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89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
#ifndef _XCA_H
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#define _XCA_H
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/*
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* Copyright (C) 2012 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 (at your option) 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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/**
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* @file
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*
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* Xpress Compression Algorithm (MS-XCA) decompression
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*
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*/
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#include <stdint.h>
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#include "huffman.h"
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/** Number of XCA codes */
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#define XCA_CODES 512
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/** XCA decompressor */
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struct xca {
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/** Huffman alphabet */
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struct huffman_alphabet alphabet;
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/** Raw symbols
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*
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* Must immediately follow the Huffman alphabet.
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*/
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huffman_raw_symbol_t raw[XCA_CODES];
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/** Code lengths */
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uint8_t lengths[XCA_CODES];
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};
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/** XCA symbol Huffman lengths table */
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struct xca_huf_len {
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/** Lengths of each symbol */
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uint8_t nibbles[ XCA_CODES / 2 ];
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} __attribute__ (( packed ));
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/**
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* Extract Huffman-coded length of a raw symbol
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*
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* @v lengths Huffman lengths table
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* @v symbol Raw symbol
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* @ret len Huffman-coded length
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*/
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static inline unsigned int xca_huf_len ( const struct xca_huf_len *lengths,
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unsigned int symbol ) {
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return ( ( ( lengths->nibbles[ symbol / 2 ] ) >>
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( 4 * ( symbol % 2 ) ) ) & 0x0f );
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}
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/** Get word from source data stream */
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#define XCA_GET16( src ) ( { \
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const uint16_t *src16 = src; \
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src += sizeof ( *src16 ); \
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*src16; } )
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/** Get byte from source data stream */
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#define XCA_GET8( src ) ( { \
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const uint8_t *src8 = src; \
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src += sizeof ( *src8 ); \
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*src8; } )
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/** XCA source data stream end marker */
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#define XCA_END_MARKER 256
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/** XCA block size */
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#define XCA_BLOCK_SIZE ( 64 * 1024 )
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extern ssize_t xca_decompress ( const void *data, size_t len, void *buf );
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#endif /* _XCA_H */
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