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

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