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revision 184 by ph10, Tue Jun 19 13:26:46 2007 UTC revision 296 by ph10, Tue Jan 1 20:09:30 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.2 19-June-07  Version 7.5 31-Dec-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. Added --file-offsets and --line-offsets to pcregrep.
80    
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
85    
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
89    
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
95    
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
97    
98    19. Added --enable-pcretest-libreadline.
99    
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I have removed one of the increments.
103    
104    21. Several CMake things:
105    
106        (1) Arranged that, when cmake is used on Unix, the libraries end up with
107            the names libpcre and libpcreposix, not just pcre and pcreposix.
108    
109        (2) The above change means that pcretest and pcregrep are now correctly
110            linked with the newly-built libraries, not previously installed ones.
111    
112        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
113    
114    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
115        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
116        UTF-8 newline character). The key issue is that the pattern starts .*;
117        this means that the match must be either at the beginning, or after a
118        newline. The bug was in the code for advancing after a failed match and
119        checking that the new position followed a newline. It was not taking
120        account of UTF-8 characters correctly.
121    
122    23. PCRE was behaving differently from Perl in the way it recognized POSIX
123        character classes. PCRE was not treating the sequence [:...:] as a
124        character class unless the ... were all letters. Perl, however, seems to
125        allow any characters between [: and :], though of course it rejects as
126        unknown any "names" that contain non-letters, because all the known class
127        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
128        for example, whereas PCRE did not - it did not recognize a POSIX character
129        class. This seemed a bit dangerous, so the code has been changed to be
130        closer to Perl. The behaviour is not identical to Perl, because PCRE will
131        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
132        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
133        Perl does, and where it didn't before.
134    
135    24. Rewrite so as to remove the single use of %n from pcregrep because in some
136        Windows environments %n is disabled by default.
137    
138    
139    Version 7.4 21-Sep-07
140    ---------------------
141    
142    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
143        means that a class such as [\s] counted as "explicit reference to CR or
144        LF". That isn't really right - the whole point of the change was to try to
145        help when there was an actual mention of one of the two characters. So now
146        the change happens only if \r or \n (or a literal CR or LF) character is
147        encountered.
148    
149    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
150        of both had grown to the point where there were only 3 bits left.
151        Fortunately, there was spare space in the data structure, and so I have
152        moved the internal flags into a new 16-bit field to free up more option
153        bits.
154    
155    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
156        but did not set the internal JCHANGED flag - either of these is enough to
157        control the way the "get" function works - but the PCRE_INFO_JCHANGED
158        facility is supposed to tell if (?J) was ever used, so now (?J) at the
159        start sets both bits.
160    
161    4.  Added options (at build time, compile time, exec time) to change \R from
162        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
163    
164    5.  doc/pcresyntax.html was missing from the distribution.
165    
166    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
167        compatibility, even though it is no longer used.
168    
169    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
170        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
171        windows.h file is present (where different names are used). [This was
172        reversed later after testing - see 16 below.]
173    
174    8.  Changed all #include <config.h> to #include "config.h". There were also
175        some further <pcre.h> cases that I changed to "pcre.h".
176    
177    9.  When pcregrep was used with the --colour option, it missed the line ending
178        sequence off the lines that it output.
179    
180    10. It was pointed out to me that arrays of string pointers cause lots of
181        relocations when a shared library is dynamically loaded. A technique of
182        using a single long string with a table of offsets can drastically reduce
183        these. I have refactored PCRE in four places to do this. The result is
184        dramatic:
185    
186          Originally:                          290
187          After changing UCP table:            187
188          After changing error message table:   43
189          After changing table of "verbs"       36
190          After changing table of Posix names   22
191    
192        Thanks to the folks working on Gregex for glib for this insight.
193    
194    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
195        unicode-properties was also set.
196    
197    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
198    
199    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
200        checked only for CRLF.
201    
202    14. Added casts to pcretest.c to avoid compiler warnings.
203    
204    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
205    
206    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
207        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
208        entirely. This removes changes made in 7 above.
209    
210    17. The CMake files have been updated, and there is now more information about
211        building with CMake in the NON-UNIX-USE document.
212    
213    
214    Version 7.3 28-Aug-07
215    ---------------------
216    
217     1. In the rejigging of the build system that eventually resulted in 7.1, the
218        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
219        brackets there is not right, since it causes compilers to look for an
220        installed pcre.h, not the version that is in the source that is being
221        compiled (which of course may be different). I have changed it back to:
222    
223          #include "pcre.h"
224    
225        I have a vague recollection that the change was concerned with compiling in
226        different directories, but in the new build system, that is taken care of
227        by the VPATH setting the Makefile.
228    
229     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
230        when the subject happened to end in the byte 0x85 (e.g. if the last
231        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
232        characters but of course it shouldn't be taken as a newline when it is part
233        of another character. The bug was that, for an unlimited repeat of . in
234        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
235        characters when looking for a newline.
236    
237     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
238    
239     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
240        in debug output.
241    
242     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
243        long printing in the pcrecpp unittest when running under MinGW.
244    
245     6. ESC_K was left out of the EBCDIC table.
246    
247     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
248        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
249        limit also applies to "virtual nesting" when a pattern is recursive, and in
250        this case 1000 isn't so big. I have been able to remove this limit at the
251        expense of backing off one optimization in certain circumstances. Normally,
252        when pcre_exec() would call its internal match() function recursively and
253        immediately return the result unconditionally, it uses a "tail recursion"
254        feature to save stack. However, when a subpattern that can match an empty
255        string has an unlimited repetition quantifier, it no longer makes this
256        optimization. That gives it a stack frame in which to save the data for
257        checking that an empty string has been matched. Previously this was taken
258        from the 1000-entry workspace that had been reserved. So now there is no
259        explicit limit, but more stack is used.
260    
261     8. Applied Daniel's patches to solve problems with the import/export magic
262        syntax that is required for Windows, and which was going wrong for the
263        pcreposix and pcrecpp parts of the library. These were overlooked when this
264        problem was solved for the main library.
265    
266     9. There were some crude static tests to avoid integer overflow when computing
267        the size of patterns that contain repeated groups with explicit upper
268        limits. As the maximum quantifier is 65535, the maximum group length was
269        set at 30,000 so that the product of these two numbers did not overflow a
270        32-bit integer. However, it turns out that people want to use groups that
271        are longer than 30,000 bytes (though not repeat them that many times).
272        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
273        made it possible to implement the integer overflow checks in a much more
274        dynamic way, which I have now done. The artificial limitation on group
275        length has been removed - we now have only the limit on the total length of
276        the compiled pattern, which depends on the LINK_SIZE setting.
277    
278    10. Fixed a bug in the documentation for get/copy named substring when
279        duplicate names are permitted. If none of the named substrings are set, the
280        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
281        empty string.
282    
283    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
284        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
285        because the ] is interpreted as the first data character and the
286        terminating ] is not found. PCRE has been made compatible with Perl in this
287        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
288        cause memory overwriting.
289    
290    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
291        string has been matched (to stop an infinite loop). It was not recognizing
292        a conditional subpattern that could match an empty string if that
293        subpattern was within another subpattern. For example, it looped when
294        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
295        condition was not nested. This bug has been fixed.
296    
297    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
298        past the start of the subject in the presence of bytes with the top bit
299        set, for example "\x8aBCD".
300    
301    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
302        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
303    
304    14. Optimized (?!) to (*FAIL).
305    
306    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
307        This restricts code points to be within the range 0 to 0x10FFFF, excluding
308        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
309        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
310        does: it's just the validity check that is more restrictive.
311    
312    16. Inserted checks for integer overflows during escape sequence (backslash)
313        processing, and also fixed erroneous offset values for syntax errors during
314        backslash processing.
315    
316    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
317        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
318    
319    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
320        caused an overrun.
321    
322    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
323        something other than just ASCII characters) inside a group that had an
324        unlimited repeat caused a loop at compile time (while checking to see
325        whether the group could match an empty string).
326    
327    20. Debugging a pattern containing \p or \P could cause a crash. For example,
328        [\P{Any}] did so. (Error in the code for printing property names.)
329    
330    21. An orphan \E inside a character class could cause a crash.
331    
332    22. A repeated capturing bracket such as (A)? could cause a wild memory
333        reference during compilation.
334    
335    23. There are several functions in pcre_compile() that scan along a compiled
336        expression for various reasons (e.g. to see if it's fixed length for look
337        behind). There were bugs in these functions when a repeated \p or \P was
338        present in the pattern. These operators have additional parameters compared
339        with \d, etc, and these were not being taken into account when moving along
340        the compiled data. Specifically:
341    
342        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
343            length.
344    
345        (b) An item such as \pL+ within a repeated group could cause crashes or
346            loops.
347    
348        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
349            "reference to non-existent subpattern" error.
350    
351        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
352    
353    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
354        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
355    
356    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
357    
358    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
359        character were causing crashes (broken optimization).
360    
361    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
362        \p or \P) caused a compile-time loop.
363    
364    28. More problems have arisen in unanchored patterns when CRLF is a valid line
365        break. For example, the unstudied pattern [\r\n]A does not match the string
366        "\r\nA" because change 7.0/46 below moves the current point on by two
367        characters after failing to match at the start. However, the pattern \nA
368        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
369        the same is true. There doesn't seem any very clean way out of this, but
370        what I have chosen to do makes the common cases work: PCRE now takes note
371        of whether there can be an explicit match for \r or \n anywhere in the
372        pattern, and if so, 7.0/46 no longer applies. As part of this change,
373        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
374        pattern has explicit CR or LF references.
375    
376    29. Added (*CR) etc for changing newline setting at start of pattern.
377    
378    
379    Version 7.2 19-Jun-07
380  ---------------------  ---------------------
381    
382   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 68  Version 7.2 19-June-07 Line 443  Version 7.2 19-June-07
443        pcrecpp::RE("a*").FullMatch("aaa") matches, while        pcrecpp::RE("a*").FullMatch("aaa") matches, while
444        pcrecpp::RE("a*?").FullMatch("aaa") does not, and        pcrecpp::RE("a*?").FullMatch("aaa") does not, and
445        pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.        pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
446    
447  12. If \p or \P was used in non-UTF-8 mode on a character greater than 127  12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
448      it matched the wrong number of bytes.      it matched the wrong number of bytes.
449    
450    
451  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07

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