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revision 164 by ph10, Fri May 4 15:11:14 2007 UTC revision 298 by ph10, Thu Jan 10 17:09:12 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.2 01-May-07  Version 7.5 10-Jan-08
5    ---------------------
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."
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.
14    3.  The same bug as (2) above applied to negated POSIX classes such as
15        [:^space:].
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.
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).
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.
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.
39    8.  Change "alphameric" to the more common word "alphanumeric" in comments
40        and messages.
42    9.  Fix two occurrences of "backslash" in comments that should have been
43        "backspace".
45    10. Remove two redundant lines of code that can never be obeyed (their function
46        was moved elsewhere).
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:
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
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.
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.
79    14. Added --file-offsets and --line-offsets to pcregrep.
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).
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).
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.
96    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
98    19. Added --enable-pcretest-libreadline.
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).
106    21. Several CMake things:
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.
111        (2) The above change means that pcretest and pcregrep are now correctly
112            linked with the newly-built libraries, not previously installed ones.
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.
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.
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.
141    Version 7.4 21-Sep-07
142    ---------------------
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.
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.
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.
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.
166    5.  doc/pcresyntax.html was missing from the distribution.
168    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
169        compatibility, even though it is no longer used.
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.]
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".
179    9.  When pcregrep was used with the --colour option, it missed the line ending
180        sequence off the lines that it output.
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:
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
194        Thanks to the folks working on Gregex for glib for this insight.
196    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
197        unicode-properties was also set.
199    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
201    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
202        checked only for CRLF.
204    14. Added casts to pcretest.c to avoid compiler warnings.
206    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
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.
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.
216    Version 7.3 28-Aug-07
217    ---------------------
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:
225          #include "pcre.h"
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.
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.
239     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
241     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
242        in debug output.
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.
247     6. ESC_K was left out of the EBCDIC table.
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.
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.
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.
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.
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.
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.
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".
303    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
304        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
306    14. Optimized (?!) to (*FAIL).
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.
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.
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".
321    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
322        caused an overrun.
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).
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.)
332    21. An orphan \E inside a character class could cause a crash.
334    22. A repeated capturing bracket such as (A)? could cause a wild memory
335        reference during compilation.
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:
344        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
345            length.
347        (b) An item such as \pL+ within a repeated group could cause crashes or
348            loops.
350        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
351            "reference to non-existent subpattern" error.
353        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
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").
358    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
360    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
361        character were causing crashes (broken optimization).
363    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
364        \p or \P) caused a compile-time loop.
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.
378    29. Added (*CR) etc for changing newline setting at start of pattern.
381    Version 7.2 19-Jun-07
382  ---------------------  ---------------------
384   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,   1. If the fr_FR locale cannot be found for test 3, try the "french" locale,
# Line 11  Version 7.2 01-May-07 Line 388  Version 7.2 01-May-07
388      to make them independent of the local environment's newline setting.      to make them independent of the local environment's newline setting.
390   3. Add code to configure.ac to remove -g from the CFLAGS default settings.   3. Add code to configure.ac to remove -g from the CFLAGS default settings.
392   4. Some of the "internals" tests were previously cut out when the link size   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      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      "Z" feature of pcretest means that these can be cut out, making the tests
395      usable with all link sizes.      usable with all link sizes.
397   5. Implemented Stan Switzer's goto replacement for longjmp() when not using   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      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      a small improvement under Linux. However, it saves one field in the frame
400      in all cases.      in all cases.
402     6. Added more features from the forthcoming Perl 5.10:
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.
407        (b) (?+n) is also a relative subroutine call; it refers to the nth next
408            to be opened parentheses.
410        (c) Conditions that refer to capturing parentheses can be specified
411            relatively, for example, (?(-2)... or (?(+3)...
413        (d) \K resets the start of the current match so that everything before
414            is not part of it.
416        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
418        (f) \g{name} is another synonym - part of Perl 5.10's unification of
419            reference syntax.
421        (g) (?| introduces a group in which the numbering of parentheses in each
422            alternative starts with the same number.
424        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
426     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
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.
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.
440    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
442    11. Applied patch from Google to remove an optimization that didn't quite work.
443        The report of the bug said:
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.
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.
453  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
454  ---------------------  ---------------------

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