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revision 166 by ph10, Wed May 9 14:48:28 2007 UTC revision 307 by ph10, Sun Jan 20 20:36:45 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 01-May-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    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.
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 created a dll
27        under mingw. I added stuff to Makefile.am that cause it to include this
28        special target, without affecting anything else.
29    
30    
31    Version 7.5 10-Jan-08
32    ---------------------
33    
34    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
35        values in parens when parsing an RE using the C++ wrapper."
36    
37    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
38        Characters greater than 255 were excluded from the class instead of being
39        included.
40    
41    3.  The same bug as (2) above applied to negated POSIX classes such as
42        [:^space:].
43    
44    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
45        defined or documented. It seems to have been a typo for PCRE_STATIC, so
46        I have changed it.
47    
48    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
49        first named subpattern) and a construct such as (?&a) would reference the
50        first named subpattern whose name started with "a" (in other words, the
51        length check was missing). Both these problems are fixed. "Subpattern name
52        expected" is now given for (?&) (a zero-length name), and this patch also
53        makes it give the same error for \k'' (previously it complained that that
54        was a reference to a non-existent subpattern).
55    
56    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
57        this is right because (?- can be followed by option settings as well as by
58        digits. I have, however, made the messages clearer.
59    
60    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
61        than the number used in the conditional) now cause a compile-time error.
62        This is actually not compatible with Perl, which accepts such patterns, but
63        treats the conditional as always being FALSE (as PCRE used to), but it
64        seems to me that giving a diagnostic is better.
65    
66    8.  Change "alphameric" to the more common word "alphanumeric" in comments
67        and messages.
68    
69    9.  Fix two occurrences of "backslash" in comments that should have been
70        "backspace".
71    
72    10. Remove two redundant lines of code that can never be obeyed (their function
73        was moved elsewhere).
74    
75    11. The program that makes PCRE's Unicode character property table had a bug
76        which caused it to generate incorrect table entries for sequences of
77        characters that have the same character type, but are in different scripts.
78        It amalgamated them into a single range, with the script of the first of
79        them. In other words, some characters were in the wrong script. There were
80        thirteen such cases, affecting characters in the following ranges:
81    
82          U+002b0 - U+002c1
83          U+0060c - U+0060d
84          U+0061e - U+00612
85          U+0064b - U+0065e
86          U+0074d - U+0076d
87          U+01800 - U+01805
88          U+01d00 - U+01d77
89          U+01d9b - U+01dbf
90          U+0200b - U+0200f
91          U+030fc - U+030fe
92          U+03260 - U+0327f
93          U+0fb46 - U+0fbb1
94          U+10450 - U+1049d
95    
96    12. The -o option (show only the matching part of a line) for pcregrep was not
97        compatible with GNU grep in that, if there was more than one match in a
98        line, it showed only the first of them. It now behaves in the same way as
99        GNU grep.
100    
101    13. If the -o and -v options were combined for pcregrep, it printed a blank
102        line for every non-matching line. GNU grep prints nothing, and pcregrep now
103        does the same. The return code can be used to tell if there were any
104        non-matching lines.
105    
106    14. Added --file-offsets and --line-offsets to pcregrep.
107    
108    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
109        infinitely looping recursion. The bug was that positive lookaheads were not
110        being skipped when checking for a possible empty match (negative lookaheads
111        and both kinds of lookbehind were skipped).
112    
113    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
114        inclusion of <windows.h> to before rather than after the definition of
115        INVALID_FILE_ATTRIBUTES (patch from David Byron).
116    
117    17. Specifying a possessive quantifier with a specific limit for a Unicode
118        character property caused pcre_compile() to compile bad code, which led at
119        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
120        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
121        caused the error; without that there was no problem.
122    
123    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
124    
125    19. Added --enable-pcretest-libreadline.
126    
127    20. In pcrecpp.cc, the variable 'count' was incremented twice in
128        RE::GlobalReplace(). As a result, the number of replacements returned was
129        double what it should be. I removed one of the increments, but Craig sent a
130        later patch that removed the other one (the right fix) and added unit tests
131        that check the return values (which was not done before).
132    
133    21. Several CMake things:
134    
135        (1) Arranged that, when cmake is used on Unix, the libraries end up with
136            the names libpcre and libpcreposix, not just pcre and pcreposix.
137    
138        (2) The above change means that pcretest and pcregrep are now correctly
139            linked with the newly-built libraries, not previously installed ones.
140    
141        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
142    
143    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
144        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
145        UTF-8 newline character). The key issue is that the pattern starts .*;
146        this means that the match must be either at the beginning, or after a
147        newline. The bug was in the code for advancing after a failed match and
148        checking that the new position followed a newline. It was not taking
149        account of UTF-8 characters correctly.
150    
151    23. PCRE was behaving differently from Perl in the way it recognized POSIX
152        character classes. PCRE was not treating the sequence [:...:] as a
153        character class unless the ... were all letters. Perl, however, seems to
154        allow any characters between [: and :], though of course it rejects as
155        unknown any "names" that contain non-letters, because all the known class
156        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
157        for example, whereas PCRE did not - it did not recognize a POSIX character
158        class. This seemed a bit dangerous, so the code has been changed to be
159        closer to Perl. The behaviour is not identical to Perl, because PCRE will
160        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
161        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
162        Perl does, and where it didn't before.
163    
164    24. Rewrite so as to remove the single use of %n from pcregrep because in some
165        Windows environments %n is disabled by default.
166    
167    
168    Version 7.4 21-Sep-07
169    ---------------------
170    
171    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
172        means that a class such as [\s] counted as "explicit reference to CR or
173        LF". That isn't really right - the whole point of the change was to try to
174        help when there was an actual mention of one of the two characters. So now
175        the change happens only if \r or \n (or a literal CR or LF) character is
176        encountered.
177    
178    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
179        of both had grown to the point where there were only 3 bits left.
180        Fortunately, there was spare space in the data structure, and so I have
181        moved the internal flags into a new 16-bit field to free up more option
182        bits.
183    
184    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
185        but did not set the internal JCHANGED flag - either of these is enough to
186        control the way the "get" function works - but the PCRE_INFO_JCHANGED
187        facility is supposed to tell if (?J) was ever used, so now (?J) at the
188        start sets both bits.
189    
190    4.  Added options (at build time, compile time, exec time) to change \R from
191        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
192    
193    5.  doc/pcresyntax.html was missing from the distribution.
194    
195    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
196        compatibility, even though it is no longer used.
197    
198    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
199        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
200        windows.h file is present (where different names are used). [This was
201        reversed later after testing - see 16 below.]
202    
203    8.  Changed all #include <config.h> to #include "config.h". There were also
204        some further <pcre.h> cases that I changed to "pcre.h".
205    
206    9.  When pcregrep was used with the --colour option, it missed the line ending
207        sequence off the lines that it output.
208    
209    10. It was pointed out to me that arrays of string pointers cause lots of
210        relocations when a shared library is dynamically loaded. A technique of
211        using a single long string with a table of offsets can drastically reduce
212        these. I have refactored PCRE in four places to do this. The result is
213        dramatic:
214    
215          Originally:                          290
216          After changing UCP table:            187
217          After changing error message table:   43
218          After changing table of "verbs"       36
219          After changing table of Posix names   22
220    
221        Thanks to the folks working on Gregex for glib for this insight.
222    
223    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
224        unicode-properties was also set.
225    
226    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
227    
228    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
229        checked only for CRLF.
230    
231    14. Added casts to pcretest.c to avoid compiler warnings.
232    
233    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
234    
235    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
236        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
237        entirely. This removes changes made in 7 above.
238    
239    17. The CMake files have been updated, and there is now more information about
240        building with CMake in the NON-UNIX-USE document.
241    
242    
243    Version 7.3 28-Aug-07
244    ---------------------
245    
246     1. In the rejigging of the build system that eventually resulted in 7.1, the
247        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
248        brackets there is not right, since it causes compilers to look for an
249        installed pcre.h, not the version that is in the source that is being
250        compiled (which of course may be different). I have changed it back to:
251    
252          #include "pcre.h"
253    
254        I have a vague recollection that the change was concerned with compiling in
255        different directories, but in the new build system, that is taken care of
256        by the VPATH setting the Makefile.
257    
258     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
259        when the subject happened to end in the byte 0x85 (e.g. if the last
260        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
261        characters but of course it shouldn't be taken as a newline when it is part
262        of another character. The bug was that, for an unlimited repeat of . in
263        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
264        characters when looking for a newline.
265    
266     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
267    
268     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
269        in debug output.
270    
271     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
272        long printing in the pcrecpp unittest when running under MinGW.
273    
274     6. ESC_K was left out of the EBCDIC table.
275    
276     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
277        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
278        limit also applies to "virtual nesting" when a pattern is recursive, and in
279        this case 1000 isn't so big. I have been able to remove this limit at the
280        expense of backing off one optimization in certain circumstances. Normally,
281        when pcre_exec() would call its internal match() function recursively and
282        immediately return the result unconditionally, it uses a "tail recursion"
283        feature to save stack. However, when a subpattern that can match an empty
284        string has an unlimited repetition quantifier, it no longer makes this
285        optimization. That gives it a stack frame in which to save the data for
286        checking that an empty string has been matched. Previously this was taken
287        from the 1000-entry workspace that had been reserved. So now there is no
288        explicit limit, but more stack is used.
289    
290     8. Applied Daniel's patches to solve problems with the import/export magic
291        syntax that is required for Windows, and which was going wrong for the
292        pcreposix and pcrecpp parts of the library. These were overlooked when this
293        problem was solved for the main library.
294    
295     9. There were some crude static tests to avoid integer overflow when computing
296        the size of patterns that contain repeated groups with explicit upper
297        limits. As the maximum quantifier is 65535, the maximum group length was
298        set at 30,000 so that the product of these two numbers did not overflow a
299        32-bit integer. However, it turns out that people want to use groups that
300        are longer than 30,000 bytes (though not repeat them that many times).
301        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
302        made it possible to implement the integer overflow checks in a much more
303        dynamic way, which I have now done. The artificial limitation on group
304        length has been removed - we now have only the limit on the total length of
305        the compiled pattern, which depends on the LINK_SIZE setting.
306    
307    10. Fixed a bug in the documentation for get/copy named substring when
308        duplicate names are permitted. If none of the named substrings are set, the
309        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
310        empty string.
311    
312    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
313        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
314        because the ] is interpreted as the first data character and the
315        terminating ] is not found. PCRE has been made compatible with Perl in this
316        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
317        cause memory overwriting.
318    
319    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
320        string has been matched (to stop an infinite loop). It was not recognizing
321        a conditional subpattern that could match an empty string if that
322        subpattern was within another subpattern. For example, it looped when
323        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
324        condition was not nested. This bug has been fixed.
325    
326    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
327        past the start of the subject in the presence of bytes with the top bit
328        set, for example "\x8aBCD".
329    
330    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
331        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
332    
333    14. Optimized (?!) to (*FAIL).
334    
335    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
336        This restricts code points to be within the range 0 to 0x10FFFF, excluding
337        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
338        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
339        does: it's just the validity check that is more restrictive.
340    
341    16. Inserted checks for integer overflows during escape sequence (backslash)
342        processing, and also fixed erroneous offset values for syntax errors during
343        backslash processing.
344    
345    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
346        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
347    
348    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
349        caused an overrun.
350    
351    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
352        something other than just ASCII characters) inside a group that had an
353        unlimited repeat caused a loop at compile time (while checking to see
354        whether the group could match an empty string).
355    
356    20. Debugging a pattern containing \p or \P could cause a crash. For example,
357        [\P{Any}] did so. (Error in the code for printing property names.)
358    
359    21. An orphan \E inside a character class could cause a crash.
360    
361    22. A repeated capturing bracket such as (A)? could cause a wild memory
362        reference during compilation.
363    
364    23. There are several functions in pcre_compile() that scan along a compiled
365        expression for various reasons (e.g. to see if it's fixed length for look
366        behind). There were bugs in these functions when a repeated \p or \P was
367        present in the pattern. These operators have additional parameters compared
368        with \d, etc, and these were not being taken into account when moving along
369        the compiled data. Specifically:
370    
371        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
372            length.
373    
374        (b) An item such as \pL+ within a repeated group could cause crashes or
375            loops.
376    
377        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
378            "reference to non-existent subpattern" error.
379    
380        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
381    
382    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
383        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
384    
385    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
386    
387    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
388        character were causing crashes (broken optimization).
389    
390    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
391        \p or \P) caused a compile-time loop.
392    
393    28. More problems have arisen in unanchored patterns when CRLF is a valid line
394        break. For example, the unstudied pattern [\r\n]A does not match the string
395        "\r\nA" because change 7.0/46 below moves the current point on by two
396        characters after failing to match at the start. However, the pattern \nA
397        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
398        the same is true. There doesn't seem any very clean way out of this, but
399        what I have chosen to do makes the common cases work: PCRE now takes note
400        of whether there can be an explicit match for \r or \n anywhere in the
401        pattern, and if so, 7.0/46 no longer applies. As part of this change,
402        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
403        pattern has explicit CR or LF references.
404    
405    29. Added (*CR) etc for changing newline setting at start of pattern.
406    
407    
408    Version 7.2 19-Jun-07
409  ---------------------  ---------------------
410    
411   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
# Line 21  Version 7.2 01-May-07 Line 425  Version 7.2 01-May-07
425      stack recursion. This gives a massive performance boost under BSD, but just      stack recursion. This gives a massive performance boost under BSD, but just
426      a small improvement under Linux. However, it saves one field in the frame      a small improvement under Linux. However, it saves one field in the frame
427      in all cases.      in all cases.
428    
429   6. Added more features from the forthcoming Perl 5.10:   6. Added more features from the forthcoming Perl 5.10:
430    
431      (a) (?-n) (where n is a string of digits) is a relative subroutine or      (a) (?-n) (where n is a string of digits) is a relative subroutine or
432          recursion call. It refers to the nth most recently opened parentheses.          recursion call. It refers to the nth most recently opened parentheses.
433    
434      (b) (?+n) is also a relative subroutine call; it refers to the nth next      (b) (?+n) is also a relative subroutine call; it refers to the nth next
435          to be opened parentheses.          to be opened parentheses.
436    
437        (c) Conditions that refer to capturing parentheses can be specified
438            relatively, for example, (?(-2)... or (?(+3)...
439    
440        (d) \K resets the start of the current match so that everything before
441            is not part of it.
442    
443        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
444    
445        (f) \g{name} is another synonym - part of Perl 5.10's unification of
446            reference syntax.
447    
448        (g) (?| introduces a group in which the numbering of parentheses in each
449            alternative starts with the same number.
450    
451        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
452    
453     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
454        PCRE_INFO_JCHANGED.
455    
456     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
457        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
458        for detecting groups that can match an empty string.
459    
460     9. A pattern with a very large number of alternatives (more than several
461        hundred) was running out of internal workspace during the pre-compile
462        phase, where pcre_compile() figures out how much memory will be needed. A
463        bit of new cunning has reduced the workspace needed for groups with
464        alternatives. The 1000-alternative test pattern now uses 12 bytes of
465        workspace instead of running out of the 4096 that are available.
466    
467    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
468    
469    11. Applied patch from Google to remove an optimization that didn't quite work.
470        The report of the bug said:
471    
472          pcrecpp::RE("a*").FullMatch("aaa") matches, while
473          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
474          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
475    
476    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
477        it matched the wrong number of bytes.
478    
479    
480  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07

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