#include <stdio.h>
#include <stdlib.h>
#include <memory.h>

#define LINE "__________________________________________________________________"

#ifndef VERBOSE_OUTPUT
void printf_info(const char *fmt, ...)
{
    return;
}
#else
#define printf_info printf
#endif

int main(int argc, char **argv)
{
	/************************/
	FILE *input, *output;
	long int filesize, offset_input, length_input, offset_output;
	unsigned char *in_buf, *out_buf;
	/************************/

	if((argc != 5) && (argc != 6)) /* no file provided or too many arguments */
	{
		printf("\n  AAA RIP - Lite DD Clone\n%s\n\n  About: Extract sub-binary from binary\n\n  Syntax: %s \"in\" \"out\" \"offset\" \"length\" \"out offset\"\n\n  Usage:\n  Setting length argument to 0 will write until end of input file.\n  Omitting output offset will overwrite output file.\n  All arguments assume decimal values.", LINE, argv[0]);
		goto exit;
	}
	printf_info("%s\n", LINE);

	/* load input from argument */
	input = fopen(argv[1], "rb");
	if(input == NULL)
	{
		printf("\n  Error: Aborted, input cannot be opened");
		goto exit;
	}
	if(fseek(input, 0, SEEK_END) != 0)
	{
		printf("\n  Error: Aborted, could not find end to input file");
		goto error_input;
	}

	/* load length/offset arguments */
	offset_input = atol(argv[3]);
	length_input = atol(argv[4]);
	offset_output = (argc == 6) ? atol(argv[5]) : 0;
	if(offset_input < 0)
	{
		printf("\n  Error: Aborted, invalid offset argument");
		goto error_input;
	}

	/* get input filesize */
	filesize = ftell(input);
	if(filesize == -1)
	{
		printf("\n  Error: Aborted, could not find length of input file");
		goto error_input;
	}
	if(length_input <= 0)
	{
		length_input = filesize - offset_input;
	}
	if(offset_input >= filesize)
	{
		printf("\n  Error: Aborted, offset goes beyond end of file");
		goto error_input;
	}
	if(offset_input + length_input > filesize)
	{
		printf("\n  Error: Aborted, length goes beyond end of file");
		goto error_input;
	}
	printf_info("\n  Input File: %s\n  Output File: %s\n  Offset: %ld\n  Length: %ld", argv[1], argv[2], offset_input, length_input);
	if(argc == 6)
	{
		printf_info("\n  Output Offset: %ld", offset_output);
	}

	/* read input to file buffer */
	in_buf = (unsigned char *)malloc((size_t)length_input);
	if(in_buf == NULL)
	{
		printf("\n  Error: Aborted, not enough memory to load input");
		goto error_input;
	}
	if(fseek(input, offset_input, SEEK_SET) != 0)
	{
		printf("\n  Error: Aborted, could not set offset position");
		goto error_input;
	}
	fread(in_buf, (size_t)length_input, 1, input);

	/* open output file */
	if(argc == 6)
	{
		output = fopen(argv[2], "rb");
		if(output == NULL)
		{
			printf("\n  Error: Aborted, output file cannot be written");
			goto error_output;
		}
		if(fseek(output, 0, SEEK_END) != 0)
		{
			printf("\n  Error: Aborted, could not find end to output file");
			goto error_offset_output;
		}
		filesize = ftell(output);
		if(fseek(output, 0, SEEK_SET) != 0)
		{
			printf("\n  Error: Aborted, could not set offset position");
			goto error_offset_output;
		}
		if(filesize == -1)
		{
			printf("\n  Error: Aborted, could not find length of output file");
			goto error_offset_output;
		}
		if(length_input + offset_output > filesize)
		{
			filesize = length_input + offset_output;
		}

		/* read output file to buffer */
		out_buf = (unsigned char *)calloc((size_t)filesize, 1);
		if(out_buf == NULL)
		{
			printf("\n  Error: Aborted, not enough memory to load output");
			goto error_offset_output;
		}
		fread(out_buf, (size_t)filesize, 1, output);
		fclose(output);

		memcpy(&out_buf[offset_output], in_buf, (size_t)length_input);

		output = fopen(argv[2], "wb");
		if(output == NULL)
		{
			printf("\n  Error: Aborted, output file cannot be written");
			free(out_buf);
			goto error_output;
		}
		fwrite(out_buf, (size_t)filesize, 1, output);
		free(out_buf);
	}
	else
	{	
		output = fopen(argv[2], "wb");
		if(output == NULL)
		{
			printf("\n  Error: Aborted, output file cannot be written");
			goto error_output;
		}
		fwrite(in_buf, (size_t)length_input, 1, output);
	}

error_offset_output:
	fclose(output);
error_output:
	free(in_buf);
error_input:
	fclose(input);
exit:
	printf_info("\n%s\n", LINE);
	return 0;
}