diff -r 4508da679ffb -r 778388400f7b bfile_heuristics.c
--- a/bfile_heuristics.c	Thu Oct 20 17:29:23 2011 +0200
+++ b/bfile_heuristics.c	Fri Oct 21 15:09:26 2011 +0200
@@ -32,20 +32,23 @@
       def->bcount++;
     }
 
-    switch (def->level) {
-    case BFILE_LOW_ACCURACY:
-      if (def->tcount > 15 || next_char == EOF) {
-        ret = (1.0*def->bcount)/def->tcount > 0.32;
-      }
-      break;
-    case BFILE_HIGH_ACCURACY:
-      if (def->tcount > 500 || next_char == EOF) {
-        ret = (1.0*def->bcount)/def->tcount > 0.1;
-      }
-      break;
-    default: /* BFILE_MEDIUM_ACCURACY */
-      if (def->tcount > 100 || next_char == EOF) {
-        ret = (1.0*def->bcount)/def->tcount > 0.1;
+    if (def->tcount > 1) { /* empty files are text files */
+      switch (def->level) {
+      case BFILE_LOW_ACCURACY:
+        if (def->tcount > 15 || next_char == EOF) {
+          ret = (1.0*def->bcount)/def->tcount > 0.32;
+        }
+        break;
+      case BFILE_HIGH_ACCURACY:
+        if (def->tcount > 500 || next_char == EOF) {
+          ret = (1.0*def->bcount)/def->tcount > 0.1;
+        }
+        break;
+      default: /* BFILE_MEDIUM_ACCURACY */
+        if (def->tcount > 100 || next_char == EOF) {
+          ret = (1.0*def->bcount)/def->tcount > 0.1;
+        }
+        break;
       }
     }
   }