util.hpp

#ifndef INCLUDE_UTIL_HPP
#define INCLUDE_UTIL_HPP

#include <stddef.h>
#include <stdint.h>
#include <vector>

struct PSI
{
    int table_id;
    int section_length;
    int version_number;
    int current_next_indicator;
    int continuity_counter;
    int data_count;
    uint8_t data[1024];
};

struct PMT_REF
{
    int pmt_pid;
    int program_number;
};

struct PAT
{
    int transport_stream_id;
    int version_number;
    std::vector<PMT_REF> pmt;
    PSI psi;
};

uint16_t calc_crc16_ccitt(const uint8_t *data, int data_size, uint16_t crc = 0);
uint32_t calc_crc32(const uint8_t *data, int data_size, uint32_t crc = 0xffffffff);
int extract_psi(PSI *psi, const uint8_t *payload, int payload_size, int unit_start, int counter);
void extract_pat(PAT *pat, const uint8_t *payload, int payload_size, int unit_start, int counter);
int get_ts_payload_size(const uint8_t *packet);
int resync_ts(const uint8_t *data, int data_size, int *unit_size);

inline int extract_ts_header_unit_start(const uint8_t *packet) { return !!(packet[1] & 0x40); }
inline int extract_ts_header_pid(const uint8_t *packet) { return ((packet[1] & 0x1f) << 8) | packet[2]; }
inline int extract_ts_header_adaptation(const uint8_t *packet) { return (packet[3] >> 4) & 0x03; }
inline int extract_ts_header_counter(const uint8_t *packet) { return packet[3] & 0x0f; }

inline uint8_t extract_bit(const uint8_t *data, size_t pos)
{
    return (data[pos >> 3] >> (7 - (pos & 7))) & 1;
}

inline bool read_bool(const uint8_t *data, size_t &pos)
{
    return !!extract_bit(data, pos++);
}

inline int read_bits(const uint8_t *data, size_t &pos, int n)
{
    int r = 0;
    while (--n >= 0) {
        r |= extract_bit(data, pos++) << n;
    }
    return r;
}

#endif