grep: simplify and fix problems with KWset-DFA agreement patch

* src/dfa.c (dfambcache, parse_bracket_exp): Simplify.
(mbs_to_wchar, wctok, FETCH_WC, match_anychar, match_mb_charset)
(check_matching_with_multibyte_ops, transit_state_consume_1char)
(transit_state, dfaexec): Use wint_t, not wchar_t, so that
WEOF is treated correctly on platforms where WEOF is not a valid
wchar_t value.
(ctok, lex): Use int, not unsigned int, for characters,
so that EOF is treated more naturally.
(parse_bracket_exp): Use NOTCHAR to mark uninitialized char, since
FETCH_WC can now set the char to EOF.
(lex): Remove unnecessary test for EOF.
(parse_bracket_exp, atom): Swap then and else parts, to put
the small one first; this is more readable here.
* src/searchutils.c (is_mb_middle): Simplify.

1 files changed, 4 insertions, 8 deletions

diff --git a/src/searchutils.c b/src/searchutils.c
index 3c78f31c..76005bfc 100644
--- a/src/searchutils.c
+++ b/src/searchutils.c
@@ -249,10 +249,10 @@ is_mb_middle (const char **good, const char *buf, const char *end,
       if (mbclen == (size_t) -2)
         mbclen = mbrlen (p, end - p, &cur_state);
 
-      if (mbclen == (size_t) -1 || mbclen == (size_t) -2 || mbclen == 0)
+      if (! (0 < mbclen && mbclen < (size_t) -2))
         {
-          /* An invalid sequence, or a truncated multibyte character.
-             We treat it as a single byte character.  */
+          /* An invalid sequence, or a truncated multibyte character, or
+             a null wide character.  Treat it as a single byte character.  */
           mbclen = 1;
           memset (&cur_state, 0, sizeof cur_state);
         }
@@ -261,9 +261,5 @@ is_mb_middle (const char **good, const char *buf, const char *end,
 
   *good = p;
 
-  if (p > buf)
-    return true;
-
-  /* P == BUF here.  */
-  return false;
+  return buf < p;
 }