gawk: Wrong behavior in binary mode

[Carlos G.]

Hi... I think this is a bug.
When working with gawk in binary mode, the length() and index() built-ins
fail with character codes greater than 127(0x7f). For example:

$ printf "\x80\x81\x82\x83" | gawk 'BEGIN { BINMODE=1 } { print length }'
0

But it should print 4.
I've found that this happens because gawk assumes multi-byte in those cases.
The following patch worked fine for me:

--- builtin.old    2008-12-08 23:10:29.000000000 -0200
+++ gawk-3.1.6/builtin.c    2008-12-08 23:07:28.000000000 -0200
@@ -331,7 +331,7 @@
             if (l2 > l1)
                 break;
 #ifdef MBS_SUPPORT
-            if (gawk_mb_cur_max > 1) {
+            if (!BINMODE && gawk_mb_cur_max > 1) {
                 const wchar_t *pos;

                 s1 = force_wstring(s1);
@@ -370,7 +370,7 @@
                 break;
             }
 #ifdef MBS_SUPPORT
-            if (gawk_mb_cur_max > 1) {
+            if (!BINMODE && gawk_mb_cur_max > 1) {
                 const wchar_t *pos;

                 s1 = force_wstring(s1);
@@ -457,8 +457,9 @@
         if (do_lint && (tmp->flags & (STRING|STRCUR)) == 0)
             lintwarn(_("length: received non-string argument"));
         tmp = force_string(tmp);
+
 #ifdef MBS_SUPPORT
-        if (gawk_mb_cur_max > 1) {
+        if (!BINMODE && gawk_mb_cur_max > 1) {
             tmp = force_wstring(tmp);
             len = tmp->wstlen;
         } else