/*
* Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 2 of the
* License, or 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/base64.h>
/** @file
*
* Base64 encoding
*
*/
static const char base64[64] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/**
* Base64-encode data
*
* @v raw Raw data
* @v raw_len Length of raw data
* @v data Buffer
* @v len Length of buffer
* @ret len Encoded length
*/
size_t base64_encode ( const void *raw, size_t raw_len, char *data,
size_t len ) {
const uint8_t *raw_bytes = ( ( const uint8_t * ) raw );
size_t raw_bit_len = ( 8 * raw_len );
size_t used = 0;
unsigned int bit;
unsigned int byte;
unsigned int shift;
unsigned int tmp;
for ( bit = 0 ; bit < raw_bit_len ; bit += 6, used++ ) {
byte = ( bit / 8 );
shift = ( bit % 8 );
tmp = ( raw_bytes[byte] << shift );
if ( ( byte + 1 ) < raw_len )
tmp |= ( raw_bytes[ byte + 1 ] >> ( 8 - shift ) );
tmp = ( ( tmp >> 2 ) & 0x3f );
if ( used < len )
data[used] = base64[tmp];
}
for ( ; ( bit % 8 ) != 0 ; bit += 6, used++ ) {
if ( used < len )
data[used] = '=';
}
if ( used < len )
data[used] = '\0';
if ( len )
data[ len - 1 ] = '\0'; /* Ensure terminator exists */
return used;
}
/**
* Base64-decode string
*
* @v encoded Encoded string
* @v data Buffer
* @v len Length of buffer
* @ret len Length of data, or negative error
*/
int base64_decode ( const char *encoded, void *data, size_t len ) {
const char *in = encoded;
uint8_t *out = data;
uint8_t in_char;
char *match;
int in_bits;
unsigned int bit = 0;
unsigned int pad_count = 0;
size_t offset;
/* Zero the output buffer */
memset ( data, 0, len );
/* Decode string */
while ( ( in_char = *(in++) ) ) {
/* Ignore whitespace characters */
if ( isspace ( in_char ) )
continue;
/* Process pad characters */
if ( in_char == '=' ) {
if ( pad_count >= 2 ) {
DBG ( "Base64-encoded string \"%s\" has too "
"many pad characters\n", encoded );
return -EINVAL;
}
pad_count++;
bit -= 2; /* unused_bits = ( 2 * pad_count ) */
continue;
}
if ( pad_count ) {
DBG ( "Base64-encoded string \"%s\" has invalid pad "
"sequence\n", encoded );
return -EINVAL;
}
/* Process normal characters */
match = strchr ( base64, in_char );
if ( ! match ) {
DBG ( "Base64-encoded string \"%s\" contains invalid "
"character '%c'\n", encoded, in_char );
return -EINVAL;
}
in_bits = ( match - base64 );
/* Add to raw data */
in_bits <<= 2;
offset = ( bit / 8 );
if ( offset < len )
out[offset] |= ( in_bits >> ( bit % 8 ) );
offset++;
if ( offset < len )
out[offset] |= ( in_bits << ( 8 - ( bit % 8 ) ) );
bit += 6;
}
/* Check that we decoded a whole number of bytes */
if ( ( bit % 8 ) != 0 ) {
DBG ( "Base64-encoded string \"%s\" has invalid bit length "
"%d\n", encoded, bit );
return -EINVAL;
}
/* Return length in bytes */
return ( bit / 8 );
}
