grep branch, master, updated. v2.16-18-g5133396

[Jim Meyering]

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- Log -----------------------------------------------------------------
http://git.savannah.gnu.org/cgit/grep.git/commit/?id=5133396666c4e9bbe30cc1510e3ec703452d6a8b


commit 5133396666c4e9bbe30cc1510e3ec703452d6a8b
Author: Paolo Bonzini <address@hidden>
Date:   Mon Feb 17 15:18:10 2014 +0100

    revert "grep: DFA now uses rational ranges in unibyte locales"
    
    The correct course of action for grep is to defer range interpretation
    to regex, because otherwise you can get mismatches between regexes with
    backreferences and those without.
    
    For example, [A-Z]. will use RRI but ([A-Z])\1 won't, with the confusing
    result that the first regex won't match a superset of the language
    described by the second regex.
    
    The source of the confusion is that, even though grep's dfa.c was changed
    to use range checking instead of strcoll, that code is only invoked if
    dfaexec is called with backref = NULL, and that never happens for grep!
    
    In the end, all that's needed for RRI is compiling --with-included-regex,
    and in that case the patch is almost a no-op.  Almost, because there
    are corner cases that aren't handled correctly (e.g. [a-[.e.]], or
    regular expressions that include a NUL character), but this can be
    handled separately.
    
    * NEWS: Revert paragraph introduced by commit v2.16-7-g1078b64.
    * src/dfa.c (parse_bracket_exp): Revert back to regcomp/regexec.

diff --git a/NEWS b/NEWS
index 2ff7272..0130b90 100644
--- a/NEWS
+++ b/NEWS
@@ -10,15 +10,6 @@ GNU grep NEWS                                    -*- outline 
-*-
   grep (without -i) in a multibyte locale is now up to 7 times faster
   when processing many matched lines.
 
-  Range expressions in unibyte locales now ordinarily use the rational
-  range interpretation, in which [a-z] matches only lower-case ASCII
-  letters regardless of locale, and similarly for other ranges.  (This
-  was already true for multibyte locales.)  Portable programs should
-  continue to specify the C locale when using range expressions, since
-  these expressions have unspecified behavior in non-GNU systems and
-  are not yet guaranteed to use the rational range interpretation even
-  in GNU systems.
-
 ** Maintenance
 
   grep's --mmap option was disabled in March of 2010, and began to
diff --git a/src/dfa.c b/src/dfa.c
index f7453c7..a133e03 100644
--- a/src/dfa.c
+++ b/src/dfa.c
@@ -1106,14 +1106,30 @@ parse_bracket_exp (void)
             }
           else
             {
+              /* Defer to the system regex library about the meaning
+                 of range expressions.  */
+              regex_t re;
+              char pattern[6] = { '[', 0, '-', 0, ']', 0 };
+              char subject[2] = { 0, 0 };
               c1 = c;
               if (case_fold)
                 {
                   c1 = tolower (c1);
                   c2 = tolower (c2);
                 }
-              for (c = c1; c <= c2; c++)
-                setbit_case_fold_c (c, ccl);
+
+              pattern[1] = c1;
+              pattern[3] = c2;
+              regcomp (&re, pattern, REG_NOSUB);
+              for (c = 0; c < NOTCHAR; ++c)
+                {
+                  if ((case_fold && isupper (c)))
+                    continue;
+                  subject[0] = c;
+                  if (regexec (&re, subject, 0, NULL, 0) != REG_NOMATCH)
+                    setbit_case_fold_c (c, ccl);
+                }
+              regfree (&re);
             }
 
           colon_warning_state |= 8;

-----------------------------------------------------------------------

Summary of changes:
 NEWS      |    9 ---------
 src/dfa.c |   20 ++++++++++++++++++--
 2 files changed, 18 insertions(+), 11 deletions(-)


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