1 /* lzo1a_de.h -- definitions for the the LZO1A algorithm 2 3 This file is part of the LZO real-time data compression library. 4 5 Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer 6 All Rights Reserved. 7 8 The LZO library is free software; you can redistribute it and/or 9 modify it under the terms of the GNU General Public License as 10 published by the Free Software Foundation; either version 2 of 11 the License, or (at your option) any later version. 12 13 The LZO library is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with the LZO library; see the file COPYING. 20 If not, write to the Free Software Foundation, Inc., 21 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 22 23 Markus F.X.J. Oberhumer 24 <markus@oberhumer.com> 25 http://www.oberhumer.com/opensource/lzo/ 26 */ 27 28 29 /* WARNING: this file should *not* be used by applications. It is 30 part of the implementation of the LZO package and is subject 31 to change. 32 */ 33 34 35 #ifndef __LZO_DEFS_H 36 #define __LZO_DEFS_H 1 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 43 /*********************************************************************** 44 // 45 ************************************************************************/ 46 47 /* 48 Format of the marker byte 49 50 51 76543210 52 -------- 53 00000000 a long literal run ('R0' run) - there are short and long R0 runs 54 000rrrrr a short literal run with len r 55 mmmooooo a short match (len = 2+m, o = offset low bits) 56 111ooooo a long match (o = offset low bits) 57 */ 58 59 60 #define RSIZE (1 << RBITS) 61 #define RMASK (RSIZE - 1) 62 63 #define MBITS (8 - OBITS) 64 #define MSIZE (1 << MBITS) 65 #define MMASK (MSIZE - 1) 66 67 #define OBITS RBITS /* offset and run-length use same bits */ 68 #define OSIZE (1 << OBITS) 69 #define OMASK (OSIZE - 1) 70 71 72 /* additional bits for coding the length in a long match */ 73 #define LBITS 8 74 #define LSIZE (1 << LBITS) 75 #define LMASK (LSIZE - 1) 76 77 78 /*********************************************************************** 79 // some macros to improve readability 80 ************************************************************************/ 81 82 /* Minimum len of a match */ 83 #define MIN_MATCH 3 84 #define THRESHOLD (MIN_MATCH - 1) 85 86 /* Min-/Maximum len of a match coded in 2 bytes */ 87 #define MIN_MATCH_SHORT (MIN_MATCH) 88 #define MAX_MATCH_SHORT (MIN_MATCH_SHORT + (MSIZE - 2) - 1) 89 /* why (MSIZE - 2) ? because 0 is used to mark runs, 90 * and MSIZE-1 is used to mark a long match */ 91 92 /* Min-/Maximum len of a match coded in 3 bytes */ 93 #define MIN_MATCH_LONG (MAX_MATCH_SHORT + 1) 94 #define MAX_MATCH_LONG (MIN_MATCH_LONG + LSIZE - 1) 95 96 /* Min-/Maximum offset of a match */ 97 #define MIN_OFFSET 1 98 #define MAX_OFFSET (1 << (CHAR_BIT + OBITS)) 99 100 101 /* R0 literal run (a long run) */ 102 103 #define R0MIN (RSIZE) /* Minimum len of R0 run of literals */ 104 #define R0MAX (R0MIN + 255) /* Maximum len of R0 run of literals */ 105 #define R0FAST (R0MAX & ~7) /* R0MAX aligned to 8 byte boundary */ 106 107 #if (R0MAX - R0FAST != 7) || ((R0FAST & 7) != 0) 108 # error "something went wrong" 109 #endif 110 111 /* 7 special codes from R0FAST+1 .. R0MAX 112 * these codes mean long R0 runs with lengths 113 * 512, 1024, 2048, 4096, 8192, 16384, 32768 */ 114 115 116 /* 117 118 RBITS | MBITS MIN THR. MSIZE MAXS MINL MAXL MAXO R0MAX R0FAST 119 ======+=============================================================== 120 3 | 5 3 2 32 32 33 288 2048 263 256 121 4 | 4 3 2 16 16 17 272 4096 271 264 122 5 | 3 3 2 8 8 9 264 8192 287 280 123 124 */ 125 126 127 /*********************************************************************** 128 // 129 ************************************************************************/ 130 131 #define DBITS 13 132 #include "lzo_dict.h" 133 #define DVAL_LEN DVAL_LOOKAHEAD 134 135 136 137 #ifdef __cplusplus 138 } /* extern "C" */ 139 #endif 140 141 #endif /* already included */ 142 143 144 /* vim:set ts=4 sw=4 et: */ 145