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revision 151 by ph10, Tue Apr 17 15:07:29 2007 UTC revision 302 by ph10, Sun Jan 20 19:12:46 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 7.6 19-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    
15    Version 7.5 10-Jan-08
16    ---------------------
17    
18    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
19        values in parens when parsing an RE using the C++ wrapper."
20    
21    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
22        Characters greater than 255 were excluded from the class instead of being
23        included.
24    
25    3.  The same bug as (2) above applied to negated POSIX classes such as
26        [:^space:].
27    
28    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
29        defined or documented. It seems to have been a typo for PCRE_STATIC, so
30        I have changed it.
31    
32    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
33        first named subpattern) and a construct such as (?&a) would reference the
34        first named subpattern whose name started with "a" (in other words, the
35        length check was missing). Both these problems are fixed. "Subpattern name
36        expected" is now given for (?&) (a zero-length name), and this patch also
37        makes it give the same error for \k'' (previously it complained that that
38        was a reference to a non-existent subpattern).
39    
40    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
41        this is right because (?- can be followed by option settings as well as by
42        digits. I have, however, made the messages clearer.
43    
44    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
45        than the number used in the conditional) now cause a compile-time error.
46        This is actually not compatible with Perl, which accepts such patterns, but
47        treats the conditional as always being FALSE (as PCRE used to), but it
48        seems to me that giving a diagnostic is better.
49    
50    8.  Change "alphameric" to the more common word "alphanumeric" in comments
51        and messages.
52    
53    9.  Fix two occurrences of "backslash" in comments that should have been
54        "backspace".
55    
56    10. Remove two redundant lines of code that can never be obeyed (their function
57        was moved elsewhere).
58    
59    11. The program that makes PCRE's Unicode character property table had a bug
60        which caused it to generate incorrect table entries for sequences of
61        characters that have the same character type, but are in different scripts.
62        It amalgamated them into a single range, with the script of the first of
63        them. In other words, some characters were in the wrong script. There were
64        thirteen such cases, affecting characters in the following ranges:
65    
66          U+002b0 - U+002c1
67          U+0060c - U+0060d
68          U+0061e - U+00612
69          U+0064b - U+0065e
70          U+0074d - U+0076d
71          U+01800 - U+01805
72          U+01d00 - U+01d77
73          U+01d9b - U+01dbf
74          U+0200b - U+0200f
75          U+030fc - U+030fe
76          U+03260 - U+0327f
77          U+0fb46 - U+0fbb1
78          U+10450 - U+1049d
79    
80    12. The -o option (show only the matching part of a line) for pcregrep was not
81        compatible with GNU grep in that, if there was more than one match in a
82        line, it showed only the first of them. It now behaves in the same way as
83        GNU grep.
84    
85    13. If the -o and -v options were combined for pcregrep, it printed a blank
86        line for every non-matching line. GNU grep prints nothing, and pcregrep now
87        does the same. The return code can be used to tell if there were any
88        non-matching lines.
89    
90    14. Added --file-offsets and --line-offsets to pcregrep.
91    
92    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
93        infinitely looping recursion. The bug was that positive lookaheads were not
94        being skipped when checking for a possible empty match (negative lookaheads
95        and both kinds of lookbehind were skipped).
96    
97    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
98        inclusion of <windows.h> to before rather than after the definition of
99        INVALID_FILE_ATTRIBUTES (patch from David Byron).
100    
101    17. Specifying a possessive quantifier with a specific limit for a Unicode
102        character property caused pcre_compile() to compile bad code, which led at
103        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
104        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
105        caused the error; without that there was no problem.
106    
107    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
108    
109    19. Added --enable-pcretest-libreadline.
110    
111    20. In pcrecpp.cc, the variable 'count' was incremented twice in
112        RE::GlobalReplace(). As a result, the number of replacements returned was
113        double what it should be. I removed one of the increments, but Craig sent a
114        later patch that removed the other one (the right fix) and added unit tests
115        that check the return values (which was not done before).
116    
117    21. Several CMake things:
118    
119        (1) Arranged that, when cmake is used on Unix, the libraries end up with
120            the names libpcre and libpcreposix, not just pcre and pcreposix.
121    
122        (2) The above change means that pcretest and pcregrep are now correctly
123            linked with the newly-built libraries, not previously installed ones.
124    
125        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
126    
127    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
128        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
129        UTF-8 newline character). The key issue is that the pattern starts .*;
130        this means that the match must be either at the beginning, or after a
131        newline. The bug was in the code for advancing after a failed match and
132        checking that the new position followed a newline. It was not taking
133        account of UTF-8 characters correctly.
134    
135    23. PCRE was behaving differently from Perl in the way it recognized POSIX
136        character classes. PCRE was not treating the sequence [:...:] as a
137        character class unless the ... were all letters. Perl, however, seems to
138        allow any characters between [: and :], though of course it rejects as
139        unknown any "names" that contain non-letters, because all the known class
140        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
141        for example, whereas PCRE did not - it did not recognize a POSIX character
142        class. This seemed a bit dangerous, so the code has been changed to be
143        closer to Perl. The behaviour is not identical to Perl, because PCRE will
144        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
145        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
146        Perl does, and where it didn't before.
147    
148    24. Rewrite so as to remove the single use of %n from pcregrep because in some
149        Windows environments %n is disabled by default.
150    
151    
152    Version 7.4 21-Sep-07
153    ---------------------
154    
155    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
156        means that a class such as [\s] counted as "explicit reference to CR or
157        LF". That isn't really right - the whole point of the change was to try to
158        help when there was an actual mention of one of the two characters. So now
159        the change happens only if \r or \n (or a literal CR or LF) character is
160        encountered.
161    
162    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
163        of both had grown to the point where there were only 3 bits left.
164        Fortunately, there was spare space in the data structure, and so I have
165        moved the internal flags into a new 16-bit field to free up more option
166        bits.
167    
168    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
169        but did not set the internal JCHANGED flag - either of these is enough to
170        control the way the "get" function works - but the PCRE_INFO_JCHANGED
171        facility is supposed to tell if (?J) was ever used, so now (?J) at the
172        start sets both bits.
173    
174    4.  Added options (at build time, compile time, exec time) to change \R from
175        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
176    
177    5.  doc/pcresyntax.html was missing from the distribution.
178    
179    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
180        compatibility, even though it is no longer used.
181    
182    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
183        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
184        windows.h file is present (where different names are used). [This was
185        reversed later after testing - see 16 below.]
186    
187    8.  Changed all #include <config.h> to #include "config.h". There were also
188        some further <pcre.h> cases that I changed to "pcre.h".
189    
190    9.  When pcregrep was used with the --colour option, it missed the line ending
191        sequence off the lines that it output.
192    
193    10. It was pointed out to me that arrays of string pointers cause lots of
194        relocations when a shared library is dynamically loaded. A technique of
195        using a single long string with a table of offsets can drastically reduce
196        these. I have refactored PCRE in four places to do this. The result is
197        dramatic:
198    
199          Originally:                          290
200          After changing UCP table:            187
201          After changing error message table:   43
202          After changing table of "verbs"       36
203          After changing table of Posix names   22
204    
205        Thanks to the folks working on Gregex for glib for this insight.
206    
207    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
208        unicode-properties was also set.
209    
210    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
211    
212    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
213        checked only for CRLF.
214    
215    14. Added casts to pcretest.c to avoid compiler warnings.
216    
217    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
218    
219    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
220        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
221        entirely. This removes changes made in 7 above.
222    
223    17. The CMake files have been updated, and there is now more information about
224        building with CMake in the NON-UNIX-USE document.
225    
226    
227    Version 7.3 28-Aug-07
228    ---------------------
229    
230     1. In the rejigging of the build system that eventually resulted in 7.1, the
231        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
232        brackets there is not right, since it causes compilers to look for an
233        installed pcre.h, not the version that is in the source that is being
234        compiled (which of course may be different). I have changed it back to:
235    
236          #include "pcre.h"
237    
238        I have a vague recollection that the change was concerned with compiling in
239        different directories, but in the new build system, that is taken care of
240        by the VPATH setting the Makefile.
241    
242     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
243        when the subject happened to end in the byte 0x85 (e.g. if the last
244        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
245        characters but of course it shouldn't be taken as a newline when it is part
246        of another character. The bug was that, for an unlimited repeat of . in
247        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
248        characters when looking for a newline.
249    
250     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
251    
252     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
253        in debug output.
254    
255     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
256        long printing in the pcrecpp unittest when running under MinGW.
257    
258     6. ESC_K was left out of the EBCDIC table.
259    
260     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
261        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
262        limit also applies to "virtual nesting" when a pattern is recursive, and in
263        this case 1000 isn't so big. I have been able to remove this limit at the
264        expense of backing off one optimization in certain circumstances. Normally,
265        when pcre_exec() would call its internal match() function recursively and
266        immediately return the result unconditionally, it uses a "tail recursion"
267        feature to save stack. However, when a subpattern that can match an empty
268        string has an unlimited repetition quantifier, it no longer makes this
269        optimization. That gives it a stack frame in which to save the data for
270        checking that an empty string has been matched. Previously this was taken
271        from the 1000-entry workspace that had been reserved. So now there is no
272        explicit limit, but more stack is used.
273    
274     8. Applied Daniel's patches to solve problems with the import/export magic
275        syntax that is required for Windows, and which was going wrong for the
276        pcreposix and pcrecpp parts of the library. These were overlooked when this
277        problem was solved for the main library.
278    
279     9. There were some crude static tests to avoid integer overflow when computing
280        the size of patterns that contain repeated groups with explicit upper
281        limits. As the maximum quantifier is 65535, the maximum group length was
282        set at 30,000 so that the product of these two numbers did not overflow a
283        32-bit integer. However, it turns out that people want to use groups that
284        are longer than 30,000 bytes (though not repeat them that many times).
285        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
286        made it possible to implement the integer overflow checks in a much more
287        dynamic way, which I have now done. The artificial limitation on group
288        length has been removed - we now have only the limit on the total length of
289        the compiled pattern, which depends on the LINK_SIZE setting.
290    
291    10. Fixed a bug in the documentation for get/copy named substring when
292        duplicate names are permitted. If none of the named substrings are set, the
293        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
294        empty string.
295    
296    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
297        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
298        because the ] is interpreted as the first data character and the
299        terminating ] is not found. PCRE has been made compatible with Perl in this
300        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
301        cause memory overwriting.
302    
303    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
304        string has been matched (to stop an infinite loop). It was not recognizing
305        a conditional subpattern that could match an empty string if that
306        subpattern was within another subpattern. For example, it looped when
307        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
308        condition was not nested. This bug has been fixed.
309    
310    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
311        past the start of the subject in the presence of bytes with the top bit
312        set, for example "\x8aBCD".
313    
314    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
315        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
316    
317    14. Optimized (?!) to (*FAIL).
318    
319    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
320        This restricts code points to be within the range 0 to 0x10FFFF, excluding
321        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
322        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
323        does: it's just the validity check that is more restrictive.
324    
325    16. Inserted checks for integer overflows during escape sequence (backslash)
326        processing, and also fixed erroneous offset values for syntax errors during
327        backslash processing.
328    
329    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
330        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
331    
332    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
333        caused an overrun.
334    
335    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
336        something other than just ASCII characters) inside a group that had an
337        unlimited repeat caused a loop at compile time (while checking to see
338        whether the group could match an empty string).
339    
340    20. Debugging a pattern containing \p or \P could cause a crash. For example,
341        [\P{Any}] did so. (Error in the code for printing property names.)
342    
343    21. An orphan \E inside a character class could cause a crash.
344    
345    22. A repeated capturing bracket such as (A)? could cause a wild memory
346        reference during compilation.
347    
348    23. There are several functions in pcre_compile() that scan along a compiled
349        expression for various reasons (e.g. to see if it's fixed length for look
350        behind). There were bugs in these functions when a repeated \p or \P was
351        present in the pattern. These operators have additional parameters compared
352        with \d, etc, and these were not being taken into account when moving along
353        the compiled data. Specifically:
354    
355        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
356            length.
357    
358        (b) An item such as \pL+ within a repeated group could cause crashes or
359            loops.
360    
361        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
362            "reference to non-existent subpattern" error.
363    
364        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
365    
366    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
367        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
368    
369    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
370    
371    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
372        character were causing crashes (broken optimization).
373    
374    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
375        \p or \P) caused a compile-time loop.
376    
377    28. More problems have arisen in unanchored patterns when CRLF is a valid line
378        break. For example, the unstudied pattern [\r\n]A does not match the string
379        "\r\nA" because change 7.0/46 below moves the current point on by two
380        characters after failing to match at the start. However, the pattern \nA
381        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
382        the same is true. There doesn't seem any very clean way out of this, but
383        what I have chosen to do makes the common cases work: PCRE now takes note
384        of whether there can be an explicit match for \r or \n anywhere in the
385        pattern, and if so, 7.0/46 no longer applies. As part of this change,
386        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
387        pattern has explicit CR or LF references.
388    
389    29. Added (*CR) etc for changing newline setting at start of pattern.
390    
391    
392    Version 7.2 19-Jun-07
393    ---------------------
394    
395     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
396        which is apparently normally available under Windows.
397    
398     2. Re-jig the pcregrep tests with different newline settings in an attempt
399        to make them independent of the local environment's newline setting.
400    
401     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
402    
403     4. Some of the "internals" tests were previously cut out when the link size
404        was not 2, because the output contained actual offsets. The recent new
405        "Z" feature of pcretest means that these can be cut out, making the tests
406        usable with all link sizes.
407    
408     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
409        stack recursion. This gives a massive performance boost under BSD, but just
410        a small improvement under Linux. However, it saves one field in the frame
411        in all cases.
412    
413     6. Added more features from the forthcoming Perl 5.10:
414    
415        (a) (?-n) (where n is a string of digits) is a relative subroutine or
416            recursion call. It refers to the nth most recently opened parentheses.
417    
418        (b) (?+n) is also a relative subroutine call; it refers to the nth next
419            to be opened parentheses.
420    
421        (c) Conditions that refer to capturing parentheses can be specified
422            relatively, for example, (?(-2)... or (?(+3)...
423    
424        (d) \K resets the start of the current match so that everything before
425            is not part of it.
426    
427        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
428    
429        (f) \g{name} is another synonym - part of Perl 5.10's unification of
430            reference syntax.
431    
432        (g) (?| introduces a group in which the numbering of parentheses in each
433            alternative starts with the same number.
434    
435        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
436    
437     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
438        PCRE_INFO_JCHANGED.
439    
440     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
441        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
442        for detecting groups that can match an empty string.
443    
444     9. A pattern with a very large number of alternatives (more than several
445        hundred) was running out of internal workspace during the pre-compile
446        phase, where pcre_compile() figures out how much memory will be needed. A
447        bit of new cunning has reduced the workspace needed for groups with
448        alternatives. The 1000-alternative test pattern now uses 12 bytes of
449        workspace instead of running out of the 4096 that are available.
450    
451    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
452    
453    11. Applied patch from Google to remove an optimization that didn't quite work.
454        The report of the bug said:
455    
456          pcrecpp::RE("a*").FullMatch("aaa") matches, while
457          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
458          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
459    
460    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
461        it matched the wrong number of bytes.
462    
463    
464    Version 7.1 24-Apr-07
465  ---------------------  ---------------------
466    
467   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 142  Version 7.1 12-Mar-07 Line 602  Version 7.1 12-Mar-07
602    
603  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
604      CRLF as a newline sequence.      CRLF as a newline sequence.
605    
606  22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut  22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
607      out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but      out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
608      I have nevertheless tidied it up.      I have nevertheless tidied it up.
609    
610  23. Added some casts to kill warnings from HP-UX ia64 compiler.  23. Added some casts to kill warnings from HP-UX ia64 compiler.
611    
612    24. Added a man page for pcre-config.
613    
614    
615  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06

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