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revision 151 by ph10, Tue Apr 17 15:07:29 2007 UTC revision 287 by ph10, Tue Dec 18 20:11:28 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    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    
99    Version 7.4 21-Sep-07
100    ---------------------
101    
102    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
103        means that a class such as [\s] counted as "explicit reference to CR or
104        LF". That isn't really right - the whole point of the change was to try to
105        help when there was an actual mention of one of the two characters. So now
106        the change happens only if \r or \n (or a literal CR or LF) character is
107        encountered.
108    
109    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
110        of both had grown to the point where there were only 3 bits left.
111        Fortunately, there was spare space in the data structure, and so I have
112        moved the internal flags into a new 16-bit field to free up more option
113        bits.
114    
115    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
116        but did not set the internal JCHANGED flag - either of these is enough to
117        control the way the "get" function works - but the PCRE_INFO_JCHANGED
118        facility is supposed to tell if (?J) was ever used, so now (?J) at the
119        start sets both bits.
120    
121    4.  Added options (at build time, compile time, exec time) to change \R from
122        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
123    
124    5.  doc/pcresyntax.html was missing from the distribution.
125    
126    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
127        compatibility, even though it is no longer used.
128    
129    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
130        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
131        windows.h file is present (where different names are used). [This was
132        reversed later after testing - see 16 below.]
133    
134    8.  Changed all #include <config.h> to #include "config.h". There were also
135        some further <pcre.h> cases that I changed to "pcre.h".
136    
137    9.  When pcregrep was used with the --colour option, it missed the line ending
138        sequence off the lines that it output.
139    
140    10. It was pointed out to me that arrays of string pointers cause lots of
141        relocations when a shared library is dynamically loaded. A technique of
142        using a single long string with a table of offsets can drastically reduce
143        these. I have refactored PCRE in four places to do this. The result is
144        dramatic:
145    
146          Originally:                          290
147          After changing UCP table:            187
148          After changing error message table:   43
149          After changing table of "verbs"       36
150          After changing table of Posix names   22
151    
152        Thanks to the folks working on Gregex for glib for this insight.
153    
154    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
155        unicode-properties was also set.
156    
157    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
158    
159    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
160        checked only for CRLF.
161    
162    14. Added casts to pcretest.c to avoid compiler warnings.
163    
164    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
165    
166    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
167        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
168        entirely. This removes changes made in 7 above.
169    
170    17. The CMake files have been updated, and there is now more information about
171        building with CMake in the NON-UNIX-USE document.
172    
173    
174    Version 7.3 28-Aug-07
175    ---------------------
176    
177     1. In the rejigging of the build system that eventually resulted in 7.1, the
178        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
179        brackets there is not right, since it causes compilers to look for an
180        installed pcre.h, not the version that is in the source that is being
181        compiled (which of course may be different). I have changed it back to:
182    
183          #include "pcre.h"
184    
185        I have a vague recollection that the change was concerned with compiling in
186        different directories, but in the new build system, that is taken care of
187        by the VPATH setting the Makefile.
188    
189     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
190        when the subject happened to end in the byte 0x85 (e.g. if the last
191        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
192        characters but of course it shouldn't be taken as a newline when it is part
193        of another character. The bug was that, for an unlimited repeat of . in
194        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
195        characters when looking for a newline.
196    
197     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
198    
199     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
200        in debug output.
201    
202     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
203        long printing in the pcrecpp unittest when running under MinGW.
204    
205     6. ESC_K was left out of the EBCDIC table.
206    
207     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
208        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
209        limit also applies to "virtual nesting" when a pattern is recursive, and in
210        this case 1000 isn't so big. I have been able to remove this limit at the
211        expense of backing off one optimization in certain circumstances. Normally,
212        when pcre_exec() would call its internal match() function recursively and
213        immediately return the result unconditionally, it uses a "tail recursion"
214        feature to save stack. However, when a subpattern that can match an empty
215        string has an unlimited repetition quantifier, it no longer makes this
216        optimization. That gives it a stack frame in which to save the data for
217        checking that an empty string has been matched. Previously this was taken
218        from the 1000-entry workspace that had been reserved. So now there is no
219        explicit limit, but more stack is used.
220    
221     8. Applied Daniel's patches to solve problems with the import/export magic
222        syntax that is required for Windows, and which was going wrong for the
223        pcreposix and pcrecpp parts of the library. These were overlooked when this
224        problem was solved for the main library.
225    
226     9. There were some crude static tests to avoid integer overflow when computing
227        the size of patterns that contain repeated groups with explicit upper
228        limits. As the maximum quantifier is 65535, the maximum group length was
229        set at 30,000 so that the product of these two numbers did not overflow a
230        32-bit integer. However, it turns out that people want to use groups that
231        are longer than 30,000 bytes (though not repeat them that many times).
232        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
233        made it possible to implement the integer overflow checks in a much more
234        dynamic way, which I have now done. The artificial limitation on group
235        length has been removed - we now have only the limit on the total length of
236        the compiled pattern, which depends on the LINK_SIZE setting.
237    
238    10. Fixed a bug in the documentation for get/copy named substring when
239        duplicate names are permitted. If none of the named substrings are set, the
240        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
241        empty string.
242    
243    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
244        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
245        because the ] is interpreted as the first data character and the
246        terminating ] is not found. PCRE has been made compatible with Perl in this
247        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
248        cause memory overwriting.
249    
250    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
251        string has been matched (to stop an infinite loop). It was not recognizing
252        a conditional subpattern that could match an empty string if that
253        subpattern was within another subpattern. For example, it looped when
254        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
255        condition was not nested. This bug has been fixed.
256    
257    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
258        past the start of the subject in the presence of bytes with the top bit
259        set, for example "\x8aBCD".
260    
261    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
262        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
263    
264    14. Optimized (?!) to (*FAIL).
265    
266    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
267        This restricts code points to be within the range 0 to 0x10FFFF, excluding
268        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
269        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
270        does: it's just the validity check that is more restrictive.
271    
272    16. Inserted checks for integer overflows during escape sequence (backslash)
273        processing, and also fixed erroneous offset values for syntax errors during
274        backslash processing.
275    
276    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
277        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
278    
279    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
280        caused an overrun.
281    
282    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
283        something other than just ASCII characters) inside a group that had an
284        unlimited repeat caused a loop at compile time (while checking to see
285        whether the group could match an empty string).
286    
287    20. Debugging a pattern containing \p or \P could cause a crash. For example,
288        [\P{Any}] did so. (Error in the code for printing property names.)
289    
290    21. An orphan \E inside a character class could cause a crash.
291    
292    22. A repeated capturing bracket such as (A)? could cause a wild memory
293        reference during compilation.
294    
295    23. There are several functions in pcre_compile() that scan along a compiled
296        expression for various reasons (e.g. to see if it's fixed length for look
297        behind). There were bugs in these functions when a repeated \p or \P was
298        present in the pattern. These operators have additional parameters compared
299        with \d, etc, and these were not being taken into account when moving along
300        the compiled data. Specifically:
301    
302        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
303            length.
304    
305        (b) An item such as \pL+ within a repeated group could cause crashes or
306            loops.
307    
308        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
309            "reference to non-existent subpattern" error.
310    
311        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
312    
313    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
314        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
315    
316    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
317    
318    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
319        character were causing crashes (broken optimization).
320    
321    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
322        \p or \P) caused a compile-time loop.
323    
324    28. More problems have arisen in unanchored patterns when CRLF is a valid line
325        break. For example, the unstudied pattern [\r\n]A does not match the string
326        "\r\nA" because change 7.0/46 below moves the current point on by two
327        characters after failing to match at the start. However, the pattern \nA
328        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
329        the same is true. There doesn't seem any very clean way out of this, but
330        what I have chosen to do makes the common cases work: PCRE now takes note
331        of whether there can be an explicit match for \r or \n anywhere in the
332        pattern, and if so, 7.0/46 no longer applies. As part of this change,
333        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
334        pattern has explicit CR or LF references.
335    
336    29. Added (*CR) etc for changing newline setting at start of pattern.
337    
338    
339    Version 7.2 19-Jun-07
340    ---------------------
341    
342     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
343        which is apparently normally available under Windows.
344    
345     2. Re-jig the pcregrep tests with different newline settings in an attempt
346        to make them independent of the local environment's newline setting.
347    
348     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
349    
350     4. Some of the "internals" tests were previously cut out when the link size
351        was not 2, because the output contained actual offsets. The recent new
352        "Z" feature of pcretest means that these can be cut out, making the tests
353        usable with all link sizes.
354    
355     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
356        stack recursion. This gives a massive performance boost under BSD, but just
357        a small improvement under Linux. However, it saves one field in the frame
358        in all cases.
359    
360     6. Added more features from the forthcoming Perl 5.10:
361    
362        (a) (?-n) (where n is a string of digits) is a relative subroutine or
363            recursion call. It refers to the nth most recently opened parentheses.
364    
365        (b) (?+n) is also a relative subroutine call; it refers to the nth next
366            to be opened parentheses.
367    
368        (c) Conditions that refer to capturing parentheses can be specified
369            relatively, for example, (?(-2)... or (?(+3)...
370    
371        (d) \K resets the start of the current match so that everything before
372            is not part of it.
373    
374        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
375    
376        (f) \g{name} is another synonym - part of Perl 5.10's unification of
377            reference syntax.
378    
379        (g) (?| introduces a group in which the numbering of parentheses in each
380            alternative starts with the same number.
381    
382        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
383    
384     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
385        PCRE_INFO_JCHANGED.
386    
387     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
388        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
389        for detecting groups that can match an empty string.
390    
391     9. A pattern with a very large number of alternatives (more than several
392        hundred) was running out of internal workspace during the pre-compile
393        phase, where pcre_compile() figures out how much memory will be needed. A
394        bit of new cunning has reduced the workspace needed for groups with
395        alternatives. The 1000-alternative test pattern now uses 12 bytes of
396        workspace instead of running out of the 4096 that are available.
397    
398    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
399    
400    11. Applied patch from Google to remove an optimization that didn't quite work.
401        The report of the bug said:
402    
403          pcrecpp::RE("a*").FullMatch("aaa") matches, while
404          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
405          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
406    
407    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
408        it matched the wrong number of bytes.
409    
410    
411    Version 7.1 24-Apr-07
412  ---------------------  ---------------------
413    
414   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 142  Version 7.1 12-Mar-07 Line 549  Version 7.1 12-Mar-07
549    
550  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
551      CRLF as a newline sequence.      CRLF as a newline sequence.
552    
553  22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut  22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
554      out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but      out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
555      I have nevertheless tidied it up.      I have nevertheless tidied it up.
556    
557  23. Added some casts to kill warnings from HP-UX ia64 compiler.  23. Added some casts to kill warnings from HP-UX ia64 compiler.
558    
559    24. Added a man page for pcre-config.
560    
561    
562  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06

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