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/*
* Copyright 2015-2018 Rivoreo
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
// Based on public domain code from Wikibooks
#include "base64.h"
#include <stddef.h>
#include <stdint.h>
int base64_encode(const void *data_buf, size_t data_len, char *result, size_t out_buffer_size, int flags) {
static const char base64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const uint8_t *data = (const uint8_t *)data_buf;
size_t out_i = 0;
size_t x;
uint32_t n = 0;
uint8_t n0, n1, n2, n3;
/* Increment over the length of the string, three characters at a time */
for (x = 0; x < data_len; x += 3) {
/* These three 8-bit (ASCII) characters become one 24-bit number */
/* parenthesis needed; compiler depending on flags can do the
shifting before conversion to uint32_t, resulting to 0 */
n = ((uint32_t)data[x]) << 16;
if((x+1) < data_len) {
/* parenthesis needed; compiler depending on flags
can do the shifting before conversion to uint32_t,
resulting to 0 */
n += ((uint32_t)data[x+1]) << 8;
}
if((x+2) < data_len) n += data[x+2];
/* this 24-bit number gets separated into four 6-bit numbers */
n0 = (uint8_t)(n >> 18) & 63;
n1 = (uint8_t)(n >> 12) & 63;
n2 = (uint8_t)(n >> 6) & 63;
n3 = (uint8_t)n & 63;
/*
* if we have one byte available, then its encoding is spread
* out over two characters
*/
if(out_i >= out_buffer_size) return -1; /* indicate failure: buffer too small */
result[out_i++] = base64chars[n0];
if(out_i >= out_buffer_size) return -1; /* indicate failure: buffer too small */
result[out_i++] = base64chars[n1];
/*
* if we have only two bytes available, then their encoding is
* spread out over three chars
*/
if((x+1) < data_len) {
if(out_i >= out_buffer_size) return -1; /* indicate failure: buffer too small */
result[out_i++] = base64chars[n2];
}
/*
* if we have all three bytes available, then their encoding is spread
* out over four characters
*/
if((x+2) < data_len) {
if(out_i >= out_buffer_size) return -1; /* indicate failure: buffer too small */
result[out_i++] = base64chars[n3];
}
}
if(flags & BASE64_ADD_PADDING) {
/*
* Create and add padding that is required if we did not have a multiple of 3
* number of characters available
*/
int pad_count = data_len % 3;
while(pad_count % 3) {
if(out_i >= out_buffer_size) return -1;
result[out_i++] = '=';
pad_count++;
}
}
if(out_i >= out_buffer_size) return -1; /* indicate failure: buffer too small */
result[out_i] = 0;
return 0; /* indicate success */
}
#define WHITESPACE 64
#define EQUALS 65
#define INVALID 66
static const unsigned char d[] = {
66,66,66,66,66,66,66,66,66,66,64,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,62,66,66,66,63,52,53,
54,55,56,57,58,59,60,61,66,66,66,65,66,66,66, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,66,66,66,66,66,66,26,27,28,
29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,66,66,
66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,66,
66,66,66,66,66,66
};
int base64_decode(const char *in_buffer, size_t in_len, void *out_buffer, size_t buffer_size) {
const char *end = in_buffer + in_len;
unsigned char *out_p = out_buffer;
char iter = 0;
uint32_t buf = 0;
size_t len = 0;
while(in_buffer < end) {
unsigned char c = d[*in_buffer++];
switch(c) {
case WHITESPACE: continue; /* skip whitespace */
case INVALID: return -1; /* invalid input, return error */
case EQUALS: /* pad character, end of data */
in_buffer = end;
continue;
default:
buf = buf << 6 | c;
iter++; // increment the number of iteration
/* If the buffer is full, split it into bytes */
if(iter == 4) {
if(len + 1 > buffer_size) return len;
*(out_p++) = (buf >> 16) & 255;
if(++len + 1 > buffer_size) return len;
*(out_p++) = (buf >> 8) & 255;
if(++len + 1 > buffer_size) return len;
*(out_p++) = buf & 255;
len++;
buf = 0; iter = 0;
}
}
}
if(iter == 3) {
if(len + 1 > buffer_size) return len;
*(out_p++) = (buf >> 10) & 255;
if(++len + 1 > buffer_size) return len;
*(out_p++) = (buf >> 2) & 255;
len++;
} else if(iter == 2) {
if(len + 1 > buffer_size) return len;
*(out_p++) = (buf >> 4) & 255;
len++;
}
return len;
}