diff --git a/ChangeLog b/ChangeLog
index 0dcffeca7a..f27b805ff8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Nov  9 16:51:42 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* io.c (rb_io_each_byte): should update rbuf_off and rbuf_len for
+	  each iteration.  [ruby-dev:31659][ruby-dev:32192]
+
 Fri Nov  9 15:52:00 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* encoding.c (enc_check_encoding, rb_set_primary_encoding): ENCODING
diff --git a/io.c b/io.c
index ded34f07de..1754224af9 100644
--- a/io.c
+++ b/io.c
@@ -2022,11 +2022,11 @@ rb_io_each_byte(VALUE io)
 	p = fptr->rbuf+fptr->rbuf_off;
 	e = p + fptr->rbuf_len;
 	while (p < e) {
+	    fptr->rbuf_off++;
+	    fptr->rbuf_len--;
 	    rb_yield(INT2FIX(*p & 0xff));
 	    p++;
 	}
-	fptr->rbuf_off += fptr->rbuf_len;
-	fptr->rbuf_len = 0;
 	rb_io_check_readable(fptr);
 	READ_CHECK(fptr);
 	if (io_fillbuf(fptr) < 0) {