os_labs/lab6/check-csum.c

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2020-06-10 20:30:09 +10:00
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "crc8.h"
#define USAGE_STRING "Usage: %s <input_file> <checksum_file>\n"
#define MAX(a,b) ((a)>(b)?(a):(b))
#define STR_EQ(a, b) (!strcmp((a),(b)))
#define WARNING(fmt, ...) fprintf(stderr,fmt,##__VA_ARGS__)
#define FATAL(fmt, ...) do {\
WARNING(fmt,##__VA_ARGS__);\
exit(1);\
} while (0)
int main(int argc, char *argv[]) {
if (argc != 3) {
FATAL(USAGE_STRING, argv[0]);
}
FILE *f = fopen(argv[1], "rb");
if (f == NULL) {
perror("fopen()");
FATAL("Could not open %s\n", argv[1]);
}
FILE *csfile = fopen(argv[2], "rb");
if (csfile == NULL) {
perror("fopen()");
FATAL("Could not open %s\n", argv[2]);
}
int rsize = 0;
uint8_t buf[4096] = {0};
int blocks_read = 0;
uint8_t s;
uint8_t block_cs;
while ((rsize = fread(buf, 1, 4096, f)) == 4096) {
s = 0;
for (int i = 0; i < 4096; ++i) {
CRC8_MAXIM_ITER(s, buf[i]);
}
if (!fread(&block_cs, 1, 1, csfile)) {
FATAL("Unexpected end of checksum file\n");
}
if (s != block_cs) {
WARNING("Checksum mismatch at 4K-block #%d: got 0x%02x, expected 0x%02x\n", blocks_read, s, block_cs);
}
++blocks_read;
}
if (rsize > 0) {
s = 0;
for (int i = 0; i < rsize; ++i) {
CRC8_MAXIM_ITER(s, buf[i]);
}
if (!fread(&block_cs, 1, 1, csfile)) {
FATAL("Unexpected end of checksum file\n");
}
if (s != block_cs) {
WARNING("Checksum mismatch at 4K-block #%d: got 0x%02x, expected 0x%02x\n", blocks_read, s, block_cs);
}
}
fclose(f);
fclose(csfile);
}