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revision 102 by ph10, Tue Mar 6 15:50:45 2007 UTC revision 226 by ph10, Tue Aug 21 11:46:08 2007 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 05-Mar-07  Version 7.3 20-Aug-07
5  ---------------------  ---------------------
6    
7   1. Applied Bob Rossi and Daniel G's patches to convert the build system to one   1. In the rejigging of the build system that eventually resulted in 7.1, the
8      that is more "standard", making use of automake and other autotools. There      line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
9        brackets there is not right, since it causes compilers to look for an
10        installed pcre.h, not the version that is in the source that is being
11        compiled (which of course may be different). I have changed it back to:
12    
13          #include "pcre.h"
14    
15        I have a vague recollection that the change was concerned with compiling in
16        different directories, but in the new build system, that is taken care of
17        by the VPATH setting the Makefile.
18    
19     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
20        when the subject happened to end in the byte 0x85 (e.g. if the last
21        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
22        characters but of course it shouldn't be taken as a newline when it is part
23        of another character. The bug was that, for an unlimited repeat of . in
24        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
25        characters when looking for a newline.
26    
27     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
28    
29     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
30        in debug output.
31    
32     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
33        long printing in the pcrecpp unittest when running under MinGW.
34    
35     6. ESC_K was left out of the EBCDIC table.
36    
37     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
38        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
39        limit also applies to "virtual nesting" when a pattern is recursive, and in
40        this case 1000 isn't so big. I have been able to remove this limit at the
41        expense of backing off one optimization in certain circumstances. Normally,
42        when pcre_exec() would call its internal match() function recursively and
43        immediately return the result unconditionally, it uses a "tail recursion"
44        feature to save stack. However, when a subpattern that can match an empty
45        string has an unlimited repetition quantifier, it no longer makes this
46        optimization. That gives it a stack frame in which to save the data for
47        checking that an empty string has been matched. Previously this was taken
48        from the 1000-entry workspace that had been reserved. So now there is no
49        explicit limit, but more stack is used.
50    
51     8. Applied Daniel's patches to solve problems with the import/export magic
52        syntax that is required for Windows, and which was going wrong for the
53        pcreposix and pcrecpp parts of the library. These were overlooked when this
54        problem was solved for the main library.
55    
56     9. There were some crude static tests to avoid integer overflow when computing
57        the size of patterns that contain repeated groups with explicit upper
58        limits. As the maximum quantifier is 65535, the maximum group length was
59        set at 30,000 so that the product of these two numbers did not overflow a
60        32-bit integer. However, it turns out that people want to use groups that
61        are longer than 30,000 bytes (though not repeat them that many times).
62        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
63        made it possible to implement the integer overflow checks in a much more
64        dynamic way, which I have now done. The artificial limitation on group
65        length has been removed - we now have only the limit on the total length of
66        the compiled pattern, which depends on the LINK_SIZE setting.
67    
68    10. Fixed a bug in the documentation for get/copy named substring when
69        duplicate names are permitted. If none of the named substrings are set, the
70        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
71        empty string.
72    
73    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
74        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
75        because the ] is interpreted as the first data character and the
76        terminating ] is not found. PCRE has been made compatible with Perl in this
77        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
78        cause memory overwriting.
79    
80    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
81        string has been matched (to stop an infinite loop). It was not recognizing
82        a conditional subpattern that could match an empty string if that
83        subpattern was within another subpattern. For example, it looped when
84        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
85        condition was not nested. This bug has been fixed.
86    
87    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
88        past the start of the subject in the presence of bytes with the top bit
89        set, for example "\x8aBCD".
90    
91    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
92        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
93    
94    14. Optimized (?!) to (*FAIL).
95    
96    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
97        This restricts code points to be within the range 0 to 0x10FFFF, excluding
98        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
99        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
100        does: it's just the validity check that is more restrictive.
101    
102    16. Inserted checks for integer overflows during escape sequence (backslash)
103        processing, and also fixed erroneous offset values for syntax errors during
104        backslash processing.
105    
106    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
108    
109    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110        caused an overrun.
111    
112    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113        something other than just ASCII characters) inside a group that had an
114        unlimited repeat caused a loop at compile time (while checking to see
115        whether the group could match an empty string).
116    
117    20. Debugging a pattern containing \p or \P could cause a crash. For example,
118        [\P{Any}] did so. (Error in the code for printing property names.)
119    
120    21. An orphan \E inside a character class could cause a crash.
121    
122    22. A repeated capturing bracket such as (A)? could cause a wild memory
123        reference during compilation.
124    
125    23. There are several functions in pcre_compile() that scan along a compiled
126        expression for various reasons (e.g. to see if it's fixed length for look
127        behind). There were bugs in these functions when a repeated \p or \P was
128        present in the pattern. These operators have additional parameters compared
129        with \d, etc, and these were not being taken into account when moving along
130        the compiled data. Specifically:
131    
132        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
133            length.
134    
135        (b) An item such as \pL+ within a repeated group could cause crashes or
136            loops.
137    
138        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
139            "reference to non-existent subpattern" error.
140    
141        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
142    
143    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
144        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
145    
146    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
147    
148    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
149        character were causing crashes (broken optimization).
150    
151    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
152        \p or \P) caused a compile-time loop.
153    
154    28. More problems have arisen in unanchored patterns when CRLF is a valid line
155        break. For example, the unstudied pattern [\r\n]A does not match the string
156        "\r\nA" because change 7.0/46 below moves the current point on by two
157        characters after failing to match at the start. However, the pattern \nA
158        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
159        the same is true. There doesn't seem any very clean way out of this, but
160        what I have chosen to do makes the common cases work: PCRE now takes note
161        of whether there can be an explicit match for \r or \n anywhere in the
162        pattern, and if so, 7.0/46 no longer applies. As part of this change,
163        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
164        pattern has explicit CR or LF references.
165    
166    
167    Version 7.2 19-Jun-07
168    ---------------------
169    
170     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
171        which is apparently normally available under Windows.
172    
173     2. Re-jig the pcregrep tests with different newline settings in an attempt
174        to make them independent of the local environment's newline setting.
175    
176     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
177    
178     4. Some of the "internals" tests were previously cut out when the link size
179        was not 2, because the output contained actual offsets. The recent new
180        "Z" feature of pcretest means that these can be cut out, making the tests
181        usable with all link sizes.
182    
183     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
184        stack recursion. This gives a massive performance boost under BSD, but just
185        a small improvement under Linux. However, it saves one field in the frame
186        in all cases.
187    
188     6. Added more features from the forthcoming Perl 5.10:
189    
190        (a) (?-n) (where n is a string of digits) is a relative subroutine or
191            recursion call. It refers to the nth most recently opened parentheses.
192    
193        (b) (?+n) is also a relative subroutine call; it refers to the nth next
194            to be opened parentheses.
195    
196        (c) Conditions that refer to capturing parentheses can be specified
197            relatively, for example, (?(-2)... or (?(+3)...
198    
199        (d) \K resets the start of the current match so that everything before
200            is not part of it.
201    
202        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
203    
204        (f) \g{name} is another synonym - part of Perl 5.10's unification of
205            reference syntax.
206    
207        (g) (?| introduces a group in which the numbering of parentheses in each
208            alternative starts with the same number.
209    
210        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
211    
212     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
213        PCRE_INFO_JCHANGED.
214    
215     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
216        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
217        for detecting groups that can match an empty string.
218    
219     9. A pattern with a very large number of alternatives (more than several
220        hundred) was running out of internal workspace during the pre-compile
221        phase, where pcre_compile() figures out how much memory will be needed. A
222        bit of new cunning has reduced the workspace needed for groups with
223        alternatives. The 1000-alternative test pattern now uses 12 bytes of
224        workspace instead of running out of the 4096 that are available.
225    
226    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
227    
228    11. Applied patch from Google to remove an optimization that didn't quite work.
229        The report of the bug said:
230    
231          pcrecpp::RE("a*").FullMatch("aaa") matches, while
232          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
233          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
234    
235    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
236        it matched the wrong number of bytes.
237    
238    
239    Version 7.1 24-Apr-07
240    ---------------------
241    
242     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
243        that is more "standard", making use of automake and other Autotools. There
244      is some re-arrangement of the files and adjustment of comments consequent      is some re-arrangement of the files and adjustment of comments consequent
245      on this.      on this.
246    
247   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
248      for recursive directory scanning broke on some systems because the files      for recursive directory scanning broke on some systems because the files
249      are not scanned in any specific order and on different systems the order      are not scanned in any specific order and on different systems the order
250      was different. A call to "sort" has been inserted into RunGrepTest for the      was different. A call to "sort" has been inserted into RunGrepTest for the
251      approprate test as a short-term fix. In the longer term there may be an      approprate test as a short-term fix. In the longer term there may be an
252      alternative.      alternative.
253    
254   3. I had an email from Eric Raymond about problems translating some of PCRE's   3. I had an email from Eric Raymond about problems translating some of PCRE's
255      man pages to HTML (despite the fact that I distribute HTML pages, some      man pages to HTML (despite the fact that I distribute HTML pages, some
256      people do their own conversions for various reasons). The problems      people do their own conversions for various reasons). The problems
257      concerned the use of low-level troff macros .br and .in. I have therefore      concerned the use of low-level troff macros .br and .in. I have therefore
258      removed all such uses from the man pages (some were redundant, some could      removed all such uses from the man pages (some were redundant, some could
259      be replaced by .nf/.fi pairs). The maintain/132html script that I use to      be replaced by .nf/.fi pairs). The 132html script that I use to generate
260      generate HTML has been updated to handle .nf/.fi and to complain if it      HTML has been updated to handle .nf/.fi and to complain if it encounters
261      encounters .br or .in.      .br or .in.
262    
263   4. Updated comments in configure.ac that get placed in config.h.in and also   4. Updated comments in configure.ac that get placed in config.h.in and also
264      arranged for config.h to be included in the distribution, for the benefit      arranged for config.h to be included in the distribution, with the name
265      of those who have to compile without Autotools (compare pcre.h).      config.h.generic, for the benefit of those who have to compile without
266        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
267   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan  
268      Weber: (1) pcre_internal.h was missing some function renames; (2) updated   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
269      makevp.bat for the current PCRE, using the additional files !compile.txt,      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
270      !linklib.txt, and pcregexp.pas.      makevp.bat for the current PCRE, using the additional files
271        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
272   6. A Windows user reported a minor discrepancy with test 2, which turned out  
273      to be caused by a trailing space on an input line that had got lost in his   6. A Windows user reported a minor discrepancy with test 2, which turned out
274        to be caused by a trailing space on an input line that had got lost in his
275      copy. The trailing space was an accident, so I've just removed it.      copy. The trailing space was an accident, so I've just removed it.
276    
277     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
278        that is needed.
279    
280     8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
281        as "const" (a) because they are and (b) because it helps the PHP
282        maintainers who have recently made a script to detect big data structures
283        in the php code that should be moved to the .rodata section. I remembered
284        to update Builducptable as well, so it won't revert if ucptable.h is ever
285        re-created.
286    
287     9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
288        pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
289        order to be able to cut out the UTF-8 tables in the latter when UTF-8
290        support is not required. This saves 1.5-2K of code, which is important in
291        some applications.
292    
293        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
294        so as not to refer to the tables, even though these functions will never be
295        called when UTF-8 support is disabled. Otherwise there are problems with a
296        shared library.
297    
298    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
299    
300        (a) It was defining its arguments as char * instead of void *.
301    
302        (b) It was assuming that all moves were upwards in memory; this was true
303            a long time ago when I wrote it, but is no longer the case.
304    
305        The emulated memove() is provided for those environments that have neither
306        memmove() nor bcopy(). I didn't think anyone used it these days, but that
307        is clearly not the case, as these two bugs were recently reported.
308    
309    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
310        and Detrail to create the HTML documentation, the .txt form of the man
311        pages, and it removes trailing spaces from listed files. It also creates
312        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
313        case, it wraps all the #defines with #ifndefs. This script should be run
314        before "make dist".
315    
316    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
317        with Unicode property support.
318    
319        (a) For a maximizing quantifier, if the two different cases of the
320            character were of different lengths in their UTF-8 codings (there are
321            some cases like this - I found 11), and the matching function had to
322            back up over a mixture of the two cases, it incorrectly assumed they
323            were both the same length.
324    
325        (b) When PCRE was configured to use the heap rather than the stack for
326            recursion during matching, it was not correctly preserving the data for
327            the other case of a UTF-8 character when checking ahead for a match
328            while processing a minimizing repeat. If the check also involved
329            matching a wide character, but failed, corruption could cause an
330            erroneous result when trying to check for a repeat of the original
331            character.
332    
333    13. Some tidying changes to the testing mechanism:
334    
335        (a) The RunTest script now detects the internal link size and whether there
336            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
337            values substituted by "configure". (The RunGrepTest script already did
338            this for UTF-8.) The configure.ac script no longer substitutes the
339            relevant variables.
340    
341        (b) The debugging options /B and /D in pcretest show the compiled bytecode
342            with length and offset values. This means that the output is different
343            for different internal link sizes. Test 2 is skipped for link sizes
344            other than 2 because of this, bypassing the problem. Unfortunately,
345            there was also a test in test 3 (the locale tests) that used /B and
346            failed for link sizes other than 2. Rather than cut the whole test out,
347            I have added a new /Z option to pcretest that replaces the length and
348            offset values with spaces. This is now used to make test 3 independent
349            of link size. (Test 2 will be tidied up later.)
350    
351    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
352        segmentation fault instead of returning the appropriate error message.
353    
354    15. In multiline mode when the newline sequence was set to "any", the pattern
355        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
356        This doesn't seem right; it now treats the CRLF combination as the line
357        ending, and so does not match in that case. It's only a pattern such as ^$
358        that would hit this one: something like ^ABC$ would have failed after \r
359        and then tried again after \r\n.
360    
361    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
362        in an attempt to make files that differ only in their line terminators
363        compare equal. This works on Linux.
364    
365    17. Under certain error circumstances pcregrep might try to free random memory
366        as it exited. This is now fixed, thanks to valgrind.
367    
368    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
369        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
370        was because its rules for how to advance for /g after matching an empty
371        string at the end of a line did not allow for this case. They now check for
372        it specially.
373    
374    20. pcretest is supposed to handle patterns and data of any length, by
375        extending its buffers when necessary. It was getting this wrong when the
376        buffer for a data line had to be extended.
377    
378    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
379        CRLF as a newline sequence.
380    
381    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
382        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
383        I have nevertheless tidied it up.
384    
385    23. Added some casts to kill warnings from HP-UX ia64 compiler.
386    
387    24. Added a man page for pcre-config.
388    
389    
390  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
391  ---------------------  ---------------------

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