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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 286 by ph10, Mon Dec 17 14:46:11 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.5 12-Nov-07
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
54    
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
68    
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
73    
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
78    
79    14. The pattern (?=something)(?R) was not being diagnosed as a potentially
80        infinitely looping recursion. The bug was that positive lookaheads were not
81        being skipped when checking for a possible empty match (negative lookaheads
82        and both kinds of lookbehind were skipped).
83    
84    15. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
85        inclusion of <windows.h> to before rather than after the definition of
86        INVALID_FILE_ATTRIBUTES (patch from David Byron).
87    
88    16. Specifying a possessive quantifier with a specific limit for a Unicode
89        character property caused pcre_compile() to compile bad code, which led at
90        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
91        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
92        caused the error; without that there was no problem.
93    
94    17. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
95    
96    
97    Version 7.4 21-Sep-07
98    ---------------------
99    
100    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
101        means that a class such as [\s] counted as "explicit reference to CR or
102        LF". That isn't really right - the whole point of the change was to try to
103        help when there was an actual mention of one of the two characters. So now
104        the change happens only if \r or \n (or a literal CR or LF) character is
105        encountered.
106    
107    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
108        of both had grown to the point where there were only 3 bits left.
109        Fortunately, there was spare space in the data structure, and so I have
110        moved the internal flags into a new 16-bit field to free up more option
111        bits.
112    
113    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
114        but did not set the internal JCHANGED flag - either of these is enough to
115        control the way the "get" function works - but the PCRE_INFO_JCHANGED
116        facility is supposed to tell if (?J) was ever used, so now (?J) at the
117        start sets both bits.
118    
119    4.  Added options (at build time, compile time, exec time) to change \R from
120        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
121    
122    5.  doc/pcresyntax.html was missing from the distribution.
123    
124    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
125        compatibility, even though it is no longer used.
126    
127    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
128        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
129        windows.h file is present (where different names are used). [This was
130        reversed later after testing - see 16 below.]
131    
132    8.  Changed all #include <config.h> to #include "config.h". There were also
133        some further <pcre.h> cases that I changed to "pcre.h".
134    
135    9.  When pcregrep was used with the --colour option, it missed the line ending
136        sequence off the lines that it output.
137    
138    10. It was pointed out to me that arrays of string pointers cause lots of
139        relocations when a shared library is dynamically loaded. A technique of
140        using a single long string with a table of offsets can drastically reduce
141        these. I have refactored PCRE in four places to do this. The result is
142        dramatic:
143    
144          Originally:                          290
145          After changing UCP table:            187
146          After changing error message table:   43
147          After changing table of "verbs"       36
148          After changing table of Posix names   22
149    
150        Thanks to the folks working on Gregex for glib for this insight.
151    
152    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
153        unicode-properties was also set.
154    
155    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
156    
157    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
158        checked only for CRLF.
159    
160    14. Added casts to pcretest.c to avoid compiler warnings.
161    
162    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
163    
164    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
165        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
166        entirely. This removes changes made in 7 above.
167    
168    17. The CMake files have been updated, and there is now more information about
169        building with CMake in the NON-UNIX-USE document.
170    
171    
172    Version 7.3 28-Aug-07
173    ---------------------
174    
175     1. In the rejigging of the build system that eventually resulted in 7.1, the
176        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
177        brackets there is not right, since it causes compilers to look for an
178        installed pcre.h, not the version that is in the source that is being
179        compiled (which of course may be different). I have changed it back to:
180    
181          #include "pcre.h"
182    
183        I have a vague recollection that the change was concerned with compiling in
184        different directories, but in the new build system, that is taken care of
185        by the VPATH setting the Makefile.
186    
187     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
188        when the subject happened to end in the byte 0x85 (e.g. if the last
189        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
190        characters but of course it shouldn't be taken as a newline when it is part
191        of another character. The bug was that, for an unlimited repeat of . in
192        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
193        characters when looking for a newline.
194    
195     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
196    
197     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
198        in debug output.
199    
200     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
201        long printing in the pcrecpp unittest when running under MinGW.
202    
203     6. ESC_K was left out of the EBCDIC table.
204    
205     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
206        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
207        limit also applies to "virtual nesting" when a pattern is recursive, and in
208        this case 1000 isn't so big. I have been able to remove this limit at the
209        expense of backing off one optimization in certain circumstances. Normally,
210        when pcre_exec() would call its internal match() function recursively and
211        immediately return the result unconditionally, it uses a "tail recursion"
212        feature to save stack. However, when a subpattern that can match an empty
213        string has an unlimited repetition quantifier, it no longer makes this
214        optimization. That gives it a stack frame in which to save the data for
215        checking that an empty string has been matched. Previously this was taken
216        from the 1000-entry workspace that had been reserved. So now there is no
217        explicit limit, but more stack is used.
218    
219     8. Applied Daniel's patches to solve problems with the import/export magic
220        syntax that is required for Windows, and which was going wrong for the
221        pcreposix and pcrecpp parts of the library. These were overlooked when this
222        problem was solved for the main library.
223    
224     9. There were some crude static tests to avoid integer overflow when computing
225        the size of patterns that contain repeated groups with explicit upper
226        limits. As the maximum quantifier is 65535, the maximum group length was
227        set at 30,000 so that the product of these two numbers did not overflow a
228        32-bit integer. However, it turns out that people want to use groups that
229        are longer than 30,000 bytes (though not repeat them that many times).
230        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
231        made it possible to implement the integer overflow checks in a much more
232        dynamic way, which I have now done. The artificial limitation on group
233        length has been removed - we now have only the limit on the total length of
234        the compiled pattern, which depends on the LINK_SIZE setting.
235    
236    10. Fixed a bug in the documentation for get/copy named substring when
237        duplicate names are permitted. If none of the named substrings are set, the
238        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
239        empty string.
240    
241    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
242        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
243        because the ] is interpreted as the first data character and the
244        terminating ] is not found. PCRE has been made compatible with Perl in this
245        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
246        cause memory overwriting.
247    
248    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
249        string has been matched (to stop an infinite loop). It was not recognizing
250        a conditional subpattern that could match an empty string if that
251        subpattern was within another subpattern. For example, it looped when
252        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
253        condition was not nested. This bug has been fixed.
254    
255    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
256        past the start of the subject in the presence of bytes with the top bit
257        set, for example "\x8aBCD".
258    
259    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
260        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
261    
262    14. Optimized (?!) to (*FAIL).
263    
264    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
265        This restricts code points to be within the range 0 to 0x10FFFF, excluding
266        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
267        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
268        does: it's just the validity check that is more restrictive.
269    
270    16. Inserted checks for integer overflows during escape sequence (backslash)
271        processing, and also fixed erroneous offset values for syntax errors during
272        backslash processing.
273    
274    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
275        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
276    
277    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
278        caused an overrun.
279    
280    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
281        something other than just ASCII characters) inside a group that had an
282        unlimited repeat caused a loop at compile time (while checking to see
283        whether the group could match an empty string).
284    
285    20. Debugging a pattern containing \p or \P could cause a crash. For example,
286        [\P{Any}] did so. (Error in the code for printing property names.)
287    
288    21. An orphan \E inside a character class could cause a crash.
289    
290    22. A repeated capturing bracket such as (A)? could cause a wild memory
291        reference during compilation.
292    
293    23. There are several functions in pcre_compile() that scan along a compiled
294        expression for various reasons (e.g. to see if it's fixed length for look
295        behind). There were bugs in these functions when a repeated \p or \P was
296        present in the pattern. These operators have additional parameters compared
297        with \d, etc, and these were not being taken into account when moving along
298        the compiled data. Specifically:
299    
300        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
301            length.
302    
303        (b) An item such as \pL+ within a repeated group could cause crashes or
304            loops.
305    
306        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
307            "reference to non-existent subpattern" error.
308    
309        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
310    
311    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
312        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
313    
314    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
315    
316    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
317        character were causing crashes (broken optimization).
318    
319    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
320        \p or \P) caused a compile-time loop.
321    
322    28. More problems have arisen in unanchored patterns when CRLF is a valid line
323        break. For example, the unstudied pattern [\r\n]A does not match the string
324        "\r\nA" because change 7.0/46 below moves the current point on by two
325        characters after failing to match at the start. However, the pattern \nA
326        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
327        the same is true. There doesn't seem any very clean way out of this, but
328        what I have chosen to do makes the common cases work: PCRE now takes note
329        of whether there can be an explicit match for \r or \n anywhere in the
330        pattern, and if so, 7.0/46 no longer applies. As part of this change,
331        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
332        pattern has explicit CR or LF references.
333    
334    29. Added (*CR) etc for changing newline setting at start of pattern.
335    
336    
337    Version 7.2 19-Jun-07
338    ---------------------
339    
340     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
341        which is apparently normally available under Windows.
342    
343     2. Re-jig the pcregrep tests with different newline settings in an attempt
344        to make them independent of the local environment's newline setting.
345    
346     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
347    
348     4. Some of the "internals" tests were previously cut out when the link size
349        was not 2, because the output contained actual offsets. The recent new
350        "Z" feature of pcretest means that these can be cut out, making the tests
351        usable with all link sizes.
352    
353     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
354        stack recursion. This gives a massive performance boost under BSD, but just
355        a small improvement under Linux. However, it saves one field in the frame
356        in all cases.
357    
358     6. Added more features from the forthcoming Perl 5.10:
359    
360        (a) (?-n) (where n is a string of digits) is a relative subroutine or
361            recursion call. It refers to the nth most recently opened parentheses.
362    
363        (b) (?+n) is also a relative subroutine call; it refers to the nth next
364            to be opened parentheses.
365    
366        (c) Conditions that refer to capturing parentheses can be specified
367            relatively, for example, (?(-2)... or (?(+3)...
368    
369        (d) \K resets the start of the current match so that everything before
370            is not part of it.
371    
372        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
373    
374        (f) \g{name} is another synonym - part of Perl 5.10's unification of
375            reference syntax.
376    
377        (g) (?| introduces a group in which the numbering of parentheses in each
378            alternative starts with the same number.
379    
380        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
381    
382     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
383        PCRE_INFO_JCHANGED.
384    
385     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
386        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
387        for detecting groups that can match an empty string.
388    
389     9. A pattern with a very large number of alternatives (more than several
390        hundred) was running out of internal workspace during the pre-compile
391        phase, where pcre_compile() figures out how much memory will be needed. A
392        bit of new cunning has reduced the workspace needed for groups with
393        alternatives. The 1000-alternative test pattern now uses 12 bytes of
394        workspace instead of running out of the 4096 that are available.
395    
396    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
397    
398    11. Applied patch from Google to remove an optimization that didn't quite work.
399        The report of the bug said:
400    
401          pcrecpp::RE("a*").FullMatch("aaa") matches, while
402          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
403          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
404    
405    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
406        it matched the wrong number of bytes.
407    
408    
409    Version 7.1 24-Apr-07
410    ---------------------
411    
412     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
413        that is more "standard", making use of automake and other Autotools. There
414        is some re-arrangement of the files and adjustment of comments consequent
415        on this.
416    
417     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
418        for recursive directory scanning broke on some systems because the files
419        are not scanned in any specific order and on different systems the order
420        was different. A call to "sort" has been inserted into RunGrepTest for the
421        approprate test as a short-term fix. In the longer term there may be an
422        alternative.
423    
424     3. I had an email from Eric Raymond about problems translating some of PCRE's
425        man pages to HTML (despite the fact that I distribute HTML pages, some
426        people do their own conversions for various reasons). The problems
427        concerned the use of low-level troff macros .br and .in. I have therefore
428        removed all such uses from the man pages (some were redundant, some could
429        be replaced by .nf/.fi pairs). The 132html script that I use to generate
430        HTML has been updated to handle .nf/.fi and to complain if it encounters
431        .br or .in.
432    
433     4. Updated comments in configure.ac that get placed in config.h.in and also
434        arranged for config.h to be included in the distribution, with the name
435        config.h.generic, for the benefit of those who have to compile without
436        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
437    
438     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
439        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
440        makevp.bat for the current PCRE, using the additional files
441        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
442    
443     6. A Windows user reported a minor discrepancy with test 2, which turned out
444        to be caused by a trailing space on an input line that had got lost in his
445        copy. The trailing space was an accident, so I've just removed it.
446    
447     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
448        that is needed.
449    
450     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
451        as "const" (a) because they are and (b) because it helps the PHP
452        maintainers who have recently made a script to detect big data structures
453        in the php code that should be moved to the .rodata section. I remembered
454        to update Builducptable as well, so it won't revert if ucptable.h is ever
455        re-created.
456    
457     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
458        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
459        order to be able to cut out the UTF-8 tables in the latter when UTF-8
460        support is not required. This saves 1.5-2K of code, which is important in
461        some applications.
462    
463        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
464        so as not to refer to the tables, even though these functions will never be
465        called when UTF-8 support is disabled. Otherwise there are problems with a
466        shared library.
467    
468    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
469    
470        (a) It was defining its arguments as char * instead of void *.
471    
472        (b) It was assuming that all moves were upwards in memory; this was true
473            a long time ago when I wrote it, but is no longer the case.
474    
475        The emulated memove() is provided for those environments that have neither
476        memmove() nor bcopy(). I didn't think anyone used it these days, but that
477        is clearly not the case, as these two bugs were recently reported.
478    
479    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
480        and Detrail to create the HTML documentation, the .txt form of the man
481        pages, and it removes trailing spaces from listed files. It also creates
482        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
483        case, it wraps all the #defines with #ifndefs. This script should be run
484        before "make dist".
485    
486    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
487        with Unicode property support.
488    
489        (a) For a maximizing quantifier, if the two different cases of the
490            character were of different lengths in their UTF-8 codings (there are
491            some cases like this - I found 11), and the matching function had to
492            back up over a mixture of the two cases, it incorrectly assumed they
493            were both the same length.
494    
495        (b) When PCRE was configured to use the heap rather than the stack for
496            recursion during matching, it was not correctly preserving the data for
497            the other case of a UTF-8 character when checking ahead for a match
498            while processing a minimizing repeat. If the check also involved
499            matching a wide character, but failed, corruption could cause an
500            erroneous result when trying to check for a repeat of the original
501            character.
502    
503    13. Some tidying changes to the testing mechanism:
504    
505        (a) The RunTest script now detects the internal link size and whether there
506            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
507            values substituted by "configure". (The RunGrepTest script already did
508            this for UTF-8.) The configure.ac script no longer substitutes the
509            relevant variables.
510    
511        (b) The debugging options /B and /D in pcretest show the compiled bytecode
512            with length and offset values. This means that the output is different
513            for different internal link sizes. Test 2 is skipped for link sizes
514            other than 2 because of this, bypassing the problem. Unfortunately,
515            there was also a test in test 3 (the locale tests) that used /B and
516            failed for link sizes other than 2. Rather than cut the whole test out,
517            I have added a new /Z option to pcretest that replaces the length and
518            offset values with spaces. This is now used to make test 3 independent
519            of link size. (Test 2 will be tidied up later.)
520    
521    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
522        segmentation fault instead of returning the appropriate error message.
523    
524    15. In multiline mode when the newline sequence was set to "any", the pattern
525        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
526        This doesn't seem right; it now treats the CRLF combination as the line
527        ending, and so does not match in that case. It's only a pattern such as ^$
528        that would hit this one: something like ^ABC$ would have failed after \r
529        and then tried again after \r\n.
530    
531    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
532        in an attempt to make files that differ only in their line terminators
533        compare equal. This works on Linux.
534    
535    17. Under certain error circumstances pcregrep might try to free random memory
536        as it exited. This is now fixed, thanks to valgrind.
537    
538    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
539        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
540        was because its rules for how to advance for /g after matching an empty
541        string at the end of a line did not allow for this case. They now check for
542        it specially.
543    
544    20. pcretest is supposed to handle patterns and data of any length, by
545        extending its buffers when necessary. It was getting this wrong when the
546        buffer for a data line had to be extended.
547    
548    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
549        CRLF as a newline sequence.
550    
551    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
552        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
553        I have nevertheless tidied it up.
554    
555    23. Added some casts to kill warnings from HP-UX ia64 compiler.
556    
557    24. Added a man page for pcre-config.
558    
559    
560    Version 7.0 19-Dec-06
561    ---------------------
562    
563     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
564        moving to gcc 4.1.1.
565    
566     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
567        sys/time.h, which is documented as needed for this function. It doesn't
568        seem to matter on Linux, but it showed up on some releases of OS X.
569    
570     3. It seems that there are systems where bytes whose values are greater than
571        127 match isprint() in the "C" locale. The "C" locale should be the
572        default when a C program starts up. In most systems, only ASCII printing
573        characters match isprint(). This difference caused the output from pcretest
574        to vary, making some of the tests fail. I have changed pcretest so that:
575    
576        (a) When it is outputting text in the compiled version of a pattern, bytes
577            other than 32-126 are always shown as hex escapes.
578    
579        (b) When it is outputting text that is a matched part of a subject string,
580            it does the same, unless a different locale has been set for the match
581            (using the /L modifier). In this case, it uses isprint() to decide.
582    
583     4. Fixed a major bug that caused incorrect computation of the amount of memory
584        required for a compiled pattern when options that changed within the
585        pattern affected the logic of the preliminary scan that determines the
586        length. The relevant options are -x, and -i in UTF-8 mode. The result was
587        that the computed length was too small. The symptoms of this bug were
588        either the PCRE error "internal error: code overflow" from pcre_compile(),
589        or a glibc crash with a message such as "pcretest: free(): invalid next
590        size (fast)". Examples of patterns that provoked this bug (shown in
591        pcretest format) are:
592    
593          /(?-x: )/x
594          /(?x)(?-x: \s*#\s*)/
595          /((?i)[\x{c0}])/8
596          /(?i:[\x{c0}])/8
597    
598        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
599        is now done differently.
600    
601     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
602        wrapper classes; (b) implement a new function in the C++ scanner that is
603        more efficient than the old way of doing things because it avoids levels of
604        recursion in the regex matching; (c) add a paragraph to the documentation
605        for the FullMatch() function.
606    
607     6. The escape sequence \n was being treated as whatever was defined as
608        "newline". Not only was this contrary to the documentation, which states
609        that \n is character 10 (hex 0A), but it also went horribly wrong when
610        "newline" was defined as CRLF. This has been fixed.
611    
612     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
613        was being set to -1 for the "end of line" case (supposedly a value that no
614        character can have). Though this value is never used (the check for end of
615        line is "zero bytes in current character"), it caused compiler complaints.
616        I've changed it to 0xffffffff.
617    
618     8. In pcre_version.c, the version string was being built by a sequence of
619        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
620        string (as it is for production releases) called a macro with an empty
621        argument. The C standard says the result of this is undefined. The gcc
622        compiler treats it as an empty string (which was what was wanted) but it is
623        reported that Visual C gives an error. The source has been hacked around to
624        avoid this problem.
625    
626     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
627        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
628        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
629        of them did).
630    
631    10. Originally, pcretest opened its input and output without "b"; then I was
632        told that "b" was needed in some environments, so it was added for release
633        5.0 to both the input and output. (It makes no difference on Unix-like
634        systems.) Later I was told that it is wrong for the input on Windows. I've
635        now abstracted the modes into two macros, to make it easier to fiddle with
636        them, and removed "b" from the input mode under Windows.
637    
638    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
639    
640    12. Added -help and --help to pcretest as an official way of being reminded
641        of the options.
642    
643    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
644        and pcrecpp.cc because they annoy compilers at high warning levels.
645    
646    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
647    
648    15. Fixed an occurrence of == in configure.ac that should have been = (shell
649        scripts are not C programs :-) and which was not noticed because it works
650        on Linux.
651    
652    16. pcretest is supposed to handle any length of pattern and data line (as one
653        line or as a continued sequence of lines) by extending its input buffer if
654        necessary. This feature was broken for very long pattern lines, leading to
655        a string of junk being passed to pcre_compile() if the pattern was longer
656        than about 50K.
657    
658    17. I have done a major re-factoring of the way pcre_compile() computes the
659        amount of memory needed for a compiled pattern. Previously, there was code
660        that made a preliminary scan of the pattern in order to do this. That was
661        OK when PCRE was new, but as the facilities have expanded, it has become
662        harder and harder to keep it in step with the real compile phase, and there
663        have been a number of bugs (see for example, 4 above). I have now found a
664        cunning way of running the real compile function in a "fake" mode that
665        enables it to compute how much memory it would need, while actually only
666        ever using a few hundred bytes of working memory and without too many
667        tests of the mode. This should make future maintenance and development
668        easier. A side effect of this work is that the limit of 200 on the nesting
669        depth of parentheses has been removed (though this was never a serious
670        limitation, I suspect). However, there is a downside: pcre_compile() now
671        runs more slowly than before (30% or more, depending on the pattern). I
672        hope this isn't a big issue. There is no effect on runtime performance.
673    
674    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
675        newline (only possible for the last line of a file) and it was a
676        pattern that set a locale (followed by /Lsomething), pcretest crashed.
677    
678    19. Added additional timing features to pcretest. (1) The -tm option now times
679        matching only, not compiling. (2) Both -t and -tm can be followed, as a
680        separate command line item, by a number that specifies the number of
681        repeats to use when timing. The default is 50000; this gives better
682        precision, but takes uncomfortably long for very large patterns.
683    
684    20. Extended pcre_study() to be more clever in cases where a branch of a
685        subpattern has no definite first character. For example, (a*|b*)[cd] would
686        previously give no result from pcre_study(). Now it recognizes that the
687        first character must be a, b, c, or d.
688    
689    21. There was an incorrect error "recursive call could loop indefinitely" if
690        a subpattern (or the entire pattern) that was being tested for matching an
691        empty string contained only one non-empty item after a nested subpattern.
692        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
693        incorrectly, because the \d was being skipped in the check.
694    
695    22. The pcretest program now has a new pattern option /B and a command line
696        option -b, which is equivalent to adding /B to every pattern. This causes
697        it to show the compiled bytecode, without the additional information that
698        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
699        is the same as /B/I).
700    
701    23. A new optimization is now able automatically to treat some sequences such
702        as a*b as a*+b. More specifically, if something simple (such as a character
703        or a simple class like \d) has an unlimited quantifier, and is followed by
704        something that cannot possibly match the quantified thing, the quantifier
705        is automatically "possessified".
706    
707    24. A recursive reference to a subpattern whose number was greater than 39
708        went wrong under certain circumstances in UTF-8 mode. This bug could also
709        have affected the operation of pcre_study().
710    
711    25. Realized that a little bit of performance could be had by replacing
712        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
713    
714    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
715    
716    27. Possessive quantifiers such as a++ were previously implemented by turning
717        them into atomic groups such as ($>a+). Now they have their own opcodes,
718        which improves performance. This includes the automatically created ones
719        from 23 above.
720    
721    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
722        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
723        the first matched character to be a colon. This applied both to named and
724        numbered groups.
725    
726    29. The ucpinternal.h header file was missing its idempotency #ifdef.
727    
728    30. I was sent a "project" file called libpcre.a.dev which I understand makes
729        building PCRE on Windows easier, so I have included it in the distribution.
730    
731    31. There is now a check in pcretest against a ridiculously large number being
732        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
733        loop, the loop is abandoned.
734    
735    32. Forward references to subpatterns in conditions such as (?(2)...) where
736        subpattern 2 is defined later cause pcre_compile() to search forwards in
737        the pattern for the relevant set of parentheses. This search went wrong
738        when there were unescaped parentheses in a character class, parentheses
739        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
740    
741    33. "Subroutine" calls and backreferences were previously restricted to
742        referencing subpatterns earlier in the regex. This restriction has now
743        been removed.
744    
745    34. Added a number of extra features that are going to be in Perl 5.10. On the
746        whole, these are just syntactic alternatives for features that PCRE had
747        previously implemented using the Python syntax or my own invention. The
748        other formats are all retained for compatibility.
749    
750        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
751            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
752            also .NET compatible.
753    
754        (b) A recursion or subroutine call to a named group can now be defined as
755            (?&name) as well as (?P>name).
756    
757        (c) A backreference to a named group can now be defined as \k<name> or
758            \k'name' as well as (?P=name). The new forms, as well as being in Perl
759            5.10, are also .NET compatible.
760    
761        (d) A conditional reference to a named group can now use the syntax
762            (?(<name>) or (?('name') as well as (?(name).
763    
764        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
765            groups (named and numbered) that are never evaluated inline, but can be
766            called as "subroutines" from elsewhere. In effect, the DEFINE condition
767            is always false. There may be only one alternative in such a group.
768    
769        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
770            as the simple (?(R). The condition is true only if the most recent
771            recursion is that of the given number or name. It does not search out
772            through the entire recursion stack.
773    
774        (g) The escape \gN or \g{N} has been added, where N is a positive or
775            negative number, specifying an absolute or relative reference.
776    
777    35. Tidied to get rid of some further signed/unsigned compiler warnings and
778        some "unreachable code" warnings.
779    
780    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
781        things, this adds five new scripts.
782    
783    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
784        There were also incompatibilities regarding the handling of \Q..\E inside
785        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
786        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
787    
788    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
789        matches an empty string, and forcibly breaks the loop. There were bugs in
790        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
791        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
792        separate and independent bugs (that affected different cases) have been
793        fixed.
794    
795    39. Refactored the code to abolish the use of different opcodes for small
796        capturing bracket numbers. This is a tidy that I avoided doing when I
797        removed the limit on the number of capturing brackets for 3.5 back in 2001.
798        The new approach is not only tidier, it makes it possible to reduce the
799        memory needed to fix the previous bug (38).
800    
801    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
802        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
803        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
804        mode.
805    
806    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
807        report.
808    
809    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
810        copy construction and assignment in the C++ wrapper.
811    
812    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
813        couple of bugs that could have given wrong results in the "--newline=crlf"
814        case.
815    
816    44. Added a number of casts and did some reorganization of signed/unsigned int
817        variables following suggestions from Dair Grant. Also renamed the variable
818        "this" as "item" because it is a C++ keyword.
819    
820    45. Arranged for dftables to add
821    
822          #include "pcre_internal.h"
823    
824        to pcre_chartables.c because without it, gcc 4.x may remove the array
825        definition from the final binary if PCRE is built into a static library and
826        dead code stripping is activated.
827    
828    46. For an unanchored pattern, if a match attempt fails at the start of a
829        newline sequence, and the newline setting is CRLF or ANY, and the next two
830        characters are CRLF, advance by two characters instead of one.
831    
832    
833    Version 6.7 04-Jul-06
834    ---------------------
835    
836     1. In order to handle tests when input lines are enormously long, pcretest has
837        been re-factored so that it automatically extends its buffers when
838        necessary. The code is crude, but this _is_ just a test program. The
839        default size has been increased from 32K to 50K.
840    
841     2. The code in pcre_study() was using the value of the re argument before
842        testing it for NULL. (Of course, in any sensible call of the function, it
843        won't be NULL.)
844    
845     3. The memmove() emulation function in pcre_internal.h, which is used on
846        systems that lack both memmove() and bcopy() - that is, hardly ever -
847        was missing a "static" storage class specifier.
848    
849     4. When UTF-8 mode was not set, PCRE looped when compiling certain patterns
850        containing an extended class (one that cannot be represented by a bitmap
851        because it contains high-valued characters or Unicode property items, e.g.
852        [\pZ]). Almost always one would set UTF-8 mode when processing such a
853        pattern, but PCRE should not loop if you do not (it no longer does).
854        [Detail: two cases were found: (a) a repeated subpattern containing an
855        extended class; (b) a recursive reference to a subpattern that followed a
856        previous extended class. It wasn't skipping over the extended class
857        correctly when UTF-8 mode was not set.]
858    
859     5. A negated single-character class was not being recognized as fixed-length
860        in lookbehind assertions such as (?<=[^f]), leading to an incorrect
861        compile error "lookbehind assertion is not fixed length".
862    
863     6. The RunPerlTest auxiliary script was showing an unexpected difference
864        between PCRE and Perl for UTF-8 tests. It turns out that it is hard to
865        write a Perl script that can interpret lines of an input file either as
866        byte characters or as UTF-8, which is what "perltest" was being required to
867        do for the non-UTF-8 and UTF-8 tests, respectively. Essentially what you
868        can't do is switch easily at run time between having the "use utf8;" pragma
869        or not. In the end, I fudged it by using the RunPerlTest script to insert
870        "use utf8;" explicitly for the UTF-8 tests.
871    
872     7. In multiline (/m) mode, PCRE was matching ^ after a terminating newline at
873        the end of the subject string, contrary to the documentation and to what
874        Perl does. This was true of both matching functions. Now it matches only at
875        the start of the subject and immediately after *internal* newlines.
876    
877     8. A call of pcre_fullinfo() from pcretest to get the option bits was passing
878        a pointer to an int instead of a pointer to an unsigned long int. This
879        caused problems on 64-bit systems.
880    
881     9. Applied a patch from the folks at Google to pcrecpp.cc, to fix "another
882        instance of the 'standard' template library not being so standard".
883    
884    10. There was no check on the number of named subpatterns nor the maximum
885        length of a subpattern name. The product of these values is used to compute
886        the size of the memory block for a compiled pattern. By supplying a very
887        long subpattern name and a large number of named subpatterns, the size
888        computation could be caused to overflow. This is now prevented by limiting
889        the length of names to 32 characters, and the number of named subpatterns
890        to 10,000.
891    
892    11. Subpatterns that are repeated with specific counts have to be replicated in
893        the compiled pattern. The size of memory for this was computed from the
894        length of the subpattern and the repeat count. The latter is limited to
895        65535, but there was no limit on the former, meaning that integer overflow
896        could in principle occur. The compiled length of a repeated subpattern is
897        now limited to 30,000 bytes in order to prevent this.
898    
899    12. Added the optional facility to have named substrings with the same name.
900    
901    13. Added the ability to use a named substring as a condition, using the
902        Python syntax: (?(name)yes|no). This overloads (?(R)... and names that
903        are numbers (not recommended). Forward references are permitted.
904    
905    14. Added forward references in named backreferences (if you see what I mean).
906    
907    15. In UTF-8 mode, with the PCRE_DOTALL option set, a quantified dot in the
908        pattern could run off the end of the subject. For example, the pattern
909        "(?s)(.{1,5})"8 did this with the subject "ab".
910    
911    16. If PCRE_DOTALL or PCRE_MULTILINE were set, pcre_dfa_exec() behaved as if
912        PCRE_CASELESS was set when matching characters that were quantified with ?
913        or *.
914    
915    17. A character class other than a single negated character that had a minimum
916        but no maximum quantifier - for example [ab]{6,} - was not handled
917        correctly by pce_dfa_exec(). It would match only one character.
918    
919    18. A valid (though odd) pattern that looked like a POSIX character
920        class but used an invalid character after [ (for example [[,abc,]]) caused
921        pcre_compile() to give the error "Failed: internal error: code overflow" or
922        in some cases to crash with a glibc free() error. This could even happen if
923        the pattern terminated after [[ but there just happened to be a sequence of
924        letters, a binary zero, and a closing ] in the memory that followed.
925    
926    19. Perl's treatment of octal escapes in the range \400 to \777 has changed
927        over the years. Originally (before any Unicode support), just the bottom 8
928        bits were taken. Thus, for example, \500 really meant \100. Nowadays the
929        output from "man perlunicode" includes this:
930    
931          The regular expression compiler produces polymorphic opcodes.  That
932          is, the pattern adapts to the data and automatically switches to
933          the Unicode character scheme when presented with Unicode data--or
934          instead uses a traditional byte scheme when presented with byte
935          data.
936    
937        Sadly, a wide octal escape does not cause a switch, and in a string with
938        no other multibyte characters, these octal escapes are treated as before.
939        Thus, in Perl, the pattern  /\500/ actually matches \100 but the pattern
940        /\500|\x{1ff}/ matches \500 or \777 because the whole thing is treated as a
941        Unicode string.
942    
943        I have not perpetrated such confusion in PCRE. Up till now, it took just
944        the bottom 8 bits, as in old Perl. I have now made octal escapes with
945        values greater than \377 illegal in non-UTF-8 mode. In UTF-8 mode they
946        translate to the appropriate multibyte character.
947    
948    29. Applied some refactoring to reduce the number of warnings from Microsoft
949        and Borland compilers. This has included removing the fudge introduced
950        seven years ago for the OS/2 compiler (see 2.02/2 below) because it caused
951        a warning about an unused variable.
952    
953    21. PCRE has not included VT (character 0x0b) in the set of whitespace
954        characters since release 4.0, because Perl (from release 5.004) does not.
955        [Or at least, is documented not to: some releases seem to be in conflict
956        with the documentation.] However, when a pattern was studied with
957        pcre_study() and all its branches started with \s, PCRE still included VT
958        as a possible starting character. Of course, this did no harm; it just
959        caused an unnecessary match attempt.
960    
961    22. Removed a now-redundant internal flag bit that recorded the fact that case
962        dependency changed within the pattern. This was once needed for "required
963        byte" processing, but is no longer used. This recovers a now-scarce options
964        bit. Also moved the least significant internal flag bit to the most-
965        significant bit of the word, which was not previously used (hangover from
966        the days when it was an int rather than a uint) to free up another bit for
967        the future.
968    
969    23. Added support for CRLF line endings as well as CR and LF. As well as the
970        default being selectable at build time, it can now be changed at runtime
971        via the PCRE_NEWLINE_xxx flags. There are now options for pcregrep to
972        specify that it is scanning data with non-default line endings.
973    
974    24. Changed the definition of CXXLINK to make it agree with the definition of
975        LINK in the Makefile, by replacing LDFLAGS to CXXFLAGS.
976    
977    25. Applied Ian Taylor's patches to avoid using another stack frame for tail
978        recursions. This makes a big different to stack usage for some patterns.
979    
980    26. If a subpattern containing a named recursion or subroutine reference such
981        as (?P>B) was quantified, for example (xxx(?P>B)){3}, the calculation of
982        the space required for the compiled pattern went wrong and gave too small a
983        value. Depending on the environment, this could lead to "Failed: internal
984        error: code overflow at offset 49" or "glibc detected double free or
985        corruption" errors.
986    
987    27. Applied patches from Google (a) to support the new newline modes and (b) to
988        advance over multibyte UTF-8 characters in GlobalReplace.
989    
990    28. Change free() to pcre_free() in pcredemo.c. Apparently this makes a
991        difference for some implementation of PCRE in some Windows version.
992    
993    29. Added some extra testing facilities to pcretest:
994    
995        \q<number>   in a data line sets the "match limit" value
996        \Q<number>   in a data line sets the "match recursion limt" value
997        -S <number>  sets the stack size, where <number> is in megabytes
998    
999        The -S option isn't available for Windows.
1000    
1001    
1002    Version 6.6 06-Feb-06
1003    ---------------------
1004    
1005     1. Change 16(a) for 6.5 broke things, because PCRE_DATA_SCOPE was not defined
1006        in pcreposix.h. I have copied the definition from pcre.h.
1007    
1008     2. Change 25 for 6.5 broke compilation in a build directory out-of-tree
1009        because pcre.h is no longer a built file.
1010    
1011     3. Added Jeff Friedl's additional debugging patches to pcregrep. These are
1012        not normally included in the compiled code.
1013    
1014    
1015    Version 6.5 01-Feb-06
1016    ---------------------
1017    
1018     1. When using the partial match feature with pcre_dfa_exec(), it was not
1019        anchoring the second and subsequent partial matches at the new starting
1020        point. This could lead to incorrect results. For example, with the pattern
1021        /1234/, partially matching against "123" and then "a4" gave a match.
1022    
1023     2. Changes to pcregrep:
1024    
1025        (a) All non-match returns from pcre_exec() were being treated as failures
1026            to match the line. Now, unless the error is PCRE_ERROR_NOMATCH, an
1027            error message is output. Some extra information is given for the
1028            PCRE_ERROR_MATCHLIMIT and PCRE_ERROR_RECURSIONLIMIT errors, which are
1029            probably the only errors that are likely to be caused by users (by
1030            specifying a regex that has nested indefinite repeats, for instance).
1031            If there are more than 20 of these errors, pcregrep is abandoned.
1032    
1033        (b) A binary zero was treated as data while matching, but terminated the
1034            output line if it was written out. This has been fixed: binary zeroes
1035            are now no different to any other data bytes.
1036    
1037        (c) Whichever of the LC_ALL or LC_CTYPE environment variables is set is
1038            used to set a locale for matching. The --locale=xxxx long option has
1039            been added (no short equivalent) to specify a locale explicitly on the
1040            pcregrep command, overriding the environment variables.
1041    
1042        (d) When -B was used with -n, some line numbers in the output were one less
1043            than they should have been.
1044    
1045        (e) Added the -o (--only-matching) option.
1046    
1047        (f) If -A or -C was used with -c (count only), some lines of context were
1048            accidentally printed for the final match.
1049    
1050        (g) Added the -H (--with-filename) option.
1051    
1052        (h) The combination of options -rh failed to suppress file names for files
1053            that were found from directory arguments.
1054    
1055        (i) Added the -D (--devices) and -d (--directories) options.
1056    
1057        (j) Added the -F (--fixed-strings) option.
1058    
1059        (k) Allow "-" to be used as a file name for -f as well as for a data file.
1060    
1061        (l) Added the --colo(u)r option.
1062    
1063        (m) Added Jeffrey Friedl's -S testing option, but within #ifdefs so that it
1064            is not present by default.
1065    
1066     3. A nasty bug was discovered in the handling of recursive patterns, that is,
1067        items such as (?R) or (?1), when the recursion could match a number of
1068        alternatives. If it matched one of the alternatives, but subsequently,
1069        outside the recursion, there was a failure, the code tried to back up into
1070        the recursion. However, because of the way PCRE is implemented, this is not
1071        possible, and the result was an incorrect result from the match.
1072    
1073        In order to prevent this happening, the specification of recursion has
1074        been changed so that all such subpatterns are automatically treated as
1075        atomic groups. Thus, for example, (?R) is treated as if it were (?>(?R)).
1076    
1077     4. I had overlooked the fact that, in some locales, there are characters for
1078        which isalpha() is true but neither isupper() nor islower() are true. In
1079        the fr_FR locale, for instance, the \xAA and \xBA characters (ordmasculine
1080        and ordfeminine) are like this. This affected the treatment of \w and \W
1081        when they appeared in character classes, but not when they appeared outside
1082        a character class. The bit map for "word" characters is now created
1083        separately from the results of isalnum() instead of just taking it from the
1084        upper, lower, and digit maps. (Plus the underscore character, of course.)
1085    
1086     5. The above bug also affected the handling of POSIX character classes such as
1087        [[:alpha:]] and [[:alnum:]]. These do not have their own bit maps in PCRE's
1088        permanent tables. Instead, the bit maps for such a class were previously
1089        created as the appropriate unions of the upper, lower, and digit bitmaps.
1090        Now they are created by subtraction from the [[:word:]] class, which has
1091        its own bitmap.
1092    
1093     6. The [[:blank:]] character class matches horizontal, but not vertical space.
1094        It is created by subtracting the vertical space characters (\x09, \x0a,
1095        \x0b, \x0c) from the [[:space:]] bitmap. Previously, however, the
1096        subtraction was done in the overall bitmap for a character class, meaning
1097        that a class such as [\x0c[:blank:]] was incorrect because \x0c would not
1098        be recognized. This bug has been fixed.
1099    
1100     7. Patches from the folks at Google:
1101    
1102          (a) pcrecpp.cc: "to handle a corner case that may or may not happen in
1103          real life, but is still worth protecting against".
1104    
1105          (b) pcrecpp.cc: "corrects a bug when negative radixes are used with
1106          regular expressions".
1107    
1108          (c) pcre_scanner.cc: avoid use of std::count() because not all systems
1109          have it.
1110    
1111          (d) Split off pcrecpparg.h from pcrecpp.h and had the former built by
1112          "configure" and the latter not, in order to fix a problem somebody had
1113          with compiling the Arg class on HP-UX.
1114    
1115          (e) Improve the error-handling of the C++ wrapper a little bit.
1116    
1117          (f) New tests for checking recursion limiting.
1118    
1119     8. The pcre_memmove() function, which is used only if the environment does not
1120        have a standard memmove() function (and is therefore rarely compiled),
1121        contained two bugs: (a) use of int instead of size_t, and (b) it was not
1122        returning a result (though PCRE never actually uses the result).
1123    
1124     9. In the POSIX regexec() interface, if nmatch is specified as a ridiculously
1125        large number - greater than INT_MAX/(3*sizeof(int)) - REG_ESPACE is
1126        returned instead of calling malloc() with an overflowing number that would
1127        most likely cause subsequent chaos.
1128    
1129    10. The debugging option of pcretest was not showing the NO_AUTO_CAPTURE flag.
1130    
1131    11. The POSIX flag REG_NOSUB is now supported. When a pattern that was compiled
1132        with this option is matched, the nmatch and pmatch options of regexec() are
1133        ignored.
1134    
1135    12. Added REG_UTF8 to the POSIX interface. This is not defined by POSIX, but is
1136        provided in case anyone wants to the the POSIX interface with UTF-8
1137        strings.
1138    
1139    13. Added CXXLDFLAGS to the Makefile parameters to provide settings only on the
1140        C++ linking (needed for some HP-UX environments).
1141    
1142    14. Avoid compiler warnings in get_ucpname() when compiled without UCP support
1143        (unused parameter) and in the pcre_printint() function (omitted "default"
1144        switch label when the default is to do nothing).
1145    
1146    15. Added some code to make it possible, when PCRE is compiled as a C++
1147        library, to replace subject pointers for pcre_exec() with a smart pointer
1148        class, thus making it possible to process discontinuous strings.
1149    
1150    16. The two macros PCRE_EXPORT and PCRE_DATA_SCOPE are confusing, and perform
1151        much the same function. They were added by different people who were trying
1152        to make PCRE easy to compile on non-Unix systems. It has been suggested
1153        that PCRE_EXPORT be abolished now that there is more automatic apparatus
1154        for compiling on Windows systems. I have therefore replaced it with
1155        PCRE_DATA_SCOPE. This is set automatically for Windows; if not set it
1156        defaults to "extern" for C or "extern C" for C++, which works fine on
1157        Unix-like systems. It is now possible to override the value of PCRE_DATA_
1158        SCOPE with something explicit in config.h. In addition:
1159    
1160        (a) pcreposix.h still had just "extern" instead of either of these macros;
1161            I have replaced it with PCRE_DATA_SCOPE.
1162    
1163        (b) Functions such as _pcre_xclass(), which are internal to the library,
1164            but external in the C sense, all had PCRE_EXPORT in their definitions.
1165            This is apparently wrong for the Windows case, so I have removed it.
1166            (It makes no difference on Unix-like systems.)
1167    
1168    17. Added a new limit, MATCH_LIMIT_RECURSION, which limits the depth of nesting
1169        of recursive calls to match(). This is different to MATCH_LIMIT because
1170        that limits the total number of calls to match(), not all of which increase
1171        the depth of recursion. Limiting the recursion depth limits the amount of
1172        stack (or heap if NO_RECURSE is set) that is used. The default can be set
1173        when PCRE is compiled, and changed at run time. A patch from Google adds
1174        this functionality to the C++ interface.
1175    
1176    18. Changes to the handling of Unicode character properties:
1177    
1178        (a) Updated the table to Unicode 4.1.0.
1179    
1180        (b) Recognize characters that are not in the table as "Cn" (undefined).
1181    
1182        (c) I revised the way the table is implemented to a much improved format
1183            which includes recognition of ranges. It now supports the ranges that
1184            are defined in UnicodeData.txt, and it also amalgamates other
1185            characters into ranges. This has reduced the number of entries in the
1186            table from around 16,000 to around 3,000, thus reducing its size
1187            considerably. I realized I did not need to use a tree structure after
1188            all - a binary chop search is just as efficient. Having reduced the
1189            number of entries, I extended their size from 6 bytes to 8 bytes to
1190            allow for more data.
1191    
1192        (d) Added support for Unicode script names via properties such as \p{Han}.
1193    
1194    19. In UTF-8 mode, a backslash followed by a non-Ascii character was not
1195        matching that character.
1196    
1197    20. When matching a repeated Unicode property with a minimum greater than zero,
1198        (for example \pL{2,}), PCRE could look past the end of the subject if it
1199        reached it while seeking the minimum number of characters. This could
1200        happen only if some of the characters were more than one byte long, because
1201        there is a check for at least the minimum number of bytes.
1202    
1203    21. Refactored the implementation of \p and \P so as to be more general, to
1204        allow for more different types of property in future. This has changed the
1205        compiled form incompatibly. Anybody with saved compiled patterns that use
1206        \p or \P will have to recompile them.
1207    
1208    22. Added "Any" and "L&" to the supported property types.
1209    
1210    23. Recognize \x{...} as a code point specifier, even when not in UTF-8 mode,
1211        but give a compile time error if the value is greater than 0xff.
1212    
1213    24. The man pages for pcrepartial, pcreprecompile, and pcre_compile2 were
1214        accidentally not being installed or uninstalled.
1215    
1216    25. The pcre.h file was built from pcre.h.in, but the only changes that were
1217        made were to insert the current release number. This seemed silly, because
1218        it made things harder for people building PCRE on systems that don't run
1219        "configure". I have turned pcre.h into a distributed file, no longer built
1220        by "configure", with the version identification directly included. There is
1221        no longer a pcre.h.in file.
1222    
1223        However, this change necessitated a change to the pcre-config script as
1224        well. It is built from pcre-config.in, and one of the substitutions was the
1225        release number. I have updated configure.ac so that ./configure now finds
1226        the release number by grepping pcre.h.
1227    
1228    26. Added the ability to run the tests under valgrind.
1229    
1230    
1231    Version 6.4 05-Sep-05
1232    ---------------------
1233    
1234     1. Change 6.0/10/(l) to pcregrep introduced a bug that caused separator lines
1235        "--" to be printed when multiple files were scanned, even when none of the
1236        -A, -B, or -C options were used. This is not compatible with Gnu grep, so I
1237        consider it to be a bug, and have restored the previous behaviour.
1238    
1239     2. A couple of code tidies to get rid of compiler warnings.
1240    
1241     3. The pcretest program used to cheat by referring to symbols in the library
1242        whose names begin with _pcre_. These are internal symbols that are not
1243        really supposed to be visible externally, and in some environments it is
1244        possible to suppress them. The cheating is now confined to including
1245        certain files from the library's source, which is a bit cleaner.
1246    
1247     4. Renamed pcre.in as pcre.h.in to go with pcrecpp.h.in; it also makes the
1248        file's purpose clearer.
1249    
1250     5. Reorganized pcre_ucp_findchar().
1251    
1252    
1253    Version 6.3 15-Aug-05
1254    ---------------------
1255    
1256     1. The file libpcre.pc.in did not have general read permission in the tarball.
1257    
1258     2. There were some problems when building without C++ support:
1259    
1260        (a) If C++ support was not built, "make install" and "make test" still
1261            tried to test it.
1262    
1263        (b) There were problems when the value of CXX was explicitly set. Some
1264            changes have been made to try to fix these, and ...
1265    
1266        (c) --disable-cpp can now be used to explicitly disable C++ support.
1267    
1268        (d) The use of @CPP_OBJ@ directly caused a blank line preceded by a
1269            backslash in a target when C++ was disabled. This confuses some
1270            versions of "make", apparently. Using an intermediate variable solves
1271            this. (Same for CPP_LOBJ.)
1272    
1273     3. $(LINK_FOR_BUILD) now includes $(CFLAGS_FOR_BUILD) and $(LINK)
1274        (non-Windows) now includes $(CFLAGS) because these flags are sometimes
1275        necessary on certain architectures.
1276    
1277     4. Added a setting of -export-symbols-regex to the link command to remove
1278        those symbols that are exported in the C sense, but actually are local
1279        within the library, and not documented. Their names all begin with
1280        "_pcre_". This is not a perfect job, because (a) we have to except some
1281        symbols that pcretest ("illegally") uses, and (b) the facility isn't always
1282        available (and never for static libraries). I have made a note to try to
1283        find a way round (a) in the future.
1284    
1285    
1286    Version 6.2 01-Aug-05
1287    ---------------------
1288    
1289     1. There was no test for integer overflow of quantifier values. A construction
1290        such as {1111111111111111} would give undefined results. What is worse, if
1291        a minimum quantifier for a parenthesized subpattern overflowed and became
1292        negative, the calculation of the memory size went wrong. This could have
1293        led to memory overwriting.
1294    
1295     2. Building PCRE using VPATH was broken. Hopefully it is now fixed.
1296    
1297     3. Added "b" to the 2nd argument of fopen() in dftables.c, for non-Unix-like
1298        operating environments where this matters.
1299    
1300     4. Applied Giuseppe Maxia's patch to add additional features for controlling
1301        PCRE options from within the C++ wrapper.
1302    
1303     5. Named capturing subpatterns were not being correctly counted when a pattern
1304        was compiled. This caused two problems: (a) If there were more than 100
1305        such subpatterns, the calculation of the memory needed for the whole
1306        compiled pattern went wrong, leading to an overflow error. (b) Numerical
1307        back references of the form \12, where the number was greater than 9, were
1308        not recognized as back references, even though there were sufficient
1309        previous subpatterns.
1310    
1311     6. Two minor patches to pcrecpp.cc in order to allow it to compile on older
1312        versions of gcc, e.g. 2.95.4.
1313    
1314    
1315    Version 6.1 21-Jun-05
1316    ---------------------
1317    
1318     1. There was one reference to the variable "posix" in pcretest.c that was not
1319        surrounded by "#if !defined NOPOSIX".
1320    
1321     2. Make it possible to compile pcretest without DFA support, UTF8 support, or
1322        the cross-check on the old pcre_info() function, for the benefit of the
1323        cut-down version of PCRE that is currently imported into Exim.
1324    
1325     3. A (silly) pattern starting with (?i)(?-i) caused an internal space
1326        allocation error. I've done the easy fix, which wastes 2 bytes for sensible
1327        patterns that start (?i) but I don't think that matters. The use of (?i) is
1328        just an example; this all applies to the other options as well.
1329    
1330     4. Since libtool seems to echo the compile commands it is issuing, the output
1331        from "make" can be reduced a bit by putting "@" in front of each libtool
1332        compile command.
1333    
1334     5. Patch from the folks at Google for configure.in to be a bit more thorough
1335        in checking for a suitable C++ installation before trying to compile the
1336        C++ stuff. This should fix a reported problem when a compiler was present,
1337        but no suitable headers.
1338    
1339     6. The man pages all had just "PCRE" as their title. I have changed them to
1340        be the relevant file name. I have also arranged that these names are
1341        retained in the file doc/pcre.txt, which is a concatenation in text format
1342        of all the man pages except the little individual ones for each function.
1343    
1344     7. The NON-UNIX-USE file had not been updated for the different set of source
1345        files that come with release 6. I also added a few comments about the C++
1346        wrapper.
1347    
1348    
1349  Version 6.0 07-Jun-05  Version 6.0 07-Jun-05
1350  ---------------------  ---------------------
1351    

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