/*****************************************************************************
#                                                                            #
#    uStreamer - Lightweight and fast MJPEG-HTTP streamer.                   #
#                                                                            #
#    This source file is partially based on this code:                       #
#      - https://github.com/catid/kvm/blob/master/kvm_pipeline/src           #
#                                                                            #
#    Copyright (C) 2018-2024  Maxim Devaev <mdevaev@gmail.com>               #
#                                                                            #
#    This program is free software: you can redistribute it and/or modify    #
#    it under the terms of the GNU General Public License as published by    #
#    the Free Software Foundation, either version 3 of the License, or       #
#    (at your option) any later version.                                     #
#                                                                            #
#    This program is distributed in the hope that it will be useful,         #
#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
#    GNU General Public License for more details.                            #
#                                                                            #
#    You should have received a copy of the GNU General Public License       #
#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
#                                                                            #
*****************************************************************************/


#include "rtp.h"

#include <stdlib.h>

#include "uslibs/types.h"
#include "uslibs/tools.h"


us_rtp_s *us_rtp_init(void) {
	us_rtp_s *rtp;
	US_CALLOC(rtp, 1);
	return rtp;
}

void us_rtp_destroy(us_rtp_s *rtp) {
	free(rtp);
}

void us_rtp_assign(us_rtp_s *rtp, uint payload, bool video) {
	rtp->payload = payload;
	rtp->video = video;
	rtp->ssrc = us_triple_u32(us_get_now_monotonic_u64());
}

void us_rtp_write_header(us_rtp_s *rtp, u32 pts, bool marked) {
	u32 word0 = 0x80000000;
	if (marked) {
		word0 |= 1 << 23;
	}
	word0 |= (rtp->payload & 0x7F) << 16;
	word0 |= rtp->seq;
	++rtp->seq;

#	define WRITE_BE_U32(x_offset, x_value) \
		*((u32*)(rtp->datagram + x_offset)) = __builtin_bswap32(x_value)
	WRITE_BE_U32(0, word0);
	WRITE_BE_U32(4, pts);
	WRITE_BE_U32(8, rtp->ssrc);
#	undef WRITE_BE_U32
}