1 files changed, 83 insertions, 0 deletions
diff --git a/lib/libdvben50221/asn_1.c b/lib/libdvben50221/asn_1.c
new file mode 100644
index 0000000..803eb60
--- /dev/null
+++ b/lib/libdvben50221/asn_1.c
@@ -0,0 +1,83 @@
+/*
+	ASN.1 routines, implementation for libdvben50221
+	an implementation for the High Level Common Interface
+
+	Copyright (C) 2004, 2005 Manu Abraham <abraham.manu@gmail.com>
+	Copyright (C) 2006 Andrew de Quincey (adq_dvb@lidskialf.net)
+
+	This library is free software; you can redistribute it and/or modify
+	it under the terms of the GNU Lesser General Public License as
+	published by the Free Software Foundation; either version 2.1 of
+	the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Lesser General Public License for more details.
+
+	You should have received a copy of the GNU Lesser General Public
+	License along with this library; if not, write to the Free Software
+	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+*/
+
+#include <stdio.h>
+#include "asn_1.h"
+
+int asn_1_decode(uint16_t * length, uint8_t * asn_1_array,
+		 uint32_t asn_1_array_len)
+{
+	uint8_t length_field;
+
+	if (asn_1_array_len < 1)
+		return -1;
+	length_field = asn_1_array[0];
+
+	if (length_field < 0x80) {
+		// there is only one word
+		*length = length_field & 0x7f;
+		return 1;
+	} else if (length_field == 0x81) {
+		if (asn_1_array_len < 2)
+			return -1;
+
+		*length = asn_1_array[1];
+		return 2;
+	} else if (length_field == 0x82) {
+		if (asn_1_array_len < 3)
+			return -1;
+
+		*length = (asn_1_array[1] << 8) | asn_1_array[2];
+		return 3;
+	}
+
+	return -1;
+}
+
+int asn_1_encode(uint16_t length, uint8_t * asn_1_array,
+		 uint32_t asn_1_array_len)
+{
+	if (length < 0x80) {
+		if (asn_1_array_len < 1)
+			return -1;
+
+		asn_1_array[0] = length & 0x7f;
+		return 1;
+	} else if (length < 0x100) {
+		if (asn_1_array_len < 2)
+			return -1;
+
+		asn_1_array[0] = 0x81;
+		asn_1_array[1] = length;
+		return 2;
+	} else {
+		if (asn_1_array_len < 3)
+			return -1;
+
+		asn_1_array[0] = 0x82;
+		asn_1_array[1] = length >> 8;
+		asn_1_array[2] = length;
+		return 3;
+	}
+
+	// never reached
+}