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revision 127 by ph10, Mon Mar 19 11:44:45 2007 UTC revision 297 by ph10, Fri Jan 4 19:44:00 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.1 12-Mar-07  Version 7.5 04-Jan-08
5    ---------------------
6    
7    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
8        values in parens when parsing an RE using the C++ wrapper."
9    
10    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
11        Characters greater than 255 were excluded from the class instead of being
12        included.
13    
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
16    
17    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
18        defined or documented. It seems to have been a typo for PCRE_STATIC, so
19        I have changed it.
20    
21    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
22        first named subpattern) and a construct such as (?&a) would reference the
23        first named subpattern whose name started with "a" (in other words, the
24        length check was missing). Both these problems are fixed. "Subpattern name
25        expected" is now given for (?&) (a zero-length name), and this patch also
26        makes it give the same error for \k'' (previously it complained that that
27        was a reference to a non-existent subpattern).
28    
29    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
30        this is right because (?- can be followed by option settings as well as by
31        digits. I have, however, made the messages clearer.
32    
33    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
34        than the number used in the conditional) now cause a compile-time error.
35        This is actually not compatible with Perl, which accepts such patterns, but
36        treats the conditional as always being FALSE (as PCRE used to), but it
37        seems to me that giving a diagnostic is better.
38    
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
41    
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
44    
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
47    
48    11. The program that makes PCRE's Unicode character property table had a bug
49        which caused it to generate incorrect table entries for sequences of
50        characters that have the same character type, but are in different scripts.
51        It amalgamated them into a single range, with the script of the first of
52        them. In other words, some characters were in the wrong script. There were
53        thirteen such cases, affecting characters in the following ranges:
54    
55          U+002b0 - U+002c1
56          U+0060c - U+0060d
57          U+0061e - U+00612
58          U+0064b - U+0065e
59          U+0074d - U+0076d
60          U+01800 - U+01805
61          U+01d00 - U+01d77
62          U+01d9b - U+01dbf
63          U+0200b - U+0200f
64          U+030fc - U+030fe
65          U+03260 - U+0327f
66          U+0fb46 - U+0fbb1
67          U+10450 - U+1049d
68    
69    12. The -o option (show only the matching part of a line) for pcregrep was not
70        compatible with GNU grep in that, if there was more than one match in a
71        line, it showed only the first of them. It now behaves in the same way as
72        GNU grep.
73    
74    13. If the -o and -v options were combined for pcregrep, it printed a blank
75        line for every non-matching line. GNU grep prints nothing, and pcregrep now
76        does the same. The return code can be used to tell if there were any
77        non-matching lines.
78    
79    14. Added --file-offsets and --line-offsets to pcregrep.
80    
81    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
82        infinitely looping recursion. The bug was that positive lookaheads were not
83        being skipped when checking for a possible empty match (negative lookaheads
84        and both kinds of lookbehind were skipped).
85    
86    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
87        inclusion of <windows.h> to before rather than after the definition of
88        INVALID_FILE_ATTRIBUTES (patch from David Byron).
89    
90    17. Specifying a possessive quantifier with a specific limit for a Unicode
91        character property caused pcre_compile() to compile bad code, which led at
92        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
93        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
94        caused the error; without that there was no problem.
95    
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
97    
98    19. Added --enable-pcretest-libreadline.
99    
100    20. In pcrecpp.cc, the variable 'count' was incremented twice in
101        RE::GlobalReplace(). As a result, the number of replacements returned was
102        double what it should be. I removed one of the increments, but Craig sent a
103        later patch that removed the other one (the right fix) and added unit tests
104        that check the return values (which was not done before).
105    
106    21. Several CMake things:
107    
108        (1) Arranged that, when cmake is used on Unix, the libraries end up with
109            the names libpcre and libpcreposix, not just pcre and pcreposix.
110    
111        (2) The above change means that pcretest and pcregrep are now correctly
112            linked with the newly-built libraries, not previously installed ones.
113    
114        (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
115    
116    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
117        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
118        UTF-8 newline character). The key issue is that the pattern starts .*;
119        this means that the match must be either at the beginning, or after a
120        newline. The bug was in the code for advancing after a failed match and
121        checking that the new position followed a newline. It was not taking
122        account of UTF-8 characters correctly.
123    
124    23. PCRE was behaving differently from Perl in the way it recognized POSIX
125        character classes. PCRE was not treating the sequence [:...:] as a
126        character class unless the ... were all letters. Perl, however, seems to
127        allow any characters between [: and :], though of course it rejects as
128        unknown any "names" that contain non-letters, because all the known class
129        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
130        for example, whereas PCRE did not - it did not recognize a POSIX character
131        class. This seemed a bit dangerous, so the code has been changed to be
132        closer to Perl. The behaviour is not identical to Perl, because PCRE will
133        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
134        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
135        Perl does, and where it didn't before.
136    
137    24. Rewrite so as to remove the single use of %n from pcregrep because in some
138        Windows environments %n is disabled by default.
139    
140    
141    Version 7.4 21-Sep-07
142    ---------------------
143    
144    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
145        means that a class such as [\s] counted as "explicit reference to CR or
146        LF". That isn't really right - the whole point of the change was to try to
147        help when there was an actual mention of one of the two characters. So now
148        the change happens only if \r or \n (or a literal CR or LF) character is
149        encountered.
150    
151    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
152        of both had grown to the point where there were only 3 bits left.
153        Fortunately, there was spare space in the data structure, and so I have
154        moved the internal flags into a new 16-bit field to free up more option
155        bits.
156    
157    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
158        but did not set the internal JCHANGED flag - either of these is enough to
159        control the way the "get" function works - but the PCRE_INFO_JCHANGED
160        facility is supposed to tell if (?J) was ever used, so now (?J) at the
161        start sets both bits.
162    
163    4.  Added options (at build time, compile time, exec time) to change \R from
164        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
165    
166    5.  doc/pcresyntax.html was missing from the distribution.
167    
168    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
169        compatibility, even though it is no longer used.
170    
171    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
172        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
173        windows.h file is present (where different names are used). [This was
174        reversed later after testing - see 16 below.]
175    
176    8.  Changed all #include <config.h> to #include "config.h". There were also
177        some further <pcre.h> cases that I changed to "pcre.h".
178    
179    9.  When pcregrep was used with the --colour option, it missed the line ending
180        sequence off the lines that it output.
181    
182    10. It was pointed out to me that arrays of string pointers cause lots of
183        relocations when a shared library is dynamically loaded. A technique of
184        using a single long string with a table of offsets can drastically reduce
185        these. I have refactored PCRE in four places to do this. The result is
186        dramatic:
187    
188          Originally:                          290
189          After changing UCP table:            187
190          After changing error message table:   43
191          After changing table of "verbs"       36
192          After changing table of Posix names   22
193    
194        Thanks to the folks working on Gregex for glib for this insight.
195    
196    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
197        unicode-properties was also set.
198    
199    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
200    
201    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
202        checked only for CRLF.
203    
204    14. Added casts to pcretest.c to avoid compiler warnings.
205    
206    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
207    
208    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
209        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
210        entirely. This removes changes made in 7 above.
211    
212    17. The CMake files have been updated, and there is now more information about
213        building with CMake in the NON-UNIX-USE document.
214    
215    
216    Version 7.3 28-Aug-07
217    ---------------------
218    
219     1. In the rejigging of the build system that eventually resulted in 7.1, the
220        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
221        brackets there is not right, since it causes compilers to look for an
222        installed pcre.h, not the version that is in the source that is being
223        compiled (which of course may be different). I have changed it back to:
224    
225          #include "pcre.h"
226    
227        I have a vague recollection that the change was concerned with compiling in
228        different directories, but in the new build system, that is taken care of
229        by the VPATH setting the Makefile.
230    
231     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
232        when the subject happened to end in the byte 0x85 (e.g. if the last
233        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
234        characters but of course it shouldn't be taken as a newline when it is part
235        of another character. The bug was that, for an unlimited repeat of . in
236        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
237        characters when looking for a newline.
238    
239     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
240    
241     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
242        in debug output.
243    
244     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
245        long printing in the pcrecpp unittest when running under MinGW.
246    
247     6. ESC_K was left out of the EBCDIC table.
248    
249     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
250        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
251        limit also applies to "virtual nesting" when a pattern is recursive, and in
252        this case 1000 isn't so big. I have been able to remove this limit at the
253        expense of backing off one optimization in certain circumstances. Normally,
254        when pcre_exec() would call its internal match() function recursively and
255        immediately return the result unconditionally, it uses a "tail recursion"
256        feature to save stack. However, when a subpattern that can match an empty
257        string has an unlimited repetition quantifier, it no longer makes this
258        optimization. That gives it a stack frame in which to save the data for
259        checking that an empty string has been matched. Previously this was taken
260        from the 1000-entry workspace that had been reserved. So now there is no
261        explicit limit, but more stack is used.
262    
263     8. Applied Daniel's patches to solve problems with the import/export magic
264        syntax that is required for Windows, and which was going wrong for the
265        pcreposix and pcrecpp parts of the library. These were overlooked when this
266        problem was solved for the main library.
267    
268     9. There were some crude static tests to avoid integer overflow when computing
269        the size of patterns that contain repeated groups with explicit upper
270        limits. As the maximum quantifier is 65535, the maximum group length was
271        set at 30,000 so that the product of these two numbers did not overflow a
272        32-bit integer. However, it turns out that people want to use groups that
273        are longer than 30,000 bytes (though not repeat them that many times).
274        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
275        made it possible to implement the integer overflow checks in a much more
276        dynamic way, which I have now done. The artificial limitation on group
277        length has been removed - we now have only the limit on the total length of
278        the compiled pattern, which depends on the LINK_SIZE setting.
279    
280    10. Fixed a bug in the documentation for get/copy named substring when
281        duplicate names are permitted. If none of the named substrings are set, the
282        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
283        empty string.
284    
285    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
286        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
287        because the ] is interpreted as the first data character and the
288        terminating ] is not found. PCRE has been made compatible with Perl in this
289        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
290        cause memory overwriting.
291    
292    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
293        string has been matched (to stop an infinite loop). It was not recognizing
294        a conditional subpattern that could match an empty string if that
295        subpattern was within another subpattern. For example, it looped when
296        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
297        condition was not nested. This bug has been fixed.
298    
299    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
300        past the start of the subject in the presence of bytes with the top bit
301        set, for example "\x8aBCD".
302    
303    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
304        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
305    
306    14. Optimized (?!) to (*FAIL).
307    
308    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
309        This restricts code points to be within the range 0 to 0x10FFFF, excluding
310        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
311        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
312        does: it's just the validity check that is more restrictive.
313    
314    16. Inserted checks for integer overflows during escape sequence (backslash)
315        processing, and also fixed erroneous offset values for syntax errors during
316        backslash processing.
317    
318    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
319        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
320    
321    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
322        caused an overrun.
323    
324    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
325        something other than just ASCII characters) inside a group that had an
326        unlimited repeat caused a loop at compile time (while checking to see
327        whether the group could match an empty string).
328    
329    20. Debugging a pattern containing \p or \P could cause a crash. For example,
330        [\P{Any}] did so. (Error in the code for printing property names.)
331    
332    21. An orphan \E inside a character class could cause a crash.
333    
334    22. A repeated capturing bracket such as (A)? could cause a wild memory
335        reference during compilation.
336    
337    23. There are several functions in pcre_compile() that scan along a compiled
338        expression for various reasons (e.g. to see if it's fixed length for look
339        behind). There were bugs in these functions when a repeated \p or \P was
340        present in the pattern. These operators have additional parameters compared
341        with \d, etc, and these were not being taken into account when moving along
342        the compiled data. Specifically:
343    
344        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
345            length.
346    
347        (b) An item such as \pL+ within a repeated group could cause crashes or
348            loops.
349    
350        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
351            "reference to non-existent subpattern" error.
352    
353        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
354    
355    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
356        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
357    
358    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
359    
360    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
361        character were causing crashes (broken optimization).
362    
363    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
364        \p or \P) caused a compile-time loop.
365    
366    28. More problems have arisen in unanchored patterns when CRLF is a valid line
367        break. For example, the unstudied pattern [\r\n]A does not match the string
368        "\r\nA" because change 7.0/46 below moves the current point on by two
369        characters after failing to match at the start. However, the pattern \nA
370        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
371        the same is true. There doesn't seem any very clean way out of this, but
372        what I have chosen to do makes the common cases work: PCRE now takes note
373        of whether there can be an explicit match for \r or \n anywhere in the
374        pattern, and if so, 7.0/46 no longer applies. As part of this change,
375        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
376        pattern has explicit CR or LF references.
377    
378    29. Added (*CR) etc for changing newline setting at start of pattern.
379    
380    
381    Version 7.2 19-Jun-07
382    ---------------------
383    
384     1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
385        which is apparently normally available under Windows.
386    
387     2. Re-jig the pcregrep tests with different newline settings in an attempt
388        to make them independent of the local environment's newline setting.
389    
390     3. Add code to configure.ac to remove -g from the CFLAGS default settings.
391    
392     4. Some of the "internals" tests were previously cut out when the link size
393        was not 2, because the output contained actual offsets. The recent new
394        "Z" feature of pcretest means that these can be cut out, making the tests
395        usable with all link sizes.
396    
397     5. Implemented Stan Switzer's goto replacement for longjmp() when not using
398        stack recursion. This gives a massive performance boost under BSD, but just
399        a small improvement under Linux. However, it saves one field in the frame
400        in all cases.
401    
402     6. Added more features from the forthcoming Perl 5.10:
403    
404        (a) (?-n) (where n is a string of digits) is a relative subroutine or
405            recursion call. It refers to the nth most recently opened parentheses.
406    
407        (b) (?+n) is also a relative subroutine call; it refers to the nth next
408            to be opened parentheses.
409    
410        (c) Conditions that refer to capturing parentheses can be specified
411            relatively, for example, (?(-2)... or (?(+3)...
412    
413        (d) \K resets the start of the current match so that everything before
414            is not part of it.
415    
416        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
417    
418        (f) \g{name} is another synonym - part of Perl 5.10's unification of
419            reference syntax.
420    
421        (g) (?| introduces a group in which the numbering of parentheses in each
422            alternative starts with the same number.
423    
424        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
425    
426     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
427        PCRE_INFO_JCHANGED.
428    
429     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
430        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
431        for detecting groups that can match an empty string.
432    
433     9. A pattern with a very large number of alternatives (more than several
434        hundred) was running out of internal workspace during the pre-compile
435        phase, where pcre_compile() figures out how much memory will be needed. A
436        bit of new cunning has reduced the workspace needed for groups with
437        alternatives. The 1000-alternative test pattern now uses 12 bytes of
438        workspace instead of running out of the 4096 that are available.
439    
440    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
441    
442    11. Applied patch from Google to remove an optimization that didn't quite work.
443        The report of the bug said:
444    
445          pcrecpp::RE("a*").FullMatch("aaa") matches, while
446          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
447          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
448    
449    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
450        it matched the wrong number of bytes.
451    
452    
453    Version 7.1 24-Apr-07
454  ---------------------  ---------------------
455    
456   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 33  Version 7.1 12-Mar-07 Line 482  Version 7.1 12-Mar-07
482   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan   5. Updated the support (such as it is) for Virtual Pascal, thanks to Stefan
483      Weber: (1) pcre_internal.h was missing some function renames; (2) updated      Weber: (1) pcre_internal.h was missing some function renames; (2) updated
484      makevp.bat for the current PCRE, using the additional files      makevp.bat for the current PCRE, using the additional files
485      makevp-compile.txt, makevp-linklib.txt, and pcregexp.pas.      makevp_c.txt, makevp_l.txt, and pcregexp.pas.
486    
487   6. A Windows user reported a minor discrepancy with test 2, which turned out   6. A Windows user reported a minor discrepancy with test 2, which turned out
488      to be caused by a trailing space on an input line that had got lost in his      to be caused by a trailing space on an input line that had got lost in his
# Line 116  Version 7.1 12-Mar-07 Line 565  Version 7.1 12-Mar-07
565  14. If erroroffset was passed as NULL to pcre_compile, it provoked a  14. If erroroffset was passed as NULL to pcre_compile, it provoked a
566      segmentation fault instead of returning the appropriate error message.      segmentation fault instead of returning the appropriate error message.
567    
568    15. In multiline mode when the newline sequence was set to "any", the pattern
569        ^$ would give a match between the \r and \n of a subject such as "A\r\nB".
570        This doesn't seem right; it now treats the CRLF combination as the line
571        ending, and so does not match in that case. It's only a pattern such as ^$
572        that would hit this one: something like ^ABC$ would have failed after \r
573        and then tried again after \r\n.
574    
575    16. Changed the comparison command for RunGrepTest from "diff -u" to "diff -ub"
576        in an attempt to make files that differ only in their line terminators
577        compare equal. This works on Linux.
578    
579    17. Under certain error circumstances pcregrep might try to free random memory
580        as it exited. This is now fixed, thanks to valgrind.
581    
582    19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string
583        "abc\r\n\r\n", it found an unwanted second match after the second \r. This
584        was because its rules for how to advance for /g after matching an empty
585        string at the end of a line did not allow for this case. They now check for
586        it specially.
587    
588    20. pcretest is supposed to handle patterns and data of any length, by
589        extending its buffers when necessary. It was getting this wrong when the
590        buffer for a data line had to be extended.
591    
592    21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or
593        CRLF as a newline sequence.
594    
595    22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut
596        out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but
597        I have nevertheless tidied it up.
598    
599    23. Added some casts to kill warnings from HP-UX ia64 compiler.
600    
601    24. Added a man page for pcre-config.
602    
603    
604  Version 7.0 19-Dec-06  Version 7.0 19-Dec-06
605  ---------------------  ---------------------

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