108 lines
3.0 KiB
C
108 lines
3.0 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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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <stdio.h>
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#include <errno.h>
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#include <assert.h>
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#include <ipxe/string.h>
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#include <ipxe/vsprintf.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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* Encode hexadecimal string (with optional byte separator character)
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*
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* @v separator Byte separator character, or 0 for no separator
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* @v raw Raw data
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* @v raw_len Length of raw data
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* @v data Buffer
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* @v len Length of buffer
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* @ret len Encoded length
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*/
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size_t hex_encode ( char separator, const void *raw, size_t raw_len,
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char *data, size_t len ) {
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const uint8_t *bytes = raw;
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const char delimiter[2] = { separator, '\0' };
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size_t used = 0;
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unsigned int i;
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if ( len )
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data[0] = 0; /* Ensure that a terminating NUL exists */
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for ( i = 0 ; i < raw_len ; i++ ) {
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used += ssnprintf ( ( data + used ), ( len - used ),
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"%s%02x", ( used ? delimiter : "" ),
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bytes[i] );
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}
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return used;
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}
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/**
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* Decode hexadecimal string (with optional byte separator character)
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*
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* @v separator Byte separator character, or 0 for no separator
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* @v encoded Encoded string
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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 ( char separator, const char *encoded, 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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* digit_value(); 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 = digit_value ( *(encoded++) );
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if ( sixteens >= 16 )
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return -EINVAL;
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units = digit_value ( *(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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