wimboot/wimboot-2.7.3/src/xca.h

   1 #ifndef _XCA_H
   2 #define _XCA_H
   3
   4 /*
   5  * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20  * 02110-1301, USA.
  21  */
  22
  23 /**
  24  * @file
  25  *
  26  * Xpress Compression Algorithm (MS-XCA) decompression
  27  *
  28  */
  29
  30 #include <stdint.h>
  31 #include "huffman.h"
  32
  33 /** Number of XCA codes */
  34 #define XCA_CODES 512
  35
  36 /** XCA decompressor */
  37 struct xca {
  38         /** Huffman alphabet */
  39         struct huffman_alphabet alphabet;
  40         /** Raw symbols
  41          *
  42          * Must immediately follow the Huffman alphabet.
  43          */
  44         huffman_raw_symbol_t raw[XCA_CODES];
  45         /** Code lengths */
  46         uint8_t lengths[XCA_CODES];
  47 };
  48
  49 /** XCA symbol Huffman lengths table */
  50 struct xca_huf_len {
  51         /** Lengths of each symbol */
  52         uint8_t nibbles[ XCA_CODES / 2 ];
  53 } __attribute__ (( packed ));
  54
  55 /**
  56  * Extract Huffman-coded length of a raw symbol
  57  *
  58  * @v lengths           Huffman lengths table
  59  * @v symbol            Raw symbol
  60  * @ret len             Huffman-coded length
  61  */
  62 static inline unsigned int xca_huf_len ( const struct xca_huf_len *lengths,
  63                                          unsigned int symbol ) {
  64         return ( ( ( lengths->nibbles[ symbol / 2 ] ) >>
  65                    ( 4 * ( symbol % 2 ) ) ) & 0x0f );
  66 }
  67
  68 /** Get word from source data stream */
  69 #define XCA_GET16( src ) ( {                    \
  70         const uint16_t *src16 = src;            \
  71         src += sizeof ( *src16 );               \
  72         *src16; } )
  73
  74 /** Get byte from source data stream */
  75 #define XCA_GET8( src ) ( {                     \
  76         const uint8_t *src8 = src;              \
  77         src += sizeof ( *src8 );                \
  78         *src8; } )
  79
  80 /** XCA source data stream end marker */
  81 #define XCA_END_MARKER 256
  82
  83 /** XCA block size */
  84 #define XCA_BLOCK_SIZE ( 64 * 1024 )
  85
  86 extern ssize_t xca_decompress ( const void *data, size_t len, void *buf );
  87
  88 #endif /* _XCA_H */