//----------------------------------------------------------------
//	dump.cpp
//
//	Dumps a specified file in hexadecimal and ascii formats.
//
//	programmer: ALLAN CRUSE
//	written on: 18 JAN 2003
//----------------------------------------------------------------

#include <stdio.h>	// for printf(), perror()
#include <fcntl.h>	// for open(), O_RDONLY
#include <unistd.h>	// for lseek(), close()
#include <stdlib.h>	// for exit()
#include <sys/mman.h>	// for mmap(), munmap()

int main( int argc, char *argv[] )
{
	// check for mandatory command-line argument
	if ( argc == 1 ) 
		{
		printf( "You must specify an input-file\n" );
		exit(1);
		}
	
	// map the specified input-file to user's address-space
	int	fd = open( argv[1], O_RDONLY );
	if ( fd < 0 ) { perror( "open" ); exit(1); }
	int	filesize = lseek( fd, 0, SEEK_END );
	void	*in = mmap( NULL, filesize, PROT_READ, MAP_PRIVATE, fd, 0 );
	if ( in == (void*)(-1) ) { perror( "mmap" ); exit(1); }
	close( fd );
	
	// display title for the screen output
	printf( "\nFILE DUMP: %s (%d bytes)\n", argv[1], filesize );
	
	// main loop to display hex and ascii dump
	unsigned char	*cp = (unsigned char*)in;
	for (int i = 0; i < filesize; i += 16)
		{
		int	j;
		printf( "\n%08X: ", i );
		for (j = 0; j < 16; j++) 
			{
			if ( i+j < filesize ) printf( "%02X ", cp[i+j] );
			else	printf( "   " );
			}
		printf( " " );
		for (j = 0; j < 16; j++)
			{
			unsigned char	ch = (i+j < filesize) ? cp[i+j] : ' ';
			if (( ch < 0x20 )||( ch > 0x7E )) ch = '.';	
			printf( "%c", ch );
			}	
		}
	printf( "\n\n" );
	
	// unmap the memory-mapped input-file	
	munmap( in, filesize );
}