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#include <stdio.h>
#include <fcntl.h>
#define USAGE "USAGE: checkum -[vhcs] infile outfile\n\t-v\tverbose\n\
\t-h\thelp\n\t-c\tcheck checksum\n\t-s\tprint the ipl size"
static int verbose = 0;
static int verify = 0;
static int size = 0;
typedef int word_t;
#define WORDSIZE (sizeof(word_t))
main(argc, argv)
int argc;
char **argv;
{
char *infile;
char *outfile;
int infd;
int outfd;
word_t checksum = 0;
int nbytes;
word_t buf;
int i = 1;
int filesize = 0;
while (*argv[i] == '-') {
switch (*(argv[i]+1)) {
case 'v':
verbose++;
break;
case 'c':
verify++;
puts ("Sorry, unimplemented for now");
exit(1);
break;
case 's':
size++;
break;
case 'h':
puts (USAGE);
exit(0);
default:
printf ("\"%s\", Illegal option\n", argv[i]);
puts (USAGE);
exit(1);
}
i++;
}
infile = *(argv + i);
outfile = *(argv + i+1);
/* see it there were file names on the command line */
if (infile == 0x0) {
puts("Didn't specify an input file name");
exit(1);
}
if (outfile == 0x0) {
puts("Didn't specify an output file name");
exit(1);
}
/* try to open the files */
infd = open(infile, O_RDONLY);
if (infd == -1) {
printf("Couldn't open %s\n", infile);
exit(1);
}
outfd = open(outfile, O_WRONLY|O_CREAT|O_TRUNC);
if (outfd == -1) {
printf("Couldn't open %s\n", outfile);
exit(1);
}
if (verbose > 2)
putchar('\n');
/* calculate the checksum */
while ((nbytes = read(infd, &buf, WORDSIZE)) == WORDSIZE) {
if (verbose > 2)
putchar('.');
checksum+= buf;
filesize+= WORDSIZE;
if (write(outfd, &buf, WORDSIZE) != WORDSIZE) {
puts("Couldn't write");
}
if (verbose > 3)
putchar('+');
}
if (verbose > 2)
putchar('\n');
/* write the last byte read */
if (nbytes > 0) {
write(outfd, &buf, nbytes);
checksum+= buf; /* calculate the last word */
filesize+= nbytes;
}
/* write the checksum */
buf = -checksum;
write(outfd, &buf, WORDSIZE);
filesize+= WORDSIZE; /* checksum increase the size */
if (verbose > 0)
printf("The calculated checksum is:\n\t0x%x,\n\t%u\n", -checksum, -checksum);
/* calculate the extra 2K here */
buf = 0;
while ((filesize % 2048) !=0) {
filesize+=WORDSIZE;
write(outfd, &buf, WORDSIZE);
}
if (size > 0) {
printf ("%u is the new file size\n", filesize);
}
close(outfd);
close(infd);
exit(0);
}
#if 0
/* Calculate a simple checksum and concatenate it to the end of BUF. */
void
compute_and_concatenate_checksum (word *buf, size_t bufsize_in_words)
{
size_t i;
word sum;
sum = buf[0]
for (i = 1; i < bufsize_in_words; i++)
sum += buf[i];
buf[bufsize_in_words] = -sum;
}
/* Calculate a simple checksum and verify it. NOTE: bufsize_in_words should
include the checksum, i.e., it should be one larger than when the
checksum was calculated using compute_and_concatenate_checksum! */
int
compute_and_and_verify_checksum (word *buf, size_t bufsize_in_words)
{
size_t i;
word sum;
sum = buf[0];
for (i = 1; i < bufsize_in_words; i++)
sum += buf[i];
if (sum != 0)
return ERROR;
return SUCCESS;
}
#endif
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