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Diffstat (limited to 'roms/ipxe/src/core/base64.c')
| -rw-r--r-- | roms/ipxe/src/core/base64.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/roms/ipxe/src/core/base64.c b/roms/ipxe/src/core/base64.c new file mode 100644 index 00000000..bdaf7095 --- /dev/null +++ b/roms/ipxe/src/core/base64.c @@ -0,0 +1,161 @@ +/* + * 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. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +#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 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[ base64_encoded_len ( len ) + 1 ]; + * + * (the +1 is for the terminating NUL) to provide a buffer of the + * correct size. + */ +void base64_encode ( const uint8_t *raw, size_t len, char *encoded ) { + const uint8_t *raw_bytes = ( ( const uint8_t * ) raw ); + uint8_t *encoded_bytes = ( ( uint8_t * ) encoded ); + size_t raw_bit_len = ( 8 * len ); + unsigned int bit; + unsigned int byte; + unsigned int shift; + unsigned int tmp; + + for ( bit = 0 ; bit < raw_bit_len ; bit += 6 ) { + byte = ( bit / 8 ); + shift = ( bit % 8 ); + tmp = ( raw_bytes[byte] << shift ); + if ( ( byte + 1 ) < len ) + tmp |= ( raw_bytes[ byte + 1 ] >> ( 8 - shift ) ); + tmp = ( ( tmp >> 2 ) & 0x3f ); + *(encoded_bytes++) = base64[tmp]; + } + for ( ; ( bit % 8 ) != 0 ; bit += 6 ) + *(encoded_bytes++) = '='; + *(encoded_bytes++) = '\0'; + + DBG ( "Base64-encoded to \"%s\":\n", encoded ); + DBG_HDA ( 0, raw, len ); + assert ( strlen ( encoded ) == base64_encoded_len ( len ) ); +} + +/** + * Base64-decode string + * + * @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[ base64_decoded_max_len ( encoded ) ]; + * + * to provide a buffer of the correct size. + */ +int base64_decode ( const char *encoded, uint8_t *raw ) { + const uint8_t *encoded_bytes = ( ( const uint8_t * ) encoded ); + uint8_t *raw_bytes = ( ( uint8_t * ) raw ); + uint8_t encoded_byte; + char *match; + int decoded; + unsigned int bit = 0; + unsigned int pad_count = 0; + size_t len; + + /* Zero the raw data */ + memset ( raw, 0, base64_decoded_max_len ( encoded ) ); + + /* Decode string */ + while ( ( encoded_byte = *(encoded_bytes++) ) ) { + + /* Ignore whitespace characters */ + if ( isspace ( encoded_byte ) ) + continue; + + /* Process pad characters */ + if ( encoded_byte == '=' ) { + 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, encoded_byte ); + if ( ! match ) { + DBG ( "Base64-encoded string \"%s\" contains invalid " + "character '%c'\n", encoded, encoded_byte ); + return -EINVAL; + } + decoded = ( match - base64 ); + + /* Add to raw data */ + decoded <<= 2; + raw_bytes[ bit / 8 ] |= ( decoded >> ( bit % 8 ) ); + raw_bytes[ bit / 8 + 1 ] |= ( decoded << ( 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; + } + len = ( bit / 8 ); + + DBG ( "Base64-decoded \"%s\" to:\n", encoded ); + DBG_HDA ( 0, raw, len ); + assert ( len <= base64_decoded_max_len ( encoded ) ); + + /* Return length in bytes */ + return ( len ); +} |