/*****************************************************************************
 * sit.h: ISO/IEC 13818-1 Selection Information Table (SIT)
 *****************************************************************************
 * Copyright (C) 2009-2010 VideoLAN
 *
 * Authors: Christophe Massiot <massiot@via.ecp.fr>
 *          Georgi Chorbadzhiyski <georgi@unixsol.org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject
 * to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *****************************************************************************/

/*
 * Normative references:
 *  - ETSI EN 300 468 V1.11.1 (2010-04) (SI in DVB systems)
 */

#ifndef __BITSTREAM_DVB_SIT_H__
#define __BITSTREAM_DVB_SIT_H__

#include <bitstream/common.h>
#include <bitstream/mpeg/psi/psi.h>
#include <bitstream/mpeg/psi/descriptors.h>

#ifdef __cplusplus
extern "C"
{
#endif

/*****************************************************************************
 * Selection Information Table
 *****************************************************************************/
#define SIT_PID                 0x1f
#define SIT_TABLE_ID            0x7f
#define SIT_HEADER_SIZE         (PSI_HEADER_SIZE_SYNTAX1 + 2)
#define SIT_SERVICE_SIZE        4

static inline void sit_init(uint8_t *p_sit)
{
    psi_init(p_sit, true);
    psi_set_tableid(p_sit, SIT_TABLE_ID);
    p_sit[1] |= 0xe0;
    psi_set_tableidext(p_sit, 0xffff);
    psi_set_section(p_sit, 0);
    psi_set_lastsection(p_sit, 0);
}

static inline void sit_set_length(uint8_t *p_sit, uint16_t i_sit_length)
{
    psi_set_length(p_sit, SIT_HEADER_SIZE + PSI_CRC_SIZE - PSI_HEADER_SIZE
                    + i_sit_length);
}

static inline uint16_t sit_get_desclength(const uint8_t *p_sit)
{
    return ((p_sit[8] & 0x0f) << 8) | p_sit[9];
}

static inline void sit_set_desclength(uint8_t *p_sit, uint16_t i_length)
{
    p_sit[8] = ((i_length >> 8) & 0xff) | 0xf0;
    p_sit[9] =  i_length        & 0xff;
}

static inline uint8_t *sit_get_descs(uint8_t *p_sit)
{
    return &p_sit[8];
}

static inline void sitn_init(uint8_t *p_sit_n)
{
    p_sit_n[2] = 0x80;
}

static inline uint16_t sitn_get_sid(const uint8_t *p_sit_n)
{
    return (p_sit_n[0] << 8) | p_sit_n[1];
}

static inline void sitn_set_sid(uint8_t *p_sit_n, uint16_t i_sid)
{
    p_sit_n[0] = (i_sid >> 8) & 0xff;
    p_sit_n[1] =  i_sid       & 0xff;
}

static inline uint8_t sitn_get_running(const uint8_t *p_sit_n)
{
    return (p_sit_n[2] & 0x70) >> 4;
}

static inline void sitn_set_running(uint8_t *p_sit_n, uint8_t i_running_status)
{
    p_sit_n[2] = (p_sit_n[2] &~ 0x70) | ((i_running_status & 0x07) << 4);
}

static inline void sitn_set_desclength(uint8_t *p_sit_n, uint16_t i_length)
{
    p_sit_n[2] = ((i_length >> 8) & 0xff) | (p_sit_n[2] & 0xf0);
    p_sit_n[3] =  i_length        & 0xff;
}

static inline uint16_t sitn_get_desclength(const uint8_t *p_sit_n)
{
    return ((p_sit_n[2] & 0xf) << 8) | p_sit_n[3];
}

static inline uint8_t *sitn_get_descs(uint8_t *p_sit_n)
{
    return &p_sit_n[2];
}

static inline uint8_t *sit_get_service(uint8_t *p_sit, uint8_t n)
{
    uint16_t i_section_size = psi_get_length(p_sit) + PSI_HEADER_SIZE
                               - PSI_CRC_SIZE;
    uint8_t *p_sit_n = p_sit + SIT_HEADER_SIZE + sit_get_desclength(p_sit);
    if (p_sit_n - p_sit > i_section_size) return NULL;

    while (n) {
        if (p_sit_n + SIT_SERVICE_SIZE - p_sit > i_section_size) return NULL;
        p_sit_n += SIT_SERVICE_SIZE + sitn_get_desclength(p_sit_n);
        n--;
    }
    if (p_sit_n - p_sit >= i_section_size) return NULL;
    return p_sit_n;
}

static inline bool sit_validate_service(const uint8_t *p_sit, const uint8_t *p_sit_n,
                                   uint16_t i_desclength)
{
    uint16_t i_section_size = psi_get_length(p_sit) + PSI_HEADER_SIZE
                               - PSI_CRC_SIZE;
    return (p_sit_n + SIT_SERVICE_SIZE + i_desclength
             <= p_sit + i_section_size);
}

static inline bool sit_validate(const uint8_t *p_sit)
{
    uint16_t i_section_size = psi_get_length(p_sit) + PSI_HEADER_SIZE
                               - PSI_CRC_SIZE;
    const uint8_t *p_sit_n;

    if (!psi_get_syntax(p_sit) || psi_get_section(p_sit)
         || psi_get_lastsection(p_sit)
         || psi_get_tableid(p_sit) != SIT_TABLE_ID)
        return false;

    if (!psi_check_crc(p_sit))
        return false;

    if (i_section_size < SIT_HEADER_SIZE
         || i_section_size < SIT_HEADER_SIZE + sit_get_desclength(p_sit))
        return false;

    if (!descs_validate(sit_get_descs((uint8_t *)p_sit)))
        return false;

    p_sit_n = p_sit + SIT_HEADER_SIZE + sit_get_desclength(p_sit);

    while (p_sit_n + SIT_SERVICE_SIZE - p_sit <= i_section_size
            && p_sit_n + SIT_SERVICE_SIZE + sitn_get_desclength(p_sit_n) - p_sit
                <= i_section_size) {
        if (!descs_validate(sitn_get_descs((uint8_t *)p_sit_n)))
            return false;

        p_sit_n += SIT_SERVICE_SIZE + sitn_get_desclength(p_sit_n);
    }

    return (p_sit_n - p_sit == i_section_size);
}

#ifdef __cplusplus
}
#endif

#endif