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revision 175 by ph10, Mon Jun 11 13:38:38 2007 UTC revision 286 by ph10, Mon Dec 17 14:46:11 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 05-June-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    
97    Version 7.4 21-Sep-07
98    ---------------------
99    
100    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
101        means that a class such as [\s] counted as "explicit reference to CR or
102        LF". That isn't really right - the whole point of the change was to try to
103        help when there was an actual mention of one of the two characters. So now
104        the change happens only if \r or \n (or a literal CR or LF) character is
105        encountered.
106    
107    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
108        of both had grown to the point where there were only 3 bits left.
109        Fortunately, there was spare space in the data structure, and so I have
110        moved the internal flags into a new 16-bit field to free up more option
111        bits.
112    
113    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
114        but did not set the internal JCHANGED flag - either of these is enough to
115        control the way the "get" function works - but the PCRE_INFO_JCHANGED
116        facility is supposed to tell if (?J) was ever used, so now (?J) at the
117        start sets both bits.
118    
119    4.  Added options (at build time, compile time, exec time) to change \R from
120        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
121    
122    5.  doc/pcresyntax.html was missing from the distribution.
123    
124    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
125        compatibility, even though it is no longer used.
126    
127    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
128        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
129        windows.h file is present (where different names are used). [This was
130        reversed later after testing - see 16 below.]
131    
132    8.  Changed all #include <config.h> to #include "config.h". There were also
133        some further <pcre.h> cases that I changed to "pcre.h".
134    
135    9.  When pcregrep was used with the --colour option, it missed the line ending
136        sequence off the lines that it output.
137    
138    10. It was pointed out to me that arrays of string pointers cause lots of
139        relocations when a shared library is dynamically loaded. A technique of
140        using a single long string with a table of offsets can drastically reduce
141        these. I have refactored PCRE in four places to do this. The result is
142        dramatic:
143    
144          Originally:                          290
145          After changing UCP table:            187
146          After changing error message table:   43
147          After changing table of "verbs"       36
148          After changing table of Posix names   22
149    
150        Thanks to the folks working on Gregex for glib for this insight.
151    
152    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
153        unicode-properties was also set.
154    
155    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
156    
157    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
158        checked only for CRLF.
159    
160    14. Added casts to pcretest.c to avoid compiler warnings.
161    
162    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
163    
164    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
165        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
166        entirely. This removes changes made in 7 above.
167    
168    17. The CMake files have been updated, and there is now more information about
169        building with CMake in the NON-UNIX-USE document.
170    
171    
172    Version 7.3 28-Aug-07
173    ---------------------
174    
175     1. In the rejigging of the build system that eventually resulted in 7.1, the
176        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
177        brackets there is not right, since it causes compilers to look for an
178        installed pcre.h, not the version that is in the source that is being
179        compiled (which of course may be different). I have changed it back to:
180    
181          #include "pcre.h"
182    
183        I have a vague recollection that the change was concerned with compiling in
184        different directories, but in the new build system, that is taken care of
185        by the VPATH setting the Makefile.
186    
187     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
188        when the subject happened to end in the byte 0x85 (e.g. if the last
189        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
190        characters but of course it shouldn't be taken as a newline when it is part
191        of another character. The bug was that, for an unlimited repeat of . in
192        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
193        characters when looking for a newline.
194    
195     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
196    
197     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
198        in debug output.
199    
200     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
201        long printing in the pcrecpp unittest when running under MinGW.
202    
203     6. ESC_K was left out of the EBCDIC table.
204    
205     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
206        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
207        limit also applies to "virtual nesting" when a pattern is recursive, and in
208        this case 1000 isn't so big. I have been able to remove this limit at the
209        expense of backing off one optimization in certain circumstances. Normally,
210        when pcre_exec() would call its internal match() function recursively and
211        immediately return the result unconditionally, it uses a "tail recursion"
212        feature to save stack. However, when a subpattern that can match an empty
213        string has an unlimited repetition quantifier, it no longer makes this
214        optimization. That gives it a stack frame in which to save the data for
215        checking that an empty string has been matched. Previously this was taken
216        from the 1000-entry workspace that had been reserved. So now there is no
217        explicit limit, but more stack is used.
218    
219     8. Applied Daniel's patches to solve problems with the import/export magic
220        syntax that is required for Windows, and which was going wrong for the
221        pcreposix and pcrecpp parts of the library. These were overlooked when this
222        problem was solved for the main library.
223    
224     9. There were some crude static tests to avoid integer overflow when computing
225        the size of patterns that contain repeated groups with explicit upper
226        limits. As the maximum quantifier is 65535, the maximum group length was
227        set at 30,000 so that the product of these two numbers did not overflow a
228        32-bit integer. However, it turns out that people want to use groups that
229        are longer than 30,000 bytes (though not repeat them that many times).
230        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
231        made it possible to implement the integer overflow checks in a much more
232        dynamic way, which I have now done. The artificial limitation on group
233        length has been removed - we now have only the limit on the total length of
234        the compiled pattern, which depends on the LINK_SIZE setting.
235    
236    10. Fixed a bug in the documentation for get/copy named substring when
237        duplicate names are permitted. If none of the named substrings are set, the
238        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
239        empty string.
240    
241    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
242        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
243        because the ] is interpreted as the first data character and the
244        terminating ] is not found. PCRE has been made compatible with Perl in this
245        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
246        cause memory overwriting.
247    
248    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
249        string has been matched (to stop an infinite loop). It was not recognizing
250        a conditional subpattern that could match an empty string if that
251        subpattern was within another subpattern. For example, it looped when
252        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
253        condition was not nested. This bug has been fixed.
254    
255    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
256        past the start of the subject in the presence of bytes with the top bit
257        set, for example "\x8aBCD".
258    
259    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
260        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
261    
262    14. Optimized (?!) to (*FAIL).
263    
264    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
265        This restricts code points to be within the range 0 to 0x10FFFF, excluding
266        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
267        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
268        does: it's just the validity check that is more restrictive.
269    
270    16. Inserted checks for integer overflows during escape sequence (backslash)
271        processing, and also fixed erroneous offset values for syntax errors during
272        backslash processing.
273    
274    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
275        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
276    
277    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
278        caused an overrun.
279    
280    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
281        something other than just ASCII characters) inside a group that had an
282        unlimited repeat caused a loop at compile time (while checking to see
283        whether the group could match an empty string).
284    
285    20. Debugging a pattern containing \p or \P could cause a crash. For example,
286        [\P{Any}] did so. (Error in the code for printing property names.)
287    
288    21. An orphan \E inside a character class could cause a crash.
289    
290    22. A repeated capturing bracket such as (A)? could cause a wild memory
291        reference during compilation.
292    
293    23. There are several functions in pcre_compile() that scan along a compiled
294        expression for various reasons (e.g. to see if it's fixed length for look
295        behind). There were bugs in these functions when a repeated \p or \P was
296        present in the pattern. These operators have additional parameters compared
297        with \d, etc, and these were not being taken into account when moving along
298        the compiled data. Specifically:
299    
300        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
301            length.
302    
303        (b) An item such as \pL+ within a repeated group could cause crashes or
304            loops.
305    
306        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
307            "reference to non-existent subpattern" error.
308    
309        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
310    
311    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
312        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
313    
314    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
315    
316    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
317        character were causing crashes (broken optimization).
318    
319    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
320        \p or \P) caused a compile-time loop.
321    
322    28. More problems have arisen in unanchored patterns when CRLF is a valid line
323        break. For example, the unstudied pattern [\r\n]A does not match the string
324        "\r\nA" because change 7.0/46 below moves the current point on by two
325        characters after failing to match at the start. However, the pattern \nA
326        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
327        the same is true. There doesn't seem any very clean way out of this, but
328        what I have chosen to do makes the common cases work: PCRE now takes note
329        of whether there can be an explicit match for \r or \n anywhere in the
330        pattern, and if so, 7.0/46 no longer applies. As part of this change,
331        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
332        pattern has explicit CR or LF references.
333    
334    29. Added (*CR) etc for changing newline setting at start of pattern.
335    
336    
337    Version 7.2 19-Jun-07
338  ---------------------  ---------------------
339    
340   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 40  Version 7.2 05-June-07 Line 373  Version 7.2 05-June-07
373    
374      (f) \g{name} is another synonym - part of Perl 5.10's unification of      (f) \g{name} is another synonym - part of Perl 5.10's unification of
375          reference syntax.          reference syntax.
376    
377      (g) (?| introduces a group in which the numbering of parentheses in each      (g) (?| introduces a group in which the numbering of parentheses in each
378          alternative starts with the same number.          alternative starts with the same number.
379    
380        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
381    
382   7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and   7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
383      PCRE_INFO_JCHANGED.      PCRE_INFO_JCHANGED.
# Line 58  Version 7.2 05-June-07 Line 393  Version 7.2 05-June-07
393      alternatives. The 1000-alternative test pattern now uses 12 bytes of      alternatives. The 1000-alternative test pattern now uses 12 bytes of
394      workspace instead of running out of the 4096 that are available.      workspace instead of running out of the 4096 that are available.
395    
396    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
397    
398    11. Applied patch from Google to remove an optimization that didn't quite work.
399        The report of the bug said:
400    
401          pcrecpp::RE("a*").FullMatch("aaa") matches, while
402          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
403          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
404    
405    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
406        it matched the wrong number of bytes.
407    
408    
409  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
410  ---------------------  ---------------------

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