90 lines
2.0 KiB
C
90 lines
2.0 KiB
C
|
include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
|
||
|
|
void deplacerPremierOctet(const char *filename) {
|
||
|
|
FILE *file;
|
||
|
|
unsigned char first_byte;
|
||
|
|
long file_size;
|
||
|
|
unsigned char *buffer;
|
||
|
|
|
||
|
|
|
||
|
|
file = fopen(filename, "r+b");
|
||
|
|
if (file == NULL) {
|
||
|
|
perror("Erreur d'ouverture");
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (fread(&first_byte, 1, 1, file) != 1) {
|
||
|
|
perror("Erreur de lecture");
|
||
|
|
fclose(file);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
fseek(file, 0, SEEK_END);
|
||
|
|
if (fwrite(&first_byte, 1, 1, file) != 1) {
|
||
|
|
perror("Erreur d'écriture");
|
||
|
|
fclose(file);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
file_size = ftell(file);
|
||
|
|
fclose(file);
|
||
|
|
|
||
|
|
file = fopen(filename, "r+b");
|
||
|
|
if (file == NULL) {
|
||
|
|
perror("Erreur d'ouverture");
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
buffer = (unsigned char *)malloc(file_size - 1);
|
||
|
|
if (buffer == NULL) {
|
||
|
|
perror("Erreur d'allocation mémoire");
|
||
|
|
fclose(file);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
fseek(file, 1, SEEK_SET);
|
||
|
|
if (fread(buffer, 1, file_size - 1, file) != file_size - 1) {
|
||
|
|
perror("Erreur de lecture");
|
||
|
|
free(buffer);
|
||
|
|
fclose(file);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
fclose(file);
|
||
|
|
|
||
|
|
file = fopen(filename, "wb");
|
||
|
|
if (file == NULL) {
|
||
|
|
perror("Erreur d'ouverture");
|
||
|
|
free(buffer);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (fwrite(buffer, 1, file_size - 1, file) != file_size - 1) {
|
||
|
|
perror("Erreur d'écriture");
|
||
|
|
free(buffer);
|
||
|
|
fclose(file);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (fwrite(&first_byte, 1, 1, file) != 1) {
|
||
|
|
perror("Erreur d'écriture");
|
||
|
|
free(buffer);
|
||
|
|
fclose(file);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
free(buffer);
|
||
|
|
fclose(file);
|
||
|
|
|
||
|
|
printf("Modification effectuée.\n");
|
||
|
|
}
|
||
|
|
|
||
|
|
int main(int argc, char *argv[]) {
|
||
|
|
if (argc != 2) {
|
||
|
|
fprintf(stderr, "Usage: %s <toto.c>\n", argv[0]);
|
||
|
|
exit(EXIT_FAILURE);
|
||
|
|
}
|
||
|
|
|
||
|
|
deplacerPremierOctet(argv[1]);
|
||
|
|
return 0;
|
||
|
|
}
|