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

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