codificador en base 64

b64.c

/*
 * b64
 * Angel Rodolfo Pérez Canseco (ikcaro)
 * Algoritmo para codificar datos en base 64
 */
 
#include <stdio.h>
#include <string.h>

#define TBASE	64

static char base_64[TBASE] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

void encodeB64(const unsigned char *m, char *c, int s)
{
	int d = 3 - (s % 3);
	int j = 0;
	int i = 0;
	int t = 0;
	
	while (j < s) {
		t  = (m[j++] << 0x10);
		t += (j < s)? (m[j++] << 0x08): 0;
		t += (j < s)? (m[j++] << 0x00): 0;
		
		c[i++] = base_64[(t >> 0x12) & 0x3F];
		c[i++] = base_64[(t >> 0x0C) & 0x3F];
		c[i++] = base_64[(t >> 0x06) & 0x3F];
		c[i++] = base_64[(t >> 0x00) & 0x3F];
	}
	
	for (j = d; (d < 3) && (j > 0); j--)
		c[i - j] = '=';
	c[i] = 0;
}

int main()
{
	char str[] = "any carnal pleasure.";
	char code[1000];
	
	encodeB64(str, code, strlen(str));
	printf("[%s] => [%s]\n", str, code);
	
	return 0;
}