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/*
* 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.
*
* 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 <stdio.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/string.h>
#include <ipxe/vsprintf.h>
#include <ipxe/base16.h>
/** @file
*
* Base16 encoding
*
*/
/**
* Encode hexadecimal string (with optional byte separator character)
*
* @v separator Byte separator character, or 0 for no separator
* @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 hex_encode ( char separator, const void *raw, size_t raw_len,
char *data, size_t len ) {
const uint8_t *bytes = raw;
const char delimiter[2] = { separator, '\0' };
size_t used = 0;
unsigned int i;
if ( len )
data[0] = 0; /* Ensure that a terminating NUL exists */
for ( i = 0 ; i < raw_len ; i++ ) {
used += ssnprintf ( ( data + used ), ( len - used ),
"%s%02x", ( used ? delimiter : "" ),
bytes[i] );
}
return used;
}
/**
* Decode hexadecimal string (with optional byte separator character)
*
* @v separator Byte separator character, or 0 for no separator
* @v encoded Encoded string
* @v data Buffer
* @v len Length of buffer
* @ret len Length of data, or negative error
*/
int hex_decode ( char separator, const char *encoded, 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
* digit_value(); there is therefore no need for an
* explicit end-of-string check.
*/
sixteens = digit_value ( *(encoded++) );
if ( sixteens >= 16 )
return -EINVAL;
units = digit_value ( *(encoded++) );
if ( units >= 16 )
return -EINVAL;
/* Store result */
if ( count < len )
out[count] = ( ( sixteens << 4 ) | units );
count++;
}
return count;
}
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