/*
 * Copyright (c) 2004, Yannick Verschueren
 * Copyright (c) 2005, Hervé Drolon, FreeImage Team
 * Copyright (c) 2002-2005, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "opj_includes.h"

/*
 * Read the information contains in VBAS [JPP/JPT stream message header]
 * Store information (7 bits) in value
 *
 */
unsigned int jpt_read_VBAS_info(opj_cio_t *cio, unsigned int value) {
	unsigned char elmt;

	elmt = cio_read(cio, 1);
	while ((elmt >> 7) == 1) {
		value = (value << 7);
		value |= (elmt & 0x7f);
		elmt = cio_read(cio, 1);
	}
	value = (value << 7);
	value |= (elmt & 0x7f);

	return value;
}

/*
 * Initialize the value of the message header structure 
 *
 */
void jpt_init_msg_header(opj_jpt_msg_header_t * header) {
	header->Id = 0;		/* In-class Identifier    */
	header->last_byte = 0;	/* Last byte information  */
	header->Class_Id = 0;		/* Class Identifier       */
	header->CSn_Id = 0;		/* CSn : index identifier */
	header->Msg_offset = 0;	/* Message offset         */
	header->Msg_length = 0;	/* Message length         */
	header->Layer_nb = 0;		/* Auxiliary for JPP case */
}

/*
 * Re-initialize the value of the message header structure
 *
 * Only parameters always present in message header
 *
 */
void jpt_reinit_msg_header(opj_jpt_msg_header_t * header) {
	header->Id = 0;		/* In-class Identifier    */
	header->last_byte = 0;	/* Last byte information  */
	header->Msg_offset = 0;	/* Message offset         */
	header->Msg_length = 0;	/* Message length         */
}

/*
 * Read the message header for a JPP/JPT - stream
 *
 */
void jpt_read_msg_header(opj_common_ptr cinfo, opj_cio_t *cio, opj_jpt_msg_header_t *header) {
	unsigned char elmt, Class = 0, CSn = 0;
	jpt_reinit_msg_header(header);

	/* ------------- */
	/* VBAS : Bin-ID */
	/* ------------- */
	elmt = cio_read(cio, 1);

	/* See for Class and CSn */
	switch ((elmt >> 5) & 0x03) {
		case 0:
			opj_event_msg(cinfo, EVT_ERROR, "Forbidden value encounter in message header !!\n");
			break;
		case 1:
			Class = 0;
			CSn = 0;
			break;
		case 2:
			Class = 1;
			CSn = 0;
			break;
		case 3:
			Class = 1;
			CSn = 1;
			break;
		default:
			break;
	}

	/* see information on bits 'c' [p 10 : A.2.1 general, ISO/IEC FCD 15444-9] */
	if (((elmt >> 4) & 0x01) == 1)
		header->last_byte = 1;

	/* In-class identifier */
	header->Id |= (elmt & 0x0f);
	if ((elmt >> 7) == 1)
		header->Id = jpt_read_VBAS_info(cio, header->Id);

	/* ------------ */
	/* VBAS : Class */
	/* ------------ */
	if (Class == 1) {
		header->Class_Id = 0;
		header->Class_Id = jpt_read_VBAS_info(cio, header->Class_Id);
	}

	/* ---------- */
	/* VBAS : CSn */
	/* ---------- */
	if (CSn == 1) {
		header->CSn_Id = 0;
		header->CSn_Id = jpt_read_VBAS_info(cio, header->CSn_Id);
	}

	/* ----------------- */
	/* VBAS : Msg_offset */
	/* ----------------- */
	header->Msg_offset = jpt_read_VBAS_info(cio, header->Msg_offset);

	/* ----------------- */
	/* VBAS : Msg_length */
	/* ----------------- */
	header->Msg_length = jpt_read_VBAS_info(cio, header->Msg_length);

	/* ---------- */
	/* VBAS : Aux */
	/* ---------- */
	if ((header->Class_Id & 0x01) == 1) {
		header->Layer_nb = 0;
		header->Layer_nb = jpt_read_VBAS_info(cio, header->Layer_nb);
	}
}
