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ChangeLog for PCRE |
ChangeLog for PCRE |
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Version 7.1 12-Mar-07 |
Version 7.3 20-Aug-07 |
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1. In the rejigging of the build system that eventually resulted in 7.1, the |
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line "#include <pcre.h>" was included in pcre_internal.h. The use of angle |
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brackets there is not right, since it causes compilers to look for an |
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installed pcre.h, not the version that is in the source that is being |
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compiled (which of course may be different). I have changed it back to: |
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#include "pcre.h" |
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I have a vague recollection that the change was concerned with compiling in |
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different directories, but in the new build system, that is taken care of |
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by the VPATH setting the Makefile. |
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2. The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed |
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when the subject happened to end in the byte 0x85 (e.g. if the last |
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character was \x{1ec5}). *Character* 0x85 is one of the "any" newline |
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characters but of course it shouldn't be taken as a newline when it is part |
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of another character. The bug was that, for an unlimited repeat of . in |
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not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by |
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characters when looking for a newline. |
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3. A small performance improvement in the DOTALL UTF-8 mode .* case. |
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4. Debugging: adjusted the names of opcodes for different kinds of parentheses |
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in debug output. |
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5. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for |
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long printing in the pcrecpp unittest when running under MinGW. |
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6. ESC_K was left out of the EBCDIC table. |
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7. Change 7.0/38 introduced a new limit on the number of nested non-capturing |
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parentheses; I made it 1000, which seemed large enough. Unfortunately, the |
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limit also applies to "virtual nesting" when a pattern is recursive, and in |
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this case 1000 isn't so big. I have been able to remove this limit at the |
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expense of backing off one optimization in certain circumstances. Normally, |
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when pcre_exec() would call its internal match() function recursively and |
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immediately return the result unconditionally, it uses a "tail recursion" |
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feature to save stack. However, when a subpattern that can match an empty |
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string has an unlimited repetition quantifier, it no longer makes this |
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optimization. That gives it a stack frame in which to save the data for |
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checking that an empty string has been matched. Previously this was taken |
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from the 1000-entry workspace that had been reserved. So now there is no |
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explicit limit, but more stack is used. |
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8. Applied Daniel's patches to solve problems with the import/export magic |
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syntax that is required for Windows, and which was going wrong for the |
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pcreposix and pcrecpp parts of the library. These were overlooked when this |
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problem was solved for the main library. |
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9. There were some crude static tests to avoid integer overflow when computing |
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the size of patterns that contain repeated groups with explicit upper |
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limits. As the maximum quantifier is 65535, the maximum group length was |
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set at 30,000 so that the product of these two numbers did not overflow a |
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32-bit integer. However, it turns out that people want to use groups that |
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are longer than 30,000 bytes (though not repeat them that many times). |
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Change 7.0/17 (the refactoring of the way the pattern size is computed) has |
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made it possible to implement the integer overflow checks in a much more |
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dynamic way, which I have now done. The artificial limitation on group |
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length has been removed - we now have only the limit on the total length of |
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the compiled pattern, which depends on the LINK_SIZE setting. |
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10. Fixed a bug in the documentation for get/copy named substring when |
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duplicate names are permitted. If none of the named substrings are set, the |
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functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an |
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empty string. |
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11. Because Perl interprets \Q...\E at a high level, and ignores orphan \E |
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instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error, |
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because the ] is interpreted as the first data character and the |
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terminating ] is not found. PCRE has been made compatible with Perl in this |
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regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could |
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cause memory overwriting. |
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10. Like Perl, PCRE automatically breaks an unlimited repeat after an empty |
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string has been matched (to stop an infinite loop). It was not recognizing |
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a conditional subpattern that could match an empty string if that |
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subpattern was within another subpattern. For example, it looped when |
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trying to match (((?(1)X|))*) but it was OK with ((?(1)X|)*) where the |
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condition was not nested. This bug has been fixed. |
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12. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack |
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past the start of the subject in the presence of bytes with the top bit |
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set, for example "\x8aBCD". |
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13. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE), |
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(*SKIP), (*THEN), (*COMMIT), and (*ACCEPT). |
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14. Optimized (?!) to (*FAIL). |
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15. Updated the test for a valid UTF-8 string to conform to the later RFC 3629. |
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This restricts code points to be within the range 0 to 0x10FFFF, excluding |
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the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the |
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full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still |
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does: it's just the validity check that is more restrictive. |
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16. Inserted checks for integer overflows during escape sequence (backslash) |
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processing, and also fixed erroneous offset values for syntax errors during |
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backslash processing. |
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17. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above) |
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for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80". |
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18. An unterminated class in a pattern like (?1)\c[ with a "forward reference" |
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caused an overrun. |
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19. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with |
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something other than just ASCII characters) inside a group that had an |
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unlimited repeat caused a loop at compile time (while checking to see |
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whether the group could match an empty string). |
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20. Debugging a pattern containing \p or \P could cause a crash. For example, |
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[\P{Any}] did so. (Error in the code for printing property names.) |
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21. An orphan \E inside a character class could cause a crash. |
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22. A repeated capturing bracket such as (A)? could cause a wild memory |
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reference during compilation. |
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23. There are several functions in pcre_compile() that scan along a compiled |
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expression for various reasons (e.g. to see if it's fixed length for look |
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behind). There were bugs in these functions when a repeated \p or \P was |
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present in the pattern. These operators have additional parameters compared |
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with \d, etc, and these were not being taken into account when moving along |
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the compiled data. Specifically: |
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(a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed |
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length. |
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(b) An item such as \pL+ within a repeated group could cause crashes or |
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loops. |
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(c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect |
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"reference to non-existent subpattern" error. |
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(d) A pattern like (\P{Yi}{2}\277)? could loop at compile time. |
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24. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte |
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characters were involved (for example /\S{2}/8g with "A\x{a3}BC"). |
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25. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop. |
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26. Patterns such as [\P{Yi}A] which include \p or \P and just one other |
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character were causing crashes (broken optimization). |
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Version 7.2 19-Jun-07 |
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1. If the fr_FR locale cannot be found for test 3, try the "french" locale, |
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which is apparently normally available under Windows. |
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2. Re-jig the pcregrep tests with different newline settings in an attempt |
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to make them independent of the local environment's newline setting. |
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3. Add code to configure.ac to remove -g from the CFLAGS default settings. |
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4. Some of the "internals" tests were previously cut out when the link size |
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was not 2, because the output contained actual offsets. The recent new |
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"Z" feature of pcretest means that these can be cut out, making the tests |
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usable with all link sizes. |
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5. Implemented Stan Switzer's goto replacement for longjmp() when not using |
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stack recursion. This gives a massive performance boost under BSD, but just |
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a small improvement under Linux. However, it saves one field in the frame |
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in all cases. |
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6. Added more features from the forthcoming Perl 5.10: |
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(a) (?-n) (where n is a string of digits) is a relative subroutine or |
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recursion call. It refers to the nth most recently opened parentheses. |
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(b) (?+n) is also a relative subroutine call; it refers to the nth next |
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to be opened parentheses. |
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(c) Conditions that refer to capturing parentheses can be specified |
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relatively, for example, (?(-2)... or (?(+3)... |
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(d) \K resets the start of the current match so that everything before |
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is not part of it. |
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(e) \k{name} is synonymous with \k<name> and \k'name' (.NET compatible). |
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(f) \g{name} is another synonym - part of Perl 5.10's unification of |
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reference syntax. |
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(g) (?| introduces a group in which the numbering of parentheses in each |
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alternative starts with the same number. |
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(h) \h, \H, \v, and \V match horizontal and vertical whitespace. |
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7. Added two new calls to pcre_fullinfo(): PCRE_INFO_OKPARTIAL and |
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PCRE_INFO_JCHANGED. |
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8. A pattern such as (.*(.)?)* caused pcre_exec() to fail by either not |
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terminating or by crashing. Diagnosed by Viktor Griph; it was in the code |
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for detecting groups that can match an empty string. |
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9. A pattern with a very large number of alternatives (more than several |
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hundred) was running out of internal workspace during the pre-compile |
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phase, where pcre_compile() figures out how much memory will be needed. A |
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bit of new cunning has reduced the workspace needed for groups with |
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alternatives. The 1000-alternative test pattern now uses 12 bytes of |
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workspace instead of running out of the 4096 that are available. |
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10. Inserted some missing (unsigned int) casts to get rid of compiler warnings. |
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11. Applied patch from Google to remove an optimization that didn't quite work. |
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The report of the bug said: |
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pcrecpp::RE("a*").FullMatch("aaa") matches, while |
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pcrecpp::RE("a*?").FullMatch("aaa") does not, and |
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pcrecpp::RE("a*?\\z").FullMatch("aaa") does again. |
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12. If \p or \P was used in non-UTF-8 mode on a character greater than 127 |
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it matched the wrong number of bytes. |
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Version 7.1 24-Apr-07 |
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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 |
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in an attempt to make files that differ only in their line terminators |
in an attempt to make files that differ only in their line terminators |
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compare equal. This works on Linux. |
compare equal. This works on Linux. |
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17. Under certain error circumstances pcregrep might try to free random memory |
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as it exited. This is now fixed, thanks to valgrind. |
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19. In pcretest, if the pattern /(?m)^$/g<any> was matched against the string |
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"abc\r\n\r\n", it found an unwanted second match after the second \r. This |
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was because its rules for how to advance for /g after matching an empty |
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string at the end of a line did not allow for this case. They now check for |
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it specially. |
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20. pcretest is supposed to handle patterns and data of any length, by |
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extending its buffers when necessary. It was getting this wrong when the |
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buffer for a data line had to be extended. |
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21. Added PCRE_NEWLINE_ANYCRLF which is like ANY, but matches only CR, LF, or |
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CRLF as a newline sequence. |
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22. Code for handling Unicode properties in pcre_dfa_exec() wasn't being cut |
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out by #ifdef SUPPORT_UCP. This did no harm, as it could never be used, but |
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I have nevertheless tidied it up. |
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23. Added some casts to kill warnings from HP-UX ia64 compiler. |
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24. Added a man page for pcre-config. |
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Version 7.0 19-Dec-06 |
Version 7.0 19-Dec-06 |
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--------------------- |
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