136 lines
3.4 KiB
C
136 lines
3.4 KiB
C
/*
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* Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include <ipxe/base16.h>
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/** @file
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*
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* Base16 encoding
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*
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*/
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/**
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* Base16-encode data
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*
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* @v raw Raw data
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* @v len Length of raw data
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* @v encoded Buffer for encoded string
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*
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* The buffer must be the correct length for the encoded string. Use
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* something like
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*
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* char buf[ base16_encoded_len ( len ) + 1 ];
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*
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* (the +1 is for the terminating NUL) to provide a buffer of the
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* correct size.
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*/
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void base16_encode ( const uint8_t *raw, size_t len, char *encoded ) {
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const uint8_t *raw_bytes = raw;
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char *encoded_bytes = encoded;
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size_t remaining = len;
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/* Encode each byte */
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for ( ; remaining-- ; encoded_bytes += 2 ) {
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sprintf ( encoded_bytes, "%02x", *(raw_bytes++) );
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}
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/* Ensure terminating NUL exists even if length was zero */
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*encoded_bytes = '\0';
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DBG ( "Base16-encoded to \"%s\":\n", encoded );
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DBG_HDA ( 0, raw, len );
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assert ( strlen ( encoded ) == base16_encoded_len ( len ) );
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}
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/**
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* Decode hexadecimal string
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*
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* @v encoded Encoded string
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* @v separator Byte separator character, or 0 for no separator
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* @v data Buffer
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* @v len Length of buffer
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* @ret len Length of data, or negative error
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*/
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int hex_decode ( const char *encoded, char separator, void *data, size_t len ) {
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uint8_t *out = data;
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unsigned int count = 0;
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unsigned int sixteens;
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unsigned int units;
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while ( *encoded ) {
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/* Check separator, if applicable */
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if ( count && separator && ( ( *(encoded++) != separator ) ) )
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return -EINVAL;
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/* Extract digits. Note that either digit may be NUL,
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* which would be interpreted as an invalid value by
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* strtoul_charval(); there is therefore no need for an
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* explicit end-of-string check.
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*/
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sixteens = strtoul_charval ( *(encoded++) );
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if ( sixteens >= 16 )
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return -EINVAL;
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units = strtoul_charval ( *(encoded++) );
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if ( units >= 16 )
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return -EINVAL;
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/* Store result */
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if ( count < len )
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out[count] = ( ( sixteens << 4 ) | units );
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count++;
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}
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return count;
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}
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/**
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* Base16-decode data
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*
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* @v encoded Encoded string
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* @v raw Raw data
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* @ret len Length of raw data, or negative error
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*
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* The buffer must be large enough to contain the decoded data. Use
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* something like
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*
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* char buf[ base16_decoded_max_len ( encoded ) ];
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*
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* to provide a buffer of the correct size.
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*/
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int base16_decode ( const char *encoded, uint8_t *raw ) {
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int len;
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len = hex_decode ( encoded, 0, raw, -1UL );
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if ( len < 0 )
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return len;
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DBG ( "Base16-decoded \"%s\" to:\n", encoded );
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DBG_HDA ( 0, raw, len );
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assert ( len <= base16_decoded_max_len ( encoded ) );
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return len;
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}
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