/*====================================================================*
*
* uint32_t fdchecksum32 (int fd, size_t extent, uint32_t checksum);
*
* memory.h
*
* return the 32-bit checksum of a file region starting from the
* current file position; extent is specified in bytes but will be
* rounded to a multiple of four bytes;
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
#ifndef FDCHECKSUM32_SOURCE
#define FDCHECKSUM32_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include "../tools/memory.h"
uint32_t fdchecksum32 (int fd, register size_t extent, register uint32_t checksum)
{
uint32_t memory;
while (extent >= sizeof (memory))
{
if (read (fd, &memory, sizeof (memory)) != sizeof (memory))
{
return (-1);
}
extent -= sizeof (memory);
checksum ^= memory;
}
return (~checksum);
}
#endif