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revision 107 by ph10, Wed Mar 7 11:02:28 2007 UTC revision 218 by ph10, Thu Aug 16 10:13:23 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 09-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      is some re-arrangement of the files and adjustment of comments consequent      brackets there is not right, since it causes compilers to look for an
10      on this.      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   2. Part of the patch fixed a problem with the pcregrep tests. The test of -r  16. Inserted checks for integer overflows during escape sequence (backslash)
103      for recursive directory scanning broke on some systems because the files      processing, and also fixed erroneous offset values for syntax errors during
104      are not scanned in any specific order and on different systems the order      backslash processing.
     was different. A call to "sort" has been inserted into RunGrepTest for the  
     approprate test as a short-term fix. In the longer term there may be an  
     alternative.  
105    
106   3. I had an email from Eric Raymond about problems translating some of PCRE's  17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
107      man pages to HTML (despite the fact that I distribute HTML pages, some      for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
     people do their own conversions for various reasons). The problems  
     concerned the use of low-level troff macros .br and .in. I have therefore  
     removed all such uses from the man pages (some were redundant, some could  
     be replaced by .nf/.fi pairs). The maintain/132html script that I use to  
     generate HTML has been updated to handle .nf/.fi and to complain if it  
     encounters .br or .in.  
108    
109   4. Updated comments in configure.ac that get placed in config.h.in and also  18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
110      arranged for config.h to be included in the distribution, for the benefit      caused an overrun.
     of those who have to compile without Autotools (compare pcre.h).  
111    
112   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan  19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
113      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      something other than just ASCII characters) inside a group that had an
114      makevp.bat for the current PCRE, using the additional files !compile.txt,      unlimited repeat caused a loop at compile time (while checking to see
115      !linklib.txt, and pcregexp.pas.      whether the group could match an empty string).
116    
117   6. A Windows user reported a minor discrepancy with test 2, which turned out  20. Debugging a pattern containing \p or \P could cause a crash. For example,
118      to be caused by a trailing space on an input line that had got lost in his      [\P{Any}] did so. (Error in the code for printing property names.)
     copy. The trailing space was an accident, so I've just removed it.  
119    
120   7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told  21. An orphan \E inside a character class could cause a crash.
121      that is needed.  
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    
142    Version 7.2 19-Jun-07
143    ---------------------
144    
145     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
146        which is apparently normally available under Windows.
147    
148     2. Re-jig the pcregrep tests with different newline settings in an attempt
149        to make them independent of the local environment's newline setting.
150    
151     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
152    
153     4. Some of the "internals" tests were previously cut out when the link size
154        was not 2, because the output contained actual offsets. The recent new
155        "Z" feature of pcretest means that these can be cut out, making the tests
156        usable with all link sizes.
157    
158     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
159        stack recursion. This gives a massive performance boost under BSD, but just
160        a small improvement under Linux. However, it saves one field in the frame
161        in all cases.
162    
163     6. Added more features from the forthcoming Perl 5.10:
164    
165        (a) (?-n) (where n is a string of digits) is a relative subroutine or
166            recursion call. It refers to the nth most recently opened parentheses.
167    
168        (b) (?+n) is also a relative subroutine call; it refers to the nth next
169            to be opened parentheses.
170    
171        (c) Conditions that refer to capturing parentheses can be specified
172            relatively, for example, (?(-2)... or (?(+3)...
173    
174        (d) \K resets the start of the current match so that everything before
175            is not part of it.
176    
177        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
178    
179        (f) \g{name} is another synonym - part of Perl 5.10's unification of
180            reference syntax.
181    
182        (g) (?| introduces a group in which the numbering of parentheses in each
183            alternative starts with the same number.
184    
185        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
186    
187     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
188        PCRE_INFO_JCHANGED.
189    
190     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
191        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
192        for detecting groups that can match an empty string.
193    
194     9. A pattern with a very large number of alternatives (more than several
195        hundred) was running out of internal workspace during the pre-compile
196        phase, where pcre_compile() figures out how much memory will be needed. A
197        bit of new cunning has reduced the workspace needed for groups with
198        alternatives. The 1000-alternative test pattern now uses 12 bytes of
199        workspace instead of running out of the 4096 that are available.
200    
201    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
202    
203    11. Applied patch from Google to remove an optimization that didn't quite work.
204        The report of the bug said:
205    
206          pcrecpp::RE("a*").FullMatch("aaa") matches, while
207          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
208          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
209    
210    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
211        it matched the wrong number of bytes.
212    
213    
214    Version 7.1 24-Apr-07
215    ---------------------
216    
217     1. Applied Bob Rossi and Daniel G's patches to convert the build system to one
218        that is more "standard", making use of automake and other Autotools. There
219        is some re-arrangement of the files and adjustment of comments consequent
220        on this.
221    
222     2. Part of the patch fixed a problem with the pcregrep tests. The test of -r
223        for recursive directory scanning broke on some systems because the files
224        are not scanned in any specific order and on different systems the order
225        was different. A call to "sort" has been inserted into RunGrepTest for the
226        approprate test as a short-term fix. In the longer term there may be an
227        alternative.
228    
229     3. I had an email from Eric Raymond about problems translating some of PCRE's
230        man pages to HTML (despite the fact that I distribute HTML pages, some
231        people do their own conversions for various reasons). The problems
232        concerned the use of low-level troff macros .br and .in. I have therefore
233        removed all such uses from the man pages (some were redundant, some could
234        be replaced by .nf/.fi pairs). The 132html script that I use to generate
235        HTML has been updated to handle .nf/.fi and to complain if it encounters
236        .br or .in.
237    
238     4. Updated comments in configure.ac that get placed in config.h.in and also
239        arranged for config.h to be included in the distribution, with the name
240        config.h.generic, for the benefit of those who have to compile without
241        Autotools (compare pcre.h, which is now distributed as pcre.h.generic).
242    
243     5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
244        Weber: (1) pcre_internal.h was missing some function renames; (2) updated
245        makevp.bat for the current PCRE, using the additional files
246        makevp_c.txt, makevp_l.txt, and pcregexp.pas.
247    
248     6. A Windows user reported a minor discrepancy with test 2, which turned out
249        to be caused by a trailing space on an input line that had got lost in his
250        copy. The trailing space was an accident, so I've just removed it.
251    
252     7. Add -Wl,-R... flags in pcre-config.in for *BSD* systems, as I'm told
253        that is needed.
254    
255   8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)   8. Mark ucp_table (in ucptable.h) and ucp_gentype (in pcre_ucp_searchfuncs.c)
256      as "const" (a) because they are and (b) because it helps the PHP      as "const" (a) because they are and (b) because it helps the PHP
257      maintainers who have recently made a script to detect big data structures      maintainers who have recently made a script to detect big data structures
258      in the php code that should be moved to the .rodata section. I remembered      in the php code that should be moved to the .rodata section. I remembered
259      to update Builducptable as well, so it won't revert if ucptable.h is ever      to update Builducptable as well, so it won't revert if ucptable.h is ever
260      re-created.      re-created.
261    
262   9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,   9. Added some extra #ifdef SUPPORT_UTF8 conditionals into pcretest.c,
263      pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in      pcre_printint.src, pcre_compile.c, pcre_study.c, and pcre_tables.c, in
264      order to be able to cut out the UTF-8 tables in the latter when UTF-8      order to be able to cut out the UTF-8 tables in the latter when UTF-8
265      support is not required. This saves 1.5-2K of code, which is important in      support is not required. This saves 1.5-2K of code, which is important in
266      some applications.      some applications.
267    
268        Later: more #ifdefs are needed in pcre_ord2utf8.c and pcre_valid_utf8.c
269        so as not to refer to the tables, even though these functions will never be
270        called when UTF-8 support is disabled. Otherwise there are problems with a
271        shared library.
272    
273    10. Fixed two bugs in the emulated memmove() function in pcre_internal.h:
274    
275        (a) It was defining its arguments as char * instead of void *.
276    
277        (b) It was assuming that all moves were upwards in memory; this was true
278            a long time ago when I wrote it, but is no longer the case.
279    
280        The emulated memove() is provided for those environments that have neither
281        memmove() nor bcopy(). I didn't think anyone used it these days, but that
282        is clearly not the case, as these two bugs were recently reported.
283    
284    11. The script PrepareRelease is now distributed: it calls 132html, CleanTxt,
285        and Detrail to create the HTML documentation, the .txt form of the man
286        pages, and it removes trailing spaces from listed files. It also creates
287        pcre.h.generic and config.h.generic from pcre.h and config.h. In the latter
288        case, it wraps all the #defines with #ifndefs. This script should be run
289        before "make dist".
290    
291    12. Fixed two fairly obscure bugs concerned with quantified caseless matching
292        with Unicode property support.
293    
294        (a) For a maximizing quantifier, if the two different cases of the
295            character were of different lengths in their UTF-8 codings (there are
296            some cases like this - I found 11), and the matching function had to
297            back up over a mixture of the two cases, it incorrectly assumed they
298            were both the same length.
299    
300        (b) When PCRE was configured to use the heap rather than the stack for
301            recursion during matching, it was not correctly preserving the data for
302            the other case of a UTF-8 character when checking ahead for a match
303            while processing a minimizing repeat. If the check also involved
304            matching a wide character, but failed, corruption could cause an
305            erroneous result when trying to check for a repeat of the original
306            character.
307    
308    13. Some tidying changes to the testing mechanism:
309    
310        (a) The RunTest script now detects the internal link size and whether there
311            is UTF-8 and UCP support by running ./pcretest -C instead of relying on
312            values substituted by "configure". (The RunGrepTest script already did
313            this for UTF-8.) The configure.ac script no longer substitutes the
314            relevant variables.
315    
316        (b) The debugging options /B and /D in pcretest show the compiled bytecode
317            with length and offset values. This means that the output is different
318            for different internal link sizes. Test 2 is skipped for link sizes
319            other than 2 because of this, bypassing the problem. Unfortunately,
320            there was also a test in test 3 (the locale tests) that used /B and
321            failed for link sizes other than 2. Rather than cut the whole test out,
322            I have added a new /Z option to pcretest that replaces the length and
323            offset values with spaces. This is now used to make test 3 independent
324            of link size. (Test 2 will be tidied up later.)
325    
326    14. If erroroffset was passed as NULL to pcre_compile, it provoked a
327        segmentation fault instead of returning the appropriate error message.
328    
329    15. In multiline mode when the newline sequence was set to "any", the pattern
330        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
331        This doesn't seem right; it now treats the CRLF combination as the line
332        ending, and so does not match in that case. It's only a pattern such as ^$
333        that would hit this one: something like ^ABC$ would have failed after \r
334        and then tried again after \r\n.
335    
336    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
337        in an attempt to make files that differ only in their line terminators
338        compare equal. This works on Linux.
339    
340    17. Under certain error circumstances pcregrep might try to free random memory
341        as it exited. This is now fixed, thanks to valgrind.
342    
343    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
344        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
345        was because its rules for how to advance for /g after matching an empty
346        string at the end of a line did not allow for this case. They now check for
347        it specially.
348    
349    20. pcretest is supposed to handle patterns and data of any length, by
350        extending its buffers when necessary. It was getting this wrong when the
351        buffer for a data line had to be extended.
352    
353    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
354        CRLF as a newline sequence.
355    
356    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
357        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
358        I have nevertheless tidied it up.
359    
360    23. Added some casts to kill warnings from HP-UX ia64 compiler.
361    
362    24. Added a man page for pcre-config.
363    
364    
365  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
366  ---------------------  ---------------------

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