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revision 195 by ph10, Mon Jul 30 13:23:28 2007 UTC revision 285 by ph10, Wed Dec 12 17:03:50 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.3 05-Jul-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    
95    Version 7.4 21-Sep-07
96    ---------------------
97    
98    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
99        means that a class such as [\s] counted as "explicit reference to CR or
100        LF". That isn't really right - the whole point of the change was to try to
101        help when there was an actual mention of one of the two characters. So now
102        the change happens only if \r or \n (or a literal CR or LF) character is
103        encountered.
104    
105    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
106        of both had grown to the point where there were only 3 bits left.
107        Fortunately, there was spare space in the data structure, and so I have
108        moved the internal flags into a new 16-bit field to free up more option
109        bits.
110    
111    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
112        but did not set the internal JCHANGED flag - either of these is enough to
113        control the way the "get" function works - but the PCRE_INFO_JCHANGED
114        facility is supposed to tell if (?J) was ever used, so now (?J) at the
115        start sets both bits.
116    
117    4.  Added options (at build time, compile time, exec time) to change \R from
118        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
119    
120    5.  doc/pcresyntax.html was missing from the distribution.
121    
122    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
123        compatibility, even though it is no longer used.
124    
125    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
126        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
127        windows.h file is present (where different names are used). [This was
128        reversed later after testing - see 16 below.]
129    
130    8.  Changed all #include <config.h> to #include "config.h". There were also
131        some further <pcre.h> cases that I changed to "pcre.h".
132    
133    9.  When pcregrep was used with the --colour option, it missed the line ending
134        sequence off the lines that it output.
135    
136    10. It was pointed out to me that arrays of string pointers cause lots of
137        relocations when a shared library is dynamically loaded. A technique of
138        using a single long string with a table of offsets can drastically reduce
139        these. I have refactored PCRE in four places to do this. The result is
140        dramatic:
141    
142          Originally:                          290
143          After changing UCP table:            187
144          After changing error message table:   43
145          After changing table of "verbs"       36
146          After changing table of Posix names   22
147    
148        Thanks to the folks working on Gregex for glib for this insight.
149    
150    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
151        unicode-properties was also set.
152    
153    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
154    
155    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
156        checked only for CRLF.
157    
158    14. Added casts to pcretest.c to avoid compiler warnings.
159    
160    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
161    
162    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
163        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
164        entirely. This removes changes made in 7 above.
165    
166    17. The CMake files have been updated, and there is now more information about
167        building with CMake in the NON-UNIX-USE document.
168    
169    
170    Version 7.3 28-Aug-07
171  ---------------------  ---------------------
172    
173   1. In the rejigging of the build system that eventually resulted in 7.1, the   1. In the rejigging of the build system that eventually resulted in 7.1, the
# Line 9  Version 7.3 05-Jul-07 Line 175  Version 7.3 05-Jul-07
175      brackets there is not right, since it causes compilers to look for an      brackets there is not right, since it causes compilers to look for an
176      installed pcre.h, not the version that is in the source that is being      installed pcre.h, not the version that is in the source that is being
177      compiled (which of course may be different). I have changed it back to:      compiled (which of course may be different). I have changed it back to:
178    
179        #include "pcre.h"        #include "pcre.h"
180    
181      I have a vague recollection that the change was concerned with compiling in      I have a vague recollection that the change was concerned with compiling in
182      different directories, but in the new build system, that is taken care of      different directories, but in the new build system, that is taken care of
183      by the VPATH setting the Makefile.      by the VPATH setting the Makefile.
184    
185   2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed   2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
186      when the subject happened to end in the byte 0x85 (e.g. if the last      when the subject happened to end in the byte 0x85 (e.g. if the last
187      character was \x{1ec5}). *Character* 0x85 is one of the "any" newline      character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
# Line 23  Version 7.3 05-Jul-07 Line 189  Version 7.3 05-Jul-07
189      of another character. The bug was that, for an unlimited repeat of . in      of another character. The bug was that, for an unlimited repeat of . in
190      not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by      not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
191      characters when looking for a newline.      characters when looking for a newline.
   
  3. A small performance improvement in the DOTALL UTF-8 mode .* case.  
   
  4. Debugging: adjusted the names of opcodes for different kinds of parentheses  
     in debug output.  
   
  5. Arrange to use "%I64d" instead of "%lld" for long printing in the pcrecpp  
     unittest when running under MinGW.  
   
  6. ESC_K was left out of the EBCDIC table.  
192    
193     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
194    
195     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
196        in debug output.
197    
198     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
199        long printing in the pcrecpp unittest when running under MinGW.
200    
201     6. ESC_K was left out of the EBCDIC table.
202    
203     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
204        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
205        limit also applies to "virtual nesting" when a pattern is recursive, and in
206        this case 1000 isn't so big. I have been able to remove this limit at the
207        expense of backing off one optimization in certain circumstances. Normally,
208        when pcre_exec() would call its internal match() function recursively and
209        immediately return the result unconditionally, it uses a "tail recursion"
210        feature to save stack. However, when a subpattern that can match an empty
211        string has an unlimited repetition quantifier, it no longer makes this
212        optimization. That gives it a stack frame in which to save the data for
213        checking that an empty string has been matched. Previously this was taken
214        from the 1000-entry workspace that had been reserved. So now there is no
215        explicit limit, but more stack is used.
216    
217     8. Applied Daniel's patches to solve problems with the import/export magic
218        syntax that is required for Windows, and which was going wrong for the
219        pcreposix and pcrecpp parts of the library. These were overlooked when this
220        problem was solved for the main library.
221    
222     9. There were some crude static tests to avoid integer overflow when computing
223        the size of patterns that contain repeated groups with explicit upper
224        limits. As the maximum quantifier is 65535, the maximum group length was
225        set at 30,000 so that the product of these two numbers did not overflow a
226        32-bit integer. However, it turns out that people want to use groups that
227        are longer than 30,000 bytes (though not repeat them that many times).
228        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
229        made it possible to implement the integer overflow checks in a much more
230        dynamic way, which I have now done. The artificial limitation on group
231        length has been removed - we now have only the limit on the total length of
232        the compiled pattern, which depends on the LINK_SIZE setting.
233    
234    10. Fixed a bug in the documentation for get/copy named substring when
235        duplicate names are permitted. If none of the named substrings are set, the
236        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
237        empty string.
238    
239    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
240        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
241        because the ] is interpreted as the first data character and the
242        terminating ] is not found. PCRE has been made compatible with Perl in this
243        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
244        cause memory overwriting.
245    
246    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
247        string has been matched (to stop an infinite loop). It was not recognizing
248        a conditional subpattern that could match an empty string if that
249        subpattern was within another subpattern. For example, it looped when
250        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
251        condition was not nested. This bug has been fixed.
252    
253    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
254        past the start of the subject in the presence of bytes with the top bit
255        set, for example "\x8aBCD".
256    
257    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
258        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
259    
260    14. Optimized (?!) to (*FAIL).
261    
262    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
263        This restricts code points to be within the range 0 to 0x10FFFF, excluding
264        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
265        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
266        does: it's just the validity check that is more restrictive.
267    
268    16. Inserted checks for integer overflows during escape sequence (backslash)
269        processing, and also fixed erroneous offset values for syntax errors during
270        backslash processing.
271    
272    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
273        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
274    
275    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
276        caused an overrun.
277    
278    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
279        something other than just ASCII characters) inside a group that had an
280        unlimited repeat caused a loop at compile time (while checking to see
281        whether the group could match an empty string).
282    
283    20. Debugging a pattern containing \p or \P could cause a crash. For example,
284        [\P{Any}] did so. (Error in the code for printing property names.)
285    
286    21. An orphan \E inside a character class could cause a crash.
287    
288    22. A repeated capturing bracket such as (A)? could cause a wild memory
289        reference during compilation.
290    
291    23. There are several functions in pcre_compile() that scan along a compiled
292        expression for various reasons (e.g. to see if it's fixed length for look
293        behind). There were bugs in these functions when a repeated \p or \P was
294        present in the pattern. These operators have additional parameters compared
295        with \d, etc, and these were not being taken into account when moving along
296        the compiled data. Specifically:
297    
298        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
299            length.
300    
301        (b) An item such as \pL+ within a repeated group could cause crashes or
302            loops.
303    
304        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
305            "reference to non-existent subpattern" error.
306    
307        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
308    
309    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
310        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
311    
312    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
313    
314    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
315        character were causing crashes (broken optimization).
316    
317    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
318        \p or \P) caused a compile-time loop.
319    
320    28. More problems have arisen in unanchored patterns when CRLF is a valid line
321        break. For example, the unstudied pattern [\r\n]A does not match the string
322        "\r\nA" because change 7.0/46 below moves the current point on by two
323        characters after failing to match at the start. However, the pattern \nA
324        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
325        the same is true. There doesn't seem any very clean way out of this, but
326        what I have chosen to do makes the common cases work: PCRE now takes note
327        of whether there can be an explicit match for \r or \n anywhere in the
328        pattern, and if so, 7.0/46 no longer applies. As part of this change,
329        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
330        pattern has explicit CR or LF references.
331    
332    29. Added (*CR) etc for changing newline setting at start of pattern.
333    
334    
335  Version 7.2 19-Jun-07  Version 7.2 19-Jun-07

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