#!/usr/local/bin/perl

# This script takes RAW one-seg TS without PAT as input
# , and outputs TS with PAT generated with the information
# in the TS
#
# usage  cat input.ts|perl generatePAT.pl > output.ts
#

use strict;
# use String::CRC32;

binmode STDIN;
binmode STDOUT;

my $OneSegPMT_PID=0x1fc8;
my $NIT_PID=0x0010;
my $SDT_PID=0x0011;

my $PacketSize = 188;
my $program_number = 0;
my $transport_stream_id = 0;
my $section='';
my $continuity_counter=16;

for(;;){
	my $buf;
	my $len=read(STDIN,$buf,$PacketSize);
	last unless $len >0;

	my $pid=hex(unpack("H*", substr($buf,1,2)))&0x1FFF;

	if($pid==$OneSegPMT_PID){
	# PMT
		$program_number = hex(unpack("H*", substr($buf,8,2)))&0xFFFF;
	}elsif($pid==$SDT_PID){
    # SDT
		$transport_stream_id = hex(unpack("H*", substr($buf,8,2)))&0xFFFF;
		
		#insert PAT
		if($program_number != 0){
			$buf .= &generatePAT($program_number,$transport_stream_id);
		}
    }
	$len=print STDOUT $buf;
}

sub generatePAT{
	my ($program_number, $transport_stream_id) = @_;
	my $buf;

#	print STDERR "program_number = $program_number\n";
#	print STDERR "transport_stream_id = $transport_stream_id\n";
	if($section eq ''){
		print STDERR "generating section\n";
		$section .= pack("H*","00b011");
		$section .= pack("H4",sprintf("%.4x",$transport_stream_id));
		$section .= pack("H*","c100000000");
		$section .= pack("H4",sprintf("%.4x",$NIT_PID|0xe000));
		$section .= pack("H4",sprintf("%.4x",$program_number));
		$section .= pack("H4",sprintf("%.4x",$OneSegPMT_PID|0xe000));
		$section .= pack("H8",sprintf("%.8x\n",&crc32($section)));
	}
	
	$buf .= pack("H*","474000");
	$buf .= pack("H2",sprintf("%.2x",$continuity_counter));
	$buf .= pack("H2","00");
	$buf .= $section;
	
	while( length($buf) < 188){
		$buf .= pack("H2","ff");
	}
	
	$continuity_counter += 1;
	if ($continuity_counter > 31){
		$continuity_counter = 16;
	}
	
	return $buf;
}

	
sub crc32{
my @crc_table = (
    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
    0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
    0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7,
    0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3,
    0x709f7b7a, 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
    0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 0xbaea46ef,
    0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb,
    0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
    0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
    0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4,
    0x0808d07d, 0x0cc9cdca, 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
    0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08,
    0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc,
    0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
    0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 0xe0b41de7, 0xe4750050,
    0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
    0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
    0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1,
    0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5,
    0x3f9b762c, 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
    0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 0xf5ee4bb9,
    0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd,
    0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
    0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
    0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2,
    0x470cdd2b, 0x43cdc09c, 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
    0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e,
    0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a,
    0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
    0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 0xe3a1cbc1, 0xe760d676,
    0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
    0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
    0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4);

	my $count;
    my $crc = 0xffffffff;

	my @data = unpack("C*",$_[0]);
	my $len = @data;

    for ($count=0; $count < $len; $count++){
#        crc = (crc *(2**8)) ^ crc_table[((crc >> 24) ^ *data++) & 0xff];
#		print STDERR sprintf("count: %d\n",$count);
#		print STDERR sprintf("1st: %.16x\n",(($crc << 8)&0xffffffff));
#		print STDERR sprintf("ind: %.16x\n",(($crc /(2**24)) ^ $data[$count]) & 0xff);
#		print STDERR sprintf("2-1: %.16x\n",($crc /(2**24)));
#		print STDERR sprintf("2-2: %.16x\n",$data[$count]);
#		print STDERR sprintf("2nd: %.16x\n",$crc_table[((($crc /(2**8)) ^ $data[$count]) & 0xff)]);
		$crc = (($crc << 8)&0xffffffff)
			^ $crc_table[((($crc /(2**24)) ^ $data[$count]) & 0xff)];
	}
#	print STDERR sprintf("crc: %.8x\n",$crc);
	return $crc;

}
