fix bug in (case)

reducing use of strlen

llt/dump.c

@@ -12,30 +12,27 @@ static char hexdig[] = "0123456789abcdef";
 void hexdump(ios_t *dest, char *buffer, size_t len, size_t startoffs)
 {
     size_t offs=0;
-    size_t i, pos, nc;
+    size_t i, pos;
     char ch, linebuffer[16];
     char hexc[4];
+    static char *spc50 = "                                                  ";
 
     hexc[2] = hexc[3] = ' ';
     do {
         ios_printf(dest, "%.8x  ", offs+startoffs);
         pos = 10;
-        for(i=0; i < 16 && (offs+i) < len; i++) {
-            ch = buffer[offs + i];
+        for(i=0; i < 16 && offs < len; i++, offs++) {
+            ch = buffer[offs];
             linebuffer[i] = (ch<32 || ch>=0x7f) ? '.' : ch;
             hexc[0] = hexdig[((unsigned char)ch)>>4];
             hexc[1] = hexdig[ch&0x0f];
-            nc = (i==7 || i==15) ? 4 : 3;
-            ios_write(dest, hexc, nc);
-            pos += nc;
+            pos += ios_write(dest, hexc, (i==7 || i==15) ? 4 : 3);
         }
         for(; i < 16; i++)
             linebuffer[i] = ' ';
-        for(i=0; i < 60-pos; i++)
-            ios_putc(' ', dest);
+        ios_write(dest, spc50, 60-pos);
         ios_putc('|', dest);
         ios_write(dest, linebuffer, 16);
         ios_write(dest, "|\n", 2);
-        offs += 16;
     } while (offs < len);
 }