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revision 91 by nigel, Sat Feb 24 21:41:34 2007 UTC revision 314 by ph10, Fri Jan 25 17:09:21 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 7.6 21-Jan-08
5    ---------------------
6    
7    1.  A character class containing a very large number of characters with
8        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
9        overflow.
10    
11    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
12        HAVE_LONG_LONG is not defined.
13    
14    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
15        bring them up to date and include new features. This patch includes:
16    
17        - Fixed PH's badly added libz and libbz2 support.
18        - Fixed a problem with static linking.
19        - Added pcredemo. [But later removed - see 7 below.]
20        - Fixed dftables problem and added an option.
21        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
22            HAVE_LONG_LONG.
23        - Added readline support for pcretest.
24        - Added an listing of the option settings after cmake has run.
25    
26    4.  A user submitted a patch to Makefile that makes it easy to create
27        "pcre.dll" under mingw when using Configure/Make. I added stuff to
28        Makefile.am that cause it to include this special target, without
29        affecting anything else. Note that the same mingw target plus all
30        the other distribution libraries and programs are now supported
31        when configuring with CMake (see 6 below) instead of with
32        Configure/Make.
33    
34    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
35        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
36        exported in the Windows port". It has not yet been confirmed that the patch
37        solves the problem, but it does no harm.
38    
39    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
40        NON_STANDARD_LIB_SUFFIX for dll names built with mingw when configured
41        with CMake, and also correct the comment about stack recursion.
42    
43    7.  Remove the automatic building of pcredemo from the ./configure system and
44        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
45        of a program that users should build themselves after PCRE is installed, so
46        building it automatically is not really right. What is more, it gave
47        trouble in some build environments.
48    
49    
50    Version 7.5 10-Jan-08
51    ---------------------
52    
53    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
54        values in parens when parsing an RE using the C++ wrapper."
55    
56    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
57        Characters greater than 255 were excluded from the class instead of being
58        included.
59    
60    3.  The same bug as (2) above applied to negated POSIX classes such as
61        [:^space:].
62    
63    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
64        defined or documented. It seems to have been a typo for PCRE_STATIC, so
65        I have changed it.
66    
67    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
68        first named subpattern) and a construct such as (?&a) would reference the
69        first named subpattern whose name started with "a" (in other words, the
70        length check was missing). Both these problems are fixed. "Subpattern name
71        expected" is now given for (?&) (a zero-length name), and this patch also
72        makes it give the same error for \k'' (previously it complained that that
73        was a reference to a non-existent subpattern).
74    
75    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
76        this is right because (?- can be followed by option settings as well as by
77        digits. I have, however, made the messages clearer.
78    
79    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
80        than the number used in the conditional) now cause a compile-time error.
81        This is actually not compatible with Perl, which accepts such patterns, but
82        treats the conditional as always being FALSE (as PCRE used to), but it
83        seems to me that giving a diagnostic is better.
84    
85    8.  Change "alphameric" to the more common word "alphanumeric" in comments
86        and messages.
87    
88    9.  Fix two occurrences of "backslash" in comments that should have been
89        "backspace".
90    
91    10. Remove two redundant lines of code that can never be obeyed (their function
92        was moved elsewhere).
93    
94    11. The program that makes PCRE's Unicode character property table had a bug
95        which caused it to generate incorrect table entries for sequences of
96        characters that have the same character type, but are in different scripts.
97        It amalgamated them into a single range, with the script of the first of
98        them. In other words, some characters were in the wrong script. There were
99        thirteen such cases, affecting characters in the following ranges:
100    
101          U+002b0 - U+002c1
102          U+0060c - U+0060d
103          U+0061e - U+00612
104          U+0064b - U+0065e
105          U+0074d - U+0076d
106          U+01800 - U+01805
107          U+01d00 - U+01d77
108          U+01d9b - U+01dbf
109          U+0200b - U+0200f
110          U+030fc - U+030fe
111          U+03260 - U+0327f
112          U+0fb46 - U+0fbb1
113          U+10450 - U+1049d
114    
115    12. The -o option (show only the matching part of a line) for pcregrep was not
116        compatible with GNU grep in that, if there was more than one match in a
117        line, it showed only the first of them. It now behaves in the same way as
118        GNU grep.
119    
120    13. If the -o and -v options were combined for pcregrep, it printed a blank
121        line for every non-matching line. GNU grep prints nothing, and pcregrep now
122        does the same. The return code can be used to tell if there were any
123        non-matching lines.
124    
125    14. Added --file-offsets and --line-offsets to pcregrep.
126    
127    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
128        infinitely looping recursion. The bug was that positive lookaheads were not
129        being skipped when checking for a possible empty match (negative lookaheads
130        and both kinds of lookbehind were skipped).
131    
132    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
133        inclusion of <windows.h> to before rather than after the definition of
134        INVALID_FILE_ATTRIBUTES (patch from David Byron).
135    
136    17. Specifying a possessive quantifier with a specific limit for a Unicode
137        character property caused pcre_compile() to compile bad code, which led at
138        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
139        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
140        caused the error; without that there was no problem.
141    
142    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
143    
144    19. Added --enable-pcretest-libreadline.
145    
146    20. In pcrecpp.cc, the variable 'count' was incremented twice in
147        RE::GlobalReplace(). As a result, the number of replacements returned was
148        double what it should be. I removed one of the increments, but Craig sent a
149        later patch that removed the other one (the right fix) and added unit tests
150        that check the return values (which was not done before).
151    
152    21. Several CMake things:
153    
154        (1) Arranged that, when cmake is used on Unix, the libraries end up with
155            the names libpcre and libpcreposix, not just pcre and pcreposix.
156    
157        (2) The above change means that pcretest and pcregrep are now correctly
158            linked with the newly-built libraries, not previously installed ones.
159    
160        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
161    
162    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
163        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
164        UTF-8 newline character). The key issue is that the pattern starts .*;
165        this means that the match must be either at the beginning, or after a
166        newline. The bug was in the code for advancing after a failed match and
167        checking that the new position followed a newline. It was not taking
168        account of UTF-8 characters correctly.
169    
170    23. PCRE was behaving differently from Perl in the way it recognized POSIX
171        character classes. PCRE was not treating the sequence [:...:] as a
172        character class unless the ... were all letters. Perl, however, seems to
173        allow any characters between [: and :], though of course it rejects as
174        unknown any "names" that contain non-letters, because all the known class
175        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
176        for example, whereas PCRE did not - it did not recognize a POSIX character
177        class. This seemed a bit dangerous, so the code has been changed to be
178        closer to Perl. The behaviour is not identical to Perl, because PCRE will
179        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
180        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
181        Perl does, and where it didn't before.
182    
183    24. Rewrite so as to remove the single use of %n from pcregrep because in some
184        Windows environments %n is disabled by default.
185    
186    
187    Version 7.4 21-Sep-07
188    ---------------------
189    
190    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
191        means that a class such as [\s] counted as "explicit reference to CR or
192        LF". That isn't really right - the whole point of the change was to try to
193        help when there was an actual mention of one of the two characters. So now
194        the change happens only if \r or \n (or a literal CR or LF) character is
195        encountered.
196    
197    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
198        of both had grown to the point where there were only 3 bits left.
199        Fortunately, there was spare space in the data structure, and so I have
200        moved the internal flags into a new 16-bit field to free up more option
201        bits.
202    
203    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
204        but did not set the internal JCHANGED flag - either of these is enough to
205        control the way the "get" function works - but the PCRE_INFO_JCHANGED
206        facility is supposed to tell if (?J) was ever used, so now (?J) at the
207        start sets both bits.
208    
209    4.  Added options (at build time, compile time, exec time) to change \R from
210        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
211    
212    5.  doc/pcresyntax.html was missing from the distribution.
213    
214    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
215        compatibility, even though it is no longer used.
216    
217    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
218        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
219        windows.h file is present (where different names are used). [This was
220        reversed later after testing - see 16 below.]
221    
222    8.  Changed all #include <config.h> to #include "config.h". There were also
223        some further <pcre.h> cases that I changed to "pcre.h".
224    
225    9.  When pcregrep was used with the --colour option, it missed the line ending
226        sequence off the lines that it output.
227    
228    10. It was pointed out to me that arrays of string pointers cause lots of
229        relocations when a shared library is dynamically loaded. A technique of
230        using a single long string with a table of offsets can drastically reduce
231        these. I have refactored PCRE in four places to do this. The result is
232        dramatic:
233    
234          Originally:                          290
235          After changing UCP table:            187
236          After changing error message table:   43
237          After changing table of "verbs"       36
238          After changing table of Posix names   22
239    
240        Thanks to the folks working on Gregex for glib for this insight.
241    
242    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
243        unicode-properties was also set.
244    
245    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
246    
247    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
248        checked only for CRLF.
249    
250    14. Added casts to pcretest.c to avoid compiler warnings.
251    
252    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
253    
254    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
255        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
256        entirely. This removes changes made in 7 above.
257    
258    17. The CMake files have been updated, and there is now more information about
259        building with CMake in the NON-UNIX-USE document.
260    
261    
262    Version 7.3 28-Aug-07
263    ---------------------
264    
265     1. In the rejigging of the build system that eventually resulted in 7.1, the
266        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
267        brackets there is not right, since it causes compilers to look for an
268        installed pcre.h, not the version that is in the source that is being
269        compiled (which of course may be different). I have changed it back to:
270    
271          #include "pcre.h"
272    
273        I have a vague recollection that the change was concerned with compiling in
274        different directories, but in the new build system, that is taken care of
275        by the VPATH setting the Makefile.
276    
277     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
278        when the subject happened to end in the byte 0x85 (e.g. if the last
279        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
280        characters but of course it shouldn't be taken as a newline when it is part
281        of another character. The bug was that, for an unlimited repeat of . in
282        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
283        characters when looking for a newline.
284    
285     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
286    
287     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
288        in debug output.
289    
290     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
291        long printing in the pcrecpp unittest when running under MinGW.
292    
293     6. ESC_K was left out of the EBCDIC table.
294    
295     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
296        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
297        limit also applies to "virtual nesting" when a pattern is recursive, and in
298        this case 1000 isn't so big. I have been able to remove this limit at the
299        expense of backing off one optimization in certain circumstances. Normally,
300        when pcre_exec() would call its internal match() function recursively and
301        immediately return the result unconditionally, it uses a "tail recursion"
302        feature to save stack. However, when a subpattern that can match an empty
303        string has an unlimited repetition quantifier, it no longer makes this
304        optimization. That gives it a stack frame in which to save the data for
305        checking that an empty string has been matched. Previously this was taken
306        from the 1000-entry workspace that had been reserved. So now there is no
307        explicit limit, but more stack is used.
308    
309     8. Applied Daniel's patches to solve problems with the import/export magic
310        syntax that is required for Windows, and which was going wrong for the
311        pcreposix and pcrecpp parts of the library. These were overlooked when this
312        problem was solved for the main library.
313    
314     9. There were some crude static tests to avoid integer overflow when computing
315        the size of patterns that contain repeated groups with explicit upper
316        limits. As the maximum quantifier is 65535, the maximum group length was
317        set at 30,000 so that the product of these two numbers did not overflow a
318        32-bit integer. However, it turns out that people want to use groups that
319        are longer than 30,000 bytes (though not repeat them that many times).
320        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
321        made it possible to implement the integer overflow checks in a much more
322        dynamic way, which I have now done. The artificial limitation on group
323        length has been removed - we now have only the limit on the total length of
324        the compiled pattern, which depends on the LINK_SIZE setting.
325    
326    10. Fixed a bug in the documentation for get/copy named substring when
327        duplicate names are permitted. If none of the named substrings are set, the
328        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
329        empty string.
330    
331    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
332        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
333        because the ] is interpreted as the first data character and the
334        terminating ] is not found. PCRE has been made compatible with Perl in this
335        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
336        cause memory overwriting.
337    
338    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
339        string has been matched (to stop an infinite loop). It was not recognizing
340        a conditional subpattern that could match an empty string if that
341        subpattern was within another subpattern. For example, it looped when
342        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
343        condition was not nested. This bug has been fixed.
344    
345    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
346        past the start of the subject in the presence of bytes with the top bit
347        set, for example "\x8aBCD".
348    
349    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
350        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
351    
352    14. Optimized (?!) to (*FAIL).
353    
354    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
355        This restricts code points to be within the range 0 to 0x10FFFF, excluding
356        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
357        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
358        does: it's just the validity check that is more restrictive.
359    
360    16. Inserted checks for integer overflows during escape sequence (backslash)
361        processing, and also fixed erroneous offset values for syntax errors during
362        backslash processing.
363    
364    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
365        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
366    
367    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
368        caused an overrun.
369    
370    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
371        something other than just ASCII characters) inside a group that had an
372        unlimited repeat caused a loop at compile time (while checking to see
373        whether the group could match an empty string).
374    
375    20. Debugging a pattern containing \p or \P could cause a crash. For example,
376        [\P{Any}] did so. (Error in the code for printing property names.)
377    
378    21. An orphan \E inside a character class could cause a crash.
379    
380    22. A repeated capturing bracket such as (A)? could cause a wild memory
381        reference during compilation.
382    
383    23. There are several functions in pcre_compile() that scan along a compiled
384        expression for various reasons (e.g. to see if it's fixed length for look
385        behind). There were bugs in these functions when a repeated \p or \P was
386        present in the pattern. These operators have additional parameters compared
387        with \d, etc, and these were not being taken into account when moving along
388        the compiled data. Specifically:
389    
390        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
391            length.
392    
393        (b) An item such as \pL+ within a repeated group could cause crashes or
394            loops.
395    
396        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
397            "reference to non-existent subpattern" error.
398    
399        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
400    
401    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
402        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
403    
404    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
405    
406    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
407        character were causing crashes (broken optimization).
408    
409    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
410        \p or \P) caused a compile-time loop.
411    
412    28. More problems have arisen in unanchored patterns when CRLF is a valid line
413        break. For example, the unstudied pattern [\r\n]A does not match the string
414        "\r\nA" because change 7.0/46 below moves the current point on by two
415        characters after failing to match at the start. However, the pattern \nA
416        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
417        the same is true. There doesn't seem any very clean way out of this, but
418        what I have chosen to do makes the common cases work: PCRE now takes note
419        of whether there can be an explicit match for \r or \n anywhere in the
420        pattern, and if so, 7.0/46 no longer applies. As part of this change,
421        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
422        pattern has explicit CR or LF references.
423    
424    29. Added (*CR) etc for changing newline setting at start of pattern.
425    
426    
427    Version 7.2 19-Jun-07
428    ---------------------
429    
430     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
431        which is apparently normally available under Windows.
432    
433     2. Re-jig the pcregrep tests with different newline settings in an attempt
434        to make them independent of the local environment's newline setting.
435    
436     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
437    
438     4. Some of the "internals" tests were previously cut out when the link size
439        was not 2, because the output contained actual offsets. The recent new
440        "Z" feature of pcretest means that these can be cut out, making the tests
441        usable with all link sizes.
442    
443     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
444        stack recursion. This gives a massive performance boost under BSD, but just
445        a small improvement under Linux. However, it saves one field in the frame
446        in all cases.
447    
448     6. Added more features from the forthcoming Perl 5.10:
449    
450        (a) (?-n) (where n is a string of digits) is a relative subroutine or
451            recursion call. It refers to the nth most recently opened parentheses.
452    
453        (b) (?+n) is also a relative subroutine call; it refers to the nth next
454            to be opened parentheses.
455    
456        (c) Conditions that refer to capturing parentheses can be specified
457            relatively, for example, (?(-2)... or (?(+3)...
458    
459        (d) \K resets the start of the current match so that everything before
460            is not part of it.
461    
462        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
463    
464        (f) \g{name} is another synonym - part of Perl 5.10's unification of
465            reference syntax.
466    
467        (g) (?| introduces a group in which the numbering of parentheses in each
468            alternative starts with the same number.
469    
470        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
471    
472     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
473        PCRE_INFO_JCHANGED.
474    
475     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
476        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
477        for detecting groups that can match an empty string.
478    
479     9. A pattern with a very large number of alternatives (more than several
480        hundred) was running out of internal workspace during the pre-compile
481        phase, where pcre_compile() figures out how much memory will be needed. A
482        bit of new cunning has reduced the workspace needed for groups with
483        alternatives. The 1000-alternative test pattern now uses 12 bytes of
484        workspace instead of running out of the 4096 that are available.
485    
486    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
487    
488    11. Applied patch from Google to remove an optimization that didn't quite work.
489        The report of the bug said:
490    
491          pcrecpp::RE("a*").FullMatch("aaa") matches, while
492          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
493          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
494    
495    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
496        it matched the wrong number of bytes.
497    
498    
499    Version 7.1 24-Apr-07
500    ---------------------
501    
502     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
503        that is more "standard", making use of automake and other Autotools. There
504        is some re-arrangement of the files and adjustment of comments consequent
505        on this.
506    
507     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
508        for recursive directory scanning broke on some systems because the files
509        are not scanned in any specific order and on different systems the order
510        was different. A call to "sort" has been inserted into RunGrepTest for the
511        approprate test as a short-term fix. In the longer term there may be an
512        alternative.
513    
514     3. I had an email from Eric Raymond about problems translating some of PCRE's
515        man pages to HTML (despite the fact that I distribute HTML pages, some
516        people do their own conversions for various reasons). The problems
517        concerned the use of low-level troff macros .br and .in. I have therefore
518        removed all such uses from the man pages (some were redundant, some could
519        be replaced by .nf/.fi pairs). The 132html script that I use to generate
520        HTML has been updated to handle .nf/.fi and to complain if it encounters
521        .br or .in.
522    
523     4. Updated comments in configure.ac that get placed in config.h.in and also
524        arranged for config.h to be included in the distribution, with the name
525        config.h.generic, for the benefit of those who have to compile without
526        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
527    
528     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
529        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
530        makevp.bat for the current PCRE, using the additional files
531        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
532    
533     6. A Windows user reported a minor discrepancy with test 2, which turned out
534        to be caused by a trailing space on an input line that had got lost in his
535        copy. The trailing space was an accident, so I've just removed it.
536    
537     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
538        that is needed.
539    
540     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
541        as "const" (a) because they are and (b) because it helps the PHP
542        maintainers who have recently made a script to detect big data structures
543        in the php code that should be moved to the .rodata section. I remembered
544        to update Builducptable as well, so it won't revert if ucptable.h is ever
545        re-created.
546    
547     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
548        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
549        order to be able to cut out the UTF-8 tables in the latter when UTF-8
550        support is not required. This saves 1.5-2K of code, which is important in
551        some applications.
552    
553        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
554        so as not to refer to the tables, even though these functions will never be
555        called when UTF-8 support is disabled. Otherwise there are problems with a
556        shared library.
557    
558    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
559    
560        (a) It was defining its arguments as char * instead of void *.
561    
562        (b) It was assuming that all moves were upwards in memory; this was true
563            a long time ago when I wrote it, but is no longer the case.
564    
565        The emulated memove() is provided for those environments that have neither
566        memmove() nor bcopy(). I didn't think anyone used it these days, but that
567        is clearly not the case, as these two bugs were recently reported.
568    
569    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
570        and Detrail to create the HTML documentation, the .txt form of the man
571        pages, and it removes trailing spaces from listed files. It also creates
572        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
573        case, it wraps all the #defines with #ifndefs. This script should be run
574        before "make dist".
575    
576    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
577        with Unicode property support.
578    
579        (a) For a maximizing quantifier, if the two different cases of the
580            character were of different lengths in their UTF-8 codings (there are
581            some cases like this - I found 11), and the matching function had to
582            back up over a mixture of the two cases, it incorrectly assumed they
583            were both the same length.
584    
585        (b) When PCRE was configured to use the heap rather than the stack for
586            recursion during matching, it was not correctly preserving the data for
587            the other case of a UTF-8 character when checking ahead for a match
588            while processing a minimizing repeat. If the check also involved
589            matching a wide character, but failed, corruption could cause an
590            erroneous result when trying to check for a repeat of the original
591            character.
592    
593    13. Some tidying changes to the testing mechanism:
594    
595        (a) The RunTest script now detects the internal link size and whether there
596            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
597            values substituted by "configure". (The RunGrepTest script already did
598            this for UTF-8.) The configure.ac script no longer substitutes the
599            relevant variables.
600    
601        (b) The debugging options /B and /D in pcretest show the compiled bytecode
602            with length and offset values. This means that the output is different
603            for different internal link sizes. Test 2 is skipped for link sizes
604            other than 2 because of this, bypassing the problem. Unfortunately,
605            there was also a test in test 3 (the locale tests) that used /B and
606            failed for link sizes other than 2. Rather than cut the whole test out,
607            I have added a new /Z option to pcretest that replaces the length and
608            offset values with spaces. This is now used to make test 3 independent
609            of link size. (Test 2 will be tidied up later.)
610    
611    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
612        segmentation fault instead of returning the appropriate error message.
613    
614    15. In multiline mode when the newline sequence was set to "any", the pattern
615        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
616        This doesn't seem right; it now treats the CRLF combination as the line
617        ending, and so does not match in that case. It's only a pattern such as ^$
618        that would hit this one: something like ^ABC$ would have failed after \r
619        and then tried again after \r\n.
620    
621    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
622        in an attempt to make files that differ only in their line terminators
623        compare equal. This works on Linux.
624    
625    17. Under certain error circumstances pcregrep might try to free random memory
626        as it exited. This is now fixed, thanks to valgrind.
627    
628    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
629        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
630        was because its rules for how to advance for /g after matching an empty
631        string at the end of a line did not allow for this case. They now check for
632        it specially.
633    
634    20. pcretest is supposed to handle patterns and data of any length, by
635        extending its buffers when necessary. It was getting this wrong when the
636        buffer for a data line had to be extended.
637    
638    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
639        CRLF as a newline sequence.
640    
641    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
642        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
643        I have nevertheless tidied it up.
644    
645    23. Added some casts to kill warnings from HP-UX ia64 compiler.
646    
647    24. Added a man page for pcre-config.
648    
649    
650    Version 7.0 19-Dec-06
651    ---------------------
652    
653     1. Fixed a signed/unsigned compiler warning in pcre_compile.c, shown up by
654        moving to gcc 4.1.1.
655    
656     2. The -S option for pcretest uses setrlimit(); I had omitted to #include
657        sys/time.h, which is documented as needed for this function. It doesn't
658        seem to matter on Linux, but it showed up on some releases of OS X.
659    
660     3. It seems that there are systems where bytes whose values are greater than
661        127 match isprint() in the "C" locale. The "C" locale should be the
662        default when a C program starts up. In most systems, only ASCII printing
663        characters match isprint(). This difference caused the output from pcretest
664        to vary, making some of the tests fail. I have changed pcretest so that:
665    
666        (a) When it is outputting text in the compiled version of a pattern, bytes
667            other than 32-126 are always shown as hex escapes.
668    
669        (b) When it is outputting text that is a matched part of a subject string,
670            it does the same, unless a different locale has been set for the match
671            (using the /L modifier). In this case, it uses isprint() to decide.
672    
673     4. Fixed a major bug that caused incorrect computation of the amount of memory
674        required for a compiled pattern when options that changed within the
675        pattern affected the logic of the preliminary scan that determines the
676        length. The relevant options are -x, and -i in UTF-8 mode. The result was
677        that the computed length was too small. The symptoms of this bug were
678        either the PCRE error "internal error: code overflow" from pcre_compile(),
679        or a glibc crash with a message such as "pcretest: free(): invalid next
680        size (fast)". Examples of patterns that provoked this bug (shown in
681        pcretest format) are:
682    
683          /(?-x: )/x
684          /(?x)(?-x: \s*#\s*)/
685          /((?i)[\x{c0}])/8
686          /(?i:[\x{c0}])/8
687    
688        HOWEVER: Change 17 below makes this fix obsolete as the memory computation
689        is now done differently.
690    
691     5. Applied patches from Google to: (a) add a QuoteMeta function to the C++
692        wrapper classes; (b) implement a new function in the C++ scanner that is
693        more efficient than the old way of doing things because it avoids levels of
694        recursion in the regex matching; (c) add a paragraph to the documentation
695        for the FullMatch() function.
696    
697     6. The escape sequence \n was being treated as whatever was defined as
698        "newline". Not only was this contrary to the documentation, which states
699        that \n is character 10 (hex 0A), but it also went horribly wrong when
700        "newline" was defined as CRLF. This has been fixed.
701    
702     7. In pcre_dfa_exec.c the value of an unsigned integer (the variable called c)
703        was being set to -1 for the "end of line" case (supposedly a value that no
704        character can have). Though this value is never used (the check for end of
705        line is "zero bytes in current character"), it caused compiler complaints.
706        I've changed it to 0xffffffff.
707    
708     8. In pcre_version.c, the version string was being built by a sequence of
709        C macros that, in the event of PCRE_PRERELEASE being defined as an empty
710        string (as it is for production releases) called a macro with an empty
711        argument. The C standard says the result of this is undefined. The gcc
712        compiler treats it as an empty string (which was what was wanted) but it is
713        reported that Visual C gives an error. The source has been hacked around to
714        avoid this problem.
715    
716     9. On the advice of a Windows user, included <io.h> and <fcntl.h> in Windows
717        builds of pcretest, and changed the call to _setmode() to use _O_BINARY
718        instead of 0x8000. Made all the #ifdefs test both _WIN32 and WIN32 (not all
719        of them did).
720    
721    10. Originally, pcretest opened its input and output without "b"; then I was
722        told that "b" was needed in some environments, so it was added for release
723        5.0 to both the input and output. (It makes no difference on Unix-like
724        systems.) Later I was told that it is wrong for the input on Windows. I've
725        now abstracted the modes into two macros, to make it easier to fiddle with
726        them, and removed "b" from the input mode under Windows.
727    
728    11. Added pkgconfig support for the C++ wrapper library, libpcrecpp.
729    
730    12. Added -help and --help to pcretest as an official way of being reminded
731        of the options.
732    
733    13. Removed some redundant semicolons after macro calls in pcrecpparg.h.in
734        and pcrecpp.cc because they annoy compilers at high warning levels.
735    
736    14. A bit of tidying/refactoring in pcre_exec.c in the main bumpalong loop.
737    
738    15. Fixed an occurrence of == in configure.ac that should have been = (shell
739        scripts are not C programs :-) and which was not noticed because it works
740        on Linux.
741    
742    16. pcretest is supposed to handle any length of pattern and data line (as one
743        line or as a continued sequence of lines) by extending its input buffer if
744        necessary. This feature was broken for very long pattern lines, leading to
745        a string of junk being passed to pcre_compile() if the pattern was longer
746        than about 50K.
747    
748    17. I have done a major re-factoring of the way pcre_compile() computes the
749        amount of memory needed for a compiled pattern. Previously, there was code
750        that made a preliminary scan of the pattern in order to do this. That was
751        OK when PCRE was new, but as the facilities have expanded, it has become
752        harder and harder to keep it in step with the real compile phase, and there
753        have been a number of bugs (see for example, 4 above). I have now found a
754        cunning way of running the real compile function in a "fake" mode that
755        enables it to compute how much memory it would need, while actually only
756        ever using a few hundred bytes of working memory and without too many
757        tests of the mode. This should make future maintenance and development
758        easier. A side effect of this work is that the limit of 200 on the nesting
759        depth of parentheses has been removed (though this was never a serious
760        limitation, I suspect). However, there is a downside: pcre_compile() now
761        runs more slowly than before (30% or more, depending on the pattern). I
762        hope this isn't a big issue. There is no effect on runtime performance.
763    
764    18. Fixed a minor bug in pcretest: if a pattern line was not terminated by a
765        newline (only possible for the last line of a file) and it was a
766        pattern that set a locale (followed by /Lsomething), pcretest crashed.
767    
768    19. Added additional timing features to pcretest. (1) The -tm option now times
769        matching only, not compiling. (2) Both -t and -tm can be followed, as a
770        separate command line item, by a number that specifies the number of
771        repeats to use when timing. The default is 50000; this gives better
772        precision, but takes uncomfortably long for very large patterns.
773    
774    20. Extended pcre_study() to be more clever in cases where a branch of a
775        subpattern has no definite first character. For example, (a*|b*)[cd] would
776        previously give no result from pcre_study(). Now it recognizes that the
777        first character must be a, b, c, or d.
778    
779    21. There was an incorrect error "recursive call could loop indefinitely" if
780        a subpattern (or the entire pattern) that was being tested for matching an
781        empty string contained only one non-empty item after a nested subpattern.
782        For example, the pattern (?>\x{100}*)\d(?R) provoked this error
783        incorrectly, because the \d was being skipped in the check.
784    
785    22. The pcretest program now has a new pattern option /B and a command line
786        option -b, which is equivalent to adding /B to every pattern. This causes
787        it to show the compiled bytecode, without the additional information that
788        -d shows. The effect of -d is now the same as -b with -i (and similarly, /D
789        is the same as /B/I).
790    
791    23. A new optimization is now able automatically to treat some sequences such
792        as a*b as a*+b. More specifically, if something simple (such as a character
793        or a simple class like \d) has an unlimited quantifier, and is followed by
794        something that cannot possibly match the quantified thing, the quantifier
795        is automatically "possessified".
796    
797    24. A recursive reference to a subpattern whose number was greater than 39
798        went wrong under certain circumstances in UTF-8 mode. This bug could also
799        have affected the operation of pcre_study().
800    
801    25. Realized that a little bit of performance could be had by replacing
802        (c & 0xc0) == 0xc0 with c >= 0xc0 when processing UTF-8 characters.
803    
804    26. Timing data from pcretest is now shown to 4 decimal places instead of 3.
805    
806    27. Possessive quantifiers such as a++ were previously implemented by turning
807        them into atomic groups such as ($>a+). Now they have their own opcodes,
808        which improves performance. This includes the automatically created ones
809        from 23 above.
810    
811    28. A pattern such as (?=(\w+))\1: which simulates an atomic group using a
812        lookahead was broken if it was not anchored. PCRE was mistakenly expecting
813        the first matched character to be a colon. This applied both to named and
814        numbered groups.
815    
816    29. The ucpinternal.h header file was missing its idempotency #ifdef.
817    
818    30. I was sent a "project" file called libpcre.a.dev which I understand makes
819        building PCRE on Windows easier, so I have included it in the distribution.
820    
821    31. There is now a check in pcretest against a ridiculously large number being
822        returned by pcre_exec() or pcre_dfa_exec(). If this happens in a /g or /G
823        loop, the loop is abandoned.
824    
825    32. Forward references to subpatterns in conditions such as (?(2)...) where
826        subpattern 2 is defined later cause pcre_compile() to search forwards in
827        the pattern for the relevant set of parentheses. This search went wrong
828        when there were unescaped parentheses in a character class, parentheses
829        escaped with \Q...\E, or parentheses in a #-comment in /x mode.
830    
831    33. "Subroutine" calls and backreferences were previously restricted to
832        referencing subpatterns earlier in the regex. This restriction has now
833        been removed.
834    
835    34. Added a number of extra features that are going to be in Perl 5.10. On the
836        whole, these are just syntactic alternatives for features that PCRE had
837        previously implemented using the Python syntax or my own invention. The
838        other formats are all retained for compatibility.
839    
840        (a) Named groups can now be defined as (?<name>...) or (?'name'...) as well
841            as (?P<name>...). The new forms, as well as being in Perl 5.10, are
842            also .NET compatible.
843    
844        (b) A recursion or subroutine call to a named group can now be defined as
845            (?&name) as well as (?P>name).
846    
847        (c) A backreference to a named group can now be defined as \k<name> or
848            \k'name' as well as (?P=name). The new forms, as well as being in Perl
849            5.10, are also .NET compatible.
850    
851        (d) A conditional reference to a named group can now use the syntax
852            (?(<name>) or (?('name') as well as (?(name).
853    
854        (e) A "conditional group" of the form (?(DEFINE)...) can be used to define
855            groups (named and numbered) that are never evaluated inline, but can be
856            called as "subroutines" from elsewhere. In effect, the DEFINE condition
857            is always false. There may be only one alternative in such a group.
858    
859        (f) A test for recursion can be given as (?(R1).. or (?(R&name)... as well
860            as the simple (?(R). The condition is true only if the most recent
861            recursion is that of the given number or name. It does not search out
862            through the entire recursion stack.
863    
864        (g) The escape \gN or \g{N} has been added, where N is a positive or
865            negative number, specifying an absolute or relative reference.
866    
867    35. Tidied to get rid of some further signed/unsigned compiler warnings and
868        some "unreachable code" warnings.
869    
870    36. Updated the Unicode property tables to Unicode version 5.0.0. Amongst other
871        things, this adds five new scripts.
872    
873    37. Perl ignores orphaned \E escapes completely. PCRE now does the same.
874        There were also incompatibilities regarding the handling of \Q..\E inside
875        character classes, for example with patterns like [\Qa\E-\Qz\E] where the
876        hyphen was adjacent to \Q or \E. I hope I've cleared all this up now.
877    
878    38. Like Perl, PCRE detects when an indefinitely repeated parenthesized group
879        matches an empty string, and forcibly breaks the loop. There were bugs in
880        this code in non-simple cases. For a pattern such as  ^(a()*)*  matched
881        against  aaaa  the result was just "a" rather than "aaaa", for example. Two
882        separate and independent bugs (that affected different cases) have been
883        fixed.
884    
885    39. Refactored the code to abolish the use of different opcodes for small
886        capturing bracket numbers. This is a tidy that I avoided doing when I
887        removed the limit on the number of capturing brackets for 3.5 back in 2001.
888        The new approach is not only tidier, it makes it possible to reduce the
889        memory needed to fix the previous bug (38).
890    
891    40. Implemented PCRE_NEWLINE_ANY to recognize any of the Unicode newline
892        sequences (http://unicode.org/unicode/reports/tr18/) as "newline" when
893        processing dot, circumflex, or dollar metacharacters, or #-comments in /x
894        mode.
895    
896    41. Add \R to match any Unicode newline sequence, as suggested in the Unicode
897        report.
898    
899    42. Applied patch, originally from Ari Pollak, modified by Google, to allow
900        copy construction and assignment in the C++ wrapper.
901    
902    43. Updated pcregrep to support "--newline=any". In the process, I fixed a
903        couple of bugs that could have given wrong results in the "--newline=crlf"
904        case.
905    
906    44. Added a number of casts and did some reorganization of signed/unsigned int
907        variables following suggestions from Dair Grant. Also renamed the variable
908        "this" as "item" because it is a C++ keyword.
909    
910    45. Arranged for dftables to add
911    
912          #include "pcre_internal.h"
913    
914        to pcre_chartables.c because without it, gcc 4.x may remove the array
915        definition from the final binary if PCRE is built into a static library and
916        dead code stripping is activated.
917    
918    46. For an unanchored pattern, if a match attempt fails at the start of a
919        newline sequence, and the newline setting is CRLF or ANY, and the next two
920        characters are CRLF, advance by two characters instead of one.
921    
922    
923  Version 6.7 04-Jul-06  Version 6.7 04-Jul-06
924  ---------------------  ---------------------
925    

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