/*
 * Extract
 * Copyright (C) 2013  Adam Williams <broadcast at earthling dot net>
 * 
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 */

#define _LARGEFILE_SOURCE 1
#define _LARGEFILE64_SOURCE 1
#define _FILE_OFFSET_BITS 64
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>

#define BUFFER_SIZE 0x2000000

int64_t get_number(char *text)
{
	int64_t result;
	if(text[0] == '0' && 
		text[1] == 'x')
	{
		sscanf(text, "%llx", &result);
	}
	else
	{
		sscanf(text, "%lld", &result);
	}
	return result;
}

int main(int argc, char *argv[])
{
	int is_bd = 0;
	int buffer_size = BUFFER_SIZE;
	int64_t i;
	int64_t start = -1;
	int64_t end = -1;
	int64_t output_position = 0;
	char *filename = 0;
	int use_stdin = 0;

	for(i = 1; i < argc; i++)
	{
		if(!strcmp(argv[i], "-b"))
		{
			is_bd = 1;
			buffer_size = (BUFFER_SIZE / 2048 / 3) * 2048 * 3;
		}
		else
		if(!filename)
		{
			filename = argv[i];
			if(!strcmp(filename, "-")) use_stdin = 1;
		}
		else
		if(start < 0)
		{
			start = get_number(argv[i]);
		}
		else
		if(end < 0)
		{
			end = get_number(argv[i]);
		}
	}


	if(!filename || start < 0)
	{
		fprintf(stderr, "Usage: extract [-b] filename <start> [end]\n"
			"-b extract transport stream from Blu-Ray stream.\n"
			"Specify - as filename to read from stdin.\n"
			"Start and end may be decimal or prefixed by 0x for hex.\n"
			"Omit the end position to read forever.\n");
		exit(1);
	}

	FILE *file = 0;
	if(use_stdin)
	{
		file = stdin;
	}
	else
	{
		file = fopen64(filename, "r");
		if(!file)
		{
			perror("fopen");
			exit(1);
		}
	}

	unsigned char *buffer = malloc(buffer_size);

	fprintf(stderr, "Extracting %s from %lld (%llx) to ",
		filename,
		start,
		start);

	if(end < 0)
		fprintf(stderr, "infinity.\n");
	else
		fprintf(stderr, "%lld (%llx)\n",
			end,
			end);
	if(is_bd) fprintf(stderr, "Stripping Blu-Ray headers.\n");

	if(!use_stdin)
	{
		fseeko64(file, start, SEEK_SET);
	}
	else
	{
		for(i = 0; i < start; i++)
			fgetc(file);
	}

	i = start;
	while(1)
	{
		int fragment_size = buffer_size;
		if(end > 0 && i + fragment_size > end) fragment_size = end - i;
		fprintf(stderr, "Reading from %llx        \r", i);
		fflush(stdout);
		int bytes_read = fread(buffer, 1, fragment_size, file);

		int output_size = bytes_read;
// Strip Blu-Ray headers
		if(is_bd)
		{
			int j, k;
			output_size = 0;
			for(j = 4, k = 0; j < fragment_size; j += 192, k += 188)
			{
				if(buffer[j] != 0x47)
					fprintf(stderr, "Invalid start code\n");
				memcpy(buffer + k, buffer + j, 188);
				output_size += 188;
			}
		}


		fprintf(stderr, "Writing to %llx         \r", output_position);
		fflush(stdout);
		fwrite(buffer, output_size, 1, stdout);
		output_position += output_size;

		i += buffer_size;
		if(end > 0 && i >= end) break;
		if(end < 0 && bytes_read < fragment_size) break;
	}
	if(!use_stdin) fclose(file);
}