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