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-revision 193 by ph10,
Mon Jul 30 11:34:18 2007 UTC
+revision 294 by ph10,
Sat Dec 29 16:55:59 2007 UTC
 Line 1
  ChangeLog for PCRE
  ------------------
- Version 7.3 05-Jul-07
+ Version 7.5 29-Dec-07
+ ---------------------
+.  Applied a patch from Craig: "This patch makes it possible to 'ignore'
+     values in parens when parsing an RE using the C++ wrapper."
+.  Negative specials like \S did not work in character classes in UTF-8 mode.
+     Characters greater than 255 were excluded from the class instead of being
+     included.
+.  The same bug as (2) above applied to negated POSIX classes such as
+     [:^space:].
+.  PCRECPP_STATIC was referenced in pcrecpp_internal.h, but nowhere was it
+     defined or documented. It seems to have been a typo for PCRE_STATIC, so
+     I have changed it.
+.  The construct (?&) was not diagnosed as a syntax error (it referenced the
+     first named subpattern) and a construct such as (?&a) would reference the
+     first named subpattern whose name started with "a" (in other words, the
+     length check was missing). Both these problems are fixed. "Subpattern name
+     expected" is now given for (?&) (a zero-length name), and this patch also
+     makes it give the same error for \k'' (previously it complained that that
+     was a reference to a non-existent subpattern).
+.  The erroneous patterns (?+-a) and (?-+a) give different error messages;
+     this is right because (?- can be followed by option settings as well as by
+     digits. I have, however, made the messages clearer.
+.  Patterns such as (?(1)a|b) (a pattern that contains fewer subpatterns
+     than the number used in the conditional) now cause a compile-time error.
+     This is actually not compatible with Perl, which accepts such patterns, but
+     treats the conditional as always being FALSE (as PCRE used to), but it
+     seems to me that giving a diagnostic is better.
+.  Change "alphameric" to the more common word "alphanumeric" in comments
+     and messages.
+.  Fix two occurrences of "backslash" in comments that should have been
+     "backspace".
+. Remove two redundant lines of code that can never be obeyed (their function
+     was moved elsewhere).
+. The program that makes PCRE's Unicode character property table had a bug
+     which caused it to generate incorrect table entries for sequences of
+     characters that have the same character type, but are in different scripts.
+     It amalgamated them into a single range, with the script of the first of
+     them. In other words, some characters were in the wrong script. There were
+     thirteen such cases, affecting characters in the following ranges:
+       U+002b0 - U+002c1
+       U+0060c - U+0060d
+       U+0061e - U+00612
+       U+0064b - U+0065e
+       U+0074d - U+0076d
+       U+01800 - U+01805
+       U+01d00 - U+01d77
+       U+01d9b - U+01dbf
+       U+0200b - U+0200f
+       U+030fc - U+030fe
+       U+03260 - U+0327f
+       U+0fb46 - U+0fbb1
+       U+10450 - U+1049d
+. The -o option (show only the matching part of a line) for pcregrep was not
+     compatible with GNU grep in that, if there was more than one match in a
+     line, it showed only the first of them. It now behaves in the same way as
+     GNU grep.
+. If the -o and -v options were combined for pcregrep, it printed a blank
+     line for every non-matching line. GNU grep prints nothing, and pcregrep now
+     does the same. The return code can be used to tell if there were any
+     non-matching lines.
+. Added --file-offsets and --line-offsets to pcregrep.
+. The pattern (?=something)(?R) was not being diagnosed as a potentially
+     infinitely looping recursion. The bug was that positive lookaheads were not
+     being skipped when checking for a possible empty match (negative lookaheads
+     and both kinds of lookbehind were skipped).
+. Fixed two typos in the Windows-only code in pcregrep.c, and moved the
+     inclusion of <windows.h> to before rather than after the definition of
+     INVALID_FILE_ATTRIBUTES (patch from David Byron).
+. Specifying a possessive quantifier with a specific limit for a Unicode
+     character property caused pcre_compile() to compile bad code, which led at
+     runtime to PCRE_ERROR_INTERNAL (-14). Examples of patterns that caused this
+     are: /\p{Zl}{2,3}+/8 and /\p{Cc}{2}+/8. It was the possessive "+" that
+     caused the error; without that there was no problem.
+. Added --enable-pcregrep-libz and --enable-pcregrep-libbz2.
+. Added --enable-pcretest-libreadline.
+. In pcrecpp.cc, the variable 'count' was incremented twice in
+     RE::GlobalReplace(). As a result, the number of replacements returned was
+     double what it should be. I have removed one of the increments.
+. Several CMake things:
+     (1) Arranged that, when cmake is used on Unix, the libraries end up with
+         the names libpcre and libpcreposix, not just pcre and pcreposix.
+     (2) The above change means that pcretest and pcregrep are now correctly
+         linked with the newly-built libraries, not previously installed ones.
+     (3) Added PCRE_SUPPORT_LIBREADLINE, PCRE_SUPPORT_LIBZ, PCRE_SUPPORT_LIBBZ2.
+. In UTF-8 mode, with newline set to "any", a pattern such as .*a.*=.b.*
+     crashed when matching a string such as a\x{2029}b (note that \x{2029} is a
+     UTF-8 newline character). The key issue is that the pattern starts .*;
+     this means that the match must be either at the beginning, or after a
+     newline. The bug was in the code for advancing after a failed match and
+     checking that the new position followed a newline. It was not taking
+     account of UTF-8 characters correctly.
+ Version 7.4 21-Sep-07
+ ---------------------
+.  Change 7.3/28 was implemented for classes by looking at the bitmap. This
+     means that a class such as [\s] counted as "explicit reference to CR or
+     LF". That isn't really right - the whole point of the change was to try to
+     help when there was an actual mention of one of the two characters. So now
+     the change happens only if \r or \n (or a literal CR or LF) character is
+     encountered.
+.  The 32-bit options word was also used for 6 internal flags, but the numbers
+     of both had grown to the point where there were only 3 bits left.
+     Fortunately, there was spare space in the data structure, and so I have
+     moved the internal flags into a new 16-bit field to free up more option
+     bits.
+.  The appearance of (?J) at the start of a pattern set the DUPNAMES option,
+     but did not set the internal JCHANGED flag - either of these is enough to
+     control the way the "get" function works - but the PCRE_INFO_JCHANGED
+     facility is supposed to tell if (?J) was ever used, so now (?J) at the
+     start sets both bits.
+.  Added options (at build time, compile time, exec time) to change \R from
+     matching any Unicode line ending sequence to just matching CR, LF, or CRLF.
+.  doc/pcresyntax.html was missing from the distribution.
+.  Put back the definition of PCRE_ERROR_NULLWSLIMIT, for backward
+     compatibility, even though it is no longer used.
+.  Added macro for snprintf to pcrecpp_unittest.cc and also for strtoll and
+     strtoull to pcrecpp.cc to select the available functions in WIN32 when the
+     windows.h file is present (where different names are used). [This was
+     reversed later after testing - see 16 below.]
+.  Changed all #include <config.h> to #include "config.h". There were also
+     some further <pcre.h> cases that I changed to "pcre.h".
+.  When pcregrep was used with the --colour option, it missed the line ending
+     sequence off the lines that it output.
+. It was pointed out to me that arrays of string pointers cause lots of
+     relocations when a shared library is dynamically loaded. A technique of
+     using a single long string with a table of offsets can drastically reduce
+     these. I have refactored PCRE in four places to do this. The result is
+     dramatic:
+       Originally:                          290
+       After changing UCP table:            187
+       After changing error message table:   43
+       After changing table of "verbs"       36
+       After changing table of Posix names   22
+     Thanks to the folks working on Gregex for glib for this insight.
+. --disable-stack-for-recursion caused compiling to fail unless -enable-
+     unicode-properties was also set.
+. Updated the tests so that they work when \R is defaulted to ANYCRLF.
+. Added checks for ANY and ANYCRLF to pcrecpp.cc where it previously
+     checked only for CRLF.
+. Added casts to pcretest.c to avoid compiler warnings.
+. Added Craig's patch to various pcrecpp modules to avoid compiler warnings.
+. Added Craig's patch to remove the WINDOWS_H tests, that were not working,
+     and instead check for _strtoi64 explicitly, and avoid the use of snprintf()
+     entirely. This removes changes made in 7 above.
+. The CMake files have been updated, and there is now more information about
+     building with CMake in the NON-UNIX-USE document.
+ Version 7.3 28-Aug-07
  ---------------------
 . In the rejigging of the build system that eventually resulted in 7.1, the
-Line 9 
 Version 7.3 05-Jul-07
+Line 203 
 Version 7.3 05-Jul-07
      brackets there is not right, since it causes compilers to look for an
      installed pcre.h, not the version that is in the source that is being
      compiled (which of course may be different). I have changed it back to:
        #include "pcre.h"
      I have a vague recollection that the change was concerned with compiling in
      different directories, but in the new build system, that is taken care of
      by the VPATH setting the Makefile.
 . The pattern .*$ when run in not-DOTALL UTF-8 mode with newline=any failed
      when the subject happened to end in the byte 0x85 (e.g. if the last
      character was \x{1ec5}). *Character* 0x85 is one of the "any" newline
-Line 23 
 Version 7.3 05-Jul-07
+Line 217 
 Version 7.3 05-Jul-07
      of another character. The bug was that, for an unlimited repeat of . in
      not-DOTALL UTF-8 mode, PCRE was advancing by bytes rather than by
      characters when looking for a newline.
-. A small performance improvement in the DOTALL UTF-8 mode .* case.
-. Debugging: adjusted the names of opcodes for different kinds of parentheses
-     in debug output.
-. Arrange to use "%I64d" instead of "%lld" for long printing in the pcrecpp
-     unittest when running under MinGW.
+. A small performance improvement in the DOTALL UTF-8 mode .* case.
+. Debugging: adjusted the names of opcodes for different kinds of parentheses
+     in debug output.
+. Arrange to use "%I64d" instead of "%lld" and "%I64u" instead of "%llu" for
+     long printing in the pcrecpp unittest when running under MinGW.
+. ESC_K was left out of the EBCDIC table.
+. Change 7.0/38 introduced a new limit on the number of nested non-capturing
+     parentheses; I made it 1000, which seemed large enough. Unfortunately, the
+     limit also applies to "virtual nesting" when a pattern is recursive, and in
+     this case 1000 isn't so big. I have been able to remove this limit at the
+     expense of backing off one optimization in certain circumstances. Normally,
+     when pcre_exec() would call its internal match() function recursively and
+     immediately return the result unconditionally, it uses a "tail recursion"
+     feature to save stack. However, when a subpattern that can match an empty
+     string has an unlimited repetition quantifier, it no longer makes this
+     optimization. That gives it a stack frame in which to save the data for
+     checking that an empty string has been matched. Previously this was taken
+     from the 1000-entry workspace that had been reserved. So now there is no
+     explicit limit, but more stack is used.
+. Applied Daniel's patches to solve problems with the import/export magic
+     syntax that is required for Windows, and which was going wrong for the
+     pcreposix and pcrecpp parts of the library. These were overlooked when this
+     problem was solved for the main library.
+. There were some crude static tests to avoid integer overflow when computing
+     the size of patterns that contain repeated groups with explicit upper
+     limits. As the maximum quantifier is 65535, the maximum group length was
+     set at 30,000 so that the product of these two numbers did not overflow a
+-bit integer. However, it turns out that people want to use groups that
+     are longer than 30,000 bytes (though not repeat them that many times).
+     Change 7.0/17 (the refactoring of the way the pattern size is computed) has
+     made it possible to implement the integer overflow checks in a much more
+     dynamic way, which I have now done. The artificial limitation on group
+     length has been removed - we now have only the limit on the total length of
+     the compiled pattern, which depends on the LINK_SIZE setting.
+. Fixed a bug in the documentation for get/copy named substring when
+     duplicate names are permitted. If none of the named substrings are set, the
+     functions return PCRE_ERROR_NOSUBSTRING (7); the doc said they returned an
+     empty string.
+. Because Perl interprets \Q...\E at a high level, and ignores orphan \E
+     instances, patterns such as [\Q\E] or [\E] or even [^\E] cause an error,
+     because the ] is interpreted as the first data character and the
+     terminating ] is not found. PCRE has been made compatible with Perl in this
+     regard. Previously, it interpreted [\Q\E] as an empty class, and [\E] could
+     cause memory overwriting.
+. Like Perl, PCRE automatically breaks an unlimited repeat after an empty
+     string has been matched (to stop an infinite loop). It was not recognizing
+     a conditional subpattern that could match an empty string if that
+     subpattern was within another subpattern. For example, it looped when
+     trying to match  (((?(1)X|))*)  but it was OK with  ((?(1)X|)*)  where the
+     condition was not nested. This bug has been fixed.
+. A pattern like \X?\d or \P{L}?\d in non-UTF-8 mode could cause a backtrack
+     past the start of the subject in the presence of bytes with the top bit
+     set, for example "\x8aBCD".
+. Added Perl 5.10 experimental backtracking controls (*FAIL), (*F), (*PRUNE),
+     (*SKIP), (*THEN), (*COMMIT), and (*ACCEPT).
+. Optimized (?!) to (*FAIL).
+. Updated the test for a valid UTF-8 string to conform to the later RFC 3629.
+     This restricts code points to be within the range 0 to 0x10FFFF, excluding
+     the "low surrogate" sequence 0xD800 to 0xDFFF. Previously, PCRE allowed the
+     full range 0 to 0x7FFFFFFF, as defined by RFC 2279. Internally, it still
+     does: it's just the validity check that is more restrictive.
+. Inserted checks for integer overflows during escape sequence (backslash)
+     processing, and also fixed erroneous offset values for syntax errors during
+     backslash processing.
+. Fixed another case of looking too far back in non-UTF-8 mode (cf 12 above)
+     for patterns like [\PPP\x8a]{1,}\x80 with the subject "A\x80".
+. An unterminated class in a pattern like (?1)\c[ with a "forward reference"
+     caused an overrun.
+. A pattern like (?:[\PPa*]*){8,} which had an "extended class" (one with
+     something other than just ASCII characters) inside a group that had an
+     unlimited repeat caused a loop at compile time (while checking to see
+     whether the group could match an empty string).
+. Debugging a pattern containing \p or \P could cause a crash. For example,
+     [\P{Any}] did so. (Error in the code for printing property names.)
+. An orphan \E inside a character class could cause a crash.
+. A repeated capturing bracket such as (A)? could cause a wild memory
+     reference during compilation.
+. There are several functions in pcre_compile() that scan along a compiled
+     expression for various reasons (e.g. to see if it's fixed length for look
+     behind). There were bugs in these functions when a repeated \p or \P was
+     present in the pattern. These operators have additional parameters compared
+     with \d, etc, and these were not being taken into account when moving along
+     the compiled data. Specifically:
+     (a) A item such as \p{Yi}{3} in a lookbehind was not treated as fixed
+         length.
+     (b) An item such as \pL+ within a repeated group could cause crashes or
+         loops.
+     (c) A pattern such as \p{Yi}+(\P{Yi}+)(?1) could give an incorrect
+         "reference to non-existent subpattern" error.
+     (d) A pattern like (\P{Yi}{2}\277)? could loop at compile time.
+. A repeated \S or \W in UTF-8 mode could give wrong answers when multibyte
+     characters were involved (for example /\S{2}/8g with "A\x{a3}BC").
+. Using pcregrep in multiline, inverted mode (-Mv) caused it to loop.
+. Patterns such as [\P{Yi}A] which include \p or \P and just one other
+     character were causing crashes (broken optimization).
+. Patterns such as (\P{Yi}*\277)* (group with possible zero repeat containing
+     \p or \P) caused a compile-time loop.
+. More problems have arisen in unanchored patterns when CRLF is a valid line
+     break. For example, the unstudied pattern [\r\n]A does not match the string
+     "\r\nA" because change 7.0/46 below moves the current point on by two
+     characters after failing to match at the start. However, the pattern \nA
+     *does* match, because it doesn't start till \n, and if [\r\n]A is studied,
+     the same is true. There doesn't seem any very clean way out of this, but
+     what I have chosen to do makes the common cases work: PCRE now takes note
+     of whether there can be an explicit match for \r or \n anywhere in the
+     pattern, and if so, 7.0/46 no longer applies. As part of this change,
+     there's a new PCRE_INFO_HASCRORLF option for finding out whether a compiled
+     pattern has explicit CR or LF references.
+. Added (*CR) etc for changing newline setting at start of pattern.
  Version 7.2 19-Jun-07

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