diff --git a/ChangeLog b/ChangeLog
index 1e18edac8c..200ae1ee14 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Feb 28 20:51:32 2007  URABE Shyouhei  <shyouhei@ruby-lang.org>
+
+	* pack.c (pack_unpack): properly ignore non-base64 octets such as
+	  UTF-8 encoded BOMs; submitted by SOUMA Yutaka <holon@radastery.jp>
+	  to fix [ruby-core:10437]
+
 Wed Feb 28 18:31:51 2007  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* ext/openssl/extconf.rb: no need to check unistd.h and sys/time.h.
diff --git a/pack.c b/pack.c
index fd0fbd6ac9..6dd4c1597b 100644
--- a/pack.c
+++ b/pack.c
@@ -1794,20 +1794,27 @@ pack_unpack(VALUE str, VALUE fmt)
 		    }
 		}
 		while (s < send) {
-		    while (s[0] == '\r' || s[0] == '\n') { s++; }
-		    if ((a = b64_xtable[(int)s[0]]) == -1) break;
-		    if ((b = b64_xtable[(int)s[1]]) == -1) break;
-		    if ((c = b64_xtable[(int)s[2]]) == -1) break;
-		    if ((d = b64_xtable[(int)s[3]]) == -1) break;
+		    a = b = c = d = -1;
+		    while((a = b64_xtable[(int)(*(unsigned char*)s)]) == -1 && s < send) { s++; }
+		    if( s >= send ) break;
+		    s++;
+		    while((b = b64_xtable[(int)(*(unsigned char*)s)]) == -1 && s < send) { s++; }
+		    if( s >= send ) break;
+		    s++;
+		    while((c = b64_xtable[(int)(*(unsigned char*)s)]) == -1 && s < send) { if( *s == '=' ) break; s++; }
+		    if( *s == '=' || s >= send ) break;
+		    s++;
+		    while((d = b64_xtable[(int)(*(unsigned char*)s)]) == -1 && s < send) { if( *s == '=' ) break; s++; }
+		    if( *s == '=' || s >= send ) break;
+		    s++;
 		    *ptr++ = a << 2 | b >> 4;
 		    *ptr++ = b << 4 | c >> 2;
 		    *ptr++ = c << 6 | d;
-		    s += 4;
 		}
 		if (a != -1 && b != -1) {
-		    if (s + 2 < send && s[2] == '=')
+		    if (c == -1 && *s == '=')
 			*ptr++ = a << 2 | b >> 4;
-		    if (c != -1 && s + 3 < send && s[3] == '=') {
+		    else if (c != -1 && *s == '=') {
 			*ptr++ = a << 2 | b >> 4;
 			*ptr++ = b << 4 | c >> 2;
 		    }