1 /* 2 * Copyright (C) 2009 Michael Brown <mbrown (at) fensystems.co.uk>. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License as 6 * published by the Free Software Foundation; either version 2 of the 7 * License, or any later version. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 17 */ 18 19 FILE_LICENCE ( GPL2_OR_LATER ); 20 21 #include <stdint.h> 22 #include <string.h> 23 #include <assert.h> 24 #include <gpxe/base64.h> 25 26 /** @file 27 * 28 * Base64 encoding 29 * 30 */ 31 32 static const char base64[64] = 33 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 34 35 /** 36 * Base64-encode a string 37 * 38 * @v raw Raw string 39 * @v encoded Buffer for encoded string 40 * 41 * The buffer must be the correct length for the encoded string. Use 42 * something like 43 * 44 * char buf[ base64_encoded_len ( strlen ( raw ) ) + 1 ]; 45 * 46 * (the +1 is for the terminating NUL) to provide a buffer of the 47 * correct size. 48 */ 49 void base64_encode ( const char *raw, char *encoded ) { 50 const uint8_t *raw_bytes = ( ( const uint8_t * ) raw ); 51 uint8_t *encoded_bytes = ( ( uint8_t * ) encoded ); 52 size_t raw_bit_len = ( 8 * strlen ( raw ) ); 53 unsigned int bit; 54 unsigned int tmp; 55 56 for ( bit = 0 ; bit < raw_bit_len ; bit += 6 ) { 57 tmp = ( ( raw_bytes[ bit / 8 ] << ( bit % 8 ) ) | 58 ( raw_bytes[ bit / 8 + 1 ] >> ( 8 - ( bit % 8 ) ) ) ); 59 tmp = ( ( tmp >> 2 ) & 0x3f ); 60 *(encoded_bytes++) = base64[tmp]; 61 } 62 for ( ; ( bit % 8 ) != 0 ; bit += 6 ) 63 *(encoded_bytes++) = '='; 64 *(encoded_bytes++) = '\0'; 65 66 DBG ( "Base64-encoded \"%s\" as \"%s\"\n", raw, encoded ); 67 assert ( strlen ( encoded ) == base64_encoded_len ( strlen ( raw ) ) ); 68 } 69
