bb11441 - fixing edge case revealed by unit testing

libclamav/htmlnorm.c

@@ -584,9 +584,11 @@ static void screnc_decode(unsigned char *ptr, struct screnc_state *s)
 		} else {
 			*dst++ = *ptr++;
 			*dst++ = *ptr;
-			if (!*ptr)
+			if (!*ptr) {
+				dst--;
 				break;
 			}
+		}
 		ptr++;
 		s->length--;
 	}
@@ -618,7 +620,7 @@ static void screnc_decode(unsigned char *ptr, struct screnc_state *s)
 		remaining = strlen((const char*)ptr) + 1;
 		memmove(dst, ptr, remaining);
 	} else {
-		*ptr = '\0';
+		*dst = '\0';
 	}
 }