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revision 150 by ph10, Tue Apr 17 08:22:40 2007 UTC revision 284 by ph10, Fri Dec 7 20:01:16 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-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    
89    Version 7.4 21-Sep-07
90    ---------------------
91    
92    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
93        means that a class such as [\s] counted as "explicit reference to CR or
94        LF". That isn't really right - the whole point of the change was to try to
95        help when there was an actual mention of one of the two characters. So now
96        the change happens only if \r or \n (or a literal CR or LF) character is
97        encountered.
98    
99    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
100        of both had grown to the point where there were only 3 bits left.
101        Fortunately, there was spare space in the data structure, and so I have
102        moved the internal flags into a new 16-bit field to free up more option
103        bits.
104    
105    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
106        but did not set the internal JCHANGED flag - either of these is enough to
107        control the way the "get" function works - but the PCRE_INFO_JCHANGED
108        facility is supposed to tell if (?J) was ever used, so now (?J) at the
109        start sets both bits.
110    
111    4.  Added options (at build time, compile time, exec time) to change \R from
112        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
113    
114    5.  doc/pcresyntax.html was missing from the distribution.
115    
116    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
117        compatibility, even though it is no longer used.
118    
119    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
120        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
121        windows.h file is present (where different names are used). [This was
122        reversed later after testing - see 16 below.]
123    
124    8.  Changed all #include <config.h> to #include "config.h". There were also
125        some further <pcre.h> cases that I changed to "pcre.h".
126    
127    9.  When pcregrep was used with the --colour option, it missed the line ending
128        sequence off the lines that it output.
129    
130    10. It was pointed out to me that arrays of string pointers cause lots of
131        relocations when a shared library is dynamically loaded. A technique of
132        using a single long string with a table of offsets can drastically reduce
133        these. I have refactored PCRE in four places to do this. The result is
134        dramatic:
135    
136          Originally:                          290
137          After changing UCP table:            187
138          After changing error message table:   43
139          After changing table of "verbs"       36
140          After changing table of Posix names   22
141    
142        Thanks to the folks working on Gregex for glib for this insight.
143    
144    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
145        unicode-properties was also set.
146    
147    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
148    
149    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
150        checked only for CRLF.
151    
152    14. Added casts to pcretest.c to avoid compiler warnings.
153    
154    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
155    
156    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
157        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
158        entirely. This removes changes made in 7 above.
159    
160    17. The CMake files have been updated, and there is now more information about
161        building with CMake in the NON-UNIX-USE document.
162    
163    
164    Version 7.3 28-Aug-07
165    ---------------------
166    
167     1. In the rejigging of the build system that eventually resulted in 7.1, the
168        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
169        brackets there is not right, since it causes compilers to look for an
170        installed pcre.h, not the version that is in the source that is being
171        compiled (which of course may be different). I have changed it back to:
172    
173          #include "pcre.h"
174    
175        I have a vague recollection that the change was concerned with compiling in
176        different directories, but in the new build system, that is taken care of
177        by the VPATH setting the Makefile.
178    
179     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
180        when the subject happened to end in the byte 0x85 (e.g. if the last
181        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
182        characters but of course it shouldn't be taken as a newline when it is part
183        of another character. The bug was that, for an unlimited repeat of . in
184        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
185        characters when looking for a newline.
186    
187     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
188    
189     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
190        in debug output.
191    
192     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
193        long printing in the pcrecpp unittest when running under MinGW.
194    
195     6. ESC_K was left out of the EBCDIC table.
196    
197     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
198        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
199        limit also applies to "virtual nesting" when a pattern is recursive, and in
200        this case 1000 isn't so big. I have been able to remove this limit at the
201        expense of backing off one optimization in certain circumstances. Normally,
202        when pcre_exec() would call its internal match() function recursively and
203        immediately return the result unconditionally, it uses a "tail recursion"
204        feature to save stack. However, when a subpattern that can match an empty
205        string has an unlimited repetition quantifier, it no longer makes this
206        optimization. That gives it a stack frame in which to save the data for
207        checking that an empty string has been matched. Previously this was taken
208        from the 1000-entry workspace that had been reserved. So now there is no
209        explicit limit, but more stack is used.
210    
211     8. Applied Daniel's patches to solve problems with the import/export magic
212        syntax that is required for Windows, and which was going wrong for the
213        pcreposix and pcrecpp parts of the library. These were overlooked when this
214        problem was solved for the main library.
215    
216     9. There were some crude static tests to avoid integer overflow when computing
217        the size of patterns that contain repeated groups with explicit upper
218        limits. As the maximum quantifier is 65535, the maximum group length was
219        set at 30,000 so that the product of these two numbers did not overflow a
220        32-bit integer. However, it turns out that people want to use groups that
221        are longer than 30,000 bytes (though not repeat them that many times).
222        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
223        made it possible to implement the integer overflow checks in a much more
224        dynamic way, which I have now done. The artificial limitation on group
225        length has been removed - we now have only the limit on the total length of
226        the compiled pattern, which depends on the LINK_SIZE setting.
227    
228    10. Fixed a bug in the documentation for get/copy named substring when
229        duplicate names are permitted. If none of the named substrings are set, the
230        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
231        empty string.
232    
233    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
234        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
235        because the ] is interpreted as the first data character and the
236        terminating ] is not found. PCRE has been made compatible with Perl in this
237        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
238        cause memory overwriting.
239    
240    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
241        string has been matched (to stop an infinite loop). It was not recognizing
242        a conditional subpattern that could match an empty string if that
243        subpattern was within another subpattern. For example, it looped when
244        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
245        condition was not nested. This bug has been fixed.
246    
247    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
248        past the start of the subject in the presence of bytes with the top bit
249        set, for example "\x8aBCD".
250    
251    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
252        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
253    
254    14. Optimized (?!) to (*FAIL).
255    
256    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
257        This restricts code points to be within the range 0 to 0x10FFFF, excluding
258        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
259        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
260        does: it's just the validity check that is more restrictive.
261    
262    16. Inserted checks for integer overflows during escape sequence (backslash)
263        processing, and also fixed erroneous offset values for syntax errors during
264        backslash processing.
265    
266    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
267        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
268    
269    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
270        caused an overrun.
271    
272    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
273        something other than just ASCII characters) inside a group that had an
274        unlimited repeat caused a loop at compile time (while checking to see
275        whether the group could match an empty string).
276    
277    20. Debugging a pattern containing \p or \P could cause a crash. For example,
278        [\P{Any}] did so. (Error in the code for printing property names.)
279    
280    21. An orphan \E inside a character class could cause a crash.
281    
282    22. A repeated capturing bracket such as (A)? could cause a wild memory
283        reference during compilation.
284    
285    23. There are several functions in pcre_compile() that scan along a compiled
286        expression for various reasons (e.g. to see if it's fixed length for look
287        behind). There were bugs in these functions when a repeated \p or \P was
288        present in the pattern. These operators have additional parameters compared
289        with \d, etc, and these were not being taken into account when moving along
290        the compiled data. Specifically:
291    
292        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
293            length.
294    
295        (b) An item such as \pL+ within a repeated group could cause crashes or
296            loops.
297    
298        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
299            "reference to non-existent subpattern" error.
300    
301        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
302    
303    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
304        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
305    
306    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
307    
308    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
309        character were causing crashes (broken optimization).
310    
311    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
312        \p or \P) caused a compile-time loop.
313    
314    28. More problems have arisen in unanchored patterns when CRLF is a valid line
315        break. For example, the unstudied pattern [\r\n]A does not match the string
316        "\r\nA" because change 7.0/46 below moves the current point on by two
317        characters after failing to match at the start. However, the pattern \nA
318        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
319        the same is true. There doesn't seem any very clean way out of this, but
320        what I have chosen to do makes the common cases work: PCRE now takes note
321        of whether there can be an explicit match for \r or \n anywhere in the
322        pattern, and if so, 7.0/46 no longer applies. As part of this change,
323        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
324        pattern has explicit CR or LF references.
325    
326    29. Added (*CR) etc for changing newline setting at start of pattern.
327    
328    
329    Version 7.2 19-Jun-07
330    ---------------------
331    
332     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
333        which is apparently normally available under Windows.
334    
335     2. Re-jig the pcregrep tests with different newline settings in an attempt
336        to make them independent of the local environment's newline setting.
337    
338     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
339    
340     4. Some of the "internals" tests were previously cut out when the link size
341        was not 2, because the output contained actual offsets. The recent new
342        "Z" feature of pcretest means that these can be cut out, making the tests
343        usable with all link sizes.
344    
345     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
346        stack recursion. This gives a massive performance boost under BSD, but just
347        a small improvement under Linux. However, it saves one field in the frame
348        in all cases.
349    
350     6. Added more features from the forthcoming Perl 5.10:
351    
352        (a) (?-n) (where n is a string of digits) is a relative subroutine or
353            recursion call. It refers to the nth most recently opened parentheses.
354    
355        (b) (?+n) is also a relative subroutine call; it refers to the nth next
356            to be opened parentheses.
357    
358        (c) Conditions that refer to capturing parentheses can be specified
359            relatively, for example, (?(-2)... or (?(+3)...
360    
361        (d) \K resets the start of the current match so that everything before
362            is not part of it.
363    
364        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
365    
366        (f) \g{name} is another synonym - part of Perl 5.10's unification of
367            reference syntax.
368    
369        (g) (?| introduces a group in which the numbering of parentheses in each
370            alternative starts with the same number.
371    
372        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
373    
374     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
375        PCRE_INFO_JCHANGED.
376    
377     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
378        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
379        for detecting groups that can match an empty string.
380    
381     9. A pattern with a very large number of alternatives (more than several
382        hundred) was running out of internal workspace during the pre-compile
383        phase, where pcre_compile() figures out how much memory will be needed. A
384        bit of new cunning has reduced the workspace needed for groups with
385        alternatives. The 1000-alternative test pattern now uses 12 bytes of
386        workspace instead of running out of the 4096 that are available.
387    
388    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
389    
390    11. Applied patch from Google to remove an optimization that didn't quite work.
391        The report of the bug said:
392    
393          pcrecpp::RE("a*").FullMatch("aaa") matches, while
394          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
395          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
396    
397    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
398        it matched the wrong number of bytes.
399    
400    
401    Version 7.1 24-Apr-07
402  ---------------------  ---------------------
403    
404   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
# Line 143  Version 7.1 12-Mar-07 Line 540  Version 7.1 12-Mar-07
540  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or  21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
541      CRLF as a newline sequence.      CRLF as a newline sequence.
542    
543    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
544        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
545        I have nevertheless tidied it up.
546    
547    23. Added some casts to kill warnings from HP-UX ia64 compiler.
548    
549    24. Added a man page for pcre-config.
550    
551    
552  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
553  ---------------------  ---------------------

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