/***************************************************************************
* base64.c -- Base64 encoding. *
***********************IMPORTANT NMAP LICENSE TERMS************************
* *
* The Nmap Security Scanner is (C) 1996-2012 Insecure.Com LLC. Nmap is *
* also a registered trademark of Insecure.Com LLC. This program is free *
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***************************************************************************/
/* $Id$ */
#include "base64.h"
#include "nbase.h"
static int b64enc_internal(const unsigned char *data, int len, char *dest)
{
/* base64 alphabet, taken from rfc3548 */
char *b64alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
char *buf = dest;
/* Encode three bytes per iteration ala rfc3548. */
while (len >= 3) {
buf[0] = b64alpha[(data[0] >> 2) & 0x3f];
buf[1] = b64alpha[((data[0] << 4) & 0x30) | ((data[1] >> 4) & 0xf)];
buf[2] = b64alpha[((data[1] << 2) & 0x3c) | ((data[2] >> 6) & 0x3)];
buf[3] = b64alpha[data[2] & 0x3f];
data += 3;
buf += 4;
len -= 3;
}
/* Pad the remaining bytes. len is 0, 1, or 2 here. */
if (len > 0) {
buf[0] = b64alpha[(data[0] >> 2) & 0x3f];
if (len > 1) {
buf[1] = b64alpha[((data[0] << 4) & 0x30) | ((data[1] >> 4) & 0xf)];
buf[2] = b64alpha[(data[1] << 2) & 0x3c];
} else {
buf[1] = b64alpha[(data[0] << 4) & 0x30];
buf[2] = '=';
}
buf[3] = '=';
buf += 4;
}
/*
* As mentioned in rfc3548, we need to be careful about
* how we null terminate and handle embedded null-termination.
*/
*buf = '\0';
return (buf - dest);
}
/* Take in plain text and encode into base64. */
char *b64enc(const unsigned char *data, int len)
{
char *dest;
/* malloc enough space to do something useful */
dest = (char *) safe_malloc(4 * len / 3 + 4);
dest[0] = '\0';
/* Call internal function to base64 encode data */
b64enc_internal(data, len, dest);
return (dest);
}