/*
 *  TS2sec - simple MPEG Transport stream to DVB sections convert
 *
 *  Copyright (C) 2009,2010 Ondrej Caletka <o.caletka@sh.cvut.cz>
 *  TEST PROJECT ONLY, PROBABLY DOES NOT WORK WELL
 *  USE AT YOUR OWN RISK, YOU HAVE BEEN WARNED
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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 (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#define _GNU_SOURCE

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif /* HAVE_CONFIG_H */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdint.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>

#define BUFLEN 1024


#define max(a,b) ((a)>(b) ? (a):(b))
#define min(a,b) ((a)<(b) ? (a):(b))

int main(int argc, char *argv[]) {

	int input_fd, output_fd;
	int pid_req = 18;
	int r;
	uint8_t buf[BUFLEN], *bhead=buf;
	int n=0;
	int pid_actual;
	
	uint8_t outbuf[1<<12], *outhead;
	int seclen, secleft;
	int first;
	uint8_t tscont;
    uint8_t secptr; //Pointer to section start


	input_fd = fileno(stdin);
	if (isatty(input_fd)) {
		fprintf(stderr, "Input should be redirected. Quitting.\n");
		exit(EXIT_FAILURE);
	}
	output_fd = fileno(stdout);
	if (isatty(output_fd)) {
		fprintf(stderr, "Output should be redirected. Not writing any data.\n");
		output_fd = open("/dev/null", O_WRONLY);
	}
	
	if (output_fd < 0) {
		fprintf(stderr, "Cannot open output file: %s\n",
				strerror(errno));
		exit(EXIT_FAILURE);
	}


	first=1;
	secleft=1;
	while(1) {
		//fprintf(stderr,"First: %d, seclen: %d, secleft: %d\n",first, seclen, secleft);
		if (secleft == 0) { //write the output
			outhead=outbuf;
			while (seclen>0) {
				r = write(output_fd, outhead, seclen);
				if (r<0) {
					fprintf(stderr, "Write failed: %s\n",
							strerror(errno));
					close(output_fd);
					exit(EXIT_FAILURE);
				}
				outhead+=r;
				seclen-=r;
			}
			secleft=first=1;
			//dprintf(1,"\xde\xad\xbe\xef");
			//tcdrain(1);
		}

		/* move remaining data to front of buffer */
		if (n>0) {
			memmove(buf, bhead, n);
		}

		if (n<sizeof(buf)) {
			r = read(input_fd, buf+n, sizeof(buf)-n);
			if (r < 0){
				fprintf(stderr,"read() failed: %s\n",
						strerror(errno));
				close(output_fd);
				exit(EXIT_FAILURE);
			}
			if (r == 0){
				close(output_fd);
				exit(EXIT_SUCCESS);
			}
			bhead=buf;
			n+=r;
		}

		while (*bhead != 0x47 && n>0) { /*SYNC BYTE*/
			bhead++;
			n--;
		}
		if (n<188) 
			continue;

		pid_actual = ((*(bhead+1) & 0x1F) << 8) | *(bhead+2);
		if (first || ((*(bhead+1) & 0x40) && pid_actual == pid_req)) {
			if (!(*(bhead+1) & 0x40) || pid_actual != pid_req) {
				n-=188;
				bhead += 188;
				continue;
			}
			tscont = *(bhead+3) & 0x0F; //continuity counter
			first=0;
            secptr = *(bhead+4);
            if (secptr > 182) {
                fprintf(stderr, "ERROR: Bad section pointer\n");
                exit(1);
            }
			seclen=secleft=3 + (((*(bhead+6+secptr) & 0x0F) << 8) | *(bhead+7+secptr));
			outhead=outbuf;

			r=min(183-secptr,secleft);
			memcpy(outhead, bhead+5+secptr, r);
			//fprintf(stderr,"Copyed %d bytes\n",r);
			secleft -= r;
			outhead += r;
			n-=188;
			bhead+=188;
			continue;
		} else {
			if ((*(bhead+3) & 0x0F) != (++tscont & 0x0F)) {
				secleft=first=1;
				n-=188;
				bhead+=188;
				continue;
			}
			if (pid_actual != pid_req) {
				n-=188;
				bhead += 188;
				continue;
			}
			r=min(184,secleft);
			memcpy(outhead, bhead+4, r);
			//fprintf(stderr,"Copyed %d bytes\n",r);
			secleft -= r;
			outhead += r;
			n-=188;
			bhead+=188;
			continue;
		}
	}

	return 0;
}