set at 30,000 so that the product of these two numbers did not overflow a
230        32-bit integer. However, it turns out that people want to use groups that
231        are longer than 30,000 bytes (though not repeat them that many times).
232        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
233        made it possible to implement the integer overflow checks in a much more
234        dynamic way, which I have now done. The artificial limitation on group
235        length has been removed - we now have only the limit on the total length of
236        the compiled pattern, which depends on the LINK_SIZE setting.
237    
238    10. Fixed a bug in the documentation for get/copy named substring when
239        duplicate names are permitted. If none of the named substrings are set, the
240        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
241        empty string.
242    
243    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
244        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
245        because the ] is interpreted as the first data character and the
246        terminating ] is not found. PCRE has been made compatible with Perl in this
247        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
248        cause memory overwriting.
249    
250    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
251        string has been matched (to stop an infinite loop). It was not recognizing
252        a conditional subpattern that could match an empty string if that
253        subpattern was within another subpattern. For example, it looped when
254        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
255        condition was not nested. This bug has been fixed.
256    
257    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
258        past the start of the subject in the presence of bytes with the top bit
259        set, for example "\x8aBCD".
260    
261    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
262        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
263    
264    14. Optimized (?!) to (*FAIL).
265    
266    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
267        This restricts code points to be within the range 0 to 0x10FFFF, excluding
268        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
269        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
270        does: it's just the validity check that is more restrictive.
271    
272    16. Inserted checks for integer overflows during escape sequence (backslash)
273        processing, and also fixed erroneous offset values for syntax errors during
274        backslash processing.
275    
276    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
277        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
278    
279    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
280        caused an overrun.
281    
282    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
283        something other than just ASCII characters) inside a group that had an
284        unlimited repeat caused a loop at compile time (while checking to see
285        whether the group could match an empty string).
286    
287    20. Debugging a pattern containing \p or \P could cause a crash. For example,
288        [\P{Any}] did so. (Error in the code for printing property names.)
289    
290    21. An orphan \E inside a character class could cause a crash.
291    
292    22. A repeated capturing bracket such as (A)? could cause a wild memory
293        reference during compilation.
294    
295    23. There are several functions in pcre_compile() that scan along a compiled
296        expression for various reasons (e.g. to see if it's fixed length for look
297        behind). There were bugs in these functions when a repeated \p or \P was
298        present in the pattern. These operators have additional parameters compared
299        with \d, etc, and these were not being taken into account when moving along
300        the compiled data. Specifically:
301    
302        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
303            length.
304    
305        (b) An item such as \pL+ within a repeated group could cause crashes or
306            loops.
307    
308        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
309            "reference to non-existent subpattern" error.
310    
311        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
312    
313    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
314        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
315    
316    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
317    
318    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
319        character were causing crashes (broken optimization).
320    
321    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
322        \p or \P) caused a compile-time loop.
323    
324    28. More problems have arisen in unanchored patterns when CRLF is a valid line
325        break. For example, the unstudied pattern [\r\n]A does not match the string
326        "\r\nA" because change 7.0/46 below moves the current point on by two
327        characters after failing to match at the start. However, the pattern \nA
328        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
329        the same is true. There doesn't seem any very clean way out of this, but
330        what I have chosen to do makes the common cases work: PCRE now takes note
331        of whether there can be an explicit match for \r or \n anywhere in the
332        pattern, and if so, 7.0/46 no longer applies. As part of this change,
333        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
334        pattern has explicit CR or LF references.
335    
336    29. Added (*CR) etc for changing newline setting at start of pattern.
337    
338    
339    Version 7.2 19-Jun-07
340    ---------------------
341    
342     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
343        which is apparently normally available under Windows.
344    
345     2. Re-jig the pcregrep tests with different newline settings in an attempt
346        to make them independent of the local environment's newline setting.
347    
348     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
349    
350     4. Some of the "internals" tests were previously cut out when the link size
351        was not 2, because the output contained actual offsets. The recent new
352        "Z" feature of pcretest means that these can be cut out, making the tests
353        usable with all link sizes.
354    
355     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
356        stack recursion. This gives a massive performance boost under BSD, but just
357        a small improvement under Linux. However, it saves one field in the frame
358        in all cases.
359    
360     6. Added more features from the forthcoming Perl 5.10:
361    
362        (a) (?-n) (where n is a string of digits) is a relative subroutine or
363            recursion call. It refers to the nth most recently opened parentheses.
364    
365        (b) (?+n) is also a relative subroutine call; it refers to the nth next
366            to be opened parentheses.
367    
368        (c) Conditions that refer to capturing parentheses can be specified
369            relatively, for example, (?(-2)... or (?(+3)...
370    
371        (d) \K resets the start of the current match so that everything before
372            is not part of it.
373    
374        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
375    
376        (f) \g{name} is another synonym - part of Perl 5.10's unification of
377            reference syntax.
378    
379        (g) (?| introduces a group in which the numbering of parentheses in each
380            alternative starts with the same number.
381    
382        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
383    
384     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
385        PCRE_INFO_JCHANGED.
386    
387     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
388        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
389        for detecting groups that can match an empty string.
390    
391     9. A pattern with a very large number of alternatives (more than several
392        hundred) was running out of internal workspace during the pre-compile
393        phase, where pcre_compile() figures out how much memory will be needed. A
394        bit of new cunning has reduced the workspace needed for groups with
395        alternatives. The 1000-alternative test pattern now uses 12 bytes of
396        workspace instead of running out of the 4096 that are available.
397    
398    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
399    
400    11. Applied patch from Google to remove an optimization that didn't quite work.
401        The report of the bug said:
402    
403          pcrecpp::RE("a*").FullMatch("aaa") matches, while
404          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
405          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
406    
407    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
408        it matched the wrong number of bytes.
409    
410    
411    Version 7.1 24-Apr-07
412    ---------------------
413    
414     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
415        that is more "standard", making use of automake and other Autotools. There
416        is some re-arrangement of the files and adjustment of comments consequent
417        on this.
418    
419     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
420        for recursive directory scanning broke on some systems because the files
421        are not scanned in any specific order and on different systems the order
422        was different. A call to "sort" has been inserted into RunGrepTest for the
423        approprate test as a short-term fix. In the longer term there may be an
424        alternative.
425    
426     3. I had an email from Eric Raymond about problems translating some of PCRE's
427        man pages to HTML (despite the fact that I distribute HTML pages, some
428        people do their own conversions for various reasons). The problems
429        concerned the use of low-level troff macros .br and .in. I have therefore
430        removed all such uses from the man pages (some were redundant, some could
431        be replaced by .nf/.fi pairs). The 132html script that I use to generate
432        HTML has been updated to handle .nf/.fi and to complain if it encounters
433        .br or .in.
434    
435     4. Updated comments in configure.ac that get placed in config.h.in and also
436        arranged for config.h to be included in the distribution, with the name
437        config.h.generic, for the benefit of those who have to compile without
438        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
439    
440     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
441        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
442        makevp.bat for the current PCRE, using the additional files
443        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
444    
445     6. A Windows user reported a minor discrepancy with test 2, which turned out
446        to be caused by a trailing space on an input line that had got lost in his
447        copy. The trailing space was an accident, so I've just removed it.
448    
449     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
450        that is needed.
451    
452     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
453        as "const" (a) because they are and (b) because it helps the PHP
454        maintainers who have recently made a script to detect big data structures
455        in the php code that should be moved to the .rodata section. I remembered
456        to update Builducptable as well, so it won't revert if ucptable.h is ever
457        re-created.
458    
459     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
460        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
461        order to be able to cut out the UTF-8 tables in the latter when UTF-8
462        support is not required. This saves 1.5-2K of code, which is important in
463        some applications.
464    
465        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
466        so as not to refer to the tables, even though these functions will never be
467        called when UTF-8 support is disabled. Otherwise there are problems with a
468        shared library.
469    
470    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
471    
472        (a) It was defining its arguments as char * instead of void *.
473    
474        (b) It was assuming that all moves were upwards in memory; this was true
475            a long time ago when I wrote it, but is no longer the case.
476    
477        The emulated memove() is provided for those environments that have neither
478        memmove() nor bcopy(). I didn't think anyone used it these days, but that
479        is clearly not the case, as these two bugs were recently reported.
480    
481    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
482        and Detrail to create the HTML documentation, the .txt form of the man
483        pages, and it removes trailing spaces from listed files. It also creates
484        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
485        case, it wraps all the #defines with #ifndefs. This script should be run
486        before "make dist".
487    
488    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
489        with Unicode property support.
490    
491        (a) For a maximizing quantifier, if the two different cases of the
492            character were of different lengths in their UTF-8 codings (there are
493            some cases like this - I found 11), and the matching function had to
494            back up over a mixture of the two cases, it incorrectly assumed they
495            were both the same length.
496    
497        (b) When PCRE was configured to use the heap rather than the stack for
498            recursion during matching, it was not correctly preserving the data for
499            the other case of a UTF-8 character when checking ahead for a match
500            while processing a minimizing repeat. If the check also involved
501            matching a wide character, but failed, corruption could cause an
502            erroneous result when trying to check for a repeat of the original
503            character.
504    
505    13. Some tidying changes to the testing mechanism:
506    
507        (a) The RunTest script now detects the internal link size and whether there
508            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
509            values substituted by "configure". (The RunGrepTest script already did
510            this for UTF-8.) The configure.ac script no longer substitutes the
511            relevant variables.
512    
513        (b) The debugging options /B and /D in pcretest show the compiled bytecode
514            with length and offset values. This means that the output is different
515            for different internal link sizes. Test 2 is skipped for link sizes
516            other than 2 because of this, bypassing the problem. Unfortunately,
517            there was also a test in test 3 (the locale tests) that used /B and
518            failed for link sizes other than 2. Rather than cut the whole test out,
519            I have added a new /Z option to pcretest that replaces the length and
520            offset values with spaces. This is now used to make test 3 independent
521            of link size. (Test 2 will be tidied up later.)
522    
523    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
524        segmentation fault instead of returning the appropriate error message.
525    
526    15. In multiline mode when the newline sequence was set to "any", the pattern
527        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
528        This doesn't seem right; it now treats the CRLF combination as the line
529        ending, and so does not match in that case. It's only a pattern such as ^$
530        that would hit this one: something like ^ABC$ would have failed after \r
531        and then tried again after \r\n.
532    
533    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
534        in an attempt to make files that differ only in their line terminators
535        compare equal. This works on Linux.
536    
537    17. Under certain error circumstances pcregrep might try to free random memory
538        as it exited. This is now fixed, thanks to valgrind.
539    
540    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
541        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
542        was because its rules for how to advance for /g after matching an empty
543        string at the end of a line did not allow for this case. They now check for
544        it specially.
545    
546    20. pcretest is supposed to handle patterns and data of any length, by
547        extending its buffers when necessary. It was getting this wrong when the
548        buffer for a data line had to be extended.
549    
550    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
551        CRLF as a newline sequence.
552    
553    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
554        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
555        I have nevertheless tidied it up.
556    
557    23. Added some casts to kill warnings from HP-UX ia64 compiler.
558    
559    24. Added a man page for pcre-config.
560    
561    
562    Version 7.0 19-Dec-06
563    ---------------------
564    
565     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
566        moving to gcc 4.1.1.
567    
568     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
569        sys/time.h, which is documented as needed for this function. It doesn't
570        seem to matter on Linux, but it showed up on some releases of OS X.
571    
572     3. It seems that there are systems where bytes whose values are greater than
573        127 match isprint() in the "C" locale. The "C" locale should be the
574        default when a C program starts up. In most systems, only ASCII printing
575        characters match isprint(). This difference caused the output from pcretest
576        to vary, making some of the tests fail. I have changed pcretest so that:
577    
578        (a) When it is outputting text in the compiled version of a pattern, bytes
579            other than 32-126 are always shown as hex escapes.
580    
581        (b) When it is outputting text that is a matched part of a subject string,
582            it does the same, unless a different locale has been set for the match
583            (using the /L modifier). In this case, it uses isprint() to decide.
584    
585     4. Fixed a major bug that caused incorrect computation of the amount of memory
586        required for a compiled pattern when options that changed within the
587        pattern affected the logic of the preliminary scan that determines the
588        length. The relevant options are -x, and -i in UTF-8 mode. The result was
589        that the computed length was too small. The symptoms of this bug were
590        either the PCRE error "internal error: code overflow" from pcre_compile(),
591        or a glibc crash with a message such as "pcretest: free(): invalid next
592        size (fast)". Examples of patterns that provoked this bug (shown in
593        pcretest format) are:
594    
595          /(?-x: )/x
596          /(?x)(?-x: \s*#\s*)/
597          /((?i)[\x{c0}])/8
598          /(?i:[\x{c0}])/8
599    
600        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
601        is now done differently.
602    
603     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
604        wrapper classes; (b) implement a new function in the C++ scanner that is
605        more efficient than the old way of doing things because it avoids levels of
606        recursion in the regex matching; (c) add a paragraph to the documentation
607        for the FullMatch() function.
608    
609     6. The escape sequence \n was being treated as whatever was defined as
610        "newline". Not only was this contrary to the documentation, which states
611        that \n is character 10 (hex 0A), but it also went horribly wrong when
612        "newline" was defined as CRLF. This has been fixed.
613    
614     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
615        was being set to -1 for the "end of line" case (supposedly a value that no
616        character can have). Though this value is never used (the check for end of
617        line is "zero bytes in current character"), it caused compiler complaints.
618        I've changed it to 0xffffffff.
619    
620     8. In pcre_version.c, the version string was being built by a sequence of
621        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
622        string (as it is for production releases) called a macro with an empty
623        argument. The C standard says the result of this is undefined. The gcc
624        compiler treats it as an empty string (which was what was wanted) but it is
625        reported that Visual C gives an error. The source has been hacked around to
626        avoid this problem.
627    
628     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
629        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
630        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
631        of them did).
632    
633    10. Originally, pcretest opened its input and output without "b"; then I was
634        told that "b" was needed in some environments, so it was added for release
635        5.0 to both the input and output. (It makes no difference on Unix-like
636        systems.) Later I was told that it is wrong for the input on Windows. I've
637        now abstracted the modes into two macros, to make it easier to fiddle with
638        them, and removed "b" from the input mode under Windows.
639    
640    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
641    
642    12. Added -help and --help to pcretest as an official way of being reminded
643        of the options.
644    
645    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
646        and pcrecpp.cc because they annoy compilers at high warning levels.
647    
648    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
649    
650    15. Fixed an occurrence of == in configure.ac that should have been = (shell
651        scripts are not C programs :-) and which was not noticed because it works
652        on Linux.
653    
654    16. pcretest is supposed to handle any length of pattern and data line (as one
655        line or as a continued sequence of lines) by extending its input buffer if
656        necessary. This feature was broken for very long pattern lines, leading to
657        a string of junk being passed to pcre_compile() if the pattern was longer
658        than about 50K.
659    
660    17. I have done a major re-factoring of the way pcre_compile() computes the
661        amount of memory needed for a compiled pattern. Previously, there was code
662        that made a preliminary scan of the pattern in order to do this. That was
663        OK when PCRE was new, but as the facilities have expanded, it has become
664        harder and harder to keep it in step with the real compile phase, and there
665        have been a number of bugs (see for example, 4 above). I have now found a
666        cunning way of running the real compile function in a "fake" mode that
667        enables it to compute how much memory it would need, while actually only
668        ever using a few hundred bytes of working memory and without too many
669        tests of the mode. This should make future maintenance and development
670        easier. A side effect of this work is that the limit of 200 on the nesting
671        depth of parentheses has been removed (though this was never a serious
672        limitation, I suspect). However, there is a downside: pcre_compile() now
673        runs more slowly than before (30% or more, depending on the pattern). I
674        hope this isn't a big issue. There is no effect on runtime performance.
675    
676    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
677        newline (only possible for the last line of a file) and it was a
678        pattern that set a locale (followed by /Lsomething), pcretest crashed.
679    
680    19. Added additional timing features to pcretest. (1) The -tm option now times
681        matching only, not compiling. (2) Both -t and -tm can be followed, as a
682        separate command line item, by a number that specifies the number of
683        repeats to use when timing. The default is 50000; this gives better
684        precision, but takes uncomfortably long for very large patterns.
685    
686    20. Extended pcre_study() to be more clever in cases where a branch of a
687        subpattern has no definite first character. For example, (a*|b*)[cd] would
688        previously give no result from pcre_study(). Now it recognizes that the
689        first character must be a, b, c, or d.
690    
691    21. There was an incorrect error "recursive call could loop indefinitely" if
692        a subpattern (or the entire pattern) that was being tested for matching an
693        empty string contained only one non-empty item after a nested subpattern.
694        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
695        incorrectly, because the \d was being skipped in the check.
696    
697    22. The pcretest program now has a new pattern option /B and a command line
698        option -b, which is equivalent to adding /B to every pattern. This causes
699        it to show the compiled bytecode, without the additional information that
700        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
701        is the same as /B/I).
702    
703    23. A new optimization is now able automatically to treat some sequences such
704        as a*b as a*+b. More specifically, if something simple (such as a character
705        or a simple class like \d) has an unlimited quantifier, and is followed by
706        something that cannot possibly match the quantified thing, the quantifier
707        is automatically "possessified".
708    
709    24. A recursive reference to a subpattern whose number was greater than 39
710        went wrong under certain circumstances in UTF-8 mode. This bug could also
711        have affected the operation of pcre_study().
712    
713    25. Realized that a little bit of performance could be had by replacing
714        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
715    
716    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
717    
718    27. Possessive quantifiers such as a++ were previously implemented by turning
719        them into atomic groups such as ($>a+). Now they have their own opcodes,
720        which improves performance. This includes the automatically created ones
721        from 23 above.
722    
723    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
724        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
725        the first matched character to be a colon. This applied both to named and
726        numbered groups.
727    
728    29. The ucpinternal.h header file was missing its idempotency #ifdef.
729    
730    30. I was sent a "project" file called libpcre.a.dev which I understand makes
731        building PCRE on Windows easier, so I have included it in the distribution.
732    
733    31. There is now a check in pcretest against a ridiculously large number being
734        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
735        loop, the loop is abandoned.
736    
737    32. Forward references to subpatterns in conditions such as (?(2)...) where
738        subpattern 2 is defined later cause pcre_compile() to search forwards in
739        the pattern for the relevant set of parentheses. This search went wrong
740        when there were unescaped parentheses in a character class, parentheses
741        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
742    
743    33. "Subroutine" calls and backreferences were previously restricted to
744        referencing subpatterns earlier in the regex. This restriction has now
745        been removed.
746    
747    34. Added a number of extra features that are going to be in Perl 5.10. On the
748        whole, these are just syntactic alternatives for features that PCRE had
749        previously implemented using the Python syntax or my own invention. The
750        other formats are all retained for compatibility.
751    
752        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
753            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
754            also .NET compatible.
755    
756        (b) A recursion or subroutine call to a named group can now be defined as
757            (?&name) as well as (?P>name).
758    
759        (c) A backreference to a named group can now be defined as \k<name> or
760            \k'name' as well as (?P=name). The new forms, as well as being in Perl
761            5.10, are also .NET compatible.
762    
763        (d) A conditional reference to a named group can now use the syntax
764            (?(<name>) or (?('name') as well as (?(name).
765    
766        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
767            groups (named and numbered) that are never evaluated inline, but can be
768            called as "subroutines" from elsewhere. In effect, the DEFINE condition
769            is always false. There may be only one alternative in such a group.
770    
771        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
772            as the simple (?(R). The condition is true only if the most recent
773            recursion is that of the given number or name. It does not search out
774            through the entire recursion stack.
775    
776        (g) The escape \gN or \g{N} has been added, where N is a positive or
777            negative number, specifying an absolute or relative reference.
778    
779    35. Tidied to get rid of some further signed/unsigned compiler warnings and
780        some "unreachable code" warnings.
781    
782    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
783        things, this adds five new scripts.
784    
785    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
786        There were also incompatibilities regarding the handling of \Q..\E inside
787        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
788        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
789    
790    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
791        matches an empty string, and forcibly breaks the loop. There were bugs in
792        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
793        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
794        separate and independent bugs (that affected different cases) have been
795        fixed.
796    
797    39. Refactored the code to abolish the use of different opcodes for small
798        capturing bracket numbers. This is a tidy that I avoided doing when I
799        removed the limit on the number of capturing brackets for 3.5 back in 2001.
800        The new approach is not only tidier, it makes it possible to reduce the
801        memory needed to fix the previous bug (38).
802    
803    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
804        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
805        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
806        mode.
807    
808    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
809        report.
810    
811    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
812        copy construction and assignment in the C++ wrapper.
813    
814    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
815        couple of bugs that could have given wrong results in the "--newline=crlf"
816        case.
817    
818    44. Added a number of casts and did some reorganization of signed/unsigned int
819        variables following suggestions from Dair Grant. Also renamed the variable
820        "this" as "item" because it is a C++ keyword.
821    
822    45. Arranged for dftables to add
823    
824          #include "pcre_internal.h"
825    
826        to pcre_chartables.c because without it, gcc 4.x may remove the array
827        definition from the final binary if PCRE is built into a static library and
828        dead code stripping is activated.
829    
830    46. For an unanchored pattern, if a match attempt fails at the start of a
831        newline sequence, and the newline setting is CRLF or ANY, and the next two
832        characters are CRLF, advance by two characters instead of one.
833    
834    
835    Version 6.7 04-Jul-06
836    ---------------------
837    
838     1. In order to handle tests when input lines are enormously long, pcretest has
839        been re-factored so that it automatically extends its buffers when
840        necessary. The code is crude, but this _is_ just a test program. The
841        default size has been increased from 32K to 50K.
842    
843     2. The code in pcre_study() was using the value of the re argument before
844        testing it for NULL. (Of course, in any sensible call of the function, it
845        won't be NULL.)
846    
847     3. The memmove() emulation function in pcre_internal.h, which is used on
848        systems that lack both memmove() and bcopy() - that is, hardly ever -
849        was missing a "static" storage class specifier.
850    
851     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
852        containing an extended class (one that cannot be represented by a bitmap
853        because it contains high-valued characters or Unicode property items, e.g.
854        [\pZ]). Almost always one would set UTF-8 mode when processing such a
855        pattern, but PCRE should not loop if you do not (it no longer does).
856        [Detail: two cases were found: (a) a repeated subpattern containing an
857        extended class; (b) a recursive reference to a subpattern that followed a
858        previous extended class. It wasn't skipping over the extended class
859        correctly when UTF-8 mode was not set.]
860    
861     5. A negated single-character class was not being recognized as fixed-length
862        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
863        compile error "lookbehind assertion is not fixed length".
864    
865     6. The RunPerlTest auxiliary script was showing an unexpected difference
866        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
867        write a Perl script that can interpret lines of an input file either as
868        byte characters or as UTF-8, which is what "perltest" was being required to
869        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
870        can't do is switch easily at run time between having the "use utf8;" pragma
871        or not. In the end, I fudged it by using the RunPerlTest script to insert
872        "use utf8;" explicitly for the UTF-8 tests.
873    
874     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
875        the end of the subject string, contrary to the documentation and to what
876        Perl does. This was true of both matching functions. Now it matches only at
877        the start of the subject and immediately after *internal* newlines.
878    
879     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
880        a pointer to an int instead of a pointer to an unsigned long int. This
881        caused problems on 64-bit systems.
882    
883     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
884        instance of the 'standard' template library not being so standard".
885    
886    10. There was no check on the number of named subpatterns nor the maximum
887        length of a subpattern name. The product of these values is used to compute
888        the size of the memory block for a compiled pattern. By supplying a very
889        long subpattern name and a large number of named subpatterns, the size
890        computation could be caused to overflow. This is now prevented by limiting
891        the length of names to 32 characters, and the number of named subpatterns
892        to 10,000.
893    
894    11. Subpatterns that are repeated with specific counts have to be replicated in
895        the compiled pattern. The size of memory for this was computed from the
896        length of the subpattern and the repeat count. The latter is limited to
897        65535, but there was no limit on the former, meaning that integer overflow
898        could in principle occur. The compiled length of a repeated subpattern is
899        now limited to 30,000 bytes in order to prevent this.
900    
901    12. Added the optional facility to have named substrings with the same name.
902    
903    13. Added the ability to use a named substring as a condition, using the
904        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
905        are numbers (not recommended). Forward references are permitted.
906    
907    14. Added forward references in named backreferences (if you see what I mean).
908    
909    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
910        pattern could run off the end of the subject. For example, the pattern
911        "(?s)(.{1,5})"8 did this with the subject "ab".
912    
913    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
914        PCRE_CASELESS was set when matching characters that were quantified with ?
915        or *.
916    
917    17. A character class other than a single negated character that had a minimum
918        but no maximum quantifier - for example [ab]{6,} - was not handled
919        correctly by pce_dfa_exec(). It would match only one character.
920    
921    18. A valid (though odd) pattern that looked like a POSIX character
922        class but used an invalid character after [ (for example [[,abc,]]) caused
923        pcre_compile() to give the error "Failed: internal error: code overflow" or
924        in some cases to crash with a glibc free() error. This could even happen if
925        the pattern terminated after [[ but there just happened to be a sequence of
926        letters, a binary zero, and a closing ] in the memory that followed.
927    
928    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
929        over the years. Originally (before any Unicode support), just the bottom 8
930        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
931        output from "man perlunicode" includes this:
932    
933          The regular expression compiler produces polymorphic opcodes.  That
934          is, the pattern adapts to the data and automatically switches to
935          the Unicode character scheme when presented with Unicode data--or
936          instead uses a traditional byte scheme when presented with byte
937          data.
938    
939        Sadly, a wide octal escape does not cause a switch, and in a string with
940        no other multibyte characters, these octal escapes are treated as before.
941        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
942        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
943        Unicode string.
944    
945        I have not perpetrated such confusion in PCRE. Up till now, it took just
946        the bottom 8 bits, as in old Perl. I have now made octal escapes with
947        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
948        translate to the appropriate multibyte character.
949    
950    29. Applied some refactoring to reduce the number of warnings from Microsoft
951        and Borland compilers. This has included removing the fudge introduced
952        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
953        a warning about an unused variable.
954    
955    21. PCRE has not included VT (character 0x0b) in the set of whitespace
956        characters since release 4.0, because Perl (from release 5.004) does not.
957        [Or at least, is documented not to: some releases seem to be in conflict
958        with the documentation.] However, when a pattern was studied with
959        pcre_study() and all its branches started with \s, PCRE still included VT
960        as a possible starting character. Of course, this did no harm; it just
961        caused an unnecessary match attempt.
962    
963    22. Removed a now-redundant internal flag bit that recorded the fact that case
964        dependency changed within the pattern. This was once needed for "required
965        byte" processing, but is no longer used. This recovers a now-scarce options
966        bit. Also moved the least significant internal flag bit to the most-
967        significant bit of the word, which was not previously used (hangover from
968        the days when it was an int rather than a uint) to free up another bit for
969        the future.
970    
971    23. Added support for CRLF line endings as well as CR and LF. As well as the
972        default being selectable at build time, it can now be changed at runtime
973        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
974        specify that it is scanning data with non-default line endings.
975    
976    24. Changed the definition of CXXLINK to make it agree with the definition of
977        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
978    
979    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
980        recursions. This makes a big different to stack usage for some patterns.
981    
982    26. If a subpattern containing a named recursion or subroutine reference such
983        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
984        the space required for the compiled pattern went wrong and gave too small a
985        value. Depending on the environment, this could lead to "Failed: internal
986        error: code overflow at offset 49" or "glibc detected double free or
987        corruption" errors.
988    
989    27. Applied patches from Google (a) to support the new newline modes and (b) to
990        advance over multibyte UTF-8 characters in GlobalReplace.
991    
992    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
993        difference for some implementation of PCRE in some Windows version.
994    
995    29. Added some extra testing facilities to pcretest:
996    
997        \q<number>   in a data line sets the "match limit" value
998        \Q<number>   in a data line sets the "match recursion limt" value
999        -S <number>  sets the stack size, where <number> is in megabytes
1000    
1001        The -S option isn't available for Windows.
1002    
1003    
1004  Version 6.6 06-Feb-06  Version 6.6 06-Feb-06
1005  ---------------------  ---------------------
1006    

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