3 * This file is part of the AVR-Crypto-Lib.
4 * Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * base64 encoder (RFC3548)
29 #include "base64_enc.h"
32 #include <avr/pgmspace.h>
34 const char base64_alphabet[64] PROGMEM = {
35 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
36 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
37 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
38 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
39 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
40 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
41 'w', 'x', 'y', 'z', '0', '1', '2', '3',
42 '4', '5', '6', '7', '8', '9', '+', '/' };
45 char bit6toAscii(uint8_t a)
48 return pgm_read_byte(base64_alphabet + a);
54 char bit6toAscii(uint8_t a) {
69 return '/'; /* a == 63 */
78 void base64enc(char *dest, const void *src, uint16_t length)
82 for (i = 0; i < length / 3; ++i) {
83 a[0] = (((uint8_t*) src)[i * 3 + 0]) >> 2;
84 a[1] = (((((uint8_t*) src)[i * 3 + 0]) << 4)
85 | ((((uint8_t*) src)[i * 3 + 1]) >> 4)) & 0x3F;
86 a[2] = (((((uint8_t*) src)[i * 3 + 1]) << 2)
87 | ((((uint8_t*) src)[i * 3 + 2]) >> 6)) & 0x3F;
88 a[3] = (((uint8_t*) src)[i * 3 + 2]) & 0x3F;
89 for (j = 0; j < 4; ++j) {
90 *dest++ = bit6toAscii(a[j]);
93 /* now we do the rest */
98 a[0] = (((uint8_t*) src)[i * 3 + 0]) >> 2;
99 a[1] = ((((uint8_t*) src)[i * 3 + 0]) << 4) & 0x3F;
100 *dest++ = bit6toAscii(a[0]);
101 *dest++ = bit6toAscii(a[1]);
106 a[0] = (((uint8_t*) src)[i * 3 + 0]) >> 2;
107 a[1] = (((((uint8_t*) src)[i * 3 + 0]) << 4)
108 | ((((uint8_t*) src)[i * 3 + 1]) >> 4)) & 0x3F;
109 a[2] = ((((uint8_t*) src)[i * 3 + 1]) << 2) & 0x3F;
110 *dest++ = bit6toAscii(a[0]);
111 *dest++ = bit6toAscii(a[1]);
112 *dest++ = bit6toAscii(a[2]);
115 default: /* this will not happen! */