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/*
* UNG's Not GNU
*
* Copyright (c) 2011-2017, Jakob Kaivo <jkk@ung.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#define _POSIX_C_SOURCE 200809L
#include <errno.h>
#include <inttypes.h>
#include <libgen.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#define MAX_SUM_WIDTH (32)
#define UINT32_BIT (32)
#define UINT16_BIT (16)
#define BLOCK_SIZE (512)
enum algorithm { UNSPECIFIED, ALTERNATIVE, CRC32 };
struct sum {
uintmax_t size;
uintmax_t sum;
};
static char *progname = NULL;
static uint32_t reverse(uint32_t n, int width)
{
uint32_t r = 0;
for (int i = 0; i < width; i++) {
r |= (n & 0x1) << ((width - 1) - i);
n >>= 1;
}
return r;
}
static struct sum sum_crc32(FILE *f)
{
const uint32_t polynomial = 0x04c11db7;
uint32_t crc = UINT32_MAX;
struct sum sum = { 0 };
int c;
while ((c = fgetc(f)) != EOF) {
sum.size++;
crc ^= reverse((uint8_t)c, CHAR_BIT) << (UINT32_BIT - CHAR_BIT);
for (int i = 0; i < CHAR_BIT; i++) {
if (crc & (1 << (UINT32_BIT - 1))) {
crc = (crc << 1) ^ polynomial;
} else {
crc = (crc << 1);
}
}
}
crc = reverse(crc, CHAR_BIT * sizeof(crc)) ^ UINT32_MAX;
sum.sum = crc;
return sum;
}
static struct sum sum_obsolete(FILE *f, int alt)
{
struct sum sum = { 0 };
int c;
while ((c = fgetc(f)) != EOF) {
sum.size++;
if (alt) {
sum.sum = (sum.sum >> 1) +
((sum.sum & 1) << (UINT16_BIT - 1));
}
sum.sum += c;
if (alt) {
sum.sum &= UINT16_MAX;
}
}
sum.sum = (sum.sum & UINT16_MAX) + (sum.sum >> UINT16_BIT);
/* obsolete sum program prints number of 512 byte blocks */
if (sum.size % BLOCK_SIZE != 0) {
sum.size += BLOCK_SIZE;
}
sum.size /= BLOCK_SIZE;
return sum;
}
static struct sum sum_unspecified(FILE *f)
{
return sum_obsolete(f, 0);
}
static struct sum sum_alternative(FILE *f)
{
return sum_obsolete(f, 1);
}
int cksum(const char *path, enum algorithm alg)
{
FILE *f = stdin;
if (path && strcmp(path, "-")) {
f = fopen(path, "rb");
}
if (f == NULL) {
fprintf(stderr, "%s: %s: %s\n", progname, path, strerror(errno));
return 1;
}
struct sum sum;
switch (alg) {
case UNSPECIFIED:
sum = sum_unspecified(f);
break;
case ALTERNATIVE:
sum = sum_alternative(f);
break;
case CRC32:
sum = sum_crc32(f);
break;
default:
break;
}
printf("%"PRIuMAX" %"PRIuMAX"", sum.sum, sum.size);
if (f != stdin) {
printf(" %s", path);
fclose(f);
}
putchar('\n');
return 0;
}
int sum_main(int argc, char *argv[])
{
fprintf(stderr, "sum: utility is obsolete; use cksum\n");
enum algorithm alg = UNSPECIFIED;
int c;
while ((c = getopt(argc, argv, "r")) != -1) {
switch (c) {
case 'r':
alg = ALTERNATIVE;
break;
default:
return 1;
}
}
int r = 0;
do {
r |= cksum(argv[optind++], alg);
} while (optind < argc);
return r;
}
int main(int argc, char *argv[])
{
setlocale(LC_ALL, "");
progname = basename(argv[0]);
if (!strcmp(progname, "sum")) {
return sum_main(argc, argv);
}
while (getopt(argc, argv, "") != -1) {
return 1;
}
int r = 0;
do {
r |= cksum(argv[optind++], CRC32);
} while (optind < argc);
return r;
}
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