/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * ASN.1 Encoding Rules (BER/DER common functions)

 *

 * Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 * Modified by 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/er.h>

#include <freerdp/crypto/ber.h>

#include <freerdp/crypto/der.h>

void er_read_length(wStream* s, int* length)

{

	BYTE byte;

	Stream_Read_UINT8(s, byte);

	if (!length)

		return;

	*length = 0;

	if (!s)

		return;

	if (byte & 0x80)

	{

		byte &= ~(0x80);

		if (byte == 1)

			Stream_Read_UINT8(s, *length);

		if (byte == 2)

			Stream_Read_UINT16_BE(s, *length);

	}

	else

	{

		*length = byte;

	}

}

/**

 * Write er length.

 * @param s stream

 * @param length length

 */

int er_write_length(wStream* s, int length, BOOL flag)

{

	if (flag)

		return der_write_length(s, length);

	else

		return ber_write_length(s, length);

}

int _er_skip_length(int length)

{

	if (length > 0x7F)

		return 3;

	else

		return 1;

}

int er_get_content_length(int length)

{

	if (length - 1 > 0x7F)

		return length - 4;

	else

		return length - 2;

}

/**

 * Read er Universal tag.

 * @param s stream

 * @param tag er universally-defined tag

 * @return

 */

BOOL er_read_universal_tag(wStream* s, BYTE tag, BOOL pc)

{

	BYTE byte;

	Stream_Read_UINT8(s, byte);

	if (byte != (ER_CLASS_UNIV | ER_PC(pc) | (ER_TAG_MASK & tag)))

		return FALSE;

	return TRUE;

}

/**

 * Write er Universal tag.

 * @param s stream

 * @param tag er universally-defined tag

 * @param pc primitive (FALSE) or constructed (TRUE)

 */

void er_write_universal_tag(wStream* s, BYTE tag, BOOL pc)

{

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

}

/**

 * Read er Application tag.

 * @param s stream

 * @param tag er application-defined tag

 * @param length length

 */

BOOL er_read_application_tag(wStream* s, BYTE tag, int* length)

{

	BYTE byte;

	if (tag > 30)

	{

		Stream_Read_UINT8(s, byte);

		if (byte != ((ER_CLASS_APPL | ER_CONSTRUCT) | ER_TAG_MASK))

			return FALSE;

		Stream_Read_UINT8(s, byte);

		if (byte != tag)

			return FALSE;

		er_read_length(s, length);

	}

	else

	{

		Stream_Read_UINT8(s, byte);

		if (byte != ((ER_CLASS_APPL | ER_CONSTRUCT) | (ER_TAG_MASK & tag)))

			return FALSE;

		er_read_length(s, length);

	}

	return TRUE;

}

/**

 * Write er Application tag.

 * @param s stream

 * @param tag er application-defined tag

 * @param length length

 */

void er_write_application_tag(wStream* s, BYTE tag, int length, BOOL flag)

{

	if (tag > 30)

	{

		Stream_Write_UINT8(s, (ER_CLASS_APPL | ER_CONSTRUCT) | ER_TAG_MASK);

		Stream_Write_UINT8(s, tag);

		er_write_length(s, length, flag);

	}

	else

	{

		Stream_Write_UINT8(s, (ER_CLASS_APPL | ER_CONSTRUCT) | (ER_TAG_MASK & tag));

		er_write_length(s, length, flag);

	}

}

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

{

	BYTE byte;

	Stream_Read_UINT8(s, byte);

	if (byte != ((ER_CLASS_CTXT | ER_PC(pc)) | (ER_TAG_MASK & tag)))

	{

		Stream_Rewind(s, 1);

		return FALSE;

	}

	er_read_length(s, length);

	return TRUE;

}

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

{

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

	return er_write_length(s, length, flag) + 1;

}

int er_skip_contextual_tag(int length)

{

	return _er_skip_length(length) + 1;

}

BOOL er_read_sequence_tag(wStream* s, int* length)

{

	BYTE byte;

	Stream_Read_UINT8(s, byte);

	if (byte != ((ER_CLASS_UNIV | ER_CONSTRUCT) | (ER_TAG_SEQUENCE_OF)))

		return FALSE;

	er_read_length(s, length);

	return TRUE;

}

/**

 * Write er SEQUENCE tag.

 * @param s stream

 * @param length length

 */

int er_write_sequence_tag(wStream* s, int length, BOOL flag)

{

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

	return er_write_length(s, length, flag) + 1;

}

int er_skip_sequence(int length)

{

	return 1 + _er_skip_length(length) + length;

}

int er_skip_sequence_tag(int length)

{

	return 1 + _er_skip_length(length);

}

BOOL er_read_enumerated(wStream* s, BYTE* enumerated, BYTE count)

{

	int length = 0;

	er_read_universal_tag(s, ER_TAG_ENUMERATED, FALSE);

	er_read_length(s, &length);

	if (length == 1)

		Stream_Read_UINT8(s, *enumerated);

	else

		return FALSE;

	/* check that enumerated value falls within expected range */

	if (*enumerated + 1 > count)

		return FALSE;

	return TRUE;

}

void er_write_enumerated(wStream* s, BYTE enumerated, BYTE count, BOOL flag)

{

	er_write_universal_tag(s, ER_TAG_ENUMERATED, FALSE);

	er_write_length(s, 1, flag);

	Stream_Write_UINT8(s, enumerated);

}

BOOL er_read_bit_string(wStream* s, int* length, BYTE* padding)

{

	er_read_universal_tag(s, ER_TAG_BIT_STRING, FALSE);

	er_read_length(s, length);

	Stream_Read_UINT8(s, *padding);

	return TRUE;

}

BOOL er_write_bit_string_tag(wStream* s, UINT32 length, BYTE padding, BOOL flag)

{

	er_write_universal_tag(s, ER_TAG_BIT_STRING, FALSE);

	er_write_length(s, length, flag);

	Stream_Write_UINT8(s, padding);

	return TRUE;

}

BOOL er_read_octet_string(wStream* s, int* length)

{

	if (!er_read_universal_tag(s, ER_TAG_OCTET_STRING, FALSE))

		return FALSE;

	er_read_length(s, length);

	return TRUE;

}

/**

 * Write a er OCTET_STRING

 * @param s stream

 * @param oct_str octet string

 * @param length string length

 */

void er_write_octet_string(wStream* s, BYTE* oct_str, int length, BOOL flag)

{

	er_write_universal_tag(s, ER_TAG_OCTET_STRING, FALSE);

	er_write_length(s, length, flag);

	Stream_Write(s, oct_str, length);

}

int er_write_octet_string_tag(wStream* s, int length, BOOL flag)

{

	er_write_universal_tag(s, ER_TAG_OCTET_STRING, FALSE);

	er_write_length(s, length, flag);

	return 1 + _er_skip_length(length);

}

int er_skip_octet_string(int length)

{

	return 1 + _er_skip_length(length) + length;

}

/**

 * Read a er BOOLEAN

 * @param s

 * @param value

 */

BOOL er_read_BOOL(wStream* s, BOOL* value)

{

	int length = 0;

	BYTE v;

	if (!er_read_universal_tag(s, ER_TAG_BOOLEAN, FALSE))

		return FALSE;

	er_read_length(s, &length);

	if (length != 1)

		return FALSE;

	Stream_Read_UINT8(s, v);

	*value = (v ? TRUE : FALSE);

	return TRUE;

}

/**

 * Write a er BOOLEAN

 * @param s

 * @param value

 */

void er_write_BOOL(wStream* s, BOOL value)

{

	er_write_universal_tag(s, ER_TAG_BOOLEAN, FALSE);

	er_write_length(s, 1, FALSE);

	Stream_Write_UINT8(s, (value == TRUE) ? 0xFF : 0);

}

BOOL er_read_integer(wStream* s, UINT32* value)

{

	int length = 0;

	er_read_universal_tag(s, ER_TAG_INTEGER, FALSE);

	er_read_length(s, &length);

	if (value == NULL)

	{

		Stream_Seek(s, length);

		return TRUE;

	}

	if (length == 1)

	{

		Stream_Read_UINT8(s, *value);

	}

	else if (length == 2)

	{

		Stream_Read_UINT16_BE(s, *value);

	}

	else if (length == 3)

	{

		BYTE byte;

		Stream_Read_UINT8(s, byte);

		Stream_Read_UINT16_BE(s, *value);

		*value += (byte << 16);

	}

	else if (length == 4)

	{

		Stream_Read_UINT32_BE(s, *value);

	}

	else

	{

		return FALSE;

	}

	return TRUE;

}

/**

 * Write a er INTEGER

 * @param s

 * @param value

 */

int er_write_integer(wStream* s, INT32 value)

{

	er_write_universal_tag(s, ER_TAG_INTEGER, FALSE);

	if (value <= 127 && value >= -128)

	{

		er_write_length(s, 1, FALSE);

		Stream_Write_UINT8(s, value);

		return 2;

	}

	else if (value <= 32767 && value >= -32768)

	{

		er_write_length(s, 2, FALSE);

		Stream_Write_UINT16_BE(s, value);

		return 3;

	}

	else

	{

		er_write_length(s, 4, FALSE);

		Stream_Write_UINT32_BE(s, value);

		return 5;

	}

	return 0;

}

int er_skip_integer(INT32 value)

{

	if (value <= 127 && value >= -128)

	{

		return _er_skip_length(1) + 2;

	}

	else if (value <= 32767 && value >= -32768)

	{

		return _er_skip_length(2) + 3;

	}

	else

	{

		return _er_skip_length(4) + 5;

	}

	return 0;

}

BOOL er_read_integer_length(wStream* s, int* length)

{

	er_read_universal_tag(s, ER_TAG_INTEGER, FALSE);

	er_read_length(s, length);

	return TRUE;

}