/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * ASN.1 Basic Encoding Rules (DER)

 *

 * Copyright 2011 Samsung, Author Jiten Pathy

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *	 http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <winpr/crt.h>

#include <freerdp/crypto/der.h>

int _der_skip_length(int length)

{

	if (length > 0x7F && length <= 0xFF)

		return 2;

	else if (length > 0xFF)

		return 3;

	else

		return 1;

}

int der_write_length(wStream* s, int length)

{

	if (length > 0x7F && length <= 0xFF)

	{

		Stream_Write_UINT8(s, 0x81);

		Stream_Write_UINT8(s, length);

		return 2;

	}

	else if (length > 0xFF)

	{

		Stream_Write_UINT8(s, 0x82);

		Stream_Write_UINT16_BE(s, length);

		return 3;

	}

	else

	{

		Stream_Write_UINT8(s, length);

		return 1;

	}

}

int der_get_content_length(int length)

{

	if (length > 0x81 && length <= 0x102)

		return length - 3;

	else if (length > 0x102)

		return length - 4;

	else

		return length - 2;

}

int der_skip_contextual_tag(int length)

{

	return _der_skip_length(length) + 1;

}

int der_write_contextual_tag(wStream* s, BYTE tag, int length, BOOL pc)

{

	Stream_Write_UINT8(s, (ER_CLASS_CTXT | ER_PC(pc)) | (ER_TAG_MASK & tag));

	return der_write_length(s, length) + 1;

}

static void der_write_universal_tag(wStream* s, BYTE tag, BOOL pc)

{

	Stream_Write_UINT8(s, (ER_CLASS_UNIV | ER_PC(pc)) | (ER_TAG_MASK & tag));

}

int der_skip_octet_string(int length)

{

	return 1 + _der_skip_length(length) + length;

}

void der_write_octet_string(wStream* s, BYTE* oct_str, int length)

{

	der_write_universal_tag(s, ER_TAG_OCTET_STRING, FALSE);

	der_write_length(s, length);

	Stream_Write(s, oct_str, length);

}

int der_skip_sequence_tag(int length)

{

	return 1 + _der_skip_length(length);

}

int der_write_sequence_tag(wStream* s, int length)

{

	Stream_Write_UINT8(s, (ER_CLASS_UNIV | ER_CONSTRUCT) | (ER_TAG_MASK & ER_TAG_SEQUENCE));

	return der_write_length(s, length) + 1;

}