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revision 164 by ph10, Fri May 4 15:11:14 2007 UTC revision 312 by ph10, Wed Jan 23 18:02:23 2008 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.2 01-May-07  Version 7.6 21-Jan-08
5    ---------------------
7    1.  A character class containing a very large number of characters with
8        codepoints greater than 255 (in UTF-8 mode, of course) caused a buffer
9        overflow.
11    2.  Patch to cut out the "long long" test in pcrecpp_unittest when
12        HAVE_LONG_LONG is not defined.
14    3.  Applied Christian Ehrlicher's patch to update the CMake build files to
15        bring them up to date and include new features. This patch includes:
17        - Fixed PH's badly added libz and libbz2 support.
18        - Fixed a problem with static linking.
19        - Added pcredemo. [But later removed - see 7 below.]
20        - Fixed dftables problem and added an option.
21        - Added a number of HAVE_XXX tests, including HAVE_WINDOWS_H and
22            HAVE_LONG_LONG.
23        - Added readline support for pcretest.
24        - Added an listing of the option settings after cmake has run.
26    4.  A user submitted a patch to Makefile that makes it easy to created a dll
27        under mingw. I added stuff to Makefile.am that cause it to include this
28        special target, without affecting anything else.
30    5.  Applied Craig's patch that moves no_arg into the RE class in the C++ code.
31        This is an attempt to solve the reported problem "pcrecpp::no_arg is not
32        exported in the Windows port". It has not yet been confirmed that the patch
33        solves the problem, but it does no harm.
35    6.  Applied Sheri's patch to CMakeLists.txt to add NON_STANDARD_LIB_PREFIX and
36        NON_STANDARD_LIB_SUFFIX and correct the comment about stack recursion.
38    7.  Remove the automatic building of pcredemo from the ./configure system and
39        from CMakeLists.txt. The whole idea of pcredemo.c is that it is an example
40        of a program that users should build themselves after PCRE is installed, so
41        building it automatically is not really right. What is more, it gave
42        trouble in some build environments.
45    Version 7.5 10-Jan-08
46    ---------------------
48    1.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
49        values in parens when parsing an RE using the C++ wrapper."
51    2.  Negative specials like \S did not work in character classes in UTF-8 mode.
52        Characters greater than 255 were excluded from the class instead of being
53        included.
55    3.  The same bug as (2) above applied to negated POSIX classes such as
56        [:^space:].
58    4.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
59        defined or documented. It seems to have been a typo for PCRE_STATIC, so
60        I have changed it.
62    5.  The construct (?&) was not diagnosed as a syntax error (it referenced the
63        first named subpattern) and a construct such as (?&a) would reference the
64        first named subpattern whose name started with "a" (in other words, the
65        length check was missing). Both these problems are fixed. "Subpattern name
66        expected" is now given for (?&) (a zero-length name), and this patch also
67        makes it give the same error for \k'' (previously it complained that that
68        was a reference to a non-existent subpattern).
70    6.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
71        this is right because (?- can be followed by option settings as well as by
72        digits. I have, however, made the messages clearer.
74    7.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
75        than the number used in the conditional) now cause a compile-time error.
76        This is actually not compatible with Perl, which accepts such patterns, but
77        treats the conditional as always being FALSE (as PCRE used to), but it
78        seems to me that giving a diagnostic is better.
80    8.  Change "alphameric" to the more common word "alphanumeric" in comments
81        and messages.
83    9.  Fix two occurrences of "backslash" in comments that should have been
84        "backspace".
86    10. Remove two redundant lines of code that can never be obeyed (their function
87        was moved elsewhere).
89    11. The program that makes PCRE's Unicode character property table had a bug
90        which caused it to generate incorrect table entries for sequences of
91        characters that have the same character type, but are in different scripts.
92        It amalgamated them into a single range, with the script of the first of
93        them. In other words, some characters were in the wrong script. There were
94        thirteen such cases, affecting characters in the following ranges:
96          U+002b0 - U+002c1
97          U+0060c - U+0060d
98          U+0061e - U+00612
99          U+0064b - U+0065e
100          U+0074d - U+0076d
101          U+01800 - U+01805
102          U+01d00 - U+01d77
103          U+01d9b - U+01dbf
104          U+0200b - U+0200f
105          U+030fc - U+030fe
106          U+03260 - U+0327f
107          U+0fb46 - U+0fbb1
108          U+10450 - U+1049d
110    12. The -o option (show only the matching part of a line) for pcregrep was not
111        compatible with GNU grep in that, if there was more than one match in a
112        line, it showed only the first of them. It now behaves in the same way as
113        GNU grep.
115    13. If the -o and -v options were combined for pcregrep, it printed a blank
116        line for every non-matching line. GNU grep prints nothing, and pcregrep now
117        does the same. The return code can be used to tell if there were any
118        non-matching lines.
120    14. Added --file-offsets and --line-offsets to pcregrep.
122    15. The pattern (?=something)(?R) was not being diagnosed as a potentially
123        infinitely looping recursion. The bug was that positive lookaheads were not
124        being skipped when checking for a possible empty match (negative lookaheads
125        and both kinds of lookbehind were skipped).
127    16. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
128        inclusion of <windows.h> to before rather than after the definition of
129        INVALID_FILE_ATTRIBUTES (patch from David Byron).
131    17. Specifying a possessive quantifier with a specific limit for a Unicode
132        character property caused pcre_compile() to compile bad code, which led at
133        runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
134        are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
135        caused the error; without that there was no problem.
137    18. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
139    19. Added --enable-pcretest-libreadline.
141    20. In pcrecpp.cc, the variable 'count' was incremented twice in
142        RE::GlobalReplace(). As a result, the number of replacements returned was
143        double what it should be. I removed one of the increments, but Craig sent a
144        later patch that removed the other one (the right fix) and added unit tests
145        that check the return values (which was not done before).
147    21. Several CMake things:
149        (1) Arranged that, when cmake is used on Unix, the libraries end up with
150            the names libpcre and libpcreposix, not just pcre and pcreposix.
152        (2) The above change means that pcretest and pcregrep are now correctly
153            linked with the newly-built libraries, not previously installed ones.
157    22. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
158        crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
159        UTF-8 newline character). The key issue is that the pattern starts .*;
160        this means that the match must be either at the beginning, or after a
161        newline. The bug was in the code for advancing after a failed match and
162        checking that the new position followed a newline. It was not taking
163        account of UTF-8 characters correctly.
165    23. PCRE was behaving differently from Perl in the way it recognized POSIX
166        character classes. PCRE was not treating the sequence [:...:] as a
167        character class unless the ... were all letters. Perl, however, seems to
168        allow any characters between [: and :], though of course it rejects as
169        unknown any "names" that contain non-letters, because all the known class
170        names consist only of letters. Thus, Perl gives an error for [[:1234:]],
171        for example, whereas PCRE did not - it did not recognize a POSIX character
172        class. This seemed a bit dangerous, so the code has been changed to be
173        closer to Perl. The behaviour is not identical to Perl, because PCRE will
174        diagnose an unknown class for, for example, [[:l\ower:]] where Perl will
175        treat it as [[:lower:]]. However, PCRE does now give "unknown" errors where
176        Perl does, and where it didn't before.
178    24. Rewrite so as to remove the single use of %n from pcregrep because in some
179        Windows environments %n is disabled by default.
182    Version 7.4 21-Sep-07
183    ---------------------
185    1.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
186        means that a class such as [\s] counted as "explicit reference to CR or
187        LF". That isn't really right - the whole point of the change was to try to
188        help when there was an actual mention of one of the two characters. So now
189        the change happens only if \r or \n (or a literal CR or LF) character is
190        encountered.
192    2.  The 32-bit options word was also used for 6 internal flags, but the numbers
193        of both had grown to the point where there were only 3 bits left.
194        Fortunately, there was spare space in the data structure, and so I have
195        moved the internal flags into a new 16-bit field to free up more option
196        bits.
198    3.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
199        but did not set the internal JCHANGED flag - either of these is enough to
200        control the way the "get" function works - but the PCRE_INFO_JCHANGED
201        facility is supposed to tell if (?J) was ever used, so now (?J) at the
202        start sets both bits.
204    4.  Added options (at build time, compile time, exec time) to change \R from
205        matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
207    5.  doc/pcresyntax.html was missing from the distribution.
209    6.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
210        compatibility, even though it is no longer used.
212    7.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
213        strtoull to pcrecpp.cc to select the available functions in WIN32 when the
214        windows.h file is present (where different names are used). [This was
215        reversed later after testing - see 16 below.]
217    8.  Changed all #include <config.h> to #include "config.h". There were also
218        some further <pcre.h> cases that I changed to "pcre.h".
220    9.  When pcregrep was used with the --colour option, it missed the line ending
221        sequence off the lines that it output.
223    10. It was pointed out to me that arrays of string pointers cause lots of
224        relocations when a shared library is dynamically loaded. A technique of
225        using a single long string with a table of offsets can drastically reduce
226        these. I have refactored PCRE in four places to do this. The result is
227        dramatic:
229          Originally:                          290
230          After changing UCP table:            187
231          After changing error message table:   43
232          After changing table of "verbs"       36
233          After changing table of Posix names   22
235        Thanks to the folks working on Gregex for glib for this insight.
237    11. --disable-stack-for-recursion caused compiling to fail unless -enable-
238        unicode-properties was also set.
240    12. Updated the tests so that they work when \R is defaulted to ANYCRLF.
242    13. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
243        checked only for CRLF.
245    14. Added casts to pcretest.c to avoid compiler warnings.
247    15. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
249    16. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
250        and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
251        entirely. This removes changes made in 7 above.
253    17. The CMake files have been updated, and there is now more information about
254        building with CMake in the NON-UNIX-USE document.
257    Version 7.3 28-Aug-07
258    ---------------------
260     1. In the rejigging of the build system that eventually resulted in 7.1, the
261        line "#include <pcre.h>" was included in pcre_internal.h. The use of angle
262        brackets there is not right, since it causes compilers to look for an
263        installed pcre.h, not the version that is in the source that is being
264        compiled (which of course may be different). I have changed it back to:
266          #include "pcre.h"
268        I have a vague recollection that the change was concerned with compiling in
269        different directories, but in the new build system, that is taken care of
270        by the VPATH setting the Makefile.
272     2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
273        when the subject happened to end in the byte 0x85 (e.g. if the last
274        character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
275        characters but of course it shouldn't be taken as a newline when it is part
276        of another character. The bug was that, for an unlimited repeat of . in
277        not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
278        characters when looking for a newline.
280     3. A small performance improvement in the DOTALL UTF-8 mode .* case.
282     4. Debugging: adjusted the names of opcodes for different kinds of parentheses
283        in debug output.
285     5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
286        long printing in the pcrecpp unittest when running under MinGW.
288     6. ESC_K was left out of the EBCDIC table.
290     7. Change 7.0/38 introduced a new limit on the number of nested non-capturing
291        parentheses; I made it 1000, which seemed large enough. Unfortunately, the
292        limit also applies to "virtual nesting" when a pattern is recursive, and in
293        this case 1000 isn't so big. I have been able to remove this limit at the
294        expense of backing off one optimization in certain circumstances. Normally,
295        when pcre_exec() would call its internal match() function recursively and
296        immediately return the result unconditionally, it uses a "tail recursion"
297        feature to save stack. However, when a subpattern that can match an empty
298        string has an unlimited repetition quantifier, it no longer makes this
299        optimization. That gives it a stack frame in which to save the data for
300        checking that an empty string has been matched. Previously this was taken
301        from the 1000-entry workspace that had been reserved. So now there is no
302        explicit limit, but more stack is used.
304     8. Applied Daniel's patches to solve problems with the import/export magic
305        syntax that is required for Windows, and which was going wrong for the
306        pcreposix and pcrecpp parts of the library. These were overlooked when this
307        problem was solved for the main library.
309     9. There were some crude static tests to avoid integer overflow when computing
310        the size of patterns that contain repeated groups with explicit upper
311        limits. As the maximum quantifier is 65535, the maximum group length was
312        set at 30,000 so that the product of these two numbers did not overflow a
313        32-bit integer. However, it turns out that people want to use groups that
314        are longer than 30,000 bytes (though not repeat them that many times).
315        Change 7.0/17 (the refactoring of the way the pattern size is computed) has
316        made it possible to implement the integer overflow checks in a much more
317        dynamic way, which I have now done. The artificial limitation on group
318        length has been removed - we now have only the limit on the total length of
319        the compiled pattern, which depends on the LINK_SIZE setting.
321    10. Fixed a bug in the documentation for get/copy named substring when
322        duplicate names are permitted. If none of the named substrings are set, the
323        functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
324        empty string.
326    11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
327        instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
328        because the ] is interpreted as the first data character and the
329        terminating ] is not found. PCRE has been made compatible with Perl in this
330        regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
331        cause memory overwriting.
333    10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
334        string has been matched (to stop an infinite loop). It was not recognizing
335        a conditional subpattern that could match an empty string if that
336        subpattern was within another subpattern. For example, it looped when
337        trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
338        condition was not nested. This bug has been fixed.
340    12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
341        past the start of the subject in the presence of bytes with the top bit
342        set, for example "\x8aBCD".
344    13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
345        (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
347    14. Optimized (?!) to (*FAIL).
349    15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
350        This restricts code points to be within the range 0 to 0x10FFFF, excluding
351        the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
352        full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
353        does: it's just the validity check that is more restrictive.
355    16. Inserted checks for integer overflows during escape sequence (backslash)
356        processing, and also fixed erroneous offset values for syntax errors during
357        backslash processing.
359    17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
360        for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
362    18. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
363        caused an overrun.
365    19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
366        something other than just ASCII characters) inside a group that had an
367        unlimited repeat caused a loop at compile time (while checking to see
368        whether the group could match an empty string).
370    20. Debugging a pattern containing \p or \P could cause a crash. For example,
371        [\P{Any}] did so. (Error in the code for printing property names.)
373    21. An orphan \E inside a character class could cause a crash.
375    22. A repeated capturing bracket such as (A)? could cause a wild memory
376        reference during compilation.
378    23. There are several functions in pcre_compile() that scan along a compiled
379        expression for various reasons (e.g. to see if it's fixed length for look
380        behind). There were bugs in these functions when a repeated \p or \P was
381        present in the pattern. These operators have additional parameters compared
382        with \d, etc, and these were not being taken into account when moving along
383        the compiled data. Specifically:
385        (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
386            length.
388        (b) An item such as \pL+ within a repeated group could cause crashes or
389            loops.
391        (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
392            "reference to non-existent subpattern" error.
394        (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
396    24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
397        characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
399    25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
401    26. Patterns such as [\P{Yi}A] which include \p or \P and just one other
402        character were causing crashes (broken optimization).
404    27. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
405        \p or \P) caused a compile-time loop.
407    28. More problems have arisen in unanchored patterns when CRLF is a valid line
408        break. For example, the unstudied pattern [\r\n]A does not match the string
409        "\r\nA" because change 7.0/46 below moves the current point on by two
410        characters after failing to match at the start. However, the pattern \nA
411        *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
412        the same is true. There doesn't seem any very clean way out of this, but
413        what I have chosen to do makes the common cases work: PCRE now takes note
414        of whether there can be an explicit match for \r or \n anywhere in the
415        pattern, and if so, 7.0/46 no longer applies. As part of this change,
416        there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
417        pattern has explicit CR or LF references.
419    29. Added (*CR) etc for changing newline setting at start of pattern.
422    Version 7.2 19-Jun-07
423  ---------------------  ---------------------
425   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 429  Version 7.2 01-May-07
429      to make them independent of the local environment's newline setting.      to make them independent of the local environment's newline setting.
431   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.
433   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
434      was not 2, because the output contained actual offsets. The recent new      was not 2, because the output contained actual offsets. The recent new
435      "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
436      usable with all link sizes.      usable with all link sizes.
438   5. Implemented Stan Switzer's goto replacement for longjmp() when not using   5. Implemented Stan Switzer's goto replacement for longjmp() when not using
439      stack recursion. This gives a massive performance boost under BSD, but just      stack recursion. This gives a massive performance boost under BSD, but just
440      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
441      in all cases.      in all cases.
443     6. Added more features from the forthcoming Perl 5.10:
445        (a) (?-n) (where n is a string of digits) is a relative subroutine or
446            recursion call. It refers to the nth most recently opened parentheses.
448        (b) (?+n) is also a relative subroutine call; it refers to the nth next
449            to be opened parentheses.
451        (c) Conditions that refer to capturing parentheses can be specified
452            relatively, for example, (?(-2)... or (?(+3)...
454        (d) \K resets the start of the current match so that everything before
455            is not part of it.
457        (e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible).
459        (f) \g{name} is another synonym - part of Perl 5.10's unification of
460            reference syntax.
462        (g) (?| introduces a group in which the numbering of parentheses in each
463            alternative starts with the same number.
465        (h) \h, \H, \v, and \V match horizontal and vertical whitespace.
467     7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and
470     8. A pattern such as  (.*(.)?)*  caused pcre_exec() to fail by either not
471        terminating or by crashing. Diagnosed by Viktor Griph; it was in the code
472        for detecting groups that can match an empty string.
474     9. A pattern with a very large number of alternatives (more than several
475        hundred) was running out of internal workspace during the pre-compile
476        phase, where pcre_compile() figures out how much memory will be needed. A
477        bit of new cunning has reduced the workspace needed for groups with
478        alternatives. The 1000-alternative test pattern now uses 12 bytes of
479        workspace instead of running out of the 4096 that are available.
481    10. Inserted some missing (unsigned int) casts to get rid of compiler warnings.
483    11. Applied patch from Google to remove an optimization that didn't quite work.
484        The report of the bug said:
486          pcrecpp::RE("a*").FullMatch("aaa") matches, while
487          pcrecpp::RE("a*?").FullMatch("aaa") does not, and
488          pcrecpp::RE("a*?\\z").FullMatch("aaa") does again.
490    12. If \p or \P was used in non-UTF-8 mode on a character greater than 127
491        it matched the wrong number of bytes.
494  Version 7.1 24-Apr-07  Version 7.1 24-Apr-07
495  ---------------------  ---------------------

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