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

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