Problem - Kevin Tafuro

If the length of the input string isn’t a multiple of three bytes, the leftover bits are
padded to a multiple of six with zeros; then the last character is encoded. If only one
byte would have been needed in the input to make it a multiple of three, the pad
character (=) is added to the end of the string. Otherwise, two pad characters are
added.
#include
static char b64table[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
/* Accepts a binary buffer with an associated size.
* Returns a base64 encoded, NULL-terminated string.
*/
unsigned char *spc_base64_encode(unsigned char *input, size_t len, int wrap) {
unsigned char *output, *p;
size_t i = 0, mod = len % 3, toalloc;
toalloc = (len / 3) * 4 + (3 - mod) % 3 + 1;
if (wrap) {
toalloc += len / 57;
if (len % 57) toalloc++;
}
p = output = (unsigned char *)malloc(((len / 3) + (mod ? 1 : 0)) * 4 + 1);
if (!p) return 0;
while (i < len - mod) {
*p++ = b64table[input[i++] >> 2];
*p++ = b64table[((input[i - 1] > 4)) & 0x3f];
*p++ = b64table[((input[i] > 6)) & 0x3f];
*p++ = b64table[input[i + 1] & 0x3f];
i += 2;
if (wrap && !(i % 57)) *p++ = '\n';
}
if (!mod) {
if (wrap && i % 57) *p++ = '\n';
*p = 0;
return output;
} else {
*p++ = b64table[input[i++] >> 2];
*p++ = b64table[((input[i - 1] > 4)) & 0x3f];
if (mod = = 1) {
*p++ = '=';
*p++ = '=';
if (wrap) *p++ = '\n';
*p = 0;
return output;
} else {
*p++ = b64table[(input[i]