/*
* Copyright (C) 2010 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.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <ipxe/base16.h>
/** @file
*
* Base16 encoding
*
*/
/**
* Base16-encode data
*
* @v raw Raw data
* @v len Length of raw data
* @v encoded Buffer for encoded string
*
* The buffer must be the correct length for the encoded string. Use
* something like
*
* char buf[ base16_encoded_len ( len ) + 1 ];
*
* (the +1 is for the terminating NUL) to provide a buffer of the
* correct size.
*/
void base16_encode ( const uint8_t *raw, size_t len, char *encoded ) {
const uint8_t *raw_bytes = raw;
char *encoded_bytes = encoded;
size_t remaining = len;
/* Encode each byte */
for ( ; remaining-- ; encoded_bytes += 2 ) {
sprintf ( encoded_bytes, "%02x", *(raw_bytes++) );
}
/* Ensure terminating NUL exists even if length was zero */
*encoded_bytes = '\0';
DBG ( "Base16-encoded to \"%s\":\n", encoded );
DBG_HDA ( 0, raw, len );
assert ( strlen ( encoded ) == base16_encoded_len ( len ) );
}
/**
* Decode hexadecimal string
*
* @v encoded Encoded string
* @v separator Byte separator character, or 0 for no separator
* @v data Buffer
* @v len Length of buffer
* @ret len Length of data, or negative error
*/
int hex_decode ( const char *encoded, char separator, void *data, size_t len ) {
uint8_t *out = data;
unsigned int count = 0;
unsigned int sixteens;
unsigned int units;
while ( *encoded ) {
/* Check separator, if applicable */
if ( count && separator && ( ( *(encoded++) != separator ) ) )
return -EINVAL;
/* Extract digits. Note that either digit may be NUL,
* which would be interpreted as an invalid value by
* strtoul_charval(); there is therefore no need for an
* explicit end-of-string check.
*/
sixteens = strtoul_charval ( *(encoded++) );
if ( sixteens >= 16 )
return -EINVAL;
units = strtoul_charval ( *(encoded++) );
if ( units >= 16 )
return -EINVAL;
/* Store result */
if ( count < len )
out[count] = ( ( sixteens << 4 ) | units );
count++;
}
return count;
}
/**
* Base16-decode data
*
* @v encoded Encoded string
* @v raw Raw data
* @ret len Length of raw data, or negative error
*
* The buffer must be large enough to contain the decoded data. Use
* something like
*
* char buf[ base16_decoded_max_len ( encoded ) ];
*
* to provide a buffer of the correct size.
*/
int base16_decode ( const char *encoded, uint8_t *raw ) {
int len;
len = hex_decode ( encoded, 0, raw, -1UL );
if ( len < 0 )
return len;
DBG ( "Base16-decoded \"%s\" to:\n", encoded );
DBG_HDA ( 0, raw, len );
assert ( len <= ( int ) base16_decoded_max_len ( encoded ) );
return len;
}
