130 lines
2.7 KiB
C
130 lines
2.7 KiB
C
/* Copyright (C) 2012 Connor Olding
|
|
*
|
|
* This program is licensed under the terms of the MIT License, and
|
|
* is distributed without any warranty. You should have received a
|
|
* copy of the license along with this program; see the file LICENSE.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#include "crc32.h"
|
|
#include "args.h"
|
|
|
|
#ifdef _MSC_VER
|
|
#define FREOPEN_BLANK ("")
|
|
#else
|
|
#define FREOPEN_BLANK (NULL)
|
|
#endif
|
|
|
|
static ulong remainder = 0xFFFFFFFF;
|
|
|
|
static FILE *input_stream = NULL;
|
|
static char *input_filename = "-";
|
|
static char print_binary = 0;
|
|
static char xor_output = 1;
|
|
static char reflect_output = 0;
|
|
|
|
const char help1[] = "\
|
|
crc32 - a 32-bit cyclic rendundancy check calculator\n\
|
|
\n\
|
|
-h display this text\n\
|
|
-i <file> open file for reading (default: stdin)\n\
|
|
-s <n> start cycle with n (default: 0xFFFFFFFF)\n\
|
|
-p <n> use n as the crc divisor (default: 0x04C11DB7)\n\
|
|
-e use big endian calculations\n\
|
|
-b output as binary\n\
|
|
-x xor the output by 0xFFFFFFFF\n\
|
|
-r reverse the bits of the output\n\
|
|
\n\
|
|
";
|
|
const char help2[] = "\
|
|
numbers <n> may be entered as hexadecimal or octal with prefixes\n\
|
|
";
|
|
|
|
void handle_flag(char flag, char *(*nextarg)()) {
|
|
/* TODO: check for NULL on nextarg */
|
|
switch (flag) {
|
|
case 'h':
|
|
printf(help1);
|
|
printf(help2);
|
|
exit(0);
|
|
case 'i':
|
|
input_filename = nextarg();
|
|
break;
|
|
case 's':
|
|
remainder = strtoul(nextarg(), NULL, 0);
|
|
break;
|
|
case 'p':
|
|
crc_set_polynomial(strtoul(nextarg(), NULL, 0));
|
|
break;
|
|
case 'e':
|
|
crc_set_big_endian();
|
|
break;
|
|
case 'b':
|
|
print_binary = 1;
|
|
break;
|
|
case 'x':
|
|
xor_output = 0;
|
|
break;
|
|
case 'r':
|
|
reflect_output = 1;
|
|
break;
|
|
default:
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
static void open_stream()
|
|
{
|
|
const char mode[] = "rb";
|
|
if (!strcmp(input_filename, "-")) {
|
|
freopen(FREOPEN_BLANK, mode, stdin);
|
|
input_stream = stdin;
|
|
} else {
|
|
input_stream = fopen(input_filename, mode);
|
|
}
|
|
if (input_stream == NULL) {
|
|
fprintf(stderr, "Could not open file for reading: %s\n",
|
|
input_filename);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
static void close_stream()
|
|
{
|
|
fclose(input_stream);
|
|
}
|
|
|
|
static void cycle_input()
|
|
{
|
|
int c;
|
|
open_stream();
|
|
while ((c = getc(input_stream)) != EOF)
|
|
crc_cycle(&remainder, c);
|
|
close_stream();
|
|
|
|
if (xor_output)
|
|
remainder ^= 0xFFFFFFFF;
|
|
if (reflect_output)
|
|
remainder = crc_reflect(remainder);
|
|
}
|
|
|
|
static void print_crc()
|
|
{
|
|
if (print_binary)
|
|
fwrite(&remainder, sizeof(remainder), 1, stdout);
|
|
else
|
|
printf("%08X\n", (int) remainder);
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
crc_set_little_endian();
|
|
args_parse(argc, argv, handle_flag, NULL);
|
|
cycle_input();
|
|
print_crc();
|
|
return 0;
|
|
}
|