Hash bobo do exercicício 4 da aula-21

naive-hash.c

#include <stdio.h>

#define BUFFER_SIZE 	4098
#define ERROR_MSG 	"Não pôde abrir o arquivo %s.\n"
#define USAGE_MSG	"USAGE: %s <file> [file ...]\n"

unsigned char naive_hash(char* filename){
	FILE* file = fopen(filename, "r");

	if(!file){
		fprintf(stderr, ERROR_MSG, filename);
		return 0;
	}
	
	char buffer[BUFFER_SIZE];
	unsigned int n_data;

	unsigned char hash = 0;

	int i;
	while((n_data = fread(buffer, sizeof(unsigned char), BUFFER_SIZE, file)))
		for(i=0; i<n_data; i++)
			hash ^= buffer[i];

	fclose(file);
	return hash;
}

int main(int argc, char* argv[]){

	int i;

	if(argc <= 1){
		printf(USAGE_MSG, argv[0]);
		return 1;		
	}

	for(i=1; i<argc; i++){
		printf("%x\t|\t%s\n", naive_hash(argv[i]), argv[i]);
	}

	return 0;
}