diff --git a/marshal.c b/marshal.c
index e05b9f5..c00ddd2 100644
--- a/marshal.c
+++ b/marshal.c
@@ -81,7 +81,7 @@ shortlen(long len, BDIGIT *ds)
 
 static ID s_dump, s_load, s_mdump, s_mload;
 static ID s_dump_data, s_load_data, s_alloc, s_call;
-static ID s_getbyte, s_read, s_write, s_binmode;
+static ID s_getbyte, s_read, s_readpartial, s_write, s_binmode;
 
 typedef struct {
     VALUE newclass;
@@ -958,7 +958,10 @@ marshal_dump(int argc, VALUE *argv)
 
 struct load_arg {
     VALUE src;
+    char *buf;
+    long buflen;
     long offset;
+    int partial;
     st_table *symbols;
     st_table *data;
     VALUE proc;
@@ -1030,15 +1033,29 @@ r_byte(struct load_arg *arg)
 	    c = (unsigned char)RSTRING_PTR(arg->src)[arg->offset++];
 	}
 	else {
+	  too_short:
 	    rb_raise(rb_eArgError, "marshal data too short");
 	}
     }
     else {
-	VALUE src = arg->src;
-	VALUE v = rb_funcall2(src, s_getbyte, 0, 0);
-	check_load_arg(arg, s_getbyte);
-	if (NIL_P(v)) rb_eof_error();
-	c = (unsigned char)NUM2CHR(v);
+	if (arg->buflen == 0) {
+	    VALUE str, n = LONG2NUM(BUFSIZ);
+
+	    if (arg->partial)
+		str = rb_funcall2(arg->src, s_readpartial, 1, &n);
+	    else
+		str = rb_funcall2(arg->src, s_read, 1, &n);
+
+	    check_load_arg(arg, s_read);
+	    if (NIL_P(str)) goto too_short;
+	    StringValue(str);
+	    arg->infection |= (int)FL_TEST(str, MARSHAL_INFECTION);
+	    memcpy(arg->buf, RSTRING_PTR(str), RSTRING_LEN(str));
+	    arg->offset = 0;
+	    arg->buflen = RSTRING_LEN(str);
+	}
+	c = (unsigned char)arg->buf[arg->offset++];
+	arg->buflen--;
     }
     return c;
 }
@@ -1091,6 +1108,74 @@ r_long(struct load_arg *arg)
     return x;
 }
 
+static VALUE
+r_bytes1(long len, struct load_arg *arg)
+{
+    VALUE str, n = LONG2NUM(len);
+
+    str = rb_funcall2(arg->src, s_read, 1, &n);
+    check_load_arg(arg, s_read);
+
+    if (NIL_P(str)) {
+      too_short:
+	rb_raise(rb_eArgError, "marshal data too short");
+    }
+    StringValue(str);
+    if (RSTRING_LEN(str) < len) goto too_short;
+
+    arg->infection |= (int)FL_TEST(str, MARSHAL_INFECTION);
+
+    return str;
+}
+
+static VALUE
+r_bytes1_partial(long len, struct load_arg *arg)
+{
+    long buflen = arg->buflen;
+    long tmp_len, need = len - buflen;
+    VALUE n = LONG2NUM(need > BUFSIZ ? need : BUFSIZ);
+    VALUE str, tmp;
+    const char *tmp_ptr;
+
+    tmp = rb_funcall2(arg->src, s_readpartial, 1, &n);
+
+    check_load_arg(arg, s_read);
+    if (NIL_P(tmp)) {
+      too_short:
+	rb_raise(rb_eArgError, "marshal data too short");
+    }
+    StringValue(tmp);
+
+    tmp_ptr = RSTRING_PTR(tmp);
+    tmp_len = RSTRING_LEN(tmp);
+
+    if (tmp_len < need) {
+	VALUE fill;
+
+	/* retry */
+	n = LONG2NUM(need-tmp_len);
+	fill = rb_funcall2(arg->src, s_read, 1, &n);
+
+	if (NIL_P(fill)) goto too_short;
+	StringValue(fill);
+	if (RSTRING_LEN(fill) < need-tmp_len) goto too_short;
+
+	rb_str_concat(tmp, fill);
+	tmp_len = RSTRING_LEN(tmp);
+    }
+
+    arg->infection |= (int)FL_TEST(tmp, MARSHAL_INFECTION);
+    str = rb_str_new(arg->buf+arg->offset, buflen);
+    rb_str_cat(str, tmp_ptr, need);
+    if (tmp_len-need > 0)
+	memcpy(arg->buf, tmp_ptr+need, tmp_len-need);
+
+    arg->offset = 0;
+    arg->buflen = tmp_len - need;
+
+    return str;
+}
+
 #define r_bytes(arg) r_bytes0(r_long(arg), (arg))
 
 static VALUE
@@ -1105,19 +1190,21 @@ r_bytes0(long len, struct load_arg *arg)
 	    arg->offset += len;
 	}
 	else {
-	  too_short:
 	    rb_raise(rb_eArgError, "marshal data too short");
 	}
     }
     else {
-	VALUE src = arg->src;
-	VALUE n = LONG2NUM(len);
-	str = rb_funcall2(src, s_read, 1, &n);
-	check_load_arg(arg, s_read);
-	if (NIL_P(str)) goto too_short;
-	StringValue(str);
-	if (RSTRING_LEN(str) != len) goto too_short;
-	arg->infection |= (int)FL_TEST(str, MARSHAL_INFECTION);
+	if (len <= arg->buflen) {
+	    str = rb_str_new(arg->buf+arg->offset, len);
+	    arg->offset += len;
+	    arg->buflen -= len;
+	}
+	else {
+	    if (arg->partial)
+		str = r_bytes1_partial(len, arg);
+	    else
+		str = r_bytes1(len, arg);
+	}
     }
     return str;
 }
@@ -1784,6 +1871,12 @@ marshal_load(int argc, VALUE *argv)
     arg->data    = st_init_numtable();
     arg->compat_tbl = st_init_numtable();
     arg->proc = 0;
+    arg->partial = 0;
+
+    if(NIL_P(v)) {
+	if (rb_respond_to(port, s_readpartial)) arg->partial = 1;
+	arg->buf = xmalloc(BUFSIZ);
+    }
 
     major = r_byte(arg);
     minor = r_byte(arg);
@@ -1921,6 +2014,7 @@ Init_marshal(void)
     s_call = rb_intern("call");
     s_getbyte = rb_intern("getbyte");
     s_read = rb_intern("read");
+    s_readpartial = rb_intern("readpartial");
     s_write = rb_intern("write");
     s_binmode = rb_intern("binmode");