diff --git a/ChangeLog b/ChangeLog
index b29f805a45..3fb2ee29b1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+Mon Nov 16 07:59:38 2009  wanabe  <s.wanabe@gmail.com>
+
+	* io.c (read_all): don't call io_shift_cbuf until bufffering enough or
+	  econv_finished.   [ruby-dev:39696]
+
+	* io.c (more_char): don't call clear_readconv to read buffer after
+	  econv_finished.
+
+	* io.c (appendline, rb_io_each_codepoint): clear readconv when done.
+
 Mon Nov 16 01:58:08 2009  Yusuke Endoh  <mame@tsg.ne.jp>
 
 	* include/ruby/ruby.h (rb_classext_t): annotate @internal.
diff --git a/io.c b/io.c
index 39ef165f07..5479b9c0f0 100644
--- a/io.c
+++ b/io.c
@@ -1625,7 +1625,6 @@ more_char(rb_io_t *fptr)
             return 0;
 
         if (res == econv_finished) {
-	    clear_readconv(fptr);
             return -1;
 	}
 
@@ -1687,10 +1686,14 @@ read_all(rb_io_t *fptr, long siz, VALUE str)
         else rb_str_set_len(str, 0);
         make_readconv(fptr, 0);
         while (1) {
-            if (fptr->cbuf_len) {
+            if (fptr->cbuf_len > fptr->cbuf_capa / 2) {
                 io_shift_cbuf(fptr, fptr->cbuf_len, &str);
             }
             if (more_char(fptr) == -1) {
+		if (fptr->cbuf_len) {
+		    io_shift_cbuf(fptr, fptr->cbuf_len, &str);
+		}
+		clear_readconv(fptr);
                 return io_enc_str(str, fptr);
             }
         }
@@ -2172,6 +2175,7 @@ appendline(rb_io_t *fptr, int delim, VALUE *strp, long *lp)
                 }
             }
         } while (more_char(fptr) != -1);
+        clear_readconv(fptr);
         *lp = limit;
         return EOF;
     }
@@ -2820,6 +2824,7 @@ rb_io_each_codepoint(VALUE io)
 		    }
 		}
 		if (more_char(fptr) == -1) {
+		    clear_readconv(fptr);
 		    /* ignore an incomplete character before EOF */
 		    return io;
 		}