GRUB2/MOD_SRC/grub-2.04/grub-core/ventoy/xpress.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 "huffman.h"
  31
  32 /** Number of XCA codes */
  33 #define XCA_CODES 512
  34
  35 /** XCA decompressor */
  36 struct xca {
  37         /** Huffman alphabet */
  38         struct huffman_alphabet alphabet;
  39         /** Raw symbols
  40          *
  41          * Must immediately follow the Huffman alphabet.
  42          */
  43         huffman_raw_symbol_t raw[XCA_CODES];
  44         /** Code lengths */
  45         uint8_t lengths[XCA_CODES];
  46 };
  47
  48 /** XCA symbol Huffman lengths table */
  49 struct xca_huf_len {
  50         /** Lengths of each symbol */
  51         uint8_t nibbles[ XCA_CODES / 2 ];
  52 } __attribute__ (( packed ));
  53
  54 /**
  55  * Extract Huffman-coded length of a raw symbol
  56  *
  57  * @v lengths           Huffman lengths table
  58  * @v symbol            Raw symbol
  59  * @ret len             Huffman-coded length
  60  */
  61 static inline unsigned int xca_huf_len ( const struct xca_huf_len *lengths,
  62                                          unsigned int symbol ) {
  63         return ( ( ( lengths->nibbles[ symbol / 2 ] ) >>
  64                    ( 4 * ( symbol % 2 ) ) ) & 0x0f );
  65 }
  66
  67 /** Get word from source data stream */
  68 #define XCA_GET16( src ) ( {                    \
  69         const uint16_t *src16 = src;            \
  70         src = ( uint8_t * ) src + sizeof ( *src16 );            \
  71         *src16; } )
  72
  73 /** Get byte from source data stream */
  74 #define XCA_GET8( src ) ( {                     \
  75         const uint8_t *src8 = src;              \
  76         src = ( uint8_t * ) src + sizeof ( *src8 );             \
  77         *src8; } )
  78
  79 /** XCA source data stream end marker */
  80 #define XCA_END_MARKER 256
  81
  82 /** XCA block size */
  83 #define XCA_BLOCK_SIZE ( 64 * 1024 )
  84
  85 extern ssize_t xca_decompress ( const void *data, size_t len, void *buf );
  86
  87 #endif /* _XCA_H */